Serum leptin concentrations and their relation to metabolic abnormalities in human sepsis

Circulating leptin concentrations are raised in animal models of inflammati on and sepsis. The purpose of this study was to determine the effect of sep sis on serum leptin Concentration in humans and to examine the relationship between leptin and the metabolic consequences of sepsis. Resting energy ex penditure, insulin sensitivity, and fasting serum leptin, plasma insulin, a nd cortisol concentrations were measured in 20 subjects with intra-abdomina l sepsis and 20 healthy control subjects,before and during a 2-h period of euglycemic hyperinsulinemia. Fasting serum leptin concentrations were simil ar in septic and control subjects. In simple regression analysis, serum lep tin concentrations correlated significantly with percent body fat in both s eptic patients (r = 0.64, P < 0.005) and healthy subjects (r = 0.75, P < 0. 0001). Multiple regression analyses additionally indicated that percent bod y fat, fasting plasma insulin, and plasma cortisol, but not sepsis, were si gnificant and independent determinants of serum leptin concentration. No re lationship between leptin and resting energy expenditure or insulin sensiti vity was identifiable. A major metabolic role for leptin in human sepsis th erefore appears unlikely.