Publish date: Mar 1, 2011
By: Louise Gagnon
Source: Dermatology Times
* Most aesthetic product lines tout enzymes or peptides that serve to protect or improve stem cell function
* Products containing telomerase have raised concerns that they may promote tumor growth and invasion of skin cancer cells
Metairie, La. — Stem cell products hold the promise of skin rejuvenation and skin repair, and the science that supports the claims of their benefits makes sense, but there are scant clinical studies in human subjects that demonstrate their efficacy and safety.
"We know that as you age, stem cells reduce in function and number," says Patricia Farris, M.D., a board-certified dermatologist and dermatologic surgeon in Metairie, La. "Stem cells are important in maintaining skin homeostasis and function and for repairing skin after injury."
It appears that stem cell dysfunction or loss of function is the result of several key factors including oxidative stress, ultraviolet light, inflammation and telomere attrition, Dr. Farris says.
"The logic is that if we can boost stem cell function, we can rejuvenate the skin, making it function more like it did when it was young. And this makes total sense as an anti-aging strategy," Dr. Farris says.
Stem cells' role
Stem cells are found in the epidermis, dermis, bulge region of the hair follicle and sebaceous glands.
"Stem cells help regenerate the epidermis, maintain epidermal barrier function, and also support the dermal matrix," Dr. Farris says. This, she says, is why in intrinsic aging, poor wound healing, skin dehydration, wrinkling and loss of elasticity are seen.
"Stem cells are important for keeping skin healthy and looking young," Dr. Farris says. "We know that as we get older, aging fibroblasts don't work as well. They produce excessive amounts of MMPs and less collagen."
Stem cell cosmeceuticals do not actually contain stem cells. Most product lines tout enzymes or peptides that serve to protect or improve stem cell function. Some of the first stem cell cosmeceuticals to market contained the enzyme telomerase. Telomerase protects telomeres from shortening, thus preserving stem cells.
Lack of evidence
Dr. Farris says the products that are available on a retail basis are costly, and she hesitates to recommend them to patients in the absence of good clinical studies.
"As stem cells get older, there is telomere attrition," she says. "It makes sense that if you repair the telomeres, you can restore the activity of the stem cells.
"We don't have proof in human skin yet that when these skincare products are applied to the skin that they can really boost stem cell activity, and, more importantly, make the skin look younger," Dr. Farris says. Most of the research on stem cell products has been done in vitro and needs to be translated to the clinical setting with human subjects, she adds.
There have been concerns regarding cosmeceuticals containing telomerase, in that it has been shown that telomerase may promote tumor growth and invasion of skin cancer cells.
"We have no evidence to suggest that any of these topical skincare products containing telomerase pose a danger to patients, but it remains a theoretical concern," Dr. Farris says. "We have to demand that good studies are performed to ensure patient safety."
Cosmeceutical advances
Natural or botanical telomerase-activating compounds are also finding their way into nutraceuticals and cosmeceuticals. Geron Corporation holds patents on the compound telomerase activation-65 (TA-65) found in the Chinese herb astragalus. Pivotal studies demonstrated that oral supplementation with this natural telomerase activator resulted in an improvement in skin condition in male patients age 60 to 85.
"Consumers always favor products that are natural, making this supplement an attractive option for some anti-aging enthusiasts," she says.
Yet Dr. Farris says she believes more studies are warranted. "We have a lot more to learn about TA-65 before we can give it a thumbs-up," she says.
Amatokin, marketed by Voss Laboratories, launched in 2007 and remains a popular stem cell cosmeceutical. According to manufacturers, the active ingredient in Amatokin is polypeptide 153, Dr. Farris says.
"It is a peptide that was discovered in burn patients," she says. Much of what is known about the natural repair process of the skin is found by observing what happens in the natural wound-healing process, she notes. How this peptide affects stem cells remains unclear, but manufacturers claim it activates dormant stem cells. Although Amatokin is sold widely, Dr. Farris says she has been unable to find clinical studies supporting its efficacy.
"At the end of the day, what our patients want to know is, 'Will this product make my skin look better?' Only with good clinical studies can we assure them that it's really worth the money," she says.
Mibelle Biochemistry takes a different approach to stem cell activation with its patented ingredient Swiss apple stem cell extract.
"We know that plants have stem cells," Dr. Farris says. "If you wound a plant, the callus tissue that forms is rich in plant stem cells."
Mibelle Biochemistry has patented a technology to culture and process a rare Swiss apple known for its long shelf life. This stem cell extract, called PhytoCellTec Malus Domestica, has been shown to slow cellular senescence in vitro.
"The extract can make old cells regenerate much like they did when they were young," she says.
Stem cell extract study
A small study of 20 patients age 37 to 64 demonstrated the impact of a Swiss apple stem cell extract on skin wrinkling. The test cream contained 2 percent Swiss apple stem cell extract, and subjects applied the cream twice daily to their crow's feet for 28 days. The test cream reduced wrinkle depth by 8 percent in two weeks and 15 percent in four weeks over baseline.
"It's important to note that this was a small user study with no control group," Dr. Farris says. "There are some products on the market that contain this ingredient."
Swiss apple stem cell extract has created a buzz since it was reported that first lady Michelle Obama is a fan of it, according to Dr. Farris.
"There is more to come on stem cells," she says. "It is an interesting area of research for skin biologists to look at to see if we can turn on stem cells in a positive way to rejuvenate skin."
