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In mammals, organ induction occurs only during embryonic development except for hair follicles (HFs). However, HF-resident epithelial stem cells (HFSCs), which are responsible for repetitive HF regeneration, are not fully characterized. Here, we establish in vitro culture systems that are capable of controlling the ability of HFSCs to regenerate HFs. Based on a method that precisely controlled the number of HFs for regeneration, functional analysis revealed that CD34/CD49f/integrin β5 (Itgβ5)-triple-positive (CD34+/CD49f+/Itgβ5+) cells have multipotency and functional significance for continual hair regeneration. In native HFs, these cells reside in the uppermost area of the bulge region, which is surrounded by tenascin in mice and humans. This study unveils the subpopulation of HFSCs responsible for long-term hair cycling of HFs regenerated from bioengineered HF germ, suggesting the presence of functional heterogeneity among bulge HFSCs and the utility of our culture system to achieve HF regenerative therapy. [ABSTRACT FROM AUTHOR]

Abstract: Male‐pattern hair loss (MPHL, androgenetic alopecia) is a slowly progressive form of alopecia which begins after puberty. In 2010, we published the first Japanese edition of guidelines for the diagnosis and treatment of MPHL. It achieved the original goal of providing physicians and patients in Japan with evidence‐based information for choosing efficacious and safe therapy for MPHL. Subsequently, new therapeutic drugs and treatment methods have been developed, and women's perception of MPHL has undergone change and the term “female‐pattern hair loss (FPHL)” is becoming more common internationally. Thus, here we report a revised version of the 2010 guidelines aimed at both MPHL and FPHL. In these guidelines, finasteride 1 mg daily, dutasteride 0.5 mg daily and topical 5% minoxidil twice daily for MPHL, and topical 1% minoxidil twice daily for FPHL, are recommended as the first‐line treatments. Self‐hair transplantation, irradiation by light‐emitting diodes and low‐level lasers, and topical application of adenosine for MPHL are recommended, whereas prosthetic hair transplantation and oral administration of minoxidil should not be performed. Oral administration of finasteride or dutasteride are contraindicated for FPHL. In addition, we have evaluated the effectiveness of topical application of carpronium chloride, t‐flavanone, cytopurine, pentadecane and ketoconazole, and wearing a wig. Unapproved topical application of bimatoprost and latanoprost, and emerging hair regeneration treatments have also been addressed. We believe that the revised guidelines will improve further the diagnostic and treatment standards for MPHL add FPHL in Japan. [ABSTRACT FROM AUTHOR]

Finasteride is standard medical treatment for androgenetic alopecia; however, no large studies with 5 years or more of follow up have been performed in Japan. The authors followed Japanese men with androgenetic alopecia treated with finasteride for 5 years to evaluate long-term treatment efficacy. Of 903 men treated with finasteride (1 mg/day), 801 patients were evaluated over 5 years by modified global photographic assessment. Although the proportion of improvement was high (99.4%), modified global photographic assessment scores after 5 years of treatment were lower in patients with more advanced disease as measured by the modified Norwood-Hamilton scale. After separating patients into 'sufficient' and 'insufficient' efficacy groups according to the modified global photographic assessment score after 5 years (scores ≥6 and <6, respectively), multivariate analysis showed that independent risk factors of insufficient efficacy were age at start of treatment of 40 years or more ( P = 0.021) and classification on the modified Norwood-Hamilton scale ( P < 0.001), whereas presence of stress at start of treatment was a negative predictor ( P = 0.025). In conclusion, continuous finasteride treatment for 5 years improved androgenetic alopecia with sustained effect among Japanese. Younger age and less advanced disease at start of treatment were the key predictors of higher finasteride efficacy. [ABSTRACT FROM AUTHOR]