Bioartificial skin equivalents are cryopreserved until use, a procedure that may seriously reduce the viability of fibroblasts in the dermal component (Mansbridge et al., 1998). Thus, the dermal matrix of cryopreserved complete skin equivalents may actually be much less cellular when used than when they were constructed, or may even be acellular. The trend today is, in fact, toward the use of much less expensive acellular dermal templates overlaid with MSTSGs or cultured keratino-cytes to induce the regeneration of host dermal tissue as the scaffold degrades (Yannas, 2001). Epidermis and dermal regeneration template can be applied in either a one-step or two-step procedure. In the former, the dermal regeneration template and a MSTSG or kerati-nocytes are placed on the wound together (figure 4.4). However, the epidermal component does not survive well because of the initial lack of vascularization in the template. This problem is overcome in a two-step procedure, where the template is placed on the wound first and allowed to be invaded by fibroblasts and vascular-ize before adding the MSTSG or keratinocytes.
One of the effects shared by dermal regeneration templates and bioartificial skin equivalents is the reduction of wound contraction, which results in reduced
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