The inner root sheath （IRS） of human hair follicles consists of three concentric cell layers： the cuticle, Huxley's layer, and Henle's layer. All three layers are formed from the peripheral mass of matrix cells in the hair bulb. The formation of the IRS during the evolution of mammalian epidermis allowed the physiological exit of hairs produced inside the skin. Immunohistochemical staining indicates the human IRS cells express K6irs1, K6irs2, K6irs3, and K6irs4, the inner-root-sheath-specific type II epithelial keratins. In situ hybridization study found FGF-22 mRNA in the skin was preferentially expressed in the inner root sheath of the hair follicle. Therefore, FGF-22 is expected to be a unique FGF that plays a role in hair development.HHFIRSC from AcceGen Research Laboratories are isolated from human hair follicle inner root sheaths. HHFIRSC are cryopreserved at primary culture and delivered frozen. Each vial contains ＆gt;5×10^5 cells in 1 ml volume. HHFIRSC are characterized by their mesenchymal cell morphology and immunofluorescent method with antibody to fibronectin and CD105. HHFIRSC are negative for HIV-1, HBV, HCV, mycoplasma, bacteria, yeast and fungi. HHFIRSC are guaranteed to further expand for 15 population doublings at the condition provided by AcceGen Research Laboratories.
