Wolf, B.A., S.C. Kwan, J.A. Moral, and L. Rheins. Development of In Vitro Methods for Evaluating the Epidermal and Dermal Effects of Alpha Hydroxy and Amides. J. Invest. Dermatol. 1995. 104(4): 639. Abstract #511. [Reprinted by permission of Blackwell Science, Inc.]

Several in vitro methods chosen for their ability to replicate in vivo effects of selected alpha hydroxy acids and amides on the epidermis and dermis have been investigated. Cytotoxicity, prostaglandin release, morphology and histology on single cells and on tissue models were studied. Cytotoxicity, PGE-2 release in a commercial full skin model (ZK1300) correlated better with in vivo cumulative irritation data than cytotoxicity of fibroblasts. The amide derivative methoxypropylgluconamide (MPD) was not significantly toxic in fibroblasts or in the full skin model. Commercial cultures of differentiated keratinocytes (EpiDermÔ ) exhibited increased cell proliferation, increased cell viability and regular morphology of stratum corneum. These observations reproduce the in vivo results of epidermal biopsies after repeated topical applications. Histological staining for glycosaminoglycans (GAG's) indicated an increase in GAG content in the keratinocyte model but not as much as observed in vivo. In vitro models of the epidermis and dermis investigated in this study show promise for the screening of the epidermal effect of cosmetic ingredients but further refinements are necessary.