Serum leptin levels in patients with nonalcoholic steatohepatitis

OBJECTIVE: Leptin is a peptide hormone that mainly regulates food intake an d energy expenditure of human body. A close correlation between serum lepti n levels and the percentage of body fat stores is well known. Nonalcoholic steatohepatitis (NASH) is a common disorder which causes serum liver enzyme elevation. In this study, the serum leptin levels were investigated in pat ients with NASH to determine a possible role in the pathogenesis and in pat ients with chronic viral hepatitis to ascertain the effect of hepatic infla mmation on serum leptin level. METHODS: Forty-nine patients (38 men, 11 women) with NASH diagnosed by biop sy, 32 patients with biopsy-proven chronic viral hepatitis (21 men and 11 w omen), and 30 healthy adults (17 men, 13 women) enrolled in the study. Fast ing blood samples were obtained, and serum leptin levels were measured by E LISA. Body mass index (BMI) was calculated for all subjects, and serum insu lin, C-peptide, and lipoprotein levels were also detected. RESULTS: The mean serum leptin levels (+/-SEM) were 6.62 +/- 0.71, 4.24 +/- 1.0, and 4.02 +/- 0.46 ng/ml in NASH, chronic hepatitis, and the control g roup, respectively. Mean serum leptin level in the NASH group was significa ntly higher than those in the other groups tested. BMI was also slightly hi gher in the NASH group when compared to the other groups (26.7 +/- 0.3, 23. 7 +/- 0.6, and 24.6 +/- 0.3, respectively). There was a significant correla tion between BMI and serum leptin levels when all the subjects were evaluat ed together (NASH, hepatitis, and control groups, 0.337, p = 0.012) but not in the NASH group when evaluated alone (r = 0.238, p = 0.1). Of the predis posing factors for NASH, obesity was observed in 24% of patients and hyperl ipidemia in 67%. Serum cholesterol and triglyceride levels were significant ly higher in the NASH group than those in controls (p < 0.05). It has been detected that most of these patients consumed high amounts of fat in their dietary habits. CONCLUSIONS: The serum leptin levels were significantly higher in patients with NASH, while they were not affected by chronic hepatitis. This elevatio n is out of proportion to BMI of these patients and may be related to hyper lipidemia most. Elevated serum leptin levels, therefore, may promote hepati c steatosis and steatohepatitis. (C) 2000 by Am. Cell. of Gastroenterology.