LAUSR

OBJECTIVES Short-chain acyl-CoA dehydrogenase (SCAD), a key enzyme in the fatty acid oxidation process, is not only involved in ATP synthesis but also regulates the production of mitochondrial reactive oxygen species (ROS) and nitric oxide synthesis. The purpose of this study was to investigate the possible role of SCAD in hypertension-associated vascular remodelling. METHODS In-vivo experiments were performed on spontaneously hypertensive rats (SHRs, ages of 4 weeks to 20 months) and SCAD knockout mice. The aorta sections of hypertensive patients were used for measurement of SCAD expression. In-vitro experiments with t-butylhydroperoxide (tBHP), SCAD siRNA, adenovirus-SCAD (MOI 90) or shear stress (4, 15 dynes/cm2) were performed using human umbilical vein endothelial cells (HUVECs). RESULTS Compared with age-matched Wistar rats, aortic SCAD expression decreased gradually in SHRs with age. In addition, aerobic exercise training for 8 weeks could significantly increase SCAD expression and enzyme activity in the aortas of SHRs while decreasing vascular remodelling in SHRs. SCAD knockout mice also exhibited aggravated vascular remodelling and cardiovascular dysfunction. Likewise, SCAD expression was also decreased in tBHP-induced endothelial cell apoptosis models and the aortas of hypertensive patients. SCAD siRNA caused HUVEC apoptosis in vitro, whereas adenovirus-mediated SCAD overexpression (Ad-SCAD) protected against HUVEC apoptosis. Furthermore, SCAD expression was decreased in HUVECs exposed to low shear stress (4 dynes/cm2) and increased in HUVECs exposed to 15 dynes/cm2 compared with those under static conditions. CONCLUSION SCAD is a negative regulator of vascular remodelling and may represent a novel therapeutic target for vascular remodelling. SUPPLEMENTAL GRAPHICAL ABSTRACT http://links.lww.com/HJH/C151.