U.S. scientists have discovered that older mice become more energetic, stronger and have better memory when injected with the blood of young mice.
Researchers at Harvard University and the University of California, San Francisco, carried out their experiments on animals whose ages were equivalent to humans in their 20s and 60s.
They believe the blood of the younger mice has a protein called GDF11, which also is found in human blood. They say this protein appears to decline with age.
The doctors say they hope their research on mice can one day be used to treat human sufferers of diseases that affect the elderly, including dementia and Alzheimer's. But they caution people against trying this blood experiment at home.
The study appears in two journals -- Nature Medicine and Science.