The recovery of skin function is the goal of each
burn surgeon. Split-skin graft treatment of full-thickness skin defects leads to
scar formation, which is often vulnerable and instable. Therefore, the aim of this study was to analyze wound healing and
scar tissue formation in acute full-thickness
wounds treated with clinically available
biopolymer dermal regeneration templates. Full-thickness
wounds (3 x 3 cm) on both flanks of Gottingen mini pigs (n= 3) were treated with split-thickness skin graft alone or in combination with a 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) cross-linked-
collagen scaffold, Integra, or a polyethyleneglycol
terephthalate-
polybutylene terephthalate (PEGT/PBT) scaffold. The
wounds (n= 12 per group) were examined weekly for six weeks to evaluate graft take, contraction (planimetry), and cosmetic appearance. Histologic samples taken after one and six weeks were used to assess scaffold angiogenesis, biocompatibility, and
scar tissue quality. In all
wounds, one week postwounding graft take was between 93 and 100 percent. The control
wound, treated with split-skin graft, showed little granulation tissue formation, whereas the EDC-
collagen treated
wounds showed two to three times more granulation tissue formation. The
collagen scaffold was completely degraded within one week. The Integra and PEGT/PBT scaffolds showed angiogenesis only through two-thirds of the scaffold, which resulted in loss of integrity of the epidermis. Only basal cells survived, proliferated, and regenerated a fully differentiated epidermis within three weeks. Granulation thickness was comparable to
collagen scaffold-treated
wounds. After six weeks, control
wounds showed a
wound contraction of 27.2 +/- 6.1 percent, Integra-treated
wounds 34.6 +/- 6.4 percent,
collagen scaffold-treated
wounds 38.1 +/- 5.0 percent, and PEGT/PBT scaffold-treated
wounds 54.5 +/- 3.9 percent. The latter
wounds had significantly more contraction than
wounds of other treatment groups. Microscopically, the control and
collagen scaffold-treated
wounds showed an immature
scar tissue that was two times thicker in the EDC-
collagen treated
wounds. The Integra-treated
wounds showed nondegraded
collagen scaffold fibers with partly de novo dermal tissue formation and partly areas with giant cells and other inflammatory cells. The PEGT/PBT scaffold was almost completely degraded. Scaffold particles were phagocytosized and degraded intracellularly by clusters of macrophages. The
scar tissue was in the early phase of ECM remodeling. In conclusion, this study showed that the rate of dermal tissue formation and
scarring is influenced by the rate of scaffold angiogenesis, degradation, and host response induced by the scaffold materials.