Author Affiliations: Neurosurgery, Brigham and Women's Hospital and Children's Hospital (Dr Malek), and Departments of Neurosurgery (Dr Malek), Medicine (Drs Alper and Izumo), and Cell Biology (Dr Alper), Harvard Medical School, and Molecular Medicine and Renal Units (Dr Alper), and Cardiovascular Division (Dr Izumo), Beth Israel Deaconess Medical Center, Boston, Mass; and Division of Interventional Neurovascular Radiology, University of California at San Francisco, San Francisco (Dr Malek).
Atherosclerosis, the leading cause of death in the developed world and
nearly the leading cause in the developing world, is associated with systemic
risk factors including hypertension, smoking, hyperlipidemia, and diabetes
mellitus, among others. Nonetheless, atherosclerosis remains a geometrically
focal disease, preferentially affecting the outer edges of vessel bifurcations.
In these predisposed areas, hemodynamic shear stress, the frictional force
acting on the endothelial cell surface as a result of blood flow, is weaker
than in protected regions. Studies have identified hemodynamic shear stress
as an important determinant of endothelial function and phenotype. Arterial-level
shear stress (>15 dyne/cm2) induces endothelial quiescence and
an atheroprotective gene expression profile, while low shear stress (<4
dyne/cm2), which is prevalent at atherosclerosis-prone sites, stimulates
an atherogenic phenotype. The functional regulation of the endothelium by
local hemodynamic shear stress provides a model for understanding the focal
propensity of atherosclerosis in the setting of systemic factors and may help
guide future therapeutic strategies.
Malek AM, Alper SL, Izumo S. Hemodynamic Shear Stress and Its Role in Atherosclerosis. JAMA. 1999;282(21):2035–2042. doi:10.1001/jama.282.21.2035