For the first time, a team of U.S. scientists has developed a technique to convert human stem cells into a type of cell that is capable of initiating hair growth. When these cells were transplanted into mice lacking hair, they successfully induced human hair growth, suggesting that with further development, this method could lead to a cell-based treatment for people suffering hair loss.
“The method is a marked improvement over current methods that rely on transplanting existing hair follicles from one part of the head to another,” lead scientist Alexey Terskikh said in a news release. “Our stem cell method provides an unlimited source of cells from the patient for transplantation and isn’t limited by the availability of existing hair follicles.”
Hair loss, or alopecia, affects a significant number of people worldwide. It’s estimated that around 30 million women in the U.S. suffer from hereditary hair loss, and as many as 50 million men. Alopecia can be caused by a variety of factors from genetics to the environment, such as skin conditions or certain drugs. Not all hair loss is permanent and for some people it’s reversible, for example when caused by chemotherapy or nutritional deficiencies. While it’s possible to slow down the progression of hereditary hair loss with treatment, unfortunately there is no cure for this condition.
Realizing the need for better treatments to help people with permanent hair loss, scientists from Sanford-Burnham began contemplating the potential of using stem cells. Embryonic stem cells, which are derived from very early mammalian embryos, are undifferentiated “blank slate” cells, meaning they have not yet assumed a particular role or function. Scientists are particularly interested in these cells because they have the ability to become any cell in the human body, promising an almost unlimited supply of a particular cell type.
For the study, which has been published in Plos One, scientists started off by turning these human embryonic stem cells into neural crest cells, which are a type of cell that appear early on in development and that turn into cells of the nervous system, pigment-containing cells and components of the skeletal system, among other things. Then, they converted these cells into dermal papillae cells, which are known to regulate hair follicle formation and growth cycle.
These cells were then transplanted under the skin of immunodeficient “nude” mice, which as the name suggests lack body hair. These mice are useful in scientific research because they can receive grafts and transplants without rejecting the tissue. The researchers found that the cells were able to induce hair follicle formation in the mice, and were much more useful than transplanted dermal papillae which were isolated straight from human scalps. That’s because these cells can’t be obtained in sufficient quantities and quickly lose their ability to induce hair follicle formation when grown in dishes.
“Our next step is to transplant human dermal papilla cells derived from human pluripotent stem cells back into human subjects,” said Terskikh. “We are currently seeking partnerships to implement this final step.”