Differential effects of orbital and laminar shear stress on endothelial cells
Differential effects of orbital and laminar shear stress on endothelial cells
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DOI：
10.1016/j.jvs.2005.01.020
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发表时间：
2005-05-01
影响因子：
4.3
通讯作者：
Sumpio, BE
中科院分区：
文献类型：
--
作者：
Dardik, A;Chen, LL;Sumpio, BE
目的：层流切应力对内皮细胞具有动脉粥样硬化保护作用，而非层流、扰动或振荡切应力与动脉粥样硬化和新生内膜增生的发展相关。比较轨道剪切力和层流剪切力对EC形态、增殖和凋亡的影响。将EC暴露于使用定轨振荡器（210 rpm）的定轨剪切应力或使用平行板的层流剪切应力（14 dyne/cm（2））。用光学测速仪测量了振动筛内的剪切应力。直接计数和增殖细胞核抗原染色评估细胞增殖;转移酶介导的脱氧尿苷三磷酸缺口末端标记染色评估细胞凋亡。细胞表面E-选择素和细胞间粘附分子的表达进行了评估与荧光激活细胞分选。蛋白质印迹法检测Akt磷酸化水平。轨道剪切应力使EC增殖增加29%，（3）[H]胸苷掺入增加两倍，而层流剪切应力处理的EC分别减少16%和38%（P 0.0001和P = 0.03，方差分析）。培养孔周边的细胞与剪切应力方向对齐，类似于层流剪切应力下观察到的形状变化，而孔中心的EC似乎与未暴露于剪切应力的EC不对齐。培养孔底部表面的剪切应力在孔中心（5达因/cm（2））比周边（11达因/cm（2））降低;雷诺数为2066。在威尔斯孔的中心和外围差异地接种EC。EC在中心的井有增加的增殖，增加凋亡，减少Akt磷酸化，增加细胞间粘附分子的表达，并减少E-选择素下调，与EC在外围的well.Conclusion：虽然定轨摇床不适用于均匀的剪切应力在整个培养井，动脉的剪切应力的幅度是存在于外围的井。在暴露于低幅度的眼眶剪切应力的中心培养的EC可能是“活化”EC phenotype.Clinical Relevance的模型：理想的体外模型，研究和评估动脉粥样硬化和新生内膜增生的治疗方法是不存在的。大量的文献描述了层流剪切应力对内皮细胞的影响，有助于我们理解剪切应力和血管之间的相互作用。层流剪应力是动脉粥样硬化保护，而振荡或干扰剪应力与动脉粥样硬化和新生内膜增生的地区在体内。这项研究描述了轨道剪切应力模型，其对内皮细胞增殖和凋亡的影响，并表明，激活细胞内Akt通路与这些不同的影响，层流和轨道剪切应力对内皮细胞。
Objective: Laminar shear stress is atheroprotective for endothelial cells (ECs), whereas nonlarninar, disturbed, or oscillatory shear stress correlates with development of atherosclerosis and neointimal hyperplasia. The effects of orbital and laminar shear stress on EC morphology, proliferation, and apoptosis were compared.Methods. ECs were exposed to orbital shear stress with an orbital shaker (210 rpm) or laminar shear stress (14 dyne/cm(2)) with a parallel plate. Shear stress in the orbital shaker was measured with optical velocimetry. Cell proliferation was assessed with direct counting and proliferating cell nuclear antigen staining; apoptosis was assessed with transferase-mediated deoxyuridine triphosphate nick end labeling staining. Cell surface E-selectin and intercellular adhesion molecule expression were assessed with fluorescence-activated cell sorting. Akt phosphorylation was assessed with Western blotting.Results. Orbital shear stress increased EC proliferation by 29% and (3)[H]thymidine incorporation two-fold compared to 16% and 38% decreases, respectively, in ECs treated with laminar shear stress (P < .0001 and P = .03, analysis of variance). Cells in the periphery of the culture well aligned to the direction of shear stress similar to the shape change seen with laminar shear stress, whereas ECs in the center of the well appeared unaligned similar to ECs not exposed to shear stress. Shear stress at the bottom surface of the culture well was reduced in the center of the well (5 dyne/cm(2)) compared to the periphery (11 dyne/cm(2)); the Reynolds' number was 2066. ECs were seeded differentially in the center and periphery of the wells. ECs in the center of the well had increased proliferation, increased apoptosis, reduced Akt phosphorylation, increased intercelluar adhesion molecule expression, and reduced E-selectin down-regulation, compared with ECs in the periphery of the well.Conclusion: Although the orbital shaker does not apply uniform shear stress throughout the culture well, arterial magnitudes of shear stress are present in the periphery of the well. ECs cultured in the center of the well exposed to low magnitudes of orbital shear stress might be a model of the "activated" EC phenotype.Clinical Relevance: The perfect in vitro model to study and assess treatments for atherosclerosis and neointimal hyperplasia does not exist. An extensive body of literature describing effects of laminar shear stress on endothelial cells has contributed to our understanding of the interactions between shear stress and blood vessels. Laminar shear stress is atheroprotective, whereas oscillatory or disturbed shear stress correlates with areas of atherosclerosis and neointimal hyperplasia in vivo. This study describes the orbital shear stress model, its effects on endothelial cell proliferation and apoptosis, and suggests that activation of the intracellular Akt pathway is associated with these differing effects of laminar and orbital shear stress on endothelial cells.