Fibroblast-collagen sponge interactions and the spatial deposition of newly synthesized collagen fibers in vitro and in vivo.

Fibroblast-collagen sponge interactions were studied in cell culture and dermal wound systems. In both models fibroblasts appear to adhere, attach and orient in the presence of type I collagen fibrils. In the presence of fibronectin, purified from bovine blood, adhesion and alignment of fibroblasts appeared to be enhanced as well as the deposition of thick collagen fibers. When collagen sponges were grafted onto full thickness dermal wounds the granulation tissue that was laid down within the collagen sponge appeared to differ from granulation tissue laid down below the collagen sponge or on similar wounds in the absence of a sponge. In the absence of a collagen sponge the granulation tissue is characterized by wavy collagen fibers that exhibit an extinction pattern characteristic of crimped fibers found in tendon when examined under polarized light. In contrast, collagen fibers laid down within the sponge appear to be highly oriented and lack evidence of crimp. These results suggest that the presence of a collagen matrix acts as a template that allows for the organized spatial deposition of newly synthesized collagen fibers. The enhanced biosynthesis of thick collagen fibers in the presence of a collagen sponge containing fibronectin may decrease the remodeling phase that is associated with dermal scarring.