Increased serum endogenous secretory receptor for advanced glycation end-product (esRAGE) levels in type 2 diabetic patients with decreased renal function

Abstract

Background The binding of advanced glycation end-products (AGEs) to their receptor for AGEs (RAGE) may play an important role in the development of diabetic vascular complications. Recently, soluble RAGE (sRAGE) has been identified as an alternative splicing form of RAGE. Furthermore, administration of sRAGE improved atherosclerosis in type 2 diabetic mice. Objective The objective of the present study is to investigate the role of endogenous secretory RAGE (esRAGE) as a biological marker for type 2 diabetic nephropathy, and also to determine whether serum esRAGE levels are associated with serum AGEs [including Nɛ–(carboxymethyl) lysine–protein adducts (CML) and pentosidine] levels. Materials and methods Serum esRAGE levels were examined in 107 type 2 diabetic patients including those on hemodialysis (HD). Diabetic patients were divided into three groups as follows: Group A [patients without nephropathy, i.e. normoalbuminuric stage (AER < 30 μg/mg creatinine)], Group B [patients with nephropathy (AER > 30 μg/mg creatinine) but excluding HD patients], and Group C (HD patients). Results Serum esRAGE and AGEs (including CML and pentosidine) levels in Group C were significantly higher than in Group A or B. In single linear univariate correlation, serum esRAGE levels were correlated using body mass index (BMI), duration of diabetes, and serum creatinine, high-density lipoprotein (HDL)-cholesterol and AGEs (including CML and pentosidine) levels. Furthermore, in stepwise multivariate regression analysis, the levels of serum creatinine and duration of diabetes were independently associated with serum esRAGE levels. Conclusion Serum esRAGE levels are associated with the severity of renal dysfunction and duration of diabetes in type 2 diabetic patients.