This Sunday a trio of landmark studies were published each discussing an aspect of a wider picture: reversing aging in the muscles and brains of old mice simply by transfusing blood coming from younger mice. The effect is credited to a key protein found in much higher concentration in the blood of younger mice. So far, the findings are niched to a particular breed of mice, but if the results can be replicated with other strains as well, then trial on humans might not be far off.
It all started when researchers at Harvard University found that a protein called GDF11 could cause a mouse heart thickened with age to revert to a youthful state. Now, other groups have found that these effects extend that work to the mouse brain and muscle.
In one study, Amy Wagers, a professor of stem cell and regenerative biology at Harvard University, and colleagues joined the blood vessels of young and old mice together so that they might effectively share their blood – a procedure called parabiosis. They measured profound changes to muscle stem cells in the older mice that made the cells appear more youthful. Structural changes to the muscles were also recorded.
Next, they injected the protein that had been shown to rejuvenate hearts into the older mice. The primary effect of GDF 11 appears to be increased blood flow, and it was noted that the older mice who had elevated concentrations of GDF 11 were able to repair muscle damaged after injury. Although some individual mice did not change much, on average, the treated mice could run nearly twice as long on a treadmill as older mice not given the protein. The protein had no effect when injected into younger mice, as reported in the journal Science.
Better muscles, better brain, better bodies
Then in a second study, Dr. Lee Rubin, director of translational medicine at the Harvard Stem Cell Institute, found that after parabiosis, the older mice had an increase in the branching network of blood vessels in the brain and in the rate of creation of new brain cells. It also bolstered function in the region of the brain involved with olfaction, which is how we interpret smells.
An important caveat about the research that needs to be mentioned, however, is that it was done on a particular strain of mouse that is inbred. The protein’s effect needs to be tested on more genetically diverse strains as well before any thought can be given about extending the work to human clinical trials.
In the third study published in the journal Nature Medicine, researchers from the University of California, San Francisco and Stanford used parabiosis to search for changes in gene activity in the brain that might help point to how young blood had its effects. Interesting enough, the researchers found key changes in the gene activity involved in the connectivity of brain cells in a region called the hippocampus – the part of the brain responsible for memory storage and retrieval.
When the Californian researchers transfused blood from young mice to older ones, the animals experienced an improvement in age-related memory tasks, like locating an underwater platform and remembering environments where they had a bad experience (nasty electrical shock).
While, all three studies – though they differ in their approach – seem to point in the direction that GDF 11 has key rejuvenating benefits, it’s still too early to make any guesses. More work needs to be made and until then, it’s a good idea not to try transfusing all of you blood with that of your niece.