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SALT LAKE CITY — A team of researchers at the University of Utah's John A. Moran Eye Center have succeeded in reviving neurons and communication in human donor eyes, which they said could transform brain and vision research.
This study, they said, will benefit research on other neuronal tissues in the central nervous system and help researchers better understand neurodegenerative diseases, like macular degeneration.
"We were able to wake up photoreceptor cells in the human macula, which is the part of the retina responsible for our central vision and our ability to see fine detail and color," said Moran Eye Center scientist Fatima Abbas, lead author of a study published on Wednesday in Nature.
Abbas said age-related macular degeneration, which leads to blindness, affects about 10% of the population.
"Just being able to take these donor eyes and understand how the retina works in humans, specifically, and what's going wrong in these diseases is a huge thing," Abbas said.
She explained that in donor eyes obtained up to five hours after the death of the donor, cells respond to bright light, colored light and dim light flashes, but they could not communicate with other retina cells. Researchers determined that this loss of communication stemmed from oxygen deprivation.
To solve this issue, they procured donor eyes within 20 minutes of a donor's death and designed a transportation unit that could restore oxygenation and nutrients to donor eyes.
Frans Vinberg, a Moran Eye Center scientist, said they were able to make retinal cells communicate as they do in living eyes.
"Past studies have restored very limited electrical activity in organ donor eyes, but this has never been achieved in the macula, and never to the extent we have now demonstrated," Vinberg said.
He said people are living longer now, and that means more people are dealing with retinal neurodegenerative diseases that lead to blindness.
"If these neurons die, it's hard to imagine how you can revive them," he said.
Vinberg said this approach, using human donor eyes, reduces research costs compared to using nonhuman primates, and also ensures results will apply to humans. He said mice are often used for vision research, but they do not have a macula. Through this study they established an approach to reviving the neural tissue in the back of the eye.
"The scientific community can now study human vision in ways that just aren't possible with laboratory animals. ... We hope this will motivate organ donor societies, organ donors and eye banks by helping them understand the exciting new possibilities this type of research offers," Vinberg said.
He said they produced retinal patches that are fully functional.
"We are basically encouraging other scientists to start to obtain human neural tissue and start to really study and understand how human neurons work," Vinberg said.
Scripps Research associate professor Dr. Anne Hanneken, who is also a retinal surgeon, said this ability to create viable patches of human retinal tissue will help treat blinding diseases.
"Going forward, we'll be able to use this approach to develop treatments to improve vision and light signaling in eyes with macular diseases, such as age-related macular degeneration," Hanneken said.
A University of Utah Health press release explained that this study joins others that question "the irreversible nature of death," since death is partly defined with a loss of neuronal activity.