VanBavel Ed, Tuna Bilge Guvenc
Department of Biomedical Engineering and Physics, Academic Medical Center, Amsterdam, The Netherlands.
PLoS One. 2014 Jan 31;9(1):e86901. doi: 10.1371/journal.pone.0086901. eCollection 2014.
Organ perfusion is regulated by vasoactivity and structural adaptation of small arteries and arterioles. These resistance vessels are sensitive to pressure, flow and a range of vasoactive stimuli. Several strongly interacting control loops exist. As an example, the myogenic response to a change of pressure influences the endothelial shear stress, thereby altering the contribution of shear-dependent dilation to the vascular tone. In addition, acute responses change the stimulus for structural adaptation and vice versa. Such control loops are able to maintain resistance vessels in a functional and stable state, characterized by regulated wall stress, shear stress, matched active and passive biomechanics and presence of vascular reserve. In this modeling study, four adaptation processes are identified that together with biomechanical properties effectuate such integrated regulation: control of tone, smooth muscle cell length adaptation, eutrophic matrix rearrangement and trophic responses. Their combined action maintains arteries in their optimal state, ready to cope with new challenges, allowing continuous long-term vasoregulation. The exclusion of any of these processes results in a poorly regulated state and in some cases instability of vascular structure.
器官灌注受小动脉和微动脉的血管活性及结构适应性调节。这些阻力血管对压力、血流及一系列血管活性刺激敏感。存在多个相互作用强烈的控制回路。例如，对压力变化的肌源性反应会影响内皮剪切应力，从而改变剪切依赖性舒张对血管张力的贡献。此外，急性反应会改变结构适应性的刺激因素，反之亦然。此类控制回路能够使阻力血管维持在功能稳定状态，其特征为调节壁应力、剪切应力、匹配的主动和被动生物力学以及存在血管储备。在本建模研究中，确定了四个与生物力学特性共同实现这种综合调节的适应过程：张力控制、平滑肌细胞长度适应、富养基质重排和营养反应。它们的联合作用使动脉维持在最佳状态，随时准备应对新挑战，实现持续的长期血管调节。排除这些过程中的任何一个都会导致调节不良状态，在某些情况下还会导致血管结构不稳定。
