MELANODERM, AN EPIDERMAL TISSUE TO EVALUATE SKIN LIGHTENING AND DARKENING.

There is considerable interest in developing new cosmetic and skin care pharmaceutical formulations which modulate pigmentation of the skin. These products will be utilized to cosmetically alter one’s natural skin color (artificial tanning or skin lightening) or to combat skin pigmentation disorders such as melasma and post-inflammatory hyperpigmentation. In order to aid in the development of such products, we have produced MelanoDerm, a highly differentiated, three-dimensional tissue culture model of human epidermis that contains normal human melanocytes (NHM) and keratinocytes (NHK). Tissues have been cultured with NHM from Asian (A), Caucasian (C), and Black (B) donors. Over a three-week culture period, all tissues became increasingly pigmented and retained nor-mal epithelial morphology. As would be expected, the degree of macroscopic darkening in the tissues was dependent on the source of the melanocytes, i.e. B>A>C. Using cultures containing NHM-B, the ability of ascorbic acid (AA) to decrease skin pigmentation was investigated. Tissues cultured in medium containing 50 ug/ml AA or tissues treated topically with 50 ug/ml AA remained distinctly lighter than control cultures. A newly developed, quantitative melanin assay showed that melanin content for the treated tissues was 2.0 and 2.1 fold lower than controls for tissues seeded at NHK/NHM ratios of 10:1 and 30:1, respectively. On the other hand, the addition of known stimulators of melanogenesis such as β-fibroblast growth factor (β-FGF) and α-melanocyte stimulating hormone (α-MSH) caused cultures to darken faster than controls. These results indicate that this model will be useful to study melanogenesis, skin lightening, and other pigmentation phenomena of skin in vitro.

Alpha-MSH (Alpha-melanocyte stimulating hormone), Beta-FGF (b-FGF), Beta-fibroblast growth factor, MSH, MelanoDerm, Melanocyte stimulating hormone, Skin darkening, Skin evaluate, Skin lightening