Do stem cells hold the key to younger-looking skin?

STEM CELLS, though controversial, often play a key role in drug research. Now these materials are finding new applications in skin care, and stem cells are the latest buzzword in the anti-aging category. Yet scientific opinion remains divided on their origin. One opinion is that stem cells arise when sperm fertilizes an egg, while the other is that they originate in the inner cell mass of the blastocyst. Stem cells have the ability to go through numerous cycles and cell divisions while maintaining their undifferentiated state. They also have the capacity to differentiate into other cell types such as muscle, blood and nerve tissue.

Adult stem cells reorganize, heal and repopulate the skin with new cells. They arise from the basal layer of the epidermis and at the hair follicle base. Adult stem cells, as opposed to embryonic stem cells, repair and regenerate damaged tissues. Theoretically they possess the ability to create new skin cells and regenerate the skin for a lifetime, but age and environmental factors cause them to function less efficiently, resulting in older-looking, aged skin. Stem cell-based creams reportedly stave-off this process by either stimulating or protecting stem cells deep in the basal layer of the epidermis.

Stem cells divide relatively infrequently. With age, stem cells lose their proliferative capacity and perhaps their ability to respond to signals to produce more epithelial cells, according to R. Ghadially, a dermatologist and skin stem cell specialist at the University of California at San Franciscco's Institute for Regenerative Medicine. Increasing proliferation is the ultimate complexion rejuvenator.

Stem Cells in Skin

Epithelial skin stem cells are found in the basal layer of the epidermis, while hair bulge stem cells are found in hair follicles. Furthermore, hair follicular stem cells, tooth stem cells and skin stem cells all show therapeutic promise and may one day restore hair to bald men, teeth to those in need and skin to scarred patients, according to Dr. Denis English, editor of Journal of Stem Cells and director of cell biology at the University of South Florida.

Changes in the skin are caused by aging, disease or injuries. Although drugs can relieve consequences of the disease, they will not suppress the cause. Therefore, the most attractive strategy is to replace disabled cells, and to this end, to take advantage of stem cells. (1) According to Gregory Brown, creator of ReVive, accessibility also makes skin stem cells appealing to cosmetic chemists. Stem cells are readily available in hair follicles and sweat glands. The ratio of stem cells to regular cells in skin is still hotly debated. It was once thought to be 1 in 10, but is now suspected to be more like 1 in 10,000.

Stem Cells and Aging

Stem cells have a limited life expectancy because UV, smoking and ozone all hasten skin cell depletion, resulting in DNA damage, telomere shortening and oxidative stress. Cell depletion does not activate stem cells to change into new cells. Aging stem cells lead to a decreased capacity for repair, an increased incidence of degenerative diseases and an increased incidence of cancer in tissues that contain stem cells. Skin rejuvenation comes to a halt when stem cells remain inactive. Under the right stimulus, stem cell activity could be jump-started to initiate skin rejuvenation.

Stem cells have unique secondary structures of DNA and RNA. Stem cells have special components in the cytosol-epigenetic factors. Stem cells are sensitive to environmental stress factors and hence protection and maintenance of stem cells is of great importance. Epigenetic profiles regulate the gene expression in stem cells, which enable cells to stabilize and maintain different characteristics despite containing the same genomic material. This is achieved by chromatin remodeling by DNA methylation (gene silencing), post-translational modification of histone proteins (e.g., acetylation for transcriptional competence) or mRNA inactivation through micro RNAs or small interfering RNA (siRNA).

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High-Priced Products

Marketers are presenting stem cell creams as the future of skin care. This article will review major stem cell-based anti-aging consumer products and the science surrounding stem cell technology.

Amatokin is available from Voss Laboratories in collaboration with Beilis Development Company. It has a hefty price tag of 190 euros or $258 per 30ml. Less expensive is Chris tian Dior's Capture R 60/80 XP cream, which still costs more than $100 for 30ml. StimulCell from N.V. Perricone retails for $155 for 1.7 fl.oz. Another product based on cellular tune-up action that is similar to stem cell is Estee Lauder's Re-Nutriv, which costs approximately $130. But the costliest product is ReVive's Peau Magnifique Youth Recruit. It comes in a lucite cube that houses four small silver tubes. A one-month supply of this super serum costs $1,500 ... can you believe it? The company insists that the high cost is because of a telomerase which is a bio-engineered enzyme costing about $4 million per gram.

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Actives and Claims

Although all of these products make similar claims, their backgrounds are quite different. For example, Amatokin got its start in 1988 when Russian scientist Taras Nikolaev from the Biotechnical Institute in Moscow and St. Petersburg studied peptide research to accelerate wound healing and skin repair. His team created a polypeptide with the ability to stimulate dormant stem cells in the skin, rejuvenate the skin and speed healing--truly a bold, astonishing claim. Amatokin is the first topical polypeptide that lights up stem cell markers (the means by which cell activity is measured). The polypeptide acts as a catalyst when it comes into contact with the upper keratinocyte cells of the epidermis, initiating a molecular signaling cascade that produces the increase in activity which was measured by the stem cell markers. (2)

In the case of StimulCell, young, undamaged cells were created by applying chemically reproducible oxidative stress to stem cells, which forces them to pump out 145 different proteins, carbohydrates and lipids. These materials are protect cells and relay regenerating messages, according to Dr. Perricone.

For Dior Capture R 60/80 XP creme, the active is a vitamin E derivative called alpha-tocopheryl phosphate, which creates a protective shield. ReVive Peau Magnifique Youth Recruit has an enzyme active called telomerase, which was first discovered in 1984, according to Bays Brown, the brand's founder. Finally, Re-Nutriv contains a stabilized version of reservatrol, an antioxidant produced by some plants to ward-off fungi and bacteria.

Amatokin initiates the release of very powerful growth factors responsible for cell proliferation, according to Louie Rinaldi of Voss Laboratories.

According to R. Ghadially a dermatologist and skin stem cell specialist at the University of California at San Francisco's Institute for Regeneration Medicine, this product increased the expression of certain stem cell markers. We only know what those markers indicate in embryonic cells. It has not been proven that they have the same correlation in adult cells. It is very promising, but more work needs to be done. His lab is conducting independent research on whether the markers in question do in fact indicate the presence of adult stem cells. (3)

How it Works

Amatokin highlights the expression of stem cell markers in the skin to reduce the appearance of serious wrinkles. It focuses on using polypeptides and enzymes to "awaken" the body's own reservoir of stem cells. We only know what those markers indicate in embryonic cells. There is no proof that the same holds true in adult cells. While very promising, more work needs to be done.

StimulCell contains cell-protecting and regenerating messengers. When the product is applied topically, these messengers reportedly attach to skin cells, signaling them to begin the reparative process. In one study, Dr. Perricone's product reduced acne, skin damage and wrinkles using the cell's own messengers. A cell is carefully guided toward rejuvenation.

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In an in-vitro study by Dior, the alpha-tocopheryl phosphate in Capture R60/80 XP reduced the number of stem cells lost in the epidermis after sun exposure. The company recruited 30 women scheduled for facelifts and asked them to use the cream on one cheek for two months before surgery. The treated skin showed 19% more epidermal cells. Rather than purporting to stimulate stem cells, this product makes rather modest claims that it protects and prolongs the functioning of the stem cells. The company asserts that the product's effectiveness is due to Stemsome, a sophisticated delivery system that transports ingredients into the skin. The system envelops each active ingredient in multi-stacked layers, which progressively melt as they are absorbed by the skin, releasing the active ingredient. According to Edouard Mauvais-Jarvis, director of scientific communications, each time a layer melts, the next one opens, enabling the ingredients to reach their target deep within the skin. This technology doesn't enhance the cells in any way, it merely creates a more beneficial environment to allow the stem cells to play their optimum role in regulating the skin.