Leptin elimination in hyperleptinaemic peritoneal dialysis patients

Background. Elevated plasma concentrations of leptin, a hormone thought to regulate body composition by influencing food intake/metabolic rate, are pr evalent in renal failure patients. The mechanism for these increases is not knows, but evidence suggests that simple accumulation due to decreased eli mination is insufficient explanation. Methods. We studied the incidence of hyperleptinaemia in 28 end-stage renal disease patients treated with continuous ambulatory peritoneal dialysis (C APD), compared with body-mass-index-and sex-matched controls. Results were separated by gender because women have higher leptin concentrations than me n. Excretion of leptin and other substances in dialysis fluid was also stud ied. Results. Hyperleptinaemia was prevalent in women CAPD subjects, but not in men. Plasma leptin concentrations correlated strongly with the daily excret ion of leptin in dialysis fluid. Clearance of leptin in dialysis fluid was greater in men than women CAPD subjects. Single regression analysis found t hat fasting insulin, glucose content of dialysis fluid, plasma albumin, C-r eactive protein, erythropoietin dose, urinary creatinine clearance and plas ma beta(2)-microglobulin were not determinants of plasma leptin concentrati ons. Stepwise forward multiple regression, examining the dependence of plas ma leptin on body mass index, renal creatinine clearance, plasma albumin, d aily dialysis fluid glucose load, daily leptin in dialysis fluid, erythropo ietin dose and plasma C-reactive protein found only erythropoietin dose as a consistent negative predictor of plasma leptin concentrations. Conclusions. The results suggest that hyperleptinaemia of CAPD was due to p redisposing loss of renal elimination capacity combined with increased prod uction due to obesity (more prevalent in women subjects of this study) and potentially female gender.