NF-κB and hemodynamics in regions predisposed and protected from atherosclerosis. Schematic of hemodynamics in the human carotid bifurcation. The straight segment of the artery proximal to the bifurcation is typical of regions resistant to atherogenesis (left). These regions are associated with a uniformly laminar blood flow profile that may induce the expression of various classes of atheroprotective genes. Examples of each class from the work of Akimoto et al. (46) and Gimbrone and coworkers (42) are shown (below left). It is not known whether this class of genes is coordinately regulated. In contrast, disturbed laminar flow, with boundary layer separation, flow reversal, secondary flows, and shifting stagnation points, is typical of regions predisposed to atherosclerosis (right). In these regions, the mean shear stress is relatively low and the NF-κB signal transduction pathway may be primed for activation. Systemic risk factors would therefore preferentially induce the expression of proatherogenic NF-κB–dependent genes at lesion-predisposed sites. Examples of each class are provided (below right).