Last year, the protein, called growth differentiation factor 11 (GDF11), was found to have a restorative effect on mouse hearts. If it does a similar job in humans, it could have huge potential for treating a wide-range of age-related diseases, say the researchers behind the latest work.
The idea that an infusion of young blood could regenerate ageing bodies was explored several years ago when the circulatory systems of old mice were physically connected to those of young animals, as if they were conjoined twins. This rejuvenated the stem cells in the bone marrow of the older mice that replenish their blood, and led to a wave of studies comparing the blood of old and young mice to try and identify the youth-giving substance.[MORE](http://www.newscientist.com/article/dn25516-blood-protein-rejuvenates-brain-and-muscle-in-old-mice.html#.U2j7MvldV2A)