Helmlinger G, Geiger R V, Schreck S, Nerem R M
School of Mechanical Engineering, Georgia Institute of Technology, Atlanta 30332-0405.
J Biomech Eng. 1991 May;113(2):123-31. doi: 10.1115/1.2891226.
Endothelial cells (EC) appear to adapt their morphology and function to the in vivo hemodynamic environment in which they reside. In vitro experiments indicate that similar alterations occur for cultured EC exposed to a laminar steady-state flow-induced shear stress. However, in vivo EC are exposed to a pulsatile flow environment; thus, in this investigation, the influence of pulsatile flow on cell shape and orientation and on actin microfilament localization in confluent bovine aortic endothelial cell (BAEC) monolayers was studied using a 1-Hz nonreversing sinusoidal shear stress of 40 +/- 20 dynes/cm2 (type I), 1-Hz reversing sinusoidal shear stresses of 20 +/- 40 and 10 +/- 15 dynes/cm2 (type II), and 1-Hz oscillatory shear stresses of 0 +/- 20 and 0 +/- 40 dynes/cm2 (type III). The results show that in a type I nonreversing flow, cell shape changed less rapidly, but cells took on a more elongated shape than their steady flow controls long-term. For low-amplitude type II reversing flow, BAECs changed less rapidly in shape and were always less elongated than their steady controls; however, for high amplitude reversal, BAECs did not stay attached for more than 24 hours. For type III oscillatory flows, BAEC cell shape remained polygonal as in static culture and did not exhibit actin stress fibers, such as occurred in all other flows. These results demonstrate that EC can discriminate between different types of pulsatile flow environments.(ABSTRACT TRUNCATED AT 250 WORDS)
内皮细胞（EC）似乎会使其形态和功能适应它们所处的体内血流动力学环境。体外实验表明，暴露于层流稳态流动诱导的剪切应力下的培养内皮细胞也会发生类似的变化。然而，体内的内皮细胞会暴露于脉动流环境中；因此，在本研究中，使用40±20达因/平方厘米的1赫兹非反向正弦剪切应力（I型）、20±40和10±15达因/平方厘米的1赫兹反向正弦剪切应力（II型）以及0±20和0±40达因/平方厘米的1赫兹振荡剪切应力（III型），研究了脉动流对汇合的牛主动脉内皮细胞（BAEC）单层中细胞形状和方向以及肌动蛋白微丝定位的影响。结果表明，在I型非反向流动中，细胞形状变化较慢，但长期来看，细胞比其稳态流动对照呈现出更细长的形状。对于低振幅的II型反向流动，BAEC的形状变化较慢，且始终比其稳态对照更不细长；然而，对于高振幅反向流动，BAEC在24小时内就不再附着。对于III型振荡流动，BAEC细胞形状如静态培养时一样保持多边形，且未表现出肌动蛋白应力纤维，而在所有其他流动中都会出现这种纤维。这些结果表明，内皮细胞能够区分不同类型的脉动流环境。（摘要截取自250字）
