Dermal regeneration in native non-cross-linked collagen sponges with different extracellular matrix molecules

Collagenous dermal templates can prevent scarring and wound contraction in the healing of full-thickness defects. In a porcine wound model, full-thickness wounds were substituted by reconstituted and native collagen sponges in combination with autologous split-skin mesh grafts and covered with a semipermeable wound membrane. Native collagen sponges were also linked with either hyaluronic acid, elastin, or fibronectin. Reconstituted collagen matrixes, composed of cross-linked small collagen fibrils, disintegrated within a week and did not contribute to dermal regeneration, whereas native collagen matrixes, composed of intact collagen fibers, disintegrated within 2 weeks and did contribute to dermal regeneration. Addition of extracellular matrix proteins retarded the disintegration to 4 weeks. However, fibronectin-treated matrixes caused aberrant epithelization. When hyaluronic acid was added, matrixes were invaded by more fibroblasts and myofibroblasts. This process correlated with fibrosis and wound contraction. In contrast, the native collagen/elastin matrix reduced the amount of fibroblasts and myofibroblasts. This latter matrix resulted in optimal dermal regeneration and little wound contraction.