Background: Preferred coverings for excised burn wounds when sufficient autograft skin is not available are fresh or cryopreserved cadaveric skin. Problems with supply, preservation, immune rejection, and potential infection transmission accompanying the use of allograft skin underscore the need for effective alternative temporary skin replacements.
Methods: We cultured human neonatal fibroblasts (HF) for 4 to 6 weeks in nylon mesh of Biobrane, a synthetic dressing consisting of a thin layer of silicone bonded to nylon mesh. Secreted matrix proteins were identified by immunostaining and quantitated, and growth factor-specific messenger RNAs were identified by reverse transcription-polymerase chain reaction. Living grafts (Biobrane/HF) were sutured to full-thickness, excised wounds on athymic mice; control animals received Biobrane alone. Wounds were observed and biopsy specimens were obtained at intervals during the subsequent 40 days.
Results: After 3 to 6 weeks of culture in Biobrane the HF proliferated and secreted matrix proteins including type I collagen, fibronectin, and decorin, as well as messenger RNA for several growth factors (acidic fibroblast growth factor, basic fibroblast growth factor, and keratinocyte growth factor). Biobrane/HF grafts were transferred to full-thickness wounds, resulting in rapid fibrovascular ingrowth from the wound and effective wound closure for up to 40 days with minimal inflammatory responses. Biobrane control grafts adhered initially to wounds, but within several days many grafts developed subgraft exudates; histologic sections revealed marked inflammatory responses in these wounds. By 20 days, most BB grafts were separating from the underlying wounds that were closing by epithelialization and contraction.
Conclusions: The Biobrane/HF living skin replacement provides long-term biologic coverage of full-thickness wound defects in mice with rapid incorporation of a living tissue matrix into the wound bed. Because HF have been found to be relatively nonantigenic when transferred to allogeneic hosts, Biobrane/HF grafts could replace the use of cadaveric allograft skin for achieving temporary wound closure after burn wound excision. Biobrane/HF grafts may persist on human wounds for weeks or months, with long-term persistence perhaps primarily dependent on durability of the silicone rubber layer.