When fast-aging elderly mice with a usual lifespan of
21 days were injected with stem cells from younger mice at the Institute for Regenerative Medicine in
Pittsburgh, the results were staggering. Given the injection approximately four days before they were expected to die, not only did the elderly mice live - they lived threefold their normal lifespan, sticking around for 71 days. In human terms, that would be the equivalent of an 80-year-old living to be 200.