Reversal of Biological Clock Restores Vision In Old Mice

John Trumpian shares a report from SciTechDaily: Harvard Medical School scientists have successfully restored vision in mice by turning back the clock on aged eye cells in the retina to recapture youthful gene function. The team's work, described today in Nature, represents the first demonstration that it may be possible to safely reprogram complex tissues, such as the nerve cells of the eye, to an earlier age. In addition to resetting the cells' aging clock, the researchers successfully reversed vision loss in animals with a condition mimicking human glaucoma, a leading cause of blindness around the world. The achievement represents the first successful attempt to reverse glaucoma-induced vision loss, rather than merely stem its progression, the team said. If replicated through further studies, the approach could pave the way for therapies to promote tissue repair across various organs and reverse aging and age-related diseases in humans. Sinclair and colleagues caution that the findings remain to be replicated in further studies, including in different animal models, before any human experiments. Nonetheless, they add, the results offer a proof of concept and a pathway to designing treatments for a range of age-related human diseases. For their work, the team used an adeno-associated virus (AAV) as a vehicle to deliver into the retinas of mice three youth-restoring genes -- Oct4, Sox2 and Klf4 -- that are normally switched on during embryonic development. The three genes, together with a fourth one, which was not used in this work, are collectively known as Yamanaka factors. The treatment had multiple beneficial effects on the eye. First, it promoted nerve regeneration following optic-nerve injury in mice with damaged optic nerves. Second, it reversed vision loss in animals with a condition mimicking human glaucoma. And third, it reversed vision loss in aging animals without glaucoma.

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