title: Effect of low shear stress on permeability and occludin expression in porcine artery endothelial cells.
abstract: BACKGROUND
  Although both fluid shear stress and mass transport of atherogenic substances into the vascular wall are known to be important factors in atherogenesis, there has been little research on the effect of shear stress on vascular permeability. Therefore, the effects of shear stress on the permeability of arteries and the expression of the endothelial cell tight junction molecule occludin, an important regulator of vascular permeability, were investigated.
  
  
  METHODS
  Porcine carotid arteries were perfusion cultured ex vivo with low (1.5 dyne/cm(2)) or physiologic (15 dyne/cm(2)) shear stress and 100 mmHg pressure for 24 hours. Subsequently, 20 nm gold particles in solution were infused into the lumen of vessels at 100 mmHg for 30 minutes. Frozen sections were then cut and stained for gold particles. Image analysis was used to determine the density of the particles in the vessel walls. The expression of endothelial cell occludin mRNA and protein were determined using reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting, respectively.
  
  
  RESULTS
  Permeability results showed a 2.8-fold increase in the apparent permeability of vessels cultured with low versus physiologic shear stress. RT-PCR and Western blotting results showed significant decreases in occludin mRNA and protein expression at 12 and 24 hours in vessels cultured with low versus physiologic shear stress.
  
  
  CONCLUSIONS
  These results demonstrate that low shear stress increases vascular permeability in porcine carotid arteries, possibly owing to decreased occludin expression. These results may have implications in the preferential formation of atherosclerotic vascular disease adjacent to branches and bifurcations where low mean shear stresses may occur.
authors: Sections of Leukocyte Biology and Nutrition, Department of Pediatrics, Baylor College of Medicine, Children's Nutrition Research Center, 1100 Bates, Suite 6014, Houston, Texas 77030, USA.
authors: Brian S
authors: BS
authors: Conklin
authors: Raymond P
authors: RP
authors: Vito
authors: Changyi
authors: C
authors: Chen
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002339:Carotid Arteries; D002478:Cells, Cultured; D016228:Endothelial Growth Factors / Q000032:analysis / Q000235:genetics*; D004730:Endothelium, Vascular / Q000737:chemistry / Q000166:cytology / Q000378:metabolism*; D015870:Gene Expression; D007150:Immunohistochemistry; D008222:Lymphokines / Q000032:analysis / Q000235:genetics*; D008565:Membrane Proteins / Q000032:analysis / Q000235:genetics*; D062793:Occludin; D010539:Permeability; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012212:Rheology; D013552:Swine; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
chemical_list: D016228:Endothelial Growth Factors; D008222:Lymphokines; D008565:Membrane Proteins; D062793:Occludin; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors