16.0: Thursday, March 17, 2005

Creation of a Vascularized Composite Graft with Acellular Dermal Matrix and Hydroxyapatite

Albert S. Woo, MD, Judy L. Jang, BA, Jennifer S. Lee, MD, and Jeffrey Weinzweig, MD.

Purpose: Biomaterials have shown promise as potential substitutes for human tissue. The purpose of this study was to examine the possibility of creating a viable composite graft completely out of biomaterials.

Methods: A 4x2 cm sheet of acellular dermal matrix was enveloped around a square wafer of hydroxyapatite. This was inserted into an extraperitoneal pocket. In Sprague-Dawley rats, the superficial epigastric arteriovenous pedicle was inserted into the biomaterial construct on one side. A second graft was inserted on the opposite side without a pedicle, serving as its control. Animals were divided into groups and sacrificed at 30, 60 and 90 days for tissue harvesting.

Results: Histologic evaluation of specimens was performed using H&E and Trichrome stains. At 30 days, the dermal matrices demonstrated full thickness cellular infiltration in all specimens. The hydroxyapatite implants had slower infiltration of cells. Early specimens showed a high number of inflammatory mediators, followed by cellular proliferation and collagen deposition. Each of these stages was reached earlier in experimental specimens.

Conclusion: These results suggest that provision of an arteriovenous blood supply to non-biologic tissue grafts significantly increases the speed of cellular deposition. These data offer a promising start to a potential new avenue for tissue engineering.