EFFECT OF INTRAARTERIAL ENVIRONMENT ON ENDOTHELIALIZATION AND BASEMENT-MEMBRANE ORGANIZATION IN POLYTETRAFLUOROETHYLENE GRAFTS

PURPOSE: To determine if a complete intra-arterial environment affects endothelialization rate and basement membrane organization in polytet rafluoroethylene (PTFE) grafts. METHOD: Thirty dogs underwent either i nfrarenal abdominal aorta PTFE interposition (12) or intraluminal sten ted (18) grafting. Grafts were explanted at 4 and 8 weeks and rate of endothelial ingrowth calculated, Endothelial cells were identified and basement membrane organization assessed using antibodies against endo thelial cell-specific surface antigen CD31, type IV collagen, and lami nin. RESULTS: Endothelialization rates, expressed as percent graft sur face area coverage per week, were 3.7% +/- 0.62% (4-week control), 12. 9% +/- 0.58% (4-week stented), 4.2% +/- 0.62% (8-week control), and 10 .0% +/- 0.54% per week (8-week stented grafts), Endothelial repaving r ates were constant for control and increased in all stented grafts (P <0.01), At 4 weeks, laminin was identified in all control (6 of 6) and no stented grafts. Staining was confined to the 20% of the hyperplast ic intimal area immediately below the endothelium. At 4 weeks, type IV collagen was present throughout the entire hyperplastic intima in con trol specimens but was confined to a discrete subendothelial zone in s tented grafts. By 8 weeks, type IV collagen became concentrated in the luminal one third of the intima in control grafts. CONCLUSION: Intra- arterial graft location is associated with early formation of an organ ized basement membrane and accelerated endothelialization in PTFE graf ts. (C) 1997 by Excerpta Medica, Inc.