Limat A, Suormala T, Hunziker T, Waelti E R, Braathen L R, Baumgartner R
Dermatological Clinic, Inselspital, Bern, Switzerland.
Arch Dermatol Res. 1996;288(1):31-8. doi: 10.1007/BF02505040.
In humans and in animals, biotin deficiency causes pathological changes in the skin and its appendages. High doses of biotin may also have beneficial effects on skin, hair and fingernails in humans and animals with normal biotin status. Therefore, we investigated the effects of low and high concentrations of biotin on proliferation and differentiation of cultured outer root sheath cells from human hair follicles as an in vitro model for skin. The activities of biotin-dependent carboxylases were measured to evaluate the biotin status of the cells. In monolayer cultures of outer root sheath cells, proliferation and expression of the differentiation-specific keratins K1 and K10 were not influenced by extremely low concentrations of biotin (<2 x 10(-10) mol/l) or by pharmacological doses of biotin (10(-5) mol/l). Biotin deficiency of the cells was confirmed under the former condition by demonstrating decreased activities of the mitochondrial carboxylases. In organotypic cocultures of outer root sheath cells and dermal fibroblasts, in which stratified epithelia resembling epidermis were developed, the biotin concentration had no effect on the expression of all tested epidermal differentiation markers, including the suprabasal keratins K1 and K10, the hyperproliferation-associated keratin K16, involucrin and filaggrin.
在人类和动物中，生物素缺乏会导致皮肤及其附属器出现病理变化。高剂量的生物素对生物素状态正常的人类和动物的皮肤、毛发和指甲也可能有有益影响。因此，我们以人毛囊外根鞘细胞的体外培养作为皮肤模型，研究了低浓度和高浓度生物素对其增殖和分化的影响。通过测量生物素依赖性羧化酶的活性来评估细胞的生物素状态。在外根鞘细胞的单层培养中，极低浓度的生物素（<2×10⁻¹⁰mol/L）或药理剂量的生物素（10⁻⁵mol/L）对增殖以及分化特异性角蛋白K1和K10的表达均无影响。在前一种条件下，通过证明线粒体羧化酶活性降低来证实细胞存在生物素缺乏。在外根鞘细胞与真皮成纤维细胞的器官型共培养中，形成了类似表皮的分层上皮，生物素浓度对所有测试的表皮分化标志物的表达均无影响，这些标志物包括基底上层角蛋白K1和K10、与过度增殖相关的角蛋白K16、内披蛋白和丝聚蛋白。
