Plasma leptin levels in patients with kidney diseases of various etiologies

BACKGROUND: Leptin is a new hormone influencing food intake, energy expenditure and body weight. This protein is produced by adipocytes, exerts its effects on brain, endocrine pancreas and other organs by activating transmembrane receptors and is cleared from plasma mainly by the kidneys. The aim of our study was to compare plasma concentrations of leptin in our nephrological out-patients and controls. METHODS AND RESULTS: We examined 36 diabetic patients with various stages of nephropathy, 12 males with nephrotic syndrome due to membranous nephropathy, 15 dialysis patients and 11 controls. Leptin was assessed in plasma by ELISA. There was a significant difference between plasma levels of leptin in males and females (7.7 +/- 11.4 vs 17.6 +/- 17.3, p < 0.001) and in dialysis and non-dialysis patients (19.6 +/- 16.5 vs 10.7 +/- 14.5, p < 0.05). There was also a difference between dialysed and non-dialysed men (15.1 +/- 16.2 vs 5.9 +/- 9.2, p < 0.05). We found no difference between men with and without nephrotic syndrome and between BMI or age. There was a positive correlation of leptin with diabetic and non-diabetic women. There was positive correlation of P-leptin with serum creatinine in non-dialysed women (r = 0.68, p < 0.001) and a negative correlation with S-albumin in nephrotic men (r = -0.65, p < 0.05). CONCLUSIONS: Women have higher plasma leptin concentrations than men and dialysis patients have higher concentrations than non-dialysed patients. Apart from the positive correlation with S-creatinine in non-dialysed women. There was positive correlation with S-albumin in nephrotic men there were no correlations with renal function, BMI, age, S-cholesterol, S-triglycerides and S-albumin.