Obesity and related parameters of non-alcoholic steatohepatitis.

BACKGROUND/AIMS: The aim of this prospective study was to evaluate the clinical, biochemical and histopathological parameters of nonalcoholic steatohepatitis and the conditions associated with this disease. METHODS: Twenty-four patients were included in the study, each having been diagnosed with nonalcoholic steatohepatitis on the basis of liver biopsy and elimination of other possible causes of elevated aminotransferase levels. Measurements of degree of obesity, liver enzymes and serum lipids were recorded before liver biopsy and reevaluated after one or two months of a standard exercise and diet program. Serum insulin levels were also measured. Each liver biopsy was histologically examined for steatosis, inflammation, fibrosis, necrosis and iron storage, and semiquantitave assessment of these was recorded for three separate hepatic zones. RESULTS: The prevalence of obesity in the group was 79.2%, while the figure for overt and latent diabetes mellitus combined was 33.3%, and for hyperlipidemia was 83.3%. Compared to the rest of the group, the patients with severe steatosis had significantly higher serum lipid (particularly high triglyceride) and insulin levels (p<0.05 for both). There was a correlation between steatosis and obesity (p=0.06). More severe obesity, higher insulin and elevated aspartate aminotransferase were positively correlated with inflammation, whereas elevated serum triglyceride was negatively correlated with inflammation. There was a tendency towards normalization of liver enzyme levels after weight loss and dietary restrictions. CONCLUSIONS: Obesity and hyperlipidemia were associated with nonalcoholic steatohepatitis in the group studied. Obesity is not a factor in every case, but the study showed that restricted diet and exercise are significant forms of therapy for nonalcoholic steatohepatitis.     

Serum thioredoxin levels as a predictor of steatohepatitis in patients with nonalcoholic fatty liver disease

BACKGROUND/AIMS: Thioredoxin (TRX) is a stress-inducible thiol-containing protein. The aim of this study was to evaluate the clinical significance of serum TRX in patients with nonalcoholic steatohepatitis (NASH) or simple steatosis. METHODS: Serum TRX levels were determined using an enzyme-linked immunosorbent assay kit in 25 patients with NASH, 15 patients with simple steatosis, and 17 healthy volunteers. RESULTS: Serum TRX levels (medians and (ranges), ng/ml) were significantly elevated in patients with NASH (60.3 (17.6-104.7)), compared to those in patients with simple steatosis (24.6 (16.6-69.7), P=0.0009) and in healthy controls (23.5 (1.3-50.7), P<0.0001). Serum ferritin levels in patients with NASH were also significantly higher than the levels in patients with simple steatosis. The receiver operating characteristic curve confirmed that serum TRX and ferritin levels were predictors for distinguishing NASH from simple steatosis. Higher grades of histological iron staining were observed in NASH than in simple steatosis. Serum TRX tended to increase in accordance with hepatic iron accumulation and the histological severity in patients with NASH. CONCLUSIONS: The pathogenesis of NASH may be associated with iron-related oxidative stress. The serum TRX level is a parameter for discriminating NASH from simple steatosis as well as a predictor of the severity of NASH.     

Elevation of serum thioredoxin levels in patients with nonalcoholic steatohepatitis.

Thioredoxin (TRX) is induced by many oxidative stresses. Serum TRX levels were significantly elevated in nonalcoholic steatohepatitis (NASH) patients, as compared to simple fatty liver (FL) patients or healthy controls. Serum TRX levels in NASH patients were significantly correlated with serum ferritin levels, but not with other variables. Removal of hepatic excess iron by phlebotomy significantly decreased the serum levels of TRX and ALT in NASH patient. Therefore, the pathogenesis of NASH may be associated with iron-related oxidative stress. The serum TRX level is a parameter for discriminating NASH from FL.     

血清内脏脂肪素、脂联素与非酒精性脂肪性肝病临床病理的关系

目的探讨NAFLD临床病理改变与血清内脏脂肪素（visfatin）、脂联素（adiponectin）水平的相关性。方法取54例患者肝组织标本,根据其病理改变分为正常对照组（Control组）、单纯性脂肪肝组（ss组）、非酒精性脂肪性肝炎（NASH组）。酶联免疫法测定所有患者的血清visfatin、adiponectin水平,并比较各组之间visfatin、adiponectin的差异。结果54例标本中：Control组23例,SS组11例,NASH组20例。NASH组血清visfatin{k~于Control组（P=O．012）和sS组（P=0．021）;SS组血清visfatin较Control组有降低的趋势;Control组血清adiponectin高于NASH组（P=0．024）和sS组（P=0．039）：NASH组较Ss组有降低的趋势。结论在NAFLD患者中,随着肝组织脂肪变及炎症的加重,其血清visfatin、adiponectin水平逐渐降低。     

Characterization of pathogenic and prognostic factors of nonalcoholic steatohepatitis associated with obesity

BACKGROUND/AIMS: Nonalcoholic steatohepatitis is an emerging clinical problem among the obese population. However, risk factors of progression to advanced forms of liver disease in this particular group of patients remain to be defined. METHODS: The demographics and clinical and histologic features of 46 obese patients were evaluated. The intrahepatic immunological phenotype was assessed in all liver biopsy samples by immunohistochemistry. RESULTS: Histologic findings of nonalcoholic steatohepatitis were observed in 69.5% of the obese population studied and significant fibrosis was evident in 41% of patients with nonalcoholic steatohepatitis. Age (p=0.003), degree of steatosis (p=0.000002), and grade of inflammation (p=0000) at liver biopsy were independent variables positively associated with fibrosis. Intrahepatic expression levels of several immunologic markers of inflammation as well as nitric oxide derivatives were significantly higher in the severe forms of nonalcoholic steatohepatitis than in the mildest forms. CONCLUSIONS: Obese persons with higher age, with greater degrees of hepatic steatosis, and specially those with increased grades of intrahepatic inflammation have the greatest risk for progression to fibrotic liver disease. An oxidative stress-triggered intrahepatic inflammatory response appears to be important in the pathogenesis of nonalcoholic steatohepatitis in obesity.     

Fat and the liver--a molecular overview

Nonalcoholic fatty liver disease (NAFLD) is a chronic liver disease that occurs in nondrinkers but which cannot be distinguished from alcohol-induced liver disease histologically. There are no diagnostic blood tests for NAFLD but the disease is associated with several insulin-resistant states, including obesity, type 2 diabetes mellitus and dyslipidemia. Most of the liver-related morbidity and mortality that accompany NAFLD occur in patients who develop cirrhosis. The latter is most likely to occur in individuals who have progressed from simple steatosis (fatty liver) to steatohepatitis, a chronic inflammatory liver lesion. The mechanisms that promote the transition from steatosis to nonalcoholic steatohepatitis appear to involve multiple cellular adaptations to the oxidative stress that occurs when fatty acid metabolism is deranged during insulin resistance. A better understanding of these mechanisms is desired to target treatments to prevent and/or reverse nonalcoholic steatohepatitis, thereby aborting the evolution of cirrhosis.     

A high-fat diet and regulatory T cells influence susceptibility to endotoxin-induced liver injury

In nonalcoholic fatty liver disease, the pathogenesis of progression from simple steatosis to steatohepatitis has not been fully clarified. Many factors, including oxidative stress and hepatic immune regulation, contribute to the inflammation in steatosis. Because regulatory T cells (Tregs) are important components of immune regulation, we have now investigated their role in the pathogenesis of nonalcoholic steatohepatitis. Wild-type C57BL/6 mice were fed a high-fat (HF) diet to induce steatosis, and the hepatic lymphocyte population was analyzed by flow cytometry. HF-induced steatosis was associated with the depletion of hepatic Tregs and led to up-regulation of the inflammatory tumor necrosis factor-alpha signaling pathway. When challenged by exogenous lipopolysaccharide, the HF-fed mice developed liver inflammation. In contrast, the adoptive transfer of Tregs decreased inflammation in HF-fed mice. In comparison with effector T cells, Tregs had a lower expression of Bcl-2 and, therefore, increased susceptibility to oxidative stress-induced apoptosis. The treatment of mice with the antioxidant Mn(III)tetrakis(4-benzoic acid)porphyrin chloride reduced Treg apoptosis, increased the number of hepatic Tregs, and decreased hepatic inflammation in HF-fed mice. CONCLUSION: Our results indicate that increased oxidative stress in a fatty liver causes the apoptosis of Tregs, reduces the number of hepatic Tregs, and leads to a lowered suppression of inflammatory responses. This scenario is likely one of the pathogenetic mechanisms that facilitate the transformation of simple steatosis into steatohepatitis when a fatty liver is exposed to second or third hits.     

Steatosis and steatohepatitis in diabetic patient

Nonalcoholic fatty liver disease (NAFLD) is an increasingly recognized condition of excess fat deposition within the liver. NAFLD includes a spectrum of liver pathology ranging from bland hepatic steatosis to steatohepatitis and cirrhosis. Nonalcoholic steatohepatitis (NASH) is an inflammatory and fibrosing condition of the liver thought to be an intermediate stage of NAFLD that may progress to endstage liver disease, liver-related death and hepatocellular carcinoma. Nonalcoholic steatohepatitis (NASH) is a common liver disease that is characterized histologically by hepatic steatosis, lobular inflammation, and hepatocellular ballooning, it can progress to cirrhosis in up to 15% of patients. There is currently no therapy that is of proven benefit for nonalcoholic steatohepatitis. The disease is closely associated with insulin resistance and features of the metabolic syndrome such as obesity (increased waist circumference), hypertriglyceridemia, and type 2 diabetes. The pathologic criteria are now well established and the diagnosis can only be made once the absence or limited use of alcohol is confirmed. In addition to insulin resistance, oxidative stress has been implicated as a key factor contributing to hepatic injury in patients with nonalcoholic steatohepatitis. Thus, both insulin resistance and oxidative stress are attractive targets for therapy in patients with this disease. Several pilot studies have provided evidence that insulin sensitizers such as thiazolidinediones and antioxidants such as vitamin E improve clinical and histologic features of nonalcoholic steatohepatitis. The medical evidence of a benefit, however, is limited, because these studies had small samples and were performed at single centers. Moreover, a recent multicenter trial showed a reduction in hepatic steatosis but no improvement in markers of cell injury after a year of rosiglitazone therapy. The value of these remains uncertain. Until now the best trial was done by Sanyal, who studied 240 patients divided into 3 groups (pioglitazone versus vitamin E versus placebo)--multicenter, randomized, double-blind clinical trial in non-diabetics.     

Fertile females with nonalcoholic fatty liver disease (NAFLD) have higher levels of ALT than postmenopausal females: implications for the influence of fertility on NAFLD

BACKGROUND/AIMS: Insulin resistance recently has been reported to play a major role in nonalcoholic fatty liver disease (NAFLD). We evaluated the influence of fertility on fatty liver injury in fertile and postmenopausal women with insulin resistance. METHODOLOGY: We investigated 152 patients with noninsulin-dependent diabetes mellitus without insulin treatment; 46 males, 52 fertile women and 54 postmenopausal women. All had liver damage and/or steatosis recognized by ultrasonography. We measured the fasting serum levels of C-peptide and insulin, as markers of insulin resistance, and the serum levels of ALT. The severity of liver steatosis was judged by ultrasonography. RESULTS: Fertile females had significantly higher levels of ALT and demonstrated a more significant correlation between serum levels of ALT and C-peptide or insulin than did the postmenopausal females or males. Fertile females with moderate to severe steatosis had significantly higher levels of ALT than those with mild or no steatosis, although such a significant difference was not found in postmenopausal females or males. CONCLUSIONS: We demonstrate that fertility is an important factor in fatty liver damage of NAFLD with insulin resistance, suggesting that estrogen may exacerbate nonalcoholic steatohepatitis.     

Nonalcoholic fatty liver disease: evolution after gastric bypass

BACKGROUND: Nonalcoholic fatty liver disease is highly prevalent among morbidly obese patients and can progress from steatosis to steatohepatitis and chronic liver disease. AIM: To determine the effect of gastric bypass operation in the incidence of fatty liver disease and associated co-morbidities in morbidly obese patients. METHODS: Patients were prospectively evaluated in the pre-operative period and after at least 6 months after operation. We analysed: antropometric data, co-morbidities, use of medications, cholesterol and triglycerides levels, liver tests and incidence of nonalcoholic fatty liver disease. All patients with abnormal liver tests were subjected to per-operative liver biopsy. RESULTS: Twenty eight patients with nonalcoholic fatty liver disease with a mean body mass index of 42 +/- 4 kg/m(2) were evaluated. Twenty five patients had 59 co-morbidities and the most frequent were: elevated triglycerides (n = 23), elevated cholesterol (n = 13) and elevated blood pressure (n = 11). Biopsy was done in 22 patients: 10 presented moderate steatosis, 5 mild steatosis and 7 steatohepatitis. After follow-up of 230 days in average they presented weight excess loss of 64%, body mass index reduction to 29,6 +/- 3 kg/m(2) and 21 co-morbidities in 13 patients. There was a significant decrease in the number of patients with elevated triglycerides, elevated cholesterol, elevated blood pressure and in the incidence of nonalcoholic fatty liver disease. CONCLUSION: The weight loss secondary to the gastric bypass is associated with decrease in the incidence of nonalcoholic fatty liver disease and other co-morbidities.     

Effects of obstructive sleep apnea syndrome on hepatic steatosis and nonalcoholic steatohepatitis.

Hepatic steatosis occasionally progresses to nonalcoholic steatohepatitis. This study was designed to examine whether non-obese patients with obstructive sleep apnea-hypopnea syndrome (OSAHS) were prone to develop hepatic steatosis and whether repeated hypoxemia contributed to the progression of steatohepatitis. This study included 83 OSAHS patients and 41 age-, body mass index (BMI)- and gender-matched non-OSAHS patients diagnosed by polysomnography. Hepatic steatosis was defined by a liver/spleen ratio <0.9 on abdominal computerized tomography, and latent steatohepatitis was evaluated based on serum levels of type III procollagen (P-III-P). Visceral fat (V-fat) accumulated much more in OSAHS patients. Liver/spleen ratios in OSAHS patients correlated negatively with BMI and, especially, with the amount of visceral fat. Serum levels of P-III-P in OSAHS patients correlated negatively with the average of oxygen saturation during sleep, and positively with BMI, the apnea-hypopnea index (AHI) and the amount of V-fat. Multiple regression analysis showed that average SaO(2) was the only explanatory variable for P-III-P values, but AHI, BMI and V-fat was not. These observations confirmed that non-obese patients with OSAHS are at a risk for visceral obesity, and suggested that oxygen desaturation during sleep is a risk for developing latent steatohepatitis, especially in patients with substantial hepatic steatosis.     

Systemic inflammation in nonalcoholic fatty liver disease is characterized by elevated levels of CCL2

BACKGROUND/AIMS: To elucidate the role of systemic inflammation in nonalcoholic fatty liver disease (NAFLD). METHODS: Serum samples in 47 patients with histologically verified NAFLD (22 with simple steatosis and 25 with nonalcoholic steatohepatitis [NASH]), and in 30 age-, sex- and ethnicity-matched healthy controls, were assessed for (i) general markers of inflammation (C-reactive protein [CRP], tumor necrosis factor [TNF]-alpha, and interleukin [IL]-6), (ii) chemokines (CC-chemokine ligand [CCL] 2/monocyte chemoattractant protein [MCP]-1, CCL19 and CCL21), (iii) adipocytokines related to insulin resistance and inflammation (adiponectin and leptin) and (iv) a marker of oxidative stress (8-isoprostane-F2alpha). RESULTS: Serum levels of several inflammatory cytokines were increased in NAFLD as compared to controls, and IL-6 (P=0.017), CCL2/MCP-1 (P=0.008) and CCL19 (P=0.001), but not CRP (P=0.199), remained elevated also after correction for sex, body mass index (BMI) and age. Comparing NASH with simple steatosis, levels of TNF-alpha (P=0.024) and CCL2/MCP-1 (P=0.012) were elevated and adiponectin (in women) (P=0.001) were decreased also after adjustment for sex, BMI and presence of the metabolic syndrome. CONCLUSIONS: Our results indicate that patients with NAFLD are characterized by a low-grade systemic inflammation. The high CCL2/MCP-1 levels in NASH might be of importance for the conversion from simple steatosis to NASH.     

Increased intestinal permeability in pathogenesis and progress of nonalcoholic steatohepatitis in rats

AIM: To investigate whether increased intestinal permeability contributes to the pathogenesis and progress of nonalcoholic steatohepatitis by observing its dynamic change in rat models. METHODS: Rat models of nonalcoholic steatohepatitis were established by giving a fat-rich diet. The rats were sacrificed at wk 8, 12 and 16 during the study. Rats fed with normal diet were taken as control. Plasma D-lactate, plasma diamine oxidase, serum lipids and liver transaminases were measured in blood of the femoral artery. Hepatic steatosis and inflammation were assessed by haematoxylin-eosin staining. RESULTS: A rat model of nonalcoholic steatohepatitis was established successfully. Plasma D-lactate level in model group at wk 8, 12 and 16 and diamine oxidase level in model group at wk 12, 16 increased significantly compared with those in control group. There were notable differences of D-lactate and diamine oxidase level in model group between wk 8 and 12 as well as between wk 12 and 16. Serum lipids, liver transaminases and liver injury also increased with disease development. CONCLUSION: Increased intestinal permeability caused by intestinal bacterial overgrowth and endotoxin-induced intestinal destruction exists in rats with nonalcoholic steatohepatitis, which may partially explain the pathogenesis and progress of this disease.     

Amelioration of Steatohepatitis with Pentoxifylline in a Novel Nonalcoholic Steatohepatitis Model Induced by High-Fat Diet

We sought to evaluate the effects of pentoxifylline (PTX) on steatohepatitis in a novel experimental nonalcoholic steatohepatitis (NASH) model induced by a high-fat diet (HFD). Thirty-three male Sprague-Dawley rats were randomly divided into 3 groups. The first group received only standard rat diet (control group); groups 2 (placebo group) and 3 were given HFD, ad libitum. After week 4, 0.5 mL of physiologic serum was injected subcutaneously to the placebo group and 50 mg/kg/d PTX was given intraperitoneally to the third group (group PTX). After 6 weeks all rats were humanely killed. Serum biochemistry, tumor necrosis factor-α (TNF-α), plasma, and liver tissue malondialdehyde (MDA) were analyzed. Histopathologically, steatosis, ballooning degeneration, inflammation, and fibrosis were determined. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels, plasma and liver tissue MDA, and plasma TNF-α levels were significantly higher in placebo group than in the control group. Tumor growth factor-β levels, however, were comparable in the placebo and control groups. On histopathologic examination, steatosis, inflammatory cells per square millimeter, and ballooning degeneration were significantly higher in the placebo group than in the control group. No fibrosis or Mallory bodies were found in the placebo group. AST, ALT, plasma and liver tissue MDA, and plasma TNF-α levels were significantly lower in PTX group compared to the placebo group. Histopathologically, steatosis, mean number of inflammatory cells/mm² and ballooning degeneration in PTX group were also significantly lower than in the placebo group. In conclusion, PTX strikingly ameliorates steatohepatitis in this novel NASH model not only by inhibiting the TNF-α but also suppressing the oxidative stress markers.     

Palmitic acid induces production of proinflammatory cytokine interleukin-8 from hepatocytes

Obesity and the metabolic syndrome are closely correlated with hepatic steatosis. Simple hepatic steatosis in nonalcoholic fatty liver disease can progress to nonalcoholic steatohepatitis (NASH), which can be a precursor to more serious liver diseases, such as cirrhosis and hepatocellular carcinoma. The pathogenic mechanisms underlying progression of steatosis to NASH remain unclear; however, inflammation, proinflammatory cytokines, and oxidative stress have been postulated to play key roles. We previously reported that patients with NASH have elevated serum levels of proinflammatory cytokines, such as interleukin-8 (IL-8), which are likely to contribute to hepatic injury. This study specifically examines the effect of hepatic steatosis on IL-8 production. We induced lipid accumulation in hepatocytes (HepG2, rat primary hepatocytes, and human primary hepatocytes) by exposing them to pathophysiologically relevant concentrations of palmitic acid to simulate the excessive influx of fatty acids into hepatocytes. Significant fat accumulation was documented morphologically by Oil Red O staining in cells exposed to palmitic acid, and it was accompanied by an increase in intracellular triglyceride levels. Importantly, palmitic acid was found to induce significantly elevated levels of biologically active neutrophil chemoattractant, IL-8, from steatotic hepatocytes. Incubation of the cells with palmitate led to increased IL-8 gene expression and secretion (both mRNA and protein) through mechanisms involving activation of nuclear factor kappaB (NF-kappaB) and c-Jun N-terminal kinase/activator protein-1. CONCLUSION: These data demonstrate for the first time that lipid accumulation in hepatocytes can stimulate IL-8 production, thereby potentially contributing to hepatic inflammation and consequent liver injury.     

Nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease is a clinicopathologic syndrome that encompasses several clinical entities. The spectrum of conditions ranges from simple steatosis to steatohepatitis, fibrosis and end stage liver disease. The condition was originally described in obese, diabetic, middle-aged females without a history of significant alcohol use with liver histology consistent with alcoholic hepatitis. It is known that this entity occurs without any particular sex predilection, in lean individuals, as well as an increasing number of obese children. Other terms have been used to describe this clinical entity such as alcohol-like hepatitis, pseudo-alcoholic hepatitis, diabetic hepatitis and steatonecrosis. Ludwig and colleagues introduced the term nonalcoholic steatohepatitis (NASH) to describe patients fitting the picture of alcoholic hepatitis but without a history of significant alcohol abuse. The term nonalcoholic fatty liver disease (NAFLD) is used more frequently to include the spectrum of conditions that range from steatosis through steatohepatitis, fibrosis and cirrhosis. NASH is reserved for patients with steatohepatitis and fibrosis. NAFLD is now being recognized as the most common cause of elevated liver enzymes in the United States. Although the exact etiology of NAFLD is not known, it may be caused by insulin resistance coupled with increased oxidative stress to the hepatocytes. No specific therapy has been approved for this condition and the mainstay of management is weight loss.     

The ratio of aspartate aminotransferase to alanine aminotransferase: potential value in differentiating nonalcoholic steatohepatitis from alcoholic liver disease

OBJECTIVE: The ratio of aspartate aminotransferase (AST) to alanine aminotransferase (ALT) is often greater than 2:1 in alcoholic hepatitis. The purpose of this study was to determine whether this ratio may be used to distinguish nonalcoholic steatohepatitis (NASH) from alcoholic liver disease. METHODS: Patients with NASH were matched with controls with alcoholic liver disease based on age, gender, and date of diagnosis. The diagnosis of alcoholic liver disease was based on exclusion of other causes and a significant history of alcohol consumption. The diagnosis of nonalcoholic steatohepatitis was based on exclusion of other causes of liver disease and a liver biopsy showing > 10% steatosis and inflammation. The two sided Student t test was used for statistical analysis. RESULTS: From 1990 to 1996, 70 patients with NASH were matched with 70 subjects with alcoholic liver disease. Patients with NASH had a mean AST to ALT ratio of 0.9 (range 0.3-2.8, median 0.7) and subjects with alcoholic liver disease a mean ratio of 2.6 (range 1.1-11.2, median 2.0). The mean AST levels were 66 U/L and 152 U/L, and the mean ALT levels 91 U/L and 70 U/L, in the nonalcoholic steatohepatitis and alcoholic liver disease groups, respectively. Although the absolute aminotransferase levels were significantly different in the two groups (p < 0.05), the greatest difference was observed in the AST to ALT ratio (p < 0.000001). Subset analysis of patients with NASH revealed mean AST to ALT ratios of 0.7, 0.9, and 1.4 for subjects with no fibrosis, mild fibrosis, or cirrhosis, respectively. The differences among these ratios were statistically significant (p < 0.05). CONCLUSIONS: The AST to ALT ratio appears to be a useful index for distinguishing nonalcoholic steatohepatitis from alcoholic liver disease. Although values < 1 suggest NASH, a ratio of > or = 2 is strongly suggestive of alcoholic liver disease.     

The importance of AST / ALT rate in nonalcoholic steatohepatitis diagnosis

BACKGROUND/AIMS: There is a histologic similarity between nonalcoholic steatohepatitis and alcoholic liver disease and in some cases differential diagnosis may be difficult, since some patients do not report abusive alcohol consumption. OBJECTIVE: Evaluating the usefulness of setting the rate AST/ALT for the differential diagnosis of nonalcoholic steatohepatitis and alcoholic liver disease. PATIENTS AND METHODS: Twenty nine obese patients with nonalcoholic steatohepatitis were compared with 28 patients with alcoholic liver disease. The diagnosis of nonalcoholic steatohepatitis was made after exclusion of other causes of liver disease and by histologic findings of, at least, macrovesicular steatosis and hepatocellular necrosis. RESULTS: In patients with nonalcoholic steatohepatitis the medium AST value was 52.3 +/- 21.2 U/L and ALT of 90.1 +/- 37.9 U/L, being the AST/ALT rate lower than 1 in all patients. In patients with alcoholic liver disease the medium AST value was 140 +/- 82.5 U/L and ALT was 50.6 +/- 40.3 U/L. The rate was higher than 1 in all cases and higher than 2 in 24 (85.7%), being statistically significant when compared with patients with nonalcoholic steatohepatitis. CONCLUSION: The AST/ALT rate seems to be useful in the differential diagnosis of liver diseases, while lower than 1 is highly suggestive of nonalcoholic steatohepatitis.