title: Effects of different types of fluid shear stress on endothelial cell proliferation and survival.
abstract: We attempted to clarify the effect of different types of shear stress on endothelial cell (EC) proliferation and survival. Bovine aortic ECs were subjected to either steady laminar, 1 Hz pulsatile, or 1 Hz to and fro shear at 14 dyne/cm(2). % of BrdU positive EC was 14.3 +/- 1.6% in steady, 21.5 +/- 3.2% in pulsatile, and 11.4 +/- 2.4% in to and fro after 4 h, respectively (P < 0.05). Pulsatile shear compared with static control. Rapamycin reduced BrdU incorporation in all shear regimens (P < 0.001). However, it was still higher in EC exposed to pulsatile shear than the other regimens (P < 0.005). PD98059 completely abolished the increased BrdU incorporation in all shear regimens, including pulsatile shear. Pulsatile shear had significantly elevated ERK1/2 phosphorylation at 5 min compared with steady (P < 0.05) and to and fro shear (P < 0.01) while there was no significant difference in pp70(S6k) phosphorylation between any shear regimen. The ratio of apoptotic cells in serum deprived EC in the presence of steady laminar, pulsatile and to and fro shear for 4 h were 2.7 +/- 0.78%, 2.7 +/- 0.42%, and 2.9 +/- 0.62%, respectively while after the addition of serum for 4 h, it was 4.3 +/- 0.73%. All shear regimens phosphorylated AKT in a time-dependent manner with no significant difference between regimens. Our results demonstrate that different types of shear stress regimens have different effects on EC and may account for the variable response of EC to hemodynamics in the circulation.
authors.affiliation: Department of Surgery, Section of Vascular Surgery, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Kadohama
authors.forename: Kengo
authors.initials: K
authors.lastname: Nishimura
authors.forename: Yuji
authors.initials: Y
authors.lastname: Hoshino
authors.forename: Tadahiro
authors.initials: T
authors.lastname: Sasajima
authors.forename: Bauer E
authors.initials: BE
authors.lastname: Sumpio
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology; D001696:Biomechanical Phenomena; D002352:Carrier Proteins / Q000378:metabolism; D002417:Cattle; D049109:Cell Proliferation; D002470:Cell Survival / Q000502:physiology; D042783:Endothelial Cells / Q000166:cytology / Q000502:physiology*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3