Updated

The secret to eternal youth may come in the form of stem cell injections, U.S. scientists claimed.

Researchers from the University of Pittsburgh made the discovery after breeding mice with progeria syndrome, which causes rapid aging, and injecting them with stem-cell-like cells derived from young, healthy rodents.

They found that the shots reversed the aging process and that the mice lived three times longer than expected.

As well as extending life, the treated mice appeared to benefit from better health, increased muscle strength and a better flow of blood to the brain.

"Our experiments showed that mice that have progeria, a disorder of premature aging, were healthier and lived longer after an injection of stem cells from young, healthy animals," Dr. Laura Niedernhofer said. "That tells us that stem cell dysfunction is a cause of the changes we see with aging."

The power of young, healthy cells was seen in culture dish experiments when researchers placed them close to, but not touching, unhealthy cells -- and the sick, aging cells performed better.

"This leads us to think that healthy cells secrete factors to create an environment that help correct the dysfunction present in the native stem cell population and aged tissue," Niedernhofer added.

The findings were published in the journal Nature Communications.