Microscopic images show a striking contrast: muscles restored by stem cells from old mice with high glutathione levels look significantly better than those where the antioxidant was lacking.
Researchers at UCLA, led by Dr. Thomas Rando of the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, found that restoring glutathione levels — a key antioxidant that protects cells from damage — rejuvenates old muscle stem cells.
According to a UCLA Health press release, with age, the muscle stem cell population in mice splits into two subgroups that differ in glutathione metabolism. Cells with high levels of the substance effectively participate in tissue repair, while those with low levels do poorly.
In young mice, stem cells remain homogeneous and highly efficient. Over the years, a second, less active population appears, and it is glutathione metabolism, according to scientists, that becomes the main factor in this division.
The team conducted experiments: adding a drug that increases glutathione levels to the population of 'weak' old cells allowed them to better repair muscle. Conversely, reducing glutathione in young cells made them behave like old ones.
The results were published in the peer-reviewed journal Cell Metabolism. Dr. Rando noted that if the functional youth of all stem cells can be preserved, tissue regeneration throughout life would become a reality.
The study was funded by the Glenn Foundation for Medical Research, the U.S. National Institutes of Health, and the Department of Veterans Affairs, as well as grants from Stanford University, the California Institute for Regenerative Medicine, and the Buck Institute.
The scientists emphasize that restoring glutathione opens the way to therapies that will help old tissues repair as effectively as young ones.
According to Rando, glutathione is one of the key factors determining what exactly goes wrong during aging.
Further tests of drugs and methods to increase levels of this antioxidant bring the development of practical approaches to improving tissue regeneration in the elderly closer.
