c-peptide and Disease-Models--Animal

Type 1 diabetes is associated with such complications as blindness, kidney failure, and nerve damage. Replacing C-peptide, a hormone normally co-secreted with insulin, has been shown to reduce diabetes-related complications. Interestingly, after nearly 30 years of positive research results, C-peptide is still not being co-administered with insulin to diabetic patients. The following review discusses the potential of C-peptide as an auxilliary replacement therapy and why it's not currently being used as a therapeutic.

Topics: Animals; Bibliometrics; C-Peptide; Clinical Trials as Topic; Diabetes Complications; Diabetes Mellitus, Type 1; Disease Models, Animal; History, 20th Century; History, 21st Century; Humans; Insulin; Insulin-Secreting Cells; Iron; Protein Binding; Serum Albumin; Zinc

In this review, we present findings that support autocrine cell protection by C-peptide in the context of clinical studies of type 1 diabetes (T1D), which universally measure C-peptide serum levels as a surrogate for β cell functional mass. Over the last decade, evidence has accumulated that supports models in which C-peptide, cosecreted with insulin by pancreatic β cells, acts on peripheral targets including the vascular endothelium to reduce oxidative stress and apoptosis subsequent to exposure to diabetic insults. In parallel, as assays have become more sensitive, C-peptide has been detected in the circulation of most subjects with T1D where higher C-peptide levels are associated with fewer and slower development of diabetic microvascular complications, consistent with antioxidant protection by C-peptide. Clinical trials investigating C-peptide-replacement therapy effects have demonstrated amelioration of T1D nephropathy and neuropathy. Recently, the antioxidant action of C-peptide was extended to the β cells secreting it, that is an autocrine mechanism. Autocrine protection has major implications for the treatment of diabetes because the more C-peptide secreted, the more protection provided to the same β cells resulting in a slower decay in β cell functional mass over the time course of disease. Why β cells evolved to cosecrete an antioxidant C-peptide hormone together with the glycaemia-lowering insulin hormone is explored in the context of proposed evolutionary advantages of physiologically transient oxidative stress and insulin resistance as an adaptation for survival through times of fuel scarcity. The importance of recognizing autocrine C-peptide protection of functional β cell mass in observational clinical studies, and its therapeutic implications in interventional C-peptide-replacement studies, will be discussed.

Topics: Animals; C-Peptide; Diabetes Mellitus, Type 1; Disease Models, Animal; Endothelial Cells; Humans; Insulin Resistance; Insulin-Secreting Cells; Reactive Oxygen Species

Kidney disease is a serious development in diabetes mellitus and poses an increasing clinical problem. Despite increasing incidence and prevalence of diabetic kidney disease, there have been no new therapies for this condition in the last 20 years. Mounting evidence supports a biological role for C-peptide, and findings from multiple studies now suggest that C-peptide may beneficially affect the disturbed metabolic and pathophysiological pathways leading to the development of diabetic nephropathy. Studies of C-peptide in animal models and in humans with type 1 diabetes all suggest a renoprotective effect for this peptide. In diabetic rodents, C-peptide reduces glomerular hyperfiltration and albuminuria. Cohort studies of diabetic patients with combined islet and kidney transplants suggest that maintained C-peptide secretion is protective of renal graft function. Further, in short-term studies of patients with type 1 diabetes, administration of C-peptide is also associated with a lowered hyperfiltration rate and reduced microalbuminuria. Thus, the available information suggests that type 1 diabetes should be regarded as a dual hormone deficiency disease and that clinical trials of C-peptide in diabetic nephropathy are both justified and urgently required.

Topics: Animals; C-Peptide; Diabetes Mellitus, Type 1; Diabetic Nephropathies; Disease Models, Animal; Humans

Recent research in nutritional control of aging suggests that cytosolic increases in the reduced form of nicotinamide adenine dinucleotide and decreasing nicotinamide adenine dinucleotide metabolism plays a central role in controlling the longevity gene products sirtuin 1 (SIRT1), adenosine monophosphate-activated protein kinase (AMPK) and forkhead box O3 (FOXO3). High nutrition conditions, such as the diabetic milieu, increase the ratio of reduced to oxidized forms of cytosolic nicotinamide adenine dinucleotide through cascades including the polyol pathway. This redox change is associated with insulin resistance and the development of diabetic complications, and might be counteracted by insulin C-peptide. My research and others' suggest that the SIRT1-liver kinase B1-AMPK cascade creates positive feedback through nicotinamide adenine dinucleotide synthesis to help cells cope with metabolic stress. SIRT1 and AMPK can upregulate liver kinase B1 and FOXO3, key factors that help residential stem cells cope with oxidative stress. FOXO3 directly changes epigenetics around transcription start sites, maintaining the health of stem cells. 'Diabetic memory' is likely a result of epigenetic changes caused by high nutritional conditions, which disturb the quiescent state of residential stem cells and impair tissue repair. This could be prevented by restoring SIRT1-AMPK positive feedback through activating FOXO3.

Topics: Aging; AMP-Activated Protein Kinases; Animals; C-Peptide; Diabetes Complications; Diabetic Angiopathies; Disease Models, Animal; Epigenesis, Genetic; Feedback, Physiological; Forkhead Box Protein O3; Humans; Hypoxia; Insulin Resistance; NAD; Oxidation-Reduction; Oxidative Stress; Signal Transduction; Sirtuin 1

The incidence and prevalence of diabetes are increasing worldwide. According to the International Diabetes Federation, more than 55 million people in the European region have diabetes, and this number is expected to rise to 64 million in 2030, with most of the cases being due to type 2 diabetes. Diabetes is associated with potentially serious microvascular and macrovascular complications such as nephropathy, neuropathy, and retinopathy as well as coronary artery disease. The pathophysiological mechanism behind this phenomenon is complex. In recent years the impact of proinsulin C-peptide in the development of vascular disease has been highlighted, but it displays differential function in type 1 and type 2 diabetes. In type 1 diabetes, which is characterized by a lack of insulin and C-peptide, supplementation of C-peptide has been shown to improve microvascular complications. In type 2 diabetes, however, C-peptide levels are increased above normal levels and correlate with the occurrence of macrovascular complications and cardiovascular deaths. This review focuses on the impact of C-peptide in the atherogenic process.

Topics: Animals; Atherosclerosis; C-Peptide; Diabetic Angiopathies; Disease Models, Animal; Endothelium, Vascular; Humans; Hyperglycemia; Inflammation; NF-kappa B

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

Topics: Animals; C-Peptide; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Disease Models, Animal; Humans; Neural Conduction; Nitric Oxide Synthase; Randomized Controlled Trials as Topic; Sodium-Potassium-Exchanging ATPase

Ecballium elaterium (EE), widely used plant in Mediterranean medicine, showed anticancer activity. This study aimed to investigate EE effects on liver fibrosis in an animal model of thioacetamide (TAA). Intraperitoneal administration of TAA was performed twice weekly for four weeks in C57BL6J mice. Livers were extracted and serum were evaluated for inflammatory markers (H&E staining, ALT, AST, ALP), pro-inflammatory cytokines, fibrosis (Sirius red staining, Masson's trichrome, α-smooth muscle actin and collagen III), and metabolic (cholesterol, triglyceride, C-peptide, and fasting-blood-sugar) profiles. Glutathione, glutathione peroxidase, and catalase liver antioxidant markers were assessed. Tissue-resident NK cells from mice livers were functionally assessed for activating receptors and cytotoxicity. Compared to vehicle-treated mice, the TAA-induced liver injury showed attenuation in the histopathology outcome following EE treatment. In addition, EE-treated mice resulted in decreased serum levels of ALT, AST, and ALP, associated with a decrease in IL-20, TGF-β, IL-17, IL-22 and MCP-1 concentrations. Moreover, EE-treated mice exhibited improved lipid profile of cholesterol, triglycerides, C-peptide, and FBS. EE treatment maintained GSH, GPX, and CAT liver antioxidant activity and led to elevated counts of tissue-resident NK (trNK) cells in the TAA-mice. Consequently, trNK demonstrated an increase in CD107a and IFN-γ with improved potentials to kill activated hepatic-stellate cells in an in vitro assay. EE exhibited antifibrotic and antioxidative effects, increased the number of trNK cells, and improved metabolic outcomes. This plant extract could be a targeted therapy for patients with advanced liver injury.

Topics: Animals; Antioxidants; C-Peptide; Disease Models, Animal; Glutathione; Humans; Killer Cells, Natural; Liver; Liver Cirrhosis; Mice; Oxidative Stress; Thioacetamide

MOTS-c, a mitochondrial-derived peptide (MDP), has been shown to have multiple biological activities such as antioxidation, anti-inflammation, and anti-apoptosis properties. In the present study, we aimed at evaluating the therapeutic effect of MOTS-c peptide in an animal model of heart failure. The heart failure mouse model was made by transverse aortic constriction (TAC) operations. The MOTS-c peptide was administrated subcutaneously by using an osmotic pump. At the end of the animal experiment, cardiac function was evaluated by echocardiography, and heart tissues were subjected to histological and molecular analysis. In vitro cultured H9C2 cells were used to test the effects of MOTS-c overexpression on cell death in response to H

Topics: AMP-Activated Protein Kinases; Animals; Antioxidants; C-Peptide; Disease Models, Animal; Heart; Heart Failure; Mice; Mice, Inbred C57BL; Peptides

Melatonin (Mel) and its receptors are promising for glycaemic control in patients with type 2 diabetes mellitus (T2DM) and its complications, but there is significant heterogeneity among studies. This study aims to investigate the effects of Mel receptor agonist Neu-P11 on glucose metabolism, immunity, and islet function in T2DM rats.. In this study, SD rats were treated with a high-fat diet and streptozotocin (STZ) to establish a T2DM model. The glucose oxidase method was used to measure blood glucose levels. Glucose and insulin tolerance tests were used to assess glucose metabolism. Haematoxylin-eosin staining was used to observe pancreatic tissue injury. The apoptosis of isletβ cells was analysed by TUNEL and insulin staining. Reactive oxygen species (ROS) levels and immune cell expression were analysed by flow cytometry. IF was used to analyse the activation of microglia. The immunoglobulins: IgA, IgG, IgM, tumour necrosis factorα (TNF-α), interleukins IL-10 and IL-1β, interferonγ (IFN-γ), C-peptide, and insulin levels were determined by ELISA. The expression of CD11b, CD86, cleaved caspase 3, p21, and P16 proteins were analysed by western blot.. The results showed that the blood glucose level increased, insulin resistance occurred, spleen coefficient and ROS levels increased, humoral immunity in peripheral blood decreased, and inflammation increased in the model group compared to the control group. After Mel and Neu-P11 treatment, the blood glucose level decreased significantly, insulin sensitivity improved, spleen coefficient and ROS levels decreased, humoral immunity in peripheral blood was enhanced, and inflammation improved in T2DM rats. Brain functional analysis of T2DM rats showed that microglia cells were activated, TNF-α and IL-β levels were increased, and IL-10 levels were decreased. Mel and Neu-P11 treatment reversed these indexes. Functional analysis of islets in T2DM rats showed that islet structure inflammation was impaired, isletβ cells were apoptotic, p21 and p16 protein expressions were increased, and blood C-peptide and insulin were decreased. Mel and Neu-P11 treatment restored the function of pancreatic b cells and improved the damage of pancreatic tissue.. Melatonin and its receptor Neu-P11 can reduce the blood glucose level, enhance humoral and cellular immunity, inhibit microglia activation and inflammation, and repair isletβ cell function, and this improve the characterization of T2DM-related diseases.

Topics: Animals; Blood Glucose; C-Peptide; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Diet, High-Fat; Disease Models, Animal; Glycemic Control; Indoles; Insulin Resistance; Melatonin; Pyrans; Rats; Rats, Sprague-Dawley; Receptors, Melatonin; Streptozocin

Wolfram syndrome (WS), also known as a DIDMOAD (diabetes insipidus, early-onset diabetes mellitus, optic nerve atrophy and deafness) is a rare autosomal disorder caused by mutations in the Wolframin1 (

Topics: Animals; C-Peptide; Diabetes Mellitus, Experimental; Disease Models, Animal; Glucagon-Like Peptide-1 Receptor; Hearing Loss, Sensorineural; Liraglutide; Male; Nerve Degeneration; Optic Nerve; Phenotype; Rats; Visual Pathways; Wolfram Syndrome

The main objective of this experimental study was to evaluate the feasibility of diabetes induction by total pancreatectomy and pancreatic allotransplant after diabetes induction by total pancreatectomy. The secondary objective was to evaluate metabolic (C-peptide, glycemia) and inflammatory (lactate and platelet levels) parameters after diabetes induction by total pancreatectomy and pancreatic allotransplant after total pancreatectomy.. The study protocol was approved by the French Minister of Research (APAFiS no.18169). Insulin-dependent diabetes was induced by total pancreatectomy in one male Sus scrofa pig, and pancreatic allotransplant was performed, after total pancreatectomy, in 3 male Sus scrofa pigs. Total pancreatectomy was performed under general anesthesia,with meticulous dissection of the portal vein and the splenic vein to preserve the spleen. Concerning pancreas procurement, extensive pancreas preparation occurred during thewarm phase,before coldperfusion. Pancreatic allotransplant was performed using donor aorta (with superior mesenteric artery and celiac trunk).. Diabetes induction was successful, with negative C-peptide values at 3 hours after total pancreatectomy. Glycemic control without hypoglycemic events was obtained with the use of long-acting insulin administered once per day. No rapid-acting insulin was used. In animals that received pancreatic allotransplant, after enteral feeding was started, glycemic control without hypoglycemic events and without insulin was obtained in 2 animals.. In an experimental porcine model, diabetes induction by total pancreatectomy and pancreatic allotransplant after total pancreatectomy are feasible and effective. The development of these models offers the potential for new investigations into ischemia-reperfusion injuries, improvement of pancreas procurement methods, and preservation techniques.

Topics: Animals; Biomarkers; Blood Glucose; Blood Platelets; C-Peptide; Diabetes Mellitus, Type 1; Disease Models, Animal; Feasibility Studies; Hypoglycemic Agents; Insulin Glargine; Lactic Acid; Male; Pancreas Transplantation; Pancreatectomy; Sus scrofa; Time Factors; Transplantation, Homologous

Clinical trials and animal studies have shown that sodium-glucose co-transporter type 2 (SGLT2) inhibitors improve pancreatic beta cell function. Our study aimed to investigate the effect of dapagliflozin on islet morphology and cell phenotype, and explore the origin and possible reason of the regenerated beta cells.. Two diabetic mouse models, db/db mice and pancreatic alpha cell lineage-tracing (glucagon-β-gal) mice whose diabetes was induced by high fat diet combined with streptozotocin, were used. Mice were treated by daily intragastric administration of dapagliflozin (1 mg/kg) or vehicle for 6 weeks. The plasma insulin, glucagon and glucagon-like peptide-1 (GLP-1) were determined by using ELISA. The evaluation of islet morphology and cell phenotype was performed with immunofluorescence. Primary rodent islets and αTC1.9, a mouse alpha cell line, were incubated with dapagliflozin (0.25-25 μmol/L) or vehicle in the presence or absence of GLP-1 receptor antagonist for 24 h in regular or high glucose medium. The expression of specific markers and hormone levels were determined.. Treatment with dapagliflozin significantly decreased blood glucose in the two diabetic models and upregulated plasma insulin and GLP-1 levels in db/db mice. The dapagliflozin treatment increased islet and beta cell numbers in the two diabetic mice. The beta cell proliferation as indicated by C-peptide and BrdU double-positive cells was boosted by dapagliflozin. The alpha to beta cell conversion, as evaluated by glucagon and insulin double-positive cells and confirmed by using alpha cell lineage-tracing, was facilitated by dapagliflozin. After the dapagliflozin treatment, some insulin-positive cells were located in the duct compartment or even co-localized with duct cell markers, suggestive of duct-derived beta cell neogenesis. In cultured primary rodent islets and αTC1.9 cells, dapagliflozin upregulated the expression of pancreatic endocrine progenitor and beta cell specific markers (including Pdx1) under high glucose condition. Moreover, dapagliflozin upregulated the expression of Pcsk1 (which encodes prohormone convertase 1/3, an important enzyme for processing proglucagon to GLP-1), and increased GLP-1 content and secretion in αTC1.9 cells. Importantly, the dapagliflozin-induced upregulation of Pdx1 expression was attenuated by GLP-1 receptor antagonist.. Except for glucose-lowering effect, dapagliflozin has extra protective effects on beta cells in type 2 diabetes. Dapagliflozin enhances beta cell self-replication, induces alpha to beta cell conversion, and promotes duct-derived beta cell neogenesis. The promoting effects of dapagliflozin on beta cell regeneration may be partially mediated via GLP-1 secreted from alpha cells.

Topics: Animals; Benzhydryl Compounds; Blood Glucose; C-Peptide; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Disease Models, Animal; Endocrine Cells; Glucagon; Glucagon-Like Peptide 1; Glucagon-Like Peptide-1 Receptor; Glucagon-Secreting Cells; Glucose; Glucosides; Insulin; Insulin-Secreting Cells; Male; Mice; Proprotein Convertase 1; Regeneration; Sodium-Glucose Transporter 2 Inhibitors

Islet transplantation has been proved to be effective in delaying early stage of DN. This study was established to observe the mechanism of islet transplantation on early diabetic nephropathy (DN).. The diabetes mellitus (DM) rat model was established by an injection of a single-dose streptozotocin. According to the treatment, the rats were randomly divided into 4 groups: the untreated DN rats (DN group); the C-peptide treated rats (CP group); the islet transplanted rats (IT group); the normal control rats (NC group). Renal function and structure of glomerular filtration barrier (GFB) were evaluated by urinalysis and histopathological examination, respectively. The renal fibrotic factors, TGF- β1 and CTGF, as well as the anti-renal fibrosis factor HGF were assessed by immunohistochemical staining and western blotting methods.. After C-peptide treatment and islet transplantation, the GFB structure was obviously improved. The blood glucose significantly decreased in the IT group. The 24h urine protein and glomerular basement membrane thickness decreased, the pathological changes of podocytes improved, TGF- β1 and CTGF decreased and HGF increased in the CP group and the IT group compared with that in the DN group (P < 0.05), especially in the IT group.. Islet transplantation could ameliorate the structure of GFB of early DN in a rat model, and the treatment effect was partly attributed to the restoration of C-peptide concentration. Suppressing the fibrosis system can be the potential mechanism of islet transplantation, which is independent of blood glucose control.

Topics: Animals; C-Peptide; Diabetes Mellitus; Diabetic Nephropathies; Disease Models, Animal; Fibrosis; Glomerular Filtration Barrier; Humans; Islets of Langerhans Transplantation; Male; Rats; Rats, Sprague-Dawley; Streptozocin; Transforming Growth Factor beta1; Urinalysis

Type 2 diabetes mellitus and hypertension are two major risk factors leading to heart failure and cardiovascular damage. Lowering blood sugar by the sodium-glucose co-transporter 2 inhibitor empagliflozin provides cardiac protection. We established a new rat model that develops both inducible diabetes and genetic hypertension and investigated the effect of empagliflozin treatment to test the hypothesis if empagliflozin will be protective in a heart failure model which is not based on a primary vascular event. The transgenic Tet29 rat model for inducible diabetes was crossed with the mRen27 hypertensive rat to create a novel model for heart failure with two stressors. The diabetic, hypertensive heart failure rat (mRen27/tetO-shIR) were treated with empagliflozin (10 mg/kg/d) or vehicle for 4 weeks. Cardiovascular alterations were monitored by advanced speckle tracking echocardiography, gene expression analysis and immunohistological staining. The novel model with increased blood pressure und higher blood sugar levels had a reduced survival compared to controls. The rats develop heart failure with reduced ejection fraction. Empagliflozin lowered blood sugar levels compared to vehicle treated animals (182.3 ± 10.4 mg/dl vs. 359.4 ± 35.8 mg/dl) but not blood pressure (135.7 ± 10.3 mmHg vs. 128.2 ± 3.8 mmHg). The cardiac function was improved in all three global strains (global longitudinal strain - 8.5 ± 0.5% vs. - 5.5 ± 0.6%, global radial strain 20.4 ± 2.7% vs. 8.8 ± 1.1%, global circumferential strain - 11.0 ± 0.7% vs. - 7.6 ± 0.8%) and by increased ejection fraction (42.8 ± 4.0% vs. 28.2 ± 3.0%). In addition, infiltration of macrophages was decreased by treatment (22.4 ± 1.7 vs. 32.3 ± 2.3 per field of view), despite mortality was not improved. Empagliflozin showed beneficial effects on cardiovascular dysfunction. In this novel rat model of combined hypertension and diabetes, the improvement in systolic and diastolic function was not secondary to a reduction in left ventricular mass or through modulation of the afterload, since blood pressure was not changed. The mRen27/tetO-shIR strain should provide utility in separating blood sugar from blood pressure-related treatment effects.

Topics: Animals; Benzhydryl Compounds; C-Peptide; Cardiotonic Agents; Diabetes Mellitus, Type 2; Disease Models, Animal; Glucosides; Heart Failure; Humans; Hyperinsulinism; Hypertension; Male; Rats; Rats, Sprague-Dawley; Rats, Transgenic; Sodium-Glucose Transporter 2 Inhibitors

The fructooligosaccharide 1-kestose cannot be hydrolyzed by gastrointestinal enzymes, and is instead fermented by the gut microbiota. Previous studies suggest that 1-kestose promotes increases in butyrate concentrations in vitro and in the ceca of rats. Low levels of butyrate-producing microbiota are frequently observed in the gut of patients and experimental animals with type 2 diabetes (T2D). However, little is known about the role of 1-kestose in increasing the butyrate-producing microbiota and improving the metabolic conditions in type 2 diabetic animals. Here, we demonstrate that supplementation with 1-kestose suppressed the development of diabetes in Otsuka Long-Evans Tokushima Fatty (OLETF) rats, possibly through improved glucose tolerance. We showed that the cecal contents of rats fed 1-kestose were high in butyrate and harbored a higher proportion of the butyrate-producing genus Anaerostipes compared to rats fed a control diet. These findings illustrate how 1-kestose modifications to the gut microbiota impact glucose metabolism of T2D, and provide a potential preventative strategy to control glucose metabolism associated with dysregulated insulin secretion.

Topics: Animals; Blood Glucose; Body Weight; C-Peptide; Cecum; Diabetes Mellitus, Type 2; Disease Models, Animal; Disease Progression; Drinking; Fasting; Gastrointestinal Microbiome; Glucose; Insulin; Organ Size; Rats; Trisaccharides

Cardiovascular and renal complications are the predominant causes of morbidity and mortality amongst patients with diabetes. Development of novel treatments have been hampered by the lack of available animal models recapitulating the human disease. We hypothesized that experimental diabetes in rats combined with a cardiac or renal stressor, would mimic diabetic cardiomyopathy and nephropathy, respectively. Diabetes was surgically induced in male Sprague Dawley rats by 90% pancreatectomy (Px). Isoprenaline (Iso, 1 mg/kg, sc., 10 days) was administered 5 weeks after Px with the aim of inducing cardiomyopathy, and cardiac function and remodeling was assessed by echocardiography 10 weeks after surgery. Left ventricular (LV) fibrosis was quantified by Picro Sirius Red and gene expression analysis. Nephropathy was induced by Px combined with uninephrectomy (Px-UNx). Kidney function was assessed by measurement of glomerular filtration rate (GFR) and urine albumin excretion, and kidney injury was evaluated by histopathology and gene expression analysis. Px resulted in stable hyperglycemia, hypoinsulinemia, decreased C-peptide, and increased glycated hemoglobin (HbA1c) compared with sham-operated controls. Moreover, Px increased heart and LV weights and dimensions and caused a shift from α-myosin heavy chain (MHC) to β-MHC gene expression. Isoprenaline treatment, but not Px, decreased ejection fraction and induced LV fibrosis. There was no apparent interaction between Px and Iso treatment. The superimposition of Px and UNx increased GFR, indicating hyperfiltration. Compared with sham-operated controls, Px-UNx induced albuminuria and increased urine markers of kidney injury, including neutrophil gelatinase-associated lipocalin (NGAL) and podocalyxin, concomitant with upregulated renal gene expression of NGAL and kidney injury molecule 1 (KIM-1). Whereas Px and isoprenaline separately produced clinical endpoints related to diabetic cardiomyopathy, the combination of the two did not accentuate disease development. Conversely, Px in combination with UNx resulted in several clinical hallmarks of diabetic nephropathy indicative of early disease development.

Topics: Albuminuria; Animals; C-Peptide; Diabetes Mellitus, Experimental; Diabetic Cardiomyopathies; Diabetic Nephropathies; Disease Models, Animal; Fibrosis; Glomerular Filtration Rate; Heart; Isoproterenol; Kidney; Lipocalin-2; Male; Pancreatectomy; Rats; Rats, Sprague-Dawley; Renal Insufficiency

The therapeutic potential of adipose-derived stem cell conditioned medium (ASC-CM) was studied in the rabbit model of critical limb ischemia (CLI).. Rabbits received treatment with ASC-CM or placebo. Gastrocnemius muscle tissue was collected 35 days after ischemia induction. Ischemic changes were evaluated in hematoxylin-eosin stained tissues for early (necrotic lesions/granulation tissue) and late (fibrous scars) phases of tissue repair. The expression of proangiogenic miR-126 was also evaluated using in situ hybridization. The levels of cytokines, insulin, and C-peptide were measured in blood.. Early repair phases were observed more often in placebo-treated samples (45.5%) than in ASC-CM-treated ones (22.2%). However, the difference was not statistically significant. We demonstrated a statistically significant positive correlation between the early healing phases in tissue samples and C-peptide levels in peripheral blood. The expression of proangiogenic miR-126 was also shown in a number of structures in all phases of ischemic tissue healing.. Based on our results, we believe that treatment with ASC-CM has the potential to accelerate the healing process in ischemic tissues in the rabbit model of CLI. The whole healing process was accompanied by miR-126 tissue expression. C-peptide could be used to monitor the course of the tissue healing process.

Topics: Adult; Animals; C-Peptide; Cicatrix; Culture Media, Conditioned; Cytokines; Diabetes Mellitus, Experimental; Diabetic Foot; Disease Models, Animal; Fibrosis; Granulation Tissue; Hindlimb; Humans; In Situ Hybridization; Insulin; Ischemia; Male; Mesenchymal Stem Cells; MicroRNAs; Muscle, Skeletal; Necrosis; Neovascularization, Physiologic; Rabbits; Wound Healing

Non-genetic factors are crucial in the pathogenesis of type 1 diabetes (T1D), a disease caused by autoimmunity against insulin-producing β-cells. Exposure to medications in the prenatal period may influence the immune system maturation, thus altering self-tolerance. Prenatal administration of betamethasone -a synthetic glucocorticoid given to women at risk of preterm delivery- may affect the development of T1D. It has been previously demonstrated that prenatal betamethasone administration protects offspring from T1D development in nonobese diabetic (NOD) mice. The direct effect of betamethasone on the immature and mature immune system of NOD mice and on target β-cells is analysed in this paper. In vitro, betamethasone decreased lymphocyte viability and induced maturation-resistant dendritic cells, which in turn impaired γδ T cell proliferation and decreased IL-17 production. Prenatal betamethasone exposure caused thymus hypotrophy in newborn mice as well as alterations in immune cells subsets. Furthermore, betamethasone decreased β-cell growth, reduced C-peptide secretion and altered the expression of genes related to autoimmunity, metabolism and islet mass in T1D target tissue. These results support the protection against T1D in the betamethasone-treated offspring and demonstrate that this drug alters the developing immune system and β-cells. Understanding how betamethasone generates self-tolerance could have potential clinical relevance in T1D.

Topics: Animals; Autoimmunity; Betamethasone; C-Peptide; Cell Survival; Diabetes Mellitus, Type 1; Disease Models, Animal; Female; Glucocorticoids; Humans; Immune Tolerance; Inclusion Bodies; Insulin-Secreting Cells; Lymphocyte Activation; Maternal Exposure; Mice; Mice, Inbred NOD; Obstetric Labor, Premature; Pregnancy

In type 1 diabetes, a renewable source of human pancreatic β cells, in particular from human induced pluripotent stem cell (hiPSC) origin, would greatly benefit cell therapy. Earlier work showed that pancreatic progenitors differentiated from human embryonic stem cells in vitro can further mature to become glucose responsive following macroencapsulation and transplantation in mice. Here we took a similar approach optimizing the generation of pancreatic progenitors from hiPSCs. This work demonstrates that hiPSCs differentiated to pancreatic endoderm in vitro can be efficiently and robustly generated under large-scale conditions. The hiPSC-derived pancreatic endoderm cells (HiPECs) can further differentiate into glucose-responsive islet-like cells following macroencapsulation and in vivo implantation. The HiPECs can protect mice from streptozotocin-induced hyperglycemia and maintain normal glucose homeostasis and equilibrated plasma glucose concentrations at levels similar to the human set point. These results further validate the potential use of hiPSC-derived islet cells for application in clinical settings.

Topics: Animals; Biomarkers; Blood Glucose; C-Peptide; Cell Differentiation; Diabetes Mellitus, Experimental; Disease Models, Animal; Endoderm; Fluorescent Antibody Technique; Humans; Hyperglycemia; Immunophenotyping; Induced Pluripotent Stem Cells; Insulin; Insulin-Secreting Cells; Mice; Models, Biological; Stem Cell Transplantation; Treatment Outcome

The bone marrow cavity (BMC) has recently been identified as an alternative site to the liver for islet transplantation. This study aimed to compare the BMC with the liver as an islet allotransplantation site in diabetic monkeys. Diabetes was induced in Rhesus monkeys using streptozocin, and the monkeys were then divided into the following three groups: Group1 (islets transplanted in the liver with immunosuppressant), Group 2 (islets transplanted in the tibial BMC), and Group 3 (islets transplanted in the tibial BMC with immunosuppressant). The C-peptide and blood glucose levels were preoperatively measured. An intravenous glucose tolerance test (IVGTT) was conducted to assess graft function, and complete blood cell counts were performed to assess cell population changes. Cytokine expression was measured using an enzyme-linked immune sorbent assay (ELISA) and MILLIPLEX. Five monkeys in Group 3 exhibited a significantly increased insulin-independent time compared with the other groups (Group 1: 78.2 ± 19.0 days; Group 2: 58.8 ± 17.0 days; Group 3: 189.6 ± 26.2 days) and demonstrated increases in plasma C-peptide 4 months after transplantation. The infusion procedure was not associated with adverse effects. Functional islets in the BMC were observed 225 days after transplantation using the dithizone (DTZ) and insulin/glucagon stains. Our results showed that allogeneic islets transplanted in the BMC of diabetic Rhesus monkeys remained alive and functional for a longer time than those transplanted in the liver. This study was the first successful demonstration of allogeneic islet engraftment in the BMC of non-human primates (NHPs).

Topics: Animals; Blood Glucose; Bone Marrow Transplantation; C-Peptide; Diabetes Mellitus, Experimental; Disease Models, Animal; Glucose Tolerance Test; Graft Survival; Humans; Immunosuppressive Agents; Islets of Langerhans; Islets of Langerhans Transplantation; Liver; Macaca mulatta; Tibia; Transplantation, Heterologous

The study aims to evaluate whether C-peptide can reduce gut injury during hemorrhagic shock (HS) and resuscitation (R) therefore attenuate shock-induced inflammation and subsequent acute lung injury.. Twelve-week-old male mice (C57/BL6) were hemorrhaged (mean arterial blood pressure maintained at 35 mm Hg for 60 minutes) and then resuscitated with Ringer's lactate, followed by red blood cell transfusion with (HS/R) or without C-peptide (HS/R + C-peptide). Mouse gut permeability, bacterial translocation into the circulatory system and intestinal pathology, circulating HMGB1, and acute lung injury were assessed at different times after R. The mice in the control group underwent sham procedures without HS.. Compared to the sham group, the mice in the HS/R group showed increased gut permeability (6.07 ± 3.41 μg of FD4/mL) and bacterial translocation into the circulatory system (10.05 ± 4.92, lipopolysaccharide [LPS] of pg/mL), and increased gut damage; conversely, mice in the HS/R + C-peptide group showed significantly reduced gut permeability (1.59 ± 1.39 μg of FD4/mL; p < 0.05) and bacterial translocation (4.53 ± 1.08 pg of LPS/mL; p < 0.05) with reduced intestine damage. In addition, mice in the HS/R group had increased circulating HMGB1 (21.64 ± 14.17 ng/mL), lung myeloperoxidase) activity (34.4 ± 8.91 mU/g of tissue), and pulmonary protein leakage (2.33 ± 1.16 μg Evans blue/g tissue per minute). Mice in the HS/R + C-peptide group showed decreased HMGB1 (7.27 ± 1.93 ng/mL; p < 0.05), lung myeloperoxidase (23.73 ± 8.39 mU/g of tissue; p < 0.05), and pulmonary protein leakage (1.17 ± 0.42 Evans Blue/g tissue per minute; p < 0.05).. Our results indicate that C-peptide exerts beneficial effects to attenuate gut injury and dysfunction, therefore diminishing lung inflammation and subsequent injury in mice with HS and R.

Topics: Acute Lung Injury; Animals; Bacterial Translocation; C-Peptide; Capillary Permeability; Disease Models, Animal; HMGB1 Protein; Ileum; Mice; Mice, Inbred C57BL; Resuscitation; Shock, Hemorrhagic

Insulin-producing cells (IPCs) derived from a patient's own stem cells offer great potential for autologous transplantation in diabetic patients. However, the limited survival of engrafted cells remains a bottleneck in the application of this strategy. The present study aimed to investigate whether nanoparticle-based magnetic resonance (MR) tracking can be used to detect the loss of grafted stem cell-derived IPCs in a sensitive and timely manner in a diabetic monkey model. Pancreatic progenitor cells (PPCs) were isolated from diabetic monkeys and labeled with superparamagnetic iron oxide nanoparticles (SPIONs). The SPION-labeled cells presented as hypointense signals on MR imaging (MRI). The labeling procedure did not affect the viability or IPC differentiation of PPCs. Importantly, the total area of the hypointense signal caused by SPION-labeled IPCs on liver MRI decreased before the decline in C-peptide levels after autotransplantation. Histological analysis revealed no detectable immune response to the grafts and many surviving insulin- and Prussian blue-positive cell clusters on liver sections at one year post-transplantation. Collectively, this study demonstrates that SPIO nanoparticles can be used to label stem cells for noninvasive, sensitive, longitudinal monitoring of stem cell-derived IPCs in large animal models using a conventional MR imager.

Topics: Animals; C-Peptide; Cell Differentiation; Cell Tracking; Contrast Media; Diabetes Mellitus, Type 1; Disease Models, Animal; Ferric Compounds; Humans; Macaca fascicularis; Magnetic Resonance Imaging; Magnetite Nanoparticles; Mesenchymal Stem Cell Transplantation; Pancreatic Polypeptide-Secreting Cells; Transplantation, Autologous

Selective glucocorticoid receptor modulators (GRMs) promise to reduce adverse events of glucocorticoids while maintaining anti-inflammatory potency. The present study tested the anti-inflammatory activity of two novel non-steroidal GRMs (GRM1: BI 607812 BS, GRM2: BI 653048 BS*H3PO4) in comparison to prednisolone in a canine model of low dose endotoxemia. This study compared the anti-inflammatory and pharmacokinetic profile of escalating daily oral doses of GRM1 (1, 2.5, 5 and 10mg/kg) and GRM2 (0.1, 0.25 and 1mg/kg) with prednisolone (0.25 and 0.5mg/kg) and placebo after intravenous infusion of endotoxin (0.1μg/kg) to Beagle dogs. This was followed by a 14-day evaluation study of safety and pharmacokinetics. Endotoxin challenge increased TNF-α ∼2000-fold and interleukin-6 (IL-6) 100-fold. Prednisolone and both GRMs suppressed peak TNF-α and IL-6 by 71-82% as compared with placebo. The highest doses of GRM1 and GRM2 reduced the mean body temperature increase by ∼30%. The endotoxin-induced rise in plasma cortisol was strongly suppressed in all treatment groups. Pharmacokinetics of both GRMs were non-linear. Adverse effects of endotoxemia such as vomiting were mitigated by GRM2 and prednisolone, indicating an antiemetic effect. During the 14-day treatment period, the adverse event profile of both GRMs appeared to be similar to prednisolone. Both GRMs had anti-inflammatory effects comparable to prednisolone and showed good safety profiles. Compounds targeting the glucocorticoid receptor selectively may provide an alternative to traditional glucocorticoids in the treatment of inflammatory disease.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Benzamides; Bone and Bones; C-Peptide; Cytokines; Disease Models, Animal; Dogs; Endotoxemia; Insulin; Male; Osteocalcin; Pyridines; Pyrimidines; Pyrroles; Receptors, Glucocorticoid

Individuals with metabolic syndrome (MS) show several metabolic abnormalities including insulin resistance, dyslipidaemia, and oxidative stress (OS). Diet is one of the factors influencing the development of MS, and current nutritional advice emphasises the benefits of fruit and vegetable consumption. Here, we assessed the effects of naturally occurring antioxidants, red wine polyphenols (RWPs), on MS and OS.. Wistar rats (n = 20) weighing 200-220 g received a high-fat diet (HFD) for 2 months before they were divided into two groups that received either HFD only or HFD plus 50 mg/kg RWPs in their drinking water for an additional 2 months. A control group (n = 10) received a normal diet (ND) for 4 months.. Rats receiving HFD increased body weight over 20 % throughout the duration of the study. They also showed increased blood levels of C-peptide, glucose, lipid peroxides, and oxidised proteins. In addition, the HFD increased OS in hepatic, pancreatic, and vascular tissues, as well as induced pancreatic islet cell hyperplasia and hepatic steatosis. Addition of RWPs to the HFD attenuated these effects on plasma and tissue OS and on islet cell hyperplasia. However, RWPs had no effect on blood glucose levels or hepatic steatosis.. RWPs showed an antioxidant mechanism of action against MS. This result will inform future animal studies exploring the metabolic effects of RWPs in more detail. In addition, these findings support the use of antioxidants as adjunctive nutritional treatments for patients with diabetes.

Topics: Animals; Antioxidants; Blood Glucose; C-Peptide; Diet, High-Fat; Disease Models, Animal; Lipid Peroxides; Liver; Male; Metabolic Syndrome; Oxidative Stress; Polyphenols; Rats; Rats, Wistar; Wine

We previously demonstrated that polymorphisms in the carnosinase-1 gene (CNDP1) determine the risk of nephropathy in type 2 diabetic patients. Carnosine, the substrate of the enzyme encoded by this gene, is considered renoprotective and could possibly be used to treat diabetic nephropathy (DN). In this study, we examined the effect of carnosine treatment in vivo in BTBR (Black and Tan, BRachyuric) ob/ob mice, a type 2 diabetes model which develops a phenotype that closely resembles advanced human DN. Treatment of BTBR ob/ob mice with 4 mM carnosine for 18 weeks reduced plasma glucose and HbA1c, concomitant with elevated insulin and C-peptide levels. Also, albuminuria and kidney weights were reduced in carnosine-treated mice, which showed less glomerular hypertrophy due to a decrease in the surface area of Bowman's capsule and space. Carnosine treatment restored the glomerular ultrastructure without affecting podocyte number, resulted in a modified molecular composition of the expanded mesangial matrix and led to the formation of carnosine-acrolein adducts. Our results demonstrate that treatment with carnosine improves glucose metabolism, albuminuria and pathology in BTBR ob/ob mice. Hence, carnosine could be a novel therapeutic strategy to treat patients with DN and/or be used to prevent DN in patients with diabetes.

Topics: Administration, Oral; Albuminuria; Animals; Blood Glucose; C-Peptide; Carnosine; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Dipeptidases; Disease Models, Animal; Gene Expression; Glomerular Mesangium; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Kidney Glomerulus; Male; Mice; Mice, Obese; Organ Size

Gastric bypass surgery produces clear antidiabetic effects in a substantial proportion of morbidly obese patients. In view of the recent trend away from 'bariatric' surgery and toward 'metabolic' surgery, it is important to elucidate the enhancing effect of bypass surgery on pancreatic β-cell mass, which is related to diabetes remission in non-obese patients. We investigated the effects of gastric bypass surgery on glycemic control and other pancreatic changes in a spontaneous non-obese type 2 diabetes Goto-Kakizaki rat model. Significant improvements in postprandial hyperglycemia and plasma c-peptide level were observed when glucose was administered orally post-surgery. Other important events observed after surgery were enhanced first phase insulin secretion in a in site pancreatic perfusion experiment, pancreatic hyperplasia, improved islet structure (revealed by immunohistochemical analysis), striking increase in β-cell mass, slight increase in ratio of β-cell area to total pancreas area, and increased number of small islets closely related to exocrine ducts. No notable changes were observed in ratio of β-cell to non-β endocrine cell area, β-cell apoptosis, or β-cell proliferation. These findings demonstrate that gastric bypass surgery in this rat model increases endocrine cells and pancreatic hyperplasia, and reflect the important role of the gastrointestinal system in regulation of metabolism.

Topics: Animals; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Disease Models, Animal; Fasting; Gastric Bypass; Gastric Inhibitory Polypeptide; Glucose Tolerance Test; Hyperglycemia; Hyperplasia; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Pancreas; Rats; Rats, Wistar

The transplantation of glucose-responsive, insulin-producing cells offers the potential for restoring glycemic control in individuals with diabetes. Pancreas transplantation and the infusion of cadaveric islets are currently implemented clinically, but these approaches are limited by the adverse effects of immunosuppressive therapy over the lifetime of the recipient and the limited supply of donor tissue. The latter concern may be addressed by recently described glucose-responsive mature beta cells that are derived from human embryonic stem cells (referred to as SC-β cells), which may represent an unlimited source of human cells for pancreas replacement therapy. Strategies to address the immunosuppression concerns include immunoisolation of insulin-producing cells with porous biomaterials that function as an immune barrier. However, clinical implementation has been challenging because of host immune responses to the implant materials. Here we report the first long-term glycemic correction of a diabetic, immunocompetent animal model using human SC-β cells. SC-β cells were encapsulated with alginate derivatives capable of mitigating foreign-body responses in vivo and implanted into the intraperitoneal space of C57BL/6J mice treated with streptozotocin, which is an animal model for chemically induced type 1 diabetes. These implants induced glycemic correction without any immunosuppression until their removal at 174 d after implantation. Human C-peptide concentrations and in vivo glucose responsiveness demonstrated therapeutically relevant glycemic control. Implants retrieved after 174 d contained viable insulin-producing cells.

Topics: Alginates; Animals; Blood Glucose; Blotting, Western; C-Peptide; Cell Culture Techniques; Cell Differentiation; Cell Transplantation; Chromatography, Liquid; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 1; Disease Models, Animal; Embryonic Stem Cells; Flow Cytometry; Fluorescent Antibody Technique; Foreign-Body Reaction; Humans; Hydrogels; Immunocompetence; Insulin; Insulin-Secreting Cells; Mice; Microscopy, Confocal; Microscopy, Phase-Contrast; Morpholines; Polymers; Tandem Mass Spectrometry; Triazoles

This paper aimed to assess the physiological effects of p53 on glucose homeostasis in vivo.. A recombinant adenoviral p53 (rAd-p53) vector was administered to insulin-resistant diabetic mice. Intraperitoneal glucose tolerance test was performed in all groups of mice. Changes in fasting blood glucose, serum triglycerides, C-peptide, and insulin concentrations in treated and untreated mice were measured. Analyses of the target genes related to glucose metabolism were performed.. Treatment with the rAd-p53 improved glucose control in a dose- and time-dependent manner and lowered significantly the fasting blood glucose, the serum triglycerides, and improved tolerance test of glucose as compared to control. Lowered blood glucose was associated with up-regulation of genes in the glycogenesis pathways, and down-regulation of genes in the gluconeogenesis pathways in the liver. Overexpressions of GLUT2, GK, PPAR-γ, and insulin receptor precursor were also observed in the liver and the pancreas of treated animals.. Activation of p53-mediated glucose metabolism led to insulin-like antidiabetic effect in the mouse model especially by changing hepatic insulin sensitivity in the diabetic mouse model.

Topics: Animals; Blood Glucose; Blotting, Western; C-Peptide; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Diet, High-Fat; Disease Models, Animal; Gene Expression; Gluconeogenesis; Glucose Transporter Type 2; Humans; Insulin; Insulin Resistance; Male; Mice, Inbred BALB C; PPAR gamma; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction; Triglycerides; Tumor Suppressor Protein p53; Up-Regulation

It is widely accepted that lifestyle plays a crucial role on the quality of life in individuals, particularly in western societies where poor diet is correlated to alterations in behavior and the increased possibility of developing type-2 diabetes. While exercising is known to produce improvements to overall health, there is conflicting evidence on how much of an effect exercise has staving off the development of type-2 diabetes or counteracting the effects of diet on anxiety. Thus, this study investigated the effects of voluntary wheel-running access on the progression of diabetes-like symptoms and open field and light-dark box behaviors in C57BL/6J mice fed a high-fat diet. C57BL/6J mice were placed into either running-wheel cages or cages without a running-wheel, given either regular chow or a high-fat diet, and their body mass, food consumption, glucose tolerance, insulin and c-peptide levels were measured. Mice were also exposed to the open field and light-dark box tests for anxiety-like behaviors. Access to a running-wheel partially attenuated the obesity and hyperinsulinemia associated with high-fat diet consumption in these mice, but did not affect glucose tolerance or c-peptide levels. Wheel-running strongly increased anxiety-like and decreased explorative-like behaviors in the open field and light-dark box, while high-fat diet consumption produced smaller increases in anxiety. These results suggest that voluntary wheel-running can assuage some, but not all, of the physiological problems associated with high-fat diet consumption, and can modify anxiety-like behaviors regardless of diet consumed.

Topics: Animals; Anxiety; C-Peptide; Diabetes Mellitus, Type 2; Diet, High-Fat; Disease Models, Animal; Eating; Exploratory Behavior; Insulin; Male; Mice, Inbred C57BL; Obesity; Running; Volition; Weight Gain

In this study, we observed a great reduction in the expression of the endogenous long noncoding RNA ROR (lncRNA-ROR) and the stem cell transcription factor Sox2, in contrast to a marked increase in miR-145 expression, during the course of in vitro induced differentiation of human amniotic epithelial stem cells (HuAECs). Bioinformatics analysis and the luciferase reporter assay revealed binding of miR-145 to specific sites in lncRNA-ROR and Sox2, silencing their expression. Overexpression of a lncRNA-ROR-specific siRNA effectively downregulated the expression levels of Sox2 and other stem cell markers in HuAECs while weakening the efficiency of HuAEC differentiation into β islet-like cells. Moreover, the in vitro response of HuAEC-derived β islet-like cells to extracellular stimuli and C-peptide release by these cells were markedly weakened in the siRNA-ROR transfection group. Furthermore, the in vivo expression of β islet-like cell biomarkers was substantially reduced in HuAECs in the siRNA-ROR transfection group, and their in vivo β islet-like cell differentiation and insulin release capacities were reduced in a streptozocin-induced diabetic rat model. The experimental results indicate that lncRNA-ROR effectively maintains Sox2 gene expression through competitive binding to miR-145, achieving pluripotency maintenance in HuAECs and regulation of their directed β islet-like cell differentiation efficiency.

Topics: Amnion; Animals; Biomarkers; C-Peptide; Cell Differentiation; Diabetes Mellitus, Experimental; Disease Models, Animal; Epithelial Cells; Fluorescent Antibody Technique; Gene Expression Regulation; Humans; Insulin-Secreting Cells; Islets of Langerhans Transplantation; Mice; MicroRNAs; Pluripotent Stem Cells; Rats; RNA, Long Noncoding; SOXB1 Transcription Factors; Streptozocin

Mesenchymal stem cells (MSCs) transplantation is a promising therapeutic strategy for type 1 diabetes (T1D). However, little is known on whether MSC transplantation can benefit T1D patients with ketoacidosis and its potential actions. Here, we show that infusion with bone marrow MSCs preserves β-cell function in some T1D patients with ketoacidosis by decreasing exogenous insulin requirement and increasing plasma C-peptide levels up to 1-2 years. MSC transplantation increased plasma and islet insulin contents in non-obese diabetic (NOD) mice with severe diabetes. In comparison with severe diabetes controls, MSC infusion reduced insulitis, decreased pancreatic TNF-α, and increased IL-10 and TGF-β1 expression in NOD mice. MSC infusion increased the percentages of splenic Tregs and levels of plasma IL-4, IL-10 and TGF-β1, but reduced the percentages of splenic CD8

Topics: Adolescent; Adult; Animals; B-Lymphocytes; Bone Marrow Cells; C-Peptide; CD8-Positive T-Lymphocytes; Cytokines; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 1; Disease Models, Animal; Female; Humans; Inflammation; Insulin-Secreting Cells; Interleukin-10; Ketosis; Male; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Mice; Mice, Inbred C57BL; Mice, Inbred NOD; Pancreas; Spleen; T-Lymphocytes, Regulatory; Transforming Growth Factor beta1; Tumor Necrosis Factor-alpha; Young Adult

Anti-tumor necrosis factor-α (TNF-α) therapy (5 mg/kg body weight), alone or combined with the T-cell-specific antibody anti-T-cell receptor (TCR) (0.5 mg/kg body weight), was performed over 5 days immediately after disease manifestation to reverse the diabetic metabolic state in the LEW.1AR1-iddm rat, an animal model of human type 1 diabetes. Only combination therapy starting at blood glucose concentrations below 15 mmol/L restored normoglycemia and normalized C-peptide. Increased β-cell proliferation and reduced apoptosis led to a restoration of β-cell mass along with an immune cell infiltration-free pancreas 60 days after the end of therapy. This combination of two antibodies, anti-TCR/CD3, as a cornerstone compound in anti-T-cell therapy, and anti-TNF-α, as the most prominent and effective therapeutic antibody in suppressing TNF-α action in many autoimmune diseases, was able to reverse the diabetic metabolic state. With increasing blood glucose concentrations during the disease progression, however, the proapoptotic pressure on the residual β-cell mass increased, ultimately reaching a point where the reservoir of the surviving β-cells was insufficient to allow a restoration of normal β-cell mass through regeneration. The present results may open a therapeutic window for reversal of diabetic hyperglycemia in patients, worthwhile of being tested in clinical trials.

Topics: Animals; Antibodies, Monoclonal; Blood Glucose; C-Peptide; Cell Proliferation; Diabetes Mellitus, Type 1; Disease Models, Animal; Insulin; Male; Rats; Rats, Inbred Lew; T-Lymphocytes; Tumor Necrosis Factor-alpha

A C-peptide-based assessment of β-cell function was performed here in the Zucker fatty rat, a suitable animal model of human metabolic syndrome. To this aim, a 90-min intravenous glucose tolerance test (IVGTT) was performed in seven Zucker fatty rats (ZFR), 7-to-9 week-old, and seven age-matched Zucker lean rats (ZLR). The minimal model of C-peptide (CPMM), originally introduced for humans, was adapted to Zucker rats and then applied to interpret IVGTT data. For a comprehensive evaluation of glucose tolerance in ZFR, CPMM was applied in combination with the minimal model of glucose kinetics (GKMM). Our results showed that the present CPMM-based interpretation of data is able to: 1) provide a suitable fit of C-Peptide data; 2) achieve a satisfactory estimation of parameters of interest 3) quantify both insulin secretion by estimating the time course of pre-hepatic secretion rate, SR(t), and total insulin secretion, TIS, and pancreatic sensitivity by means of three specific indexes of β-cell responsiveness to glucose stimulus (first-phase, Ф(1), second-phase, Ф(2), and steady-state, Ф(ss), never assessed in Zucker rats before; 4) detect the significant enhancement of insulin secretion in the ZFR, in face of a severe insulin-resistant state, previously observed only using a purely experimental approach. Thus, the methodology presented here represents a reliable tool to assess β-cell function in the Zucker rat, and opens new possibilities for the quantification of further processes involved in glucose homeostasis such as the hepatic insulin degradation.

Topics: Animals; Blood Glucose; C-Peptide; Disease Models, Animal; Glucose; Glucose Tolerance Test; Insulin; Insulin Secretion; Insulin-Secreting Cells; Male; Rats; Rats, Zucker; Time Factors

Type 2 diabetes mellitus is the most common endocrine disease all over the world, while existing therapies can only ameliorate hyperglycemia or temporarily improve the response to insulin in target tissues, they cannot retard or improve the progressive β-cell dysfunction persistently. Combined therapy of stem cells and sitagliptin might resolve this problem, we verified this hypothesis in a diabetic rat model. Except ten Wistar rats in normal control group, diabetic rats were divided into diabetic control group, WJ-MSCs group, sitagliptin group and WJ-MSCs + sitagliptin group and received homologous therapy. Ten weeks after therapy, diabetic symptoms, FPG and GHbA1c in WJ-MSCs group, sitagliptin group and WJ-MSCs + sitagliptin group were significantly less than those in diabetic control group (P < 0.05), while fasting C-peptide and number of β cells in WJ-MSCs group and WJ-MSCs + sitagliptin group was significantly higher than those in diabetic control and sitagliptin group (P < 0.01). Glucagon and number of α cells in sitagliptin group and WJ-MSCs + sitagliptin group were significantly lower than those in WJ-MSCs group and diabetic control group (P < 0.01). No symptoms of rejection and toxic effect were observed. Combined therapy of WJ-MSCs and sitagliptin can effectively ameliorate hyperglycemia, promote regeneration of islet β cells and suppress generation of islet α cells in diabetic rats, presenting a new therapy for type 2 diabetes although the exact mechanisms are unclear.

Topics: Animals; C-Peptide; Cell Proliferation; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Disease Models, Animal; Glucagon; Glycated Hemoglobin; Hypoglycemic Agents; Insulin; Insulin-Secreting Cells; Male; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Pyrazines; Rats; Rats, Wistar; Sitagliptin Phosphate; Streptozocin; Treatment Outcome; Triazoles; Umbilical Cord

Excessive generation of reactive oxygen species (ROS) causing oxidative stress plays a major role in the pathogenesis of diabetes by inducing beta cell secretory dysfunction and apoptosis. Recent evidence has shown that C-peptide, produced by beta cells and co-secreted with insulin in the circulation of healthy individuals, decreases ROS and prevents apoptosis in dysfunctional vascular endothelial cells. In this study, we tested the hypothesis that an autocrine activity of C-peptide similarly decreases ROS when INS1 beta cells are exposed to stressful conditions of diabetes.. Reactive oxygen species and apoptosis were induced in INS1 beta cells pretreated with C-peptide by either 22 mM glucose or 100 μM hydrogen peroxide (H2 O2 ). To test C-peptide's autocrine activity, endogenous C-peptide secretion was inhibited by the KATP channel opener diazoxide and H2 O2 -induced ROS assayed after addition of either exogenous C-peptide or the secretagogue glibenclamide. In similar experiments, extracellular potassium, which depolarizes the membrane otherwise hyperpolarized by diazoxide, was used to induce endogenous C-peptide secretion. ROS was measured using the cell-permeant dye chloromethyl-2',7'-dichlorodihydrofluorescein diacetate (CM-H2 -DCFDA). Insulin secretion and apoptosis were assayed by enzyme-linked immunosorbent assay.. C-peptide significantly decreased high glucose-induced and H2 O2 -induced ROS and prevented apoptosis of INS1 beta cells. Diazoxide significantly increased H2 O2 -induced ROS, which was reversed by exogenous C-peptide or glibenclamide or potassium chloride.. These findings demonstrate an autocrine C-peptide mechanism in which C-peptide is bioactive on INS1 beta cells exposed to stressful conditions and might function as a natural antioxidant to limit beta cell dysfunction and loss contributing to diabetes.

Topics: Adaptation, Physiological; Animals; Apoptosis; Autocrine Communication; C-Peptide; Cell Line, Tumor; Diazoxide; Disease Models, Animal; Glucose; Glyburide; Hydrogen Peroxide; Hypoglycemic Agents; Insulin-Secreting Cells; Insulinoma; Oxidative Stress; Pancreatic Neoplasms; Potassium Chloride; Rats; Reactive Oxygen Species

Human pancreatic islet transplantation is a prospective curative treatment for diabetes. However, the lack of donor pancreases greatly limits this approach. One approach to overcome the limited supply of donor pancreases is to generate functional islets from human embryonic stem cells (hESCs), a cell line with unlimited proliferative capacity, through rapid directed differentiation. This study investigated whether pancreatic insulin-producing cells (IPCs) differentiated from hESCs could correct hyperglycemia in severe combined immunodeficient (SCID)/non-obese diabetic (NOD) mice, an animal model of diabetes.. We generated pancreatic IPCs from two hESC lines, YT1 and YT2, using an optimized four-stage differentiation protocol in a chemically defined culture system. Then, about 5-7 × 10(6) differentiated cells were transplanted into the epididymal fat pad of SCID/NOD mice (n = 20). The control group were transplanted with undifferentiated hESCs (n = 6). Graft survival and function were assessed using immunohistochemistry, and measuring serum human C-peptide and blood glucose levels.. The pancreatic IPCs were generated by the four-stage differentiation protocol using hESCs. About 17.1% of differentiated cells expressed insulin, as determined by flow cytometry. These cells secreted insulin/C-peptide following glucose stimulation, similarly to adult human islets. Most of these IPCs co-expressed mature β cell-specific markers, including human C-peptide, GLUT2, PDX1, insulin, and glucagon. After implantation into the epididymal fat pad of SCID/NOD mice, the hESC-derived pancreatic IPCs corrected hyperglycemia for ≥ 8 weeks. None of the animals transplanted with pancreatic IPCs developed tumors during the time. The mean survival of recipients was increased by implanted IPCs as compared to implanted undifferentiated hESCs (P<0.0001).. The results of this study confirmed that human terminally differentiated pancreatic IPCs derived from hESCs can correct hyperglycemia in SCID/NOD mice for ≥8 weeks.

Topics: Animals; Blood Glucose; C-Peptide; Cell Differentiation; Diabetes Mellitus, Experimental; Disease Models, Animal; Embryonic Stem Cells; Humans; Insulin; Insulin Secretion; Insulin-Secreting Cells; Islets of Langerhans Transplantation; Mice; Mice, Inbred NOD; Pancreas

Compelling evidence indicates that polyphenolic antioxidants show protective effects against diabetic complications. We investigated the effects of a polyphenolic compound, 7-O-galloyl-D-sedoheptulose (GS), from Corni Fructus on a type 2 diabetic db/db mouse model. After 6 weeks of GS treatment, the effects of GS on serum and pancreatic biochemical factors were investigated. To define the underlying mechanism of these effects, we examined several key inflammatory markers, and inflammation-related oxidative stress markers. The results showed that levels of glucose, leptin, insulin, C-peptide, resistin, tumor necrosis factor-α, and interleukin-6 in serum were down-regulated, while adiponectin was augmented by GS treatment. In addition, GS suppressed reactive oxygen species and lipid peroxidation in the pancreas, but increased the pancreatic insulin and pancreatic C-peptide contents. Moreover, GS modulated protein expressions of pro-inflammatory nuclear factor-kappa Bp 65, cyclooxygenase-2, inducible nitric oxide synthase, c-Jun N-terminal kinase (JNK), phospho-JNK, activator protein-1, transforming growth factor-β1, and fibronectin. Based on these results, we conclude that a plausible mechanism of GS's anti-diabetic action may well be its anti-inflammatory property and anti-inflammatory-related anti-oxidative action. Thus, further investigation of GS as an effective anti-diabetic treatment for type 2 diabetes is warranted.

Topics: Animals; Anti-Inflammatory Agents; Blood Glucose; C-Peptide; Cornus; Cytokines; Diabetes Mellitus, Type 2; Disease Models, Animal; Fibronectins; Heptoses; Hypoglycemic Agents; Insulin; JNK Mitogen-Activated Protein Kinases; Male; Mice; Oxidative Stress; Pancreas; Reactive Oxygen Species; Thiobarbituric Acid Reactive Substances; Transcription Factor AP-1

Previously, we screened a proteoglycan for anti-hyperglycemic, named FYGL, from Ganoderma Lucidum. For further research of the antidiabetic mechanisms of FYGL in vivo, the glucose homeostasis, activities of insulin-sensitive enzymes, glucose transporter expression and pancreatic function were analyzed using db/db mice as diabetic models in the present work. FYGL not only lead to a reduction in glycated hemoglobin level, but also an increase in insulin and C-peptide level, whereas a decrease in glucagons level and showed a potential for the remediation of pancreatic islets. FYGL also increased the glucokinase activities, and simultaneously lowered the phosphoenol pyruvate carboxykinase activities, accompanied by a reduction in the expression of hepatic glucose transporter protein 2, while the expression of adipose and skeletal glucose transporter protein 4 was increased. Moreover, the antioxidant enzyme activities were also increased by FYGL treatment. Thus, FYGL was an effective antidiabetic agent by enhancing insulin secretion and decreasing hepatic glucose output along with increase of adipose and skeletal muscle glucose disposal in the late stage of diabetes. Furthermore, FYGL is beneficial against oxidative stress, thereby being helpful in preventing the diabetic complications.

Topics: Animals; Antioxidants; Biological Factors; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Disease Models, Animal; Glucokinase; Glucose; Glucose Transporter Type 2; Glucose Transporter Type 4; Glycated Hemoglobin; Hypoglycemic Agents; Hypolipidemic Agents; Insulin; Insulin Resistance; Islets of Langerhans; Liver; Male; Mice; Mice, Inbred C57BL; Muscle, Skeletal; Oxidative Stress; Phosphoenolpyruvate Carboxykinase (ATP); Proteoglycans; Reishi

To characterise changes in pancreatic beta cell mass during the development of diabetes in untreated male C57BLKS/J db/db mice.. Blood samples were collected from a total of 72 untreated male db/db mice aged 5, 6, 8, 10, 12, 14, 18, 24 and 34 weeks, for measurement of terminal blood glucose, HbA1c, plasma insulin, and C-peptide. Pancreata were removed for quantification of beta cell mass, islet numbers as well as proliferation and apoptosis by immunohistochemistry and stereology.. Total pancreatic beta cell mass increased significantly from 2.1 ± 0.3 mg in mice aged 5 weeks to a peak value of 4.84 ± 0.26 mg (P < 0.05) in 12-week-old mice, then gradually decreased to 3.27 ± 0.44 mg in mice aged 34 weeks. Analysis of islets in the 5-, 10-, and 24-week age groups showed increased beta cell proliferation in the 10-week-old animals whereas a low proliferation is seen in older animals. The expansion in beta cell mass was driven by an increase in mean islet mass as the total number of islets was unchanged in the three groups.. The age-dependent beta cell dynamics in male db/db mice has been described from 5-34 weeks of age and at the same time alterations in insulin/glucose homeostasis were assessed. High beta cell proliferation and increased beta cell mass occur in young animals followed by a gradual decline characterised by a low beta cell proliferation in older animals. The expansion of beta cell mass was caused by an increase in mean islet mass and not islet number.

Topics: Age Factors; Animals; Apoptosis; Blood Glucose; C-Peptide; Cell Proliferation; Diabetes Mellitus, Type 2; Disease Models, Animal; Fasting; Insulin; Insulin-Secreting Cells; Islets of Langerhans; Male; Mice

To investigate the effect of novel probiotics on the clinical characteristics of high-fructose induced metabolic syndrome.. Male Wistar rats aged 4 wk were fed a 70% w/w high-fructose diet (n = 27) or chow diet (n = 9) for 3 wk to induce metabolic syndrome, the rats were then randomized into groups and administered probiotic [Lactobacillus curvatus (L. curvatus) HY7601 and Lactobacillus plantarum (L. plantarum) KY1032] at 10(9) cfu/d or 10(10) cfu/d or placebo by oral gavage for 3 wk. Food intake and body weight were measured once a week. After 6 wk, the rats were fasted for 12 h, then anesthetized with diethyl ether and sacrificed. Blood samples were taken from the inferior vena cava for plasma analysis of glucose, insulin, C-peptide, total-cholesterol, triglycerides and thiobarbituric acid-reacting substances. Real-time polymerase chain reaction was performed using mouse-specific Taqman probe sets to assess genes related to fatty acid β-oxidation, lipogenesis and cholesterol metabolism in the liver. Target gene expression was normalized to the housekeeping gene, glyceraldehyde-3-phosphate dehydrogenase.. Rodents fed a high-fructose diet developed clinical characteristics of the metabolic syndrome including increased plasma glucose, insulin, triglycerides, total cholesterol and oxidative stress levels, as well as increased liver mass and liver lipids compared to chow fed controls. Probiotic treatment (L. curvatus HY7601 and L. plantarum KY1032) at high (10(10) cfu/d) or low dosage (10(9) cfu/d) lowered plasma glucose, insulin, triglycerides and oxidative stress levels. Only high-dose probiotic treatment reduced liver mass and liver cholesterol. Probiotic treatment reduced lipogenesis via down-regulation of SREBP1, FAS and SCD1 mRNA levels and increased β-oxidation via up-regulation of PPARα and CPT2 mRNA levels.. Probiotic L. curvatus HY7601 and L. plantarum KY1032 combined suppressed the clinical characteristics of high-fructose-induced metabolic syndrome, therefore, may provide a natural alternative for the treatment of diet-induced metabolic syndrome.

Topics: Animals; Blood Glucose; C-Peptide; Cholesterol; Dietary Carbohydrates; Disease Models, Animal; Fructose; Insulin; Lactobacillus; Male; Metabolic Syndrome; Oxidative Stress; Probiotics; Rats; Thiobarbituric Acid Reactive Substances; Triglycerides

Patients with insulin resistance and early type 2 diabetes exhibit an increased propensity to develop a diffuse and extensive pattern of arteriosclerosis. Typically, these patients show elevated serum levels of the proinsulin cleavage product C-peptide and immunohistochemical data from our group revealed C-peptide deposition in early lesions of these individuals. Moreover, in vitro studies suggest that C-peptide could promote atherogenesis. This study examined whether C-peptide promotes vascular inflammation and lesion development in a mouse model of arteriosclerosis. ApoE-deficient mice on a high fat diet were treated with C-peptide or control injections for 12 weeks and the effect on lesion size and plaque composition was analysed. C-peptide treatment significantly increased C-peptide blood levels by 4.8-fold without having an effect on glucose or insulin levels, nor on the lipid profile. In these mice, C-peptide deposition in atherosclerotic plaques was significantly increased compared with controls. Moreover, lesions of C-peptide-treated mice contained significantly more macrophages (1.6 ± 0.3% versus 0.7 ± 0.2% positive area; P < 0.01) and more vascular smooth muscle cells (4.8 ± 0.6% versus 2.4 ± 0.3% positive area; P < 0.01). Finally, lipid deposition measured by Oil-red-O staining in the aortic arch was significantly higher in the C-peptide group compared with controls. Our results demonstrate that elevated C-peptide levels promote inflammatory cell infiltration and lesion development in ApoE-deficient mice without having metabolic effects. These data obtained in a mouse model of arteriosclerosis support the hypothesis that C-peptide may have an active role in atherogenesis in patients with diabetes and insulin resistance.

Topics: Amino Acid Sequence; Animals; Apolipoproteins E; Arteriosclerosis; C-Peptide; Disease Models, Animal; In Vitro Techniques; Macrophages; Mice; Mice, Knockout; Molecular Sequence Data

Heterozygous male Munich Ins2(C95S) mutant mice, a model for permanent neonatal diabetes mellitus, demonstrate a progressive diabetic phenotype with severe loss of functional beta cell mass. The aim of this study was to investigate the influence of early insulin treatment on glucose homeostasis and beta cell destruction in male Munich Ins2(C95S) mutants.. One group of male Ins2(C95S) mutants was treated with subcutaneous insulin pellets, as soon as blood glucose levels began to rise; placebo-treated mutants and wild-type mice served as controls. An additional group of mutant mice received a sodium-dependent glucose transporter 2 (SGLT2) inhibitor (AVE2268) via rodent chow.. Insulin treatment normalised blood glucose concentrations, improved oral glucose tolerance, preserved insulin sensitivity and inhibited oxidative stress of Munich Ins2(C95S) mutant mice. Pancreatic C-peptide content, as well as total beta cell and isolated beta cell volumes, of insulin-treated mutant mice were higher than those of placebo-treated mutants. In addition, alpha cell dysfunction and hyperplasia of non-beta cells were completely normalised in insulin-treated mutant mice. Treatment with the SGLT2 inhibitor lowered blood glucose, improved glucose tolerance and normalised insulin sensitivity as well as oxidative stress of Ins2(C95S) mutants. The abundance of the endoplasmic reticulum (ER) stress markers binding Ig protein (BiP) and phosphorylated eukaryotic translation initiation factor 2 alpha (P-eIF2α) was significantly increased in the islets of mutants, before onset of hyperglycaemia, vs wild-type mice.. We conclude that early insulin treatment protects Munich Ins2(C95S) mutant mice from insulin resistance, alpha cell hyperfunction, beta cell loss and hyperplasia of non-beta cells, some well-known features of human diabetes mellitus. Therefore, insulin treatment may be considered early for human patients harbouring INS mutations.

Topics: Animals; Animals, Newborn; C-Peptide; Diabetes Mellitus; Disease Models, Animal; Endoplasmic Reticulum; Glucose; Homeostasis; Insulin; Insulin-Secreting Cells; Male; Mice; Oxidative Stress; Pancreas; Phenotype; Placebos; Sodium-Glucose Transporter 2

The aim of the present study was to determine the effects of a cafeteria diet on the function and apoptosis of the pancreas, and the activity and expression of the insulin-degrading enzyme (IDE). Female Wistar rats were fed either with a cafeteria diet or a control diet for 17 weeks, and blood and tissues were then collected for analysis. The cafeteria diet-treated rats had higher plasma insulin and C-peptide levels (P<0·05), showing increased insulin secretion by the pancreas. Insulin protein and gene expression levels were higher in the pancreas of obese rats, as was its transcriptional controller, pancreatic duodenal homeobox 1 (P<0·05). Feeding a cafeteria diet down-regulated the gene expression of the anti-apoptotic marker B-cell/lymphoma 2 (BCL2), and up-regulated the protein levels of BCL2-associated X protein, a pro-apoptotic marker (P<0·05). The cafeteria diet caused lipid accumulation in the pancreas and modified the expression of key genes that control lipid metabolism. To assay whether insulin clearance was also modified, we checked the activity of the IDE, one of the enzymes responsible for insulin clearance. We found increased liver IDE activity (P<0·05) in the cafeteria diet-fed animals, which could, in part, be due to an up-regulation of its gene expression. Conversely, IDE gene expression was unmodified in the kidney and adipose tissue; although when the adipose tissue weight was considered, the insulin clearance potential was higher in the cafeteria diet-treated rats. In conclusion, treatment with a cafeteria diet for 17 weeks in rats mimicked a pre-diabetic state, with ectopic lipid accumulation in the pancreas, and increased the IDE-mediated insulin clearance capability.

Topics: Animals; Apoptosis; bcl-2-Associated X Protein; C-Peptide; Diet, High-Fat; Disease Models, Animal; Female; Gene Expression Regulation; Homeodomain Proteins; Hyperinsulinism; Insulin; Insulin Resistance; Insulysin; Liver; Organ Specificity; Pancreas; Prediabetic State; Proto-Oncogene Proteins c-bcl-2; Rats; Rats, Wistar; RNA, Messenger; Trans-Activators; Triglycerides

In the present study, we examined the therapeutic potential of human amnion-derived insulin-secreting cells for type 1 diabetes. Human amniotic mesenchymal stem cells (hAMs) were isolated from amnion and cultivated to differentiate into insulin-secreting cells in vitro. After culture in vitro, the differentiated cells (hAM-ISCs) were intensively stained with dithizone and secreted insulin and c-peptide in a high-glucose-dependent manner. They expressed mRNAs of pancreatic cell-related genes, including INS, PDX1, Nkx6-1, NEUROG3, ISL1, NEUROD1, GLUT1, GLUT2, PC1/3, PC2, GCK, PPY, SST, and GC, and were positive for human insulin and c-peptide. Transplantation of hAM-ISCs into the kidneys of mice with streptozotocin-induced diabetes restored body weight and normalized the blood glucose levels, which lasted for 210 days. Only human insulin and c-peptide were detected in the blood of normalized mice after 2 months of transplantation, but little mouse insulin and c-peptide. Removal of graft-bearing kidneys from these mice resulted in causing hyperglycemia again. Human cell-specific gene, hAlu, and human pancreatic cell-specific genes, insulin, PDX1, GLUT1, GLP1R, Nkx6-1, NEUROD1, and NEUROG3, were detected in the graft-bearing kidneys. Colocalization of human insulin and human nuclei antigen was also observed. These results demonstrate that hAMs could differentiate into functional insulin-secreting cells in vitro, and human insulin secreted from hAM-ISCs following transplantation into type 1 diabetic mice could normalize hyperglycemia, overcoming immune rejection for a long period.

Topics: Animals; Blood Glucose; C-Peptide; Cell Differentiation; Cells, Cultured; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 1; Disease Models, Animal; Female; Humans; Hyperglycemia; Immunohistochemistry; Insulin; Insulin Secretion; Insulin-Secreting Cells; Mesenchymal Stem Cells; Mice; Mice, Inbred C57BL; Transplantation, Heterologous

Juvenile (2-23 years old) cynomolgus monkeys are frequently used as recipients in non-human primate islet transplantation studies. The aim of this study was to examine the effects of different doses of streptozotocin (STZ), and find the optimal dose for inducing diabetes in these monkeys. Fifteen juvenile (2-3 years old) cynomolgus monkeys were separated into three groups and administered with different doses of STZ (100, 68 or 60 mg kg(-1)). Basal and glucose-stimulated blood glucose, insulin, and C-peptide levels, as well as body weights were monitored. Hepatic and renal function tests and pancreatic immunohistochemistry were performed before and after STZ treatment. Monkeys treated with both 100 and 68 mg kg(-1) of STZ exhibited continuous hyperglycemia, which coincided with a nearly complete loss of islet β-cells. Two monkeys received 60 mg kg(-1) of STZ, but only one became completely diabetic. During the first week following STZ treatment, hepatic and renal function slightly increased in these three groups. However, 24 hours post-STZ, serum total bile acid levels were significantly increased in monkeys treated with 100 mg kg(-1) than those treated with 68 mg kg(-1) of STZ (P<0.05). These data suggest that 100 mg kg(-1) and 68 mg kg(-1) of STZ can safely induce diabetes in cynomolgus monkeys aged 2-3 years, but 68 mg kg(-1) of STZ, rather than 100 mg kg(-1) of STZ, may be more appropriate for inducing diabetes in these monkeys. Furthermore, body surface area, rather than body weight, was a more reliable determinant of dosage, where 700 mg m(-2) of STZ should be the lower limit for inducing diabetes in juvenile monkeys.

Topics: Animals; Bile Acids and Salts; Blood Glucose; Body Weight; C-Peptide; Diabetes Mellitus; Disease Models, Animal; Dose-Response Relationship, Drug; Hyperglycemia; Immunohistochemistry; Islets of Langerhans; Kidney; Liver; Macaca fascicularis; Male; Streptozocin; Time Factors

Mammalian target of rapamycin (mTOR) is an important mediator for cross talk between nutritional signals and metabolic signals of insulin by downregulating insulin receptor substrate proteins. Therefore, mTOR inhibition could become a therapeutic strategy in insulin-resistant states, including insulin resistance induced by burn. We tested this hypothesis in the rat model of 30% TBSA full thickness burn, using the mTOR inhibitor rapamycin. Rapamycin (0.4 mg/kg, i.p.) was injected 2 h before euglycemic-hyperinsulinemic glucose clamps at 4 days after burn. IRS-1, phospho-serine³⁰⁷, phospho-tyrosine of IRS-1 and phospho-mTOR in muscle tissue were determined by immunoprecipitation and Western blot analysis or immunohistochemistry. Plasma TNF-α, insulin and C-peptide were determined before and after euglycemic-hyperinsulinemic glucose clamps. Our data showed that TNF-α, insulin and C-peptide significantly increased in the early stage after burn (P < 0.01). The infused rates of total 10% glucose (GIR, mg/kg min) significantly decreased at 4 days after burn. The level of IRS-1 serine³⁰⁷ phosphorylation in muscle in vivo significantly increased after burn (P < 0.01), while insulin-induced tyrosine phosphorylation of IRS-1 significantly decreased (P < 0.01). Inhibition of mTOR by rapamycin inhibited the phosphorylation of mTOR, reduced serine³⁰⁷ phosphorylation, elevated tyrosine phosphorylation and partly prevented the decrease of GIR after burn. However, TNF-α, insulin and C-peptide were not decreased by rapamycin treatment postburn. Taken together, these results indicate that the mTOR pathway is an important modulator of the signals involved in the acute regulation of insulin-stimulated glucose metabolism, and at least, partly contributes to burn-induced insulin resistance. mTOR inhibition may become a therapeutic strategy in insulin-resistant states after burn.

Topics: Animals; Anti-Bacterial Agents; Blotting, Western; Burns; C-Peptide; Disease Models, Animal; Glucose Clamp Technique; Immunohistochemistry; Insulin; Insulin Receptor Substrate Proteins; Insulin Resistance; Muscle, Skeletal; Phosphorylation; Phosphoserine; Phosphotyrosine; Rats; Rats, Sprague-Dawley; Serine; Sirolimus; TOR Serine-Threonine Kinases; Tumor Necrosis Factor-alpha

Diabetes mellitus can be treated with islet transplantation, although there is a scarcity of donors. This study investigated whether human mesenchymal stem cells (MSCs) from umbilical cord stroma could be induced to differentiate into insulin-producing cells and the effects of retro-orbital injection of human insulin-producing cells for the treatment of nonobese diabetic (NOD) mice. MSCs were isolated from human umbilical cord stroma and induced to differentiate into insulin-producing cells using differentiation medium. Differentiated cells were evaluated by immunocytochemistry, RT-PCR, and real-time PCR. C-peptide release, both spontaneous and after glucose challenge, was measured by ELISA. Insulin-producing cells were then transplanted into NOD mice. Blood glucose levels and body weights were monitored weekly. Human nuclei and C-peptide were detected in mouse livers by immunohistochemistry. Pancreatic β-cell development-related genes were expressed in the differentiated insulin-producing cells. Differentiated cells' C-peptide release in vitro increased after glucose challenge. Further, in vivo glucose tolerance tests showed that blood sugar levels decreased after the cells' transplantation into NOD mice. After transplantation, insulin-producing cells containing human C-peptide and human nuclei were located in the liver. Thus, we demonstrated that differentiated insulin-producing cells from human umbilical cord stromal MSCs transplanted into NOD mice could alleviate hyperglycemia in diabetic mice.

Topics: Animals; Blood Glucose; C-Peptide; Cell Differentiation; Cell Nucleus; Cells, Cultured; Diabetes Mellitus, Type 1; Disease Models, Animal; Glucose; Humans; Insulin; Insulin-Secreting Cells; Male; Mesenchymal Stem Cells; Mice; Mice, Inbred NOD; Stromal Cells; Umbilical Cord

Pancreatic beta cells produce and release insulin, which decreases the blood glucose level. Endoplasmic reticulum stress caused pancreatic beta cell dysfunction and death in acute necrotizing pancreatitis (ANP). The 150kD oxygen-regulated protein (ORP150) took part in the process of endoplasmic reticulum stress. This study investigated the effect of ORP150 on appearance and function of pancreatic beta cells in ANP. Acute necrotizing pancreatitis relied on retrograde infusion of 5% sodium taurocholate into the bile-pancreatic duct. The severity of ANP was estimated by serum amylase, secretory phospholipase A(2,) and pancreatic histopathology. The changes in appearance and function of pancreatic beta cells were detected by light and electron microscopy and the levels of serum glucose, insulin, and C-peptide. ORP150 expression was studied using western blot and immunohistochemisty assay. The expression of ORP150 mainly appeared on pancreatic beta cells and decreased gradually during the pathogenesis of ANP. The results of light and electron microscopy indicated pancreatic beta cell dysfunction and death, concomitant with elevation of serum glucose, insulin, and C-peptide in ANP. These results imply a probable role of ORP150 in the changes in appearance and function of pancreatic beta cells following acute necrotizing pancreatitis, through the pathway of endoplasmic reticulum stress.

Topics: Amylases; Analysis of Variance; Animals; Blood Glucose; Blotting, Western; C-Peptide; Disease Models, Animal; Endoplasmic Reticulum; HSP70 Heat-Shock Proteins; Immunohistochemistry; Insulin; Insulin-Secreting Cells; Male; Microscopy, Electron, Transmission; Pancreatitis, Acute Necrotizing; Phospholipases A2, Secretory; Proteins; Rats; Rats, Wistar; Severity of Illness Index; Taurocholic Acid; Time Factors

The atypical antipsychotics (AAPs) have been associated with increased risk of type-2 diabetes. Evidence suggests direct, drug-related effects independent of weight gain and although mechanisms underlying this phenomenon are unclear, it has been suggested that the heterogeneous receptor binding profile of the AAPs may influence receptors implicated in glucose metabolism. This study aimed to clarify weight gain-independent mechanisms of AAP-induced changes in insulin secretion by deconstructing their binding profile with representative antagonists. Healthy rats were pretreated with a single subcutaneous dose of darifenacin 6 mg/kg (n=10), a selective M(3) muscarinic antagonist; ketanserin 2mg/kg (n=10), a 5HT(2A) antagonist; raclopride 0.3mg/kg (n=11) a selective D(2)/D(3) antagonist; terfenadine 20mg/kg (n=9) a selective H(1) antagonist; or, vehicle (n=11). Hyperglycemic clamps were employed following injection, providing an index of secretory capacity of pancreatic β-cells. Acute treatment with darifenacin and ketanserin significantly decreased insulin response to glucose challenge as compared to controls, which was confirmed in the darifenacin group by reduced C-peptide levels. Treatment with raclopride resulted in an increased insulin response and a strong tendency to increased C-peptide levels. H(1) blockade did not result in effects on insulin or C-peptide. Results suggest that the effects of antipsychotics on glucose dysregulation may be related to direct inhibitory effects of muscarinic (M(3)) and serotonergic (5HT(2)) antagonism on insulin secretion. Based on the expression of D(2)-like receptors in β-cells, which mediate inhibition of insulin secretion, we propose that prolonged D(2) blockade with antipsychotics may predispose to depletion of insulin stores and an eventual defect in pancreatic compensation.

Topics: Animals; Antipsychotic Agents; Blood Glucose; C-Peptide; Disease Models, Animal; Glucose; Hyperglycemia; Insulin; Insulin Resistance; Male; Protein Binding; Radioimmunoassay; Random Allocation; Rats; Rats, Sprague-Dawley; Receptor, Muscarinic M3; Receptor, Serotonin, 5-HT2A; Receptors, Dopamine D2; Receptors, Histamine

Topics: Aluminum Hydroxide; Animals; Biomedical Research; C-Peptide; Diabetes Mellitus, Type 1; Disease Models, Animal; Glutamate Decarboxylase; Humans; Immunotherapy

In preparation for islet transplantation, diabetes was induced using streptozotocin (STZ) in non-human primates ranging from juveniles to adults with diverse body types: we studied the process with respect to the diabetic state and emergence of adverse events (AEs) and their severity, and identified risk factors for clinical and laboratory AEs. Pharmaceutical-grade STZ was given based on body surface area (BSA) (1050-1250 mg/m(2), equivalent to 80-108 mg/kg) or on body weight (BW) (100 mg/kg) to 54 cynomolgus and 24 rhesus macaques. AEs were related to risk factors, i.e. obesity parameters, BW and BSA, age and STZ dose in mg/m(2). Clinical AEs during the first days after infusion prompted euthanasia of three animals. Except for those three animals, diabetes was successfully induced as shown by circulating C-peptide levels, the intravenous glucose tolerance test and/or arginine stimulation test. C-peptide after infusion weakly correlated (P = 0.048) with STZ dose in mg/m(2). Grade ≥3 nephrotoxicity or hepatotoxicity (serum markers >3× baseline or >5 × baseline, respectively) occurred in about 10% of cases and were generally mild and reversible. Grade ≥2 clinical AEs occurred in seven of 78 animals, reversed in four cases and significantly correlated with obesity parameters. Taking girth-to-height ratio (GHtR) as an indicator of obesity, with threshold value 0.92-0.95, the positive predictive value of obesity for AEs was 92% and the specificity 94%. We conclude that diabetes is successfully induced in non-obese animals using a 100 mg/kg pharmaceutical grade STZ dose. Obesity is a significant risk factor, and animals with a higher than normal GHtR should preferably receive a lower dose. The incidence of relevant clinical or laboratory AEs is low. Careful monitoring and supportive medical intervention can result in recovery of AEs.

Topics: Animals; Body Surface Area; Body Weight; C-Peptide; Diabetes Mellitus, Experimental; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Glucose Tolerance Test; Macaca fascicularis; Macaca mulatta; Male; Obesity; Risk Factors; Streptozocin

There remains a paucity of therapeutic approaches to completely treat diabetes mellitus. This study was designed to develop a dispersed islet cell-based tissue engineering approach to engineer functional neo-islet tissues in the absence of traditional bioabsorbable scaffold matrices.. Specialized coated plastic dishes were prepared by covalently immobilizing a temperature-responsive polymer, poly(N-isopropylacrylamide), onto the plastic followed by coating with laminin-5. Dispersed rat islet cells were plated on the laminin-5-poly(N-isopropylacrylamide) dishes. After 2 days of culturing, islet cells were harvested as a uniformly connected tissue sheet by lowering the culture temperature from 37°C to 20°C for 30 min. Two harvested islet cell sheets were transplanted into the subcutaneous space of streptozotocin-induced diabetic severe combined immunodeficiency (SCID) mice to engineer neo-islet tissues in vivo. Therapeutic effects were investigated after the tissue engineering procedures.. In all of the diabetic SCID mice transplanted with the islet sheets, serum hyperglycemia was successfully reverted to a steady normoglycemic level. The recipient SCID mice demonstrated positive for serum rat C-peptide and elevated serum insulin levels. Moreover, the islet cell sheet-transplanted SCID mice demonstrated rapid glucose clearance and return of serum glucose levels after intraperitoneal glucose tolerance test. Histological examination revealed that the transplanted islet cell sheets were structured as flat clusters of islet tissues in which an active vascular network manifested within and surrounding the newly formed tissues.. This study describes a new proof-of-concept therapeutic approach to engineer functional neo-islet tissues for the treatment of type 1 diabetes mellitus.

Topics: Animals; Blood Glucose; C-Peptide; Cells, Cultured; Diabetes Mellitus, Experimental; Disease Models, Animal; Insulin; Islets of Langerhans; Islets of Langerhans Transplantation; Male; Mice; Mice, SCID; Rats; Rats, Inbred Lew; Streptozocin; Tissue Engineering; Tissue Scaffolds; Treatment Outcome

Recent studies reported that bone marrow cavity offers a widely distributed and well-vascularized microenvironment which is a considerable implantation site for bioartificial pancreas (BAP). In this study, the in vivo performance of BAPs in bone marrow was further demonstrated in a spontaneous diabetes animal. Mouse insulinoma cells encapsulating in agarose gel were enclosed in a calcium phosphate cement chamber to create a BAP. Ten BAPs were implanted into the femur bone marrow cavity of a diabetic feline. The preprandial blood glucose level, 2 h glucose curve, serum C-peptide level and physiological conditions of the recipient were recorded perioperatively. Results showed that the cat still suffered from hyperglycemia postoperatively. However, the physiological conditions of feline were improved with an increase of serum C-peptide level. The peak point of 2 h glucose curve decreased from 400 to 165-290 mg/dl. The efficiency of exogenous insulin extended from 2 to 10-14 h postoperatively which reveals that the implanted BAPs had partial function. This case report revealed that BAPs implanted in the bone marrow cavity for the spontaneous diabetic is effective. The implanted BAPs provided therapeutic benefit despite sustained hyperglycemia. Further study shall be considered to improve the outcomes of BAPs transplantation.

Topics: Animals; Blood Glucose; Bone Marrow; C-Peptide; Cats; Cell Line, Tumor; Diabetes Mellitus, Type 1; Disease Models, Animal; Hyperglycemia; Insulin; Islets of Langerhans Transplantation; Mice; Pancreas, Artificial

The metabolic syndrome (MS) has become an epidemiological problem in Western countries. We developed a diet-induced obese rat model that mimics all the symptoms of MS in humans, but whose insulin resistance, hyperphagia and hyperleptinemia are caused by nutrition rather than genetic modifications.. Spontaneously hypertensive rats (SHR) were allowed for 12 weeks to choose between a cafeteria diet (CD, 20.3 kJ/g) and standard rat chow (11.7 kJ/g). Controls received rat chow.. Body weight (BW) exceeded control levels when SHR were fed with CD. The increase in BW was attributed to enhanced energy intake. The abundance of abdominal fat as well as the plasma levels of leptin and triglycerides increased concomitant with glucose, insulin and C-peptide. This prediabetic condition was further confirmed by a markedly increased insulin response following glucose challenge and by impaired glucose utilization after insulin tolerance tests.. Increases in food intake and BW despite hyperleptinemia indicate leptin resistance following CD feeding. CD-fed SHR feature leptin and insulin resistance, hypertension and obesity, thus mimicking the situation of MS patients. As such, our model is more suitable than the genetically modified rat models used to study human MS.

Topics: Abdominal Fat; Animals; Biomarkers; Blood Glucose; Blood Pressure; Body Weight; C-Peptide; Diet; Disease Models, Animal; Energy Intake; Heart Rate; Hyperphagia; Insulin; Insulin Resistance; Leptin; Male; Metabolic Syndrome; Obesity; Rats; Rats, Inbred SHR; Rats, Sprague-Dawley; Triglycerides

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

Bone marrow mesenchymal stem cells (BMSCs) have been reported to possess low immunogenicity and cause immunosuppression of recipients when allografted. They can differentiate into insulin-producing cells and may be a valuable source for islet formation. However, the extremely low differentiating rate of adult BMSCs toward insulin-producing cells and the insufficient insulin secretion of the differentiated BMSCs in vitro prevent their clinical use in diabetes treatment. Little is known about the potential of cell replacement therapy with human BMSCs. Previously, we isolated and identified human first-trimester fetal BMSCs (hfBMSCs). Under a novel four-step induction procedure established in this study, the hfBMSCs effectively differentiated into functional pancreatic islet-like cell clusters that contained 62 ± 14% insulin-producing cells, expressed a broad gene profile related to pancreatic islet β-cell development, and released high levels of insulin (2.245 ± 0.222 pmol/100 clusters per 30 min) and C-peptide (2.200 ± 0.468 pmol/100 clusters per 30 min) in response to 25 mmol/L glucose stimulus in vitro. The pancreatic islet-like cell clusters normalized the blood glucose level of diabetic model mice for at least 9 weeks when xenografted; blood glucose levels in these mice rose abnormally again when the grafts were removed. Examination of the grafts indicated that the transplanted cells survived in recipients and produced human insulin and C-peptide in situ. These results demonstrate that hfBMSCs derived from a human first-trimester abortus can differentiate into pancreatic islet-like cell clusters following an established four-step induction. The insulin-producing clusters present advantages in cell replacement therapy of type 1 diabetic model mice.

Topics: Animals; Bone Marrow Cells; C-Peptide; Cell Aggregation; Cell Differentiation; Diabetes Mellitus, Experimental; Disease Models, Animal; Female; Fetus; Fluorescent Antibody Technique; Humans; Insulin; Insulin Secretion; Intracellular Space; Islets of Langerhans; Islets of Langerhans Transplantation; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Mice; Pregnancy; Pregnancy Trimester, First; Proinsulin; Reverse Transcriptase Polymerase Chain Reaction; Transplantation, Heterologous

Blueberries may lower relative risk for cancers of the gastrointestinal tract. Previous work indicated an inhibitory effect of consumed blueberry (BB) on formation of aberrant crypt foci (ACF) in colons of male Fisher F344 rats (inbred strain). However, effects of BB on colon tumors and in both genders are unknown.. We examined efficacy of BB in inhibition of azoxymethane (AOM)-induced colon ACF and intestine tumors in male and female Sprague-Dawley rats (outbred strain). Pregnant rats were fed a diet with or without 10% BB powder; progeny were weaned to the same diet as their dam and received AOM as young adults.. Male and female rats on control diet had similar numbers of ACF at 6 weeks after AOM administration. BB increased (P < 0.05) ACF numbers within the distal colon of female but not male rats. There was a significant (P < 0.05) diet by gender interaction with respect to total colon ACF number. Colon and duodenum tumor incidences were less in females than males at 17 weeks after AOM. BB tended (0.1 > P > 0.05) to reduce overall gastrointestinal tract tumor incidence in males, however, tumor incidence in females was unaffected (P > 0.1) by BB. There was a tendency (0.1 > P > 0.05) for fewer adenocarcinomas (relative to total of adenomatous polyps plus adenocarcinomas) in colons of female than male tumor-bearing rats; in small intestine, this gender difference was significant (P < 0.05). BB favored (P < 0.05) fewer adenocarcinomas and more adenomatous polyps (as a proportion of total tumor number) in female rat small intestine.. Results did not indicate robust cancer-preventive effects of BB. Blueberry influenced ACF occurrence in distal colon and tumor progression in duodenum, in gender-specific fashion. Data indicate the potential for slowing tumor progression (adenomatous polyp to adenocarcinoma) by BB.

Topics: Adenocarcinoma; Adenomatous Polyps; Animals; Azoxymethane; Blueberry Plants; C-Peptide; Colonic Neoplasms; Disease Models, Animal; Disease Progression; Duodenal Neoplasms; Female; Incidence; Male; Nutrition Therapy; Rats; Rats, Sprague-Dawley

Some atypical antipsychotics have been linked to an increased propensity for weight gain and metabolic disturbances, including type II diabetes. The objective of this study was to investigate an animal model to help understand the mechanisms underlying this phenomenon. Female, Sprague-Dawley rats were treated with olanzapine (2.0 or 7.5 mg/kg, via osmotic mini-pump) for 4 weeks, followed by the hyperinsulinemic/euglycemic and hyperglycemic clamp procedures to assess insulin sensitivity and secretion in vivo. Changes in body weight, visceral fat, food intake and locomotor activity were also assessed. Hepatic glucose production (R(A)) was increased in the hyperinsulinemic/euglycemic clamp for both treatment groups compared to control rats, while the high-dose olanzapine group had decreased peripheral glucose utilization (R(D)). No changes in insulin secretion were detected in the hyperglycemic clamp. Olanzapine did not change body weight or food intake, but did result in significant accumulation of visceral fat and decreases in locomotor activity. Like others, we found that a rodent model for antipsychotic-related weight gain per se is not tenable. However, chronic treatment with olanzapine was found to confer both hepatic and peripheral insulin resistance independent of weight gain, indicating a direct effect on glucose dysregulation.

Topics: Animals; Antipsychotic Agents; Benzodiazepines; Blood Glucose; Body Weight; C-Peptide; Diabetes Mellitus, Experimental; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Hyperinsulinism; Insulin Resistance; Locomotion; Olanzapine; Rats; Rats, Sprague-Dawley

The newer atypical antipsychotics, as a class, have been associated with an increased risk of weight gain and metabolic abnormalities. The mechanisms underlying this phenomenon are currently unclear, but there are data to suggest the possibility of an immediate (as opposed to chronic) effect of these drugs. The aim of the present study was to assess the acute effects of olanzapine on specific measures of insulin sensitivity and secretion. Healthy animals were tested in either the hyperinsulinemic-euglycemic or the hyperglycemic clamp. After reaching steady state in the hyperinsulinemic-euglycemic clamp, rats were injected with olanzapine (3 mg/kg sc) and monitored for an additional 130 minutes. In the hyperglycemic clamp, olanzapine was injected approximately 90 minutes before receiving a glucose bolus, and hyperglycemia was maintained via exogenous glucose infusion for an additional 90 minutes. Insulin and C-peptide levels were monitored throughout this clamp.Acute administration of olanzapine significantly lowered the glucose infusion rate due to an increase in hepatic glucose production and a decrease in glucose utilization. Olanzapine pretreatment induced hyperglycemia and markedly decreased plasma insulin and C-peptide in response to the glucose challenge. These findings indicate that olanzapine can directly induce metabolic changes that occur rapidly and well in advance of the changes that might be anticipated as a result of its weight-gain liability. We present novel findings highlighting an olanzapine-induced deficit in beta-cell functioning.

Topics: Animals; Antipsychotic Agents; Benzodiazepines; C-Peptide; Disease Models, Animal; Glucose; Glucose Clamp Technique; Hyperglycemia; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Male; Olanzapine; Rats; Rats, Sprague-Dawley; Time Factors

To quantitate insulin sensitivity in lean and obese nondiabetic baboons and examine the underlying cellular/molecular mechanisms responsible for impaired insulin action to characterize a baboon model of insulin resistance.. Twenty baboons received a hyperinsulinemic-euglycemic clamp with skeletal muscle and visceral adipose tissue biopsies at baseline and at 30 and 120 min after insulin. Genes and protein expression of key molecules involved in the insulin signaling cascade (insulin receptor, insulin receptor substrate-1, p85, phosphatidylinositol 3-kinase, Akt, and AS160) were sequenced, and insulin-mediated changes were analyzed.. Overall, baboons show a wide range of insulin sensitivity (6.2 +/- 4.8 mg x kg(-1) x min(-1)), and there is a strong inverse correlation between indexes of adiposity and insulin sensitivity (r = -0.946, P < 0.001 for % body fat; r = -0.72, P < 0.001 for waist circumference). The genes and protein sequences analyzed were found to have approximately 98% identity to those of man. Insulin-mediated changes in key signaling molecules were impaired both in muscle and adipose tissue in obese insulin-resistant compared with lean insulin-sensitive baboons.. The obese baboon is a pertinent nonhuman primate model to examine the underlying cellular/molecular mechanisms responsible for insulin resistance and eventual development of type 2 diabetes.

Topics: Animals; Biopsy; Blood Glucose; C-Peptide; Cloning, Molecular; Disease Models, Animal; Female; Glucose Clamp Technique; Hyperinsulinism; Insulin; Insulin-Secreting Cells; Male; Muscle, Skeletal; Obesity; Papio; Thinness

Insulin connecting peptide (c-peptide) aids the folding of proinsulin and has been considered to have little biological activity. Recently, c-peptide has been shown to improve diabetic neuropathy and nephropathy as well as vascular inflammation. In vitro studies have reported that c-peptide may activate peroxisome proliferator-activated receptor-gamma, a nuclear transcription factor that plays a regulatory role in inflammation. This study was designed to investigate the biological effects of c-peptide during endotoxemia.. Prospective, randomized laboratory investigation that used an established murine model of endotoxic shock.. University hospital laboratory.. Mice were subjected to endotoxic shock by intraperitoneal administration of Escherichia coli lipopolysaccharide.. Mice received vehicle or c-peptide (70-140 nmol/kg) intraperitoneally at 3 hrs and 6 hrs after lipopolysaccharide. Mortality was monitored for 96 hrs. In a separate experiment, mice were killed at 4, 7, and 18 hrs after lipopolysaccharide administration. Lungs and plasma were collected for biochemical assays.. In vehicle-treated mice, endotoxic shock resulted in lung injury and was associated with a 41% survival rate and elevation in plasma tumor necrosis factor-alpha, macrophage inflammatory protein-1alpha, monocyte chemoattractant protein-1, and keratinocyte-derived chemokine levels. Lung nuclear levels of phosphorylated extracellular signal-regulated kinases 1 and 2 were significantly increased in vehicle-treated mice. On the other hand, lung nuclear expression and DNA binding of proliferator-activated receptor-gamma were decreased in comparison to control animals. Treatment with c-peptide (140 nmol/kg) improved survival rate (68%) and reduced plasma levels of tumor necrosis factor-alpha, macrophage inflammatory protein-1alpha, and monocyte chemoattractant protein-1, but it did not exert hypoglycemic effects. Treatment with c-peptide also up-regulated lung nuclear expression and DNA binding of proliferator-activated receptor-gamma and reduced phosphorylation of extracellular signal-regulated kinases 1 and 2 in comparison to vehicle-treated mice.. Our data show that c-peptide has beneficial effects in endotoxic shock, and this therapeutic effect is associated with activation of proliferator-activated receptor-gamma.

Topics: Animals; Blood Glucose; C-Peptide; Chemokine CCL2; Chemokine CCL4; Chemokines; Disease Models, Animal; Endotoxemia; Escherichia coli; Extracellular Signal-Regulated MAP Kinases; Lipopolysaccharides; Lung; Macrophage Inflammatory Proteins; Male; Mice; PPAR gamma; Random Allocation; Survival Rate; Tumor Necrosis Factor-alpha

'Fulminant diabetes' has been recognized as a super-acute onset and non-autoimmune type 1 diabetes. To evaluate autoimmunity against pancreatic beta cell in fulminant diabetes, ELISPOT assay was applied to the peripheral blood of these patients. In our ELISPOT system, GAD65-reactive and insulin B9-23-reactive IFN-gamma spots were detected in 46.3 and 26.0% of autoantibody-positive type 1 diabetes. Also, in fulminant type 1 diabetic patients, IFN-gamma spots in response to GAD65 and insulin B9-23 peptide were detected in 69.2 and 25.0%, respectively. These results suggest that anti-beta cell autoimmunity contributes to develop fulminant type 1 diabetes. Fulminant type 1 diabetes is known to have IDDM-resistant HLA DR2 with similar frequency of non-T1D subjects. In a mouse model, when islet-reactive CD8 cells are transferred to young NOD mice, the recipients develop overt diabetes within 1 week with massive insulitis. In (NOD x Balb/c) F1 mice, which hold idd-resistant genes, transfer of islet-reactive CD8 cells induced diabetes to 60% F1 recipients within 1 week with the later disappearance of insulitis. This mouse model shows very similar feathers to fulminant type 1 diabetes; idd-resistant HLA and no insulitis. These results implicated that once anti-islet immunity is optimally activated, subjects with partially resistant alleles could become overt diabetes.

Topics: Acute Disease; Animals; C-Peptide; Diabetes Mellitus, Type 1; Diabetic Ketoacidosis; Disease Models, Animal; Humans; Insulin-Secreting Cells; Mice; Mice, Inbred BALB C; Mice, Inbred NOD; T-Lymphocytes

Recent studies on the identification of stem/progenitor cells within adult mouse and human pancreatic islets have raised the possibility that autologous transplantation might be used in treating type 1 diabetes. However, it is not yet known whether such stem/progenitor cells are impaired in type 1 diabetic patients or diabetic animal models. The latter would also allow us to test the efficacy of autologous transplantation in large animal models prior to clinical applications. The present study aims to determine the existence of stem/progenitor cells in the islets of diabetic monkey models and to assess the proliferation and differentiation potential of such cells in vitro. Our results indicate that there are pancreatic progenitor cells in the adult pancreatic islets in both normal and type 1 diabetic monkeys. The isolated pancreatic progenitor cells can be greatly expanded in culture. Upon the removal of growth medium, these cells spontaneously form islet-like cell clusters, which could be further induced to secrete insulin by inductive factors. Furthermore, the secretion of insulin and C-peptide from the islet-like cell clusters responds to glucose and other stimuli, indicating that the differentiated cells not only resemble beta-cells but also possess the unique biological function of beta-cells. This study provides a foundation for further characterization of adult pancreatic progenitor cells and autologous transplantation using pancreatic progenitor cells in treating diabetic monkeys.

Topics: Animals; C-Peptide; Cell Differentiation; Cell Separation; Cells, Cultured; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 1; Disease Models, Animal; Glucose; Insulin; Insulin Secretion; Intermediate Filament Proteins; Islets of Langerhans; Macaca fascicularis; Male; Nerve Tissue Proteins; Nestin; Stem Cells

The most common complication after allogenic islet transplantation is rejection. This study was to evaluate the effect of anti-rejection of glucocorticoid-free immunosuppressive regimen on allogenic islet transplantation.. Tacrolimus (FK506) + mycophenolate mofetil (MMF) and FK506 + MMF + prednisone (Pred) were administered respectively for 2 weeks to inhibit rejection after allogenic islet transplantation in rats, which were compared with the control group. The concentrations of blood glucose, insulin and C-peptide were determined dynamically in recipients and the sites of transplantation were observed morphologically.. As compared with the control group without immunosuppressive agents, FK506 +MMF and FK506 + MMF + Pred could prolong the survival time of grafts significantly. There were many morphologically intact islets in the liver of recipients 2 months after transplantation. Group FK506 + MMF kept normal levels of blood glucose, insulin and C-peptide beyond 60 days after transplantation. In contrast, group FK506 + MMF + Pred secreted less C-peptide (P<0.05) and maintained a higher level of blood glucose concentration (P<0.01) after the operation. There was no significant difference in insulin concentrations between the two groups. The level of blood glucose beyond the first 2 weeks after drug withdrawal in group FK506 + MMF + Pred decreased obviously (P<0.05), and the secretion of insulin and C-peptide increased. These results were compared with those the first 2 weeks after transplantation and the first 2 weeks after drug withdrawal.. Both regimens of FK506 + MMF and FK506 + MMF + Pred could provide effective immunosuppression. Moreover the combined glucocorticoid-free immunosuppressive strategy of low-dose FK506 and MMF could protect islet grafts in islet transplantation without diabetogenic side-effects.

Topics: Animals; Blood Glucose; C-Peptide; Diabetes Mellitus; Disease Models, Animal; Drug Therapy, Combination; Female; Glucocorticoids; Graft Rejection; Immunosuppression Therapy; Immunosuppressive Agents; Insulin; Islets of Langerhans Transplantation; Male; Mycophenolic Acid; Prodrugs; Rats; Rats, Sprague-Dawley; Rats, Wistar; Tacrolimus; Transplantation, Homologous

Diabetic macro- and microangiopathy are associated with a high risk of vascular complications. The diabetic patient exhibits a pathological coagulation state, with an increased synthesis of coagulation factors and plasminogen activator inhibitor 1 (PAI-1) as well as an enhanced aggregation of platelets. Previous studies have shown that C-peptide can reduce leucocyte-endothelial cell interaction and improve microvascular blood flow in patients with type 1 diabetes. In the present study, we examined in vivo whether C-peptide is able to reduce platelet activation and through that microvascular thrombus formation.. In the microvessels of cremaster muscle preparations taken from normal and diabetic mice, ferric chloride-induced thrombus formation was analysed using intravital fluorescence microscopy.. I.V. administration of C-peptide in high dose (70 nmol/kg), but not in low dose (7 nmol/kg), caused a significant delay in arteriolar and venular thrombus growth in normal and diabetic mice. This effect was repressed by cremaster muscle superfusion with insulin (100 microU/ml) in diabetic animals, but particularly in normal animals. In parallel, immunohistochemistry demonstrated a higher number of PAI-1-expressing vessels in cremaster muscle tissue from control animals and from animals treated with C-peptide and insulin compared with tissue from animals with C-peptide treatment application alone.. We conclude that C-peptide possesses antithrombotic actions in vivo. A causal role of PAI-1 in this scenario needs to be further addressed. However, the reversal of C-peptide action by insulin may invalidate the use of this peptide as a treatment option to improve rheology and microcirculation in diabetic patients.

Topics: Animals; C-Peptide; Diabetes Mellitus; Disease Models, Animal; Dose-Response Relationship, Drug; Flow Cytometry; Humans; Immunohistochemistry; Insulin; Mice; Microcirculation; P-Selectin; Plasminogen Activator Inhibitor 1; Platelet Glycoprotein GPIIb-IIIa Complex; Thrombosis

Streptozotocin (STZ) has been widely used to induce diabetes in nonhuman primates, although it has been found difficult to achieve complete diabetes without serious adverse effects. We have investigated different types and dosages of STZ to find a way to safely induce complete diabetes in cynomolgus monkeys.. After adequate hydration, 10 monkeys received STZ. Five monkeys received conventional STZ (Sigma) at a dosage of 1250 mg/m ("high dose"; n = 4) or 60 mg/kg ("low dose"; n = 1; Group 1). Five monkeys received Zanosar STZ (Sicor Pharmaceuticals, Irvine, CA) at 150 mg/kg (high dose; n = 5; Group 2).. High-dose Group 1 monkeys became completely diabetic (n = 4), but a protein-losing nephropathy was observed in 3 of the 4 monkeys. The monkey that received 60 mg/kg STZ failed to become fully diabetic (C-peptide, > 1.86 ng/mL). Group 2 (high-dose Zanosar-treated) monkeys became completely diabetic but with no apparent adverse effects. A triphasic blood glucose response to STZ was documented in all the high-dose STZ-treated monkeys. Low-dose STZ failed to result in a triphasic response.. (1) High-dose Zanosar STZ induced diabetes safely in cynomolgus monkeys without adverse effects. (2) A triphasic blood glucose response suggested the complete induction of diabetes.

Topics: Animals; C-Peptide; Diabetes Mellitus, Experimental; Disease Models, Animal; Dose-Response Relationship, Drug; Glucose Tolerance Test; Infusions, Intravenous; Macaca fascicularis; Reference Values; Streptozocin

Primary diabetic encephalopathy is a recently recognized late complication of diabetes resulting in a progressive decline in cognitive faculties. In the spontaneously type 1 diabetic BB/Wor rat, we recently demonstrated that cognitive impairment was associated with hippocampal apoptotic neuronal loss. Here, we demonstrate that replacement of proinsulin C-peptide in this insulinopenic model significantly prevented spatial learning and memory deficits and hippocampal neuronal loss. C-peptide replacement prevented oxidative stress-, endoplasmic reticulum-, nerve growth factor receptor p75-, and poly(ADP-ribose) polymerase-related apoptotic activities. It partially ameliorated apoptotic stresses mediated via impaired insulin and IGF activities. These findings were associated with the prevention of increased expression of Bax and active caspase 3 and the frequency of caspase 3-positive neurons. The results show that several partially interrelated apoptotic mechanisms are involved in primary encephalopathy and suggest that impaired insulinomimetic action by C-peptide plays a prominent role in cognitive dysfunction and hippocampal apoptosis in type 1 diabetes. Although these abnormalities were not fully prevented by C-peptide replacement, the findings suggest that this regime will substantially prevent cognitive decline in the type 1 diabetic population.

Topics: Animals; Apoptosis; C-Peptide; Caspase 12; Caspases; Cognition; Cognition Disorders; Diabetes Mellitus, Type 1; Disease Models, Animal; Hippocampus; Male; Maze Learning; Polymerase Chain Reaction; Prediabetic State; Rats; Rats, Inbred BB

We tested whether chronic overstimulation by levels of hyperglycaemia commonly found in Type 2 diabetes can irreversibly desensitise beta cells and, if so, whether desensitisation relates to the reduction of insulin content and/or the number of beta cells.. We transplanted islets from Wistar-Furth rats under the kidney capsule to neonatally streptozotocinised recipients. Recipients received daily vehicle, diazoxide (100 mg/kg) or the selective activator of beta cell type K(+)-ATP channels 6-chloro -3-(1-methylcyclopropyl) amino-4 H-thienol [3,2-e]-1,2,4-thiadiazine 1,1-dioxide (NN414) (3 mg/kg) intragastrically for at least 9 weeks. Endpoint measurements were made exactly 7 days after cessation of treatment.. Blood glucose did not differ between groups (mean of total: 13.2+/-1.4 mmol/l). C-peptide levels were significantly depressed in drug- versus vehicle-treated rats 3 to 4 hours after the last gastric tubing event, but not at endpoint. Insulin responses to 27 mmol/l glucose from perifused grafts were not significant after vehicle (median increment 18 x 10(-3) microU.islet(-1).min(-1)) but were significant per se and versus vehicle in the diazoxide and NN414 groups (median 107 and 83 x 10(-3) respectively). Rising second-phase secretion was seen only in the drug-treated groups. Stimulation by 25 mmol/l KCl, together with 0.5 mmol/l 3-isobutyl-1-methylxanthine and 3.3 mmol/l glucose, was enhanced in the drug-treated groups (p<0.05 versus vehicle). Graft insulin content did not differ between groups, nor did percentage of beta cells (between 67 and 68% of endocrine cells).. Chronic overstimulation by moderate hyperglycaemia damages signalling events including those required for glucose-induced insulin secretion. This signal transduction defect occurs in the absence of any effect on islet macro-morphometry or insulin stores.

Topics: Animals; Blood Glucose; Body Weight; C-Peptide; Diabetes Mellitus, Type 2; Disease Models, Animal; Female; Insulin; Insulin Secretion; Ion Channel Gating; Islets of Langerhans Transplantation; Male; Potassium Channels; Rats; Rats, Inbred WF; Signal Transduction; Transplantation, Isogeneic

Dysfunction of the autonomic nervous system is a recognized complication of diabetes, ranging in severity from relatively minor sweating and pupillomotor abnormality to debilitating interference with cardiovascular, genitourinary, and alimentary dysfunction. Neuroaxonal dystrophy (NAD), a distinctive distal axonopathy involving terminal axons and synapses, represents the neuropathologic hallmark of diabetic sympathetic autonomic neuropathy in man and several insulinopenic experimental rodent models. Although the pathogenesis of diabetic sympathetic NAD is unknown, recent studies have suggested that loss of the neurotrophic effects of insulin and/or insulin-like growth factor-I (IGF-I) on sympathetic neurons rather than hyperglycemia per se, may be critical to its development. Therefore, in our current investigation we have compared the sympathetic neuropathology developing after 8 months of diabetes in the streptozotocin (STZ)-induced diabetic rat and BB/ Wor rat, both models of hypoinsulinemic type 1 diabetes, with the BBZDR/Wor rat, a hyperglycemic and hyperinsulinemic type 2 diabetes model. Both STZ- and BB/Wor-diabetic rats reproducibly developed NAD in nerve terminals in the prevertebral superior mesenteric sympathetic ganglia (SMG) and ileal mesenteric nerves. The BBZDR/Wor-diabetic rat, in comparison, failed to develop superior mesenteric ganglionic NAD in excess of that of age-matched controls. Similarly, NAD which developed in axons of ileal mesenteric nerves of BBZDR/Wor rats was substantially less frequent than in BB/Wor- and STZ-rats. These data, considered in the light of the results of previous experiments, argue that hyperglycemia alone is not sufficient to produce sympathetic ganglionic NAD, but rather that it may be the diabetes-induced superimposed loss of trophic support, likely of IGF-I, insulin, or C-peptide, that ultimately causes NAD.

Topics: Animals; Autonomic Nervous System Diseases; C-Peptide; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Diabetic Neuropathies; Disease Models, Animal; Ganglia, Sympathetic; Hyperglycemia; Ileum; Insulin; Insulin-Like Growth Factor I; Male; Microscopy, Electron; Neuroaxonal Dystrophies; Rats; Rats, Mutant Strains; Sympathetic Fibers, Postganglionic

We recently reported that early gene responses and expression of cytoskeletal proteins are perturbed in regenerating nerve in type 1 insulinopenic diabetes but not in type 2 hyperinsulinemic diabetes. We hypothesized that these differences were due to impaired insulin action in the former type of diabetes. To test this hypothesis, type 1 diabetic BB/Wor-rats were replaced with proinsulin C-peptide, which enhances insulin signaling without lowering blood glucose. Following sciatic nerve crush injury, early gene responses such as insulin-like growth factor, c-fos, and nerve growth factor were examined longitudinally in sciatic nerve. Neurotrophic factors, their receptors, and beta-tubulin and neurofilament expression were examined in dorsal root ganglia. C-peptide replacement significantly normalized early gene responses in injured sciatic nerve and partially corrected the expression of endogenous neurotrophic factors and their receptors, as well as neuroskeletal protein in dorsal root ganglia. These effects translated into normalization of axonal radial growth and significantly improved axonal elongation of regenerating fibers in C-peptide-replaced BB/Wor-rats. The findings in C-peptide replaced type 1 diabetic rats were similar to those previously reported in hyperinsulinemic and iso-hyperglycemic type 2 BB/Z-rats. We conclude that impaired insulin action may be more important than hyperglycemia in suppressing nerve fiber regeneration in type 1 diabetic neuropathy.

Topics: Animals; C-Peptide; Cytoskeletal Proteins; Diabetes Mellitus, Type 1; Diabetic Neuropathies; Disease Models, Animal; Immunohistochemistry; Insulin; Insulin-Like Growth Factor I; Male; Nerve Crush; Nerve Degeneration; Nerve Growth Factor; Nerve Growth Factors; Nerve Regeneration; Proto-Oncogene Proteins c-fos; Rats; Rats, Inbred BB; Receptor, IGF Type 1; Receptors, Nerve Growth Factor; Sciatic Nerve

Insulin and C-peptide exert neuroprotective effects and are deficient in Type I (insulin-dependent) diabetes mellitus but not in Type II (non-insulin-dependent) diabetes mellitus. These studies were designed to test the preventive and interventional effects of C-peptide replacement on diabetic polyneuropathy in the Type I diabetic BB/Wor rat.. Diabetic BB/Wor rats were replaced with rat C-peptide from onset of diabetes and between 5 and 8 months of diabetes. They were examined at 2 and 8 months and compared to non-C-peptide replaced BB/Wor rats, Type II diabetic (non-C-peptide deficient) BB/Z rats and non-diabetic control rats. Animals were monitored as to hyperglycaemia and nerve conduction velocity (NCV). Acute changes such as neural Na+/K+-ATPase and paranodal swelling were examined at 2 months, morphometric and teased fiber analyses were done at 8 months.. C-peptide replacement for 2 months in Type I diabetic rats prevented the acute NCV defect by 59% (p < 0.005), the neural Na+/K+-ATPase defect by 55% (p < 0.001) and acute paranodal swelling by 61% (p < 0.001). Eight months of C-peptide replacement prevented the chronic nerve conduction defect by 71% (p < 0.001) and totally prevented axoglial dysjunction (p < 0.001) and paranodal demyelination (p < 0.001). C-peptide treatment from 5 to 8 months showed a 13% (p < 0.05) improvement in NCV, a 33% (p < 0.05) improvement in axoglial dysjunction, normalization (p < 0.001) of paranodal demyelination, repair of axonal degeneration (p < 0.01), and a fourfold (p < 0.001) increase in nerve fibre regeneration.. C-peptide replacement of Type I BB/Wor-rats partially prevents acute and chronic metabolic, functional and structural changes that separate Type I diabetic polyneuropathy from its Type II counterpart suggesting that C-peptide deficiency plays a pathogenetic role in Type I diabetic polyneuropathy.

Topics: Animals; Axons; C-Peptide; Diabetes Mellitus, Type 1; Diabetic Neuropathies; Disease Models, Animal; Male; Myelin Sheath; Nerve Regeneration; Neural Conduction; Rats; Rats, Inbred BB; Time Factors

Topics: Acute Disease; Animals; C-Peptide; Chronic Disease; Diabetic Neuropathies; Disease Models, Animal; Insulin; Neural Conduction; Ranvier's Nodes; Rats; Sodium Channels

The objective of the study reported here was to induce obesity in the female Göttingen minipig to establish a model of the human metabolic syndrome. Nine- to ten-month-old female Göttingen minipigs received a high-fat high-energy (HFE) diet or a low-fat, low-energy (LFE) diet. The energy contents derived from fat were 55 and 13 %, respectively. After 5 weeks, animals were subjected to dual energy x-ray absorptiometry (DEXA) scanning, intravenous glucose tolerance testing (IVGTT), and 6-h growth hormone profile recording. After treatment, mean body weight of pigs of the LFE group was 21.0 +/- 0.4 kg, and was 26.8 +/- 0.2 kg in pigs of the HFE group (P < 0.0001). The DEXA scanning indicated that the fat content of the LFE group was 10.0 +/- 1.2 % versus 15.2 +/- 0.7 % in the HFE group (P < 0.003). Triglycerides concentration was significantly (P < 0.05) increased in pigs of the HFE group (0.24 +/- 0.03 mM), compared with that in pigs of the LFE group (0.13 +/- 0.04 mM). Preprandial plasma glucose and insulin concentrations were not affected, but insulin area under the curve during IVGTT was significantly high in the obese animals. Growth hormone (GH) secretion was low in both groups of pigs. The obese minipig shares some of the metabolic impairments seen in obese humans, and may thus serve as a model of the metabolic syndrome.

Topics: Absorptiometry, Photon; Animals; Area Under Curve; Blood Glucose; C-Peptide; Diet, Fat-Restricted; Dietary Fats; Disease Models, Animal; Fasting; Female; Fructosamine; Glucose Tolerance Test; Growth Hormone; Humans; Hypercholesterolemia; Hypertriglyceridemia; Insulin; Insulin Secretion; Insulin-Like Growth Factor I; Lipids; Metabolic Syndrome; Obesity; Pituitary Gland, Anterior; Species Specificity; Swine, Miniature

The pig is useful as a model for human physiology and pathophysiology and could be an important supplement to the many available rodent models of diabetes mellitus. Due to their small size, Göttingen minipigs are especially suitable for long-term studies. The aim of the study reported here was to establish reference values for a range of glucose and lipid homeostasis parameters of interest that could be used to identify possible diabetes-prone male Göttingen minipig individuals, families, or age groups. Plasma samples from nonfed animals were analyzed for glucose, leptin, fructosamine, insulin, C-peptide, triglyceride, free fatty acids, and total cholesterol values. Breeding family had significant effects only on plasma triglyceride concentrations (P < 0.001). Plasma concentrations of glucose (P = 0.012), fructosamine (P < 0.001) and triglycerides (P < 0.001) increased significantly with age, whereas total cholesterol concentration decreased significantly (P = 0.001) with age. Age did not influence other parameters. In conclusion, glycemia and insulinemia increased with age and body weight, possibly indicating a small deterioration in insulin sensitivity with age. It is, therefore, hypothesized that older, compared to younger animals may be more useful in the development of a model of type-2 diabetes mellitus. Furthermore, on the basis of decrease in cholesterol concentration with age, animals fed ad libitum with possibly a high calorie diet might be even more useful in the development of a type-2 diabetes mellitus model.

Topics: Aging; Animals; Blood Glucose; Body Weight; Breeding; C-Peptide; Diabetes Mellitus, Type 2; Disease Models, Animal; Fructosamine; Homeostasis; Humans; Insulin; Lipids; Male; Reference Values; Swine; Swine, Miniature; Triglycerides

Insulin-dependent diabetes mellitus (IDDM) is the second most prevalent chronic illness of children. Investigation of the treatment of IDDM is hindered by the lack of a reproducible and easily maintained non-human primate model of this disorder.. We induced IDDM in 11 juvenile cynomolgus monkeys after a single (150 mg/kg) intravenous injection of streptozotocin (STZ). All diabetic monkeys were treated with insulin twice daily, based on a sliding scale. Subcutaneous vascular access ports were surgically placed in each monkey to facilitate serial blood sampling and drug administration. Allogeneic pancreatic islet cells from unrelated donors were subsequently transplanted into the mesenteric circulation of all STZ-treated monkeys.. Mild, transient nausea and vomiting occurred in all animals after STZ injection; however, no additional signs of toxicity occurred. Within 36 hr, all monkeys required twice daily administration of exogenous insulin to maintain a non-ketotic state. Serum C-peptide levels decreased from >1.2 ng/ml before STZ, to between 0.0 and 0.9 ng/ml after STZ, confirming islet cell destruction. Animals were maintained in an insulin-dependent state for up to 147 days without any observable clinical complications. Subcutaneous vascular access port patency was maintained up to 136 days with a single incidence of local infection. Islet cell transplantation resulted in normoglycemia within 24 hr. Serum C-peptide levels increased (range: 2-8 ng/ml) for 6 - 8 days in immune competent animals, and for 39-98 days after transplant in immunosuppressed monkeys.. IDDM can be consistently induced and safely treated in juvenile cynomolgus monkeys. Chronic vascular access can be maintained with minimal supervision and complications. This model is appropriate for studies investigating potential treatments for IDDM including islet cell transplantation.

Topics: Animals; C-Peptide; Catheterization; Child, Preschool; Chronic Disease; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 1; Disease Models, Animal; Femoral Vein; Glucose Tolerance Test; Humans; Immunosuppressive Agents; Insulin; Insulin Infusion Systems; Islets of Langerhans Transplantation; Kidney; Macaca fascicularis; Pancreas; Streptozocin; Vascular Patency

Many obese middle-aged rhesus monkeys (Macaca mulatta) spontaneously develop noninsulin dependent diabetes mellitus (NIDDM). Basal hyperinsulinemia and increased stimulated plasma insulin levels are associated with this obesity and precede the onset of overt diabetes. The present studies sought to determine the relative contributions of enhanced insulin secretion and of reduced insulin clearance to this early obesity-associated hyperinsulinemia. Direct simultaneous measurement of portal and jugular vein insulin levels in two normal monkeys showed a constant rate of hepatic insulin extraction of 56+/-3% over the range of peripheral insulin levels from 351+/-113 to 625+/-118 pmol/L. In 33 additional monkeys ranging from normal to diabetic, basal C-peptide levels were examined as an indicator of beta-cell secretion and the molar ratio of plasma C-peptide to insulin (C/I ratio) under basal steady state conditions calculated as an index of hepatic insulin extraction. Well in advance of overt diabetes, there was a progressive decline of 67% in the apparent hepatic insulin extraction rate in association with increased obesity and plasma insulin levels. Basal insulin levels and hepatic insulin extraction returned toward normal in monkeys with impaired glucose tolerance and in those with overt diabetes. We conclude that reduced insulin disposal, probably due to reduced hepatic extraction of insulin, in addition to increased beta-cell activity, contributes to the development of basal hyperinsulinemia in obese rhesus monkeys progressing toward NIDDM. In addition, in overt diabetes, normal hepatic insulin extraction in the presence of limited beta-cell secretion may exacerbate the hypoinsulinemic state.

Topics: Adipose Tissue; Animals; Blood Glucose; Body Weight; C-Peptide; Diabetes Mellitus, Type 2; Disease Models, Animal; Female; Glucose Tolerance Test; Hyperinsulinism; Insulin; Insulin-Secreting Cells; Jugular Veins; Liver; Macaca mulatta; Male; Metabolic Diseases; Obesity; Portal Vein; Receptor, Insulin; Time Factors

Chronic in utero hyperinsulinemia in the fetal rhesus monkey produces a number of changes in the fetus that are similar to those found in the human infant of the diabetic mother, including macrosomia, selective organomegaly, and altered insulin secretion during the neonatal period. The chronically hyperinsulinemic fetal rhesus model has been used to test the hypothesis that the effects of chronic hyperinsulinemia persist beyond the neonatal period into later life and may, in part, be responsible for the increased prevalence of impaired glucose tolerance or diabetes found in the human infant of the diabetic mother. We report that infant rhesus monkeys that had plasma insulin concentrations of approximately 10 times basal levels (2176 +/- 808 pmol compared to 172 +/- 101 pmol) exhibited reduced insulin secretion during the first 5 months of life. The integrated incremental change in plasma insulin and immunoreactive C-peptide (IRCP) concentration was significantly reduced by approximately 50% in response to i.v. glucose, arginine, and tolbutamide when given at 3, 4, and 5 months of age. The response to glucagon at 2 months of age was equivocal with a significantly reduced insulin response but without the corresponding IRCP reduction. There was no difference between groups in insulin sensitivity as measured at 6 months of age by an i.v. insulin tolerance test. The glucagon and glucose tolerance tests were repeated annually in both groups until the animals were 3 yr of age with no differences in insulin or IRCP secretion being observed. We conclude that chronic in utero euglycemic hyperinsulinemia results in impaired insulin secretion that persists beyond the neonatal period.

Topics: Animals; Animals, Newborn; Blood Glucose; Body Weight; C-Peptide; Disease Models, Animal; Female; Fetal Blood; Fetal Diseases; Fetal Macrosomia; Gestational Age; Hyperinsulinism; Insulin; Insulin Secretion; Macaca mulatta; Pregnancy; Umbilical Arteries; Umbilical Veins

Peripheral hyperinsulinaemia usually found in conventionally treated Type 1 (insulin-dependent) diabetic patients may have deleterious metabolic effects. We have used a hyperinsulinaemic model to examine intermediary metabolism in two key peripheral tissues, aorta and muscle. Nine pigs were immunized with crystalline insulin. Subsequently, they showed an insulin-binding capacity of 86.2 +/- 25.0 pmol/l and fasting total serum insulin of 3.9 +/- 3.1 nmol/l (control range 0.034-0.072 nmol/l), impaired glucose tolerance after oral glucose tolerance testing, significantly elevated levels of peripheral venous serum free insulin and C-peptide, and increased mean post-prandial free insulin/glucose ratios. The immunized pigs showed marked elevation of aorta and muscle triglycerides compared with control pigs (n = 15) but similar levels of non-esterified fatty acids. The glucose-6-phosphate-dehydrogenase, malic enzyme and 3-hydroxyacyl-CoA-dehydrogenase activities were all increased significantly (by 50%-300%) in both aorta and muscle. Phosphofructokinase was decreased in both tissues. Hexokinase was increased in muscle alone whereas pyruvate kinase was significantly decreased in aorta. Glyceraldehyde-3-phosphate dehydrogenase activity was not significantly different in aorta and muscle. Thus in insulin immunized pigs with normal beta-cell function and pronounced peripheral hyperinsulinaemia there was increased peripheral lipogenic activity. These findings have potentially important implications with regard to macrovascular disease in diabetes.

Topics: Animals; Aorta; Blood Glucose; C-Peptide; Cattle; Disease Models, Animal; Fatty Acids, Nonesterified; Female; Glucose Tolerance Test; Hyperinsulinism; Insulin; Male; Muscles; Swine; Triglycerides

Nonhuman primate models of gestational diabetes have produced fetopathies most similar to those of the human infant of the mother with gestational diabetes (IGDM). Fetal hyperglycemia, hyperinsulinemia, macrosomia, selective organomegaly, intrauterine death, and placental hyperplasia are hallmarks of the fetopathy of the IGDM. The chronic infusion of insulin into the fetus of a normal pregnant rhesus monkey results in fetal hyperinsulinemia with normal to low plasma metabolic substrate concentrations. Under these conditions, fetal hyperinsulinemia is sufficient to cause fetal growth and hormone changes observed in the human IGDM. Our studies provide evidence that the soft tissue hyperplasia in the fetal macrosomia syndromes in humans and nonhuman primates in which fetal hyperinsulinemia is observed is the direct result of that chronic in utero hyperinsulinemia.

Topics: Adipose Tissue; Amino Acids; Animals; Birth Weight; Blood Glucose; C-Peptide; Disease Models, Animal; Erythropoietin; Female; Fetal Blood; Fetal Hypoxia; Fetus; Glucagon; Hydrocortisone; Insulin; Macaca mulatta; Pregnancy; Pregnancy in Diabetics

Topics: Amniotic Fluid; Animals; Blood Circulation; C-Peptide; Disease Models, Animal; Female; Fetal Growth Retardation; Insulin; Insulin Secretion; Peptides; Placenta; Pregnancy; Rats; Uterus