Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011860 (type 2 diabetes)
 57,723 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We evaluated whether ramipril, one of long-acting ACEIs, has a direct effect on pancreas islets in animal model of type 2 diabetes. OLETF rats were treated with ramipril for 24 weeks. We assessed the body weight, glucose tolerance, and the amount of islet fibrosis. RT-PCR and Western blot analysis of transforming growth factor-beta with its downstream signals were performed from the pancreas. Ramipril treatment remarkably reduced weight gain and the area under the curve of glucose. Islet fibrosis and the expression of TGF-beta with its downstream signal molecules were significantly reduced in the pancreas of ramipril-treated group than in control and paired-feeding group. These beneficial effects of ramipril might be related to the downregulation of TGF-beta and its downstream signals in OLETF rats. To our knowledge, this is the first report suggesting the potential effect of ramipril on the prevention of islet destruction by fibrosis in the animal model of type 2 diabetes mellitus.
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PMID:Ramipril treatment suppresses islet fibrosis in Otsuka Long-Evans Tokushima fatty rats. 1500 19

Increased extracellular matrix (ECM) protein deposition and capillary basement membrane (BM) thickening are characteristic features of diabetic retinal microangiopathy. Recent observations in the authors' laboratories suggest that high glucose in endothelial cells as well as diabetes causes up-regulation of total fibronectin (FN), as well as extradomain-B (EDB) containing the spliced variant of FN, oncofetal FN, in the retina. This splice variant is normally absent in mature adult tissues and is believed to be involved in angiogenesis. In this study, the authors have investigated the role of C-peptide in the production of ECM proteins and capillary BM thickening in the retina of diabetic rats. They investigated retinas from poorly controlled diabetic BB/Wor rats with or without C-peptide treatment as well as those from age-matched nondiabetic control rats after 8 months of diabetes. In addition, the authors investigated retinas from BBDRZ/Wor rats, a model of type 2 diabetes. Following a treatment period of 8 months, retinal tissues were harvested for gene expression and histological analyses. In the retinas of diabetic BB/Wor rats, a significant increase of oncofetal FN was demonstrated compared to control rats. C-peptide treatment of BB/Wor rats completely prevented such increase. Furthermore, retinas from BBDRZ/Wor rats, did not exhibit any such alteration in oncofetal FN expression. The authors further examined retinal capillary BM thickening using ultrastructural morphometry. C-peptide treatment was ineffective in preventing the diabetes-induced increase in capillary BM thickness. The authors' previous studies of cultured endothelial cells demonstrated that oncofetal FN synthesis is, at least in part, mediated via transforming growth factor-beta (TGF-beta) and endothelin-1 (ET-1). Hence, they examined these two transcripts in the retina of these animals. Diabetes caused significant increase in mRNA expression of ET-1 and TGF-beta, which was not prevented by C-peptide treatment. Hence it appears that C-peptide is effective in preventing diabetes-induced oncofetal FN expression and that these effects are not mediated via ET-1 or TGF-beta. In conclusion, these data suggest that C-peptide is involved in regulating ECM protein composition. Furthermore, normalization of diabetes-induced oncofetal FN up-regulation may suggest importance of C-peptide in advanced alterations in diabetic retinopathy such as angiogenesis.
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PMID:C-peptide and retinal microangiopathy in diabetes. 1519 74

Obesity is the central promoter of the metabolic syndrome which also includes disturbed fibrinolysis in addition to hypertension, dyslipidaemia and impaired glucose tolerance/type 2 diabetes mellitus. Plasminogen activator inhibitor-1 (PAI-1) is the most important endogenous inhibitor of tissue plasminogen activator and uro-plasminogen activator, and is a main determinant of fibrinolytic activity. There is now compelling evidence that obesity and, in particular, an abdominal type of body fat distribution are associated with elevated PAI-1 antigen and activity levels. Recent studies established that PAI-1 is expressed in adipose tissue. The greater the fat cell size and the adipose tissue mass, the greater is the contribution of adipose production to circulating PAI-1. Experimental data show that visceral adipose tissue has a higher capacity to produce PAI-1 than subcutaneous adipose tissue. Studies in human adipocytes indicate that PAI-1 synthesis is upregulated by insulin, glucocorticoids, angiotensin II, some fatty acids and, most potently, by cytokines such as tumour necrosis factor-alpha and transforming growth factor-beta, whereas catecholamines reduce PAI-1 production. Interestingly, pharmacological agents such as thiazolidinediones, metformin and AT(1)-receptor antagonists were found to reduce adipose expression of PAI-1. In addition, weight loss by dietary restriction or comprehensive lifestyle modification is effective in lowering PAI-1 plasma levels. In conclusion, impaired fibrinolysis in obesity is probably also due to an increased expression of PAI-1 in adipose tissue. An altered function of the endocrine system and an impaired auto-/paracrine function at the fat cell levels may mediate this disturbance of the fibrinolytic system and thereby increase the risk for cardiovascular disease..
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PMID:Obesity and impaired fibrinolysis: role of adipose production of plasminogen activator inhibitor-1. 1535 68

GLUT-4 (glucose transporter) receptor, tumor necrosis factor-alpha (TNF-alpha), interleukins-6 (IL-6), daf-genes and PPARs (peroxisomal proliferation activator receptors) play a role in the development of insulin resistance syndrome and associated conditions. But, the exact interaction between these molecules/factors and the mechanism(s) by which they produce insulin resistance syndrome is not clear. I propose that a defect in the activity of the enzymes Delta6 and Delta5 desaturases that are essential for the formation of long chain metabolites of essential fatty acids, linoleic acid and alpha-linolenic acid, is a factor in the development of insulin resistance syndrome. Long chain polyunsaturated fatty acids (LCPUFAs) increase cell membrane fluidity and enhance the number of insulin receptors and the affinity of insulin to its receptors; suppress TNF-alpha, IL-6, macrophage migration inhibitory factor (MIF) and leptin synthesis; increase the number of GLUT-4 receptors, serve as endogenous ligands of PPARs, modify lipolysis, and regulate the balance between pro- and anti-oxidants, and thus, play a critical role in the pathogenesis of insulin resistance. In the nematode, Caenorhabditis elegans, the protein encoded by daf-2 is 35% identical to the human insulin receptor; daf-7 codes a transforming growth factor-beta (TGF-beta) type signal and daf-16 enhances superoxide dismutase (SOD) expression. Melatonin has anti-oxidant actions similar to daf-16, TGF-beta and SOD. Calorie restriction enhances the activity of Delta6 and Delta5 desaturases, melatonin production, decreases daf-2 signaling, free radical generation, and augments anti-oxidant defenses that may explain the beneficial effect of diet control in the management of obesity, insulin resistance, and type II diabetes mellitus. These evidences suggest that the activities of Delta6 and Delta5 enzymes play a critical role in the expression and regulation of GLUT-4, TNF-alpha, IL-6, MIF, daf-genes, melatonin, and leptin by modulating the synthesis and tissue concentrations of LCPUFAs. Caloric restriction delays ageing by activating Sir 2 deacetylase in yeast, and expression of Sir 2 (SIRT1) in human cells. Both insulin and insulin-like growth factor-1 (IGF-1) attenuated this response. SIRT1 sequesters the proapoptotic factor Bax, prevents stress-induced apoptosis of cells, and thus, prolongs survival. In addition, SIRT1 repressed PPAR-gamma, and overexpression of SIRT1 attenuated adipogenesis, and upregulation of SIRT in differentiated fat cells triggered lipolysis and loss of fat, events that are known to attenuate insulin resistance and prolong life span. It remains to be seen whether LCPUFAs have a regulatory role in SIRT1 expression and control Sir 2 deacetylase activity. Thus, calorie restriction or reduced food intake has a role not only in the pathobiology of insulin resistance, but also in other associated conditions such as obesity, type II diabetes mellitus, ageing, and longevity.
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PMID:A defect in the activity of Delta6 and Delta5 desaturases may be a factor predisposing to the development of insulin resistance syndrome. 1585 Jul 15

Diabetic kidney disease has been associated with the presence of lipid deposits, but the mechanisms for the lipid accumulation have not been fully determined. In the present study, we found that db/db mice on the FVB genetic background with loss-of-function mutation of the leptin receptor (FVB-Lepr(db) mice or FVBdb/db) develop severe diabetic nephropathy, including glomerulosclerosis, tubulointerstitial fibrosis, increased expression of type IV collagen and fibronectin, and proteinuria, which is associated with increased renal mRNA abundance of transforming growth factor-beta, plasminogen activator inhibitor-1, and vascular endothelial growth factor. Electron microscopy demonstrates increases in glomerular basement membrane thickness and foot process (podocyte) length. We found that there is a marked increase in neutral lipid deposits in glomeruli and tubules by oil red O staining and biochemical analysis for cholesterol and triglycerides. We also detected a significant increase in the renal expression of adipocyte differentiation-related protein (adipophilin), a marker of cytoplasmic lipid droplets. We examined the expression of sterol regulatory element-binding protein (SREBP)-1 and -2, transcriptional factors that play an important role in the regulation of fatty acid, triglyceride, and cholesterol synthesis. We found significant increases in SREBP-1 and -2 protein levels in nuclear extracts from the kidneys of FVBdb/db mice, with increases in the mRNA abundance of acetyl-CoA carboxylase, fatty acid synthase, and 3-hydroxy-3-methylglutaryl-CoA reductase, which mediates the increase in renal triglyceride and cholesterol content. Our results indicate that in FVBdb/db mice, renal triglyceride and cholesterol accumulation is mediated by increased activity of SREBP-1 and -2. Based on our previous results with transgenic mice overexpressing SREBP-1 in the kidney, we propose that increased expression of SREBPs plays an important role in causing renal lipid accumulation, glomerulosclerosis, tubulointerstitial fibrosis, and proteinuria in mice with type 2 diabetes.
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PMID:Regulation of renal lipid metabolism, lipid accumulation, and glomerulosclerosis in FVBdb/db mice with type 2 diabetes. 1604 98

Diabetic nephropathy is currently the most common cause of end-stage renal disease. Diabetic nephropathy patients, whether insulin dependent or not, develop fibrotic changes in glomeruli that manifest as overt nephropathy. Previously, we demonstrated that 5-chloro-2-{(1E)-3-[2-(4-methoxybenzoyl)-4-methyl-1H-pyrrol-1-yl]prop-1-en-1-yl}-N-(methylsulfonyl)benzamide (SMP-534) reduces extracellular matrix (ECM) production induced by transforming growth factor-beta (TGF-beta) in vitro and prevents the accumulation of ECM in glomeruli in rat Thy-1 nephritis models. In this study, we examined the long-term effects of SMP-534 on renal insufficiency and glomerulosclerosis in db/db mice, which are models of type 2 diabetes. A diet containing SMP-534 was given to the mice from the age of 9 to 25 wk, and blood and urine analysis were performed at 8, 17, and 25 wk. At the end of study, kidney tissues were analyzed histologically. Treatment with SMP-534 dose dependently suppressed the increase of urinary albumin and type IV collagen excretion in db/db mice. The renal histological analysis showed that SMP-534 dose dependently suppressed the increase of mesangial expansion in the kidney. In the immunohistological analysis, fibronectin and type IV collagen expression were lower in SMP-534-treated db/db mice compared with vehicle-treated db/db mice. This study suggested that SMP-534 ameliorated the increase of ECM production in kidney of db/db mice, possibly through the inhibition of TGF-beta action. Hence, antifibrotic agents such as SMP-534 might be a new therapeutic option for the treatment of diabetic nephropathy.
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PMID:SMP-534 ameliorates progression of glomerular fibrosis and urinary albumin in diabetic db/db mice. 1627 77

Genetics, oxidative stress: superoxide anion (O2*-) and hydrogen peroxide (H2O2), endothelial nitric oxide (eNO), lipid peroxides, anti-oxidants, endothelin, angiotensin converting enzyme (ACE) activity, angiotensinII, transforming growth factor-beta (TGF-beta), insulin, homocysteine, asymmetrical dimethyl arginine, proinflammatory cytokines: interleukin-6 (IL-6), tumor necrosis factor-a (TNF-alpha), C-reactive protein (hs-CRP), and long-chain polyunsaturated fatty acids (LCPUFAs), and activity of NAD(P)H oxidase have a role in human essential hypertension. There is a close interaction between endogenous molecules: eNO, endothelin, cytokines, and nutrients: folic acid, L-arginine, tetrahydrobiopterin (H4B), vitamin B6, vitamin B12, vitamin C, and LCPUFAs. Statins mediate some, if not all, of their actions through LCPUFAs, whereas these fatty acids (especially omega-3 fatty acids) suppress cyclo-oxygenase activity and the synthesis of pro-inflammatory cytokines, and activate parasympathetic nervous system, actions that reduce the risk of major vascular events. Some LCPUFAs form precursors to lipoxins and resolvins that have anti-inflammatory actions. Low-grade systemic inflammation seen in hypertension seems to have its origins in the perinatal period and availability of adequate amounts of LCPUFAs during the critical periods of brain growth prevents the development of hypertension. This indicates that preventive strategies aimed at decreasing the incidence of hypertension and its associated conditions such as atherosclerosis, type 2 diabetes, coronary heart disease (CHD), and cardiac failure in adulthood need to be instituted during the perinatal period if they are to be effective.
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PMID:Hypertension as a low-grade systemic inflammatory condition that has its origins in the perinatal period. 1671 19

Increased extracellular matrix material is a pathological hallmark of diabetic nephropathy. In addition to collagens, a variety of non-collagenous glycoproteins such as fibronectin also accumulate in the kidney of diabetics. The effect of diabetes on degradative pathways, in particular those involving non-collagenous proteins, are relatively unexplored. In this study, we determined the expression of the major matrix metalloproteinase (MMP) responsible for degrading the non-collagenous matrix glycoprotein fibronectin. Furthermore, the modulation of these MMPs by advanced glycation end products (AGE), a key factor in the diabetic milieu, was explored. Exposure of mesangial cells to AGEs led to a significant reduction in MMP-7, but not MMP-3 or -10. MMP-7 expression was normalized by both aminoguanidine, an inhibitor of glycation product formation, or by a neutralizing anti-transforming growth factor-beta (TGF-beta) antibody. In streptozotocin-induced diabetic rats, the diminution in MMP-7 expression and excessive fibronectin accumulation were attenuated by aminoguanidine. Humans with type 2 diabetes and nephropathy displayed similar alterations in MMP-7 to their rodent counterparts. Our findings suggest that diminished expression of the glycoprotein-degrading enzyme, MMP-7, may play a role in fibronectin accumulation in the diabetic kidney in response to AGEs and/or TGF-beta.
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PMID:Advanced glycation end products decrease mesangial cell MMP-7: a role in matrix accumulation in diabetic nephropathy? 1755 58

In our previous study, the polyherbal drug Hachimi-jio-gan was reported to possess a protective effect against the progression of diabetic nephropathy by attenuating glucose toxicity and renal damage with a type 2 diabetic model, Otsuka Long-Evans Tokushima Fatty (OLETF) rats. Based on these findings, this study was undertaken to reveal the effect of Hachimi-jio-gan on pancreatic damage focusing on fibrosis and oxidative stress in type 2 diabetes. OLETF rats were orally administered Hachimi-jio-gan for 32 weeks, and we assessed the changes in the serum glucose level every 8 weeks, as well as those of body weight, and food and water consumption every 4 weeks. In addition, pancreatic wet weight, insulin content, and Western blot analyses of transforming growth factor-beta(1), fibronectin, and nuclear factor-kappaB-related inflammatory enzymes, such as inducible nitric oxide synthesis and cyclooxygenase-2, were also performed in the pancreas. As a consequence, long-term treatment with Hachimi-jio-gan had a hypoglycemic effect, reducing pancreatic atrophy and fibrosis, and ameliorating the oxidative status. Therefore, this may provide evidence that Hachimi-jio-gan is a therapeutic target for preventing the development of pancreatic damage concomitant with hyperglycemia in type 2 diabetes.
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PMID:Protective effect of Hachimi-jio-gan against the development of pancreatic fibrosis and oxidative damage in Otsuka Long-Evans Tokushima Fatty rats. 1760 44

Lithospermic acid B (LAB), an active component isolated from Salvia miltiorrhizae, has been reported to have renoprotective effects in type 1 diabetic animal models. In the present study we investigated the effects of LAB on the prevention of diabetic nephropathy in type 2 diabetic Otsuka Long-Evans-Tokushima Fatty (OLETF) rats. LAB (20 mg/kg) was given orally once daily to 10-week-old male OLETF rats for 28 weeks. Treatment of OLETF rats with LAB had little effects on body weight and blood glucose levels. Treatment with LAB resulted in significant reduction in blood pressure. LAB markedly attenuated albuminuria and significantly lowered levels of lipid peroxidation, monocyte chemoattractant protein-1 (MCP-1), and transforming growth factor-beta (TGF-beta1) expression in renal tissues of OLETF rats. In addition, LAB inhibited the progression of glomerular hypertrophy, mesangial expansion, and expansion of the extracellular matrix in the renal cortex. Collectively, these results suggest that LAB has beneficial effects on the diabetic nephropathy in OLETF rats by decreasing blood pressure, oxidative stress, and MCP-1 expression. Our results suggest that LAB might be a new therapeutic agent for the prevention of nephropathy in type 2 diabetes.
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PMID:Lithospermic acid B ameliorates the development of diabetic nephropathy in OLETF rats. 1803 23


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