Has the day come when a shot of young stem cells could help an aging senior citizen regain energy, appear younger and wipe away the years?
The question is a fair one, because scientists at the University of Pittsburgh School of Medicine appear to have accomplished this in rapidly aging mice. Senior investigators Johnny Huard and Laura Niedernhofer and their team injected the mice with stem/progenitor cells from the muscles of younger, healthy mice, and presto! The rapidly aging rodents became healthier, more youthful in appearance and even lived longer. Details are published in the Jan. 3 edition of Nature Communications.
"In order to stay healthy and functional, your stem cells are really important," Niedernhofer told CBS News about the finding. "We've got to find a way to replace them or improve their function. I think that will be a key goal for staving off a lot of aging-related diseases."
The answer to whether humans can benefit, however, may not be addressed for a while. Researchers believe that they may be able to eventually use the same technique to reverse aging-related biological declines in people with a shot of youthful stem/progenitor cells. First, however, they'll have to replicate their results in further animal trials and, ultimately, in human testing, and that's a long way off. They'll also have to do testing in older mice--not just the type of mice used in the trial, which were bred to have progeria, a disorder that causes premature aging.
Still, the results are pretty tantalizing. Stem cell dysfunction, like poor replication and differentiation, has been shown in previous research to exist in various tissues in old age, the researchers note. They reinforced this with the first part of their research, determining that stem/progenitor cells from muscles of progeria mice were small in number, didn't replicate much or differentiate well, and they couldn't repair damaged muscle easily, just like similar cells found in super old mice.
Next, came the actual tests with progeria mice, which usually die between 21 and 28 days of age, dealing with slow movement, trembling and shriveled muscles in their hind legs. So at day 17, before aging accelerated to that point, they injected the mice in the stomach with stem/progenitor cells from the muscles of their younger and healthier counterparts. Interestingly, those mice then began to age more slowly, grew normally and developed new blood vessels in the brain and muscles, even though the stem cells didn't migrate from their injection site. Some lived older than 66 days, more than double their typical life span.
Even in a petri dish, the treatment showed promise. Young stem cells placed near progeria stem cells helped improve the latter cells' function, even though the cells didn't touch, the researchers said.
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