Gene expression is altered in perfused arterial segments exposed to cyclicflexure ex vivo

Certain regions of coronary and other arteries undergo cyclic flexure due t o attachment to the heart or crossing of joints. Such motion gives rise to fluctuations in transmural stress and luminal sheer stress. It is well know n that cyclic variation of these biomechanical forces influences many aspec ts of vascular cell biology including gene expression. The purpose of this work was to investigate the hypothesis that cyclic flexure of arterial segm ents influences their gene expression. Bilateral porcine femoral arteries w ere obtained fresh from the abattoir. One vessel was mounted in an ex vivo perfusion system and subjected to an intraluminal pressure of 60 mm Ng and flow of 50 ml/min to serve as a control. The other vessel was mounted in a second perfusion system with similar hemodynamic conditions, but also subje cted to controlled cyclic bending consistent with that found in coronary ar teries in vivo. Reverse transcriptase-polymerase chain reaction analysis de monstrated that E-selectin and matrix metalloproteinase-1 (MMP-1) were cons istently and significantly downregulated in the specimens subjected to 4 h of cyclic bending as compared to the control (n=8, p<0.05). Our results sho w that cyclic flexure of arterial segments in vitro may influence their gen e expression. Further investigation should follow this navel observation an d focus on other known mediators to more carefully elucidate the consequenc e of cyclic flexure on arterial pathobiology. (C) 1999 Biomedical Engineeri ng Society. [S0090-6964(99)01503-9].