Department of Aeronautics, Imperial College London, UK.
Ann Biomed Eng. 2010 Sep;38(9):2805-16. doi: 10.1007/s10439-010-0039-x.
A computational model of Nitric Oxide (NO) production and transport within a parallel-plate flow chamber coated with endothelial cells is presented. The relationship between NO concentration and Wall Shear Stress (WSS) at the endothelium is investigated in detail. An increase in WSS is associated with two phenomena: enhanced NO production by the endothelial cells, and an increase in the velocity at which NO is convected out of the chamber. These two phenomena have opposite effects on endothelial NO concentration. In physiologically realistic cases, the balance between them is found to vary as WSS is raised, resulting in a complex non-monotonic dependence of endothelial NO concentration on WSS. Also, it is found that a NO concentration boundary layer develops within the chamber, leading to substantial spatial variations in NO concentration along the length of the device. Finally, the implications of a negative feedback mechanism (that affects NO production) are presented. The results emphasize the role of convection on NO transport within flow chambers, which has been overlooked or misinterpreted in most previous theoretical studies. It is hoped that the conclusions of this study can be used to aid accurate interpretation of related experimental data.
本文提出了一种在覆有内皮细胞的平行板流室中模拟一氧化氮（NO）产生和传输的计算模型。详细研究了 NO 浓度与内皮壁面切应力（WSS）之间的关系。壁面切应力的增加与两种现象有关：内皮细胞中 NO 产生的增强，以及 NO 被逐出腔室的速度的增加。这两种现象对内皮细胞中 NO 浓度有相反的影响。在生理上合理的情况下，发现它们之间的平衡随着壁面切应力的升高而变化，导致内皮细胞中 NO 浓度与壁面切应力之间存在复杂的非单调关系。此外，还发现腔室内形成了一个 NO 浓度边界层，导致 NO 浓度在装置长度方向上存在显著的空间变化。最后，提出了一个负反馈机制（影响 NO 产生）的影响。研究结果强调了对流在流室内 NO 传输中的作用，这在大多数先前的理论研究中被忽视或误解。希望本研究的结论能够用于辅助对相关实验数据的准确解释。
