Having young blood keeps your bones healing faster

Over the past few years, researchers have reversed muscle atrophy, memory loss, heart degradation and some of the effects of cognitive decline by pumping the blood of young mice into old mice. The results from these animal experiments were so intriguing that last year a team at Stanford University began the ultimate rejuvenation trial: giving blood plasma from under 30s to people with Alzheimer's. Results are expected next year.

Now, Benjamin Alman, a professor of surgery at the Hospital for Sick Children in Toronto, Canada, and his colleagues have tested young blood's ability to heal bones.

The team surgically joined the circulatory systems of mice of various ages, in a procedure known as parabiosis. Fractured shin bones of old mice healed faster and better when the rodents were joined to young mice than to mice their own age.