Mammal eyes don’t heal the way a zebrafish’s does: once retinal cells die, the loss is usually permanent, which is why conditions like retinitis pigmentosa and macular degeneration are so hard to reverse. A team at KAIST in South Korea has now shown why — and how to switch the repair ability back on, at least in mice.
The culprit is a protein called Prox1. After retinal injury, Prox1 moves from neurons into support cells called Müller glia and effectively locks them, stopping them from behaving like the regenerative, stem-like cells they are in fish and amphibians. When the researchers blocked that transfer with an anti-Prox1 antibody delivered by a harmless virus (AAV), the Müller glia started regenerating retinal neurons and vision loss was delayed — an effect that lasted six months and beyond, the first long-term neural retina regeneration seen in a mammal. They also found the same Prox1 build-up in a human retinitis pigmentosa patient’s retina, hinting the mechanism carries over to us.
Important caveat: this was done in mice, not people. It is a preclinical result — promising, but years of safety work and human trials away. The viral headline version (“scientists unlocked the secret to eye repair”) overstates where this actually is. Still, as a proof of concept that a mammal retina can be coaxed into regenerating, it is a real step.
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