transforming-growth-factor-beta and Diabetes-Mellitus

Cardiomyopathy (CDM) and related morbidity and mortality are increasing at an alarming rate, in large part because of the increase in the number of diabetes mellitus cases. The clinical consequence associated with CDM is heart failure (HF) and is considerably worse for patients with diabetes mellitus, as compared to nondiabetics. Diabetic cardiomyopathy (DCM) is characterized by structural and functional malfunctioning of the heart, which includes diastolic dysfunction followed by systolic dysfunction, myocyte hypertrophy, cardiac dysfunctional remodeling, and myocardial fibrosis. Indeed, many reports in the literature indicate that various signaling pathways, such as the AMP-activated protein kinase (AMPK), silent information regulator 1 (SIRT1), PI3K/Akt, and TGF-β/smad pathways, are involved in diabetes-related cardiomyopathy, which increases the risk of functional and structural abnormalities of the heart. Therefore, targeting these pathways augments the prevention as well as treatment of patients with DCM. Alternative pharmacotherapy, such as that using natural compounds, has been shown to have promising therapeutic effects. Thus, this article reviews the potential role of the quinazoline alkaloid, oxymatrine obtained from the Sophora flavescensin CDM associated with diabetes mellitus. Numerous studies have given a therapeutic glimpse of the role of oxymatrine in the multiple secondary complications related to diabetes, such as retinopathy, nephropathy, stroke, and cardiovascular complications via reductions in oxidative stress, inflammation, and metabolic dysregulation, which might be due to targeting signaling pathways, such as AMPK, SIRT1, PI3K/Akt, and TGF-β pathways. Thus, these pathways are considered central regulators of diabetes and its secondary complications, and targeting these pathways with oxymatrine might provide a therapeutic tool for the diagnosis and treatment of diabetes-associated cardiomyopathy.

Topics: Alkaloids; AMP-Activated Protein Kinases; Diabetes Mellitus; Diabetic Cardiomyopathies; Humans; Insulin Resistance; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Signal Transduction; Sirtuin 1; Transforming Growth Factor beta

Diabetes is one of the most comprehensive metabolic disorders and is spread across the globe. The data from IDF Diabetes Atlas and National Diabetes Statistics mentions that the number of patients with diabetes is increasing at an exponential rate which is challenging the current therapeutics used for the management of diabetes. However, current therapies used for the treatment may provide symptomatic relief but lack in preventing the progression of the disease and thereby limiting the treatment of diabetes-associated complications. A thorough review and analysis were conducted using various databases including EMBASE, MEDLINE, and Google Scholar to extract the available information on challenges faced by current therapies which have triggered the development of novel molecules or drugs. From the analysis, it was analyzed that transforming growth factor βs (TGF-βs) have been shown to exhibit pleiotropic activity and are responsible for maintaining homeostasis and its overexpression is convoluted in the pathogenesis of various disorders. Therefore, developing drugs that block TGF-β signaling may provide therapeutic benefits. This extensive review concluded that drugs targeting TGF-β signaling pathway and its subsequent blockade have shown promising results and hold the potential to become drugs of choice in the management of diabetes and associated complications.

Topics: Diabetes Complications; Diabetes Mellitus; Homeostasis; Humans; Transforming Growth Factor beta

Beta (β) cell dysfunction or loss is the common pathological feature in all types of diabetes mellitus (diabetes). Resolving the underlying mechanism may facilitate the treatment of diabetes by preserving the β cell population and function. It is known that TGF-β signaling plays diverse roles in β cell development, function, proliferation, apoptosis, and dedifferentiation. Inhibition of TGF-β signaling expands β cell lineage in the development. However, deletion of

Topics: Animals; Cell Proliferation; Diabetes Mellitus; Insulin-Secreting Cells; Insulins; Mice; Transforming Growth Factor beta

Diabetic nephropathy (DN), one of the most common and intractable microvascular complications of diabetes, is the main cause of terminal renal disease globally. MicroRNA-21 (miR-21) is a kind of miRNA early identified in human circulation and tissues. Mounting studies have demonstrated that miR-21 plays an important role in the development and progression of DN. This collaborative review aimed to present a first attempt to capture the current evidence on the relationship between miR-21 and DN. After a systematic search, 29 relevant studies were included for comprehensively and thoroughly reviewing. All these eligible studies reported that miR-21 was up-regulated in DN, whether in serum or renal tissues of human or animal models. MiR-21 exhibited its pathogenic roles in DN by forming a complex network with targeted genes (e.g. MMP-9, Smad7, TIMP3, Cdk6, FOXO1, IMP3, and MMP2) and the signaling cascades (e.g. Akt/TORC1 signaling axis, TGF-β/NF-κB signaling pathways, TGF-β/SMAD pathway, CADM1/STAT3 signaling, and AGE-RAGE regulatory cascade), which resulted in epithelial-to-mesenchymal transition, extracellular matrix deposition, cytoskeletal remodeling, inflammation, and fibrosis. This review highlights that miR-21 is a pivotal pathogenic factor in the development of DN. It may serve as an attractive potential diagnostic, prognostic, and predictive biomarker for DN in clinical practice after further confirmation of the clinicopathological features and molecular mechanisms of miR-21-mediated DN.

Topics: Animals; Cell Adhesion Molecule-1; Diabetes Mellitus; Diabetic Nephropathies; Fibrosis; Humans; MicroRNAs; Transforming Growth Factor beta; Virulence Factors

Diabetic kidney disease (DKD) is one of the most common complications of diabetes, and its prevalence is still growing rapidly. However, the efficient therapies for this kidney disease are still limited. The pathogenesis of DKD involves glucotoxicity, lipotoxicity, inflammation, oxidative stress, and renal fibrosis. Glucotoxicity and lipotoxicity can cause oxidative stress, which can lead to inflammation and aggravate renal fibrosis. In this review, we have focused on in vitro and in vivo experiments to investigate the mechanistic pathways by which natural compounds exert their effects against the progression of DKD. The accumulated and collected data revealed that some natural compounds could regulate inflammation, oxidative stress, renal fibrosis, and activate autophagy, thereby protecting the kidney. The main pathways targeted by these reviewed compounds include the Nrf2 signaling pathway, NF-κB signaling pathway, TGF-β signaling pathway, NLRP3 inflammasome, autophagy, glycolipid metabolism and ER stress. This review presented an updated overview of the potential benefits of these natural compounds for the prevention and treatment of DKD progression, aimed to provide new potential therapeutic lead compounds and references for the innovative drug development and clinical treatment of DKD.

Topics: Diabetes Mellitus; Diabetic Nephropathies; Fibrosis; Glycolipids; Humans; Inflammasomes; Inflammation; Kidney; NF-E2-Related Factor 2; NF-kappa B; NLR Family, Pyrin Domain-Containing 3 Protein; Transforming Growth Factor beta

Despite considerable investigation in diabetic nephropathy (DN) pathogenesis and possible treatments, current therapies still do not provide competent prevention from disease progression to end-stage renal disease (ESRD) in most patients. Therefore, investigating exact molecular mechanisms and important mediators underlying DN may help design better therapeutic approaches for proper treatment. MicroRNAs (MiRNAs) are a class of small non-coding RNAs that play a crucial role in post-transcriptional regulation of many gene expression within the cells and present an excellent opportunity for new therapeutic approaches because their profile is often changed during many diseases, including DN. This review discusses the most important signaling pathways involved in DN and changes in miRNAs profile in each signaling pathway. We also suggest possible approaches for miRNA derived interventions for designing better treatment of DN.

Topics: Animals; Diabetes Mellitus; Diabetic Nephropathies; Gene Targeting; Humans; MicroRNAs; Signal Transduction; Transforming Growth Factor beta; Treatment Outcome

Diabetes mellitus (DM), is the most common metabolic disease and is characterized by sustained hyperglycemia. Accumulating evidences supports a strong association between DM and numerous lung diseases including chronic obstructive pulmonary disease (COPD), fibrosis, and lung cancer (LC). The global incidence of DM-associated lung disorders is rising and several ongoing studies, including clinical trials, aim to elucidate the molecular mechanisms linking DM with lung disorders, in particular LC. Several potential mechanisms, including hyperglycemia, hyperinsulinemia, glycation, inflammation, and hypoxia, are cited as plausible links between DM and LC. In addition, studies also propose a connection between the use of anti-diabetic medications and reduction in the incidence of LC. However, the exact cause for DM associated lung diseases especially LC is not clear and is an area under intense investigation. Herein, we review the biological links reported between DM and lung disorders with an emphasis on LC. Furthermore, we report common signaling pathways (eg: TGF-β, IL-6, HIF-1, PDGF) and miRNAs that are dysregulated in DM and LC and serve as molecular targets for therapy. Finally, we propose a nanomedicine based approach for delivering therapeutics (eg: IL-24 plasmid DNA, HuR siRNA) to disrupt signaling pathways common to DM and LC and thus potentially treat DM-associated LC. Finally, we conclude that the effective modulation of commonly regulated signaling pathways would help design novel therapeutic protocols for treating DM patients diagnosed with LC.

Topics: Antineoplastic Agents; Diabetes Mellitus; Humans; Hypoglycemic Agents; Hypoxia-Inducible Factor 1, alpha Subunit; Interleukin-6; Lung Diseases; Lung Neoplasms; MicroRNAs; Nanomedicine; Platelet-Derived Growth Factor; Signal Transduction; Transforming Growth Factor beta

Pancreatic cancer is a common malignant digestive disease. Epidemiological and clinical studies have demonstrated that pancreatic cancer is closely related to diabetes mellitus. Diabetic patients are more likely to develop pancreatic cancer, which is linked with poor outcomes. Pancreatic cancer is complicated with abnormal blood sugar and insulin resistance and promotes the development of diabetes mellitus. Understanding the molecular mechanisms linking diabetes mellitus and pancreatic cancer is essential for the treatment of diabetes cancer patients. The transforming growth factor-β (TGF-β) signaling pathway is deregulated in cancer and has a dual role in different stages of cancer as a suppressor or a promoter. More important, The TGF-β signaling pathway is also another important reason for diabetic complications. This review summarizes the relationship between diabetes and pancreatic cancer, in particular, focusing on the role of the TGF-β signaling pathway. It is possible to find drugs like metformin that can prevent and treat pancreatic cancer by targeting the TGF-β signaling pathway.

Topics: Diabetes Mellitus; Humans; Insulin Resistance; Pancreatic Neoplasms; Receptors, Transforming Growth Factor beta; Signal Transduction; Transforming Growth Factor beta

Both type 1 and type 2 diabetes are associated with cardiac fibrosis that may reduce myocardial compliance, contribute to the pathogenesis of heart failure, and trigger arrhythmic events. Diabetes-associated fibrosis is mediated by activated cardiac fibroblasts, but may also involve fibrogenic actions of macrophages, cardiomyocytes and vascular cells. The molecular basis responsible for cardiac fibrosis in diabetes remains poorly understood. Hyperglycemia directly activates a fibrogenic program, leading to accumulation of advanced glycation end-products (AGEs) that crosslink extracellular matrix proteins, and transduce fibrogenic signals through reactive oxygen species generation, or through activation of Receptor for AGEs (RAGE)-mediated pathways. Pro-inflammatory cytokines and chemokines may recruit fibrogenic leukocyte subsets in the cardiac interstitium. Activation of transforming growth factor-β/Smad signaling may activate fibroblasts inducing deposition of structural extracellular matrix proteins and matricellular macromolecules. Adipokines, endothelin-1 and the renin-angiotensin-aldosterone system have also been implicated in the diabetic myocardium. This manuscript reviews our current understanding of the cellular effectors and molecular pathways that mediate fibrosis in diabetes. Based on the pathophysiologic mechanism, we propose therapeutic interventions that may attenuate the diabetes-associated fibrotic response and discuss the challenges that may hamper clinical translation.

Topics: Animals; Diabetes Mellitus; Diabetic Cardiomyopathies; Endomyocardial Fibrosis; Endothelial Cells; Extracellular Matrix Proteins; Gene Expression Regulation; Glycation End Products, Advanced; Humans; Hypoglycemic Agents; Macrophages; Myocytes, Cardiac; Receptor for Advanced Glycation End Products; Renin-Angiotensin System; Signal Transduction; Smad Proteins; Transforming Growth Factor beta

There are a variety of pathophysiologic conditions that are known to induce skeletal muscle atrophy. However, muscle wasting can occur through multiple distinct signaling pathways with differential sensitivity between selective skeletal muscle fiber subtypes. This review summarizes some of the underlying molecular mechanisms responsible for fiber-specific muscle mass regulation.. Peroxisome proliferator-activated receptor gamma coactivator 1-alpha protects slow-twitch oxidative fibers from denervation/immobilization (disuse)-induced muscle atrophies. Nutrient-related muscle atrophies, such as those induced by cancer cachexia, sepsis, chronic heart failure, or diabetes, are largely restricted to fast-twitch glycolytic fibers, of which the underlying mechanism is usually related to abnormality of protein degradation, including proteasomal and lysosomal pathways. In contrast, nuclear factor kappaB activation apparently serves a dual function by inducing both fast-twitch fiber atrophy and slow-twitch fiber degeneration.. Fast-twitch glycolytic fibers are more vulnerable than slow-twitch oxidative fibers under a variety of atrophic conditions related to signaling transduction of Forkhead box O family, autophagy inhibition, transforming growth factor beta family, and nuclear factor-kappaB. The resistance of oxidative fibers may result from the protection of peroxisome proliferator-activated receptor gamma coactivator 1-alpha.

Topics: Animals; Cachexia; Chronic Disease; Diabetes Mellitus; Disease Models, Animal; Forkhead Box Protein O1; Forkhead Transcription Factors; Glycolysis; Heart Diseases; Humans; Muscle Fibers, Fast-Twitch; Muscle Fibers, Slow-Twitch; Muscular Atrophy; Muscular Diseases; NF-kappa B; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; Sepsis; Signal Transduction; Transcription Factors; Transforming Growth Factor beta

Atherosclerosis is accelerated in the setting of diabetes, but the factors driving this phenomenon remain elusive. Hyperglycemia leads to elevated levels of transforming growth factor (TGF)-β and TGF-β has been implicated as a factor in atherosclerosis. Given the established association between hyperglycemia and elevated TGF-β, it is plausible that elevated TGF-β levels in diabetes play a pathogenic role in the development of accelerated atherosclerosis. TGF-β is a potent regulator of extracellular matrix synthesis, including many actions on proteoglycan synthesis that lead to increased binding to low-density lipoprotein and therefore potentially increased lipid retention in the vessel wall and accelerated atherosclerosis. TGF-β signals through the canonical TGF-β receptor I-mediated phosphorylation of Smad transcription factors and TGF-β signaling is also known to involve, positively and negatively, interactions with the mitogen-activated protein kinase pathways. The focus of the present review is on the effects of TGF-β on proteoglycan synthesis in vascular smooth muscle and particularly the signaling pathways through which TGF-β exerts its effects, because those pathways may be therapeutic targets for the prevention of pathological modifications in the proteoglycan component of the vessel wall in the vascular diseases of diabetes.

Topics: Animals; Atherosclerosis; Diabetes Mellitus; Extracellular Matrix; Humans; Lipoproteins, LDL; Mice; Mitogen-Activated Protein Kinases; Muscle, Smooth, Vascular; Proteoglycans; Receptors, Transforming Growth Factor beta; Smad Proteins; Transforming Growth Factor beta

Diabetic nephropathy is one of the most common diseases leading to fibrosis and end-stage renal disease (ESRD) world wide. Under normal conditions, a delicate equilibrium exists between synthesis, composition, and removal of extracellular matrix (ECM). If this is disturbed, ECM accumulation and fibrosis may result. The fragile balance between synthesis and removal of ECM is crucial for the prognosis of glomerular as well as interstitial pathological processes. Some features may favor ECM accumulation and progression to ESRD (dialysis and transplantation), whereas other elements may favor ECM removal and resolution (recovery). Pathogenetic mechanisms and the cellular sources of ECM in the glomerular basement membrane as well as in the tubulointerstitial space are still under investigation. Among several growth factors, transforming growth factor beta1 (TGF-beta1) plays a major role. We consider the use of living animals necessary for our understanding of the complex biological processes that occur during the development of ESRD. The present review will discuss the glomerular as well as interstitial accumulation of ECM and the use of transgenic animals in studying the pathogenetic mechanisms with special emphasis on diabetic kidney disease and TGF-beta1.

Topics: Animals; Animals, Genetically Modified; Diabetes Mellitus; Diabetic Nephropathies; Disease Models, Animal; Extracellular Matrix; Humans; Transforming Growth Factor beta; Transforming Growth Factor beta1

Transforming growth factor beta-1 is involved in local signaling for a variety of human diseases including renal diseases, cardiac hypertrophy and fibrosis in heart failure, hepatic fibrosis, and pulmonary fibrosis. Elevated levels of circulating transforming growth factor beta-1 result in organ fibrosis in animal models. In humans smoking, hypertension, diabetes and obesity appear to result in elevated circulating levels. This paper outlines a hypothesis that elevated circulating levels of transforming growth factor beta-1 are part of the molecular link between several entities that have epidemiologic ties including hypertension, diabetes, smoking and obesity on one hand and diseases resulting in organ fibrosis on the other including renal disease and cardiac fibrosis and hypertrophy in heart failure. Additionally, it is suggested that elevated levels are not simply a marker of a similar mechanism of disease production but that elevated levels of circulating transforming growth factor beta-1 lead to disease production and to the synergy of risk factors seen in production of human fibrotic diseases.

Topics: Animals; Diabetes Mellitus; Fibrosis; Humans; Hypertension; Models, Animal; Obesity; Signal Transduction; Smoking; Transforming Growth Factor beta; Transforming Growth Factor beta1

Modification of proteins by nonenzymatic glycation is one of the underlying factors contributory to the development of complications of diabetes. In general, the nature of this structural modification falls into two broad categories: nonenzymatic glycation per se, which refers to the attachment of free carbohydrate to proteins in the Amadori construct, and Advanced Glycation Endproducts (AGE), which refers to a heterogeneous group of carbohydrate-modified products generated from the Amadori adduct by oxidation, polymerization, and other spontaneous reactions. This review will focus on the role of nonenzymatically glycated proteins, and in particular glycated serum albumin, in the pathogenesis of diabetic complications, and on pharmacologic approaches to mitigate their deleterious effects. Potential intervention strategies to lessen the influence of AGE-modified proteins, as well as of other contributory abnormalities, are discussed elsewhere in this volume.

Topics: Animals; Antibodies, Monoclonal; Carbohydrate Metabolism; Diabetes Mellitus; Diabetic Nephropathies; Extracellular Matrix Proteins; Forecasting; Glycated Serum Albumin; Glycation End Products, Advanced; Glycosylation; Humans; Models, Biological; Protein Binding; Protein Kinase C; Serum Albumin; Transforming Growth Factor beta

In this chapter, we summarize our studies on plasminogen activator inhibitor 1 (PAI-1), tissue factor, and transforming growth factor beta (TGF-beta) expression in obesity, using genetically obese mice as a model. These studies emphasize the key role played by the adipocyte, a cell whose numbers, size, and metabolic activity are grossly altered in obesity/NIDDM. They also implicate multiple cytokines, hormones, and growth factors in the abnormal expression of these and perhaps other hemostatic genes by adipocytes in obesity/NIDDM. These studies demonstrate that tumor necrosis factor alpha (TNF-alpha) plays a central role in the expression of hemostatic genes in this disorder.

Topics: Adipocytes; Animals; Diabetes Mellitus; Diabetes Mellitus, Type 2; Gene Expression Regulation; Hemostasis; Humans; Mice; Mice, Obese; Obesity; Plasminogen Activator Inhibitor 1; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

Topics: Animals; Biomarkers; Diabetes Mellitus; Diabetes Mellitus, Experimental; Diabetic Nephropathies; Diabetic Retinopathy; Enzyme-Linked Immunosorbent Assay; Glycation End Products, Advanced; Humans; Transforming Growth Factor beta

Plasminogen activator inhibitor-1 is elevated in obesity and may be a risk factor for obesity/NIDDM related cardiovascular disease. In spite of this, little is known about the tissue and cellular origin of elevated PAI-1 in obesity or of the mediators and molecular mechanisms that regulate it. We have begun to systematically address these issues using genetically obese (ob/ob, db/db) mice. Plasma PAI-1 levels were 5-fold higher in obese mice compared to their lean counterparts. Subsequent RT-PCR and in situ hybridization studies suggest that the increased plasma PAI-1 originates primarily from the adipocyte in response to chronically elevated levels of tumor necrosis factor-alpha (TNF-alpha), insulin, and transforming growth factor-beta (TGF-beta). Thus, the signals and mechanisms that lead to elevated plasma PAI-1 observed in obesity are complex, and appear to involve interactions between multiple mediators and the adipose tissue itself.

Topics: Animals; Diabetes Mellitus; Diabetes Mellitus, Type 2; Humans; Mice; Mice, Obese; Models, Genetic; Obesity; Plasminogen Activator Inhibitor 1; Risk Factors; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

Chronic hyperglycemia may cause growth factor alterations that are likely to participate in tissue remodeling typical for diabetic late complications. However, few details of such events are known. The ocular vitreous fluid allows studies of growth factor levels in human eyes (after vitrectomy). The vitreous is highly inert and protected by the blood-retina barrier and thus probably reflects growth factor production by the normal retina. Vitreous from patients with proliferative diabetic retinopathy (PDR) was compared with vitreous obtained from patients with nonproliferative eye disease and with vitreous from patients without diabetes but with marked neovascular proliferations due to ischemia. This design permits us to distinguish diabetes-related from non-diabetes-related alterations. Insulin-like growth factor I (IGF-I), IGF-II, IGF binding protein 2 (IGFBP-2), and IGFBP-3 were elevated 3- to 13-fold in nondiabetic retinal ischemia and 1.5- to 3-fold in PDR, indicating that the changes were not restricted to diabetes. These changes may partially be explained by leakage of serum into the vitreous, since IGFs and IGFBPs are 20- to 50-fold higher in serum than in vitreous, and vitreous protein content was 1.5-fold elevated in PDR subjects and 5-fold in ischemia patients compared with control subjects. TGF-beta is a proposed antiangiogenic factor in the eye. TGF-beta2 was the predominant subtype in vitreous, and its total amount was not altered in PDR patients. More importantly, the active fraction of TGF-beta was decreased by 30 and 70% in PDR and nondiabetic retinal ischemia patients, respectively. Since plasmin may control TGF-beta activation, the serum protein alpha2-antiplasmin was measured and found to be significantly elevated to 150 and 250% of control values in PDR and ischemia patients, respectively. Thus, influx of serum proteins due to microvascular disturbances and hypoxia is proposed as a possible cause for vitreous alterations of IGF-I and of active TGF-beta. These changes seem to occur late in the sequence of events leading to PDR and are not specific for diabetes, but they were also observed in other diseases characterized by retinal hypoxia.

Topics: alpha-2-Antiplasmin; Blood-Retinal Barrier; Diabetes Mellitus; Diabetic Retinopathy; Growth Substances; Humans; Insulin-Like Growth Factor Binding Protein 2; Insulin-Like Growth Factor Binding Protein 3; Insulin-Like Growth Factor I; Insulin-Like Growth Factor II; Neovascularization, Pathologic; Transforming Growth Factor beta; Vitreous Body

Lipoprotein(a) constitutes a macromolecular complex in human plasma that combines structural features from the blood clotting and the lipoprotein systems. Aside from the discovery of lipoprotein(a) [Lp(a)] as a potential independent risk factor for premature cardiovascular disease its physiological role and activity remains obscure. Since the site of catabolism has not yet been fully characterized, there is intensive search for factors which influence plasma Lp(a) levels. Several clinical conditions and metabolic states have been identified to be added to the disorders of the lipid metabolism itself that modulate Lp(a) plasma levels. Diseases of the kidney and their accompanying factors (proteinuria and nephrotic syndrome) as well as end-stage renal disease and their treatment modalities (hemodialysis, peritoneal dialysis, and kidney transplantation) have all been found to increase Lp(a) plasma levels substantially. Fluctuations in Lp(a) also seem to occur in states of hormonal changes, such as in diabetes mellitus, after estrogen treatment, and during pregnancy. Recently a plausible mechanism for the atherogenic activity of Lp(a) has been ascribed to the inhibiting effect of Lp(a) on plasminogen activation, thus decreasing plasmin formation which in turn reduces the activation of transforming growth factor beta, a potent inhibitor of smooth muscle cell proliferation. Lp(a) exerts its pathological effect at plasma levels in the range of 20-30 mg/dl. Therefore, it seems mandatory to quantitate Lp(a) levels in patients who are at risk of developing progressive atherosclerotic disease to identify those with high levels of this unique atherogenic lipoprotein.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Arteriosclerosis; Cell Division; Chromosomes, Human, Pair 6; Diabetes Mellitus; Disease Susceptibility; Estrogens; Female; Humans; Hyperlipidemias; Kidney Diseases; Kringles; Lipoprotein(a); Male; Muscle, Smooth, Vascular; Phenotype; Plasminogen; Pregnancy; Risk; Transforming Growth Factor beta

Pressure ulcers (PU) are wounds located mainly on bone surfaces where the tissue under pressure suffers ischemia leading to cellular lesion and necrosis , its causes and the healing process depend on several factors. The aim of this study was evaluating the gene expression of inflammatory/reparative factors: IL6, TNF, VEGF, and TGF, which take part in the tissue healing process under effects of low-level laser therapy (LLLT). In order to perform lesion area analysis, PUs were photographed and computer analyzed. Biochemical analysis was performed sa.mpling ulcer border tissue obtained through biopsy before and after laser therapy and quantitative real-time PCR (qRT-PCR) analysis. The study comprised eight individuals, mean age sixty-two years old, and sacroiliac and calcaneous PU, classified as degree III and IV according to the National Pressure Ulcer Advisory Panel (NPUAP). PUs were irradiated with low-level laser (InGaAIP, 100 mW, 660 nm), energy density 2 J/cm

Topics: Biomarkers; Diabetes Mellitus; Female; Gene Expression Regulation; Granulation Tissue; Humans; Inflammation; Interleukin-6; Low-Level Light Therapy; Male; Middle Aged; Pressure Ulcer; Real-Time Polymerase Chain Reaction; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha; Vascular Endothelial Growth Factor A; Wound Healing

Proteinuria is a significant independent determinant of the progression of chronic renal diseases. It induces an increased synthesis of angiotensin II, endothelin and profibrogenic growth factors, such as transforming growth factor-beta (TGF-beta), by mesangial and tubular cells. The antiproteinuric effect of angiotensin-converting enzyme inhibitors (ACEIs) in diabetic and non-diabetic nephropathies predicts long-term renoprotection afforded by these drugs. Angiotensin II receptor antagonists are renoprotective in patients with type 2 diabetes, but studies about their effect in non-diabetic proteinuric nephropathies are very scarce.. We randomly assigned 97 patients with non-diabetic nephropathies and proteinuria >1.5 g/24 h to treatment with losartan (50 mg daily) or amlodipine (5 mg daily) for 20 weeks. Doses of the study medications were titrated to achieve a target blood pressure <140/90 mmHg in both groups. Primary outcome was the decrease in the level of 24 h proteinuria. Secondary outcomes were changes in the plasma and urinary levels of TGF-beta.. The baseline characteristics in both groups were similar. Proteinuria decreased by 32.4% (95% confidence interval -38.4 to -21.8%) after 4 weeks of treatment and by 50.4% (-58.9 to -40.2%) after 20 weeks in the losartan group, whereas no significant proteinuria changes were observed in the amlodipine group (P < 0.001). There was no significant correlation between the level of baseline proteinuria and the proteinuria decrease induced by losartan. Both losartan and amlodipine induced a similar and significant blood pressure reduction. Target blood pressure was achieved with the initial dose of study medication (50 mg daily) in 76% of losartan group patients and in 68% of the amlodipine group patients (5 mg daily). Urinary TGF-beta significantly decreased with losartan (-22.4% of the baseline values after 20 weeks of treatment), whereas it tended to increase with amlodipine (between-group difference P < 0.05). A significant correlation between proteinuria decrease and urinary TGF-beta reduction was found in the losartan group (r = 0.41, P < 0.005). Serum creatinine and serum potassium remained stable during the study in both groups.. Losartan induced a drastic decrease in proteinuria accompanied by a reduction in urinary excretion of TGF-beta in patients with non-diabetic proteinuric renal diseases.

Topics: Adult; Amlodipine; Angiotensin Receptor Antagonists; Antihypertensive Agents; Calcium Channel Blockers; Diabetes Mellitus; Double-Blind Method; Female; Humans; Kidney Diseases; Losartan; Male; Middle Aged; Prospective Studies; Proteinuria; Transforming Growth Factor beta; Treatment Outcome

Chronic non healing wounds in diabetic patients still impose a major problem in modern medicine. Especially additional peripheral vascular disease complicates treatment success in these patients. Thus, we analyzed the effects of 11,12 epoxyeicosatrienoic acid (EET) in a combined model of hyperglycemia and ischemia in mice. Hyperglycemia was induced by Streptozotozin 2 weeks prior to wounding. 3 days before wound creation 2 of the 3 suppling vessels of the moue ear were cautherized for ischemia. Either 11,12 EET or solvent for control was applied. Wound closure as well as TNF-α, TGF-β, SDF-1α, VEGF, CD31, and Ki67 were measured. The wounds closed on day 14.4 ± 0.4 standard deviation (SD). 11,12 EET treatment enhanced healing to 9.8 ± 0.6 SD. TNF-α level was augmented on day 9 compared to control and receded on day 18. TGF-β seemed to be elevated all days observed after 11,12 EET treatment. SDF-1α was enhanced on day 6 and 9 by 11,12 EET, and VEGF on day 6 and 18 as well as CD13 on day 3, 6, and 18. 11,12 EET did not alter Ki67. 11,12 EET are able to rescue deteriorated wound healing in a combined model of hyperglycamia and ischemia by resolution of inflammation, augmentation of neovascularization and increasing expression of TGF-β as well as SDF-1α.

Topics: Animals; Chemokine CXCL12; Diabetes Mellitus; Hyperglycemia; Ischemia; Ki-67 Antigen; Mice; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha; Vascular Endothelial Growth Factor A; Wound Healing

Diabetic kidney disease is an important microvascular complication of diabetes and the leading cause of end-stage renal disease. Its pathological characteristics mainly include epithelial mesenchymal transition(EMT) in glomerulus, podocyte apoptosis and autophagy, and damage of glomerular filtration barrier. Transforming growth factor-β(TGF-β)/Smad signaling pathway is specifically regulated by a variety of mechanisms, and is a classic pathway involved in physiological activities such as apoptosis, proliferation and differentiation. At present, many studies have found that TGF-β/Smad signaling pathway plays a key role in the pathogenesis of diabetic kidney disease. Traditional Chinese medicine has significant advantages in the treatment of diabetic kidney disease for its multi-component, multi-target and multi-pathway characteristics, and some traditional Chinese medicine extracts, traditional Chinese medicines and traditional Chinese medicine compound prescription improve the renal injury of diabetic kidney disease by regulating TGF-β/Smad signaling pathway. This study clarified the mechanism of TGF-β/Smad signaling pathway in diabetic kidney disease by expounding the relationship between the key targets of the pathway and diabetic kidney disease, and summarized the research progress of traditional Chinese medicine in the treatment of diabetic kidney disease by interfering with TGF-β/Smad signaling pathway in recent years, to provide reference for drug research and clinical treatment of diabetic kidney disease in the future.

Topics: Diabetes Mellitus; Diabetic Nephropathies; Epithelial-Mesenchymal Transition; Humans; Kidney; Medicine, Chinese Traditional; Signal Transduction; Smad Proteins; Transforming Growth Factor beta; Transforming Growth Factor beta1

Podocytes, the key component of the glomerular filtration barrier (GFB), are gradually lost during the progression of diabetic kidney disease (DKD), severely compromising kidney functionality. The molecular mechanisms regulating the survival of podocytes in DKD are incompletely understood. Here, we show that membrane-associated guanylate kinase inverted 2 (MAGI2) is specifically expressed in renal podocytes, and promotes podocyte survival in DKD. We found that MAGI2 expression was downregulated in podocytes cultured with high-glucose in vitro, and in kidneys of db/db mice as well as DKD patients. Conversely, we found enforced expression of MAGI2 via AAV transduction protected podocytes from apoptosis, with concomitant improvement of renal functions. Mechanistically, we found that MAGI2 deficiency induced by high glucose levels activates TGF-β signaling to decrease the expression of anti-apoptotic proteins. These results indicate that MAGI2 protects podocytes from cell death, and can be harnessed therapeutically to improve renal function in diabetic kidney disease.

Topics: Adaptor Proteins, Signal Transducing; Animals; Apoptosis; Communication; Diabetes Mellitus; Diabetic Nephropathies; Glucose; Guanylate Kinases; Humans; Mice; Podocytes; Transforming Growth Factor beta

Monocytes/macrophages play a prominent role in cutaneous wound healing. Persistent inflammation in diabetic wounds is associated with the inability of monocytic cells to switch from a phagocytic M1 (classically activated) to an anti-inflammatory, pro-regenerative M2 (alternatively activated) phenotype and as consequence, the proliferative phase of healing does not commence. A targeted cell therapy approach could potentially restore the pathological wound microenvironment through paracrine signalling to enable healing. This study investigated whether in vitro pre-treatment of monocytic (J774.1 A) cells - using a combination of endotoxin-induced immune tolerance (Pam3CSK4) and M2 polarization (IL-4) - could make these cells impervious to the pathological wound microenvironment and enhance the release of anti-inflammatory cytokines/growth factors. The effect of Pam3CSK4-induced tolerance and IL-4-associated polarization was assessed independently and in combination, on the expression of intracellular (flow cytometry) and secreted (ELISA) cytokines (TNF-ɑ, IL-6, IL-10, TGF-β) with and without re-stimulation to define the optimal pre-treatment conditions. Successive pre-treatment approach consisting of endotoxin tolerance followed by IL-4 priming, dampened TNF-ɑ release and induced intracellular TGF-β production upon re-stimulation. To mimic a chronic wound microenvironment, the J774A.1 monocytes were differentiated into macrophages using GM-CSF prior to pre-treatment (optimal condition) and subsequently exposed to diabetic wound fluid. The data demonstrated that in the presence of wound fluid, the successive pre-treatment, promoted M2 polarization (CD206) of monocytic cells and significantly dampened the intracellular production of both pro-inflammatory (TNF-ɑ, IL-6) and anti-inflammatory (IL-10, TGF-β) cytokines.

Topics: Anti-Inflammatory Agents; Cytokines; Diabetes Mellitus; Humans; Interleukin-10; Interleukin-4; Interleukin-6; Macrophages; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

Diabetic foot ulceration is a major diabetic complication with unmet needs. We investigated the efficacy of epidermal stem cells and epidermal stem cells-derived exosomes (ESCs-Exo) in improving impaired diabetic wound healing and their mechanisms of action. In vitro experiments showed that ESCs-Exo enhanced the proliferation and migration of diabetic fibroblasts and macrophages and promoted alternative or M2 macrophage polarization. In wounds of db/db mice, treatment with both epidermal stem cells and ESCs-Exo, when compared with fibroblast exosomes and PBS control, accelerated wound healing by decreasing inflammation, augmenting wound cell proliferation, stimulating angiogenesis, and inducing M2 macrophage polarization. Multiplex protein quantification of wound lysates revealed TGFβ signaling influenced by ESCs-Exo. High-throughput sequencing of small RNAs contained in the ESCs-Exo showed higher proportions of microRNAs than those contained in fibroblast exosomes. In silico functional analysis showed that the ESCs-Exo microRNAs‒target genes were primarily involved in homeostatic processes and cell differentiation and highlighted regulatory control of phosphatidylinositol-3 kinase/protein kinase B and TGFβ signaling pathways. This was also validated in vitro. Collectively, our results indicate that epidermal stem cells and ESCs-Exo are equally effective in promoting impaired diabetic wound healing and that ESCs-Exo treatment may be a promising and technically advantageous alternative to stem cell therapies.

Topics: Animals; Diabetes Mellitus; Diabetic Foot; Exosomes; Mice; MicroRNAs; Stem Cells; Transforming Growth Factor beta; Wound Healing

Diabetes mellitus (DM) is a chronic metabolic disorder characterized by inappropriate hyperglycemia, which causes endothelial dysfunction and peripheral neuropathy, ultimately leading to multiple complications. One prevalent complication is diabetic erectile dysfunction (ED), which is more severe and more resistant to treatment than nondiabetic ED. The serum glycoprotein leucine-rich ɑ-2-glycoprotein 1 (LRG1) is a modulator of TGF-β-mediated angiogenesis and has been proposed as a biomarker for a variety of diseases, including DM. Here, we found that the adhesion GPCR latrophilin-2 (LPHN2) is a TGF-β-independent receptor of LRG1. By interacting with LPHN2, LRG1 promotes both angiogenic and neurotrophic processes in mouse tissue explants under hyperglycemic conditions. Preclinical studies in a diabetic ED mouse model showed that LRG1 administration into the penile tissue, which exhibits significantly increased LPHN2 expression, fully restores erectile function by rescuing vascular and neurological abnormalities. Further investigations revealed that PI3K, AKT, and NF-κB p65 constitute the key intracellular signaling pathway of the LRG1/LPHN2 axis, providing important mechanistic insights into LRG1-mediated angiogenesis and nerve regeneration in DM. Our findings suggest that LRG1 can be a potential new therapeutic option for treating aberrant peripheral blood vessels and neuropathy associated with diabetic complications, such as diabetic ED.

Topics: Animals; Diabetes Mellitus; Erectile Dysfunction; Glycoproteins; Humans; Male; Mice; Neovascularization, Pathologic; Receptors, Peptide; Receptors, Transforming Growth Factor beta; Transforming Growth Factor beta

Regenerating defective bone in patients with diabetes mellitus remains a significant challenge due to high blood glucose level and oxidative stress. Here we aim to tackle this issue by means of a drug- and cell-free scaffolding approach. We found the nanoceria decorated on various types of scaffolds (fibrous or 3D-printed one; named nCe-scaffold) could render a therapeutic surface that can recapitulate the microenvironment: modulating oxidative stress while offering a nanotopological cue to regenerating cells. Mesenchymal stem cells (MSCs) recognized the nanoscale (tens of nm) topology of nCe-scaffolds, presenting highly upregulated curvature-sensing membrane protein, integrin set, and adhesion-related molecules. Osteogenic differentiation and mineralization were further significantly enhanced by the nCe-scaffolds. Of note, the stimulated osteogenic potential was identified to be through integrin-mediated TGF-β co-signaling activation. Such MSC-regulatory effects were proven in vivo by the accelerated bone formation in rat calvarium defect model. The nCe-scaffolds further exhibited profound enzymatic and catalytic potential, leading to effectively scavenging reactive oxygen species in vivo. When implanted in diabetic calvarium defect, nCe-scaffolds significantly enhanced early bone regeneration. We consider the currently-exploited nCe-scaffolds can be a promising drug- and cell-free therapeutic means to treat defective tissues like bone in diabetic conditions.

Topics: Animals; Bone Regeneration; Cell Differentiation; Cerium; Diabetes Mellitus; Integrins; Mesenchymal Stem Cells; Osteogenesis; Oxidative Stress; Rats; Tissue Scaffolds; Transforming Growth Factor beta

Diabetic wounds are one of the most important issues in diabetic patients. It seems that Juglans regia L. leaf with antioxidant and anti-inflammatory potentials can be profitable for healing of diabetic wounds. The aim of present study was to investigate the topical administration of Juglans regia L. leaf extract in diabetic wound healing.. Seventy-five diabetic male rats were randomly divided into 5 groups (n = 15), including: untreated (Control) group, Eucerin group, 2% Juglans regia L. ointment (JRL 2%) group, 5% Juglans regia L. ointment (JRL 5%) group, and Phenytoin group as a reference drug. Sampling was performed at days 7, 14, and 21 after surgery. Evaluation tests included stereology, immunohistochemistry, molecular, and biomechanical.. Our results showed that the wound closure rate, volumes of newly formed of epidermis and dermis, density of fibroblasts and blood vessels, collagen deposition, density of proliferation cells, expression levels of TGF-β and VEGF genes, and biomechanical characteristics were significantly higher in extract groups compared to control and eucerin groups, however, these changes were considerable in the JRL 5% group (P < 0.05). This is while that the density of neutrophils and expression levels of TNF-α and IL-1β genes in the extract groups, especially in the JRL 5% group, were significantly reduced compared to control and eucerin groups (P < 0.05).. Topical administration of Juglans regia L. leaf extract, especially in 5% concentration, considerably accelerates diabetic wound healing.

Topics: Administration, Topical; Animals; Antioxidants; Collagen; Diabetes Mellitus; Juglans; Male; Ointments; Phenytoin; Plant Extracts; Rats; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha; Vascular Endothelial Growth Factor A; Wound Healing

Diabetic kidney disease (DKD) is the most common cause of end-stage renal disease (ESRD) worldwide. Currently, there is no effective treatment to completely prevent DKD progression to ESRD. Renal fibrosis and inflammation are the major pathological features of DKD, being pursued as potential therapeutic targets for DKD.. Inflammation and renal fibrosis are involved in the pathogenesis of DKD. Anti-inflammatory drugs have been developed to combat DKD but without efficacy demonstrated. Thus, we have focused on the mechanisms of TGF-β-induced renal fibrosis in DKD, as well as discussing the important molecules influencing the TGF-β signaling pathway and their potential development into new pharmacotherapies, rather than targeting the ligand TGF-β and/or its receptors, such options include Smads, microRNAs, histone deacetylases, connective tissue growth factor, bone morphogenetic protein 7, hepatocyte growth factor, and cell division autoantigen 1.. TGF-β is a critical driver of renal fibrosis in DKD. Molecules that modulate TGF-β signaling rather than TGF-β itself are potentially superior targets to safely combat DKD. A comprehensive elucidation of the pathogenesis of DKD is important, which requires a better model system and access to clinical samples via collaboration between basic and clinical researchers.

Topics: Autoantigens; Bone Morphogenetic Protein 7; Connective Tissue Growth Factor; Diabetes Mellitus; Diabetic Nephropathies; Fibrosis; Hepatocyte Growth Factor; Histone Deacetylases; Humans; Inflammation; Kidney; Kidney Failure, Chronic; Ligands; MicroRNAs; Transforming Growth Factor beta; Transforming Growth Factors

Diabetes affects select organs such as the eyes, kidney, heart, and brain. Our recent studies show that diabetes also enhances adipogenesis in the bone marrow and reduces the number of marrow-resident vascular regenerative stem cells. In the current study, we have performed a detailed spatio-temporal examination to identify the early changes that are induced by diabetes in the bone marrow. Here we show that short-term diabetes causes structural and molecular changes in the marrow, including enhanced adipogenesis in tibiae of mice, prior to stem cell depletion. This enhanced adipogenesis was associated with suppressed transforming growth factor-beta (TGFB) signaling. Using human bone marrow-derived mesenchymal progenitor cells, we show that TGFB pathway suppresses adipogenic differentiation through TGFB-activated kinase 1 (TAK1). These findings may inform the development of novel therapeutic targets for patients with diabetes to restore regenerative stem cell function.

Topics: Animals; Bone Marrow; Diabetes Mellitus; Humans; Mesenchymal Stem Cells; Mice; Transforming Growth Factor beta; Transforming Growth Factors

Probiotics are nonpathogenic bacterial strains that exert beneficial effects on the host. Previous studies have shown that topical use of some strains of probiotic bacteria have good effects on the healing of cutaneous wounds. In the current study, the wound healing potentials of bacterial probiotics on diabetic cutaneous wounds were evaluated. The effects of probiotics on migration, the viability of fibroblasts, and macrophage proliferation were measured through using wound healing assay, methylthiazol tetrazolium assay, and bromodeoxyuridine, respectively. In this regard, in vivo diabetic wound healing experiments in Wistar rats following treatment with nontoxic concentrations of Lactobacillus bulgaricus and Lactobacillus plantarum were conducted. The histopathological and gene expression analyses were performed following removal of wound sites 3, 7, and 14 days postwounding. Results showed that treatment with probiotics accelerated the healing process of diabetic wounds and modulated the inflammatory cells in wound sites during a 14-day period postwounding. The altered mRNA levels of inflammatory cytokines were observed in wound sites following treatment with probiotics. The findings of the current study reveal that L. bulgaricus and L. plantarum could improve the healing of diabetic wounds via regulation of inflammation.

Topics: Animals; Cell Survival; Cells, Cultured; Diabetes Mellitus; Humans; Inflammation; Interleukin-10; Interleukin-1beta; Lactobacillus delbrueckii; Lactobacillus plantarum; Mice; Probiotics; Rats; Rats, Wistar; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha; Wound Healing

This study was designed to investigate the protective effects and mechanisms of acteoside on DKD in diabetes male db/db mice and high glucose-induced HK-2 cells. The diabetes db/db mice were divided randomly into model group, metformin group, irbesartan group, and acteoside group. We observed the natural product of acteoside exhibiting a significant effect in renal protection through analyzing of biochemical indicators and endogenous metabolites, histopathological observations, and western blotting. HK-2 cells subjected to high glucose were used in invitro experiments. The molecular mechanisms of them were investigated by RT-PCR and western blot. Acteoside prevents high glucose-induced HK-2 cells and diabetes db/db mice by inhibiting NADPH/oxidase-TGF-β/Smad signaling pathway. Acteoside regulated the disturbed metabolic pathway of lipid metabolism, glyoxylate and dicarboxylate metabolism, and arachidonic acid metabolism. We discovered the natural product of acteoside exhibiting a significant effect in renal protection. This study paved the way for further exploration of pathogenesis, early diagnosis, and development of a new therapeutic agent for DKD.

Topics: Animals; Biological Products; Cell Line; Diabetes Mellitus; Diabetic Nephropathies; Glucosides; Humans; Kidney; Male; Mice; NADP; NADPH Oxidases; Phenols; Signal Transduction; Smad Proteins; Transforming Growth Factor beta

The aim of this study was to identify differentially expressed microRNAs (miRNAs) in the vitreous of patients with proliferative diabetic retinopathy (PDR) and correlate some of them with growth factors.. Vitreous samples were collected from 5 PDR eyes and 5 control eyes, and then miRNAs were assayed with next-generation sequencing (NGS). Three differentially expressed miRNAs were validated in vitreous of another cohort using reverse transcriptase quantitative polymerase chain reaction (RT-qPCR).. Transforming growth factor β (TGF-β) and vascular endothelial growth factor (VEGF) signaling pathway were excavated out through bioinformatic analysis of deregulated miRNAs. The expression of hsa-miR-24-3p, hsa-miR-197-3p and hsa-miR-3184-3p, VEGF-A and TGF-β were confirmed to be significantly higher in the vitreous of PDR eyes than controls(P < 0.05). Furthermore, Pearson's correlation analysis showed significantly positive correlations between these elevated miRNAs and growth factors (P < 0.05).. Elevated vitreous levels of hsa-miR-24-3p, hsa-miR-197-3p, hsa-miR-3184-3p in PDR patients may play roles in pathophysiology of PDR, the target mRNAs of which significantly enriched in VEGF and TGF-β signaling pathways. Positive correlations between elevated vitreous levels of the three miRNAs and VEGF-A, TGF-β in PDR patients could provide a novel research direction for PDR.

Topics: Diabetes Mellitus; Diabetic Retinopathy; Enzyme-Linked Immunosorbent Assay; Humans; MicroRNAs; Signal Transduction; Transforming Growth Factor beta; Vascular Endothelial Growth Factor A; Vitreous Body

Diabetes mellitus can reinforce the small airway dysfunction of chronic obstructive pulmonary disease (COPD) patients. The epithelial-mesenchymal transition (EMT) that is associated with small airway remodeling is activated in the airway epithelial cells (AECs) of both COPD patients and diabetic patients. Transforming growth factor β (TGF-β) can induce EMT via the TGF-β/Smad pathway. We found that the small airway dysfunction and airflow limitations were worse in COPD patients with a history of smoking or diabetes than in simple COPD patients, and were even worse in COPD patients with both histories. Pulmonary ventilation tests in rats confirmed these findings. EMT and the TGF-β/Smad pathway were activated in the AECs of rats with COPD or diabetes, and the combination of COPD and diabetes amplified those effects, as indicated by downregulation of Zo1 and upregulation of vimentin, TGF-β and Smad4 in immunohistochemical experiments. Twenty-four-hour treatment with 25 mM glucose and/or 1% cigarette smoke extract upregulated vimentin, TGF-β, Smad2/3/4 and p-Smad2/3, but downregulated Zo1 in AECs. Suppressing the TGF-β/Smad pathway prevented EMT activation and small airway remodeling following cigarette smoke exposure and hyperglycemia. Thus, cigarette smoke and high glucose exposure induces EMT via the TGF-β/Smad pathway in AECs.

Topics: Aged; Airway Remodeling; Animals; Blood Glucose; Diabetes Mellitus; Diabetes Mellitus, Experimental; Epithelial-Mesenchymal Transition; Female; Humans; Male; Pulmonary Disease, Chronic Obstructive; Rats; Signal Transduction; Smoking; Transforming Growth Factor beta

Diabetic nephropathy (DN) is one of the notorious diabetes associated complications. Despite many therapeutic strategies available, metabolic control of DN continues to poses a challenge. In this study, the interactions of mangiferin with selected oral hypoglycemic drugs, metformin and gliclazide to effectively alleviate the symptoms of renal injury in DN are evaluated. Male Sprague Dawley rats were used as experimental model and type II diabetes was induced by administration of high fat diet and low dose streptozotocin. Oral intervention of mangiferin with metformin and gliclazide for a period of 28 days was given to diabetic rats. At the end of the treatment period, biochemical parameters, kidney function markers, anti-oxidant enzymes levels, oxidative stress mediated gene expression and histology were analysed. Significant reduction in the serum biochemical markers (glucose, urea and creatinine) were observed in the groups treated with combination drugs. Marked improvement in the combination treated groups in terms of inflammation and oxidative damage in the gene (TNFα, NFκB, TGFβ, VEGF, PKC) and protein expression (NFκB, VEGF) were noted in the kidney tissue alleviating the symptoms of DN. These results were further corroborated with histopathological results. Scientific data in the present study reveals that the combinations of mangiferin with the oral hypoglycemic drugs have been favorable in alleviating renal injury. Hence, a combination therapy to alleviate the vascular complication, diabetic nephropathy may be considered as a possible therapeutic strategy by including natural phytocompounds as an add on therapy to conventional oral hypoglycemic drugs.

Topics: Animals; Antioxidants; Diabetes Mellitus; Diabetes Mellitus, Experimental; Diabetic Nephropathies; Drug Therapy, Combination; Gliclazide; Hypoglycemic Agents; Kidney; Kidney Function Tests; Male; Metformin; NF-kappa B; Oxidative Stress; Rats; Rats, Sprague-Dawley; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha; Xanthones

To determine the associations between the levels of certain cytokines in the aqueous humor and the severity of diabetic retinopathy.. A total of 103 patients (one eye per patient) who received intravitreal injection with ranibizumab for diabetic retinopathy were enrolled and divided into 3 groups: nonproliferative diabetic retinopathy (NPDR) with macular edema group (42 eyes), proliferative diabetic retinopathy (PDR) group (40 eyes) and neovascular glaucoma due to PDR (NVG-PDR) group (21 eyes). The concentrations of interleukin (IL)-6, IL-8, IL-10, vascular endothelial growth factor (VEGF), transforming growth factor-β (TGF-β), vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), and monocyte chemoattractant protein-1 (MCP-1) in the aqueous humor were measured.. In this study, 42, 40 and 21 patients (one eye per patient) were included in the NPDR, PDR and NVG-PDR groups, respectively. The median concentrations of IL-6, IL-8, IL-10, VEGF, TGF-β, VCAM-1, ICAM-1 and MCP-1 in the groups were measured. The levels of these 8 cytokines increased with the severity of diabetic retinopathy, especially in the NVG-PDR group. Compared with those in the NPDR group, the aqueous concentrations of these 8 cytokines were higher in the PDR group and were the highest in the NVG-PDR group. There were significant differences in all cytokines among the three groups (P < 0.05). Multivariate analysis showed that in the NPDR and PDR groups, the risk of PDR associated with elevated levels of TGF-β (P = 0.0004, OR 1.11, 95% CI [1.05-1.18]) and ICAM-1 (P = 0.0408, OR 10.75, 95% CI [1.10-104.61]). In the PDR and NVG groups, the risk of NVG associated with elevated levels of IL-10 (P = 0.0486, OR 0.7040, 95% CI [0.4966, 0.9979]), VEGF (P = 0.0279, OR 0.9963, 95% CI [0.9931, 0.9996]), and VCAM-1 (P = 0.0316, OR 0.9998, 95% CI [0.9996, 0.99998]). In the three groups, the risk of developing NVG associated with elevated levels of TGF-β (P < 0.001, OR 1.04, 95% CI [1.02, 1.05]).. The levels of these eight cytokines in the aqueous humor increased with the severity of diabetic retinopathy, especially in NVG-PDR. This study suggests that TGF-β, ICAM-1, IL-10, VEGF, and VCAM-1 may play a role in the progression of diabetic retinopathy, especially TGF-β, which may plays a significant role in NVG-PDR. These cytokines potentially may be used as biomarkers to predict the progress of diabetic retinopathy, contribute to the choice of treatment options and/or monitor treatment responses.

Topics: Aqueous Humor; Chemokine CCL2; Cytokines; Diabetes Mellitus; Diabetic Retinopathy; Glaucoma, Neovascular; Humans; Intercellular Adhesion Molecule-1; Interleukin-10; Interleukin-6; Interleukin-8; Macular Edema; Ranibizumab; Transforming Growth Factor beta; Vascular Cell Adhesion Molecule-1; Vascular Endothelial Growth Factor A

The editorial team of Kidney International feels truly proud to publish Detlef Schlöndorff's legacy work. This seminal paper with Lee and Schlöndorff as joint senior authors revealed the importance of crosstalks between different glomerular cell types in diabetic kidney disease. Furthermore, they showed that bone morphogenetic protein (BMP) and activin membrane-bound inhibitor, an endogenous modulator of transforming growth factor-β signaling, plays a cell type-specific role and may be a good target for intervention against diabetic kidney disease.

Topics: Diabetes Mellitus; Diabetic Nephropathies; Humans; Kidney Glomerulus; Membrane Proteins; Podocytes; Transforming Growth Factor beta; Transforming Growth Factors

Introduction: Chronic hyperglycemia as the main link in DM pathogenesis leads to systemic vessels and nerves lesion with chronic bone complications development consequently. The aim: To evaluate influence of hyperglycemia on reparative osteogenesis after perforated tibial fracture in rats.. Materials and methods: A total of 30 white adult rats were subdivided into two groups: 15 healthy rats in Group 1 (control) and 15 rats with alloxan induced hyperglycemia in Group 2 (investigated) and were carried out of experiment on the 10th, 20th and 30th day after the fracture. Hyperglycemia in rats was verificated as the postprandial glycemic rate ≥ 8,0 mmol/l. Tibia diaphysis fracture was modeled by a cylindrical defect with a diameter of 2 mm with portable frezer. Morphological evaluation. A complex morphological studies included histological, morphometric and immunohistochemical examination.. Results: This is confirmed by an increase in MMP-9 expression in connective tissue, a decrease in TGF-β expression in all phases, an increase in the expression of CD3 and CD20 and a marked decrease in the expression of all vascular markers. During hyperglycemia, incomplete blood supply to the tissues occurs, necrosis of bone and soft tissues develop in the area of the fracture, the reparative reaction slows down considerably and manifests itself in the development of fibrous and, less commonly, cartilage tissue.. Conclusions: In hyperglycemia rats, there was a delay in the callus formation, a decrease in proliferation and ossification, and a slowdown in the processes of angiogenesis.

Topics: Animals; Antigens, CD20; Bone and Bones; Bony Callus; CD3 Complex; Diabetes Mellitus; Disease Models, Animal; Matrix Metalloproteinase 9; Neovascularization, Physiologic; Osteogenesis; Rats; Tibial Fractures; Transforming Growth Factor beta

A recent multicenter study led by our institution demonstrated that local recurrence of non-small cell lung cancer (NSCLC) was significantly more frequent in patients with diabetes, raising the possibility of different tumor biology in diabetics. Epithelial-to-mesenchymal transition (EMT) plays a key role in local tumor recurrence and metastasis. In the present study, we investigated differences of tumor microenvironment between patients with and without diabetes by examining expression of EMT markers. Seventy-nine NSCLC patients were selected from the cohort of our early multicenter study. These patients were classified into 4 groups: 39 with adenocarcinoma with (n = 19) and without (n = 20) diabetes, and 40 with squamous cell carcinoma with (n = 20) and without (n = 20) diabetes. Immunohistochemical expression of eight EMT markers was analyzed, including transforming growth factor-beta (TGF-β), epidermal growth factor receptor (EGFR), insulin-like growth factor 1 receptor (IGF-1R), vimentin, E-cadherin, N-cadherin, HtrA1, and beta-catenin. Five markers (E-cadherin, HtrA1, TGF-β, IGF-1R and vimentin) demonstrated significantly higher expression in diabetics than in non-diabetics in both histology types. N-cadherin had higher expression in diabetics, though the difference did not reach statistical significance. EGFR showed a higher expression in diabetics in squamous cell carcinoma only. Beta-catenin was the only marker with no difference in expression between diabetics versus non-diabetics. Our findings suggest that diabetes is associated with enhanced EMT in NSCLC, which may contribute to growth and invasiveness of NSCLC.

Topics: Adenocarcinoma; Aged; beta Catenin; Biomarkers, Tumor; Cadherins; Carcinoma, Non-Small-Cell Lung; Carcinoma, Squamous Cell; Diabetes Mellitus; Epithelial-Mesenchymal Transition; ErbB Receptors; Female; Gene Expression Regulation, Neoplastic; Humans; Lung Neoplasms; Male; Neoplasm Recurrence, Local; Transforming Growth Factor beta; Vimentin

The introduction of β-cell autoantigens via the gut through Lactococcus lactis (L. lactis) has been demonstrated to be a promising approach for diabetes reversal in NOD mice. Here we show that a combination therapy of low-dose anti-CD3 with a clinical-grade self-containing L. lactis, appropriate for human application, secreting human proinsulin and interleukin-10, cured 66% of mice with new-onset diabetes, which is comparable to therapy results with plasmid-driven L. lactis Initial blood glucose concentrations (<350 mg/dL) and insulin autoantibody positivity were predictors of the stable reversal of hyperglycemia, and decline in insulin autoantibody positivity was an immune biomarker of therapeutic outcome. The assessment of the immune changes induced by the L. lactis-based therapy revealed elevated frequencies of CD4

Topics: Animals; Antibodies; Antibodies, Neutralizing; Blood Glucose; CD3 Complex; CD4-Positive T-Lymphocytes; CTLA-4 Antigen; Diabetes Mellitus; Disease Models, Animal; Forkhead Transcription Factors; Glucose Tolerance Test; Immune Tolerance; Interleukin-10; Lactobacillus; Lymphocyte Activation; Mice; Mice, Inbred NOD; Pancreas; Proinsulin; T-Lymphocytes, Regulatory; Transforming Growth Factor beta

Lysophosphatidic acid (LPA) is known to regulate various biological responses by binding to LPA receptors. The serum level of LPA is elevated in diabetes, but the involvement of LPA in the development of diabetes and its complications remains unknown. Therefore, we studied LPA signaling in diabetic nephropathy and the molecular mechanisms involved. The expression of autotaxin, an LPA synthesis enzyme, and LPA receptor 1 was significantly increased in both mesangial cells (SV40 MES13) maintained in high-glucose media and the kidney cortex of diabetic db/db mice. Increased urinary albumin excretion, increased glomerular tuft area and volume, and mesangial matrix expansion were observed in db/db mice and reduced by treatment with ki16425, a LPA receptor 1/3 antagonist. Transforming growth factor (TGF)β expression and Smad-2/3 phosphorylation were upregulated in SV40 MES13 cells by LPA stimulation or in the kidney cortex of db/db mice, and this was blocked by ki16425 treatment. LPA receptor 1 siRNA treatment inhibited LPA-induced TGFβ expression, whereas cells overexpressing LPA receptor 1 showed enhanced LPA-induced TGFβ expression. LPA treatment of SV40 MES13 cells increased phosphorylated glycogen synthase kinase (GSK)3β at Ser9 and induced translocation of sterol regulatory element-binding protein (SREBP)1 into the nucleus. Blocking GSK3β phosphorylation inhibited SREBP1 activation and consequently blocked LPA-induced TGFβ expression in SV40 MES13 cells. Phosphorylated GSK3β and nuclear SREBP1 accumulation were increased in the kidney cortex of db/db mice and ki16425 treatment blocked these pathways. Thus, LPA receptor 1 signaling increased TGFβ expression via GSK3β phosphorylation and SREBP1 activation, contributing to the development of diabetic nephropathy.

Topics: Animals; Cell Line; Diabetes Mellitus; Diabetic Nephropathies; Disease Models, Animal; Disease Progression; Glycogen Synthase Kinase 3 beta; Isoxazoles; Kidney Cortex; Lysophospholipids; Male; Mice, Inbred C57BL; Phosphoric Diester Hydrolases; Phosphorylation; Propionates; Receptors, Lysophosphatidic Acid; RNA Interference; Signal Transduction; Smad2 Protein; Smad3 Protein; Sterol Regulatory Element Binding Protein 1; Time Factors; Transfection; Transforming Growth Factor beta

Essentials Endothelial protein C receptor (EPCR) promotes diabetic nephropathy (DN) outcome improvement. Renal expression and shedding of EPCR were measured in diabetic patients with or without DN. Inhibition of metalloproteinase-driven EPCR shedding restored glomerular endothelium phenotype. EPCR shedding through metalloproteinase ADAM17 contributes to the worsening of DN.. Background Diabetic nephropathy (DN) represents the leading cause of end-stage renal disease. The endothelial protein C receptor (EPCR) and its ligand (activated protein C) have been shown to ameliorate the phenotype of DN in mice. EPCR activity can be regulated by proteolytic cleavage involving ADAMs, yielding a soluble form of EPCR (sEPCR). Objective To characterize the renal expression and shedding of EPCR during DN. Methods EPCR levels were measured in plasma, urine and biopsy samples of diabetic patients with (n = 73) or without (n = 63) DN. ADAM-induced cleavage of EPCR was investigated in vitro with a human glomerular endothelium cell line. Results DN patients showed higher plasma and urinary levels of sEPCR than diabetic controls (112.2 versus 135.2 ng mL(-1) and 94.35 versus 140.6 ng mL(-1) , respectively). Accordingly, glomerular endothelial EPCR expression was markedly reduced in patients with DN, and this was associated with increased glomerular expression of ADAM-17 and ADAM-10. In vitro, EPCR shedding was induced by incubation of glomerular endothelium in high-glucose medium, and this shedding was suppressed by ADAM-17 inhibition or silencing, which led to improved vascular endothelial cadherin (VE-cadherin) expression and reduced mRNA expression of transforming growth factor (TGF)-β. In addition, EPCR silencing led to minor effects on VE-cadherin but to a significant increase in TGF-β mRNA expression. Conclusion Inhibition of ADAM-driven glomerular EPCR shedding restored the endothelial phenotype of glomerular endothelium, whereas EPCR silencing led to enhanced expression of TGF-β, a marker of endothelial-mesenchymal transition. These findings demonstrate that EPCR shedding driven by ADAMs contributes to the worsening of DN.

Topics: ADAM10 Protein; ADAM17 Protein; Aged; Amyloid Precursor Protein Secretases; Biopsy; Cell Line; Diabetes Mellitus; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Endothelial Protein C Receptor; Endothelium; Female; Gene Silencing; Humans; Kidney; Kidney Glomerulus; Ligands; Male; Membrane Proteins; Metalloproteases; Middle Aged; Phenotype; RNA, Small Interfering; Transforming Growth Factor beta

N-acetyl-seryl-aspartyl-lysyl-proline (AcSDKP) is an endogenous antifibrotic peptide. We found that suppression of AcSDKP and induction of dipeptidyl peptidase-4 (DPP-4), which is associated with insufficient levels of antifibrotic microRNA (miR)s in kidneys, were imperative to understand the mechanisms of fibrosis in the diabetic kidneys. Analyzing streptozotocin (STZ)-induced diabetic mouse strains, diabetic CD-1 mice with fibrotic kidneys could be differentiated from less-fibrotic diabetic 129Sv mice by suppressing AcSDKP and antifibrotic miRs (miR-29s and miR-let-7s), as well as by the prominent induction of DPP-4 protein expression/activity and endothelial to mesenchymal transition. In diabetic CD-1 mice, these alterations were all reversed by AcSDKP treatment. Transfection studies in culture endothelial cells demonstrated crosstalk regulation of miR-29s and miR-let-7s against mesenchymal activation program; such bidirectional regulation could play an essential role in maintaining the antifibrotic program of AcSDKP. Finally, we observed that AcSDKP suppression in fibrotic mice was associated with induction of both interferon-γ and transforming growth factor-β signaling, crucial molecular pathways that disrupt antifibrotic miRs crosstalk. The present study provides insight into the physiologically relevant antifibrotic actions of AcSDKP via antifibrotic miRs; restoring such antifibrotic programs could demonstrate potential utility in combating kidney fibrosis in diabetes.

Topics: Animals; Diabetes Mellitus; Dipeptidyl Peptidase 4; Dipeptidyl-Peptidase IV Inhibitors; Endothelial Cells; Fibroblast Growth Factor 1; Fibrosis; Humans; Interferon-gamma; Kidney; Mice; MicroRNAs; Microvessels; Models, Biological; Oligopeptides; Phosphorylation; Signal Transduction; Transforming Growth Factor beta; Up-Regulation

1-[4-[2-(4-Bromobenzene-sulfonamino)ethyl]phenylsulfonyl]-3-(trans-4-methylcyclohexyl) urea (G004, CAS865483-06-3) is a synthetic sulfonylurea, incorporating the hypoglycemic active structure of glimepiride (CAS 93479-97-1) and anti-TXA2 receptor (TP) active structure of BM-531(CAS 284464-46-6). In this study, we evaluated the effect of G004 on hyperglycemia and dyslipidemia as well as diabetic nephropathy (DN) in db/db mice by gavage over 90 consecutive days of treatment. The fasting blood glucose (FBG), glucose, and insulin tolerance as well as dyslipidemia were effectively ameliorated in db/db mice treated with G004. Interestingly, renal histological results of db/db mice revealed that G004 markedly reversed the expansion of mesangial extracellular matrix (ECM), the early hallmark of DN. Indeed, G004 treatment downregulated the renal expressions of type 4 collagen (Col IV) and transforming growth factor-β1 (TGF-β1) in db/db mice. In addition, imbalance in expressions of matrix metalloproteinase-9 (MMP-9) and its tissue inhibitor-1 (TIMP-1) in db/db mice kidneys was observed. However, G004 increased and decreased the expressions of MMP-9 and TIMP-1, respectively. It is well known that TGF-β pathway signaling plays an essential role in hyperglycemia-induced cell protein synthesis. On the other hand, MMP/TIMP system is responsible for the breakdown and turnover of ECM. Thus, we speculate that G004 possibly attenuated ECM accumulation via remodeling the synthesis and degradation of ECM component Col IV through modulation in TGF-β1 and MMP-9/TIMP-1 expressions in kidneys of db/db mice. Results from this study provide a strong rationale for G004 to be an efficient glucose-controlling agent with significant reno-protective properties.

Topics: Animals; Blood Glucose; Cholesterol; Collagen Type IV; Diabetes Mellitus; Diabetic Nephropathies; Disease Models, Animal; Dyslipidemias; Hyperglycemia; Hypoglycemic Agents; Kidney; Liver; Male; Matrix Metalloproteinase 9; Mice; Organ Size; Protective Agents; Sulfonylurea Compounds; Tissue Inhibitor of Metalloproteinase-1; Transforming Growth Factor beta; Triglycerides

Toll-like receptors (TLRs) under diabetic conditions trigger inflammation and impair immunity. In the present study, we looked at the expression of TLRs (2 and 4) and their adaptors in Normal Glucose Tolerant (NGT), Newly Diagnosed Type-2 Diabetic (NDD) and Known Type-2 Diabetic (KDM) subjects. We also estimated TLR induced cytokine secretion, cellular activation and apoptosis. Surface expression of TLR2 and 4 was significantly reduced in the B cells of the NDD subjects and was associated with decreased cellular activation and cytokine secretion (TNF-α and IL-6). This impairment was not due to B cell deficiency or apoptosis or immunosuppressive cytokine (IL-10 and TGF-β) secretion. However, the upregulation of immunomodulatory enzymes (Arg-1, HO-1 and IDO) could probably account for the reduced TLR expression. The defective TLR signalling was largely ameliorated in the KDM group which might be due to the use the anti-diabetic drugs which have anti-inflammatory effect.

Topics: Adult; Antigens, CD; Antigens, Differentiation, T-Lymphocyte; Apoptosis; B-Lymphocytes; Cells, Cultured; Diabetes Mellitus; Female; Humans; Indoleamine-Pyrrole 2,3,-Dioxygenase; Interleukin-10; Interleukin-6; Lectins, C-Type; Male; Middle Aged; Signal Transduction; Toll-Like Receptor 2; Toll-Like Receptor 4; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

Several studies suggest that one possible cause of impaired wound healing is failed or insufficient lymphangiogenesis, that is the formation of new lymphatic capillaries. Although many mathematical models have been developed to describe the formation of blood capillaries (angiogenesis) very few have been proposed for the regeneration of the lymphatic network. Moreover, lymphangiogenesis is markedly distinct from angiogenesis, occurring at different times and in a different manner. Here a model of five ordinary differential equations is presented to describe the formation of lymphatic capillaries following a skin wound. The variables represent different cell densities and growth factor concentrations, and where possible the parameters are estimated from experimental and clinical data. The system is then solved numerically and the results are compared with the available biological literature. Finally, a parameter sensitivity analysis of the model is taken as a starting point for suggesting new therapeutic approaches targeting the enhancement of lymphangiogenesis in diabetic wounds. The work provides a deeper understanding of the phenomenon in question, clarifying the main factors involved. In particular, the balance between TGF-β and VEGF levels, rather than their absolute values, is identified as crucial to effective lymphangiogenesis. In addition, the results indicate lowering the macrophage-mediated activation of TGF-β and increasing the basal lymphatic endothelial cell growth rate, inter alia, as potential treatments. It is hoped the findings of this paper may be considered in the development of future experiments investigating novel lymphangiogenic therapies.

Topics: Diabetes Mellitus; Humans; Lymphangiogenesis; Lymphatic Vessels; Macrophages; Models, Biological; Skin; Transforming Growth Factor beta; Vascular Endothelial Growth Factor A; Wound Healing

Mechanisms of restenosis in type 2 diabetes mellitus (T2DM) are incompletely elucidated, but advanced glycation end-product (AGE)-induced vascular remodeling likely contributes. We tested the hypothesis that AGE-related collagen cross-linking (ARCC) leads to increased downstream vascular resistance and altered in-stent hemodynamics, thereby promoting neointimal hyperplasia (NH) in T2DM. We proposed that decreasing ARCC with ALT-711 (Alagebrium) would mitigate this response. Abdominal aortic stents were implanted in Zucker lean (ZL), obese (ZO), and diabetic (ZD) rats. Blood flow, vessel diameter, and wall shear stress (WSS) were calculated after 21 days, and NH was quantified. Arterial segments (aorta, carotid, iliac, femoral, and arterioles) were harvested to detect ARCC and protein expression, including transforming growth factor-β (TGF-β) and receptor for AGEs (RAGE). Downstream resistance was elevated (60%), whereas flow and WSS were significantly decreased (44% and 56%) in ZD vs. ZL rats. NH was increased in ZO but not ZD rats. ALT-711 reduced ARCC and resistance (46%) in ZD rats while decreasing NH and producing similar in-stent WSS across groups. No consistent differences in RAGE or TGF-β expression were observed in arterial segments. ALT-711 modified lectin-type oxidized LDL receptor 1 but not RAGE expression by cells on decellularized matrices. In conclusion, ALT-711 decreased ARCC, increased in-stent flow rate, and reduced NH in ZO and ZD rats through RAGE-independent pathways. The study supports an important role for AGE-induced remodeling within and downstream of stent implantation to promote enhanced NH in T2DM.

Topics: Animals; Aorta, Abdominal; Collagen; Diabetes Mellitus; Glycation End Products, Advanced; Graft Occlusion, Vascular; Male; Neointima; Obesity; Rats; Rats, Zucker; Receptor for Advanced Glycation End Products; Shear Strength; Stents; Stress, Mechanical; Thiazoles; Transforming Growth Factor beta; Vascular Resistance

Fibrosis is one postulated pathway by which diabetes produces cardiac and other systemic complications. Our aim was to determine which metabolic parameters are associated with circulating fibrosis-related biomarkers transforming growth factor-β (TGF-β) and procollagen type III N-terminal propeptide (PIIINP).. We used linear regression to determine the cross-sectional associations of diverse metabolic parameters, including fasting glucose, fasting insulin, body mass index, fatty acid binding protein 4, and non-esterified fatty acids, with circulating levels of TGF-β (n = 1559) and PIIINP (n = 3024) among community-living older adults in the Cardiovascular Health Study.. Among the main metabolic parameters we examined, only fasting glucose was associated with TGF-β (P = 0.03). In contrast, multiple metabolic parameters were associated with PIIINP, including fasting insulin, body mass index, and non-esterified fatty acids (P<0.001, P<0.001, P=0.001, respectively). These associations remained statistically significant after mutual adjustment, except the association between BMI and PIIINP.. Isolated hyperglycemia is associated with higher serum concentrations of TGF-β, while a broader phenotype of insulin resistance is associated with higher serum PIIINP. Whether simultaneous pharmacologic targeting of these two metabolic phenotypes can synergistically reduce the risk of cardiac and other manifestations of fibrosis remains to be determined.

Topics: Aged; Aged, 80 and over; Biomarkers; Blood Glucose; Cardiovascular System; Cross-Sectional Studies; Diabetes Complications; Diabetes Mellitus; Fatty Acids, Nonesterified; Female; Fibrosis; Health; Humans; Insulin; Insulin Resistance; Male; Metabolic Diseases; Peptide Fragments; Procollagen; Transforming Growth Factor beta

We recently identified endotrophin as an adipokine with potent tumour-promoting effects. However, the direct effects of local accumulation of endotrophin in adipose tissue have not yet been studied. Here we use a doxycycline-inducible adipocyte-specific endotrophin overexpression model to demonstrate that endotrophin plays a pivotal role in shaping a metabolically unfavourable microenvironment in adipose tissue during consumption of a high-fat diet (HFD). Endotrophin serves as a powerful co-stimulator of pathologically relevant pathways within the 'unhealthy' adipose tissue milieu, triggering fibrosis and inflammation and ultimately leading to enhanced insulin resistance. We further demonstrate that blocking endotrophin with a neutralizing antibody ameliorates metabolically adverse effects and effectively reverses metabolic dysfunction induced during HFD exposure. Collectively, our findings demonstrate that endotrophin exerts a major influence in adipose tissue, eventually resulting in systemic elevation of pro-inflammatory cytokines and insulin resistance, and the results establish endotrophin as a potential target in the context of metabolism and cancer.

Topics: Adipocytes; Adipose Tissue; Adult; Animals; Collagen Type VI; Diabetes Mellitus; Diet, High-Fat; Energy Metabolism; Female; Fibrosis; Gene Expression; Humans; Inflammation; Insulin Resistance; Male; Matrix Metalloproteinase 12; Mice; Mice, Inbred C57BL; Mice, Transgenic; Microscopy, Confocal; Middle Aged; Obesity; Peptide Fragments; Reverse Transcriptase Polymerase Chain Reaction; Transforming Growth Factor beta

Glomerular nodular lesions, known as Kimmelstiel-Wilson nodules, are a pathological hallmark of progressive human diabetic nephropathy. We have induced severe diabetes in pigs carrying a dominant-negative mutant hepatocyte nuclear factor 1-alpha (HNF1α) P291fsinsC, a maturity-onset diabetes of the young type-3 (MODY3) gene in humans. In this model, glomerular pathology revealed that formation of diffuse glomerular nodules commenced as young as 1 month of age and increased in size and incidence until the age of 10 months, the end of the study period. Immunohistochemistry showed that the nodules consisted of various collagen types (I, III, IV, V and VI) with advanced glycation end-product (AGE) and Nε-carboxymethyl-lysine (CML) deposition, similar to those in human diabetic nodules, except for collagen type I. Transforming growth factor-beta (TGF-β) was also expressed exclusively in the nodules. The ultrastructure of the nodules comprised predominant interstitial-type collagen deposition arising from the mesangial matrices. Curiously, these nodules were found predominantly in the deep cortex. However, diabetic pigs failed to show any of the features characteristic of human diabetic nephropathy; e.g., proteinuria, glomerular basement membrane thickening, exudative lesions, mesangiolysis, tubular atrophy, interstitial fibrosis, and vascular hyalinosis. The pigs showed only Armanni-Ebstein lesions, a characteristic tubular manifestation in human diabetes. RT-PCR analysis showed that glomeruli in wild-type pigs did not express endogenous HNF1α and HNF1β, indicating that mutant HNF1α did not directly contribute to glomerular nodular formation in diabetic pigs. In conclusion, pigs harboring the dominant-negative mutant human MODY3 gene showed reproducible and distinct glomerular nodules, possibly due to AGE- and CML-based collagen accumulation. Although the pathology differed in several respects from that of human glomerular nodular lesions, the somewhat acute and constitutive formation of nodules in this mammalian model might provide information facilitating identification of the principal mechanism underlying diabetic nodular sclerosis.

Topics: Animals; Animals, Genetically Modified; Collagen; Diabetes Mellitus; Genes, Dominant; Glycation End Products, Advanced; Hepatocyte Nuclear Factor 1-alpha; Hepatocyte Nuclear Factor 1-beta; Humans; Immunohistochemistry; Inheritance Patterns; Kidney Glomerulus; Lysine; Mutation; Sus scrofa; Transforming Growth Factor beta

Transforming growth factor beta-induced (TGFBI/βIG-H3), also known as βig-H3, is a protein inducible by TGFβ1 and secreted by many cell types. It binds to collagen, forms part of the extracellular matrix and interacts with integrins on the cell surface. Recombinant TGFBI and transgenic TGFBI overexpression can promote both islet survival and function. In this study, we generated TGFBI KO mice and further assessed TGFBI function and signaling pathways in islets. Islets from KO mice were of normal size and quantity, and these animals were normoglycemic. However, KO islet survival and function was compromised in vitro. In vivo, KO donor islets became inferior to wild-type donor islets in achieving normoglycemia when transplanted into KO diabetic recipients. TGFBI KO mice were more prone to straptozotocin-induced diabetes than the wild-type counterpart. Phosphoprotein array analysis established that AKT1S1, a molecule linking the AKT and mTORC1 signaling pathways, was modulated by TGFBI in islets. Phosphorylation of four molecules in the AKT and mTORC1 signaling pathway, i.e. AKT, AKT1S1, RPS6 and EIF4EBP1, was upregulated in islets upon TGFBI stimulation. Suppression of AKT activity by a chemical inhibitor, or knockdown of AKT1S1, RPS6 and EIF4EBP1 expression by small interfering RNA, modulated islet survival, proving the relevance of these molecules in TGFBI-triggered signaling. Human genetic studies revealed that in the TGFBI gene and its vicinity, three single-nucleotide polymorphisms were significantly associated with type 1 diabetes risks, and one with type 2 diabetes risks. Our study suggests that TGFBI is a potential risk gene for human diabetes.

Topics: Animals; Diabetes Mellitus; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Extracellular Matrix Proteins; Genetic Predisposition to Disease; Humans; Islets of Langerhans; Islets of Langerhans Transplantation; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Phosphoproteins; Phosphorylation; Polymorphism, Single Nucleotide; Risk Factors; Signal Transduction; Tissue Survival; Transforming Growth Factor beta; Transforming Growth Factor beta1

The brain, in particular the hypothalamus, plays a role in regulating glucose homeostasis; however, it remains unclear whether this organ is causally and etiologically involved in the development of diabetes. Here, we found that hypothalamic transforming growth factor-β (TGF-β) production is excessive under conditions of not only obesity but also aging, which are two general etiological factors of type 2 diabetes. Pharmacological and genetic approaches revealed that central TGF-β excess caused hyperglycemia and glucose intolerance independent of a change in body weight. Further, using cell-specific genetic analyses in vivo, we found that astrocytes and proopiomelanocortin neurons are responsible for the production and prodiabetic effect of central TGF-β, respectively. Mechanistically, TGF-β excess induced a hypothalamic RNA stress response, resulting in accelerated mRNA decay of IκBα, an inhibitor of proinflammatory nuclear factor-κB. These results reveal an atypical, mRNA metabolism-driven hypothalamic nuclear factor-κB activation, a mechanism that links obesity as well as aging to hypothalamic inflammation and ultimately to type 2 diabetes.

Topics: Aging; Astrocytes; Diabetes Mellitus; Glucose Tolerance Test; Humans; Hypothalamus; NF-kappa B; Obesity; Pro-Opiomelanocortin; RNA; Stress, Physiological; Transforming Growth Factor beta

Topics: Aging; Diabetes Mellitus; Humans; Obesity; RNA; Stress, Physiological; Transforming Growth Factor beta

Aging and a high-fat diet are predisposing factors for type 2 diabetes. A study in mice suggests that dietary fat and aging lead to atypical transforming growth factor-β1 signaling in the hypothalamus, which disturbs whole-body glucose regulation.

Topics: Aging; Diabetes Mellitus; Humans; Obesity; RNA; Stress, Physiological; Transforming Growth Factor beta

In diabetes the endothelium is either chronically or transiently exposed to hyperglycemic conditions. In addition, endothelial dysfunction in diabetes is related to changes in the inflammatory response and the turnover of extracellular matrix. This study was undertaken to study the effects of inflammatory stimuli on one particular matrix component, the heparan sulfate (HS) proteoglycans (PGs) synthesized by primary human umbilical cord vein endothelial cells (HUVEC). Such cells were cultured in vitro in 5 mM and 25 mM glucose. The latter concentration was used to mimic hyperglycemic conditions in short-term experiments. HUVEC were also cultured in the presence of the inflammatory agents tumor necrosis factor α (TNF-α), interleukin 1α (IL-1α), interleukin 1β (IL-1β) and transforming growth factor β (TGF-β). The cells were labeled with (35)S-sulfate and (35)S-PGs were recovered for further analyses. The major part of the (35)S-PGs was secreted to the medium, irrespective of type of stimuli. Secreted (35)S-PGs were therefore isolated and subjected to further analyses. TNF-α and IL-1α slightly increased the release of (35)S-PGs to the culture medium, whereas IL-1β treatment gave a significant increase. The different treatments neither changed the ratio of (35)S-HS and (35)S-chondroitin sulfate (CS) nor the macromolecular properties of the (35)S-PGs. However, the (35)S-HS chains were slightly increased in size after TNF-α treatment, and slightly decreased after TGF-β treatment, but not affected by the other treatments. Compositional analysis of labeled disaccharides showed changes in the amount of 6-O-sulfated glucosamine residues after treatment with TNF-α, IL-1α and IL-1β. Western immunoblotting showed that major HSPGs recovered from these cells were collagen XVIII, perlecan and agrin, and that secretion of these distinct PGs was increased after IL-1β stimulation. Hence, short term inflammatory stimuli increased the release of HSPGs in HUVEC and affected both the size and sulfation pattern of HS, depending on type of stimuli.

Topics: Agrin; Cells, Cultured; Chondroitin Sulfates; Collagen Type XVIII; Cytokines; Diabetes Mellitus; Endothelium; Extracellular Matrix; Glucosamine; Glucose; Heparan Sulfate Proteoglycans; Human Umbilical Vein Endothelial Cells; Humans; Hyperglycemia; Interleukin-1alpha; Interleukin-1beta; Sulfur Radioisotopes; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

Recently, it has been reported that the Notch pathway is involved in the pathogenesis of diabetic nephropathy. In this study, we investigated the activation of the Notch pathway in Ins2 Akita diabetic mouse (Akita mouse) and the effects of telmisartan, an angiotensin II type1 receptor blocker, on the Notch pathway. The intracellular domain of Notch1 (ICN1) is proteolytically cleaved from the cell plasma membrane in the course of Notch activation. The expression of ICN1 and its ligand, Jagged1, were increased in the glomeruli of Akita mice, especially in the podocytes. Administration of telmisartan significantly ameliorated the expression of ICN1 and Jagged1. Telmisartan inhibited the angiotensin II-induced increased expression of transforming growth factor β and vascular endothelial growth factor A which could directly activate the Notch signaling pathway in cultured podocytes. Our results indicate that the telmisartan prevents diabetic nephropathy through the inhibition of the Notch pathway.

Topics: Angiotensin II Type 1 Receptor Blockers; Animals; Benzimidazoles; Benzoates; Calcium-Binding Proteins; Cells, Cultured; Diabetes Mellitus; Diabetic Nephropathies; Intercellular Signaling Peptides and Proteins; Jagged-1 Protein; Kidney Glomerulus; Male; Membrane Proteins; Mice; Mice, Inbred C57BL; Receptor, Notch1; Serrate-Jagged Proteins; Signal Transduction; Telmisartan; Transforming Growth Factor beta; Vascular Endothelial Growth Factor A

Foxp3(+) regulatory T cells (Tregs) originate in the thymus, but the Treg phenotype can also be induced in peripheral lymphoid organs or in vitro by stimulation of conventional CD4(+) T cells with IL-2 and TGF-β. There have been divergent reports on the suppressive capacity of these TGF-Treg cells. We find that TGF-Tregs derived from diabetes-prone NOD mice, although expressing normal Foxp3 levels, are uniquely defective in suppressive activity, whereas TGF-Tregs from control strains (B6g7) or ex vivo Tregs from NOD mice all function normally. Most Treg-typical transcripts were shared by NOD or B6g7 TGF-Tregs, except for a small group of differentially expressed genes, including genes relevant for suppressive activity (Lrrc32, Ctla4, and Cd73). Many of these transcripts form a coregulated cluster in a broader analysis of T-cell differentiation. The defect does not map to idd3 or idd5 regions. Whereas Treg cells from NOD mice are normal in spleen and lymph nodes, the NOD defect is observed in locations that have been tied to pathogenesis of diabetes (small intestine lamina propria and pancreatic lymph node). Thus, a genetic defect uniquely affects a specific Treg subpopulation in NOD mice, in a manner consistent with a role in determining diabetes susceptibility.

Topics: Animals; Cluster Analysis; Diabetes Mellitus; Gene Expression Regulation; Genetic Predisposition to Disease; Mice; Mice, Inbred NOD; T-Lymphocytes, Regulatory; Transforming Growth Factor beta

Imbalances in glucose and energy homeostasis are at the core of the worldwide epidemic of obesity and diabetes. Here, we illustrate an important role of the TGF-β/Smad3 signaling pathway in regulating glucose and energy homeostasis. Smad3-deficient mice are protected from diet-induced obesity and diabetes. Interestingly, the metabolic protection is accompanied by Smad3(-)(/-) white adipose tissue acquiring the bioenergetic and gene expression profile of brown fat/skeletal muscle. Smad3(-/-) adipocytes demonstrate a marked increase in mitochondrial biogenesis, with a corresponding increase in basal respiration, and Smad3 acts as a repressor of PGC-1α expression. We observe significant correlation between TGF-β1 levels and adiposity in rodents and humans. Further, systemic blockade of TGF-β signaling protects mice from obesity, diabetes, and hepatic steatosis. Together, these results demonstrate that TGF-β signaling regulates glucose tolerance and energy homeostasis and suggest that modulation of TGF-β activity might be an effective treatment strategy for obesity and diabetes.

Topics: Adipose Tissue, Brown; Adipose Tissue, White; Animals; Antibodies; Diabetes Mellitus; DNA-Binding Proteins; Energy Metabolism; Glucose Tolerance Test; Mice; Mice, Knockout; Mice, Obese; Mitochondria; Obesity; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; Signal Transduction; Smad3 Protein; Trans-Activators; Transcription Factors; Transforming Growth Factor beta

Diabetes is a major predictor of in-stent restenosis, which is associated with fibroproliferative remodeling of the vascular wall due to increased transforming growth factor-beta (TGF-beta) action. It is well established that thrombospondin1 (TSP1) is a major regulator of TGF-beta activation in renal and cardiac complications of diabetes. However, the role of the TSP1-TGF-beta pathway in macrovascular diabetic complications, including restenosis, has not been addressed. In mesangial cells, high glucose concentrations depress protein kinase G (PKG) activity, but not PKG-I protein, thereby downregulating transcriptional repression of TSP1. Previously, we showed that high glucose downregulates PKG-I protein expression by vascular smooth muscle cells (VSMCs) through altered NADPH oxidase signaling. In the present study, we investigated whether high glucose regulation of PKG protein and activity in VSMCs similarly regulates TSP1 expression and downstream TGF-beta activity. These studies showed that high glucose stimulates both TSP1 expression and TGF-beta bioactivity in primary murine aortic smooth muscle cells (VSMCs). TSP1 is responsible for the increased TGF-beta bioactivity under high glucose conditions, because treatment with anti-TSP1 antibody, small interfering RNA-TSP1, or an inhibitory peptide blocked glucose-mediated increases in TGF-beta activity and extracellular matrix protein (fibronectin) expression. Overexpression of constitutively active PKG, but not the PKG-I protein, inhibited glucose-induced TSP1 expression and TGF-beta bioactivity, suggesting that PKG protein expression is insufficient to regulate TSP1 expression. Together, these data establish that glucose-mediated downregulation of PKG levels stimulates TSP1 expression and enhances TGF-beta activity and matrix protein expression, which can contribute to vascular remodeling in diabetes.

Topics: Animals; Cells, Cultured; Cyclic GMP-Dependent Protein Kinases; Diabetes Mellitus; Down-Regulation; Extracellular Matrix Proteins; Gene Expression Regulation, Enzymologic; Glucose; Mice; Mice, Inbred C57BL; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; NADPH Oxidases; RNA, Messenger; Thrombospondin 1; Time Factors; Transforming Growth Factor beta; Up-Regulation

Peripheral blood CD34(+) cells from diabetic patients demonstrate reduced vascular reparative function due to decreased proliferation and diminished migratory prowess, largely resulting from decreased nitric oxide (NO) bioavailability. The level of TGF-beta, a key factor that modulates stem cell quiescence, is increased in the serum of type 2 diabetic patients. We asked whether transient TGF-beta1 inhibition in CD34(+) cells would improve their reparative ability.. To inhibit TGF-beta1 protein expression, CD34(+) cells were treated ex vivo with antisense phosphorodiamidate morpholino oligomers (TGF-beta1-PMOs) and analyzed for cell surface CXCR4 expression, cell survival in the absence of added growth factors, SDF-1-induced migration, NO release, and in vivo retinal vascular reparative ability.. TGF-beta1-PMO treatment of diabetic CD34(+) cells resulted in increased expression of CXCR4, enhanced survival in the absence of growth factors, and increased migration and NO release as compared with cells treated with control PMO. Using a retinal ischemia reperfusion injury model in mice, we observed that recruitment of diabetic CD34(+) cells to injured acellular retinal capillaries was greater after TGF-beta1-PMO treatment compared with control PMO-treated cells.. Transient inhibition of TGF-beta1 may represent a promising therapeutic strategy for restoring the reparative capacity of dysfunctional diabetic CD34(+) cells.

Topics: Animals; Antigens, CD34; Capillaries; Cell Survival; Diabetes Mellitus; Diabetic Angiopathies; Diabetic Retinopathy; Flow Cytometry; Hematopoietic Stem Cells; Humans; Mice; Morpholines; Morpholinos; Nitric Oxide; Receptors, CXCR4; Reperfusion Injury; Transforming Growth Factor beta; Transforming Growth Factor beta1

Several cells of immune system such as regulatory T cells and macrophages secrete transforming growth factor-β (TGF-β) in response to different stimuli. This cytokine has inhibitory effect on immune system and diminished production of this cytokine is associated with autoimmune disorders.. The aim of this study was to evaluate the influence of opium addiction on serum level of TGF-β in male and female diabetic and non-diabetic Wistar rats.. This experimental study was performed on normal, opium addicted, diabetic and addicted-diabetic male and female rats. Serum level of TGF-β was measured by ELISA.. The results of our study indicated that the mean serum level of TGF-β in female addicted rats was significantly increased compared to control group (p<0.004). Conversely, in male addicted rats the mean serum level of TGF-β was lower compared with control (p<0.065).. Our results suggest that opium and its derivatives have differential inductive effects on the cytokine expression in male and female rats.

Topics: Animals; Diabetes Mellitus; Diabetes Mellitus, Experimental; Female; Male; Narcotics; Opioid-Related Disorders; Opium; Rats; Transforming Growth Factor beta

Many cell and tissue abnormalities in diabetes mellitus are mediated by auto- and paracrine TGFbeta which is induced by high ambient glucose and glycated proteins. In most cell types TGFbeta reduces cell proliferation and enhances apoptosis which are mediated through the TGFbeta type I receptor, Alk5. In contrast, early diabetic microangiopathy is characterized by endothelial cell proliferation. Endothelial cells are unique in expressing a second TGFbeta type I receptor, Alk1, as well as the co-receptor, endoglin which increases the affinity of the ligand to Alk1. In differentiated blood outgrowth endothelial cells from normal subjects Alk1 and endoglin are constitutively expressed. Incubation with high glucose (HG) and glycated albumin (gAlb) induces Alk5 and raises TGFbeta secretion 3-fold without affecting Alk1 or endoglin levels. This diabetic milieu accelerates cell proliferation, at least in part, through TGFbeta/Alk1-smad1/5 and probably involving VEGF as well as pro-migratory MMP2 downstream of Alk1. In contrast, HG/gAlb also increases caspase-3 activity (suggesting increased apoptosis) in part but not entirely using a TGFbeta/Alk5-smad2/3 pathway. The findings support pleiotropy of TGFbeta in endothelial cells including proliferative effects (through Alk1-smad1/5) and pro-apoptotic signals (through Alk5-smad2/3).

Topics: Activin Receptors, Type II; Apoptosis; Benzamides; Biological Assay; Caspase 3; Cell Culture Techniques; Cell Differentiation; Cell Proliferation; Cells, Cultured; Coated Materials, Biocompatible; Collagen Type I; Culture Media, Conditioned; Culture Media, Serum-Free; Diabetes Mellitus; Dioxoles; Dose-Response Relationship, Drug; Endothelial Cells; Endothelium, Vascular; Enzyme Activation; Fibronectins; Genes, Reporter; Glucose; Humans; Luciferases; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Phosphorylation; Protein Serine-Threonine Kinases; Receptor, Transforming Growth Factor-beta Type I; Receptors, Transforming Growth Factor beta; Recombinant Proteins; Smad Proteins; Time Factors; Transforming Growth Factor beta

In multicellular organisms, cell size is tightly controlled by nutrients and growth factors. Increasing ambient glucose induces enhanced protein synthesis and cell size. Continued exposure of cells to high glucose in vivo, as apparent under pathological conditions, results in cell hypertrophy and tissue damage. We demonstrate that activation of TGF-beta signaling has a central role in glucose-induced cell hypertrophy in fibroblasts and epithelial cells. Blocking the kinase activity of the TbetaRI receptor or loss of its expression prevented the effects of high glucose on protein synthesis and cell size. Exposure of cells to high glucose induced a rapid increase in cell surface levels of the TbetaRI and TbetaRII receptors and a rapid activation of TGF-beta ligand by matrix metalloproteinases, including MMP-2 and MMP-9. The consequent autocrine TGF-beta signaling in response to glucose led to Akt-TOR pathway activation. Accordingly, preventing MMP-2/MMP-9 or TGF-beta-induced TOR activation inhibited high glucose-induced cell hypertrophy.

Topics: Active Transport, Cell Nucleus; Animals; Cell Line; Cell Size; Diabetes Mellitus; Epithelial Cells; Fibroblasts; Glucose; Hyperglycemia; Hypertrophy; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Mice; Mice, Knockout; Neoplasms; Protein Kinases; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins c-akt; Rats; Receptor, Transforming Growth Factor-beta Type I; Receptor, Transforming Growth Factor-beta Type II; Receptors, Transforming Growth Factor beta; RNA Interference; Signal Transduction; Smad3 Protein; TOR Serine-Threonine Kinases; Transforming Growth Factor beta

When the homozygous active form of porcine TGF-beta1 transgene (Tgf/Tgf) (under control of the rat glucagon promoter) is introduced into the nonobese diabetic mouse (NOD) genetic background, the mice develop endocrine and exocrine pancreatic hypoplasia, low serum insulin concentrations, and impaired glucose tolerance. To identify genetic modifiers of the diabetic phenotypes, we crossed hemizygous NOD-Tgf with DBA/2J mice (D2) or C3H/HeJ mice (C3H) and used the "transgenic mice" for quantitative trait loci (QTL) analysis. Genome-wide scans of F(2)-D Tgf/Tgf (D2 x NOD) and F(2)-C Tgf/Tgf (C3H x NOD), homozygous for the TGF-beta1 transgene, identified six statistically significant modifier QTLs: one QTL (Tdn1) in F(2)-D Tgf/Tgf, and five QTLs (Tcn1 to Tcn5) in F(2)-C Tgf/Tgf. Tdn1 (Chr 13, LOD = 4.39), and Tcn3 (Chr 2, LOD = 4.94) showed linkage to body weight at 8 weeks of age. Tcn2 (Chr 7, LOD = 4.38) and Tcn4 (Chr 14, LOD = 3.99 and 3.78) showed linkage to blood glucose (BG) concentrations in ipGTT at 30, 0, and 120 min, respectively. Tcn1 (Chr 1, LOD = 4.41) and Tcn5 (Chr 18, LOD = 4.99) showed linkage to serum insulin concentrations in ipGTT at 30 min. Tcn2 includes the candidate gene, uncoupling protein 2 (Ucp2), and shows linkage to Ucp2 mRNA levels in the soleus muscle (LOD = 4.90). Identification of six QTLs for diabetes-related traits in F(2)-D Tgf/Tgf and F(2)-C Tgf/Tgf raises the possibility of identifying candidate susceptibility genes and new targets for drug development for human type 2 diabetes.

Topics: Animals; Blood Glucose; Body Weight; Chromosomes, Mammalian; Crosses, Genetic; Diabetes Mellitus; Female; Food Deprivation; Genome; Homozygote; Insulin; Lod Score; Male; Mice; Quantitative Trait Loci; Quantitative Trait, Heritable; Sex Characteristics; Swine; Transforming Growth Factor beta; Transgenes

In early diabetic renal injury, there is podocyte drop-out (but no decrease in the number of other glomerular cells) which is thought to cause glomerular proteinuria and subsequent diabetic glomerular injury. We tested the hypothesis that early diabetic podocyte injury is caused, in part, by downregulation of bone morphogenetic protein-7 (BMP7) and loss of its autocrine function in murine podocytes. High glucose (HG; 25 mM) induces rounding of differentiated podocytes and changes in the distribution of F-actin but without quantitative changes in E-cadherin and the podocyte markers podocin, CD2AP, Neph1, or synaptopodin. HG reduces BMP7 secretion and activity but does not affect BMP receptor levels in murine podocytes. In these cells, BMP7 effectively activates smad5 (but not smad1) and raises p38 phosphorylation [which is also increased by transforming growth factor-beta (TGF-beta)]. HG as well as TGF-beta raise caspase-3 activity, increase apoptosis, and reduce cell survival which is, in part, blocked by BMP7. Knockdown and forced expression studies indicate that smad5 is required as well as sufficient for these actions of BMP7. These findings indicate that BMP7 is a differentiation and survival factor for podocytes, requires smad5, and can reduce diabetic podocyte injury.

Topics: Actins; Animals; Autocrine Communication; Bone Morphogenetic Protein 7; Bone Morphogenetic Proteins; Caspase 3; Cell Differentiation; Cell Shape; Cell Survival; Cells, Cultured; Cytoprotection; Cytoskeleton; Diabetes Mellitus; Diabetic Nephropathies; Dose-Response Relationship, Drug; Down-Regulation; Enzyme Activation; Glucose; Kidney; Mice; p38 Mitogen-Activated Protein Kinases; Phenotype; Phosphorylation; Podocytes; RNA, Small Interfering; Smad5 Protein; Transforming Growth Factor beta

The bone-related protein osteoprotegerin (OPG) may be involved in the development of vascular calcifications, especially in diabetes, where it has been found in increased amounts in the arterial wall. Experimental studies suggest that members of the TGF-superfamily are involved in the transformation of human vascular smooth muscle cells (HVSMC) to osteoblast-like cells. In this study, we evaluated the effect of BMP-2, BMP-7 and transforming growth factor beta (TGF-beta1) on the secretion and mRNA expression of OPG and its ligands receptor activator of nuclear factor-kappabeta ligand (RANKL) and TNF-related apoptosis-inducing ligand (TRAIL) in HVSMC. All three growth factors decreased OPG protein production significantly; these results were paralleled by reduced OPG mRNA expression. TRAIL mRNA levels were also decreased. RANKL mRNA expression declined when treated with TGF-beta1 but were increased by both BMPs. Members of the TGF-superfamily, i.e. TGF-beta1, BMP-2 and BMP-7 exert effects on OPG and its ligands, indicating that these peptides may be involved in the development of vascular calcifications. The downregulation of OPG by these peptides does, however, not suggest that these factors are directly involved in OPG accumulation in diabetes.

Topics: Actins; Bone Morphogenetic Proteins; Calcinosis; Cells, Cultured; Diabetes Mellitus; Humans; Muscle, Smooth, Vascular; Osteoprotegerin; RANK Ligand; RNA, Messenger; TNF-Related Apoptosis-Inducing Ligand; Transforming Growth Factor beta

Identification of signaling pathways that maintain and promote adult pancreatic islet functions will accelerate our understanding of organogenesis and improve strategies for treating diseases like diabetes mellitus. Previous work has implicated transforming growth factor-beta (TGF-beta) signaling as an important regulator of pancreatic islet development, but has not established whether this signaling pathway is required for essential islet functions in the adult pancreas. Here we describe a conditional system for expressing Smad7, a potent inhibitor of TGF-beta signaling, to identify distinct roles for this pathway in adult and embryonic beta cells. Smad7 expression in Pdx1+ embryonic pancreas cells resulted in striking embryonic beta cell hypoplasia and neonatal lethality. Conditional expression of Smad7 in adult Pdx1+ cells reduced detectable beta cell expression of MafA, menin, and other factors that regulate beta cell function. Reduced pancreatic insulin content and hypoinsulinemia produced overt diabetes that was fully reversed upon resumption of islet TGF-beta signaling. Thus, our studies reveal that TGF-beta signaling is crucial for establishing and maintaining defining features of mature pancreatic beta cells.

Topics: Aging; Animals; Bone Morphogenetic Proteins; Cell Differentiation; Diabetes Mellitus; Embryo, Mammalian; Gene Expression Regulation, Developmental; Growth Differentiation Factors; Homeodomain Proteins; Islets of Langerhans; Maf Transcription Factors, Large; Mice; Mice, Transgenic; Signal Transduction; Smad7 Protein; Trans-Activators; Transforming Growth Factor beta

The peroxisome proliferator activating nuclear receptors (PPAR) are activated in the context of inflammation, diabetes or normal pregnancy. Renal mesangial cells express PPAR-gamma which upon activation are capable of exerting anti-inflammatory effects. We investigated the effect of in vivo treatment by rosiglitazone on angiotensin II (A-II) stimulated manifestations of inflammation in cultured renal mesangial cells, such as proliferation, apoptosis, TGF-beta1 production and nuclear factor kappaB (NF-kappaB) activation, in the situation of pregnancies, complicated or not with diabetes.. Mesangial cells were isolated from the following groups, receiving or not 5 mg/kg rosiglitazone for 20 days: normal controls, normal pregnant rats, those with streptozotocine induced diabetes and pregnant diabetic rats. Proliferation was assessed by 3H-thymidine incorporation. Apoptosis was evaluated by TUNEL assay. AT-1/AT-2 receptor density was assessed by 125I-AT-2 labelling, TGF-beta and NF-kappaB by specific ELISAs.. Rosiglitazone pretreatment resulted in significantly decreased proliferation, apoptosis and reduced responsiveness to A-II stimulation in cultures from controls, pregnant rats and non-pregnant diabetic animals. In the pregnant diabetic group which received rosiglitazone prior to sacrifice, responsiveness to A-II was completely blunted. Moderate attenuation of TGF-beta synthesis and significant decrease in the levels of NF-kappaB in mesangial cell nuclei were observed in all rosiglitazone treated groups.. PPAR-gamma activation by rosiglitazone resulted in decreased manifestation of inflammatory hallmarks, including inhibition of mesangial cell proliferation, downregulation of apoptosis and blunted responsiveness to A-II. These anti-inflammatory renoprotective effects were maximally expressed in cultures from pregnant diabetic animals. The therapeutic relevance of these observations is a matter of further investigations.

Topics: Animals; Apoptosis; Cell Proliferation; Cells, Cultured; Diabetes Mellitus; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Female; Glomerular Mesangium; In Situ Nick-End Labeling; PPAR gamma; Pregnancy; Pregnancy, Animal; Probability; Rats; Rats, Sprague-Dawley; Reference Values; Risk Factors; Rosiglitazone; Sensitivity and Specificity; Statistics, Nonparametric; Streptozocin; Thiazolidinediones; Transforming Growth Factor beta

The effects of calcium channel blockers (CCBs) on complications associated with diabetes mellitus (DM) have been well studied in clinical and basic science investigations. Cardiovascular complications are a common feature of type 2 DM, and insulin resistance is an early clinical manifestation of type 2 DM. CCBs are widely used to treat cardiovascular diseases in patients with DM. In this study, we used a spontaneous type 2 diabetic rat model, Otsuka Long-Evans Tokushima Fatty (OLETF) rats, at a highly insulin-resistant stage with modest hyperglycemia. We examined cardiac expression of transforming growth factor-beta(1) (TGFbeta(1)) and endothelin-1 (ET-1) in male OLETF rats. At 8 weeks of age, OLETF rats were treated for 12 weeks with the long-acting CCB benidipine (1 mg/kg/day or 3 mg/kg/day, po, n = 12), with hydralazine hydrochloride (3 mg/kg/day, po, n = 12), or with vehicle (OLETF, n = 12), and male age-matched genetic control Long-Evans Tokushima Otsuka (LETO, n = 12) rats were used. Blood pressure was significantly higher in OLETF rats than in LETO rats, and benidipine treatment at both dosages in OLETF rats for 12 weeks did not significantly reduce blood pressure, whereas hydralazine treatment significantly lowered blood pressure in OLETF rats. Hydralazine and both dosages of benidipine significantly reduced upregulated cardiac ET-1 levels in OLETF rats. Plasma and cardiac TGFbeta1 levels were remarkably higher in OLETF rats compared with LETO rats and were normalized by treatment with benidipine (3 mg/kg/day). Our results suggest that CCBs are effective in normalizing upregulated cardiac TGFbeta1 and ET-1 levels at the insulin-resistant stage in OLETF rats, which may improve cardiac morphology and function in this rat model without altering blood pressure and plasma glucose levels. In contrast, hydralazine treatment also normalizes cardiac ET-1 levels while significantly reducing blood pressure.

Topics: Animals; Blood Glucose; Blood Pressure; Calcium Channel Blockers; Diabetes Mellitus; Dihydropyridines; Dose-Response Relationship, Drug; Endothelin-1; Endothelium, Vascular; Hydrazines; Insulin; Male; Random Allocation; Rats; Rats, Inbred OLETF; Rats, Long-Evans; Transforming Growth Factor beta

Wound healing in diabetes is a complex process, characterised by a chronic inflammation phase. The exact mechanism by which this occurs is not fully understood, and whilst several treatments for healing diabetic wounds exist, very little research has been conducted towards the causes of the extended inflammation phase. We describe a mathematical model which offers a possible explanation for diabetic wound healing in terms of the distribution of macrophage phenotypes being altered in the diabetic patient compared to normal wound repair. As a consequence of this, we put forward a suggestion for treatment based on rectifying the macrophage phenotype imbalance.

Topics: Algorithms; Animals; Cell Movement; Diabetes Mellitus; Humans; Inflammation; Macrophages; Models, Biological; Transforming Growth Factor beta; Wound Healing

Vasoactive intestinal peptide (VIP) is a potent anti-inflammatory agent with immunoregulatory properties, skewing the immune response to a Th2 pattern of cytokine production. Here, we studied the effect of treatment with VIP in the development of diabetes in nonobese diabetic (NOD) mice, an animal model of type 1 diabetes. Mice treated with VIP from 4 weeks of age did not develop diabetes and showed milder insulitis than nontreated mice. The protective mechanism of VIP was associated with a reduction in the circulating levels of Th1 cytokines. In the pancreas of VIP-treated animals, regulatory T cell markers predominate, as indicated by the upregulation of FoxP3 and transforming growth factor-beta (TGF-beta), and the downregulation of the transcription factor, T-bet. These findings indicate that VIP restores tolerance to pancreatic islets by promoting the local differentiation and function of regulatory T cells.

Topics: Animals; Autoimmunity; Cell Proliferation; Diabetes Mellitus; Female; Forkhead Transcription Factors; Immune Tolerance; Insulin; Mice; Mice, Inbred NOD; Pancreas; Th1 Cells; Th2 Cells; Transforming Growth Factor beta; Vasoactive Intestinal Peptide

Diabetes mellitus adversely affects the outcomes in patients with myocardial infarction (MI), due in part to the exacerbation of left ventricular (LV) remodeling. Although angiotensin II type 1 receptor blocker (ARB) has been demonstrated to be effective in the treatment of heart failure, information about the potential benefits of ARB on advanced LV failure associated with diabetes is lacking. To induce diabetes, male mice were injected intraperitoneally with streptozotocin (200 mg/kg). At 2 weeks, anterior MI was created by ligating the left coronary artery. These animals received treatment with olmesartan (0.1 mg/kg/day; n = 50) or vehicle (n = 51) for 4 weeks. Diabetes worsened the survival and exaggerated echocardiographic LV dilatation and dysfunction in MI. Treatment of diabetic MI mice with olmesartan significantly improved the survival rate (42% versus 27%, P < 0.05) without affecting blood glucose, arterial blood pressure, or infarct size. It also attenuated LV dysfunction in diabetic MI. Likewise, olmesartan attenuated myocyte hypertrophy, interstitial fibrosis, and the number of apoptotic cells in the noninfarcted LV from diabetic MI. Post-MI LV remodeling and failure in diabetes were ameliorated by ARB, providing further evidence that angiotensin II plays a pivotal role in the exacerbated heart failure after diabetic MI.

Topics: Angiotensin II Type 1 Receptor Blockers; Animals; Apoptosis; Blood Glucose; Diabetes Mellitus; Echocardiography; Male; Metalloproteases; Mice; Myocardial Infarction; Organ Size; Receptor, Angiotensin, Type 1; Streptozocin; Survival Rate; Tissue Inhibitor of Metalloproteinases; Transforming Growth Factor beta; Ventricular Remodeling

Besides the classical cardiovascular diseases, high levels of blood glucose directly interfere with cardiomyocytes. The mechanisms responsible for this have not yet been explored in detail. This study aims to determine if hyperglycaemia has any impact on prominent signalling molecules and on the contractile function of cardiomyocytes. Freshly isolated cardiomyocytes from adult rats were treated with various concentrations of glucose. Formed free radicals were measured by DCF-fluorescence. TGFbeta expression and p38 MAP-kinase (MAPK) activation were measured by Western blotting. The contractile efficiency was determined by measurement of the maximal amount of cell shortening. Glucose (30 mM) caused an increase in formation of radicals, phosphorylation of p38 MAPK, and TGFbeta expression. Under conditions of low viscosity (1 cp), contractile responses to hyperglycaemia (15 mM) were not altered in contrast to control. However, enhancement of viscosity (400 cp) effected a limitation of contractile function. The responsiveness to beta-adrenoceptor stimulation did not change. Neither inhibition of p38 MAPK with SB 202190 (1 microM) nor inhibition of reactive oxygen species with vitamin C did alter these measured functional parameters. Diabetes mellitus directly influences the activation degree of prominent signalling molecules and the contractile function of adult ventricular cardiomyocytes, which results in facilitating in the development of diabetic cardiomyopathy.

Topics: Animals; Antioxidants; Ascorbic Acid; Cells, Cultured; Diabetes Mellitus; Electrophysiology; Glucose; Hyperglycemia; Imidazoles; Isoproterenol; Male; Muscle Contraction; Myocytes, Cardiac; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Protein Kinase Inhibitors; Pyridines; Rats; Rats, Wistar; Reactive Oxygen Species; Receptors, Adrenergic, beta; Signal Transduction; Transforming Growth Factor beta

Topics: Diabetes Mellitus; Fibrosis; Humans; Hypertension; Obesity; Risk Factors; Schistosomiasis; Smoking; Somatostatin; Transforming Growth Factor beta; Transforming Growth Factor beta1

To assess the effects of the cytokines interleukin-1 (IL-1), transforming growth factor-beta (TGF-beta), and alpha-smooth muscle actin (alpha-SMA) in lens epithelial cells (LECs) in normal and diabetic eyes.. Department of Ophthalmology, University of Tokyo School of Medicine, Tokyo, Japan.. Ten eyes of 10 patients with diabetic mellitus and 20 normal eyes of 20 patients with senile cataract were studied. The anterior lens capsules with LECs obtained by capsulotomy during cataract surgery were cultured. The LECs obtained immediately after surgery and on the third day of culture were immunohistologically studied to assess the activities of the cytokines.. Interleukin-1 and TGF-beta staining showed a low level activity in some LECs in diabetic eyes but only a minimum level of activity in those in normal eyes. During culture, LECs in diabetic eyes became small and transformed into fusiform and fibroblast-like cells, and these cells were strongly stained for IL-1 and TGF-beta. Normal eyes showed little changes in cell morphology and were weakly stained for IL-1 and TGF-beta. Both with culture and with no culture, alpha-SMA showed only minimal activity in both diabetic and normal eyes, with no difference.. Lens epithelial cells after cataract surgery had low IL-1 and TGF-beta activities, and these activities increased during culture. Diabetic eyes showed higher cytokine activities and more marked morphologic changes than normal eyes, suggesting that increased proliferative activity and increased cytokine activity of LECs contribute to strong anterior capsule contraction in diabetic eyes.

Topics: Actins; Aged; Cataract Extraction; Cell Culture Techniques; Diabetes Mellitus; Diabetic Retinopathy; Epithelial Cells; Humans; Immunoenzyme Techniques; Interleukin-1; Lens, Crystalline; Transforming Growth Factor beta

CD4+CD25+ regulatory T cells are essential in the protection from organ-specific autoimmune diseases. In the pancreas, they inhibit actions of autoreactive T cells and thereby prevent diabetes progression. The signals that control the generation, the maintenance, or the expansion of regulatory T cell pool in vivo remain poorly understood. Here we show that a transient pulse of transforming growth factor beta (TGF-beta) in the islets during the priming phase of diabetes is sufficient to inhibit disease onset by promoting the expansion of intraislet CD4+CD25+ T cell pool. Approximately 40-50% of intraislet CD4+ T cells expressed the CD25 marker and exhibited characteristics of regulatory T cells including small size, high level of intracellular CTLA-4, expression of Foxp3, and transfer of protection against diabetes. Results from in vivo incorporation of BrdUrd revealed that the generation of a high frequency of regulatory T cells in the islets is due to in situ expansion upon TGF-beta expression. Thus, these findings demonstrate a previously uncharacterized mechanism by which TGF-beta inhibits autoimmune diseases via regulation of the size of the CD4+CD25+ regulatory T cell pool in vivo.

Topics: Adoptive Transfer; Animals; Base Sequence; CD4 Antigens; CD4-Positive T-Lymphocytes; Diabetes Mellitus; DNA Primers; DNA-Binding Proteins; Doxycycline; Forkhead Transcription Factors; Gene Expression Regulation; Hypoxanthine Phosphoribosyltransferase; Islets of Langerhans; Mice; Mice, Inbred NOD; Mice, SCID; Receptors, Interleukin-2; Reverse Transcriptase Polymerase Chain Reaction; T-Lymphocytes; Transforming Growth Factor beta

The aim of the study was to determine whether the expression of sulphotransferase enzymes could be affected by the presence of cytokines or peptide hormones. The effects of cytokines (TNF-alpha and TGF-beta) and insulin on sulphotransferase (SULT 1A1 and 1A3) activity were studied in a human neuronal cell line (SK-N-SH) and a human gastrointestinal tract cell line (HT-29). Cells were cultured with varying concentrations of TNF-alpha, TGF-beta or insulin for 24 h; the SULT 1A1 isoform in the 2 cell lines showed different optimal substrate concentrations. There were no direct effects of cytokines on enzyme activity. Culture with TNF-alpha increased activity of both SULT 1A1 and 1A3 in the HT-29 cells; TGF-beta also increased activities of both isoforms but to a lesser extent; insulin increased activity of SULT 1A1 only. The cytokines and insulin had relatively little effect on sulphotransferase activity in the neuronal cell line. These results suggest that, unlike neuronal cells, gastrointestinal cells may respond to physiological states by altering sulphotransferase activity. As certain substrates such as diet-derived heterocyclic amines are bioactivated by sulphation to produce carcinogenic metabolites this may be a factor in the increased incidence of colorectal cancer in patients with inflammatory bowel disease or diabetes.

Topics: Arylsulfotransferase; Cell Culture Techniques; Colon; Colorectal Neoplasms; Diabetes Mellitus; Diet; Humans; Hypoglycemic Agents; Inflammatory Bowel Diseases; Insulin; Neurons; Protein Isoforms; Sulfotransferases; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

To evaluate the plasma TGF-beta1 level in erectile dysfunction (ED) patients of various causes.. Sixty-two patients with ED and 26 potent men were subjected to the study. Based on multidisciplinary work-ups, including medical history, physical examinations, blood tests with lipid profile and hormones, penile duplex Doppler ultrasonogram and neurophysiological tests, causes for ED were classified as psychogenic (n=15), neurogenic (n=16) and vasculogenic (n=31). The plasma TGF-beta1 level was measured by the ELISA method.. The plasma TGF-beta1 level was significantly increased in the ED group (6.7+/-4.9 ng/mL), compared to the control (4.0 +/-2.1 ng/mL) (P<0.01). In the ED groups, there was a significant increase in the vasculogenic group (9.0 +/-5.5 ng/mL), compared to the psychogenic (3.8 +/-1.8 ng/mL) and neurogenic groups (4.8+/-3.2 ng/mL) (P<0.01). Of the vascular risk factors, both the smoking (7.5 +/-4.7 ng/mL) and dyslipidemia groups (7.4+/-4.4 ng/mL) showed significantly increased plasma TGF-beta1 levels, compared to the non-smokers (5.5+/-2.8 ng/mL), and those without dyslipidemia (4.8+/-2.8 ng/mL) (P<0.05).. Vascular risk factors are associated with an elevated plasma TGF-beta1 level, which may contribute to cavernous fibrosis and ED.

Topics: Adult; Aged; Arteriosclerosis; Diabetes Mellitus; Enzyme-Linked Immunosorbent Assay; Erectile Dysfunction; Female; Humans; Hyperlipidemias; Hypertension; Impotence, Vasculogenic; Male; Middle Aged; Penis; Risk Factors; Smoking; Transforming Growth Factor beta; Transforming Growth Factor beta1; Ultrasonography

Human endothelial cells were exposed to 5 mM glucose (control), 25 mM (high) glucose, or osmotic control for 72 h. TGF-beta1 production, cell growth, death, and cell cycle progression, and the effects of TGF-beta1 and TGF-beta neutralization on these parameters were studied. High glucose and hyperosmolarity increased endothelial TGF-beta1 secretion (P < 0.0001) and bioactivity (P < 0.0001). However, high glucose had a greater effect on reducing endothelial cell number (P < 0.001) and increasing cellular protein content (P < 0.001) than the osmotic control. TGF-beta antibody only reversed the antiproliferative and hypertrophic effects of high glucose. High glucose altered cell cycle progression and cyclin-dependent kinase inhibitor expression independently of hyperosmolarity. High glucose increased endothelial cell apoptosis (P < 0.01), whereas hyperosmolarity induced endothelial cell necrosis (P < 0.001). TGF-beta antibody did not reverse the apoptotic effects observed with high glucose. Exogenous TGF-beta1 mimicked the increased S phase delay but not endoreduplication observed with high glucose. High glucose altered endothelial cell growth, apoptosis, and cell cycle progression. These growth effects occurred principally via a TGF-beta1 autocrine pathway. In contrast, apoptosis and endoreduplication occurred independently of this cytokine and hyperosmolarity.

Topics: Antibodies; Apoptosis; Autocrine Communication; bcl-2-Associated X Protein; Cell Cycle; Cell Cycle Proteins; Cell Division; Cells, Cultured; Cyclin-Dependent Kinase Inhibitor p21; Cyclin-Dependent Kinase Inhibitor p27; Cyclins; Diabetes Mellitus; Endothelium, Vascular; Enzyme Inhibitors; Glucose; Humans; L-Lactate Dehydrogenase; Necrosis; Osmolar Concentration; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Transforming Growth Factor beta; Transforming Growth Factor beta1; Tumor Suppressor Proteins

Albumin excretion is modulated post-filtration by lysosomal processing that produces a spectrum of albumin-derived material in urine, much of which is not detected by conventional immunoassays. This study aimed to determine the efficacy of ramipril treatment (+ RAM) after 24 weeks on total albumin excretion (intact plus albumin-derived peptides) in spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats with (d) and without (c) diabetes.. Intact albumin excretion was analysed by radioimmunoassay and total albumin excretion was analysed by measuring radioactivity derived from circulating [ C]albumin. Renal lysosomal activity was determined by urinary [ H]dextran sulphate desulphation. Renal transforming growth factor-beta 1 (TGF-beta 1), TGF-beta inducible gene-h3 (beta ig-h3) and angiotensinogen mRNA production were analysed by real time reverse transcriptase-polymerase chain reaction.. Hypertension (SHR-c and SHR-d) resulted in a significant increase in intact albumin excretion, which was significantly reduced by ramipril treatment (P < 0.05 for SHR-c + RAM and 0.001 for SHR-d + RAM compared to non-treated). This was accompanied by a significant decrease in blood pressure (P < 0.001 for SHR-c + RAM and SHR-d + RAM), renal beta ig-h3 mRNA production (P < 0.05 for SHR-c + RAM and SHR-d + RAM), and an increase in lysosomal activity. Diabetes (WKY-d and SHR-d) primarily caused a significant increase in total albumin excretion, predominantly in the form of albumin-derived fragments in the WKY-d group and intact albumin in the SHR-d group. Ramipril treatment reduced total albumin excretion in the WKY-d + RAM group (P < 0.001).. Ramipril prevents increases in both intact albumin and total albumin excretion in hypertensive and diabetic states, respectively.

Topics: Albuminuria; Angiotensin-Converting Enzyme Inhibitors; Angiotensinogen; Animals; Blood Pressure; Diabetes Mellitus; Extracellular Matrix Proteins; Hypertension; Lysosomes; Male; Ramipril; Rats; Rats, Inbred SHR; Rats, Inbred WKY; RNA, Messenger; Transforming Growth Factor beta; Transforming Growth Factor beta1

We have shown previously that OPB-9195, a novel inhibitor of advanced glycation end products (AGE), significantly prevented renal tubular injury and tubulointerstitial fibrosis in spontaneous diabetic rats. However, the molecular mechanisms underlying this have not been fully elucidated.. Three immunochemically distinct AGE were prepared by incubating bovine serum albumin (BSA) with glucose, glyceraldehyde, or methylglyoxal. Then, the effects of AGE on human proximal tubular epithelial cells were examined. The intracellular formation of reactive oxygen species (ROS) was detected using the fluorescent probe CM-H2DCFDA. DNA synthesis was evaluated by thymidine uptake, and de novo protein synthesis was determined by [3H]leucine incorporation. Prostaglandin E2 (PGE2) and transforming growth factor-beta (TGF-beta) released into media were quantitatively analyzed in an enzyme-linked immunosorbent assay. TGF-beta gene expression was analyzed by quantitative reverse transcription-polymerase chain reaction (RT-PCR).. When these AGE-BSA were administered to tubular cells, each of them increased generation of intracellular ROS. All of the AGE-BSA, but not non-glycated BSA, were found to induce statistically significant decreases in de novo protein synthesis and PGE2 secretion by tubular cells. Furthermore, AGE-BSA up-regulated the levels of mRNAs for TGF-beta in tubular cells. The structural epitope designated glucose-derived AGE was found to have the greatest cytopathic effects on tubular cells. These AGE-induced inhibition of protein synthesis and PGE2 secretion as well as the up-regulation of TGF-beta mRNA were found to be completely prevented by N-acetylcysteine. Furthermore, H2O2 was shown to inhibit protein synthesis and PGE2 secretion by proximal tubular cells in a dose-dependent manner.. The results suggest that AGE inhibits de novo protein synthesis and stimulates TGF-beta mRNA expression in proximal tubular epithelial cells through overgeneration of intracellular ROS. Thus, AGE are involved in the pathogenesis of tubular injury in diabetic nephropathy.

Topics: Cells, Cultured; Diabetes Mellitus; Dinoprostone; Glycation End Products, Advanced; Humans; Hydrogen Peroxide; Intracellular Membranes; Kidney Tubules, Proximal; Leucine; Protein Synthesis Inhibitors; Reactive Oxygen Species; RNA, Messenger; Serum Albumin, Bovine; Thymidine; Transforming Growth Factor beta

To evaluate the biologic effect of direct cutaneous TGF-beta1 gene delivery on impaired wound healing models using genetically diabetic mice.. Diabetic mice (C57BKS.Cg-m +/+ Leprdb female mice) with 1 cm x 1 cm excisional wounds were intradermally injected with 60 microg of plasmid DNA encoding TGF-beta1 gene. The wound closure was measured up to 14 days postwounding. At days 7 and 14 postwounding, sections of skin were taken for hematoxylin and eosin and Masson's trichome staining to examine the morphology and collagen deposition. The cell proliferation and TGF-beta1 gene expression were studied using immunohistochemical stainings for 5-bromo-2-deoxyuridine and for TGF-beta1.. A higher cell proliferation rate and a denser and more organized new extracellular matrix were observed in the treated wound site. Complete wound closure was detected as early as 7 days for TGF-beta1-treated group in comparison with 11-14 days for the untreated, control plasmid DNA- and PBS-treated groups.. A single intradermal injection of TGF-beta1 plasmid DNA was sufficient to enhance wound healing. This approach represents a new strategy that may be applied to the treatment of excisional wounds in human diabetic patients.

Topics: Animals; Cell Division; Diabetes Mellitus; DNA; Extracellular Matrix; Female; Genetic Therapy; Humans; Injections, Intradermal; Mice; Mice, Inbred Strains; Recombinant Proteins; Transforming Growth Factor beta; Transforming Growth Factor beta1; Wound Healing

Dietary antigens are candidate environmental factors in the pathogenesis of type 1 diabetes. In the non-obese diabetic (NOD) mouse, an animal model of type 1 diabetes, cereal-based diets promote disease development, whereas the diets based on hydrolysed proteins or non-diabetogenic proteins are protective. The hypothesis that diabetogenic diets modulate the cytokine balance in the gut was tested. NOD mice were fed with NTP-2000 (mainly a wheat-based milk-free diet) or Prosobee (a semi-purified hypoallergenic diet based on soy protein isolate) or Prosobee plus casein (milk protein fraction). The mRNA levels of IFN-gamma, IL-10, TNF-alpha, TGF-beta, and inducible NO synthase in the small intestine and the Peyer's patches were determined by semi-quantitative RT-PCR. Mice fed on the cereal-based NTP-2000 diet expressed higher levels of the Th1-type and pro-inflammatory markers IFN-gamma, TNF-alpha, and inducible NO synthase mRNA compared to the Prosobee-fed animals. The expression of the counterregulatory cytokines IL-10 and TGF-beta was unaffected. This resulted in a significant bias of the intestinal cytokine balance towards T helper cell type 1 after feeding NTP-2000. The cytokine mRNA levels in the gut-associated Peyer's patches were not affected. Thus, modulation of gut immunoreactivity by diet may contribute to disease development in NOD mice.

Topics: Animal Feed; Animals; Caseins; Cytokines; Diabetes Mellitus; Diet, Diabetic; DNA, Complementary; Edible Grain; Female; Gastrointestinal Tract; Interferon-gamma; Interleukin-10; Mice; Mice, Inbred NOD; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Peyer's Patches; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Th1 Cells; Transforming Growth Factor beta; Triticum; Tumor Necrosis Factor-alpha

To accelerate diabetic wound healing with TGF-beta1 gene delivery system using a thermosensitive hydrogel made of a triblock copolymer, PEG-PLGA-PEG.. Two 7 x 7 mm full thickness excisional wounds were created in parallel at the back of each genetically diabetic mouse. The hydrogel containing plasmid TGF-beta1 was administered to the wound and formed an adhesive film in situ. Controls were either untreated or treated with the hydrogel without DNA. We used a commercial wound dressing, Humatrix, either with or without DNA, to compare the therapeutic effect with the thermosensitive hydrogel.. We found that thermosensitive hydrogel alone is slightly beneficial for reepithealization at early stage of healing (day 1-5), but significantly accelerated repithelializaion, increased cell proliferation, and organized collagen were observed in the wound bed treated with thermosensitive hydrogel containing plasmid TGF-beta1. The accelerated reepithelialization was accompanied with enhanced collagen synthesis and more organized extracellular matrix deposition. Humatrix alone or with plasmid TGF-beta1, had little effect.. Thermosensitive hydrogel made of PEG-PLGA-PEG triblock copolymer provides excellent wound dressing activity and delivers plasmid TGF-beta1 to promote wound healing in a diabetic mouse model.

Topics: Animals; Antimetabolites; Bromodeoxyuridine; Cell Division; Diabetes Complications; Diabetes Mellitus; DNA; Female; Gene Transfer Techniques; Hot Temperature; Humans; Hydrogels; Insulin; Lactic Acid; Mice; Mice, Inbred C57BL; Mice, Obese; Pharmaceutical Vehicles; Plasmids; Polyethylene Glycols; Polyglycolic Acid; Polylactic Acid-Polyglycolic Acid Copolymer; Polymers; Recombinant Proteins; Skin; Transforming Growth Factor beta; Wound Healing

We investigated the long term effects of Sopungsungi-won (SP), a Korean traditional formula used for senile constipation and diabetes mellitus, on the development of diabetic nephropathy (DN) in Zucker diabetic fatty (ZDF) rats. ZDF rats were fed regular laboratory chow mixed with SP or rosiglitazone (RSG) for an 8-week period. Kidney hypertrophy was developed with increasing plasma glucose level, and glomerular hypertrophy was improved by 22% and 45% in SP- and RSG-treated rats, respectively. Urinary glucose and albumin excretions were also significantly lower in SP-treated rats than in ZDF control rats. Activation of the mitogen-activated protein kinase (MAPK)-transforming growth factor beta1 (TGF beta1)-fibronectin pathway in kidney, responsible for glomerular dysfunction, was markedly blunted by SP treatment in a dose dependent manner. Our findings, for the first time, provide strong evidence that long-term administration of SP formula prevents the development and progression of DN in ZDF rats. Human trials are needed to confirm these experimental results.

Topics: Animals; Diabetes Mellitus; Diabetic Nephropathies; Drug Administration Schedule; Hypertrophy; Kidney; Male; Medicine, East Asian Traditional; Mitogen-Activated Protein Kinases; Phytotherapy; Plants, Medicinal; Rats; Rats, Zucker; Transforming Growth Factor beta; Transforming Growth Factor beta1

Recently established Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a model of naturally occurring obesity diabetes, exhibit progressive accumulation of connective tissue in the pancreas. The present study was designed to determine the pathogenic role of transforming growth factor-beta1 (TGF-beta1) in the development of pancreatic fibrosis in OLETF rats by investigating the serial changes in the expression of TGF-beta1 and extracellular matrix (ECM) in the pancreas. Progressive proliferation of connective tissue arose from the interstitial region surrounding islets at 20 wk of age and extended to the exocrine pancreas adjacent to the islets. TGF-beta1 mRNA levels in the pancreas increased at 20 wk of age and reached a peak value at 30 wk of age. Fibronectin (FN) and procollagen types I and III mRNAs peaked at 20 wk of age and remained at higher levels than those in the nondiabetic counterparts Long-Evans Tokushima Otsuka rats until 50 wk of age. Immunoreactivities for TGF-beta1 and FN were found in islets of OLETF rats at 20 wk of age and were seen in acinar and interstitial cells at 50 wk of age. Moreover, alpha-smooth muscle actin was located at interstitial region surrounding the islets. Proliferation of the connective tissue in the pancreas of OLETF rats closely correlated with expression of TGF-beta1 and ECM. Our results suggest that the development of pancreatic fibrosis in OLETF rats extends from endocrine to exocrine pancreas and that TGF-beta1 is involved in pancreatic fibrosis of OLETF rats.

Topics: Actins; Aging; Animals; Blotting, Northern; Collagen Type I; Collagen Type III; Connective Tissue; Diabetes Complications; Diabetes Mellitus; Extracellular Matrix; Fibronectins; Fibrosis; Immunohistochemistry; Islets of Langerhans; Male; Obesity; Pancreas; Rats; Rats, Inbred OLETF; RNA, Messenger; Transforming Growth Factor beta; Transforming Growth Factor beta1

We found that peroxisome proliferator-activated receptor-gamma (PPARgamma) mRNA was reduced by 77% in glomeruli of diabetic mice. Because mesangial cells play an important role in diabetic nephropathy, we examined regulation of type I collagen expression by PPARgamma and transforming growth factor-beta(1) (TGF-beta(1)) in mouse mesangial cells in the presence of 6 and 25 mM glucose. Mesangial cells contained functionally active PPARgamma. Exposure to 25 mM glucose resulted in reduced PPARgamma expression and transcriptional activity, accompanied by increased type I collagen expression. Restoration of PPARgamma activity to normal levels in cells cultured in 25 mM glucose, by transfection with a PPARgamma expression construct and treatment with the PPARgamma agonist troglitazone, returned type I collagen levels toward normal values. Activation of PPARgamma by troglitazone also decreased type I collagen mRNA and blocked TGF-beta(1)-mediated upregulation of type I collagen mRNA and protein. Moreover, PPARgamma activation suppressed basal and activated TGF-beta(1) responses in mesangial cells. This action was blocked by transfection of cells with a dominant-negative PPARgamma construct. In summary, PPARgamma suppresses the increased type I collagen mRNA and protein expression mediated by TGF-beta(1) in mesangial cells.

Topics: Animals; Biotransformation; Collagen Type I; Diabetes Mellitus; Enzyme-Linked Immunosorbent Assay; Glomerular Mesangium; Glucose; Mice; Mice, Inbred C57BL; Receptors, Cytoplasmic and Nuclear; Reverse Transcriptase Polymerase Chain Reaction; Transcription Factors; Transforming Growth Factor beta; Up-Regulation

The roles of transforming growth factor (TGF)-beta 1 in vascular proliferation, atherosclerosis, and plaque still remain controversial. TGF-beta 1 has been previously reported to inhibit the proliferation and migration of vascular smooth muscle cells and endothelial cells, in vitro. On the other hand, administration or transgenic overexpression of TGF-beta 1 enhances extracellular matrix synthesis and cellular hyperplasia of the intima and media in the normal artery and injured artery in vivo. We evaluated the correlation of arterial proliferation with plasma levels of TGF-beta 1 and TGF-beta receptor type II, respectively, in Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a new strain of spontaneous non-insulin-dependent diabetes mellitus (NIDDM) models. OLETF rats (n=30) were divided into three groups aged 5,15, and 30 weeks. Long-Evans Tokushima Otsuka (LETO) rats (n=30) were used as age-matched non-diabetic controls. Plasma TGF-beta1 and insulin were determined by enzyme-linked immunosorbent assay. Immunoreactive TGF-beta receptor type II antigen was detected by immunohistochemistry on the thoracic artery. Arterial media area was measured microscopically. Oral glucose tolerance test was performed to examine the stage of diabetes mellitus. The thoracic aorta wall section area increased significantly from the age of 15 weeks in OLETF rats, versus LETO rats. In both OLETF and LETO rats, plasma TGF-beta 1 increased significantly from the age of 15 weeks. In OLETF rats, plasma TGF-beta 1 increased significantly over that in LETO rats (P<0.001). Furthermore, TGF-beta receptor type II was detected on aortic wall as strong signals in OLETF rats, but only weakly in LETO rats. OLETF rats showed hyperinsulinemia and insulin resistance from the age of 15 weeks. With oral glucose tolerance test, from the age of 15 weeks, the high glucose level in OLETF rats was prolonged to 2 h after loading, and the insulin levels at both fasting and after loading were significantly higher than those of LETO rats (P<0.001). There are significant linear relations between plasma TGF-beta 1 antigen and aorta wall section area, and plasma TGF-beta 1 antigen and fasting insulin level (P<0.001, respectively). We found that plasma TGF-beta 1 and vascular TGF-beta type II receptors existed to a greater extent in pre- and early stages of diabetes mellitus (DM) in OLETF rats compared with LETO rats. The greater extent of each in OLETF rats was associated with hyperinsulinemia and/or vascu

Topics: Aging; Animals; Aorta, Thoracic; Blood Pressure; Body Weight; Cholesterol; Diabetes Mellitus; Disease Models, Animal; Endothelium, Vascular; Glucose Tolerance Test; Immunohistochemistry; Insulin; Male; Muscle, Smooth, Vascular; Protein Serine-Threonine Kinases; Rats; Rats, Inbred OLETF; Rats, Long-Evans; Receptor, Transforming Growth Factor-beta Type II; Receptors, Transforming Growth Factor beta; Time Factors; Transforming Growth Factor beta; Transforming Growth Factor beta1

Glycated albumin has been causally linked to the pathobiology of diabetic renal disease through its ability to stimulate the expression of transforming growth factor-beta1 (TGF-beta1), activate protein kinase C (PKC) and extracellular signal-regulated kinase (ERK), and promote production of extracellular matrix proteins in cultured glomerular cells. Whether glycated albumin modulates glomerular TGF-beta1 expression in vivo is not known. To address this issue, we assessed glomerular TGF-beta1 expression and pathology in response to reducing the burden of glycated albumin in vivo.. We measured serum glycated albumin, urine protein, glomerular TGF-beta1 expression and morphometry, and collagen IV and fibronectin mRNA in db/m and db/db controls and in db/db mice treated for eight weeks with a synthetic compound that inhibits the condensation of glucose with albumin.. In situ hybridization studies showed markedly increased glomerular TGF-beta1 mRNA in control db/db mice, which was significantly reduced in db/db mice treated for eight weeks with test compound. The treatment protocol, which normalized serum glycated albumin, concomitantly reduced the elevated protein excretion and the renal overexpression of mRNAs encoding fibronectin and collagen IV, and significantly decreased the mesangial matrix expansion, observed in db/db control animals.. These findings, to our knowledge, provide the first evidence that glomerular overexpression of TGF-beta1 in diabetes derives at least in part from elevated glycated albumin concentrations, and can be partially suppressed by inhibiting the formation of this glycated protein. The results further suggest that glycated albumin has an important nephropathogenic role in diabetes that is operative, and can be therapeutically addressed, independent of glycemic status.

Topics: Albuminuria; Aniline Compounds; Animals; Diabetes Mellitus; Diclofenac; Extracellular Matrix Proteins; Glycated Serum Albumin; Glycation End Products, Advanced; Kidney Glomerulus; Male; Mice; Mice, Mutant Strains; Phenylacetates; Serum Albumin; Transforming Growth Factor beta; Transforming Growth Factor beta1

Serum leptin levels correlate with fat cell mass and are elevated in patients with massive obesity and type 2 diabetes mellitus, which are strong risk factors for the development of glomerulosclerosis. We have previously shown in cultured glomerular endothelial cells that leptin stimulates cellular proliferation and expression of the prosclerotic cytokine transforming growth factor-beta1 (TGF-beta1). Although the effect of leptin on the hypothalamus to regulate energy homeostasis is well known, the effect of leptin on the kidney, and specifically on the glomerular mesangial cell, is unclear.. The obese, diabetic db/db mouse, which lacks the functional full-length Ob-Rb leptin receptor, is a suitable model to assess the effects of hyperleptinemia on peripheral tissues that express other receptor isoforms. The effects of leptin on glucose uptake, the TGF-beta system, and type I collagen production were evaluated in db/db mouse mesangial cells in culture. A phosphatidylinositol-3 kinase (PI-3K) inhibitor was used to assess the role of PI-3K in mediating the effects of leptin.. A short form of the leptin receptor (Ob-Ra), but not Ob-Rb, was present by reverse transcription-polymerase chain reaction in the kidney and mesangial cells of both nondiabetic db/m and diabetic db/db mice. In db/db mesangial cells, leptin increased 2-deoxy-D-glucose (2DOG) uptake dose dependently and stimulated gene expression of TGF-beta type II receptor (TbetaRII) and alpha1(I) collagen, but not TGF-beta1. Protein production of type I collagen (enzyme-linked immunosorbent assay) was also increased by leptin. Both leptin-stimulated 2DOG uptake and type I collagen production were suppressed by a PI-3K inhibitor, LY294002. Mesangial cells pretreated with leptin exhibited increased responsiveness to exogenous TGF-beta1, as evidenced by a greater production of type I collagen protein in leptin-pretreated cells exposed to low-dose TGF-beta1 (0.5 ng/mL). The addition of both TGF-beta1 (2 ng/mL) and leptin (100 ng/mL) increased type I collagen production more than addition of either TGF-beta1 or leptin alone.. Leptin increases glucose uptake and type I collagen in db/db mesangial cells through a PI-3K-dependent pathway. We postulate that increased leptin levels may transmit a signal through the short-form leptin receptor to up-regulate TbetaRII and activate the intraglomerular TGF-beta system, which may contribute to the glomerulosclerosis of obesity or type 2 diabetes.

Topics: Animals; Cells, Cultured; Collagen; Diabetes Mellitus; Glomerular Mesangium; Glucose; Leptin; Mice; Protein Isoforms; Protein Serine-Threonine Kinases; Receptor, Transforming Growth Factor-beta Type II; Receptors, Leptin; Receptors, Transforming Growth Factor beta; RNA, Messenger; Transforming Growth Factor beta; Transforming Growth Factor beta1

Expansion of extracellular matrix with fibrosis occurs in many tissues as part of the end-organ complications in diabetes, and advanced glycosylation end products (AGE) are implicated as one causative factor in diabetic tissue fibrosis. Connective tissue growth factor (CTGF), also known as insulin-like growth factor-binding protein-related protein-2 (IGFBP-rP2), is a potent inducer of extracellular matrix synthesis and angiogenesis and is increased in tissues from rodent models of diabetes. The aim of this study was to determine whether CTGF is up-regulated by AGE in vitro and to explore the cellular mechanisms involved. AGE treatment of primary cultures of nonfetal human dermal fibroblasts in confluent monolayer increased CTGF steady state messenger RNA (mRNA) levels in a time- and dose-dependent manner. In contrast, mRNAs for other IGFBP superfamily members, IGFBP-rP1 (mac 25) and IGFBP-3, were not up-regulated by AGE. The effect of the AGE BSA reagent on CTGF mRNA was due to nonenzymatic glycosylation of BSA and, using neutralizing antisera to AGE and to the receptor for AGE, termed RAGE, was seen to be due to late products of nonenzymatic glycosylation and was partly mediated by RAGE. Reactive oxygen species as well as endogenous transforming growth factor-beta1 could not explain the AGE effect on CTGF mRNA. AGE also increased CTGF protein in the conditioned medium and cell-associated CTGF. Thus, AGE up-regulates the profibrotic and proangiogenic protein CTGF (IGFBP-rP2), a finding that may have significance in the development of diabetic complications.

Topics: Cells, Cultured; Connective Tissue Growth Factor; Diabetes Mellitus; Extracellular Matrix; Fibroblasts; Glycation End Products, Advanced; Growth Substances; Humans; Immediate-Early Proteins; Intercellular Signaling Peptides and Proteins; Receptor for Advanced Glycation End Products; Receptors, Immunologic; RNA, Messenger; Transforming Growth Factor beta; Up-Regulation

Expression of angiogenic factors such as VEGF under conditions of hypoxia or other kinds of cell stress contributes to neovascularization during wound healing. The inducible endoplasmic reticulum chaperone oxygen-regulated protein 150 (ORP150) is expressed in human wounds along with VEGF. Colocalization of these two molecules was observed in macrophages in the neovasculature, suggesting a role of ORP150 in the promotion of angiogenesis. Local administration of ORP150 sense adenovirus to wounds of diabetic mice, a treatment that efficiently targeted this gene product to the macrophages of wound beds, increased VEGF antigen in wounds and accelerated repair and neovascularization. In cultured human macrophages, inhibition of ORP150 expression caused retention of VEGF antigen within the endoplasmic reticulum (ER), while overexpression of ORP150 promoted the secretion of VEGF into hypoxic culture supernatants. Taken together, these data suggest an important role for ORP150 in the setting of impaired wound repair and identify a key, inducible chaperone-like molecule in the ER. This novel facet of the angiogenic response may be amenable to therapeutic manipulation.

Topics: Adenoviridae; Animals; Cell Hypoxia; Cells, Cultured; Culture Media, Conditioned; Diabetes Complications; Diabetes Mellitus; DNA-Binding Proteins; Endoplasmic Reticulum; Endothelial Growth Factors; Endothelium, Vascular; Female; Fibroblast Growth Factor 2; Gene Expression Regulation; Genetic Therapy; Genetic Vectors; HSP70 Heat-Shock Proteins; Humans; Hypoxia-Inducible Factor 1; Hypoxia-Inducible Factor 1, alpha Subunit; Lymphokines; Macrophages; Male; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Molecular Chaperones; Neovascularization, Pathologic; Neovascularization, Physiologic; Nuclear Proteins; Oxygen; Protein Transport; Proteins; Rats; Recombinant Fusion Proteins; RNA, Antisense; RNA, Messenger; Single-Blind Method; Skin; Transcription Factors; Transforming Growth Factor beta; Transforming Growth Factor beta1; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors; Wound Healing

The purpose of this study was to identify the growth factors and cytokines present in normal and diseased corneas. Total RNA was isolated from normal and diseased corneas. cDNA was synthesized from individual corneas and semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) was performed with primers to IL-1alpha, 1IL-8, PDGF-B, BMP-2, BMP-4, IGF-I, TGF-beta2, FGF-2, and VEGF. After normalization to beta2-microglobulin, several factors were identified that were significantly different from normal. Antibodies to IGF-I, BMP-2, VEGF and TGF-beta2 were used for immunohistochemistry. A total of 93 corneas were used for this study including 31 normal, 20 keratoconus, 19 bullous keratopathy (pseudophakic and aphakic, PBK/ABK), and 23 diabetic corneas. The VEGF RNA levels were significantly decreased in the keratoconus and PBK/ABK corneas but increased in the diabetic corneas. BMP-2 gene expression was lower than normal in the PBK/ABK and diabetic corneas. IGF-I and BMP-4 RNA levels were increased in PBK/ABK. In the immunohistochemical studies, the protein patterns paralleled those found at the mRNA level. The only exception was IGF-I in diabetic corneas that showed increased staining in the epithelium and its basement membrane without a significant increase in mRNA levels. TGF-beta2 mRNA and protein levels were similar to normal in all diseased corneas. Thus, no alterations in the tested growth factors/cytokines were unique to keratoconus corneas. In contrast, PBK/ABK corneas had specific significant elevations of BMP-4 and IGF-I. Diabetic corneas were unique in their increased VEGF mRNA levels. These data suggest that while some growth factor/cytokine alterations are non-specific and can be found in multiple corneal diseases, there are others that are unique to that disease.

Topics: Adult; Aged; Bone Morphogenetic Protein 2; Bone Morphogenetic Protein 4; Bone Morphogenetic Proteins; Case-Control Studies; Corneal Diseases; Cytokines; Diabetes Complications; Diabetes Mellitus; DNA, Complementary; Endothelial Growth Factors; Fibroblast Growth Factors; Gene Expression; Growth Substances; Humans; Insulin-Like Growth Factor I; Interleukin-1; Interleukin-8; Keratoconus; Platelet-Derived Growth Factor; Reverse Transcriptase Polymerase Chain Reaction; RNA; Transforming Growth Factor beta

Topics: Adult; Biomarkers; Creatinine; Diabetes Mellitus; Diabetic Nephropathies; Female; Humans; Kidney Failure, Chronic; Male; Middle Aged; Reference Values; Transforming Growth Factor beta

Recently, we found abnormal accumulation of several extracellular matrix components in retinal basement membranes in human diabetic retinopathy (DR). Others have described increased levels of various growth factors within the vitreous of DR patients. This study examined mRNA levels of these extracellular matrix components and growth factors within human retinal tissues.. Total retinal RNA was analyzed by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). RT-PCR products were identified by Southern blotting. Samples were normalized with respect to beta2-microglobulin cDNA. Twenty-one retinas were analyzed: 6 normal, 7 diabetic without DR and 8 diabetic with DR.. In diabetic retinas without DR, the expression levels of most genes were similar to normal. In DR retinas, tenascin-C mRNA expression increased compared to both normal and diabetics without DR. By RT-PCR and Northern blotting, mainly small tenascin-C mRNA isoforms were expressed, and some of them were elevated in DR retinas. Fibronectin mRNA was elevated in DR compared to normal retinas, possibly due to the overexpression of extradomain A-containing isoform (ED-A+, or cellular fibronectin). In DR retinas, gene expression of vascular endothelial growth factor and placenta growth factor was elevated compared to normal, although mRNA for these growth factors receptors (VEGFR-1/Flt-1 and VEGFR-2/KDR) did not change significantly. Transforming growth factor-beta1 mRNA also increased in DR retinas.. The data suggest that proliferative DR development may be associated with increased retinal expression of vascular endothelial growth factor, placenta growth factor and transforming growth factor-beta1 that possibly triggers the deposition of small tenascin-C isoforms in the blood vessel walls. Angiogenesis-stimulating tenascin-C may further promote diabetic retinal neovascularization.

Topics: Aged; Aged, 80 and over; Basement Membrane; Diabetes Mellitus; Diabetic Retinopathy; Endothelial Growth Factors; Extracellular Matrix Proteins; Female; Fibronectins; Gene Expression; Growth Substances; Humans; Lymphokines; Male; Middle Aged; Placenta Growth Factor; Pregnancy Proteins; Reference Values; RNA, Messenger; Tenascin; Transforming Growth Factor beta; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

Topics: Animals; Diabetes Complications; Diabetes Mellitus; Diabetic Nephropathies; Diabetic Retinopathy; Glycation End Products, Advanced; Humans; Mice; Mice, Inbred NOD; Rats; Rats, Inbred BB; Transforming Growth Factor beta

Elevated plasma concentrations of low density lipoprotein (LDL) and very-low density lipoprotein (VLDL) have been correlated with the development of atherosclerosis. These lipoproteins may promote atherogenesis by direct deposition of lipid in the vessel wall. In addition, previous data suggested that there was an inverse correlation between serum LDL-cholesterol concentration and the proportion of transforming growth factor beta (TGF-beta) in an active form (Grainger et al. 1995. Nature Med. 1:74). Here we have investigated whether lipoproteins can affect the activity of TGF-beta1 in plasma and show that TGF-beta can associate with the lipoprotein fraction. In the plasma of healthy males, 16 +/- 5% (mean +/- standard deviation; n = 57) of the total plasma TGF-beta1 was associated with the lipoprotein fraction, with the major proportion (64 +/- 15%) in the HDL-3 subfraction. However, in ten diabetic subjects with moderately poor glucose control (Hb alc > 8.0), the proportion of total plasma TGF-beta in the lipoprotein fraction was 68 +/- 21%. This large increase in TGF-beta1 associated with the lipoprotein fraction was mainly due to association with VLDL, chylomicrons, and LDL. The lipoprotein fraction inhibits TGF-beta1 binding to the type II TGF-beta receptor extracellular domain in an ELISA and inhibits TGF-beta1 activity in the mink lung cell bioassay. We propose that sequestration of TGF-beta into lipoproteins represents a novel mechanism by which TGF-beta activity in circulation may be regulated. Lipoprotein sequestration of TGF-beta may therefore contribute to the severe depression of TGF-beta activity in advanced atherosclerosis.

Topics: Adult; Aged; Animals; Cell Division; Cell Line; Cholesterol, LDL; Chromatography, Gel; Chylomicrons; Diabetes Mellitus; Enzyme-Linked Immunosorbent Assay; Humans; Lipoproteins; Lipoproteins, HDL; Lipoproteins, LDL; Lipoproteins, VLDL; Male; Middle Aged; Mink; Protein Serine-Threonine Kinases; Receptor, Transforming Growth Factor-beta Type II; Receptors, Transforming Growth Factor beta; Recombinant Proteins; Transforming Growth Factor beta

Evidence in this paper indicates that insulin can down-regulate the inducible nitric oxide synthase (iNOS) pathway in vivo. The iNOS pathway is up-regulated in diabetes-prone rats and mice and is associated with an autoimmune process. However, the results presented here indicate that macrophage nitric oxide (NO) production and iNOS mRNA expression are also elevated in rats or mice made diabetic by streptozotocin injection in which there is no primary autoimmune component. Insulin administration reduces NO production in autoimmune-prone and streptozotocin-induced diabetic rodents. Finally, insulin decreases macrophage NO production in normal hosts. These results indicate that the autoimmune paradigm is inadequate to explain increased NO in diabetes. As a potential mechanism to explain insulin-mediated regulation of NO production, TGF-1 may be involved because 1) macrophages from diabetic mice produce less TGF-beta1 than macrophages from normal hosts; 2) the circulating TGF-beta1 level is lower in diabetic mice; and 3) insulin administration increases circulating TGF-beta1 in normal mice. Together, these results provide evidence that increased NO in diabetes is not only a cause but also an effect of beta-cell destruction and results in part from a heretofore unrecognized immunomodulatory activity of insulin.

Topics: Animals; Diabetes Mellitus; Diabetes Mellitus, Experimental; Down-Regulation; Enzyme Induction; Insulin; Macrophages; Nitric Oxide; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Rats; Rats, Inbred BB; Transforming Growth Factor beta

Transforming growth factor-beta 1 (TGF-beta 1) is a primary determinant of the mesangial expansion observed in diabetic nephropathy. In this study, we quantitated the levels of intraglomerular TGF-beta 1 mRNA in patients with diabetes mellitus using a competitive polymerase chain reaction (PCR) method. Renal biopsy specimens were obtained from 29 patients with non-insulin-dependent diabetes mellitus. Total RNA was extracted from the glomeruli and reverse transcribed into cDNA with reverse transcriptase. To prepare samples containing identical amounts of beta-actin cDNA (8 pg), we performed competitive PCR by co-amplifying mutant templates of beta-actin with a unique EcoRI site. We also used this competitive PCR method to measure TGF-beta 1 cDNA by co-amplifying mutant templates of TGF-beta 1. We observed higher expression of TGF-beta 1 mRNA in glomeruli of patients with diabetic nephropathy as compared with normal glomeruli. Intraglomerular TGF-beta 1 mRNA was elevated, even in the early stage of diabetic nephropathy. Moreover, levels of intraglomerular TGF-beta 1 mRNA correlated with values of HbA1c. These data suggest that hyperglycemia induces intraglomerular TGF-beta 1 mRNA expression in vivo, and that TGF-beta 1 overproduction may be associated with the progression of diabetic nephropathy.

Topics: Aged; Base Sequence; Biopsy; Blotting, Southern; Collagen; Diabetes Mellitus; Diabetic Neuropathies; Female; Humans; Immunohistochemistry; Kidney Glomerulus; Male; Microscopy, Confocal; Middle Aged; Molecular Sequence Data; Polymerase Chain Reaction; RNA, Messenger; Transforming Growth Factor beta

The molecular mechanisms leading to impaired immune response in less well controlled diabetic patients are unclear. In this study we have analyzed the effects of elevated glucose concentration on both DNA synthesis and the production of transforming growth factor-beta 1 (TGF-beta 1) and the interleukins (IL) IL-2, IL-6 and IL-10 in stimulated peripheral blood mononuclear cells (PBMC) obtained from normal individuals. PBMC were stimulated by pokeweed mitogen or anti-CD3-antibody which binds specifically to the CD3-surface protein of T-lymphocytes. High glucose concentrations significantly inhibited DNA synthesis in PWM- as well as anti-CD3-stimulated PBMC. Exposure to elevated glucose levels caused a significant and dose-dependent increase in the production of latent TGF-beta 1 by (PWM)-stimulated PBMC at 24 and 48 h. Production of the cytokines IL-2, IL-6 and IL-10 was suppressed by elevated glucose concentration dose- and time-dependently. In contrast to the time-dependent decreased effect of glucose-induced TGF-beta 1 production the effects of elevated glucose levels on IL-2, IL-6 and IL-10 production increased with time indicating that TGF-beta 1 production is preceding the reduced IL production. These data demonstrate for the first time that elevated glucose levels significantly alter cytokine production in stimulated peripheral mononuclear cells and concomitantly inhibit cellular proliferation. Our results indicate that high glucose-induced TGF-beta 1 production may suppress immune response by inhibiting the endogenous production of IL-2, IL-6 and IL-10.

Topics: CD3 Complex; Cell Division; Cytokines; Diabetes Mellitus; DNA; Dose-Response Relationship, Drug; Glucose; Humans; Interleukin-10; Interleukin-2; Interleukin-6; Leukocytes, Mononuclear; Transforming Growth Factor beta

Based on preliminary but variable results with direct DNA transfer into wounds, we evaluated in vivo gene transfer by particle-mediated DNA delivery to rat skin to determine whether overexpression of TGF-beta1 at the site of skin incisions would result in a significant improvement in repair. Optimization of the method with viral promoter-luciferase reporter constructs indicated that expression of luciferase activity persisted up to 5 d and was promoter, pressure, and site dependent (ventral > dorsal). Using cytomegalovirus (CMV)-driven human alpha1-antitrypsin, transgene expression was immunolocalized within keratinocytes of the stratum granulosum at 24 h. We measured tensile strength of skin incisions at 11-21 d in both normal and diabetic rats transfected with TGF-beta1 expression vectors at surgery. Native murine TGF-beta1 under an SV40 promoter produced positive effects, while wound strengthening was more pronounced in diabetic animals using a CMV-driven construct. Transfection of rat skin with constitutively active, mutant porcine TGF-beta1 under the control of the CMV and Moloney murine leukemia virus promoters significantly increased tensile strength up to 80% for 14-21 d after surgery. Transfection 24 h before surgery was more effective. Particle-mediated gene delivery can be used to deliver viral promoter-cytokine expression constructs into rat skin in a safe, efficient, and reproducible fashion. The extent of wound repair, as evidenced by enhanced tensile strength, can be markedly improved in tissues transfected with TGF-beta1 expression constructs.

Topics: alpha 1-Antitrypsin; Animals; Biolistics; Blotting, Southern; Diabetes Mellitus; DNA, Complementary; Gene Expression Regulation; Gene Transfer Techniques; Genes, Reporter; HeLa Cells; Humans; Immunohistochemistry; Keratinocytes; Polymerase Chain Reaction; Promoter Regions, Genetic; Rats; Skin; Transforming Growth Factor beta; Wound Healing