The role of serum apelin in diabetic patients with retinopathy

ObjectiveThe aim of this work is to study serum apelin in patients with diabetic retinopathy and its possible pathophysiological role in such patients.BackgroundDiabetic retinopathy is the most common microvascular complication of diabetes, and it remains a leading cause of blindness and visual impairment in the working-age population in the developed world. Apelin is a peptide isolated from bovine stomach extracts that acts as an endogenous ligand for the previously orphaned G protein-coupled receptors (angiotensin 1-related putative receptors). Apelin has been recognized as a factor promoting angiogenesis, but its role in the development of proliferative diabetic retinopathy (PDR) has not been fully examined.Materials and methodsSixty patients were included in the study and classified into three groups. Group 1, the control group, included individuals without diabetes mellitus (10 patients), group 2 included patients with diabetes mellitus but without retinopathy (20 patients), and group 3 included patients classified into two subgroups: group 3a, which included patients with nonproliferative diabetic retinopathy (NPDR) (15 patients), and group 3b, which included patients with PDR (15 patients).ResultsApelin was significantly higher among patients with diabetes without retinopathy, NPDR, and PDR than the control group (P < 0.001); the mean value of apelin was significantly higher in patients with PDR than in those with diabetes without retinopathy (P < 0.05). Also, the mean value of apelin was significantly higher in patients with PDR than NPDR (P < 0.001).ConclusionSerum apelin was significantly higher in patients with PDR compared with those without nonproliferative retinopathy and in those with diabetes without retinopathy, and apelin plays a role in the development of PDR. Ischemic retinopathy could be trated with Inhibition of the apelinergic system. Serum apelin correlated significantly with serum creatinine in patients with retinopathy, which may indicate the role of apelin in diabetic nephropathy.