Which is the Role of Leptin on Patients in the End Stage of Renal Disease?

Abstract

family of cytokines, related to diminished food intake. Since leptin is mainly secreted by adipose tissue, serum leptin levels are directly proportional to adipocyte mass. Apart from metabolism, leptin has systemic effects including regulation of angiogenesis, wound healing, lipolysis, blood pressure homeostasis, reproduction, hematopoiesis and immune function [2,3] . The current studies provide evidence that the real role of leptin on the patients in end stage of renal disease is complicated rather than clear. LEPTIN, INFLAMMATION, MALNUTRITION AND INSULIN RESISTANCEIt has been already recognized that a substantial number of patients with end-stage renal disease have serologic evidence of an activated inflammatory state [4] . Previously, the leptin receptor has been identified on endothelial cells, and leptin has been reported to promote both angiogenesis and inflammation [5] . Leptin modifies the systemic inflammatory response and the inflammatory microenvironement in renal disease may be associated with elevated expression of leptin gene [6] . However, there is a discrepancy for the relationship of leptin levels with chronic inflammation and it has been supported that leptin may be a negative acute phase protein in chronic hemodialysis patients [7] . On the other hand, leptin suppresses appetite and increases energy expenditure, playing a homeostatic role in the regulation of food intake and in maintaining body composition in general population [8] . In patients with end-stage renal disease malnutrition and hypoalbuminemia are common and powerful predictors of morbidity and mortality in this population [9] . One potential relationship between malnutrition and inflammation in renal disease patients is appetite suppression and the link between inflammation and anorexia may be through the leptin [10] . However, it has been already supported that inflammation is unlikely to reduce appetite causing malnutrition in dialysis patients through a leptin-mediated mechanism, because leptin is a negative rather than a positive acute phase protein in this population of patients [7] . Also, recent study reported that leptin levels were elevated in ESRD patients with normal and mild malnutrition, ABSTRACTLeptin is a small peptide hormone (16 kDa), a product of the obesity gene (Ob), and is mainly synthesized and secreted by adipocytes.In this review paper the main points of the leptin role on the end stage of renal disease is out lined.