BFGF RELEASE IS DEPENDENT ON FLOW CONDITIONS IN EXPERIMENTAL VEIN GRAFTS

Objectives: Basic Fibroblastic Growth Factor (bFGF) is a powerful mito gen for smooth muscle cells and has been implicated in the genesis of Myointimal hyperplasia. The aim of this study was to determine the rel ease of bFGF by veins in different haemodynamic conditions. Design and setting: Laboratory animal study. Materials: In 39 Lewis rats, a 1 cm long segment of inferior vena cava was inserted at the level of the a bdominal aorta. The segments of inferior vena cava were obtained from syngenic Lewis rats. Arterial Vein Grafts (AVG) were harvested after 4 weeks (AVG4) and 12 weeks (AVG 12). In 16 animals the arterial vein g rafts were explanted 4 weeks after the initial operation and reimplant ed (Reimplanted Vein Grafts: RVG) in syngenic Lewis rats as venous-ven ous bypass grafts at the level of the left iliac vein and harvested af ter 2 weeks (RVG2) and 8 weeks (AVG 8). Outcome measures: The tissue w as studied in organ culture in a serum-free system for (1) release of bFGF (immunoassay) and (2) mitogenic activity of the conditioned media . Scanning electron and light microscopy studies were also performed. Results: bFGF release by veins increased significantly (p < 0.01) when veins were inserted in the arterial circulation, and decreased signif icantly (p < 0.01) when grafts where reimplanted in the venous system. bFGF release (ng/cm(2)): [GRAPHICS] Conclusion: Vein inserted in the arterial circulation release a higher quantity of bFGE This could expl ain in part, the formation of myointimal hyperplasia in arterial vein graft.