Vitamin-D3 (Α-1, 25(OH) 2D3) Protects Retinal Pigment Epithelium from Hyperoxic Insults

PURPOSE. Oxidative stress affects the retinal pigment epithelium (RPE) leading to development of vascular eye diseases. Cholecalciferol (VIT-D) is a known modulator of oxidative stress and angiogenesis. This in vitro study was carried out to evaluate the protective role of VIT-D on RPE cells incubated under hyperoxic conditions. METHODS. Cadaver primary RPE (PRPE) cells were cultured in hyperoxia (40% O-2) with or without VIT-D (alpha-1, 25(OH) 2D3). The functional and physiological effects of PRPE cells with VIT-D treatment were analyzed using molecular and biochemical tools. RESULTS. Vascular signaling modulators, such as vascular endothelial growth factor (VEGF) and Notch, were reduced in hyperoxic conditions but significantly upregulated in the presence of VIT-D. Additionally, PRPE conditioned medium with VIT-D induced the tubulogenesis in primary human umbilical vein endothelial cells (HUVEC) cells. VIT-D supplementation restored phagocytosis and transmembrane potential in PRPE cells cultured under hyperoxia. CONCLUSIONS. VIT-D protects RPE cells and promotes angiogenesis under hyperoxic insult. These findings may give impetus to the potential of VIT-D as a therapeutic agent in hyperoxia induced retinal vascular diseases.