More research is needed to discover whether young blood might also increase the life span of mice and what the implications for humans might be.
Two other reports appearing in Science from researchers at Harvard University found that exposing old mice to a protein present at high levels in the blood of young mice and people improved both brain and exercise capability. An earlier report by some of the same researchers linked injections of the protein to reversal of the effects of aging on the heart. ... What isn't known from all this research, said Buck Institute's Dr. [Brian] Kennedy, is whether young blood might also increase the life span of mice and, if so, what such implications for humans might be."