Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.6.1.2 (alanine aminotransferase)
 26,722 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Thiazolidinediones are a new class of drugs for the treatment of type 2 diabetes, and act by improving insulin sensitivity in adipose tissue, liver and skeletal muscle. Rosiglitazone and pioglitazone are registered for use in monotherapy, and in combination with sulfonylureas and metformin. Pioglitazone is also licensed for use in combination with insulin. There is level II evidence that in patients with inadequate glycaemic control both drugs reduce the level of HbA1c and fasting plasma glucose (FPG) when used as monotherapy and in combination with sulfonylurea or metformin or insulin; and both drugs increase levels of HDL and LDL and lower free fatty acid levels, but only pioglitazone significantly lowers triglyceride levels. Both drugs lower fasting insulin and C-peptide levels. In monotherapy, they may be slightly less potent at reducing the level of HbA1c than sulfonylureas or metformin. The maximal effect of these agents may not be seen for 6-14 weeks after commencement. Both drugs are well tolerated but liver function must be checked at baseline every second month for the first year, and periodically thereafter. The drugs are currently contraindicated in patients with moderate to severe liver dysfunction and alanine aminotransferase levels more than 2.5 times normal, New York Heart Association III-IV cardiac status, pregnancy, lactation and in children. The main side effects include weight gain, oedema, and mild dilutional anaemia.
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PMID:Thiazolidinediones and type 2 diabetes: new drugs for an old disease. 1204 35

Troglitazone (TRZ) is the first of a new group of oral antidiabetic drugs, the thiazolidinediones, and is proven to lower plasma glucose levels in patients with type 2 diabetes mellitus. However, the concern has been raised because of several reports, in which severe hepatic dysfunction leading to hepatic failure was demonstrated in a few patients receiving the drug. We studied the effects of TRZ on the hepatotoxicity of carbon tetrachloride (CCl(4)) and acetaminophen (APAP) in rats, both of which exert their toxic effects through bioactivation associated with cytochrome P450 3A (CYP3A) and 2E1 (CYP2E1). Male standard (Wistar/ST) and type 2 diabetic model (GK/Jal) rats were kept on a powdered chow diet containing 0, 100, 500 mg/kg/rat of TRZ. Three weeks later, the rats were either sacrificed for an in vitro metabolism study or challenged with 0.50 g/kg CCl(4) p.o. or 0.75 g/kg APAP i.p.TRZ at 100 and 500 mg/kg/rat increased the CYP3A level as well as the testosterone 6beta-hydroxylation activities in liver microsomes, but did not affect CYP2E1. TRZ also enhanced APAP hepatotoxicity, as evidenced by significantly increased levels of alanine aminotransferase, aspartate aminotransferase and alpha-glutathione S-transferase in the plasma of rats, and by significantly low hepatic glutathione concentration. Our study demonstrated that high doses of TRZ can enhance hepatotoxicity of APAP in Wistar/ST and GK/Jal by inducing hepatic CYP3A.
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PMID:Troglitazone enhances the hepatotoxicity of acetaminophen by inducing CYP3A in rats. 1206 33

The glycaemic and lipid effects of treatment with pioglitazone in combination with a stable insulin regimen were evaluated in patients with type 2 diabetes. Patients (n=566) receiving stable insulin regimens for > or = 30 days yet who had HbA1c > or = 8.0% and C-peptide > 0.7 microg/l were randomised to receive once-daily 15 mg pioglitazone, 30 mg pioglitazone, or placebo in a 16-week multicentre, double-blind, placebo-controlled trial. Per study protocol, the insulin dose was to remain unchanged, but could be decreased in response to hypoglycaemia. At the end of double-blind treatment, patients receiving pioglitazone (15 mg or 30 mg) showed statistically significant mean decreases relative to baseline HbA1c (-1.0 and -1.3, respectively; p<0.0001) and fasting plasma glucose (FPG) (-34.5 mg/dl [-1.92 mmol/l] and -48.0 mg/dl [-2.67 mmol/l], respectively; p<0.0001); these differences compared with placebo were also significant (p<0.0001). Pioglitazone (15 or 30 mg) yielded significant increases in HDL-C levels (mean increases ranging from +7.1% to + 9.3%) compared with baseline or placebo (p<0.01). The 30 mg dose also significantly reduced mean triglyceride levels (-23.7%) compared with placebo (p=0.0218). No consistent changes in TC or LDL-C levels were observed. The incidence of adverse events was similar in all treatment groups, although the incidences of weight increase, hypoglycaemia and oedema were higher among patients receiving insulin plus pioglitazone. There was no evidence of hepatotoxicity or drug-induced elevations of serum ALT > or = 3 x ULN. Pioglitazone, when added to stable insulin regimens, significantly improved HbA1c and FPG in type 2 diabetes. Pioglitazone treatment also provided significant benefit with respect to plasma HDL-C and triglyceride levels. Whether these lipid changes have an impact on overall diabetic complications remains to be determined.
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PMID:Efficacy and safety of pioglitazone in type 2 diabetes: a randomised, placebo-controlled study in patients receiving stable insulin therapy. 1207 6

Nonalcoholic steatohepatitis (NASH) is a disorder characterized by hepatic steatosis, inflammation, and fibrosis. Leptin is an adipocyte-derived antiobesity hormone that in rodents prevents "lipotoxicity" by limiting triglyceride accumulation and also regulates matrix deposition (fibrosis) during wound healing. We therefore determined serum leptin levels in patients with NASH to determine whether relationships existed between leptin levels and severity of hepatic steatosis or fibrosis. We used a radioimmunoassay to determine serum [total] leptin concentrations in 27 men and 20 women with NASH and 47 controls matched for gender and body mass index (BMI; and partly for age). Serum leptin values were correlated with hepatic steatosis, fibrosis, and inflammation (each categorized semiquantitatively on liver histology), and with anthropometric indices, serum lipids, glucose, insulin, c-peptide, and alanine aminotransferase (ALT) levels. Compared with the controls, mean serum leptin levels were raised in both men and women with NASH (men 14 +/- 11 ng/mL vs. 7.2 +/- 4.1 ng/mL, P =.003; women 35 +/- 16 ng/mL vs. 15 +/- 8.2 ng/mL, P <.001). Leptin values correlated with serum c-peptide levels but not with BMI. In a multivariate analysis, serum leptin (P =.027), serum c-peptide (P =.001), and age (P =.027) were selected as independent predictors of the severity of hepatic steatosis. However, serum leptin was not an independent predictor of hepatic inflammation or fibrotic severity. In conclusion, hyperleptinemia occurs in NASH and is not explained simply by gender, obesity, or the presence of type 2 diabetes. Furthermore, leptin levels correlate directly with the severity of hepatic steatosis but not with inflammation or fibrosis. We propose that the relationship between leptin and steatosis reflects a pathogenic role of leptin in hepatic insulin resistance and/or a failure of the antisteatotic actions of leptin ("peripheral leptin resistance").
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PMID:Serum leptin in NASH correlates with hepatic steatosis but not fibrosis: a manifestation of lipotoxicity? 1214 49

Insulin resistant metabolic syndrome is a major clinical disorder including hyperlipidaemia, hypertension, impaired glucose tolerance and/or type 2 diabetes and central obesity, which are well established cardiovascular risk factors. We report the case of a 61-year-old woman who developed severe hypercholesterolaemia and hypertriglyceridaemia after liver transplantation. In her forties she had hypertension, mixed hyperlipidaemia, mild hyperglycaemia and moderate abdominal obesity, suggesting the presence of the metabolic syndrome. She had liver enzyme elevation and severe steatosis and hepatomegaly at ultrasonography. At age 52, cryptogenic liver cirrhosis was diagnosed and rapidly progressing liver failure developed. In 1992 she underwent liver transplantation. Seven years after transplant the patient had abdominal obesity, high blood pressure, marked hypercholesterolaemia, hypertriglyceridaemia and moderate elevation of alanine aminotransferase. She also had impaired glucose tolerance and markedly increased basal and post-glucose load plasma insulin levels. Steatohepatitis was demonstrated by serial liver biopsies. This is the first case that reports the recurrence of the metabolic syndrome following liver transplantation. We postulate that metabolic syndrome may have promoted fatty liver and subsequent progression to end stage liver disease. We also stress the need for careful management of the metabolic syndrome in order to decrease the long-term risk for cardiovascular disease.
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PMID:Recurrence of insulin resistant metabolic syndrome following liver transplantation. 1254 3

Chronic liver disease is a major cause of morbidity and mortality in the United States. Although often used to detect liver disease, the prevalence and etiology of elevated aminotransferases are unknown. We analyzed data on adults ages 17 yr and older (N = 15,676) from the Third National Health and Nutrition Examination Survey (1988-1994). Participants were classified as having elevated aminotransferase levels if either aspartate aminotransferase or alanine aminotransferase was elevated above normal. Aminotransferase elevation was classified as "explained" if there was laboratory evidence of hepatitis B or C infection, iron overload, or if there was a history of alcohol consumption. Analyses were weighted to provide national estimates. The prevalence of aminotransferase elevation in the United States was 7.9%. Aminotransferase elevation was more common in men compared to women (9.3% vs 6.6%, p = 0.002), in Mexican Americans (14.9%) and non-Hispanic blacks (8.1%) compared to non-Hispanic whites (7.1%, p < 0.001). High alcohol consumption, hepatitis B or C infection and high transferrin saturation were found in only 31.0% of cases. Aminotransferase elevation was unexplained in the majority (69.0%). In both men and women, unexplained aminotransferase elevation was significantly associated with higher body mass index, waist circumference, triglycerides, fasting insulin, and lower HDL; and with type 2 diabetes and hypertension in women (all p < 0.05). Aminotransferase elevation was common in the United States, and the majority could not be unexplained by alcohol consumption, viral hepatitis or hemochromatosis. Unexplained aminotransferase elevation was strongly associated with adiposity and other features of the metabolic syndrome, and thus may represent nonalcoholic fatty liver disease.
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PMID:The prevalence and etiology of elevated aminotransferase levels in the United States. 1280 14

Ribonuclease inhibitor (RI) is an acidic cytosolic glycoprotein with molecular weight of about 50 kDa, which contains 32 cysteine residues. It is possibly that RI may have antioxidant effect by thiol-disulfide exchange reaction. We studied the effects of RI over-expression on the rat glial cell line C6 injured with H2O2. The transfected C6 cells with RI cDNA (C6') had higher viability, less LDH leakage and MDA contents, but more GSH contents compare that in the control C6 cells. In transfected C6 cells, the activities of CAT and GST were higher than that in the control C6 cells. Without H202 stress, the activities of CAT and GST in the C6' cells were 1.73 and 3.62 times that in the control C6 cells, respectively; With 1.00 mmol/L H2O2 stress, the activities of CATand GSTin the C6' cells were 3.38 and 2.11 times that in the C6 cells, respectively. These results suggest that the over-expression RI has antioxidant activity and it is able to protect cells from per-oxidative injuries. Moreover, we investigated whether RI has a protective role against mouse hepatic damage in vivo. The mice pretreated with different doses of human RI were injected by CC14. The results show that the SOD activities of therapy groups were significantly higher than that of the control group (p < 0.01), while the contents of MOD and activities of ALT and AST in blood were remarkably lower than that of the control group (p < 0.01). Pathological examination shows that the degree of damage was alleviated with RI therapy. These results suggest that RI has the protective role against mouse hepatic damage induced by CC14. The anti-oxidative effects of RI may play an important role in cell protection from per-oxidative injuries.
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PMID:The antioxidant effects of ribonuclease inhibitor. 1470 97

Non-alcoholic steatohepatitis (NASH) can vary from mild hepatic inflammation and steatosis to cirrhosis, and is most frequently associated with obesity, Type 2 diabetes mellitus, hypertension, and the female gender. The prevalence of fatty liver and NASH in the general population is 20% and 3%, respectively. In Western countries, 15-20% of the population is obese and 74-90% of them exhibit fatty changes in liver biopsies. We assessed the prevalence of NASH in morbidly obese patients and evaluated serum TGF-beta1 concentrations in different stages of liver fibrosis. Thirty-five obese patients were evaluated, nine male and 26 female. Their mean body mass index (BMI) was 43.62 +/- 7.92 kg/m2. Liver biopsies were evaluated by light microscopy; graded and staged according to Brunt's system. Serum obtained from patients was used to detect TGF-beta1 concentrations by an ELISA method. Serum alanine transaminase (ALT) levels were elevated in four of the patients and the mean level was 49.98 +/- 94.7 (8-65 IU/L). NASH was diagnosed in 32 (91%) of the biopsies, and the most common pattern seen was mixed, predominantly macrovesicular steatosis. Some degree of fibrosis was seen in 34 (97%) of the biopsies and 22 (63%) were at stage 2 (range 1-3). Serum concentrations of TGF-beta1 had no relationship with the stages of fibrosis. In conclusion, NASH and fibrosis are common in our obese patients, as observed in other studies. TGF-beta1 may play a key role in liver fibrogenesis.
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PMID:Obesity-related non-alcoholic steatohepatitis and TGF-beta1 serum levels in relation to morbid obesity. 1511 94

Obesity and type 2 diabetes are associated with nonalcoholic steatohepatitis (NASH), but an obese/diabetic animal model that mimics human NASH remains undefined. We examined the induction of steatohepatitis and liver fibrosis in obese and type 2 diabetic db/db mice in a nutritional model of NASH and determined the relationship of the expressions of osteopontin (OPN) and leptin receptors to the pathogenesis of NASH. db/db mice and the corresponding lean and nondiabetic db/m mice were fed a diet deficient in methionine and choline (MCD diet) or control diet for 4 wk. Leptin-deficient obese and diabetic ob/ob mice fed similar diets were used for comparison. MCD diet-fed db/db mice exhibited significantly greater histological inflammation and higher serum alanine aminotransferase levels than db/m and ob/ob mice. Trichrome staining showed marked pericellular fibrosis in MCD diet-fed db/db mice but no significant fibrosis in db/m or ob/ob mice. Collagen I mRNA expression was increased 10-fold in db/db mice, 4-fold in db/m mice, and was unchanged in ob/ob mice. mRNA expressions of OPN, TNF-alpha, TGF-beta, and short-form leptin receptors (Ob-Ra) were significantly increased in db/db mice compared with db/m or ob/ob mice. Parallel increases in OPN and Ob-Ra protein levels were observed in db/db mice. Cultured hepatocytes expressed only Ob-Ra, and leptin stimulated OPN mRNA and protein expression in these cells. In conclusion, our results demonstrate the development of an obese/diabetic experimental model for NASH in db/db mice and suggest an important role for Ob-Ra and OPN in the pathogenesis of NASH.
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PMID:Obese and diabetic db/db mice develop marked liver fibrosis in a model of nonalcoholic steatohepatitis: role of short-form leptin receptors and osteopontin. 1525 62

A limited number of studies have reported associations of markers of liver injury, including elevated concentrations of aspartate aminotransferase (AST) and alanine aminotransferase (ALT), with prospective risk of type 2 diabetes. However, only one study has adjusted for a detailed measure of insulin sensitivity (insulin sensitivity index [S(i)]), which is important given associations of obesity and S(i) with nonalcoholic fatty liver disease (NAFLD). Our objective was to investigate the associations of elevated AST and ALT with incident type 2 diabetes among 906 participants in the Insulin Resistance Atherosclerosis Study who were nondiabetic at baseline. S(i) and acute insulin response (AIR) were measured directly from the frequently sampled intravenous glucose tolerance test among black, Hispanic, and non-Hispanic white participants aged 40-69 years. After 5.2 years, 148 individuals had developed type 2 diabetes. Baseline AST and ALT were positively correlated with fasting insulin (r = 0.22 and r = 0.35, respectively), waist circumference (r = 0.18 and r = 0.34), and fasting glucose (r = 0.13 and r = 0.29) and inversely with S(i) (r = -0.18 and r = -0.30; all P < 0.0001). In separate logistic regression models adjusting for age, sex, ethnicity, clinical center, and alcohol consumption, participants in the highest quartiles (Q4) of AST and ALT were at significantly increased risk of incident type 2 diabetes compared with those in the lowest three quartiles (Q1-Q3): AST: odds ratio (OR) 1.73 (95% CI 1.17-2.57); ALT: OR 2.32 (1.36-3.75). After further adjustment for smoking, waist circumference, triglyceride, HDL, impaired glucose tolerance, S(i), and AIR, both AST and ALT remained significantly associated with incident type 2 diabetes: AST, Q4 vs. Q1-Q3: OR 1.98 (1.23-3.17); ALT, Q4 vs. Q1-Q3: OR 2.00 (1.22-3.28). There were no interactions of sex, ethnicity, obesity, impaired glucose tolerance, or S(i) with AST or ALT in the prediction of type 2 diabetes. When entered into the same model with adjustment for demographic variables, both C-reactive protein and ALT independently predicted type 2 diabetes. In addition, AST and ALT were positively associated with incident type 2 diabetes after excluding former and moderate to heavy drinkers. In conclusion, AST and ALT independently predict type 2 diabetes. Baseline elevations of these markers may reflect NAFLD or related pathologies.
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PMID:Elevations in markers of liver injury and risk of type 2 diabetes: the insulin resistance atherosclerosis study. 1544 93


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