EFFECT OF ENDOLUMINAL PTFE GRAFT PLACEMENT ON CELL-PROLIFERATION, PDGF SECRETION, AND INTIMAL HYPERPLASIA

To determine the effects of intraluminal placement on peri-anastomotic intimal hyperplasia and platelet derived growth factor (PDGF) secreti on in polytetrafluoroethylene (PTFE) grafts. Infrarenal aortic PTFE gr afts were placed in 30 dogs as either interposition (n = 12) or intral uminal stented (n = 18) grafts. Grafts were explanted at 4 and 8 weeks . Bt each anastomosis, intima to media height ratios (IMHR) were calcu lated, and smooth muscle (Actin), proliferating (PCNA), and PDGF secre ting cell content determined using cell-specific immunohistochemical s tains. At the proximal anastomosis, control and stented graft; IMHRs w ere 1.01 +/- 0.16 vs 0.59 +/- 0.18 iu 4-week and 1.42 +/- 0.16 vs 0.50 +/- 0.14 in 8-weeks specimens. Similar IMHR values were present for t he distal anastomosis. Peri-anastomotic PCNA cell counts were greater in control grafts at both 4 and 8 weeks. Stented grafts were associate d with diminished IMHR, and PCNA+ content at both 4 and 8 weeks (P < 0 .05). PDGF+ content was similar among control and stented grafts at 4 weeks, while lower in stented grafts at 8 weeks (P < 0.05). At the dis tal anastomosis, a correlation between PDGF secretion and Actin+ cell content was observed in control grafts at 4 (r = 0.74) and 8 (r = -0.5 6) weeks. Cell proliferation was associated with PDGF content in 4-wee k intraluminal and 8-week control grafts (P < 0.05). changes in IMHR w ere not the result of differential PDGF secretion. Intraluminal locati on attenuates intimal hyperplasia in PTFE grafts. The reduced intimal hyperplasia and improved healing of endoluminal grafts could not be at tributed to lower PDGF content alone. (C) 1996 Academic Press Inc.