James W. Polarek

Characterization of a hyaluronic acid-Arg-Gly-Asp peptide cell attachment matrix

We have developed a method to modify cross-linked hyaluronic acid with peptides containing the Arg-Gly-Asp sequence. The material created by this process is a three-dimensional porous matrix capable of supporting integrin receptor-mediated cell attachment. Peptide density can be controlled by varying the reaction conditions during peptide immobilization. Following cell attachment, cells actively proliferate and colonize the pores of the matrix. This material should prove useful for the maintenance of cells on a chemically defined three-dimensional substrate or as a scaffold for enhancing tissue repair.

Effects of an arginine-glycine-aspartic acid peptide-containing artificial matrix on epithelial migration in vitro and experimental second-degree burn wound healing in vivo.

Cells central to dermal tissue repair such as dermal fibroblasts and keratinocytes interact with arginine-glycine-aspartic acid (RGD)-containing proteins of the extracellular matrix such as fibronectin. It has been shown that synthetic peptides containing this RGD sequence can also support cell attachment and migration in vitro. We therefore set out to test whether the use of these peptides, when formulated as a synthetic RGD-peptide matrix consisting of peptide complexed with hyaluronic acid, would have an effect on the rate of epithelial migration and healing of experimental wounds. Evaluation consisted of measuring he extent of epithelial outgrowth from human dermal explants and the epithelization of experimental second-degree burn wounds in pigs. We show here that the RGD-peptide matrix supports epithelial sheet migration from explants in a dose-dependent manner. In second-degree burn wounds in pigs, wounds treated with daily applications of the RGD-peptide matrix under occlusion resurfaced at a significantly faster rate (day 7 = 57% completely epithelized) than wounds treated with hyaluronic acid under occlusion (day 7 = 13% completely epithelized, p < 0.01), occlusion alone (day 7 = 13% completely epithelized, p < 0.01), or air exposed (day 7 = 0% completely epithelized, p < 0.001). Histologic examination showed that wounds treated with the RGD-peptide matrix also had thicker epithelial covering and greater granulation tissue deposition than occluded, air-exposed, and hyaluronate-treated wounds. These data therefore show that the use of RGD-peptide matrix induces faster explant epithelial migration and results in faster healing of experimental second-degree burns.