IntroductionOxidized low density lipoprotein (oxLDL) is a major risk factor in the development of atherosclerotic plaques, which preferentially form at vascular bifurcations subject to bidirectional recirculating disturbed shear stress (DSS).MethodsA microfluidic channel with a step barrier was designed, tested and fabricated to generate atheroprotective unidirectional laminar shear stress (LSS) and atheroprone DSS onto an EC monolayer for 48 hours. EC stiffness was assessed using atomic force microscopy.ResultsOur results show a statistically significant increase in oxLDL uptake in DSS vs. LSS regions in three EC types: human aortic (55% increase), human microvascular (40% increase), and mouse microvascular (50% increase). OxLDL uptake was reduced in cells lacking Cav1, the main protein in caveolae (n=4, p<0.05). The mechanism of differential oxLDL uptake was further investigated using siRNA treated ECs for CD36 and Lox1, two oxLDL receptors. Our experiments revealed that CD36 (n=4, p<0.05), but not Lox1 (n=4, p<0.05), is required for increased uptake under DSS. Furthermore, the increased uptake under DSS results in a 60% increase in EC stiffness (n=3, p<0.05). This data is further supported by ex vivo stiffness measurements of vessels from WT mice which show a 50% increase in EC stiffness in the aortic arch (DSS) than the LSS region of the descending aorta (DA) (n=5, p<0.05). In Cav1 KO mice, EC stiffness was markedly reduced (n=5, p<0.05) and no differences observed between the DA and arch.ConclusionTaken together, this study suggests that DSS‐induced increase in oxLDL uptake is mediated by caveolae and plays a significant role in increasing localized EC stiffness.