Researchers have restored vision in old mice and in mice with damaged retinal nerves by resetting some of the thousands of chemical marks that accumulate on DNA as cells age. The work, published on 2 December in Nature1, suggests a new approach to reversing age-related decline, by reprogramming some cells to a ‘younger’ state in which they are better able to repair or replace damaged tissue.
“It is a major landmark,” says Juan Carlos Izpisua Belmonte, a developmental biologist at the Salk Institute for Biological Studies in La Jolla, California, who was not involved in the study. “These results clearly show that tissue regeneration in mammals can be enhanced.”
But researchers also caution that the work has so far has been carried out only in mice, and it remains to be seen whether the approach will translate to people, or to other tissues and organs that are ravaged by time.
Visionary approach
Ageing affects the body in myriad ways — among them, adding, removing or altering chemical groups such as methyls on DNA. These ‘epigenetic’ changes accumulate as a person ages, and some researchers have proposed tracking the changes as a way of calibrating a molecular clock to measure biological age, an assessment that takes into
account biological wear-and-tear and can differ from chronological age.
That has raised the possibility that epigenetic changes contribute to the effects of ageing. “We set out with a question: if epigenetic changes are a driver of ageing, can you reset the epigenome?” says David Sinclair, a geneticist at Harvard Medical School in Boston, Massachusetts, and a co-author of the Nature study. “Can you reverse the clock?
posted by f.sheikh