Introduction

Endothelial cells (ECs) morphology strongly depends on the imposed mechanical stimuli. These mechanical stimuli include wall shear stress (WSS) and biaxial cyclic stretches (CS). Under combined loading, the effect of CS is not as simple as pure CS. The present study investigates the morphological response of ECs to the realistic mechanical stimuli.

Methods

The cell population is theoretically studied using our previous validated model. The mechanical stimuli on ECs are described using four parameters; WSS magnitude (0 to 2.0 Pa), WSS angle (− 50° to 50°), and biaxial CS in two perpendicular directions (0 to 10%). The morphology of ECs is reported using four parameters; average shape index (SI) and orientation angle (OA) of the cell population as well as the standard deviation (SD) of SI and OA as measures for scattering of cells’ SI and OA from these average values.

Results

A new effective strain ratio (ESR) is defined as the ratio of the undesirable CS to the desirable one. The obtained results of the model, illustrated that the SI and OA of cells increase with absolute value of ESR. In addition, the scattering in the SI of cells decreases with the absolute value of ESR, which means that the cell shapes become more regular. It is shown that the angular irregularity of cells increases at higher ESR values.

Conclusions

The results indicated that, the defined ESR is a stand-alone parameter for describing the realistic mechanical loading on the ECs and their morphological response.

中文翻译：

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响应组合 WSS 和双轴 CS 的内皮细胞形态学：引入有效应变比

介绍

内皮细胞 (ECs) 形态强烈依赖于施加的机械刺激。这些机械刺激包括壁剪切应力 (WSS) 和双轴循环拉伸 (CS)。在组合加载下，CS的效果并不像纯CS那么简单。本研究调查了 ECs 对现实机械刺激的形态反应。

方法

使用我们之前经过验证的模型对细胞群进行了理论上的研究。使用四个参数描述 EC 上的机械刺激；WSS 幅度（0 至 2.0 Pa）、WSS 角度（- 50° 至 50°）和两个垂直方向上的双轴 CS（0 至 10%）。使用四个参数报告 EC 的形态；细胞群的平均形状指数 (SI) 和取向角 (OA) 以及 SI 和 OA 的标准偏差 (SD) 作为测量细胞的 SI 和 OA 从这些平均值散射的量度。

结果

新的有效应变比 (ESR) 定义为不希望的 CS 与理想的 CS 之比。模型得到的结果表明，细胞的SI和OA随着ESR的绝对值的增加而增加。此外，细胞SI中的散射随着ESR的绝对值而减小，这意味着细胞形状变得更加规则。结果表明，在较高的 ESR 值下，细胞的角度不规则性增加。

结论

结果表明，定义的 ESR 是描述 EC 上的实际机械负载及其形态响应的独立参数。