通过多尺度建模在长期航天飞行期间心血管失调
Cardiovascular deconditioning during long-term spaceflight through multiscale modeling
摘要：
几个世纪以来，载人航天一直令人着迷，代表着探索未知、挑战新领域、推进技术和进一步推动科学边界的无形需求。一个重要的关键领域是心血管失调，即由于持续处于微重力状态而引起的血液动力学变化-从血容量的变化和减少到心脏功能的改变。从生理学的角度看，准确把握0 G调整点本身是非常重要的，也是保证航天员长期飞行安全和体能的基础。然而，迄今为止，心血管去适应的血流动力学细节是不完整的，不一致的，测量不好的;因此，计算方法是非常有价值的。我们提出了一个经过验证的1D-0 D多尺度模型，以研究与1G仰卧参考条件相比，长期0 G太空飞行的心血管反应。心脏功、耗氧量和收缩力指数以及中心平均压和脉压降低，增加了心脏失调情况。研究发现，航天旅行者的运动耐受力与久坐不动的未经训练的人相当。在毛细血管-静脉水平，观察到显著的波形改变，这可以在细胞水平上改变常规灌注和平均营养供应。目前的研究表明，应特别注意未来的长途航天飞行，这些飞行在恢复部分重力时需要迅速的体力（例如，月球/火星登陆）。由于空间飞行条件失调具有与加速衰老相似的特征，因此，理解微重力条件失调机制也与理解地球上的衰老生理学有关。
英文摘要：
Human spaceflight has been fascinating man for centuries, representing the intangible need to explore the unknown, challenge new frontiers, advance technology and push scientific boundaries further. A key area of importance is cardiovascular deconditioning, that is, the collection of hemodynamic changes - from blood volume shift and reduction to altered cardiac function - induced by sustained presence in microgravity. A thorough grasp of the 0G adjustment point per se is important from a physiological viewpoint and fundamental for astronauts' safety and physical capability on long spaceflights. However, hemodynamic details of cardiovascular deconditioning are incomplete, inconsistent and poorly measured to date; thus a computational approach can be quite valuable. We present a validated 1D-0D multiscale model to study the cardiovascular response to long-term 0G spaceflight in comparison to the 1G supine reference condition. Cardiac work, oxygen consumption and contractility indexes, as well as central mean and pulse pressures were reduced, augmenting the cardiac deconditioning scenario. Exercise tolerance of a spaceflight traveler was found to be comparable to an untrained person with a sedentary lifestyle. At the capillary-venous level significant waveform alterations were observed which can modify the regular perfusion and average nutrient supply at the cellular level. The present study suggests special attention should be paid to future long spaceflights which demand prompt physical capacity at the time of restoration of partial gravity (e.g., Moon/Mars landing). Since spaceflight deconditioning has features similar to accelerated aging understanding deconditioning mechanisms in microgravity are also relevant to the understanding of aging physiology on Earth.
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