Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.
Department of Obstetrics and Gynaecology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
Am J Physiol Heart Circ Physiol. 2022 Jul 1;323(1):H72-H88. doi: 10.1152/ajpheart.00693.2021. Epub 2022 Apr 22.
`The entire maternal circulation adapts to pregnancy, and this adaption is particularly extensive in the uterine circulation where the major vessels double in size to facilitate an approximately 15-fold increase in blood supply to this organ over the course of pregnancy. Several factors may play a role in both the remodeling and biomechanical function of the uterine vasculature including the paracrine microenvironment, passive properties of the vessel wall, and active components of vascular function (incorporating the myogenic response and response to shear stress induced by intravascular blood flow). However, the interplay between these factors and how this plays out in an organ-specific manner to induce the extent of remodeling observed in the uterus is not well understood. Here we present an integrated assessment of the uterine radial arteries, likely rate limiters to the flow of oxygenated maternal blood to the placental surface, via computational modeling and pressure myography. We show that uterine radial arteries behave differently to other systemic vessels (higher compliance and shear-mediated constriction) and that their properties change with the adaptation to pregnancy (higher myogenic tone, higher compliance, and ability to tolerate higher flow rates before constricting). Together, this provides a useful tool to improve our understanding of the role of uterine vascular adaptation in normal and abnormal pregnancies and highlights the need for vascular bed-specific investigations of vascular function in health and disease. To our knowledge, this is the first data-driven computational model of autoregulation of uterine radial arteries, likely rate limiters of maternal blood flow to the placenta. The study demonstrates that uterine radial arteries behave differently from systemic vessels (higher compliance, shear-mediated constriction) and change in pregnancy (higher myogenic tone, higher compliance, tolerance of higher flow rates). This pregnancy-specific mathematical model of vascular reactivity allows interrogation of the functional significance of incomplete vascular adaption in pathology.
整个母体循环适应妊娠，而子宫循环的适应特别广泛，主要血管直径增加一倍，以便在妊娠过程中为该器官提供大约 15 倍的血液供应增加。包括旁分泌微环境、血管壁的被动特性和血管功能的主动成分（包括肌源性反应和对血管内血流引起的切应力的反应）在内的几个因素可能在子宫血管重塑和生物力学功能中发挥作用。然而，这些因素之间的相互作用以及它们如何以器官特异性的方式发挥作用，以诱导在子宫中观察到的重塑程度尚不清楚。在这里，我们通过计算建模和压力描记术对子宫放射状动脉进行了综合评估，这可能是限制含氧母体血液流向胎盘表面的流量的限制因素。我们表明，子宫放射状动脉的行为与其他系统性血管不同（顺应性更高，剪切介导的收缩），并且它们的特性随着妊娠适应而改变（更高的肌源性张力、更高的顺应性和能够耐受更高的血流速度而不会收缩）。总之，这为我们提供了一种有用的工具，可提高我们对正常和异常妊娠中子宫血管适应作用的理解，并强调了在健康和疾病中对血管功能进行特定于血管床的研究的必要性。据我们所知，这是第一个关于子宫放射状动脉自动调节的基于数据的计算模型，可能是母体血液流向胎盘的限制因素。该研究表明，子宫放射状动脉的行为与系统性血管不同（顺应性更高，剪切介导的收缩），并在妊娠期间发生变化（肌源性张力更高，顺应性更高，能够耐受更高的血流速度）。这种妊娠特异性血管反应性数学模型允许对病理中不完全血管适应的功能意义进行探究。
