title: Differential responsiveness of early- and late-passage endothelial cells to shear stress.
abstract: BACKGROUND
  The incidence of vascular disease increases with age. Because atherosclerosis and neointimal hyperplasia colocalize in areas of disturbed shear stress, the effects of orbital shear stress (SS) on endothelial cell proliferation, protein kinase B (Akt) activation, and functional activity were analyzed using a senescence model.
  
  
  METHODS
  Early- (p3 to 7) and late- (p28 to 32) passage bovine aortic endothelial cells were exposed to orbital SS (210 rpm) or static conditions (0 to 5 days). Cell proliferation was directly counted and confirmed with proliferating cell nuclear antigen reactivity. Phosphorylated and total Akt were assessed with Western blotting. Endothelial cell-induced smooth muscle cell migration was assessed with a Boyden chamber.
  
  
  RESULTS
  Late-passage endothelial cells demonstrated no increase in orbital SS stimulated proliferation compared with early-passage cells (P = .42). Late-passage endothelial cells demonstrated decreased Akt phosphorylation in response to SS compared with early passage cells (n = 6, P = .01). Late-passage cells induced 26% less smooth muscle cell migration than early-passage cells (n = 3, P = .03).
  
  
  CONCLUSIONS
  Late-passage endothelial cells demonstrate decreased proliferation, Akt phosphorylation, and secretion of smooth muscle cell chemoattractants in response to orbital SS compared with early passage cells. These results suggest that late-passage endothelial cells respond to SS differently than early-passage cells and confirm the utility of the in vitro senescence model.
authors.affiliation: Department of Surgery, Yale University School of Medicine, Boyer Center for Molecular Medicine, 295 Congress Ave., New Haven, CT 06519, USA.
authors.forename: Fabio A
authors.initials: FA
authors.lastname: Kudo
authors.forename: Bohdan
authors.initials: B
authors.lastname: Warycha
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Juran
authors.forename: Hidenori
authors.initials: H
authors.lastname: Asada
authors.forename: Desarom
authors.initials: D
authors.lastname: Teso
authors.forename: Faisal
authors.initials: F
authors.lastname: Aziz
authors.forename: Jared
authors.initials: J
authors.lastname: Frattini
authors.forename: Bauer E
authors.initials: BE
authors.lastname: Sumpio
authors.forename: Toshiya
authors.initials: T
authors.lastname: Nishibe
authors.forename: Charles
authors.initials: C
authors.lastname: Cha
authors.forename: Alan
authors.initials: A
authors.lastname: Dardik
mesh_terms: D000375:Aging / Q000502:physiology; D000818:Animals; D001011:Aorta / Q000166:cytology; D017209:Apoptosis / Q000502:physiology; D015153:Blotting, Western; D002417:Cattle; D002452:Cell Count; D002455:Cell Division / Q000502:physiology; D049109:Cell Proliferation; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000502:physiology; D066298:In Vitro Techniques; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000502:physiology; D010766:Phosphorylation; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D033081:Shear Strength; D013314:Stress, Mechanical; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
chemical_list: D018809:Proliferating Cell Nuclear Antigen; D011518:Proto-Oncogene Proteins; D016159:Tumor Suppressor Protein p53; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt