Androgenic Alopecia and Stress-Induced Premature Senescence by Cumulative Ultraviolet Light Exposure

Publisher： Karger

E-ISSN： 1424-4624|1|4|203-206

ISSN： 1424-4616

Source： Exogenous Dermatology, Vol.1, Iss.4, 2002-11, pp. : 203-206

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Abstract

Background: Ultraviolet light radiations (UVR) may be responsible for hair cycle synchronization and telogen effluvium in the animal and humans. The effect if any of cumulative UVR on chronic hair shedding and androgenic alopecia (AGA) is largely unknown. Objective: To compare the severity of AGA with the extent of solar elastosis. Method: The present study combining immunohistochemistry and computerized image analysis was undertaken in 140 men with AGA and 50 non-alopecic men. Solar elastosis was identified using the antibody to lysozyme, and collagen was revealed by Sirius red staining. The number and diameter of hair shafts were also assessed. Results: The scalp dermis was significantly thicker in AGA than in unaffected subjects. The difference was mainly due to a severer elastosis in baldness. The earliest signs of solar elastosis preceded hair thinning. When elastosis was thicker than 0.2 mm, a negative exponential correlation was found between hair diameter and severity of solar elastosis. Conclusion: Chronic UVR exposure of the scalp may affect the hair cycle and be one of the exogenous factors influencing negatively the progression of AGA. The induction of stress-induced premature senescence by reactive oxygen species and micro-inflammation might be operative at the level of the follicular stem cells.