Acceleration of soft tissue repair by a thrombin-derived oligopeptide

Augmentation of thrombin-modulated chemotaxis and mitogenic activity within the early phase of soft tissue repair is now possible. Identification of high-affinity thrombin receptor binding domains within thrombin has enabled the synthesis of a family of peptides which interact with thrombin receptors and enhance in vitro mitogenesis. A single (5.0 μg/wound) application of the thrombin receptor-activating peptide (P^517-30) significantly increased wound breaking strength from Day 5 (31% over controls) to Day 12. Two models of impaired healing created by radiotherapy (RT) were used to elucidate possible mechanisms of P^517-30 action. Although P^517-30 did not completely overcome the RT-induced healing impairments, it increased breaking strength under conditions of penetrating whole body RT-induced pancytopenia by 22% and of nonpenetrating surface RT-induced dermal cell damage by 42%. This suggests that P^517-30 directly stimulates resident endothelial cells, fibroblasts, or other cells to overcome dermal and circulating monocytic deficits. These results suggest a method to accelerate wound healing with potential clinical applications and emphasize the activity of thrombin as a growth factor.