Aging skin goes through a number of predictable changes. Skin loses collagen and other proteins as it ages, making the skin appear dull, saggy, discolored, and wrinkly. Many of these changes are due to the sun, as it bombards the skin with harmful ultraviolet (UV) radiation. When the skin is exposed to the sun’s UV radiation, it produces reactive oxygen species and leads to oxidative stress. The result is of these oxygen radicals is thickened, damaged, photo-aged skin. Unfortunately, the cells that could help replenish and rejuvenate the skin—epidermal progenitor cells—may also be damaged by UV radiation. Indeed, as we age, we produce fewer and fewer of these helpful cells. Thus, the skin is left defenseless.
Researchers are looking for ways to fight back against the ravaging effects of age and sun damage on human skin. Some have reasoned that if the skin lacks epidermal progenitor cells during aging, why not try to protect or restore those cells? Consequently, some scientists have studied the effects of injecting stem cells directly into the skin (with promising results). However, many patients would like to have the same skin rejuvenation effect without painful injections. Scientists are learning that the beneficial effects of stem cells come mostly from the things that they secrete rather than the stem cells themselves. This means that doctors could potentially take the fluid that a stem cell secretes and use that liquid as a treatment, rather than injecting whole stem cells into a patient’s skin. Indeed, this is the approach that researchers recently pursued and published.
Researchers began their research by collecting epidermal progenitor cells taken from mesenchymal stem cells. These epidermal progenitor cells are the stem cells that give rise to skin. Epidermal progenitor cells also produce substances that help support natural, youthful skin growth and development. The researchers allowed these epidermal progenitor cells to produce and release substances into the surrounding solution. They then collected that solution and used it in subsequent experiments.
In the first set of experiments, researchers showed that the cell-free fluid derived from stem cells could protect skin cells from oxidative stress caused by hydrogen peroxide. Indeed, something (or things) released by the stem cells prevented skin cells from undergoing the types of changes they would endure during sun damage. In fact, the treatment apparently caused the skin to increase its own natural defenses by producing more antioxidant enzymes and increasing the creation of new collagen.
Encouraged by these results, the researchers then conducted a clinical study of 25 people between the ages of 29 and 69. They took the same cell-free fluid derived from stem cells and applied it topically to the skin of volunteers twice a day for four weeks. The treatment significantly reduced skin depressions and wrinkles. Treatment also noticeably improved the texture of the skin.
Given the apparent safety and efficacy of this cell-free treatment, researchers are likely to continue to test these treatments in larger clinical trials. The results are exciting because they offer the possibility of a topical stem cell treatment without directly injecting stem cells themselves. Indeed, patients may someday be able to use cell-free stem cell skin rejuvenation treatments at home.
Reference: Sohn, SJ. et al. (2018). Anti-aging Properties of Conditioned Media of Epidermal Progenitor Cells Derived from Mesenchymal Stem Cells. Dermatology and Therapy. 2018 Jun;8(2):229-244.
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