Vascularization of human acellular dermis on chick chorioallantoic membrane

The EU has adopted a ban on animal testing for cosmetic ingredients or finished products. These regulations have promoted the research on alternative reliable systems, some of which have already been approved. In order to develop models of engineered skin, a vascularised de-epidermised dermis (DED) was developed on chicken embryo chorioallantoic membrane (CAM) as alive support. DED was obtained using skin fragments from discarded surgical skin treated by repeated freezethawing cycles in liquid nitrogen and irradiated by 3.5 Gy from a cobalt source. Fertilized eggs were incubated in a vertical position and windowed 3 days after incubation for alive embryo selection. At day 6, DED was deposited on the CAM with the basal lamina contiguous to the latter. DED was added, alternatively, with foetal calf serum, epidermal growth factor, and keratinocyte culture medium. An untreated group was used as control. Embryos were photographed every day and scarified at day 12. DED together with the CAM were fixed and processed for histological examination. Stereoscopic examination during the experiments showed an easily invasion of the implanted DED by chicken erythrocytes. Due to the DED thickness, methaemoglobin was sometimes observed. At day 12, the non supplemented DED shrunk with an evident size reduction. Histological examination showed the colonization of the de-cellularised matrix and the formation of a rudimental vascular structure. These preliminary results look very promising for the production of vascularised systems, a basis for the engineered skin construction.