Evaluation of dermal-epidermal skin equivalents ('composite-skin') of human keratinocytes in a collagen-glycosaminoglycan matrix (Integra (TM) Artificial Skin)

Integra(TM) artificial skin (Integra LifeSciences Corp., Plainsboro, NJ, US A) is a dermal template consisting of bovine collagen, chondroitin-6-sulpha te and a silastic membrane manufactured as Integra(TM). This product has ga ined widespread use in the clinical treatment of third degree burn wounds a nd full thickness skin defects of different aetiologies.(1,2) The product w as designed to significantly reduce the time needed to achieve final wound closure in the treatment of major burn wounds, to optimise the sparse autol ogous donor skin resources and to improve the durable mechanical quality of the skin substitute. The clinical procedure requires two stages. The first step creates a self neodermis, the second creates a self epidermis on the neodermis. However, it is desirable to cover major burn wounds early in a s ingle step by a skin substitute consisting of a dermal equivalent seeded in vitro with autologous keratinocytes ('composite-skin') out of which a full thickness skin develops-in vivo. The goal of this experimental study was t o develop a method to integrate human keratinocytes in homogenous distribut ion and depth into Integra(TM) Artificial Skin. The seeded cell-matrix comp osites were grafted onto athymic mice in order to evaluate their potential to reconstitute a human epidermis in vivo. We were able to demonstrate that the inoculated human keratinocytes reproducibly displayed a homogenous pat tern of distribution, adherence, proliferation and confluence. The cell-mat rix composites grafted in this model exhibited good wound adherence, comple te healing, minor wound contraction and had the potential to reconstitute a n elastic, functional and durable human skin. Histologically we were able t o show that the inoculated human keratinocytes in vivo colonised the matrix in a histomorphologically characteristic epidermal pattern (keratomorula, keratinocyte bubbling) and developed a persisting, stratified, keratinising epidermis which immunohistologically proved to be of human origin. These e xperimental results demonstrate the establishment of an effective cell cult ivation process which may be suitable for scale-up production of the epider mal component as large scale composite-skin grafts. When seeded into Integr a(TM) and grafted onto the nude mouse a replacement skin with normal functi oning dermal-epidermal components was developed. These results encourage th e design of a clinical trial to assess the function of this composite graft in man. (C) 2000 The British Association of Plastic Surgeons.