Hair grows from cells located at the base of the hair follicle. Hair follicles continuously cycle through growth, rest, and re-growth phases. In many people with hair loss, however, the follicles do not cycle correctly, with a growing number of abnormal follicles entering longer resting phases and producing only tiny invisible hairs.
Penn researchers suspected that stem cells located within the follicle bulge were responsible for hair growth. To test their theory, they used sophisticated cell labeling techniques to track the decedents of the stem cells during normal hair growth and isolate them in adult mice. They transplanted a slurry of these cells into the skin of a different set of adult mice with no immune systems. (The absence of an immune system prevented the mice from rejecting the stem cell transplant.)
Within four weeks, the transplanted cells made new hair follicles that produced new hair. "Now that we can isolate stem cells involved in hair growth, we can develop targets for manipulating hair growth," says study principal investigator George Cotsarelis, MD, Director of the Penn Hair and Scalp Clinic and Assistant Professor of Dermatology. Penn researchers hope to one day isolate stem cells in an adult scalp and transplant those cells to other areas of the scalp, generating new follicles and hair growth. Using the stem cell transplant as a treatment for hair loss, however, is at least 10 years away, says Cotsarelis.
The findings have implications not only for hair growth, but also for burn treatments. "The cells that we have isolated not only make hair follicles, but also can make other skin cells," says Cotsarelis. "These stem cells are there for your lifetime and have a huge capacity to proliferate and regenerate." Current skin grafting treatments fail to generate hair growth and often lead to unsightly scars. One day, doctors may be able to isolate and use stem cells in skin grafts for burn patients, generating better grafts with hairs.
Editor's Note:
You may also find this news release on-line at www.uphs.upenn.edu/news
The study, "Capturing and Profiling Adult Hair Follicle Stem Cells" is available online at http://dx.doi.org/ by entering the following digital object identifier 10.1038/Nbt950.
About PENN Medicine
PENN Medicine is a $2.2 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 (created in 1993 as the nation's first integrated academic 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.
Penn Health System consists of four hospitals (including its flagship Hospital of the University of Pennsylvania, consistently rated one of the nation's "Honor Roll" hospitals by U.S. News & World Report), a faculty practice plan, a primary-care provider network, three multispecialty satellite facilities, and home health care and hospice.
Journal
Nature Biotechnology