Stem Cells In Skincare
By Louise Hidinger, Ph.D.
In recent years, stem cells have attracted a huge amount of interest from the medical community for their potential to treat diseases and injuries that were considered untreatable before. Cosmetic companies have rushed to cash in on the buzz surrounding stem cells but do they live up to the hype? Let’s take a closer look!
What are Stem Cells?
Stem cells are undifferentiated cells found in multicellular organisms, that can either differentiate into specialized cells (e.g. in animals: bone, skin, nerve, and muscle cells) or they can divide to produce more stem cells. In stem cells, all genes are turned on, as compared to specialized cells, in which certain genes have been switched off. All stem cells are capable of going through a number of cell divisions while maintaining their undifferentiated state; stem cells may be categorized by their potency, or ability to differentiate into different cell types.
In mammals, there are two types of stem cells, embryonic stem cells, found within developing embryos, and adult stem cells, found in various tissues of mature (non-embryonic) organisms.
Recently, it has been reported in the journal Nature that mouse blood and skin cells can be converted to an embryonic stem cell-like state by exposure to an acidic environment; it is likely this procedure can also be carried out on other mammalian species including human.
Where do Stem Cells come from?
Stem cells are first generated in an embryo or seed from a fertilized egg, and then, as the organism grows and matures, these embryonic stem cells can either differentiate into specialized cells, or they become “adult stem cells”. In mammals, these adult stem cells are used as a repair system to replenish adult tissues. However, this reservoir of adult stem cells diminishes with age. In humans, stem cells may be obtained from bone marrow, blood and adipose (fat) tissue.
How is it applied to the skin?
At the moment, over-the-counter (OTC) beauty products touting stem cell technology only contain extracts of stem cells, and most contain plant stem cell extracts. It is not possible to maintain live stem cells in an OTC formulation. You can find beauty products with stem cell extracts in the form of moisturizing lotions, creams and serums that are meant to be applied once or twice daily.
Medical treatment with stem cells is another possibility, and this can involve live stem cells. One such treatment is the “stem cell face lift”, which involves concentrating stem cells from a patient’s body fat, and using the concentrate as a facial filler. This procedure is referred to as “autologous” or autotransplantation of tissue from one location in the body to another.
Some dermatologists use placental extracts from animals such as sheep, which are rich in embryonic stem cells from that animal, as facial treatment serums to aid recovery from cosmetic procedures.
How does it work?
Stem cells contain proteins that act as signaling molecules and growth factors, as well as high levels of antioxidants and other protective factors that allow these cells to replicate without losing their potential to differentiate. It is thought that extracts of these stem cells can stimulate skin to regenerate from within, by stimulating cellular division and increasing production of collagen, one of the main structural foundation molecules of skin.
Extracts of human stem cells are believed to be the most effective, since such extracts would contain growth factors that would act on human skin cells. One company, Lifeline Stem Cell Skincare, offers skin care products containing extracts of human stem cells, obtained from stem cell lines engineered from donated human eggs. Another company, Personal Cell Sciences, creates personalized skin care products with extracts of stem cells harvested from a customer’s own body fat.
Most OTC beauty products contain plant stem cell extracts, as these sources are much more readily available. These extracts contain antioxidants such as ferulic acid, ellagic acid and quercetin, all which help to inhibit oxidative damage to the skin.
In medical treatments, it is thought that stem cells harvested from a patient’s body and re-injected as facial filler, may help to restore declining reservoirs of adult stem cells naturally occurring in skin tissue, thus helping to stave off skin ageing. Meanwhile, non-human animal cells that are applied topically are meant to work in a similar manner as extracts of human stem cells, by supplying growth factors and nutrients that can help to stimulate skin healing and regeneration.
How good is the evidence?
Unfortunately, the jury is still out on beauty products containing stem cell extracts, as there is no firm evidence that these products, particularly those containing human stem cell extracts, can actually cause skin to regenerate or stimulate increased collagen production. Growth factors are typically proteins, large molecules which are very difficult to transport intact to their site of activity, which is the lowest layers of the epidermis where live skin cells are actively dividing, and to the dermis, where collagen is produced.
As for plant stem cell extracts in cosmetics, there is little evidence to show that these products are significantly better than comparable skin care products with ordinary plant extracts. Given that plant stem cell extracts contain high level of antioxidants, you may be better off using a product that contains pure antioxidants of a known concentration, rather than a product containing plant extracts with unknown and variable levels of antioxidants.
Medical treatments involving autologous transfer of live stem cells into a patient’s facial skin are still in the experimental stages. At the moment, there is still very little evidence that these stem cells are actually helping to rejuvenate skin by either replenishing the store of stem cells already found in skin, or by stimulating surrounding skin cells to divide and produce more collagen. However, there is definitely potential for successful treatment, as stem cells are known to produce high levels of growth factors, and direct injection of live cells into the skin means that these growth factors can reach those skin cells in the lower levels of the epidermis that are responsible for collagen production. Only time can tell whether stem cell-based medical treatments can live up to their promise, but it looks like exciting developments are ahead.
About the Author Louise Hidinger, Ph.D., is a Canadian cosmetic chemist.