New York: Stem cells in an old tissue are still able to perform regenerative functions, provided they receive appropriate chemical signals, according to a new study.

Earlier studies have shown that when old tissue is placed in an environment of young blood, the stem cells behave as if they are young again.

A team of bio-engineers at California University, led by Irina Conboy, identified two key pathways that determine how well adult stem cells repair and replace damaged tissue.

They then tweaked how those stem cells reacted to those biochemical signals to revive the ability of muscle tissue in old mice to repair themselves, nearly as well as the muscle in the mice's much younger counterparts.

“We are constantly falling apart, but we don't notice it much when we're young because we're always being restored. As we age, our stem cells are prevented, through chemical signals, from doing their jobs,” Conboy said.

Because the findings bear on adult stem cells in existing tissue, this approach to rejuvenating degenerating muscle, bypasses medico-ethical complications associated with tissues from embryonic stem cells.

“We are one step closer to having a point of intervention where we can rejuvenate the body's own stem cells so we don't have to suffer from some of the debilitating diseases associated with ageing,” said the study's co-author, Morgan Carlson.

The findings of the study were published Sunday in an advanced online issue of the journal Nature.