Soluble leptin receptors and serum leptin in end-stage renal disease: relationship with inflammation and body composition

Background Elevated serum leptin (S‐leptin) levels have been reported in patients with end‐stage renal disease (ESRD). Apart from the decreased glomerular filtration rate (GFR), body composition and inflammation may affect leptin levels in ESRD. Leptin circulates both free of and bound to soluble leptin receptors (sOB‐R), which are the main determinants of leptin activity and have not been described in ESRD until now. Design To analyze the association between S‐leptin, sOB‐R, and inflammation and body composition, we studied 149 (62% males) normal weight (BMI 24·7 ± 0·4 kg m−2) ESRD patients (51 ± 1 years old) shortly before the start of dialysis (GFR 7·0 ± 0·2 mL min−1). sOB‐R and plasma interleukin‐6 (IL‐6; n= 113) levels were evaluated using ELISA, S‐leptin using RIA, and body composition was assessed by X‐ray absorptiometry (n = 139). Forty‐one healthy subjects age (51 ± 1 years), BMI (23·6 ± 0·5 kg m−2) and gender‐matched (59% males) were used as controls. Results Median S‐leptin was higher in the ESRD patients (10·0 ng mL−1) compared with the controls (3·9 ng mL−1) (P