Histologic and immunohistochemical features in biopsy sites in which bovine collagen matrix was used for hemostasis

Background: Bovine collagen matrix (Helistat and Helatene), which is used primarily for hemostasis, decreases wound contracture in skin biopsy sites and promotes wound granulation. Objective: Our purpose was to evaluate excision specimens of previous biopsy sites to determine whether there are histologic differences between cases in which bovine collagen matrix was used for hemostasis and those in which it was not used. Methods: Thirty-two diagnostic punch biopsies were done with hemostasis obtained with bovine collagen matrix in 24 biopsies and by pressure alone in eight, The biopsy sites were reexcised at various time intervals, and the histologic and immunohistochemical features were evaluated and compared. Results: In specimens in which collagen matrix was used, migration of stromal and epithelial cells along the bovine collagen matrix was evident by 2 days and had progressed rapidly by 4 days. Around and within the matrix hyaluronic acid increased during the first 8 to 10 days. Initially stromal cells stained with CD34 and reticulum fibers were present at 8 to 10 days. At 12 to 15 days, factor XIIIa(+) stromal cells were present within the matrix, and host collagen fibers were present and well-oriented within the degenerating matrix. Biopsy specimens allowed to heal without the matrix showed a delayed and an uneven increase in hyaluronic acid. Furthermore, the granulation tissue within the dermis showed no organization with a persistent acute inflammatory infiltrate and increased muscle actin-positive stromal cells as scar formation proceeded. Conclusion: Bovine collagen products appear to provide a matrix that promotes thrombosis, The collagen matrix also promotes migration and attachment of stromal and epithelial cells, thereby organizing and accelerating wound healing.