# Healing of ischemic injury in the retina

## TL;DR

Researchers revived light signal transmission in human retinas up to 48 hours after death, challenging the idea that ischemic injury is irreversible and opening new avenues for vision restoration.

## Contribution

The study introduces a method to sustain light signal transmission in postmortem retinas and develops a platform for drug testing and vision restoration research.

## Key findings

- Human retinas can transmit light signals up to 48 hours after death when properly preserved.
- A closed perfusion system and ischemia-reperfusion model were developed for drug testing in retinas.
- The findings suggest ischemic injury in the retina may be reversible, offering hope for vision restoration.

## Abstract

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.

Light signals in postmortem human retinas challenge that ischemic injury is irreversible and aid research to restore vision.