Cars, hot water heaters, relationships: One second they're chugging right along, the next they break down. Inconvenient? Sure. Infuriating? No doubt. But small potatoes compared with skin, which goes kaput one excruciating day at a time, leaving small but unignorable traffic cones (wrinkles, spots, sad little sags) all along the way.
In what seems like a too-good-to-be-true twist, a factory that generates replacement parts—new, virgin cells—lurks right beneath our skin's own surface. What's more, some scientists and product formulators (and a bunch of very happy cosmetics marketers) believe we're closer than ever to tapping into it, thanks to a slightly scary-sounding new frontier: stem cells.
"Evolution, or God, or whatever you want to call it, created stem cells as an armamentarium in case of injury," says Gregory Bays Brown, MD, a Louisville, Kentucky–based former plastic surgeon whose skin-care brand, RéVive, was one of the first to launch a stem-cell-stimulating treatment last year. "They're a backup system. When things go wrong, they produce new cells."
Unlike any other type of cell, these "mothers" split into two different kinds of progeny: a new stem cell like itself and a daughter cell. Embryonic stem cells—the controversial kind—are prized for being profoundly versatile, able to differentiate into almost any kind of cell in the body, hence their potential to render patient-specific therapies for everything from heart disease to spinal cord injury. Primarily, though, these come from donated, unused embryos resulting from in vitro fertility treatments (though, in a major breakthrough, scientists from both the U.S. and Japan have recently been able to "reprogram" adult cells—including some taken from skin—to look and behave like embryonic stem cells).
The beauty industry, on the other hand, aims to jump-start the ready supply of adult stem cells in our own skin. Adult stem cells are a sort of semiassigned task force: undifferentiated cells that reside in, maintain, and repair specific tissues, such as bone marrow, liver, brain, muscle—and yes, skin. While they are limited to a single tissue type, adult stem cells are still amazingly versatile. Even without high-tech "reprogramming," their daughters are able to produce almost every kind of cell in that system. And they've already proven themselves rather useful: The stem cells in tiny cell cultures help biotech labs generate sheets of fresh skin grafts; for more than 30 years, the stem cells in bone marrow transplants have enabled patients to produce their own healthy new blood cells.
So, how many do we have? The ratio of stem cells to regular cells in skin is still hotly debated; it was once thought to be one in 10, but is now suspected to be more like one in 10,000. Tasked with repairing wounds and periodically regrowing hairs, these cells divide relatively infrequently, lying in wait until the body signals that it's showtime. "We believe that with age, stem cells lose their proliferative capacity and perhaps their ability to respond to signals to produce more epithelial [aka skin] cells," says Ruby Ghadially, MD, a dermatologist and skin stem cell specialist at the University of California at San Francisco's Institute for Regeneration Medicine. "If you could improve their ability to respond or to proliferate when required, that would be great."
Determining how, or whether, to do that has some corners of the skin-care industry at loggerheads. Some say increasing proliferation is the ultimate complexion rejuvenator; others argue that it could have disastrous consequences (more on that later). But one thing is certain: "Skin stem cells are very attractive," Ghadially says. They're plentiful—as the largest organ, skin is also one of the largest repositories of stem cells in the body—and easier to maintain and propagate in the lab than other stem cells. And they couldn't be more accessible. "Imagine if we could figure out how to reprogram them to act like, say, the insulin-secreting cells in the pancreas," Ghadially says. "You biopsy someone's backside, reprogram the stem cells, and use them to fix the problem. That's a great treatment."
Accessibility also makes skin stem cells extra-appealing to skin-care wizards. "Stem cells line hair follicles and sweat glands, so you don't have to worry as much about getting an ingredient into them as you do with other applications," Brown says. "They're right there."
Good thing for him: RéVive Peau Magnifique Youth Recruit comes in a hefty, impressive-looking Lucite cube that houses four small silver tubes—a one-month supply of a superserum that owes its whopping $1,500 price tag to a $4 million-per-gram ingredient, telomerase. In the body, this enzyme aides DNA replication, preventing chromosomal strands from losing bits of information when they split, thus warding off genetic mutations. Applied topically, Brown says, it can also send an SOS signal to stem cells, rallying them to respond as they would to an injury.
But some experts question whether the enzyme necessarily ignites stem-cell differentiation. "Telomerase plays a role in some, but probably not all, stem cells," says Amy Wagers, PhD, a principal faculty member of the Harvard Stem Cell Institute in Cambridge, Massachusetts. "I'm not familiar with any data suggesting it directs their differentiation or wakes them up."
How, then, to explain Peau Magnifique's before-and-after photos, which show a dramatic improvement in skin tone and texture, with fewer fine lines? "Lots of active ingredients work on skin cells to stimulate them to make by-products like collagen," says New York City dermatologist Dennis Gross, MD. "That's very different from stem-cell technology, in which the cells themselves form tissue."
While Brown seems to view stem cells' notoriety as an unfortunate downside ("It's so politically charged. People don't understand that some cells are controversial and some aren't," he says with a weary-sounding laugh), another brand is taking the shock factor to the bank. Produced by the same company as StriVectin, Voss Laboratories' Amatokin is named after its key ingredient, a polypeptide developed 18 years ago by Taras Nikolaev, PhD, a former biology professor who now presides over a large Russian biotech firm. The product's marketing scheme is original, to say the least; promotional materials allude to the ongoing stem-cell debate and describe a mysterious-sounding lab near Moscow surrounded by barbed wire and "machine-gun-toting armed guards."
At a recent press conference in Moscow (barbed wire, check; machine guns, nyet), the product's marketers called stem-cell technology "mankind's best and greatest hope." Nikolaev said he developed his 153-amino-acid chain in the hopes of aiding burn victims and healing surgical scars; its cosmetic potential first dawned on him when his wife demanded a wrinkle resolution.
"Amatokin's results are very exciting—the research shows an increase of expression of certain stem-cell markers," says Ghadially, who was asked by the company to review Nikolaev's studies independently in 2006. "But we only know what those markers indicate in embryonic cells. It's not proven that they have the same correlation in adult cells. It's very promising, but more work needs to be done." (Ghadially's lab has subsequently started independent research on whether the markers in question do, in fact, indicate the presence of adult stem cells.)
However, according to New York City–based dermatologist and skin-care baron Nicolas Perricone, MD, whether Amatokin—or anything else, for that matter—is simply able to activate stem cells may be beside the point. "You don't want a signal that just says `turn on' to stem cell activity. That's like a car that just has a gas pedal—it could be dangerous, resulting in overproduction, potentially even cancer," Perricone says. "You want cells that turn on, cells that moderate, cells that suppress activity, cells that steer." His latest creation, StimulCell, was made by submitting a sample of young, undamaged skin cells to chemically reproduced oxidative stress, inducing stem cells to pump out 145 different proteins, carbohydrates, and lipids that he calls "cell-protecting and regenerating messengers." Applied topically, these messengers are supposed to attach to skin cells, signaling them to begin the reparative process; initial in-house tests have shown a reduction in acne, skin damage, and wrinkles. "By using all the cells' own messengers, not just one go sign, we carefully guide the cell toward rejuvenation," Perricone says.
But specialists who don't have a product to sell wonder where revving up our stem cells will get us. "We think stem cells' low rate of division is actually a protection method," says Geraldine Guasch, PhD, a skin stem cell researcher at Rockefeller University in New York City. "The more cells divide, the greater their chance of DNA mutation." Cancer is basically the result of haywire cell production. Some scientists believe mutated stem cells may seed cancers that grow back even after chemo, which could make skin stem cells' inherent accessibility more of a bane than a benefit; susceptibility to UV damage could mean they're prey to even more mutations than internal cells. "In skin, it hasn't been demonstrated yet that a stem cell can be the start of cancer," Guasch says. "But if a company claims to increase stem-cell activity, I'd like to see proof that the chromosomes of these new cells don't accumulate mutations." (Besides, as Gross points out, anything that really proved it could alter cellular activity would constitute a drug claim and require FDA approval.)
That's why at least one brand aims to boost stem cells by protecting, not pushing, them. Dior's Capture R60/80 XP line employs alpha-tocopheryl phosphate (alpha TP), a souped-up form of the antioxidant vitamin E, which the company claims has been shown to fortify the protective microenvironment of these all-important "mother cells."
Dior's studies show that, in vitro, alpha TP reduced the number of stem cells lost in the epidermis after sun exposure. To demonstrate this in practice—not just in a petri dish—Dior scientists recruited 30 women scheduled for face-lifts (since biopsy scars would be invisible after surgery) and asked them to use the cream on one cheek for two months before surgery. The results were impressive: The treated skin showed 19 percent more epidermal cells and—proving an increase in stem cells in particular—a 48 percent leap in integrin beta-1, a protective molecule that only those cells produce.
Still, choosing a stem-cell cream over one with, say, time-proven retinols or hydroxy acids may be premature. "A lot of answers for science in general are hidden within the DNA of young cells, but it's a question of time and technique," says New York City dermatologist David Colbert, MD. "Stem-cell research is still really young. There's a lot more info to unravel." Thus, while formulators like Perricone charge deeper into uncharted waters (he's considering equipping his Madison Avenue flagship boutique with a machine he says would enable him to harvest and store clients' individual stem cells), other innovators are focusing on preserving the cells we already have.
To wit: Estée Lauder's latest iteration of the Re-Nutriv line (first introduced by Estée herself in 1958 at $110 a pop), Ultimate Youth Creme, contains a stabilized version of resveratrol, an antioxidant produced by some plants to ward off fungi and bacteria. It has been proven to extend the life of cells, act-ually slowing down turnover rather than speeding it up. Think of it as a cellular tune-up—possibly the best way to ward off a breakdown. So far, at least.