Modeling oxygen transport in human placental terminal villi
Modeling oxygen transport in human placental terminal villi
复制标题
DOI：
10.1016/j.jtbi.2011.09.008
复制
发表时间：
2011-12-21
影响因子：
2
通讯作者：
Vvedensky, D. D.
中科院分区：
文献类型：
--
作者：
Gill, J. S.;Salafia, C. M.;Vvedensky, D. D.
将氧气从母体血液输送到胎儿血液是胎盘的主要功能。量化这种交换的有效性仍然是识别健康胎盘的关键，因为绒毛内的毛细血管数量、口径和位置存在很大差异，即使是临床上认为“正常”的胎盘也是如此。通过考虑绒毛膜到毛细血管膜的传输，可以在数字显微照片所代表的终末绒毛中对静态氧扩散进行数值求解。我们的目标是提供一种方法来确定扩散筛查是否可以在胎盘绒毛中发挥作用以及在多大程度上发挥作用。2002 年北卡罗来纳州妊娠、感染和营养研究中的终末绒毛分段数码显微照片被用作求解稳态扩散方程的几何基础。假设母体静脉氧浓度恒定且胎儿毛细血管膜吸收完美。系统效率定义为进入绒毛的氧气通量与其中包含的毛细管面积之和的比率。通过比较数值和理论最大氧通量来量化扩散筛选。绒毛氧运输效率的各种测量与绒毛内毛细血管的数量之间建立了密切的联系。扩散筛选的强度还与绒毛内毛细血管的数量有关。我们对扩散效率的测量结果表明，随着每个绒毛毛细血管数量的变化，扩散效率会降低。这种低效率、高毛细管数关系支持我们的假设，即该系统中存在扩散筛选。当多个毛细血管竞争扩散氧气时，每个毛细血管的氧气输送会减少。可以获得氧通量、毛细血管和绒毛区域的完整图像，并为未来的工作提供了机会。 (C) 2011 Elsevier Ltd. 保留所有权利。
Oxygen transport from maternal blood to fetal blood is a primary function of the placenta. Quantifying the effectiveness of this exchange remains key in identifying healthy placentas because of the great variability in capillary number, caliber and position within the villus-even in placentas deemed clinically "normal". By considering villous membrane to capillary membrane transport, stationary oxygen diffusion can be numerically solved in terminal villi represented by digital photomicrographs. We aim to provide a method to determine whether and if so to what extent diffusional screening may operate in placental villi.Segmented digital photomicrographs of terminal villi from the Pregnancy, Infection and Nutrition study in North Carolina 2002 are used as a geometric basis for solving the stationary diffusion equation. Constant maternal vinous oxygen concentration and perfect fetal capillary membrane absorption are assumed. System efficiency is defined as the ratio of oxygen flux into a villus and the sum of the capillary areas contained within. Diffusion screening is quantified by comparing numerical and theoretical maximum oxygen fluxes.A strong link between various measures of villous oxygen transport efficiency and the number of capillaries within a villus is established. The strength of diffusional screening is also related to the number of capillaries within a villus.Our measures of diffusional efficiency are shown to decrease as a function of the number of capillaries per villus. This low efficiency, high capillary number relationship supports our hypothesis that diffusional screening is present in this system. Oxygen transport per capillary is reduced when multiple capillaries compete for diffusing oxygen. A complete picture of oxygen fluxes, capillary and villus areas is obtainable and presents an opportunity for future work. (C) 2011 Elsevier Ltd. All rights reserved.