Three-dimensional spheroids of choroid-retinal vascular endothelial cells as an model for diabetic retinopathy: Proof-of-concept investigation.

Diabetic retinopathy (DR) is a primary microvascular complication of and a vision-threatening condition. Vascular endothelial growth factor (VEGF) induces neovascularization and causes metabolic damage to the retinal and choroidal vasculature in diabetic patients. Existing drug screening models and treatment strategies for DR need to be refined through the establishment of relevant pre-clinical models, which may enable development of effective and safe therapies. The present study discusses the development of an three-dimensional (3D) spheroid model, using RF/6A choroid-retinal vascular endothelial cells, to closely mimic the disease condition. Compact, reproducibly-sized, viable and proliferating RF/6A spheroids were fabricated, as confirmed by microscopy, live/dead assay, cell proliferation assay and histological staining. angiogenesis was studied by evaluating individual effects of VEGF and an anti-VEGF monoclonal antibody, Bevacizumab, and their combination on cellular proliferation and 3D endothelial sprout formation. VEGF stimulated angiogenic sprouting while Bevacizumab demonstrated a dose-dependent anti-angiogenic effect, as determined from the cellular proliferation observed and extent and length of sprouting. These investigations validated the potential of RF/6A spheroids in providing an alternative-to-animal, pathophysiologically-relevant model to facilitate pre-clinical and biomedical research related to DR.