Dr. Kennedy’s research focuses on metabolic regulation and ion transport in the retinal pigment epithelium (RPE). The RPE is an epithelial monolayer situated between the sensory retina and its choroidal blood supply. It sustains retinal photoreceptors by performing typical epithelial functions such as water transport, regulation of extracellular ion activity and transepithelial solute exchange. Notably, the retina is the most metabolically active mammalian tissue with photoreceptors exhibiting the highest O2 demand of any cell. All of the O2 delivered to the photoreceptors comes from the choroidal circulation and must thus pass through the RPE. Photoreceptors are critically dependent on this O2 delivery and even small decrements in systemic oxygenation can lead to measurable changes in vision. The RPE has been shown to express the protein hemoglobin. A current research focus is the possible involvement of hemoglobin in oxygen delivery to photoreceptors through the RPE monolayer.
