title: Skingineering I: engineering porcine dermo-epidermal skin analogues for autologous transplantation in a large animal model.
abstract: BACKGROUND
  Extended full thickness skin defects still represent a considerable therapeutic challenge as ideal strategies for definitive autologous coverage are still not available. Tissue engineering of whole skin represents an equally attractive and ambitious novel approach. We have recently shown that laboratory-grown human skin analogues with near normal skin anatomy can be successfully transplanted on immuno-incompetent rats. The goal of the present study was to engineer autologous porcine skin grafts for transplantation in a large animal model (pig study = intended preclinical study).
  
  
  METHODS
  Skin biopsies were taken from the pig's abdomen. Epidermal keratinocytes and dermal fibroblasts were isolated and then expanded on culture dishes. Subsequently, highly concentrated collagen hydrogels and collagen/fibrin hydrogels respectively, both containing dermal fibroblasts, were prepared. Fibroblast survival, proliferation, and morphology were monitored using fluorescent labelling and laser scanning confocal microscopy. Finally, keratinocytes were seeded onto this dermal construct and allowed to proliferate. The resulting in vitro generated porcine skin substitutes were analysed by H&E staining and immunofluorescence.
  
  
  RESULTS
  Dermal fibroblast proliferation and survival in pure collagen hydrogels was poor. Also, the cells were mainly round-shaped and they did not develop 3D-networks. In collagen/fibrin hydrogels, dermal fibroblast survival was significantly higher. The cells proliferated well, were spindle-shaped, and formed 3D-networks. When these latter dermal constructs were seeded with keratinocytes, a multilayered and partly stratified epidermis readily developed.
  
  
  CONCLUSIONS
  This study provides compelling evidence that pig cell-derived skin analogues with near normal skin anatomy can be engineered in vitro. These tissue-engineered skin substitutes are needed to develop a large animal model to establish standardized autologous transplantation procedures for those studies that must be conducted before "skingineering" can eventually be clinically applied.
authors.affiliation: Department of Surgery, Tissue Biology Research Unit, University Children's Hospital Zurich, Steinwiesstrasse 75, Zurich, Switzerland.
authors.forename: Erik
authors.initials: E
authors.lastname: Braziulis
authors.forename: Thomas
authors.initials: T
authors.lastname: Biedermann
authors.forename: Fabienne
authors.initials: F
authors.lastname: Hartmann-Fritsch
authors.forename: Clemens
authors.initials: C
authors.lastname: Schiestl
authors.forename: Luca
authors.initials: L
authors.lastname: Pontiggia
authors.forename: Sophie
authors.initials: S
authors.lastname: Böttcher-Haberzeth
authors.forename: Ernst
authors.initials: E
authors.lastname: Reichmann
authors.forename: Martin
authors.initials: M
authors.lastname: Meuli
mesh_terms: D000818:Animals; D049109:Cell Proliferation; D020405:Dermis / Q000166:cytology; D000078404:Epidermal Cells; D006085:Graft Survival; D015603:Keratinocytes; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D023421:Models, Animal; D016038:Skin Transplantation / Q000379:methods*; D013552:Swine; D023822:Tissue Engineering / Q000379:methods*; D014182:Transplantation, Autologous