Skin tissue engineering.

The coverage of extensive wounds with viable autologous keratinocytes remains the only option of treatment if autologous donor skin is not obtainable. There is evidence that proliferating keratinocytes, as suspended cells or as a single layer, are adequate for wound closure. Understanding keratinocyte-matrix interactions not only allows us to influence keratinocyte outgrowth, adhesion, and migration, but may also guide us to modify matrix molecules for enhancing keratinocyte take. Further approaches may include the generation of genetically manipulated keratinocytes, which allow the use of an off-the-shelf epidermal replacement. As surgeons, our goal is to help burn patients with the best quality of skin in the shortest time possible. As tissue engineers, we have not achieved the goal of a universal skin product. By continually reviewing the options and using them, we can at least use the proper material in the adequate situation. Because of the limited resources, the need for comparisons of clinical effectiveness and cost are ever more important. As anatomy and physiology of engineered skin substitutes improve, they will become more similar to native skin autografts. Improvement of skin substitutes will result from inclusion of additional cell types (eg, melanocytes) and from modifications of culture media and scaffolds. Skin-substitute materials may be able to stimulate regeneration rather than repair, and tissue-engineered skin may match the quality of split-skin autografts, our present gold standard.

[Skin tissue engineering]. / Gewebeersatz (tissue engineering) von Dermis und Epidermis.

Cultivated epithelial autografts as multilayered, thin sheets represent a common standard in clinically applied tissue engineering substitutes, outnumbering all experimental alternatives. However, the unsatisfying short- and long-term results concerning mechanical stability and scarring require alternatives. The cultivation and transplantation of cultured autologous keratinocytes as a single cell suspension in a fibrin matrix, combined with allogenic skin grafting, has been investigated extensively in athymic nude mice. Wounds can be reliably reepithelialized after a cultivation period of only 14 days. Moreover, the successful combination of keratinocyte fibrin suspension and acellular dermis in an attempt to regenerate full thickness skin defects in a pig model has been demonstrated. The usefulness of subconfluently cultured keratinocytes-which can be harvested very early and are easy to handle-is enhanced by cotransplantation with decellularized dermis.