Serum leptin levels in patients with nonalcoholic chronic liver disease

Background/Aims: The elevated serum leptin level of patients with alcoholic cirrhosis has been reported, however, the precise mechanism is still unkno wn. Leptin expression and protein synthesis have also been detected in acti vated hepatic stellate cells in cell cultures, which play a major role in h epatic fibrosis. We evaluated the serum leptin levels of patients with nona lcoholic liver diseases including cirrhosis and chronic hepatitis. We also investigated the hepatic clearance of leptin by determining the serum lepti n level in blood samples obtained from the portal and hepatic veins. Methodology: The serum leptin level of 44 patients with nonalcoholic chroni c liver disease (male/female = 21/23, cirrhosis/chronic hepatitis = 30/14) and 40 control subjects (male/female = 20/20) was determined in blood sampl es obtained from the antecubital vein by enzyme-linked immunosorbent assay. We also assessed the relationship between the leptin level and various bio chemical tests of liver function. Additionally, we determined the leptin le vels in the portal and the hepatic venous blood (nonalcoholic cirrhosis = 1 0, nonhepatic disease = 4) Results: There were positive correlations between the serum leptin level an d body mass index among males and among females in the liver disease group and in the control group. However, the serum leptin level of the liver dise ase group and control group did not differ significantly. Among the 44 live r disease patients, only the serum cholesterol level was significantly corr elated with the serum leptin level after adjusting for sex and body mass in dex by multiple regression analysis. Furthermore, the leptin level in hepat ic venous blood was significantly fewer than that in portal venous blood. H owever, the ratio of [leptin level in hepatic venous blood]/[leptin level i n portal venous blood] in the cirrhosis group, and that in the nonhepatic d isease group, did not significantly differ. Conclusions: The serum leptin level of patients with nonalcoholic liver dis eases is not elevated. On the other hand, the serum leptin level of patient s with alcoholic cirrhosis has been reported to be elevated. The difference in the serum leptin level of patients with nonalcoholic liver disease and that of patients with alcoholic cirrhosis may be due to a difference in fac tors such as the levels of cytokines or sex steroids, and/or nutrition. Fur thermore, it is Likely that leptin is cleared in part by the portosystemic circulation through the liver.