Modelling capillary oxygen supply capacity in mixed muscles: Capillary domains revisited
Modelling capillary oxygen supply capacity in mixed muscles: Capillary domains revisited
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DOI：
10.1016/j.jtbi.2014.04.016
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发表时间：
2014-09-07
影响因子：
2
通讯作者：
Egginton, Stuart
中科院分区：
文献类型：
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作者：
Al-Shammari, Abdullah A.;Gaffney, Eamonn A.;Egginton, Stuart
针对与肌肉纤维的异常氧气运输相关的病理情况，开发有效的治疗干预措施至关重要地取决于毛细血管的客观特征。局部毛细血管供应指数有可能识别细小组织病理和调节失调的发生。通过考虑平面毛细血管位置产生的Voronoi多边形(VP)的分布作为毛细血管供应区的代表，将详细的组织几何形状，如肌肉纤维大小，纳入到这些测量中。此前，详细的模拟已经预测，对于摄氧量均匀的肌肉组织来说，这通常是准确的。在这里，我们将这个模型框架扩展到异种肌肉，以评估在最大可持续耗氧量下的毛细血管供应能力。我们证明，对于具有异质纤维特性的肌肉，VP理论上提供了一种计算上简单但往往准确的陷阱区域(TR)表示，这些区域是从生物物理传输模型中预测的，以表示由单个毛细血管供应的组织区域。然而，在大纤维周围，以及在氧化能力大不相同的纤维的界面上，VP的这种使用可能变得不那么准确。在这种情况下，tr可以提供更稳健的毛细血管供应区的表示。此外，鉴于Vp只能近似地通过毛细血管输送氧气，我们表明它们与TR的一般密切关系表明：(1)纤维类型分布可能受到严格调控，以避免具有高氧化能力的大纤维；(2)解剖纤维分布也受到严格调控，以防止代谢上不同的纤维之间存在较大的表面积相互作用；以及(3)在慢性缺氧组织中，毛细血管分布在决定氧气供应方面比纤维需求的空间异质性更重要。(C)2014爱思唯尔有限公司。保留所有权利。
Developing effective therapeutic interventions for pathological conditions associated with abnormal oxygen transport to muscle fibres critically depends on the objective characterisation of capillarity. Local indices of capillary supply have the potential to identify the onset of fine-scale tissue pathologies and dysregulation. Detailed tissue geometry, such as muscle fibre size, has been incorporated into such measures by considering the distribution of Voronoi polygons (VP) generated from planar capillary locations as a representation of capillary supply regions. Previously, detailed simulations have predicted that this is generally accurate for muscle tissue with uniform oxygen uptake. Here we extend this modelling framework to heterogeneous muscle for the assessment of capillary supply capacity under maximal sustainable oxygen consumption. We demonstrate for muscle with heterogeneous fibre properties that VP theoretically provide a computationally simple but often accurate representation of trapping regions (TR), which are predicted from biophysical transport models to represent the areas of tissue supplied by individual capillaries. However, this use of VP may become less accurate around large fibres, and at the interface of fibres of largely different oxidative capacities. In such cases, TR may provide a more robust representation of capillary supply regions. Additionally, given VP can only approximate oxygen delivery by capillaries, we show that their generally close relationship to TR suggests that (1) fibre type distribution may be tightly regulated to avoid large fibres with high oxidative capacities, (2) the anatomical fibre distribution is also tightly regulated to prevent a large surface area of interaction between metabolically dissimilar fibres, and (3) in chronically hypoxic tissues capillary distribution is more important in determining oxygen supply than the spatial heterogeneity of fibre demand. (C) 2014 Elsevier Ltd. All rights reserved.