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)

Evidence suggests that increased hydrolysis and/or uptake of triglyceride-rich lipoprotein particles in skeletal muscle can be involved in insulin resistance. We determined the steady state mRNA levels of the low-density lipoprotein-related receptor (LRP) and lipoprotein lipase (LPL) in skeletal muscle of eight healthy lean control subjects, eight type 2 diabetic patients and eight nondiabetic obese individuals. The regulation by insulin of LRP and LPL mRNA expression was also investigated in biopsies taken before and at the end of a 3 h euglycemic hyperinsulinemic clamp (insulinemia of about 1 nM). LRP mRNA was expressed in human skeletal muscle (1.3+/-0.1 amol/microg total RNA in control subjects). Type 2 diabetic patients, but not nondiabetic obese subjects, were characterized by a reduced expression of LRP (0.8+/-0.2 and 1.3+/-0.3 amol/microg total RNA in diabetic and obese patients, respectively; P<0.05 in diabetic vs. control subjects). Insulin infusion decreased LRP mRNA levels in muscle of the control subjects but not in muscle of type 2 diabetic and nondiabetic obese patients. Similar results were found when investigating the regulation of the expression of LPL. Taken together, these results did not support the hypothesis that a higher capacity for clearance or hydrolysis of circulating triglycerides in skeletal muscle is present during obesity- or type 2 diabetes-associated insulin resistance.
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PMID:Expression and regulation by insulin of low-density lipoprotein receptor-related protein mRNA in human skeletal muscle. 1239 77

The subject was a 26-year-old Japanese woman of 148 cm height, 96.2 kg of body weight (BW) (body mass index (BMI) of 43.8 kg/m(2)). She was referred to our hospital on May 1, 2000 for the evaluation of marked hyperglycemia with clinical symptom of general malaise, polydipsia, and ketonuria (3+). She did not smoke, or drink alcohol. But, she tended to eat lots of sweet food every day before the onset of this symptom. Her father was diagnosed type 2 diabetes mellitus. Her fasting plasma glucose and HbA(1c), and serum C-peptide were 398 mg/dl, 7.8% and less than 0.05 ng/ml [normal range: 0.94-2.8], respectively. She tested negative for anti-glutamic acid decarboxylase (GAD) antibodies and islet-cell antibodies. C-peptide level in her urine was as low as 3.4 microg/day. We immediately started insulin treatment under the diagnosis of abrupt onset of diabetes mellitus with diabetic ketoacidosis on the day of her admission, and the insulin treatment was continued after her being discharged. She showed continuous BW reduction until her BW reached approximately 60 kg, followed by her BW being plateau. During the period, intra-abdominal visceral fat (VF) and subcutaneous fat (SF) volume assessed by helical computerized tomography (CT) showed a substantial reduction [3.9-0.5 l for VF, 19-3.2 l for SF volume]. Pre-heparin plasma lipoprotein lipase (LPL) mass showed a considerably lower value when she had continuous BW reduction than did it when her BW reduction discontinued. These findings suggest that in this subject, continuous BW reduction after the abrupt onset of diabetes is closely associated with intra-abdominal fat mass reduction, which may be related to decreased production of LPL.
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PMID:Clinical features of a young Japanese woman having marked obesity and abrupt onset of diabetes mellitus with ketoacidosis. 1241 75

This study evaluated the postprandial (PP) response to an oral fat load in 28 male patients with type 2 diabetes (mean HbA1c of 5.1%), all receiving metformin and performing physical exercise, compared with healthy subjects. The effects of micronized fenofibrate (200 mg once daily) on triglycerides (TG) and retinyl palmitate (RP) responses, lipoprotein mass concentrations, post-heparin lipase activities and coagulation factors were investigated after a 16-week double-blind, placebo-controlled period. Higher and delayed TG response after the oral fat load (P<0.001) corresponding to increases in both intestinally and endogenous TG-rich lipoproteins and lower lipoprotein lipase (LPL) activity 30 and 60 min post-heparin injection (P<0.05) were observed in the patients as compared with controls. Fasting PAI-1 activity, 6 h PP Factor VII and PAI-1 activities were higher in patients (P=0.036, P=0.032 and P=0.017, respectively). After fenofibrate treatment, TG and RP responses and peak LPL activity were no more significantly different from controls at baseline. Compared with placebo, fasting TG-rich lipoproteins and HDL(3) mass concentrations were significantly lower and higher, respectively; PP chylomicrons and very low density lipoprotein (VLDL) mass concentrations were lower; fasting and PP fibrinogen levels were significantly reduced after fenofibrate treatment. Diabetes control was unchanged throughout the study. Fenofibrate normalized the abnormal PP response and improved the fasting lipoprotein abnormalities in patients with type 2 diabetes and optimal glucose control.
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PMID:Micronized fenofibrate normalizes the enhanced lipidemic response to a fat load in patients with type 2 diabetes and optimal glucose control. 1248 62

The R219K polymorphism in the ATP-binding cassette transporter 1 gene ( ABCA1) has been associated with reduced severity of atherosclerosis, fewer coronary events, decreased triglycerides and a trend to increased HDL in men with coronary heart disease (CHD). This study examined the frequency and the effect on CHD and plasma lipids of the polymorphism in patients of both sexes attending a lipid out-patient clinic. The overall frequency of the K allele was 0.26. It was lower in patients with CHD (0.21) than in those without (0.27) but this was not statistically significant. Amongst patients with elevated Lp(a) the frequency of the K allele was significantly lower in those with CHD (0.16) than in those without (0.29). There were no statistically significant differences in total cholesterol, LDL, HDL, apoB or apoAI between carriers and non-carriers. When patients with probable secondary hypertriglyceridaemia (triglycerides >1000 mg/dl), type 2 diabetes and carriers of lipoprotein lipase polymorphisms associated with hypertriglyceridaemia were excluded, the K allele was significantly associated with reduced triglycerides but only in patients with apoE 3/3 genotype. In conclusion, we provide additional evidence that the R219K polymorphism in the ABCA1 gene either directly or as a result of linkage disequilibrium with additional functional variant(s), has a protective effect against CHD and is associated with lower plasma triglycerides in sub-groups of patients with hyperlipidaemia.
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PMID:The association of the R219K polymorphism in the ATP-binding cassette transporter 1 ( ABCA1) gene with coronary heart disease and hyperlipidaemia. 1270 Aug 93

Recent data suggest that plasma leptin may represent a cardiovascular risk factor in diabetic patients. To gain further insight into the role of leptin in atherogenesis associated with diabetes, we investigated in the present study the role of this hormone in the regulation of macrophage lipoprotein lipase (LPL), a proatherogenic cytokine overexpressed in patients with type 2 diabetes. Treatment of human macrophages with leptin (1-10 nmol/l) increased LPL expression, at both the mRNA and protein levels. Pretreatment of these cells with anti-leptin receptor (Ob-R) antibody, protein kinase C (PKC) inhibitors, calphostin C, and GF109203X, or the antioxidant N-acetylcysteine (NAC) blocked the effects of leptin. Similar results were observed in leptin-treated J774 macrophages. In these cells, leptin increased the membrane expression of conventional PKC isoforms and downregulation of endogenous PKC expression abolished the effects of leptin on macrophage LPL expression. In leptin-treated J774 cells, enhanced LPL synthetic rate and increased binding of nuclear proteins to the activated protein-1 (AP-1) consensus sequence of the LPL gene promoter were also observed. This latter effect was abrogated by GF109203X. Overall, these data demonstrate that binding of leptin at the macrophage cell surface increases, through oxidative stress- and PKC-dependent pathways, LPL expression. This effect appears to be exerted at the transcriptional level and to involve AP-1 activation.
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PMID:Leptin increases lipoprotein lipase secretion by macrophages: involvement of oxidative stress and protein kinase C. 1288 31

The epidemic increase in type 2 diabetes can be prevented only if markers of risk can be identified and used for early intervention. We examined the clinical phenotype of individuals characterized by normal or low IRS-1 protein expression in fat cells as well as the potential molecular mechanisms related to the adipose tissue. Twenty-five non-obese individuals with low or normal IRS-1 expression in subcutaneous abdominal fat cells were extensively characterized and the results compared with 71 carefully matched subjects with or without a known genetic predisposition for type 2 diabetes. In contrast to the commonly used risk marker, known heredity for diabetes, low cellular IRS-1 identified individuals who were markedly insulin resistant, had high proinsulin and insulin levels, and exhibited evidence of early atherosclerosis measured as increased intima media thickness in the carotid artery bulb. Circulating levels of adiponectin were also significantly reduced. Gene analyses of fat cells in a parallel study showed attenuated expression of several genes related to fat cell differentiation (adiponectin, aP2, PPARgamma, and lipoprotein lipase) in the group of individuals characterized by a low IRS-1 expression and insulin resistance. A low IRS-1 expression in fat cells is a marker of insulin resistance and risk for type 2 diabetes and is associated with evidence of early vascular complications. Impaired adipocyte differentiation, including low gene expression and circulating levels of adiponectin, can provide a link between the cellular marker and the in vivo phenotype.
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PMID:A novel cellular marker of insulin resistance and early atherosclerosis in humans is related to impaired fat cell differentiation and low adiponectin. 1289 Jun 97

Insulin resistance and type 2 diabetes mellitus are generally accompanied by low HDL cholesterol and high plasma triglycerides, which are major cardiovascular risk factors. This review describes abnormalities in HDL metabolism and reverse cholesterol transport, i.e. the transport of cholesterol from peripheral cells back to the liver for metabolism and biliary excretion, in insulin resistance and type 2 diabetes mellitus. Several enzymes including lipoprotein lipase (LPL), hepatic lipase (HL) and lecithin: cholesterol acyltransferase (LCAT), as well as cholesteryl ester transfer protein (CETP) and phospholipid transfer protein (PLTP), participate in HDL metabolism and remodelling. Lipoprotein lipase hydrolyses lipoprotein triglycerides, thus providing lipids for HDL formation. Hepatic lipase reduces HDL particle size by hydrolysing its triglycerides and phospholipids. A decreased postheparin plasma LPL/HL ratio is a determinant of low HDL2 cholesterol in insulin resistance. The esterification of free cholesterol by LCAT increases HDL particle size. Plasma cholesterol esterification is unaltered or increased in type 2 diabetes mellitus, probably depending on the extent of triglyceride elevation. Subsequent CETP action results in transfer of cholesteryl esters from HDL towards triglyceride-rich lipoproteins, and is involved in decreasing HDL size. An increased plasma cholesteryl ester transfer is frequently observed in insulin-resistant conditions, and is considered to be a determinant of low HDL cholesterol. Phospholipid transfer protein generates small pre beta-HDL particles that are initial acceptors of cell-derived cholesterol. Its activity in plasma is elevated in insulin resistance and type 2 diabetes mellitus in association with high plasma triglycerides and obesity. In insulin resistance, the ability of plasma to promote cellular cholesterol efflux may be maintained consequent to increases in PLTP activity and pre beta-HDL. However, cellular cholesterol efflux to diabetic plasma is probably impaired. Besides, cellular abnormalities that are in part related to impaired actions of ATP binding cassette transporter 1 and scavenger receptor class B type I are likely to result in diminished cellular cholesterol efflux in the diabetic state. Whether hepatic metabolism of HDL-derived cholesterol and subsequent hepatobiliary transport is altered in insulin resistance and type 2 diabetes mellitus is unknown. Specific CETP inhibitors have been developed that exert major HDL cholesterol-raising effects in humans and retard atherosclerosis in animals. As an increased CETP-mediated cholesteryl ester transfer represents a plausible metabolic intermediate between high triglycerides and low HDL cholesterol, studies are warranted to evaluate the effects of these agents in insulin resistance- and diabetes-associated dyslipidaemia.
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PMID:Alterations in high-density lipoprotein metabolism and reverse cholesterol transport in insulin resistance and type 2 diabetes mellitus: role of lipolytic enzymes, lecithin:cholesterol acyltransferase and lipid transfer proteins. 1463 88

Dyslipidaemia, hallmarked by low HDL cholesterol and high plasma triglycerides, is a feature of insulin resistance and type 2 diabetes mellitus. These lipoprotein abnormalities represent major cardiovascular risk factors in these conditions. Among other factors, lipoprotein lipase (LPL), hepatic lipase (HL), lecithin:cholesterol acyltransferase (LCAT) and cholesteryl ester transfer protein (CETP) play an important role in an abnormal HDL metabolism in insulin resistance and type 2 diabetes mellitus. LPL hydrolyses lipoprotein triglycerides, thus providing lipids for HDL formation. In insulin resistant states, a decreased post-heparin plasma LPL activity contributes to a low HDL cholesterol, whereas an increased activity of HL reduces HDL particle size by hydrolysing its triglycerides and phospholipids. High HL activity coincides with low HDL cholesterol. The esterification of free cholesterol by LCAT increases HDL particle size. Subsequent CETP action results in transfer of cholesteryl esters from HDL towards triglyceride-rich lipoproteins. This cholesteryl ester transfer process results in lower HDL cholesterol and indirectly decreases HDL size. Plasma cholesterol esterification is unaltered or increased, whereas cholesteryl ester transfer is enhanced in type 2 diabetes mellitus, abnormalities which are probably related to the degree of hypertriglyceridaemia. It is plausible that a low LPL activity contributes to premature atherosclerosis as observed in insulin resistance and type 2 diabetes mellitus, but the effects of high HL activity and altered plasma cholesterol esterification on atherosclerosis development are uncertain. Since the cholesteryl ester transfer process between lipoproteins provides a metabolic intermediate between low HDL cholesterol and high plasma triglycerides, hypertriglyceridaemia-associated accelerated transfer of cholesteryl ester out of HDL may be pathogenetically involved in the development of cardiovascular disease in insulin resistance and type 2 diabetes mellitus.
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PMID:Role of lipases, lecithin:cholesterol acyltransferase and cholesteryl ester transfer protein in abnormal high density lipoprotein metabolism in insulin resistance and type 2 diabetes mellitus. 1465 31

Pancreatic beta cell dysfunction is an early and crucial pathogenic factor in the development of type 2 diabetes. Free fatty acids (FFA) and adipokines released from adipose tissues lead to both the development of insulin resistance and beta cell dysfunction. Adiponectin is a novel adipokine with antidiabetic properties. Its circulating concentrations are reduced in subjects with increased visceral adiposity, insulin resistance, or type 2 diabetes. Very recently, the cloning of two adiponectin receptors AdipoR1 and AdipoR2 was reported. AdipoR1 is abundantly expressed in muscle, while AdipoR2 is predominantly expressed in liver. Here we report the marked expression of mRNAs for the adiponectin receptors AdipoR1 and AdipoR2 in human and rat pancreatic beta cells, at levels similar to liver and greater than muscle. Adiponectin receptor expression is increased by beta cell exposure to the unsaturated FFA oleate, and treatment of insulin-producing cells with globular adiponectin induces lipoprotein lipase expression. Regulated adiponectin receptor expression on pancreatic beta cells might be a novel mechanism modulating the effects of circulating adiponectin.
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PMID:Expression of adiponectin receptors in pancreatic beta cells. 1465 88

The central role of the intracellular enzyme hormone-sensitive lipase (HSL) in regulating fatty acid metabolism makes it an interesting pharmacological target for the treatment of insulin resistant and dyslipidemic disorders where a decrease in delivery of fatty acids to the circulation is desirable, e.g., in individuals with type 2 diabetes, metabolic syndrome, or impaired glucose tolerance. On the basis of a lead structure from high throughput screening, we have identified a very potent type of carbamoyl-triazole inhibitors of HSL. As part of the lead optimization program, four new classes of carbamoyl-triazoles were synthesized and tested with respect to potency, efficacy and selectivity. Methyl-phenyl-carbamoyl-triazoles were identified as potent and efficacious HSL inhibitors. These compounds do not inhibit other hydrolases such as hepatic lipase, lipoprotein lipase, pancreatic lipase, and butyrylcholine esterase. However, the inhibitors 4b and 4g with IC(50) values for HSL of 0.17 and 0.25 microM, respectively, were the only inhibitors selective against acetylcholine esterase. A reversible pseudosubstrate inhibition mechanism is proposed for this class of inhibitors.
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PMID:Synthesis and structure-activity relationship for a novel class of potent and selective carbamoyl-triazole based inhibitors of hormone sensitive lipase. 1471 11


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