Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Previously regarded as an obscure disorder, nonalcoholic steatohepatitis (NASH) has recently emerged as an important chronic liver disease. NASH is within a spectrum of disorders characterized by excessive accumulation of fat in the liver, including simple hepatic steatosis (fatty liver), inflammation and necrosis (steatohepatitis), and fibrosis. Collectively, the disorders are called nonalcoholic fatty liver disease (NAFLD). Estimates of the prevalence of these individual conditions are suspect because liver biopsy is required for definitive diagnosis and is not generally performed. Although these conditions have traditionally been thought of as diseases of obese women, and are frequently associated with diabetes mellitus and hypertriglyceridemia, they have also been identified in lean men. Insulin resistance appears to be a common factor. These conditions are difficult to distinguish from each other clinically, and no biochemical or radiological test reliably establishes the diagnosis. A ratio of serum aspartate to alanine aminotransferase levels of less than one can distinguish NAFLD from alcoholic liver disease, but this is a nonspecific finding. Fatty infiltration imparts a diffuse echogenicity to the liver at ultrasonography, but this test cannot easily distinguish fat from fibrous tissue or identify cases of NASH. Only histological examination can establish the diagnosis of NASH, grade its severity, determine the prognosis and guide treatment.
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PMID:Motion - all patients with NASH need to have a liver biopsy: arguments for the motion. 1242 34

Several human studies suggest that light-to-moderate alcohol consumption is associated with enhanced insulin sensitivity, but these studies are not free of conflicting results. To determine if ethanol-enhanced insulin sensitivity could be demonstrated in an animal model, male Wistar rats were fed a standard chow diet and received drinking water without (control) or with different ethanol concentrations (0.5, 1.5, 3, 4.5 and 7%, v/v) for 4 weeks ad libitum. Then, an intravenous insulin tolerance test (IVITT) was performed to determine insulin sensitivity. Among the ethanol groups, only the 3% ethanol group showed an increase in insulin sensitivity based on the increase of the plasma glucose disappearance rate in the IVITT (30%, P<0.05). In addition, an intravenous glucose tolerance test (IVGTT) was performed in control and 3% ethanol animals. Insulin sensitivity was confirmed in 3% ethanol rats based on the reduction of insulin secretion in the IVGTT (35%, P<0.05), despite the same glucose profile. Additionally, the 3% ethanol treatment did not impair body weight gain or plasma aspartate aminotransferase and alanine aminotransferase activities. Thus, the present study established that 3% ethanol in the drinking water for 4 weeks in normal rats is a model of increased insulin sensitivity, which can be used for further investigations of the mechanisms involved.
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PMID:Low ethanol consumption increases insulin sensitivity in Wistar rats. 1253 36

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

Insulin resistance (IR) commonly is associated with nonalcoholic steatohepatitis (NASH). To establish whether IR causes NASH, this study was undertaken to determine if improving IR would improve the histologic features that define NASH. Thirty adults with prior biopsy evidence of NASH were enrolled to receive rosiglitazone, 4 mg twice daily for 48 weeks. All patients were overweight (body mass index [BMI] > 25 kg/m(2)) and 23% were severely obese (BMI > 35 kg/m(2)); 50% had impaired glucose tolerance or diabetes. Liver biopsy specimens were obtained before beginning treatment and at treatment completion. Twenty-six patients had posttreatment biopsies; of these, 22 had initial protocol liver biopsies that met published criteria for NASH on subsequent blinded evaluation. Within this initial NASH group, the mean global necroinflammatory score significantly improved with treatment and biopsies of 10 patients (45%) no longer met published criteria for NASH after treatment. Significant improvement in hepatocellular ballooning and zone 3 perisinusoidal fibrosis also occurred. Five patients withdrew early; the 25 patients completing 48 weeks of treatment had significantly improved insulin sensitivity and mean serum alanine aminotransferase (ALT) levels (104 initially, 42 U/L at the end of treatment). Adverse effects led to withdrawal of 3 patients (10%). Weight gain occurred in 67% of patients and the median weight increase was 7.3%. Within 6 months of completing treatment, liver enzyme levels had increased to near pretreatment levels. In conclusion, improving insulin sensitivity with rosiglitazone resulted in improved histologic markers of NASH, an observation suggesting that insulin resistance contributes to its development and that improving insulin sensitivity may be important in treating this liver disease.
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PMID:Improved nonalcoholic steatohepatitis after 48 weeks of treatment with the PPAR-gamma ligand rosiglitazone. 1451 88

The reticulocytes and the ageing red blood cells (RBCs) namely young (Y), middle-aged (M) and old RBCs (O) of female Wistar rats from different groups such as control animals (C), controls treated with vanadate (C + V), alloxan-induced diabetic (D), diabetic-treated with insulin (D + I) and vanadate (D + V), were fractionated on a percoll/BSA gradient. The following enzymes were measured - hexokinase (HK), glutathione peroxidase (GSH-Px), glutathione reductase (GSSG-R), glutathione-s-transferase (GST), alanine aminotransferase (AlaAT), aspartate aminotransferase (AsAT) and arginase in the hemolysates of all the RBCs fractions. Decreases in the activity of HK and AsAT by about 70%, arginase and GSH-Px by 30% in old RBCs were observed in comparison to reticulocytes of control animals. Increases in the activity of GSSG-R by 86%, AlaAT by more than 400% and GST by 70% were observed in old RBCs in comparison to reticulocytes of control animals. Alloxan diabetic animals showed a further decrease in the activities of HK in Y RBCs by 37%, M RBCs by 39% and O RBCs by 32%, GSH-Px activity in Y RBCs by 13%, M RBCs by 20% and O RBCs by 33% and GST activity in Y RBCs by 14%, M RBCs by 42% and O RBCs by 60% in comparison to their corresponding cells of control animals. An increase in the activity of all the enzymes studied was also observed in reticulocytes of diabetic animals in comparison to reticulocytes of controls. The GSSG-R activity was found to be increased in Y RBCs by 49%, M RBCs by 67% and O RBCs by 64% as compared to the corresponding age-matched cells of control animals. The activity of arginase also decreased in Y RBCs by about10%, M RBCs by 20% and O RBCs by 30% in comparison to the age-matched cells of control animals. A decrease in the activity of AsAT in Y and M RBCs by 30%, and O RBCs by 25% was observed in diabetic animals in comparison to the age-matched cells of control animals. The activity of AlaAT was found to be decreased by more than 10% in Y and M RBCs and 25% in O RBCs of diabetic animals in comparison to the age-matched cells of control animals. Insulin administration to diabetic animals reversed the altered enzyme activity to control values. Vanadate treatment also reversed the enzyme levels except for that of GST in old cells.
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PMID:Protective effects of sodium orthovanadate in diabetic reticulocytes and ageing red blood cells of Wistar rats. 1528 6

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

Insulin is involved in coronary heart disease through diabetes and metabolic syndrome. A great deal is known about insulin and its correlates, as well as factors related to changes in insulin. However, few studies consider the broad variety of correlates simultaneously. Therefore, the aims of the present study were to characterize the main factors of biological variation affecting serum insulin concentration and to establish reference limits of insulinemia in a presumably healthy French population. Insulin was measured using a microparticular enzymatic immunoassay. A total of 646 subjects aged 11-58 years from the STANISLAS cohort and divided into four groups of 162 males, 157 females, 163 boys and 164 girls, were included in the statistical analyses. In the whole population, serum insulin concentration varied from 0.80 to 54.60 microU/ml. Significant factors affecting insulin were age, gender, body mass index and glucose, in addition to alanine aminotransferase and high-density lipoprotein cholesterol in men, triglycerides and oral contraceptive use in women, and alkaline phosphatase in girls. In summary, we presented biological correlates of insulin in both healthy French male and female adults and children/adolescents and determined reference limits for insulin for each group. These results will contribute to a better interpretation of insulin data in further studies and laboratory investigations.
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PMID:Age- and sex-related reference values for serum insulin concentration and its biological determinants in a French healthy population. The STANISLAS cohort. 1555 73

Insulin resistance (IR), glucose intolerance and diabetes mellitus are commonly associated with cirrhosis. The exact pathogenetic mechanisms responsible are still unknown; however, they may be related to both hepatitis C virus itself and to liver injury. IR may be the earliest abnormality, which in the following years may progress to clinical diabetes mellitus. The aim of this study was to investigate the presence of IR by euglycaemic hyperinsulinemic clamp technique, in chronic hepatitis C patients. 15 patients and nine healthy controls without any known condition that may affect IR were enrolled to the study. Chronic hepatitis C was diagnosed by liver biopsy (hepatic activity index was also determined in 10 patients) and appropriate viral and biochemical tests. Eight patients were given interferon therapy, which had been stopped for at least 3 months before the study. Euglycaemic hyperinsulinemic clamp technique was performed as previously described and peripheral glucose utilisation rate, M value, was calculated in mg/kg/min by infusion of 40 IU/m2/min regular insulin. M value of the control group was significantly higher than that of chronic hepatitis C patients (M = 5.1+/-1 vs. 3.7+/-1; p = 0.004), which was consistent with IR in the patient group. There was no significant correlation between the M value and alanine aminotransferase, aspartate aminotransferase and hepatic activity index (p = 0.621, 0.549, 0.479, respectively). Our results suggest that IR is present in chronic hepatitis C patients; it is not directly related to hepatic injury, moreover, it may be associated with some component(s) inherent to hepatitis C virus.
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PMID:Insulin resistance in chronic hepatitis C. 1560 64

The study was planned to determine the efficacy and safety of adding rosiglitazone to a combination of glimepiride and metformin therapy with insufficiently controlled type 2 diabetes. This was an open-label study with a follow-up period of 26 weeks. Thirty patients were taking 3 mg glimepiride two times and 850 mg metformin two times per day. Patients were told to take one rosiglitazone 4 mg tablet before breakfast additionally. The primary efficacy measure was the mean change in HbA1c from baseline to the end of the study. Secondary efficacy parameters included the mean changes from baseline to the end of the study in fasting plasma glucose (FPG) and insulin levels, as well as total cholesterol, HDL-C, LDL-C, triglycerides, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels. Mean HbA1c levels decreased significantly from 7.54 +/- 0.9% to 6.57 +/- 0.7% (p < 0.001) at 26th week. FPG levels fell from 169.39 +/- 37.8 mg/dl to 135.69 +/- 28.0 mg/dl (p < 0.001), respectively. Insulin levels decreased from 19.60 +/- 9.8 U/L to 14.66 +/- 11.6 U/L (p = 0.026) at 26th week. No one experienced elevations of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels greater than 2.5 times the upper limit of the reference range. This study confirms that the addition of rosiglitazone (4 mg/day) to sulphonylurea and metformin treatment for patients with type 2 diabetes improves glycemic control, is safe, and generally well tolerated.
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PMID:Addition of rosiglitazone to glimepirid and metformin combination therapy in type 2 diabetes. 1564 69

Fatty liver at ultrasounds, with/ without raised plasma levels of hepatic enzymes, is common in obesity. In most cases, it is the hallmark of non-alcoholic fatty liver disease (NAFLD), a potentially progressive disease associated with insulin resistance and the metabolic syndrome (MS). We tested the hypothesis that insulin resistance per se might be associated with hepatocellular necrosis. Alanine and aspartate aminotransferases (ALT and AST; no.=799) and gamma-glutamyltranspeptidase (GGT; no.=459) were analyzed in a group of treatment-seeking obese patients recruited in 12 Italian medical centers. Insulin resistance was calculated by the homeostasis model assessment method (HOMA-IR; no.=522). Median ALT and AST increased with increasing obesity class (p=0.001 and p=0.005) and exceeded normal limits in 21.0% of cases. Also HOMA-IR increased with the obesity class (p<0.0001), and was higher in subjects with elevated ALT (median, 4.93 vs 2.89; p<0.0001). A significant correlation was observed between HOMA-IR and ALT (R2=0.208; p<0.0001), as well as between HOMA-IR and AST or GGT (R2=0.112 and R2=0.080; p<0.0001). The correlation was maintained when cases with elevated enzyme levels were omitted from analysis. Diabetes and hypertriglyceridemia were the features of the MS most commonly associated with raised liver enzymes. In logistic regression, after correction for age, gender, BMI and features of the MS, HOMA-IR maintained a highly predictive value for raised ALT, AST and GGT. We conclude that in obesity insulin resistance is a risk factor for raised liver enzyme levels, possibly related to NAFLD.
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PMID:Aminotransferase and gamma-glutamyltranspeptidase levels in obesity are associated with insulin resistance and the metabolic syndrome. 1596 6


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