CELLULAR-ORIGIN AND RATE OF ENDOTHELIAL-CELL COVERAGE OF PTFE GRAFTS

To determine the origin, cell type present, and rate of endothelial ce ll coverage of PTFE grafts, 5-cm segments of 4-mm-diameter, 60-mu m PT FE grafts were implanted end-to-end bilaterally in the carotid arterie s of greyhound dogs. An external jugular vein wrap was applied to the outer surface of one of the PTFE grafts; the contralateral PTFE graft, which was unwrapped, served as its control. Two dogs each were sacrif iced at 3, 5, 7, 14, 21, 28, and 35 days postimplantation. Anastomotic endothelial ingrowth was analyzed using scanning electron microscopy. Microvessel ingrowth was documented in longitudinal H&E sections. Cel l identity was established by immunohistochemistry with factor VIII an tibody, Ulex europaes, leukocyte common antigen, and antibodies to alp ha-actin, desmin, vimentin, and basic fibroblast growth factor. All gr afts were patent at the time of harvest. Endothelial cell migration fr om the native artery adjacent to the anastomosis commenced at 7 days, extended to 5 mm beyond the proximal and distal anastomoses by 14 days and to 1.0 cm by 35 days. Endothelialization of the mid-portion of th e wrapped grafts occurred via microvessel ingrowth, a process which be gan at 7 days. Microvessels reached the luminal surface by 28 days and an endothelial cell monolayer was established by 35 days. Wrapping th e external surface of the graft with vein increased the rate of graft healing. Basic fibroblast growth factor was detectable by immunohistoc hemistry at the vein wrap-graft interface in the first 14 days. (C) 19 95 Academic Press,Inc.