Cellular reprogramming reverses signs of aging

Graying hair, crow's feet, an injury that's taking longer to heal than when we were 20—faced with the unmistakable signs of aging, most of us have had a least one fantasy of turning back time. 

Now, scientists at the Salk Institute have found that intermittent expression of genes normally associated with an embryonic state can reverse the hallmarks of old age.

This approach, which not only prompted human skin cells in a dish to look and behave young again, also resulted in the rejuvenation of mice with a premature aging disease, countering signs of aging and increasing the animals' lifespan by 30 percent. The early-stage work provides insight both into the cellular drivers of aging and possible therapeutic approaches for improving human health and longevity.

"Our study shows that aging may not have to proceed in one single direction," says Juan Carlos Izpisua Belmonte, a professor in Salk's Gene Expression Laboratory and senior author of the paper appearing in the December 15, 2016 issue of Cell. "It has plasticity and, with careful modulation, aging might be reversed."

As people in modern societies live longer, their risk of developing age-related diseases goes up. In fact, data shows that the biggest risk factor for heart disease, cancer and neurodegenerative disorders is simply age.

One clue to halting or reversing aging lies in the study of cellular reprogramming, a process in which the expression of four genes known as the Yamanaka factors allows scientists to convert any cell into induced pluripotent stem cells (iPSCs).