The DNA of old muscle stem cells was repaired; muscle fibers and cell structures called mitochondria morphed into healthier, more youthful versions; grip strength improved; and the mice were able to run on treadmills longer than their untreated counterparts.
The protein used in the study, called GDF11, was already known to reduce age-related heart enlargement, which is characteristic of heart failure. But [Harvard researchers Amy] Wagers said the new work shows that GDF11 has a similar age-reversal effect on other tissue, in particular the skeletal muscle and brain.
"That means that this protein is really acting in somewhat of a coordinating way across tissues," she said , and that drugs could be developed to target a "single common pathway" seen in a variety of age-related dysfunctions, including muscle weakness, neurodegeneration, and heart disease.
The tranfusions also stimulated the growth of neurons in regions of the brain responsible for memory formation and a sense of smell. These mice were better able to distinguish between different odors, and remember how to navigate a maze, reversing declines in these abilities normally seen in the course of again.
But it is reasonable to think this won't be some sort of silver bullet. Here is one important caveat, as noted in the New York Times:
But scientists would need to take care in rejuvenating old body parts. Waking up stem cells might lead to their multiplying uncontrollably.
"It is quite possible that it will dramatically increase the incidence of cancer," said Irina M. Conboy, a professor of bioengineering at the University of California, Berkeley. "You have to be careful about overselling it."
