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LOP02: Topical Effects of Recombinant Growth Hormone on Burned Wounds

Introduction: The creation of complex three-dimensional (3D) tissue poses a great challenge in the field of tissue engineering (TE) since the functionality of a tissue is strongly dependent on its 3D structure. TE may be used for the treatment of burn injuries. Especially in case of large and deep burns, an adequate skin substitute is needed to avoid excessive scarring and infections. Our aim is the production of a skin equivalent which mimics physiological skin as closely as possible. Material and Methods: To realise our goal, we used laserassisted bioprinting (LaBP). It offers the possibility to position cells in a precise spatial 3D pattern. Skin equivalents were printed consisting of 20 layers of keratinocytes on top of 20 layers of fibroblasts. Resulting constructs were kept in vitro or implanted into full-thickness wounds in the dorsal skin fold chamber preparation in mice. Analyses were done histologically and by immunodetection. Results: After 10 days of in vitro culture, separate layers of keratinocytes and fibroblasts could still be seen. The keratinocytes formed a dense tissue including adherens and functional gap junctions. Also in vivo, after 11 days, the skin substitutes were still vital and tightly connected to the surrounding host tissue. A dense epidermal tissue was formed by the printed keratinocytes and the skin constructs were similar to normal mouse skin in histological analysis. A beginning vascularisation occurred. Moreover, hints for a beginning differentiation of the printed keratinocytes were found. Conclusion: In conclusion, LaBP of cultured skin cells is an adequate technique to create skin equivalents and offers great potential for the field of tissue engineering.