Healing of ischemic injury in the retina

Neuro- and retinal degenerative diseases, including Alzheimer's, stroke, age-related macular degeneration, and central retinal artery occlusion, rob millions of their independence. Studying these diseases in human retinas has been hindered by the rapid loss of neuronal activity after death. While some CNS activity has been restored postmortem, synchronized neuronal transmission beyond 30 min has remained elusive. We overcome this barrier by reviving and sustaining light signal transmission in human retinas recovered up to 4 hours after death and stored for up to 48 hours. We also introduce infrared-based ex vivo imaging for precise sampling, a closed perfusion system for drug testing, and an ex vivo ischemia-reperfusion model in mouse and human retina. This platform enables testing of neuroprotective and neurotoxic effects of drugs targeting oxidative stress and glutamate excitotoxicity. Our advances question the irreversibility of ischemic injury, support preclinical studies in vision restoration, offer insights into treating CNS ischemia, and pave the way for human donor eye transplantation.