title: Morphological evidence for a change in the pattern of aortic wall shear stress with age.
abstract: OBJECTIVE
  The distribution of atherosclerosis around branch sites changes with age in human and rabbit aortas. We tested whether that reflects a change in the pattern of wall shear stress by examining shear-dependent morphological features of endothelial cells.
  
  
  RESULTS
  Endothelial cells and their nuclei align and elongate with applied shear. These parameters were examined in the descending thoracic aorta of immature and mature rabbits. The use of Häutchen preparations, fluorescent stains, and automated image analysis allowed nuclear morphology to be mapped reliably at high resolution over large areas. Cells and their nuclei were most elongated downstream of branch ostia in immature aortas but upstream of them in mature aortas. Elongation was generally greater in mature animals, and nuclei aligned toward the ostia more in these animals, consistent with a greater flow into the branch. Morphology away from branches was indicative of helical flow in the aorta, with greatest shear on the dorsal wall, at both ages.
  
  
  CONCLUSIONS
  The data are consistent with age-related changes in the pattern of shear around aortic branches. Maps of nuclear elongation closely resembled maps of lesion frequency. The association was positive, implying that lesions occur at sites of high shear stress at both ages.
authors.affiliation: Department of Bioengineering, Imperial College London, London, United Kingdom.
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Bond
authors.forename: Saadia
authors.initials: S
authors.lastname: Iftikhar
authors.forename: Anil A
authors.initials: AA
authors.lastname: Bharath
authors.forename: Peter D
authors.initials: PD
authors.lastname: Weinberg
mesh_terms: D000367:Age Factors; D000375:Aging; D000818:Animals; D001013:Aorta, Thoracic / Q000473:pathology* / Q000503:physiopathology; D050197:Atherosclerosis / Q000473:pathology* / Q000503:physiopathology; D053144:Cell Nucleus Shape; D048430:Cell Shape; D042783:Endothelial Cells / Q000473:pathology*; D006439:Hemodynamics; D008297:Male; D011817:Rabbits; D012039:Regional Blood Flow; D013314:Stress, Mechanical