The Etiology of Vitiligo: Autoimmune Theory and Neurohumoral Theory 4) Autologous cytotoxicity hypothesis. Environmentally exposed materials, such as phenols and quinones, and some of metabolites produced internally in the course of melanin synthesis are accumulated in the body, damaging melanocytes in people who are genetically sensitive to these materials. Chemical albinism is deemed to be caused by exposure to materials, which impairs the function of enzymes required for melanin synthesis. Tyrosine produces unstable byproducts during the synthesis of melanin, possibly damaging other cell matrices.5) Biochemical theory. This theory explains the development of vitiligo by melanocyte toxicity, which is caused by abnormality of the biopterin pathway.6) Oxidative stress hypothesis. Catalse is aberrantly lower in both lesions and nonlesional areas of vitiligo patients compared to normal people. This is related to high H₂O₂ concentration in the whole epidermal layer. 7) Melanocytorrhagy hypothesis. This hypothesis proposes that vitiligo lesions are caused by migration or loss of melanocytes, which are weakly attached to the surroundings, by a slight friction or other stresses.
Posted on: Sat, 15 Mar 2014 17:02:53 +0000
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