Research team led by Yann Barrandon at the EPFL (Ecole Polytechnique Federale de Lausanne) and the CHUV (Lausanne University Hospital) has discovered, using animal model, that certain cells (clonogenic keratinocytes) inside hair follicles are true multipotent stem cells, capable of developing into the many different cell types needed for hair growth and follicle replacement.

They demonstrate that these holoclones can be used for long-term follicle renewal.

Previously Barrandon (in 2001) was part of a French research team who reported in the Cell Journal that stem cells could be used to generate skin containing hair and sebaceous glands in mice. At that time it was unclear whether the stem cells in hair follicles were true stem cells, capable of long-term renewal, or multipotent progenitor cells that would not permanently engraft in the follicle.

In the current PNAS study, the Swiss researchers have answered that question, using rat whisker hair follicles to demonstrate that the clonogenic keratinocytes in hair follicles are true stem cells.

“With the progeny of a single stem cell, it would be theoretically possible to generate the complete hair bulb of a human being, and one that would last for years,” explains Barrandon.

The ability of the stem cells in hair follicles to repeatedly regenerate all the different cell types of the follicle and sebaceous glands has important implications for regenerative medicine. The method could one day be used to regenerate hair on patients with severe burns. This study is a logical complement to other work in Barrandon’s Laboratory of Stem Cell Dynamics, recognized for research into the reconstruction of injured tissues and organs.

Source: October 3rd Advance online edition of the Proceedings of the National Academy of Sciences