| Objective:Pericardial patches are commonly used in vascular surgery to close arteriotomies. The mechanism of early healing after patch implantation is still not well defined. We used a rat aortic patch model to assess pericardial patch healing and examined Ephrin-B2, a marker of arterial identity, expression within the post-implantation patch. We also determined whether endothelial progenitor cells (EPC) are associated with early patch healing in the arterial environment.Methods:Wistar rats (200-250grams) underwent infrarenal aortic arteriotomy and then closure via bovine or porcine pericardial patch angioplasty. Control groups included subcutaneously implanted patches. Patches were harvested at0-30days and analyzed by histology, immunohistochemistry, immunofluorescence and Western blot as well as quantitative PCR.Results:Prior to implantation, pericardial patches are largely composed of collagen and are acellular. Following implantation, increasing numbers of Ephrin-B2and CD34dual-positive cells are found within the patch, whereas the infiltrating cells are negative for vWF, α-actin, or CD68; porcine patches have a luminal monolayer of cells at day7, compared to bovine patches that do not have any luminal cells. Subcutaneously implanted patches do not attract Ephrin-B2/CD34-positive cells. By day30, both bovine and porcine pericardial patches develop a neointima that contains Ephrin-B2, CD34, and VEGFR2-positive cells.Conclusion:Ephrin-B2and CD34dual-positive cells infiltrate the pericardial patch early after implantation. Arteriotomy closure via pericardial patch angioplasty heals via a process that involves vessel adaptation to the arterial environment that may involve localization of EPC. Arterial remodeling of pericardial patches support endothelialization and may represent a paradigm of healing of scaffolds used for tissue engineering. |
PDF Full Text Request