Adrenomedullin and Leptin Levels in Diabetic Retinopathy and Retinal Diseases

Abstract

Purpose: Proliferative and vascular retinal diseases are important cause of irreversible blindness. Consistent features of these diseases are endothelial dysfunction and angiogenesis. Adrenomedullin (ADM) is a multifunctional vasorelaxant peptide. Leptin is a recently discovered metabolic peptide that regulates energy metabolism in human. In the present study, we aimed to investigate the possible roles of adrenomedullin and leptin in the pathophysiology of diabetic and proliferative diseases. Methods: Ten patients with proliferative diabetic retinopathy (57.1 years, 5 female and 5 male) and 8 patients (51 years, 5 female and 3 male) with other retinal diseases including macular hole and epiretinal membrane were included in this study. All the patients had undergone pars plana vitrectomy for complications of the diseases. Vitreous samples were collected by vitreous tap during the vitrectomy. Adrenomedullin analysis was made by using reverse-phase high-performance liquid chromatography (HPLC). Leptin was measured by enzyme-linked immunosorbent assay (ELISA). Body mass index (BMI) [weight (kg)/height (m²)] was calculated for each group. The Mann-Whitney U test was used for statistics. Results: The age, gender ratio and BMI were not substantially different between the two groups. The mean vitreous adrenomedullin levels (63.9 ± 7.1 pmol/l) were significantly higher (p < 0.05) in group I than in group II (34.25 ± 3.0 pmol/l). Leptin levels in vitreous (4.54 ±1.6 ng/ml) were also significantly higher (p < 0.05) in patients with diabetic retinopathy than in those without diabetes (1.83 ± 0.5 ng/ml). Conclusion: Increased adrenomedullin and leptin levels in vitreous humor might be a possible newly associated factor in the course of vascular and proliferative retinal diseases.