glycogen and Disease-Models--Animal

Glycogen phosphorylase (PG) is a key enzyme taking part in the first step of glycogenolysis. Muscle glycogen phosphorylase (PYGM) differs from other PG isoforms in expression pattern and biochemical properties. The main role of PYGM is providing sufficient energy for muscle contraction. However, it is expressed in tissues other than muscle, such as the brain, lymphoid tissues, and blood. PYGM is important not only in glycogen metabolism, but also in such diverse processes as the insulin and glucagon signaling pathway, insulin resistance, necroptosis, immune response, and phototransduction. PYGM is implicated in several pathological states, such as muscle glycogen phosphorylase deficiency (McArdle disease), schizophrenia, and cancer. Here we attempt to analyze the available data regarding the protein partners of PYGM to shed light on its possible interactions and functions. We also underline the potential for zebrafish to become a convenient and applicable model to study PYGM functions, especially because of its unique features that can complement data obtained from other approaches.

Topics: Animals; Disease Models, Animal; Gene Expression Regulation; Glycogen; Glycogen Phosphorylase; Glycogen Storage Disease Type V; Humans; Insulin Resistance; Light Signal Transduction; Muscle Contraction; Muscle, Skeletal; Necroptosis; Neoplasms; Protein Interaction Mapping; Retinal Pigment Epithelium; Schizophrenia; Zebrafish

The placenta performs a range of crucial functions that support fetal growth during pregnancy, including facilitating the supply of oxygen and nutrients to the fetus, removal of waste products from the fetus and the endocrine modulation of maternal physiology. The placenta also stores glucose in the form of glycogen, the function of which remains unknown. Aberrant placental glycogen storage in humans is associated with maternal diabetes during pregnancy and pre-eclampsia, thus linking placental glycogen storage and metabolism to pathological pregnancies. To understand the role of placental glycogen in normal and complicated pregnancies, we must turn to animal models. Over 40 targeted mutations in mice demonstrate the defects in placental cells that store glycogen and suggest that placental glycogen represents a source of readily mobilized glucose required during periods of high fetal demand. However, direct functional evidence is currently lacking. Here, we evaluate these genetic mouse models with placental phenotypes that implicate glycogen trophoblast cell differentiation and function to illuminate the common molecular pathways that emerge and to better understand the relationship between placental glycogen and fetal growth. We highlight the current limitations in exploring the key questions regarding placental glycogen storage and metabolism and define how to experimentally overcome these constraints.

Topics: Animals; Disease Models, Animal; Female; Fetal Development; Glycogen; Mice; Mutation; Placenta; Placenta Diseases; Pregnancy

GSD are a group of disorders characterized by a defect in gene expression of specific enzymes involved in glycogen breakdown or synthesis, commonly resulting in the accumulation of glycogen in various tissues (primarily the liver and skeletal muscle). Several different GSD animal models have been found to naturally present spontaneous mutations and others have been developed and characterized in order to further understand the physiopathology of these diseases and as a useful tool to evaluate potential therapeutic strategies. In the present work we have reviewed a total of 42 different animal models of GSD, including 26 genetically modified mouse models, 15 naturally occurring models (encompassing quails, cats, dogs, sheep, cattle and horses), and one genetically modified zebrafish model. To our knowledge, this is the most complete list of GSD animal models ever reviewed. Importantly, when all these animal models are analyzed together, we can observe some common traits, as well as model specific differences, that would be overlooked if each model was only studied in the context of a given GSD.

Topics: Animals; Animals, Genetically Modified; Cats; Cattle; Disease Models, Animal; Dogs; Glycogen; Glycogen Storage Disease; Horses; Humans; Liver; Mice; Muscle, Skeletal; Quail; Sheep; Zebrafish

Glycogen storage diseases (GSDs) type I (GSDI) and type III (GSDIII), the most frequent hepatic GSDs, are due to defects in glycogen metabolism, mainly in the liver. In addition to hypoglycemia and liver pathology, renal, myeloid, or muscle complications affect GSDI and GSDIII patients. Currently, patient management is based on dietary treatment preventing severe hypoglycemia and increasing the lifespan of patients. However, most of the patients develop long-term pathologies. In the past years, gene therapy for GSDI has generated proof of concept for hepatic GSDs. This resulted in a recent clinical trial of adeno-associated virus (AAV)-based gene replacement for GSDIa. However, the current limitations of AAV-mediated gene transfer still represent a challenge for successful gene therapy in GSDI and GSDIII. Indeed, transgene loss over time was observed in GSDI liver, possibly due to the degeneration of hepatocytes underlying the physiopathology of both GSDI and GSDIII and leading to hepatic tumor development. Moreover, multitissue targeting requires high vector doses to target nonpermissive tissues such as muscle and kidney. Interestingly, recent pharmacological interventions or dietary regimen aiming at the amelioration of the hepatocyte abnormalities before the administration of gene therapy demonstrated improved efficacy in GSDs. In this review, we describe the advances in gene therapy and the limitations to be overcome to achieve efficient and safe gene transfer in GSDs.

Topics: Animals; Clinical Trials as Topic; Dependovirus; Disease Models, Animal; Gene Transfer Techniques; Genetic Therapy; Genetic Vectors; Glucose-6-Phosphatase; Glycogen; Glycogen Storage Disease Type I; Glycogen Storage Disease Type III; Hepatocytes; Humans; Hypoglycemia; Liver; Transgenes

Lafora disease (LD) is a fatal, autosomal recessive, glycogen-storage disorder that manifests as severe epilepsy. LD results from mutations in the gene encoding either the glycogen phosphatase laforin or the E3 ubiquitin ligase malin. Individuals with LD develop cytoplasmic, aberrant glycogen inclusions in nearly all tissues that more closely resemble plant starch than human glycogen. This Minireview discusses the unique window into glycogen metabolism that LD research offers. It also highlights recent discoveries, including that glycogen contains covalently bound phosphate and that neurons synthesize glycogen and express both glycogen synthase and glycogen phosphorylase.

Topics: Animals; Carbohydrate Conformation; Carrier Proteins; Disease Models, Animal; Glycogen; Glycogen Phosphorylase; Humans; Lafora Disease; Neurons; Phosphates; Phosphorylation; Protein Tyrosine Phosphatases, Non-Receptor; Ubiquitin-Protein Ligases

Lafora disease (LD) is an autosomal recessive progressive myoclonus epilepsy due to mutations in the EPM2A (laforin) and EPM2B (malin) genes, with no substantial genotype-phenotype differences between the two. Founder effects and recurrent mutations are common, and mostly isolated to specific ethnic groups and/or geographical locations. Pathologically, LD is characterized by distinctive polyglucosans, which are formations of abnormal glycogen. Polyglucosans, or Lafora bodies (LB) are typically found in the brain, periportal hepatocytes of the liver, skeletal and cardiac myocytes, and in the eccrine duct and apocrine myoepithelial cells of sweat glands. Mouse models of the disease and other naturally occurring animal models have similar pathology and phenotype. Hypotheses of LB formation remain controversial, with compelling evidence and caveats for each hypothesis. However, it is clear that the laforin and malin functions regulating glycogen structure are key. With the exception of a few missense mutations LD is clinically homogeneous, with onset in adolescence. Symptoms begin with seizures, and neurological decline follows soon after. The disease course is progressive and fatal, with death occurring within 10 years of onset. Antiepileptic drugs are mostly non-effective, with none having a major influence on the progression of cognitive and behavioral symptoms. Diagnosis and genetic counseling are important aspects of LD, and social support is essential in disease management. Future therapeutics for LD will revolve around the pathogenesics of the disease. Currently, efforts at identifying compounds or approaches to reduce brain glycogen synthesis appear to be highly promising.

Topics: Animals; Disease Models, Animal; Genetic Counseling; Glycogen; Humans; Lafora Disease; Mice; Protein Tyrosine Phosphatases, Non-Receptor

Glycogen storage disorders (GSDs) are inborn errors of metabolism with abnormal storage or utilization of glycogen. The present review focuses on recent advances in hepatic GSD types I, III and VI/IX, with emphasis on clinical aspects and treatment.. Evidence accumulates that poor metabolic control is a risk factor for the development of long-term complications, such as liver adenomas, low bone density/osteoporosis, and kidney disease in GSD I. However, mechanisms leading to these complications remain poorly understood and are being investigated. Molecular causes underlying neutropenia and neutrophil dysfunction in GSD I have been elucidated. Case series provide new insights into the natural course and outcome of GSD types VI and IX. For GSD III, a high protein/fat diet has been reported to improve (cardio)myopathy, but the beneficial effect of this dietary concept on muscle and liver disease manifestations needs to be further established in prospective studies.. Although further knowledge has been gained regarding pathophysiology, disease course, treatment, and complications of hepatic GSDs, more controlled prospective studies are needed to assess effects of different dietary and medical treatment options on long-term outcome and quality of life.

Topics: Animals; Cardiomyopathies; Diet, Carbohydrate-Restricted; Diet, High-Fat; Dietary Carbohydrates; Dietary Fats; Dietary Proteins; Disease Models, Animal; Glycogen; Glycogen Storage Disease Type I; Glycogen Storage Disease Type III; Glycogen Storage Disease Type VI; Humans; Liver; Liver Cirrhosis

McArdle disease is arguably the paradigm of exercise intolerance in humans. This disorder is caused by inherited deficiency of myophosphorylase, the enzyme isoform that initiates glycogen breakdown in skeletal muscles. Because patients are unable to obtain energy from their muscle glycogen stores, this disease provides an interesting model of study for exercise physiologists, allowing insight to be gained into the understanding of glycogen-dependent muscle functions. Of special interest in the field of muscle physiology and sports medicine are also some specific (if not unique) characteristics of this disorder, such as the so-called 'second wind' phenomenon, the frequent exercise-induced rhabdomyolysis and myoglobinuria episodes suffered by patients (with muscle damage also occurring under basal conditions), or the early appearance of fatigue and contractures, among others. In this article we review the main pathophysiological features of this disorder leading to exercise intolerance as well as the currently available therapeutic possibilities. Patients have been traditionally advised by clinicians to refrain from exercise, yet sports medicine and careful exercise prescription are their best allies at present because no effective enzyme replacement therapy is expected to be available in the near future. As of today, although unable to restore myophosphorylase deficiency, the 'simple' use of exercise as therapy seems probably more promising and practical for patients than more 'complex' medical approaches.

Topics: Animals; Disease Models, Animal; Exercise Tolerance; Glycogen; Glycogen Storage Disease Type V; Glycogen Synthase; Humans; Models, Biological; Muscle Fatigue; Muscle, Skeletal; Physical Exertion; Rhabdomyolysis; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Sports Medicine

While it has long been known that zinc (Zn) is crucial for the proper growth and maintenance of normal biological functions, Zn has also been shown to exert insulin-mimetic and anti-diabetic effects. These insulin-like properties have been demonstrated in isolated cells, tissues, and different animal models of type 1 and type 2 diabetes. Zn treatment has been found to improve carbohydrate and lipid metabolism in rodent models of diabetes. In isolated cells, it enhances glucose transport, glycogen and lipid synthesis, and inhibits gluconeogenesis and lipolysis. The molecular mechanism responsible for the insulin-like effects of Zn compounds involves the activation of several key components of the insulin signaling pathways, which include the extracellular signal-regulated kinase 1/2 (ERK1/2) and phosphatidylinositol 3-kinase (PI3-K)/protein kinase B/Akt (PKB/Akt) pathways. However, the precise molecular mechanisms by which Zn triggers the activation of these pathways remain to be clarified. In this review, we provide a brief history of zinc, and an overview of its insulin-mimetic and anti-diabetic effects, as well as the potential mechanisms by which zinc exerts these effects.

Topics: Animals; Diabetes Mellitus; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Disease Models, Animal; ErbB Receptors; Glycogen; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Lipogenesis; Receptor, IGF Type 1; Signal Transduction; Zinc; Zinc Compounds

Disorders of glycogen metabolism are inborn errors of energy homeostasis affecting primarily skeletal muscle, heart, liver, and, less frequently, the central nervous system. These rare diseases are quite variable in age of onset, symptoms, morbidity, and mortality. This review provides an update on disorders of glycogen metabolism affecting skeletal muscle exclusively or predominantly. From a pathogenetic perspective, we classify these diseases as primary, if the defective enzyme is directly involved in glycogen/glucose metabolism, or secondary, if the genetic mutation affects proteins which indirectly regulate glycogen or glucose processing. In addition to summarizing the most recent clinical reports in this field, we briefly describe animal models of human glycogen disorders. These experimental models are greatly improving the understanding of the pathogenetic mechanisms underlying the muscle degenerative process associated to these diseases and provide in vivo platforms to test new therapeutic strategies.

Topics: Animals; Disease Models, Animal; Glycogen; Glycogen Storage Disease; Humans; Lysosomal Storage Diseases; Muscular Diseases; Neuromuscular Diseases

Proinsulin C-peptide, released in equimolar amounts with insulin by pancreatic β cells, since its discovery in 1967 has been thought to be devoid of biological functions apart from correct insulin processing and formation of disulfide bonds between A and B chains. However, in the last two decades research has brought a substantial amount of data indicating a crucial role of C-peptide in regulating various processes in different types of cells and organs. C-peptide acts presumably via either G-protein-coupled receptor or directly inside the cell, after being internalized. However, a receptor binding this peptide has not been identified yet. This peptide ameliorates pathological changes induced by type 1 diabetes mellitus, including glomerular hyperfiltration, vessel endothelium inflammation and neuron demyelinization. In diabetic patients and diabetic animal models, C-peptide substitution in physiological doses improves the functional and structural properties of peripheral neurons and protects against hyperglycemia-induced apoptosis, promoting neuronal development, regeneration and cell survival. Moreover, it affects glycogen synthesis in skeletal muscles. In vitro C-peptide promotes disaggregation of insulin oligomers, thus enhancing its bioavailability and effects on metabolism. There are controversies concerning the biological action of C-peptide, particularly with respect to its effect on Na⁺/K⁺-ATPase activity. Surprisingly, the excess of circulating peptide associated with diabetes type 2 contributes to atherosclerosis development. In view of these observations, long-term, large-scale clinical investigations using C-peptide physiological doses need to be conducted in order to determine safety and health outcomes of long-term administration of C-peptide to diabetic patients.

Topics: Animals; Apoptosis; Atherosclerosis; C-Peptide; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Diabetic Neuropathies; Disease Models, Animal; Glycogen; Humans; Hyperglycemia; Muscle, Skeletal; Peripheral Nervous System

Glycogen is a polymer of glucose needed to provide for a continuous source of glucose during fasting. Glycogen synthesis and degradation are tightly controlled by complex regulatory mechanisms and any disturbance in this regulation can lead to an inadequate reservoir of glycogen or an accumulation of excess or abnormal glycogen stored either in the cytosol or in the lysosomes. Problems in the degradation or synthesis of glycogen are referred to as glycogen storage disorders (GSDs), which individually are rare diseases, yet collectively are a major category of inborn errors of metabolism in humans. To date, 11 distinct forms of GSDs are represented in animal models. These models provide a means to understand the mechanisms that regulate and execute the synthesis and degradation of glycogen. In this review, we summarize animal models that have arisen spontaneously in nature or have been engineered in the laboratory by recombinant DNA techniques, and categorize the disorders of glycogen metabolism as disorders of either synthesis or degradation.

Topics: Animals; Disease Models, Animal; Glycogen; Glycogen Storage Disease; Glycolysis; Humans

Glycogen storage diseases (GSD) affect primarily the liver, skeletal muscle, heart, and sometimes the central nervous system and the kidneys. These unique diseases are quite varied in age of onset of symptoms, morbidity, and mortality. Glycogen storage diseases are classified according to their individual enzyme deficiency. Each of these enzymes regulates synthesis or degradation of glycogen. Interestingly, there is great phenotypic variation and variable clinical courses even when a specific enzyme is altered by mutation. Depending on the specific mutation in an enzyme, a GSD patient may have a favorable or unfavorable prognosis. With neonatal or infantile forms, some GSDs lead to death within the first year of life, whereas other glycogen storage diseases are relatively asymptomatic or may cause only exercise intolerance. The paper provides a brief review and update of glycogen storage diseases, with respect to clinical features, genetic abnormalities, pathologic features, and treatment.

Topics: Animals; Disease Models, Animal; Glycogen; Glycogen Storage Disease; Hepatocytes; Humans; Infant; Infant, Newborn; Liver; Microscopy, Electron, Transmission; Prenatal Diagnosis

Seizures are the result of a sudden and temporary synchronization of neuronal activity, the reason for which is not clearly understood. Astrocytes participate in the control of neurotransmitter storage and neurotransmission efficacy. They provide fuel to neurons, which need a high level of energy to sustain normal and pathological neuronal activities, such as during epilepsy. Various genetic or induced animal models have been developed and used to study epileptogenic mechanisms. Methionine sulfoximine induces both seizures and the accumulation of brain glycogen, which might be considered as a putative energy store to neurons in various animals. Animals subjected to methionine sulfoximine develop seizures similar to the most striking form of human epilepsy, with a long pre-convulsive period of several hours, a long convulsive period during up to 48 hours and a post convulsive period during which they recover normal behavior. The accumulation of brain glycogen has been demonstrated in both the cortex and cerebellum as early as the pre-convulsive period, indicating that this accumulation is not a consequence of seizures. The accumulation results from an activation of gluconeogenesis specifically localized to astrocytes, both in vivo and in vitro. Both seizures and brain glycogen accumulation vary when using different inbred strains of mice. C57BL/6J is the most "resistant" strain to methionine sulfoximine, while CBA/J is the most "sensitive" one. The present review describes the data obtained on methionine sulfoximine dependent seizures and brain glycogen in the light of neurotransmission, highlighting the relevance of brain glycogen content in epilepsies.

Topics: Animals; Brain; Disease Models, Animal; Energy Metabolism; Epilepsy; Glycogen; Humans; Methionine Sulfoximine; Synaptic Transmission

Hepatic-directed vesicle insulin (HDV-I), a novel investigational vesicle (<150 nm diameter) insulin delivery system that carries insulin and a specific hepatocyte-targeting molecule (HTM) in its phospholipid bilayer and has the ability to mimic a portal vein insulin infusion remotely [subcutaneous (SC) HDV-I] and noninvasively (oral HDV-I), has been developed. This review summarizes formulation development, subsequent refinements, and results of preclinical evaluation studies, including biodistribution, mechanistic, and toxicology studies of predominantly SC HDV-I, in various animal models. Studies conducted to date have confirmed the hepatocyte specificity of HDV and HDV-I and revealed that HDV-I can stimulate the conversion of hepatic glucose output to uptake at a dose that is <1% of the dose of regular insulin (RI) required for liver stimulation; suggest that the enhanced antihyperglycemic effect of HDV-I is due to hepatic glucose uptake; and in pancreatectomized dogs during an oral glucose tolerance test, HDV-I normalized blood glucose curves when compared to control curves in intact dogs and prevented secondary hypoglycemia in contrast to the same dose of RI. A 28-day SC HDV toxicity study in rats revealed no clinical, clinical laboratory, or histopathological findings, and the battery of three genetic toxicology studies was negative. Results support the hypothesis that HDV-I works by stimulating hepatic glucose uptake and/or glycogen storage in insulin-deficient animals. The ability to target the delivery of HDV-I to the liver reestablishes the liver as a major metabolic modulator of glucose metabolism. The future of HDV-I depends on the results of ongoing development and longer term clinical trials.

Topics: Administration, Oral; Animals; Biological Transport; Blood Glucose; Chemistry, Pharmaceutical; Diabetes Mellitus; Disease Models, Animal; Dogs; Drug Carriers; Drug Evaluation, Preclinical; Glycogen; Humans; Hypoglycemic Agents; Injections, Subcutaneous; Insulin; Liposomes; Liver; Mice; Phospholipids; Rats

Since its discovery more than a decade ago, the Ser/Thr kinase Akt/PKB (protein kinase B) has been recognized as being remarkably well conserved across a broad range of species and involved in a diverse array of cellular processes. Among its many roles, Akt appears to be common to signaling pathways that mediate the metabolic effects of insulin in several physiologically important target tissues. Refining our understanding of those pivotal molecular components that normally coordinate insulin action throughout the body is essential for a full understanding of insulin resistance in diabetes mellitus and ultimately the successful treatment of this disease.

Topics: Adipose Tissue; Animals; Base Sequence; Diabetes Mellitus, Type 2; Disease Models, Animal; Energy Metabolism; Glucose; Glucose Transporter Type 4; Glycogen; Insulin; Lipid Metabolism; Liver; Mice; Molecular Sequence Data; Monosaccharide Transport Proteins; Muscle Proteins; Muscles; Nitric Oxide Synthase; Pancreas; Protein Biosynthesis; Protein Isoforms; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt

Topics: Animals; Chromans; Diabetes Mellitus; Disease Models, Animal; Glycogen; Glycolysis; Humans; Hypoglycemic Agents; Insulin; Islets of Langerhans; Liver; Thiazoles; Thiazolidinediones; Troglitazone

Topics: Animals; Diabetes Mellitus; Disease Models, Animal; Glycogen; Glycolysis; Hypoglycemic Agents; Insulin Resistance; Liver; Pioglitazone; Thiazoles; Thiazolidinediones

Topics: Animals; Disease Models, Animal; Glycogen; Ischemic Preconditioning, Myocardial; Myocardial Contraction; Myocardial Ischemia; Rabbits; Rats; Sodium-Hydrogen Exchangers; Swine

Topics: Animals; Animals, Newborn; Blood Glucose; Disease Models, Animal; Glucagon; Gluconeogenesis; Glycogen; Homeostasis; Humans; Infant, Newborn; Insulin; Liver; Sepsis

Topics: Animals; Blood Chemical Analysis; Disease Models, Animal; Glycogen; Humans; Hypothalamo-Hypophyseal System; Lipolysis; Liver Glycogen; Muscles; Pituitary-Adrenal System; Proteins; Sepsis; Wounds and Injuries

Topics: Adrenocorticotropic Hormone; Animals; Blood Pressure; Chronic Disease; Disease Models, Animal; Epinephrine; Fatty Acids, Nonesterified; Female; Fetal Heart; Fetal Hypoxia; Glucagon; Glycogen; Heart Rate; Lactates; Norepinephrine; Pregnancy; Propranolol; Regional Blood Flow; Sheep; Vasopressins

Topics: Animals; Cats; Cattle; Disease Models, Animal; Dogs; G(M2) Ganglioside; Gangliosidoses; Gaucher Disease; Glycogen; Glycogen Storage Disease Type II; Glycopeptides; Humans; Leukodystrophy, Globoid Cell; Leukodystrophy, Metachromatic; Lipidoses; Lysosomes; Mannosidases; Metabolism, Inborn Errors; Mice; Niemann-Pick Diseases; Rabbits; Sphingolipids

Topics: Amniocentesis; Animals; Carbohydrate Metabolism, Inborn Errors; Cats; Cattle; Disease Models, Animal; Dogs; Female; Glycogen; Glycogen Storage Disease; Glycolipids; Glycoproteins; Humans; Male; Mucopolysaccharidoses; Polysaccharides; Pregnancy; Prenatal Diagnosis; Rats

Topics: Animals; Aspergillus; Cell Nucleus; Disease Models, Animal; Glucosidases; Glucosyltransferases; Glycogen; Glycogen Storage Disease; Humans; Infant; Injections, Intravenous; Leukocytes; Liver; Lysosomes; Male; Mitochondria; Placenta; Rats

Topics: Adenosine Triphosphate; Animals; Cell Nucleus; Citrates; Coronary Disease; Disease Models, Animal; Dogs; Endoplasmic Reticulum; Glycogen; Heart Arrest; Hypothermia; Microscopy, Electron; Mitochondria, Muscle; Myocardium; Phosphates; Phosphocreatine; Potassium; Potassium Chloride; Procaine; Rats

Topics: Acidosis; Adipose Tissue; Animals; Animals, Laboratory; Blood Glucose; Diabetes Mellitus; Disease Models, Animal; Feeding Behavior; Glycogen; Guinea Pigs; Haplorhini; Hyperglycemia; Hyperinsulinism; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Ketone Bodies; Mice; Muscles; Obesity; Pancreas; Prediabetic State; Rats

Electron-microscope studies of experimental models of myocardial ischaemia have provided basic information on the pathogenesis of hypoxic heart injury. Correlation of ultrastructural changes with biochemical data confirms the importance of catecholamine release and ionic shifts in the early evolution of ischaemic injury. An altered cellular metabolism induced by ischaemia causes rapid depletion of glycogen and is followed quickly by alterations in the nucleus, the mitochondria and the sarcotubular system; the myofibril is the organelle most resistant to hypoxia.Postmortem autolysis mimics early ischaemic change very closely and it probably has an initial hypoxic basis. Significant hypoxic-autolytic changes may begin during the agonal state. The time elapsing and the techniques of tissue preservation are critical in determining the amount of artefact. At present it is unrealistic to expect to obtain acutely ischaemic human myocardium soon enough after death to be of value in the estimation of the degree or duration of ischaemia by electron-microscope techniques. Rapidly progressive autolytic changes preclude the meaningful morphological assessment of hypoxic change at the ultrastructural level.

Topics: Animals; Cats; Coronary Disease; Disease Models, Animal; Dogs; Glycogen; Humans; Hypoxia; Magnesium Deficiency; Microscopy, Electron; Mitochondria; Myocardium; Myofibrils; Organoids; Postmortem Changes; Rabbits; Rats

Succinate and succinate receptor 1 (SUCNR1) are linked to fibrotic remodeling in models of non-alcoholic fatty liver disease (NAFLD), but whether they have roles beyond the activation of hepatic stellate cells remains unexplored. We investigated the succinate/SUCNR1 axis in the context of NAFLD specifically in hepatocytes.. We studied the phenotype of wild-type and Sucnr1. Sucnr1 was upregulated in murine liver and primary hepatocytes in response to diet-induced NASH. Sucnr1 deficiency provoked both beneficial (reduced fibrosis and endoplasmic reticulum stress) and detrimental (exacerbated steatosis and inflammation and reduced glycogen content) effects in the liver, and disrupted glucose homeostasis. Studies in vitro revealed that hepatocyte injury increased Sucnr1 expression, which when activated improved lipid and glycogen homeostasis in damaged hepatocytes. In humans, SUCNR1 expression was a good determinant of NAFLD progression to advanced stages. In a population at risk of NAFLD, circulating succinate was elevated in patients with a fatty liver index (FLI) ≥60. Indeed, succinate had good predictive value for steatosis diagnosed by FLI, and improved the prediction of moderate/severe steatosis through biopsy when added to an FLI algorithm.. We identify hepatocytes as target cells of extracellular succinate during NAFLD progression and uncover a hitherto unknown function for SUCNR1 as a regulator of hepatocyte glucose and lipid metabolism. Our clinical data highlight the potential of succinate and hepatic SUCNR1 expression as markers to diagnose fatty liver and NASH, respectively.

Topics: Animals; Disease Models, Animal; Fibrosis; Glucose; Glycogen; Hepatocytes; Humans; Liver; Mice; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Succinates

Animal models of cirrhosis are of great interest to investigate the pathological process leading to the final stage of cirrhosis. The aim of this study was to analyze the different steps involved in the progressive development of cirrhosis using Fourier transform infrared spectral histology in 2 mouse models of cirrhosis, the STAM model of metabolic cirrhosis, and the carbon tetrachloride-induced cirrhosis model. Formalin-fixed, paraffin-embedded liver samples were obtained from 3 mice at 5 time points in each model to analyze the course of hepatic lesions up to the formation of cirrhosis. For each time point, adjacent 3-μm-thick liver sections were obtained for histologic stains and spectral histology. Fourier transform infrared acquisitions of liver sections were performed at projected pixel sizes of 25 μm × 25 μm and 6.25 μm × 6.25 μm. Spectral images were then preprocessed with an extended multiplicative signal correction and analyzed with common k-means clustering, including all stages in each model. In both models, the 2- and 4-class common k-means clustering in the 1000 to 1350 cm

Topics: Animals; Carbon Tetrachloride; Disease Models, Animal; Fourier Analysis; Glycogen; Liver Cirrhosis; Longitudinal Studies; Mice; Nucleic Acids

Patients with Lafora disease have a mutation in EPM2A or EPM2B, resulting in dysregulation of glycogen metabolism throughout the body and aberrant glycogen molecules that aggregate into Lafora bodies. Lafora bodies are particularly damaging in the brain, where the aggregation drives seizures with increasing severity and frequency, coupled with neurodegeneration. Previous work employed mouse genetic models to reduce glycogen synthesis by approximately 50%, and this strategy significantly reduced Lafora body formation and disease phenotypes. Therefore, an antisense oligonucleotide (ASO) was developed to reduce glycogen synthesis in the brain by targeting glycogen synthase 1 (Gys1). To test the distribution and efficacy of this drug, the Gys1-ASO was administered to Epm2b-/- mice via intracerebroventricular administration at 4, 7, and 10 months. The mice were then sacrificed at 13 months and their brains analyzed for Gys1 expression, glycogen aggregation, and neuronal excitability. The mice treated with Gys1-ASO exhibited decreased Gys1 protein levels, decreased glycogen aggregation, and reduced epileptiform discharges compared to untreated Epm2b-/- mice. This work provides proof of concept that a Gys1-ASO halts disease progression of EPM2B mutations of Lafora disease.

Topics: Animals; Disease Models, Animal; Glycogen; Glycogen Synthase; Humans; Lafora Disease; Mice; Mutation; Oligonucleotides, Antisense; Ubiquitin-Protein Ligases

The purpose of this study is to construct a pH and redox sensitive nanoparticle to effectively deliver ginsenoside Rh

Topics: Animals; Colitis, Ulcerative; Colon; Dextran Sulfate; Disease Models, Animal; Ginsenosides; Glycogen; Hydrogen-Ion Concentration; Nanoparticles; Oxidation-Reduction

Lafora disease (LD) is a fatal childhood-onset dementia characterized by the extensive accumulation of glycogen aggregates-the so-called Lafora Bodies (LBs)-in several organs. The accumulation of LBs in the brain underlies the neurological phenotype of the disease. LBs are composed of abnormal glycogen and various associated proteins, including p62, an autophagy adaptor that participates in the aggregation and clearance of misfolded proteins. To study the role of p62 in the formation of LBs and its participation in the pathology of LD, we generated a mouse model of the disease (malin

Topics: Animals; Disease Models, Animal; Glycogen; Inclusion Bodies; Lafora Disease; Mice; Mice, Knockout; Sequestosome-1 Protein

Adult polyglucosan body disease (APBD) and Lafora disease (LD) are autosomal recessive glycogen storage neurological disorders. APBD is caused by mutations in the glycogen branching enzyme (GBE1) gene and is characterized by progressive upper and lower motor neuron dysfunction and premature death. LD is a fatal progressive myoclonus epilepsy caused by loss of function mutations in the EPM2A or EPM2B gene. These clinically distinct neurogenetic diseases share a common pathology. This consists of time-dependent formation, precipitation, and accumulation of an abnormal form of glycogen (polyglucosan) into gradually enlarging inclusions, polyglucosan bodies (PBs) in ever-increasing numbers of neurons and astrocytes. The growth and spread of PBs are followed by astrogliosis, microgliosis, and neurodegeneration. The key defect in polyglucosans is that their glucan branches are longer than those of normal glycogen, which prevents them from remaining in solution. Since the lengths of glycogen branches are determined by the enzyme glycogen synthase, we hypothesized that downregulating this enzyme could prevent or hinder the generation of the pathogenic PBs. Here, we pursued an adeno-associated virus vector (AAV) mediated RNA-interference (RNAi) strategy. This approach resulted in approximately 15% reduction of glycogen synthase mRNA and an approximately 40% reduction of PBs across the brain in the APBD and both LD mouse models. This was accompanied by improvements in early neuroinflammatory markers of disease. This work represents proof of principle toward developing a single lifetime dose therapy for two fatal neurological diseases: APBD and LD. The approach is likely applicable to other severe and common diseases of glycogen storage.

Topics: Animals; Disease Models, Animal; Glucans; Glycogen; Glycogen Storage Disease; Glycogen Synthase; Lafora Disease; Mice; MicroRNAs; Nervous System Diseases; Neuroinflammatory Diseases

Glucose is the main brain fuel in fed conditions, while astrocytic glycogen is used as supplemental fuel when the brain is stimulated. Brain glycogen levels are decreased shortly after induced seizures in rodents, but little is known about how glycogen levels are affected interictally in chronic models of epilepsy. Reduced glutamine synthetase activity has been suggested to lead to increased brain glycogen levels in humans with chronic epilepsy. Here, we used the mouse pilocarpine model of epilepsy to investigate whether brain glycogen levels are altered, both acutely and in the chronic stage of the model. One day after pilocarpine-induced convulsive status epilepticus (CSE), glycogen levels were higher in the hippocampal formation, cerebral cortex, and cerebellum. Opposite to expected, this was accompanied by elevated glutamine synthetase activity in the hippocampus but not the cortex. Increased interictal glycogen amounts were seen in the hippocampal formation and cerebral cortex in the chronic stage of the model (21 days post-CSE), suggesting long-lasting alterations in glycogen metabolism. Glycogen solubility in the cerebral cortex was unaltered in this epilepsy mouse model. Glycogen synthase kinase 3 beta (Gsk3b) mRNA levels were reduced in the hippocampal formations of mice in the chronic stage, which may underlie the elevated brain glycogen content in this model. This is the first report of elevated interictal glycogen levels in a chronic epilepsy model. Increased glycogen amounts in the brain may influence seizure susceptibility in this model, and this warrants further investigation.

Topics: Animals; Brain; Disease Models, Animal; Epilepsy; Glutamate-Ammonia Ligase; Glycogen; Mice; Pilocarpine; Seizures; Status Epilepticus

Mutations in. We utilized an inducible mouse model of GSD1b, TM-G6PT. In proximal tubule cells, G6PT suppression stimulates the upregulation and activity of hexokinase-I, which increases availability of the reabsorbed glucose for intracellular metabolism. Dapagliflozin prevented glycogen accumulation and improved kidney morphology by promoting a metabolic switch from glycogen synthesis toward lysis and by restoring expression levels of the main proximal tubule functional markers.. We provide proof of concept for the efficacy of dapagliflozin in preserving kidney function in GSD1b mice. Our findings could represent the basis for repurposing this drug to treat patients with GSD1b.

Topics: Animals; Disease Models, Animal; Glucose; Glycogen; Glycogen Storage Disease Type I; Kidney; Kidney Tubules, Proximal; Mice; Sodium-Glucose Transporter 2

Pinus koraiensis leaf (PKL) extract exerts antihyperlipidemic, antidiabetic, and anticancer effects; however, its anti-fatigue properties have not been elucidated to date. In this study, the anti-fatigue properties of PKL were evaluated by assessing the endurance of mice by a weight-loaded forced swimming (WLFS) and rotarod (RR) tests. Subsequently, various behavioral, biochemical, and physiological parameters were measured. Treatment with PKL decreased hepatic and muscular glycogen levels in mice subjected to WLFS and RR test compared to those in acute exercise-treated (AET) mice. Additionally, plasma levels of stress-related biochemical factors (lactate, lactate dehydrogenase, aminotransferase, aspartate aminotransferase, and blood urea nitrogen) decreased significantly (P < 0.05), whereas the levels of superoxide dismutase and glutathione peroxidase increased. Furthermore, PKL potentially improved mental fatigue by decreasing corticosterone and increasing serotonin levels. PKL increased the expression of phosphorylated cyclic adenosine-3',5'-monophosphate response element-binding protein and brain-derived neurotrophic factor in the hippocampus. Collectively, the anti-fatigue effects of PKL could be explained by its antioxidant activity, mediating effects on glycogen synthesis, and control over stress. In conclusion, the findings of the present study suggest that PKL is a potential nutraceutical for improving exercise performance and alleviating fatigue.

Topics: Animals; Disease Models, Animal; Glycogen; Mice; Pinus; Plant Extracts; Superoxide Dismutase; Swimming

A diverse heterogeneity of microglial cells was previously described in Alzheimer's disease (AD) pathology, including dark microglia, a state characterized by ultrastructural markers of cellular stress. To provide novel insights into the roles of dark microglia during aging in the context of AD pathology, we performed a quantitative density and ultrastructural analysis of these cells using high-throughput scanning electron microscopy in the ventral hippocampus CA1 stratum lacunosum-moleculare of 20-month-old APP-PS1 vs C57BL/6J male mice. The density of dark microglia was significantly higher in APP-PS1 vs C57BL/6J mice, with these cells accounting for nearly half of all microglia observed near amyloid-beta (Aβ) plaques. This dark microglial state interacted more with dystrophic neurites compared to other APP-PS1 microglia and possessed glycogen granules, associated with a metabolic shift toward glycolysis, which provides the first ultrastructural evidence of their presence in microglia. Dark microglia were further observed in aging human post-mortem brain samples showing similar ultrastructural features as in mouse. Overall, our results provide a quantitative ultrastructural characterization of a microglial state associated with cellular stress (i.e., dark microglia) that is primarily restricted near Aβ plaques and dystrophic neurites. The presence of this microglial state in the aging human post-mortem brain is further revealed.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Animals; Brain; Disease Models, Animal; Glycogen; Humans; Infant; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Microglia; Plaque, Amyloid

Non-alcoholic steatohepatitis (NASH) is a chronic disease characterized by inflammation, steatosis, and liver fibrosis. The liver is particularly affected by alterations in lipid metabolism. Our aim was to evaluate the effect of β-hydroxyphosphocarnitine (β-HPC) on NASH induced in rats.. NASH was characterized by elevated triglycerides, elevated liver damage enzymes, and the presence of necrosis, inflammation, steatosis, and fibrosis. Significant amounts of glycogen were found, along with α-SMA positive cells in fibrosis areas. The over-expression of SREBP-1 in cytoplasm and nuclei was evident. Animals with NASH treated with β-HPC showed a significant reduction in inflammation, necrosis, and glycogen content in the liver. A reduction in α-SMA and SREBP-1 immunopositive cells correlated with a significant reduction in the degree of fibrosis and steatosis found in liver tissue. β-HPC reduced the levels of ALP and GGT, and significantly reduced triglyceride levels. Animals treated with β-HPC did not show any alterations in liver enzyme function.. Our research shows that β-HPC can improve liver function and morphology in the case of NASH induced in rats, suggesting β-HPC could be potentially used in the treatment of NASH.

Topics: Animals; Carnitine; Cholesterol; Diet, High-Fat; Disease Models, Animal; Fructose; Glucose; Glycogen; Inflammation; Liver; Liver Cirrhosis; Necrosis; Non-alcoholic Fatty Liver Disease; Organophosphates; Rats; Rats, Wistar; Sterol Regulatory Element Binding Protein 1; Triglycerides

Pompe disease, an autosomal recessive disorder caused by deficient lysosomal acid α-glucosidase (GAA), is characterized by accumulation of intra-lysosomal glycogen in skeletal and oftentimes cardiac muscle. The c.1935C>A (p.Asp645Glu) variant, the most frequent GAA pathogenic mutation in people of Southern Han Chinese ancestry, causes infantile-onset Pompe disease (IOPD), presenting neonatally with severe hypertrophic cardiomyopathy, profound muscle hypotonia, respiratory failure, and infantile mortality. We applied CRISPR-Cas9 homology-directed repair (HDR) using a novel dual sgRNA approach flanking the target site to generate a Gaa

Topics: alpha-Glucosidases; Animals; Cardiomyopathy, Hypertrophic; Disease Models, Animal; Glucan 1,4-alpha-Glucosidase; Glycogen; Glycogen Storage Disease Type II; Humans; Infant; Mice; Muscle, Skeletal

Glucose consumption is generally increased in tumor cells to support tumor growth. Interestingly, we report that glycogen accumulation is a key initiating oncogenic event during liver malignant transformation. We found that glucose-6-phosphatase (G6PC) catalyzing the last step of glycogenolysis is frequently downregulated to augment glucose storage in pre-malignant cells. Accumulated glycogen undergoes liquid-liquid phase separation, which results in the assembly of the Laforin-Mst1/2 complex and consequently sequesters Hippo kinases Mst1/2 in glycogen liquid droplets to relieve their inhibition on Yap. Moreover, G6PC or another glycogenolysis enzyme-liver glycogen phosphorylase (PYGL) deficiency in both human and mice results in glycogen storage disease along with liver enlargement and tumorigenesis in a Yap-dependent manner. Consistently, elimination of glycogen accumulation abrogates liver growth and cancer incidence, whereas increasing glycogen storage accelerates tumorigenesis. Thus, we concluded that cancer-initiating cells adapt a glycogen storing mode, which blocks Hippo signaling through glycogen phase separation to augment tumor incidence.

Topics: Adult; Aged; Aged, 80 and over; Animals; Carcinogenesis; Cell Line; Disease Models, Animal; Down-Regulation; Female; Gene Expression Regulation, Neoplastic; Glucose-6-Phosphatase; Glycogen; Glycogen Phosphorylase; Hepatocyte Growth Factor; Hippo Signaling Pathway; Humans; Liver; Liver Neoplasms; Male; Mice, Inbred C57BL; Mice, Knockout; Middle Aged; Neoplasm Staging; Phase Transition; Precancerous Conditions; Protein Tyrosine Phosphatases, Non-Receptor; Proto-Oncogene Proteins; Serine-Threonine Kinase 3; YAP-Signaling Proteins

Mammalian glycogen chain lengths are subject to complex regulation, including by seven proteins (protein phosphatase-1 regulatory subunit 3, PPP1R3A through PPP1R3G) that target protein phosphatase-1 (PP1) to glycogen to activate the glycogen chain-elongating enzyme glycogen synthase and inactivate the chain-shortening glycogen phosphorylase. Lafora disease is a fatal neurodegenerative epilepsy caused by aggregates of long-chained, and as a result insoluble, glycogen, termed Lafora bodies (LBs). We previously eliminated PPP1R3C from a Lafora disease mouse model and studied the effect on LB formation. In the present work, we eliminate and study the effect of absent PPP1R3D. In the interim, brain cell type levels of all PPP1R3 genes have been published, and brain cell type localization of LBs clarified. Integrating these data we find that PPP1R3C is the major isoform in most tissues including brain. In the brain, PPP1R3C is expressed at 15-fold higher levels than PPP1R3D in astrocytes, the cell type where most LBs form. PPP1R3C deficiency eliminates ~90% of brain LBs. PPP1R3D is quantitatively a minor isoform, but possesses unique MAPK, CaMK2 and 14-3-3 binding domains and appears to have an important functional niche in murine neurons and cardiomyocytes. In neurons, it is expressed equally to PPP1R3C, and its deficiency eliminates ~50% of neuronal LBs. In heart, it is expressed at 25% of PPP1R3C where its deficiency eliminates ~90% of LBs. This work studies the role of a second (PPP1R3D) of seven PP1 subunits that regulate the structure of glycogen, toward better understanding of brain glycogen metabolism generally, and in Lafora disease.

Topics: Animals; Brain; Disease Models, Animal; Female; Glycogen; Humans; Lafora Disease; Male; Mice; Mice, 129 Strain; Mice, Inbred C57BL; Mice, Knockout; Myocardium; Neurons; Protein Phosphatase 1

Lafora disease (LD) is a fatal adolescence-onset neurodegenerative condition. The hallmark of LD is the accumulation of aberrant glycogen aggregates called Lafora bodies (LBs) in the brain and other tissues. Impeding glycogen synthesis from early embryonic stages by genetic suppression of glycogen synthase (MGS) in an animal model of LD prevents LB formation and ultimately the pathological manifestations of LD thereby indicating that LBs are responsible for the pathophysiology of the disease. However, it is not clear whether eliminating glycogen synthesis in an adult animal after LBs have already formed would halt or reverse the progression of LD. Herein we generated a mouse model of LD with inducible MGS suppression. We evaluated the effect of MGS suppression at different time points on LB accumulation as well as on the appearance of neuroinflammation, a pathologic trait of LD models. In the skeletal muscle, MGS suppression in adult LD mice blocked the formation of new LBs and reduced the number of glycogen aggregates. In the brain, early but not late MGS suppression halted the accumulation of LBs. However, the neuroinflammatory response was still present, as shown by the levels of reactive astrocytes, microglia and inflammatory cytokines. Our results confirm that MGS as a promising therapeutic target for LD and highlight the importance of an early diagnosis for effective treatment of the disease.

Topics: Animals; Brain; Disease Models, Animal; Glycogen; Glycogen Synthase; Lafora Disease; Mice; Mice, Inbred C57BL; Mice, Knockout; Muscle, Skeletal

Topics: 3-Hydroxybutyric Acid; Animals; Anticholesteremic Agents; Atherosclerosis; Cholesterol; Diet, High-Fat; Disease Models, Animal; Fatty Acids; Gene Expression Profiling; Gene Expression Regulation, Enzymologic; Glucose; Glucosides; Glycogen; Hypercholesterolemia; Lipidomics; Lipogenesis; Liver; Male; Mice, Inbred C57BL; Mice, Knockout, ApoE; Phenols; Proton Magnetic Resonance Spectroscopy

Brain glycogen localized in astrocytes produces lactate via cAMP signaling, which regulates memory functions and endurance capacity. Exhaustive endurance exercise with hypoglycemia decreases brain glycogen, although the mechanism underlying this phenomenon remains unclear. Since insulin-induced hypoglycemia decreases brain glycogen, this study tested the hypothesis that hypoglycemia mediates exercise-induced brain glycogen decrease. To test the hypothesis, the effects of insulin- and exhaustive exercise-induced hypoglycemia on brain glycogen levels were compared using the microwave irradiation method in adult Wistar rats. The insulin challenge and exhaustive exercise induced similar levels of severe hypoglycemia. Glycogen in the hypothalamus and cerebellum decreased similarly with the insulin challenge and exhaustive exercise; however, glycogen in the cortex, hippocampus, and brainstem of the exercise group were lower compared with the insulin group. Brain lactate and cAMP levels in the hypothalamus and cerebellum increased similarly with the insulin challenge and exhaustive exercise, but those in the cortex, hippocampus, and brainstem of the exercise group were higher compared with the insulin group. Blood glucose correlated positively with brain glycogen, but the slope of regression lines was greater in the exercise group compared with the insulin group in the cortex, hippocampus, and brainstem, but not the hypothalamus and cerebellum. These findings support the hypothesis that hypoglycemia mediates the exercise-induced reduction in brain glycogen, at least in the hypothalamus and cerebellum. However, glycogen reduction during exhaustive endurance exercise in the cortex, hippocampus, and brainstem is not due to hypoglycemia alone, implicating the role of exercise-specific neuronal activity in brain glycogen decrease.

Topics: Animals; Blood Glucose; Brain; Cyclic AMP; Disease Models, Animal; Glycogen; Hypoglycemia; Insulin; Lactic Acid; Liver; Male; Muscle, Skeletal; Physical Endurance; Rats, Wistar; Time Factors

Stroke is the second leading cause of death and the third leading cause of disability globally. Edema is a hallmark of stroke resulting from dysregulation of water homeostasis in the central nervous system (CNS) and plays the major role in stroke-associated morbidity and mortality. The overlap between cellular and vasogenic edema makes treating this condition complicated, and to date, there is no pathogenically oriented drug treatment for edema. Water balance in the brain is tightly regulated, primarily by aquaporin 4 (AQP4) channels, which are mainly expressed in perivascular astrocytic end-feet. Targeting AQP4 could be a useful therapeutic approach for treating brain edema; however, there is no approved drug for stroke treatment that can directly block AQP4. In this study, we demonstrate that the FDA-approved drug trifluoperazine (TFP) effectively reduces cerebral edema during the early acute phase in post-stroke mice using a photothrombotic stroke model. This effect was combined with an inhibition of AQP4 expression at gene and protein levels. Importantly, TFP does not appear to induce any deleterious changes on brain electrolytes or metabolic markers, including total protein or lipid levels. Our results support a possible role for TFP in providing a beneficial extra-osmotic effect on brain energy metabolism, as indicated by the increase of glycogen levels. We propose that targeting AQP4-mediated brain edema using TFP is a viable therapeutic strategy during the early and acute phase of stroke that can be further investigated during later stages to help in developing novel CNS edema therapies.

Topics: Animals; Aquaporin 4; Biomarkers; Brain; Disease Models, Animal; Glycogen; Male; Mice; Mice, Inbred BALB C; Protein Aggregates; Stroke; Trifluoperazine

Wilson disease (WD) is caused by inactivation of the copper transporter Atp7b and copper overload in tissues. Mice with Atp7b deleted either globally (systemic inactivation) or only in hepatocyte recapitulate various aspects of human disease. However, their phenotypes vary, and neither the common response to copper overload nor factors contributing to variability are well defined. Using metabolic, histologic, and proteome analyses in three Atp7b-deficient mouse strains, we show that global inactivation of Atp7b enhances and specifically modifies the hepatocyte response to Cu overload. The loss of Atp7b only in hepatocytes dysregulates lipid and nucleic acid metabolisms and increases the abundance of respiratory chain components and redox balancing enzymes. In global knockouts, independently of their background, the metabolism of lipid, nucleic acid, and amino acids is inhibited, respiratory chain components are down-regulated, inflammatory response and regulation of chromosomal replication are enhanced. Decrease in glucokinase and lathosterol oxidase and elevation of mucin-13 and S100A10 are observed in all Atp7b mutant strains and reflect the extent of liver injury. The magnitude of proteomic changes in Atp7b

Topics: Animals; Biomarkers; Copper; Copper-Transporting ATPases; Disease Models, Animal; Gene Deletion; Glucose; Glycogen; Hepatocytes; Hepatolenticular Degeneration; Lipid Metabolism; Liver; Mice, Inbred C57BL; Mice, Knockout; Phenotype; Principal Component Analysis; Proteome; Time Factors

The hallmark of Lafora disease, a fatal neurodegenerative disorder, is the accumulation of intracellular glycogen aggregates called Lafora bodies. Until recently, it was widely believed that brain Lafora bodies were present exclusively in neurons and thus that Lafora disease pathology derived from their accumulation in this cell population. However, recent evidence indicates that Lafora bodies are also present in astrocytes. To define the role of astrocytic Lafora bodies in Lafora disease pathology, we deleted glycogen synthase specifically from astrocytes in a mouse model of the disease (malinKO). Strikingly, blocking glycogen synthesis in astrocytes-thus impeding Lafora bodies accumulation in this cell type-prevented the increase in neurodegeneration markers, autophagy impairment, and metabolic changes characteristic of the malinKO model. Conversely, mice that over-accumulate glycogen in astrocytes showed an increase in these markers. These results unveil the deleterious consequences of the deregulation of glycogen metabolism in astrocytes and change the perspective that Lafora disease is caused solely by alterations in neurons.

Topics: Animals; Astrocytes; Brain; Disease Models, Animal; Glycogen; Glycogen Synthase; Lafora Disease; Mice; Mice, Knockout; Nerve Degeneration; Neurons; Ubiquitin-Protein Ligases

Many adult and most childhood neurological diseases have a genetic basis. CRISPR/Cas9 biotechnology holds great promise in neurological therapy, pending the clearance of major delivery, efficiency, and specificity hurdles. We applied CRISPR/Cas9 genome editing in its simplest modality, namely inducing gene sequence disruption, to one adult and one pediatric disease. Adult polyglucosan body disease is a neurodegenerative disease resembling amyotrophic lateral sclerosis. Lafora disease is a severe late childhood onset progressive myoclonus epilepsy. The pathogenic insult in both is formation in the brain of glycogen with overlong branches, which precipitates and accumulates into polyglucosan bodies that drive neuroinflammation and neurodegeneration. We packaged Staphylococcus aureus Cas9 and a guide RNA targeting the glycogen synthase gene, Gys1, responsible for brain glycogen branch elongation in AAV9 virus, which we delivered by neonatal intracerebroventricular injection to one mouse model of adult polyglucosan body disease and two mouse models of Lafora disease. This resulted, in all three models, in editing of approximately 17% of Gys1 alleles and a similar extent of reduction of Gys1 mRNA across the brain. The latter led to approximately 50% reductions of GYS1 protein, abnormal glycogen accumulation, and polyglucosan bodies, as well as ameliorations of neuroinflammatory markers in all three models. Our work represents proof of principle for virally delivered CRISPR/Cas9 neurotherapeutics in an adult-onset (adult polyglucosan body) and a childhood-onset (Lafora) neurological diseases.

Topics: Animals; Brain; CRISPR-Cas Systems; Disease Models, Animal; Gene Editing; Glucans; Glycogen; Glycogen Storage Disease; Glycogen Synthase; Lafora Disease; Mice; Nervous System Diseases; Neuroinflammatory Diseases; Proof of Concept Study; RNA, Messenger

Pompe disease is a lysosomal storage disease caused by mutations within the GAA gene, which encodes acid α-glucosidase (GAA)-an enzyme necessary for lysosomal glycogen degradation. A lack of GAA results in an accumulation of glycogen in cardiac and skeletal muscle, as well as in motor neurons. The only FDA approved treatment for Pompe disease-an enzyme replacement therapy (ERT)-increases survival of patients, but has unmasked previously unrecognized clinical manifestations of Pompe disease. These clinical signs and symptoms include tracheo-bronchomalacia, vascular aneurysms, and gastro-intestinal discomfort. Together, these previously unrecognized pathologies indicate that GAA-deficiency impacts smooth muscle in addition to skeletal and cardiac muscle. Thus, we sought to characterize smooth muscle pathology in the airway, vascular, gastrointestinal, and genitourinary in the Gaa

Topics: alpha-Glucosidases; Animals; Disease Models, Animal; Enzyme Replacement Therapy; Glycogen; Glycogen Storage Disease Type II; Humans; Mice; Mice, Knockout; Muscle, Smooth

Most athletes continually endure mental and physical stress from intense exercise. Fructo-oligosaccharide (FOS) can reduce physical exhaustion, but the concrete mechanism behind it still needs further research. In this study, the effect of FOS on colonic mucosal barriers was investigated using an exercise-induced stress mouse model. Except for control individuals, mice were subject to cycles of 2-day exercise (at 20 rpm) interleaved by 5-day rest. The mice experienced a total of 6 days of exercise during the feeding period. FOS improved common indicators of exhaustion, such as glycogen storage in muscle. 16S rRNA data supported that changes in the gut microbiome were also closely related to stress status. Notably, Anaerotruncus was increased in mice under stress, while FOS facilitated the growth of Dorea, which is negatively associated with exhaustion. The RNA-seq analysis revealed that FOS could maintain the integrity of colonic epithelial barriers. For example, FOS significantly restored the expression of tight junctions (Occludin and Zonula occludens-1) in the colon, which was impaired under a stress state. Besides, the NOD-like receptor family pyrin domain containing 6 (NLRP6) inflammasome might contribute to the protection of the colonic mucosa by promoting the secretion of IL-18, Mucin2 (Muc2) and intestine lectin 1 (Itln1) in FOS-treated individuals. In short, FOS administration attenuated the damage of colonic mucosal barriers in exercise-induced stressed mice.

Topics: Animals; Colon; Cytokines; Disease Models, Animal; Fatty Acids, Volatile; Gastrointestinal Microbiome; Gene Expression Profiling; Glycogen; GPI-Linked Proteins; Inflammasomes; Interleukin-18; Intestinal Mucosa; Lectins; Male; Mice; Mice, Inbred BALB C; Mucin-2; Muscles; Occludin; Oligosaccharides; RNA, Ribosomal, 16S; Tight Junctions; Zonula Occludens-1 Protein

Many reports have been published recently confirmed the limitation of cargo molecules delivered into the heart. This failure is mostly associated with lymphatic or vascular channels washing or to the immune system recognition. Delivery of anthocyanins by encapsulation may augment it retention in the heart at early time points as the capsules are too large to wash out by lymphatic or venous channels and the physical structure of the capsule may shield the anthocyanins from immunoglobulins and cellular components of the immune system. In the current study, the cardiac dysfunction was induced by using carbon tetrachloride and then animal were treated orally by using anthocyanins incorporated into hydrogel NPs twice time /week for 4 weeks. The results showed anthocyanin loaded hydrogel NPs has ability to re-maintain the glycogen content in the liver and heart tissues of fibrotic group (13 ± 1.4 and 5 ± 0.7 μmol glucose/g tissue). Additionally, MDA and hydroxyproline were significantly reduced. PAS stain showed depletion of glycogen granules from heart tissue. It is concluded that starch based hydrogel loaded by anthocyanins can improve histological cardiac functions after their injury .

Topics: Animals; Anthocyanins; Carbon Tetrachloride; Cardiomyopathies; Cardiotoxicity; Disease Models, Animal; Drug Compounding; Fibrosis; Glycogen; Hydrogels; Liver; Mice; Myocytes, Cardiac; Nanoparticles; Starch

In Pompe disease, the deficiency of the lysosomal enzyme acid alpha-glucosidase (GAA) causes skeletal and cardiac muscle weakness, respiratory failure, and premature death. While enzyme replacement therapy using recombinant human GAA (rhGAA) can significantly improve patient outcomes, detailed disease mechanisms and incomplete therapeutic effects require further studies. Here we report a three-dimensional primary human skeletal muscle ("myobundle") model of infantile-onset Pompe disease (IOPD) that recapitulates hallmark pathological features including reduced GAA enzyme activity, elevated glycogen content and lysosome abundance, and increased sensitivity of muscle contractile function to metabolic stress. In vitro treatment of IOPD myobundles with rhGAA or adeno-associated virus (AAV)-mediated hGAA expression yields increased GAA activity and robust glycogen clearance, but no improvements in stress-induced functional deficits. We also apply RNA sequencing analysis to the quadriceps of untreated and AAV-treated GAA

Topics: alpha-Glucosidases; Animals; Dependovirus; Disease Models, Animal; Glycogen; Glycogen Storage Disease Type II; Lysosomes; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Muscle Contraction; Muscle Development; Muscle, Skeletal; Myocardium; Tissue Engineering

Topics: Animals; Cell Line, Tumor; Cytokines; Disease Models, Animal; Genetic Therapy; Glucose-6-Phosphatase; Glycogen; Glycogen Storage Disease; HeLa Cells; Humans; Liver; Male; Mice, Inbred C57BL; Mice, Knockout; Nanoparticles; RNA, Messenger; Treatment Outcome; Triglycerides

Glycosylation defects are a hallmark of many nervous system diseases. However, the molecular and metabolic basis for this pathology is not fully understood. In this study, we found that N-linked protein glycosylation in the brain is metabolically channeled to glucosamine metabolism through glycogenolysis. We discovered that glucosamine is an abundant constituent of brain glycogen, which functions as a glucosamine reservoir for multiple glycoconjugates. We demonstrated the enzymatic incorporation of glucosamine into glycogen by glycogen synthase, and the release by glycogen phosphorylase by biochemical and structural methodologies, in primary astrocytes, and in vivo by isotopic tracing and mass spectrometry. Using two mouse models of glycogen storage diseases, we showed that disruption of brain glycogen metabolism causes global decreases in free pools of UDP-N-acetylglucosamine and N-linked protein glycosylation. These findings revealed fundamental biological roles of brain glycogen in protein glycosylation with direct relevance to multiple human diseases of the central nervous system.

Topics: Animals; Brain; Cells, Cultured; Disease Models, Animal; Female; Glucosamine; Glycogen; Glycogen Synthase; Glycogenolysis; Glycosylation; Lafora Disease; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Protein Processing, Post-Translational

Liver Glycogen Storage Disease IX is a rare metabolic disorder of glycogen metabolism caused by deficiency of the phosphorylase kinase enzyme (PhK). Variants in the PHKG2 gene, encoding the liver-specific catalytic γ2 subunit of PhK, are associated with a liver GSD IX subtype known as PHKG2 GSD IX or GSD IX γ2. There is emerging evidence that patients with GSD IX γ2 can develop severe and progressive liver disease, yet research regarding the disease has been minimal to date. Here we characterize the first mouse model of liver GSD IX γ2.. A Phkg2. When compared to WT controls, KO mice demonstrated significantly decreased liver PhK enzyme activity, increased liver: body weight ratio, and increased glycogen in the liver, with no glycogen accumulation observed in the brain, quadricep, kidney, and heart. KO mice demonstrated elevated liver blood markers as well as elevated urine Glc. This study provides the first evidence of a mouse model that recapitulates the liver-specific pathology of patients with GSD IX γ2. The model will provide the first platform for further study of disease progression in GSD IX γ2 as well as for the evaluation of novel therapeutics.

Topics: Animals; Disease Models, Animal; Female; Glycogen; Glycogen Storage Disease; Liver; Liver Diseases; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Phosphorylase Kinase

Diabetic patients have an increased predisposition to thromboembolic events, in most cases originating from thrombi in the left atrial appendage (LAA). Remodeling of the LAA, which predisposes to thrombi formation, has been previously described in diabetic patients with atrial fibrillation, but whether remodeling of the LAA occurs in diabetics also in the absence of atrial fibrillation is unknown. To investigate the contribution of diabetes, as opposed to atrial fibrillation, to remodeling of the LAA, we went from humans to the animal model.. We studied by echocardiography the structure and function of the heart over multiple time points during the evolution of diabetes in the Cohen diabetic sensitive rat (CDs/y) provided diabetogenic diet over a period of 4 months; CDs/y provided regular diet and the Cohen diabetic resistant (CDr/y), which do not develop diabetes, served as controls. All animals were in sinus rhythm throughout the study period.. Compared to controls, CDs/y developed during the evolution of diabetes a greater heart mass, larger left atrial diameter, wider LAA orifice, increased LAA depth, greater end-diastolic and end-systolic diameter, and lower E/A ratio-all indicative of remodeling of the LAA and left atrium (LA), as well as the development of left ventricular diastolic dysfunction. To investigate the pathophysiology involved, we studied the histology of the hearts at the end of the study. We found in diabetic CDs/y, but not in any of the other groups, abundance of glycogen granules in the atrial appendages , atria  and ventricles, which may be of significance as glycogen granules have previously been associated with cell and organ dysfunction in the diabetic heart.. We conclude that our rodent model of diabetes, which was in sinus rhythm, reproduced structural and functional alterations previously observed in hearts of human diabetics with atrial fibrillation. Remodeling of the LAA and of the LA in our model was unrelated to atrial fibrillation and associated with accumulation of glycogen granules. We suggest that myocardial accumulation of glycogen granules is related to the development of diabetes and may play a pathophysiological role in remodeling of the LAA and LA, which predisposes to atrial fibrillation, thromboembolic events and left ventricular diastolic dysfunction in the diabetic heart.

Topics: Animals; Atrial Appendage; Atrial Function, Left; Atrial Remodeling; Diabetes Mellitus, Type 2; Diabetic Cardiomyopathies; Disease Models, Animal; Disease Progression; Echocardiography, Doppler, Color; Glycogen; Heart Rate; Male; Rats, Inbred Strains; Time Factors; Ventricular Function, Left

Hypoxia is known to be commonly present in breast tumor microenvironments. Stem-like cells that repopulate breast tumors, termed tumor-repopulating cells (TRC), thrive under hypoxic conditions, but the underlying mechanism remains unclear. Here, we show that hypoxia promotes the growth of breast TRCs through metabolic reprogramming. Hypoxia mobilized transcription factors HIF1α and FoxO1 and induced epigenetic reprogramming to upregulate cytosolic phosphoenolpyruvate carboxykinase (PCK1), a key enzyme that initiates gluconeogenesis. PCK1 subsequently triggered retrograde carbon flow from gluconeogenesis to glycogenesis, glycogenolysis, and the pentose phosphate pathway. The resultant NADPH facilitated reduced glutathione production, leading to a moderate increase of reactive oxygen species that stimulated hypoxic breast TRC growth. Notably, this metabolic mechanism was absent in differentiated breast tumor cells. Targeting PCK1 synergized with paclitaxel to reduce the growth of triple-negative breast cancer (TNBC). These findings uncover an altered glycogen metabolic program in breast cancer, providing potential metabolic strategies to target hypoxic breast TRCs and TNBC. SIGNIFICANCE: Hypoxic breast cancer cells trigger self-growth through PCK1-mediated glycogen metabolism reprogramming that leads to NADPH production to maintain a moderate ROS level.

Topics: Animals; Biomarkers; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Disease Models, Animal; Female; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Gluconeogenesis; Glycogen; Humans; Hypoxia; Immunohistochemistry; Intracellular Signaling Peptides and Proteins; Metabolic Networks and Pathways; Mice; NADP; Phosphoenolpyruvate Carboxykinase (GTP); Reactive Oxygen Species

Spexin (SPX) is a 14 aa peptide discovered in 2007 using bioinformatics methods. SPX inhibits food intake and regulates lipid, and carbohydrate metabolism. Here, we evaluate the ability of SPX at improving metabolic control and liver function in obese and type 2 diabetic animals. The effects of 30 days SPX treatment of mice with experimentally induced obesity (DIO) or type 2 diabetes (T2DM) on serum glucose and lipid levels, insulin sensitivity and hormonal profile (insulin, glucagon, adiponectin, leptin, TNF alpha, IL-6 and IL-1β) are characterized. In addition, alterations of hepatic lipid and glycogen contents are evaluated. We report that SPX decreases body weight in healthy and DIO mice, and reduces lipid content in all three animal groups. SPX improves insulin sensitivity in DIO and T2DM animals. In addition, SPX modulates hormonal and metabolic profile by regulating the concentration of adiponectin (concentration increase) and leptin (concentration decrease) in the serum blood of DIO and T2DM mice. Lastly, SPX decreases lipid content as well as IL-6 and TNF-α protein levels in liver of DIO and T2DM mice, and reduces IL-6 and TNF-alpha concentrations in the serum derived from T2DM mice. Based on our results, we conclude that SPX could be involved in the development of obesity and type 2 diabetes mellitus and it can be further evaluated as a potential target for therapy of DIO and T2DM.

Topics: Animals; Blood Glucose; Body Weight; Diabetes Mellitus, Type 2; Diet, High-Fat; Disease Models, Animal; Female; Glycogen; Insulin Resistance; Lipid Metabolism; Lipids; Liver Function Tests; Mice; Obesity; Peptide Hormones

McArdle disease is a disorder of carbohydrate metabolism that causes painful skeletal muscle cramps and skeletal muscle damage leading to transient myoglobinuria and increased risk of kidney failure. McArdle disease is caused by recessive mutations in the muscle glycogen phosphorylase (PYGM) gene leading to absence of PYGM enzyme in skeletal muscle and preventing access to energy from muscle glycogen stores. There is currently no cure for McArdle disease. Using a preclinical animal model, we aimed to identify a clinically translatable and relevant therapy for McArdle disease. We evaluated the safety and efficacy of recombinant adeno-associated virus serotype 8 (rAAV8) to treat a murine model of McArdle disease via delivery of a functional copy of the disease-causing gene, Pygm. Intraperitoneal injection of rAAV8-Pygm at post-natal day 1-3 resulted in Pygm expression at 8 weeks of age, accompanied by improved skeletal muscle architecture, reduced accumulation of glycogen and restoration of voluntary running wheel activity to wild-type levels. We did not observe any adverse reaction to the treatment at 8 weeks post-injection. Thus, we have investigated a highly promising gene therapy for McArdle disease with a clear path to the ovine large animal model endemic to Western Australia and subsequently to patients.

Topics: Animals; Disease Models, Animal; Female; Glycogen; Glycogen Phosphorylase, Muscle Form; Glycogen Storage Disease Type V; Inflammation; Male; Mice; Mice, Inbred C57BL; Muscle, Skeletal

Polytrauma, with combined traumatic brain injury (TBI) and systemic damage are common among military and civilians. However, the pathophysiology of peripheral organs following polytrauma is poorly understood. Using a rat model of TBI combined with hypoxemia and hemorrhagic shock, we studied the status of peripheral redox systems, liver glycogen content, creatinine clearance, and systemic inflammation. Male Sprague-Dawley rats were subjected to hypoxemia and hemorrhagic shock insults (HH), penetrating ballistic-like brain injury (PBBI) alone, or PBBI followed by hypoxemia and hemorrhagic shock (PHH). Sham rats received craniotomy only. Biofluids and liver, kidney, and heart tissues were collected at 1 day, 2 days, 7 days, 14 days, and 28 days post-injury (DPI). Creatinine levels were measured in both serum and urine. Glutathione levels, glycogen content, and superoxide dismutase (SOD) and cytochrome C oxidase enzyme activities were quantified in the peripheral organs. Acute inflammation marker serum amyloid A-1 (SAA-1) level was quantified using western blot analysis. Urine to serum creatinine ratio in PHH group was significantly elevated on 7-28 DPI. Polytrauma induced a delayed disruption of the hepatic GSH/GSSG ratio, which resolved within 2 weeks post-injury. A modest decrease in kidney SOD activity was observed at 2 weeks after polytrauma. However, neither PBBI alone nor polytrauma changed the mitochondrial cytochrome C oxidase activity. Hepatic glycogen levels were reduced acutely following polytrauma. Acute inflammation marker SAA-1 showed a significant increase at early time-points following both systemic and brain injury. Overall, our findings demonstrate temporal cytological/tissue level damage to the peripheral organs due to combined PBBI and systemic injury.

Topics: Animals; Cytochromes c; Disease Models, Animal; Glutathione; Glycogen; Head Injuries, Penetrating; Hypoxia; Kidney; Liver; Male; Myocardium; Rats; Rats, Sprague-Dawley; Shock, Hemorrhagic; Superoxide Dismutase

Muscle glycogen phosphorylase (PYGM) is a key enzyme in the first step of glycogenolysis. Mutation in the PYGM gene leads to autosomal recessive McArdle disease. Patients suffer from exercise intolerance with premature fatigue, muscle cramps and myalgia due to lack of available glucose in muscles. So far, no efficient treatment has been found. The zebrafish has many experimental advantages, and was successfully implemented as an animal model of human myopathies. Since zebrafish skeletal muscles share high similarity with human skeletal muscles, it is our animal of choice to investigate the impact of Pygm knockdown on skeletal muscle tissue. The two forms of the zebrafish enzyme, Pygma and Pygmb, share more than 80% amino acid sequence identity with human PYGM. We show that the Pygm level varies at both the mRNA and protein level in distinct stages of zebrafish development, which is correlated with glycogen level. The Pygm distribution in muscles varies from dispersed to highly organized at 72 hpf. The pygma and pygmb morpholino knockdown resulted in a reduced Pygm level in zebrafish morphants, which exhibited altered, disintegrated muscle structure and accumulation of glycogen granules in the subsarcolemmal region. Thus, lowering the Pygm level in zebrafish larvae leads to an elevated glycogen level and to morphological muscle changes mimicking the symptoms of human McArdle disease. The zebrafish model of this human disease might contribute to further understanding of its molecular mechanisms and to the development of appropriate treatment.

Topics: Animals; Disease Models, Animal; Gene Knockdown Techniques; Glycogen; Glycogen Phosphorylase, Muscle Form; Glycogen Storage Disease Type V; Humans; Muscle, Skeletal; Mutation; RNA, Messenger; Zebrafish

Lafora disease (LD) is a rare, fatal form of progressive myoclonus epilepsy. The molecular basis of this devastating disease is still poorly understood, and no treatment is available yet, which leads to the death of the patients around 10 years from the onset of the first symptoms. The hallmark of LD is the accumulation of insoluble glycogen-like inclusions in the brain and peripheral tissues, as a consequence of altered glycogen homeostasis. In addition, other determinants in the pathophysiology of LD have been suggested, such as proteostasis impairment, with reduction in autophagy, and oxidative stress, among others. In order to gain a general view of the genes involved in the pathophysiology of LD, in this work, we have performed RNA-Seq transcriptome analyses of whole-brain tissue from two independent mouse models of the disease, namely Epm2a-/- and Epm2b-/- mice, at different times of age. Our results provide strong evidence for three major facts: first, in both models of LD, we found a common set of upregulated genes, most of them encoding mediators of inflammatory response; second, there was a progression with the age in the appearance of these inflammatory markers, starting at 3 months of age; and third, reactive glia was responsible for the expression of these inflammatory genes. These results clearly indicate that neuroinflammation is one of the most important traits to be considered in order to fully understand the pathophysiology of LD, and define reactive glia as novel therapeutic targets in the disease.

Topics: Age Factors; Animals; Disease Models, Animal; Disease Progression; Glycogen; Inclusion Bodies; Lafora Disease; Mice, Knockout; Myoclonic Epilepsies, Progressive; Neuroglia; Oxidative Stress; Protein Tyrosine Phosphatases, Non-Receptor

Posttraumatic stress disorder (PTSD) causes mental and somatic diseases. Intermittent hypoxic conditioning (IHC) has cardio-, vaso-, and neuroprotective effects and alleviates experimental PTSD. IHC's ability to alleviate harmful PTSD effects on rat heart, liver, and brain was examined. PTSD was induced by 10-day exposure to cat urine scent (PTSD rats). Some rats were then adapted to 14-day IHC (PTSD+IHC rats), while PTSD and untreated control rats were cage rested. PTSD rats had a higher anxiety index (AI, X-maze test), than control or PTSD+IHC rats. This higher AI was associated with reduced glycogen content and histological signs of metabolic and hypoxic damage and of impaired contractility. The livers of PTSD rats had reduced glycogen content. Liver and blood alanine and aspartate aminotransferase activities of PTSD rats were significantly increased. PTSD rats had increased norepinephrine concentration and decreased monoamine oxidase A activity in cerebral cortex. The PTSD-induced elevation of carbonylated proteins and lipid peroxidation products in these organs reflects oxidative stress, a known cause of organ pathology. IHC alleviated PTSD-induced metabolic and structural injury and reduced oxidative stress. Therefore, IHC is a promising preventive treatment for PTSD-related morphological and functional damage to organs, due, in part, to IHC's reduction of oxidative stress.

Topics: Alanine Transaminase; Animals; Anxiety; Aspartate Aminotransferases; Behavior Rating Scale; Brain; Cats; Cerebral Cortex; Disease Models, Animal; Glycogen; Hypoxia; Liver; Male; Maze Learning; Monoamine Oxidase; Myocardium; Norepinephrine; Odorants; Oxidative Stress; Rats; Rats, Wistar; Stress Disorders, Post-Traumatic; Urine

Maladaptive responses to stress might play a role in the sensitivity of neurons to stress. To identify novel cellular responses to stress, we performed transcriptional analysis in acutely stressed mouse neurons, followed by functional characterization in Caenorhabditis elegans. In both contexts, we found that the gene GDPGP1/mcp-1 is down-regulated by a variety of stresses. Functionally, the enzyme GDPGP1/mcp-1 protects against stress. Knockdown of GDPGP1 in mouse neurons leads to widespread neuronal cell death. Loss of mcp-1, the single homologue of GDPGP1 in C. elegans, leads to increased degeneration of GABA neurons as well as reduced survival of animals following environmental stress. Overexpression of mcp-1 in neurons enhances survival under hypoxia and protects against neurodegeneration in a tauopathy model. GDPGP1/mcp-1 regulates neuronal glycogen levels, indicating a key role for this metabolite in neuronal stress resistance. Together, our data indicate that down-regulation of GDPGP1/mcp-1 and consequent loss of neuronal glycogen is a maladaptive response that limits neuronal stress resistance and reduces survival.

Topics: Animals; Apoptosis; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Disease Models, Animal; DNA Damage; Glucosyltransferases; Glycogen; Humans; Mice; Nerve Degeneration; Neurons

Perturbations in skeletal muscle metabolism have been reported for a variety of neuromuscular diseases. However, the role of metabolism after constriction injury to a nerve and the associated muscle atrophy is unclear. We have analyzed rat tibialis anterior (TA) four weeks after unilateral constriction injury to the sciatic nerve (DMG) and in the contralateral control leg (CTRL) (n = 7) to investigate changes of the metabolome, immunohistochemistry and protein levels. Untargeted metabolomics identified 79 polar metabolites, 27 of which were significantly altered in DMG compared to CTRL. Glucose concentrations were increased 2.6-fold in DMG, while glucose 6-phosphate (G6-P) was unchanged. Intermediates of the polyol pathway were increased in DMG, particularly fructose (1.7-fold). GLUT4 localization was scattered as opposed to clearly at the sarcolemma. Despite the altered localization, we found GLUT4 protein levels to be increased 7.8-fold while GLUT1 was decreased 1.7-fold in nerve damaged TA. PFK1 and GS levels were both decreased 2.1-fold, indicating an inability of glycolysis and glycogen synthesis to process glucose at sufficient rates. In conclusion, chronic nerve constriction causes increased GLUT4 levels in conjunction with decreased glycolytic activity and glycogen storage in skeletal muscle, resulting in accumulation of intramuscular glucose and polyol pathway intermediates.

Topics: Animals; Disease Models, Animal; Glucose; Glucose Transporter Type 1; Glucose Transporter Type 4; Glycogen; Glycolysis; Humans; Male; Metabolomics; Muscle, Skeletal; Muscular Atrophy; Peripheral Nerve Injuries; Polymers; Rats; Sciatic Nerve

Glycogen storage disease (GSD) type 1a is an inborn error of metabolism caused by defective glucose-6-phosphatase catalytic subunit (G6PC) activity. Patients with GSD 1a exhibit severe hepatomegaly due to glycogen and triglyceride (TG) accumulation in the liver. We have shown that the activity of carbohydrate response element binding protein (ChREBP), a key regulator of glycolysis and de novo lipogenesis, is increased in GSD 1a. In the current study, we assessed the contribution of ChREBP to nonalcoholic fatty liver disease (NAFLD) development in a mouse model for hepatic GSD 1a.. Liver-specific G6pc-knockout (L-G6pc. Attenuation of hepatic ChREBP induction in GSD 1a liver aggravates hepatomegaly because of further accumulation of glycogen and lipids as a result of reduced glycolysis and suppressed VLDL-TG secretion. TM6SF2, critical for VLDL formation, was identified as a ChREBP target in mouse liver. Altogether, our data show that enhanced ChREBP activity limits NAFLD development in GSD 1a by balancing hepatic TG production and secretion.

Topics: Adipose Tissue, White; Animals; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; Dependovirus; Disease Models, Animal; Gene Knockdown Techniques; Genetic Vectors; Glucose-6-Phosphatase; Glycogen; Glycogen Storage Disease Type I; Glycolysis; Hepatocytes; Humans; Lipogenesis; Lipoproteins, VLDL; Liver; Male; Mice; Mice, Knockout; Non-alcoholic Fatty Liver Disease; RNA, Small Interfering; Triglycerides

Psoriasis is a skin inflammatory disorder that affects 3% of the human population. Although several therapies based on the neutralization of proinflammatory cytokines have been used with relative success, additional treatments are required. The in silico analysis of gene expression data of psoriasis lesional skin and an analysis of vitamin B6 metabolites in the sera of psoriasis patients point to altered vitamin B6 metabolism at both local and systemic levels. Functional studies showed that vitamin B6 vitamers reduced skin neutrophil infiltration, oxidative stress and Nfkb activity in two zebrafish models of skin inflammation. Strikingly, inhibition of glycogen phosphorylase L (Pygl) and glucose-6-phosphate dehydrogenase (G6pd), two vitamin B6-regulated enzymes, alleviated oxidative-stress induced inflammation in zebrafish skin inflammation models. Despite the central role of G6pd in antioxidant defenses, the results of the study demonstrate that glycogen stores and G6pd fuel NADPH oxidase to promote skin inflammation, revealing novel targets for the treatment of skin inflammatory disorders.

Topics: Animals; Animals, Genetically Modified; Anti-Inflammatory Agents; Biopsy; Datasets as Topic; Disease Models, Animal; Gene Expression Profiling; Glucosephosphate Dehydrogenase; Glycogen; Glycogen Phosphorylase, Liver Form; HaCaT Cells; Humans; Intravital Microscopy; NADPH Oxidases; Oligonucleotide Array Sequence Analysis; Oxidative Stress; Psoriasis; Signal Transduction; Skin; Vitamin B 6; Zebrafish; Zebrafish Proteins

Flowering tops of Trifolium pratense L. (Fabaceae) are known for its traditional medicinal values. In present study, our aim was to investigate effect of standardized aqueous extract of flowering tops of Trifolium pratense L. on insulin resistance and SIRT1 expression in type 2 diabetic rats. Type 2 diabetes was induced by feeding high fat diet and administering low dose of streptozotocin. Diabetic animals were treated with standardized aqueous extract at three different doses. Parameters such as blood glucose, lipid profile, glycohemoglobin, insulin sensitivity, HOMA-IR and liver glycogen content were measured. Changes in morphology and expression of SIRT1 in pancreatic tissue were measured in histopathological and immunohistological studies. Aqueous extract treatment showed reduction in hyperglycemia and improved insulin sensitivity. Extract treatment also showed reduction in formation of glycated hemoglobin and improved liver glycogen level. Histopathological study revealed protecting effect of extract in pancreatic tissue against hyperglycemia induced damage. Treatment increased expression of SIRT1 in rat pancreatic tissue. Results indicate that the aqueous extract of Trifolium pratense had beneficial role in improving insulin sensitivity and SIRT1 expression.

Topics: Animals; Blood Glucose; Body Weight; Chromatography, High Pressure Liquid; Diabetes Mellitus, Type 2; Diet, High-Fat; Disease Models, Animal; Flowers; Glycogen; Hyperglycemia; Isoflavones; Male; Pancreas; Plant Extracts; Protective Agents; Rats; Rats, Sprague-Dawley; Sirtuin 1; Streptozocin; Trifolium

Bronchopulmonary dysplasia (BPD) is a major cause of mortality and morbidity in premature infants, characterized by alveolar simplification, surfactant deficiency, and respiratory distress. In the present study, we have investigated the functional roles of sumoylated CCAAT/enhancer binding protein alpha (C/EBPα) in the BPD rat model. A significant increase in small ubiquitin-like modifier 1 (SUMO1) and sumoylated C/EBPα protein levels were observed in BPD rats, and the levels of the sumoylated C/EBPα were associated with the pulmonary surfactant proteins (SPs). In order to confirm the role of sumoylated C/EBPα in BPD rats, SUMO1 was knocked down by lentiviral transfection of neonatal rat lungs with SUMO1-RNAi-LV. We found that the expression of C/EBPα and surfactant proteins increased following SUMO1 knockdown. Furthermore, the relatively low decrease in the levels of C/EBPα sumoylation was correlated with reduced glycogen consumption. Besides, co-immunoprecipitation assays revealed that sumoylation is involved in the regulation of the interaction between C/EBPα and TGFβ2 in the lung. In conclusion, our findings indicate that sumoylation may act as a negative regulator of the C/EBPα-mediated transactivation in BPD rats.

Topics: Animals; Bronchopulmonary Dysplasia; CCAAT-Enhancer-Binding Protein-alpha; Cell Differentiation; Disease Models, Animal; Gene Knockdown Techniques; Glycogen; Lung; Protein Binding; Pulmonary Surfactant-Associated Proteins; Rats, Sprague-Dawley; SUMO-1 Protein; Sumoylation; Transforming Growth Factor beta2

The ability to switch between glycolysis and ketosis promotes survival by enabling metabolism through fat oxidation during periods of fasting. Carbohydrate restriction or stress can also elicit metabolic switching. Keto-adapting from glycolysis is delayed in aged rats, but factors mediating this age-related impairment have not been identified. We measured metabolic switching between glycolysis and ketosis, as well as glycogen dynamics, in young and aged rats undergoing time-restricted feeding (TRF) with a standard diet or a low carbohydrate ketogenic diet (KD). TRF alone reversed markers of insulin-related metabolic deficits and accelerated metabolic switching in aged animals. A KD+TRF, however, provided additive benefits on these variables. Remarkably, the ability to keto-adapt was not related to glycogen levels and KD-fed rats showed an enhanced elevation in glucose following epinephrine administration. This study provides new insights into the mechanisms of keto-adaptation demonstrating the utility of dietary interventions to treat metabolic impairments across the lifespan.

Topics: Adaptation, Physiological; Aging; Animals; Blood Glucose; Diet, Ketogenic; Disease Models, Animal; Glycogen; Glycolysis; Ketosis; Male; Rats; Rats, Inbred BN; Rats, Inbred F344

While thioridazine (Tio) inhibits the antioxidant defenses of Trypanosoma cruzi, the gold standard antitrypanosomal drug benznidazole (Bz) has potent anti-inflammatory and pro-oxidant properties. The combination of these drugs has never been tested to determine the effect on T. cruzi infection. Thus, we compared the impact of Tio and Bz, administered alone and in combination, on the development of skeletal myositis and liver inflammation in T. cruzi-infected mice. Swiss mice were randomized into six groups: uninfected untreated, infected untreated, treated with Tio (80 mg/kg) alone, Bz (50 or 100 mg/kg) alone, or a combination of Tio and Bz. Infected animals were inoculated with a virulent T. cruzi strain (Y) and treated by gavage for 20 days. Mice untreated or treated with Tio alone developed the most intense parasitemia, highest parasitic load, elevated IL-10, IL-17, IFN-γ, and TNF-α plasma levels, increased N-acetylglucosaminidase and myeloperoxidase activity in the liver and skeletal muscle, as well as severe myositis and liver inflammation (P < 0.05). All parameters were markedly attenuated in animals receiving Bz alone (P < 0.05). However, the co-administration of Tio impaired the response to Bz chemotherapy, causing a decrease in parasitological control (parasitemia and parasite load), skeletal muscle and liver inflammation, and increased microstructural damage, when compared to the group receiving Bz alone (P < 0.05). Altogether, our findings indicated that Tio aggravates systemic inflammation, skeletal myositis and hepatic inflammatory damage in T. cruzi-infected mice. By antagonizing the antiparasitic potential of Bz, Tio limits the anti-inflammatory, myoprotectant and hepatoprotective effects of the reference chemotherapy, aggravating the pathological remodeling of both organs. As the interaction of T. cruzi infection, Bz and Tio is potentially toxic to the liver, inducing inflammation and microvesicular steatosis; this drug combination represents a worrying pharmacological risk factor in Chagas disease.

Topics: Acetylglucosaminidase; Animals; Chagas Disease; Cytokines; Disease Models, Animal; Drug Combinations; Female; Glycogen; Hepatitis; Mice; Muscle, Skeletal; Myositis; NADH, NADPH Oxidoreductases; Nitroimidazoles; Parasite Load; Parasitemia; Peroxidase; Thioridazine; Transaminases; Trypanocidal Agents; Trypanosoma cruzi

Pompe disease is a neuromuscular disorder caused by disease-associated variants in the gene encoding for the lysosomal enzyme acid α-glucosidase (GAA), which converts lysosomal glycogen to glucose. We previously reported full rescue of Pompe disease in symptomatic 4-month-old Gaa knockout (Gaa

Topics: alpha-Glucosidases; Animals; Dependovirus; Disease Models, Animal; Genetic Therapy; Genetic Vectors; Glycogen; Glycogen Storage Disease Type II; Liver; Lysosomes; Male; Mice; Mice, Knockout; Muscle, Skeletal; Phenotype; Secretory Pathway; Signal Transduction; Transcriptome; Transfection; Treatment Outcome

Infantile-onset Pompe Disease (IOPD), caused by mutations in lysosomal acid alpha-glucosidase (Gaa), manifests rapidly progressive fatal cardiac and skeletal myopathy incompletely attenuated by synthetic GAA intravenous infusions. The currently available murine model does not fully simulate human IOPD, displaying skeletal myopathy with late-onset hypertrophic cardiomyopathy. Bearing a Cre-LoxP induced exonic disruption of the murine Gaa gene, this model is also not amenable to genome-editing based therapeutic approaches. We report the early onset of severe hypertrophic cardiomyopathy in a novel murine IOPD model generated utilizing CRISPR-Cas9 homology-directed recombination to harbor the orthologous Gaa mutation c.1826dupA (p.Y609*), which causes human IOPD. We demonstrate the dual sgRNA approach with a single-stranded oligonucleotide donor is highly specific for the Gaa

Topics: Age of Onset; alpha-Glucosidases; Animals; Cardiomyopathy, Hypertrophic; CRISPR-Cas Systems; Disease Models, Animal; Female; Gene Knock-In Techniques; Glycogen; Glycogen Storage Disease Type II; Humans; Infant; Male; Mice; Mice, Transgenic; Muscle Weakness; Muscle, Skeletal; Myocardium; RNA, Guide, Kinetoplastida

Juvenile neuronal ceroid lipofuscinosis (JNCL, aka. juvenile Batten disease or CLN3 disease) is a lysosomal storage disease characterized by progressive blindness, seizures, cognitive and motor failures, and premature death. JNCL is caused by mutations in the Ceroid Lipofuscinosis, Neuronal 3 (CLN3) gene, whose function is unclear. Although traditionally considered a neurodegenerative disease, CLN3 disease displays eye-specific effects: Vision loss not only is often one of the earliest symptoms of JNCL, but also has been reported in non-syndromic CLN3 disease. Here we described the roles of CLN3 protein in maintaining healthy retinal pigment epithelium (RPE) and normal vision. Using electroretinogram, fundoscopy and microscopy, we showed impaired visual function, retinal autofluorescent lesions, and RPE disintegration and metaplasia/hyperplasia in a Cln3 ~ 1 kb-deletion mouse model [1] on C57BL/6J background. Utilizing a combination of biochemical analyses, RNA-Seq, Seahorse XF bioenergetic analysis, and Stable Isotope Resolved Metabolomics (SIRM), we further demonstrated that loss of CLN3 increased autophagic flux, suppressed mTORC1 and Akt activities, enhanced AMPK activity, and up-regulated gene expression of the autophagy-lysosomal system in RPE-1 cells, suggesting autophagy induction. This CLN3 deficiency induced autophagy induction coincided with decreased mitochondrial oxygen consumption, glycolysis, the tricarboxylic acid (TCA) cycle, and ATP production. We also reported for the first time that loss of CLN3 led to glycogen accumulation despite of impaired glycogen synthesis. Our comprehensive analyses shed light on how loss of CLN3 affect autophagy and metabolism. This work suggests possible links among metabolic impairment, autophagy induction and lysosomal storage, as well as between RPE atrophy/degeneration and vision loss in JNCL.

Topics: Animals; Atrophy; Autophagy; Blindness; Cell Line; Disease Models, Animal; Gene Knock-In Techniques; Gene Knockdown Techniques; Glycogen; Humans; Lysosomes; Membrane Glycoproteins; Mice; Mice, Transgenic; Microscopy, Electron; Molecular Chaperones; Mutation; Neuronal Ceroid-Lipofuscinoses; Retinal Pigment Epithelium; RNA, Small Interfering

Codonopsis pilosula is a traditional Chinese medicine and food supplement that is widely used in China. This study aimed to investigate the antifatigue and antihypoxia activities of different extracts and fractions from C. pilosula, including ethanol extract (ETH), water extract (WAT), polysaccharides (POL), inulin (INU) and oligosaccharides (OLI). Different extracts and fractions were orally administered to mice at the doses of 0.25, 0.5 and 1.0 g kg-1 once a day for 21 days. Antifatigue activity was assessed through the weight-loaded swimming test on the 21st day, and antihypoxia activity was evaluated through the normobarie hypoxia test on the following day. Finally, biochemical parameters, such as liver glycogen (LG), muscle glycogen (MG), blood urea nitrogen (BUN), lactic dehydrogenase (LDH), malondialdehyde (MDA), and glutathione (GSH) levels, were determined. The results showed that, compared with the control treatment, only POL treatment significantly prolonged the swimming time of the mice. POL groups had the strongest hypoxia tolerance, followed by the OLI and WAT groups. The levels of LG and MG were significantly increased by treatment with POL at the doses of 0.5 and 1.0 g kg-1, whereas BUN and LDH levels in POL groups were significantly lower than those in the control group. MDA under POL and OLI treatment was significantly lower than that under the control treatment. In addition, treatments with POL and OLI, except for treatment with a low dose of OLI, significantly increased GSH levels. In conclusion, POL could efficiently enhance antifatigue and antihypoxia abilities by increasing energy resources, decreasing detrimental metabolite accumulation, and enhancing antioxidant activity. OLI could improve antihypoxia activity by preventing lipid peroxidation and enhancing antioxidant activity.

Topics: Animals; Antioxidants; Body Weight; China; Codonopsis; Dietary Supplements; Disease Models, Animal; Eating; Energy Metabolism; Fatigue; Glutathione; Glycogen; Hypoxia; Lipid Peroxidation; Liver; Male; Malondialdehyde; Mice; Mice, Inbred ICR; Oligosaccharides; Plant Extracts; Polysaccharides; Swimming

Skeletal muscle glucose uptake and glucose metabolism are impaired in insulin resistance. Mechanical overload stimulates glucose uptake into insulin-resistant muscle; yet the mechanisms underlying this beneficial effect remain poorly understood. This study examined whether a differential partitioning of glucose metabolism is part of the mechanosensitive mechanism underlying overload-stimulated glucose uptake in insulin-resistant muscle. Mice were fed a high-fat diet to induce insulin resistance. Plantaris muscle overload was induced by unilateral synergist ablation. After 5 days, muscles were excised for the following measurements: (1) [

Topics: Animals; Blood Glucose; Carbohydrate Metabolism; Disease Models, Animal; Glucose; Glycogen; Glycolysis; Hexosamines; Insulin; Insulin Resistance; Male; Mice; Mice, Inbred C57BL; Muscle, Skeletal

Rheumatoid arthritis (RA) is accompanied by pain, inflammation and muscle weakness. Skeletal muscle inflammation and inactivity are independently associated with muscle insulin resistance and atrophy. Our objective was to identify early molecular and biochemical markers in muscle from a rodent model of RA relative to control and subsequently identify commonality in muscle gene expression between this model and muscle from RA patients. Pain behaviour and locomotor activity were measured in a collagen-induced arthritis (CIA) model of RA (n = 9) and control (n = 9) rats. Energy substrates and metabolites, total alkaline-soluble protein:DNA ratio and mRNA abundance of 46 targeted genes were also determined in Extensor digitorum longus muscle. Expression of targeted mRNAs was quantified in Vastus Lateralis muscle from RA patients (n = 7) and healthy age-matched control volunteers (n = 6). CIA rats exhibited pain behaviour (p<0.01) and reduced activity (p<0.05) compared to controls. Muscle glycogen content was less (p<0.05) and muscle lactate content greater (p<0.01) in CIA rats. The bioinformatics analysis of muscle mRNA abundance differences from the control, predicted the activation of muscle protein metabolism and inhibition of muscle carbohydrate and fatty acid metabolism in CIA rats. Compared to age-matched control volunteers, RA patients exhibited altered muscle mRNA expression of 8 of the transcripts included as targets in the CIA model of RA. In conclusion, muscle energy metabolism and metabolic gene expression were altered in the CIA model, which was partly corroborated by targeted muscle mRNA measurements in RA patients. This research highlights the negative impact of RA on skeletal muscle metabolic homeostasis.

Topics: Aged; Animals; Arthritis, Experimental; Arthritis, Rheumatoid; Biomarkers; Disease Models, Animal; Female; Glycogen; Humans; Inflammation; Locomotion; Middle Aged; Muscle, Skeletal; Muscular Diseases; Myalgia; Rats; Rats, Inbred Lew; RNA, Messenger; Transcriptome

Esophageal squamous cell carcinoma (ESCC) is a common gastrointestinal cancer and is often refractory to current therapies. Development of efficient therapeutic strategies against ESCC presents a major challenge. Glycogen synthase kinase (GSK)3β has emerged as a multipotent therapeutic target in various diseases including cancer. Here we investigated the biology and pathological role of GSK3β in ESCC and explored the therapeutic effects of its inhibition. The expression of GSK3β and tyrosine (Y)216 phosphorylation-dependent activity was higher in human ESCC cell lines and primary tumors than untransformed esophageal squamous TYNEK-3 cells from an ESCC patient and tumor-adjacent normal esophageal mucosa. GSK3β-specific inhibitors and small interfering (si)RNA-mediated knockdown of GSK3β attenuated tumor cell survival and proliferation, while inducing apoptosis in ESCC cells and their xenograft tumors in mice. GSK3β inhibition spared TYNEK-3 cells and the vital organs of mice. The therapeutic effect of GSK3β inhibition in tumor cells was associated with G0/G1- and G2/M-phase cell cycle arrest, decreased expression of cyclin D1 and cyclin-dependent kinase (CDK)4 and increased expression of cyclin B1. These results suggest the tumor-promoting role of GSK3β is via cyclin D1/CDK4-mediated cell cycle progression. Consequently, our study provides a biological rationale for GSK3β as a potential therapeutic target in ESCC.

Topics: Adult; Aged; Animals; Antineoplastic Agents; Apoptosis; Biomarkers, Tumor; Cell Line, Tumor; Cell Proliferation; Cell Survival; Disease Models, Animal; Esophageal Neoplasms; Esophageal Squamous Cell Carcinoma; Female; Gene Expression; Glycogen; Glycogen Synthase Kinase 3 beta; Humans; Male; Mice; Middle Aged; Molecular Targeted Therapy; Neoplasm Metastasis; Neoplasm Staging; Phosphorylation; Xenograft Model Antitumor Assays

The ribotoxin deoxynivalenol (DON) is a trichothecene found on cereals responsible for mycotoxicosis in both humans and farm animals. DON toxicity is characterized by reduced food intake, diminished nutritional efficiency and immunologic effects. The present study was designed to further characterize the alterations in energy metabolism induced by DON intoxication. We demonstrated that acute DON intoxication triggered liver steatosis associated with an altered expression of genes related to lipids oxidation, lipogenesis and lipolysis. This steatosis was concomitant to anorexia, hypoglycemia and a paradoxical transient insulin release. DON treatment resulted also in stimulation of central autonomic network regulating sympathetic outflow and adrenaline and glucocorticoids secretion. Furthermore, an increased expression of genes linked to inflammation and reticulum endoplasmic stress was observed in the liver of DON-treated mice. Finally, we propose that lipids mobilization from adipose tissues (AT) induced by DON intoxication drives hepatic steatosis since (1) genes encoding lipolytic enzymes were up-regulated in AT and (2) plasma concentration of triglycerides (TGs) and non-esterified fatty acids were increased during DON intoxication. Altogether, these data demonstrate that DON induced hormonal and metabolic dysregulations associated with a spectrum of hepatic abnormalities, evocative of a non-alcoholic fatty liver disease.

Topics: Animal Feed; Animals; Biomarkers; Cytokines; Disease Models, Animal; Endoplasmic Reticulum Stress; Energy Metabolism; Fatty Acids; Food Contamination; Glycogen; Hormones; Immunohistochemistry; Inflammation Mediators; Lipid Metabolism; Lipolysis; Liver; Male; Mice; Non-alcoholic Fatty Liver Disease; Oxidation-Reduction; Trichothecenes

Topics: Animals; Blood Glucose; Cannabidiol; Ceramides; Diet, High-Fat; Disease Models, Animal; Endocannabinoids; Glycogen; Insulin; Insulin Resistance; Male; Metabolic Networks and Pathways; Muscle, Skeletal; Obesity; Rats; Rats, Wistar; Signal Transduction; Sphingolipids

Pompe disease (PD) is caused by lysosomal glycogen accumulation in tissues, including muscles and the central nervous system (CNS). The intravenous infusion of recombinant human acid alpha-glucosidase (rhGAA) rescues the muscle pathologies in PD but does not treat the CNS because rhGAA does not cross the blood-brain barrier (BBB). To understand the CNS pathologies in PD, control and PD mice were followed and analyzed at 9 and 18 months with brain structural and ultrastructural studies. T2-weighted brain magnetic resonance imaging studies revealed the progressive dilatation of the lateral ventricles and thinning of the corpus callosum in PD mice. Electron microscopy (EM) studies at the genu of the corpus callosum revealed glycogen accumulation, an increase in nerve fiber size variation, a decrease in the g-ratio (axon diameter/total fiber diameter), and myelin sheath decompaction. The morphology of oligodendrocytes was normal. Diffusion tensor imaging (DTI) studies at the corpus callosum revealed an increase in axial diffusivity (AD) and mean diffusivity (MD) more significantly in 9-month-old PD mice. The current study suggests that axon degeneration and axon loss occur in aged PD mice and are probably caused by glycogen accumulation in neurons. A drug crossing the BBB or a treatment for directly targeting the brain might be necessary in PD.

Topics: Animals; Axons; Case-Control Studies; Corpus Callosum; Diffusion Magnetic Resonance Imaging; Diffusion Tensor Imaging; Disease Models, Animal; Female; Glycogen; Glycogen Storage Disease Type II; Humans; Male; Mice; Microscopy, Electron; Oligodendroglia

Previous studies implicate that the mitochondrial injury may play an important role in the development of post-resuscitation myocardial dysfunction, however few of them are available regarding the ultrastructural alterations of myocardial mitochondria, mitochondrial energy producing and utilization ability in the stage of arrest time (no-low) and resuscitation time (low-flow). This study aimed to observe the dynamic changes of myocardial mitochondrial function and metabolic disorders during cardiac arrest (CA) and following cardiopulmonary resuscitation (CPR).. A total of 30 healthy male Sprague-Dawley rats were randomized into three groups: 1) VF/CPR: Ventricular fibrillation (VF) was electrically induced, and 5 min of CPR was performed after 10 min of untreated VF; 2) Untreated VF: VF was induced and untreated for 15 min; and 3) Sham: Rats were identically prepared without VF/CPR. Amplitude spectrum area (AMSA) at VF 5, 10 and 15 min were calculated from ECG signals. The rats' hearts were quickly removed at the predetermined time of 15 min after beginning the procedure to gather measurements of myocardial mitochondrial function, high-energy phosphate stores, lactate, mitochondrial ultrastructure, and myocardial glycogen.. The mitochondrial respiratory control ratios significantly decreased after CA compared to sham group. CPR significantly increased respiratory control ratios compared with untreated VF animals. A significant decrease of myocardial glycogen was observed after CA, and a more rapid depletion of myocardial glycogen was observed in CPR animals. CPR significantly reduced the tissue lactate. The mitochondrial ultrastructure abnormalities in CPR animals were less severe than untreated VF animals. AMSA decayed during untreated VF; however, it was significantly greater in CPR group than the untreated VF group. In addition, AMSA was clearly positively correlated with ATP, but negatively correlated with myocardial glycogen.. Impairment of myocardial mitochondrial function and the incapability of utilizing glycogen were observed after CA. Furthermore, optimal CPR might, in part, preserved mitochondrial function and enhanced utilization of myocardial glycogen.

Topics: Animals; Cardiopulmonary Resuscitation; Disease Models, Animal; Electrocardiography; Energy Metabolism; Glycogen; Heart Arrest; Lactic Acid; Male; Mitochondria, Heart; Phosphates; Rats, Sprague-Dawley

Troxerutin (TRX) has a beneficial effect on blood viscosity and platelet aggregation, and is currently used for the treatment of chronic varicosity. Recently, TRX can improve lipid abnormalities, glucose intolerance and oxidative stress in high-fat diet-induced metabolic disorders. In this study, we tested the effect of TRX on metabolic syndrome-associated disorders using a non-obese model of metabolic syndrome-the Hereditary Hypertriglyceridaemic rats (HHTg).. Adult male HHTg rats were fed standard diet without or with TRX (150 mg/kg bwt/day for 4 weeks).. Compared to untreated rats, TRX supplementation in HHTg rats decreased serum glucose (p<0.05) and insulin (p<0.05). Although blood lipids were not affected, TRX decreased hepatic cholesterol concentrations (p<0.01) and reduced gene expression of HMGCR, SREBP2 and SCD1 (p<0.01), involved in cholesterol synthesis and lipid homeostasis. TRX-treated rats exhibited decreased lipoperoxidation and increased activity of antioxidant enzymes SOD and GPx (p<0.05) in the liver. In addition, TRX supplementation increased insulin sensitivity in muscles and epididymal adipose tissue (p<0.05). Elevated serum adiponectin (p<0.05) and decreased muscle triglyceride (p<0.05) helped improve insulin sensitivity. Among the beneficial effects of TRX were changes to cytochrome P450 family enzymes. Hepatic gene expression of CYP4A1, CYP4A3 and CYP5A1 (p<0.01) decreased, while there was a marked elevation in gene expression of CYP1A1 (p<0.01).. Our results indicate that TRX improves hepatic lipid metabolism and insulin sensitivity in peripheral tissues. As well as ameliorating oxidative stress, TRX can reduce ectopic lipid deposition, affect genes involved in lipid metabolism, and influence the activity of CYP family enzymes.

Topics: Animals; Disease Models, Animal; Glucose; Glycogen; Hydroxyethylrutoside; Hypolipidemic Agents; Insulin Resistance; Lipid Metabolism; Male; Metabolic Syndrome; Muscle, Skeletal; Oxidative Stress; Rats; Rats, Inbred Strains; Real-Time Polymerase Chain Reaction; Transcriptome

Type 2 diabetes (T2D) has become a major health problem worldwide. Skeletal muscle (SKM) is the key tissue for whole-body glucose disposal and utilization. New drugs aimed at improving insulin sensitivity of SKM would greatly expand available therapeutic options. β-arrestin-1 and -2 (Barr1 and Barr2, respectively) are two intracellular proteins best known for their ability to mediate the desensitization and internalization of G protein-coupled receptors (GPCRs). Recent studies suggest that Barr1 and Barr2 regulate several important metabolic functions including insulin release and hepatic glucose production. Since SKM expresses many GPCRs, including the metabolically important β2-adrenergic receptor, the goal of this study was to examine the potential roles of Barr1 and Barr2 in regulating SKM and whole-body glucose metabolism. Using SKM-specific knockout (KO) mouse lines, we showed that the loss of SKM Barr2, but not of SKM Barr1, resulted in mild improvements in glucose tolerance in diet-induced obese mice. SKM-specific Barr1- and Barr2-KO mice did not show any significant differences in exercise performance. However, lack of SKM Barr2 led to increased glycogen breakdown following a treadmill exercise challenge. Interestingly, mice that lacked both Barr1 and Barr2 in SKM showed no significant metabolic phenotypes. Thus, somewhat surprisingly, our data indicate that SKM β-arrestins play only rather subtle roles (SKM Barr2) in regulating whole-body glucose homeostasis and SKM insulin sensitivity.

Topics: Animals; beta-Arrestin 1; beta-Arrestin 2; Diabetes Mellitus, Type 2; Diet, High-Fat; Disease Models, Animal; Glucose; Glucose Clamp Technique; Glycogen; Humans; Insulin; Insulin Resistance; Male; Mice; Mice, Knockout; Muscle, Skeletal; Obesity; Signal Transduction

Animal models are useful for investigating the genesis of pelvic floor dysfunction and for developing novel therapies for its treatment. There is a need for an alternative large-animal model to the nonhuman primate. Therefore we studied the effects of the first vaginal delivery, ovariectomy and systemic hormonal replacement therapy (HRT) on the biomechanical and structural properties of the ovine vagina.. We examined the gross anatomical properties of nulliparous, primiparous, ovariectomized multiparous, and ovariectomized hormone-replaced multiparous sheep (six animals per group). We also harvested mid-vaginal and distal vaginal tissue to determine smooth muscle contractility and passive biomechanical properties, for morphometric assessment of the vaginal wall layers, to determine collagen and elastin content, and for immunostaining for α-smooth muscle actin and estrogen receptor-α.. There were no regional differences in the nulliparous vagina. One year after the first vaginal delivery, stiffness and contractility of the distal vagina were decreased, whereas the elastin content increased. The mid-vagina of ovariectomized sheep was stiff, and its epithelium was thin and lacked glycogen. HRT decreased the stiffness of the mid-vagina by 45% but had no measurable effect on contractility or elastin content, and increased epithelial thickness and glycogen content. HRT also increased the epithelial thickness and glycogen content of the distal vagina. At this location, there were no changes in morphology or stiffness.. In sheep, life events including delivery and ovariectomy affect the biomechanical properties of the vagina in a region-specific way. Vaginal delivery mainly affects the distal region by decreasing stiffness and contractility. HRT can reverse the increase in stiffness of the mid-vagina observed after surgical induction of menopause. These observations are in line with scanty biomechanical measurements in comparable clinical specimens.

Topics: Actins; Animals; Biomechanical Phenomena; Collagen; Disease Models, Animal; Elastin; Epithelium; Estrogen Receptor alpha; Female; Glycogen; Hormone Replacement Therapy; Muscle Contraction; Muscle, Smooth; Ovariectomy; Parity; Parturition; Pelvic Floor Disorders; Sheep; Vagina

Glucose-6-phosphatase α (G6Pase) deficiency, also known as von Gierke's Disease or Glycogen storage disease type Ia (GSD Ia), is characterized by decreased ability of the liver to convert glucose-6-phosphate to glucose leading to glycogen accumulation and hepatosteatosis. Long-term complications of GSD Ia include hepatic adenomas and carcinomas, in association with the suppression of autophagy in the liver. The G6pc-/- mouse and canine models for GSD Ia were treated with the pan-peroxisomal proliferator-activated receptor agonist, bezafibrate, to determine the drug's effect on liver metabolism and function. Hepatic glycogen and triglyceride concentrations were measured and western blotting was performed to investigate pathways affected by the treatment. Bezafibrate decreased liver triglyceride and glycogen concentrations and partially reversed the autophagy defect previously demonstrated in GSD Ia models. Changes in medium-chain acyl-CoA dehydrogenase expression and acylcarnintine flux suggested that fatty acid oxidation was increased and fatty acid synthase expression associated with lipogenesis was decreased in G6pc-/- mice treated with bezafibrate. In summary, bezafibrate induced autophagy in the liver while increasing fatty acid oxidation and decreasing lipogenesis in G6pc-/- mice. It represents a potential therapy for glycogen overload and hepatosteatosis associated with GSD Ia, with beneficial effects that have implications for non-alcoholic fatty liver disease.

Topics: Animals; Autophagy; Bezafibrate; Disease Models, Animal; Dogs; Glucose; Glucose-6-Phosphatase; Glucose-6-Phosphate; Glycogen; Glycogen Storage Disease Type I; Lipid Metabolism; Liver; Mice; Mice, Knockout; Triglycerides

Bscl2

Topics: Animals; Disease Models, Animal; Female; Gene Knockout Techniques; Glucose; Glycogen; GTP-Binding Protein gamma Subunits; Heterotrimeric GTP-Binding Proteins; Insulin Resistance; Lipid Metabolism; Lipodystrophy, Congenital Generalized; Male; Mice; Muscle, Skeletal; Organ Specificity; Oxidation-Reduction; Triglycerides

The miR-181 family plays an important role in the regulation of various cellular functions. However, whether miR-181b-5p mediates hepatic insulin resistance remains unknown. In this study, we investigated the effect of miR-181b-5p on the regulation of hepatic glycogen synthesis.. The miR-181b-5p levels in the livers of diabetic mice were detected by real-time PCR. The glycogen levels and AKT/GSK pathway activation were examined in human hepatic L02 cells and HepG2 cells transfected with miR-181b-5p mimic or inhibitor. The potential target genes of miR-181b-5p were evaluated using a luciferase reporter assay and Western blot analysis. EGR1-specific siRNA and pCMV-EGR1 were used to further determine the role of miR-181b-5p in hepatic glycogen synthesis in vitro. Hepatic inhibition of miR-181b-5p in mice was performed using adeno-associated virus 8 (AAV8) vectors by tail intravenous injection.. The miR-181b-5p levels were significantly decreased in the serum and livers of diabetic mice as well as the serum of type 2 diabetes patients. Importantly, inhibition of miR-181b-5p expression impaired the AKT/GSK pathway and reduced glycogenesis in hepatocytes. Moreover, upregulation of miR-181b-5p reversed high-glucose-induced suppression of glycogenesis. Further analysis revealed that early growth response 1 (EGR1) was a downstream target of miR-181b-5p. Silencing of EGR1 expression rescued miR-181b-5p inhibition-reduced AKT/GSK pathway activation and glycogenesis in hepatocytes. Hepatic inhibition of miR-181b-5p led to insulin resistance in C57BL/6 J mice.. We demonstrated that miR-181b-5p contributes to glycogen synthesis by targeting EGR1, thereby regulating PTEN expression to mediate hepatic insulin resistance.

Topics: Adult; Animals; Diabetes Mellitus, Type 2; Disease Models, Animal; Early Growth Response Protein 1; Female; Glycogen; Hep G2 Cells; Humans; Insulin Resistance; Liver; Male; Mice, Inbred C57BL; MicroRNAs; Middle Aged; PTEN Phosphohydrolase; Signal Transduction

The failure to maintain the viability of ischemic myocardium is one of the mechanisms that causes ischemic heart dysfunction after revascularization. Hibernating myocardium is considered to be able to maintain long-term viability during chronic hypoperfusion. Pigment epithelium-derived factor (PEDF) decreases the contractility of hypoxic cardiomyocytes and protects cardiomyocytes against ischemic injury, which is strikingly similar to the pathophysiologic characteristics of hibernating myocardium. It was therefore postulated that PEDF may induce acute ischemic myocardium into a "hibernating-like" state to maintain its viability. Adult Sprague-Dawley rat models of acute myocardial infarction were surgically established. Lentiviral vectors carrying the

Topics: Animals; Biomarkers; Disease Models, Animal; Eye Proteins; Gene Expression; Genes, Reporter; Genetic Therapy; Genetic Vectors; Glycogen; Heart Function Tests; Hibernation; Lentivirus; Male; Myocardial Contraction; Myocardial Infarction; Myocardial Ischemia; Myocardium; Necrosis; Nerve Growth Factors; Positron-Emission Tomography; Rats; Rats, Sprague-Dawley; Serpins

Pompe disease is a rare inherited disorder of lysosomal glycogen metabolism due to acid α-glucosidase (GAA) deficiency. Enzyme replacement therapy (ERT) using alglucosidase alfa, a recombinant human GAA (rhGAA), is the only approved treatment for Pompe disease. Although alglucosidase alfa has provided clinical benefits, its poor targeting to key disease-relevant skeletal muscles results in suboptimal efficacy. We are developing an rhGAA, ATB200 (Amicus proprietary rhGAA), with high levels of mannose-6-phosphate that are required for efficient cellular uptake and lysosomal trafficking. When administered in combination with the pharmacological chaperone AT2221 (miglustat), which stabilizes the enzyme and improves its pharmacokinetic properties, ATB200/AT2221 was substantially more potent than alglucosidase alfa in a mouse model of Pompe disease. The new investigational therapy is more effective at reversing the primary abnormality - intralysosomal glycogen accumulation - in multiple muscles. Furthermore, unlike the current standard of care, ATB200/AT2221 dramatically reduces autophagic buildup, a major secondary defect in the diseased muscles. The reversal of lysosomal and autophagic pathologies leads to improved muscle function. These data demonstrate the superiority of ATB200/AT2221 over the currently approved ERT in the murine model.

Topics: 1-Deoxynojirimycin; alpha-Glucosidases; Animals; Disease Models, Animal; Enzyme Replacement Therapy; Female; Glycogen; Glycogen Storage Disease Type II; Humans; Lysosomes; Male; Mannosephosphates; Mice; Mice, Knockout; Muscle, Skeletal; Rats; Rats, Sprague-Dawley

Menopause is associated with changes in body composition (a decline in lean body mass and an increase in total fat mass), leading to an increased risk of metabolic syndrome, nonalcoholic fatty liver disease, and heart disease. A healthy diet to control body weight is an effective strategy for preventing and treating menopause-related metabolic syndromes. In the present study, we investigated the effect of long-term feeding of edible oils (soybean oil (SO), tea seed oil (TO), and lard oil (LO)) on female ovariectomized (OVX) mice. SO, TO, and LO comprise mainly polyunsaturated fatty acids (PUFA), monounsaturated fatty acids (MUFA), and saturated fatty acids (SFA), respectively. However, there have been quite limited studies to investigate the effects of different fatty acids (PUFA, MUFA, and SFA) on physiological adaption and metabolic homeostasis in a menopausal population. In this study, 7-week-old female Institute of Cancer Research (ICR) mice underwent either bilateral laparotomy (sham group,

Topics: Animals; Anti-Obesity Agents; Body Weight; Diet, High-Fat; Disease Models, Animal; Fatigue; Fatty Acids, Monounsaturated; Fatty Acids, Unsaturated; Glycogen; Liver; Mice; Motor Activity; Obesity; Organ Size; Plant Oils; Seeds; Tea

Osteogenesis imperfecta (OI) is a heritable connective tissue disorder that most often arises from type I collagen-COL1A1 and COL1A2-gene defects leading to skeletal fragility, short stature, blue-gray sclera, and muscle weakness. Relative to the skeletal fragility, muscle weakness is much less understood. Recent investigations into OI muscle weakness in both patients and mouse models have revealed the presence of an inherent muscle pathology. Understanding the mechanisms responsible for OI muscle weakness is critical, particularly in light of the extensive cross-talk between muscle and bone via mechanotransduction and biochemical signaling. In the following study we initially subjected WT and oim/oim mice, modeling severe human OI type III, to either weight-bearing (voluntary wheel-running) or non-weight-bearing (swimming) exercise regimens as a modality to improve muscle strength and ultimately bone strength. The oim/oim mice ran only 35% to 42% of the distance run by age- and sex-matched WT mice and exhibited little improvement with either exercise regimen. Upon further investigation, we determined that oim/oim gastrocnemius muscle exhibited severe mitochondrial dysfunction as characterized by a 52% to 65% decrease in mitochondrial respiration rates, alterations in markers of mitochondrial biogenesis, mitophagy, and the electron transport chain components, as well as decreased mitochondrial citrate synthase activity, relative to age- and sex-matched WT gastrocnemius muscle. Thus, mitochondrial dysfunction in the oim/oim mouse likely contributes to compromised muscle function and reduced physical activity levels. © 2019 American Society for Bone and Mineral Research.

Topics: Animals; Biomarkers; Bone and Bones; Disease Models, Animal; DNA, Mitochondrial; Electron Transport; Female; Glycogen; Male; Membrane Proteins; Mice, Inbred C57BL; Microtubule-Associated Proteins; Mitochondria; Mitochondrial Proteins; Mitophagy; Muscles; Organ Size; Organelle Biogenesis; Osteogenesis Imperfecta; Physical Conditioning, Animal; Swimming

The regulation of nutrient homeostasis, i.e., the ability to transition between fasted and fed states, is fundamental in maintaining health. Since food is typically consumed over limited (anabolic) periods, dietary components must be processed and stored to counterbalance the catabolic stress that occurs between meals. Herein, we contrast tissue- and pathway-specific metabolic activity in fasted and fed states. We demonstrate that knowledge of biochemical kinetics that is obtained from opposite ends of the energetic spectrum can allow mechanism-based differentiation of healthy and disease phenotypes. Rat models of type 1 and type 2 diabetes serve as case studies for probing spatial and temporal patterns of metabolic activity via [

Topics: Amino Acids; Animals; Blood Glucose; Deuterium Oxide; Diabetes Mellitus, Experimental; Disease Models, Animal; Fasting; Fatty Acids; Glycogen; Insulin; Kinetics; Lipid Metabolism; Liver; Metabolic Networks and Pathways; Metabolomics; Muscle, Skeletal; Postprandial Period; Rats; Rats, Wistar; Rats, Zucker; Spatio-Temporal Analysis

Myopia is the most common ocular disorder and is mainly caused by axial elongation of the sclera. If the stiffness of sclera increased, it can inhibit myopia progression. The aim of this study is to compare the effect of the collagen crosslinking with different types and concentrations of carbohydrates on chemical bond and ultrastructural change of rabbit sclera.. Nine New Zealand white rabbits were treated with five, sequential sub-Tenon injections of 0.15 mL solutions of ribose, sucrose, and glycogen of 0.1, 0.2 and 0.4 M concentration at the right eye over 14 days. Ten weeks after the last injection, the rabbits were sacrificed and chemical bond and ultrastructural changes were compared with those of the untreated left sclera using Raman spectroscopy, atomic force microscopy (AFM), and histology.. Raman spectroscopy of the control and cross-linked rabbit sclera tissue revealed different types of collagen interactions. Raman shift of 919 cm-1 (C-C stretching and vibration of the proline ring in collagen) was the highest in ribose, followed by sucrose and glycogen. Total energy intensity was also highest in ribose, followed by sucrose and glycogen, and showed a tendency to increase at higher concentrations. AFM revealed interlocking arrangements of collagen fibrils. The collagen fibril diameter was 105.6 ± 21.2 nm, 109.4 ± 28.8 nm, 113.1 ± 30.8 nm and 137.6 ± 25.3 nm for control group, 0.4 M glycogen, sucrose, and ribose, respectively. Histology indicated increased density of the collagen bundle and no increase in inflammatory cell recruitment compared to control at high concentrations of ribose.. Scleral crosslinking using glycation increased the scleral biomechanical rigidity and these results were particularly pronounced in ribose. Scleral crosslinking using glycation may be a promising method for inhibiting high myopia progression.

Topics: Animals; Collagen; Disease Models, Animal; Glycogen; Glycosylation; Myopia, Degenerative; Rabbits; Ribose; Sclera; Sucrose

Agriophyllum squarrosum (L.) Moq. is a traditional Mongol medicine commonly used in the treatment of diabetes.. To examine the effects of Agriophyllum squarrosum extract (ASE) on glucose metabolism in type 2 diabetic KKAy mice, and to investigate the mechanisms underlying these effects.. KKAy mice were divided into a model control group (MCG), a low-dose Agriophyllum squarrosum extract group (LASEG), a medium-dose Agriophyllum squarrosum extract group (MASEG), a high-dose Agriophyllum squarrosum extract group (HASEG), and a metformin group (MEG). Syngeneic C57BL/6 mice were used as a normal control group (NCG). Drugs were administered to all mice by gavage for 8 weeks. Random blood glucose levels were measured in the mice at baseline and after 2, 4, and 8 weeks of treatment. Glucose tolerance was measured after 6 weeks of drug administration. After 8 weeks, glycated serum proteins (GSP) and advanced glycation end-products (AGEs) in the serum of all mice were measured. Sections of mouse liver tissues were used for periodic acid-Schiff staining (PAS) and the content of hepatic glycogen was determined. Immunohistochemistry was used to determine the effects of ASE on liver phospho-insulin receptor substrate 2 (P-IRS2) protein expression. Western blotting was used to quantify the protein expression levels of phosphatidylinositol 3-kinase (PI3K), AKT, phospho-AKT (S473) (P-AKT), glycogen synthase kinase 3β (GSK3β), and glucose transporters 4 (GLUT4), while PCR was used to quantify the mRNA expression levels of insulin receptor substrate 2 (IRS2), PI3K, AKT, GSK3β, and GLUT4.. ASE treatment decreased random blood glucose levels in type 2 diabetic KKAy mice; increased glucose tolerance; decreased serum GSP and AGEs content; increased glycogen synthesis in liver tissues; upregulated the protein expression levels of PI3K, AKT, GLUT4, and P-IRS2; downregulated the protein expression level of GSK3β in liver tissues; upregulated the mRNA expression levels of IRS2, PI3K, AKT, and GLUT4; and downregulated the mRNA expression level of GSK3β in liver tissues.. ASE treatment may increase glucose metabolism in KKAy mice and improve glucose tolerance. The underlying mechanisms of the beneficial effects of ASE may be associated with the increase of glycogen synthesis, the inhibition of AGEs production, the upregulation of IRS2, PI3K, AKT, and GLUT4 protein and mRNA expression, and the downregulation of GSK3β protein and mRNA expression.

Topics: Animals; Blood Proteins; Chenopodiaceae; Diabetes Mellitus, Experimental; Disease Models, Animal; Female; Glucose; Glycation End Products, Advanced; Glycogen; Glycogen Synthase Kinase 3 beta; Insulin Receptor Substrate Proteins; Insulin Resistance; Liver; Male; Mice, Inbred C57BL; Obesity; Phosphatidylinositol 3-Kinases; Plant Extracts; Proto-Oncogene Proteins c-akt

Obesity-related insulin resistance is associated with intramyocellular lipid accumulation in skeletal muscle. We hypothesized that in contrast to current dogma, this linkage is related to an upstream mechanism that coordinately regulates both processes. We demonstrate that the muscle-enriched transcription factor MondoA is glucose/fructose responsive in human skeletal myotubes and directs the transcription of genes in cellular metabolic pathways involved in diversion of energy substrate from a catabolic fate into nutrient storage pathways including fatty acid desaturation and elongation, triacylglyeride (TAG) biosynthesis, glycogen storage, and hexosamine biosynthesis. MondoA also reduces myocyte glucose uptake by suppressing insulin signaling. Mice with muscle-specific MondoA deficiency were partially protected from insulin resistance and muscle TAG accumulation in the context of diet-induced obesity. These results identify MondoA as a nutrient-regulated transcription factor that under normal physiological conditions serves a dynamic checkpoint function to prevent excess energy substrate flux into muscle catabolic pathways when myocyte nutrient balance is positive. However, in conditions of chronic caloric excess, this mechanism becomes persistently activated leading to progressive myocyte lipid storage and insulin resistance.

Topics: Animals; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; Cell Line; Disease Models, Animal; Female; Fructose; Glucose; Glycogen; Humans; Insulin; Insulin Resistance; Intracellular Signaling Peptides and Proteins; Lipid Metabolism; Lipids; Male; Metabolic Networks and Pathways; Mice; Mice, Inbred C57BL; Mice, Knockout; Muscle Fibers, Skeletal; Muscle, Skeletal; Obesity; Signal Transduction; Transcription Factors; Transcriptome; Triglycerides

During the development of type 2 diabetes mellitus (T2DM), hyperinsulinemia is the earliest symptom. It is believed that long-term high insulin stimulation might facilitate insulin resistance in the liver, but the underlying mechanism remains unknown. Herein, we report that hyperinsulinemia could induce persistent early growth response gene-1 (Egr-1) activation in hepatocytes, which provides negative feedback inhibition of insulin sensitivity by inducing the expression of protein tyrosine phosphatase-1B (PTP1B). Deletion of Egr-1 in the liver remarkably decreases glucose production, thus improving systemic glucose tolerance and insulin sensitivity. Mechanistic analysis indicates that Egr-1 inhibits insulin receptor phosphorylation by directly activating PTP1B transcription in the liver. Our results reveal the molecular mechanism by which hyperinsulinemia accelerates insulin resistance in hepatocytes during the progression of T2DM.

Topics: Animals; Cells, Cultured; Diabetes Mellitus, Type 2; Disease Models, Animal; Early Growth Response Protein 1; Gene Knockout Techniques; Glucose; Glycogen; Hyperinsulinism; Insulin; Insulin Resistance; Liver; Male; Mice; Phosphorylation; Protein Tyrosine Phosphatase, Non-Receptor Type 1; Receptor, Insulin; Transcriptional Activation

Topics: Animals; Autophagy; Disease Models, Animal; Fatty Acids; Fatty Liver; Glucose-6-Phosphatase; Glycogen; Glycogen Storage Disease Type I; Liver; Mice; Mice, Knockout; Mitochondria, Liver; Organelle Biogenesis; Organophosphonates; Oxidation-Reduction; Thyroid Hormone Receptors beta; Triglycerides

The aim of the present study was to determine the effects of curcumin on antioxidants using a rat model of type 1 diabetes. Seven‑week‑old male Sprague‑Dawley rats were injected with Streptozotocin (STZ) intraperitoneally to induce this model, and then treated with 1.0% curcumin (weight ratio) mixed in their diet for 21 days. The present study included three groups: Control group (NC), diabetic rat model group (DC) and a curcumin treated group (Diab‑Cur). The results demonstrated that curcumin treatment markedly decreased the blood glucose levels, plasma malondialdehyde concentration and plasma activity of glutathione peroxidase (GSH‑Px) and catalase (CAT); however, it increased the plasma superoxide dismutase (SOD) and insulin levels. Curcumin treatment increased the expression of the CAT, GSH‑Px, HO‑1 and norvegicus NAD(P)H quinone dehydrogenase 1, and decreased the SOD1 expression, which, led to a diminished oxidative stress status. In addition, curcumin treatment significantly increased the protein expression of Keap1 in the Diab‑Cur group when compared with the DC group, decreased cytosolic concentrations of Nrf2 while increasing nuclear accumulation of Nrf2. The results provide evidence that oxidative stress in the STZ‑induced diabetic rat model may be attenuated by curcumin via the activation of the Keap1‑Nrf2‑ARE signaling pathway, as evidenced by a decrease in the blood glucose concentration and an increase in the transcription of several antioxidant genes.

Topics: Animals; Antioxidants; Biomarkers; Catalase; Curcumin; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 1; Disease Models, Animal; Glutathione Peroxidase; Glycogen; Liver; Male; Malondialdehyde; Oxidative Stress; Rats; Superoxide Dismutase

McArdle disease (glycogen storage disease type V) is an inborn error of skeletal muscle metabolism, which affects glycogen phosphorylase (myophosphorylase) activity leading to an inability to break down glycogen. Patients with McArdle disease are exercise intolerant, as muscle glycogen-derived glucose is unavailable during exercise. Metabolic adaptation to blocked muscle glycogenolysis occurs at rest in the McArdle mouse model, but only in highly glycolytic muscle. However, it is unknown what compensatory metabolic adaptations occur during exercise in McArdle disease.. In this study, 8-week old McArdle and wild-type mice were exercised on a treadmill until exhausted. Dissected muscles were compared with non-exercised, age-matched McArdle and wild-type mice for histology and activation and expression of proteins involved in glucose uptake and glycogenolysis.. Investigation of expression and activation of proteins involved in glycolytic flux revealed that in glycolytic, but not oxidative muscle from exercised McArdle mice, the glycolytic flux had changed compared to that in wild-type mice. Specifically, exercise triggered in glycolytic muscle a differentiated activation of insulin receptor, 5' adenosine monophosphate-activated protein kinase, Akt and hexokinase II expression, while inhibiting glycogen synthase, suggesting that the need and adapted ability to take up blood glucose and use it for metabolism or glycogen storage is different among the investigated muscles.. The main finding of the study is that McArdle mouse muscles appear to adapt to the energy crisis by increasing expression and activation of proteins involved in blood glucose metabolism in response to exercise in the same directional way across the investigated muscles.

Topics: Animals; Disease Models, Animal; Glycogen; Glycogen Storage Disease Type V; Humans; Mice; Muscle, Skeletal; Physical Conditioning, Animal

Multiple metabolic pathways exhibit time-of-day-dependent rhythms that are controlled by the molecular circadian clock. We have shown that chronic alcohol is capable of altering the molecular clock and diurnal oscillations in several elements of hepatic glycogen metabolism ( 19 , 44 ). Herein, we sought to determine whether genetic disruption of the hepatocyte clock differentially impacts hepatic glycogen content in chronic alcohol-fed mice. Male hepatocyte-specific BMAL1 knockout (HBK) and littermate controls were fed control or alcohol-containing diets for 5 wk to alter hepatic glycogen content. Glycogen displayed a significant diurnal rhythm in livers of control genotype mice fed the control diet. While rhythmic, alcohol significantly altered the diurnal oscillation of glycogen in livers of control genotype mice. The glycogen rhythm was mildly altered in livers of control-fed HBK mice. Importantly, glycogen content was arrhythmic in livers of alcohol-fed HBK mice. Consistent with these changes in hepatic glycogen content, we observed that some glycogen and glucose metabolism genes were differentially altered by chronic alcohol consumption in livers of HBK and littermate control mice. Diurnal rhythms in glycogen synthase (mRNA and protein) were significantly altered by alcohol feeding and clock disruption. Alcohol consumption significantly altered Gck, Glut2, and Ppp1r3g rhythms in livers of control genotype mice, with diurnal rhythms of Pklr, Glut2, Ppp1r3c, and Ppp1r3g further disrupted (dampened or arrhythmic) in livers of HBK mice. Taken together, these findings show that chronic alcohol consumption and hepatocyte clock disruption differentially influence the diurnal rhythm of glycogen and various key glycogen metabolism-related genes in the liver. NEW & NOTEWORTHY We report that circadian clock disruption exacerbates alcohol-mediated alterations in hepatic glycogen. We observed differential responsiveness in diurnal rhythms of glycogen and glycogen metabolism genes and proteins in livers of hepatocyte-specific BMAL1 knockout and littermate control mice fed alcohol. Our findings provide new insights into potential mechanisms by which alcohol alters glycogen, an important energy source for liver and other organs.

Topics: Alcohol Drinking; Animals; ARNTL Transcription Factors; Circadian Rhythm; Disease Models, Animal; Gene Deletion; Gene Expression Regulation; Genotype; Glucose; Glycogen; Hepatocytes; Liver; Liver Diseases, Alcoholic; Male; Mice, Knockout; Phenotype; Time Factors

Although they are unable to utilize muscle glycogen, McArdle mice adapt favourably to an individualized moderate-intensity endurance exercise training regime. Yet, they fail to reach the performance capacity of healthy mice with normal glycogen availability. There is a remarkable difference in the protein networks involved in muscle tissue adaptations to endurance exercise training in mice with and without glycogen availability. Indeed, endurance exercise training promoted the expression of only three proteins common to both McArdle and wild-type mice: LIMCH1, PARP1 and TIGD4. In turn, trained McArdle mice presented strong expression of mitogen-activated protein kinase 12 (MAPK12).. McArdle's disease is an inborn disorder of skeletal muscle glycogen metabolism that results in blockade of glycogen breakdown due to mutations in the myophosphorylase gene. We recently developed a mouse model carrying the homozygous p.R50X common human mutation (McArdle mouse), facilitating the study of how glycogen availability affects muscle molecular adaptations to endurance exercise training. Using quantitative differential analysis by liquid chromatography with tandem mass spectrometry, we analysed the quadriceps muscle proteome of 16-week-old McArdle (n = 5) and wild-type (WT) (n = 4) mice previously subjected to 8 weeks' moderate-intensity treadmill training or to an equivalent control (no training) period. Protein networks enriched within the differentially expressed proteins with training in WT and McArdle mice were assessed by hypergeometric enrichment analysis. Whereas endurance exercise training improved the estimated maximal aerobic capacity of both WT and McArdle mice as compared with controls, it was ∼50% lower than normal in McArdle mice before and after training. We found a remarkable difference in the protein networks involved in muscle tissue adaptations induced by endurance exercise training with and without glycogen availability, and training induced the expression of only three proteins common to McArdle and WT mice: LIM and calponin homology domains-containing protein 1 (LIMCH1), poly (ADP-ribose) polymerase 1 (PARP1 - although the training effect was more marked in McArdle mice), and tigger transposable element derived 4 (TIGD4). Trained McArdle mice presented strong expression of mitogen-activated protein kinase 12 (MAPK12). Through an in-depth proteomic analysis, we provide mechanistic insight into how glycogen availability affects muscle protein signalling adaptations to endurance exercise training.

Topics: Animals; Disease Models, Animal; Exercise Tolerance; Glycogen; Glycogen Storage Disease Type V; Male; Mice; Mice, Inbred C57BL; Muscle Proteins; Muscle, Skeletal; Physical Conditioning, Animal; Protein Interaction Maps; Proteomics

Glycogen storage disease type III (GSDIII) is an autosomal recessive disorder caused by a deficiency of glycogen-debranching enzyme (GDE), which results in profound liver metabolism impairment and muscle weakness. To date, no cure is available for GSDIII and current treatments are mostly based on diet. Here we describe the development of a mouse model of GSDIII, which faithfully recapitulates the main features of the human condition. We used this model to develop and test novel therapies based on adeno-associated virus (AAV) vector-mediated gene transfer. First, we showed that overexpression of the lysosomal enzyme alpha-acid glucosidase (GAA) with an AAV vector led to a decrease in liver glycogen content but failed to reverse the disease phenotype. Using dual overlapping AAV vectors expressing the GDE transgene in muscle, we showed functional rescue with no impact on glucose metabolism. Liver expression of GDE, conversely, had a direct impact on blood glucose levels. These results provide proof of concept of correction of GSDIII with AAV vectors, and they indicate that restoration of the enzyme deficiency in muscle and liver is necessary to address both the metabolic and neuromuscular manifestations of the disease.

Topics: Animals; Biomarkers; Blood Glucose; Dependovirus; Disease Models, Animal; Enzyme Activation; Gene Expression; Gene Transfer Techniques; Genetic Therapy; Genetic Vectors; Glycogen; Glycogen Debranching Enzyme System; Glycogen Storage Disease Type III; Hepatocytes; Liver; Male; Mice; Mice, Knockout; Muscle, Skeletal; Organ Specificity; Phenotype

Lafora disease (LD) is a fatal form of progressive myoclonus epilepsy characterized by the accumulation of insoluble poorly branched glycogen-like inclusions named Lafora bodies (LBs) in the brain and peripheral tissues. In the brain, since its first discovery in 1911, it was assumed that these glycogen inclusions were only present in affected neurons. Mouse models of LD have been obtained recently, and we and others have been able to report the accumulation of glycogen inclusions in the brain of LD animals, what recapitulates the hallmark of the disease. In this work we present evidence indicating that, although in mouse models of LD glycogen inclusions co-localize with neurons, as originally established, most of them co-localize with astrocytic markers such as glial fibrillary acidic protein (GFAP) and glutamine synthase. In addition, we have observed that primary cultures of astrocytes from LD mouse models accumulate higher levels of glycogen than controls. These results suggest that astrocytes may play a crucial role in the pathophysiology of Lafora disease, as the accumulation of glycogen inclusions in these cells may affect their regular functionality leading them to a possible neuronal dysfunction.

Topics: Animals; Astrocytes; Disease Models, Animal; Glial Fibrillary Acidic Protein; Glutamate-Ammonia Ligase; Glycogen; Humans; Lafora Disease; Mice; Mice, Knockout

Canine Lafora disease (LD) is an autosomal recessive genetic disorder causing nonfatal structural epilepsy, mainly affecting miniature wirehaired dachshunds. Repeat expansion in the EPM2B gene causes a functional impairment of the ubiquitin ligase malin which regulates glycogen metabolism. Abnormally structured glycogen accumulates and develop polyglucosan bodies predominantly in the central nervous system. The authors performed a comprehensive clinical, genetic, and pathological study of 4 LD cases affecting miniature wirehaired dachshund dogs with EPM2B repeat expansions, with systemic distribution of polyglucosan bodies and accumulation of laforin and other functionally associated proteins in the polyglucosan bodies. Myoclonic seizures first appeared at 7-9 years of age, and the dogs died at 14-16 years of age. Immunohistochemistry for calbindin revealed that the polyglucosan bodies were located in the cell bodies and dendritic processes of Purkinje cells. Polyglucosan bodies were also positive for laforin, hsp70, α/β-synuclein, ubiquitin, LC3, and p62. Laforin-positive polyglucosan bodies were located in neurofilament-positive neurons but not in GFAP-positive astrocytes. In nonneural tissues, periodic acid-Schiff (PAS)-positive polyglucosan bodies were observed in the heart, skeletal muscle, liver, apocrine sweat gland, and smooth muscle layer of the urinary bladder. In the skeletal muscle, polyglucosan bodies were observed only in type 1 fibers and not in type 2 fibers. The results indicate that although the repeat expansion of the EPM2B gene is specific to dogs, the immunohistochemical properties of polyglucosan body in canine LD are comparable to human LD. However, important phenotypic variations exist between the 2 species including the affected skeletal muscle fiber type.

Topics: Animals; Astrocytes; Autophagy; Brain; Disease Models, Animal; Dog Diseases; Dogs; Female; Glucans; Glycogen; Humans; Immunohistochemistry; Inclusion Bodies; Lafora Disease; Male; Molecular Chaperones; Myoclonic Epilepsies, Progressive; Neurons; Neuropathology; Proteasome Endopeptidase Complex; Ubiquitin

Nonencapsulated Streptococcus pneumoniae bacteria are successful colonizers of the human nasopharynx and often possess genes aliB-like ORF 1 and 2 in place of capsule genes. AliB-like ORF 2 binds peptide FPPQSV, found in Prevotella species, resulting in enhanced colonization. How this response is mediated is so far unknown.. Here we show that the peptide increases expression of genes involved in release of host carbohydrates, carbohydrate uptake and carbohydrate metabolism. In particular, the peptide increased expression of 1,5-anhydro-D-fructose reductase, a metabolic enzyme of an alternative starch and glycogen degrading pathway found in many organisms, in both transcriptomic and proteomic data. The peptide enhanced pneumococcal growth giving a competitive advantage to a strain with aliB-like ORF 2, over its mutant lacking the gene. Possession of aliB-like ORF 2 did not affect release of inflammatory cytokine CXCL8 from epithelial cells in culture and the nonencapsulated wild type strain was not able to establish disease or inflammation in an infant rat model of meningitis.. We propose that AliB-like ORF 2 confers an advantage in colonization by enhancing carbohydrate metabolism resulting in a boost in growth. This may explain the widespread presence of aliB-like ORF 2 in the nonencapsulated pneumococcal population in the human nasopharynx.

Topics: Animals; Bacterial Capsules; Bacterial Proteins; Carbohydrate Metabolism; Carrier Proteins; Cell Line; Cytokines; Disease Models, Animal; Epithelial Cells; Gene Expression Regulation, Bacterial; Genes, Bacterial; Glycogen; Humans; Interleukin-8; Lipoproteins; Nasopharynx; Peptides; Pneumococcal Infections; Prevotella; Proteomics; Rats; Rats, Wistar; Starch; Streptococcus pneumoniae; Sugar Alcohol Dehydrogenases; Transcriptome

Kupffer cells (KCs) are key players in maintaining tissue homeostasis and are involved in various liver diseases. However, the roles of KCs in the pathogenesis of cholangiopathy are largely unknown. We aimed to investigate the precise roles of KCs in both the progression and regression phases of the 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC)-induced cholangiopathy model. In the early phase of DDC-induced cholangiopathy, the number of KCs significantly increased over time. Moreover, KCs were associated with abnormal phenotypic changes in other liver cells, such as hepatocytes, biliary epithelial cells, liver sinusoidal endothelial cells, and hepatic stellate cells. In contrast, KC depletion by clodronate administration suppressed the progression of the disease, and maintained the phenotypes of other cells. In the regression phase, the numbers of KCs significantly decreased, and the cells redifferentiated to their quiescent state. In contrast, KC depletion delayed the recovery of cells by maintaining other liver cells in an active state. These findings suggest that KCs play detrimental roles in the progression phase; however, they are beneficial in the regression phase by mediating interactions between other liver cells. Our data provide new insights into the roles of KCs in the pathogenesis of cholangiopathy.

Topics: Animals; Bile Duct Diseases; Disease Models, Animal; Disease Progression; Glycogen; Humans; Inflammation; Kupffer Cells; Liver; Mice; Phenotype; Pyridines; Splenomegaly

The primary aim of the present study was to evaluate the effects of liraglutide on glucolipotoxicity‑induced liver cell apoptosis and the underlying mechanisms in Zucker diabetic fatty (ZDF) rats. The results revealed that liraglutide significantly decreased the body weight, hyperglycemia and hyperlipidemia of ZDF rats relative to those of Zucker lean (ZL) rats (P<0.05). Furthermore, the reduced liver cell apoptosis was observed in the ZDF rats following 6 weeks of liraglutide therapy. These data validated the beneficial effects of liraglutide on diabetic and obese ZDF rats. In addition, novel data was obtained that demonstrated that liraglutide treatment increased the expression of the antioxidant transcription factor nuclear factor‑erythroid 2‑related factor 2 (NRF2), as well as the transcription of downstream target genes, including nicotinamide adenine dinucleotide phosphate quinone dehydrogenase 1 and heme oxygenase‑1 (P<0.05). Additionally, serum and hepatic GSH and SOD levels increased following liraglutide therapy (P<0.05). Hence, it was proposed that liraglutide may enhance the antioxidant activity of liver cells by activating the NRF2 signaling pathway, thereby reducing liver cell apoptosis induced by glucolipotoxicity in ZDF rats, which may shed light on the application of liraglutide in the treatment of diabetes‑ and obesity‑induced liver injury.

Topics: Animals; Apoptosis; Blood Glucose; Diabetes Mellitus, Experimental; Disease Models, Animal; Glycogen; Hepatocytes; Hypoglycemic Agents; Lipid Metabolism; Liraglutide; Male; NF-E2-Related Factor 2; Oxidative Stress; Rats; Rats, Zucker; Signal Transduction

Intravenous (IV) resuscitation of burn patients has greatly improved outcomes and become a cornerstone of modern burn care. However, the heavy fluids and vascular access required may not be feasible in austere environments, mass casualty, or delayed transport scenarios. Enteral resuscitation has been proposed for these situations; we sought to examine the effectiveness of this strategy on improving burn-induced kidney injury. Anesthetized Yorkshire swine sustaining 40% TBSA full-thickness contact burns were randomized to three groups (n = 6/group): fluid deprivation, ad libitum water access, or 70 mL/kg/d Oral Rehydration Salt solution (ORS). Urine and blood were collected at baseline (BL), 6, 12, 24, 32, and 48h post-burn, at which point tissue was harvested and CT angiography performed. Although fluid consumption by ad libitum and ORS groups were matched (132±54mL/kg versus 120±24mL/kg, respectively), ORS intake increased urine output compared with water and no water (47.3±9.0 mL/kg versus 16.1±2.5 mL/kg, and 24.5±1.7 mL/kg respectively). Plasma creatinine peaked 6h following burn (1.67±0.07mg/dL) in all animals, but at 48h was comparable to BL in animals receiving water (1.23±0.06mg/dL) and ORS (1.30±0.09mg/dL), but not fluid deprived animals (1.56±0.05mg/dL) (P<0.05). Circulating levels of blood urea nitrogen steadily increased, but also decreased by 48h in animals receiving enteral fluids (P<0.05). Water deprivation reduced renal artery diameter (-1.4±0.17mm), whereas resuscitation with water (-0.44±0.14 mm) or ORS maintained it (-0.63±0.20 mm;P< 0.02). Circulating cytokines IL-1β, IL-6, IFNγ, and GM-CSF were moderately elevated in the fluid-deprived group. Taken together, the data suggest that enteral resuscitation with ORS rescues kidney function following burn injury. Incorporating enteral fluids may improve outcomes in resource-poor environments and possibly reduce IV fluid requirements to prevent co-morbidities associated with over-resuscitation. Studies into different volumes/types of enteral fluids are warranted. While ORS has saved many lives in cholera-associated dehydration, it should be investigated further for use in burn patients.

Topics: Acute Kidney Injury; Animals; Burns; Disease Models, Animal; Enteral Nutrition; Female; Fluid Therapy; Glycogen; Kidney; Rehydration Solutions; Renal Artery; Swine; Vasoconstriction

Dyslipidaemia and hyperglycaemia are associated with ovarian failure and both have been related to hypothyroidism. Hypothyroidism promotes anovulation and ovarian cysts in women and reduces the size of follicles and the expression of aromatase in the ovary of rabbits. Considering that ovarian steroidogenesis and ovulation depend on lipid metabolism and signalling, the aim of the present study was to analyse the effect of hypothyroidism on the lipid content and expression of peroxisome proliferator-activated receptor (PPAR) δ in the ovary. Ovaries from female rabbits belonging to the control (n=7) and hypothyroid (n=7) groups were processed to measure total cholesterol (TC), triacylglycerol (TAG) and glycogen content, as well as to determine the presence of granules containing oxidized lipids (oxysterols and lipofuscin) and the relative expression of perilipin A (PLIN-A) and PPARδ. Hypothyroidism increased TC and glycogen content, but reduced TAG content in the ovary. This was accompanied by a reduction in the expression of PLIN-A in total and cytosolic extracts, changes in the presence of granules containing oxidative lipids and low PPARδ expression. The results of the present study suggest that hypothyroidism modifies the content and signalling of lipids in the ovary, possibly affecting follicle maturation. These results could improve our understanding of the association between hypothyroidism and infertility in females.

Topics: Animals; Cholesterol; Disease Models, Animal; Female; Glycogen; Hypothyroidism; Immunoblotting; Lipid Metabolism; Ovary; Perilipin-1; PPAR delta; Rabbits; Triglycerides

PIMT/NCOA6IP, a transcriptional coactivator PRIP/NCOA6 binding protein, enhances nuclear receptor transcriptional activity. Germline disruption of PIMT results in early embryonic lethality due to impairment of development around blastocyst and uterine implantation stages. We now generated mice with Cre-mediated cardiac-specific deletion of PIMT (csPIMT

Topics: Animals; Cardiomyopathies; Cardiomyopathy, Dilated; Disease Models, Animal; Energy Metabolism; Fibrosis; Gene Deletion; Gene Expression; Glucose; Glycogen; Mice; Mice, Knockout; Mitochondria; Myocardial Contraction; Myocardium; Myocytes, Cardiac; Nuclear Receptor Coactivators; Protein D-Aspartate-L-Isoaspartate Methyltransferase

Glycogen storage diseases (GSDs) of the liver are devastating disorders presenting with fasting hypoglycemia as well as hepatic glycogen and lipid accumulation, which could lead to long-term liver damage. Diet control is frequently utilized to manage the potentially dangerous hypoglycemia, but there is currently no effective pharmacological treatment for preventing hepatomegaly and concurrent liver metabolic abnormalities, which could lead to fibrosis, cirrhosis, and hepatocellular adenoma or carcinoma. In this study, we demonstrate that inhibition of glycogen synthesis using an RNAi approach to silence hepatic Gys2 expression effectively prevents glycogen synthesis, glycogen accumulation, hepatomegaly, fibrosis, and nodule development in a mouse model of GSD III. Mechanistically, reduction of accumulated abnormally structured glycogen prevents proliferation of hepatocytes and activation of myofibroblasts as well as infiltration of mononuclear cells. Additionally, we show that silencing Gys2 expression reduces hepatic steatosis in a mouse model of GSD type Ia, where we hypothesize that the reduction of glycogen also reduces the production of excess glucose-6-phosphate and its subsequent diversion to lipid synthesis. Our results support therapeutic silencing of GYS2 expression to prevent glycogen and lipid accumulation, which mediate initial signals that subsequently trigger cascades of long-term liver injury in GSDs.

Topics: Animals; Disease Models, Animal; Female; Fibroblasts; Glucose-6-Phosphate; Glycogen; Glycogen Storage Disease Type III; Glycogen Synthase; Hepatocytes; Hepatomegaly; Liver; Liver Cirrhosis; Male; Mice; Mice, Inbred C57BL; RNA Interference

The complexity of the pathogenic cascade in lysosomal storage disorders suggests that combination therapy will be needed to target various aspects of pathogenesis. The standard of care for Pompe disease (glycogen storage disease type II), a deficiency of lysosomal acid alpha glucosidase, is enzyme replacement therapy (ERT). Many patients have poor outcomes due to limited efficacy of the drug in clearing muscle glycogen stores. The resistance to therapy is linked to massive autophagic buildup in the diseased muscle. We have explored two strategies to address the problem. Genetic suppression of autophagy in muscle of knockout mice resulted in the removal of autophagic buildup, increase in muscle force, decrease in glycogen level, and near-complete clearance of lysosomal glycogen following ERT. However, this approach leads to accumulation of ubiquitinated proteins, oxidative stress, and exacerbation of muscle atrophy. Another approach involves AAV-mediated TSC knockdown in knockout muscle leading to upregulation of mTOR, inhibition of autophagy, reversal of atrophy, and efficient cellular clearance on ERT. Importantly, this approach reveals the possibility of reversing already established autophagic buildup, rather than preventing its development.

Topics: alpha-Glucosidases; Animals; Autophagy; Disease Models, Animal; Enzyme Replacement Therapy; Female; Glycogen; Glycogen Storage Disease Type II; Lysosomes; Male; Mice; Mice, Knockout; Muscle, Skeletal; TOR Serine-Threonine Kinases; Up-Regulation

BACKGROUND Whey acidic protein/four-disulfide core domain 21 (Wfdc21), also known as Lnc-DC, it has been reported to be correlated with immune response. However, the role of Wfdc21 in the pathogenesis of sepsis is still unknown. In the present study, we aimed to investigate the role of Wfdc21 in the pathogenesis of sepsis. MATERIAL AND METHODS The cecal ligation and puncture (CLP)-induced sepsis model was established in Balb/c mice. Animals were euthanized 4, 8, 16, or 24 h after CLP. The glycogen distribution in the kidney and liver was checked by Periodic acid-Schiff (PAS) staining. Changes in the serum interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) concentrations were monitored with ELISA, and Wdfc21 expression was determined by qPCR. Mouse macrophage-like RAW264.7 cells were treated with different doses of lipopolysaccharide (LPS) from Escherichia coli to mimic sepsis in vitro. Western blot analysis was performed to confirm whether LPS-induced in vitro sepsis was correlated with the involvement of the Stat3/TLR4 signaling pathway. In addition, RAW 264.7 cells were infected with lentiviruses containing Wfdc21 shRNA to further confirm the role of Wfdc21 in the pathogenesis of sepsis. RESULTS We found that Wfdc21 level was elevated in the CLP-induced animal model and LPS-treated RAW264.7 cells. Furthermore, the downregulation of Wfdc21 modulated the concentration of pro-inflammatory factors in LPS-treated macrophages, such as IL-1β and TNF-α, in LPS-treated macrophages. This regulatory effect was mediated through the Stat3/TLR4 signaling pathway, since Wfdc21 can regulate p-Stat3 and TLR4 levels in LPS-treated macrophages. CONCLUSIONS Wfdc21 plays a critical role in the pathogenesis of sepsis and may provide a therapeutic target for sepsis treatment.

Topics: Animals; Disease Models, Animal; Down-Regulation; Female; Glycogen; Interleukin-1beta; Lipopolysaccharides; Macrophages; Male; Mice; Mice, Inbred BALB C; RAW 264.7 Cells; RNA, Long Noncoding; Sepsis; Signal Transduction; STAT3 Transcription Factor; Toll-Like Receptor 4; Tumor Necrosis Factor-alpha

Topics: Animals; beta-Glucans; Biomarkers; Blood Glucose; Dietary Supplements; Disease Models, Animal; Energy Metabolism; Exercise Tolerance; Fatigue; Gene Expression Regulation; Glycogen; Liver; Male; Mice, Inbred ICR; Muscle Fatigue; Muscle, Skeletal; Oxidative Stress; Swimming; Time Factors

Topics: AMP-Activated Protein Kinase Kinases; AMP-Activated Protein Kinases; Animals; Biomarkers; Blood Glucose; Disease Models, Animal; Enzyme Activation; Fructose; Glucosides; Glycogen; Insulin; Insulin Resistance; Lipids; Lipogenesis; Liver; Male; Monoterpenes; Non-alcoholic Fatty Liver Disease; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins c-akt; Rats, Sprague-Dawley; Signal Transduction

Beckwith-Wiedemann syndrome (BWS) is a complex imprinting disorder involving fetal overgrowth and placentomegaly, and is associated with a variety of genetic and epigenetic mutations affecting the expression of imprinted genes on human chromosome 11p15.5. Most BWS cases are linked to loss of methylation at the imprint control region 2 (ICR2) within this domain, which in mice regulates the silencing of several maternally expressed imprinted genes. Modelling this disorder in mice is confounded by the unique embryonic requirement for

Topics: Animals; Basic Helix-Loop-Helix Transcription Factors; Beckwith-Wiedemann Syndrome; Biomarkers; Cell Lineage; Disease Models, Animal; Embryo Loss; Female; Fetal Growth Retardation; Fetus; Gene Expression Regulation, Developmental; Glycogen; Mice; Models, Genetic; Placenta; Pregnancy; Trophoblasts

Preeclampsia remains a clinical challenge due to its poorly understood pathogenesis. A prevailing notion is that increased placental production of soluble fms-like tyrosine kinase-1 (sFlt-1) causes the maternal syndrome by inhibiting proangiogenic placental growth factor (PlGF) and VEGF. However, the significance of PlGF suppression in preeclampsia is uncertain. To test whether preeclampsia results from the imbalance of angiogenic factors reflected by an abnormal sFlt-1/PlGF ratio, we studied PlGF KO (Pgf-/-) mice and noted that the mice did not develop signs or sequelae of preeclampsia despite a marked elevation in circulating sFLT-1. Notably, PlGF KO mice had morphologically distinct placentas, showing an accumulation of junctional zone glycogen. We next considered the role of placental PlGF in an established model of preeclampsia (pregnant catechol-O-methyltransferase-deficient [COMT-deficient] mice) by generating mice with deletions in both the Pgf and Comt genes. Deletion of placental PlGF in the context of COMT loss resulted in a reduction in maternal blood pressure and increased placental glycogen, indicating that loss of PlGF might be protective against the development of preeclampsia. These results identify a role for PlGF in placental development and support a complex model for the pathogenesis of preeclampsia beyond an angiogenic factor imbalance.

Topics: Animals; Blood Pressure; Disease Models, Animal; Female; Glycogen; Mice; Mice, Knockout; Models, Biological; Placenta; Placenta Growth Factor; Pre-Eclampsia; Pregnancy; Vascular Endothelial Growth Factor Receptor-1

Adult polyglucosan body disease (APBD) is a late-onset disease caused by intracellular accumulation of polyglucosan bodies, formed due to glycogen-branching enzyme (GBE) deficiency. To find a treatment for APBD, we screened 1,700 FDA-approved compounds in fibroblasts derived from APBD-modeling GBE1-knockin mice. Capitalizing on fluorescent periodic acid-Schiff reagent, which interacts with polyglucosans in the cell, this screen discovered that the flavoring agent guaiacol can lower polyglucosans, a result also confirmed in APBD patient fibroblasts. Biochemical assays showed that guaiacol lowers basal and glucose 6-phosphate-stimulated glycogen synthase (GYS) activity. Guaiacol also increased inactivating GYS1 phosphorylation and phosphorylation of the master activator of catabolism, AMP-dependent protein kinase. Guaiacol treatment in the APBD mouse model rescued grip strength and shorter lifespan. These treatments had no adverse effects except making the mice slightly hyperglycemic, possibly due to the reduced liver glycogen levels. In addition, treatment corrected penile prolapse in aged GBE1-knockin mice. Guaiacol's curative effects can be explained by its reduction of polyglucosans in peripheral nerve, liver, and heart, despite a short half-life of up to 60 minutes in most tissues. Our results form the basis to use guaiacol as a treatment and prepare for the clinical trials in APBD.

Topics: Animals; Disease Models, Animal; Dual-Specificity Phosphatases; Fibroblasts; Glucans; Glucose; Glycogen; Glycogen Storage Disease; Glycogen Synthase; Guaiacol; Heart; Kinetics; Liver; Mice; Mice, Inbred C57BL; Mice, Knockout; Nervous System Diseases; Peripheral Nerves; Phosphorylation; Protein Tyrosine Phosphatases, Non-Receptor; Ubiquitin-Protein Ligases

Malaria reduces host fitness and survival by pathogen-mediated damage and inflammation. Disease tolerance mechanisms counter these negative effects without decreasing pathogen load. Here, we demonstrate that in four different mouse models of malaria, adrenal hormones confer disease tolerance and protect against early death, independently of parasitemia. Surprisingly, adrenalectomy differentially affects malaria-induced inflammation by increasing circulating cytokines and inflammation in the brain but not in the liver or lung. Furthermore, without affecting the transcription of hepatic gluconeogenic enzymes, adrenalectomy causes exhaustion of hepatic glycogen and insulin-independent lethal hypoglycemia upon infection. This hypoglycemia is not prevented by glucose administration or TNF-α neutralization. In contrast, treatment with a synthetic glucocorticoid (dexamethasone) prevents the hypoglycemia, lowers cerebral cytokine expression and increases survival rates. Overall, we conclude that in malaria, adrenal hormones do not protect against lung and liver inflammation. Instead, they prevent excessive systemic and brain inflammation and severe hypoglycemia, thereby contributing to tolerance.

Topics: Adrenal Glands; Adrenalectomy; Animals; Blood Glucose; Brain; Corticosterone; Cytokines; Dexamethasone; Disease Models, Animal; Epinephrine; Glucocorticoids; Glycogen; Hormones; Hydrocortisone; Hypoglycemia; Inflammation; Liver; Lung; Malaria; Mice; Mineralocorticoids; Norepinephrine; Plasmodium berghei; Plasmodium chabaudi; Survival Rate

Pompe disease, which is due to acid alpha-glucosidase deficiency, is characterized by skeletal muscle dysfunction attributed to the accumulation of glycogen-filled lysosomes and autophagic buildup. Despite the extensive tissue damages, a failure of satellite cell (SC) activation and lack of muscle regeneration have been reported in patients. However, the origin of this defective program is unknown. Additionally, whether these deficits occur gradually over the disease course is unclear. Using a longitudinal pathophysiological study of two muscles in a Pompe mouse model, here, we report that the enzymatic defect results in a premature saturating glycogen overload and a high number of enlarged lysosomes. The muscles gradually display profound remodeling as the number of autophagic vesicles, centronucleated fibers, and split fibers increases and larger fibers are lost. Only a few regenerated fibers were observed regardless of age, although the SC pool was preserved. Except for the early age, during which higher numbers of activated SCs and myoblasts were observed, no myogenic commitment was observed in response to the damage. Following in vivo injury, we established that muscle retains regenerative potential, demonstrating that the failure of SC participation in repair is related to an activation signal defect. Altogether, our findings provide new insight into the pathophysiology of Pompe disease and highlight that the activation signal defect of SCs compromises muscle repair, which could be related to the abnormal energetic supply following autophagic flux impairment.

Topics: Age Factors; Animals; Autophagy; Cardiotoxins; Collagen; Disease Models, Animal; Dystrophin; Gene Expression Regulation; Glucan 1,4-alpha-Glucosidase; Glycogen; Glycogen Storage Disease Type II; Humans; Ki-67 Antigen; Laminin; Longitudinal Studies; Lysosomes; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Microtubule-Associated Proteins; Muscle, Skeletal; Regeneration; Satellite Cells, Skeletal Muscle

Pompe disease is a metabolic myopathy that is caused by glycogen accumulation as a result of deficiency of the lysosomal enzyme acid alpha glucosidase (GAA). Previously, we showed that adult muscle stem cells termed satellite cells are present at normal levels in muscle from patients with Pompe disease, but that these are insufficiently activated to repair the severe muscle pathology. Here we characterized the muscle regenerative response during disease progression in a mouse model of Pompe disease and investigated the intrinsic capacity of Gaa

Topics: Age Factors; alpha-Glucosidases; Animals; Barium Compounds; Cardiotoxins; Chlorides; Disease Models, Animal; Female; Glycogen; Glycogen Storage Disease Type II; Ki-67 Antigen; Laminin; Lysosomal-Associated Membrane Protein 1; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Muscle, Skeletal; PAX7 Transcription Factor; Regeneration; Satellite Cells, Skeletal Muscle

Topics: Adenosine Triphosphate; AMP-Activated Protein Kinases; Animals; Antrodia; Disease Models, Animal; Fatigue; Female; Glycogen; Liver; Liver Function Tests; Male; Mice; Muscle, Skeletal; Mycelium; Oxidation-Reduction; Oxidative Stress; Physical Conditioning, Animal; Proto-Oncogene Proteins c-akt; Signal Transduction; TOR Serine-Threonine Kinases

Lafora disease (LD) is a fatal progressive epilepsy essentially caused by loss-of-function mutations in the glycogen phosphatase laforin or the ubiquitin E3 ligase malin. Glycogen in LD is hyperphosphorylated and poorly hydrosoluble. It precipitates and accumulates into neurotoxic Lafora bodies (LBs). The leading LD hypothesis that hyperphosphorylation causes the insolubility was recently challenged by the observation that phosphatase-inactive laforin rescues the laforin-deficient LD mouse model, apparently through correction of a general autophagy impairment. We were for the first time able to quantify brain glycogen phosphate. We also measured glycogen content and chain lengths, LBs, and autophagy markers in several laforin- or malin-deficient mouse lines expressing phosphatase-inactive laforin. We find that: (i) in laforin-deficient mice, phosphatase-inactive laforin corrects glycogen chain lengths, and not hyperphosphorylation, which leads to correction of glycogen amounts and prevention of LBs; (ii) in malin-deficient mice, phosphatase-inactive laforin confers no correction; (iii) general impairment of autophagy is not necessary in LD We conclude that laforin's principle function is to control glycogen chain lengths, in a malin-dependent fashion, and that loss of this control underlies LD.

Topics: Animals; Brain; Disease Models, Animal; Dual-Specificity Phosphatases; Female; Glycogen; Lafora Disease; Male; Mice, Inbred C57BL; Molecular Weight; Phosphorylation; Protein Tyrosine Phosphatases, Non-Receptor; Ubiquitin-Protein Ligases

The present study was aimed to evaluate the modulatory effects of hydroalcoholic extract of Caralluma fimbriata (CFE) by assaying the activities of key enzymes of carbohydrate metabolism and changes in glycogen content (liver and muscle) in high-fat (HF) diet-induced diabetic rats. In vitro glucose uptake studies were carried out in both psoas muscle and adipose tissue. The inhibitory effect of the extract on α-amylase was determined in in vitro studies. Male Wistar rats of body weight around 180g were divided into five groups (n=8), two of these groups were fed with standard pellet diet and the other three groups were fed with HF- (60%) diet. CFE (200mg/kg body weight/day) was administered through oral route to each group of standard pellet diet rats and HF-fed rats and Metformin (Met) (20mg/kg body weight/day) was administered through oral route to HFD+Met group for 90 days. At the end of the experimental period, biochemical parameters related to glycogen content in liver and muscle, and intestinal disaccharidases like maltase, sucrase and lactase were assayed. Alterations in the activities of enzymes of glucose metabolism (hexokinase, phosphorfructoki nase, pyruvate kinase, glucose-6-phosphatase, fructose-1,6-bisphosphatase, and glucose-6-phosphate dehydrogenase), intestinal disaccharidases and glycogen content as observed in the high fat diet-fed rats were prevented with CFE/Met administration. From this study, we observed that CFE/Met could significantly restore the levels of glycogen in liver and muscle and key enzymes of carbohydrate metabolism to near normal in groups-HFD+CFE and HFD+Met. The skeletal muscle of HF-diet fed rats showed degenerative changes of muscle myofibers with fat deposition. These changes were attenuated in the HFD group treated with CFE/Met and retained their normal structure appearance. It can be concluded from these results that CFE might be of value in reducing the alterations related to carbohydrate metabolism under high calorie diet consumption.

Topics: Adipose Tissue; alpha-Amylases; Animals; Apocynaceae; Carbohydrate Metabolism; Diabetes Mellitus; Diet, High-Fat; Disaccharidases; Disease Models, Animal; Dose-Response Relationship, Drug; Glycogen; Glycolysis; Hypoglycemic Agents; Insulin; Intestines; Liver; Male; Metformin; Phytotherapy; Plant Extracts; Plants, Medicinal; Psoas Muscles; Rats, Wistar

Topics: Animals; Cardiomyopathies; Disease Models, Animal; Dual-Specificity Phosphatases; Echocardiography; Glycogen; Humans; Lafora Disease; Mice; Mice, Knockout; Mutation; Myocytes, Cardiac; Protein Tyrosine Phosphatases, Non-Receptor; Seizures; Stroke Volume; Ubiquitin-Protein Ligases; Ventricular Dysfunction, Left; Ventricular Remodeling

Pompe disease is a lysosomal storage disorder caused by acid-α-glucosidase (GAA) deficiency, leading to glycogen storage. The disease manifests as a fatal cardiomyopathy in infantile form. Enzyme replacement therapy (ERT) has recently prolonged the lifespan of these patients, revealing a new natural history. The neurologic phenotype and the persistence of selective muscular weakness in some patients could be attributed to the central nervous system (CNS) storage uncorrected by ERT. GAA-KO 6neo/6neo mice were treated with a single intrathecal administration of adeno-associated recombinant vector (AAV) mediated gene transfer of human GAA at 1 month and their neurologic, neuromuscular, and cardiac function was assessed for 1 year. We demonstrate a significant functional neurologic correction in treated animals from 4 months onward, a neuromuscular improvement from 9 months onward, and a correction of the hypertrophic cardiomyopathy at 12 months. The regions most affected by the disease i.e. the brainstem, spinal cord, and the left cardiac ventricular wall all show enzymatic, biochemical and histological correction. Muscle glycogen storage is not affected by the treatment, thus suggesting that the restoration of muscle functionality is directly related to the CNS correction. This unprecedented global and long-term CNS and cardiac cure offer new perspectives for the management of patients.

Topics: alpha-Glucosidases; Animals; Brain; Cardiomyopathy, Hypertrophic; Dependovirus; Disease Models, Animal; Genetic Therapy; Genetic Vectors; Glycogen; Glycogen Storage Disease Type II; HEK293 Cells; Humans; Injections, Spinal; Male; Muscle Strength; Random Allocation; Single-Blind Method; Spinal Cord

Topics: Adenosine Triphosphate; Animals; Coronary Circulation; Dietary Supplements; Disease Models, Animal; Energy Metabolism; Fatty Acids, Omega-3; Gene Expression Regulation; Glycogen; Inflammation Mediators; Lactic Acid; Male; Myocardial Infarction; Myocardium; Rats, Wistar; Signal Transduction; Soybean Oil; Systole; Time Factors; Ventricular Dysfunction, Left; Ventricular Function, Left

Lafora disease (LD) represents a fatal form of neurodegenerative disorder characterized by the presence of abnormally large number of polyglucosan bodies-called the Lafora bodies-in neurons and other tissues of the affected patients. The disease is caused by defects in the EPM2A gene coding for a protein phosphatase (laforin) or the NHLRC1 gene coding for an ubiquitin ligase (malin). Studies have shown that inhibition of glycogen synthesis in the brain could prevent the formation of Lafora bodies in the neurons and reduce seizure susceptibility in laforin-deficient mouse, an established animal model for LD. Since increased glucose uptake is thought to underlie increased glycogen in LD, and since the adipocyte hormone leptin is known to positively regulate the glucose uptake in neurons, we reasoned that blocking leptin signaling might reduce the neuronal glucose uptake and ameliorate the LD pathology. We demonstrate here that mice that were deficient for both laforin and leptin receptor showed a reduction in the glycogen level, Lafora bodies and gliosis in the brain, and displayed reduced susceptibility to induced seizures as compared to animals that were deficient only for laforin. Thus, blocking leptin signaling could be a one of the effective therapeutic strategies in LD.

Topics: Animals; Disease Models, Animal; Dual-Specificity Phosphatases; Genetic Predisposition to Disease; Glucans; Glycogen; Inclusion Bodies; Lafora Disease; Leptin; Mice; Neurons; Protein Tyrosine Phosphatases, Non-Receptor; Receptors, Leptin; Signal Transduction; Ubiquitin-Protein Ligases

Deficiency of glycogen branching enzyme (GBE) causes glycogen storage disease type IV (GSD IV), which is characterized by the accumulation of a less branched, poorly soluble form of glycogen called polyglucosan (PG) in multiple tissues. This study evaluates the efficacy of gene therapy with an adeno-associated viral (AAV) vector in a mouse model of adult form of GSD IV (Gbe1

Topics: 1,4-alpha-Glucan Branching Enzyme; Animals; Dependovirus; Disease Models, Animal; Genetic Therapy; Genetic Vectors; Glycogen; Glycogen Storage Disease Type IV; Humans; Liver; Male; Mice; Mice, Inbred C57BL; Muscle, Skeletal

Since it is known that placental overexpression of the human anti-angiogenic molecule sFlt-1, the main candidate in the progression of preeclampsia, lead to intrauterine growth restriction (IUGR) in mice by lentiviral transduction of mouse blastocysts, we hypothesize that sFlt-1 influence placental morphology and physiology resulting in fetal IUGR. We therefore examined the effect of sFlt-1 on placental morphology and physiology at embryonic day 18.5 with histologic and morphometric analyses, transcript analyses, immunoblotting, and methylation studies. Interestingly, placental overexpression of sFlt-1 leads to IUGR in the fetus and results in lower placental weights. Moreover, we observed altered trophoblast differentiation with reduced expression of IGF2, resulting in a smaller placenta, a smaller labyrinth, and the loss of glycogen cells in the junctional zone. Changes in IGF2 are accompanied by small changes in its DNA methylation, whereas overall DNA methylation is unaffected. In addition, the expression of placental nutrient transporters, such as the glucose diffusion channel Cx26, is decreased. In contrast, the expression of the fatty acid transporter CD36 and the cholesterol transporter ABCA1 is significantly increased. In conclusion, placental sFlt-1 overexpression resulted in a reduction in the differentiation of the spongiotrophoblast into glycogen cells. These findings of a reduced exchange area of the labyrinth and glycogen stores, as well as decreased expression of glucose transporter, could contribute to the intrauterine growth restriction phenotype. All of these factors change the intrauterine availability of nutrients. Thus, we speculate that the alterations triggered by increased anti-angiogenesis strongly affect fetal outcome and programming. J. Cell. Biochem. 118: 1316-1329, 2017. © 2016 Wiley Periodicals, Inc.

Topics: Animals; ATP Binding Cassette Transporter 1; CD36 Antigens; Cell Differentiation; Connexin 26; Connexins; Disease Models, Animal; DNA Methylation; Epigenesis, Genetic; Female; Fetal Growth Retardation; Glycogen; Humans; Insulin-Like Growth Factor II; Mice; Placenta; Pregnancy; Trophoblasts; Vascular Endothelial Growth Factor Receptor-1

Topics: Adrenal Medulla; Animals; Blood Glucose; Diabetes Mellitus, Type 2; Disease Models, Animal; Fasting; Glucose; Glucose Tolerance Test; Glycogen; Hypoxia; Insulin; Insulin Resistance; Liver; Male; Mice; Mice, Inbred C57BL; Oxygen; Oxyhemoglobins; Sleep Apnea, Obstructive

The involvement of brain glycogen in the progress of chronic stress-induced impairment of hippocampal astrocyte structural plasticity and depression-like behavior is yet to be clarified. The present study designed three experiments to determine the role of brain glycogen in the plasticity and behavioral consequences of chronic stress. Time course studies on brain glycogen, astrocytes, and behavioral responses to stress were conducted in Experiment 1. Chronic stress decreased the hippocampal glycogen levels, reduced astrocytic size and protrusion length in the hippocampus, and induced depression-like behavior. Glycogen synthase 1 mRNA in the hippocampus was silenced by lentiviral vector-based RNA interference (RNAi) in Experiment 2. This RNAi produced a lack of glycogen in the hippocampus, decreased the hippocampal astrocyte size, and induced depressive behavior in rats. The mechanisms of chronic stress-induced brain glycogen decrease were investigated in Experiment 3. Chronic stress promoted hippocampal glycogen breakdown and increased hippocampal glycogen synthesis. Results suggest that decreased glycogen content was associated with chronic stress-induced atrophy of hippocampal astrocyte size and depression-like behavior. Furthermore, the decrease of glycogen content in the hippocampus might be due to the compensation of glycogen synthesis for breakdown in an insufficient manner.

Topics: Animals; Astrocytes; Atrophy; Behavior, Animal; Depression; Disease Models, Animal; Glycogen; Hippocampus; Rats; Stress, Physiological

MicroRNAs (miRNAs) play important roles in epithelial-to-mesenchymal transition (EMT). Moreover, hyperglycaemia induces damage to renal tubular epithelial cells, which may lead to EMT in diabetic nephropathy. However, the effects of miRNAs on EMT in diabetic nephropathy are poorly understood. In the present study, we found that the level of microRNA-23b (miR-23b) was significantly decreased in high glucose (HG)-induced human kidney proximal tubular epithelial cells (HK2) and in kidney tissues of db/db mice. Overexpression of miR-23b attenuated HG-induced EMT, whereas knockdown of miR-23b induced normal glucose (NG)-mediated EMT in HK2 cells. Mechanistically, miR-23b suppressed EMT in diabetic nephropathy by targeting high mobility group A2 (HMGA2), thereby repressing PI3K-AKT signalling pathway activation. Additionally, HMGA2 knockdown or inhibition of the PI3K-AKT signalling pathway with LY294002 mimicked the effects of miR-23b overexpression on HG-mediated EMT, whereas HMGA2 overexpression or activation of the PI3K-AKT signalling pathway with BpV prevented the effects of miR-23b on HG-mediated EMT. We also confirmed that overexpression of miR-23b alleviated EMT, decreased the expression levels of EMT-related genes, ameliorated renal morphology, glycogen accumulation, fibrotic responses and improved renal functions in db/db mice. Taken together, we showed for the first time that miR-23b acts as a suppressor of EMT in diabetic nephropathy through repressing PI3K-AKT signalling pathway activation by targeting HMGA2, which maybe a potential therapeutic target for diabetes-induced renal dysfunction.

Topics: Animals; Cell Line; Chromones; Diabetic Nephropathies; Disease Models, Animal; Epithelial Cells; Epithelial-Mesenchymal Transition; Gene Expression Regulation; Glucose; Glycogen; HMGA2 Protein; Humans; Kidney Tubules, Proximal; Mice; Mice, Transgenic; MicroRNAs; Morpholines; Oligoribonucleotides; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Signal Transduction

Lipopolysaccharide (LPS) is known to impair insulin-stimulated muscle glucose uptake (MGU). We determined if increased glucose transport (GLUT4) or phosphorylation capacity (hexokinase II; HKII) could overcome the impairment in MGU. We used mice that overexpressed GLUT4 (GLUT4) or HKII (HK) in skeletal muscle. Studies were performed in conscious, chronically catheterized (carotid artery and jugular vein) mice. Mice received an intravenous bolus of either LPS (10 μg/g body weight) or vehicle (VEH). After 5 h, a hyperinsulinemic-euglycemic clamp was performed. As MGU is also dependent on cardiovascular function that is negatively affected by LPS, cardiac function was assessed using echocardiography. LPS decreased whole body glucose disposal and MGU in wild-type (WT) and HK mice. In contrast, the decrease was attenuated in GLUT4 mice. Although membrane-associated GLUT4 was increased in VEH-treated GLUT4 mice, LPS impaired membrane-associated GLUT4 in GLUT4 mice to the same level as LPS-treated WT mice. This suggested that overexpression of GLUT4 had further benefits beyond preserving transport activity. In fact, GLUT4 overexpression attenuated the LPS-induced decrease in cardiac function. The maintenance of MGU in GLUT4 mice following LPS was accompanied by sustained anaerobic glycolytic flux as suggested by increased muscle Pdk4 expression, and elevated lactate availability. Thus, enhanced glucose transport, but not phosphorylation capacity, ameliorates LPS-induced impairments in MGU. This benefit is mediated by long-term adaptations to the overexpression of GLUT4 that sustain muscle anaerobic glycolytic flux and cardiac function in response to LPS.

Topics: Animals; Blood Glucose; Disease Models, Animal; Glucose Transporter Type 4; Glycogen; Insulin; Lipopolysaccharides; Mice; Mice, Inbred C57BL; Muscle Proteins; Muscle, Skeletal; Phosphorylation

Due to the limitations of existing anti-diabetic drugs, the treatment of diabetes mellitus remains a significant challenge. The present study aimed to investigate the hypoglycemic, hypolipidemic and antioxidant effects of Paecilomyces tenuipes N45 extracts on alloxan-induced type I diabetes mellitus in mice. Diabetic Kunming mice were orally administered with water extract (WE) at doses of 2.50, 0.25 and 0.05 g/kg) or alcohol extract (AE) at doses of 2.00, 0.20 and 0.04 g/kg, for 3 weeks, following which the levels of factors associated with blood glucose, lipids and free radicals were determined. The anti-diabetic activities of AE and WE were further confirmed via an oral glucose tolerance test. Similar to the effects of metformin, Paecilomyces tenuipes N45 extracts led to a significant reduction in blood glucose levels, increase in serum insulin concentration and normalization in the densities of low-density lipoprotein cholesterol and high density lipoprotein cholesterol. The Paecilomyces tenuipes N45 extracts exerted antioxidative effects, indicated by regulation in the levels of superoxide dismutase, malondialdehyde and glutathione peroxidase. Taken together, the results of the present study demonstrated that Paecilomyces tenuipes N45 extract, a safe pharmaceutical agent, exerted anti-diabetic and anti-nephropathic activities and, thus, offers potential as a novel therapeutic agent in the treatment of diabetes.

Topics: Alloxan; Animals; Antioxidants; Blood Glucose; Body Weight; Diabetes Mellitus, Experimental; Disease Models, Animal; Glucose Tolerance Test; Glycogen; Hypoglycemic Agents; Hypolipidemic Agents; Insulin; Liver; Organ Size; Paecilomyces; Phytotherapy; Plant Extracts

External beam radiation therapy is a standard form of treatment for numerous cancers. Despite this, there are no approved methods to account for patient specific radiation sensitivity. In this report, Raman spectroscopy (RS) was used to identify radiation-induced biochemical changes in human non-small cell lung cancer xenografts. Chemometric analysis revealed unique radiation-related Raman signatures that were specific to nucleic acid, lipid, protein and carbohydrate spectral features. Among these changes was a dramatic shift in the accumulation of glycogen spectral bands for doses of 5 or 15 Gy when compared to unirradiated tumours. When spatial mapping was applied in this analysis there was considerable variability as we found substantial intra- and inter-tumour heterogeneity in the distribution of glycogen and other RS spectral features. Collectively, these data provide unique insight into the biochemical response of tumours, irradiated in vivo, and demonstrate the utility of RS for detecting distinct radiobiological responses in human tumour xenografts.

Topics: Animals; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Disease Models, Animal; Energy Metabolism; Female; Glycogen; Humans; Lung Neoplasms; Metabolomics; Organ Specificity; Principal Component Analysis; Radiation Tolerance; Spectrum Analysis, Raman; Xenograft Model Antitumor Assays

Glycogen storage disease type IIIa (GSD IIIa) is caused by a deficiency of glycogen debranching enzyme activity. Hepatomegaly, muscle degeneration, and hypoglycemia occur in human patients at an early age. Long-term complications include liver cirrhosis, hepatic adenomas, and generalized myopathy. A naturally occurring canine model of GSD IIIa that mimics the human disease has been described, with progressive liver disease and skeletal muscle damage likely due to excess glycogen deposition. In the current study, long-term follow-up of previously described GSD IIIa dogs until 32 mo of age (n = 4) and of family-owned GSD IIIa dogs until 11 to 12 y of age (n = 2) revealed that elevated concentrations of liver and muscle enzyme (AST, ALT, ALP, and creatine phosphokinase) decreased over time, consistent with hepatic cirrhosis and muscle fibrosis. Glycogen deposition in many skeletal muscles; the tongue, diaphragm, and heart; and the phrenic and sciatic nerves occurred also. Furthermore, the urinary biomarker Glc4, which has been described in many types of GSD, was first elevated and then decreased later in life. This urinary biomarker demonstrated a similar trend as AST and ALT in GSD IIIa dogs, indicating that Glc4 might be a less invasive biomarker of hepatocellular disease. Finally, the current study further demonstrates that the canine GSD IIIa model adheres to the clinical course in human patients with this disorder and is an appropriate model for developing novel therapies.

Topics: Age Factors; Animals; Biomarkers; Disease Models, Animal; Disease Progression; Dog Diseases; Dogs; Female; Glycogen; Glycogen Storage Disease Type III; Hepatomegaly; Liver; Liver Cirrhosis; Male; Muscle, Skeletal; Muscular Diseases; Species Specificity; Urolithiasis

Respiratory and/or lingual dysfunction are among the first motor symptoms in Pompe disease, a disorder resulting from absence or dysfunction of the lysosomal enzyme acid α-glucosidase (GAA). Here, we histologically evaluated the medulla, cervical and thoracic spinal cords in 6 weeks old asymptomatic Pompe (Gaa(-/-)) mice to determine if neuropathology in respiratory motor regions has an early onset. Periodic acid-Schiff (PAS) staining indicated glycogen accumulation was exclusively occurring in Gaa(-/-) hypoglossal, mid-cervical and upper thoracic motoneurons. Markers of DNA damage (Tunel) and ongoing apoptosis (Cleaved Caspase 3) did not co-localize with PAS staining, but were prominent in a medullary region which included the nucleus tractus solitarius, and also in the thoracic spinal dorsal horn. We conclude that respiratory-related motoneurons are particularly susceptible to GAA deficiency and that neuronal glycogen accumulation and neurodegeneration may occur independently in early stage disease. The data support early therapeutic intervention in Pompe disease.

Topics: Animals; Apoptosis; Calcium-Binding Proteins; Caspase 3; Cervical Vertebrae; Cohort Studies; Disease Models, Animal; DNA Damage; Glial Fibrillary Acidic Protein; Glycogen; Glycogen Storage Disease Type II; Medulla Oblongata; Mice, 129 Strain; Mice, Knockout; Microfilament Proteins; Motor Neurons; Neuroimmunomodulation; Spinal Cord; Thoracic Vertebrae

Enzyme replacement therapy (ERT) with recombinant human (rh) acid α-glucosidase (GAA) has prolonged the survival of patients. However, the paucity of cation-independent mannose-6-phosphate receptor (CI-MPR) in skeletal muscle, where it is needed to take up rhGAA, correlated with a poor response to ERT by muscle in Pompe disease. Clenbuterol, a selective β2 receptor agonist, enhanced the CI-MPR expression in striated muscle through Igf-1 mediated muscle hypertrophy, which correlated with increased CI-MPR (also the Igf-2 receptor) expression. In this study we have evaluated 4 new drugs in GAA knockout (KO) mice in combination with an adeno-associated virus (AAV) vector encoding human GAA, 3 alternative β2 agonists and dehydroepiandrosterone (DHEA). Mice were injected with AAV2/9-CBhGAA (1E+11 vector particles) at a dose that was not effective at clearing glycogen storage from the heart. Heart GAA activity was significantly increased by either salmeterol (p<0.01) or DHEA (p<0.05), in comparison with untreated mice. Furthermore, glycogen content was reduced in the heart by treatment with DHEA (p<0.001), salmeterol (p<0.05), formoterol (p<0.01), or clenbuterol (p<0.01) in combination with the AAV vector, in comparison with untreated GAA-KO mice. Wirehang testing revealed that salmeterol and the AAV vector significantly increased performance, in comparison with the AAV vector alone (p<0.001). Similarly, salmeterol with the vector increased performance significantly more than any of the other drugs. The most effective individual drugs had no significant effect in absence of vector, in comparison with untreated mice. Thus, salmeterol should be further developed as adjunctive therapy in combination with either ERT or gene therapy for Pompe disease.

Topics: alpha-Glucosidases; Animals; Clenbuterol; Dehydroepiandrosterone; Dependovirus; Disease Models, Animal; Enzyme Replacement Therapy; Genetic Therapy; Genetic Vectors; Glycogen; Glycogen Storage Disease Type II; Humans; Mice; Mice, Knockout; Myocardium; Salmeterol Xinafoate

While age-related insulin resistance and hyperinsulinemia are usually considered to be secondary to changes in muscle, the liver also plays a key role in whole-body insulin handling and its role in age-related changes in insulin homeostasis is largely unknown. Here, we show that patent pores called 'fenestrations' are essential for insulin transfer across the liver sinusoidal endothelium and that age-related loss of fenestrations causes an impaired insulin clearance and hyperinsulinemia, induces hepatic insulin resistance, impairs hepatic insulin signaling, and deranges glucose homeostasis. To further define the role of fenestrations in hepatic insulin signaling without any of the long-term adaptive responses that occur with aging, we induced acute defenestration using poloxamer 407 (P407), and this replicated many of the age-related changes in hepatic glucose and insulin handling. Loss of fenestrations in the liver sinusoidal endothelium is a hallmark of aging that has previously been shown to cause deficits in hepatic drug and lipoprotein metabolism and now insulin. Liver defenestration thus provides a new mechanism that potentially contributes to age-related insulin resistance.

Topics: Aging; Animals; Disease Models, Animal; Endothelial Cells; Glucose; Glycogen; Insulin; Insulin Resistance; Liver; Male; Mice, Inbred C57BL; Microcirculation; Poloxamer; Porosity; Rats, Inbred F344; Staining and Labeling

Sleep is viewed as a fundamental restorative function of the brain, but its specific role in neural energy budget remains poorly understood. Sleep deprivation dampens brain energy metabolism and impairs cognitive functions. Intriguingly, sleep fragmentation, despite normal total sleep duration, has a similar cognitive impact, and in this paper we ask the question of whether it may also impair brain energy metabolism. To this end, we used a recently developed mouse model of 2 weeks of sleep fragmentation and measured 2-deoxy-glucose uptake and glycogen, glucose and lactate concentration in different brain regions. In order to homogenize mice behaviour during metabolic measurements, we exposed them to a novel environment for 1 h. Using an intra-hippocampal electrode, we first showed that hippocampal electroencephalograph (EEG) response to exploration was unaltered by 1 or 14 days of sleep fragmentation. However, after 14 days, sleep fragmented mice exhibited a lower uptake of 2-deoxy-glucose in cortex and hippocampus and lower cortical lactate levels than control mice. Our results suggest that long-term sleep fragmentation impaired brain metabolism to a similar extent as total sleep deprivation without affecting the neuronal responsiveness of hippocampus to a novel environment.

Topics: Animals; Brain; Deoxyglucose; Disease Models, Animal; Electroencephalography; Energy Metabolism; Exploratory Behavior; Glycogen; Hippocampus; Lactic Acid; Male; Mice; Sleep; Sleep Deprivation; Time Factors

The regulation of microRNAs (miRNAs) at different stages of the progression of type 2 diabetes mellitus (T2DM) and their role in glucose homeostasis was investigated.. Microarrays were used to assess miRNA expression in skeletal muscle biopsies taken from healthy individuals and patients with pre-diabetes or T2DM, and insulin resistant offspring of rat dams fed a high fat diet during pregnancy.. Twenty-three miRNAs were differentially expressed in patients with T2DM, and 7 in the insulin resistant rat offspring compared to their controls. Among these, only one miRNA was similarly regulated: miR-194 expression was significantly reduced by 25 to 50% in both the rat model and in human with pre-diabetes and established diabetes. Knockdown of miR-194 in L6 skeletal muscle cells induced an increase in basal and insulin-stimulated glucose uptake and glycogen synthesis. This occurred in conjunction with an increased glycolysis, indicated by elevated lactate production. Moreover, oxidative capacity was also increased as we found an enhanced glucose oxidation in presence of the mitochondrial uncoupler FCCP. When miR-194 was down-regulated in vitro, western blot analysis showed an increased phosphorylation of AKT and GSK3β in response to insulin, and an increase in expression of proteins controlling mitochondrial oxidative phosphorylation.. Type 2 diabetes mellitus is associated with regulation of several miRNAs in skeletal muscle. Interestingly, miR-194 was a unique miRNA that appeared regulated across different stages of the disease progression, from the early stages of insulin resistance to the development of T2DM. We have shown miR-194 is involved in multiple aspects of skeletal muscle glucose metabolism from uptake, through to glycolysis, glycogenesis and glucose oxidation, potentially via mechanisms involving AKT, GSK3 and oxidative phosphorylation. MiR-194 could be down-regulated in patients with early features of diabetes as an adaptive response to facilitate tissue glucose uptake and metabolism in the face of insulin resistance.

Topics: Animals; Cell Line; Diabetes Mellitus, Type 2; Diet, High-Fat; Disease Models, Animal; Female; Gene Expression Regulation; Glucose; Glycogen; Glycogen Synthase Kinase 3; Humans; Insulin; Insulin Resistance; Male; Mice, Inbred C57BL; MicroRNAs; Mitochondria; Muscle, Skeletal; Myoblasts; Oxidative Phosphorylation; Prediabetic State; Proto-Oncogene Proteins c-akt; Rats; Rats, Sprague-Dawley; Signal Transduction

Ectopic lipid accumulation in the liver is an almost universal feature of human and rodent models of generalized lipodystrophy and is also a common feature of type 2 diabetes, obesity, and metabolic syndrome. Here we explore the progression of fatty liver disease using a mouse model of lipodystrophy created by a fat-specific knockout of the insulin receptor (F-IRKO) or both IR and insulin-like growth factor 1 receptor (F-IR/IGFRKO). These mice develop severe lipodystrophy, diabetes, hyperlipidemia, and fatty liver disease within the first weeks of life. By 12 weeks of age, liver demonstrated increased reactive oxygen species, lipid peroxidation, histological evidence of balloon degeneration, and elevated serum alanine aminotransferase and aspartate aminotransferase levels. In these lipodystrophic mice, stored liver lipids can be used for energy production, as indicated by a marked decrease in liver weight with fasting and increased liver fibroblast growth factor 21 expression and intact ketogenesis. By 52 weeks of age, liver accounted for 25% of body weight and showed continued balloon degeneration in addition to inflammation, fibrosis, and highly dysplastic liver nodules. Progression of liver disease was associated with improvement in blood glucose levels, with evidence of altered expression of gluconeogenic and glycolytic enzymes. However, these mice were able to mobilize stored glycogen in response to glucagon. Feeding F-IRKO and F-IR/IGFRKO mice a high-fat diet for 12 weeks accelerated the liver injury and normalization of blood glucose levels. Thus, severe fatty liver disease develops early in lipodystrophic mice and progresses to advanced nonalcoholic steatohepatitis with highly dysplastic liver nodules. The liver injury is propagated by lipotoxicity and is associated with improved blood glucose levels.

Topics: Adipose Tissue; Alanine Transaminase; Animals; Blood Glucose; Diet, High-Fat; Disease Models, Animal; Fatty Liver; Fibroblast Growth Factors; Glucose Tolerance Test; Glycogen; Immunoblotting; Immunohistochemistry; Insulin-Like Growth Factor I; Lipodystrophy; Liver; Mice; Mice, Knockout; Non-alcoholic Fatty Liver Disease; Receptor, Insulin

Muscle wasting prevails in numerous diseases (e.g. diabetes, cardiovascular and kidney diseases, COPD,…) and increases healthcare costs. A major clinical issue is to devise new strategies preventing muscle wasting. We hypothesized that 8-week docosahexaenoic acid (DHA) supplementation prior to fasting may preserve muscle mass. Six-week-old C57BL/6 mice were fed a DHA-enriched or a control diet for 8 weeks and then fasted for 48 h.. Feeding mice a DHA-enriched diet prior to fasting elevated muscle glycogen contents, reduced muscle wasting, blocked the 55% decrease in Akt phosphorylation, and reduced by 30-40% the activation of AMPK, ubiquitination, or autophagy. The DHA-enriched diet fully abolished the fasting induced-messenger RNA (mRNA) over-expression of the endocannabinoid receptor-1. Finally, DHA prevented or modulated the fasting-dependent increase in muscle mRNA levels for Rab18, PLD1, and perilipins, which determine the formation and fate of lipid droplets, in parallel with muscle sparing.. These data suggest that 8-week DHA supplementation increased energy stores that can be efficiently mobilized, and thus preserved muscle mass in response to fasting through the regulation of Akt- and AMPK-dependent signalling pathways for reducing proteolysis activation. Whether a nutritional strategy aiming at increasing energy status may shorten recovery periods in clinical settings remains to be tested.

Topics: Adenosine Triphosphate; Animals; Dietary Supplements; Disease Models, Animal; Docosahexaenoic Acids; Endocannabinoids; Fasting; Fatty Acids; Gene Expression Regulation; Glycogen; Lipid Droplets; Lipid Metabolism; Mice; Mitogen-Activated Protein Kinases; Muscular Atrophy; Organ Size; Proteasome Endopeptidase Complex; Proteolysis; Proto-Oncogene Proteins c-akt; Signal Transduction; Ubiquitin; Ubiquitination

Muscle unit (MU) fibers innervated by one motoneuron and corresponding muscle fiber types are normally distributed in a mosaic. We asked whether, 4-8months after common peroneal nerve transection and random surgical alignment of nerve stumps in rat tibialis anterior muscles 1) reinnervated MU muscle and muscle fiber type clumping is invariant and 2) slow and fast motoneurons regenerate their nerve fibers within original endoneurial pathways. MU contractile forces were recorded in vivo, the MUs classified into types according to their contractile speed and fatigability, and one MU subjected to alternate exhaustive stimulation-recovery cycles to deplete glycogen for histochemical MU fiber recognition and enumeration, and muscle fiber typing. MU muscle fibers occupied defined territories whose size increased with MU force and muscle fiber numbers in normal and reinnervated muscles. The reinnervated MU muscle fiber territories were significantly smaller, the fibers clumped within 1-3 groups in 90% of the MUs, and each fiber lying adjacent to another significantly more frequently. Most reinnervated slow muscle fibers were normally located in the deep muscle compartment but substantial numbers were located abnormally in the superficial compartment. Our findings that well reinnervated muscle fibers clump in small muscles contrast with our earlier findings of clumping in large muscles only when reinnervated MU numbers were significantly reduced. We conclude that fiber type clumping is predictive of muscle reinnervation in small but not large muscles. In the latter muscles, clumping is more indicative of sprouting after partial nerve injuries than of muscle reinnervation after complete nerve injuries.

Topics: Animals; Disease Models, Animal; Electric Stimulation; Electromyography; Evoked Potentials, Motor; Glycogen; Motor Neurons; Muscle Contraction; Muscle Fibers, Skeletal; Muscle, Skeletal; Nerve Regeneration; Peripheral Nervous System Diseases; Rats; Rats, Sprague-Dawley

Insulin secretion from pancreatic β-cells is impaired in all forms of diabetes. The resultant hyperglycaemia has deleterious effects on many tissues, including β-cells. Here we show that chronic hyperglycaemia impairs glucose metabolism and alters expression of metabolic genes in pancreatic islets. In a mouse model of human neonatal diabetes, hyperglycaemia results in marked glycogen accumulation, and increased apoptosis in β-cells. Sulphonylurea therapy rapidly normalizes blood glucose levels, dissipates glycogen stores, increases autophagy and restores β-cell metabolism. Insulin therapy has the same effect but with slower kinetics. Similar changes are observed in mice expressing an activating glucokinase mutation, in in vitro models of hyperglycaemia, and in islets from type-2 diabetic patients. Altered β-cell metabolism may underlie both the progressive impairment of insulin secretion and reduced β-cell mass in diabetes.

Topics: Animals; Apoptosis; Autophagy; Blood Glucose; Cell Line; Diabetes Mellitus, Type 2; Disease Models, Animal; Glucokinase; Glycogen; Humans; Hyperglycemia; Hypoglycemic Agents; In Vitro Techniques; Infant, Newborn; Infant, Newborn, Diseases; Insulin; Insulin-Secreting Cells; Mice; Mutation; Rats; Sulfonylurea Compounds

Non-alcoholic fatty liver disease (NAFLD) is a major health problem and occurs frequently in the context of metabolic syndrome and type 2 diabetes mellitus. Hepatocyte-specific Pten-deficiency in mice was shown previously to result in hepatic steatosis due to hyperactivated AKT2. However, the role of peripheral insulin-sensitive tissues on PTEN- and AKT2-dependent accumulation of hepatic lipids has not been addressed.. Effects of systemically perturbed PTEN/AKT2 signalling on hepatic lipid content were studied in Pten-haplodeficient (Pten(+/-) /Akt2(+/+) ) mice and Pten-haplodeficient mice lacking Akt2 (Pten(+/-) /Akt2(-/-) ). The liver and skeletal muscle were characterized by histology and/or analysis of insulin signalling. To assess the effects of AKT2 activity in skeletal muscle on hepatic lipid content, AKT2 mutants were expressed in skeletal muscle of Pten(+/+) /Akt2(+/+) and Pten(+/-) /Akt2(+/+) mice using adeno-associated virus 8.. Pten(+/-) /Akt2(+/+) mice were found to have a more than 2-fold reduction in hepatic lipid content, at a level similar to that observed in Pten(+/-) /Akt2(-/-) mice. Insulin signalling in the livers of Pten(+/-) /Akt2(+/+) mice was enhanced, indicating that extrahepatic factors prevent lipid accumulation. The skeletal muscle of Pten(+/-) /Akt2(+/+) mice also showed enhanced insulin signalling. Skeletal muscle-specific expression of constitutively active AKT2 reduced hepatic lipid content in Pten(+/+) /Akt2(+/+) mice, and dominant negative AKT2 led to an increase in accumulation of hepatic lipids in both Pten(+/+) /Akt2(+/+) and Pten(+/-) /Akt2(+/+) mice.. Our results demonstrate that AKT2 activity in skeletal muscle critically affects lipid accumulation in the livers of Pten(+/+) /Akt2(+/+) and Pten(+/-) /Akt2(+/+) mice, and emphasize the role of skeletal muscle in the pathology of NAFLD.

Topics: Animals; Blood Glucose; Disease Models, Animal; Enzyme Activation; Genotype; Glycogen; Haploinsufficiency; Insulin; Lipid Metabolism; Liver; Male; Mice, Inbred C57BL; Mice, Knockout; Muscle, Skeletal; Mutation; Non-alcoholic Fatty Liver Disease; Phenotype; Proto-Oncogene Proteins c-akt; PTEN Phosphohydrolase; Signal Transduction; Time Factors

Glycogen is a branched polymer of glucose that acts as an energy reserve in many cell types. Glycogen contains trace amounts of covalent phosphate, in the range of 1 phosphate per 500-2000 glucose residues depending on the source. The function, if any, is unknown, but in at least one genetic disease, the progressive myoclonic epilepsy Lafora disease, excessive phosphorylation of glycogen has been implicated in the pathology by disturbing glycogen structure. Some 90% of Lafora cases are attributed to mutations of the EPM2A or EPM2B genes, and mice with either gene disrupted accumulate hyperphosphorylated glycogen. It is, therefore, of importance to understand the chemistry of glycogen phosphorylation. Rabbit skeletal muscle glycogen contained covalent phosphate as monoesters of C2, C3, and C6 carbons of glucose residues based on analyses of phospho-oligosaccharides by NMR. Furthermore, using a sensitive assay for glucose 6-P in hydrolysates of glycogen coupled with measurement of total phosphate, we determined the proportion of C6 phosphorylation in rabbit muscle glycogen to be ∼20%. C6 phosphorylation also accounted for ∼20% of the covalent phosphate in wild type mouse muscle glycogen. Glycogen phosphorylation in Epm2a(-/-) and Epm2b(-/-) mice was increased 8- and 4-fold compared with wild type mice, but the proportion of C6 phosphorylation remained unchanged at ∼20%. Therefore, our results suggest that C2, C3, and/or C6 phosphate could all contribute to abnormal glycogen structure or to Lafora disease.

Topics: Animals; Disease Models, Animal; Dual-Specificity Phosphatases; Glucose-6-Phosphate; Glycogen; Humans; Lafora Disease; Mice; Mice, Transgenic; Mutation; Phosphorylation; Protein Tyrosine Phosphatases, Non-Receptor; Rabbits; Ubiquitin-Protein Ligases

Long-term exposure to stress or high glucocorticoid levels leads to depression-like behavior in rodents; however, the cause remains unknown. Increasing evidence shows that astrocytes, the most abundant cells in the central nervous system (CNS), are important to the nervous system. Astrocytes nourish and protect the neurons, and serve as glycogen repositories for the brain. The metabolic process of glycogen, which is closely linked to neuronal activity, can supply sufficient energy substrates for neurons. The research team probed into the effects of chronic corticosterone (CORT) exposure on the glycogen level of astrocytes in the hippocampal tissues of male C57BL/6N mice in this study. The results showed that chronic CORT injection reduced hippocampal neurofilament light protein (NF-L) and synaptophysin (SYP) levels, induced depression-like behavior in male mice, reduced hippocampal glycogen level and glycogen synthase activity, and increased glycogen phosphorylase activity. The results suggested that the reduction of the hippocampal glycogen level may be the mechanism by which chronic CORT treatment damages hippocampal neurons and induces depression-like behavior in male mice.

Topics: Animals; Astrocytes; Behavior, Animal; Brain; Corticosterone; Depression; Disease Models, Animal; Glycogen; Glycogen Phosphorylase; Glycogen Synthase; Hippocampus; Male; Mice; Mice, Inbred C57BL; Neurofilament Proteins; Neurons; Synaptophysin

This study biochemically determined glycogen content in the axotomized facial nucleus of adult rats up to 35 days postinsult. The amounts of glycogen in the transected facial nucleus were significantly increased at 5 days postinsult, peaked at 7 days postinsult, and declined to the control levels at 21-35 days postinsult. Immunohistochemical analysis with antiglycogen antibody revealed that the quantity of glycogen granules in the axotomized facial nucleus was greater than that in the control nucleus at 7 days postinjury. Dual staining methods with antiglycogen antibody and a motoneuron marker clarified that the glycogen was localized mainly in motoneurons. Immunoblotting and quantification analysis revealed that the ratio of inactive glycogen synthase (GS) to total GS was significantly decreased in the injured nucleus at about 1-3 days postinsult and significantly increased from 7 to 14 days postinsult, suggesting that glycogen is actively synthesized in the early period postinjury but suppressed after 7 days postinsult. The enhanced glycogen at about 5-7 days postinsult is suggested to be responsible for the decrease in inactive GS levels, and the decrease of glycogen after 7 days postinsult is considered to be caused by increased inactive GS levels and possibly the increase in active glycogen phosphorylase.

Topics: Animals; Axotomy; Disease Models, Animal; Facial Nucleus; Glial Fibrillary Acidic Protein; Glucose; Glycogen; Glycogen Synthase; Male; Motor Neurons; Rats; Rats, Wistar; Time Factors

Mutations in the secreted glycoprotein ADAMTSL2 cause recessive geleophysic dysplasia (GD) in humans and Musladin-Lueke syndrome (MLS) in dogs. GD is a severe, often lethal, condition presenting with short stature, brachydactyly, stiff skin, joint contractures, tracheal-bronchial stenosis and cardiac valve anomalies, whereas MLS is non-lethal and characterized by short stature and severe skin fibrosis. Although most mutations in fibrillin-1 (FBN1) cause Marfan syndrome (MFS), a microfibril disorder leading to transforming growth factor-β (TGFβ) dysregulation, domain-specific FBN1 mutations result in dominant GD. ADAMTSL2 has been previously shown to bind FBN1 and latent TGFβ-binding protein-1 (LTBP1). Here, we investigated mice with targeted Adamtsl2 inactivation as a new model for GD (Adamtsl2(-/-) mice). An intragenic lacZ reporter in these mice showed that ADAMTSL2 was produced exclusively by bronchial smooth muscle cells during embryonic lung development. Adamtsl2(-/-) mice, which died at birth, had severe bronchial epithelial dysplasia with abnormal glycogen-rich inclusions in bronchial epithelium resembling the cellular anomalies described previously in GD. An increase in microfibrils in the bronchial wall was associated with increased FBN2 and microfibril-associated glycoprotein-1 (MAGP1) staining, whereas LTBP1 staining was increased in bronchial epithelium. ADAMTSL2 was shown to bind directly to FBN2 with an affinity comparable to FBN1. The observed extracellular matrix (ECM) alterations were associated with increased bronchial epithelial TGFβ signaling at 17.5 days of gestation; however, treatment with TGFβ-neutralizing antibody did not correct the epithelial dysplasia. These investigations reveal a new function of ADAMTSL2 in modulating microfibril formation, and a previously unsuspected association with FBN2. Our studies suggest that the bronchial epithelial dysplasia accompanying microfibril dysregulation in Adamtsl2(-/-) mice cannot be reversed by TGFβ neutralization, and thus might be mediated by other mechanisms.

Topics: ADAMTS Proteins; Animals; Animals, Newborn; Bone Diseases, Developmental; Bronchi; Cellular Microenvironment; Disease Models, Animal; Epithelium; Extracellular Matrix; Extracellular Matrix Proteins; Fibrillin-1; Fibrillin-2; Fibrillins; Gene Deletion; Glycogen; Limb Deformities, Congenital; Mice, Inbred C57BL; Microfibrils; Microfilament Proteins; Protein Binding; Signal Transduction; Transforming Growth Factor beta

This is the first study to analyse the effect of muscle glycogen phosphorylase depletion in metabolically different muscle types. In McArdle mice, muscle glycogen phosphorylase is absent in both oxidative and glycolytic muscles. In McArdle mice, the glycogen debranching enzyme (catabolic) is increased in oxidative muscles, whereas the glycogen branching enzyme (anabolic) is increased in glycolytic muscles. In McArdle mice, total glycogen synthase is decreased in both oxidative and glycolytic muscles, whereas the phosphorylated inactive form of the enzyme is increased in both oxidative and glycolytic enzymes. In McArdle mice, glycogen content is higher in glycolytic muscles than in oxidative muscles. Additionally, in all muscles analysed, the glycogen content is higher in males than in females. The maximal endurance capacity of the McArdle mice is significantly lower compared to heterozygous and wild-type mice.. McArdle disease, caused by inherited deficiency of the enzyme muscle glycogen phosphorylase (GP-MM), is arguably the paradigm of exercise intolerance. The recent knock-in (p.R50X/p.R50X) mouse disease model allows an investigation of the phenotypic consequences of muscle glycogen unavailability and the physiopathology of exercise intolerance. We analysed, in 2-month-old mice [wild-type (wt/wt), heterozygous (p.R50X/wt) and p.R50X/p.R50X)], maximal endurance exercise capacity and the molecular consequences of an absence of GP-MM in the main glycogen metabolism regulatory enzymes: glycogen synthase, glycogen branching enzyme and glycogen debranching enzyme, as well as glycogen content in slow-twitch (soleus), intermediate (gastrocnemius) and glycolytic/fast-twitch (extensor digitorum longus; EDL) muscles. Compared with wt/wt, exercise capacity (measured in a treadmill test) was impaired in p.R50X/p.R50X (∼48%) and p.R50X/wt mice (∼18%). p.R50X/p.R50X mice showed an absence of GP-MM in the three muscles. GP-MM was reduced in p.R50X/wt mice, especially in the soleus, suggesting that the function of 'slow-twitch' muscles is less dependent on glycogen catabolism. p.R50X/p.R50X mice showed increased glycogen debranching enzyme in the soleus, increased glycogen branching enzyme in the gastrocnemius and EDL, as well as reduced levels of mucle glycogen synthase protein in the three muscles (mean ∼70%), reflecting a protective mechanism for preventing deleterious glycogen accumulation. Additionally, glycogen content was highest in the EDL of p.R50X/p.R50X mice. Amongst other findings, the present study shows that the expression of the main muscle glycogen regulatory enzymes differs depending on the muscle phenotype (slow- vs. fast-twitch) and that even partial GP-MM deficiency affects maximal endurance capacity. Our knock-in model might help to provide insights into the importance of glycogen on muscle function.

Topics: Animals; Disease Models, Animal; Female; Glycogen; Glycogen Phosphorylase; Glycogen Storage Disease Type V; Male; Mice, Transgenic; Muscle, Skeletal; Phenotype; Physical Conditioning, Animal; Protein Isoforms; RNA, Messenger

Major aims were to determine whether exposure to the commonly used food additive carrageenan could induce fasting hyperglycemia and could increase the effects of a high fat diet on glucose intolerance and dyslipidemia.. C57BL/6J mice were exposed to either carrageenan, high fat diet, or the combination of high fat diet and carrageenan, or untreated, for one year. Effects on fasting blood glucose, glucose tolerance, lipid parameters, weight, glycogen stores, and inflammation were compared.. Exposure to carrageenan led to glucose intolerance by six days and produced elevated fasting blood glucose by 23 weeks. Effects of carrageenan on glucose tolerance were more severe than from high fat alone. Carrageenan in combination with high fat produced earlier onset of fasting hyperglycemia and higher glucose levels in glucose tolerance tests and exacerbated dyslipidemia. In contrast to high fat, carrageenan did not lead to weight gain. In hyperinsulinemic, euglycemic clamp studies, the carrageenan-exposed mice had higher early glucose levels and lower glucose infusion rate and longer interval to achieve the steady-state.. Carrageenan in the Western diet may contribute to the development of diabetes and the effects of high fat consumption. Carrageenan may be useful as a nonobese model of diabetes in the mouse.

Topics: Animals; Blood Glucose; Body Weight; Carrageenan; Diet; Diet, High-Fat; Disease Models, Animal; Dyslipidemias; Food Additives; Food Deprivation; Glucose; Glucose Tolerance Test; Glycated Hemoglobin; Glycogen; Hyperglycemia; Hyperlipidemias; Inflammation; Lipids; Male; Mice; Mice, Inbred C57BL; Risk Factors

The effect of a long-term high-fat, high-caloric diet on the dysfunction of pancreas has not been clarified. We investigated the pancreatic histopathology and β-cell apoptosis in Bama minipigs after 23 months on a high-fat high-sucrose diet (HFHSD).. Bama minipigs were randomly assigned to control (n = 6) and HFHSD groups (n = 6) for 23 months, and biochemical parameters were measured. Pancreata were subjected to histological analysis, followed by assessment with transmission electron microscopy. Lipid peroxidation was determined by the malondialdehyde concentration and antioxidant enzyme activity. Β-cell apoptosis was measured by an immunohistochemical method.. In the HFHSD group, the islets were enlarged, and the pancreatic tissue had observed significant fatty infiltration. Moreover, the feeding program damaged the normal pancreatic tissue structure. The level of lipid peroxidation was increased, and the activities of pancreatic antioxidant enzymes were significantly decreased. The expression levels of caspase-3, Bax, and insulin were significantly increased (P < 0.05), and the expression levels of proliferating cell nuclear antigen and Bcl-2 were decreased (P < 0.05).. The long-term HFHSD promotes pancreatic steatosis and oxidative stress, which increases β-cell apoptosis as indicated by the activation of caspase-3 through the mitochondrial pathway (Bcl-2/Bax).

Topics: Animals; Antioxidants; Apoptosis; bcl-2-Associated X Protein; Biomarkers; Blood Glucose; Caspase 3; Cell Proliferation; Diet, High-Fat; Dietary Sucrose; Disease Models, Animal; Glycogen; Hyperinsulinism; Insulin; Insulin-Secreting Cells; Islets of Langerhans; Lipid Peroxidation; Malondialdehyde; Obesity; Oxidative Stress; Pancreatic Diseases; Proto-Oncogene Proteins c-bcl-2; Swine; Swine, Miniature; Time Factors

We have recently reported on the pathology of the neuromuscular junction (NMJ) in Pompe disease, reflecting disruption of neuronal and muscle homeostasis as a result of glycogen accumulation. The aim of this study was to examine how the alteration of NMJ physiology contributes to Pompe disease pathology; we performed molecular, physiological, and histochemical analyses of NMJ-related measures of the tibialis anterior muscles of young-, mid-, and late-stage alpha-glucosidase (GAA)-deficient mice.. We performed intramuscular injection of an adeno-associated virus (AAV)9 vector expressing GAA (AAV9-hGAA) into the tibialis anterior muscle of Gaa(-/-) mice at early, mid, and severe pathological time points. We analyzed expression of NMJ-related genes, in situ muscle force production, and clearance of glycogen in conjunction with histological assessment of the NMJ.. Our data demonstrate that AAV9-hGAA is able to replace GAA to the affected tissue and modify AChR mRNA expression, muscle force production, motor endplate area, and innervation status. Importantly, the degree of restoration for these outcomes is limited by severity of disease. Early restoration of GAA activity was most effective, whereas late correction of GAA expression was not effective in modifying parameters reflecting NMJ structure and function nor in force restoration despite resolution of glycogen storage in muscle.. Our data provide new mechanistic insight into the pathology of Pompe disease and suggest that early systemic correction to both neural and muscle tissues may be essential for successful correction of neuromuscular function in Pompe disease. Ann Neurol 2015;78:222-234.

Topics: alpha-Glucosidases; Animals; Dependovirus; Disease Models, Animal; Genetic Therapy; Genetic Vectors; Glycogen; Glycogen Storage Disease Type II; Hindlimb; Injections, Intramuscular; Isometric Contraction; Mice; Mice, Knockout; Muscle Strength; Muscle, Skeletal; Neuromuscular Junction; Receptors, Cholinergic; RNA, Messenger; Time Factors

Our previous study showed that chromium malate improved the regulation of blood glucose in mice with alloxan-induced diabetes. The present study was designed to evaluate the effect of chromium malate on glycometabolism, glycometabolism-related enzymes and lipid metabolism in type 2 diabetic rats. Our results showed that fasting blood glucose, serum insulin level, insulin resistance index and C-peptide level in the high dose group had a significant downward trend when compared with the model group, chromium picolinate group and chromium trichloride group. The hepatic glycogen, glucose-6-phosphate dehydrogenase, glucokinase, Glut4, phosphor-AMPKβ1 and Akt levels in the high dose group were significantly higher than those of the model, chromium picolinate and chromium trichloride groups. Chromium malate in a high dose group can significantly increase high density lipoprotein cholesterol level while decreasing the total cholesterol, low density lipoprotein cholesterol and triglyceride levels when compared with chromium picolinate and chromium trichloride. The serum chromium content in chromium malate and chromium picolinate group is significantly higher than that of the chromium trichloride group. The results indicated that the curative effects of chromium malate on glycometabolism, glycometabolism-related enzymes and lipid metabolism changes are better than those of chromium picolinate and chromium trichloride. Chromium malate contributes to glucose uptake and transport in order to improved glycometabolism and glycometabolism-related enzymes.

Topics: Animals; Biological Transport; Blood Glucose; Body Weight; Chromium; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Dietary Supplements; Disease Models, Animal; Fasting; Gastrointestinal Microbiome; Glucose; Glycogen; Insulin; Lipid Metabolism; Liver; Malates; Male; Maze Learning; Rats

Lysosome-associated membrane protein-2 (LAMP-2) is the gene responsible for Danon disease, which is characterized by cardiomyopathy, autophagic vacuolar myopathy, and variable mental retardation. To elucidate the function of LAMP-2 in the central nervous system, we investigated the neuropathological changes in Lamp-2-deficient mice. Immunohistochemical observations revealed that Lamp-1 and cathepsin D-positive lysosomal structures increased in the large neurons of the mouse brain. Ubiquitin-immunoreactive aggregates and concanavalin A-positive materials were detected in these neurons. By means of ultrastructural studies, we found various-shaped accumulations, including lipofuscin, glycolipid-like materials, and membranous structures, in the neurons and glial cells of Lamp-2-deficient brains. In deficient mice, glycogen granules accumulated in hepatocyte lysosomes but were not observed in neurons. These pathological features indicate lysosomal storage disease; however, the findings are unlikely a consequence of deficiency of a single lysosomal enzyme. Although previous study results have shown a large amount of autophagic vacuoles in parenchymal cells of the visceral organs, these findings were rarely detected in the brain tissue except for some axons in the substantia nigra, in which abundant activated microglial cells with increased lipid peroxidation were observed. Thus, LAMP-2 in the central nervous system has a possible role in the degradation of the various macromolecules in lysosomes and an additional function concerning protection from oxidative stress, especially in the substantia nigra.

Topics: Animals; Disease Models, Animal; Glycogen; Lysosomal Storage Diseases; Lysosomal-Associated Membrane Protein 2; Lysosomes; Male; Mesencephalon; Mice; Mice, Knockout; Neurons

The hearts of mammalian hibernators maintain contractile function in the face of severe environmental stresses during winter heterothermy. To enable survival in torpor, hibernators regulate the expression of numerous genes involved in excitation-contraction coupling, metabolism, and stress response pathways. Understanding the basis of this transition may provide new insights into treatment of human cardiac disease. Few studies have investigated hibernator heart performance during both summer active and winter torpid states, and seasonal comparisons of whole heart function are generally lacking. We investigated the force-frequency relationship and the response to ex vivo ischemia-reperfusion in intact isolated hearts from 13-lined ground squirrels (Ictidomys tridecemlineatus) in the summer (active, July) and winter (torpid, January). In standard euthermic conditions, we found that winter hearts relaxed more rapidly than summer hearts at low to moderate pacing frequencies, even though systolic function was similar in both seasons. Proteome data support the hypothesis that enhanced Ca(2+) handling in winter torpid hearts underlies the increased relaxation rate. Additionally, winter hearts developed significantly less rigor contracture during ischemia than summer hearts, while recovery during reperfusion was similar in hearts between seasons. Winter torpid hearts have an increased glycogen content, which likely reduces development of rigor contracture during the ischemic event due to anaerobic ATP production. These cardioprotective mechanisms are important for the hibernation phenotype and highlight the resistance to hypoxic stress in the hibernator.

Topics: Adaptation, Physiological; Adenosine Triphosphate; Animals; Calcium Signaling; Cardiac Pacing, Artificial; Disease Models, Animal; Energy Metabolism; Female; Glycogen; Hibernation; Male; Muscle Proteins; Myocardial Contraction; Myocardial Reperfusion Injury; Myocardium; Phenotype; Proteomics; Sciuridae; Seasons; Time Factors; Ventricular Function, Left; Ventricular Pressure

End-stage liver diseases frequently require liver transplantation. Cell therapy could be an alternative. This study aimed to analyze whether undifferentiated mesenchymal stromal cells (U-MSCs) or MSC-derived hepatocyte-like cells (DHLCs) from adipose tissue (AT), umbilical cord blood (UCB) and bone marrow (BM) would better restore damaged liver.. AT was obtained from lipo-aspiration, UCB from an Umbilical Cord Blood Bank and BM from a BM Transplantation Unit. AT (collagenase digestion), UCB and BM (Ficoll gradient) were cultured (Dulbecco's modified Eagle's medium, low glucose, FBS) for 3 days. Detached adherent cells, at passage 4, were characterized as MSCs. Genetic stability was investigated by means of telomerase enzyme activity and karyotype. Hepatocyte differentiation protocol was performed with the use of Dulbecco's modified Eagle's medium, hepatocyte growth factor, basic fibroblast growth factor and nicotinamide (7 days); maturation medium (oncostatin, dexamethasone, insulin, transferrin and selenium) was added at 36 days. Hepatogenesis analyses were performed by use of morphology and albumin, AF, tyrosine-aminotransferase and glutamine synthetase gene expression and quantitative reverse transcription-polymerase chain reaction on days 9, 18, 25 and 36. Functionality was assessed through glycogen storage detection, indocyanine green absorption and transplantation procedure. U-MSCs and DHLCs were injected 48 h after induced fulminant hepatitis (intraperitoneal injection of carbon tetrachloride) in SCID/BALB-c mice. Histopathologic analyses were performed on days 7 and 15. Human origin included albumin and CK19 human markers.. All MSCs differentiated into functional hepatocyte-like cells, stored glycogen and absorbed indocyanine green. AT-MSC DHLC gene expression was more consistent with a normal hepatogenic-differentiation profile. UCB-MSCs expanded weakly, impairing their use for the transplantation procedure. AT and BM U-MSCs and DHLCs regenerated liver injury equally. Regenerated hepatocytes exhibited human origin.. AT might be the source and U-MSCS the stem cells useful for liver-regenerative therapy.

Topics: Adipose Tissue; Animals; Biomarkers; Bone Marrow Cells; Carbon Tetrachloride; Cell Differentiation; Cell- and Tissue-Based Therapy; Disease Models, Animal; Fetal Blood; Gene Expression; Glycogen; Hepatitis; Hepatocyte Growth Factor; Hepatocytes; Humans; Liver Failure, Acute; Liver Regeneration; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Mice; Mice, Inbred BALB C; Mice, SCID

Exopolysaccharides have a diverse set of functions in most bacteria including a mechanistic role in protecting bacteria against environmental stresses. Among the many functions attributed to the exopolysaccharides, biofilm formation, antibiotic resistance, immune evasion and colonization have been studied most extensively. The exopolysaccharide produced by many Gram positive as well as Gram negative bacteria including the oral pathogen Aggregatibacter actinomycetemcomitans is the homopolymer of β(1,6)-linked N-acetylglucosamine. Recently, we reported that the PGA-deficient mutant of A. actinomycetemcomitans failed to colonize or induce bone resorption in a rat model of periodontal disease, and the colonization genes, apiA and aae, were significantly down regulated in the mutant strain. To understand the role of exopolysaccharide and the pga locus in the global expression of A. actinomycetemcomitans, we have used comparative transcriptome profiling to identify differentially expressed genes in the wild-type strain in relation to the PGA-deficient strain. Transcriptome analysis revealed that about 50% of the genes are differently expressed (P < 0.05 and fold change >1.5). Our study demonstrated that the absence of the pga locus affects the genes involved in peptidoglycan recycling, glycogen storage, and virulence. Further, using confocal microscopy and plating assays, we show that the viability of pga mutant strain is significantly reduced during biofilm growth. Thus, this study highlights the importance of pga genes and the exopolysaccharide in the virulence of A. actinomycetemcomitans.

Topics: Aggregatibacter actinomycetemcomitans; Animals; Disease Models, Animal; Gene Expression Profiling; Gene Knockout Techniques; Genes, Bacterial; Glycogen; Metabolic Networks and Pathways; Pasteurellaceae Infections; Peptidoglycan; Periodontal Diseases; Polysaccharides, Bacterial; Rats; Stress, Physiological

Recently, there has been a growing interest in alternative therapies and in the therapeutic use of natural products for the treatment of diabetes. Therefore, in this study, we investigated the hypoglycemic and hypolipidemic effects of brown algae, Padina arborescens, in an animal model of type 2 diabetes. For 6 weeks, male C57BL/KsJ-db/db mice were administrated either control diet with no treatment or were treated with rosiglitazone (RG; 0.005%, w/w) or P. arborescens extract (PAE; 0.5%, w/w). At the end of the experimental period, the blood glucose levels, glycosylated hemoglobin levels, and plasma insulin levels were significantly lower in the RG and PAE groups compared with the control group. In addition, glucose tolerance was significantly improved in the RG and PAE groups. The homeostatic index of insulin resistance was lower in the RG and PAE groups than the diabetic control group. Also, the total cholesterol, LDL-cholesterol, triglyceride, and free fatty acid levels were lower in the PAE group than in the control group, whereas the HDL-C level was higher in the PAE group. Supplementation with PAE significantly lowered hepatic glucose-6-phosphatase and phosphoenolpyruvate carboxykinase activities, and increased glucokinase activity in the liver. Consequently, these results suggest that PAE may be beneficial in improving insulin resistance, hyperglycemia, and dyslipidemia in type 2 diabetics.

Topics: Adiponectin; Animals; Blood Glucose; Diabetes Mellitus, Type 2; Diet; Disease Models, Animal; Dyslipidemias; Fasting; Glucose Tolerance Test; Glycated Hemoglobin; Glycogen; Hyperglycemia; Hypoglycemic Agents; Insulin; Insulin Resistance; Lipids; Male; Mice; Mice, Inbred C57BL; Phaeophyceae; Rosiglitazone; Thiazolidinediones

Salvia libanotica (S. Libanotica) is a commonly used herb in folk medicine in Lebanon and the Middle East. The present study aimed to assess the scientific basis for the therapeutic use of S. libanotica in glycemia and to evaluate its effects on lipemia and abdominal fat.. Animals were fed a high-fat diet and allocated into a control and three experimental groups (GI, GII and GIII) receiving incremental doses of the plant water extract in drinking water (50, 150 and 450 mg/Kg body weight respectively) for six weeks.. The intake of S. libanotica extract was associated with a significant decrease in fasting serum glucose (102.9 ± 10.8 in GII and 87.5 ± 6.4 in GIII vs. 152.1 ± 7.9 mg/dl in controls) and a two fold increase in fasting serum insulin (GIII) and liver glycogen content (GII and GIII). Group III also had better glucose tolerance following intraperitoneal glucose challenges. Additionally, the plant extract intake produced a significant improvement in serum HDL (34.4 ± 2.4 in GIII vs. 27.2 ± 1.9 mg/dl in controls) and HDL/LDL cholesterol ratio (2.79 ± 0.32 in GII and 3.02 ± 0.31 in GIII vs. 1.74 ± 0.18 in controls), as well as a decrease in abdominal fat.. The current study is the first to demonstrate that the chronic intake of S. libanotica infusion helps in the prevention of high fat-induced hyperglycemia and dyslipidemia. This supports the plant use as a remedy for the prevention of type 2 diabetes and cardiovascular diseases.

Topics: Abdominal Fat; Alanine Transaminase; Alkaline Phosphatase; Animals; Blood Glucose; Body Weight; Diet, High-Fat; Disease Models, Animal; Glucose Tolerance Test; Glycogen; Insulin; Lipids; Liver; Male; Plant Extracts; Rats; Rats, Sprague-Dawley; Salvia

Hypoglycemia is a common adverse event and can injure central nervous system (CNS) white matter (WM). We determined whether glutamate receptors were involved in hypoglycemic WM injury.. Mouse optic nerves (MON), CNS WM tracts, were maintained at 37°C with oxygenated artificial cerebrospinal fluid (ACSF) containing 10mM glucose. Aglycemia was produced by switching to 0 glucose ACSF. Supramaximal compound action potentials (CAPs) were elicited using suction electrodes, and axon function was quantified as the area under the CAP. Amino acid release was measured using high-performance liquid chromatography. Extracellular lactate concentration ([lactate(-)]o) was measured using an enzyme electrode.. About 50% of MON axons were injured after 60 minutes of aglycemia (90% after 90 minutes); injury extent was not affected by animal age. Blockade of N-methyl-D-aspartate (NMDA)-type glutamate receptors improved recovery after 90 minutes of aglycemia by 250%. Aglycemic injury was increased by reducing [Mg(2+)]o or increasing [glycine]o , and decreased by lowering pHo , expected results for NMDA receptor-mediated injury. pHo increased during aglycemia due to a drop in [lactate(-)]o. Aglycemic injury was dramatically reduced in the absence of [Ca(2+)]o. Extracellular aspartate, a selective NMDA receptor agonist, increased during aglycemia ([glutamate]o fell).. Aglycemia injured WM by a unique excitotoxic mechanism involving NMDA receptors (located primarily on oligodendrocytes). During WM aglycemia, the selective NMDA agonist aspartate is released, probably from astrocytes. Injury is mediated by Ca(2+) influx through aspartate-activated NMDA receptors made permeable by an accompanying alkaline shift in pHo caused by a fall in [lactate(-)]o. These insights have important clinical implications.

Topics: alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; Animals; Aspartic Acid; Brain; Calcium; Disease Models, Animal; Excitatory Amino Acid Agonists; Excitatory Amino Acid Antagonists; Glutamic Acid; Glycine; Glycogen; Hydrogen-Ion Concentration; Hypoglycemia; Kynurenic Acid; Lactic Acid; Leukoencephalopathies; Mice; Mice, Inbred C57BL; Optic Nerve Injuries; Quinoxalines; Receptors, N-Methyl-D-Aspartate

Patients with pulmonary fibrosis often exhibit reduced lung function and diminished health-related quality of life. Studies have shown that paraquat-induced, extrapulmonary, acute lung injury affects the metabolic profile of glycogen content in different tissues. The purpose of the present study was to investigate whether the process of pulmonary fibrosis induced by continuous exposure to the toxic herbicide paraquat or by a local insult from bleomycin affects the glycogen content in tissues.. In the paraquat experiment, Wistar rats (n = 5 per group) received either saline (controls) or an intraperitoneal injection of a paraquat solution (7.0 mg/kg; experimental group) once a week for 4 weeks. In the bleomycin experiment, Balb/c mice (n = 5 per group) received either saline (controls) or 6.25 U/kg of bleomycin through intratracheal instillation in single dose (experimental group). Glycogen content in different tissues (mg/g tissue) was measured using the anthrone reagent. The lungs submitted to histopathological and quantitative analyses of fibrosis.. Paraquat-induced fibrosis led to lower glycogen content in the gastrocnemius muscle (2.7 ± 0.1 vs. 3.4 ± 0.1; 79 %) compared with the controls, whereas no changes in glycogen content were found in the diaphragm or heart. Bleomycin-induced fibrosis led to lower glycogen content in the diaphragm (0.43 ± 0.02 vs. 0.79 ± 0.09, 54 %), gastrocnemius muscle (0.62 ± 0.11 vs. 1.18 ± 0.06, 52 %), and heart (0.68 ± 0.11 vs. 1.39 ± 0.1, 49 %) compared with the controls (p < 0.05). Moreover, the area of fibrous connective tissue (μm(2)) in the lungs was significantly increased in paraquat-induced fibrosis (3,463 ± 377 vs. 565 ± 89) and bleomycin-induced fibrosis (3,707 ± 433.9 vs. 179 ± 51.28) compared with the controls.. The findings suggest that the effects of fibrogenesis in the lungs are not limited to local alterations but also lead to a reduction in glycogen content in the heart and other muscles. This reduction could partially explain the impaired muscle performance found in patients with pulmonary fibrosis.

Topics: Animals; Bleomycin; Diaphragm; Disease Models, Animal; Glycogen; Lung; Male; Mice; Mice, Inbred BALB C; Muscle, Skeletal; Myocardium; Paraquat; Pulmonary Fibrosis; Rats; Rats, Wistar

We found that the 50% aqueous EtOH extract of clove (Syzygium aromaticum) had potent dose-dependent inhibitory activity toward glycogen phosphorylase b and glucagon-stimulated glucose production in primary rat hepatocytes. Among the components, eugeniin inhibited glycogen phosphorylase b and glucagon-stimulated glucose production in primary rat hepatocytes, with IC50 values of 0.14 and 4.7 μM, respectively. In sharp contrast, eugenol showed no significant inhibition toward glycogen phosphorylase b, even at a concentration of 400 μM. Eugenol-reduced clove extracts (erCE) were prepared and when fed to a db/db mouse they clearly suppressed the blood glucose and HbA1c levels. Furthermore, plasma triglyceride and non-esterified fatty acid levels in 5% and 10% erCE-fed db/db mice were significantly lowered, compared with control db/db mice without erCE supplementation. These results suggested that dietary supplementation with the erCE could beneficially modify glucose and lipid metabolism and contribute to the prevention of the progress of hyperglycemia and metabolic syndrome.

Topics: Animals; Blood Glucose; Diabetes Mellitus, Type 2; Disease Models, Animal; Eugenol; Flowers; Glycated Hemoglobin; Glycogen; Glycogen Phosphorylase; Hepatocytes; Humans; Male; Mice; Mice, Inbred C57BL; Plant Extracts; Rats; Syzygium

Hyperthyroidism is known to increase food intake and central administration of thyroid hormone shows acute orexigenic effects in rodents. We investigated whether T3 influences appetite and glucose homeostasis by modulating circulating ghrelin, an important orexigenic hormone, in Zucker fatty rats. The acute anorectic effects of T3 and ghrelin mimetic MK-0677 were studied in rats trained for fasting induced food intake. The serum concentration of T3, ghrelin, glucose, triglycerides, and liver glycogen were estimated. The involvement of sympathetic nervous system was evaluated by conducting similar experiments in vagotomized rats. T3 increased food intake and glucose in rats over 4 h, with increase in serum T3 and decrease in liver glycogen. T3 treatment was associated with increase in serum ghrelin. An additive effect on appetite and glucose was observed when T3 (oral) was administered with central (intracerebroventricular) administration of a ghrelin mimetic, MK-0677. Ghrelin antagonist, compound 8a, antagonized the hyperglycemic and hyperphagic effects of T3. In vagotomized rats, T3 did not show increase in appetite as well as glucose. Serum ghrelin levels were unchanged in these animals after T3 treatment. However, T3 showed increase in serum triglyceride levels indicating its peripheral lipolytic effect, in vagotomized as well as sham treated animals. To conclude, acute orexigenic and hyperglycemic effects of T3 are associated with ghrelin secretion and activity. This effect seems to be mediated via vagus nerves, and is independent of glucoregulatory hormones.

Topics: Animals; Appetite Regulation; Blood Glucose; Disease Models, Animal; Eating; Feeding Behavior; Ghrelin; Glycogen; Homeostasis; Hyperphagia; Hyperthyroidism; Indoles; Injections, Intraperitoneal; Injections, Intraventricular; Liver; Male; Rats, Zucker; Spiro Compounds; Time Factors; Triglycerides; Triiodothyronine; Vagotomy; Vagus Nerve

Lafora disease is a fatal neurodegenerative condition characterized by the accumulation of abnormal glycogen inclusions known as Lafora bodies. It is an autosomal recessive disorder caused by mutations in either the laforin or malin gene. To study whether glycogen is primarily responsible for the neurodegeneration in Lafora disease, we generated malin knockout mice with impaired (totally or partially) glycogen synthesis. These animals did not show the increase in markers of neurodegeneration, the impairments in electrophysiological properties of hippocampal synapses, nor the susceptibility to kainate-induced epilepsy seen in the malin knockout model. Interestingly, the autophagy impairment that has been described in malin knockout animals was also rescued in this double knockout model. Conversely, two other mouse models in which glycogen is over-accumulated in the brain independently of the lack of malin showed impairment in autophagy. Our findings reveal that glycogen accumulation accounts for the neurodegeneration and functional consequences seen in the malin knockout model, as well as the impaired autophagy. These results identify the regulation of glycogen synthesis as a key target for the treatment of Lafora disease.

Topics: Animals; Autophagy; Biomarkers; Disease Models, Animal; Dual-Specificity Phosphatases; Electrical Synapses; Epilepsy; Glycogen; Glycogen Synthase; Hippocampus; Humans; Inclusion Bodies; Kainic Acid; Lafora Disease; Mice; Mice, Knockout; Mutation; Protein Tyrosine Phosphatases, Non-Receptor; Ubiquitin-Protein Ligases

AMP-activated protein kinase is a master regulator of cell metabolism and an attractive drug target for cancer and metabolic and cardiovascular diseases. Point mutations in the regulatory γ2-subunit of AMP-activated protein kinase (encoded by Prkag2 gene) caused a unique form of human cardiomyopathy characterized by cardiac hypertrophy, ventricular preexcitation, and glycogen storage. Understanding the disease mechanisms of Prkag2 cardiomyopathy is not only beneficial for the patients but also critical to the use of AMP-activated protein kinase as a drug target.. We sought to identify the pro-growth-signaling pathway(s) triggered by Prkag2 mutation and to distinguish it from the secondary response to glycogen storage.. In a mouse model of N488I mutation of the Prkag2 gene (R2M), we rescued the glycogen storage phenotype by genetic inhibition of glucose-6-phosphate-stimulated glycogen synthase activity. Ablation of glycogen storage eliminated the ventricular preexcitation but did not affect the excessive cardiac growth in R2M mice. The progrowth effect in R2M hearts was mediated via increased insulin sensitivity and hyperactivity of Akt, resulting in activation of mammalian target of rapamycin and inactivation of forkhead box O transcription factor-signaling pathways. Consequently, cardiac myocyte proliferation during the postnatal period was enhanced in R2M hearts followed by hypertrophic growth in adult hearts. Inhibition of mammalian target of rapamycin activity by rapamycin or restoration of forkhead box O transcription factor activity by overexpressing forkhead box O transcription factor 1 rescued the abnormal cardiac growth.. Our study reveals a novel mechanism for Prkag2 cardiomyopathy, independent of glycogen storage. The role of γ2-AMP-activated protein kinase in cell growth also has broad implications in cardiac development, growth, and regeneration.

Topics: AMP-Activated Protein Kinases; Animals; Cardiomyopathy, Hypertrophic, Familial; Cell Division; Cell Enlargement; Disease Models, Animal; Forkhead Box Protein O1; Forkhead Transcription Factors; Gene Knock-In Techniques; Genetic Complementation Test; Glucose-6-Phosphate; Glycogen; Glycogen Storage Disease; Glycogen Synthase; Insulin Resistance; Mice; Myocardium; Myocytes, Cardiac; Pre-Excitation Syndromes; Proto-Oncogene Proteins c-akt; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

We evaluated effects of chronic intracerebroventricular infusion of angiotensin (Ang)-(1-7) on cardiovascular and metabolic parameters in fructose-fed (FF) rats. After 6 weeks of fructose intake (10% in drinking water), Sprague-Dawley rats were subjected to intracerebroventricular infusion of Ang-(1-7) (200 ng/h; FF+A7 group) or 0.9% sterile saline (FF group) for 4 weeks with continued access to fructose. Compared with control rats, FF rats had increased mean arterial pressure and cardiac sympathetic tone with impaired baroreflex sensitivity. FF rats also presented increased circulating triglycerides, leptin, insulin, and glucose with impaired glucose tolerance. Furthermore, relative weights of liver and retroperitoneal adipose tissue were increased in FF rats. Glycogen content was reduced in liver, but increased in muscle. In contrast, fructose-fed rats subjected to chronic intracerebroventricular infusion of Ang-(1-7) presented reduced cardiac sympathetic tone with normalized mean arterial pressure, baroreflex sensitivity, glucose and insulin levels, and improved glucose tolerance. Relative weight of liver, and hepatic and muscle glycogen contents were also normalized in FF+A7 rats. In addition, FF+A7 rats had reduced mRNA expression for neuronal nitric oxide synthase and NR1 subunit of N-methyl-d-aspartate receptor in hypothalamus and dorsomedial medulla. Ang-(1-7) infusion did not alter fructose-induced hyperleptinemia and increased relative weight of retroperitoneal adipose tissue. There were no differences in body weights, neither in liver mRNA expression of phosphoenolpyruvate carboxykinase or glucose-6-phosphatase among the groups. These data indicate that chronic increase in Ang-(1-7) levels in the brain may have a beneficial role in fructose-fed rats by ameliorating cardiovascular and metabolic disorders.

Topics: Angiotensin I; Animals; Baroreflex; Blood Glucose; Blood Pressure; Body Weight; Brain; Dietary Carbohydrates; Disease Models, Animal; Fructose; Glycogen; Infusions, Intraventricular; Insulin; Metabolic Syndrome; Peptide Fragments; Rats; Rats, Sprague-Dawley; Risk Factors

Ischemic tissue is an environment with limited oxygen and nutrition availability. The poor retention of mesenchymal stem cells (MSC) in ischemic tissues greatly limits their therapeutic potential. The aim of this study was to determine whether and how inducible metabolic adaptation enhances MSC survival and therapy under ischemia.. MSC were subjected to glycogen synthase 1-specific small interfering RNA or vehicle treatment, and then sublethal hypoxic preconditioning (HP) was applied to induce glycogenesis. The treated cells were subjected to ischemic challenge. The results exhibited that HP of MSC induced glycogen storage and stimulated glycogen catabolism and cellular ATP production, thereby preserving cell viability in long-term ischemia. In vivo study using the mouse limb ischemia model transplanted with HP or control MSC into the ischemic thigh muscles revealed a significant increased retention of MSC with glycogen storage associated with improved limb salvage, perfusion recovery and angiogenesis in the ischemic muscles. In contrast, glycogen synthesis inhibition significantly abolished these improvements. Further molecular analysis indicated that phosphoinositide 3-kinase/AKT, hypoxia-inducible factor-1, and glycogen synthase kinase-3β regulated expression of glycogenesis genes, including glucose transporter 1, hexokinase, phosphoglucomutase 1, glycogen synthase 1, and glycogen phosphorylase, thereby regulating glycogen metabolism of stem cell during HP.. HP-induced glycogen storage improves MSC survival and therapy in ischemic tissues. Thus, inducible metabolic adaptation in stem cells may be considered as a novel strategy for potentiating stem cell therapy for ischemia.

Topics: Adaptation, Physiological; Adenosine Triphosphate; Animals; Cell Survival; Cells, Cultured; Disease Models, Animal; Energy Metabolism; Gene Expression Regulation, Enzymologic; Glycogen; Glycogen Synthase; Hindlimb; Hypoxia; Ischemia; Male; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Mice; Mice, Inbred C57BL; Muscle, Skeletal; Neovascularization, Physiologic; Recovery of Function; Regional Blood Flow; RNA Interference; Signal Transduction; Time Factors; Transfection

Fructose is a major diet component directly related to severe damages to the microcirculation and to diseases such as obesity, diabetes and hypertension to which physical activity is pointed out as an important non-pharmacological treatment since its positive effects precede anthropometric improvements. In this study we have investigated the effects of a light/moderate aerobic exercise training (AET) on microcirculatory dysfunction elicited by carbohydrate overload during a period of 5 months. Male hamsters (Mesocricetus auratus) whose drinking water was substituted (F) or not (C) by 10% fructose solution, during 20 weeks, associated or not to AET in the last 4 weeks (EC and EF subgroups) had their microcirculatory function evaluated on the cheek pouch preparation, glucose and insulin tolerance (GTT and ITT) tested. Arterial blood was collected for pO2, pCO2, HCO3(-), pH, total CO2, saturated O2 and lactate determinations. Liver fragments were observed using an electron microscope. Microcirculatory responses to acetylcholine [Ach, an endothelium-dependent vasodilator; 10(-8)M - *123.3±7.5% (C), 119.5±1.3% (EC), *98.1±3.2% (F) and 133.6±17.2% (EF); 10(-6)M - *133.0±4.1% (C), 135.6±4.3% (EC), *103.4±4.3% (F) and 134.1±5.9% (EF); 10(-4)M - *167.2±5.0% (C), 162.8±5.4% (EC), *123.8±6.3% (F) and 140.8±5.0% (EF)] and to sodium nitroprusside [SNP, an endothelium-independent vasodilator; 10(-8)M - 118.8±6.8% (C), 114.0±5.0% (EC), 100.2±2.9% (F), 104.9±4.4% (EF); 10(-6)M - 140.6±11.7% (C), 141.7±5.5% (EC), 125.0±4.7% (F), 138.3±2.8% (EF); 10(-4)M - 150.4±10.9% (C), 147.9±6.5% (EC), 139.2±7.3% (F), 155.9±4.7% (EF)] and macromolecular permeability increase induced by 30 min ischemia/reperfusion (I/R) procedure [14.4±3.5 (C), 30.0±1.9 (EC), *112.0±8.8 (F) and *22.4±0.9 leaks/cm(2) (EF)] have shown that endothelium-dependent vasodilatation was significantly reduced and I/R induced macromolecular permeability augmented in sedentary fructose (F) subgroup and both improved after AET. Electron microscopy analysis of the liver showed significant differences between exercised and sedentary subgroups with greater amount of glycogen in F subgroups compared to other ones. No significant changes on mean arterial pressure, heart rate or blood gase between subgroups could be detected. Our results point out that AET could normalize microcirculatory dysfunction elicited by long term substitution of drinking water by 10% fructose solution.

Topics: Animals; Biomarkers; Capillary Permeability; Cheek; Dietary Sucrose; Disease Models, Animal; Exercise Therapy; Glycogen; Liver; Male; Mesocricetus; Microcirculation; Microvessels; Reperfusion Injury; Time Factors; Vascular Diseases; Vasodilation; Vasodilator Agents

Glycogen storage disease type IIIa (GSD IIIa) is caused by a deficiency of the glycogen debranching enzyme (GDE), which is encoded by the Agl gene. GDE deficiency leads to the pathogenic accumulation of phosphorylase limit dextrin (PLD), an abnormal glycogen, in the liver, heart, and skeletal muscle. To further investigate the pathological mechanisms behind this disease and develop novel therapies to treat this disease, we generated a GDE-deficient mouse model by removing exons after exon 5 in the Agl gene. GDE reduction was confirmed by western blot and enzymatic activity assay. Histology revealed massive glycogen accumulation in the liver, muscle, and heart of the homozygous affected mice. Interestingly, we did not find any differences in the general appearance, growth rate, and life span between the wild-type, heterozygous, and homozygous affected mice with ad libitum feeding, except reduced motor activity after 50 weeks of age, and muscle weakness in both the forelimb and hind legs of homozygous affected mice by using the grip strength test at 62 weeks of age. However, repeated fasting resulted in decreased survival of the knockout mice. Hepatomegaly and progressive liver fibrosis were also found in the homozygous affected mice. Blood chemistry revealed that alanine transaminase (ALT), aspartate transaminase (AST) and alkaline phosphatase (ALP) activities were significantly higher in the homozygous affected mice than in both wild-type and heterozygous mice and the activity of these enzymes further increased with fasting. Creatine phosphokinase (CPK) activity was normal in young and adult homozygous affected mice. However, the activity was significantly elevated after fasting. Hypoglycemia appeared only at a young age (3 weeks) and hyperlipidemia was not observed in our model. In conclusion, with the exception of normal lipidemia, these mice recapitulate human GSD IIIa; moreover, we found that repeated fasting was detrimental to these mice. This mouse model will be useful for future investigation regarding the pathophysiology and treatment strategy of human GSD III.

Topics: Animals; Disease Models, Animal; Fasting; Female; Glycogen; Glycogen Debranching Enzyme System; Glycogen Storage Disease Type III; Humans; Immunoblotting; Liver; Male; Mice; Mice, Knockout; Muscle Strength; Organ Specificity

Duchenne muscular dystrophy (DMD) is a severe, genetic muscle wasting disorder characterised by progressive muscle weakness. DMD is caused by mutations in the dystrophin (dmd) gene resulting in very low levels or a complete absence of the dystrophin protein, a key structural element of muscle fibres which is responsible for the proper transmission of force. In the absence of dystrophin, muscle fibres become damaged easily during contraction resulting in their degeneration. DMD patients and mdx mice (an animal model of DMD) exhibit altered metabolic disturbances that cannot be attributed to the loss of dystrophin directly. We tested the hypothesis that glycogen metabolism is defective in mdx dystrophic mice.. Dystrophic mdx mice had increased skeletal muscle glycogen (79%, (P<0.01)). Skeletal muscle glycogen synthesis is initiated by glycogenin, the expression of which was increased by 50% in mdx mice (P<0.0001). Glycogen synthase activity was 12% higher (P<0.05) but glycogen branching enzyme activity was 70% lower (P<0.01) in mdx compared with wild-type mice. The rate-limiting enzyme for glycogen breakdown, glycogen phosphorylase, had 62% lower activity (P<0.01) in mdx mice resulting from a 24% reduction in PKA activity (P<0.01). In mdx mice glycogen debranching enzyme expression was 50% higher (P<0.001) together with starch-binding domain protein 1 (219% higher; P<0.01). In addition, mdx mice were glucose intolerant (P<0.01) and had 30% less liver glycogen (P<0.05) compared with control mice. Subsequent analysis of the enzymes dysregulated in skeletal muscle glycogen metabolism in mdx mice identified reduced glycogenin protein expression (46% less; P<0.05) as a possible cause of this phenotype.. We identified that mdx mice were glucose intolerant, and had increased skeletal muscle glycogen but reduced amounts of liver glycogen.

Topics: Animals; Cyclic AMP-Dependent Protein Kinases; Disease Models, Animal; Dystrophin; Glucose Intolerance; Glycogen; Glycogen Phosphorylase; Liver; Male; Mice; Mice, Inbred C57BL; Mice, Inbred mdx; Mice, Transgenic; Muscle, Skeletal; Phenotype

Different animal models have been used to study the effects of prenatal protein undernutrition and the mechanisms by which these occur. In mammals, the maternal diet is manipulated, exerting both direct nutritional and indirect hormonal effects. Chicken embryos develop independent from the hen in the egg. Therefore, in the chicken, the direct effects of protein deficiency by albumen removal early during incubation can be examined. Prenatal protein undernutrition was established in layer-type eggs by the partial replacement of albumen by saline at embryonic day 1 (albumen-deprived group), compared to a mock-treated sham and a non-treated control group. At hatch, survival of the albumen-deprived group was lower compared to the control and sham group due to increased early mortality by the manipulation. No treatment differences in yolk-free body weight or yolk weight could be detected. The water content of the yolk was reduced, whereas the water content of the carcass was increased in the albumen-deprived group, compared to the control group, indicating less uptake of nutrients from the yolk. At embryonic day 16, 20 and at hatch, plasma triiodothyronine (T3), corticosterone, lactate or glucose concentrations and hepatic glycogen content were not affected by treatment. At embryonic day 20, the plasma thyroxine (T4) concentrations of the albumen-deprived embryos was reduced compared to the control group, indicating a decreased metabolic rate. Screening for differential protein expression in the liver at hatch using two-dimensional difference gel electrophoresis revealed not only changed abundance of proteins important for amino acid metabolism, but also of enzymes related to energy and glucose metabolism. Interestingly, GLUT1, a glucose transporter, and PCK2 and FBP1, two out of three regulatory enzymes of the gluconeogenesis were dysregulated. No parallel differences in gene expressions causing the differences in protein abundance could be detected pointing to post-transcriptional or post-translational regulation of the observed differences.

Topics: Albumins; Amino Acids; Animals; Animals, Newborn; Avian Proteins; Chick Embryo; Chickens; Disease Models, Animal; Eggs; Electrophoresis, Gel, Two-Dimensional; Female; Fructose-Bisphosphatase; Gene Expression Regulation, Developmental; Glucose; Glucose Transporter Type 1; Glycogen; Humans; Kwashiorkor; Liver; Phosphoenolpyruvate Carboxykinase (ATP); Poultry Diseases; Reverse Transcriptase Polymerase Chain Reaction; Survival Analysis; Tandem Mass Spectrometry; Thyroxine

Khaya senegalensis A. Juss (Meliaceae) is commonly exploited for the traditional treatment of diabetes mellitus in Nigeria and Togo. The present study was conducted to examine the anti-diabetic activity of Khaya senegalensis butanol fraction (KSBF) of root ethanolic extract in a type 2 diabetes (T2D) model of rats.. T2D was induced in rats by feeding a 10% fructose solution ad libitum for two weeks followed by a single intraperitoneal injection of streptozotocin (40 mg/kg body weight) and the animals were treated with 150 and 300 mg/kg body weight (BW) of the fraction for five days in a week. Relevant diabetes-related parameters were analyzed in all experimental animals.. The KSBF treatment, at 300 mg/kg BW, significantly (p<0.05) reduced blood glucose level, improved oral glucose tolerance ability and β-cell function (HOMA-β), decreased insulin resistance (HOMA-IR), stimulated hepatic glycogen synthesis, ameliorated serum lipids alterations and prevented hepatic and renal damages compared to untreated diabetic rats. Additionally, the fraction insignificantly (p>0.05) improved weight gain, decreased food and fluid intake, stimulated insulin secretion and lowered serum fructosamine concentrations compared to untreated diabetic rats.. Data from this study suggests that orally administered KSBF, at 300 mg/kg BW, possess remarkable anti-type 2 diabetic activity and could ameliorate some diabetes-associated complications and hence can be considered as a source of potential anti-type 2 diabetic medicine.

Topics: Animals; Blood Glucose; Butanols; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Disease Models, Animal; Drinking; Drugs, Chinese Herbal; Eating; Glycogen; Hypoglycemic Agents; Insulin; Insulin Secretion; Insulin-Secreting Cells; Male; Meliaceae; Plant Roots; Rats; Rats, Sprague-Dawley; Streptozocin

Viral hepatitis resulting in chronic liver disease is an important clinical challenge and insight into the cellular processes that drive pathogenesis will be critical in order to develop new diagnostic and therapeutic options. Nuclear inclusions in viral and non-viral hepatitis are well documented and have diagnostic significance in some disease contexts. However, the origins and functional consequences of these nuclear inclusions remain elusive. To date the clinical observation of nuclear inclusions in viral and non-viral hepatitis has not been explored at depth in murine models of liver disease. Herein, we report that in a transgenic model of hepatitis B surface antigen mediated hepatitis, murine hepatocytes exhibit nuclear inclusions. Cells bearing nuclear inclusions were more likely to express markers of cell proliferation. We also established a correlation between these inclusions and oxidative stress. N-acetyl cysteine treatment effectively reduced oxidative stress levels, relieved endoplasmic reticulum (ER) stress, and the number of nuclear inclusions we observed in the transgenic mice. Our results suggest that the presence of nuclear inclusions in hepatocytes correlates with oxidative stress and cellular proliferation in a model of antigen mediated hepatitis.

Topics: Aldehydes; Animals; Biomarkers; Cell Death; Cell Nucleus; Cell Nucleus Size; Cellular Senescence; Disease Models, Animal; Endoplasmic Reticulum; Glycogen; Hepatitis; Hepatitis B Surface Antigens; Hepatocytes; Intranuclear Inclusion Bodies; Mice, Inbred C57BL; Mice, Transgenic; Oxidative Stress; Proliferating Cell Nuclear Antigen; Vacuoles

Insulin-mimetic species of low molecular weight are speculated to mediate some intracellular insulin actions. These inositol glycans, which are generated upon insulin stimulation from glycosylphosphatidylinositols, might control the activity of a multitude of insulin effector enzymes. Acylated inositol glycans (AIGs) are generated by cleavage of protein-free GPI precursors through the action of GPI-specific phospholipase C (GPI-PLC) and D (GPI-PLD). We synthesized AIGs (IG-1, IG-2, IG-13, IG-14, and IG-15) and then evaluated their insulin-mimicking bioactivities. IG-1 significantly stimulated glycogen synthesis and lipogenesis in 3T3-L1 adipocytes and rat isolated adipocytes dose-dependently. IG-2 significantly stimulated lipogenesis in rat isolated adipocytes dose-dependently. IG-15 also enhanced glycogen synthesis and lipogenesis in 3T3-L1 adipocytes. The administration of IG-1 decreased plasma glucose, increased glycogen content in liver and skeletal muscles and improved glucose tolerance in C57B6N mice with normal diets. The administration of IG-1 decreased plasma glucose in STZ-diabetic C57B6N mice. The treatment of IG-1 decreased plasma glucose, increased glycogen content in liver and skeletal muscles and improved glucose tolerance in C57B6N mice with high fat-diets and db/db mice. The long-term treatment of IG-1 decreased plasma glucose and reduced food intake and body weight in C57B6N mice with high fat-diets and ob/ob mice. Thus, IG-1 has insulin-mimicking bioactivities and improves glucose tolerance in mice models of diabetes with or without obesity.

Topics: 3T3-L1 Cells; Adipocytes; Animal Feed; Animals; Blood Glucose; Diabetes Mellitus, Experimental; Disease Models, Animal; Glycogen; Inositol; Insulin; Lipogenesis; Mice; Molecular Mimicry; Obesity; Polysaccharides; Rats; Time Factors

To explore effects of Shenqi preparation,Traditional Chinese Medicine, on anti-fatigue and anti-oxidant functions.. One hundred and twenty mice were randomly divided into control group and 3 experimental groups. The high, medium and low-dose of Shenqi preparation were given to the 3 experimental groups respectively, while distilled water to the control group for 15 d. The loaded swimming time, the level of lactate, serum urea nitrogen (SUN), muscle and liver glycogen, liver super-oxide dismutase (SOD), the content of malondialdehyde (MDA), glutathione peroxidase(GSH-Px) were assayed.. The loaded swimming test showed that the exhausted swimming time of 3 experimental groups [(296.0 +/- 25.3)s, (437.0 ĝ 38.9)s, (595.0 +/- 53.9)s respectively] was longer than that of control group [(231.0 +/- 22.5)s, P < 0.05, P < 0.01]. The liver glycogen content of the high and medium-dose experimental groups were higher than that of control group respectively (P < 0.01). The SUN content of each experimental group was less than that of the control group (P < 0.01, P < 0.05). Moreover,in the medium and high dose experimental groups, less accumulation of lactate was found (P < 0.01, P < 0.05), and the content of liver SOD and GSH-Px was higher (P < 0.01, P < 0.05). The content of liver MDA in high-dose experimental group was less than that of the control group (P < 0.05).. Shenqi preparation, especially the high and medium-dose experimental groups, is able to improve exercise tolerance and has anti-fatigue and anti-oxidant effects in mice.

Topics: Animals; Antioxidants; Blood Urea Nitrogen; Disease Models, Animal; Drugs, Chinese Herbal; Fatigue; Glutathione Peroxidase; Glycogen; Lactic Acid; Liver; Male; Malondialdehyde; Mice; Physical Conditioning, Animal; Superoxide Dismutase

Pompe disease is an inherited lysosomal storage disorder that results from a deficiency in acid α-glucosidase (GAA) activity due to mutations in the GAA gene. Pompe disease is characterized by accumulation of lysosomal glycogen primarily in heart and skeletal muscles, which leads to progressive muscle weakness. We have shown previously that the small molecule pharmacological chaperone AT2220 (1-deoxynojirimycin hydrochloride, duvoglustat hydrochloride) binds and stabilizes wild-type as well as multiple mutant forms of GAA, and can lead to higher cellular levels of GAA. In this study, we examined the effect of AT2220 on mutant GAA, in vitro and in vivo, with a primary focus on the endoplasmic reticulum (ER)-retained P545L mutant form of human GAA (P545L GAA). AT2220 increased the specific activity of P545L GAA toward both natural (glycogen) and artificial substrates in vitro. Incubation with AT2220 also increased the ER export, lysosomal delivery, proteolytic processing, and stability of P545L GAA. In a new transgenic mouse model of Pompe disease that expresses human P545L on a Gaa knockout background (Tg/KO) and is characterized by reduced GAA activity and elevated glycogen levels in disease-relevant tissues, daily oral administration of AT2220 for 4 weeks resulted in significant and dose-dependent increases in mature lysosomal GAA isoforms and GAA activity in heart and skeletal muscles. Importantly, oral administration of AT2220 also resulted in significant glycogen reduction in disease-relevant tissues. Compared to daily administration, less-frequent AT2220 administration, including repeated cycles of 4 or 5 days with AT2220 followed by 3 or 2 days without drug, respectively, resulted in even greater glycogen reductions. Collectively, these data indicate that AT2220 increases the specific activity, trafficking, and lysosomal stability of P545L GAA, leads to increased levels of mature GAA in lysosomes, and promotes glycogen reduction in situ. As such, AT2220 may warrant further evaluation as a treatment for Pompe disease.

Topics: 1-Deoxynojirimycin; Administration, Oral; Animals; Biocatalysis; Biological Availability; Chlorocebus aethiops; COS Cells; Disease Models, Animal; Endoplasmic Reticulum; Enzyme Stability; Gene Knockout Techniques; Glucan 1,4-alpha-Glucosidase; Glycogen; Glycogen Storage Disease Type II; Humans; Isoenzymes; Lysosomes; Mice; Mice, Transgenic; Mutant Proteins; Mutation; Protein Transport; Proteolysis

Pompe disease is due to a deficiency in acid-α-glucosidase (GAA) and results in debilitating skeletal muscle wasting, characterized by the accumulation of glycogen and autophagic vesicles. Given the role of lysosomes as a platform for mTORC1 activation, we examined mTORC1 activity in models of Pompe disease. GAA-knockdown C2C12 myoblasts and GAA-deficient human skin fibroblasts of infantile Pompe patients were found to have decreased mTORC1 activation. Treatment with the cell-permeable leucine analog L-leucyl-L-leucine methyl ester restored mTORC1 activation. In vivo, Pompe mice also displayed reduced basal and leucine-stimulated mTORC1 activation in skeletal muscle, whereas treatment with a combination of insulin and leucine normalized mTORC1 activation. Chronic leucine feeding restored basal and leucine-stimulated mTORC1 activation, while partially protecting Pompe mice from developing kyphosis and the decline in muscle mass. Leucine-treated Pompe mice showed increased spontaneous activity and running capacity, with reduced muscle protein breakdown and glycogen accumulation. Together, these data demonstrate that GAA deficiency results in reduced mTORC1 activation that is partly responsible for the skeletal muscle wasting phenotype. Moreover, mTORC1 stimulation by dietary leucine supplementation prevented some of the detrimental skeletal muscle dysfunction that occurs in the Pompe disease mouse model.

Topics: alpha-Glucosidases; Animals; Cell Line; Dietary Supplements; Dipeptides; Disease Models, Animal; Dose-Response Relationship, Drug; Fibroblasts; Glycogen; Glycogen Storage Disease Type II; Humans; Insulin; Kyphosis; Lysosomes; Mechanistic Target of Rapamycin Complex 1; Mice, Inbred C57BL; Mice, Knockout; Motor Activity; Multiprotein Complexes; Muscle, Skeletal; Muscular Atrophy; Myoblasts; RNA Interference; TOR Serine-Threonine Kinases; Transfection

Recent data indicate that there is a link between depression and diabetes and that excess glucocorticoids may play an underlying role in the pathogenesis of both of these diseases. The aim of the present study was to determine whether there are any alterations in glucose, glycogen, glucose transporters, insulin, insulin receptors or corticosterone concentrations in the hippocampus and frontal cortex in a prenatal stress rat model of depression.. Male rats whose mothers had been subjected to stress and control animals were subjected to the Porsolt test to verify the experimental model. Next, some of the rats were subjected to acute stress and/or were administered glucose. Glucose, glycogen, corticosterone, insulin, insulin receptor, phospho-insulin receptor and glucose transporter (GLUT1, GLUT3 and GLUT4) concentrations were assayed.. Prenatally stressed rats exhibited glucose and glycogen concentrations in both investigated brain structures that exceeded those of the control animals. Prenatal stress also increased the levels of glucose transporters - GLUT1 in both tissues and GLUT4 in the frontal cortex. The changes in the prenatally stressed rats were more prominent in the animals that were subjected to stress or glucose loading in adulthood.. The increase in carbohydrate brain concentrations evoked by prenatal stress may result from changes in the amounts of glucose transporters, especially GLUT1. Moreover, the obtained results support the hypothesis that stress during the perinatal period permanently increases the sensitivity of brain tissue to factors that act in adulthood. © 2014 S. Karger AG, Basel.

Topics: Animals; Brain; Corticosterone; Depressive Disorder; Disease Models, Animal; Female; Glucose; Glucose Transporter Type 1; Glucose Transporter Type 3; Glucose Transporter Type 4; Glycogen; Insulin; Male; Pregnancy; Prenatal Exposure Delayed Effects; Random Allocation; Rats, Sprague-Dawley; Receptor, Insulin; Stress, Psychological

Poor skeletal muscle performance was shown to strongly predict mortality and long-term prognosis in a variety of diseases, including heart failure (HF). Despite the known benefits of aerobic exercise training (AET) in improving the skeletal muscle phenotype in HF, the optimal exercise intensity to elicit maximal outcomes is still under debate. Therefore, the aim of the present study was to compare the effects of high-intensity AET with those of a moderate-intensity protocol on skeletal muscle of infarcted rats. Wistar rats underwent myocardial infarction (MI) or sham surgery. MI groups were submitted either to an untrained (MI-UNT); moderate-intensity (MI-CMT, 60% Vo(2)(max)); or matched volume, high-intensity AET (MI-HIT, intervals at 85% Vo(2)(max)) protocol. High-intensity AET (HIT) was superior to moderate-intensity AET (CMT) in improving aerobic capacity, assessed by treadmill running tests. Cardiac contractile function, measured by echocardiography, was equally improved by both AET protocols. CMT and HIT prevented the MI-induced decay of skeletal muscle citrate synthase and hexokinase maximal activities, and increased glycogen content, without significant differences between protocols. Similar improvements in skeletal muscle redox balance and deactivation of the ubiquitin-proteasome system were also observed after CMT and HIT. Such intracellular findings were accompanied by prevented skeletal muscle atrophy in both MI-CMT and MI-HIT groups, whereas no major differences were observed between protocols. Taken together, our data suggest that despite superior effects of HIT in improving functional capacity, skeletal muscle adaptations were remarkably similar among protocols, leading to the conclusion that skeletal myopathy in infarcted rats was equally prevented by either moderate-intensity or high-intensity AET.

Topics: Animals; Citrate (si)-Synthase; Disease Models, Animal; Exercise Therapy; Exercise Tolerance; Glycogen; Hexokinase; Male; Muscle Contraction; Muscle, Skeletal; Muscular Atrophy; Myocardial Contraction; Myocardial Infarction; Myocardium; Oxidation-Reduction; Oxygen Consumption; Proteasome Endopeptidase Complex; Rats; Rats, Wistar; Ultrasonography

Pompe disease, also known as glycogen storage disease (GSD) type II, is caused by deficiency of lysosomal acid α-glucosidase (GAA). The resulting glycogen accumulation causes a spectrum of disease severity ranging from a rapidly progressive course that is typically fatal by 1 to 2 years of age to a slower progressive course that causes significant morbidity and early mortality in children and adults. The aim of this study is to better understand the biochemical consequences of glycogen accumulation in the Pompe mouse. We evaluated glycogen metabolism in heart, triceps, quadriceps, and liver from wild type and several strains of GAA(-/-) mice. Unexpectedly, we observed that lysosomal glycogen storage correlated with a robust increase in factors that normally promote glycogen biosynthesis. The GAA(-/-) mouse strains were found to have elevated glycogen synthase (GS), glycogenin, hexokinase, and glucose-6-phosphate (G-6-P, the allosteric activator of GS). Treating GAA(-/-) mice with recombinant human GAA (rhGAA) led to a dramatic reduction in the levels of glycogen, GS, glycogenin, and G-6-P. Lysosomal glycogen storage also correlated with a dysregulation of phosphorylase, which normally breaks down cytoplasmic glycogen. Analysis of phosphorylase activity confirmed a previous report that, although phosphorylase protein levels are identical in muscle lysates from wild type and GAA(-/-) mice, phosphorylase activity is suppressed in the GAA(-/-) mice in the absence of AMP. This reduction in phosphorylase activity likely exacerbates lysosomal glycogen accumulation. If the dysregulation in glycogen metabolism observed in the mouse model of Pompe disease also occurs in Pompe patients, it may contribute to the observed broad spectrum of disease severity.

Topics: alpha-Glucosidases; Animals; Disease Models, Animal; Gene Deletion; Glucosyltransferases; Glycogen; Glycogen Phosphorylase; Glycogen Storage Disease Type II; Glycogen Synthase; Glycoproteins; Hexokinase; Humans; Liver; Mice; Mice, Inbred C57BL; Myocardium; Quadriceps Muscle; Recombinant Proteins

This study explores the hypoglycemic effects of borapetoside A, the most active principle among three major diterpenoids (borapetosides A, B, and C) isolated from ethanol extract of Tinospora crispa vines.. We employed mouse mitogenic C2C12 and hepatocellular carcinoma Hep3B cells in this study. Furthermore, the mice were divided into three groups, including streptozotocin-induced type 1 diabetes mellitus, diet-induced type 2 diabetes mellitus, and normal control. The mice in each group were treated with assigned vehicle control, borapetoside A, or other active agents.. Borapetoside A was shown to increase the glycogen content and decrease the plasma glucose concentration in a concentration or dose-dependent manner in vitro and in vivo. The hypoglycemic effects in the normal mice and the mice with type 2 diabetes mellitus were associated with the increases of the plasma insulin levels; whereas, the insulin levels remained unchanged in the mice with type 1 diabetes mellitus. Borapetoside A not only attenuated the elevation of plasma glucose induced by an intraperitoneal glucose tolerance test, but also increased the glycogen synthesis of IL-6 treated C2C12 cells. Moreover, the elevated protein expression levels of phosphoenolpyruvate carboxykinase were reversed after borapetoside A treatment twice a day for 7 days.. The hypoglycemic effects of borapetoside A were mediated through both the insulin-dependent and the insulin-independent pathways. Furthermore, borapetoside A was shown to increase the glucose utilization in peripheral tissues, to reduce the hepatic gluconeogenesis, and to activate the insulin signaling pathway; they thereby contributed to the lowering of the plasma glucose. Comparison of the structures of three borapetosides suggests clearly that the C-8 stereochemistry plays a key role in hypoglycemic effect since the active borapetoside A and C possess 8R-chirality but the inactive borapetoside B possess 8S-chirality. The location of glycoside at C-3 for borapetoside A but C-6 for borapetoside C and the formation of lactone between C-4 and C-6 for borapetoside A, could account for the different potency in hypoglycemic action for these two compounds.

Topics: Animals; Blood Glucose; Cell Line; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Disease Models, Animal; Diterpenes; Gluconeogenesis; Glucose; Glucosides; Glycogen; Hypoglycemic Agents; Insulin; Interleukin-6; Liver; Male; Mice; Mice, Inbred ICR; Muscles; Phosphoenolpyruvate Carboxykinase (GTP); Phytotherapy; Plant Extracts; Plants, Medicinal; Signal Transduction; Tinospora

The Spontaneously Hypertensive Heart Failure (SHHF) rat mimics the human progression of hypertension from hypertrophy to heart failure. However, it is unknown whether SHHF animals can exercise at sufficient levels to observe beneficial biochemical adaptations in skeletal muscle. Thirty-seven female SHHF and Wistar-Furth (WF) rats were randomized to sedentary (SHHFsed and WFsed) and exercise groups (SHHFex and WFex). The exercise groups had access to running wheels from 6-22 months of age. Hindlimb muscles were obtained for metabolic measures that included mitochondrial enzyme function and expression, and glycogen utilization. The SHHFex rats ran a greater distance and duration as compared to the WFex rats (P<0.05), but the WFex rats ran at a faster speed (P<0.05). Skeletal muscle citrate synthase and beta-hydroxyacyl-CoA dehydrogenase enzyme activity was not altered in the SHHFex group, but was increased (P<0.05) in the WFex animals. Citrate synthase protein and gene expression were unchanged in SHHFex animals, but were increased in WFex rats (P<0.05). In the WFex animals muscle glycogen was significantly depleted after exercise (P<0.05), but not in the SHHFex group. We conclude that despite robust amounts of aerobic activity, voluntary wheel running exercise was not sufficiently intense to improve the oxidative capacity of skeletal muscle in adult SHHF animals, indicating an inability to compensate for declining heart function by improving peripheral oxidative adaptations in the skeletal muscle.

Topics: 3-Hydroxyacyl CoA Dehydrogenases; Adaptation, Physiological; Animals; ATP Citrate (pro-S)-Lyase; Disease Models, Animal; Energy Metabolism; Female; Glycogen; Glycolysis; Heart Failure; Hindlimb; Hypertension; Muscle Contraction; Muscle, Skeletal; Physical Exertion; Rats; Rats, Inbred SHR; Rats, Inbred WF; RNA, Messenger; Running; Time Factors

A recently proposed therapeutic approach for lysosomal storage disorders (LSDs) relies upon the ability of transcription factor EB (TFEB) to stimulate autophagy and induce lysosomal exocytosis leading to cellular clearance. This approach is particularly attractive in glycogen storage disease type II [a severe metabolic myopathy, Pompe disease (PD)] as the currently available therapy, replacement of the missing enzyme acid alpha-glucosidase, fails to reverse skeletal muscle pathology. PD, a paradigm for LSDs, is characterized by both lysosomal abnormality and dysfunctional autophagy. Here, we show that TFEB is a viable therapeutic target in PD: overexpression of TFEB in a new muscle cell culture system and in mouse models of the disease reduced glycogen load and lysosomal size, improved autophagosome processing, and alleviated excessive accumulation of autophagic vacuoles. Unexpectedly, the exocytosed vesicles were labelled with lysosomal and autophagosomal membrane markers, suggesting that TFEB induces exocytosis of autophagolysosomes. Furthermore, the effects of TFEB were almost abrogated in the setting of genetically suppressed autophagy, supporting the role of autophagy in TFEB-mediated cellular clearance.

Topics: Adenoviridae; alpha-Glucosidases; Animals; Autophagy; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; Cells, Cultured; Disease Models, Animal; Exocytosis; Genetic Vectors; Glycogen; Glycogen Storage Disease Type II; Lysosomes; Mice; Mice, Knockout; Muscle, Skeletal

The translation of genes encoded in the mitochondrial genome requires specific machinery that functions in the organelle. Among the many mutations linked to human disease that affect mitochondrial translation, several are localized to nuclear genes coding for mitochondrial aminoacyl-transfer RNA synthetases. The molecular significance of these mutations is poorly understood, but it is expected to be similar to that of the mutations affecting mitochondrial transfer RNAs. To better understand the molecular features of diseases caused by these mutations, and to improve their diagnosis and therapeutics, we have constructed a Drosophila melanogaster model disrupting the mitochondrial seryl-tRNA synthetase by RNA interference. At the molecular level, the knockdown generates a reduction in transfer RNA serylation, which correlates with the severity of the phenotype observed. The silencing compromises viability, longevity, motility and tissue development. At the cellular level, the knockdown alters mitochondrial morphology, biogenesis and function, and induces lactic acidosis and reactive oxygen species accumulation. We report that administration of antioxidant compounds has a palliative effect of some of these phenotypes. In conclusion, the fly model generated in this work reproduces typical characteristics of pathologies caused by mutations in the mitochondrial aminoacylation system, and can be useful to assess therapeutic approaches.

Topics: Animals; Antioxidants; Cell Respiration; Disease Models, Animal; Drosophila melanogaster; Glycogen; Humans; Lactic Acid; Locomotion; Longevity; Mitochondria; Mitochondrial Diseases; Protein Biosynthesis; Reactive Oxygen Species; RNA Interference; Serine-tRNA Ligase; Transfer RNA Aminoacylation

Previous studies strongly suggest that starch binding domain containing protein 1 (Stbd1) plays an important role in intracellular glycogen trafficking into lysosomes. We report here that Stbd1 expression is markedly increased in skeletal muscles but not in heart and liver of GAA-KO mice. An AAV2/9 vector expressing a Stbd1-specific shRNA effectively suppressed Stbd1 expression but did not alter lysosomal glycogen accumulation in the affected tissues of GAA-KO mice. Our results indicate that inhibition of Stbd1 does not appear to be an effective therapeutic approach for Pompe disease.

Topics: Animals; Cell Line; Disease Models, Animal; Gene Expression Regulation; Gene Knockdown Techniques; Glycogen; Glycogen Storage Disease Type II; Humans; Lysosomes; Membrane Proteins; Mice; Mice, Knockout; Muscle Proteins; Muscle, Skeletal; RNA Interference

To investigate the protective effects of ischemic pre and postconditioning, as well as the association of both methods, in skeletal muscle injury produced by ischemia and reperfusion in rats.. An experimental study was designed using 40 Wistar rats divided in four groups (n=10): Control - rats submitted to ischemia for 240 minutes (min) and reperfusion for 60 min; Ischemic preconditioning (Pre) - animals submitted to three cycles of clamping and releasing the aorta for five min before being submitted to the ischemia/reperfusion procedure; Ischemic postconditioning (Post) - rats submitted to three cycles of clamping and releasing the aorta for one min after the 240-minute ischemic phase; Ischemic pre and postconditioning (Pre-post) - animals submitted to the same procedures of Pre and Post groups. Skeletal muscle injury was evaluated by measuring serum levels of aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and creatine phosphokinase (CPK); and muscular levels of malondialdehyde (MDA) and glycogen.. AST levels were significantly higher in Pre and Pre-post groups (P<.01). There were no differences in LDH and CPK levels. Muscular MDA levels were similar. Glycogen levels were significantly higher in Pre and Pre-post groups (P<.01).. Both preconditioning and its association with postconditioning had a protective effect by avoiding glycogen depletion in skeletal muscle in rats submitted to ischemia and reperfusion. Association of pre and postconditioning did not show advantage compared to preconditioning alone. Postconditioning alone did not show protective effect.

Topics: Animals; Aspartate Aminotransferases; Creatine Kinase; Disease Models, Animal; Glycogen; Ischemic Postconditioning; Ischemic Preconditioning; L-Lactate Dehydrogenase; Male; Malondialdehyde; Muscle, Skeletal; Random Allocation; Rats; Rats, Wistar; Reperfusion Injury; Reproducibility of Results; Time Factors

Metabolic dysfunction is an important modulator of disease course in amyotrophic lateral sclerosis (ALS). We report here that a familial mouse model (transgenic mice over-expressing the G93A mutation of the Cu/Zn superoxide dismutase 1 gene) of ALS enters a progressive state of acidosis that is associated with several metabolic (hormonal) alternations that favor lipolysis. Extensive investigation of the major determinants of H(+) concentration (i.e., the strong ion difference and the strong ion gap) suggests that acidosis is also due in part to the presence of an unknown anion. Consistent with a compensatory response to avert pathological acidosis, ALS mice harbor increased accumulation of glycogen in CNS and visceral tissues. The altered glycogen is associated with fluctuations in lysosomal and neutral α-glucosidase activities. Disease-related changes in glycogen, glucose, and α-glucosidase activity are also found in spinal cord tissue samples of autopsied patients with ALS. Collectively, these data provide insights into the pathogenesis of ALS as well as potential targets for drug development.

Topics: Acidosis; Amyotrophic Lateral Sclerosis; Animals; Disease Models, Animal; Disease Progression; Glycogen; Humans; Mice; Mice, Transgenic; Mutation; Superoxide Dismutase

Insulin rapidly suppresses hepatic glucose production and slowly decreases expression of genes encoding gluconeogenic proteins. In this study, we show that an immediate effect of insulin is to redirect newly synthesized glucose-6-phosphate to glycogen without changing the rate of gluconeogenesis. This process requires hepatic Akt2, as revealed by blunted insulin-mediated suppression of glycogenolysis in the perfused mouse liver, elevated hepatic glucose production during a euglycemic-hyperinsulinemic clamp, or diminished glycogen accumulation during clamp or refeeding in mice without hepatic Akt2. Surprisingly, the absence of Akt2 disrupted glycogen metabolism independent of GSK3α and GSK3β phosphorylation, which is thought to be an essential step in the pathway by which insulin regulates glycogen synthesis through Akt. These data show that (1) the immediate action of insulin to suppress hepatic glucose production functions via an Akt2-dependent redirection of glucose-6-phosphate to glycogen, and (2) insulin increases glucose phosphorylation and conversion to glycogen independent of GSK3.

Topics: Animals; Disease Models, Animal; Glucose Clamp Technique; Glucose-6-Phosphate; Glycogen; Glycogen Synthase Kinase 3; Glycogenolysis; Hyperinsulinism; Insulin; Liver; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Postprandial Period; Proto-Oncogene Proteins c-akt; Signal Transduction

Lafora disease (LD) is a fatal progressive myoclonus epilepsy characterized neuropathologically by aggregates of abnormally structured glycogen and proteins (Lafora bodies [LBs]), and neurodegeneration. Whether LBs could be prevented by inhibiting glycogen synthesis and whether they are pathogenic remain uncertain. We genetically eliminated brain glycogen synthesis in LD mice. This resulted in long-term prevention of LB formation, neurodegeneration, and seizure susceptibility. This study establishes that glycogen synthesis is requisite for LB formation and that LBs are pathogenic. It opens a therapeutic window for potential treatments in LD with known and future small molecule inhibitors of glycogen synthesis.

Topics: Animals; Disease Models, Animal; Dual-Specificity Phosphatases; Gene Knockout Techniques; Glycogen; Glycogen Synthase; Lafora Disease; Mice; Mice, 129 Strain; Mice, Inbred C57BL; Mice, Knockout; Protein Tyrosine Phosphatases, Non-Receptor

Fatty acid and glucose transporters translocate between the sarcolemma and intracellular compartments to regulate substrate metabolism acutely. We hypothesised that during ischemia fatty acid translocase (FAT/CD36) would translocate away from the sarcolemma to limit fatty acid uptake when fatty acid oxidation is inhibited.. Wistar rat hearts were perfused during preischemia, low-flow ischemia, and reperfusion, using (3)H-substrates for measurement of metabolic rates, followed by metabolomic analysis and subcellular fractionation. During ischemia, there was a 32% decrease in sarcolemmal FAT/CD36 accompanied by a 95% decrease in fatty acid oxidation rates, with no change in intramyocardial lipids. Concomitantly, the sarcolemmal content of the glucose transporter, GLUT4, increased by 90% during ischemia, associated with an 86% increase in glycolytic rates, 45% decrease in glycogen content, and a 3-fold increase in phosphorylated AMP-activated protein kinase. Following reperfusion, decreased sarcolemmal FAT/CD36 persisted, but fatty acid oxidation rates returned to preischemic levels, resulting in a 35% decrease in myocardial triglyceride content. Elevated sarcolemmal GLUT4 persisted during reperfusion; in contrast, glycolytic rates decreased to 30% of preischemic rates, accompanied by a 5-fold increase in intracellular citrate levels and restoration of glycogen content.. During ischemia, FAT/CD36 moved away from the sarcolemma as GLUT4 moved toward the sarcolemma, associated with a shift from fatty acid oxidation to glycolysis, while intramyocardial lipid accumulation was prevented. This relocation was maintained during reperfusion, which was associated with replenishing glycogen stores as a priority, occurring at the expense of glycolysis and mediated by an increase in citrate levels.

Topics: Animals; CD36 Antigens; Disease Models, Animal; Energy Metabolism; Fatty Acids; Glucose Transporter Type 4; Glycogen; Glycolysis; Male; Metabolomics; Myocardial Ischemia; Myocardial Reperfusion; Myocardium; Oxidation-Reduction; Protein Transport; Rats; Rats, Wistar; Sarcolemma; Subcellular Fractions

Monosodium glutamate (MSG) is a commonly used food enhancer. Glutamate is used as food additive for enhancing the "meat flavor" of food and gives a particular taste named "umami". In this study, we evaluated the effect of vitamin C on monosodium glutamate induced rat liver injury. This study was divided into 3 groups: group 1 received a diet containing 0.9% NaCl; group 2 received diet containing MSG 6 mg/g/b.w.; and group 3 received a diet containing 6 mg/g/b.w. followed by vitamin C (500 mg/kg/b.w.) for 45 days. The resulting changes were detected using histological, histochemical, ultrastructural, and immuohistochemical analysis. Severe alterations were recorded including dilatations of the central veins; severe cyto-architectural distortions of the hepatocytes; marked reduction in both carbohydrates and proteins; vacuolated cytoplasm, swollen mitochondria and vesiculated rough endoplasmic reticulum with picknotic nuclei; in addition to significant variation in the expression of ki-67 and p53 proteins. The data obtained from this study showed the improvements in the pathological architecture of the liver after treatment with vitamin C. The present data point to the ameliorative effect of vitamin C against MSG induced liver injury.

Topics: Animals; Antioxidants; Ascorbic Acid; Chemical and Drug Induced Liver Injury; Collagen; Disease Models, Animal; Glycogen; Immunohistochemistry; Ki-67 Antigen; Liver; Male; Microscopy, Electron, Transmission; Rats; Sodium Glutamate; Tumor Suppressor Protein p53

Air pollution is a global challenge to public health. Epidemiological studies have linked exposure to ambient particulate matter with aerodynamic diameters<2.5 μm (PM(2.5)) to the development of metabolic diseases. In this study, we investigated the effect of PM(2.5) exposure on liver pathogenesis and the mechanism by which ambient PM(2.5) modulates hepatic pathways and glucose homeostasis.. Using "Ohio's Air Pollution Exposure System for the Interrogation of Systemic Effects (OASIS)-1", we performed whole-body exposure of mice to concentrated ambient PM(2.5) for 3 or 10 weeks. Histological analyses, metabolic studies, as well as gene expression and molecular signal transduction analyses were performed to determine the effects and mechanisms by which PM(2.5) exposure promotes liver pathogenesis.. Mice exposed to PM(2.5) for 10 weeks developed a non-alcoholic steatohepatitis (NASH)-like phenotype, characterized by hepatic steatosis, inflammation, and fibrosis. After PM(2.5) exposure, mice displayed impaired hepatic glycogen storage, glucose intolerance, and insulin resistance. Further investigation revealed that exposure to PM(2.5) led to activation of inflammatory response pathways mediated through c-Jun N-terminal kinase (JNK), nuclear factor kappa B (NF-κB), and Toll-like receptor 4 (TLR4), but suppression of the insulin receptor substrate 1 (IRS1)-mediated signaling. Moreover, PM(2.5) exposure repressed expression of the peroxisome proliferator-activated receptor (PPAR)γ and PPARα in the liver.. Our study suggests that PM(2.5) exposure represents a significant "hit" that triggers a NASH-like phenotype and impairs hepatic glucose metabolism. The information from this work has important implications in our understanding of air pollution-associated metabolic disorders.

Topics: Animals; Disease Models, Animal; Fatty Liver; Glucose; Glucose Intolerance; Glycogen; Hepatitis; Homeostasis; Inhalation Exposure; Insulin; Insulin Receptor Substrate Proteins; Insulin Resistance; JNK Mitogen-Activated Protein Kinases; Liver; Liver Cirrhosis; Male; Mice; Mice, Inbred C57BL; NF-kappa B; Non-alcoholic Fatty Liver Disease; Particulate Matter; Phenotype; PPAR alpha; PPAR gamma; Signal Transduction; Toll-Like Receptor 4

In this study, we evaluated the effect of an analogue of l-carnitine on parameters involved with Metabolic Syndrome in obese Zucker rats. Twenty-four rats were treated for 5 weeks with l-carnitine (300 mg/kg) and its analogue at two concentrations (100 and 250 mg/kg) to assess their impact on glucose, triglycerides and cholesterol in liver and blood samples, as well as the amount of liver glycogen. Liver slices were also analysed. The analogue reduced the levels of glucose, triglycerides and cholesterol in liver and the level of triglycerides in serum. At 100 mg/kg, the analogue proved more effective than l-carnitine in improving the biochemical alterations present in liver. The amount of liver glycogen content was higher in obese animals treated with both l-carnitine and the analogue. No changes on insulin and leptin were observed in animals treated. l-carnitine and its analogue reduced the microvesicular fatty infiltration in liver. This study demonstrated that the analogue tested is more potent and efficient than l-carnitine and improves the pharmacological profile of l-carnitine.

Topics: Animals; Carnitine; Cholesterol; Disease Models, Animal; Dose-Response Relationship, Drug; Glucose; Glycogen; Insulin; Leptin; Liver; Male; Metabolic Syndrome; Obesity; Rats; Rats, Zucker; Triglycerides

We have used a peptide-based targeting system to improve lysosomal delivery of acid α-glucosidase (GAA), the enzyme deficient in patients with Pompe disease. Human GAA was fused to the glycosylation-independent lysosomal targeting (GILT) tag, which contains a portion of insulin-like growth factor II, to create an active, chimeric enzyme with high affinity for the cation-independent mannose 6-phosphate receptor. GILT-tagged GAA was taken up by L6 myoblasts about 25-fold more efficiently than was recombinant human GAA (rhGAA). Once delivered to the lysosome, the mature form of GILT-tagged GAA was indistinguishable from rhGAA and persisted with a half-life indistinguishable from rhGAA. GILT-tagged GAA was significantly more effective than rhGAA in clearing glycogen from numerous skeletal muscle tissues in the Pompe mouse model. The GILT-tagged GAA enzyme may provide an improved enzyme replacement therapy for Pompe disease patients.

Topics: Animals; Biological Transport; Disease Models, Animal; Drug Delivery Systems; Enzyme Replacement Therapy; Glucan 1,4-alpha-Glucosidase; Glycogen; Glycogen Storage Disease Type II; Glycosylation; Half-Life; HEK293 Cells; Humans; Insulin-Like Growth Factor II; Kinetics; Lysosomes; Mice; Muscle, Skeletal; Mutant Chimeric Proteins; Myoblasts; Plasmids; Receptor, IGF Type 2; Transfection

The experimental model of seizures which depends upon methionine sulfoximine (MSO) simulates the most striking form of human epilepsy. MSO generates epileptiform seizures in a large variety of animals, increases brain glycogen content and induces brain monoamines modifications. We selected two inbred lines of mice based upon their latency toward MSO-dependent seizures, named as MSO-Fast (sensitive), having short latency toward MSO, and MSO-Slow (resistant) with a long latency. We determined 13 monoamines and glycogen contents in brain cortices of the MSO-Fast and slow lines in order to determine the relationships with MSO-dependent seizures. The present data show that using these MSO-Fast and MSO-Slow inbred lines it could be demonstrated that: (1) in basal conditions the neurotransmitter 5-HT is significantly higher in MSO-Fast mice than in MSO-Slow ones; (2) MSO in both lines induced a significant increase in brain content of DOPAC (3,4-dihydroxyphenylacetic acid), HVA (homovanillic acid), MHPG (3-methoxy-4-hydroxyphenylglycol), and 5-HT (serotonin); a significant decrease in MSO-Slow mice in brain content of NME (normetepinephrine), and 5-HIAA (5-hydroxyindoleacetic acid) and the variation of other monoamines were not significant; (3) the brain glycogen content is significantly higher in MSO-Fast mice than in MSO-Slow ones, both in basal conditions and after MSO administration. From our data, we propose that brain glycogen content may constitute a defense against epileptic attack, as glycogen may be degraded down to glucose-6-phosphate that can be used to either postpone the epileptic attack or to provide neurons with energy when they needed it. Brain glycogen might therefore be considered as a molecule that can contribute to struggle seizures, at least in MSO-dependent seizure. The 5-HT content may constitute a defense against MSO-dependent epilepsy.

Topics: 3,4-Dihydroxyphenylacetic Acid; Animals; Biogenic Monoamines; Brain; Disease Models, Animal; Glycogen; Hydroxyindoleacetic Acid; Methionine Sulfoximine; Mice; Mice, Inbred Strains; Seizures; Serotonin; Thiophenes

The present investigation aimed to study the protective effect of intermittent normothermic cardioplegia in rabbit's hypertrophic hearts.. The parameters chosen were 1) the ratio heart weight / body weight, 2) the myocardial glycogen levels, 3) ultrastructural changes of light and electron microscopy, and 4) mitochondrial respiration.. 1) The experimental model, coarctation of the aorta induced left ventricular hypertrophy; 2) the temporal evolution of the glycogen levels in hypertrophic myocardium demonstrates that there is a significant decrease; 3) It was observed a time-dependent trend of higher oxygen consumption values in the hypertrophic group; 4) there was a significant time-dependent decrease in the respiratory coefficient rate in the hypertrophic group; 5) the stoichiometries values of the ADP: O2 revealed the downward trend of the values of the hypertrophic group; 6) It was possible to observe damaged mitochondria from hypertrophic myocardium emphasizing the large heterogeneity of data.. The acquisition of biochemical data, especially the increase in speed of glycogen breakdown, when anatomical changes are not detected, represents an important result even when considering all the difficulties inherent in the process of translating experimental results into clinical practice. With regard to the adopted methods, it is clear that morphometric methods are less specific. Otherwise, the biochemical data allow detecting alterations of glycogen concentrations and mitochondria respiration before the morphometric alterations should be detected.

Topics: Animals; Body Weight; Cardiomyopathy, Hypertrophic; Disease Models, Animal; Glycogen; Heart; Heart Arrest, Induced; Mitochondria, Heart; Myocardial Reperfusion Injury; Myocardium; Organ Size; Oxygen Consumption; Rabbits; Random Allocation; Statistics, Nonparametric

Diabetes mellitus is one of the three most common modem diseases. A number of animal models is used in investigations of the mechanisms of development of the disease. Most of these models replicate the symptoms of type 1 diabetes mellitus. The development of type 2 diabetes is caused by the insulin resistance, hyperglycemia, structural and functional disorders of the pancreatic cells. Investigation of pathogenesis of type 2 diabetes is complicated by the lack of adequate models of this disease. In this work, based on existing hyperglycemia model, we propose the model of metabolic syndrome as a precursor of type 2 diabetes. The development of metabolic syndrome symptoms was caused by 28 days long intramuscular injection of protamine sulfate to guinea pigs at a dose of 15 mg/kg along with keeping of animals on a high glucose diet. Increased blood glucose and cholesterol levels, reduction of glycogen in liver, the structural and functional damage and reduce in the number of functionally active beta-cells in the pancreas of the experimental animals were observed. The results confirm the development of the metabolic syndrome symptoms in experimental animals, which makes it possible to use such methodical approach in creation of promising type 2 diabetes model.

Topics: Animals; Diabetes Mellitus, Type 2; Diet; Disease Models, Animal; Glucose; Glycogen; Guinea Pigs; Hyperglycemia; Injections, Intramuscular; Insulin Resistance; Insulin-Secreting Cells; Liver; Male; Metabolic Syndrome; Protamines

In traditional medicine, Kai Xin San (KXS), composed of ginseng (Panax ginseng), hoelen (Wolfiporia cocos), polygala (Polygala tenuifolia) and Acorus gramineus, is famous for the treatment of emotion-thought disease, such as settling fright, quieting the spirit and nourishing the heart.. The present study investigated the effect of KXS on chronic fatigue syndrome (CFS) mice induced by forced wheel running.. Seventy two healthy adult male Kunming mice were randomly divided into six groups: home cage control group, CFS group, CFS group with Modafinil treatment at 13 mg/kg/d doge, KXS treatment at 175 mg/kg/d, 350 mg/kg/d and 700 mg/kg/d doge. CFS mice were induced by forced wheel running with higher speed for 4 weeks and then taken an exhausted exercise. The biochemical parameters including serum lactate dehydrogenase (LDH), serum urea nitrogen (SUN), serum testosterone (T), liver glycogen (LG), muscle glycogen (MG) and muscle lactic acid (MLA) were determined by using commercially available kits. The splenocytes proliferation from mice was examined by MTT method. The levels of interleukin-2 (IL-2) and interleukin-4 (IL-4) secreted by splenocytes were determined by ELISA.. CFS mice with KXS administration exhibited less electric shock time when compared with CFS group without drug treatment. The effect of KXS has after demonstrated reduction in SUN, LDH and MLA levels and an increase in T, LG and MG levels. CFS mice with KXS could improve the proliferation of splenocytes compared with CFS group without drug treatment. The cultured splenocytes from CFS mice without KXS supplementation produced more interleukin-2 (IL-2) but less interleukin-4 (IL-4) when compared with home cage control mice. The cultured splenocytes of CFS mice with KXS supplementation produced more interleukin-2 (IL-2) but less interleukin-4 (IL-4) when compared with CFS group without drug treatment.. The results of this preliminary study provide evidence that KXS could ameliorate CFS by affecting the physiological markers for fatigue. This study also supported the use of KXS against CFS by improving the proliferation of splenocytes from CFS mice and modulating the disturbance of cytokines induced by CFS.

Topics: Animals; Blood Urea Nitrogen; Cell Proliferation; Disease Models, Animal; Drugs, Chinese Herbal; Fatigue Syndrome, Chronic; Glycogen; Interleukin-2; Interleukin-4; L-Lactate Dehydrogenase; Lactic Acid; Magnoliopsida; Male; Mice; Physical Exertion; Spleen; Testosterone

Glycogen storage in the α-glucosidase knockout((6neo/6neo)) mouse recapitulates the biochemical defect that occurs in the human condition; as such, this mouse serves as a model for the inherited metabolic deficiency of lysosomal acid α-glucosidase known as Pompe disease. Although this model has been widely used for the assessment of therapies, the time course of glycogen accumulation that occurs as untreated Pompe mice age has not been reported. To address this, we developed a quantitative method involving amyloglucosidase digestion of glycogen and quantification of the resulting free glucose by liquid chromatography/electrospray ionization-tandem mass spectrometry. The method was sensitive enough to measure as little as 0.1 μg of glycogen in tissue extracts with intra- and interassay coefficients of variation of less than 12%. Quantification of glycogen in tissues from Pompe mice from birth to 26 weeks of age showed that, in addition to the accumulation of glycogen in the heart and skeletal muscle, glycogen also progressively accumulated in the brain, diaphragm, and skin. Glycogen storage was also evident at birth in these tissues. This method may be particularly useful for longitudinal assessment of glycogen reduction in response to experimental therapies being trialed in this model.

Topics: alpha-Glucosidases; Animals; Chromatography, Liquid; Disease Models, Animal; Glycogen; Glycogen Storage Disease Type II; Mice; Mice, Knockout; Muscle, Skeletal; Spectrometry, Mass, Electrospray Ionization

Dynamin 2 (Dnm2) is involved in endocytosis and intracellular membrane trafficking through its function in vesicle formation from distinct membrane compartments. Heterozygous (HTZ) mutations in the DNM2 gene cause dominant centronuclear myopathy or Charcot-Marie-Tooth neuropathy. We generated a knock-in Dnm2R465W mouse model expressing the most frequent human mutation and recently reported that HTZ mice progressively developed a myopathy. We investigated here the cause of neonatal lethality occurring in homozygous (HMZ) mice. We show that HMZ mice present at birth with a reduced body weight, hypoglycemia, increased liver glycogen content and hepatomegaly, in agreement with a defect in neonatal autophagy. In vitro studies performed in HMZ embryonic fibroblasts point out to a decrease in the autophagy flux prior to degradation at the autolysosome. We show that starved HMZ cells have a higher number of immature autophagy-related structures probably due to a defect of acidification. Our results highlight the role of Dnm2 in the cross talk between endosomal and autophagic pathways and evidence a new role of Dnm2-dependent membrane trafficking in autophagy which may be relevant in DNM2-related human diseases.

Topics: Animals; Autophagy; Disease Models, Animal; Dynamin II; Fibroblasts; Gene Expression Regulation; Genotype; Glycogen; Homozygote; Liver; Lysosomes; Mice; Mice, Inbred C57BL; Myopathies, Structural, Congenital; Subcellular Fractions; Time Factors

Under physiological conditions, most neurons keep glycogen synthase (GS) in an inactive form and do not show detectable levels of glycogen. Nevertheless, aberrant glycogen accumulation in neurons is a hallmark of patients suffering from Lafora disease or other polyglucosan disorders. Although these diseases are associated with mutations in genes involved in glycogen metabolism, the role of glycogen accumulation remains elusive. Here, we generated mouse and fly models expressing an active form of GS to force neuronal accumulation of glycogen. We present evidence that the progressive accumulation of glycogen in mouse and Drosophila neurons leads to neuronal loss, locomotion defects and reduced lifespan. Our results highlight glycogen accumulation in neurons as a direct cause of neurodegeneration.

Topics: Animals; Disease Models, Animal; Drosophila; Glycogen; Glycogen Storage Disease; Glycogen Synthase; Locomotion; Longevity; Mice; Neurodegenerative Diseases; Neurons

We previously demonstrated that hexokinase (HK) II plays a key role in the pathophysiology of ischemia-reperfusion (I/R) injury of the heart (Smeele et al. Circ Res 108: 1165-1169, 2011; Wu et al. Circ Res 108: 60-69, 2011). However, it is unknown whether HKII also plays a key role in I/R injury and healing thereafter in skeletal muscle, and if so, through which mechanisms. We used male wild-type (WT) and heterozygous HKII knockout mice (HKII(+/-)) and performed in vivo unilateral skeletal muscle I/R, executed by 90 min hindlimb occlusion using orthodontic rubber bands followed by 1 h, 1 day, or 14 days reperfusion. The contralateral (CON) limb was used as internal control. No difference was observed in muscle glycogen turnover between genotypes at 1 h reperfusion. At 1 day reperfusion, the model resulted in 36% initial cell necrosis in WT gastrocnemius medialis (GM) muscle that was doubled (76% cell necrosis) in the HKII(+/-) mice. I/R-induced apoptosis (29%) was similar between genotypes. HKII reduction eliminated I/R-induced mitochondrial Bax translocation and oxidative stress at 1 day reperfusion. At 14 days recovery, the tetanic force deficit of the reperfused GM (relative to control GM) was 35% for WT, which was doubled (70%) in HKII(+/-) mice, mirroring the initial damage observed for these muscles. I/R increased muscle fatigue resistance equally in GM of both genotypes. The number of regenerating fibers in WT muscle (17%) was also approximately doubled in HKII(+/-) I/R muscle (44%), thus again mirroring the increased cell death in HKII(+/-) mice at day 1 and suggesting that HKII does not significantly affect muscle regeneration capacity. Reduced HKII was also associated with doubling of I/R-induced fibrosis. In conclusion, reduced muscle HKII protein content results in impaired muscle functionality during recovery from I/R. The impaired recovery seems to be mainly a result of a greater susceptibility of HKII(+/-) mice to the initial I/R-induced necrosis (not apoptosis), and not a HKII-related deficiency in muscle regeneration.

Topics: Animals; Apoptosis; bcl-2-Associated X Protein; Disease Models, Animal; Down-Regulation; Fibrosis; Glycogen; Hexokinase; Hindlimb; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Microcirculation; Mitochondria, Muscle; Muscle Fatigue; Muscle Strength; Muscle, Skeletal; Necrosis; Neovascularization, Physiologic; Oxidative Stress; Recovery of Function; Regeneration; Regional Blood Flow; Reperfusion Injury; Time Factors

McArdle disease (glycogenosis type V), the most common muscle glycogenosis, is a recessive disorder caused by mutations in PYGM, the gene encoding myophosphorylase. Patients with McArdle disease typically experience exercise intolerance manifested as acute crises of early fatigue and contractures, sometimes with rhabdomyolysis and myoblobinuria, triggered by static muscle contractions or dynamic exercises. Currently, there are no therapies to restore myophosphorylase activity in patients. Although two spontaneous animal models for McArdle disease have been identified (cattle and sheep), they have rendered a limited amount of information on the pathophysiology of the disorder; therefore, there have been few opportunities for experimental research in the field. We have developed a knock-in mouse model by replacing the wild-type allele of Pygm with a modified allele carrying the common human mutation, p.R50X, which is the most frequent cause of McArdle disease. Histochemical, biochemical and molecular analyses of the phenotype, as well as exercise tests, were carried out in homozygotes, carriers and wild-type mice. p.R50X/p.R50X mice showed undetectable myophosphorylase protein and activity in skeletal muscle. Histochemical and biochemical analyses revealed massive muscle glycogen accumulation in homozygotes, in contrast to heterozygotes or wild-type mice, which did not show glycogen accumulation in this tissue. Additional characterization confirmed a McArdle disease-like phenotype in p.R50X/p.R50X mice, i.e. they had hyperCKaemia and very poor exercise performance, as assessed in the wire grip and treadmill tests (6% and 5% of the wild-type values, respectively). This model represents a powerful tool for in-depth studies of the pathophysiology of McArdle disease and other neuromuscular disorders, and for exploring new therapeutic approaches for genetic disorders caused by premature stop codon mutations.

Topics: Alleles; Animals; Creatine Kinase; Disease Models, Animal; Female; Gene Knock-In Techniques; Glycogen; Glycogen Phosphorylase, Muscle Form; Glycogen Storage Disease Type V; Heterozygote; Homozygote; Male; Mice; Muscle, Skeletal; Myoglobin; Myoglobinuria; Physical Conditioning, Animal

Glycogen storage disease type IIIa (GSD IIIa) is an autosomal recessive disease caused by deficiency of glycogen debranching enzyme (GDE) in liver and muscle. The disorder is clinically heterogeneous and progressive, and there is no effective treatment. Previously, a naturally occurring dog model for this condition was identified in curly-coated retrievers (CCR). The affected dogs carry a frame-shift mutation in the GDE gene and have no detectable GDE activity in liver and muscle. We characterized in detail the disease expression and progression in eight dogs from age 2 to 16 months. Monthly blood biochemistry revealed elevated and gradually increasing serum alanine transaminase (ALT), aspartate transaminase (AST) and alkaline phosphatase (ALP) activities; serum creatine phosphokinase (CPK) activity exceeded normal range after 12 months. Analysis of tissue biopsy specimens at 4, 12 and 16 months revealed abnormally high glycogen contents in liver and muscle of all dogs. Fasting liver glycogen content increased from 4 months to 12 months, but dropped at 16 months possibly caused by extended fibrosis; muscle glycogen content continually increased with age. Light microscopy revealed significant glycogen accumulation in hepatocytes at all ages. Liver histology showed progressive, age-related fibrosis. In muscle, scattered cytoplasmic glycogen deposits were present in most cells at 4 months, but large, lake-like accumulation developed by 12 and 16 months. Disruption of the contractile apparatus and fraying of myofibrils was observed in muscle at 12 and 16 months by electron microscopy. In conclusion, the CCR dogs are an accurate model of GSD IIIa that will improve our understanding of the disease progression and allow opportunities to investigate treatment interventions.

Topics: Adipocytes; Animals; Disease Models, Animal; Dog Diseases; Dogs; Fasting; Glycogen; Glycogen Storage Disease Type III; Hepatocytes; Lipids; Liver; Liver Cirrhosis; Muscles

American ginseng (Panax quinquefolius L.) root health benefits include treatment of type 2 diabetes and this study evaluated the hypoglycemic effects of American red ginseng (ARG). ARG roots have increased bioactive phenolic contents, such as cinnamic acid and ferulic acid during the steaming process. The antihyperglycemic effects of methanol fraction extract of ARG, ferulic acid, and cinnamic acid were examined using a type 2 diabetic mouse model. The ARG treated group presented relatively lower blood glucose levels than the control group (P < 0.05). In addition, the glycogen and high density lipoprotein (HDL) contents were significantly increased while levels of plasma cholesterol and low density lipoprotein (LDL) concentration were significantly decreased in the ARG treated group. The groups treated with ferulic and cinnamic acids showed similar effects as those found in the ARG treated group. Thus, it is suggested that ARG roots, ferulic acid, and cinnamic acid have hypoglycemic effects in an animal model.. This study was conducted to elucidate the hypoglycemic effects of American red ginseng (ARG) using a type 2 diabetic mouse model. ARG showed an enhanced antioxidant capacity and higher antihyperglycemia effect. The glycogen and high density lipoprotein (HDL) contents were significantly increased while levels of plasma cholesterol and low density lipoprotein (LDL) concentration were significantly decreased in the ARG treated group. It is suggested that ARG has a potential to be used for human diabetic treatment.

Topics: Animals; Blood Glucose; Cinnamates; Coumaric Acids; Diabetes Mellitus, Type 2; Disease Models, Animal; Glutathione Peroxidase; Glycogen; Hypoglycemic Agents; Insulin; Lipid Peroxidation; Lipoproteins, HDL; Lipoproteins, LDL; Male; Malondialdehyde; Mice; Mice, Inbred Strains; Panax; Phytotherapy; Plant Extracts; Plant Roots; Superoxide Dismutase

Pompe disease is an inherited lysosomal storage disease that results from a deficiency in the enzyme acid α-glucosidase (GAA), and is characterized by progressive accumulation of lysosomal glycogen primarily in heart and skeletal muscles. Recombinant human GAA (rhGAA) is the only approved enzyme replacement therapy (ERT) available for the treatment of Pompe disease. Although rhGAA has been shown to slow disease progression and improve some of the pathophysiogical manifestations, the infused enzyme tends to be unstable at neutral pH and body temperature, shows low uptake into some key target tissues, and may elicit immune responses that adversely affect tolerability and efficacy. We hypothesized that co-administration of the orally-available, small molecule pharmacological chaperone AT2220 (1-deoxynojirimycin hydrochloride, duvoglustat hydrochloride) may improve the pharmacological properties of rhGAA via binding and stabilization. AT2220 co-incubation prevented rhGAA denaturation and loss of activity in vitro at neutral pH and 37°C in both buffer and blood. In addition, oral pre-administration of AT2220 to rats led to a greater than two-fold increase in the circulating half-life of intravenous rhGAA. Importantly, co-administration of AT2220 and rhGAA to GAA knock-out (KO) mice resulted in significantly greater rhGAA levels in plasma, and greater uptake and glycogen reduction in heart and skeletal muscles, compared to administration of rhGAA alone. Collectively, these preclinical data highlight the potentially beneficial effects of AT2220 on rhGAA in vitro and in vivo. As such, a Phase 2 clinical study has been initiated to investigate the effects of co-administered AT2220 on rhGAA in Pompe patients.

Topics: 1-Deoxynojirimycin; alpha-Glucosidases; Animals; Buffers; Disease Models, Animal; Enzyme Activation; Enzyme Stability; Glycogen; Glycogen Storage Disease Type II; Half-Life; Humans; Mice; Mice, Knockout; Protein Denaturation; Rats; Recombinant Proteins

Increasing energy storage capacity by elevating creatine and phosphocreatine (PCr) levels to increase ATP availability is an attractive concept for protecting against ischaemia and heart failure. However, testing this hypothesis has not been possible since oral creatine supplementation is ineffectual at elevating myocardial creatine levels. We therefore used mice overexpressing creatine transporter in the heart (CrT-OE) to test for the first time whether elevated creatine is beneficial in clinically relevant disease models of heart failure and ischaemia/reperfusion (I/R) injury.. CrT-OE mice were selected for left ventricular (LV) creatine 20-100% above wild-type values and subjected to acute and chronic coronary artery ligation. Increasing myocardial creatine up to 100% was not detrimental even in ageing CrT-OE. In chronic heart failure, creatine elevation was neither beneficial nor detrimental, with no effect on survival, LV remodelling or dysfunction. However, CrT-OE hearts were protected against I/R injury in vivo in a dose-dependent manner (average 27% less myocardial necrosis) and exhibited greatly improved functional recovery following ex vivo I/R (59% of baseline vs. 29%). Mechanisms contributing to ischaemic protection in CrT-OE hearts include elevated PCr and glycogen levels and improved energy reserve. Furthermore, creatine loading in HL-1 cells did not alter antioxidant defences, but delayed mitochondrial permeability transition pore opening in response to oxidative stress, suggesting an additional mechanism to prevent reperfusion injury.. Elevation of myocardial creatine by 20-100% reduced myocardial stunning and I/R injury via pleiotropic mechanisms, suggesting CrT activation as a novel, potentially translatable target for cardiac protection from ischaemia.

Topics: Animals; Cell Line; Creatine; Disease Models, Animal; Energy Metabolism; Glycogen; Heart Failure; Magnetic Resonance Imaging, Cine; Membrane Transport Proteins; Mice; Mice, Inbred C57BL; Mice, Transgenic; Mitochondria, Heart; Mitochondrial Membrane Transport Proteins; Mitochondrial Permeability Transition Pore; Myocardial Infarction; Myocardial Reperfusion Injury; Myocardial Stunning; Myocardium; Necrosis; Oxidative Stress; Phosphocreatine; Time Factors; Up-Regulation; Ventricular Function, Left; Ventricular Remodeling

The objective of this study was to evaluate fetal weight, histomorphometric changes and proliferative activity, apoptosis and angiogenesis of the placenta in rats with hypothyroidism. Thirty-six adult female rats were divided into two groups with 18 animals each: control and hypothyroidism. Hypothyroidism was induced by daily administration of propylthiouracil (1 mg/animal). The administration began five days before becoming pregnant and the animals were sacrificed at 14 or 19 days of gestation. The control group received a placebo. The number and weight of fetuses and the rate of fetal death was determined, as well as the morphometric characteristics, the immunohistochemical expression of cell division control protein 47 (CDC)-47 and vascular endothelial growth factor (VEGF) and the number of apoptotic cells in the placental disk. The data were analysed by Mann-Whitney U test. Hypothyroidism reduced the weight of fetuses and of the uterus and placenta (P<0.05), altered the thickness of the placental labyrinth and spongiotrophoblast (P<0.05), increased the population of glycogen cells in the spongiotrophoblast (P<0.05), interfered with the vascular development of the placental labyrinth and decreased VEGF expression (P<0.05), reduced the expression of CDC-47 and cellularity and increased the apoptotic rate in the placental disk (P<0.05). We conclude that hypothyroidism affects fetal weight by altering the proliferative activity, apoptosis and vascularisation of the placenta.

Topics: Adenosine Triphosphatases; Animals; Apoptosis; Biomarkers; Cell Proliferation; Disease Models, Animal; DNA-Binding Proteins; Down-Regulation; Female; Fetal Death; Fetal Growth Retardation; Fetal Weight; Gestational Age; Glycogen; Hypothyroidism; Immunohistochemistry; Minichromosome Maintenance Complex Component 7; Neovascularization, Physiologic; Placenta; Pregnancy; Propylthiouracil; Rats; Trophoblasts; Vascular Endothelial Growth Factor A

Glycogenotic hepatocellular carcinoma (HCC) with glycogen-ground-glass hepatocytes has recently been described as an allegedly "novel variant" of HCC, but neither the historical background nor the heuristic relevance of this observation were put in perspective. In the present contribution, the most important findings in animal models and human beings related to the emergence and further evolution of excessively glycogen storing (glycogenotic) hepatocytes with and without ground glass features during neoplastic development have been summarized. Glycogenotic HCCs with glycogen-ground-glass hepatocytes represent highly differentiated neoplasms which contain subpopulations of cells phenotypically resembling those of certain types of preneoplastic hepatic foci and benign hepatocellular neoplasms. It is questionable whether the occurrence of glycogen-ground-glass hepatocytes in a glycogenotic HCC justifies its classification as a specific entity. The typical appearance of ground-glass hepatocytes is due to a hypertrophy of the smooth endoplasmic reticulum, which is usually associated with an excessive storage of glycogen and frequently also with an expression of the hepatitis B surface antigen. Sequential studies in animal models and observations in humans indicate that glycogen-ground-glass hepatocytes are a facultative, integral part of a characteristic cellular sequence commencing with focal hepatic glycogenosis potentially progressing to benign and malignant neoplasms. During this process highly differentiated glycogenotic cells including ground-glass hepatocytes are gradually transformed via various intermediate stages into poorly differentiated glycogen-poor, basophilic (ribosome-rich) cancer cells. Histochemical, microbiochemical, and molecular biochemical studies on focal hepatic glycogenosis and advanced preneoplastic and neoplastic lesions in tissue sections and laser-dissected specimens in rat and mouse models have provided compelling evidence for an early insulinomimetic effect of oncogenic agents, which is followed by a fundamental metabolic switch from gluconeogenesis towards the pentose-phosphate pathway and the Warburg type of glycolysis during progression from preneoplastic hepatic glycogenosis to the highly proliferative malignant phenotype.

Topics: Animals; Carcinoma, Hepatocellular; Cell Differentiation; Cell Shape; Disease Models, Animal; Disease Progression; Endoplasmic Reticulum; Glycogen; Glycogen Storage Disease; Hepatocytes; Humans; Liver Neoplasms; Mice; Phenotype; Precancerous Conditions; Rats

Therapies for certain voice disorders purport principles of skeletal muscle rehabilitation to increase muscle mass, strength, and endurance. However, applicability of limb muscle rehabilitation to the laryngeal muscles has not been tested. In this study, the authors examined the feasibility of the rat thyroarytenoid muscle to remodel as a consequence of increased activity instantiated through chronic electrical stimulation.. Twenty adult Sprague-Dawley rats (Rattus norvegicus), assigned to a 1-week or 2-week stimulation group, were implanted with a nerve cuff electrode placed around the right recurrent laryngeal nerve and were fitted with a head connector. All animals were placed under anesthesia twice a day for 1 hr each time. Following the training, rats were killed, and thyroarytenoid muscles were isolated for histology and immunohistochemistry.. Mean muscle fiber area decreased, neuromuscular junction density increased, mitochondrial content increased qualitatively, and glycogen-positive fibers increased, demonstrating exercise-induced changes similar to those seen in limb muscles after endurance training.. Rat thyroarytenoid muscles are capable of remodeling in response to chronic electrical stimulation.

Topics: Animals; Chronic Disease; Disease Models, Animal; Electric Stimulation; Glycogen; Laryngeal Muscles; Male; Mitochondria; Muscle Fibers, Skeletal; Neuromuscular Junction; Physical Endurance; Rats; Rats, Sprague-Dawley; Voice Disorders

Advanced HF (heart failure) is associated with altered substrate metabolism. Whether modification of substrate use improves the course of HF remains unknown. The antihyperglycaemic drug MET (metformin) affects substrate metabolism, and its use might be associated with improved outcome in diabetic HF. The aim of the present study was to examine whether MET would improve cardiac function and survival also in non-diabetic HF. Volume-overload HF was induced in male Wistar rats by creating ACF (aortocaval fistula). Animals were randomized to placebo/MET (300 mg·kg(-1) of body weight·day(-1), 0.5% in food) groups and underwent assessment of metabolism, cardiovascular and mitochondrial functions (n=6-12/group) in advanced HF stage (week 21). A separate cohort served for survival analysis (n=10-90/group). The ACF group had marked cardiac hypertrophy, increased LVEDP (left ventricular end-diastolic pressure) and lung weight confirming decompensated HF, increased circulating NEFAs (non-esterified 'free' fatty acids), intra-abdominal fat depletion, lower glycogen synthesis in the skeletal muscle (diaphragm), lower myocardial triacylglycerol (triglyceride) content and attenuated myocardial (14)C-glucose and (14)C-palmitate oxidation, but preserved mitochondrial respiratory function, glucose tolerance and insulin sensitivity. MET therapy normalized serum NEFAs, decreased myocardial glucose oxidation, increased myocardial palmitate oxidation, but it had no effect on myocardial gene expression, AMPK (AMP-activated protein kinase) signalling, ATP level, mitochondrial respiration, cardiac morphology, function and long-term survival, despite reaching therapeutic serum levels (2.2±0.7 μg/ml). In conclusion, MET-induced enhancement of myocardial fatty acid oxidation had a neutral effect on cardiac function and survival. Recently reported cardioprotective effects of MET may not be universal to all forms of HF and may require AMPK activation or ATP depletion. No increase in mortality on MET supports its safe use in diabetic HF.

Topics: AMP-Activated Protein Kinase Kinases; Animals; Blood Glucose; Body Weight; Disease Models, Animal; Drug Evaluation, Preclinical; Glycogen; Heart Failure; Hemodynamics; Hypoglycemic Agents; Lipid Metabolism; Lung; Male; Metformin; Mitochondria, Heart; Myocardium; Organ Size; Protein Kinases; Rats; Rats, Wistar; Survival Analysis; Ultrasonography

Enzyme replacement therapy (ERT) with acid α-glucosidase has become available for Pompe disease; however, the response of skeletal muscle, as opposed to the heart, has been attenuated. The poor response of skeletal muscle has been attributed to the low abundance of the cation-independent mannose-6-phosphate receptor (CI-MPR) in skeletal muscle compared to heart. To further understand the role of CI-MPR in Pompe disease, muscle-specific CI-MPR conditional knockout (KO) mice were crossed with GAA-KO (Pompe disease) mice. We evaluated the impact of CI-MPR-mediated uptake of GAA by evaluating ERT in CI-MPR-KO/GAA-KO (double KO) mice. The essential role of CI-MPR was emphasized by the lack of efficacy of ERT as demonstrated by markedly reduced biochemical correction of GAA deficiency and of glycogen accumulations in double KO mice, in comparison with the administration of the same therapeutic doses in GAA-KO mice. Clenbuterol, a selective β(2)-agonist, enhanced the CI-MPR expression in skeletal tissue and also increased efficacy from GAA therapy, thereby confirming the key role of CI-MPR with regard to enzyme replacement therapy in Pompe disease. Biochemical correction improved in both muscle and non-muscle tissues, indicating that therapy could be similarly enhanced in other lysosomal storage disorders. In summary, enhanced CI-MPR expression might improve the efficacy of enzyme replacement therapy in Pompe disease through enhancing receptor-mediated uptake of GAA.

Topics: Adrenergic beta-Agonists; alpha-Glucosidases; Animals; Clenbuterol; Disease Models, Animal; Enzyme Replacement Therapy; Glycogen; Glycogen Storage Disease Type II; Male; Mice; Mice, Knockout; Motor Activity; Muscle, Skeletal; Receptor, IGF Type 2

Potentilla alba L. (Rosaceae) rhizomes have anti-inflammatory, antioxidant, and adaptogenic effects and are used for the treatment of diarrhea and intestinal colic. However, the data concerning the adaptogenic and central nervous system activities of P. alba are fragmentary.. To determine the effect of oral administration of dried P. alba extract on the swimming endurance, light/dark exploration, and open-field tests for mice.. The mice were orally administered Rhodiola rosea extract (RR group); dry extract of P. alba at doses of 12, 36, or 72 mg/kg (groups: PA12, PA36, and PA72); or distilled water (control group) for 7 consecutive days.. The swimming times of the RR, PA36, and PA72 groups were significantly longer than those of the control group. The administration of P. alba significantly increased the light time, latency time, and the number of rearings in a dose-dependent manner. In the open-field test, the P. alba extract at a dose of 12 mg/kg produced a significant increase in the frequency of head dipping and the number of squares crossed and a significant decrease in grooming compared with the control treatment.. The current findings demonstrate that P. alba extracts significantly increased swimming endurance time and have anxiolytic-like action with a predominant locomotor component.

Topics: Adaptation, Psychological; Animals; Anti-Anxiety Agents; Behavior, Animal; Blood Glucose; Body Weight; Central Nervous System; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Administration Schedule; Drug Evaluation, Preclinical; Glycogen; Lactic Acid; Male; Mice; Mice, Inbred BALB C; Photoperiod; Phytotherapy; Plant Extracts; Potentilla; Rhizome; Rhodiola; Swimming

Changes in metabolic and myofilament phenotypes coincide in developing hearts. Posttranslational modification of sarcomere proteins influences contractility, affecting the energetic cost of contraction. However, metabolic adaptations to sarcomeric phenotypes are not well understood, particularly during pathophysiological stress. This study explored metabolic adaptations to expression of the fetal, slow skeletal muscle troponin I (ssTnI). Hearts expressing ssTnI exhibited no significant ATP loss during 5 min of global ischemia, while non-transgenic littermates (NTG) showed continual ATP loss. At 7 min ischemia TG-ssTnI hearts retained 80±12% of ATP versus 49±6% in NTG (P<0.05). Hearts expressing ssTnI also had increased AMPK phosphorylation. The mechanism of ATP preservation was augmented glycolysis. Glycolytic end products (lactate and alanine) were 38% higher in TG-ssTnI than NTG at 2 min and 27% higher at 5 min. This additional glycolysis was supported exclusively by exogenous glucose, and not glycogen. Thus, expression of a fetal myofilament protein in adult mouse hearts induced elevated anaerobic ATP production during ischemia via metabolic adaptations consistent with the resistance to hypoxia of fetal hearts. The general findings hold important relevance to both our current understanding of the association between metabolic and contractile phenotypes and the potential for invoking cardioprotective mechanisms against ischemic stress. This article is part of a Special Issue entitled "Possible Editorial".

Topics: Adenosine Triphosphate; AMP-Activated Protein Kinases; Animals; Disease Models, Animal; Gene Expression Regulation; Glycogen; Glycolysis; Male; Mice; Mice, Transgenic; Muscle Fibers, Slow-Twitch; Myocardial Ischemia; Myocardium; Phosphorylation; Troponin I

To evaluate the efficacy and safety of 2 analogs of L-carnitine on rats made insulin resistant by a high-fructose diet.. Using rats made insulin resistant by a high-fructose diet, we investigated the impact of 2 analogs of L-carnitine (25 mg/kg) and L-carnitine (250 mg/kg) on glucose, triglycerides and cholesterol blood levels, and liver glycogen. We also evaluated the safety of both analogs by the assessment of some biochemical and hematological parameters, a histological analysis and a study of embryotoxicity.. Both analogs reduced the levels of triglycerides in the liver and plasma, but only analog 2 reduced the cholesterol levels in insulin-resistant rats. No changes were observed in glycogen content. Safety evaluations revealed alterations in blood lymphocytes and embryotoxicity data.. This study demonstrated that the 2 analogs maintain the pharmacological properties of L-carnitine but have a different efficacy, potency and toxicity.

Topics: Animals; Blood Glucose; Body Weight; Carnitine; Chick Embryo; Cholesterol; Diet; Disease Models, Animal; Drug Evaluation, Preclinical; Embryo, Nonmammalian; Fructose; Glycogen; Insulin; Insulin Resistance; Liver; Male; Rats; Rats, Wistar; Sweetening Agents; Teratogens; Triglycerides; Vitamin B Complex

This study aimed to examine the effects of melatonin supplementation on liver glycogen levels in rats with streptozotocin- induced diabetes and subjected to acute swimming exercise.. Eighty Sprague-Dawley type adult male rats were divided into eight groups: Group 1, general control; Group 2, melatonin-supplemented control; Group 3, melatonin-supplemented diabetes; Group 4, swimming control; Group 5, melatonin-supplemented swimming; Group 6, melatonin-supplemented diabetic swimming; Group 7, diabetic swimming; Group 8, diabetic control. Melatonin was supplemented at a dose of 3 mg/kg/day intraperitoneally for four weeks. Liver tissue samples were collected and evaluated using a Nikon Eclipse E400 light microscope. All images obtained from the light microscope were transferred to PC medium and evaluated using Clemex PE 3.5 image analysis software.. The lowest liver glycogen levels in the study were found in group 4. Liver glycogen levels in groups 3, 6, 7 and 8 (the diabetic groups) were higher than group 4, but lower than those in groups 1 and 2. The lowest liver glycogen levels were obtained in groups 1 and 2.. The study indicates that melatonin supplementation maintains the liver glycogen levels that decrease in acute swimming exercise, while induced diabetes prevents this maintenance effect in rats.

Topics: Animals; Antioxidants; Diabetes Mellitus, Experimental; Dietary Supplements; Disease Models, Animal; Glycogen; Liver; Male; Melatonin; Physical Conditioning, Animal; Rats; Rats, Sprague-Dawley; Swimming

Mutations in the imprinted CDKN1C gene are associated with the childhood developmental disorder Beckwith-Wiedemann syndrome (BWS). Multiple mouse models with deficiency of Cdkn1c recapitulate some aspects of BWS but do not exhibit overgrowth of the newborn, a cardinal feature of patients with BWS. In this study, we found that Cdkn1c mutants attained a 20% increase in weight during gestation but experienced a rapid reversal of this positive growth trajectory very late in gestation. We observed a marked effect on placental development concurrently with this loss of growth potential, with the appearance of large thrombotic lesions in the labyrinth zone. The trilaminar trophoblast layer that separates the maternal blood sinusoids from fetal capillaries was disordered with a loss of sinusoidal giant cells, suggesting a role for Cdkn1c in maintaining the integrity of the maternal-fetal interface. Furthermore, the overgrowth of mutant pups decreased in the face of increasing intrauterine competition, identifying a role for Cdkn1c in the allocation of the maternal resources via the placenta. This work explains one difficulty in precisely replicating BWS in this animal model: the differences in reproductive strategies between the multiparous mouse, in which intrauterine competition is high, and humans, in which singleton pregnancies are more common.

Topics: Alleles; Animals; Animals, Newborn; Beckwith-Wiedemann Syndrome; Capillaries; Cyclin-Dependent Kinase Inhibitor p57; Disease Models, Animal; Embryo, Mammalian; Female; Fetus; Glycogen; Litter Size; Mice; Mice, 129 Strain; Mutation; Phenotype; Survival Analysis; Trophoblasts

Insulin replacement is the only effective therapy to manage hyperglycemia in type 1 diabetes mellitus (T1DM). Nevertheless, intensive insulin therapy has inadvertently led to insulin resistance. This study investigates mechanisms involved in the insulin resistance induced by hyperinsulinization. Wistar rats were rendered diabetic by alloxan injection, and 2 weeks later received saline or different doses of neutral protamine Hagedorn insulin (1.5, 3, 6, and 9 U/day) over 7 days. Insulinopenic-untreated rats and 6U- and 9U-treated rats developed insulin resistance, whereas 3U-treated rats revealed the highest grade of insulin sensitivity, but did not achieve good glycemic control as 6U- and 9U-treated rats did. This insulin sensitivity profile was in agreement with glucose transporter 4 expression and translocation in skeletal muscle, and insulin signaling, phosphoenolpyruvate carboxykinase/glucose-6-phosphatase expression and glycogen storage in the liver. Under the expectation that insulin resistance develops in hyperinsulinized diabetic patients, we believe insulin sensitizer approaches should be considered in treating T1DM.

Topics: Alloxan; Animals; Diabetes Mellitus, Experimental; Disease Models, Animal; Dose-Response Relationship, Drug; Forkhead Transcription Factors; Glucose; Glucose Transporter Type 4; Glucose-6-Phosphatase; Glycogen; Hypoglycemic Agents; Insulin; Insulin Resistance; Liver; Male; Muscle, Skeletal; Nerve Tissue Proteins; Protein Serine-Threonine Kinases; Rats; Rats, Wistar

The purpose of this study was to investigate the potential acute and 28-day repeated oral toxicities of besifloxacin (BAF) in Wistar albino rats. In oral acute and repeated dose study, BAF was administered to both sex of rats, at dose levels of 0, 300, 600, 900 mg/kg/day and 0, 100, 200, 500 mg/kg/day, respectively. In the acute study, total white blood cell (WBC) (male, 43.74%; female, 42.60%) and total bilirubin (T-BIL) (male, 80%; female, 60%) were significantly increase, total protein (TP) (male, 23.24%; 27.80%) was significantly decreased, and significant incidence of pericholangitis (male, 83.33%; female, 75%) was shown in males and females of high-dose groups. In repeated oral dose toxicity study, similar type effects were also observed after serum hematological and serum biochemical analysis, whereas additionally sever hepatic injury and focal ulceration in gastric mucosa also observed in high dose groups of both sexes after histopathological analysis. However these toxic effects of besifloxacin were transient and reversible and no-observed adverse effect level (NOAEL) were 300 mg/kg/day for acute and 100 mg/kg/day for repeated dose toxicity study, respectively.

Topics: Achilles Tendon; Animals; Anti-Bacterial Agents; Azepines; Bilirubin; Blood Platelets; Chemical and Drug Induced Liver Injury; Disease Models, Animal; Female; Fluoroquinolones; Glycogen; Joints; Leukocyte Count; Liver; Male; Photosensitivity Disorders; Rats; Rats, Wistar; Stomach Ulcer; Thrombocytosis; Toxicity Tests, Acute; Toxicity Tests, Subacute

Hepatocytes are an important research tool used for numerous applications. However, a short life span and a limited capacity to replicate in vitro limit the usefulness of primary hepatocyte cultures. We have hypothesized that in vivo priming of hepatocyte could make them more susceptible to growth factors in the medium for continuous proliferation in vitro. Here, a novel approach used to establish hepatocyte cell lines that included hepatocyte priming in vivo prior to culture with a 3,5-diethoxycarbonyl-1,4-dihydrocollidine diet was attempted. The cell line grew in a monolayer while maintaining a granular cytoplasm and a round nucleus. Electron microscopy displayed hepatocyte-like features including mitochondria, glycogen granules, and the presence of bile canaliculi. This cell line expressed many mature hepatocyte-specific genes including albumin, alpha1-antitrypsin, glucose 6-phosphatase, and tyrosine aminotransferase. Functional characteristic of hepatocytes like the ability to store glycogen, lipid, and synthesis of urea is well demonstrated by this cell line. These cells demonstrated anchorage dependent growth properties in soft agar and did not form tumors after transplantation into nude mice. This cell line can be sustained in culture for more than 100 passages (>1.5 years) without undergoing noticeable morphological changes or transformation. This novel method resulted in the establishment of an immortal, non-transformed hepatocyte cell line with functional characteristics that may aid research of cell metabolism, toxicology, and hepatocyte transplantation.

Topics: Albumins; Animals; Cell Line; Chemical and Drug Induced Liver Injury; Disease Models, Animal; Glucose-6-Phosphatase; Glycogen; Hepatocytes; Lipids; Liver; Male; Mice; Pyridines; Urea

Rubratoxin B is a mycotoxin that causes hypoglycemia and fatty liver. We investigated the effect of rubratoxin B on hepatic glycogen content and regulation, because blood glucose levels are associated with hepatic glycogen storage. Mice were treated with 1.5mg/kg rubratoxin B for 24h. Stomachs of treated mice became extremely swollen, and the contents were significantly heavier than those of controls. Hypoglycemia stimulates appetite; therefore, rubratoxin B may perturb satiation. Rubratoxin B evidently depleted hepatic glycogen stores. Phosphoenolpyruvate carboxykinase (PEPCK) activity and mRNA levels in treated mice were reduced, indicating that rubratoxin B caused hepatic glycogen depletion by inhibiting PEPCK. PEPCK activity and mRNA levels were reduced to similar degrees; it appears that PEPCK activity is regulated transcriptionally. Levels of the PEPCK gene trans-activators phospho-CREB (active form) and C/EBPα were significantly reduced in the livers of treated mice, suggesting that these factors are important for PEPCK gene transcription. Rubratoxicosis and fatty acid oxidation disorders (FAODs) share characteristic signs, such as robust appetite, hypoglycemia, hepatic glycogen depletion, and fatty liver. Although FAODs are generally considered genetic deficiencies, our results indicate that a chemical can also cause FAOD-like signs in mice.

Topics: Animals; Appetite Regulation; CCAAT-Enhancer-Binding Protein-alpha; Cyclic AMP Response Element-Binding Protein; Disease Models, Animal; Fatty Acids; Fatty Liver; Gastric Dilatation; Gene Expression Regulation, Enzymologic; Glycogen; Lipid Metabolism Disorders; Liver; Male; Mice; Mice, Inbred C3H; Mycotoxins; Oxidation-Reduction; Phosphoenolpyruvate Carboxykinase (GTP); Phosphorylation; Protein Processing, Post-Translational; RNA, Messenger; Specific Pathogen-Free Organisms

Glycogen storage disease type IV (GSD IV) is a rare autosomal recessive disorder caused by deficiency of the glycogen branching enzyme (GBE). The diagnostic feature of the disease is the accumulation of a poorly branched form of glycogen known as polyglucosan (PG). The disease is clinically heterogeneous, with variable tissue involvement and age of disease onset. Absence of enzyme activity is lethal in utero or in infancy affecting primarily muscle and liver. However, residual enzyme activity (5-20%) leads to juvenile or adult onset of a disorder that primarily affects muscle as well as central and peripheral nervous system. Here, we describe two mouse models of GSD IV that reflect this spectrum of disease. Homologous recombination was used to insert flippase recognition target recombination sites around exon 7 of the Gbe1 gene and a phosphoglycerate kinase-Neomycin cassette within intron 7, leading to a reduced synthesis of GBE. Mice bearing this mutation (Gbe1(neo/neo)) exhibit a phenotype similar to juvenile onset GSD IV, with wide spread accumulation of PG. Meanwhile, FLPe-mediated homozygous deletion of exon 7 completely eliminated GBE activity (Gbe1(-/-)), leading to a phenotype of lethal early onset GSD IV, with significant in utero accumulation of PG. Adult mice with residual GBE exhibit progressive neuromuscular dysfunction and die prematurely. Differently from muscle, PG in liver is a degradable source of glucose and readily depleted by fasting, emphasizing that there are structural and regulatory differences in glycogen metabolism among tissues. Both mouse models recapitulate typical histological and physiological features of two human variants of branching enzyme deficiency.

Topics: 1,4-alpha-Glucan Branching Enzyme; Animals; Disease Models, Animal; Glucans; Glycogen; Glycogen Storage Disease Type IV; Mice

Lafora disease (LD) is caused by mutations in either the laforin or malin gene. The hallmark of the disease is the accumulation of polyglucosan inclusions called Lafora Bodies (LBs). Malin knockout (KO) mice present polyglucosan accumulations in several brain areas, as do patients of LD. These structures are abundant in the cerebellum and hippocampus. Here, we report a large increase in glycogen synthase (GS) in these mice, in which the enzyme accumulates in LBs. Our study focused on the hippocampus where, under physiological conditions, astrocytes and parvalbumin-positive (PV(+)) interneurons expressed GS and malin. Although LBs have been described only in neurons, we found this polyglucosan accumulation in the astrocytes of the KO mice. They also had LBs in the soma and some processes of PV(+) interneurons. This phenomenon was accompanied by the progressive loss of these neuronal cells and, importantly, neurophysiological alterations potentially related to impairment of hippocampal function. Our results emphasize the relevance of the laforin-malin complex in the control of glycogen metabolism and highlight altered glycogen accumulation as a key contributor to neurodegeneration in LD.

Topics: Animals; Astrocytes; Disease Models, Animal; Female; Glycogen; Glycogen Synthase; Hippocampus; Humans; Inclusion Bodies; Lafora Disease; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Nerve Degeneration; Neurons

Rhodiola algida, Saussurea involucrata, and other herbs grown in Qinghai-Tibetan plateau have long been used to prevent and treat acute mountain sickness.. To screen and identify the anti-hypoxic constituents in the herbs grown in Qinghai-Tibetan plateau of Northwestern China.. The anti-hypoxic activities of 20 selected plateau herbs were examined against two positive controls, Rhodiola algida and acetazolamide, using the normobaric hypoxia model of mice. The herb with the highest activity was successively extracted with 70% ethanol, petroleum ether, chloroform, ethyl acetate and n-butanol. The extract with the highest activity was identified by comparing the survival time of mice under normobaric hypoxia condition after being subjected to different extracts. The identified extract was further tested by simulating high altitudes through an acute decompression model and a chronic decompression model for mice.. The herb found to have the highest anti-hypoxic activity was Saussurea involucrate (Kar. et Kir.) Sch.-Bip, and the most effective fraction was in the petroleum ether extract. Administration of petroleum ether extract of Saussurea involucrata (PESI) to mice at 50mg/kg significantly decreased the mortality of animals under acute decompression conditions. Changes in biochemical indicators for glycometabolism and energy metabolism, including adenosine triphosphate (ATP) content and adenosine triphosphatase (ATPase) activity in brain and cardiac muscle, lactic acid (LAC) and lactate dehydrogenase (LDH) in blood and cardiac muscles, blood sugar, and glycogen content in liver and skeletal muscle were reversed under chronic decompression conditions.. Saussurea involucrata (Kar. et Kir.) Sch.-Bip exhibits high anti-hypoxic activity that may be effective in preventing acute mountain sickness, and the active constituents are mainly in the petroleum ether extract.

Topics: Adenosine Triphosphate; Alkanes; Altitude Sickness; Animals; Blood Glucose; Brain; Ca(2+) Mg(2+)-ATPase; Decompression; Disease Models, Animal; Dose-Response Relationship, Drug; Energy Metabolism; Glycogen; Hypoxia; L-Lactate Dehydrogenase; Lactic Acid; Liver; Male; Mice; Mice, Inbred BALB C; Muscle, Skeletal; Myocardium; Plant Extracts; Plants, Medicinal; Saussurea; Sodium-Potassium-Exchanging ATPase; Solvents; Time Factors

To compare the effect of fluctuating glucose with sustained hyperglycaemia on systemic oxidative stress during 72 h of glucose infusion.. Catheterised male Sprague-Dawley rats were given either a continuous high (CHG), low (CLG) or pulsatile (FLU) infusion of glucose or saline (VEH) for 72 h. Plasma ascorbate oxidation ratio (AOR) and malondialdehyde (MDA) were used as biomarkers of oxidative stress and damage.. The FLU group showed significant increases in both plasma AOR and MDA at 48 and 72 h (p < 0.05 all cases), whereas the CHG group, despite being infused with three times the amount of glucose, only showed increased MDA levels at 72 h time point (p < 0.05).. Our data suggests that fluctuating glucose levels lead to oxidative stress similar to that of sustained hyperglycaemia despite a much lower total glycaemic exposure. Thus, our data supports the notion that fluctuating glucose may be relatively more deleterious than sustained hyperglycaemia.

Topics: Animals; Biomarkers; Blood Glucose; Disease Models, Animal; Glucose; Glycogen; Hyperglycemia; Infusions, Intravenous; Insulin; Liver; Male; Malondialdehyde; Oxidative Stress; Rats; Rats, Sprague-Dawley; Time Factors; Triglycerides

Phenylketonuria (PKU) is caused by deficiency of phenylalanine hydroxylase, leading to accumulation of phenylalanine and its metabolites. Clinical features of PKU patients include mental retardation, microcephaly, and seizures. Oxidative stress has been found in these patients, and is possibly related to neurophysiopatology of PKU. Regular exercise can leads to adaptation of antioxidant system, improving its capacity to detoxification reactive species. The aim of this study was to verify the effects of regular exercise on oxidative stress parameters in the brain of hyperphenylalaninemic rats. Animals were divided into sedentary (Sed) and exercise (Exe) groups, and subdivided into saline (SAL) and hyperphenylalaninemia (HPA). HPA groups were induced HPA through administration of alpha-methylphenylalanine and phenylalanine for 17 days, while SAL groups (n = 16-20) received saline. Exe groups conducted 2-week aerobic exercise for 20 min/day. At 18th day, animals were killed and the brain was homogenized to determine thiobarbituric acid reactives substances (TBA-RS) content, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities. Soleus muscles were collected to determine glycogen content as a marker of oxidative adaptation. Exe groups showed enhanced glycogen content. HPA condition caused an increase in TBA-RS and SOD, and reduces CAT and GPx. Exercise was able to prevent all changes seen in the HPA group, reaching control values, except for SOD activity. No changes were found in the ExeSAL group compared to SedSAL. Hyperphenylalaninemic rats were more responsive to the benefits provided by regular exercise. Physical training may be an interesting strategy to restore the antioxidant system in HPA.

Topics: Animals; Antioxidants; Brain Chemistry; Catalase; Disease Models, Animal; Glutathione Peroxidase; Glycogen; Muscle, Skeletal; Oxidative Stress; Phenylalanine; Phenylalanine Hydroxylase; Phenylketonurias; Physical Conditioning, Animal; Rats; Rats, Wistar; Superoxide Dismutase; Thiobarbituric Acid Reactive Substances

Transient administration of inhibitors of the renin-angiotensin system (RAS) during the prehypertensive period in rats and humans leads to a long-lasting lowering of blood pressure (BP). Our aim was to unravel the critical period in which activation of the RAS induces chronic effects on BP and to determine the role of renal function and structure in this process.. Studies were performed in Cyp1a1-Ren2 rats, which harbor a construct for the production of mouse renin. This construct becomes activated when indole-3-carbinol (I3C) is added to the diet. Young (4 weeks old) and adult (30 weeks old) Cyp1a1-Ren2 rats were randomly assigned to either the I3C treatment group or the control group. Renin production was stimulated from week 4 to 8 in young and week 30 to 34 in adult rats. BP follow-up was performed via photoelectric/oscillometric tail cuff method and intra-arterial BP was determined at 4, 8, 12 and 20 weeks of age or 34 and 38 weeks of age. Additionally, renal vascular resistance, albuminuria, renal inflammation and renal pathology were determined.. Up to 20 weeks of age, that is, 12 weeks after I3C withdrawal, mean arterial pressure (MAP) was significantly elevated in young I3C-treated rats (141 ± 7 mmHg) compared with controls (125 ± 6 mmHg). In adult rats, renin stimulation caused only a transient elevation in MAP, which returned to control values after I3C withdrawal. In young rats, the sustained pressor response was associated with increased indices of renal vascular resistance, glomerulosclerosis and tubulointerstitial damage as well as with a moderate inflammatory response. In adult rats, renal pathology and inflammation was significantly less than in young rats and was reversible.. Transient RAS stimulation causes sustained elevation in BP in young, but not in adult Cyp1a1-Ren2 transgenic rats and is associated with irreversible changes in renal structure and function and a moderate renal inflammatory response.

Topics: Age Factors; Animals; Arteries; Blood Pressure; Disease Models, Animal; Gene Expression; Glomerulosclerosis, Focal Segmental; Glycogen; Hypertension; Indoles; Kidney; Nephritis, Interstitial; Periodic Acid-Schiff Reaction; Rats; Rats, Transgenic; Receptors, Angiotensin; Renin; Renin-Angiotensin System

To observe different effects of acetoacetate extract of Radix Aconite and Radix Aconite Decoction on the energy metabolism in deficient cold model rats.. Wistar rats were randomly divided into the blank control group (n=10) and the deficient cold model group (n=30). The deficient cold rat model was established using decoction consisting of gypsum, Radix Gentianae, Cortex Phellodendri, and Rhizoma Anemarrhenae. The decoction was given to rats of the deficient cold model group by gastrogavage for 5 days. Then these rats were randomly divided into the acetoacetate extract of Radix Aconite group (n=10), the Radix Aconite Decoction group (n=10), and the model group (n=10). Rats in the model model group were administered with the decoction by gastrogavage. Rats in the other two groups were administered with the acetoacetate extract of Radix Aconite or Radix Aconite Decoction by gastrogavage for 5 days. The contents of lactic acid (LA), lactate dehydrogenase (LDH), pyruvate (PA), glycogen (Gn) and activities of Na(+) -K(+) -ATPase and Ca(2+) -Mg(2+) -ATPase in the hepatic tissue were detected.. Compared with the blank control group, the PA content, activities of Na(+)-K(+) -ATPase and Ca(2+) -Mg(2+) -ATPase decreased in the model group. Compared with the model group, the PA content increased in the other two groups. Compared with the control group, the contents of LDH and PA, and activities of Na(+) -K(+) -ATPase increased in the the acetoacetate extract of Radix Aconite group with statistical difference (P < 0.05).. The febricity of acetoacetate extract of Radix Aconite was slightly higher than that of Radix Aconite Decoction, seemingly generating more energy. But the final conclusions and concrete mechanisms of action need further studies.

Topics: Acetoacetates; Adenosine Triphosphatases; Animals; Disease Models, Animal; Diterpenes; Drugs, Chinese Herbal; Energy Metabolism; Female; Glycogen; L-Lactate Dehydrogenase; Lactic Acid; Liver; Male; Plant Extracts; Pyruvic Acid; Rats; Rats, Wistar

We investigated if alterations in the insulin-signaling pathway could contribute to reduced hepatic glycogen levels in adult rats subjected to a protein deficiency during intrauterine life and lactation and reared through to recovery on a soybean diet.. Rats from mothers fed with 17% or 6% protein (casein) during pregnancy and lactation were maintained with a 17% casein diet (offspring born to and suckled by mothers fed a control diet and subsequently fed the same diet after weaning [CC group] and offspring born to and suckled by mothers fed a control diet and subsequently fed a soybean flour diet with 17% protein after weaning [CS group]), a soybean diet (offspring of mothers fed a low-protein diet and a control diet after weaning [LC group] and offspring of mothers fed a low-protein diet and fed a soybean flour diet containing 17% protein after weaning [LS group]), or a 6% casein diet (offspring of mothers fed a low-protein diet and subsequently fed the same diet after weaning [LL group]) from weaning until 90 d of life.. A soybean diet did not modify basal serum glucose and glucagon concentrations, but raised basal serum insulin and consequently increased the serum insulin/glucose ratio. Insulin receptor and insulin receptor substrate-1 levels were lower in rats fed a soybean diet compared with those maintained with a casein diet. In the LS group, the p85 levels were higher than in the LC group, whereas in CS rats its expression was lower than in CC rats. The expression of p110 was lower in the CS group compared with the CC group and similar in the LS and LC groups. Insulin receptor substrate-1 phosphorylation was similar in the LS, LC, and CS groups and lower compared with the CC group. The insulin receptor substrate-1-p85/phosphatidylinositol 3-kinase association was lower in LS than in LC rats and in CS than in CC rats. Akt phosphorylation was lower in the CS and LS groups than in the CC and LC groups.. Adult rats maintained with a soybean diet exhibited insulin resistance due, at least in part, to alterations in the early steps of the insulin signal transduction pathway.

Topics: Analysis of Variance; Animal Nutritional Physiological Phenomena; Animals; Blood Glucose; Blotting, Western; Body Weight; Caseins; Diet; Disease Models, Animal; Female; Glycine max; Glycogen; Insulin; Insulin Resistance; Lactation; Liver; Male; Pregnancy; Prenatal Nutritional Physiological Phenomena; Protein-Energy Malnutrition; Rats; Rats, Wistar

Caveolin, a member of the membrane-anchoring protein family, accumulates various growth receptors in caveolae and inhibits their function. Upregulation of caveolin attenuates cellular proliferation and growth. However, the role of caveolin in regulating insulin signals remains controversial. Here, we demonstrate that caveolin potently enhances insulin receptor (IR) signaling when overexpressed in the liver in vivo. Adenovirus-mediated gene transfer was used to overexpress caveolin specifically in the liver of diabetic obese mice, which were generated with a high-fat diet. Expression of molecules involved in IR signaling, such as IR or Akt, remained unchanged after gene transfer. However, hepatic glycogen synthesis was markedly increased with a decrease in phosphoenolpyruvate carboxykinase protein expression. Insulin sensitivity was increased after caveolin gene transfer as determined by decreased blood glucose levels in response to insulin injection and fasting blood glucose levels. Glucose tolerant test performance was also improved. Similar improvements were obtained in KKA(y) genetically diabetic mice. Adenovirus-mediated overexpression of caveolin-3 in hepatic cells also enhanced IR signaling, as shown by increased phosphorylation of IR in response to insulin stimulation and higher glycogen synthesis at baseline. These effects were attributed mostly to increased insulin receptor activity and caveolin-mediated, direct inhibition of protein tyrosine phosphatase 1B, which was increased in obese mouse livers. In conclusion, our results suggest that caveolin is an important regulator of glucose metabolism that can enhance insulin signals.

Topics: Adenoviridae; Age Factors; Aging; Animals; Blood Glucose; Caveolin 3; Diabetes Mellitus, Type 2; Dietary Fats; Disease Models, Animal; Gene Transfer Techniques; Genetic Vectors; Glucose Tolerance Test; Glycogen; Hep G2 Cells; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Liver; Mice; Obesity; Phosphoenolpyruvate Carboxykinase (GTP); Phosphorylation; Protein Tyrosine Phosphatase, Non-Receptor Type 1; Rats; Receptor, Insulin; Signal Transduction

It has been suggested that thiazolidinediones (TZDs) ameliorate insulin resistance in muscle tissue by suppressing muscle lipid storage and the activity of novel protein kinase C (nPKC) isoforms. To test this hypothesis, we analyzed long-term metabolic effects of pioglitazone and the activation of nPKC-epsilon and -theta isoforms in an animal model of the metabolic syndrome, the spontaneously hypertensive rat (a congenic SHR strain with wild type Cd36 gene) fed a diet with 60 % sucrose from the age of 4 to 8 months. Compared to untreated controls, pioglitazone treatment was associated with significantly increased basal (809+/-36 vs 527+/-47 nmol glucose/g/2h, P<0.005) and insulin-stimulated glycogenesis (1321+/-62 vs 749+/-60 nmol glucose/g/2h, P<0.0001) in isolated gastrocnemius muscles despite increased concentrations of muscle triglycerides (3.83+/-0.33 vs 2.25+/-0.12 micromol/g, P<0.005). Pioglitazone-treated rats exhibited significantly increased membrane/total (cytosolic plus membrane) ratio of both PKC-epsilon and PKC-theta isoforms compared to untreated controls. These results suggest that amelioration of insulin resistance after long-term pioglitazone treatment is associated with increased activation of PKC-epsilon and -theta isoforms in spite of increased lipid concentration in skeletal muscles.

Topics: Animals; Animals, Congenic; Blood Glucose; CD36 Antigens; Dietary Sucrose; Disease Models, Animal; Glycogen; Hypoglycemic Agents; Insulin; Insulin Resistance; Isoenzymes; Male; Metabolic Syndrome; Muscle, Skeletal; Pioglitazone; Protein Kinase C; Protein Kinase C-epsilon; Protein Kinase C-theta; Protein Transport; Rats; Rats, Inbred SHR; Thiazolidinediones; Time Factors; Triglycerides

Glycogen storage disease type II (GSDII) or Pompe disease is an autosomal recessive disorder caused by acid alpha-glucosidase (GAA) deficiency, leading to lysosomal glycogen accumulation. Affected individuals store glycogen mainly in cardiac and skeletal muscle tissues resulting in fatal hypertrophic cardiomyopathy and respiratory failure in the most severe infantile form. Enzyme replacement therapy has already proved some efficacy, but results remain variable especially in skeletal muscle. Substrate reduction therapy was successfully used to improve the phenotype in several lysosomal storage disorders. We have recently demonstrated that shRNA-mediated reduction of glycogen synthesis led to a significant reduction of glycogen accumulation in skeletal muscle of GSDII mice. In this paper, we analyzed the effect of a complete genetic elimination of glycogen synthesis in the same GSDII model. GAA and glycogen synthase 1 (GYS1) KO mice were inter-crossed to generate a new double-KO model. GAA/GYS1-KO mice exhibited a profound reduction of the amount of glycogen in the heart and skeletal muscles, a significant decrease in lysosomal swelling and autophagic build-up as well as a complete correction of cardiomegaly. In addition, the abnormalities in glucose metabolism and insulin tolerance observed in the GSDII model were corrected in double-KO mice. Muscle atrophy observed in 11-month-old GSDII mice was less pronounced in GAA/GYS1-KO mice, resulting in improved exercise capacity. These data demonstrate that long-term elimination of muscle glycogen synthesis leads to a significant improvement of structural, metabolic and functional defects in GSDII mice and offers a new perspective for the treatment of Pompe disease.

Topics: alpha-Glucosidases; Animals; Disease Models, Animal; Female; Glucose; Glycogen; Glycogen Storage Disease Type II; Glycogen Synthase; Humans; Lysosomes; Male; Mice; Mice, Knockout; Muscle, Skeletal

Glycogen synthase kinase-3 (GSK-3) is a multi-functional kinase that regulates signalling pathways affecting glycogen metabolism, protein synthesis, mitosis, and apoptosis. GSK-3 inhibition limits cardiac ischaemia-reperfusion (IR) injury, but mechanisms are not clearly defined. This study tested the hypothesis that acute GSK-3 inhibition stimulates glycogen synthesis, repartitions glucose away from glycolysis, reduces proton (H+) production from glucose metabolism, and attenuates intracellular Ca2+ (Ca2+(i)) overload.. In isolated perfused working rat hearts subjected to global ischaemia and reperfusion, the selective GSK-3 inhibitor, SB-216763 (SB, 3 micromol/L), when added either prior to ischaemia or at the onset of reperfusion, improved recovery of left-ventricular (LV) work. SB increased glycogen synthesis during reperfusion while glycolysis and H+ production were reduced. Rates of glucose and palmitate oxidation were improved by SB. Measurement of Ca2+(i) concentration by rapid acquisition indo-1 fluorescence imaging showed that SB, when added either prior to ischaemia or at the onset of reperfusion, reduced diastolic Ca2+(i) overload during reperfusion. In aerobic hearts depleted of glycogen by substrate-free perfusion to a level similar to that measured at the onset of reperfusion, SB accelerated glycogen synthesis and reduced glycolysis and H+ production independent of changes in LV work.. Our study indicates that reduction in H+ production by GSK-3 inhibition is an early and upstream event that lessens Ca2+(i) overload during ischaemia and early reperfusion independent of LV work which enhances the recovery of post-ischaemic LV function and that may ultimately contribute to previously observed reductions in cell death and infarction.

Topics: Animals; Calcium; Cardiotonic Agents; Disease Models, Animal; Down-Regulation; Glucose; Glycogen; Glycogen Synthase Kinase 3; Glycolysis; Hydrogen-Ion Concentration; In Vitro Techniques; Indoles; Male; Maleimides; Myocardial Reperfusion Injury; Myocardium; Palmitic Acid; Perfusion; Protein Kinase Inhibitors; Rats; Rats, Sprague-Dawley; Recovery of Function; Sodium-Calcium Exchanger; Sodium-Hydrogen Exchangers; Time Factors; Up-Regulation; Ventricular Function, Left

Protein hepatocyte nuclear factor 4alpha (HNF-4alpha) is atypically activated in the liver of diabetic rodents and contributes to hepatic glucose production. HNF-4alpha and Foxo1 can physically interact with each other and represent an important signal transduction pathway that regulates the synthesis of glucose in the liver. Foxo1 and HNF-4alpha interact with their own binding sites in the phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) promoters, and this binding is required for their effects on those promoters. However, the effect of physical activity on the HNF-4alpha/Foxo1 pathway is currently unknown. Here, we investigate the protein levels of HNF-4alpha and the HNF-4alpha/Foxo1 pathway in the liver of leptin-deficient (ob/ob) and diet-induced obese Swiss (DIO) mice after acute exercise. The ob/ob and DIO mice swam for four 30 min periods, with 5 min rest intervals for a total swimming time of 2h. Eight hours after the acute exercise protocol, the mice were submitted to an insulin tolerance test (ITT) and determination of biochemical and molecular parameters. Acute exercise improved insulin signalling, increasing insulin-stimulated Akt and Foxo1 phosphorylation and decreasing HNF-4alpha protein levels in the liver of DIO and ob/ob mice under fasting conditions. These phenomena were accompanied by a reduction in the expression of gluconeogenesis genes, such as PEPCK and G6Pase. Importantly, the PI3K inhibitor LY292004 reversed the acute effect of exercise on fasting hyperglycaemia, confirming the involvement of the PI3K pathway. The present study shows that exercise acutely improves the action of insulin in the liver of animal models of obesity and diabetes, resulting in increased phosphorylation and nuclear exclusion of Foxo1, and a reduction in the Foxo1/HNF-4alpha pathway. Since nuclear localization and the association of these proteins is involved in the activation of PEPCK and G6Pase, we believe that the regulation of Foxo1 and HNF-4alpha activities are important mechanisms involved in exercise-induced improvement of glucose homeostasis in insulin resistant states.

Topics: Active Transport, Cell Nucleus; Animals; Diabetes Mellitus; Disease Models, Animal; Down-Regulation; Forkhead Box Protein O1; Forkhead Transcription Factors; Glucose; Glucose Clamp Technique; Glucose-6-Phosphatase; Glycogen; Hepatocyte Nuclear Factor 4; Insulin; Insulin Resistance; Liver; Male; Mice; Obesity; Phosphatidylinositol 3-Kinases; Phosphoenolpyruvate Carboxykinase (GTP); Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Physical Exertion; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Signal Transduction; Swimming

The metabolic profile is very affected in sepsis, which is the most important cause of extrapulmonary acute lung injury (ALI-EX). The aim of the present study was to investigate whether sepsis-induced ALI-EX in mice affects the glycogen content in different tissues. This measurement could indicate performance limitations of tissues and constitute a novel biochemical aspect of ALI. ALI was induced by cecal ligation and puncture (CLP), which is a model that reproduces clinical and pathological alterations stemming from sepsis. Control group mice were sham-operated. Glycogen content (mg/g tissue) from different tissues was measured using the anthrone reagent. Glycogen content in the diaphragm (0.3 +/- 0.1) and gastrocnemius muscle (0.4 +/- 0.1) was lower in the sepsis group than the control group (0.9 +/- 0.1 and 1.1 +/- 0.2, respectively). However, there were no significant differences in glycogen content in the heart and kidney. Sepsis caused a greater thickening of the alveolar walls, more areas of atelectasis, and a greater abundance of inflammatory cells in comparison to the control group. These results demonstrate that glycogen content in sepsis-induced ALI-EX is altered in different tissues.

Topics: Acute Lung Injury; Animals; Diaphragm; Disease Models, Animal; Glycogen; Kidney; Lung; Male; Mice; Mice, Inbred BALB C; Muscle, Skeletal; Myocardium; Sepsis

Cardiac dysfunction is a major cause of morbidity and mortality in patients with end-stage liver disease; yet the mechanisms remain largely unknown. We hypothesized that the complex interrelated impairments in cardiac structure and function secondary to progression of liver diseases involve alterations in signaling pathways engaged in cardiac energy metabolism and hypertrophy, augmented by direct effects of high circulating levels of bile acids. Biliary fibrosis was induced in male C57BL/6J mice by feeding a 0.1% 3,5-diethoxycarbonyl-1,4-dihydroxychollidine (DDC) supplemented diet. After 3 weeks, mice underwent live imaging (dual energy x-ray absorptiometry [DEXA] scanning, two-dimensional echocardiography [2DE], electrocardiography, cardiac magnetic resonance imaging), exercise treadmill testing, and histological and biochemical analyses of livers and hearts. Compared with chow-fed mice, DDC-fed mice fatigued earlier on the treadmill, with reduced VO(2). Marked changes were identified electrophysiologically (bradycardia and prolonged QT interval) and functionally (hyperdynamic left ventricular [LV] contractility along with increased LV thickness). Hearts of DDC-fed mice showed hypertrophic signaling (activation of v-akt murine thymoma viral oncogene/protein kinase B [AKT], inhibition of glycogen synthase kinase-3beta [GSK3beta], a 20-fold up-regulation of beta myosin heavy chain RNA and elevated G(s)alpha/G(i)alpha ratio. Genes regulating cardiac fatty acid oxidation pathways were suppressed, along with a threefold increase in myocardial glycogen content. Treatment of mouse cardiomyocytes (which express the membrane bile acid receptor TGR5) with potent natural TGR5 agonists, taurochenodeoxycholic acid and lithocholic acid, activated AKT and inhibited GSK3beta, similar to the changes seen in DDC-fed mouse hearts. This provides support for a novel mechanism whereby circulating natural bile acids can induce signaling pathways in heart associated with hypertrophy.. Three weeks of DDC feeding-induced biliary fibrosis leads to multiple functional, metabolic, electrophysiological, and hypertrophic adaptations in the mouse heart, recapitulating some of the features of human cirrhotic cardiomyopathy.

Topics: Animals; Bile Acids and Salts; Bile Duct Diseases; Cardiomyopathy, Hypertrophic; Dicarbethoxydihydrocollidine; Disease Models, Animal; Fatigue; Fatty Acids; Fibrosis; Gene Expression; Glycogen; Heart; Male; Mice; Mice, Inbred C57BL; Myocardium; Oxygen Consumption; Phenotype; Receptors, Adrenergic, beta; Receptors, G-Protein-Coupled; Respiratory Function Tests; Signal Transduction

Cassia auriculata traditionally has been used to treat diabetes from ancient times. The objective of the present study was to investigate the mechanism of action for the antidiabetic activity of aqueous leaf extract of C. auriculata (CLEt) in streptozotocin-induced mildly diabetic (MD) and severely diabetic (SD) rats. CLEt was orally administered to MD and SD rats at a dose of 400 mg/kg once a day for 15 days. CLEt-treated MD and SD rats showed significant reduction in fasting blood glucose. Assessment of plasma insulin and C-peptide following treatment with CLEt revealed significant elevation in their levels. Administration of CLEt enhanced the activity of hepatic hexokinase and phosphofructokinase and suppressed glucose-6-phosphatase and fructose-1,6-bisphosphatase in both MD and SD rats. A significant rise in glycogen content was also observed in both liver and muscles of CLEt-fed MD and SD rats. Histopathological examination of pancreatic sections revealed increased number of islets and beta-cells in CLEt-treated MD as well as SD rats. The findings of the study suggest that the antidiabetic effect of CLEt could be due to its insulinogenic action. In addition, impaired glucose homeostasis was improved by feeding the extract through amelioration in the carbohydrate metabolic pathways. Thus, the extract may exert an antidiabetic effect through pancreatic as well as extrapancreatic action.

Topics: Animals; Blood Glucose; C-Peptide; Cassia; Diabetes Mellitus; Disease Models, Animal; Glucose; Glycogen; Humans; Hypoglycemic Agents; Insulin; Liver; Male; Muscle, Skeletal; Plant Extracts; Plant Leaves; Random Allocation; Rats; Rats, Sprague-Dawley; Rats, Wistar; Streptozocin

Transforming growth factor-beta (TGF-beta) plays a pivotal role in liver fibrosis, because it activates hepatic stellate cells, stimulating extracellular matrix deposition. Cyclooxygenase-2 (COX-2) has been associated with TGF-beta because its inhibition decreases TGF-beta expression and collagen production in some cultured cell types.. The aim of this work was to evaluate the ability of celecoxib (a selective COX-2 inhibitor) to prevent and to reverse the liver fibrosis induced by CCl(4).. We established experimental groups of rats including vehicle and drug controls, damage induced by chronic CCl(4) administration and CCl(4) plus pharmacological treatment in both prevention and reversion models. We determined: alanine aminotransferase, alkaline phosphatase, gamma-glutamyl transpeptidase, COX and metalloproteinase-2 and -9 activities, lipid peroxidation, glutathione levels, glycogen and collagen content and TGF-beta expression.. Celecoxib prevented and aided to the recovery of livers with necrotic and cholestatic damage. Celecoxib exhibited anti-oxidant properties by restoring the redox equilibrium (lipid peroxidation and glutathione levels). Glycogen was decreased by CCl(4), while celecoxib partially prevented and reversed this effect. Celecoxib inhibited COX-2 activity, decreased TGF-beta expression, induced metalloproteinase-2 activity and, consequently, prevented and reversed collagen accumulation.. Our findings indicate that celecoxib exerts strong antifibrogenic and fibrolytic effects in the CCl(4) model of cirrhosis.

Topics: Alanine Transaminase; Animals; Anti-Inflammatory Agents; Antioxidants; Aspartate Aminotransferases; Carbon Tetrachloride; Celecoxib; Chemical and Drug Induced Liver Injury; Collagen; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Disease Models, Animal; gamma-Glutamyltransferase; Glutathione; Glycogen; Liver; Liver Cirrhosis; Male; Malondialdehyde; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Pyrazoles; Rats; Rats, Wistar; Sulfonamides; Time Factors; Transforming Growth Factor beta

Due to the lack of acid alpha-glucosidase (GAA) activity, Pompe mice develop glycogen storage pathology and progressive skeletal muscle dysfunction with age. Applying either gene or enzyme therapy to reconstitute GAA levels in older, symptomatic Pompe mice effectively reduces glycogen storage in skeletal muscle but provides only modest improvements in motor function. As strategies to stimulate muscle hypertrophy, such as by myostatin inhibition, have been shown to improve muscle pathology and strength in mouse models of muscular dystrophy, we sought to determine whether these benefits might be similarly realized in Pompe mice. Administration of a recombinant adeno-associated virus serotype 8 vector encoding follistatin, an inhibitor of myostatin, increased muscle mass and strength but only in Pompe mice that were treated before 10 months of age. Younger Pompe mice showed significant muscle fiber hypertrophy in response to treatment with follistatin, but maximal gains in muscle strength were achieved only when concomitant GAA administration reduced glycogen storage in the affected muscles. Despite increased grip strength, follistatin treatment failed to improve rotarod performance. These findings highlight the importance of treating Pompe skeletal muscle before pathology becomes irreversible, and suggest that adjunctive therapies may not be effective without first clearing skeletal muscle glycogen storage with GAA.

Topics: alpha-Glucosidases; Animals; Body Mass Index; Dependovirus; Disease Models, Animal; Follistatin; Genetic Vectors; Glycogen; Glycogen Storage Disease Type II; Humans; Mice; Mice, Inbred C57BL; Muscle, Skeletal

The main energy reserve of the brain is glycogen, which is almost exclusively localized in astrocytes. We previously reported that cerebral expression of certain genes related to glycogen metabolism changed following instrumental sleep deprivation in mice. Here, we extended our investigations to another set of genes related to glycogen and glucose metabolism. We also compared the effect of instrumentally and pharmacologically induced prolonged wakefulness, followed (or not) by 3 hours of sleep recovery, on the expression of genes related to brain energy metabolism.. Sleep deprivation for 6-7 hours.. Animal sleep research laboratory.. Adults OF1 mice.. Wakefulness was maintained by "gentle sleep deprivation" method (GSD) or by administration of the wakefulness-promoting drug modafinil (MOD) (200 mg/kg i.p.).. Levels of mRNAs encoding proteins related to energy metabolism were measured by quantitative real-time PCR in the cerebral cortex. The mRNAs encoding protein targeting to glycogen (PTG) and the glial glucose transporter were significantly increased following both procedures used to prolong wakefulness. Glycogenin mRNA levels were increased only after GSD, while neuronal glucose transporter mRNA only after MOD. These effects were reversed after sleep recovery. A significant enhancement of glycogen synthase activity without any changes in glycogen levels was observed in both conditions.. These results indicate the existence of a metabolic adaptation of astrocytes aimed at maintaining brain energy homeostasis during the sleep-wake cycle.

Topics: Animals; Benzhydryl Compounds; Central Nervous System Stimulants; Cerebral Cortex; Disease Models, Animal; Energy Metabolism; Gene Expression; Glucose Transport Proteins, Facilitative; Glucosyltransferases; Glycogen; Glycogen Synthase; Glycoproteins; Male; Mice; Modafinil; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Sleep Deprivation; Wakefulness

to evaluate the effectiveness of the IUGR model by uterine artery ligation mimicking placental insufficiency in rats.. sprague-Dawley rat fetuses were divided into three groups: IUGR (intrauterine growth restriction), with fetuses in the right horn of pregnant rats subjected to right uterine artery ligation at 18.5 days of gestation (term = 22 days); C-IUGR (control of restriction), with control fetuses in the left horn, and EC (external control), with fetuses of intact rats. Animals were harvested by cesarean section at day 21.5 days of gestation. Fetuses were weighed and then sacrificed. The intestine, liver, kidney and placenta were weighed and dissected for morphometric and histological analysis.. the morphometric data showed decreased body weight (BW), liver weight (LW) and intestinal weight (IW) of fetuses with IUGR compared to C-IUGR and EC (p<0.001). The placental weight (PW), renal weight (RW) and LW/BW, IW/BW, and RW/BW ratios did not change. IUGR fetuses had decreased kidney thickness (p<0.001) and decreased thickness of the intestinal mucosa and submucosa (p<0.05). Histological evaluation showed reduction of liver glycogen storage in fetuses with IUGR compared to C-IUGR and CE.. the model described was efficient and caused symmetric fetal IUGR with decreased size of most organs, especially the liver, and changes in glycogen stores.

Topics: Animals; Disease Models, Animal; Fetal Growth Retardation; Glycogen; Intestines; Kidney; Liver; Organ Size; Rats; Rats, Sprague-Dawley

Topics: Active Transport, Cell Nucleus; Animals; Diabetes Mellitus; Disease Models, Animal; Down-Regulation; Forkhead Box Protein O1; Forkhead Transcription Factors; Glucose; Glucose Clamp Technique; Glucose-6-Phosphatase; Glycogen; Hepatocyte Nuclear Factor 4; Insulin; Insulin Resistance; Liver; Male; Mice; Obesity; Phosphatidylinositol 3-Kinases; Phosphoenolpyruvate Carboxykinase (GTP); Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Physical Exertion; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Signal Transduction; Swimming

The objective of this study was to analyze the aerobic capacity, through the maximal lactate steady-state (MLSS) protocol, of rats subjected to fetal protein malnutrition and recovered with a fructose-rich diet. Pregnant adult Wistar rats that were fed a balanced (17% protein) diet or a low-protein (6% protein) diet were used. After birth, the offspring were distributed into groups according to diet until 60 days of age: balanced (B), balanced diet during the whole experimental period; balanced-fructose (BF), balanced diet until birth and fructose-rich diet (60% fructose) until 60 days; low protein-balanced (LB), low-protein diet until birth and balanced diet until 60 days; and low protein-fructose (LF), low protein diet until birth and fructose-rich diet until 60 days. It was verified that the fructose-rich diet reduced body growth, mainly in the BF group. There was no difference among the groups in the load corresponding to the MLSS (B, 7.5+/-0.5%; BF, 7.4+/-0.6%; LB, 7.7+/-0.4%; and LF, 7.7+/-0.6% relative to body weight). However, the BF group presented higher blood lactate concentrations (4.8+/-0.9 mmol.L(-1)) at 25 min in the load corresponding to the MLSS (B, 3.2+/-0.9 mmol.L(-1); LB, 3.4+/-0.9 mmol.L(-1); and LF, 3.2+/-1.0 mmol.L(-1)). Taken together, these results indicate that the ability of young rats to perform exercise was not altered by intrauterine malnutrition or a fructose-rich diet, although the high fructose intake after the balanced diet in utero increased blood lactate during swimming exercises in rats.

Topics: Age Factors; Animal Nutritional Physiological Phenomena; Animals; Blood Glucose; Body Weight; Diet, Protein-Restricted; Dietary Proteins; Dietary Sucrose; Disease Models, Animal; Exercise Tolerance; Female; Fetal Nutrition Disorders; Glycogen; Kinetics; Lactic Acid; Liver; Male; Maternal Nutritional Physiological Phenomena; Pregnancy; Prenatal Exposure Delayed Effects; Protein-Energy Malnutrition; Rats; Rats, Wistar; Recovery of Function; Serum Albumin; Swimming

Autophagy, an intracellular system for delivering portions of cytoplasm and damaged organelles to lysosomes for degradation/recycling, plays a role in many physiological processes and is disturbed in many diseases. We recently provided evidence for the role of autophagy in Pompe disease, a lysosomal storage disorder in which acid alphaglucosidase, the enzyme involved in the breakdown of glycogen, is deficient or absent. Clinically the disease manifests as a cardiac and skeletal muscle myopathy. The current enzyme replacement therapy (ERT) clears lysosomal glycogen effectively from the heart but less so from skeletal muscle. In our Pompe model, the poor muscle response to therapy is associated with the presence of pools of autophagic debris. To clear the fibers of the autophagic debris, we have generated a Pompe model in which an autophagy gene, Atg7, is inactivated in muscle. Suppression of autophagy alone reduced the glycogen level by 50–60%. Following ERT, muscle glycogen was reduced to normal levels, an outcome not observed in Pompe mice with genetically intact autophagy. The suppression of autophagy, which has proven successful in the Pompe model, is a novel therapeutic approach that may be useful in other diseases with disturbed autophagy.

Topics: alpha-Glucosidases; Animals; Apoptosis Regulatory Proteins; Autophagy; Beclin-1; Disease Models, Animal; Enzyme Replacement Therapy; Glycogen; Glycogen Storage Disease Type II; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Integrases; Mice; Muscle Fibers, Fast-Twitch; Myosin Light Chains; Phosphorylation; Ubiquitin

The goal of the present study was to assess the effects of a restricted feeding schedule (RFS) on postischemic contractile recovery in relation to triacylglycerol (TAG), glycogen, and ATP content. Glucose-6-phosphate dehydrogenase (G6PDH) activity, reduced/oxidized glutathione ratio (GSH/GSSG), and thiobarbituric acid reactive substances (TBARS) levels were also determined. Isolated rat hearts entrained to daily RFS (2 h food access starting at 1200) or fed ad libitum (FED) for 3 weeks were Langendorff-perfused (25 min ischemia, 30 min reperfusion) with Krebs-Ringer bicarbonate solution (10 mmol/L glucose). RFS improved the recovery of contractility and reduced creatine kinase (CK) release upon reperfusion. Further, at the end of reperfusion, RFS hearts exhibited increased G6PDH activity and repletion of tissue glycogen, TAG, and ATP that was not observed in the FED hearts. GSH/GSSG at the end of reperfusion fell to the same value in both nutritional states, and TBARS levels were higher in the RFS hearts. In conclusion, RFS improved postischemic functional recovery, which was accompanied by a reduction in CK release and a striking energy recovery. Although enhanced G6PDH activity was displayed, RFS was unable to reduce lipid peroxidation, supporting a clear dissociation between protection against mechanical dysfunction and CK release on the one hand and oxidative damage on the other.

Topics: Adenosine Triphosphate; Animals; Caloric Restriction; Creatine Kinase; Disease Models, Animal; Female; Glucosephosphate Dehydrogenase; Glutathione; Glycogen; Heart Function Tests; Heart Ventricles; Lipid Peroxidation; Myocardial Contraction; Myocardial Ischemia; Perfusion; Rats; Rats, Wistar; Triglycerides; Ventricular Function, Left

Lysosomal storage disorders such as Pompe disease can be more effectively treated, if immune tolerance to enzyme or gene replacement therapy can be achieved. Alternatively, immune responses against acid α-glucosidase (GAA) might be evaded in Pompe disease through muscle-specific expression of GAA with adeno-associated virus (AAV) vectors.. An AAV vector containing the MHCK7 regulatory cassette to drive muscle-specific GAA expression was administered to GAA knockout (KO) mice, immune tolerant GAA-KO mice and mannose-6-phosphate deficient GAA-KO mice. GAA activity and glycogen content were analyzed in striated muscle to determine biochemical efficacy.. The biochemical efficacy from GAA expression was slightly reduced in GAA-KO mice, as demonstrated by higher residual glycogen content in skeletal muscles. Next, immune tolerance to GAA was induced in GAA-KO mice by co-administration of a second AAV vector encoding liver-specific GAA along with the AAV vector encoding muscle-specific GAA. Antibody formation was prevented by liver-specific GAA, and the biochemical efficacy of GAA expression was improved in the absence of antibodies, as demonstrated by significantly reduced glycogen content in the diaphragm. Efficacy was reduced in old GAA-KO mice despite the absence of antibodies. The greatest impact upon gene therapy was observed in GAA-KO mice lacking the mannose-6-phosphate receptor in muscle. The clearance of stored glycogen was markedly impaired despite high GAA expression in receptor-deficient Pompe disease mice.. Overall, antibody formation had a subtle effect upon efficacy, whereas the absence of mannose-6-phosphate receptors markedly impaired muscle-targeted gene therapy in murine Pompe disease.

Topics: alpha-Glucosidases; Animals; Antibody Formation; Dependovirus; Disease Models, Animal; Gene Expression Regulation; Genetic Therapy; Genetic Vectors; Glycogen; Glycogen Storage Disease Type II; Mice; Mice, Knockout; Muscle, Skeletal; Receptor, IGF Type 2; Transgenes

Glycogen, the largest cytosolic macromolecule, acquires solubility, essential to its function, through extreme branching. Lafora bodies are aggregates of polyglucosan, a long, linear, poorly branched, and insoluble form of glycogen. Lafora bodies occupy vast numbers of neuronal dendrites and perikarya in Lafora disease in time-dependent fashion, leading to intractable and fatal progressive myoclonus epilepsy. Lafora disease is caused by deficiency of either the laforin glycogen phosphatase or the malin E3 ubiquitin ligase. The 2 leading hypotheses of Lafora body formation are: (1) increased glycogen synthase activity extends glycogen strands too rapidly to allow adequate branching, resulting in polyglucosans; and (2) increased glycogen phosphate leads to glycogen conformational change, unfolding, precipitation, and conversion to polyglucosan. Recently, it was shown that in the laforin phosphatase-deficient form of Lafora disease, there is no increase in glycogen synthase, but there is a dramatic increase in glycogen phosphate, with subsequent conversion of glycogen to polyglucosan. Here, we determine whether Lafora bodies in the malin ubiquitin ligase-deficient form of the disease are due to increased glycogen synthase or increased glycogen phosphate.. We generated malin-deficient mice and tested the 2 hypotheses.. Malin-deficient mice precisely replicate the pathology of Lafora disease with Lafora body formation in skeletal muscle, liver, and brain, and in the latter in the pathognomonic perikaryal and dendritic locations. Glycogen synthase quantity and activity are unchanged. There is a highly significant increase in glycogen phosphate.. We identify a single common modification, glycogen hyperphosphorylation, as the root cause of Lafora body pathogenesis.

Topics: Animals; Brain; Cerebellar Cortex; Disease Models, Animal; Dual-Specificity Phosphatases; Gene Expression Regulation; Glycogen; Glycogen Synthase; Hyperphosphatemia; Inclusion Bodies; Lafora Disease; Mice; Mice, Knockout; Muscle, Skeletal; Phosphates; Protein Tyrosine Phosphatases, Non-Receptor

PGC-1α is a transcriptional co-activator that plays a central role in the regulation of energy metabolism. Our interest in this protein was driven by its ability to promote muscle remodeling. Conversion from fast glycolytic to slow oxidative fibers seemed a promising therapeutic approach in Pompe disease, a severe myopathy caused by deficiency of the lysosomal enzyme acid alpha-glucosidase (GAA) which is responsible for the degradation of glycogen. The recently approved enzyme replacement therapy (ERT) has only a partial effect in skeletal muscle. In our Pompe mouse model (KO), the poor muscle response is seen in fast but not in slow muscle and is associated with massive accumulation of autophagic debris and ineffective autophagy. In an attempt to turn the therapy-resistant fibers into fibers amenable to therapy, we made transgenic KO mice expressing PGC-1α in muscle (tgKO). The successful switch from fast to slow fibers prevented the formation of autophagic buildup in the converted fibers, but PGC-1α failed to improve the clearance of glycogen by ERT. This outcome is likely explained by an unexpected dramatic increase in muscle glycogen load to levels much closer to those observed in patients, in particular infants, with the disease. We have also found a remarkable rise in the number of lysosomes and autophagosomes in the tgKO compared to the KO. These data point to the role of PGC-1α in muscle glucose metabolism and its possible role as a master regulator for organelle biogenesis - not only for mitochondria but also for lysosomes and autophagosomes. These findings may have implications for therapy of lysosomal diseases and other disorders with altered autophagy.

Topics: Animals; Autophagy; Disease Models, Animal; Glucose; Glycogen; Glycogen Storage Disease Type II; Golgi Apparatus; Humans; Lysosomes; Mice; Mice, Knockout; Mice, Transgenic; Muscle, Skeletal; Muscles; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; Trans-Activators; Transcription Factors

Autophagy is an intracellular pathway that contributes to the degradation and recycling of unfolded proteins. Based on the knowledge that autophagy affects glycogen metabolism and that alpha(1)-antitrypsin (AAT) deficiency is associated with an autophagic response in the liver, we hypothesized that the conformational abnormalities of the Z-AAT protein interfere with hepatocyte glycogen storage and/or metabolism. Compared with wild-type mice (WT), the Z-AAT mice had lower liver glycogen stores (P < 0.001) and abnormal activities of glycogen-related enzymes, including acid alpha-glucosidase (P < 0.05) and the total glycogen synthase (P < 0.05). As metabolic consequences, PiZ mice demonstrated lower blood glucose levels (P < 0.05), lower body weights (P < 0.001), and lower fat pad weights (P < 0.001) compared with WT. After the stress of fasting or partial hepatectomy, PiZ mice had further reduced liver glycogen and lower blood glucose levels (both P < 0.05 compared WT). Finally, PiZ mice exhibited decreased survival after partial hepatectomy (P < 0.01 compared with WT), but this was normalized with postoperative dextrose supplementation. In conclusion, these observations are consistent with the general concept that abnormal protein conformation and degradation affects other cellular functions, suggesting that diseases in the liver might benefit from metabolic compensation if glycogen metabolism is affected.

Topics: alpha 1-Antitrypsin; alpha-Glucosidases; Animals; Autophagy; Blood Glucose; Disease Models, Animal; Glycogen; Glycogen Storage Disease; Glycogen Synthase; Humans; Liver; Liver Diseases; Mice; Mice, Transgenic; Pulmonary Emphysema

Diabetes mellitus is the most common and serious metabolic disorder among people all over the world. Many plants have successfully been used to overcome this problem. Costus speciosus is widely used in Indian medicine to treat various diseases including diabetes. Bioassay guided fractionation was followed to isolate costunolide from the hexane extract of C. speciosus root. The structure was elucidated using X-ray crystallography. Costunolide was administered to streptozotocin (STZ) (50 mg/kg bw)-induced diabetic male wistar rats at different doses (5, 10, 20 mg/kg bw) for 30 days to assess its effect on fasting plasma glucose and cholesterol levels. It was found that plasma glucose was significantly (p<0.05) reduced in a dose-dependent manner when compared to the control. In addition, oral administration of costunolide (20 mg/kg bw) significantly decreased glycosylated hemoglobin (HbA(1c)), serum total cholesterol, triglyceride, LDL cholesterol and at the same time markedly increased plasma insulin, tissue glycogen, HDL cholesterol and serum protein. Also costunolide restored the altered plasma enzyme (aspartate aminotransferase, alanine aminotrasferase, lactate dehydrogenase, alkaline phosphatase and acid phosphatase) levels to near normal. Costunolide might have stimulated the beta islets to secrete insulin by inhibiting the expression of nitric oxide synthase. The results of this experimental study indicated that costunolide possessed normo-glycemic and hypolipidemic activity and hence it could be used as a drug for treating diabetes.

Topics: Animals; Blood Glucose; Blood Proteins; Body Weight; Cholesterol; Costus; Diabetes Mellitus, Experimental; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Glycated Hemoglobin; Glycogen; Hypoglycemic Agents; Insulin; Lipids; Male; Plant Extracts; Plant Roots; Rats; Rats, Wistar; Sesquiterpenes; Streptozocin

The dysregulation of glycogen synthase kinase-3 (GSK3) has been implicated in Alzheimer disease (AD) pathogenesis and in Abeta-induced neurotoxicity, leading us to investigate it as a therapeutic target in an intracerebroventricular Abeta infusion model. Infusion of a specific GSK3 inhibitor SB216763 (SB) reduced a downstream target, phospho-glycogen synthase 39%, and increased glycogen levels 44%, suggesting effective inhibition of enzyme activity. Compared to vehicle, Abeta increased GSK3 activity, and was associated with elevations in levels of ptau, caspase-3, the tau kinase phospho-c-jun N-terminal kinase (pJNK), neuronal DNA fragmentation, and gliosis. Co-infusion of SB corrected all responses to Abeta infusion except the induction of gliosis and behavioral deficits in the Morris water maze. Nevertheless, SB alone was associated with induction of neurodegenerative markers and behavioral deficits. These data support a role for GSK3 hyperactivation in AD pathogenesis, but emphasize the importance of developing inhibitors that do not suppress constitutive activity.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Animals; Caspase 3; Cells, Cultured; Disease Models, Animal; DNA Fragmentation; Enzyme Inhibitors; Gliosis; Glycogen; Glycogen Synthase Kinase 3; Hippocampus; Indoles; JNK Mitogen-Activated Protein Kinases; Maleimides; Maze Learning; Nerve Degeneration; Neurons; Phosphorylation; Rats; Rats, Sprague-Dawley; tau Proteins

Low birth weight is associated with an increased incidence of adult glucose intolerance, type 2 diabetes and cardiovascular disease in humans. In pregnant rats, dietary calorie or protein deprivation results in growth retarded pups, which become glucose intolerant adults with abnormal hepatic glucose metabolism and gluconeogenic enzyme activities. However, whether these abnormalities are present before birth remain unknown.. This study examined the effects of manipulating dietary protein and carbohydrate intake during rat pregnancy on the fetal and maternal hepatic activities of the gluconeogenic enzymes, glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase (PEPCK). Wistar rats were fed ad libitum with either standard chow throughout pregnancy (25% protein, 57% carbohydrate, n=6) or an isocaloric, low protein, high carbohydrate diet (LPHC, 8% protein, 81% carbohydrate) for different periods of pregnancy (early, 0-10 days, n=6; late, 10-20 days, n=7; throughout, 0-20 days, n=6) before tissue collection at day 20. The LPHC diet had no effect on fetal or placental weights, or on fetal hepatic activities of G6Pase and PEPCK in the early LPHC group. In contrast, fetuses of dams fed the LPHC diet in late or throughout pregnancy had lower body and placental weights, and higher hepatic G6Pase and PEPCK activities than controls. Maternal hepatic G6Pase activity was elevated in all LPHC groups, while maternal PEPCK activity was only increased significantly in the late LPHC group.. Feeding a LPHC diet, particularly during late pregnancy, therefore, up-regulates fetal and maternal hepatic glucogenic capacity.

Topics: Animal Nutritional Physiological Phenomena; Animals; Caloric Restriction; Dietary Carbohydrates; Dietary Proteins; Disease Models, Animal; Female; Fetal Weight; Fetus; Gestational Age; Gluconeogenesis; Glucose-6-Phosphatase; Glycogen; Liver; Maternal Nutritional Physiological Phenomena; Phosphoenolpyruvate Carboxykinase (GTP); Placenta; Placentation; Pregnancy; Protein Deficiency; Rats; Rats, Wistar

Obesity is a risk factor for type 2 diabetes in cats. The risk of developing diabetes is severalfold greater for male cats than for females, even after having been neutered early in life. The purpose of this study was to investigate the role of different metabolic pathways in the regulation of endogenous glucose production (EGP) during the fasted state considering these risk factors. A triple tracer protocol using (2)H(2)O, [U-(13)C(3)]propionate, and [3,4-(13)C(2)]glucose was applied in overnight-fasted cats (12 lean and 12 obese; equal sex distribution) fed three different diets. Compared with lean cats, obese cats had higher insulin (P < 0.001) but similar blood glucose concentrations. EGP was lower in obese cats (P < 0.001) due to lower glycogenolysis and gluconeogenesis (GNG; P < 0.03). Insulin, body mass index, and girth correlated negatively with EGP (P < 0.003). Female obese cats had approximately 1.5 times higher fluxes through phosphoenolpyruvate carboxykinase (P < 0.02) and citrate synthase (P < 0.05) than male obese cats. However, GNG was not higher because pyruvate cycling was increased 1.5-fold (P < 0.03). These results support the notion that fasted obese cats have lower hepatic EGP compared with lean cats and are still capable of maintaining fasting euglycemia, despite the well-documented existence of peripheral insulin resistance in obese cats. Our data further suggest that sex-related differences exist in the regulation of hepatic glucose metabolism in obese cats, suggesting that pyruvate cycling acts as a controlling mechanism to modulate EGP. Increased pyruvate cycling could therefore be an important factor in modulating the diabetes risk in female cats.

Topics: Animals; Blood Glucose; Body Mass Index; Body Weight; Carbon Isotopes; Cats; Citrate (si)-Synthase; Citric Acid Cycle; Diabetes Mellitus, Type 2; Diet; Disease Models, Animal; Eating; Fasting; Female; Gluconeogenesis; Glycerol; Glycogen; Glycogenolysis; Indicator Dilution Techniques; Insulin; Liver; Magnetic Resonance Spectroscopy; Male; Obesity; Phosphoenolpyruvate Carboxykinase (GTP); Pyruvic Acid; Sex Factors

Improving the delivery of therapeutics to disease-affected tissues can increase their efficacy and safety. Here, we show that chemical conjugation of a synthetic oligosaccharide harboring mannose 6-phosphate (M6P) residues onto recombinant human acid alpha-glucosidase (rhGAA) via oxime chemistry significantly improved its affinity for the cation-independent mannose 6-phosphate receptor (CI-MPR) and subsequent uptake by muscle cells. Administration of the carbohydrate-remodeled enzyme (oxime-neo-rhGAA) into Pompe mice resulted in an approximately fivefold higher clearance of lysosomal glycogen in muscles when compared to the unmodified counterpart. Importantly, treatment of immunotolerized Pompe mice with oxime-neo-rhGAA translated to greater improvements in muscle function and strength. Treating older, symptomatic Pompe mice also reduced tissue glycogen levels but provided only modest improvements in motor function. Examination of the muscle pathology suggested that the poor response in the older animals might have been due to a reduced regenerative capacity of the skeletal muscles. These findings lend support to early therapeutic intervention with a targeted enzyme as important considerations in the management of Pompe disease.

Topics: alpha-Glucosidases; Animals; Disease Models, Animal; Glycogen; Glycogen Storage Disease Type II; Humans; Mannosephosphates; Mice; Mice, Inbred C57BL; Muscle, Skeletal; Oligosaccharides; Protein Binding; Protein Engineering; Receptor, IGF Type 2

Corticosterone and insulin play complex roles in the amount and composition of calories ingested, and the utilization and deposition of this energy. Understanding the interplay of these two hormones is complicated because increasing concentrations of corticosterone dose-dependently increase circulating insulin levels. We addressed individual contributions of each hormone by controlling, at steady-state levels, corticosterone (by adrenalectomy and exogenous replacement) and insulin (by streptozotocin-induced destruction of pancreatic beta-cells and exogenous replacement) across a spectrum of concentrations in rats, creating 8 hormonal combinations. For 5 days after surgery, all rats received chow. At day 5, they were subdivided into those that continued to receive chow and those that had a choice between chow, lard, and 32% sucrose for a further 5 days. During the choice/chow period, total calories ingested were stimulated by corticosterone and choice diet, and subject to a corticosterone-insulin interaction. Sucrose, but not lard, intake was stimulated by insulin. Body weight was increased by insulin, decreased by high corticosterone, and unaffected by diet. White adipose tissue depot weights were stimulated by insulin, corticosterone, and diet. Plasma triglycerides, free fatty acids, total ketone bodies, glucose, and glycerol were all significantly increased by corticosterone and the choice diet but inhibited by insulin. In contrast, plasma leptin was only increased by insulin and diet, plasma glucagon and liver glycogen was only affected by insulin and liver triglycerides, and arcuate nucleus proopiomelanocortin mRNA was only influenced by diet. Collectively, these data show that corticosterone and insulin determine the intake, form, and compartmentalization of energy both independently and interactively.

Topics: Adrenalectomy; Animals; Arcuate Nucleus of Hypothalamus; Body Weight; Corticosterone; Diabetes Mellitus, Experimental; Disease Models, Animal; Energy Intake; Energy Metabolism; Glycogen; Insulin; Leptin; Liver; Male; Neuropeptide Y; Pro-Opiomelanocortin; Rats; Rats, Sprague-Dawley; Streptozocin; Triglycerides

Thyroid hormone is known to affect myocardial glycogen stores and thereby possibly limit anaerobic performance of mammalian cardiac muscle. Thyroid hormone administration (3,5,3'-triiodo-L-thyroxine, 300 microg/kg/day, sc) for 10 days decreased left ventricle (LV) glycogen concentration relative to euthyroid animals (2.78+/-0.46 vs. 4.28+/-0.29 mg/g of LV (mean+/-SEM)) while increasing the percent of V(1) myosin isozyme, contractile activity and cardiac mass. In contrast, thyroidectomy increased myocardial glycogen stores (8.50+/-0.56 mg/g of LV) and shifted the myosin isozyme toward V(3), prolonged contractile activity and decreased LV mass. Thyroxine administration for 3, 7 and 10 days to thyroidectomized animals progressively decreased contractile duration and increased LV mass. Thyroxine administration for 3 or 7 days to thyroidectomized rats did not reduce glycogen stores (7.75+/-1.02 and 9.62+/-1.16 mg/g of LV, respectively), whereas myocardial glycogen declined to 3.30+/-0.58 mg/g of LV after 10 days of treatment. During hypoxia, cardiac muscle from thyroidectomized rats maintained greater active force and developed less contracture relative to euthyroid and, to a greater extent, than hyperthyroid rats. Removal of glucose from the bath decreased anaerobic performance and impaired recovery; however, myocardium from thyroidectomized rats remained more tolerant to hypoxia than the euthyroid group. Overall, the intrinsic LV glycogen content was positively correlated to anaerobic performance. These data demonstrate that the thyroid state profoundly affects myocardial growth, contractility and anaerobic performance of rat myocardium. Although energy demand may affect function during hypoxia, anaerobic substrate reserve (cardiac glycogen concentration) appears to be the primary factor determining tolerance to hypoxic stress.

Topics: Animals; Cell Hypoxia; Disease Models, Animal; Glycogen; Heart; Heart Ventricles; Injections, Subcutaneous; Male; Myocardial Contraction; Myocardium; Organ Size; Papillary Muscles; Rats; Thyroidectomy; Triiodothyronine; Ventricular Myosins

Lafora progressive myoclonus epilepsy (Lafora disease; LD) is a fatal autosomal recessive neurodegenerative disorder caused by loss-of-function mutations in either the EPM2A gene, encoding the dual specificity phosphatase laforin, or the EPM2B gene, encoding the E3-ubiquitin ligase malin. Previously, we and others have shown that both proteins form a functional complex that regulates glycogen synthesis by a novel mechanism involving ubiquitination and proteasomal degradation of at least two proteins, glycogen synthase and R5/PTG. Since laforin and malin localized at the endoplasmic reticulum (ER) and their regulatory role likely extend to other proteins unrelated to glycogen metabolism, we postulated that their absence may also affect the ER-unfolded protein response pathway.. Here, we demonstrate that siRNA silencing of laforin in Hek293 and SH-SY5Y cells increases their sensitivity to agents triggering ER-stress, which correlates with impairment of the ubiquitin-proteasomal pathway and increased apoptosis. Consistent with these findings, analysis of tissue samples from a LD patient lacking laforin, and from a laforin knockout (Epm2a-/-) mouse model of LD, demonstrates constitutive high expression levels of ER-stress markers BIP/Grp78, CHOP and PDI, among others.. We demonstrate that, in addition to regulating glycogen synthesis, laforin and malin play a role protecting cells from ER-stress, likely contributing to the elimination of unfolded proteins. These data suggest that proteasomal dysfunction and ER-stress play an important role in the pathogenesis of LD, which may offer novel therapeutic approaches for this fatal neurodegenerative disorder.

Topics: Animals; Carrier Proteins; Cell Line, Tumor; Disease Models, Animal; Dual-Specificity Phosphatases; Endoplasmic Reticulum; Endoplasmic Reticulum Chaperone BiP; Glycogen; Humans; Lafora Disease; Mice; Mice, Inbred C57BL; Mice, Knockout; Phosphoric Monoester Hydrolases; Proteasome Endopeptidase Complex; Protein Tyrosine Phosphatases, Non-Receptor; Ubiquitin; Ubiquitin-Protein Ligases

Recent human studies reveal a widespread association between short sleep and obesity. Two hypotheses, which are not mutually exclusive, might explain this association. First, genetic factors that reduce endogenous sleep times might also impact energy stores, an assertion that we confirmed in a previous study. Second, metabolism may be altered by chronic partial sleep deprivation. Here we address the second assertion by measuring the impact of long-term partial sleep deprivation on energy stores using Drosophila as a model. We subjected flies to long-term partial sleep deprivation via two different methods: a mechanical stimulus and a light stimulus. We then measured whole-body triglycerides and glycogen, two important sources of energy for the fly, and compared them to un-stimulated controls. We also measured changes in energy stores in response to a random circadian clock shift. Sex and line-dependent alterations in glycogen and/or triglyceride levels occurred in response to the circadian clock shift and in flies subjected to a single night of sleep deprivation using light. Thus, consistent with previous studies, our findings suggest that acute sleep loss and changes to the circadian clock can alter metabolism. Significant changes in energy stores were also observed when flies were subjected to chronic sleep loss via the mechanical stimulus, although not the light stimulus. Interestingly, mechanical stimulation resulted in the same change in energy stores even when it was not associated with sleep deprivation, suggesting that the changes are caused by stress rather than sleep loss. These findings emphasize the importance of taking stress into account when evaluating the relationship between sleep loss and metabolism.

Topics: Animals; Circadian Rhythm; Disease Models, Animal; Drosophila melanogaster; Energy Metabolism; Female; Glycogen; Male; Sleep Deprivation; Triglycerides

Mutations in the gene for muscle phosphofructo-1-kinase (PFKM), a key regulatory enzyme of glycolysis, cause Type VII glycogen storage disease (GSDVII). Clinical manifestations of the disease span from the severe infantile form, leading to death during childhood, to the classical form, which presents mainly with exercise intolerance. PFKM deficiency is considered as a skeletal muscle glycogenosis, but the relative contribution of altered glucose metabolism in other tissues to the pathogenesis of the disease is not fully understood. To elucidate this issue, we have generated mice deficient for PFKM (Pfkm(-/-)). Here, we show that Pfkm(-/-) mice had high lethality around weaning and reduced lifespan, because of the metabolic alterations. In skeletal muscle, including respiratory muscles, the lack of PFK activity blocked glycolysis and resulted in considerable glycogen storage and low ATP content. Although erythrocytes of Pfkm(-/-) mice preserved 50% of PFK activity, they showed strong reduction of 2,3-biphosphoglycerate concentrations and hemolysis, which was associated with compensatory reticulocytosis and splenomegaly. As a consequence of these haematological alterations, and of reduced PFK activity in the heart, Pfkm(-/-) mice developed cardiac hypertrophy with age. Taken together, these alterations resulted in muscle hypoxia and hypervascularization, impaired oxidative metabolism, fiber necrosis, and exercise intolerance. These results indicate that, in GSDVII, marked alterations in muscle bioenergetics and erythrocyte metabolism interact to produce a complex systemic disorder. Therefore, GSDVII is not simply a muscle glycogenosis, and Pfkm(-/-) mice constitute a unique model of GSDVII which may be useful for the design and assessment of new therapies.

Topics: Animals; Cardiomegaly; Disease Models, Animal; Erythrocytes; Female; Glycogen; Glycogen Storage Disease Type VII; Hematologic Diseases; Humans; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Muscle, Skeletal; Phosphofructokinase-1

Persistent atrial fibrillation (AF) has been associated with structural and electric remodeling and reduced contractile function.. To unravel mechanisms underlying reduced sarcoplasmic reticulum (SR) Ca(2+) release in persistent AF.. We studied cell shortening, membrane currents, and [Ca(2+)](i) in right atrial myocytes isolated from sheep with persistent AF (duration 129+/-39 days, N=16), compared to matched control animals (N=21). T-tubule density, ryanodine receptor (RyR) distribution, and local [Ca(2+)](i) transients were examined in confocal imaging.. Myocyte shortening and underlying [Ca(2+)](i) transients were profoundly reduced in AF (by 54.8% and 62%, P<0.01). This reduced cell shortening could be corrected by increasing [Ca(2+)](i). SR Ca(2+) content was not different. Calculated fractional SR Ca(2+) release was reduced in AF (by 20.6%, P<0.05). Peak Ca(2+) current density was modestly decreased (by 23.9%, P<0.01). T-tubules were present in the control atrial myocytes at low density and strongly reduced in AF (by 45%, P<0.01), whereas the regular distribution of RyR was unchanged. Synchrony of SR Ca(2+) release in AF was significantly reduced with increased areas of delayed Ca(2+) release. Propagation between RyR was unaffected but Ca(2+) release at subsarcolemmal sites was reduced. Rate of Ca(2+) extrusion by Na(+)/Ca(2+) exchanger was increased.. In persistent AF, reduced SR Ca(2+) release despite preserved SR Ca(2+) content is a major factor in contractile dysfunction. Fewer Ca(2+) channel-RyR couplings and reduced efficiency of the coupling at subsarcolemmal sites, possibly related to increased Na(+)/Ca(2+) exchanger, underlie the reduction in Ca(2+) release.

Topics: Actin Cytoskeleton; Animals; Atrial Fibrillation; Atrial Function, Right; Calcium Channels, L-Type; Calcium Signaling; Disease Models, Animal; Electrophysiologic Techniques, Cardiac; Female; Glycogen; Heart Atria; Membrane Potentials; Myocardial Contraction; Myocytes, Cardiac; Ryanodine Receptor Calcium Release Channel; Sarcolemma; Sarcoplasmic Reticulum; Sheep; Sodium-Calcium Exchanger; Time Factors

Acute respiratory distress syndrome (ARDS) is the most severe form of acute lung injury (ALI). The aim of the present study was to investigate whether paraquat-induced acute pulmonary and extra-pulmonary lung injury (ALI-P and ALI-EX, respectively), in rats, affects glycogen content in different tissues. This measurement could indicate performance limitations of tissues, a new biochemical aspect of ARDS. ALI-P and ALI-EX were induced by injection into the trachea (0.5 mg/kg) and intraperitoneally (20 mg/kg) 24 hours prior to tissue collection. The control groups (CTRL) received the same volume of saline. Glycogen content (mg/g tissue) from different tissues was measured using the anthrone reagent. Glycogen content in the heart and kidney was higher in the ALI-EX group than the CTRL-EX group. Glycogen content in the gastrocnemius muscle was lower in the ALI-EX group than the CTRL-EX group. However, there were no significant differences in glycogen content in the diaphragm in the ALI-EX and ALI-P groups or in the gastrocnemius, heart and kidney in the ALI-P group when compared to the respective controls. ALI-EX caused a greater thickening of the alveolar walls, more areas of atelectasis and a greater abundance of inflammatory cells in comparison to ALI-P. These results demonstrate that glycogen content in ALI, induced by an herbicide that is highly toxic to humans and animals, is altered in different tissues depending on the location of the injury.

Topics: Acute Lung Injury; Animals; Diaphragm; Disease Models, Animal; Glycogen; Herbicides; Injections, Intraperitoneal; Kidney; Lung; Male; Muscle, Skeletal; Myocardium; Organ Specificity; Paraquat; Rats; Rats, Wistar; Respiratory Distress Syndrome

The goal of the study was to examine the state of primary hepatocytes of rats with toxic hepatitis induced by combination of CCl4 and ethanol. Fluorescent immunocytochemical analysis demonstrated that normal and pathologic hepatocytes in culture formed actin cytoskeleton, cell-cell and cell-matrix contacts. To investigate morphology and localization of mitochondria the hepatocytes were stained with Rhodamine 123. Glycogen and DNA contents in hepatocytes were determined by fluorescent cytophotometry during the lifetime of the culture. Cells were maintained for 5 days, and there were no changes in ploidy distribution observed. The mean ploidy was not changed too. Thus hepatocytes of different ploidy demonstrated similar survival rate. The glycogen content was 50% higher in experimental group compared to the control. The glycogen content decreased in control and cyrrotic hepatocytes after collagenase isolation. It has been found that the control hepatocytes accumulated glycogen within 3 days. On the contrary, the glycogen levels remained to be low in the pathologic hepatocytes.

Topics: Animals; Carbon Tetrachloride; Cells, Cultured; Chemical and Drug Induced Liver Injury, Chronic; Disease Models, Animal; Ethanol; Glycogen; Hepatocytes; Male; Mitochondria; Rats; Rats, Wistar

Humans with an R302Q mutation in AMPKgamma(2) (the PRKAG2 gene) develop a glycogen storage cardiomyopathy characterized by a familial form of Wolff-Parkinson-White syndrome and cardiac hypertrophy. This phenotype is recapitulated in transgenic mice with cardiomyocyte-restricted expression of AMPKgamma(2)R302Q. Although considerable information is known regarding the consequences of harboring the gamma(2)R302Q mutation, little is known about the early signaling events that contribute to the development of this cardiomyopathy.. To distinguish the direct effects of gamma(2)R302Q expression from later compensatory alterations in signaling, we used transgenic mice expressing either the wild-type AMPKgamma(2) subunit (TGgamma(2)WT) or the mutated form (TGgamma(2)R302Q), in combination with acute expression of these proteins in neonatal rat cardiomyocytes. Although acute expression of gamma(2)R302Q induces AMPK activation and upregulation of glycogen synthase and AS160, with an associated increase in glycogen content, AMPK activity, glycogen synthase activity, and AS160 expression are reduced in hearts from TGgamma(2)R302Q mice, likely in response to the existing 37-fold increase in glycogen. Interestingly, gamma(2)WT expression has similar, yet less marked effects than gamma(2)R302Q expression in both cardiomyocytes and hearts.. Using acute and chronic models of gamma(2)R302Q expression, we have differentiated the direct effects of the gamma(2)R302Q mutation from eventual compensatory modifications. Our data suggest that expression of gamma(2)R302Q induces AMPK activation and the eventual increase in glycogen content, a finding that is masked in hearts from transgenic adult mice. These findings are the first to highlight temporal differences in the effects of the PRKAG2 R302Q mutation on cardiac metabolic signaling events.

Topics: AMP-Activated Protein Kinases; Animals; Cells, Cultured; Disease Models, Animal; Female; Gene Expression; Glycogen; Humans; Male; Mice; Mice, Transgenic; Mutation, Missense; Myocytes, Cardiac; Rats; Signal Transduction; Wolff-Parkinson-White Syndrome

Pompe disease (glycogen storage disease II) is caused by mutations in the acid alpha-glucosidase gene. The most common form is rapidly progressive with glycogen storage, particularly in muscle, which leads to profound weakness, cardiac failure, and death by the age of 2 years. Although usually considered a muscle disease, glycogen storage also occurs in the CNS. We evaluated the progression of neuropathologic and behavioral abnormalities in a Pompe disease mouse model (6neo/6neo) that displays many features of the human disease. Homozygous mutant mice store excess glycogen within large neurons of hindbrain, spinal cord, and sensory ganglia by the age of 1 month; accumulations then spread progressively within many CNS cell types. "Silver degeneration" and Fluoro-Jade C stains revealed severe degeneration in axon terminals of primary sensory neurons at 3 to 9 months. These abnormalities were accompanied by progressive behavioral impairment on rotorod, wire hanging, and foot fault tests. The extensive neuropathologic alterations in this model suggest that therapy of skeletal and cardiac muscle disorders by systemic enzyme replacement therapy may not be sufficient to reverse functional deficits due to CNS glycogen storage, particularly early-onset, rapidly progressive disease. A better understanding of the basis for clinical manifestations is needed to correlate CNS pathology with Pompe disease manifestations.

Topics: Age Factors; alpha-Glucosidases; Animals; Behavior, Animal; Central Nervous System; Disease Models, Animal; Disease Progression; Glial Fibrillary Acidic Protein; Glycogen; Glycogen Storage Disease Type II; Mice; Mice, Inbred C57BL; Mice, Knockout; Microscopy, Electron, Transmission; Motor Activity; Muscle Strength; Muscle, Skeletal; Phenotype; Psychomotor Performance; Reaction Time

Here, we investigated the effect of jump exercise on tumor growth, cancer cachexia, lymphocyte proliferation and macrophage function in Walker 256 tumor-bearing rats. Male Wistar rats (60 days) were divided into sedentary (C) and exercised (E) groups. Jump training consisted of six sets of 10 jumps in water with overload of 50% of body mass with 1 min of resting, four times per week for 8 weeks. After 6 weeks of training, half of each group was inoculated with 2 x 10(7) cells of Walker 256 tumor. Sedentary tumor-bearing and exercised tumor-bearing are referred to as T and TE, respectively. Tumor weight in the T group was 25 g. These animals display loss of weight, hypertriacylglycerolemia, hyperlacticidemia, depletion of glycogen stores and increase in PIF expression. Jump exercise (TE) induced a significant lower tumor weight, preserves liver glycogen stores, partly prevented the hypertriacylglycerolemia, hyperlacticidemia and, prevented the fall in body weight and reduced PIF expression. Lymphocyte was increased by tumor burden (T) and was higher by including exercise (TE). The same was observed regarding phagocytosis and lysosomal volume. Anaerobic exercise decreases tumor growth, cancer cachexia and increases innate and adaptative immune function.

Topics: Animals; Body Weight; Cachexia; Carcinoma 256, Walker; Cell Proliferation; Disease Models, Animal; Glycogen; Lactates; Lymphocytes; Macrophages; Male; Phagocytosis; Physical Conditioning, Animal; Rats; Rats, Wistar; Triglycerides; Weight Loss

The present study was undertaken to determine the effect of Yi-Qi-Yang-Yin-Ye (Y-Q-Y-Y-Y), a compound of Traditional Chinese Herbal Medicine, on insulin resistance (IR) in the diet-induced obese rat model induced by intravenous injection with a low dose of streptozotocin and fed a high fat and high caloric diet. Y-Q-Y-Y-Y (2, 4, 8 g/kg) was administered via gavage daily for 4 weeks. The results showed that Y-Q-Y-Y-Y treatment decreased the levels of body weight, total cholesterol (TC), triglycerides (TG), low density lipoprotein-cholesterol (LDL-C), free fatty acid (FFA), insulin (INS) and fast blood glucose (FBG) and increased the level of high density lipoprotein-cholesterol (HDL-C) in the diet-induced obese rats. Glucose tolerance was improved in the diet-induced obese rats treated with Y-Q-Y-Y-Y as well as GIR (glucose infusion rate) in the hyperinsulinemic euglycemic clamp experiment compared to the model control rats (p < 0.01). Moreover, treatment with Y-Q-Y-Y-Y up-regulated glycogen contents in both liver and skeletal muscle and increased insulin receptor amounts on the erythrocytes surface as assessed by using (125)I-labeled auto-antibodies against insulin receptors. Taken together, our data suggested that Yi-Qi-Yang-Yin-Ye ameliorates insulin resistance in the diet-induced obese rats.

Topics: Animals; Blood Glucose; Body Weight; Disease Models, Animal; Drugs, Chinese Herbal; Energy Intake; Glycogen; Insulin; Insulin Resistance; Lipid Metabolism; Liver; Medicine, Chinese Traditional; Muscle, Skeletal; Obesity; Rats; Rats, Wistar; Receptor, Insulin

Effects in the liver of fatal intoxication with the binary toxin ricin are unclear. We report a robust neutrophil influx into the liver of C57BL/6 mice after lethal parenteral ricin challenge, occurring in peri-portal and centro-lobular hepatic areas within 2 h, followed by the abrupt disappearance of hepatic macrophages/Kupffer cells. Chemokine profiles determined by microarray, ribonuclease protection assays, northern blotting, and enzyme-linked immunosorbent assays showed rapid (2 h) upregulation and persistence of those for neutrophils (CXCL1/KC, CXCL2/MIP-2) and monocytes (CCL2/MCP-1). Red blood cell pooling (8-12 h), loss of hepatocyte glycogen (8-48 h) associated with progressive hypoglycemia, fibrin deposition (24-48 h), and death (72-96 h) followed. Monoclonal antibody to ricin A chain, administered intravenously, blunted hypoglycemia, and abrogated death. This outcome was observed when anti-ricin antibody was given before toxin exposure as well as when administered approximately 10 h after toxin exposure. Targeting antibody to specific amino-acid sequences on the ricin A chain (HAEL and QXXWXXA) was critical to the therapeutic effect. Re-emergence of liver macrophages/Kupffer cells and replenishment of glycogen in previously depleted hepatocytes preceded full recovery of the host. These data identify critical events for liver injury and healing in ricin intoxication, as well as a new means and specific targets for post-exposure therapeutic intervention.

Topics: Animals; Antibodies, Monoclonal; Antibody Specificity; Chemical Warfare Agents; Disease Models, Animal; Epitopes; Glycogen; Hepatocytes; Hypoglycemia; Kupffer Cells; Male; Mice; Oligonucleotide Array Sequence Analysis; Poisoning; Recovery of Function; Ricin

Neonatal respiratory distress syndrome (RDS) is mainly the result of perturbation in surfactant production and is a common complication seen in premature infants. Normal fetal lung development and alveolar cell differentiation is regulated by a network of transcription factors. Functional loss of any of these factors will alter the developmental program and impact surfactant production and normal gas exchange. During development, the fetus is exposed to varying oxygen concentrations and must be able to quickly adapt to these changes in order to survive. Hypoxia-inducible factor 1alpha (HIF1alpha) is the primary transcription factor that is responsible for regulating the cellular response to changes in oxygen tension and is essential for normal development. Its role in lung maturation is not well defined and to address this knowledge gap, a lung-specific HIF1alpha knock-out model has been developed. Loss of HIF1alpha early in lung development leads to pups that die within hours of parturition, exhibiting symptoms similar to RDS. Lungs from these pups display impaired alveolar epithelial differentiation and an almost complete loss of surfactant protein expression. Ultrastructural analysis of lungs from HIF1alpha deletion pups had high levels of glycogen, aberrant septal development, and decreased expression of several factors necessary for proper lung development, including HIF2alpha, beta-catenin, and vascular endothelial growth factor. These results suggest that HIF1alpha is essential for proper lung maturation and alteration in its normal signaling during premature delivery might explain the pathophysiology of neonatal RDS.

Topics: Adaptation, Physiological; Animals; Animals, Newborn; Cell Differentiation; Disease Models, Animal; Female; Fetal Development; Fetus; Gene Knockdown Techniques; Glycogen; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Infant, Newborn; Male; Mice; Mice, Transgenic; Oxygen; Pregnancy; Pulmonary Alveoli; Pulmonary Surfactant-Associated Proteins; Respiratory Distress Syndrome, Newborn; Respiratory Mucosa; Signal Transduction

Nitric oxide (NO) may limit myocardial ischemia-reperfusion injury by slowing the mitochondrial metabolism. We examined whether rat heart contains catalysts potentially capable of reducing nitrite to NO during an episode of regional myocardial ischemia produced by temporary coronary artery occlusion. In intact Sprague-Dawley rats, a 15-min coronary occlusion lowered the nitrite concentration of the myocardial regions exhibiting ischemic glucose metabolism to approximately 50% that of nonischemic regions (185 +/- 223 vs. 420 +/- 203 nmol/l). Nitrite was rapidly repleted during subsequent reperfusion. The heart tissue tested in vitro acquired a substantial ability to consume nitrite when made hypoxic at neutral pH, and this ability was slightly enhanced by simultaneously lowering the pH to 5.5. More than 70% of this activity could be abolished by flushing the coronary circulation with crystalloid to remove trapped erythrocytes. Correspondingly, erythrocytes demonstrated the ability to reduce exogenous nitrite to NO under hypoxic conditions in vitro. In erythrocyte-free heart tissue, the nitrite consumption increased fivefold when the pH was lowered to 5.5. Approximately 40% of this pH-sensitive increase in nitrite consumption could be blocked by the xanthine oxidoreductase inhibitor allopurinol, whereas lowering the Po(2) sufficiently to desaturate myoglobin accelerated it further. We conclude that rat heart contains several factors capable of catalyzing ischemic nitrite reduction; the most potent is contained within erythrocytes and activated by hypoxia, whereas the remainder includes xanthine oxidoreductase and other pH-sensitive factors endogenous to heart tissue, including deoxymyoglobin.

Topics: Allopurinol; Animals; Catalysis; Disease Models, Animal; Enzyme Inhibitors; Erythrocytes; Glucose; Glycogen; Hydrogen-Ion Concentration; Hypoxia; Male; Myocardial Ischemia; Myocardial Reperfusion Injury; Myocardium; Myoglobin; Nitric Oxide; Nitrites; Oxidation-Reduction; Rats; Rats, Sprague-Dawley; Time Factors; Xanthine Dehydrogenase

Lafora disease is a progressive myoclonus epilepsy with onset in the teenage years followed by neurodegeneration and death within 10 years. A characteristic is the widespread formation of poorly branched, insoluble glycogen-like polymers (polyglucosan) known as Lafora bodies, which accumulate in neurons, muscle, liver, and other tissues. Approximately half of the cases of Lafora disease result from mutations in the EPM2A gene, which encodes laforin, a member of the dual specificity protein phosphatase family that is able to release the small amount of covalent phosphate normally present in glycogen. In studies of Epm2a(-/-) mice that lack laforin, we observed a progressive change in the properties and structure of glycogen that paralleled the formation of Lafora bodies. At three months, glycogen metabolism remained essentially normal, even though the phosphorylation of glycogen has increased 4-fold and causes altered physical properties of the polysaccharide. By 9 months, the glycogen has overaccumulated by 3-fold, has become somewhat more phosphorylated, but, more notably, is now poorly branched, is insoluble in water, and has acquired an abnormal morphology visible by electron microscopy. These glycogen molecules have a tendency to aggregate and can be recovered in the pellet after low speed centrifugation of tissue extracts. The aggregation requires the phosphorylation of glycogen. The aggregrated glycogen sequesters glycogen synthase but not other glycogen metabolizing enzymes. We propose that laforin functions to suppress excessive glycogen phosphorylation and is an essential component of the metabolism of normally structured glycogen.

Topics: Animals; Disease Models, Animal; Dual-Specificity Phosphatases; Ethanol; Glycogen; Humans; Lafora Disease; Mice; Mice, Transgenic; Models, Biological; Models, Genetic; Phosphates; Polymers; Protein Tyrosine Phosphatases, Non-Receptor; Time Factors

The brain is heavily dependant on glucose for its function and survival. Hypoglycemia can have severe, irreversible consequences, including seizures, coma and death. However, the in vivo content of brain glycogen, the storage form of glucose, is meager and is a function of both neuronal activity and glucose concentration. In the intact in vitro hippocampus isolated from mice aged postnatal days 8-13, we have recently characterized a novel model of hypoglycemic seizures, wherein seizures were abolished by various neuroprotective strategies. We had hypothesized that these strategies might act, in part, by increasing cerebral glycogen content. In the present experiments, it was found that neither decreasing temperature nor increasing glucose concentrations (above 2 mM) significantly increased hippocampal glycogen content. Preparations of isolated frontal neocortex in vitro do not produce hypoglycemic seizures yet it was found they contained significantly lower glycogen content as compared to the isolated intact hippocampus. Further, the application of either TTX, or a cocktail containing APV, CNQX and gabazine, to block synaptic activity, did not increase, but paradoxically decreased, hippocampal glycogen content in the isolated intact hippocampus. Significant decreases in glycogen were noted when neuronal activity was increased via incubation with l-aspartate (500 muM) or low Mg(2+). Lastly, we examined the incidence of hypoglycemic seizures in hippocampi isolated from mice aged 15-19 and 22-24 days, and compared it to the incidence of hypoglycemic seizures of hippocampi isolated from mice aged 8-13 days described previously (Abdelmalik et al., 2007 Neurobiol Dis 26(3):646-660). It was noted that hypoglycemic seizures were generated less frequently, and had less impact on synaptic transmission in hippocmpi from PD 22-24 as compared to hippocampi from mice PD 15-19 or PD 8-13. However, hippocampi from 8- to 13-day-old mice had significantly more glycogen than the other two age groups. The present data suggest that none of the interventions which abolish hypoglycemic seizures increases glycogen content, and that low glycogen content, per se, may not predispose to the generation of hypoglycemic seizures.

Topics: Age Factors; Analysis of Variance; Anesthetics, Local; Animals; Animals, Newborn; Aspartic Acid; Cerebellum; Disease Models, Animal; Drug Combinations; Excitatory Amino Acid Antagonists; Glucose; Glycogen; Hippocampus; Hypoglycemia; In Vitro Techniques; Male; Mice; Mice, Inbred C57BL; Seizures; Synaptic Transmission; Tetrodotoxin

The healing activity of malabaricone B and malabaricone C, the major antioxidant constituents of the spice Myristica malabarica against the indomethacin-induced gastric ulceration in mice has been studied. The histological indices revealed maximum ulceration on the 3rd day after indomethacin administration, which was effectively healed by malabaricone B, malabaricone C (each 10 mg/kg body weight/day) and omeprazole (3 mg/kg body weight/day) for 3 days. Compared to the untreated ulcerated mice, treatment with malabaricone B, malabaricone C and omeprazole reduced the ulcer indices by 60.3% (P<0.01), 88.4% and 86.1% respectively (P<0.001). All the test samples accelerated ulcer healing than observed in natural recovery even after 7 days. Stomach ulceration reduced the total antioxidant status of plasma by 41% (P<0.05), which was significantly increased by malabaricone B (36%, P<0.01), malabaricone C (61%, P<0.001) and omeprazole (53%, P<0.001). Compared to the ulcerated untreated mice, those treated with malabaricone B reduced the levels of thiobarbituric acid reactive substances and protein carbonyls by 17% and approximately 34% respectively (P<0.05), while malabaricone C and omeprazole reduced the parameters almost equally (approximately 30%, P<0.01, and approximately 40%, P<0.01 respectively). Likewise, all the test samples reduced the oxidation of protein and non-protein thiols significantly (P<0.05). The antioxidant activity of the test samples could partly account their healing capacities. However, the differential potency of them was explainable by considering their relative abilities to modulate mucin secretion, PGE(2) synthesis and expression of EGF receptor and COX isoforms, malabaricone C being most effective in controlling all these factors.

Topics: Animals; Anti-Ulcer Agents; Antioxidants; Cyclooxygenase 1; Cyclooxygenase 2; Dinoprostone; Disease Models, Animal; Dose-Response Relationship, Drug; ErbB Receptors; Fruit; Gastric Mucins; Gastric Mucosa; Glycogen; Indomethacin; Lipid Peroxidation; Male; Membrane Proteins; Mice; Myristicaceae; Omeprazole; Oxidative Stress; Periodic Acid-Schiff Reaction; Plant Extracts; Protein Carbonylation; Resorcinols; Stomach; Stomach Ulcer; Time Factors; Wound Healing

A dual-tracer approach (dietary 14C-palmitate and intraperitoneal 3H-H2O) was used to assess the trafficking of dietary fat and net retention of carbon in triglyceride depots during the first 24 h of weight regain. Obesity-prone male Wistar rats were allowed to mature under obesogenic conditions for 16 wk. One group was switched to ad libitum feeding of a low-fat diet for 10 wk (Obese group). The remaining rats were switched to an energy-restricted, low-fat diet for 10 wk that reduced body weight by 14% and were then assessed in energy balance (Reduced group), with free access to the low-fat diet (Relapse-Day1 group), or with a provision that induced a minor imbalance (+10 kcal) equivalent to that observed in obese rats (Gap-Matched group). Fat oxidation remained at a high, steady rate throughout the day in Obese rats, but was suppressed in Reduced, Gap-Matched, and Relapse-Day1 rats though 9, 18, and 24 h, respectively. The same caloric excess in Obese and Gap-Matched rats led to less fat oxidation over the day and greater trafficking of dietary fat to visceral depots in the latter. In addition to trafficking nutrients to storage, Relapse-Day1 rats had more small, presumably new, adipocytes at the end of 24 h. Dietary fat oxidation at 24 h was related to the phosphorylation of skeletal muscle acetyl-CoA carboxylase and fatty acid availability. These observations provide evidence of adaptations in the oxidation and trafficking of dietary fat that extend beyond the energy imbalance, which facilitate rapid, efficient regain during the relapse to obesity.

Topics: Acetyl-CoA Carboxylase; Adaptation, Physiological; Adipocytes; Animals; Body Composition; Cell Proliferation; Diet, Fat-Restricted; Dietary Fats; Disease Models, Animal; Down-Regulation; Energy Intake; Energy Metabolism; Fatty Acids; Glycogen; Hyperplasia; Intra-Abdominal Fat; Male; Muscle, Skeletal; Obesity; Oxidation-Reduction; Phosphorylation; Rats; Rats, Wistar; Recurrence; Time Factors; Triglycerides; Weight Gain; Weight Loss

A stimulatory effect of kaempferol 3-neohesperidoside ( 1) on glucose uptake (35% and 21%) was observed when the rat soleus muscle was incubated with 1 and 100 nM of this flavonoid glycoside, respectively. The concentration-response curve of insulin showed a stimulatory effect at 3.5 and 7.0 nM (42% and 50%) on glucose uptake when compared with the control group. The effect of 1 on glucose uptake was completely nullified by pretreatment with LY294002, an inhibitor of phosphoinositide 3-kinase (PI3K), and RO318220, an inhibitor of protein kinase C (PKC). However, no significant change occurred on glucose uptake stimulated by 1 when muscles were pretreated with PD98059, an inhibitor of mitogen-activated protein kinase (MEK), and cycloheximide, an inhibitor of protein synthesis. Compound 1 and insulin (7 nM) did not show a synergistic effect on glucose uptake. Additionally, 100 mg/kg of 1 by oral gavage was able to increase glycogen content in the muscle. These results suggest that 1 stimulates glucose uptake in the rat soleus muscle via the PI3K and PKC pathways and, at least in part, independently of MEK pathways and the synthesis of new glucose transporters.

Topics: Alloxan; Animals; Blood Glucose; Diabetes Mellitus, Experimental; Disease Models, Animal; Ferns; Glycogen; Insulin; Kaempferols; Molecular Structure; Muscle, Skeletal; Plants, Medicinal; Rats

The toxic effects of Asian black scorpion Heterometrus fastigiousus (Family, Scorpionidae) venom were determined in albino mice (NIH strain). Venom was isolated and fractioned by Sepharose CL-6B column chromatography. The toxicity of fractioned venom was determined in albino mice by subcutaneous envenomation. The LD(50) of venom was found to be 15 mg kg(-1) body weight and range of molecular weight of venom proteins responsible for toxicity was found from 9.5-63 kDs. The effects of fractioned venom on different biochemical and enzymatic parameters in blood serum and gastrocnemius muscle tissue of albino mice were determined after experimental envenomation. An increase in serum levels of glucose, free amino acids, uric acid, pyruvic acid and total protein was observed while a decrease in the cholesterol level in serum was observed after 4 h of envenomation. Increase in alkaline phosphatase (ALP), acid phosphatase (ACP), lactic dehydrogenase (LDH) and glutamate-pyruvate transaminase (GPT) enzyme activity in serum was observed. Glycogen content in liver, atria, ventricle, rectus abdominus and gastrocnemius muscle was decreased after experimental envenomation. Activity of ALP, ACP, LDH, GPT, AChE and Na+K+ATPase enzymes in gastrocnemius muscle tissue of envenomed albino mice was studied. Inhibition in ALP, AChE and Na+K+ATPase enzyme activity and increase in ACP, LDH and GPT enzyme activity was observed in gastrocnemius muscle after scorpion envenomation. In vitro studies with AChE and Na+K+ATPase enzymes indicated that enzymatic activity of AChE was inhibited competitively by fractioned venom in gastrocnemius muscle.

Topics: Animals; Biomarkers; Bites and Stings; Chemical Fractionation; Clinical Chemistry Tests; Disease Models, Animal; Enzyme Inhibitors; Enzymes; Glycogen; Mice; Mice, Inbred Strains; Muscle, Skeletal; Scorpion Venoms; Scorpions

Medium-chain acyl-coenzyme A (CoA) dehydrogenase (MCAD) catalyzes crucial steps in mitochondrial fatty acid oxidation, a process that is of key relevance for maintenance of energy homeostasis, especially during high metabolic demand. To gain insight into the metabolic consequences of MCAD deficiency under these conditions, we compared hepatic carbohydrate metabolism in vivo in wild-type and MCAD(-/-) mice during fasting and during a lipopolysaccharide (LPS)-induced acute phase response (APR). MCAD(-/-) mice did not become more hypoglycemic on fasting or during the APR than wild-type mice did. Nevertheless, microarray analyses revealed increased hepatic peroxisome proliferator-activated receptor gamma coactivator-1alpha (Pgc-1alpha) and decreased peroxisome proliferator-activated receptor alpha (Ppar alpha) and pyruvate dehydrogenase kinase 4 (Pdk4) expression in MCAD(-/-) mice in both conditions, suggesting altered control of hepatic glucose metabolism. Quantitative flux measurements revealed that the de novo synthesis of glucose-6-phosphate (G6P) was not affected on fasting in MCAD(-/-) mice. During the APR, however, this flux was significantly decreased (-20%) in MCAD(-/-) mice compared with wild-type mice. Remarkably, newly formed G6P was preferentially directed toward glycogen in MCAD(-/-) mice under both conditions. Together with diminished de novo synthesis of G6P, this led to a decreased hepatic glucose output during the APR in MCAD(-/-) mice; de novo synthesis of G6P and hepatic glucose output were maintained in wild-type mice under both conditions. APR-associated hypoglycemia, which was observed in wild-type mice as well as MCAD(-/-) mice, was mainly due to enhanced peripheral glucose uptake.. Our data demonstrate that MCAD deficiency in mice leads to specific changes in hepatic carbohydrate management on exposure to metabolic stress. This deficiency, however, does not lead to reduced de novo synthesis of G6P during fasting alone, which may be due to the existence of compensatory mechanisms or limited rate control of MCAD in murine mitochondrial fatty acid oxidation.

Topics: Acyl-CoA Dehydrogenase; Animals; Blood Glucose; Carbohydrate Metabolism; Disease Models, Animal; Energy Metabolism; Fatty Acids; Gene Expression Regulation, Enzymologic; Glucose-6-Phosphate; Glycogen; Hypoglycemia; Lipopolysaccharides; Liver; Liver Diseases; Male; Mice; Mice, Knockout; Mitochondria, Liver

Cancer cachexia affects intermediary metabolism with intense and general catabolism. Walker 256 tumor is a model injected either subcutaneously (Sc) or intraperitoneally (Ip), with different metabolic features. Beta-hydroxy beta-methylbutyrate (HMbeta) is a leucine metabolite with anti-catabolic properties, the aim of this study being to investigate its effects on metabolic parameters in both tumor models.. Controls (subcutaneous control group (ScC) and intraperitoneal control group (IpC)) and supplemented animals (subcutaneous supplemented group (ScS) and intraperitoneal supplemented group (IpS)) showed these results.. Protein Sc values were (47.8%) lower than Ip groups. Sc group fat content was (65.16%) higher than Ip groups. Liver glycogen value for Sc groups was (38.4%) higher than Ip groups. Muscle glycogen value for Sc groups were (2.75 times) higher than Ip groups. Corticosterone and insulin values were lower (44.53%) and higher (45.94%), respectively, in Sc when compared with Ip groups. Glucose and lactate values for ScS were the lowest (61.7% and 41.53%) compared to other groups. ScC glutamine value was the highest (40.8%) of all groups. Glutamate Sc values were (42.65%) lower than Ip groups. Sc groups showed greater survival time compared with Ip groups. ScS group showed 100% increase in survival time when compared with ScC.. HMbeta supplementation can increase survival time and promotes metabolic changes in cancer-bearing animals, but it seems to work in a time-dependent manner.

Topics: 3-Hydroxybutyric Acid; Adipose Tissue; Animals; Body Composition; Cachexia; Carcinoma 256, Walker; Dietary Supplements; Disease Models, Animal; Energy Metabolism; Glycogen; Injections, Intraperitoneal; Injections, Subcutaneous; Liver Glycogen; Male; Proteins; Rats; Rats, Wistar; Survival Rate; Time Factors

Recent studies have identified the involvement of inhibitor IkappaB kinase (IKK) in the pathogenesis of insulin resistance. To investigate the mechanism involved, we examined the role of nuclear factor kappaB (NF-kappaB), the distal target of IKK, in hepatic glucose metabolism.. To inhibit NF-kappaB activity, db/db mice were infected with adenovirus expressing the IkappaBalpha super-repressor.. The IkappaBalpha super-repressor adenovirus infection caused a moderate reduction of NF-kappaB activity in liver. The treatment was associated with improved glucose tolerance, reduction in the serum insulin level, and increased hepatic triacylglycerol and glycogen contents, but had no effect on insulin-stimulated phosphorylation of Akt. On the other hand, quantification of mRNA in the liver revealed marked reduction of expression of gluconeogenic genes, such as those encoding phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase, concurrent with reduced expression of gene encoding peroxisome proliferator-activated receptor gamma coactivator-1alpha (PPARGC1A, also known as PGC-1alpha). Furthermore, the production of super-repressor IkappaBalpha suppressed the increase in blood glucose level after pyruvate injection.. Our results indicate that moderate inhibition of NF-kappaB improved glucose tolerance through decreased gluconeogenesis associated with reduced PGC-1alpha gene expression in db/db mice, and suggest that inhibition of NF-kappaB activity in liver is a potentially suitable strategy for the normalisation of blood glucose concentration in type 2 diabetes.

Topics: Adenoviridae; AMP-Activated Protein Kinases; Animals; Cyclic AMP Response Element-Binding Protein; Diabetes Mellitus; Disease Models, Animal; Female; Glucose; Glycogen; I-kappa B Proteins; Insulin Resistance; Liver; Mice; Mice, Inbred C57BL; Multienzyme Complexes; NF-kappa B; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; Protein Serine-Threonine Kinases; STAT3 Transcription Factor; Trans-Activators; Transcription Factors; Triglycerides

Laforin, encoded by the EPM2A gene, by sequence is a member of the dual specificity protein phosphatase family. Mutations in the EPM2A gene account for around half of the cases of Lafora disease, an autosomal recessive neurodegenerative disorder, characterized by progressive myoclonus epilepsy. The hallmark of the disease is the presence of Lafora bodies, which contain polyglucosan, a poorly branched form of glycogen, in neurons, muscle and other tissues. Glycogen metabolizing enzymes were analyzed in a transgenic mouse over-expressing a dominant negative form of laforin that accumulates Lafora bodies in several tissues. Skeletal muscle glycogen was increased 2-fold as was the total glycogen synthase protein. However, the -/+glucose-6-P activity of glycogen synthase was decreased from 0.29 to 0.16. Branching enzyme activity was increased by 30%. Glycogen phosphorylase activity was unchanged. In whole brain, no differences in glycogen synthase or branching enzyme activities were found. Although there were significant differences in enzyme activities in muscle, the results do not support the hypothesis that Lafora body formation is caused by a major change in the balance between glycogen elongation and branching activities.

Topics: Animals; Brain; Disease Models, Animal; Dual-Specificity Phosphatases; Glycogen; Glycogen Phosphorylase; Glycogen Synthase; Lafora Disease; Mice; Mice, Transgenic; Muscle, Skeletal; Protein Tyrosine Phosphatases; Protein Tyrosine Phosphatases, Non-Receptor

Altered metabolic responses of the newborn heart to ischemia, which may increase irreversible injury, may at least partially explain the greater morbidity and mortality experienced by some children undergoing congenital cardiac repair. The present study compared newborn heart metabolic responses to global ischemia with those of adult, and evaluated whether continuous coronary artery washout in the newborn heart during 'ischemia' could favourably affect these responses.. Adult (n=12) and newborn (n=12) pigs were anesthetized, and right ventricular biopsies were taken before global ischemia and at set intervals during ischemia. Another 12 newborns were subdivided into groups of nonperfused hearts and hearts receiving continuous perfusion. Time to onset of and time to peak of ischemic contracture were recorded. Biopsies were assayed for lactate, myocardial glycogen, glucose-6-phosphate and ATP.. Newborn hearts were more sensitive to global ischemia than adult hearts, based on shorter time to onset of and time to peak of ischemic contracture, and had a significantly greater rate of ATP decline (P<0.01). This was due in part to a more rapid accumulation of lactate (P<0.05) and only a 50% use of glycogen, compared with 93% by adult hearts. Continuous washout of newborn hearts prevented lactate accumulation, allowing a 90% use of glycogen and delaying time to ischemic contracture by twofold. This was accompanied by lower levels of glucose-6-phosphate accumulation (P<0.05) and a threefold reduction in the rate of ATP decline.. Significant differences in myocardial metabolism during ischemia in newborns compared with adults could predispose them to earlier ischemic injury, which can be eliminated by the removal of end products. Perfusion strategies taking these differences into account may further optimize pediatric myocardial protection and improve outcomes in newborn children undergoing cardiac procedures.

Topics: Adenosine Triphosphate; Age Factors; Analysis of Variance; Animals; Animals, Newborn; Coronary Circulation; Coronary Vessels; Disease Models, Animal; Glucose-6-Phosphate; Glycogen; Heart Ventricles; Ischemic Preconditioning, Myocardial; Lactates; Myocardial Reperfusion; Myocardial Reperfusion Injury; Myocardium; Swine; Time Factors

AMP-activated protein kinase (AMPK) responds to impaired cellular energy status by stimulating substrate metabolism for ATP generation. Mutation of the gamma2 regulatory subunit of AMPK in humans renders the kinase insensitive to energy status and causes glycogen storage cardiomyopathy via unknown mechanisms. Using transgenic mice expressing one of the mutant gamma2 subunits (N488I) in the heart, we found that aberrant high activity of AMPK in the absence of energy deficit caused extensive remodeling of the substrate metabolism pathways to accommodate increases in both glucose uptake and fatty acid oxidation in the hearts of gamma2 mutant mice via distinct, yet synergistic mechanisms resulting in selective fuel storage as glycogen. Increased glucose entry in the gamma2 mutant mouse hearts was directed through the remodeled metabolic network toward glycogen synthesis and, at a substantially higher glycogen level, recycled through the glycogen pool to enter glycolysis. Thus, the metabolic consequences of chronic activation of AMPK in the absence of energy deficiency is distinct from those previously reported during stress conditions. These findings are of particular importance in considering AMPK as a target for the treatment of metabolic diseases.

Topics: Amino Acid Substitution; AMP-Activated Protein Kinases; Animals; Cardiomyopathies; Disease Models, Animal; Energy Metabolism; Enzyme Activation; Glycogen; Glycogen Storage Disease; Humans; Mice; Multienzyme Complexes; Myocardium; Oxidative Stress; Protein Serine-Threonine Kinases; Substrate Cycling; Up-Regulation

Severe hypoglycemia constitutes a medical emergency, involving seizures, coma and death. We hypothesized that seizures, during limited substrate availability, aggravate hypoglycemia-induced brain damage. Using immature isolated, intact hippocampi and frontal neocortical blocks subjected to low glucose perfusion, we characterized hypoglycemic (neuroglycopenic) seizures in vitro during transient hypoglycemia and their effects on synaptic transmission and glycogen content. Hippocampal hypoglycemic seizures were always followed by an irreversible reduction (>60% loss) in synaptic transmission and were occasionally accompanied by spreading depression-like events. Hypoglycemic seizures occurred more frequently with decreasing "hypoglycemic" extracellular glucose concentrations. In contrast, no hypoglycemic seizures were generated in the neocortex during transient hypoglycemia, and the reduction of synaptic transmission was reversible (<60% loss). Hypoglycemic seizures in the hippocampus were abolished by NMDA and non-NMDA antagonists. The anticonvulsant, midazolam, but neither phenytoin nor valproate, also abolished hypoglycemic seizures. Non-glycolytic, oxidative substrates attenuated, but did not abolish, hypoglycemic seizure activity and were unable to support synaptic transmission, even in the presence of the adenosine (A1) antagonist, DPCPX. Complete prevention of hypoglycemic seizures always led to the maintenance of synaptic transmission. A quantitative glycogen assay demonstrated that hypoglycemic seizures, in vitro, during hypoglycemia deplete hippocampal glycogen. These data suggest that suppressing seizures during hypoglycemia may decrease subsequent neuronal damage and dysfunction.

Topics: Action Potentials; Adenosine A1 Receptor Antagonists; Animals; Anticonvulsants; Cortical Spreading Depression; Disease Models, Animal; Excitatory Amino Acid Antagonists; Glucose; Glycogen; Hippocampus; Hypoglycemia; Male; Mice; Mice, Inbred C57BL; Midazolam; Nerve Degeneration; Neurons; Receptor, Adenosine A1; Seizures; Synaptic Transmission

p38 mitogen-activated protein kinase (MAPK) and 5'-AMP-activated protein kinase (AMPK) are activated by metabolic stresses and are implicated in the regulation of glucose utilization and ischemia-reperfusion (IR) injury. This study tested the hypothesis that inhibition of p38 MAPK restores the cardioprotective effects of adenosine in stressed hearts by preventing activation of AMPK and the uncoupling of glycolysis from glucose oxidation. Working rat hearts were perfused with Krebs solution (1.2 mM palmitate, 11 mM [(3)H/(14)C]glucose, and 100 mU/l insulin). Hearts were stressed by transient antecedent IR (2 x 10 min I/5 min R) before severe IR (30 min I/30 min R). Hearts were treated with vehicle, p38 MAPK inhibitor (SB-202190, 10 microM), adenosine (500 microM), or their combination before severe IR. After severe IR, the phosphorylation (arbitrary density units) of p38 MAPK and AMPK, rates of glucose metabolism (micromol x g dry wt(-1) x min(-1)), and recovery of left ventricular (LV) work (Joules) were similar in vehicle-, SB-202190- and adenosine-treated hearts. Treatment with SB-202190 + adenosine versus adenosine alone decreased p38 MAPK (0.03 +/- 0.01, n = 3 vs. 0.48 +/- 0.10, n = 3, P < 0.05) and AMPK (0.00 +/- 0.00, n = 3 vs. 0.26 +/- 0.08, n = 3 P < 0.05) phosphorylation. This was accompanied by attenuated rates of glycolysis (1.51 +/- 0.40, n = 7 vs. 3.95 +/- 0.65, n = 7, P < 0.05) and H(+) production (2.12 +/- 0.76, n = 7 vs. 6.96 +/- 1.48, n = 7, P < 0.05), and increased glycogen synthesis (1.91 +/- 0.25, n = 6 vs. 0.27 +/- 0.28, n = 6, P < 0.05) and improved recovery of LV work (0.81 +/- 0.08, n = 7 vs. 0.30 +/- 0.15, n = 8, P < 0.05). These data indicate that inhibition of p38 MAPK abolishes subsequent phosphorylation of AMPK and improves the coupling of glucose metabolism, thereby restoring adenosine-induced cardioprotection.

Topics: Adenosine; AMP-Activated Protein Kinases; Animals; Cardiotonic Agents; Disease Models, Animal; Glucose; Glycogen; Glycolysis; Hydrogen-Ion Concentration; Imidazoles; In Vitro Techniques; Male; Multienzyme Complexes; Myocardial Ischemia; Myocardial Reperfusion Injury; Myocardium; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Protein Kinase Inhibitors; Protein Serine-Threonine Kinases; Pyridines; Rats; Rats, Sprague-Dawley; Severity of Illness Index; Ventricular Function, Left

Pompe disease (glycogenosis type II) is a rare lysosomal disorder caused by a mutational deficiency of acid alpha-glucosidase (GAA). This deficiency leads to glycogen accumulation in multiple tissues: heart, skeletal muscles, and the central nervous system. A knockout mouse model mimicking the human condition has been used for histological evaluation. Currently, the best method for preserving glycogen in Pompe samples uses epon-araldite resin. Although the preservation by this method is excellent, the size of the tissue is limited to 1 mm(3). To accurately evaluate brain pathology in the Pompe mouse model, a modified glycol methacrylate (JB-4 Plus) method was developed. This approach allowed the production of larger tissue sections encompassing an entire mouse hemisphere (8 x 15 mm) while also providing a high level of morphological detail and preservation of glycogen. Application of the JB-4 Plus method is appropriate when a high level of cellular detail is desired. A modified paraffin method was also developed for use when rapid processing of multiple samples is a priority. Traditional paraffin processing results in glycogen loss. The modified paraffin method with periodic acid postfixation resulted in improved tissue morphology and glycogen preservation. Both techniques provide accurate anatomic evaluation of the glycogen distribution in Pompe mouse brain.

Topics: Animals; Brain; Buffers; Cerebellum; Disease Models, Animal; Fixatives; Formaldehyde; Glycogen; Glycogen Storage Disease Type II; Mice; Mice, Inbred C57BL; Mice, Knockout; Paraffin Embedding; Periodic Acid; Tissue Fixation

Hypersecretion of glucagon contributes to abnormally increased hepatic glucose output in type 2 diabetes. Somatostatin (SST) inhibits murine glucagon secretion from isolated pancreatic islets via somatostatin receptor subtype-2 (sst2). Here, we characterize the role of sst2 in controlling glucose homeostasis in mice with diet-induced obesity. Sst2-deficient (sst2(-/-)) and control mice were fed high-fat diet for 14 wk, and the parameters of glucose homeostasis were monitored. Hepatic glycogen and lipid contents were quantified enzymatically and visualized histomorphologically. Enzymes regulating glycogen and lipid synthesis and breakdown were measured by real-time PCR and/or Western blot. Gluconeogenesis and glycogenolysis were determined from isolated primary hepatocytes and glucagon or insulin secretion from isolated pancreatic islets. Nonfasting glucose, glucagon, and fasting nonesterified fatty acids of sst2(-/-) mice were increased. Inhibition of glucagon secretion from sst2-deficient pancreatic islets by glucose or somatostatin was impaired. Insulin less potently reduced blood glucose concentration in sst2-deficient mice as compared with wild-type mice. Sst2-deficient mice had decreased nonfasting hepatic glycogen and lipid content. The activity/expression of enzymes controlling hepatic glycogen synthesis of sst2(-/-) mice was decreased, whereas enzymes facilitating glycogenolysis and lipolysis were increased. Somatostatin and an sst2-selective agonist decreased glucagon-induced glycogenolysis, without influencing de novo glucose production using cultured primary hepatocytes. This study demonstrates that ablation of sst2 leads to hyperglucagonemia. Increased glucagon concentration is associated with impaired glucose control in sst2(-/-) mice, resulting from decreased hepatic glucose storage, increased glycogen breakdown, and reduced lipid accumulation. Sst2 may constitute a therapeutic target to lower hyperglucagonemia in type 2 diabetes.

Topics: Animal Feed; Animals; Blood Glucose; Diabetes Mellitus, Type 2; Disease Models, Animal; Fasting; Fatty Acids, Nonesterified; Female; Glucagon; Gluconeogenesis; Glycogen; Glycogen Synthase; Glycogenolysis; Homeostasis; Hyperglycemia; Liver; Male; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Mice, Obese; Obesity; Receptors, Somatostatin; Triglycerides

To assess the relationship between glycogen content in bladder detrusor tissue and historical bladder function in a guinea-pig model of partial bladder outlet obstruction (PBOO).. In male immature guinea pigs PBOO was created with a silver ring around the proximal urethra; a control group had a sham operation for comparison. Longitudinal individual urodynamic data were obtained weekly, so that guinea pigs were killed at different levels of bladder dysfunction. Bladder sections were stained with periodic acid-Schiff (PAS) to assess overall morphology and glycogen granule density, scored from 0 (no glycogen) to 3. Glycogen scores were related to both the end-stage and historical extremes of bladder function values.. Glycogen granules were seen only in the detrusor; as their number increased their location expanded from only close to the serosa (glycogen score 1), through the detrusor (score 2) up to the urothelium (score 3). A glycogen score of 0 correlated with normal values for all urodynamic variables. Compared with a glycogen score of 0 a score of 1 correlated with significant (P < 0.05) changes in end-stage compliance (decrease) and contractility (increase) and significantly higher historical values for contractility, pressure and number of unstable contractions (NUC). In the group with a glycogen score of 2 there were significant changes in both the end-stage values and historical extremes for compliance, pressure, contractility and NUC (all P < 0.05). In the group with a glycogen score of 3 all these changes were even more dramatic, except for the end-stage contractility, for which the increase was not significant. From glycogen score 0 to score 3 all changes increased in magnitude.. A high glycogen content reflects a history of abnormal urodynamic function. This finding exemplifies the added value of structural analysis to urodynamic studies. Further studies are needed to relate bladder structure to the potential for functional recovery.

Topics: Animals; Disease Models, Animal; Glycogen; Guinea Pigs; Male; Urethral Obstruction; Urinary Bladder Neck Obstruction; Urodynamics

1. The efficacy of coumarin (1,2-benzopyrone) was examined for the regulation of hyperthyroidism in female rats. 2. Coumarin was administered (10 mg/kg per day for 15 days) to l-thyroxine (L-T(4))-induced hyperthyroid as well as to euthyroid rats and changes in serum concentrations of thyroid hormones and in associated parameters, such as serum cholesterol, activity of hepatic 5'-monodeiodinase (5'DI) and glucose-6-phosphatase (G-6-Pase), glycogen content, bodyweight and daily food consumption, were analysed. Simultaneously, changes in hepatic lipid peroxidation (LPO), reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) were also investigated. 3. Although L-T(4) administration increased serum levels of thyroid hormones, the activity of hepatic 5'DI, G-6-Pase and LPO and daily food consumption, it decreased the level of serum cholesterol, hepatic glycogen content and the activities of anti-oxidant enzymes, such as SOD, CAT and GSH. 4. However, simultaneous administration of coumarin for 15 days to a group of hyperthyroid animals reversed most of the aforementioned changes, indicating its potential to ameliorate hyperthyroidism. Moreover, the drug did not increase, but rather decreased, hepatic LPO, suggesting its safe nature. 5. The present findings reveal a positive role for coumarin in the regulation of hyperthyroidism without any hepatotoxicity. It also appears that the test compound inhibits thyroid function at both a glandular level and at the level of peripheral conversion of T(4) to tri-iodothyronine.

Topics: Animals; Antithyroid Agents; Body Weight; Catalase; Cholesterol; Coumarins; Disease Models, Animal; Eating; Female; Glucose-6-Phosphatase; Glutathione; Glycogen; Hyperthyroidism; Iodide Peroxidase; Lipid Peroxidation; Liver; Rats; Rats, Wistar; Superoxide Dismutase; Thyroid Gland; Thyroid Hormones; Thyroxine; Time Factors

Glycine N-methyltransferase (GNMT) affects genetic stability by regulating DNA methylation and interacting with environmental carcinogens. To establish a Gnmt knockout mouse model, 2 lambda phage clones containing a mouse Gnmt genome were isolated. At 11 weeks of age, the Gnmt-/- mice had hepatomegaly, hypermethioninemia, and significantly higher levels of both serum alanine aminotransferase and hepatic S-adenosylmethionine. Such phenotypes mimic patients with congenital GNMT deficiencies. A real-time polymerase chain reaction analysis of 10 genes in the one-carbon metabolism pathway revealed that 5,10-methylenetetrahydrofolate reductase, S-adenosylhomocysteine hydrolase (Ahcy), and formiminotransferase cyclodeaminase (Ftcd) were significantly down-regulated in Gnmt-/- mice. This report demonstrates that GNMT regulates the expression of both Ftcd and Ahcy genes. Results from pathological examinations indicated that 57.1% (8 of 14) of the Gnmt-/- mice had glycogen storage disease (GSD) in their livers. Focal necrosis was observed in male Gnmt-/- livers, whereas degenerative changes were found in the intermediate zones of female Gnmt-/- livers. In addition, hypoglycemia, increased serum cholesterol, and significantly lower numbers of white blood cells, neutrophils, and monocytes were observed in the Gnmt-/- mice. A real-time polymerase chain reaction analysis of genes involved in the gluconeogenesis pathways revealed that the following genes were significantly down-regulated in Gnmt-/- mice: fructose 1,6-bisphosphatase, phosphoenolpyruvate carboxykinase, and glucose-6-phosphate transporter.. Because Gnmt-/- mice phenotypes mimic those of patients with GNMT deficiencies and share several characteristics with GSD Ib patients, we suggest that they are useful for studies of the pathogenesis of congenital GNMT deficiencies and the role of GNMT in GSD and liver tumorigenesis.

Topics: Alanine Transaminase; Animals; ATPases Associated with Diverse Cellular Activities; Chromosome Mapping; Disease Models, Animal; Down-Regulation; Embryo, Mammalian; Female; Gene Expression; Gene Expression Profiling; Glycine N-Methyltransferase; Glycogen; Glycogen Storage Disease; Hepatitis, Chronic; Homocysteine; Liver; Methionine; Mice; Mice, Inbred C57BL; Mice, Knockout; Polymerase Chain Reaction; Proteins; S-Adenosylhomocysteine; S-Adenosylmethionine

Lafora disease is a progressive myoclonus epilepsy with onset typically in the second decade of life and death within 10 years. Lafora bodies, deposits of abnormally branched, insoluble glycogen-like polymers, form in neurons, muscle, liver, and other tissues. Approximately half of the cases of Lafora disease result from mutations in the EPM2A gene, which encodes laforin, a member of the dual-specificity protein phosphatase family that additionally contains a glycogen binding domain. The molecular basis for the formation of Lafora bodies is completely unknown. Glycogen, a branched polymer of glucose, contains a small amount of covalently linked phosphate whose origin and function are obscure. We report here that recombinant laforin is able to release this phosphate in vitro, in a time-dependent reaction with an apparent K(m) for glycogen of 4.5 mg/ml. Mutations of laforin that disable the glycogen binding domain also eliminate its ability to dephosphorylate glycogen. We have also analyzed glycogen from a mouse model of Lafora disease, Epm2a(-/-) mice, which develop Lafora bodies in several tissues. Glycogen isolated from these mice had a 40% increase in the covalent phosphate content in liver and a 4-fold elevation in muscle. We propose that excessive phosphorylation of glycogen leads to aberrant branching and Lafora body formation. This study provides a molecular link between an observed biochemical property of laforin and the phenotype of a mouse model of Lafora disease. The results also have important implications for glycogen metabolism generally.

Topics: Animals; Disease Models, Animal; Dual-Specificity Phosphatases; Glycogen; Glycogen Synthase; Lafora Disease; Male; Mice; Mice, Knockout; Mutation; Phosphorylation; Protein Tyrosine Phosphatases, Non-Receptor; Rabbits; Recombinant Proteins

Mice with liver-specific overexpression of dominant negative phosphorylation-defective S503A-CEACAM1 mutant (L-SACC1) developed chronic hyperinsulinemia resulting from blunted hepatic clearance of insulin, visceral obesity, and glucose intolerance. To determine the underlying mechanism of altered glucose homeostasis, a 2-h hyperinsulinemic euglycemic clamp was performed, and tissue-specific glucose and lipid metabolism was assessed in awake L-SACC1 and wild-type mice. Inactivation of carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) caused insulin resistance in liver that was mostly due to increased expression of fatty acid synthase and lipid metabolism, resulting in elevated intrahepatic levels of triglyceride and long-chain acyl-CoAs. Whole body insulin resistance in the L-SACC1 mice was further attributed to defects in insulin-stimulated glucose uptake in skeletal muscle and adipose tissue. Insulin resistance in peripheral tissues was associated with significantly elevated intramuscular fat contents that may be secondary to increased whole body adiposity (assessed by (1)H-MRS) in the L-SACC1 mice. Overall, these results demonstrate that L-SACC1 is a mouse model in which chronic hyperinsulinemia acts as a cause, and not a consequence, of insulin resistance. Our findings further indicate the important role of CEACAM1 and hepatic insulin clearance in the pathogenesis of obesity and insulin resistance.

Topics: Acyl Coenzyme A; Animals; Blood Glucose; Carcinoembryonic Antigen; Disease Models, Animal; Fatty Acid Synthases; Fatty Acid Transport Proteins; Glucose; Glucose Clamp Technique; Glucose Intolerance; Glucose-6-Phosphate; Glycogen; Hyperinsulinism; Insulin; Insulin Resistance; Lipoprotein Lipase; Liver; Mice; Mice, Knockout; Muscle, Skeletal; Triglycerides

Hepatic insulin resistance in the leptin-receptor defective Zucker fa/fa rat is associated with impaired glycogen synthesis and increased activity of phosphorylase-a. We investigated the coupling between phosphorylase-a and glycogen synthesis in hepatocytes from fa/fa rats by modulating the concentration of phosphorylase-a. Treatment of hepatocytes from fa/fa rats and Fa/? controls with a selective phosphorylase inhibitor caused depletion of phosphorylase-a, activation of glycogen synthase and stimulation of glycogen synthesis. The flux-control coefficient of phosphorylase on glycogen synthesis was glucose dependent and at 10 mm glucose was higher in fa/fa than Fa/? hepatocytes. There was an inverse correlation between the activities of glycogen synthase and phosphorylase-a in both fa/fa and Fa/? hepatocytes. However, fa/fa hepatocytes had a higher activity of phosphorylase-a, for a corresponding activity of glycogen synthase. This defect was, in part, normalized by expression of the glycogen-targeting protein, PTG. Hepatocytes from fa/fa rats had normal expression of the glycogen-targeting proteins G(L) and PTG but markedly reduced expression of R6. Expression of R6 protein was increased in hepatocytes from Wistar rats after incubation with leptin and insulin. Diminished hepatic R6 expression in the leptin-receptor defective fa/fa rat may be a contributing factor to the elevated phosphorylase activity and/or its high control strength on glycogen synthesis.

Topics: Animals; Carrier Proteins; Cells, Cultured; Diabetes Mellitus, Type 2; Disease Models, Animal; Female; Glycogen; Hepatocytes; Insulin; Insulin Resistance; Intracellular Signaling Peptides and Proteins; Leptin; Male; Obesity; Phosphoprotein Phosphatases; Phosphorylase a; Protein Subunits; Rats; Rats, Wistar; Rats, Zucker; Receptors, Cell Surface; Receptors, Leptin

Creatine supplementation may exert beneficial effects on muscle performance and facilitate peripheral glucose disposal in both rats and human subjects. The present study was undertaken to explore the effects of creatine supplementation on the ATP, creatine, phosphocreatine and glycogen content of white and red gastrocnemius and soleus muscles and on blood D-glucose and plasma insulin concentrations before and during an intravenous glucose tolerance test in Goto-Kakizaki rats, a current animal model of inherited type 2 diabetes mellitus. Creatine supplementation increased muscle creatine content, especially in the soleus muscle of young rats (+35.5-/+15.8%; d.f.=10; p<0.05), and lowered the insulinogenic index, i.e. the paired ratio between plasma insulin and blood D-glucose concentrations. The latter change was mainly attributable to a lowering of plasma insulin concentration. It is proposed, therefore, that creatine supplementation may improve the sensitivity to insulin in extrapancreatic sites in the present animal model of type 2 diabetes.

Topics: Adenosine Triphosphate; Animals; Blood Glucose; Body Weight; Creatine; Diabetes Mellitus, Type 2; Disease Models, Animal; Eating; Glucose Tolerance Test; Glycogen; Insulin; Male; Muscle, Skeletal; Rats; Rats, Inbred Strains

Laforin, encoded by the EPM2A gene, is a dual specificity protein phosphatase that has a functional glycogen-binding domain. Mutations in the EPM2A gene account for around half of the cases of Lafora disease, an autosomal recessive neurodegenerative disorder, characterized by progressive myoclonus epilepsy. The hallmark of the disease is the presence of Lafora bodies, which contain polyglucosan, a poorly branched form of glycogen, in neurons and other tissues. We examined the level of laforin protein in several mouse models in which muscle glycogen accumulation has been altered genetically. Mice with elevated muscle glycogen have increased laforin as judged by Western analysis. Mice completely lacking muscle glycogen or with 10% normal muscle glycogen had reduced laforin. Mice defective in the GAA gene encoding lysosomal alpha-glucosidase (acid maltase) overaccumulate glycogen in the lysosome but did not have elevated laforin. We propose, therefore, that laforin senses cytosolic glycogen accumulation which in turn determines the level of laforin protein.

Topics: Animals; Disease Models, Animal; Dual-Specificity Phosphatases; Genetic Predisposition to Disease; Glycogen; Lafora Disease; Mice; Mice, Transgenic; Phosphoric Monoester Hydrolases; Protein Tyrosine Phosphatases; Protein Tyrosine Phosphatases, Non-Receptor

An investigation was made to reveal the possible involvement of thyroid hormones, if any, in terazosin (an alfa-1 adrenergic receptor blocker) induced alterations in tissue lipid peroxidation (LPO) and in the concentration of different serum lipids. We determined the impact of terazosin on the changes in hypercholesterolemic (CCT) diet induced thyroid dysfunction; cardiac, renal and hepatic LPO and on serum glucose concentration in female Wister rats. Simultaneously levels of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), creatinine, alkaline phosphatase (ALP) activity, hepatic glycogen synthesis and total daily food consumption were studied as supporting parameters. While a decrease in the level of serum thyroid hormones, HDL-C and in hepatic glycogen content, was observed in CCT diet fed animals; it increased the concentration of other serum lipids, glucose and creatinine; ALP activity; tissue and serum LPO. However, following terazosin administration for 15 days to CCT diet fed animals, status of thyroid hormones and all other thyroid dependent parameters were reversed suggesting that the drug might be acting through an alteration in the thyroid functions.

Topics: Adrenergic alpha-Antagonists; Animals; Blood Glucose; Cholesterol, Dietary; Disease Models, Animal; Eating; Female; Glycogen; Heart; Hypercholesterolemia; Hyperglycemia; Hypoglycemic Agents; Hypolipidemic Agents; Kidney; Lipid Peroxidation; Lipids; Lipoproteins; Liver; Prazosin; Rats; Rats, Wistar; Thyroid Gland; Thyroxine; Triiodothyronine

Disturbance in glucose metabolism is a common feature in liver diseases and this is associated with skeletal muscle insulin resistance. However, the underlying molecular mechanisms are unclear. To characterize skeletal muscle insulin resistance associated with liver disease, we examined muscles from animals after an acute, 5 weeks perturbation of the common bile duct. Clinical findings, elevated plasma levels of liver enzymes and histological examinations confirmed cirrhosis.. : Cirrhotic animals were insulin resistant and this was associated with reduced glucose transport into muscles. Interestingly, activity in the proximal part of the insulin signaling cascade was not decreased, as evinced by increased activity of key enzymes in the signal to glucose transport. Expression of the glucose transporter, GLUT4, was normal. So together these results indicate that signaling downstream of PKB/Akt and/or the translocation of GLUT4 is impaired in skeletal muscle from cirrhotic animals.. In conclusion, in an animal model of liver cirrhosis whole body insulin resistance is associated with insulin resistance in skeletal muscles. Unlike other common forms of insulin resistance, muscles from cirrhotic animals have increased activity in the proximal insulin signaling cascade. This emphasizes the fact that skeletal muscle insulin resistance associated with liver cirrhosis is a unique entity.

Topics: Animals; Biological Transport, Active; Blotting, Western; Disease Models, Animal; Disease Progression; Follow-Up Studies; Glucose; Glucose Tolerance Test; Glucose Transporter Type 4; Glycogen; Insulin; Insulin Resistance; Liver Cirrhosis, Experimental; Male; Muscle, Skeletal; Rats; Rats, Wistar

Increasing evidence indicates that fetal metabolic stress may result in a variety of post-natal perturbations during brain development. The goal of the study was to determine the duration of hypoxia/ischemia that would elicit a demonstrable regional depression of metabolism in the fetal brain and further to examine several end-points to determine if the metabolic stress affects the developing brain. The uterine artery and uterine branch of the ovarian artery were occluded with aneurysm clamps for a period of 45 min, the clips removed and the metabolites in five regions of the perinatal brain were measured at 0, 2 and 6 h of reflow. Regional P-creatine, ATP and glucose levels were significantly depleted at the end of the 45 min occlusion. The levels of glycogen and glutamate at the end of the occlusion indicated a decreasing trend which was not significant. The concentration of citrate remained essentially unchanged at the end of the occlusion. To ensure that the insult was not lethal to the tissue, the recovery of the metabolites was examined at 2 and 6 h of reflow and generally the concentrations of the high-energy phosphates and glucose were normal or near-normal by 6 h of reperfusion in the five regions of the brain examined. The changes in the metabolites indicate that 45 min of hypoxia/ischemia is an appropriate model for studying neonatal development after fetal metabolic stress.

Topics: Adenosine Triphosphate; Animals; Brain; Creatine; Disease Models, Animal; Female; Fetal Hypoxia; Glucose; Glycogen; Hypoxia-Ischemia, Brain; Lactic Acid; Phosphates; Pregnancy; Rats; Rats, Sprague-Dawley; Severity of Illness Index; Uterus

The present study tested the hypothesis that the phosphorylation and regulation of metabolic proteins implicated in glucose homeostasis were impaired in the heart of the type 2 diabetic Zucker-diabetic-fatty (ZDF) rat model. The onset of hyperglycaemia in ZDF rats was not uniform, instead it either progressed rapidly (3-4 weeks) or was delayed (6-8 weeks). In both the early and late onset hyperglycaemic ZDF rats, AMPKalpha Thr172 phosphorylation in the heart was significantly decreased. In the early onset hyperglycaemic ZDF rats, PKB Ser473 phosphorylation was reduced, whereas Thr308 phosphorylation was significantly increased. In the late onset hyperglycaemic ZDF rats, PKB Ser473 phosphorylation was unchanged, but Thr308 phosphorylation remained elevated. Cardiac GLUT4 protein and mRNA expression were significantly reduced in the early onset hyperglycaemic ZDF rats, whereas increased protein expression was observed in the late onset hyperglycaemic ZDF rats. In conclusion, the present study has demonstrated that following a more rapid onset of hyperglycaemia, the type 2 diabetic heart is more prone to alterations in the signaling proteins implicated in glucose metabolism.

Topics: AMP-Activated Protein Kinases; Animals; Blood Glucose; Diabetes Mellitus, Type 2; Disease Models, Animal; Disease Progression; Glucose; Glucose Transporter Type 4; Glycogen; Glycogen Synthase Kinase 3; Hyperglycemia; Insulin; Male; Multienzyme Complexes; Myocardium; Phosphorylation; Protein Kinases; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins c-akt; Rats; Rats, Zucker; RNA, Messenger; Time Factors

D-mannose is an essential monosaccharide constituent of glycoproteins and glycolipids. However, it is unknown how plasma mannose is supplied. The aim of this study was to explore the source of plasma mannose. Oral administration of glucose resulted in a significant decrease of plasma mannose concentration after 20 min in fasted normal rats. However, in fasted type 2 diabetes model rats, plasma mannose concentrations that were higher compared with normal rats did not change after the administration of glucose. When insulin was administered intravenously to fed rats, it took longer for plasma mannose concentrations to decrease significantly in diabetic rats than in normal rats (20 and 5 min, respectively). Intravenous administration of epinephrine to fed normal rats increased the plasma mannose concentration, but this effect was negated by fasting or by administration of a glycogen phosphorylase inhibitor. Epinephrine increased mannose output from the perfused liver of fed rats, but this effect was negated in the presence of a glucose-6-phosphatase inhibitor. Epinephrine also increased the hepatic levels of hexose 6-phosphates, including mannose 6-phosphate. When either lactate alone or lactate plus alanine were administered as gluconeogenic substrates to fasted rats, the concentration of plasma mannose did not increase. When lactate was used to perfuse the liver of fasted rats, a decrease, rather than an increase, in mannose output was observed. These findings indicate that hepatic glycogen is a source of plasma mannose.

Topics: Administration, Oral; Alanine; Animals; Arabinose; Blood Glucose; Chlorogenic Acid; Diabetes Mellitus, Type 2; Disease Models, Animal; Epinephrine; Glucose; Glucose-6-Phosphatase; Glycogen; Glycogen Phosphorylase; Hexosephosphates; Imino Furanoses; Injections, Intravenous; Insulin; Lactic Acid; Liver; Male; Mannose; Models, Biological; Rats; Rats, Inbred Strains; Rats, Wistar; Sugar Alcohols

Recently, both asymmetrical dimethylarginine and IL-6 have been suggested to be associated with the induction and severity of single and multiple organ dysfunction. The aims of the present study were to elucidate if these factors were increased in an ischemia reperfusion (IR) model and whether pre-operative carbohydrate supplementation can reduce the risk factors along with the IR injury.. One group of male Wistar rats was fasted for 16 h (water ad libitum) prior to clamping the superior mesenteric artery (IR fasted n=14). A second group had ad libitum access to a carbohydrate solution prior to clamping (IR fasted CHO group n=11). Sham-fasted animals, which only received laparotomy and no clamping, served as controls (n=4).. Plasma urea and ALAT activity were both increased in the IR fasted animals when compared to the sham rats (P=0.007 and P<0.02, respectively). Furthermore, it was shown that IR fasted rats had increased ADMA and IL-6 concentration in plasma when compared to sham animals (P<0.02). Moreover, the GSH level in lung was significantly decreased in the IR fasted animals (P=0.014). IR CHO supplemented showed no significant increase of ALAT activity and decrease of lung GSH. Furthermore, significantly lower plasma urea, ADMA and IL-6 concentration was seen in the IR CHO supplemented group when compared to the IR fasted rats (P=0.028, P<0.01 and P<0.02, respectively). The liver glycogen concentration in IR fasted rats was 48% of that IR rats supplemented the carbohydrate mixture.. The present rat intestinal ischemia reperfusion model not only induces organ injury indicated by the classical parameters such as plasma urea and ALAT activity, but also increased plasma IL-6 and ADMA and decreased lung GSH concentration in IR fasted rats. Pre-operative supplementation with the carbohydrate mixture significantly lowered the plasma urea, IL-6 and ADMA concentrations and maintained lung GSH concentration. This indicates that pre-operative carbohydrate supplementation reduces post-operative organ injury.

Topics: Alanine Transaminase; Animals; Arginine; Blood Urea Nitrogen; Dietary Carbohydrates; Dietary Supplements; Disease Models, Animal; Glutathione; Glycogen; Interleukin-6; Liver; Male; Multiple Organ Failure; Preoperative Care; Random Allocation; Rats; Rats, Wistar; Reperfusion Injury; Risk Factors

We investigated the role of the kallikrein-kinin system in cardiac function and glucose utilization in the streptozotocin (STZ)-induced diabetic rat model using a gene transfer approach. Adenovirus harboring the human tissue kallikrein gene was administered to rats by intravenous injection at 1 week after STZ treatment. Human kallikrein transgene expression was detected in the serum and urine of STZ-induced diabetic rats after gene transfer. Kallikrein gene delivery significantly reduced blood glucose levels and cardiac glycogen accumulation in STZ-induced diabetic rats. Kallikrein gene transfer also significantly attenuated elevated plasma triglyceride and cholesterol levels, food and water intake, and loss of body weight gain, epididymal fat pad, and gastrocnemius muscle weight in STZ-induced diabetic rats. However, these effects were blocked by icatibant, a kinin B2 receptor antagonist. Cardiac function was significantly improved after kallikrein gene transfer as evidenced by increased cardiac output and +/-delta P/delta t (maximum speed of contraction/relaxation), along with elevated cardiac sarco(endo)plasmic reticulum (Ca2+ + Mg2+)-ATPase (SERCA)-2a, phosphorylated phospholamban, NOx and cAMP levels, and GLUT4 translocation into plasma membranes of cardiac and skeletal muscle. Kallikrein gene delivery also increased Akt and glycogen synthase kinase (GSK)-3beta phosphorylation, resulting in decreased GSK-3beta activity in the heart. These results indicate that kallikrein through kinin formation protects against diabetic cardiomyopathy by improving cardiac function and promoting glucose utilization and lipid metabolism.

Topics: Adenoviridae; Animals; Blood Glucose; Cardiomyopathies; Diabetes Mellitus, Experimental; Disease Models, Animal; Genetic Vectors; Glycogen; Humans; Kallikreins; Lipids; Male; Myocardium; Rats; Rats, Sprague-Dawley; Recombinant Proteins; Transfection

O-linked N-acetylglucosamine (O-GlcNAc) is an evolutionarily conserved modification of nuclear pore proteins, signaling kinases, and transcription factors. The O-GlcNAc transferase (OGT) catalyzing O-GlcNAc addition is essential in mammals and mediates the last step in a nutrient-sensing "hexosamine-signaling pathway." This pathway may be deregulated in diabetes and neurodegenerative disease. To examine the function of O-GlcNAc in a genetically amenable organism, we describe a putative null allele of OGT in Caenorhabditis elegans that is viable and fertile. We demonstrate that, whereas nuclear pore proteins of the homozygous deletion strain are devoid of O-GlcNAc, nuclear transport of transcription factors appears normal. However, the OGT mutant exhibits striking metabolic changes manifested in a approximately 3-fold elevation in trehalose levels and glycogen stores with a concomitant approximately 3-fold decrease in triglycerides levels. In nematodes, a highly conserved insulin-like signaling cascade regulates macronutrient storage, longevity, and dauer formation. The OGT knockout suppresses dauer larvae formation induced by a temperature-sensitive allele of the insulin-like receptor gene daf-2. Our findings demonstrate that OGT modulates macronutrient storage and dauer formation in C. elegans, providing a unique genetic model for examining the role of O-GlcNAc in cellular signaling and insulin resistance.

Topics: Animals; Caenorhabditis elegans; Carmine; Disease Models, Animal; DNA Primers; Fluorescent Antibody Technique; Glycogen; Immunoblotting; Insulin Resistance; Larva; Mutation; N-Acetylglucosaminyltransferases; Oxazines; Polymerase Chain Reaction; Signal Transduction; Trehalose; Triglycerides

Experimental evidence suggests storing lungs inflated with oxygen and with oxidizable substrate improves results of lung transplantation. Glucose is included in the low-potassium-dextran (LPD) solution Perfadex to achieve this goal. The authors hypothesized that other substrates might be more effective. Rat lungs were stored for 6 or 24 hr in LPD solution with the following carbon-13--labeled substrates: 5 mM glucose (Perfadex group), 32 mM pyruvate (pyruvate group), or both (combination group). Metabolism was assessed by magnetic resonance spectroscopy. Small amounts of exogenous glucose were oxidized in the Perfadex group. In contrast, exogenous pyruvate was the major substrate oxidized in the pyruvate and combination groups (P<0.01 vs. Perfadex). Carbon-13--labeled glucose and glycogen were detected in the pyruvate group, suggesting that gluconeogenesis and glycogen synthesis occur in glucose-deprived lungs. Lungs for transplantation metabolize substrates through both anabolic and catabolic pathways. These reactions may be important in designing improved solutions for lung preservation.

Topics: Animals; Carbon Isotopes; Dextrans; Disease Models, Animal; Gluconeogenesis; Glucose; Glycogen; Hypothermia, Induced; Lung; Lung Transplantation; Magnetic Resonance Spectroscopy; Male; Models, Animal; Organ Preservation; Organ Preservation Solutions; Oxygen; Potassium; Pyruvates; Pyruvic Acid; Rats; Rats, Sprague-Dawley; Time Factors

Guarana is widely consumed by athletes, either in supplements or in soft drinks, under the belief that it presents ergogenic and "fat burning" effects. We examined the effect of guarana supplementation (14 days) upon aspects of lipid metabolism in sedentary (C) and trained rats (T).. To isolate the effect of caffeine from that of other components of guarana, we adopted two different doses of whole extract (G1-0.130 g/kg; G2-0.325 g/kg) or decaffeinated extract (DG1, DG2). Body weight, food and water intake; muscle fat content, oleate incorporation, glycogen content, and carnitine palmitoyltransferase I (CPT I) activity and mRNA expression; along with plasma lactate concentration, were assessed.. Muscle oleate incorporation was decreased in rats receiving decaffeinated guarana in relation to G1 and G2; as was CPT I mRNA expression in the gastrocnemius. Whole extract supplementation, but not DG induced reduced plasma lactate concentration in trained rats. G1 showed higher muscle glycogen content compared with all other groups. The results show an effect of guarana on aspects of lipid metabolism, which is abolished by decaffeination.. The changes in lipid metabolism of supplemented rats herein reported are associated with the methylxanthine content of guarana.

Topics: Animals; Caffeine; Dietary Supplements; Disease Models, Animal; Dose-Response Relationship, Drug; Gene Expression Regulation; Glycogen; Humans; Lipid Metabolism; Male; Muscle, Skeletal; Oleic Acid; Paullinia; Physical Conditioning, Animal; Plant Extracts; Random Allocation; Rats; Rats, Wistar; RNA, Messenger; Xanthines

A novel glycogen phosphorylase inhibitor FR258900 was isolated from the cultured broth of a fungal strain No. 138354. We examined the hypoglycemic effects of FR258900 in diabetic animal models. FR258900 treatment significantly reduced the plasma glucose concentrations during oral glucose tolerance tests in diabetic mice models, including db/db mice and STZ-induced diabetic mice. Furthermore, FR258900 treatment resulted in rapid decrease in the plasma glucose levels in db/db mice. These improvements in glucose disposal were accompanied by increased liver glycogen contents, suggesting that the glucose lowering effects of FR258900 were attributed to suppressed hepatic glycogen breakdown and increased hepatic glycogen synthesis. Taken together, our results suggest that glycogen phosphorylase is a potentially useful target in new therapies against diabetes.

Topics: Animals; Blood Glucose; Diabetes Mellitus, Experimental; Disease Models, Animal; Fungi; Glycogen; Glycogen Phosphorylase; Hypoglycemic Agents; Insulin; Liver; Liver Glycogen; Mice; Mice, Inbred C57BL

The challenge of accurately predicting human clinical outcome based on preclinical data has led to a high failure rate of compounds in human clinical trials. A series of methods are described by which biosimulation can address these challenges and guide the design and evaluation of experimental and clinical protocols. Early compound development often proceeds on the basis of preclinical data from animal models. The systematic evaluation possible in a simulation can assist in the critical step of translating the preclinical outcomes to human physiology. Later in the process, clinical trials definitively establish a therapy's beneficial effects, as well as any adverse side effects. Biosimulation allows for the optimal design of clinical trials to ensure that key issues are addressed effectively and efficiently, and in doing so, improves the success rate of the trials.

Topics: Animals; Biological Assay; Clinical Trials as Topic; Computer Simulation; Diabetes Mellitus; Disease Models, Animal; Drug Design; Drug Evaluation, Preclinical; Drug Industry; Glycogen; Humans; Insulin; Liver; Male; Models, Biological; Rats; Rats, Wistar; Research Design; Species Specificity

Many of the spinocerebellar ataxias (SCAs) are caused by expansions of CAG trinucleotide repeats encoding abnormal stretches of polyglutamine. SCA3 or Machado-Joseph disease (MJD) is the commonest dominant inherited ataxia disease, with pathological phenotypes apparent with a CAG triplet repeat length of 61-84. In this study a mouse model of SCA3 has been examined which was produced using a human yeast artificial chromosome containing the MJD gene with a CAG triplet expansion of 84 repeats. These mice have previously been shown to possess a mild progressive cerebellar deficit. NMR-based metabolomics/metabonomics in conjunction with multivariate pattern recognition identified a number of metabolic perturbations in SCA3 mice. These changes included a consistent increase in glutamine concentration in tissue extracts of the cerebellum and cerebrum and spectra obtained from intact tissue using magic angle spinning (1)H-NMR spectroscopy. Furthermore, these profiles demonstrated metabolic abnormalities were present in the cerebrum, a region not previously implicated in SCA3. As well as an increase in glutamine both brain regions demonstrated decreases in GABA, choline, phosphocholine and lactate (representing the summation of lactate in vivo, and postmortem glycolysis of glucose and glycogen). The metabolic changes are discussed in terms of the formation of neuronal intranuclear inclusions associated with SCA3. This study suggests high-resolution (1)H-NMR spectroscopy coupled with pattern recognition may provide a rapid method for assessing the phenotype of animal models of human disease.

Topics: Animals; Ataxin-3; Brain; Cerebellum; Choline; Disease Models, Animal; gamma-Aminobutyric Acid; Glucose; Glutamine; Glycogen; Humans; Lactic Acid; Machado-Joseph Disease; Magnetic Resonance Spectroscopy; Mice; Mice, Transgenic; Nerve Tissue Proteins; Nuclear Proteins; Phenotype; Phosphorylcholine; Repressor Proteins; Telencephalon; Transcription Factors; Trinucleotide Repeat Expansion

Hexachlorobenzene (HCB) is a fungicide of well-known porphyrinogenic ability, which induces an experimental porphyria that resembles human porphyria cutanea tarda (PCT) in several animal species. It has been demonstrated that high glucose ingestion prevents porphyria development, and high-fat/high-protein diets enhance HCB porphyrinogenic ability. On the contrary, a diet rich in carbohydrates reduces HCB effects. The aim of this work was to study HCB effects on glycogen synthesis and degradation, as well as on glucose synthesis and transport, in order to elucidate whether would justify the beneficial use of carbohydrates in this porphyria. Rats were treated with HCB dissolved in corn oil (five daily doses 100mg/kg body weight). Results showed that: (1) HCB caused an increase in glycogen content; (2) glycogen synthase activity increased three times, and phosphorylase activity decreased about 40% due to fungicide intoxication. The effect of HCB on these two activities accounted for the higher glycogen content observed in treated animals; (3) three gluconeogenic enzymes were reduced 30-50%; (4) glucose uptake in the liver decreased in all weeks studied. The alterations found in glucose synthesis, its uptake in liver and other tissues, and its release from glycogen might contribute to the biochemical porphyria picture and would account for the effect of glucose above mentioned.

Topics: Animals; Disease Models, Animal; Female; Fungicides, Industrial; Gluconeogenesis; Glucose; Glycogen; Hexachlorobenzene; Liver; Porphyrias; Porphyrins; Rats; Rats, Wistar

Genetically modified mice are important models for evaluation of potential gene therapies for human diseases. However, their small size often precludes the use of clinically feasible methods for vector delivery, therefore, alternative methods must be used. We have developed a gel-based method for delivery of recombinant adeno-associated virus vectors to the mouse diaphragm, an important target organ for many myopathic diseases. We hypothesized that delivery of vectors in a viscous solution would increase transduction by providing a longer exposure time to target cells. We demonstrate that gel-mediated delivery of rAAV serotypes 1, 2, and 5 results in higher transduction efficiencies than free vectors alone when administered in vivo to mouse diaphragms. We further establish greater tropism of rAAV1 vectors for the diaphragm compared to serotypes 2 and 5. This report describes a novel method for efficient delivery of rAAV vectors to the mouse diaphragm and is the first demonstration of gene transfer to the diaphragm using recombinant adeno-associated virus vectors.

Topics: Animals; beta-Galactosidase; Dependovirus; Diaphragm; Disease Models, Animal; Gene Transfer Techniques; Genetic Therapy; Genetic Vectors; Genome, Viral; Glucosidases; Glycogen; Humans; Mice; Mice, Inbred C57BL; Muscle, Skeletal; Recombinant Proteins

The great resistance of muscle to ischemia was used to study blood flow-dependent phenomena produced by anesthetic drugs in this condition. A short reperfusion period was used in order to favor metabolic changes indicative of an effect of chlorpromazine (CPZ) on blood flow. Gracilis muscles of dogs were submitted to 5 h of ischemia and 30 min of reperfusion. CPZ-treated animals were injected I.V. (2 mg/kg) 10 min before the beginning of ischemia. Biopsies provided the material for tissue measurements. Lactate content and pH were determined in blood samples collected from a muscle efferent vein. In both the CPZ-treated and nontreated groups, ischemia induced a decline in muscle glycogen content, with a corresponding increase in muscle lactate and a decrease in mitochondrial respiratory control ratio. After 30 min of reperfusion, tissue levels of lactate did not attain preischemic values but showed a clear decline in the two experimental groups, evidencing the reversible state of the muscle. All other metabolic parameters remained unchanged. Mitochondrial respiratory control remained functional during ischemia and reperfusion. Blood pH displayed similar changes in both groups. There was no metabolic indication that the drug affected blood flow during early reperfusion and/or of a greater sensitivity of muscle endothelial cells to anesthetic drugs.

Topics: Animals; Chlorpromazine; Disease Models, Animal; Dogs; Glycogen; Hydrogen-Ion Concentration; Ischemia; Lactates; Mitochondria, Muscle; Muscle Contraction; Muscle, Skeletal; Musculoskeletal Physiological Phenomena; Reference Values; Reperfusion Injury

In the present work, the authors' previous studies of a "distant action", exerted by an intestinal pathogen (Cryptosporidium parvum) on the liver of experimentally infected baby rats, were extended to include shifts in the quantity of glycogen, protein and nuclear DNA in the host liver at different degrees of infection. One of the outcomes of this work is the discovery of a very quick response of hepatocytes and a high sensitivity of rat liver to parasitic invasion even at a weak intensity of infection. 85-90 h after oocyst feeding to rats, glycogen quantity in their livers was 2.5 times lower that in the control. This suggests that the infected host liver worked under energetic starvation conditions. The proposed coefficients of general infection (I) and infection with intracellular stages (F) made it possible to distinguish between the total abundance of parasites in the host intestine during the whole period of infection, and the number of feeding intracellular stages available by the moment of autopsy. The glycogen amount in rat hepatocytes does not depend on I, and negatively correlates with F. Unlike, the protein content in hepatocytes positively correlates with I, being independent of F. Despite the obvious deficiency of amino acids in the infected rats, as a consequence of cryptosporidiosis-induced malabsorption, the protein synthesis in their hepatocytes was not at all inhibited but, on the contrary, much activated. This is a most characteristic feature of the distant action of C. parvum on the liver of parasitized host. With C. parvum infection, the share of polyploid hepatocytes does not correlate with either I, or F. However, compared to the control, the mean values of relative numbers of polyploid cells in weakly, moderately, and heavily infected animals (according to I values) were higher by 20, 100 and 100%, respectively. In hepatocyte nuclei of C. parvum infected rats, the total area of nucleoli increases almost by 30%. The above changes are discussed in terms of both the liver compensatory response to the existing pathology (diarrhea), and the host-parasite relationships. Studies into the distant action of an intestinal pathogen (C. parvum) on non-intestinal organs (liver) of the infected host may be qualified as a new and original approach to pathogenesis of protozoan infections (coccidioses sensu lato), to which young host specimens are known to be most susceptible.

Topics: Animals; Animals, Suckling; Cell Nucleolus; Cell Nucleus; Cryptosporidiosis; Cryptosporidium parvum; Diarrhea; Disease Models, Animal; Glycogen; Hepatocytes; Intestine, Small; Polyploidy; Proteins; Rats; Rats, Wistar

This study tested the robustness of our computational model of myocardial metabolism by comparing responses to two different inputs with experimental data obtained in pigs under similar conditions. Accordingly, an abrupt and a gradual reduction in coronary flow of similar magnitude were implemented and used as model input. After flow reductions reached 60% from control values, ischemia was kept constant for 60 min in both groups. Our hypotheses were that: (1) these two flow-reduction profiles would result in different transients (concentrations and flux rates) while having similar steady-state values and (2) our model-simulated responses would predict the experimental results in an anesthetized swine model of myocardial ischemia. The two different ischemia-induction patterns resulted in the same decrease in steady-state MVO2 and in similar steady-state values for metabolite concentrations and flux rates at 60 min of ischemia. While both the simulated and experimental results showed decreased glycogen concentration, accumulation of lactate, and net lactate release with ischemia, the onset of glycogen depletion and the switch to lactate efflux were more rapid in the experiments than in the simulations. This study demonstrates the utility of computer models for predicting experimental outcomes in studies of metabolic regulation under physiological and pathological conditions.

Topics: Animals; Computer Simulation; Coronary Circulation; Disease Models, Animal; Energy Metabolism; Glycogen; Lactic Acid; Myocardial Ischemia; Myocardium; Oxygen Consumption; Swine; Time Factors

Clinical studies of enzyme replacement therapy for Pompe disease have indicated that relatively high doses of recombinant human acid alpha-glucosidase (rhGAA) may be required to reduce the abnormal glycogen storage in cardiac and skeletal muscles. This may be because of inefficient cation-independent mannose 6-phosphate receptor (CI-MPR)-mediated endocytosis of the enzyme by the affected target cells. To address this possibility, we examined whether the addition of a high affinity ligand to rhGAA would improve its delivery to these cells. Chemical conjugation of high mannose oligosaccharides harboring mono- and bisphosphorylated mannose 6-phosphates onto rhGAA (neo-rhGAA) significantly improved its uptake characteristics by muscle cells in vitro. Infusion of neo-rhGAA into Pompe mice also resulted in greater delivery of the enzyme to muscle tissues when compared with the unmodified enzyme. Importantly, this increase in enzyme levels was associated with significantly improved clearance of glycogen ( approximately 5-fold) from the affected tissues. These results suggest that CI-MPR-mediated endocytosis of rhGAA is an important pathway by which the enzyme is delivered to the affected lysosomes of Pompe muscle cells. Hence, the generation of rhGAA containing high affinity ligands for the CI-MPR represents a strategy by which the potency of rhGAA and therefore the clinical efficacy of enzyme replacement therapy for Pompe disease may be improved.

Topics: alpha-Glucosidases; Animals; Disease Models, Animal; Glycogen; Glycogen Storage Disease Type II; Mannosephosphates; Mice; Muscles; Myoblasts; Oligosaccharides; Protein Transport

To develop and evaluate the efficacy of diabetes-targeted cell therapies in humans, a reliable model in larger animals is highly desirable. This article reports the surgical technique of total pancreatectomy in pigs and the biochemical analysis of the characteristics of totally pancreatectomized pigs.. Surgical total pancreatectomy was conducted in 23 pigs. Blood glucose, insulin, biochemistries, activity index, and intravenous glucose tolerance test (IVGTT) were examined to assess the pathophysiological profiles of diabetic pigs.. A total of 14 pigs successfully underwent total pancreatectomy without requiring biliary reconstruction and were analyzed in the present study. Activity index was decreased from day 5 on and the mean survival of totally pancreatectomized pigs was 7.6 +/- 2.7 days. No endogenous insulin secretion was confirmed in these pigs. Pigs which received total pancreatectomy demonstrated significantly higher levels of ketone bodies. IVGTT performed within 4 days after total pancreatectomy showed a spontaneous decrease in blood glucose levels despite an absence of endogenous insulin secretion. IVGTT on day 5 or later showed continued hyperglycemia in pigs with total pancreatectomy. Histological examination showed atrophy of hepatocytes and decreased glycogen storage in the liver and decreased mucus production of the small intestine.. This article describes a porcine model of diabetes created by total pancreatectomy and it analyzes the pathophysiological profiles in the animals. The present study has suggested that IVGTT on day 5 or later after total pancreatectomy is a reliable method to evaluate the efficacy of cell therapies.

Topics: Alanine Transaminase; Animals; Area Under Curve; Aspartate Aminotransferases; Atrophy; Blood Glucose; Blood Urea Nitrogen; Body Weight; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 1; Diarrhea; Disease Models, Animal; Glucose Tolerance Test; Glycogen; Hepatocytes; Intestinal Mucosa; Ketone Bodies; L-Lactate Dehydrogenase; Liver; Pancreatectomy; Potassium; Swine

Ultrastructural data on acute right ventricular pressure load in pigs are rare.. In control (n = 7) and banding groups (n = 6), right ventricular pressure (micromanometry) and function (sonomicrometry) were measured. Right ventricular pressure was increased 2.5-fold in the banding group by pulmonary artery constriction. Right ventricular biopsies were taken at baseline and after 6 h and processed for electron microscopy. Parameters of cellular injury were determined stereologically. Three perfusion -fixed hearts were investigated qualitatively in each group.. Stereology revealed an increase in the sarcoplasmic volume fraction and the cellular edema index in the banding group ( p < 0.05). Mitochondrial surface-to-volume ratio and volume fraction did not show significant alterations. Subendocardial edema and small amounts of severely injured myocytes were observed in the perfusion-fixed hearts after banding. Ultrastructure was normal in controls. After an initial increase, the right ventricular work index declined progressively in the banding group but remained unchanged in controls.. Ultrastructural alterations resulting from acute right ventricular pressure load were characterized by edema of subendocardial myocytes and single cell necrosis. Focal adrenergic overstimulation and mechanical stress are probably more relevant in the pathogenesis of these lesions than ischemia.

Topics: Acute Disease; Animals; Blood Pressure; Disease Models, Animal; Glycogen; Heart; Heart Ventricles; Microscopy, Electron; Mitochondria, Heart; Myocardium; Myocytes, Cardiac; Perfusion; Pulmonary Artery; Swine; Vasoconstriction

Metabolic interventions improve performance during demand-induced ischemia by reducing myocardial lactate production and improving regional systolic function. We tested the hypotheses that 1) stimulation of glycolysis would increase lactate production and improve ventricular wall motion, and 2) the addition of fatty acid oxidation inhibition would reduce lactate production and further improve contractile function. Measurements were made in anesthetized open-chest swine hearts. Three groups, hyperglycemia (HG), HG + oxfenicine (HG + Oxf), and control (CTRL), were treated under aerobic conditions and during demand-induced ischemia. During demand-induced ischemia, HG resulted in greater lactate production and tissue lactate content but had no significant effect on glucose oxidation. HG + Oxf significantly lowered lactate production and increased glucose oxidation compared with both the CTRL and HG groups. Myocardial energy efficiency was greater in the HG and HG + Oxf groups under aerobic conditions but did not change during demand-induced ischemia. Thus enhanced glycolysis resulted in increased energy efficiency under aerobic conditions but significantly enhanced lactate production with no further improvement in function during demand-induced ischemia. Partial inhibition of free fatty acid oxidation in the presence of accelerated glycolysis increased energy efficiency under aerobic conditions and significantly reduced lactate production and enhanced glucose oxidation during demand-induced ischemia.

Topics: Animals; Coronary Circulation; Disease Models, Animal; Fatty Acids, Nonesterified; Glycogen; Glycolysis; Hyperglycemia; Lactic Acid; Myocardial Ischemia; Myocardium; Oxidation-Reduction; Physical Conditioning, Animal; Sus scrofa; Ventricular Function, Left

Compared with normal hearts, those with pathology (hypertrophy) are less tolerant of metabolic stresses such as ischemia. Pharmacologic intervention administered prior to such stress could provide significant protection. This study determined, firstly, whether the pentose sugar ribose, previously shown to improve postischemic recovery of energy stores and function, protects against ischemia when administered as a pretreatment. Secondly, the efficacy of this same pretreatment protocol was determined in hearts with pathology (hypertrophy). For study 1, Sprague-Dawley rats received equal volumes of either vehicle (bolus i.v. saline) or ribose (100 mg/kg) before global myocardial ischemia. In study 2, spontaneously hypertensive rats (SHR; blood pressure approximately 200/130) with myocardial hypertrophy underwent the same treatment protocol and assessments. In vivo left ventricular function was measured and myocardial metabolites and tolerance to ischemia were assessed. In normal hearts, ribose pretreatment significantly elevated the heart's energy stores (glycogen), and delayed the onset of irreversible ischemic injury by 25%. However, in vivo ventricular relaxation was reduced by 41% in the ribose group. In SHR, ribose pretreatment did not produce significant elevations in the heart's energy or improvements in tolerance to global ischemia, but significantly improved ventricular function (maximal rate of pressure rise (+dP/dt(max)), 25%; normalized contractility ((+dP/dt)/P), 13%) despite no change in hemodynamics. Thus, administration of ribose in advance of global myocardial ischemia does provide metabolic benefit in normal hearts. However, in hypertrophied hearts, ribose did not affect ischemic tolerance but improved ventricular function.

Topics: Adenosine Triphosphate; Anaerobic Threshold; Animals; Cardiotonic Agents; Disease Models, Animal; Drug Administration Schedule; Glycogen; Hypertension; Hypertrophy, Left Ventricular; Injections, Intravenous; Male; Myocardial Ischemia; Myocardium; Phosphocreatine; Rats; Rats, Sprague-Dawley; Ribose; Structure-Activity Relationship; Ventricular Function, Left; Ventricular Function, Right

Prolonged atrial fibrillation (AF) results in electrical, structural, and gap-junctional remodeling. We examined the reversibility of the changes in (ultra)structure and gap junctions.. Four groups of goats were used: (1) sinus rhythm (SR), (2) 4 months' AF (4 mo AF), (3) 2 months' SR after 4 mo AF (2 mo post-AF), and (4) 4 months' SR after 4 mo AF (4 mo post-AF). Atria were characterized electrophysiologically, (ultra)structure was studied by light and electron microscopy, and structural and gap-junctional protein expression was studied by immunohistochemistry or Western blotting. The atrial effective refractory period had completely returned to normal values 2 mo post-AF. Induced AF episodes still lasted for minutes at 2 and 4 mo post-AF, compared with seconds in the SR group. Structural abnormalities were still present at 2 and 4 mo post-AF, although to a lesser extent. The increased atrial myocyte diameter was back to normal at 4 mo post-AF. The number of myocytes with severe myolysis had almost normalized 4 mo post-AF, whereas myocytes with mild myolysis remained significantly increased. Extracellular matrix area fraction after 4 mo AF was similar to SR. However, the extracellular matrix fraction per myocyte had increased after 4 mo AF and remained higher post-AF. Changes in expression of structural proteins were partially restored post-AF. The reduction of connexin 40 that was observed during AF was completely reversed at 4 mo post-AF.. Recovery from structural remodeling after 4 mo AF is a slow process and is still incomplete 4 mo post-AF. Several months post-AF, the duration of AF episodes is still prolonged (minutes).

Topics: Animals; Atrial Fibrillation; Cardiac Pacing, Artificial; Cell Size; Connexins; Disease Models, Animal; Disease Progression; Electrophysiologic Techniques, Cardiac; Gap Junctions; Glycogen; Goats; Heart Atria; Immunohistochemistry; Myocardium; Recovery of Function; Reference Values; Remission Induction

A liver transplant is considered today to be the only effective therapeutic solution for many otherwise intractable hepatic disorders. However, liver transplantation is beset by shortage of donors. Over the years, many liver support systems have been developed to supply the liver functions, mostly as a bridge to transplantation. Transplantation of isolated hepatocytes (HcTx) instead of whole liver has constituted one of the most appealing possibilities to treat several diseases. We compared two different models of HcTx in a surgical model of acute liver failure in pigs, using microencapsulated hepatocytes (MHcTx) and hepatocytes attached to a porcine biomatrix (PBMHcTx), both transplanted into peritoneum. The collected data were survival, laboratory findings, hemodynamic parameters, light microscopy, histology, MTT, and glycogen content. The group with PBMHcTx has a better outcome than the group with MHcTx (p < 0.05). Histology showed normal morphology of the hepatocytes, high glycogen content, 75% viability, positive MTT, and 95% adhesion of the hepatocytes to the biomatrix. Our biomatrix (PBM) provides cell-to-cell contact and interaction with extracellular matrix, which have been shown to play major roles in hepatocyte survival and physiologic regulation of gene expression, and guarantee a prompt engraftment and an adequate neovascularization. PBMHcTx is a useful method to treat acute liver failure and it indicates a possible liver-direct gene therapy in the treatment of inherited and acquired disorders.

Topics: Animals; Animals, Newborn; Biocompatible Materials; Cell Adhesion; Cell Size; Cell Survival; Disease Models, Animal; Drug Compounding; Extracellular Matrix; Glycogen; Graft Survival; Hepatocytes; Liver Failure, Acute; Male; Survival Rate; Sus scrofa; Tissue Transplantation; Treatment Outcome

Previously, in murine models of acid maltase deficiency (AMD), we demonstrated that intravenous administration of an improved adenovirus (Ad) vector encoding human acid alpha glucosidase (hGAA) resulted in liver transduction, followed by high-level hepatocyte-mediated secretion of hGAA into the plasma space. The hGAA secreted by the liver was taken up and targeted to muscle cell lysosomes. The levels of hGAA achieved by this approach resulted in clearance of lysosomal glycogen accumulations; in some muscle tissues the effect was prolonged (>6 months). We next wished to demonstrate whether this approach could be generalized across divergent species. To accomplish this goal, we determined whether a similar approach would also result in efficacy, but in a quail model of AMD.. An [E1-, E2b-]Ad vector encoding hGAA was intravenously injected into AMD quails. At several time points thereafter, plasma, liver, and multiple muscle tissues were assayed for evidence of hGAA gene expression, liver-mediated hGAA secretion, uptake of hGAA by skeletal muscles, and evidence of glycogen correction in AMD skeletal muscles. These results were compared with those obtained from mock-injected AMD or wild-type quails.. Intravenous [E1-, E2b-]Ad/hGAA vector injection resulted in high-level liver transduction and hepatic secretion of precursor forms of hGAA. The hepatically secreted hGAA was found to not only be efficiently taken up by cardiac and skeletal muscles, but was also proteolytically cleaved and processed equivalently to the quail-GAA protein detected in wild-type quails. The observations suggest that the signals regulating muscle cell uptake (but not proteolytic cleavage) of lysosomal enzymes are conserved and recognized across divergent species of vertebrates. Importantly, once localized to skeletal muscle lysosomes, the hGAA was able to effectively clear the glycogen accumulations present in AMD quail muscles.. Adenovirus-mediated transduction of the hGAA gene, followed by hepatic secretion, uptake, and cross-correction of the pathologic glycogen accumulation noted in multiple muscles of both the AMD mouse and AMD quail, adds support to the notion that gene transfer strategies (Ad-mediated or other agents) targeting liver tissues with the hGAA gene are likely to be highly efficacious in humans affected by AMD.

Topics: Adenoviridae; alpha-Glucosidases; Animals; Blotting, Western; Disease Models, Animal; Gene Transfer Techniques; Genetic Therapy; Genetic Vectors; Glucan 1,4-alpha-Glucosidase; Glycogen; Humans; Immunoblotting; Liver; Lysosomes; Muscle Cells; Muscle, Skeletal; Muscles; Quail; Time Factors; Tissue Distribution

To study whether ACE inhibition and AT-II receptor blockade modulates myocardial glucose uptake during ischemia and reperfusion.. We developed a method for in vivo sampling of large trans-myocardial tissue samples from beating pig hearts and in vitro measurement of sarcolemmal glucose transport, in a series of experiments in which hearts were exposed to stimuli (glucose-insulin and pacing) known to promote cellular glucose transport. In the subsequent study we compared three experimental groups: (i) ACE inhibition (ACE-I, n = 6): increasing oral doses of benazepril up to 40 mg daily for 3 weeks, (ii) angiotensin II receptor antagonist (AT II-A, n = 7): increasing oral doses of valsartan up to 320 mg for 3 weeks, (iii) control (n = 7). Samples were harvested at baseline, following 20 min of regional ischemia, and following 5 and 15 min of reperfusion. The samples were incubated with 3-O-methylglucose (MeGlu), and cellular MeGlu uptake was measured.. Insulin-glucose, pacing, and ischemia increased cellular MeGlu transport two- to fourfold (p < 0.001). Cellular MeGlu transport was increased in ACE-I and AT II-A animals during reperfusion (p < 0.001), but not at baseline or during ischemia, compared with controls.. Enhanced capacity for glucose transport during reperfusion may be a mechanism underlying the beneficial effects of ACE inhibition and AT II-antagonism in ischemic heart disease.

Topics: Adenosine Triphosphate; Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Animals; Blood Pressure; Cardiac Pacing, Artificial; Cell Membrane; Disease Models, Animal; Female; Glucose; Glucose Transporter Type 4; Glycogen; Heart Rate; Infusions, Intravenous; Insulin; Male; Models, Cardiovascular; Monosaccharide Transport Proteins; Muscle Proteins; Myocardial Ischemia; Myocardial Reperfusion; Myocardium; Renin; Swine; Systole; Time Factors

Kupffer cells are the tissue macrophages in the liver and play an important role in the defense mechanisms of the body. However, their role in liver function and hepatocellular activity remains unclear. This study was therefore undertaken to investigate the effect of gadolinium chloride-induced Kupffer cell dysfunction on liver function and hepatocellular signaling activity in mice and to establish an animal model for studying the role of Kupffer cells in vivo. Kunming mice were intraperitoneally injected with different doses of gadolinium chloride (GdCl3), a selective inhibitor of Kupffer cells, and the mice were sacrificed at different time periods following the drug administration. Hepatotoxicity and Kupffer cell function, as well as the levels of signaling molecules and inflammatory mediators in liver tissue, were measured. We demonstrated that the administration of 10-20 mg/kg GdCl3 caused apoptosis of Kupffer cells and blocked the Kupffer cell effector function, as shown by a decrease in CD68 expression and phagocytic activity. In addition, the NO, PGE2 and cAMP levels in the liver were also reduced significantly. Furthermore, 20 mg/kg GdCl3 decreased the levels of cNOS, PKC and NF-kappaB p65 expression by 26.6, 68 and 64%, respectively. In contrast, hepatotoxicity was not observed when the same doses of GdCl3 were used. Moreover, we found that Kupffer cell function and the NO, PGE2 and cAMP contents, as well as PKC and NF-kappaB p65 levels in the liver were only partially, but not fully recovered in up to six days following 20 mg/kg GdCl3 injection. However, the administration of higher doses of GdCl3 (40 mg/kg) caused both hepatotoxicity and Kupffer cell necrosis, as well as an increased release of TNF, NO, and PGE2 in the liver. These results indicate that administration of suitable doses of GdCl3 blocked the effector function of Kupffer cells selectively, but did not cause liver parenchymal cell toxicity, and provide a frame-work for the establishment of an animal model for studying the role of Kupffer cells in signaling in the liver. Lastly, the present study also provides evidence that shows there is a positive association between the expression of cAMP, PKC, or NF-kappaB and the levels of NO, PGE2 and TNF in the liver of Kupffer-cell-blocked mice, and suggests that Kupffer cells may play a part in mediating liver function and hepatocellular activity.

Topics: Adenosine Triphosphatases; Animals; Antigens, CD; Antigens, Differentiation, Myelomonocytic; Apoptosis; Cell Line; Cyclic AMP; Dinoprostone; Disease Models, Animal; Dose-Response Relationship, Drug; Gadolinium; Glycogen; Image Processing, Computer-Assisted; Immunohistochemistry; In Situ Hybridization; Kupffer Cells; Liver; Mice; Microscopy, Electron; Necrosis; NF-kappa B; Phagocytosis; Signal Transduction; Time Factors

The study is undertaken to determine the effect of adrenal corticosteroid depletion after adrenalectomy on carbohydrate, protein and fat metabolism as well as maturation and functional efficacy of the immunocompetent cells. Beside biochemical and hematological parameters, whether in vivo glucocorticoid depletion has any modulatory effects on splenic macrophage responses to bacterial challenge with regards to intracellular killing, nitric oxide release and cellular integrity, were determined. Major findings of our study indicate that blood glucose, urea and total inorganic phosphate levels showed a time dependent increase in adrenalectomized rats compared to control. Total glycogen content in liver was decreased gradually due to adrenal corticosteroid insufficiency. Hematological parameters like hemoglobin concentration, hematocrit value, total leukocyte count and differential count were also found to increase in the adrenalectomized group with respect to intact group. From the functional study of immunocompetent cells, intracellular killing capacity of splenic macrophages recovered from control and adrenalectomized rats after 10 and 20 days of adrenalectomy showed no significant alteration; however, the function of splenic macrophages recovered from rats after 30 days of adrenalectomy showed altered response. Nitric oxide released from splenic macrophages of adrenalectomized rats was less than that of control animal even after stimulation with lipopolysaccharide. DNA fragmentation assay showed a lesser degree of fragmentation of splenic macrophages obtained from adrenalectomized rats indicating, apoptotic death of cells in this group decreases. Adrenal corticosteroid insufficiency due to adrenalectomy interferes with metabolic and hematopoietic functions and modulates the development and maintenance of normal immunitary status, which in turn influences the inflammatory response.

Topics: Adrenal Cortex; Adrenalectomy; Animals; Blood Glucose; Carbohydrate Metabolism; Disease Models, Animal; DNA Fragmentation; Glucocorticoids; Glycogen; Hydrocortisone; Immune System; Lipid Metabolism; Liver; Macrophages; Male; Nitric Oxide; Proteins; Rats; Spleen

Adrenomedullin (AM) is a potent vasodilating peptide and is involved in cardiovascular and renal disease. In the present study, we investigated the role of AM in cardiac and renal function in streptozotocin (STZ)-induced diabetic rats. A single tail-vein injection of adenoviral vectors harboring the human AM gene (Ad.CMV-AM) was administered to the rats 1-wk post-STZ treatment (65 mg/kg iv). Immunoreactive human AM was detected in the plasma and urine of STZ-diabetic rats treated with Ad.CMV-AM. Morphological and chemical examination showed that AM gene delivery significantly reduced glycogen accumulation within the hearts of STZ-diabetic rats. AM gene delivery improved cardiac function compared with STZ-diabetic rats injected with control virus, as observed by decreased left ventricular end-diastolic pressure, increased cardiac output, cardiac index, and heart rate. AM gene transfer significantly increased left ventricular long axis (11.69 +/- 0.46 vs. 10.31 +/- 0.70 mm, n = 10, P < 0.05) and rate of pressure rise and fall (+6,090.1 +/- 597.3 vs. +4,648.5 +/- 807.1 mmHg/s), (-4,902.6 +/- 644.2 vs. -3,915.5 +/- 805.8 mmHg/s, n = 11, P < 0.05). AM also significantly attenuated renal glycogen accumulation and tubular damage in STZ-diabetic rats as well as increased urinary cAMP and cGMP levels, along with increased cardiac cAMP and Akt phosphorylation. We also observed that delivery of the AM gene caused an increase in body weight along with phospho-Akt and membrane-bound GLUT4 levels in skeletal muscle. These results suggest that AM plays a protective role in hyperglycemia-induced glycogen accumulation and cardiac and renal dysfunction via Akt signal transduction pathways.

Topics: Adenoviridae; Adrenomedullin; Animals; Blood Glucose; Body Weight; Cyclic AMP; Cyclic GMP; Diabetes Mellitus, Experimental; Diabetic Nephropathies; Disease Models, Animal; Gene Expression; Genetic Therapy; Genetic Vectors; Glucose Transporter Type 4; Glycogen; Heart; Heart Function Tests; Humans; Kidney; Male; Monosaccharide Transport Proteins; Muscle Proteins; Muscle, Skeletal; Myocardium; Peptides; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Rats; Rats, Sprague-Dawley; Streptozocin; Ventricular Function, Left

We tested the hypothesis that an acute critical limitation in coronary flow reserve could rapidly recapitulate the physiological, molecular, and morphological phenotype of hibernating myocardium. Chronically instrumented swine were subjected to a partial occlusion to produce acute stunning, followed by reperfusion through a critical stenosis. Stenosis severity was adjusted serially so that hyperemic flow was severely reduced yet always higher than the preocclusion resting level. After 24 hours, resting left anterior descending coronary artery (LAD) wall thickening had decreased from 36.3+/-4.0% to 25.5+/-3.7% (P<0.05), whereas resting flow had remained normal (67+/-6 versus 67+/-8 mL/min, respectively). Although peak hyperemic flow exceeded the prestenotic value, resting flow (45+/-10 mL/min) and LAD wall thickening (17.0+/-5.0%) progressively decreased after 2 weeks, when physiological features of hibernating myocardium had developed. Regional reductions in sarcoplasmic reticulum proteins were present in hibernating myocardium but absent in stunned myocardium evaluated after 24 hours. Histological analysis showed an increase in connective tissue along with myolysis (myofibrillar loss per myocyte >10%) and increased glycogen typical of hibernating myocardium in the LAD region (33+/-3% of myocytes from animals with hibernating myocardium versus 15+/-4% of myocytes from sham-instrumented animals, P<0.05). Surprisingly, the frequency of myolysis was similar in normally perfused remote regions from animals with hibernating myocardium (32+/-7%). We conclude that the regional physiological and molecular characteristics of hibernating myocardium develop rapidly after a critical limitation in flow reserve. In contrast, the global nature of myolysis and increased glycogen content dissociate them from the intrinsic adaptations to ischemia. These may be related to chronic elevations in preload but appear unlikely to contribute to chronic contractile dysfunction.

Topics: Adaptation, Physiological; Animals; Calcium-Binding Proteins; Calcium-Transporting ATPases; Calsequestrin; Chronic Disease; Coronary Circulation; Coronary Stenosis; Disease Models, Animal; Disease Progression; Glycogen; Hemodynamics; Ischemic Preconditioning, Myocardial; Microspheres; Myocardial Contraction; Myocardial Ischemia; Myocardial Reperfusion; Myocardial Stunning; Myocardium; Myofibrils; RNA, Messenger; Sarcoplasmic Reticulum; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Swine

RSG is a member of the TZD group of drugs widely used in treatment of type 2 diabetes. The underlying mechanism of TZD action in insulin-sensitive tissues is not fully understood. In this study we show that 14-day RSG administration in a new rodent model of metabolic syndrome X, polydactylous rat strain (PD/Cub), substantially improves its lipid profile (serum TGs 4.20 +/- 0.23 vs 2.34 +/- 0.14 mmol/l, P < 0.0001; FFA 0.46 +/- 0.05 vs 0.33 +/- 0.02 mmol/l, P = 0.017), diminishes the liver TG depots (15.76 +/- 0.60 vs 8.44 +/- 0.55 micromol/g, P < 0.0001), serum insulin concentrations (1.10 +/- 0.08 vs 0.63 +/- 0.02 nmol/l, P < 0.0001) and promotes visceral adiposity (adiposity index 1.28 +/- 0.03 vs 1.85 +/- 0.07, P < 0.0001). No changes were observed in serum or liver concentrations of cholesterol. Concomitantly, both basal and insulin-stimulated glycogen synthesis in red-fibre type muscle (m. soleus) was enhanced, as well as glucose uptake into adipose tissue. However, glucose oxidation in soleus (basal and insulin-stimulated) remained unchanged. In consent with previously published data we suggest the current pharmacogenetic study as a further proof of substantial influence of genetic background on the physiological outcome of TZD therapy.

Topics: Adipose Tissue; Animals; Disease Models, Animal; Glucose; Glucose Tolerance Test; Glycogen; Hypoglycemic Agents; Insulin; Insulin Resistance; Lipids; Male; Metabolic Syndrome; Rats; Rats, Inbred Strains; Rosiglitazone; Thiazoles; Thiazolidinediones

Pompe disease is a lysosomal storage disease caused by the absence of acid alpha-1,4 glucosidase (GAA). The pathophysiology of Pompe disease includes generalized myopathy of both cardiac and skeletal muscle. We sought to use recombinant adeno-associated virus (rAAV) vectors to deliver functional GAA genes in vitro and in vivo. Myotubes and fibroblasts from Pompe patients were transduced in vitro with rAAV2-GAA. At 14 days postinfection, GAA activities were at least fourfold higher than in their respective untransduced controls, with a 10-fold increase observed in GAA-deficient myotubes. BALB/c and Gaa(-/-) mice were also treated with rAAV vectors. Persistent expression of vector-derived human GAA was observed in BALB/c mice up to 6 months after treatment. In Gaa(-/-) mice, intramuscular and intramyocardial delivery of rAAV2-Gaa (carrying the mouse Gaa cDNA) resulted in near-normal enzyme activities. Skeletal muscle contractility was partially restored in the soleus muscles of treated Gaa(-/-) mice, indicating the potential for vector-mediated restoration of both enzymatic activity and muscle function. Furthermore, intramuscular treatment with a recombinant AAV serotype 1 vector (rAAV1-Gaa) led to nearly eight times normal enzymatic activity in Gaa(-/-) mice, with concomitant glycogen clearance as assessed in vitro and by proton magnetic resonance spectroscopy.

Topics: alpha-Glucosidases; Animals; Cardiovascular Diseases; Dependovirus; Disease Models, Animal; Fibroblasts; Gene Expression Regulation; Genetic Therapy; Genetic Vectors; Glycogen; Glycogen Storage Disease Type II; Homozygote; Humans; Immunoenzyme Techniques; Infant; Lysosomal Storage Diseases; Mice; Mice, Inbred BALB C; Mice, Knockout; Muscle, Skeletal; Myocardium; Transduction, Genetic

The p90 ribosomal S6 kinase (RSK), a cytosolic substrate for the extracellular signal-regulated kinase (ERK), is involved in transcriptional regulation, and one isoform (RSK2) has been implicated in the activation of glycogen synthase by insulin. To determine RSK2 function in vivo, mice lacking a functional rsk2 gene were generated and studied in response to insulin and exercise, two potent stimulators of the ERK cascade in skeletal muscle. RSK2 knockout (KO) mice weigh 10% less and are 14% shorter than wild-type (WT) mice. They also have impaired learning and coordination. Hindlimb skeletal muscles were obtained from mice 10, 15, or 30 min after insulin injection or immediately after strenuous treadmill exercise for 60 min. While insulin and exercise significantly increased ERK phosphorylation in skeletal muscle from both WT and KO mice, the increases were twofold greater in the KO animals. This occurred despite 27% lower ERK2 protein expression in skeletal muscle of KO mice. KO mice had 18% less muscle glycogen in the fasted basal state, and insulin increased glycogen synthase activity more in KO than WT mice. The enhanced insulin-stimulated increases in ERK and glycogen synthase activities in KO mice were not associated with higher insulin receptor or with IRS1 tyrosine phosphorylation or with IRS1 binding to phosphatidylinositol 3-kinase. However, insulin-stimulated serine phosphorylation of Akt was significantly higher in the KO animals. c-fos mRNA was increased similarly in muscle from WT and KO mice in response to insulin (2. 5-fold) and exercise (15-fold). In conclusion, RSK2 likely plays a major role in feedback inhibition of the ERK pathway in skeletal muscle. Furthermore, RSK2 is not required for activation of muscle glycogen synthase by insulin but may indirectly modulate muscle glycogen synthase activity and/or glycogen content by other mechanisms, possibly through regulation of Akt. RSK2 knockout mice may be a good animal model for the study of Coffin-Lowry syndrome.

Topics: Animals; Body Weight; Cognition; Disease Models, Animal; Enzyme Activation; Feedback; Gene Deletion; Gene Expression Regulation, Enzymologic; Gene Targeting; Glycogen; Glycogen Synthase; Insulin; MAP Kinase Signaling System; Mice; Mice, Knockout; Mitogen-Activated Protein Kinases; Muscle, Skeletal; Phosphorylation; Physical Conditioning, Animal; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Ribosomal Protein S6 Kinases

In order to explore the possible effects of physical therapy interventions on people with hypertension, we evaluated the effects of aerobic exercise training on myocardial energy metabolism in an animal model of hypertension.. We used 36 female spontaneously hypertensive rats (rats with genetically induced hypertension) and 12 normotensive Wistar-Kyoto rats.. The normotensive rats were sedentary and formed the CONsed group. The spontaneously hypertensive rats were randomly divided into 3 experimental groups (12 rats per group). Hypertensive rats that were sedentary formed the HTNsed group, those that received 8 weeks of exercise training formed the HTNx8 group, and those that received 16 weeks of exercise training formed the HTNx16 group. We measured systolic blood pressure, heart wet weight, maximal activities of cardiac energy metabolism enzymes, glucose transporter content, and total concentrations of protein, glycogen, and triglyceride.. Systolic blood pressure was greater than 200 mm Hg in the CONsed group at the time of testing. Exercise training modestly (approximately 11-18 mm Hg) lowered blood pressure in the HTNx8 and HTNx16 groups. Fatty acid enzyme activity was greater in the CONsed group than in HTNsed and HTNx8 groups, but activity was roughly equivalent between the CONsed group and the HTNx16 group. Glucose enzyme activity was greater in the HTNx16 group than in the CONsed group and HTNsed group. Intracellular glycogen concentration was greater in the HTNx8 group than in HTNsed group.. Results of this study suggest that aerobic exercises may help to normalize cardiac energy metabolism in mammals with hypertension.

Topics: Animals; Blood Pressure; Carnitine O-Palmitoyltransferase; Citrate (si)-Synthase; Disease Models, Animal; Energy Metabolism; Female; Glycogen; Glycolysis; Hexokinase; Hypertension; Myocardium; Physical Conditioning, Animal; Physical Therapy Modalities; Random Allocation; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Systole

N-methyl-1-deoxynojirimycin (NMDN), an a-glucosidase inhibitor, reduces myocardial infarct size by reducing the glycogenolytic rate through inhibition of the alpha-1,6-glucosidase of glycogen-debranching enzyme in the heart, in addition to possessing an antihyperglycemic action by blocking alpha-1,4-glucosidase in the intestine. Ischemic preconditioning (PC), which markedly reduces the size of the myocardial infarct, is known to reduce the activity of phosphorylase and reduce the glycogenolytic rate. Therefore, it was hypothesized that a combination of pharmacological inhibition of glycogenolysis by an alpha-1,6-glucosidase inhibitor, NMDN, and PC could markedly reduce myocardial infarct size more than NMDN or PC alone. Japanese white rabbits without collateral circulation were subjected to a 30-min coronary occlusion followed by 48-h reperfusion. The infarct sizes as a percentage of area at risk were significantly reduced by pre-ischemic treatment with either 100mg/kg of NMDN or PC of 5 min ischemia and 5 min reperfusion alone (15.9+/-2.0%, n=8, and 10.3+/-1.2%, n=8, respectively) as compared with the control (43.9+/-2.2%, n=8). However, the combination of 100mg/kg of NMDN and PC significantly reduced the infarct size (4.9+/-1.2, n=8) compared with NMDN or PC alone. Another 40 rabbits, also given 100mg of NMDN, PC, NMDN+PC or saline before ischemia (n=10 in each group), were killed for biochemical analysis after 30 min of ischemia. NMDN and PC preserved the glycogen content and attenuated the lactate accumulation, respectively, as compared with the control. However, the combination of NMDN and PC preserved significantly more glycogen and significantly reduced lactate accumulation than either NMDN or PC alone. The combination of NMDN and PC markedly reduced the myocardial infarct size more than either process alone. The marked preservation of glycogen and marked attenuation of lactate accumulation by the combination of NMDN and PC suggest that the mechanism for this effect of NMDN+PC is related to the inhibition of glycogenolysis.

Topics: 1-Deoxynojirimycin; Animals; Combined Modality Therapy; Disease Models, Animal; Enzyme Inhibitors; Glycogen; Glycoside Hydrolase Inhibitors; Heart Ventricles; Ischemia; Ischemic Preconditioning, Myocardial; Lactic Acid; Myocardial Infarction; Rabbits

Physical exercise is frequently recommended for the treatment of type 2 diabetes, whether as primary therapy with diet modification or as an adjunct to drug therapy. We hypothesized that mild exercise would enhance the glucose-lowering effects of 2 oral antihyperglycemic drugs, metformin and acarbose, in an animal model of type 2 diabetes. Eight-week-old male C57BL/Ks (db/db) mice were sorted into control and exercise groups and dosed daily for 4 weeks with vehicle, metformin (150 mg/kg/d), or acarbose (40 mg/kg/d). Exercise consisted of swimming (initially 5 min/d and ultimately 1 h/d for the last 2 weeks). Exercise, metformin, and acarbose independently reduced serum glucose concentrations 15% to 25% compared with the respective controls (P <.0001), but the effect on glucose concentration of combining drug therapy with exercise was no greater than the sum of the individual effects. Exercise training independently increased muscle glycogen (30%; P <.05) and liver glycogen (250%; P <.05) levels and slightly reduced serum high-density lipoprotein cholesterol (-8%; P <.05), whereas drug treatment had no effect on these variables. In addition, exercise but not drug treatment prevented the approximately 30% decline in serum insulin concentrations that occurred in the control animals (P <.05). Twenty-four hours after the last drug or exercise treatment, oral glucose tolerance and hemoglobin A1c were not significantly different between groups. Treatment also did not greatly affect triglyceride, glycerol, or total cholesterol concentrations. In conclusion, exercise and drug therapy independently decreased serum glucose in db/db mice, and these effects did not appear to be synergistic. In addition, exercise training maintained serum insulin concentrations and increased tissue glycogen storage. These results suggest that exercise has the potential to add to the efficacy of oral antihyperglycemic drugs.

Topics: Acarbose; Animals; Blood Glucose; Body Weight; Diabetes Mellitus, Type 2; Disease Models, Animal; Eating; Glucose Tolerance Test; Glycated Hemoglobin; Glycogen; Hypoglycemic Agents; Insulin; Lipids; Liver; Male; Metformin; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Muscle, Skeletal; Physical Exertion; Swimming; Treatment Outcome

Topics: Analysis of Variance; Animals; Body Weight; Diabetes Mellitus, Experimental; Disease Models, Animal; Glycogen; Heart; Hemodynamics; Humans; Isoproterenol; L-Lactate Dehydrogenase; Lactates; Male; Myocardial Infarction; Myocardial Ischemia; Myocardium; Necrosis; Organ Size; Rats; Rats, Wistar

Injection of excitotoxins, such as quinolinic acid (QA), into the striatum has been extensively used as an experimental model of Huntington's disease, while injection of 6-hydroxydopamine (6-OHDA) into the dopaminergic nigrostriatal pathway provides a well established model of Parkinson's disease. In the present study, we have examined the metabolic changes induced by an intrastriatal injection of QA or 6-OHDA using histochemical staining for the metabolic markers cytochrome oxidase (COx) and active glycogene phosphorylase (GPa). Intrastriatal injection of QA produced major changes in COx (decrease of staining) and GPa (increase of staining, except in the core of the lesion where the staining was virtually absent) histochemistry at the level of the striatum and of most of the other basal ganglia nuclei. Although attenuated over time, these changes persisted up to one year after the lesion. On the contrary, after the intrastriatal injection of 6-OHDA (which induces only a partial lesion of the nigrostriatal pathway), we did not observe any remarkable changes in COx or GPa staining. This study illustrates the discrepancies between the morphological changes and metabolic changes that are induced when using these experimental models of neurodegenerative disorders.

Topics: Animals; Autoradiography; Benzazepines; Biomarkers; Corpus Striatum; Disease Models, Animal; Dopamine Antagonists; Dopamine Uptake Inhibitors; Electron Transport Complex IV; Glycogen; Huntington Disease; Male; Mazindol; Microinjections; Nerve Degeneration; Oxidopamine; Parkinson Disease; Phosphorylase a; Quinolinic Acid; Radioligand Assay; Rats; Rats, Sprague-Dawley; Receptors, Dopamine; Sympatholytics; Tritium

The aim of the present study was to estimate whether a single bout of exhaustive exercise influences the glycogen and triglyceride (TG) content in red and white gastrocnemius muscle and in the liver of rats with experimental type 2 diabetes. Experiments were carried out on male Wistar rats fed from 8 to 11 weeks of age with isocaloric standard or high-fat diet (HFD) with a previous injection of low-dose of streptozotocin (STZ) or vehicle at 2 days of age (I, control group; II, HFD; III, STZ; IV, STZ + HFD). Group IV (STZ + HFD) represents a model of type 2 diabetes. Basal liver glycogen was markedly lower in all the studied groups compared to controls. Glycogen concentration after exercise fell significantly in the examined tissues in all groups in comparison to basal conditions. A significant TG accumulation in examined tissues was observed in all the studied groups in comparison to controls. Exercise decreased tissue TG content in all the groups, but it remained significantly higher in the experimental groups vs. control. We conclude that in this model of type 2 diabetes, a single bout of exercise reveals defective utilization of tissue carbohydrates and lipids.

Topics: Animals; Blood Glucose; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Disease Models, Animal; Glycogen; Insulin; Liver; Male; Muscle Fibers, Fast-Twitch; Muscle, Skeletal; Physical Exertion; Rats; Rats, Wistar; Triglycerides

Functionally useful reanimation of paralyzed limbs generally requires reliable, finely graded control of muscle recruitment and force with minimal fatigue. We used force and electromyographic (EMG) recordings in combination with myofibrillar adenosine triphosphatase activity and glycogen depletion analysis to investigate the recruitment properties of intramuscular (IM) and nerve cuff (NC) stimulating electrodes implanted acutely or chronically in cat hindlimbs. Overall, 32 muscles were submaximally stimulated with current intensities producing approximately 20% of maximal twitch force using 330 ms trains of pulses at 20 and 40 pps. Both the glycogen-depletion and fatigue-test results were found to be difficult to interpret because NC stimulation resulted in surprisingly unstable recruitment during such trains. Fluctuations of force and M-waves within trains of identical stimuli were significantly greater for NC than for IM stimulation. NC stimulation produced much steeper recruitment curves and a reduced tetanus/twitch ratio compared to IM stimulation. IM stimulation produced more reliable and less fatigable recruitment of a mix of motor unit types that tended to be localized in neuromuscular compartments containing, or adjacent to, the IM electrode. We hypothesize that trains of submaximal stimulation applied through NC electrodes resulted in fluctuating recruitment because this electrode configuration magnifies the effects of refractoriness and small changes in axonal excitability during pulse trains.

Topics: Acute Disease; Adenosine Triphosphate; Animals; Cats; Chronic Disease; Disease Models, Animal; Electric Stimulation Therapy; Electrodes, Implanted; Electromyography; Equipment Design; Female; Glycogen; Hindlimb; Male; Materials Testing; Muscle Fatigue; Muscle, Skeletal; Myofibrils; Paralysis; Recruitment, Neurophysiological; Sciatic Nerve

We sought to determine whether improving coupling between glucose oxidation and glycolysis by stimulating glucose oxidation during reperfusion enhances postischemic recovery of hypertrophied hearts.. Low rates of glucose oxidation and high glycolytic rates are associated with greater postischemic dysfunction of hypertrophied as compared with nonhypertrophied hearts.. Heart function, glycolysis and glucose oxidation were measured in isolated working control and hypertrophied rat hearts for 30 min before 20 min of global, no-flow ischemia and during 60 min of reperfusion. Selected control and hypertrophied hearts received 1.0 mmol/liter dichloroacetate (DCA), an activator of pyruvate dehydrogenase, at the time of reperfusion to stimulate glucose oxidation.. In the absence of DCA, glycolysis was higher and glucose oxidation and recovery of function were lower in hypertrophied hearts than in control hearts during reperfusion. Dichloroacetate stimulated glucose oxidation during reperfusion approximately twofold in both groups, while significantly reducing glycolysis in hypertrophied hearts. It also improved function of both hypertrophied and control hearts. In the presence of DCA, recovery of function of hypertrophied hearts was comparable to or better than that of untreated control hearts.. Dichloroacetate, given at the time of reperfusion, normalizes postischemic function of hypertrophied rat hearts and improves coupling between glucose oxidation and glycolysis by increasing glucose oxidation and decreasing glycolysis. These findings support the hypothesis that low glucose oxidation rates and high glycolytic rates contribute to the exaggerated postischemic dysfunction of hypertrophied hearts.

Topics: Animals; Cardiomegaly; Dichloroacetic Acid; Disease Models, Animal; Glucose; Glycogen; Glycolysis; In Vitro Techniques; Male; Myocardial Reperfusion Injury; Myocardium; Oxidation-Reduction; Pyruvate Dehydrogenase Complex; Rats; Rats, Sprague-Dawley; Ventricular Function

Present animal models used to emulate type 2 diabetes may not accurately reflect the metabolic changes that occur in humans.. The purpose of this research was to evaluate diets reported to induce insulin resistance and impaired glucose metabolism in rats as a potentially useful model for studying type 2 diabetes.. Three groups of male Sprague Dawley rats (n=7) were fed either a control diet, based on AIN recommendations (53% cornstarch, 10% sucrose and 7% soybean oil), a high fat diet (25% soybean oil, 35% cornstarch) or a high fructose diet (53% fructose, 10% sucrose) for a 3 month period. Glucose tolerance tests were carried out in week 3 and week 9 of the experiment. At the termination of the experiment, serum insulin, glucose, cholesterol and triacylglycerols were measured. Glucose incorporation into glycogen and glycogen synthase activity were measured in soleus muscles.. Similar weight gain was observed for all three groups of rats. Glucose tolerance curves and fasting glucose levels were not significantly different at any time point in the experiment. Insulin levels were unchanged for the controls (171+/-21 pM), high fructose (164+/-16 pM) and high fat (181+/-30 pM) diets. Fasting serum triacylglycerols and cholesterol levels were not significantly elevated by dietary treatment. In soleus muscles, rats on all three diets had a significant increase in glycogen synthesis in response to insulin, but synthesis was similar in all three groups. Glycogen synthase activity was also not significantly affected by long-term dietary intervention.. In this study, healthy Sprague Dawley rats fed high fat or high fructose diets for 3 months adapted to the nutritional intervention without developing classical signs of insulin resistance and impaired glucose tolerance.

Topics: Adaptation, Biological; Animals; Cholesterol; Diabetes Mellitus, Type 2; Dietary Carbohydrates; Dietary Fats; Disease Models, Animal; Fructose; Glucose; Glucose Tolerance Test; Glycogen; Glycogen Synthase; Insulin; Insulin Resistance; Male; Muscles; Rats; Rats, Sprague-Dawley; Time Factors; Triglycerides

Ewing's sarcoma shows a strong tendency to metastasize to the lungs or the skeleton, or both. A peculiar feature of the secondary involvement of bone with this tumor is that it may also appear in the absence of clinically evident lung metastases, both at clinical presentation and during the course of the disease. Although osseous metastases are critically relevant for prognosis, the pathogenesis of this peculiar feature of Ewing's sarcoma is poorly understood, partly due to the lack of appropriate experimental in vivo models. We show that the intravenous injection of TC-71 Ewing's sarcoma cells into athymic 4-5-week-old Crl/nu/nu (CD1) BR mice reproducibly colonizes specific sites of the skeleton in addition to the lungs and lymph nodes. The distribution and the morphologic appearance of these experimental bone metastases mimic the pattern of skeletal involvement observed in humans. This experimental model of bone metastasis of Ewing's sarcoma may be the basis for future studies aimed at understanding the pathophysiology and treatment of Ewing's sarcoma.

Topics: 12E7 Antigen; Animals; Antigens, CD; Bone Neoplasms; Cell Adhesion Molecules; Disease Models, Animal; Female; Glycogen; Integrins; Lung Neoplasms; Matrix Metalloproteinases; Mice; Mice, Nude; Neoplasm Metastasis; Receptors, Growth Factor; Sarcoma, Ewing; Tissue Inhibitor of Metalloproteinase-1; Tissue Inhibitor of Metalloproteinase-2; Tumor Cells, Cultured

To examine the role of the adenosine A1 receptor in glucose regulation in the absence of insulin, the present study investigated the changes of plasma glucose in male streptozotocin-induced diabetic rats (STZ-diabetic rats) using dipyridamole to increase endogenous adenosine and N6-cyclopentyladenosine (CPA) to activate the adenosine A1 receptor. Intravenous injections of dipyridamole or CPA induced a dose-dependent decrease of plasma glucose in fasting STZ-diabetic rats. Plasma glucose lowering action of dipyridamole, like that of CPA, was inhibited in a dose-dependent manner by pre-treatment with 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) or 8-(p-sulfophenyl)theophylline (8-SPT) at which block the adenosine A1 receptors. Action of the adenosine A1 receptors can thus be considered. In isolated skeletal muscle, CPA enhanced the glucose uptake in a concentration-dependent manner. Blockade of this action by DPCPX and 8-SPT again supported the mediation of the adenosine A1 receptor. Also, CPA produced an increase of glycogen synthesis in isolated soleus muscle. Moreover, CPA decreased plasma triglyceride and cholesterol levels significantly in STZ-diabetic rats. These results suggest that activation of adenosine A1 receptors can increase glucose utilization in peripheral tissues by increasing tissue uptake and glycogen synthesis to lower plasma glucose in rats lacking insulin.

Topics: Adenosine; Animals; Blood Glucose; Cholesterol; Diabetes Mellitus, Experimental; Dipyridamole; Disease Models, Animal; Dose-Response Relationship, Drug; Glucose; Glycogen; Hypoglycemic Agents; Insulin; Male; Muscle, Skeletal; Purinergic P1 Receptor Antagonists; Rats; Rats, Wistar; Receptors, Purinergic P1; Streptozocin; Theophylline; Triglycerides; Xanthines

We examined whether pharmacological inhibition of glycogenolysis by N-methyl-1-deoxynojirimycin (MOR-14), a new compound which reduces the glycogenolytic rate by inhibiting the alpha-1,6-glucosidase activity of the glycogen-debranching enzyme, can protect the heart against postischemic left ventricular dysfunction. The hearts of male Sprague-Dawley rats were excised, and perfused on a Langendorff apparatus with Krebs-Henseleit solution with a gas mixture of 95% O2 and 5% CO2. The hearts were paced at 320 beats/min except during the ischemia. Left ventricular developed pressure (LVDP, mmHg), +/-dP/dt (mmHg/s), and coronary flow (ml/min) were continuously monitored. All hearts were perfused for a total of 120 min including a 30-min preischemic period followed by a 30-min episode of global ischemia and 60 min reperfusion. with or without 0.5 or 2 mM of MOR-14 during the 30-min preischemic period or the first 30 min of reperfusion. In another series of experiments, the myocardial content of glycogen and lactate was measured during the 30-min episode of ischemia in groups treated with and without 2mM of MOR-14. Preischemic but not postischemic treatment with MOR-14 significantly improved LVDP and +/-dP/dt without altering coronary flow during reperfusion in a dose-dependent manner. MOR-14 significantly preserved the glycogen content and significantly attenuated the lactate accumulation during the 30-min episode of ischemia. Preischemic treatment with MOR-14 is protective against postischemic left ventricular dysfunction through the inhibition of glycogenolysis in the isolated rat heart.

Topics: 1-Deoxynojirimycin; Adenosine Triphosphate; Animals; Blood Flow Velocity; Disease Models, Animal; Enzyme Inhibitors; Glycogen; Glycoside Hydrolase Inhibitors; Heart; Lactic Acid; Male; Myocardial Ischemia; Myocardial Reperfusion; Rats; Rats, Sprague-Dawley; Time Factors; Ventricular Dysfunction, Left

Several recent studies have suggested that nitric oxide (NO) derived from the inducible isoform of NO synthase (NOS) may act as an endogenous modulator of the inflammatory response by inhibiting adhesion of leukocytes to endothelial cells in vitro. Few studies have addressed specifically the role of iNOS in regulating leukocyte recruitment in vivo in a model of acute inflammation. Thus, the objective of this study was to assess the role of iNOS in modulating neutrophil (PMN) extravasation in an oyster glycogen-induced model of acute peritonitis in rats. Data obtained in the present study demonstrates that injection (IP) of oyster glycogen induces massive and selective PMN recruitment into the peritoneal cavity of rats at 6 hrs following OG administration. These extravasated cells were found to contain significant amounts of iNOS protein as assessed by Western blot analysis. Treatment of rats with the selective iNOS inhibitor L-iminoethyl-lysine (L-NIL) dramatically reduced NO levels in lavage fluid as measured by decreases in nitrate and nitrite concentrations without significantly affecting iNOS protein levels. Although L-NIL inhibited NO production by >70%, it did not alter oyster glycogen-induced PMN recruitment when compared to vehicle-treated rats. We conclude that PMN-associated, iNOS-derived NO does not play an important role in modulating extravasation of these leukocytes in this model of acute inflammation.

Topics: Acute Disease; Animals; Ascitic Fluid; Blotting, Western; Cell Movement; Disease Models, Animal; Enzyme Induction; Female; Glycogen; Inflammation; Lysine; Neutrophils; Nitrates; Nitric Oxide; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Nitrites; Ostreidae; Peritonitis; Rats; Rats, Inbred Lew

The relevance of regional LV myocardial ischemia/reperfusion induced by temporary left anterior descending (LAD) coronary artery occlusion during minimally invasive direct coronary artery bypass (MIDCAB) grafting is controversial. The purpose of our study was (1) to determine the impact of conventional LAD occlusion during left internal thoracic artery (LITA)-LAD anastomosis on regional LV myocardial ischemia and function, and (2) to evaluate if intra-LAD shunt insertion during LITA-LAD anastomosis prevents potential regional LV ischemia and dysfunction in a pig model.. In 20 anesthetized, mechanically ventilated pigs we performed LITA-LAD anastomosis on the beating heart without cardiopulmonary bypass during either 15 min LAD occlusion (occlusion-group; n = 10) or 15 min intra-LAD shunt insertion to maintain blood supply to the myocardium beyond the anastomosis (shunt-group; n = 10). Besides standard hemodynamics we determined the global and regional LV wall motion score index (WMSI) using epimyocardial echocardiography. To quantitate structural myocardial alteration we determined the inducible heat-shock protein-70 (HSP-70) in LV anterior wall myocardial biopsies. Data were recorded at baseline, at 15 min of LAD occlusion or shunt insertion, respectively, and at 30 min of reperfusion. At the end of the experiments we determined myocardial adenine nucleotide (ATP, ADP, AMP) and glycogen content.. In both groups WMSI was not significantly different at 15 min LAD occlusion or shunt insertion, respectively, as compared to baseline. However, at 30 min reperfusion both global and regional WMSI demonstrated significant LV dysfunction in the occlusion-group, whereas LV function in the shunt-group remained normal. This was associated with higher myocardial HSP-70 expression in the occlusion-group (P < 0.05). Myocardial adenine nucleotide and glycogen contents were significantly better preserved in the shunt-group.. Our data show that in a porcine MIDCAB model 15 min LAD occlusion and 30 min reperfusion result in significant myocardial stunning. In contrast, maintenance of LAD perfusion using intracoronary shunt insertion minimizes ischemia/reperfusion injury and prevents regional LV dysfunction. Although our experiments were conducted in healthy pig hearts absent from coronary artery disease, similar results may--at least partially--be expected in humans, and thus, intracoronary shunts could be a useful tool for myocardial protection during 'off-pump revascularization'.

Topics: Adenine Nucleotides; Anastomosis, Surgical; Animals; Blood Vessel Prosthesis Implantation; Coronary Artery Bypass; Coronary Disease; Disease Models, Animal; Echocardiography; Female; Glycogen; Hemodynamics; HSP70 Heat-Shock Proteins; Male; Minimally Invasive Surgical Procedures; Myocardial Stunning; Myocardium; Swine

"Autoresuscitation" (AR) is the spontaneous recovery from hypoxic apnea by gasping. We examined aspects of heart function in two situations: 1) the maturationally acquired failure of AR that is characteristic of SWR, but not BALB/c, weanling mice and 2) AR failure in BALB/c mice induced by repeated exposures to anoxia. We determined maturational changes in heart and liver glycogen. Unlike liver glycogen levels, heart glycogen levels in SWR mice differed from those in BALB/c mice. They were consistently much lower throughout maturation and reached a nadir during the brief period when SWR weanling mice are vulnerable to AR failure. Also, rate of cardiac glycogen utilization in vulnerable SWR mice was lower than that of same-aged BALB/c mice and was nil during the latter one-half of the gasping stage when heart function is critical for AR success. Therefore, because glycogen utilization reflects cardiac work, heart failure could explain AR failure in SWR weanlings. Additionally, the increase in hypoxic heart rate that occurs with maturation is developmentally delayed in SWR mice, and this may contribute to their AR failure. Cardiac glycogen was not fully depleted in BALB/c mice during repeated anoxic exposures, indicating other reasons for AR failure. We view these findings as a potential model for the age-related peak in incidence of sudden infant death syndrome.

Topics: Age Factors; Animals; Apnea; Disease Models, Animal; Glycogen; Heart Rate; Humans; Hypoxia; Infant; Liver Glycogen; Mice; Mice, Inbred BALB C; Myocardium; Resuscitation; Sudden Infant Death

Glycogen storage disease type II (GSDII; Pompe disease), caused by inherited deficiency of acid alpha-glucosidase, is a lysosomal disorder affecting heart and skeletal muscles. A mouse model of this disease was obtained by targeted disruption of the murine acid alpha-glucosidase gene (Gaa) in embryonic stem cells. Homozygous knockout mice (Gaa -/-) lack Gaa mRNA and have a virtually complete acid alpha-glucosidase deficiency. Glycogen-containing lysosomes are detected soon after birth in liver, heart and skeletal muscle cells. By 13 weeks of age, large focal deposits of glycogen have formed. Vacuolar spaces stain positive for acid phosphatase as a sign of lysosomal pathology. Both male and female knockout mice are fertile and can be intercrossed to produce progeny. The first born knockout mice are at present 9 months old. Overt clinical symptoms are still absent, but the heart is typically enlarged and the electrocardiogram is abnormal. The mouse model will help greatly to understand the pathogenic mechanism of GSDII and is a valuable instrument to explore the efficacy of different therapeutic interventions.

Topics: alpha-Glucosidases; Animals; Cardiomegaly; Disease Models, Animal; Female; Glycogen; Glycogen Storage Disease Type II; Male; Mice; Mice, Knockout

Although cardioplegic protection of the hypertrophied heart remains a clinical challenge, we have previously observed enhanced recovery in rat hearts with pressure-overload hypertrophy induced by aortic banding. We investigated whether this unexpected result is found in other models of hypertrophy.. Hearts with hypertrophy induced by aortic banding or administration of desoxycorticosterone acetate were each compared with age-matched sham-operated and nonoperated controls. Spontaneously hypertensive rats and Wistar-Kyoto controls were also compared. We evaluated left ventricular isomyosin distribution by gel electrophoresis and recovery of isolated working rat hearts arrested at 8 degrees C for 2 hours.. The percentage of V3 isomyosin in hearts with hypertrophy from aortic banding or administration of desoxycorticosterone acetate was increased compared with the control groups. Recovery of aortic flow in all three groups of hypertrophied hearts was at least as good or better than their respective controls. There were no significant differences in ATP or glycogen between hypertrophied and control hearts before or after arrest.. Enhanced recovery of hypertrophied hearts is not specific to a single model. This level of recovery may be supported by induction of a "fetal genetic program," exemplified in the rat by the shift in isomyosin from predominantly V1 to the more efficient V3 isoform, which occurs in pressure-overloaded hearts.

Topics: Adenosine Triphosphate; Animals; Aorta, Abdominal; Cardioplegic Solutions; Chromatography, High Pressure Liquid; Desoxycorticosterone; Disease Models, Animal; Electrophoresis, Polyacrylamide Gel; Glycogen; Heart; Heart Arrest, Induced; Hemodynamics; Hypertrophy, Left Ventricular; In Vitro Techniques; Ligation; Myocardium; Myosins; Nephrectomy; Phosphocreatine; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Rats, Sprague-Dawley

Acid alpha-glucosidase (GAA) deficiency causes Pompe disease, a lethal lysosomal glycogen storage disease for which no effective treatment currently exists. We investigated the endocytic process in deficient cells of human recombinant GAA produced in Chinese hamster ovary cells, and the potential of GAA-deficient Japanese acid maltase-deficient quail as a model for evaluating the enzyme replacement therapy for Pompe disease. After 24-h incubation with a single dose of recombinant enzyme, intracellular GAA and glycogen levels in deficient human fibroblasts were normalized, and this correction lasted for 7 d. The 110-kD precursor recombinant enzyme was processed to the 76-kD mature form within 24 h after uptake. Intracellular GAA levels in deficient quail fibroblasts and myoblasts were similarly corrected to their average normal levels within 24 h. Differences existed in the efficiency of endocytosis among subfractions of the enzyme, and among different cell types. Fractions with a larger proportion of precursor GAA were endocytosed more efficiently. Quail fibroblasts required a higher dose, 4200 nmol.h-1.mL-1 to normalize intracellular GAA levels than human fibroblasts, 1290 nmol.h-1.mL-1, whereas primary quail myoblasts required 2800 nmol.h-1.mL-1. In all three cell lines, the endocytosed enzyme localized to the lysosomes on immunofluorescence staining, and the endocytosis was inhibited by mannose 6-phosphate (Man-6-P) added to the culture medium. Despite structural differences in Man-6-P receptors between birds and mammals, these studies illustrate that Man-6-P receptor mediated endocytosis is present in quail muscle cells, and demonstrate the potential of acid maltase-deficient quail to test receptor mediated enzyme replacement therapy for Pompe disease.

Topics: alpha-Glucosidases; Animals; Biological Transport, Active; Cells, Cultured; CHO Cells; Cricetinae; Disease Models, Animal; Endocytosis; Fibroblasts; Glucan 1,4-alpha-Glucosidase; Glycogen; Glycogen Storage Disease Type II; Humans; Kinetics; Muscles; Quail; Receptor, IGF Type 2; Recombinant Proteins

Topics: Animals; Diet; Disease Models, Animal; Female; Glycogen; Lipids; Male; Proteins; Rats; Rats, Wistar; Skin; Skin Physiological Phenomena

The authors previously demonstrated, in a large-animal intracerebral hemorrhage (ICH) model, that markedly edematous ("translucent") white matter regions (> 10% increases in water contents) containing high levels of clot-derived plasma proteins rapidly develop adjacent to hematomas. The goal of the present study was to determine the concentrations of high-energy phosphate, carbohydrate substrate, and lactate in these and other perihematomal white and gray matter regions during the early hours following experimental ICH.. The authors infused autologous blood (1.7 ml) into frontal lobe white matter in a physiologically controlled model in pigs (weighing approximately 7 kg each) and froze their brains in situ at 1, 3, 5, or 8 hours postinfusion. Adenosine triphosphate (ATP), phosphocreatine (PCr), glycogen, glucose, lactate, and water contents were then measured in white and gray matter located ipsi- and contralateral to the hematomas, and metabolite concentrations in edematous brain regions were corrected for dilution. In markedly edematous white matter, glycogen and glucose concentrations increased two- to fivefold compared with control during 8 hours postinfusion. Similarly, PCr levels increased several-fold by 5 hours, whereas, except for a moderate decrease at 1 hour, ATP remained unchanged. Lactate was markedly increased (approximately 20 micromol/g) at all times. In gyral gray matter overlying the hematoma, water contents and glycogen levels were significantly increased at 5 and 8 hours, whereas lactate levels were increased two- to fourfold at all times.. These results, which demonstrate normal to increased high-energy phosphate and carbohydrate substrate concentrations in edematous perihematomal regions during the early hours following ICH, are qualitatively similar to findings in other brain injury models in which a reduction in metabolic rate develops. Because an energy deficit is not present, lactate accumulation in edematous white matter is not caused by stimulated anaerobic glycolysis. Instead, because glutamate concentrations in the blood entering the brain's extracellular space during ICH are several-fold higher than normal levels, the authors speculate, on the basis of work reported by Pellerin and Magistretti, that glutamate uptake by astrocytes leads to enhanced aerobic glycolysis and lactate is generated at a rate that exceeds utilization.

Topics: Adenosine Triphosphate; Aerobiosis; Animals; Astrocytes; Blood Proteins; Body Water; Brain Edema; Brain Injuries; Cerebral Hemorrhage; Disease Models, Animal; Energy Metabolism; Extracellular Space; Frontal Lobe; Glucose; Glutamates; Glycogen; Glycolysis; Hematoma; Lactates; Phosphocreatine; Swine; Time Factors

Acid maltase deficiency (AMD) causes a lysosomal glycogenosis inherited as an autosomal recessive trait. The infantile type of AMD (Pompe disease) leads to early death due to severe dysfunction of cardiac and respiratory muscles and no effective therapy is available. Replication-defective adenovirus vectors offer a promising tool for in vivo gene delivery and gene therapy. We constructed a recombinant adenovirus containing the human acid maltase (AM) cDNA downstream of the CAG promoter, composed of modified chicken beta-actin promoter and CMV IE enhancer (AxCANAM). Japanese quail with AMD was used for this study as an animal model for human AMD. When cultured fibroblasts from AMD quail were infected with AxCANAM, AM activity in the cells increased in proportion to the multiplicity of infection (MOI). When AxCANAM (4.5 x 10(8) PFU) was injected into unilateral superficial pectoral muscle of AMD quail, PAS staining showed that glycogenosomes disappeared and stainability of acid phosphatase was reduced in the injected area as compared with the contralateral muscle of the same birds. Biochemically, AM activity increased and glycogen content decreased in the injected muscle. Western blot analysis showed that AMD quail muscle injected with AxCANAM expressed human AM protein processed to active forms. These results suggest that the human AM cDNA transferred by an adenovirus vector was sufficiently expressed, leading to a marked reduction of the glycogen accumulation in the skeletal muscle of AMD quail.

Topics: Adenoviridae; Animals; Blotting, Western; Cells, Cultured; Coturnix; Disease Models, Animal; Fibroblasts; Gene Transfer Techniques; Genetic Therapy; Genetic Vectors; Glucan 1,4-alpha-Glucosidase; Glycogen; Humans; Muscle, Skeletal; Promoter Regions, Genetic

Both hypothermia and ischemic preconditioning are known to provide tolerance to myocardial ischemia and reperfusion. The aim of this study was to determine whether hypothermia during the ischemic preconditioning period attenuates the protective effect of ischemic preconditioning.. Experiments were performed in buffer-perfused isolated rabbit hearts. All hearts underwent 45 minutes of regional ischemia, followed by 2 hours of reperfusion. Ischemic preconditioning was elicited by either one or four periods of 5 minutes of regional ischemia. Hypothermia (25 degrees C) was induced beginning either 20 or 50 minutes before the 45-minute period of regional ischemia; normothermia (38 degrees C) was restored 10 minutes before the 45-minute period of regional ischemia. Except for the hypothermic periods noted, hearts were maintained at 38 degrees C.. Normothermic ischemic preconditioning with either one or four cycles of 5 minutes of coronary occlusion resulted in a profound reduction of infarct size (58% reduction with one cycle, p < 0.05; 95% reduction with four cycles, p < 0.01). Hypothermic ischemic preconditioning with one cycle of 5-minute coronary occlusion resulted in no reduction of infarct size but hypothermic ischemic preconditioning with four cycles of 5-minute coronary occlusions resulted in a 94% reduction of infarct size (p < 0.01). Myocardial glycogen and lactate levels were maintained near control levels during hypothermic ischemia.. From these data we conclude that hypothermia during the preconditioning period increases the threshold for eliciting the infarct limitation of ischemic preconditioning.

Topics: Animals; Body Temperature; Coronary Circulation; Disease Models, Animal; Glycogen; Hypothermia, Induced; Ischemic Preconditioning, Myocardial; Lactic Acid; Male; Myocardial Ischemia; Myocardial Reperfusion Injury; Myocardium; Rabbits; Ventricular Function, Left

A new noninvasive therapeutic strategy, which consisted of prenatal intraamniotic administration of porcine surfactant or dexamethasone, was previously used to prevent the functional and structural immaturity of lungs associated with congenital diaphragmatic hernia (CDH), and its effects on lung development were comparable with the changes induced by tracheal ligation (TL). The purpose of this study is to verify if this novel therapeutic modality has any effect in the elevated concentration of lung glycogen and altered contents of lung elastic fiber and collagen promoted by CDH.. A pilot study was performed to investigate in the rabbit model if the infused drugs in the amniotic cavity were aspirated by the CDH and non-CDH fetuses, and if there was correspondence between lung immaturity and high glycogen concentration in lung tissue. Experimental groups consisted of 50 pregnant rabbits that underwent surgery on gestational day 24 or 25 to create left-sided diaphragmatic hernias in 56 fetuses, which were divided in groups according to the procedures: CDH (n = 12), CDH plus TL (n = 16), CDH plus intraamniotic administration of Curosurf (40 mg, n = 12), and CDH plus intraamniotic administration of dexamethasone (n = 16). On gestational day 30, the fetuses were delivered by cesarean section, and 28 normal unoperated fetuses served as controls. The lungs were weighed and submitted to biochemical determination of glycogen, morphometric evaluation of elastic fibers, and colorimetric analysis of collagen.. In all CDH and non-CDH fetuses of the pilot study, the amniotic content was massively aspirated into the lungs and trachea. There was an increase in lung glycogen content of fetuses at 24 days' gestation in comparison with 20-day gestational age fetuses, followed by a decrease in the near full-term fetuses. In the fetuses of the experimental groups, CDH decreased the lung weight to body weight ratios of lungs ipsilateral to the hernia. These changes were reversed by TL but not by intraamniotic administration of surfactant or dexamethasone. Lung glycogen concentrations in the lungs of CDH fetuses were significantly higher than those in the control group. These changes were reversed by intraamniotic administration of surfactant but not by dexamethasone administration or TL. In the lungs ipsilateral to the hernia, surfactant administration promoted a significant decrease in glycogen content to levels lower than control lungs. CDH promoted a decrease in the linear density of elastic fibers in both lungs, ipsilateral and contralateral to the hernia. This alteration was partially corrected by TL and surfactant administration, although dexamethasone administration had no effect. The concentrations of collagen in both lungs were increased significantly by CDH, and these alterations could not be reversed by TL. In the lungs ipsilateral to the hernia, intraamniotic administration of surfactant or dexamethasone promoted a significant decrease in the lung concentration of collagen but not to control levels.. The positive effects of intraamniotic surfactant or dexamethasone administration on lung maturity of fetuses with CDH were observed. This therapy may be a substitute for TL.

Topics: Animals; Collagen; Colorimetry; Dexamethasone; Disease Models, Animal; Elastic Tissue; Female; Fetal Organ Maturity; Glycogen; Hernia, Diaphragmatic; Hernias, Diaphragmatic, Congenital; Ligation; Lung; Pilot Projects; Pregnancy; Pulmonary Surfactants; Rabbits; Trachea

Streptozotocin-induced tumours in the kidneys of experimental animals have been shown to be histologically similar to human renal cell carcinoma. We report the ultrastructural features of renal tumours induced in 15 mice by a single intravenous bolus of 2.5% streptozotocin administered in a dose of 250 mg streptozotocin/kg mouse body weight. Animals were sacrificed 232-361 days after the administration of streptozotocin. On examination both kidneys from each animal contained 1-4 dysplastic tubules and 1-3 discrete tumours per kidney. Twelve dysplastic proximal convoluted tubules showing varying degrees of epithelial atypia and nine tumours exhibiting either a papillary or solid architecture were examined. Dysplastic epithelial cells and tumours of papillary and solid type exhibited complex cell borders with well-developed junctional complexes. The majority of cells contained surface microvilli, and in some cells microvilli-lined intracytoplasmic lumina were observed. Occasional dysplastic epithelial cells and tumour cells contained double-membrane vesicles 120-200 nm in diameter. These were similar to the intracytoplasmic vesicles characteristic of human chromophobe renal cell carcinoma. Intracytoplasmic collections of glycogen granules and flocculant protein were identified in both dysplastic and neoplastic cells, and where prominent they resulted in compression of cytoplasmic organelles. Coated vesicles were commonly observed. These were free within the cytoplasm and were also seen budding from strands of rough endoplasmic reticulum. The distribution of these vesicles suggested a role in protein transport from the rough endoplasmic reticulum. It is concluded that while streptozotocin-induced renal tumours have some ultrastructural features in common with human chromophobe renal cell carcinoma, the overall ultrastructural morphology differs significantly from that described for the various histological types of human renal cell carcinoma.

Topics: Animals; Anti-Bacterial Agents; Carcinoma; Cytoplasm; Disease Models, Animal; Female; Gap Junctions; Glycogen; Humans; Kidney Neoplasms; Mice; Mice, Inbred CBA; Microvilli; Streptozocin

The trace element vanadium was investigated for its anti-neoplastic role in relation to haematological status, hepatic histopathology and histochemical analysis of glycogen in liver. Its impact on the survival of male Sprague-Dawley rats subjected to a two-stage hepatocarcinogenesis regimen was also assessed. Initiation was performed using a single intraperitoneal injection of diethylnitrosamine (DENA) (200 mg/kg) followed by promotion with phenobarbital (0.05%) in a basal diet. Vanadium supplementation as ammonium monovanadate at 0.5 ppm vanadium in drinking water was given ad libitum throughout the experiment (20 weeks), before the initiation (4 weeks), or during the promotional period (14 weeks). At the end of the study, there was a significant decrease in red blood cell count, haemoglobin content, haematocrit value, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration, plasma volume change and total white cell count, with a concurrent alteration in lymphoid:myeloid ratio in DENA control animals compared with their normal counterparts. Vanadium supplementation throughout the study or before the initiation significantly reversed the DENA-induced alterations in most of the haematological indices. A single intraperitoneal injection of DENA also depleted the plasma albumin concentration, raised the plasma globulin content, and decreased the ratio of albumin to globulin. These altered features began to return to normal following vanadium supplementation. Supplementary vanadium also elicited substantial protection against DENA-mediated rat liver carcinogenesis. This was fairly evident from hepatic histology and evaluation of glycogen accumulation by periodic acid-Schiff reaction. The survival of DENA-treated animals was considerably increased in the presence of vanadium. The critical involvement of vanadium in modulating several factors associated with erythropoiesis under carcinogenic challenge may thus have a possible impact on the eventual increased survival of the host.

Topics: Administration, Oral; Animals; Blood Cell Count; Blood Proteins; Carcinoma, Hepatocellular; Cell Nucleus; Cytoplasm; Diet; Disease Models, Animal; Dose-Response Relationship, Drug; Food, Fortified; Glycogen; Liver; Liver Neoplasms, Experimental; Male; Random Allocation; Rats; Rats, Sprague-Dawley; Serum Albumin; Serum Globulins; Survival Rate; Vanadium

The effects of iloprost infusion (100 ng/kg/min for 75 min) alone and in combination with aspirin (3 mg/kg IV bolus) were compared in a canine model of myocardial reperfusion injury. Regional ischemia of 40 min was produced by temporary occlusion of the left anterior descending coronary artery, after which the myocardium was reperfused for a period of 3 hours. Mean arterial pressure (MAP), heart rate (HR), left ventricular end diastolic pressure (LVEDP), positive (+) LVdP/dtmax and negative (-) LVdP/dtmax were monitored. Rate pressure product and (-) dP/dt/Pmax were also derived from the above. Myocardial tissue levels of adenosine triphosphate (ATP), creatine phosphate (CP), glycogen and lactate were estimated. Following reperfusion in the saline treated group, there was a significant fall in (i) MAP, (ii) (+) LVdP/dtmax and (iii) (-) LVdP/dtmax. LVEDP was corrected about 2 hours after reperfusion. Despite correction of lactate accumulation, ATP and glycogen were not restored although the CP store was replenished. The hemodynamic profiles in both iloprost and in combination treated groups were similar; (i) depressed MAP (particularly during iloprost infusion) without any significant change in HR (ii) no significant depression in (+) LVdP/dtmax (iii) depression in (-) LVdP/dtmax but not when corrected for lower Pmax and (iv) a significant reduction in the incidence of reperfusion arrhythmias. Similarly, in both the drug/s treated groups, ATP, CP and lactate were normalised although glycogen store was not restored. The results of this study indicate (i) cardioprotective effect of iloprost even when administered prior to reperfusion and (ii) no additional protective effect of combining iloprost and aspirin.

Topics: Adenosine Triphosphate; Animals; Arrhythmias, Cardiac; Aspirin; Blood Pressure; Cyclooxygenase Inhibitors; Disease Models, Animal; Dogs; Drug Synergism; Drug Therapy, Combination; Glycogen; Heart Rate; Iloprost; Lactic Acid; Myocardial Reperfusion Injury; Myocardium; Phosphocreatine; Ventricular Pressure

Glucocorticoids are potent anti-inflammatory and immunosuppressive therapeutic agents. The protective effect of dexamethasone (DEX) on hepatic phosphoenolpyruvate carboxykinase (PEPCK) transcript level, hepatic NF-kB (nuclear factor-kB) activation, and serum tumor necrosis factor alpha (TNF) formation was investigated in peritoneal sepsis induced by cecal incision in rats. For the control the rats were sham-operated with laparotomies only. Each group (N = 6) was pretreated with either normal saline (NS) or DEX before surgery (NS/Sham, NS/Sepsis, DEX/Sham, and DEX/Sepsis). At 3 hr post cecal incision, DEX treatment inhibited sepsis-induced hepatic NF-kB activation by 23%, suppressed circulating TNF by 50%, reduced serum glucose by 36%, reduced hepatic glycogen depletion by 76%, and attenuated PEPCK mRNA level. These findings suggested that DEX treatment was beneficial in attenuating glucose dyshomeostasis and significantly inhibited two sepsis-induced inflammatory mediators, NF-kB and TNF, in the early phase of peritoneal sepsis. However, in the late (6 hr) septic phase, DEX treatment inhibited serum TNF by 69%, but had no effect on NF-kB activation, glycogen depletion, and PEPCK mRNA level suggesting liver function failure injury.

Topics: Animals; Base Sequence; Blood Glucose; Blotting, Northern; Dexamethasone; Disease Models, Animal; Gene Expression Regulation; Glucocorticoids; Glucose; Glycogen; Homeostasis; Liver; Male; NF-kappa B; Nuclear Proteins; Oligonucleotide Probes; Peritonitis; Phosphoenolpyruvate Carboxykinase (ATP); Rats; Rats, Sprague-Dawley; RNA, Messenger; Time Factors; Tumor Necrosis Factor-alpha

The statement that blood in the articular cavity is cause of cartilage degradation is widely accepted as an axiom. Although the causes of the different articular diseases were explained in numerous studies, none of them has clarified the pathomechanism of haemarthrosis. Our aims were: 1/ to give a morphological description of the blood induced changes in the cartilage, 2/ to verify that the haemarthros is the cause of the cartilage degradation. 10 white rabbits were used in our experimental model. Artificial haemarthros was produced in their left hind knees by intraarticular injection of their own blood. The right hind served as control. The rabbits were divided into to five groups based on the time of the haemarthros (22-50 days). Samples of the condylar cartilage were taken for light, polarization, transmission and scanning electron microscopy examinations. Signs of the disorganization of the matrix structure were showed by polarisation microscope and serious lesions were detected in the perichondrium by scanning electron microscope. Similarity have been suggested amongst the pathomechanism of haemarthrosis and other degenerative cartilage diseases (e. g.: osteoarthrosis, rheumatoid arthritis), so we made the same comparison. In many cases similar morphological changes were observed, as described by other authors in case of degenerative diseases.

Topics: Animals; Arthritis, Rheumatoid; Cartilage Diseases; Cartilage, Articular; Cytoplasm; Disease Models, Animal; Extracellular Matrix; Glycogen; Glycosaminoglycans; Hemarthrosis; Hindlimb; Menisci, Tibial; Microscopy, Electron; Microscopy, Electron, Scanning; Microscopy, Polarization; Osteoarthritis; Porosity; Proteoglycans; Rabbits

Myocardial regions perfused through a coronary stenosis may cease contracting, but remain viable. Clinical observations suggest that increased glucose utilization may be an adaptive mechanism in such "hibernating" regions. In this study, we used a combination of 13C-NMR spectroscopy, GC-MS analysis, and tissue biochemical measurements to track glucose through intracellular metabolism in intact dogs infused with [1-13C]glucose during a 3-4-h period of acute ischemic hibernation. During low-flow ischemia [3-13C]alanine enrichment was higher, relative to plasma [1-13C]glucose enrichment, in ischemic than in nonischemic regions of the heart, suggesting a greater contribution of exogenous glucose to glycolytic flux in the ischemic region (approximately 72 vs. approximately 28%, P < 0.01). Both the fraction of glycogen synthase present in the physiologically active glucose-6-phosphate-independent form (46 +/- 10 vs. 9 +/- 6%, P < 0.01) and the rate of incorporation of circulating glucose into glycogen (94 +/- 25 vs. 20 +/- 15 nmol/gram/min, P < 0.01) were also greater in ischemic regions. Measurement of steady state [4-13C)glutamate/[3-13C]alanine enrichment ratios demonstrated that glucose-derived pyruvate supported 26-36% of total tricarboxylic acid cycle flux in all regions, however, indicating no preference for glucose over fat as an oxidative substrate in the ischemic myocardium. Thus during sustained regional low-flow ischemia in vivo, the ischemic myocardium increases its utilization of exogenous glucose as a substrate. Upregulation is restricted to cytosolic utilization pathways, however (glycolysis and glycogen synthesis), and fat continues to be the major source of mitochondrial oxidative substrate.

Topics: Alanine; Animals; Coronary Disease; Coronary Vessels; Disease Models, Animal; Dogs; Endocardium; Fatty Acids, Nonesterified; Female; Glucose; Glutamic Acid; Glycogen; Glycolysis; Magnetic Resonance Spectroscopy; Male; Oxidation-Reduction; Pericardium; Regional Blood Flow

The effect of chronic hypoxia on neonatal myocardial metabolism remains undefined. With a new neonatal piglet model, we determined changes in myocardial metabolism during global ischemia after chronic hypoxia. Five-day-old piglets (N = 30) were randomly assigned to two groups and exposed to an atmosphere of 8% oxygen or to room air for 28 days before they were killed. Left ventricular myocardium was then analyzed at control and at 15-minute intervals during 60 minutes of global normothermic ischemia to determine high-energy phosphate levels, glycogen stores, and lactate accumulation. Time to peak ischemic myocardial contracture was measured with intramyocardial needle-tipped Millar catheters as a marker of the onset of irreversible ischemic injury. Results showed an initially greater level of myocardial adenosine triphosphate in the hypoxic group (27 +/- 1.2 vs 19 +/- 1.8 micromol/gm dry wt, p = 0.001) and a delay in adenosine triphosphate depletion during 60 minutes of global ischemia compared with the control group. Initial energy charge ratios (1/2 adenosine diphosphate + adenosine triphosphate/adenosine monophosphate + adenosine diphosphate + adenosine triphosphate) were also greater in the hypoxic group (0.96 +/- 0.01 vs 0.81 +/- 0.04, p = 0.01) and remained so throughout global ischemia. Initial glycogen stores were greater in the hypoxic group (273 +/- 13.3 vs 215 +/- 14.7 micromol/gm dry weight, p = 0.02) when compared with the control group. Lactate levels in the hypoxic group were initially higher (19.1 +/- 6.4 vs 8.9 +/- 3.1 micromol/gm dry weight, p = 0.001) compared with control levels and remained elevated throughout 60 minutes of ischemia. Time to peak ischemic contracture was prolonged in the hypoxic group (69.5 +/- 1.8 vs 48.9 +/- 1.4 minutes, p = 0.001) compared with the controls group. These data show that chronic hypoxia results in significant myocardial metabolic adaptive changes, which in turn result in an improved tolerance to severe normothermic ischemia. These beneficial effects are associated with elevated baseline glycogen storage levels and an accelerated rate of anaerobic glycolysis during ischemia.

Topics: Animals; Animals, Newborn; Chronic Disease; Disease Models, Animal; Glycogen; Hypoxia; Myocardial Contraction; Myocardium; Swine; Ventricular Function, Left

Liver and skeletal muscle glycogen metabolism were investigated in rats 1 and 4 weeks after bile duct ligation (BDL) and in pair-fed, sham-operated control rats. Livers were subjected to morphometric analysis to express glycogen content and enzyme activities per mL hepatocytes. One week after BDL, the hepatic glycogen content was 28.8 +/- 13.8 versus 38.6 +/- 16.4 mg/mL hepatocyte in BDL and control rats, respectively. Total activity of glycogen synthase (50.2 +/- 7.0 vs. 63.5 +/- 9.4 mU/mL hepatocytes) and glycogen phosphorylase (59.4 +/- 12.9 vs. 90.8 +/- 18.9 U/mL) were significantly reduced in BDL whereas the active fraction of glycogen synthase (27 +/- 6 vs. 38 +/- 5%) but not of glycogen phosphorylase was reduced. The skeletal muscle glycogen content was not different between BDL and control rats. Four weeks after BDL, hepatic glycogen content was further reduced (20.5 +/- 14.2 vs. 52.9 +/- 6.4 mg/mL). Total activity of glycogen synthase (38.8 +/- 12.1 vs. 60.1 +/- 4.6 mU/mL hepatocytes) and glycogen phosphorylase (127 +/- 19 vs. 178 +/- 33 U/mL hepatocytes) were both reduced in BDL rats as were their corresponding active fractions (30 +/- 18 vs. 66 +/- 8% and 58 +/- 10 vs. 76 +/- 10). At this time point, the glycogen content in soleus muscle was decreased by 64% in BDL. The glucagon plasma concentration was increased in BDL rats at both time points. There were positive correlations between the volume fraction and both hepatic glycogen content and total activity of hepatic glycogen synthase. Plasma glucagon and the active fraction of hepatic glycogen synthase were negatively correlated. The current studies show a progressive decrease in the hepatic and skeletal muscle glycogen content in BDL rats. The observed decrease in the activities of glycogen synthase and phosphorylase suggest that reduced glycogen synthesis is the major mechanism leading to the reduction in the hepatic glycogen content in BDL rats.

Topics: Animals; Cholestasis, Extrahepatic; Disease Models, Animal; Glycogen; Glycogen Synthase; Ligation; Liver; Liver Glycogen; Male; Muscle, Skeletal; Phosphorylases; Rats; Rats, Sprague-Dawley

Structural changes of renal arteries and glomeruli were studied in 25 dogs with hemodynamic model of coarctation of the aorta in different terms of experiment by of histochemical, histoenzymological and morphometric methods also using 10 control animals. Dystrophic processes were established to develop in media of renal arteries and myocytes within the first week of the disease induction. In later stages of the experiment a number of adaptive, compensatory and pathobiological changes associated with the decrease of renal basin blood supply appear in renal vessels. First lie in atrophia of the muscular coat circular layer in renal arteries and arterioles, second--in reorganization of part of them and third--in sclerosis and hyalinosis of arteriolar branches and glomeruli.

Topics: Animals; Aortic Coarctation; Arteries; Arterioles; Disease Models, Animal; Dogs; Glycogen; Histological Techniques; Kidney; Muscle, Smooth, Vascular; Periodic Acid-Schiff Reaction; Time Factors

Impaired glycogen synthesis is present in subjects at risk for developing non-insulin-dependent diabetes mellitus (NIDDM), suggesting that it is a primary defect in NIDDM. To examine whether defects in glycogen metabolism are present at birth in an animal model of NIDDM, glycogen synthase (GS), glycogen phosphorylase (GP), and total glycogen content were measured in liver and quadriceps muscle of 1-day- and 20-week-old insulin-resistant New Zealand Obese (NZO) mice and control (NZC) mice. In livers of both neonatal and adult NZO mice, active GS was reduced by 54% and 36%, respectively, as compared with that in NZC mice (P < .03). Total liver GS activity was the same in neonates, but was 65% higher in adult NZO as compared with NZC mice (P < .02). Liver glycogen was 28% lower at birth in NZO mice (P < .03), but was 49% higher at 20 weeks of age. Active and total GP were the same in NZO and NZC animals, despite hyperinsulinemia in 20-week-old NZO mice. In muscle, active GS was reduced by 41% in both 1-day- and 20-week-old NZO mice (P < .02). Total GS was also lower in NZC mice at 1 day of age (P < .01), but not at 20 weeks. No differences were detected in GP activity or in total glycogen content in muscle. Therefore, reduced GS activity is an early defect present at birth in the insulin-resistant NZO mouse in both liver and muscle. However, it is not the sole determinant of the amount of glycogen deposited in tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Aging; Animals; Animals, Newborn; Blood Glucose; Diabetes Mellitus, Experimental; Disease Models, Animal; Female; Glycogen; Glycogen Synthase; Liver; Liver Glycogen; Male; Mice; Mice, Obese; Muscle, Skeletal; Phosphorylases

Acetylshikonin, a naphthoquinone isolated from the Chinese herb medicine, tzu ts'ao, was demonstrated to inhibit the polymyxin B-induced hind-paw edema in normal as well as in adrenalectomized mice. Liver glycogen content was increased in adrenalectomized mice pretreated with dexamethasone, but not with acetylshikonin. Like diphenhydramine, methysergide and isoproterenol, acetylshikonin reduced the plasma exudation evoked in dorsal hind-paw skin by antidromic stimulation of the saphenous nerve, and in passive cutaneous anaphylactic reaction, bradykinin-, substance P-, compound 48/80-, histamine- and serotonin-induced ear edema. Indomethacin was ineffective in these respects. Bradykinin- and substance P-induced plasma exudation were also significantly reduced when [Thi5,8,D-Phe7]bradykinin and [D-Pro2,D-Trp7,9]substance P were coinjected with bradykinin and substance P, respectively. In isolated rat peritoneal mast cell preparation, acetylshikonin produced a concentration-dependent inhibition of histamine and beta-glucuronidase release from mast cells challenged by compound 48/80. In compound 48/80-pretreated mice, acetylshikonin and isoproterenol produced significantly more inhibitory effect on bradykinin- and substance P-induced plasma exudation than did diphenhydramine in combination with methysergide. Pretreatment with diphenhydramine/methysergide in compound 48/80-pretreated mice significantly further reduced the bradykinin- and substance P-induced plasma exudation if [Thi5,8,D-Phe7]bradykinin and [D-Pro2,D-Trp7,9]substance P were coinjected with bradykinin or substance P, respectively. The results suggest that the inhibitory effect of acetylshikonin on the edematous response is due neither to the release of steroid hormones from the adrenal gland nor to the glucocorticoid activity, but probably partly to the suppression of mast cell degranulation and partly to protection of the vasculature from mediator challenge.

Topics: Adrenalectomy; Animals; Anthraquinones; Bradykinin; Capillary Permeability; Cell Degranulation; Dexamethasone; Diphenhydramine; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Interactions; Drugs, Chinese Herbal; Edema; Glucuronidase; Glycogen; Hindlimb; Histamine; Indomethacin; Liver; Mast Cells; Methysergide; Mice; p-Methoxy-N-methylphenethylamine; Polymyxin B; Substance P

CI-959 is an antiallergic/antiinflammatory agent currently in development. In rats, daily bolus intravenous administration of CI-959 at doses > or = 10 mg/kg was associated with development of cardiac hypertrophy. There was no morphologic or biochemical evidence of myocyte injury, and cardiac hypertrophy rapidly reversed after treatment was discontinued. Cardiac hypertrophy was not evident when CI-959 was given orally or by continuous intravenous infusion with ALZA osmotic pumps. Maximum plasma drug concentrations (Cmax) were significantly higher when CI-959 was given by bolus intravenous injection, suggesting that cardiac effects were dependent on high Cmax concentrations. When neonatal rat cardiomyocytes were exposed to CI-959 in vitro, there was no evidence of myocyte enlargement or increased protein content. Cardiac hypertrophy was prevented by pretreatment with nonselective beta- and beta 1-selective adrenoceptor blockers as well as with central sympatholytics. beta 2- and alpha-adrenoceptor blockers were ineffective in preventing cardiac hypertrophy. Bolus intravenous CI-959 administration resulted in prolonged hypotension and associated increase in plasma catecholamine levels, with apparent inhibition of reflex tachycardia. We conclude that CI-959-associated cardiac hypertrophy in rats was not a direct drug effect but instead was probably mediated by endogenous catecholaminergic stimulation of cardiac beta 1-adrenoceptors.

Topics: Administration, Oral; Adrenergic alpha-Antagonists; Adrenergic beta-Antagonists; Animals; Anti-Inflammatory Agents, Non-Steroidal; Blood Pressure; Cardiomegaly; Catecholamines; Cells, Cultured; Creatine Kinase; Disease Models, Animal; Glycogen; Heart; Heart Rate; Infusion Pumps, Implantable; Infusions, Intravenous; L-Lactate Dehydrogenase; Microscopy, Electron; Myocardium; Rats; Rats, Sprague-Dawley; Rats, Wistar; Tetrazoles; Thiophenes

The biochemical effect of S-1,3-butanediol on streptozotocin induced diabetic rats was studied. Rats were made diabetic by the intraperitoneal injection of 40 mg/kg body weight streptozotocin in sodium citrate buffer. A dosage of 25 mmol/kg body weight of S-1,3-butanediol was injected intraperitoneally for treatment. The streptozotocin induced diabetic rats showed a marked increase in blood glucose level, and significant increase in the level of cholesterol, triglycerides and free fatty acids. The glycogen levels in liver and kidney were greatly decreased in diabetic rats. Treatment with butanediol normalised the glucose and glycogen level but had no significant effect on protein and lipid levels.

Topics: Animals; Blood Glucose; Blood Proteins; Butylene Glycols; Cholesterol; Diabetes Mellitus, Experimental; Disease Models, Animal; Fatty Acids, Nonesterified; Glycogen; Injections, Intraperitoneal; Kidney; Liver; Male; Rats; Stereoisomerism; Streptozocin; Triglycerides

Severe lactic acidosis usually accompanies intense endurance exercise. It has been postulated that glycogen depletion working in concert with elevated muscle and plasma lactate levels lead to a concomitant reduction in pH. Their cumulative effect during prolonged physical exertion now leads to muscular fatigue and eventually limit endurance capacity. Therefore in the present study, dichloroacetate (DCA), a compound which enhances the rate of pyruvate oxidation thus reducing lactate formation, has been evaluated in a validated rat model of sub-maximal exercise performance. Male rats (350 g) were divided into two groups (control-saline, i.v. and DCA 5 mg/kg, i.v.) and were exercised to exhaustion in a chamber (26 degrees C) on a treadmill (11 m/min, 6 degrees incline). When compared to controls, the DCA-treated rats had longer run times (169 vs 101 min) and a decreased heating rate (0.020 vs 0.029 degrees C/min). In addition, DCA attenuated the increase in plasma lactate (28 vs 40 mg/dl) and significantly reduced both the rate and absolute amount of depletion of muscle glycogen stores. These results suggest that the activation of pyruvate dehydrogenase activity by DCA resulted in a reduction in the rate of glycogenolysis in addition to decreasing lactate accumulation by presumably limiting the availability of pyruvate for conversion to lactate, therefore increasing muscle carbohydrate oxidation via the TCA cycle. Thus DCA effected a significant delay in muscle fatigue.

Topics: Acidosis, Lactic; Animals; Body Temperature Regulation; Dichloroacetic Acid; Disease Models, Animal; Enzyme Activation; Glycogen; Lactates; Liver; Male; Muscle Fatigue; Muscle, Skeletal; Oxidation-Reduction; Physical Endurance; Physical Exertion; Pyruvate Dehydrogenase Complex; Pyruvates; Rats; Rats, Sprague-Dawley; Running; Time Factors

We used the intragastric feeding rat model for alcoholic liver disease to investigate alterations in glucose transporter isoforms GLUT 1 and GLUT 2 in response to different dietary fats and ethanol. Six groups of rats (three rats/group) were fed ethanol or dextrose with either saturated fat, corn oil, or fish (menhaden) oil. All control animals were pair fed the same diets as ethanol-fed rats except that ethanol was isocalorically replaced by dextrose. In all animals, the following were assessed: pathological changes in the liver, immunohistochemical and Western blot analysis of GLUT 1 and GLUT 2 isoforms, and glycogen distribution. The most severe pathological changes were seen in fish oil/ethanol fed rats, moderate changes were seen in the corn oil/ethanol group and no changes were observed in the dextrose-fed or saturated fat/ethanol groups. In the groups of rats showing pathological liver injury (corn oil/ethanol and fish oil/ethanol), the depletion in liver glycogen was accompanied by decreased GLUT 2 expression and increased GLUT 1 expression. A decrease in glycogen and GLUT 2 expression was also seen in the fish oil/dextrose-fed rats. We hypothesize that the shift in glucose transporters from GLUT 2 to GLUT 1 probably reflects a compensatory response to attenuated gluconeogenic activity and to meet the increased intracellular demand for glucose. This demand for glucose in the presence of depleted glycogen may serve to provide a source for ATP synthesis in the centrilobular zone where hypoxia occurs secondary to ethanol metabolism.

Topics: Animals; Corn Oil; Dietary Fats; Disease Models, Animal; Ethanol; Fish Oils; Glycogen; Liver; Liver Diseases, Alcoholic; Male; Monosaccharide Transport Proteins; Rats; Rats, Wistar

Limitation of myocardial injury and infarction has been demonstrated by interventions such as ischemic preconditioning or the use of pyruvate as a substrate, which reduces glycogen content before, and acidosis during, ischemia. An isolated perfused rat heart model of global ischemia was employed to test the hypothesis that glycogen depletion reduces ischemic injury as measured by creatine kinase release. 31P-nuclear magnetic resonance spectroscopy was used to measure high-energy phosphates (ATP and phosphocreatine), phosphomonoesters (PME), and intracellular pH. Compared with control glucose-perfused hearts with normal glycogen content (1.49 +/- 0.13 mg Glc/g wet wt), glycogen-depleted pyruvate, ischemic preconditioned, and glycogen-depleted glucose hearts all had reduced glycogen content before ischemia (0.62 +/- 0.16, 0.81 +/- 0.10, and 0.67 +/- 0.12 mg Glc/g wet wt, respectively; P = 0.003) and significantly higher pH at the end of ischemia (5.85 +/- 0.02, 6.33 +/- 0.06, 6.24 +/- 0.04, and 6.12 +/- 0.02 in control, glycogen-depleted pyruvate, preconditioned, and glycogen-depleted glucose-perfused hearts, respectively; P < 0.01), although acidification during the initial phase of ischemia was differentially affected by the three interventions. Glycogen-depleted pyruvate and preconditioned hearts had reduced PME accumulation, greater recovery of function and phosphocreatine, and lower creatine kinase release on reperfusion, whereas glycogen-depleted glucose-perfused hearts were similar to control hearts. In summary, glycogen depletion by these three methods limits the fall in pH during global ischemia, although glycogen depletion in the absence of preconditioning does not limit ischemic injury.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adenosine Triphosphate; Animals; Creatine Kinase; Disease Models, Animal; Glucose; Glycogen; Glycolysis; Hydrogen-Ion Concentration; In Vitro Techniques; Intracellular Fluid; Magnetic Resonance Spectroscopy; Male; Myocardial Ischemia; Perfusion; Phosphates; Phosphocreatine; Rats; Rats, Sprague-Dawley; Ventricular Function, Left

Several studies on both humans and animal models have reported a pathogenetic relationship among hyperinsulinism, insulin resistance, and hypertension. We have previously evaluated whole body glucose disposal and insulin sensitivity in different models of hypertensive rats, showing an increase rather than an impairment of glucose metabolism, which in turn was due to an improved ability of insulin to channel the absorbed glucose towards the nonoxidative disposal. Aiming to confirm our previous findings we performed the direct assay of skeletal muscle glycogen synthase on tissue samples from the previous clamp studies, as a rate limiting step enzyme of glycogen synthesis, under conditions of physiologic hyperinsulinemia and euglycemia. Glycogen synthase was assayed on samples from rectus muscle tissues of spontaneously hypertensive rats and high sodium, one kidney, one figure-8 hypertensive rats. Compared to controls, our data show an increased activity of glycogen synthase in the hypertensive animals, which is consistent with the increased glycogen synthesis previously reported. In conclusion, under our experimental conditions, hypertension and chronic hyperadrenergism are associated with an increased ability of insulin to stimulate glucose uptake and disposal. These latter effects are mainly due to an increase in nonoxidative disposal and glycogen synthase activity.

Topics: Animals; Disease Models, Animal; Glucose; Glycogen; Glycogen Synthase; Hypertension; Muscle, Skeletal; Rats; Rats, Inbred SHR; Rats, Inbred WKY

Several investigators have reported that feeding a semi-synthetic diet of casein and dextrose to New Zealand White (NZW) rabbits will increase total serum cholesterol concentration, principally through an increase in the beta-lipoprotein fractions, thereby creating a useful model for atherosclerosis research. Although there is evidence to suggest that the dextrose/casein diet alters low-density lipoprotein receptor and bile acid clearance of cholesterol, the underlying mechanism is not completely understood. The effects of the diet on the overall physiology of the rabbit have received little attention. In this study feeding a diet of casein and dextrose of male NZW rabbits for 4 weeks resulted in changes in the serum lipid concentrations. During that time the rabbits fed the dextrose/casein diet gained less weight than did control rabbits. In the test diet rabbits, liver aspartate and alanine transaminase activities were increased from baseline values of 27 +/- 2 U/L and 89 +/- 9 U/L respectively to 112 +/- 21 U/L and 281 +/- 34 U/L respectively, then returned to the high end of the reference range. Necropsy findings included hepatomegaly caused by vacuolar hepatopathy in 19 or 20 experimental rabbits; rabbits fed the control diet had no hepatic lesions. Ultrastructural analysis revealed that enlargement of the liver cells was due to glycogen deposition. Adrenal glands from animals fed the experimental diet had a minimal change in the size of the adrenocortical cells consisting of slight ballooning and rarefaction of the cytoplasm. In a second study the level of dietary fiber was doubled. This resulted in a three-fold increase in lipid concentrations, compared with the fivefold increase in the first study. The liver enzyme activities were increased to the same extent as in the first study. Histologic changes were comparable to those in the first study. The activity of hepatic cholesterol 7alpha-hydroxylase was 3.7 +/- 0.4 pmol/min/mg of protein, compared with the control value of 7.7 +/- 1.1 pmol/min/mg of protein (P < 0.05) in the second study. The improved rate of weight gain and the lesser increase in total serum cholesterol concentration in the second study with increased dietary fiber suggest that two separate activities may be involved. Although the level of dietary fiber may be related to weight gain and total serum cholesterol values, the relation to the decrease in liver transaminase activities in study 1 was probably coincidental. It appears tha

Topics: Adrenal Glands; Animals; Brain; Caseins; Cholesterol; Cholesterol 7-alpha-Hydroxylase; Diet; Disease Models, Animal; Food, Formulated; Glucose; Glycogen; Hydroxymethylglutaryl CoA Reductases; Hyperlipidemias; Lipoproteins; Liver; Male; Microscopy, Electron; Organ Size; Rabbits

Angiotensin-converting enzyme (ACE) inhibitors can improve cardiac function independent of their blood pressure (BP)-lowering actions. We investigated the effect of chronic subantihypertensive ACE inhibitor treatment on functional and biochemical cardiac parameters in stroke-prone spontaneously hypertensive rats (SHRSP). Animals were treated in utero and subsequently to age 20 weeks with the ACE inhibitor perindopril (0.01 mg/kg/day). The contribution of endogenous bradykinin (BK) potentiation to the actions of the ACE inhibitor was assessed by cotreatment with the BK beta 2-receptor antagonist Hoe 140 (500 micrograms/kg/day subcutaneously, s.c.) from age 6 to 20 weeks and by measurement of myocardial prostacyclin and cyclic GMP concentrations. Chronic low-dose perindopril treatment had no effect on development of hypertension and left ventricular hypertrophy (LVH), but perindopril improved cardiac function, as demonstrated by increased LV pressure (LVP) (19.4%) and LVdp/dtmax (27.8%) but no change in heart rate (HR). The activities of lactate dehydrogenase (LDH) and creatine kinase (CK) as well as lactate concentrations in the coronary venous effluent were reduced by 39.3, 50, and 60.6%, respectively. Myocardial tissue concentrations of glycogen and the energy-rich phosphates ATP and CK were increased by 16.3, 33.1, and 28.2%, respectively. All ACE inhibitor-induced effects on cardiac function and metabolism were abolished by concomitant chronic BK receptor blockade. Cardiac prostacyclin concentrations were threefold elevated in perindopril-treated animals whereas cardiac cyclic GMP concentration remained unchanged as compared with that of controls. Our data demonstrate that chronic low-dose ACE inhibitor treatment can improve cardiac function and metabolism by potentiating endogenous BK.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: 6-Ketoprostaglandin F1 alpha; Angiotensin-Converting Enzyme Inhibitors; Animals; Blood Pressure; Bradykinin; Cerebrovascular Disorders; Coronary Circulation; Creatine Kinase; Cyclic GMP; Disease Models, Animal; Glycogen; Heart; Heart Rate; Hypertension; Hypertrophy, Left Ventricular; Indoles; L-Lactate Dehydrogenase; Myocardium; Perindopril; Rats; Rats, Inbred SHR

The role of low-dose aspirin (3 mg/kg, i.v.) in attenuating ischemic reperfusion injury was studied in a canine model. Regional ischemia for 40 min was produced by temporary occlusion of the left anterior descending coronary artery and thereafter reperfusion instituted for 3 h. Mean arterial pressure (MAP), heart rate (HR), left ventricular end diastolic pressure (LVEDP), positive (+) LV dP/dtmax and negative (-) LV dP/dtmax were monitored along with myocardial adenosine triphosphate (ATP), creatine phosphate (CP), glycogen and lactate. Following reperfusion, there was a significant fall in (i) MAP, (ii) (+) LV dP/dtmax and (iii) (-) LV dP/dtmax. LVEDP was corrected after about 2 h of reperfusion. Replenishment of only myocardial CP occurred, without any change in ATP and glycogen, although lactate accumulation was corrected. Aspirin administered 15 min before reperfusion (post-treatment) caused normalisation of LVEDP within 15 min and prevented any deterioration in (-) LV dP/dtmax, although it had no effect on MAP and (+) LV dP/dtmax. After 3 h of reperfusion (post-treatment), myocardial ATP, CP, glycogen and lactate contents became normal. The number of premature ventricular complexes was significantly reduced after aspirin treatment. The present study indicates that low-dose aspirin post-treatment can ameliorate at least some of the deleterious consequences of reperfusion injury of the myocardium.

Topics: Adenosine Triphosphate; Analysis of Variance; Animals; Aspirin; Blood Pressure; Creatinine; Disease Models, Animal; Dogs; Glycogen; Heart Rate; Injections, Intravenous; Lactates; Lactic Acid; Myocardial Ischemia; Myocardial Reperfusion Injury

Skeletal muscle is insulin resistant in the obese Zucker rat. Endurance training reduces muscle insulin resistance, but the effects of a single acute exercise session on muscle insulin resistance in the obese Zucker rat are unknown. Therefore, insulin responsiveness of muscle glucose uptake was measured in 15-week-old obese rats either 1, 48, or 72 hours after two hours of intermittent exercise (30:30 min; work:rest). Hindlimbs of sedentary lean (LS) and obese (OS) rats and exercised obese (OE) rats were perfused after a 10-hour fast under both basal (0 mU x ml(-1)) and maximal (20 mU x ml(-1)) insulin concentrations to measure net glucose uptake. Insulin responsiveness of net glucose uptake was significantly reduced in OS compared to LS (8.5 +/- 1.6 vs 15.3 +/- 2.0 micromol x g(-1) x h(-1), respectively). Compared to OS, insulin responsiveness of net glucose uptake was significantly increased by 56% and 80% at 1 hour and 48 hours after acute exercise. However, 72 hours after acute exercise, the increased insulin responsiveness of net glucose uptake was no longer evident. These results indicate that improved responsiveness of muscle glucose uptake persists for at least 48 hours after two hours of acute intermittent exercise in 15-week-old obese Zucker rats.

Topics: Adipose Tissue; Animals; Biological Transport; Blood Glucose; Body Mass Index; Disease Models, Animal; Glucose; Glycogen; Insulin; Insulin Resistance; Male; Muscle, Skeletal; Muscles; Obesity; Oxygen; Perfusion; Physical Conditioning, Animal; Rats; Rats, Zucker; Time Factors

Gram-negative sepsis/septic shock in the newborn continues to be a major medical problem, causing high mortality. Hyperglycemia followed by hypoglycemia is a common symptom in endotoxic shock. However, the mechanism of newborn glucoregulatory response to endotoxin has not been well understood. Paradoxically, monocyte-phagocytes can contribute to shock by overwhelming secretion of cytokines and also host defense by detoxifying endotoxin. Since monocyte-phagocyte function is immature in the newborn, this study was performed to evaluate Kupffer cell's role in liver glycogenolysis during endotoxic shock. Endotoxin (LPS) induced hyperglycemia in 10-day-old rats, and increased net glucose output in the isolated perfused liver. 1) Cytarabine decreased Kupffer cell function (decreased hepatic colloid carbon uptake) and blunted LPS-increased liver net glucose output in the Cytarabine + LPS-treated group (104 +/- 4 vs. 146 +/- 3 micrograms/min/g wet liver in the LPS-treated group: P < .001). 2) Indomethacin (IND) suppressed LPS-induced liver net glucose output in the LPS + IND-treated group (133 +/- 5 vs. 146 +/- 3 micrograms/min/g wet liver, P < .05). Thus, prostaglandins were suggested to contribute to glycogenolysis in the 10-day-old rat liver. 3) Phorbol 12-myristate 13-acetate (PMA) increased liver net glucose output (166 +/- 4 micrograms/min/g wet liver), and H-7, a protein kinase C inhibitor, blunted PMA-induced liver glucose output (140 +/- 2 micrograms/min/g wet liver, P < .05). H-7 enhanced LPS-induced liver net glucose output (196 +/- 9 micrograms/min/g wet liver, P < .01). Therefore, protein kinase C may not be the dominant cell signaling system for LPS stimulation in suckling rat Kupffer cells.

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Animals; Animals, Newborn; Cytarabine; Disease Models, Animal; Glycogen; Indomethacin; Isoquinolines; Kupffer Cells; Lipopolysaccharides; Liver; Piperazines; Rats; Rats, Sprague-Dawley; Shock, Septic; Tetradecanoylphorbol Acetate

To evaluate the long-held concept that acidic guanidines lack glycemic effects, guanidinoalkanoic acids and the biguanide metformin (positive control) were administered to KKAy mice, a model of noninsulin-dependent diabetes. Two acidic guanidines, 3-guanidinopropionic acid (3-GPA) and guanidinoacetic acid, decreased the plasma glucose level; other compounds were ineffective. 3-GPA was more potent than even metformin. Insulin suppression tests in KKAy mice indicated that improved insulin sensitivity was the mode of action for 3-GPA. Glycemic effects in KKAy mice resulted from increased glucose disposal whereas gluconeogenesis, hepatic glycogen content and intestinal glucose absorption were unchanged. 3-GPA's glycemic effect was corroborated in two other models of noninsulin-dependent diabetes. In ob/ob mice, the compound reduced hyperglycemia, polyuria, glycosuria and hyperinsulinemia. In insulin-resistant rhesus monkeys, it increased the disappearance of i.v. glucose. The glycemic action of 3-GPA required the presence of some circulating insulin as well as hyperglycemia because the compound was ineffective in normoglycemic mice, insulinopenic Chinese hamsters and streptozotocin-diabetic rats. These data indicate that acidic guanidine derivatives can ameliorate hyperglycemia in animal models of noninsulin-dependent diabetes. Because acidic derivatives uniquely lack the propensity of guanidine compounds for inducing lactic acidosis, our finding suggests a new approach for developing improved antidiabetes compounds from this chemical class.

Topics: Animals; Blood Glucose; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Gluconeogenesis; Glucose; Glycogen; Guanidines; Hyperglycemia; Insulin; Insulin Resistance; Intestinal Absorption; Liver Glycogen; Macaca mulatta; Male; Metformin; Mice; Mice, Inbred C57BL; Mice, Obese; Muscles; Propionates; Structure-Activity Relationship

1. The relationship between hypertension, obesity, non-insulin-dependent diabetes mellitus and various parameters of glucose metabolism was studied. Lean and obese rats of the SHR/N-cp and LA/N-cp congenic strains were studied at four months of age. 2. Tritium and 14C-labeled glucoses were infused in one set of rats while tritiated water and 14C-labeled alanine were infused in a second group. 3. Glucose oxidation, turnover, conversion to glycogen, fatty acid synthesis, and alanine conversion to glucose were determined, as were blood pressure, pulse pressure and heart rate. 4. The presence of obesity influenced body weight, body fat, de novo fatty acid synthesis, organ weights, glucose mass, glucose oxidation, glucose synthesis, glucose carbon turnover and pulse pressure. 5. It had no effect on glycogen synthesis, tissue glycogen levels, blood glucose, glucose space, or blood pressure. 6. Strain differences were observed in final body weight, organ weights, blood pressure, pulse pressure, hepatic fatty acid synthesis, glucose mass, glucose space, glucose synthesis, liver glycogen levels and glucose conversion to muscle glycogen. 7. Strain-phenotype interaction effects were observed on glucose incorporation into hepatic glycogen, Cori cycle activity, hepatic de novo fatty acid synthesis, final body weight, fat pad weight, heart weight, and mean arterial pressure. 8. These results suggest that although obesity and hypertension are genetic traits in these rats, these traits are independent in their influence on the metabolism of glucose and the development of non-insulin-dependent diabetes mellitus.

Topics: Animals; Blood Glucose; Body Weight; Diabetes Mellitus, Type 2; Disease Models, Animal; Fatty Acids; Glucose; Glycogen; Hemodynamics; Hypertension; Liver; Male; Muscles; Obesity; Organ Size; Rats; Rats, Inbred SHR

The first two mutations causing hereditary glucose-6-phosphate isomerase (GPI) deficiency associated with chronic nonspherocytic hemolytic anemia in nonhuman mammals are described in the mouse. As in humans, the hemolytic syndrome, which is characterized by a diminished erythrocyte number, lower hematocrit, lower hemoglobin, higher number of reticulocytes and plasma bilirubin concentration, as well as increased liver- and spleen-somatic indices, was exclusively manifested in homozygous mutants. In comparison with wild type, heterozygous individuals exhibited neither hematologic differences nor alterations of other physiologic parameters, including plasma concentration of glucose, pyruvate and lactate, body weight, organo-somatic indices of liver, lung, kidney, spleen, and heart, as well as viability. Glycolytic intermediates, adenine nucleotides, and metabolic rate were not significantly altered in erythrocytes from heterozygotes. On the contrary, if allowance is made for the young erythrocyte population, homozygous mutant erythrocytes showed an increased concentration of glucose-6-phosphate and normal or decreased concentrations of glycolytic metabolites following the enzymatic block. The concentration of adenosine triphosphate and the glycolytic rate also appeared to be reduced. Homozygous anemic mice showed hepatosplenomegaly and typical adaptations to hypoxia, such as an elevated heart-somatic index and, for one mutant line, an enhanced lung-somatic index. Further, these animals were characterized by a marked reduction of body weight and an increase of lethality both correlated with the degree of enzyme deficiency in tissues. The latter findings were attributed to a reduced glycolytic capability of the whole organism caused by the enzyme defect in tissues, rather than representing secondary consequences of GPI deficiency in erythrocytes. The similarity in physicochemical and kinetic properties of the mutant murine proteins reported earlier with those of allozymes found in human GPI deficiency, as well as the comparable metabolic and physiologic consequences of this enzyme defect in mice and humans support that these murine mutants are excellent animal models for the human disease.

Topics: Adenine Nucleotides; Anemia, Hemolytic, Congenital Nonspherocytic; Animals; Bilirubin; Disease Models, Animal; Erythrocyte Count; Erythrocytes; Glucose-6-Phosphate Isomerase; Glycogen; Glycolysis; Hematocrit; Heterozygote; Homozygote; Liver; Mice; Mice, Inbred C3H; Mice, Mutant Strains; Mutation; Organ Size; Reticulocytes; Spleen

A study was made of the character of disorders of glycogen metabolism and dynamics of the glycogen synthetic properties of sensorimotor cortical neurons at different stages of dystrophic processes under chronic irritation of the anterior cervical ganglion. The authors demonstrate the local glycogen synthesis in synapse ultrastructures, which is of paramount importance for local homeostasis, ensuring high plasticity and dynamism of cortical synapses in information transmission. Decimetric radiotherapy revealed that the sclerosed sympathetic ganglion exerts a permanent tonic effect on the regulation of intracerebral vessels. It may be assumed that control of sympathetic fibers from the cervical ganglion is aimed to a definite measure at specialized regulation of energy brain supply.

Topics: Animals; Atrophy; Body Temperature; Cats; Cerebrovascular Circulation; Chronic Disease; Disease Models, Animal; Ganglia, Sympathetic; Glycogen; Microscopy, Electron; Sclerosis; Somatosensory Cortex; Time Factors

The effect of a supraphysiological concentration of insulin on gluconeogenesis from L-[U14C] lactate was studied in hepatocytes isolated from control mice and mice made obese by a single injection of gold-thioglucose (GTG). At the time of experimentation (10-12 weeks post GTG injection) the obese mice weighted significantly more than controls (41.7 +/- 0.5 vs. 29.6 +/- 0.8 g respectively; P < 0.001), and exhibited fasting hyperinsulinaemia (35.9 +/- 4.6 vs. 21.3 +/- 4.2 microU/ml; P < 0.05) and hyperglycaemia (16.4 +/- 1.2 vs. 9.2 +/- 1.1 mmol/l; P < 0.001). The amount of lactate converted to glucose by hepatocytes isolated from GTG-obese mice was significantly greater than from lean controls (322 +/- 44 vs. 209 +/- 20 nmol/30 min/10(6) cells; P < 0.05). The addition of 10(-6)M insulin to the incubations significantly reduced lactate conversion to glucose by hepatocytes isolated from control mice (209 +/- 20 vs. 123 +/- 22 nmol/30 min/10(6) cells; P < 0.02), but there was no effect of insulin on glucose production from lactate by hepatocytes isolated from GTG-obese mice (322 +/- 44 vs. 294 +/- 47 nmol/30 min/10(6) cells). Glycogen production and triacylglycerol glycerol production from L-[U14C] lactate were also significantly increased in hepatocytes from GTG-obese mice compared with controls. There was no effect of 10(-6)M insulin on glycogen or triacylglycerol glycerol production from lactate by hepatocytes from GTG-obese mice but the addition of 10(-6)M insulin to the incubations of control hepatocytes significantly reduced the amount of lactate converted to glycogen and triacylglycerol glycerol.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Aurothioglucose; Cells, Cultured; Diabetes Mellitus, Type 2; Disease Models, Animal; Fatty Acids; Gluconeogenesis; Glucose; Glycogen; Insulin; Lactates; Liver; Male; Mice; Mice, Inbred CBA; Obesity; Triglycerides

The high molecular weight glycogen associated with the lysosomal compartment in glycogen storage disease type VIII is more resistant to degradation by proteinase than normal glycogen. The assembly of large glycogen particles on disulphide-linked protein backbones has been confirmed and the disulphide-reducing nature of the lysosome appears to confer an advantage in the amylolytic degradation of glycogen. Experiments utilising acarbose, a lysosomal (1----4)-alpha-D-glucosidase inhibitor, show that some blood glucose could arise in normal mammals from extra-hepatic tissue, by degradation of the glycogen in the lysosomal compartment.

Topics: Acarbose; Animals; Blood Glucose; Disease Models, Animal; Endopeptidase K; Glycogen; Glycogen Storage Disease Type VII; Glycoside Hydrolase Inhibitors; Lactates; Lysosomes; Phosphorylase Kinase; Pyruvates; Rats; Serine Endopeptidases; Trisaccharides

Thirty-two rabbits with monocular surgically induced keratoconjunctivitis sicca (KCS) underwent masked treatment for 12 weeks with 1 of 4 artificial tear solutions. Disease in each group of treated rabbits was compared with disease in untreated KCS controls. One of the solutions tested was a unique electrolyte-based formulation shown previously to preserve normal goblet-cell density after extended exposure in normal rabbits. Only the electrolyte-based solution decreased elevated tear osmolarity and sodium after 9 weeks of treatment (P less than 0.05). At 20 weeks, mean corneal glycogen and conjunctival goblet-cell density in eyes treated with the electrolyte-based solution increased significantly relative to untreated KCS controls (P less than 0.01). With the other three solutions, mean glycogen levels and goblet-cell densities were either decreased relative to untreated KCS controls (P less than 0.05) or were unchanged. The electrolyte-based solution is the first treatment to increase corneal glycogen and conjunctival goblet cells in a rabbit model of KCS.

Topics: Animals; Cell Count; Conjunctiva; Cornea; Disease Models, Animal; Electrolytes; Female; Glycogen; Hypotonic Solutions; Keratoconjunctivitis Sicca; Male; Ophthalmic Solutions; Osmolar Concentration; Rabbits; Random Allocation; Tears

The present study describes the structural changes in the gracile nucleus of the spontaneously diabetic BB rat. At 3-7 days post-diabetes, axons, axon terminals and dendrites showed electron-dense degeneration. Degenerating axons were characterized by swollen mitochondria, vacuolation, accumulation of glycogen granules, tubulovesicular elements, neurofilaments and dense lamellar bodies. Degenerating axon terminals consisted of an electron-dense cytoplasm containing swollen mitochondria, vacuoles and clustering of synaptic vesicles. These axon terminals made synaptic contacts with cell somata, dendrites and other axon terminals. Degenerating dendrites were postsynaptic to normal as well as degenerating axon terminals. At 1-3 months post-diabetes, degenerating electron-dense axons, axon terminals and dendrites were widely scattered in the neuropil. Macrophages containing degenerating electron-dense debris were also present. At 6 months post-diabetes, the freshly degenerating neuronal elements encountered were similar to those observed at 3-7 days. However, there were more degenerating profiles at 6 months post-diabetes compared to the earlier time intervals. Terminally degenerating axons were vacuolated and their axoplasm appeared amorphous. It is concluded that degenerative changes occur in the gracile nucleus of the spontaneously diabetic BB rat.

Topics: Animals; Axons; Brain Stem; Diabetes Mellitus; Disease Models, Animal; Glycogen; Intermediate Filaments; Male; Mitochondrial Swelling; Rats; Rats, Inbred BB; Vacuoles

Neonatal sepsis is a significant health problem. However, to our knowledge, the temporal substrates and insulin response to endotoxin have not been characterized in the young animal to guide the investigations of glucoregulation in septic shock in the newborn. We characterized the temporal response to endotoxin in the developing rat. Sprague-Dawley rats were given intraperitoneal Salmonella enteritidis endotoxin in high and low lethal doses to zero, ten and 28 day old rats. Mortality, temporal glucose, lactate, hepatic glycogen and insulin were monitored. Mortality experiments show the ten day old rat is 300 times as sensitive to endotoxin as the 28 day old rat. Plasma glucose concentration increased in the high mortality groups by 120 minutes in the zero and ten day old rats (102 +/- 4 milligrams per deciliter, 119 +/- 6 milligrams per deciliter, respectively, and by 60 minutes in the 28 day old rats (223 +/- 12 milligrams per deciliter). The plasma glucose level decreased to 52 +/- 3 milligrams per deciliter by 240 minutes in the ten day old and by 180 minutes to 99 +/- 8 milligrams per deciliter in the 28 day high mortality groups. Peak lactic acid levels in the high lethality groups were zero day 2.8 +/- 0.2 millimoles per liter in zero day old rats, 3.3 +/- 0.2 millimoles per liter in 28 day old rats. Glycogen in the liver decreased rapidly by 120 minutes in all age groups. Plasma insulin concentration did not elevate significantly in zero and ten day old rats. In the 28 day old rat, insulin concentration increased by 120 minutes to 52 +/- 17 microunits per milliliter. Insulin glucose ratios were also elevated in the 28 day old endotoxin treated rat, indicating hyperinsulinemia. Thus, temporal substrates and insulin responses to endotoxin differ with animal age.

Topics: Age Factors; Animals; Blood Glucose; Disease Models, Animal; Female; Glycogen; Insulin; Lactates; Liver; Monitoring, Physiologic; Polysaccharides, Bacterial; Pregnancy; Rats; Rats, Inbred Strains; Salmonella enteritidis; Shock, Septic; Time Factors

This study compares the metabolic and functional effects of three different models of ischemia in the immature heart. The intent was (1) to develop a model of energy-depleted and functionally depressed heart to be used in subsequent studies of myocardial protection and (2) to characterize the biochemical changes following different interventions. Forty-five minutes of normothermic global ischemia produced severe depletion of adenosine triphosphate and creatine phosphate (greater than 70%) but was associated with 85% +/- 10% recovery of left ventricular function. Postischemic functional depression (less than 30% recovery) could be produced by either (1) extending the ischemic duration to 60 minutes or (2) preceding 45 minutes of ischemia by 60 minutes of hypoxic stress (oxygen tension 25 to 30 mm Hg). Neither of these more severe interventions caused more profound depletion of adenosine triphosphate or creatine phosphate, but hypoxic stress produced marked tissue depletion of glutamate (52%) and aspartate (48%) before aortic clamping. Longer ischemia or preceding hypoxia led to greater myocardial accumulation of lactate (greater than 250 versus 104 mumol/gm dry weight) and succinate (18 versus 11 mumol/gm dry weight) during aortic clamping, p less than 0.05 versus 45 minutes of ischemia) and greater postischemic depression and amino acid (greater than 65% aspartate depletion) and carbohydrate (greater than 50% glycogen depletion) metabolism, p less than 0.05 versus simple ischemia. These findings suggest that more severe ischemic/hypoxic models are needed in immature hearts to produce functional depression, and the biochemical analyses suggest the characteristics of metabolic defects that must be corrected to resuscitate these hearts during surgical correction of congenital defects.

Topics: Adenosine Triphosphate; Amino Acids, Dicarboxylic; Animals; Carboxylic Acids; Coronary Circulation; Disease Models, Animal; Dogs; Glycogen; Lactates; Lactic Acid; Myocardial Reperfusion Injury; Myocardium; Phosphocreatine; Time Factors; Ventricular Function, Left

The contents of glycogen and ATP in the major cerebral arteries were examined in dogs undergoing subarachnoid haemorrhage (SAH). SAH was produced by a single injection of autologous arterial blood (1 ml/kg body weight) into the cisterna magna. Vertebral angiograms showed biphasic basilar arterial narrowings after the injection of blood: Early arterial narrowing occurred immediately after the injection and continued for a few hours. Late arterial narrowing occurred from Day 1 to Day 14 of post-SAH period, and recovered to the normal level on Day 21 of post-SAH period. The content of glycogen in the large pial arteries significantly decreased from Day 1 to Day 14 and returned to the control level on Day 21. The content of ATP in the large pial arteries also decreased from Day 1 to Day 7 and returned to the control level on Day 14. These results show that energy stores in the major cerebral arteries might be diminished during late arterial narrowing.

Topics: Adenosine Triphosphate; Animals; Basilar Artery; Cerebral Arteries; Disease Models, Animal; Dogs; Female; Glycogen; Male; Muscle, Smooth, Vascular; Radiography; Subarachnoid Hemorrhage; Time Factors

We compared acid alpha-glucosidase of acid maltase-deficient Japanese quails, an animal model of human late-onset glycogenosis type II, with that of normal controls. Antibody produced in a rabbit against acid alpha-glucosidase purified from chicken pectoral muscle cross-reacted with that of Japanese quails. The presence of a 110K and 98K form of acid alpha-glucosidase was confirmed in normal controls by immunoblotting. However the 98K form was absent in the affected quails. Subcellular distribution studies demonstrated that the 98K form, but not the 110K form, was localized in the lysosomes. This suggests that the 110K form is a precursor of the mature 98K form of acid alpha-glucosidase. In the affected quails, the 110K precursor is synthesized, but maturation to the 98K form does not occur or may be extremely deficient.

Topics: alpha-Glucosidases; Animals; Coturnix; Disease Models, Animal; Electrophoresis; Glucan 1,4-alpha-Glucosidase; Glycogen; Glycogen Storage Disease Type II; Immunoblotting; Lysosomes

We have continued our study of the tear film and ocular surface in our full KCS (keratoconjunctivitis sicca) rabbit model up to 52 weeks post-operatively. Tear film osmolarity remains elevated, conjunctival goblet cell density remains decreased, and the conjunctival epithelium remains abnormal. Corneal epithelial glycogen levels decreased progressively, and at 44 weeks post-operatively rabbits developed abnormal rose Bengal staining of the affected cornea that was shown to be associated with morphologic abnormalities at 52 weeks. Rabbits began rubbing the affected eye after the development of corneal staining. Our full KCS rabbit model demonstrates the features of the human disease.

Topics: Animals; Conjunctiva; Cornea; Disease Models, Animal; Epithelial Cells; Glycogen; Keratoconjunctivitis; Osmolar Concentration; Rabbits; Tears; Time Factors

The hepatoprotective effect of colchicine in a model of liver intoxication with galactosamine (GalN), 375 mg/kg, i.p., was studied in rats. At 0.5, 1, 3, 6, 18 and 24 h after GalN intoxication the following markers of liver damage were measured: serum activity of alanine aminotransferase, alkaline phosphatase, gamma-glutamyltranspeptidase, hepatic calcium and glycogen contents, liver lipoperoxidation, and liver plasma membrane activity of alkaline phosphatase, gamma-glutamyltranspeptidase and high-affinity Ca2+-ATPase. 24 h after GalN intoxication increases in serum levels of alanine aminotransferase, alkaline phosphatase and gamma-glutamyltranspeptidase were observed along with decreases in plasma membrane activities of alkaline phosphatase, gamma-glutamyltranspeptidase, and high-affinity Ca2+-ATPase. A sharp increase of lipoperoxidative processes measured as malondialdehyde production was also observed. Pretreatment of rats with colchicine 10 micrograms/rat/day p.o. for 7 days before GalN injection prevented partially the toxic effects of GalN. When a dose of 50 micrograms/rat/day for 7 days was given the drug prevented almost completely the damage induced by galactosamine, with the exception of glycogen and serum alkaline phosphatase that remained different from controls. Time-course experiments showed that malondialdehyde formation increased 30 min after intoxication while all other changes became apparent from 6 h after treatment, suggesting that lipoperoxidation may be a prerequisite for galactosamine-induced damage. The protection offered by colchicine was related to its capacity to inhibit lipoperoxidation. Histochemical findings paralleled the biochemical results. The possible role of lipoperoxidation in galactosamine-induced liver damage is discussed.

Topics: Alanine Transaminase; Alkaline Phosphatase; Animals; Calcium; Calcium-Transporting ATPases; Chemical and Drug Induced Liver Injury; Colchicine; Disease Models, Animal; Galactosamine; gamma-Glutamyltransferase; Glycogen; Lipid Peroxidation; Liver; Male; Rats; Rats, Inbred Strains

Cecal ligation and puncture (CLP) has been extensively used as a model of sepsis in adult rats. It is not known if the response to sepsis is similar in young and adult rats. This investigation was done to compare hemodynamic and metabolic alterations in young (four to six weeks of age, 60 to 90 grams) and adult (12 to 14 weeks of age, 270 to 340 grams) rats after CLP. In one series of experiments, survival rate was determined for 96 hours, and in other experiments, mean arterial blood pressure (MAP), heart rate (HR), white blood cell count, hematocrit, platelets, plasma glucose, lactate, amino acids, blood urea nitrogen (BUN), blood and peritoneal cultures and resting energy expenditure (REE) were determined eight and 16 hours after CLP. Levels of glycogen in liver and muscle were determined 16 hours after CLP. Mortality rate was similar in young and adult rats. MAP was stable throughout the course of sepsis, with no significant differences between the two groups of rats. HR was higher in young rats at all times studied. The adult rats became hyperglycemic after CLP while the young were hypoglycemic eight hours after CLP but normalized at 16 hours. Plasma lactate and BUN were similar in the two groups of rats, and no alterations were seen during sepsis. Both young and adult rats became hypoaminoacidemic after CLP. The phenylalanine to tyrosine ratio increased in a similar manner during sepsis in both experimental groups. REE was higher in young than in adult rats, but no significant changes were observed during the course of sepsis in either group.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Age Factors; Amino Acids; Animals; Cecum; Disease Models, Animal; Energy Metabolism; Glycogen; Hemodynamics; Ligation; Male; Peritoneal Cavity; Punctures; Rats; Rats, Inbred Strains; Sepsis; Time Factors

We tested the efficacy of various putative neuroprotective agents in the gerbil model of delayed neuronal death. The selective loss of anterior CA1 neurons of the hippocampus 4 days after 5 minutes of bilateral ischemia was complete in greater than 90% of the gerbils examined. We tested 11 agents for their ability to protect against neuronal loss. Only those agents that were associated with the GABAergic system exhibited protection and only when administered before the ischemic insult. The possibility that delayed neuronal death is the result of a primary defect in inhibitory neurotransmission is considered.

Topics: Animals; Brain Ischemia; Cell Survival; Disease Models, Animal; Female; gamma-Aminobutyric Acid; Gerbillinae; Glycogen; Hippocampus; Neurons; Time Factors; Tissue Distribution

There is a paucity of information on the significance of insulin on neonatal cerebral glucose metabolism. The effect of insulin on neonatal cerebral glucose uptake and cerebral cortical metabolic intermediates was investigated with the euglycemic hyperinsulinemic clamp in unanesthetized beagles during the first day of life. Insulin was infused at various rates to sustain an elevated steady state plasma insulin concentration in individual pups. Furthermore, blood glucose and 2-deoxyglucose levels were also maintained ("clamped") in a steady state by infusion of glucose and 2-deoxy-[14C]-glucose. Mean (+/- SD) plasma insulin levels were 20 +/- 12 and 2971 +/- 3386 (33-14330) microU/ml in control and hyperinsulinemic pups. Blood glucose concentration was 4.43 +/- 2.64 mM during basal periods and 4.54 +/- 2.87 mM during the clamp period in study pups. Basal fasting glucose utilization in study pups was 43.9 +/- 24 mumol/kg/min and increased to 60.9 +/- 35.2 mumol/kg/min (p less than 0.001) during hyperinsulinemia. Immediately after the euglycemic hyperinsulinemic clamp or fasting in control pups, the cerebral cortex was frozen to the temperature of liquid nitrogen. No differences were noted for any cerebral cortical intermediate between the two pup groups. In addition, there was no relationship between the cerebral intermediates concentration when analyzed as a function of plasma insulin levels. The uptake of cerebral 2-deoxyglucose was analyzed as a function of plasma insulin concentration (120-6900 microU/ml). Brain tissue demonstrated a positive linear relationship for 2-deoxyglucose uptake as a function of plasma insulin concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adenosine Triphosphate; Animals; Animals, Newborn; Cerebral Cortex; Citric Acid Cycle; Deoxy Sugars; Deoxyglucose; Disease Models, Animal; Dogs; Glycogen; Hyperinsulinism; Insulin; Liver; Muscles

To assess a suitable model for the study of the mechanisms of development of insulin resistance in vivo, liver and muscle glycogen levels (as a metabolic index of tissue insulin sensitivity) were investigated in rats with functioning islet cell adenomas induced by streptozotocin and nicotinamide. These rats have basal moderate hyperinsulinemia and hypoglycemia and show a remarkable increase in insulin secretion after glucose administration. Plasma glucagon concentrations are normal. Nevertheless, in tumor-bearing rats, a reduction of tissue glycogen stores occurs, related to plasma glucose concentrations, and liver glycogen fails to increase even after a glucose load. The lack of excess fat in tumor-bearing rats also suggests a certain insulin insensitivity of the adipose tissue and distinguishes this model of chronic hyperinsulinism from other reported models, such as genetically obese animals.

Topics: Adrenal Glands; Animals; Blood Glucose; Chronic Disease; Disease Models, Animal; Glucagon; Glycogen; Hyperinsulinism; Insulin; Insulin Resistance; Liver; Male; Muscles; Organ Size; Rats; Rats, Inbred Strains

Myocardial exogenous substrate preference was studied under conditions of increased plasma lactate concentration before and after a severe (halving of tissue ATP concentration, sixfold increase in tissue lactate concentration) but reversible (less than 1% necrosis on reperfusion) global ischaemic stress produced by continuous hypothermic electromechanical arrest of the heart of four hours' duration by aortic cross clamping and multidose potassium cardioplegia. Fatty acid oxidation was studied using 1-14C-palmitate under steady state conditions and under similar isovolumic fixed pressure conditions with the heart at a constant rate using a left ventricular intracavitary balloon. Exogenous free fatty acid oxidation during the pre-ischaemic period with an increased lactate concentration (3.9-5.8 mmol . litre-1) was 0.62(0.21) mumol . min-1 X 100 g-1 (mean (SEM)). This represented a mean of 32% of the total carbon dioxide produced in contrast to a post-ischaemia free fatty oxidation rate of 2.67(0.87) mumol . min-1 X 100 g-1, in the presence of even further increased plasma lactate concentrations (8.47-11.17 mmol . litre-1), representing a mean of 82% of the total carbon dioxide output. These data suggest that the substrate preference of the myocardium, under conditions of increased plasma lactate concentration, shifts to greater oxidation of exogenous free fatty acids after ischaemic stress.

Topics: Adenosine Triphosphate; Animals; Coronary Disease; Disease Models, Animal; Dogs; Fatty Acids, Nonesterified; Glycogen; Heart; Lactates; Myocardial Contraction; Myocardium; Oxygen; Phosphocreatine

Alcoholic cardiomyopathy, characterized by cardiac hypertrophy, was induced in young turkey poults with 5% ethanol. Ultrastructural features included accumulation of glycogen, swollen mitochondria, myofibrillar lysis, increased number of lysosomes, dilated sarcoplasmic reticulum and dense myofibers. Similarity of these alterations to those described in human alcoholic cardiomyopathy confirms the usefulness of the turkey poult as an animal model for this disease syndrome.

Topics: Animals; Cardiomyopathy, Alcoholic; Disease Models, Animal; Glycogen; Lysosomes; Male; Mitochondria, Heart; Myocardium; Myofibrils; Organ Size; Turkeys

To isolate and demonstrate the effect of insulin on pulmonary surfactant in vivo, islet cell hyperplasia and hyperinsulinemia were produced in fetal rabbits by the litter reduction technique without concomitant hormonal or metabolic changes in mother or fetus. This produced fetuses which were heavier than controls (37.1 vs. 31.5 g), with two-fold higher insulin levels (48.1 vs. 24.3 microU/ml). The fetal weight correlated directly with the insulin level, while the L/S ratio was found to correlate inversely with the insulin level. This inhibitory effect may be mediated by any of several mechanisms which await further investigation.

Topics: Animals; Body Weight; Disease Models, Animal; Female; Fetus; Glucose; Glycogen; Insulin; Macaca mulatta; Phosphatidylcholines; Pregnancy; Pulmonary Surfactants; Rabbits; Rats; Sphingomyelins

The pathology of canine glycogen storage disease type II (acid alpha-glucosidase deficiency, GSD II) was studied in three genetically related Lapland dogs and compared to the pathology of human GSD II (McKusick 23230). Canine GSD II closely parallels the infantile form of the human disease, except for the presence of oesophageal dilatation. Generalized glycogen storage particularly affected muscular tissues (skeletal, oesophageal, cardiac and smooth muscle). The altered cells showed glycogen accumulation in the cytosol and in autophagic membrane-bound vacuoles (glycogenosomes). They also showed increased acid phosphatase activity consistent with the lysosomal nature of this storage disorder. The cytopathology in canine and human GSD II appears to evolve from segregation of glycogen during regular cellular autophagy, phagolysosomal accumulation of the undigested glycogen, and eventually rupture of distended glycogenosomes. This study indicates that the usefulness of canine GSD II as an animal model of human disease, extends to the area of pathogenesis.

Topics: Acid Phosphatase; Animals; Brain; Cytoplasm; Disease Models, Animal; Dogs; Esophagus; Female; Glycogen; Glycogen Storage Disease; Glycogen Storage Disease Type II; Humans; Kidney; Liver; Male; Microscopy, Electron; Muscle, Smooth; Muscles; Myocardium; Neurons; Spinal Cord; Vacuoles

It has been reported that sand rats, naturally feeding on low-caloric-value plants containing a high concentration of salt, become obese and develop hyperglycemia when fed on a standard laboratory diet. The aim of this study was to examine the long-term effects of a synthetic-chow diet on the metabolic pattern of the diabetic syndrome in a large group of sand rats. While a few animals had a fulminant reaction with markedly decreased glucose tolerance, low plasma insulin levels, and death within 3-4 wk, most sand rats developed obesity and elevated plasma insulin levels. From the third month and forward, 40% of sand rats presented with a diabetic syndrome with hyperinsulinemia, hyperglycemia, markedly decreased glucose tolerance, and insulin resistance. This diabetic syndrome can be compared with maturity-onset (type II) diabetes. When this synthetic-chow diet was given for more than 6 mo, the majority of animals lost considerable weight and showed a major depletion of fat stores. Serum immunoreactive insulin levels fell, while blood glucose rose to above 500 mg/dl with glycosuria and ketonuria. The elevated triglyceride content of plasma and the lipid deposits in the liver were greatly augmented, and no glycogen was present. Animals developed frank insulin-dependent diabetes, and diabetic animals not treated with insulin died in diabetic coma with presumed ketoacidosis. The disease was essentially confined to sand rats showing abnormal glucose tolerance, even before eating laboratory chow. This observation suggests a genetic factor. Thus, the sand rat appears to be a potentially interesting model for investigation of both maturity-onset and insulin-dependent diabetes.

Topics: Animal Feed; Animals; Arvicolinae; Blood Glucose; Body Weight; Diabetes Mellitus; Disease Models, Animal; Energy Intake; Female; Glucose Tolerance Test; Glycogen; Glycosuria; Insulin; Ketone Bodies; Liver; Male

Topics: Animals; Disease Models, Animal; Dogs; Female; Glycogen; Joint Diseases; Knee Injuries; Ligaments, Articular; Male; Menisci, Tibial; Sulfates

Topics: Adenosine Triphosphate; Animals; Disease Models, Animal; Fructosediphosphates; Glycogen; Glycolysis; Hexosediphosphates; Lactates; Lactic Acid; Male; Muscle Contraction; Muscle Cramp; Muscles; Myoglobinuria; Phosphocreatine; Physical Exertion; Rats; Rats, Inbred Strains

Topics: Animals; Disease Models, Animal; Glucose; Glycogen; Glycogen Storage Disease; Iodoacetates; Muscles; Rats

The effects of fasting on lipid and carbohydrate metabolism and plasma insulin and glucagon levels were compared in lean and obese Zucker rats. Sixteen-month-old female and male rats were fasted for periods of 2, 4, 6 and 12 days. Fasting produced significant decreases in hepatic rates of lipid, cholesterol, and glycogen synthesis, as well as circulating levels of triglycerides, cholesterol, phospholipids, and insulin. Significant increases in hepatic lipid levels and serum free fatty acids were noted. When compared to lean rats, obese rats had elevated rates of hepatic lipid and glycogen synthesis, hepatic lipid and glycogen stores, serum triglycerides, cholesterol, phospholipids, and plasma insulin. Lean rats had higher plasma glucagon levels. Sex differences in several parameters were observed. Females demonstrated higher levels of lipid and cholesterol synthesis and serum free fatty acids, whereas serum cholesterol levels and hepatic glycogen stores were higher in males. Following a 12-day fast, carcass fat and protein content were decreased in both lean and obese rats, but the obese animals maintained an obese body composition. It is concluded that fasting results in qualitatively similar metabolic and hormonal changes in both lean and obese rats, but that abnormalities in carbohydrate and lipid metabolism persist in obese rats even after a 12-day fast.

Topics: Animals; Carbohydrate Metabolism; Cholesterol; Disease Models, Animal; Fasting; Fatty Acids, Nonesterified; Female; Glucagon; Glycogen; Insulin; Lipid Metabolism; Liver; Male; Obesity; Phospholipids; Rats; Sex Factors; Triglycerides

An experimental protein-calorie malnutrition was produced in weanling Sprague-Dawley rats. The model resembles human malnutrition with respect to weight loss, inanition, angular stomatitis, anemia, lymphopenia, hypoproteinemia with hypoalbuminemia, and marked thymic involution. In addition, systemic invasion by gram-negative rods was documented. However, no edema was produced, and animals did not survive for longer than six weeks on the protein-deficient diet. One percent glycogen was found to be a satisfactory nonprotein stimulus for induction of a peritoneal exudate consisting primarily of young macrophages. Electron microscopy showed that morphologic events of phagocytosis and degranulation proceeded normally in macrophages from protein-deficient animals. In addition, cell surface receptors for IgG were preserved under these experimental conditions. These data indicate that weanling rats may be employed as a small animal model for servere, fulminant protein-calorie malnutrition in humans.

Topics: Animals; Ascitic Fluid; Binding Sites, Antibody; Body Weight; Disease Models, Animal; Glycogen; Hexosephosphates; Immunoglobulin G; Macrophages; Male; Neutrophils; Phagocytosis; Protein-Energy Malnutrition; Rats; Receptors, Antigen, B-Cell

One hundred-twenty Sprague-Dawley rats were shocked at 60 torr for 60 minutes and at the end of this period shed blood was reinfused. The animals were divided into three groups at random. These groups were either treated by N saline or glucose in N saline or glucagon in N saline. Glucagon treatment resulted in increased liver and muscle glucose-glycogen stores in the late period following shock. This was associated with a decrease in liver pyruvate and lactate and improved survival. It appears that glucagon more favorably affects the response to shock in this model than does treatment with glucose or saline.

Topics: Animals; Disease Models, Animal; Female; Glucagon; Glucose; Glycogen; Liver; Male; Muscles; Rats; Shock, Hemorrhagic; Time Factors

Effects of insulin (1 mU/ml) on diaphragms removed from older-obese (70--110 days, 350--520 g) male Sprague-Dawley rats were compared to responses on muscle removed from younger-lean (27--36 days, 80--150 g) animals. Insulin antagonism on glucose transport (2DG uptake), glucose uptake, glycogen synthesis, glycolysis (lactate production), and glucose oxidation was demonstrated in tissue from the older-obese rats. Extracellular water spaces (measured with inulin-H3) were significantly decreased in these tissue. To determine if insulin antagonism of glucose transport could be secondary to inhibition of a rate-limiting reaction in the Embden-Meyerhof pathway with a subsequent negative feedback on transport, both tissue levels of glycolytic intermediates and oxidation of intracellular lipids were measured. No free intracellular glucose was found in diaphragms from either group of rats. Levels of G-6-P, F-6-P, F-1, 6-diP, PEP, and pyruvate were all lower in muscle from the older-obese animals. Incorporation of C14-FFA into tissue TG was slightly, but significantly, lower in this same tissue. Oxidation of intracellular TG and PL was similar in the two groups. In conclusion, diaphragms from older-obese rats manifest insulin antagonism of glucose transport that is probably responsible for the diminished hormonal effect on glucose uptake and the intracellular pathways of glycogen synthesis, glycolysis, and glucose oxidation. This inhibition of insulin action cannot be accounted for by changes in glycolytic intermediates causing a negative feedback on transport or enhanced lipid oxidation and therefore should be considered primary. The relative effects of age and obesity will need to be evaluated in future studies.

Topics: Aging; Animals; Biological Transport, Active; Deoxyglucose; Diaphragm; Disease Models, Animal; Glucose; Glycogen; Glycolysis; Insulin; Insulin Resistance; Lactates; Lipid Metabolism; Male; Muscle Development; Obesity; Rats

Topics: Acetate-CoA Ligase; Alcohol Oxidoreductases; Alcoholism; Aldehyde Oxidoreductases; Animals; Cardiomyopathies; Cholesterol; Creatine Kinase; Diet; Disease Models, Animal; Ethanol; Glycogen; Humans; L-Lactate Dehydrogenase; Lipid Metabolism; Male; Mice; Mitochondria, Muscle; Myocardium; Triglycerides

An attempt was made to determine the effect of hypothermic potassium cardioplegia (35 mEq of potassium chloride) on the hypertrophic ventricle. Puppies with induced left ventricular hypertrophy were divided into four groups and studied after one hour on global ischemia. Myocardial adenosine triphosphate (ATP) was best preserved in the hypothermically perfused groups and correlated well with measurements of coronary sinus creatine phosphokinase (CPK). In Groups 1 and 2 (anoxic arrest at 37 degrees C and KC1 perfusion at 37 degrees C), CPK at 30 minutes of reperfusion was 1,031 and 198 IU, respectively, compared to 35 IU in Group 3 (KC1 perfusion at 4 degrees C) and 44 IU in Group 4 (Ringer's lactate at 4 degrees C). Myocardial injury was milder in Groups 3 and 4 regardless of whether potassium chloride was added. It is apparent that hypothermic perfusion of a hypertrophic ventricle was the major factor in myocardial preservation, as determined by myocardial ATP and coronary sinus CPK.

Topics: Adenosine Triphosphate; Animals; Cardiomegaly; Creatine Kinase; Disease Models, Animal; Dogs; Electrocardiography; Glycogen; Heart Arrest, Induced; Hypothermia, Induced; Lactates; Myocardial Contraction; Myocardium; Organ Size; Perfusion; Phosphocreatine; Potassium Chloride

This study examines the effect of maternally injected glucocorticoid on the pattern of hypoglycemia exhibited by rat pups with intrauterine growth retardation (IUGR). The majority of surgical procedures designed to produce small-for-gestational age (SGA) newborns for biochemical studies were carried out on days 18 and 19 of gestation because of favorable vields of pups with IUGR at those operative days. At birth, normal controls showed a mean +/- SE plasma glucose value of 63 +/- 2 mg/dl; mean glucose for the group with IUGR was significantly lower at 43 +/- 2 mg/dl. There was a further decrease in the plasma glucose concentration of pups with IUGR at 2-4 hr of age, whereas values in the control littermates did not fall during this interval. Through the first 2 hr of neonatal life, 46% of the pups with IUGR exhibited plasma glucose values less than 40 mg/dl, whereas only 18% of the control littermates manifiested hypoglycemia. During the 2-4-hr interval, the incidence of hypoglycemia in animals with IUGR increased to 91%; however, the incidence in control remained at 18% from 2-4 hr and fell to 4% at 4-6 hr of age. At birth, the pups with IUGR had a lower mean liver weight compared to their control littermates, but glycogen concentration of liver was similar to the control mean +/- SE of 25.7 +/- 1.8 (IUGR = 22.2 +/- 1.3 mg/g wet weight). Total hepatic glycogen stores, however, were markedly lower in dysmature rat pups (IUGR = 2.96 +/- 0.17 mg; control = 7.23 +/- 0.43 mg). Concentrations of plasma glucose at birth of individual control and IUGR animals were found to correlate significantly (r = 0.64, p less than 0.001) with total liver glycogen content. The decline in plasma glucose values in pups with IUGR was not present in animals whose dams received glucocorticoid injection 24 and 48 hr before delivery. At 4-6 hr of age, for instance, the mean plasma glucose concentration in the corticoid-treated IUGR group (70.1 +/- 6.9 mg/dl) approximated that of the control group. Instead on the 91% incidence of hypoglycemia noted in the nontreated dysmature pups, an incidence of 55% was found at 2-4 hr of age in offspring of mothers given glucocorticoid. At 4-6 hr, the treated group showed an incidence of 18% compared to a 67% figure in the nontreated IUGR animals. The concentration of liver glycogen in these animals also differed in that the treated IUGR pups showed significantly higher values (26.9 +/- 1.7 mg/g wet weight, mean +/- SE) than nontreated progeny. I

Topics: Animals; Animals, Newborn; Blood Glucose; Disease Models, Animal; Female; Fetus; Glucocorticoids; Glycogen; Hypoglycemia; Liver; Organ Size; Pregnancy; Rats

Topics: Animals; Disease Models, Animal; Glycogen; Hyperglycemia; Hyperinsulinism; Liver Glycogen; Male; Muscles; Myocardium; Phenformin; Rats

Insertion of a flow pump into the Langendorff retrograde perfusion apparatus has permitted the production of stable, graded ischemia in hearts whose hemodynamic and metabolic response may be evaluated. Ventricular pressures were monitored with a modified balloon and catheter-tip manometer system, and oxygen consumption , lactate and glucose metabolism, and tissue high-energy phosphate stores measured. A 15-min stabilization period in 56 paced hearts was followed by 15 min of either full, 40, 30, 20, or 10% coronary flow, after which the ventricular tissue was freeze-clamped for tissue assay. Tissue creatine phosphate fell progressively from 23.7 in full flow hearts to 9.9 mumol/g dry wt after 90% reduction in flow. This was accompanied by a graded reduction in ATP from 20.3 to 14.0 mumol/g dry wt and a rise in AMP from 1.1 to 2.6 mumol/g dry wt. Tissue lactate rose progressively from 22.3 to 60.1 mumol/g dry wt. Hemodynamic function correlated with coronary flow. This preparation offers an opportunity to study pharmacological and metabolic interventions in ischemic heart disease.

Topics: Adenosine Diphosphate; Adenosine Monophosphate; Adenosine Triphosphate; Animals; Coronary Circulation; Coronary Disease; Disease Models, Animal; Glucose; Glycogen; Hemodynamics; In Vitro Techniques; Lactates; Male; Myocardial Contraction; Myocardium; Oxygen Consumption; Phosphocreatine; Rats

Thirteen of 31 Belgian Landrace pigs developed malignant hyperthermia (MH) after breathing halothane. A short period of exercise 1 h before the administration of the triggering agent increased the incidence of the syndrome to 100% in eight similar pigs. Clinical symptoms were more marked and developed more rapidly in the exercised pigs. All the reacting pigs became typically acidotic, developed rigor and died. Serum Na+, K+, Ca2+, c.p.k., l.d.h. and protein concentrations were increased to a variable extent during the reaction and there was an increase in p.c.v. also. No hyperglycaemia was detected in pigs which were rested before receiving halothane. Four of the eight exercised pigs became markedly hyperglycaemic and plasma noradrenaline increased to higher values. Phosphocreatine and ATP decreased to low values and lactate increased in the muscles of all pigs which reacted. At the time of death, muscle glycogen had decreased significantly in the rested, but not in the exercised, MH pigs.

Topics: Animals; Blood Glucose; Calcium; Creatine Kinase; Disease Models, Animal; Glycogen; Halothane; Heart; Isoenzymes; L-Lactate Dehydrogenase; Lactates; Malignant Hyperthermia; Muscles; Norepinephrine; Physical Exertion; Respiration; Sodium; Stress, Physiological; Swine; Swine Diseases

The effects of metabolic accumulation on myocardial metabolism during global heart oxygen deprivation were evaluated in a working in situ swine heart preparation with controlled total coronary blood flow. Myocardial oxygen consumption was depressed to a similar extent by either reducing total coronary flow 60 per cent (ischemia, low coronary perfusion) in 10 swine or by decreasing coronary perfusate PO2 to 30 mm. Hg at normal flows (hypoxemia, high coronary perfusion) in 13 swine. Compared with findings in 13 control hearts, ischemia significantly (p less than 0.05) decreased myocardial oxygen consumption (640 to 390 mumole per hour per gram), glucose uptake (185 to 16 mumole per hour per gram), and free fatty acid consumption (32 to 17 mumole per hour per gram). ttissue levels of glycogen, creatine phosphate, and adenosine triphosphate (tatp) were significantly reduced (p less than 0.005), and tissue lactate, adenosine diphosphate (ADP), and adenosine monophosphate (AMP) were increased (p less than 0.001). During hypoxemia, glucose uptake was increased (240 mumole per hour per gram) and free fatty acid consumption was somewhat less depressed (19 mumole per hour per gram). Creatine phosphate and ATP were higher than with ischemia (p less than 0.01), and lactate, ADP, and AMP accumulations were less (p less than 0.01). Thus, in the period immediately following myocardial oxygen deprivation, inadequate coronary perfusion caused greater metabolic buildup which inhibited myocardial substrate utilization and energy production. High coronary perfusion, even though the perfusate was unoxygenated, was associated with greater preservation of substrate utilization, higher levels of high-energy phosphates, less accumulation of metabolic products, and a longer survival. These data suggest a critical role of coronary perfusion in protecting myocardial metabolism in the immediate period following global heart hypoxia.

Topics: Adenosine Diphosphate; Adenosine Monophosphate; Adenosine Triphosphate; Animals; Coronary Disease; Disease Models, Animal; Female; Glucose; Glycogen; Heart; Hemodynamics; Hypoxia; Lactates; Male; Myocardial Revascularization; Myocardium; Oxygen Consumption; Phosphocreatine; Swine

Severe cardiac hypertrophy has been produced experimentally in rats by long-term, low-dose treatment with tri-iodothyroacetic acid. The dose used was insufficient to cause any apparent systemic or metabolic effect. It is suggested that similar iodinated substances in the blood in man, resulting from normal or abnormal thyroid hormone catabolism, may be causally related to some forms of cardiomyopathy.

Topics: Acetates; Acid Phosphatase; Alkaline Phosphatase; Animals; Cardiomegaly; Disease Models, Animal; Glycogen; Heart; Heart Ventricles; Mitochondria, Muscle; Myocardium; Organ Size; Rats; Succinate Dehydrogenase; Triiodothyronine

The effects of infusions of glucose, insulin and potassium (GIK) on the heart tissue metabolic changes found in adult baboons 60 min after coronary artery ligation were studied. Biopsies taken from 11 baboons without coronary artery ligation gave control values. A second group of 46 baboons had coronary artery ligation. A third group of 17 baboons received an infusion of KCl after coronary artery ligation. A fourth group of 26 baboons received infusion of GIK. Coronary artery ligation resulted in the expected fall of ATP, creatine phosphate, glycogen, tissue (K+/Na+) ratio, and tissue pH, and rise of inorganic phosphate, lactare, lactate/pyruvate ratio and alpha-glycerophosphate in the infarction zones. Compared with ligation, additional infusions of GIK approximately doubled the contents of creatine phosphate and glycogen in the infarct zones, increased the content of ATP in the central infarct zone, and decreased the content of inorganic phosphate in the peripheral infarct zone. Other GIK effects were that the tissue (K+/Na+) ratio rose in the peripheral infarct zone, and the content of both glycogen and lactate rose in the peri-infarct and non-ischemic zones; the pH of tissue homogenates did not decrease. KCl infusions had few effects compared with the ligation group. GIK infusions exerted a beneficial effect when compared with infusions of KCl in that tissue creatine phosphate rose in the peripheral infarct and nonischemic zones; the tissue K+/Na+ ratio rose in the peripheral infarct, peri-infarct, and nonischemic zones; and the lactate/pyruvate ratio fell in the infarct zone. It is proposed that GIK counteracted early tissue metabolic deterioration in the infarcting baboon heart.

Topics: Adenosine Triphosphate; Animals; Coronary Vessels; Creatine; Disease Models, Animal; Dogs; Female; Glucose; Glycogen; Heart; Hydrogen-Ion Concentration; Infusions, Parenteral; Insulin; Male; Myocardial Infarction; Myocardium; Papio; Potassium; Potassium Chloride; Time Factors

Topics: Adenosine Triphosphate; Animals; Coronary Disease; Depression, Chemical; Disease Models, Animal; Dogs; Glucosephosphates; Glycogen; Glycolysis; Heart; Lactates; Myocardium; Nitroglycerin; Phosphocreatine; Phosphorylases

An in situ working swine heart preparation is described in which total coronary perfusion was controlled. At normal rates of coronary flow, oxygen, glucose, and fatty acid utilization were stable for at least a 60-min perfusion period. With a 50% reduction in coronary flow, oxygen and glucose consumption were reduced during 30 min of perfusion and fatty acid extraction was lower at the end of 30 min. Glycogen utilization was increased, but tissue levels of creatine phosphate, ATP, and lactate were similar to those in hearts receiving normal flow. With a 60% reduction in coronary flow, uptake of oxygen, glucose, and fatty acids were further decreased. Tissue levels of high-energy phosphates and glycogen were decreased and ADP, AMP, and lactate increased. Mechanical performance progressively deteriorated in these hearts, and ventricular fibrillation developed after about 20 min (19.8 plus or minus 3.0 min). The data indicate that this preparation is suitable for the study of myocardial metabolism during mild and severe ischemia and may be useful for the evaluation of pharmacological interventions designed for the treatment of myocardial ischemia.

Topics: Adenosine Diphosphate; Adenosine Monophosphate; Adenosine Triphosphate; Animals; Coronary Circulation; Coronary Disease; Disease Models, Animal; Energy Metabolism; Fatty Acids; Female; Glucose; Glycogen; Heart; Lactates; Male; Myocardium; Oxygen Consumption; Regional Blood Flow; Swine; Ventricular Fibrillation

Regional contraction of ischemic anterior and normal lateral left ventricular myocardium was measured with isometric force gauges after 5, 10, 15, and 20 minutes of anterior descending coronary artery occlusion-each followed by 10 minutes of reperfusion. Multiple myocardial biopsies of both regions were taken at these same intervals and examined by electron microscopic techniques. Mean contraction of the ischemic area fell significantly in 15 to 30 seconds and returned to an average of 68, 51, 40, and 28 per cent, respectively, after 5, 10, 15, and 20 minutes of ischemia. Simultaneously, focal morphologic changes were detected after 5 and 10 minutes, were more clear and widespread at 15 minutes, and diffuse and unequivocal at 20 minutes, when return of local contraction was minimal. The changes of myocardial morphology in the ischemic area as seen by electron microscopy were: reduced content of glycogen granules and mitochondrial changes. The latter began to appear at 5 minutes and consisted of swelling, disruption of cristae, and reduction of matrix. This study indicates a qualitative correlation between ultrastructural changes in regionally ischemic myocardium and diminished regional function in the intact heart. At 5 and 10 minutes the mitochondrial changes were focal, requiring multiple samples, while at 15 and 20 minutes they became more widespread, making the occasional sample more representative.

Topics: Animals; Coronary Disease; Disease Models, Animal; Glycogen; Heart; Histocytochemistry; Microscopy, Electron; Mitochondria, Muscle; Mitochondrial Swelling; Myocardial Contraction; Myocardium; Swine; Time Factors

A major concern in the use of neural prostheses is whether electrical stimualtion can cause irreversible damage to neurons. The Neural Damage Model was devised to study the problem and to provide guidlines. The cerebral cortex of cats was stimulated continuously for 36 hours with balanced, biphasic waveforms. The charge per phase, charge density and current density were varied in 16 separate tests. Of these stimulus parameters the charge per phase was more closely correlatable with neuronal damage than charge density and current density. Furthermore, the findings in this study suggest that current flow is more important than electrochemical reactions in causing neural damage. Correlation between blood-brain barrier (BBB) breakdown and neuronal damage was valid only in the group of animals sacrificed immediately following stimulation. The BBB is restored within one month following electrical injury. Convulsive seizures occurred in all but one of the animals during electrical stimulation. A technique for localizing the electrode sites at autopsy and in the microscopic sections is described.

Topics: Animals; Astrocytes; Blood-Brain Barrier; Brain Injuries; Cats; Cerebral Cortex; Disease Models, Animal; Electric Stimulation; Glycogen; Neurons; Seizures

After experimental ureterotomy in mice, the changes which occurred in cerebral metabolism were studied. A significant increase in the cerebral glucose and glycogen level as well as of degradation power was noticed 25 hours after the operation. The level of lactic acid production in the same period of renal insufficience indicated a gradual decreasing tendency. These results as well as further details are discussed with regard to the underlying disturbances.

Topics: Acute Kidney Injury; Adenosine Triphosphate; Animals; Anuria; Brain; Disease Models, Animal; Energy Metabolism; Glucose; Glycogen; Lactates; Male; Mice; Phosphocreatine; Time Factors; Urea

After local complete ischemia at normothermia of 60, 100, 140, and 180 min duration the status of the adenylic acid-creatine phosphate system in the canine myocardium recovered to 98, 85, 74, and 30 percent of the control values, whereas glycogen was restored even more. In the infarcted myocardium the extent of alterations of the metabolic status was a function of the residual blood flow. Deviations from a regular metabolic status developed if the blood flow dropped below about 35 ml/min/100 gm. This critical flow rate is expected to vary with the energy requirement of the heart, but it is in keeping with results obtained by Rudolph and coworkers (personal communication) who found that patients with a myocardial blood flow below 30 ml/min/100 gm had a life expectancy of less than 1 month. In the nonaffected myocardium, both in experiments with local complete ischemia and in experiments with infarction, the metabolic status was always within normal ranges. This is in contrast to results published by Gudbjarnason (1971/1972) and Gudbjarnason, Puri, and Mathes (1971), who found that in noninfarcted myocardium tissue levels of ATP and creatine phosphate decreased to about 50 percent of the control values and that there was no restoration to normal values within 10 days after infarction.

Topics: Adenosine Monophosphate; Animals; Coronary Disease; Creatine; Disease Models, Animal; Dogs; Glycogen; Heart Ventricles; Lactates; Myocardial Infarction; Myocardium; Phosphocreatine; Time Factors

The glycogen contents of 121 rabbit brains having different levels of hypoxia were determined, calculation being in mg% of glucose per g of brain. It was possible to observe significant reductions in carbohydrate content under conditions of acute and chronic hypoxia. Moderate prepartum accumulation of glycogen in untreated rabbit brains is likely. Chronic reduction in reserve fuel resulted in deficient development of the brain, as is clearly shown by brain weight determinations. This enables a parallel between this condition and intrauterine dystrophia.

Topics: Animals; Animals, Newborn; Brain; Disease Models, Animal; Female; Fetal Hypoxia; Glycogen; Hypoxia; Organ Size; Pregnancy; Rabbits

The effects of hormonally-prolonged gestation on the rabbit placenta were studied in 9 female rabbits. Chlormadinone (a progestagen) was injected im at .23 mg/day beginning with the first day of gestation. 5 of the treated rabbits were killed on the 34th day of gestation and 4 on the 35th day; there were no spontaneous births. In the placentas taken from the treated animals, a transient over-differentiation of the fetal peripheral vascular system and, finally, extensive circulation disorders in the maternal sinus were observed, leading to the formation of infarction placentas. The big fetal vessels were found to be greatly stenosed as a result of intimal proliferations. The maternal decidual arteries had undergone parietal and obturating thromboses. The decidua basalis showed signs of premature detachment of the placenta. The data on prolonged gestation in rabbits are compared with results of similar experiments in rats, and on those available on human over-gestation. As regards the morphological picutre of the placenta, the model of experimentally prolonged gestation in the rabbit appears to be excellently suited for the study of chronic placental insufficiency in human beings.

Topics: Animals; Chlormadinone Acetate; Disease Models, Animal; Female; Gestational Age; Glycogen; Placenta; Placenta Diseases; Pregnancy; Pregnancy, Prolonged; Rabbits; Staining and Labeling

Topics: Animals; Cricetinae; Diabetes Mellitus; Diabetic Ketoacidosis; Diabetic Nephropathies; Diabetic Retinopathy; Disease Models, Animal; Female; Glucose; Glycogen; Glycosuria; Histocytochemistry; Islets of Langerhans; Kidney; Male; Retina

Topics: Animals; Antigens; Basement Membrane; Body Weight; Capillaries; Diabetic Retinopathy; Disease Models, Animal; Endothelium; Eye; Glycogen; Hyperglycemia; Inclusion Bodies; Injections, Intravenous; Insulin; Microscopy, Electron; Mitochondria; Plasma Cells; Polyuria; Rats; Retina; Retinal Vessels; Streptozocin; Time Factors; Trypsin

Topics: Adenylyl Cyclases; Animals; Blood Glucose; Carbon Radioisotopes; Diet; Disease Models, Animal; Epinephrine; Fasting; Fatty Acids, Nonesterified; Glycogen; Glycogen Synthase; Glycolysis; Heart Rate; Insulin; Lactates; Male; Myocardium; Nephrectomy; Perfusion; Phosphoric Diester Hydrolases; Phosphorylases; Rats; Transferases; Uremia

Topics: Adipose Tissue; Animals; Blood Glucose; Dietary Fats; Disease Models, Animal; Epididymis; Fatty Acids; Glucagon; Glucose; Glycogen; In Vitro Techniques; Insulin; Lipids; Liver; Male; Muscles; Obesity; Pancreas; Phospholipids; Rats; Rats, Inbred Strains; Triglycerides

Topics: Actomyosin; Animal Nutritional Physiological Phenomena; Animals; Carbon Radioisotopes; Deficiency Diseases; Disease Models, Animal; DNA; Female; Glycogen; Kwashiorkor; Leucine; Lipid Metabolism; Liver; Mitochondria; Muscle Proteins; Myocardium; Myofibrils; Organ Size; Polyribosomes; Protein Biosynthesis; Rats; RNA; Threonine

Topics: Animals; Cardiac Output; Coronary Disease; Disease Models, Animal; Dogs; Edema; Electrocardiography; Endoplasmic Reticulum; Glycogen; Heart; Hypoxia; Microscopy, Electron; Mitochondrial Swelling; Myocardial Revascularization; Myocardium; Myofibrils; Thoracic Arteries

Topics: Adenosine Triphosphate; Animals; Carbohydrate Metabolism, Inborn Errors; Disease Models, Animal; Fructose; Fructosephosphates; Glucose; Glycogen; Kinetics; Lactates; Liver; Mice; Nucleotidyltransferases; Phosphorylases; Rabbits

Topics: Animals; Brain; Carbon Monoxide Poisoning; Disease Models, Animal; Female; Glycogen; Glycogen Synthase; Male; Microscopy, Electron; Neuroglia; Purkinje Cells; Rats; Staining and Labeling

Topics: Animals; Antigens; Blood Glucose; Carbon Dioxide; Chlorides; Diabetes Mellitus, Experimental; Diabetic Coma; Diabetic Ketoacidosis; Disease Models, Animal; Fatty Acids, Nonesterified; Glycogen; Hydrocortisone; Insulin; Ketone Bodies; Liver; Male; Osmolar Concentration; Potassium; Rats; Sodium; Urea

Topics: Acetates; Adenosine Diphosphate; Adenosine Triphosphate; Amino Acids; Animals; Carbohydrate Metabolism; Carbon Isotopes; Disease Models, Animal; Glucose; Glycogen; Lactates; Lipid Metabolism; Liver; Liver Glycogen; Lung; Muscles; Myocardium; Penicillin G; Pneumococcal Infections; Proteins; Pyruvates; Rabbits; Sepsis; Streptococcus pneumoniae

The effects of glucose-insulin-potassium (GIK) on cardiac ultrastructure following acute experimental coronary occlusion were studied in dogs. Epicardial ST segment elevations at multiple sites on the anterior surface of the left ventricle 15 minutes after ligation of the left anterior descending coronary artery were used to predict infarct development. Biopsies removed from sites of known ST segment elevation were examined with the electron microscope, and the degree of injury was correlated with the ST segment elevation. The animals receiving GIK showed significantly less necrosis than was seen in dogs with occlusion alone at corresponding levels of ST segment elevation. Other evidence suggesting a beneficial effect of GIK was the presence of a fibrillar material in several biopsies from the treated animals, which may indicate the regeneration of myofilaments.

Topics: Animals; Arteries; Biopsy; Chromatin; Coronary Vessels; Disease Models, Animal; Dogs; Drug Combinations; Electrocardiography; Glucose; Glycogen; Heart Ventricles; Histological Techniques; Infusions, Parenteral; Insulin; Ligation; Microscopy, Electron; Mitochondria, Muscle; Mitochondrial Swelling; Myocardial Infarction; Myocardium; Myofibrils; Potassium

Topics: Acute Disease; Animals; Cytoplasm; Cytoplasmic Granules; Diabetes Mellitus; Disease Models, Animal; Endoplasmic Reticulum; Glycogen; Guinea Pigs; Islets of Langerhans; Microscopy; Microscopy, Electron

Topics: Animals; Coronary Circulation; Disease Models, Animal; Dogs; Extracorporeal Circulation; Glycogen; Heart Arrest, Induced; Heart Diseases; Heart Ventricles; Histocytochemistry; Ischemia; Magnesium Sulfate; Microscopy, Electron; Myocardium; Perfusion; Postoperative Complications; Time Factors

Topics: Acid-Base Equilibrium; Adenosine Triphosphate; Animals; Cerebral Cortex; Disease Models, Animal; Energy Metabolism; Glucose; Glycogen; Lactates; Oxygen Consumption; Pyruvates; Rats; Subarachnoid Hemorrhage

Topics: Alcoholic Intoxication; Animals; Blood Glucose; Cardiomyopathies; Disease Models, Animal; Ethanol; Fatty Acids, Nonesterified; Glycogen; Humans; Injections, Intraperitoneal; Lactates; Mitochondria; Myocardium; Statistics as Topic

Topics: Animals; Animals, Newborn; Asphyxia Neonatorum; Disease Models, Animal; Female; Glucosephosphate Dehydrogenase; Glucosyltransferases; Glycogen; Histocytochemistry; Humans; Infant, Newborn; Myocardium; Pregnancy; Rats

Topics: Animals; Animals, Newborn; Asphyxia Neonatorum; Blood Glucose; Body Water; Brain; Brain Edema; Dexamethasone; Disease Models, Animal; Glucose; Glycogen; Humans; Infant, Newborn; Potassium; Rats; Sodium; Water-Electrolyte Balance

Topics: Adaptation, Physiological; Adult; Altitude; Animals; Bolivia; Disease Models, Animal; Glucose; Glycogen; Heart Diseases; Hexosephosphates; Humans; Hypoxia; Lactates; Oxygen Consumption; Peru; Pyruvates; Rats

Topics: Animals; Brain; Disease Models, Animal; Glycogen; Haplorhini; Histocytochemistry; Kidney; Lipids; Liver; Malaria; Monkey Diseases; Organ Size; Plasmodium falciparum; Spleen; Staining and Labeling

Topics: Aging; Animals; Autopsy; Cartilage, Articular; Collagen; Decalcification Technique; Disease Models, Animal; Female; Femur Head; Glycogen; Hindlimb; Hypopituitarism; Joints; Male; Mice; Mice, Inbred Strains; Microscopy, Electron; Organoids; Osteoarthritis; Sex Factors; Staining and Labeling

Topics: Animals; Aortic Valve Stenosis; Capillaries; Cardiomegaly; Cats; Cineangiography; Collagen; Coronary Vessels; Disease Models, Animal; Dogs; Electrocardiography; Glycogen; Heart Conduction System; Heart Failure; Histological Techniques; Microscopy, Electron; Myocardium; Myofibrils; Organ Size; Organoids; Pulmonary Valve Stenosis; Rabbits

Topics: Adenine Nucleotides; Animals; Cardiomegaly; Collagen; Disease Models, Animal; DNA; Glycogen; Heart Failure; Mitochondria, Muscle; Muscle Proteins; Myocardium; Myofibrils; Organ Size; Rabbits; RNA; Sarcoplasmic Reticulum; Time Factors

Topics: Adenosine Triphosphate; Animals; Argon; Cochlea; Cochlear Nerve; Disease Models, Animal; Ear, Inner; Electrophysiology; Freeze Drying; Glucose; Glycogen; Guinea Pigs; Ischemia; Labyrinth Diseases; Labyrinthine Fluids; Lactates; Organ of Corti; Phosphocreatine; Time Factors; Vestibule, Labyrinth

Topics: Animals; Blood Glucose; Cell Nucleus; Cricetinae; Cytoplasm; Diabetes Mellitus; Disease Models, Animal; Endoplasmic Reticulum; Glycogen; Golgi Apparatus; Hyperglycemia; Insulin; Insulin Secretion; Islets of Langerhans; Microscopy, Electron; Mitochondria

Topics: Animals; Biopsy; Carbohydrate Metabolism, Inborn Errors; Chemical and Drug Induced Liver Injury; Disease Models, Animal; Endoplasmic Reticulum; Fructose; Galactose; Glucose; Glycogen; Golgi Apparatus; Humans; Liver; Liver Diseases; Male; Mannitol; Mannose; Microscopy; Microscopy, Electron; Rats; Rats, Inbred Strains; Ribosomes

Topics: Acetates; Alcohol Oxidoreductases; Anaerobiosis; Animals; Carbon Isotopes; Cell Count; Culture Media; Disease Models, Animal; Fatty Acids; Glucose; Glycogen; Lactates; Riboflavin Deficiency; Tetrahymena pyriformis; Time Factors

Topics: Animals; Coronary Vessels; Disease Models, Animal; Glycogen; Heart; Heart Ventricles; Ligation; Microscopy, Electron; Myocardial Infarction; Myocardium; Potassium; Rats; RNA

Topics: Anaerobiosis; Animals; Arrhythmias, Cardiac; Blood Glucose; Disease Models, Animal; Dogs; Fatty Acids, Nonesterified; Glucose; Glycogen; Glycolysis; Humans; Hypoxia; Insulin; Lactates; Myocardial Infarction; Myocardium; Rats

Ultrastructural and biochemical alterations were studied in the brainstem reticular formation of animals in which transient coma had been induced by controlled blows to the head. After a period of 7-10 days, animals that did not show obvious injury were artificially respired and sacrificed by perfusion with buffered formalin and glutaraldehyde. Histochemistry and light microscopy revealed chromatolysis of 10-15% of the neurons of pertinent segments of the nucleus giganto cellularis. There was much PAS-positive, diastase-sensitive material in the associated neuropil. Electron miscroscopy of the region confirmed the polysaccharide accumulation in dendrites, presynaptic boutons and preterminal axons. Similar material was found in some astrocytes. A longitudinal microchemical investigation with suitable controls of glycogen concentration in the brainstem demonstrated peak values at 5-7 days after concussion. No significant change in phosphorylase activity was demonstrated. The significance of glycogen accumulation in postconcussive injury and possible mechanisms for its accumulation in relation to changes in electrolyte balance and alterations in Kreb's cycle intermediates are discussed.

Topics: Animals; Axons; Brain Concussion; Brain Stem; Dendrites; Disease Models, Animal; Electroencephalography; Female; Glucosyltransferases; Glycogen; Guinea Pigs; Microscopy, Electron; Polysaccharides; Reticular Formation; Time Factors; Unconsciousness

Topics: Amino Acids; Animals; Animals, Newborn; Blood Glucose; Disease Models, Animal; Fasting; Fatty Acids, Nonesterified; Female; Gluconeogenesis; Glycogen; Glycolysis; Growth Hormone; Humans; Hypoglycemia; Infant, Newborn; Infant, Newborn, Diseases; Insulin; Ketones; Lipid Metabolism; Liver; Liver Glycogen; Pregnancy; Pregnancy in Diabetics; Rats; Swine

Topics: Adenosine Triphosphate; Animals; Cardiomegaly; Disease Models, Animal; Glycogen; Glycolysis; Heart; Heart Failure; Heart Rate; Hypoxia; In Vitro Techniques; Lactates; Male; Methods; Mitochondria, Muscle; Myocardium; Phosphorylases; Rats; Time Factors

Topics: Adenosine Triphosphate; Animals; Brain Neoplasms; Disease Models, Animal; Fluorometry; Freezing; Glioblastoma; Glucose; Glycogen; Histocytochemistry; Lactates; Mice; NAD; NADP; Neoplasm Transplantation; Neoplasms, Experimental; Neuroglia; Oxygen Consumption; Pentoses; Phosphates; Phosphocreatine; Transplantation, Homologous

Topics: Acid Phosphatase; Animals; Brain; Cerebral Cortex; Cerebrovascular Disorders; Disease Models, Animal; Glucuronidase; Glycogen; Hemiplegia; Hydrolases; Hypoxia; Hypoxia, Brain; Ischemic Attack, Transient; Lysosomes; Male; Mitochondria; Rats

Topics: Animals; Dihydrolipoamide Dehydrogenase; Disease Models, Animal; DNA; Glucosephosphate Dehydrogenase; Glycogen; Heart; Histocytochemistry; Inosine; L-Lactate Dehydrogenase; Male; Methods; Microscopy, Electron; Myocardial Infarction; Myocardium; Nucleosides; Rabbits; RNA; Succinate Dehydrogenase; Time Factors

Topics: Animals; Animals, Newborn; Antibiotics, Antineoplastic; Blood Glucose; Diabetes Mellitus; Disease Models, Animal; Fatty Acids, Nonesterified; Glucose Tolerance Test; Glycogen; Insulin; Ketone Bodies; Sheep; Triglycerides

Topics: Altitude; Animals; Blood Glucose; Blood Urea Nitrogen; Body Weight; Diaphragm; Disease Models, Animal; Glycogen; Hypoxia; Insulin; Lactates; Liver; Liver Glycogen; Male; Myocardium; Organ Size; Phenformin; Pyruvates; Rats

Topics: Animals; Blood Glucose; Carbamates; Carbohydrate Metabolism; Diabetes Mellitus; Diabetes Mellitus, Experimental; Disease Models, Animal; Fasting; Glucosamine; Glycogen; Glycosuria; Guinea Pigs; Hyperglycemia; Hypoglycemia; Lactates; Liver Glycogen; Male; Mice; Nitroso Compounds; Obesity; Oxazoles; Phenformin; Pyridinium Compounds; Rats

Topics: Age Factors; Animals; Cardiomegaly; Cardiomyopathies; Cell Nucleus; Cricetinae; Cytoplasmic Granules; Disease Models, Animal; Endoplasmic Reticulum; Female; Glycogen; Golgi Apparatus; Male; Microscopy, Electron; Mitochondria; Mitosis; Ribosomes; Sarcolemma

Topics: Acidosis; Adenosine Triphosphatases; Adenosine Triphosphate; Amino Acids; Animals; Blood Glucose; Blood Pressure; Blood Proteins; Blood Transfusion; Blood Volume; Disease Models, Animal; Dogs; Fructose; Glycogen; Hydrogen-Ion Concentration; Hyperbaric Oxygenation; Hypotension; Lactates; Methods; Phosphates; Phosphocreatine; Pulse; Pyruvates; Respiration

Topics: Acidosis; Animals; Blood Glucose; Cell Nucleus; Cricetinae; Cytoplasmic Granules; Diabetes Mellitus; Disease Models, Animal; Endoplasmic Reticulum; Glucagon; Glycogen; Golgi Apparatus; Insulin; Islets of Langerhans; Lysosomes; Male; Microscopy, Electron

Topics: Animals; Cardiomyopathies; Disease Models, Animal; Epinephrine; Glycogen; Glycogen Storage Disease; Glycoside Hydrolases; Heart; Myocardium; Rats

Topics: Adipose Tissue, Brown; Animals; Body Weight; Brain Chemistry; Chorionic Gonadotropin; Disease Models, Animal; Female; Fetus; Glycogen; Hydrogen-Ion Concentration; Hypoxia; Lactates; Lipids; Liver Glycogen; Myocardium; Organ Size; Placenta; Placenta Diseases; Pregnancy; Pregnancy, Prolonged; Rabbits

Topics: Animals; Coronary Vessels; Disease Models, Animal; Electrocoagulation; Glycogen; Male; Myocardial Infarction; Rats; Time Factors

Topics: Animals; Calcinosis; Cardiomyopathies; Disease Models, Animal; Endoplasmic Reticulum; Female; Glycogen; Histocytochemistry; L-Lactate Dehydrogenase; Microscopy, Electron; Mitochondria; Myocardium; Myofibrils; Necrosis; Nephrectomy; Parathyroid Glands; Rats; Succinate Dehydrogenase; Transferases; Uremia

Topics: Animals; Basement Membrane; Blood Glucose; Diabetes Mellitus; Diabetic Nephropathies; Disease Models, Animal; Glycogen; Golgi Apparatus; Lysosomes; Mice; Microscopy, Electron

Topics: Animals; Dihydrolipoamide Dehydrogenase; Disease Models, Animal; Dogs; Glucosephosphate Dehydrogenase; Glutamate Dehydrogenase; Glycogen; Heart; Histocytochemistry; L-Lactate Dehydrogenase; Lipid Metabolism; Methods; Myocardial Infarction; Myocardium; Proteins; RNA; Succinate Dehydrogenase; Thiamine Pyrophosphate

Topics: Adenosine Triphosphate; Anesthesia; Animals; Centrifugation; Cerebral Cortex; Disease Models, Animal; Fluorometry; Glucose; Glycogen; Ischemic Attack, Transient; Lipid Metabolism; Male; Mice; Phosphates; Phosphocreatine

Topics: Acetylcholinesterase; Adenosine Triphosphate; Amino Acids; Aminobutyrates; Animals; Brain; Chromatography, Paper; Disease Models, Animal; Glucose; Glycogen; Lactates; Oxygen Consumption; Phosphates; Phosphocreatine; Plant Extracts; Propionates; Rats; Seizures; Toxins, Biological

Topics: Adaptation, Physiological; Altitude; Animals; Aortic Coarctation; Cerebral Cortex; Disease Models, Animal; Glycogen; Heart; Heart Failure; Hypoxia; Methods; Muscle Contraction; Myocardium; Phosphocreatine; Protein Biosynthesis; Rats; RNA

Topics: Alkaline Phosphatase; Animals; Azo Compounds; Disease Models, Animal; Glycogen; Histocytochemistry; Humans; Indicators and Reagents; Leukemia; Leukemoid Reaction; Leukocyte Count; Leukocytes; Leukocytosis; Lipids; Rabbits; Staphylococcal Infections

Topics: Animals; Cytoplasm; Disease Models, Animal; Glycogen; Hypoxia; Lipids; Liver; Liver Glycogen; Lysosomes; Microscopy, Electron; Rats