Role of nerve-vascular interaction by amacrine cells in intractable ocular inflammatory diseases

Yoshihiko Usui is a researcher based in the Department of Ophthalmology at Tokyo Medical University, Japan, who is also a research associate of the Scripps Research Institute (TSRI) in the US. His work surrounds the area of ophthalmology, with research projects such as 'Role of nerve-vascular interaction by amacrine cells in intractable ocular inflammatory diseases' and 'Cytokine profiles in intraocular fluids of patients with acute retinal necrosis' and 'Neurovascular crosstalk between interneurons and capillaries is required for vision' which look at vision and eye disease. Usui's work is funded by KAKEN Grants-in-Aid for Scientific Research. Usui is involved in a recent study surrounding the interactions between nerve cells and blood vessels in the eye to prevent disease. Interactions between neurons, vasculature and glia within neurovascular units are critical for maintenance of the retina, as well as other tissues of the nervous system. The team looked at amacrine cells and horizontal cells, which are a subset of retinal interneurons that play a role in adjusting electrical signals to the brain from the photoreceptors after they have been stimulated by light photons. Horizontal cells provide inhibitory feedback for cone-driven pathways, while amacrine cells have diverse physiologies and exhibit multifaceted connectivity throughout the inner plexiform layer (IPL) that allows them to pre-process and integrate visual signals and interpose temporal cues. The researchers decided to focus on these cells because they seem to wrap themselves around the blood vessels of the intermediate layer. The researchers wanted to discover if the neurons were altering the way vasculature forms and behaves. To ascertain this, they 'knocked out' the production of a chemical called VEGF in the amacrine and horizontal cells of mice before they were born. VEGF acts to prompt new blood vessel growth, which brings more oxygen to the area. The researchers discovered that these mice never developed normal blood vessels in the intermediate layer, which led the photoreceptors to degenerate and resulted in severe vision loss.