The role of circulating cells in the healing of vascular prostheses.

Purpose: Cells covering the flow surface of vascular prostheses are derived in part from endothelium of adjacent native artery and from capillaries that extend through the pores of the graft. This study is designed to determine whether these endothelial-like cells can also originate from circulating blood cells and if so to identify them with protein markers.

Methods: Pledgets of vascular graft material were suspended within the aortas of dogs with metal stents that isolated the pledgets from the aortic wall. Explanted pledgets were examined for cells containing factor VIII-related antigen and other markers identified with monoclonal antibodies.

Results: A monolayer of cells that stained positive for factor VIII formed on pledgets after 7 days. Pledgets removed after 55 days had endothelial cells, smooth muscle cells, macrophages, monocytes, and capillary-like structures which were identified by staining for the monoclonal antibodies 43 beta E3 (vimentin), HHF35 (alpha and gamma muscle actin), CGA7 (smooth muscle actin), and HAM56 (macrophage). Woven and knitted polyester and extruded polytetrafluoroethylene pledgets healed in a similar manner.

Conclusion: The origin of the cells identified is speculative but they appear to have been derived from circulating cells, possibly stem cells, which are capable of differentiation because the pledgets on which the cells were identified were isolated from aortic wall endothelium and perivascular capillaries.