DEVELOPMENT OF A TEMPORARY LIVING SKIN REPLACEMENT COMPOSED OF HUMAN NEONATAL FIBROBLASTS CULTURED IN BIOBRANE, A SYNTHETIC DRESSING MATERIAL

Background. Preferred coverings for excised burn wounds when sufficien t autograft skin is not available are fresh or cryopreserved cadaveric skin. Problems with supply, preservation, immune rejection, and poten tial infection transmission accompanying the use of allograft skin und erscore the need for effective alternative temporary skin replacements . Methods. We cultured human neonatal fibroblasts (HF) for 4 to 6 week s 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 nd quantitated, and growth factor-specif ic messenger RNAs were identified by reverse transcription-polymerase chain reaction. Living grafts (Biobrane/HF) were sutured to full-thick ness, excised wounds on athymic mice; control animals received Biobran e alone. Wounds were observed and biopsy specimens were obtained at in tervals during the subsequent 40 days. Results. After 3 to 6 weeks of culture in Biobrane the HF proliferated and secreted matrix proteins i ncluding type I collagen, fibronectin, and decorin, as well as messeng er RNA for several growth factors (acidic fibroblast growth factor, ba sic fibroblast growth factor, and keratinocyte growth factor). Biobran e/HF grafts were transferred to full-thickness wounds, resulting in ra pid fibrovascular ingrowth from the wound and effective wound closure for up to 40 days with minimal inflammatory responses. Biobrane contro l grafts adhered initially to wounds, but within several days many gra fts developed subgraft exudates; histologic sections revealed marked i nflammatory responses in these wounds. By 20 days, most BB grafts were separating from the underlying wounds that were closing by epithelial ization and contraction. Conclusions. The Biobrane/HF living skin repl acement provides long-term biologic coverage of full-thickness wound d efects in mice with rapid incorporation of a living tissue matrix into the wound bed. Because HF have been found to be relatively nonantigen ic when transferred to allogeneic hosts, Biobrane/HF grafts could repl ace the use of cadaveric allograft skin for achieving temporary wound closure after burn wound excision. Biobrane/HF grafts may persist on h uman wounds for weeks or months, with long-term persistence perhaps pr imarily dependent on durability of the silicone rubber layer.