A recent study conducted by School of Medicine researcher Saul Villeda found that that injection of blood from young mice into older mice reversed certain aging effects, especially those related to cognitive learning and memory.

Villeda used a method known as heterochronic parabiosis, connecting the circulatory systems of an old and a young mouse to allow their blood to combine. He found that the number of stem cells in the brains of the treated older mice increased and that there was a 20 percent increase in neural connections between their brain cells.

The young blood “topped up” levels of key chemical factors that normally decline in the blood as the mice age. The researchers have not determined exactly what chemical factors in the blood cause the anti-aging effect.

To see if the physical changes led to behavioral modifications, Villeda employed a memory test using a water maze and found that the treated older mice performed at same level as young mice, while untreated old mice consistently made mistakes.

Villeda presented the research, which built on previous findings, at the annual meeting for the Society of Neuroscience in New Orleans on Oct. 17. The previous findings showed the effect in reverse—younger mice that were injected were the blood of older mice begun to age more rapidly—and were published science journal Nature in September 2011. The latest findings have yet to be published in a peer-reviewed journal.

While this research has yet to be translated to humans, Villeda is confident that there is a possibility in the future for humans to reverse the signs of aging and other diseases such as Alzheimer’s and Parkinson’s.

“Do I think that giving young blood could have an effect on a human? I’m thinking more and more that it might,” Villeda said in an interview with The Guardian.

–Natasha Weaser