Retinol binding protein 4 concentrations are influenced by renal function in patients with type 2 diabetes mellitus

Retinol binding protein 4 (RBP-4), a newly discovered adipocytokinc, has been involved in glucose and lipid metabolism. We assess the impacts of renal function on plasma RBP-4 levels in patients with type 2 diabetes mellitus with a wide range of nephropathy. Plasma RBP-4 levels were measured using the enzyme immunoassay method in 38 type 2 diabetes mellitus patients with nephropathy and were compared with those in 20 patients with normoalbuminuria. The levels of plasma RBP-4 were increased by 1.4- and 3.3-fold in patients with renal disease with macroalbuminuria (P = .04) and end-stage renal disease (plasma creatinine level >2.0 mg/dL) (P < .0001) compared with those in patients with normal renal function. In addition, RBP-4 levels were correlated with the creatinine level and 24-hour creatinine clearance (Ccr) on simple and multiple regression analyses in all patients. Furthermore, in patients having Ccr of more than 60 mL/min, RBP-4 levels were correlated with the homeostasis model assessment (HOMA)-r index and triglyceride (TGL) both on simple and multiple regression analyses. Interestingly, in patients having Ccr of less than 60 mL/min, RBP-4 levels were not correlated with the HOMA-r index and TGL on simple regression analysis. The RBP-4 concentrations are influenced by renal function in type 2 diabetes mellitus patients. In addition, RBP-4 levels were correlated with HOMA-r and TGL in diabetic subjects without end-stage renal disease. (C) 2008 Elsevier Inc. All rights reserved.