Disorders in retinol metabolism as an important part in the pathogenesis of myopia

Abstract

Aim. Determination of changes in expression of lymphocyte surface receptors and concentrations of malonic dialdehyde and vitamin A in peripheral blood of patients with myopia as compared to healthy donors, and creation of a pathogenetic model. Methods. This study included 38 children with acquired moderate myopia without concurrent chronic diseases; 35 children constituted a control group. The children were 11 to 17 years old. The amount of lymphocytes expressing CD3, CD4, CD8, CD16, CD56, CD20, CD72, CD38, CD25, CD71, HLA-DR, CD95, CD54, and membrane immunoglobulins mIgM and mIgG was determined using the indirect immunofluorescence method with monoclonal antibodies. Concentrations of malonic dialdehyde (MDA) in blood and vitamin A in plasma were measured by traditional biochemical methods. Results. Patients with myopia had increased amounts of CD20-, CD54-, and CD95-positive lymphocytes. The observed immune disorders were secondary. The blood concentration of MDA was increased, and the vitamin A concentration was decreased in myopia patients compared to the control. Based on these data a pathogenetic model was proposed, in which disordered physiological regeneration of photoreceptor disks took the central place. The delayed absorption of pigment epithelial cells and impaired intracellular hydrolysis of their components result in activation of lipid peroxidation, formation of MDA, and damages of the vascular endothelium and scleral fibroblasts. The process of fibroblast remodeling is limited by influx of metabolites through the damaged endothelium, which induces synthesis of weak type V collagen with short chains. Conclusion. Pathogenetically substantiated therapy of myopia should be aimed at increasing the functional activity of pigment epithelial cells.