Study shows hair stem cells might repair nerve damage

Study shows hair stem cells might repair nerve damage

US and Japanese scientists reported Monday that tissues differentiated from human hair follicle stem cells have helped mice with severe sciatic nerve damage to walk again.

These results suggest that hair follicle stem cells can promote nervous axon growth and functional recovery after nerve injury, thus creating a potential opportunity for the clinical treatment of peripheral nerve diseases.

Embryonic stem cells, which are known to be capable of differentiating into almost all tissue cells, are at the center of ethical debates in many countries. Another problem linked to embryonic stem cells is immunologic incompatibility.

Because of these problems, many recent studies have focused on using adult stem cells for future clinical applications. Hair follicles afford a promising source of relatively abundant, accessible, active, pluripotent adult stem cells.

The research team, made up of researchers from the Massachusetts Institute of Technology, the Kitasato University of Japan and the University of California at San Diego, reported these recent study results in the latest issue of the journal Proceedings of the National Academy of Sciences.

In earlier studies, the team (led by Robert Hoffman of the University of California at San Diego) induced hair follicle stem cells to differentiate into blood vessel cells and neurons. These studies indicated the potential of hair follicle stem cells to form diverse cell types.

Now the team has successfully coaxed the hair follicle stem cells to evolve into the Schwann cells, a variety of glia cells that wrap around axons in the peripheral nervous system. When injected into mice with injured sciatic nerves, the Schwann cells produced myelin sheaths to surround the nerve axons, after which event the mice were able to walk normally.

“Therefore, by differentiating into Schwann cells, the hair follicle stem cells might stimulate the host axons to extend and, thus, to fill the transection gap,” reported the researchers. Cell-replacement therapies show lot of promise in the nervous system, where transplanted embryonic or bone-marrow stem cells have been demonstrated to promote functional recovery in animal models of spinal cord of peripheral nerve injury.

The paper does note that though the therapeutic potential of stem cell transplants is clear, many problems still exist. The use of fetal tissue raises ethical issues. And “the use of heterologous human tissue requires immunosuppression, which is particularly problematic in individuals with long-term, neuron-specific problems.”

Because hair follicle stem cells are generated from an autologous and accessible adult tissue source – namely, the skin – and because they can readily generate neuron-specific cell types, they may provide a solution to these problems.

Who knows, in the future, patients with injuries of the nervous system could be cured with their own hair follicles.