In this project we address another difficulty in the clinical application of fetal skin grafts for prenatal closure of spina bifida lesions: relatively fragile dermo-epidermal skin substitutes have to sustain a particular mechanical stress especially in case of fetoscopic surgery where the substitute has to be furled and pushed trough the fetoscope. One of the reason of fragility of skin substitutes consists in the absence of rete ridges which forms the typical wave-shaped structure of the natural dermo-epidermal junction. Rete ridges increase the surface area of the epidermal-dermal interface, thus providing structural integrity and mechanical strength. They also increase the capillary-epidermal surface area to improve the nutrient supply to the avascular epidermis. Using very small fetal tissue left-over biopsies we want to obtain fetal fibroblasts, endothelial cells and keratinocytes for the assembly of dermo-epidermal fetal skin substitutes. We want to recreate rete ridges by means of pistons which impress the wave-shaped structure on the collagen matrix during plastic compression of the dermal component. The bioengineered skin substitutes will be raised in vitro or in vivo on nude rats. They will be analysed by histological, whole-mount stainings and confocal microscopy. The vascularization pattern will be studied and the shear-stress resistance will be measured.
