Role of advanced glycation end product receptors in the pathogenesis of diabetic retinopathy

Problem: Advanced glycation end products (AGEs) and the interaction with their receptors (RAGE) play an important role in the pathogenesis of diabetic retinopathy (DR). Our study investigated whether serum soluble (s) RAGE (sRAGE) could serve as a prognostic tool for identifying the susceptibility to DR. Moreover, we examined the association between soluble forms of vascular cell adhesion molecules (sVCAM-1), nitric oxide (NO) and sRAGE levels in serum and the severity of DR. Methods: Circulating levels of sRAGE, sVCAM-1, and NO were examined in 37 type 2 diabetic patient and 20 age-matched healthy nondiabetic subjects using ELISA. The diabetic subjects were categorized as patients without retinopathy, patients with nonproliferative DR (NPDR), and patients with proliferative DR (PDR). Results: Serum sRAGE levels were significantly lower in patients with NPDR and PDR than in healthy controls and in those without retinopathy (1331.13 +/- 126.13, 934.87 +/- 66.27 vs. 1712.69 +/- 167.3, 1833.1 +/- 153.06 pg/ml, respectively, P <.05). Serum sVCAM-1 and NO were significantly higher in diabetic patients (1310.215 +/- 54.712 vs. 616.55 +/- 12.9 ng/ml and 96.432 +/- 0.864 vs. 28.78 +/- 5.88 mu mol/l, respectively, P <.05) and were positively associated with the severity of DR. Conclusions: The results indicate that sRAGE is an endogenous protection factor against the occurrence of accelerated DR. (C) 2011 Elsevier Inc. All rights reserved.