MATTEK’S TISSUE MODELS: NEW DEVELOPMENTS.
- TR Number: 151
- Authors: Klausner, M. Mattek Corp., Ashland, MA 01721.
Mattek commercially offers three organotypic tissue models for irritancy and mechanistic studies: 1) EpiDerm™, a highly differentiated, keratinocyte-only model of the epidermis, 2) MelanoDerm™, a second generation version of EpiDerm in which functioning melanocytes have been incorporated, and 3) EpiOcular™, a three-dimensional, non-cornified epithelial tissue model which has been useful in predicting ocular irritancy in vitro. Previously, correlation of EpiOcular results yielded a useful “prediction model” which consisted of an equation from which one could calculate a Draize score based on in vitro MTT EpiOcular results. However, certain classes of materials (e.g. alcohol containing) were shown to be over-predicted by the assay. In addition, other assay protocols have been proposed which did not involve dilution of the test materials. Results comparing three different assay protocols run head-to-head will be presented along with an alternative correlation for alcohol-containing materials. Regarding EpiDerm, new immuno-histochemical results show that the oncogene, c-fos, and the tumor suppressor gene, p-53, are expressed following treatments known to induce carcinogenesis in animal studies. In addition, a new “long life” maintenance medium for EpiDerm has been developed which maintains normal epidermal structure for up to 2 weeks following shipment. A recent addition to the EpiDerm line of tissues, EPI-201*, will be introduced. EPI-201 is a three-day-less-mature version of EpiDerm. Results with EPI-201 show that it can be cultured after storage and shipping to yield tissue which is histologically and functionally identical to standard EpiDerm. As such, it is believed that EPI-201 will prove to be a valuable tool to study modulators of epidermal differentiation.