February 20, 2005
When Hooking Up Is Good For You
From Eurekalert, an observation on May-December conjunctions...
Any older person can attest that aging muscles don't heal like young ones. But it turns out that's not the muscle's fault. A study in the Feb. 17 issue of Nature shows that it's old blood that keeps the muscles down.
The study, led by Thomas Rando, MD, PhD, associate professor of neurology and neurological sciences at the Stanford University School of Medicine, built on previous work showing that old muscles have the capacity to repair themselves but fail to do so.
Rando and his group studied specialized cells called satellite cells, the muscle stem cells, that dot muscle tissue. These normally lie dormant but come to the rescue in response to damaged muscle-at least they do in young mice and humans.
In older mice the satellite cells hold the same position, but are deaf to the muscle's cry for help.
In the Nature study, Rando and his group first attached old mice to their younger lab-mates in a way that caused the two mice to share a blood supply. They then induced muscle damage only in the older mice.
Bathed in the presence of younger blood, the old muscles healed normally. In contrast, when old mice were connected to other old mice they healed slowly.
As Randall Parker observes, we may be dealing with a two edged sword here.
There is a potential bright side to this report: If blood could be made young again then possibly cells thoroughout the body in many tissue types would act young again...However, there is a less optimistic interpretation to this result: The body may have evolved to produce stem cell growth suppressor compounds as the body ages in order to suppress cell divisions that could produce cancer cells. So blood that causes old stem cells to grow and repair tissue more vigorously might increase the risk of cancer.
Clearly, we have a long slog ahead of us before we reach the proficiency level of Dr. McCoy's saltshakers.
posted by Justin on 02.20.05 at 07:33 PM
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