According to the American Hair Loss Association, two-thirds of men will experience hair loss by the age of 35. But women are also affected, making up 40% of all hair loss sufferers. Affecting self-image and emotional well-being, the condition has been a difficult one to treat. But a 2014 study brings hope - in the form of human hair-follicle-generating stem cells.
Researchers from the Perelman School of Medicine at the University of Pennsylvania published results of their study in Nature in January 2014, where they describe the method by which they were able to convert adult cells into epithelial stem cells (EpSCs).Although using stem cells to regrow hair follicles has been a potential technique for combatting baldness, until now, nobody has been able to produce enough of these cells. The team says they are the first to achieve this result in either humans or mice. Led by Dr. Xiaowei "George" Xu, associate professor of pathology and laboratory medicine and dermatology at the University of Pennsylvania, the scientists started their research by using human skin cells called dermal fibroblasts.
The researchers converted the human skin cells into induced pluripotent stem cells (iPSCs) by adding three genes. These iPSCs are able to change into any cell types in the body, so the researchers converted them into epithelial stem cells, which are normally found in a part of hair follicles.
The arrows show hair shafts, which were formed by iPSC-derived epithelial stem cells.Using techniques from other research teams to convert iPSCs into keratinocytes - a main cell type in the top layer of the skin - Dr. Xu and colleagues showed they could "force" the iPSCs to make large quantities of EpSCs by controlling the timing of growth factors the cells received.When they implanted these EpSCs into mice, the cells regenerated cell types of human skin and hair follicles, and also created recognizable hair shafts, which the team says shows promise for eventually regrowing hair in humans. In 18 days, 25% of the iPSCs converted into EpSCs, which were then purified using the proteins expressed on their surfaces, the team notes.
After mixing the human-derived EpSCs with dermal cells from mice, the team grafted them onto the skin of the mice and produced a functional human epidermis - the outermost layers of the skin. The hair follicles that were produced from this, notes the team, were structurally similar to human hair follicles.Dr. Xu says that this is the first time anyone has made scalable amounts of epithelial stem cells that are capable of generating the epithelial component of hair follicles,adding that the cells could aid in wound healing, cosmetics and hair regeneration. However, these cells are not yet ready for use in humans because the team has only solved one part of the equation. A hair follicle contains both epithelial cells and a certain kind of adult stem cell called dermal papillae.
We all lose hair - around 50-100 hairs each day, on average. But for some people, hair loss can be much more severe, causing partial or complete baldness. The most common form of hair loss, also referred to as alopecia, is hereditary hair loss, in which a person inherits the condition from their mother or father. This affects more than 50 million men and 30 million women in the US. Other causes of hair loss include extreme stress, medical conditions - such as thyroid disorders, anemia and psoriasis - and use of certain medications. Current treatments for hair loss include hair restoration medication, though the results vary in each patient. Another treatment is hair transplantation, which involves removing hair follicles from one area of the head with normal hair growth and placing them in an area that lacks growth.
In this latest study, Alexey Terskikh, PhD, associate professor in the Development, Aging and Regeneration Program at Sanford-Burnham, and colleagues reveal how they effectively grew new hair using human pluripotent stem cells (hPSCs) - cells derived from human embryos or human fetal tissue that can become any other cell type in the body. They say the technique - detailed in the journal PLOS ONE - has the potential to be more effective than current hair transplant methods. Dermal papilla cells derived from hPSCs induced hair growth in mice. Terskikh and colleagues created a technique that encouraged hPSCs to turn into dermal papilla cells, which are responsible for regulating the formation of hair follicles and the hair growth cycle.
On transplanting these dermal papilla cells into mice, the team found they successfully induced new hair growth. The researchers note that because adult dermal papilla cells cannot be gathered in large quantities and quickly lose their ability to trigger hair follicle formation in culture, they are unsuitable for hair transplants. But these findings suggest a technique that may get around this problem. Terskikh says:
We have developed a method using human pluripotent stem cells to create new cells capable of initiating human hair growth. The method is a marked improvement over current methods that rely on transplanting existing hair follicles from one part of the head to another. Our stem cell method provides an unlimited source of cells from the patient for transplantation and isnt limited by the availability of existing hair follicles.
The researchers say they now plan to transplant the hPSC-derived dermal papilla cells back into humans to test their effectiveness. We are currently seeking partnerships to implement this final step adds Terskikh. There are some major advancements happening in treatment for hair loss. In August 2014, Medical News Today reported on a study claiming a bone marrow disease drug restored hair loss in patients with alopecia areata - a disease in which the immune system attacks the hair follicles. In another study, researchers from the University of Pennsylvania revealed how they created hair-follicle-generating stem cells, which show potential for regrowing hair in humans.