Multipotent stem cells discovered in hair follicle

Using an animal model scientists at the Ecole Polytechnique Federale de Lausanne (EPFL) have demonstrated that these holoclones can be used for long-term follicle renewal.

The researchers isolated stem cells from rat whisker follicles, labeled them and grew them in culture for 140 generations. They then implanted progeny cells into the skin of newborn mice whose hair follicles were just being formed. This skin was then grafted onto athymic (nude) mice. Some cells were incorporated into developing follicles, but other follicles were completely made up of labeled cells.

Each progeny cell contributed to the formation of eight different types of cell in the follicle, including those of the outer root sheath, inner root sheath, the hair shaft, the sebaceous gland and the epidermis.

After 125 days, a biopsy was taken from the graft, and labeled stem cells were isolated, subcloned, cultivated and then once again transplanted. The rat whisker stem cells participated again in forming all the cell types needed to form the hair follicle and sebaceous glands, resulting in hair bulbs that underwent repeated normal phases of growth, rest and regeneration.

The fact that the transplanted cells participate in the hair cycle over long periods of time shows that they are true multipotent stem cells and not progeniture cells, leading the researchers to suggest that it could be possible to generate the complete human hair bulb capable of lasting for years. This finding has important implications for regenerative medicine. For example, the method could one day be used to regenerate hair on patients with severe burns.