Early Responders: Hair Follicle Stem Cells Contribute to Wound Healing, According to New Penn Study
Implications for Skin Problems Related to Diabetes and Other Disorders
(Philadelphia, PA) – Hair follicle stem cells are important contributors to the wound-healing process, according to new research by investigators at the University of Pennsylvania School of Medicine. Using an animal model, the researchers discovered that stem cells in the hair follicle are enlisted to help heal wounds in the skin. This finding, published online in Nature Medicine last week, may suggest a therapeutic target for the development of drugs to encourage and promote wound healing.
Wounds, including skin ulcers and other dermatological problems associated with diabetes, circulatory problems, and other diseases, are a growing medical problem in the United States, notes senior author George Cotsarelis, MD, Associate Professor of Dermatology. Previous work by the Penn research team had outlined the hair-growth process to show that stem cells in the hair follicle “bulge” area generate new lower hair follicles, which in turn, generate new hair. Their latest finding-that these same stem cells play a key role in initiating wound healing-will help lay the foundation for designing more effective wound-healing strategies.
Even minor wounding resulted in mobilization of follicle stem cells to generate daughter cells that quickly move into the wound area. “About one-third of the coverage of the wound came from the stem cells in the hair follicle,” says Cotsarelis. “In the future, we think that we will be able to design treatments that enhance the flow of cells from the hair follicle to the epidermis in the hope of enhancing wound healing and treating patients with wounds.”
Follow the Blue Light
Clinicians have known for some time that when the skin is abraded new cells come from the hair follicle. What remained a mystery was the exact nature of the origins of the new cells-specifically, what percentage stems from the deep follicle and what percentage from the epidermis near the wound.
Cotsarelis’ team found that adult stem cells from the lowest portion of the hair follicle, or “bulge,” quickly ascend the follicle in response to wounding and ultimately comprise about 30 percent of the new cells in a wound when it first starts to heal. In addition, the stem cells respond rapidly to surface wounding-within two days-by generating short-lived “transient-amplifying” cells that respond to acute wound-healing needs.
Using a genetically engineered mouse designed in their lab, the researchers were able to visually follow the fate of the stem cells as they migrated from deep within the skin to the surface wound site. The mouse stem cells express a reporter gene that encodes an enzyme, which can be detected with a special blue-color reaction. “We could see blue lines coming from the follicles going toward the center of the wound,” says Cotsarelis. “They formed a striking radial pattern like the spokes of a wheel.”
Hope for Hair Loss?
The research also showed that stem cells might be a therapeutic target in certain types of hair loss. Using a different engineered mouse also designed in the Cotsarelis lab, one in which the hair-follicle stem cells could be destroyed after administration of a drug, the researchers discovered that the animals permanently lost all of their hair. This hair loss mimics types of hair loss seen in humans called scarring alopecias. But, cautions Cotsarelis, more studies are needed to determine if the loss of hair-follicle stem cells plays a role in hair loss in humans.
This research was funded in part by the National Institutes of Health. Other co-authors in addition to Cotsarelis are Mayumi Ito, Yaping Liu, Zaixin Yang, Jennifer Nguyen, and Fan Liang, all from Penn, as well as Rebecca J. Morris from the Columbia University College of Physicians and Surgeons, New York.
PENN Medicine is a $2.7 billion enterprise dedicated to the related missions of medical education, biomedical research, and high-quality patient care. PENN Medicine consists of the University of Pennsylvania School of Medicine (founded in 1765 as the nation’s first medical school) and the University of Pennsylvania Health System.
Penn’s School of Medicine is ranked #2 in the nation for receipt of NIH research funds; and ranked #4 in the nation in U.S. News & World Report’s most recent ranking of top research-oriented medical schools. Supporting 1,400 fulltime faculty and 700 students, the School of Medicine is recognized worldwide for its superior education and training of the next generation of physician-scientists and leaders of academic medicine.
The University of Pennsylvania Health System comprises: its flagship hospital, the Hospital of the University of Pennsylvania, consistently rated one of the nation’s “Honor Roll” hospitals by U.S. News & World Report; Pennsylvania Hospital, the nation’s first hospital; Penn Presbyterian Medical Center; a faculty practice plan; a primary-care provider network; two multispecialty satellite facilities; and home health care and hospice.
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Wound at different stages of healing (A-C). The blue lines represent “clones” of cells originating from hair follicle stem cells. As the wound heals, the hair-follicle-derived cells migrate linearly toward the center of the wound in an apparent effort to heal the wound as quickly as possible. A, two days after wound. B, five days after wound; blue streaks indicate that clones move inward. C, eights days after wound, the epidermis has completely closed.
Photo Credit: George Cotsarelis, MD, University of Pennsylvania School of Medicine; Nature Medicine
I found this article when “goggling”
How clearly I remember the first time superfluous hair ruled, and ruined, my life. It was a sunny day, I was 13 and my parents had planned a day trip to the beach at Frinton.
I was thrown into a panic. I locked myself in the bathroom and applied Jolen Creme Bleach to my upper lip, and Immac to my legs, tummy and bikini line. The fumes were so toxic I’m surprised I didn’t pass out.
I waited the requisite 20 minutes or so, various brothers and sisters hammering on the bathroom door wondering what on earth I was doing, before I could at last wield my tiny wooden spatula and scrape all the gloop off, revealing the bald and so-much-better me beneath.
So began a battle that has continued, day in, day out, ever since.
To say that facial hair – on my upper lip, on my chin, sometimes extending down my neck, some of it white and fine, some of it black and coarse – currently rules my life would be an understatement.
On a long-haul, red-eye flight from New York the other week, my biggest preoccupation on landing was what on earth would have sprouted overnight, and how could I hide any new hairs until I got home, given my tweezers had been confiscated from my hand baggage? I write the word ‘pluck’ in my to-do list each morning. Some days, I despair at the extent of my problem.
In Los Angeles not long ago, in a sun-filled hotel room in front of one of those magnifying mirrors that light up, I literally reeled with shock: there were curling granny hairs so long they could be plaited. Stubby man-beard hairs. Someone should just place me in a circus and sell tickets.
Facial hair and its no less important cousin body hair has meant that I have always shied away from intimacy. I would avoid having sex in the morning in case my husband touched my face; I left my honeymoon halfway through for an emergency knee wax.
I have been known, when stranded miles from a beauty salon, to pluck the hairs from my legs one by one. I spent my 20s not having wild sex and binge drinking, but saving up for fortnightly appointments at the Tao clinic in Knightsbridge, where I would have electrolysis on my face, my cleavage, around my nipples (oh, dear God, the pain!) and on my tummy.
I invested in my own electrolysis machine and would sit at home for hours, shocking myself for longer than the recommended dose, just to be rid of those blessed little hairs that refused to give up the ghost.
have bought home-waxing kits, and discovered they never work. I have worn trousers, turned down dates, avoided parties and cancelled holidays – all because of the dictatorial demands of my body hair’s life cycle (if you go for a leg wax while the hair is too short, you are roundly told off by the therapist and sent packing).
Even as I sit here typing, there is one hand on my chin – feeling, searching, worrying.
And I am not alone. At the gym the other day, I saw countless women with razor bumps, ingrown hair, rashes, burns from waxes, regrowth: all of which are more unsightly, surely, than a bit of unadulterated fuzz.
The fashion for seeing hair removal as anti-feminist died out at the end of the 1970s so completely that even a hint of darkness beneath the arm of Julia Roberts can make headlines around the world.
But while the vast majority of women, at some time in their lives, will sprout unwanted hair on their face/breasts/stomach, the problem remains the last unmentionable taboo.
While even movie stars will admit to cellulite, the odd grey hair and wrinkles, not one will own up to whiskers.
We might now see, occasionally, a glossy magazine photograph of a woman with a roll of stomach fat, but I have never seen a picture of a female hairy chin.
I put this to the beauty editor of a monthly, and she recoiled in horror. ‘We can’t alienate readers,’ she said. ‘When we do a feature on waxing, we show a beautiful pair of sleek brown pins, not razor bumps or stubble. That would be revolting.’
But why is female hair seen as such a turn-off? While the sugaring and threading methods of removal have been around since ancient Egypt times, the fashion for women to be hairless took off only in the 1920s, when arms and legs began to be exposed for the first time.
Now, though, the tyranny to be completely bald has reached dizzying new heights.
The Brazilian wax, which leaves behind only a narrow ‘landing strip’ of hair, and which came about among young women in Brazil who wore thongs to the beach, has now infected every High Street beauty salon in the land.
Then there is its more extreme stablemate the Hollywood, which takes away everything, leaving the bearer distastefully childlike. My waxing specialist in London now does ‘seven or eight Hollywoods a day’ – a 70 per cent increase on this time last year.
Completely Bare, the American chain of spas dedicated to hair removal, has seen requests for a Hollywood quadruple in the past 12 months. Which must amount to something of a trend, but what fuels it? Is it men’s expectations from watching pornography where women are as bald as billiard balls or our own deep-seated neuroses?
‘Such insecurity has been instilled into women over generations; we have made not the least headway in the struggle to dispel it,’ writes Germaine Greer in her book The Whole Woman. ‘Women with “too much” (i.e., any) body hair are expected to struggle daily with depilatories of all kinds in order to appear hairless.