Differential responsiveness of early- and late-passage endothelial cells to shear stress.
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.
Kudo
Fabio A
FA
Department of Surgery, Yale University School of Medicine, Boyer Center for Molecular Medicine, 295 Congress Ave., New Haven, CT 06519, USA.
Warycha
Bohdan
B
Juran
Peter J
PJ
Asada
Hidenori
H
Teso
Desarom
D
Aziz
Faisal
F
Frattini
Jared
J
Sumpio
Bauer E
BE
Nishibe
Toshiya
T
Cha
Charles
C
Dardik
Alan
A
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
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