Biomaterials

Nerves of Hair

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Science  23 Nov 2007:
Vol. 318, Issue 5854, pp. 1219
DOI: 10.1126/science.318.5854.1219a

Hair growth is a complex process involving more than 30 growth factors, cytokines, and signaling molecules. Both the alpha and gamma keratins, which respectively form the structure and cross-linking in the hair fibers, can be extracted from human hair. Sierpinski et al. explored the use of keratin-based hydrogels, which form on mixing extracts with water, for the rapid regeneration of peripheral nerves. At present, small nerve defects can be repaired using fillers to provide a structural support, but only short gaps are amenable to this approach. In vitro testing showed that the keratin hydrogels improved Schwann cell proliferation and migration and showed either no effect or some up-regulation in the production of certain key proteins. Using a nerve injury model in mice, the authors then proceeded to compare regeneration results from the keratin protocol with autografts (in which a different form of tissue is used to patch a defect site), as well as controls where no material was added to the defect site. The hair-based hydrogels outperformed the autografts in reducing electrical signal latency and showed a greater increase in overall nerve area, as well as comparable improvements in a number of other tests. The authors believe that the hydrogels provide a framework for the Schwann cells and also retain a number of the regulatory molecules needed for hair growth, which are also involved in nerve repair. — MSL

Biomaterials 29, 118 (2008).

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