Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0028754 (obesity)
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Nonalcoholic steatohepatitis (NASH) is a histological diagnosis applied to a constellation of liver biopsy findings that develop in the absence of alcohol abuse. Steatosis, a mixed cellular inflammatory infiltrate across the lobule, evidence of hepatocyte injury and fibrosis are the findings that can be seen. This entity is often identified during evaluation of elevated aminotransferases after exclusion of viral, metabolic and other causes of liver disease. Obesity is a major risk factor for NASH. The role of diabetes is less certain, although evidence is accumulating that hyperinsulinism may play an important pathophysiological role. Patients sometimes suffer from right upper quadrant abdominal pain and fatigue; examination may reveal centripetal obesity and hepatomegaly. Although patients are often discovered because of persistent aminotransferase elevations, these enzymes can be normal in NASH. When they are elevated, the alanine aminotransferase level is typically significantly greater than the aspartate aminotransferase level. This can be particularly helpful for excluding occult alcohol abuse. Imaging studies identify hepatic steatosis when the amount of fat in the liver is significant; however, imaging does not distinguish benign steatosis from NASH. Ultimately a liver biopsy is needed to diagnose NASH. The biopsy may be useful for establishing prognosis based on the presence or absence of fibrosis and for excluding other unexpected causes of liver enzyme elevations. Weight loss is the mainstay of treatment for obese patients. About 15% to 40% of NASH patients develop fibrosis; how many of these cases progress to cirrhosis is unknown, but about 1% of liver transplants are performed with a pretransplant diagnosis of NASH.
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PMID:Nonalcoholic steatohepatitis: an evolving diagnosis. 1079 85

A highly prevalent, atypical genotype in low Km aldehyde dehydrogenase (ALDH2) may influence alcohol-induced liver injury because of higher production of acetaldehyde in the liver. In the present study, we examined relationships between the ALDH2 genotype, alcohol intake, and liver-function biomarkers among Japanese male workers. Study subjects were 385 male workers in a metal plant in Japan, who were free from hepatic viruses and did not have higher aminotransferase activities (<100). The subjects completed a questionnaire on alcohol drinking habits and other lifestyles. The ALDH2 genotype was determined by the PCR method followed by restriction-enzyme digestion. In the moderately and heavily drinking groups, those with ALDH2*1/*2 exhibited significantly lower levels than those with ALDH2*1/*1 for all three parameters of liver function, whereas no such differences were observed in the least-drinking group. Multiple linear-regression analysis, adjusting for age, obesity, and smoking habits, revealed that aspartate aminotransferase activity was positively associated with alcohol intake only in those with ALDH2*1/*1. On the other hand, alanine transferase activity was negatively associated with alcohol intake only in those with ALDH2*1/*2. The present study indicates that effects of alcohol intake on liver-function biomarkers are likely to be modified by the ALDH2 genotype in adult males.
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PMID:The ALDH2 genotype, alcohol intake, and liver-function biomarkers among Japanese male workers. 1094 5

Nonalcoholic steatohepatitis, along with other forms of nonalcoholic fatty liver disease, is a chronic liver disease that is attracting increasing significance. It is a clinicopathologic syndrome that was originally described in obese, diabetic females who denied alcohol use but in whom the hepatic histology was consistent with alcoholic hepatitis. This typical patient profile has been expanded and is now recognized to occur even in normal weight males without overt abnormalities in carbohydrate metabolism. Although originally believed to be a benign clinical entity, nonalcoholic steatohepatitis is now recognized as a cause of progressive fibrotic liver disease with adverse clinical sequelae. It is important to emphasize that nonalcoholic steatohepatitis is best considered one type of a larger spectrum of nonalcoholic fatty liver disease that is a consequence of insulin resistance and ranges from fat alone to fat plus inflammation, fat plus ballooning degeneration, and nonalcoholic steatohepatitis, the latter being the most serious form. As with any disease, the clinical importance of nonalcoholic steatohepatitis is related to its prevalence and natural history. Recent studies using different methodologies indicate that in the general population the prevalence of fatty liver and nonalcoholic steatohepatitis is approximately 20% and 3%, respectively. These prevalence rates are increased in certain subpopulations such as obesity and type II diabetes. Of greater concern is the recognition that cirrhosis and liver-related deaths occur in approximately 20% and 8% of these patients, respectively, over a 10-year period. Risk factors for these adverse clinical symptoms include patients older than the age of 45, the presence of diabetes or obesity, an aspartate aminotransferase/alanine aminotransferase ratio > 1 and hepatic histology. However, a number of important unresolved issues must be clarified before the true natural history of this disease can be fully understood.
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PMID:Clinical features and natural history of nonalcoholic steatosis syndromes. 1129 93

It has been proposed that liver dysfunction may contribute to the development of type 2 diabetes. The aim of the present study was to examine whether elevated hepatic enzymes (alanine aminotransferase [ALT], aspartate aminotransferase [AST], or gamma -glutamyltranspeptidase [GGT]) are associated with prospective changes in liver or whole-body insulin sensitivity and/or insulin secretion and whether these elevated enzymes predict the development of type 2 diabetes in Pima Indians. We measured ALT, AST, and GGT in 451 nondiabetic (75-g oral glucose tolerance test) Pima Indians (aged 30 +/- 6 years, body fat 33 +/- 8%, ALT 45 +/- 29 units/l, AST 34 +/- 18 units/l, and GGT 56 +/- 40 units/l [mean +/- SD]) who were characterized for body composition (hydrodensitometry or dual-energy X-ray absorptiometry), whole-body insulin sensitivity (M), and hepatic insulin sensitivity (hepatic glucose output [HGO] during the low-dose insulin infusion of a hyperinsulinemic clamp) and acute insulin response (AIR) (25-g intravenous glucose challenge). Sixty-three subjects developed diabetes over an average follow-up of 6.9 +/- 4.9 years. In 224 subjects, who remained nondiabetic, follow-up measurements of M and AIR were available. At baseline, ALT, AST, and GGT were related to percent body fat (r = 0.16, 0.17, and 0.11, respectively), M (r = -0.32, - 0.28, and -0.24), and HGO (r = 0.27, 0.12, and 0.14; all P < 0.01). In a proportional hazard analysis with adjustment for age, sex, body fat, M, and AIR, higher ALT [relative hazard 90th vs. 10th centiles (95% CI): 1.9 (1.1-3.3), P = 0.02], but not AST or GGT, predicted diabetes. Elevated ALT at baseline was associated prospectively with an increase in HGO (r = 0.21, P = 0.001) but not with changes in M or AIR (both P = 0.1). Higher ALT concentrations were cross-sectionally associated with obesity and whole-body and hepatic insulin resistance and prospectively associated with a decline in hepatic insulin sensitivity and the development of type 2 diabetes. Our findings indicate that high ALT is a marker of risk for type 2 diabetes and suggest a potential role of the liver in the pathogenesis of type 2 diabetes.
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PMID:High alanine aminotransferase is associated with decreased hepatic insulin sensitivity and predicts the development of type 2 diabetes. 1203 78

Abnormal circulating levels of hepatic enzymes are frequently found in subjects displaying hyperlipidemia or obesity or both. At present, there is a paucity of information on the principal cardiovascular risk factors that are associated with elevated plasma levels of hepatic enzyme activity in hyperlipidemic patients. We analyzed the potential relationships between serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and gamma glutamyl transferase (GGT) and cardiovascular and metabolic risk factors in a cohort of 8,501 men and women referred to our outpatient clinic for hyperlipidemia by their general practitioner. In this cohort, 27.6% of patients displayed serum levels of ALT above the upper limit of normal values. Both men and women who exhibited ALT levels superior to the upper limit of the normal range had elevated systolic (SBP) and diastolic blood pressure (DBP), body mass index (BMI), alcohol intake, and serum levels of blood glucose, uric acid, total cholesterol, and triglycerides (P <.0035 for all parameters). In a multivariate analysis, BMI, uric acid, and blood glucose remained significantly associated with ALT levels in men and women. We conclude that cardiovascular and metabolic features characterizing the plurimetabolic syndrome, including serum uric acid levels, are associated with significant elevation of hepatic enzyme activities. Because these abnormalities may not only be reversible but also associated with a poor prognosis, further studies are needed to identify those dyslipidemic patients who are at risk for the development of severe hepatic tissue damage.
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PMID:A constellation of cardiovascular risk factors is associated with hepatic enzyme elevation in hyperlipidemic patients. 1214 84

Nonalcoholic fatty liver disease, an entity that includes nonalcoholic steatohepatitis, is typically a benign, indolent condition. However, in a subset of patients, the clinical course may progress to advanced cirrhosis, end-stage liver disease, or hepatocellular carcinoma. Unfortunately, the pathogenesis, natural history, and potential therapies for these disorders remain poorly understood. Identifying patients who should be targeted for potential treatment remains difficult. Liver biopsy should be considered to assess the degree of hepatic inflammation and fibrosis, because physical examination findings, biochemical parameters, and the results of radiographic studies have been shown to correlate poorly with the severity of steatohepatitis and fibrosis. Although there is some evidence suggesting that obesity, diabetes mellitus, older age, and perhaps an aspartate transaminase:alanine aminotransaminase ratio higher than 1 may be predictors of more advanced fibrosis, histology remains the gold standard. Most patients with simple hepatic steatosis appear to follow a benign course and probably do not require aggressive therapy. Conversely, patients with steatohepatitis with extensive inflammation and fibrosis are the patients who are most likely to benefit from effective therapies. The most commonly recommended treatment is weight loss. Existing data suggest that rapid weight loss may promote hepatic inflammation and fibrosis; therefore, gradual weight loss should be recommended. Large, randomized, controlled trials evaluating the long-term histologic impact and clinical outcomes of weight loss strategies are lacking. Potentially promising pharmacologic therapies include insulin-sensitizing oral hypoglycemic agents such as metformin and the thiazolidenediols, antihyperlipidemic agents such as gemfibrozil or 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, vitamin E and other antioxidants, ursodeoxycholic acid, and betaine. As with weight loss, data regarding the efficacy of these pharmacologic options are limited. In addition, there are no widely accepted guidelines to help direct the clinician in the optimal use of these agents in patients with nonalcoholic fatty liver diseases.
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PMID:Therapeutic Options in Nonalcoholic Fatty Liver Disease. 1240 79

To investigate the associations between obesity and serum hepatic enzyme activities, we measured total body fat (TBF), body mass index (BMI), and hepatic biochemical parameters in 732 apparently healthy adults. TBF was assessed using a body fat analyzer. Serum activities of alanine and aspartate aminotransferase (ALT and AST), gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), and lactate dehydrogenase (LD) were determined by standard spectrophotometric methods. Mean activities (+/- SD) of serum ALT and AST in men with high fatness were 51.2 +/- 12.6 U/L and 32.9 +/- 9.2 U/L, which were significantly higher than those in men with low fatness (23.5 +/- 7.4 U/L and 22.5 +/- 7.8 U/L, p < 0.01). Of 147 men with high fatness, 56 (38.1%) had serum ALT levels above the upper limit of normal, whereas only 9.5% (31/328) of men with low or desirable fatness showed elevated serum ALT activities (p < 0.01). Serum ALT, AST, and GGT activities correlated significantly with TBF in both overweight men and women. Among subjects having high TBF, those with fatty liver showed significantly higher incidence of elevated hepatic enzymes, compared to those without fatty liver. In short, elevated serum hepatic enzyme activities are associated with TBF and a high prevalence of fatty liver is observed in subjects with elevated TBF.
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PMID:Association between elevated serum hepatic enzyme activity and total body fat in obese humans. 1295 39

Although histological hepatitis occurs in the majority of hepatitis C virus (HCV)-infected liver transplant recipients, the natural history is highly variable. Whereas progression to cirrhosis occurs in up to 30% after 3 to 7 years, the disease remains stable in another third of patients, in whom protocol liver biopsies might be avoided. However, there is recent concern that with prolonged follow-up, some patients with initial benign recurrence may develop a late-onset aggressive course. Aims of the study are to determine the incidence and factors associated with this event. Based on yearly protocol biopsies (median, five biopsies; range, three to seven biopsies), we evaluated the histological outcome of 57 HCV type 1b-infected transplant recipients with initial benign recurrence, defined as stable histological state (fibrosis stage F0 or F1) during the first 3 years posttransplantation. Severe late-onset liver damage is defined as progression to F3 or F4 in patients with previous benign recurrence. Potential predictors of this event include demographics, donor-related factors, liver enzyme levels at 1 and 3 (or baseline) years posttransplantation, activity grade and fibrosis stage at 1 and 3 years posttransplantation, nonalcoholic steatohepatitis-related variables occurring within the first 3 years posttransplantation (diabetes, hyperlipidemia, obesity), use of some drugs (renin-angiotensin inhibitors, ursodeoxycholic acid), and the advent of any unusual event. The incidence of severe late-onset liver damage was 35% (n = 20). Twelve transplant recipients progressed to F3, whereas 8 transplant recipients progressed to F4. Sudden histological deterioration was observed on postoperative biopsy 5 in 12 patients; biopsy 6 or 7, in 7 patients; and biopsy 4, in 1 patient. Variables associated with this event in univariate analysis were fibrosis stage and activity grade (and its components) at baseline (P <.0001), recipient female gender (P =.04), alanine aminotransferase (ALT) level at 1 year posttransplantation (P =.02), and aspartate aminotransferase (AST) and ALT levels at baseline (P =.008 and P =.005, respectively). By multivariate analysis, only one variable was retained in the model: fibrosis stage at baseline (relative risk, 11; 95% confidence interval, 3 to 41; P =.0007), whereas AST level almost reached statistical significance (P =.07). In conclusion, delayed HCV-related severe liver damage is not infrequent in transplant recipients with initial benign recurrence, occurring in approximately one third of them. The presence of some degree of fibrosis at baseline appears to predict this sudden change in the natural history of recurrent hepatitis C. Based on these findings, we recommend continuing protocol biopsies and evaluating potential antiviral therapy in transplant recipients with evidence of some fibrosis (even if it is only portal).
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PMID:Delayed onset of severe hepatitis C-related liver damage following liver transplantation: a matter of concern? 1458 75

Ten percent of patients who undergo resection for hepatocellular carcinoma (HCC) associated with chronic liver disease have no detectable cause for this underlying liver disease. Recent studies have shown that patients with cryptogenic chronic liver disease frequently have risk factors for nonalcoholic fatty liver disease (NAFLD). This study examines the incidence of risk factors for NAFLD in patients with chronic liver disease who underwent resection for HCC. Among 210 patients with chronic liver disease who underwent resection for HCC, 18 (8.6%) had no identifiable cause for the underlying liver disease. These patients were assessed for obesity, diabetes mellitus, and histological features of the tumor and the adjacent liver parenchyma. Comparisons were made with matched patients with alcohol- and chronic-viral-hepatitis-related HCC. The prevalence of obesity (50% vs. 17% vs. 14%), diabetes (56% vs. 17% vs. 11%), aspartate aminotransferase/alanine aminotransferase ratio<1 (50% vs. 19% vs. 17%), and steatosis>20% (61% vs. 17% vs. 19%) was significantly higher in patients with cryptogenic liver disease than in patients with alcohol abuse and chronic viral hepatitis (P<0.0001 for each). Well-differentiated tumors were significantly more common in patients with cryptogenic liver disease (89% vs. 64% in patients with alcohol-related HCC vs. 55% in patients with chronic viral hepatitis-related HCC, P<0.0001). In conclusion, the hypothesis that obesity and diabetes mellitus may be important risk factors for cryptogenic chronic liver disease in patients with HCC is supported by the analysis of surgically treated patients. Whether HCC is primarily related to obesity and diabetes mellitus or secondarily to a NAFLD-like parenchymal lesions remains to be clarified.
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PMID:Obesity and diabetes as a risk factor for hepatocellular carcinoma. 1476 43

Nonalcoholic fatty liver disease (NAFLD) has emerged as the most common chronic liver disease in the United States. The histologic spectrum of NAFLD ranges from steatosis liver alone to nonalcoholic steatohepatitis (NASH), which is the most serious form of NAFLD. NASH is a progressive fibrotic disease, in which cirrhosis and liver-related death occur in up to 20% and 12%, respectively, over a 10-year period. NASH-associated cirrhosis also can develop into subacute liver failure, progress to hepatocellular carcinoma, and reoccur post-transplantation. In contrast, steatosis alone has a more benign clinical course, although progression to cirrhosis has occurred in 3% of these patients. The major risk factors for fibrosis include diabetes or obesity, an aspartate aminotransferase/alanine aminotransferase ratio of greater than 1, age older than 50, and hepatic histology.
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PMID:The clinical features, diagnosis and natural history of nonalcoholic fatty liver disease. 1533 Oct 61


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