Palombo Carlo, Morizzo Carmela, Baluci Martino, Lucini Daniela, Ricci Stefano, Biolo Gianni, Tortoli Piero, Kozakova Michaela
Department of Surgical, Medical, Molecular and Critical Area Pathology, University of Pisa, 56124 Pisa, Italy.
Department of Medical Biotechnologies and Translational Medicine, University of Milan, 20129 Milan, Italy.
Biomed Res Int. 2015;2015:342565. doi: 10.1155/2015/342565. Epub 2015 Jan 13.
The effects of simulated microgravity on the static and dynamic properties of large arteries are still mostly unknown. The present study evaluated, using an integrated vascular approach, changes in structure and function of the common carotid and femoral arteries (CCA and CFA) after prolonged head-down tilt bed rest (HDTBR). Ten healthy men were enrolled in a 5-week HDTBR study endorsed by the Italian Space Agency (ASI). Arterial geometry, flow, stiffness, and shear rate were evaluated by ultrasound. Local carotid pulse pressure and wave reflection were studied by applanation tonometry. After five weeks of HDTBR, CFA showed a decrease in lumen diameter without significant changes in wall thickness (IMT), resulting in an inward remodeling. Local carotid pulse pressure decreased and carotid-to-brachial pressure amplification increased. The ratio of systolic-to-diastolic volumetric flow in CFA decreased, whereas in CCA it tended to increase. Indices of arterial stiffness and shear rate did not change during HDTBR, either in CCA or CFA. In summary, prolonged HDTBR has a different impact on CCA and CFA structure and flow, probably depending on the characteristics of the vascular bed perfused.
模拟微重力对大动脉静态和动态特性的影响大多仍不清楚。本研究采用综合血管方法，评估了长时间头低位卧床休息（HDTBR）后颈总动脉和股动脉（CCA和CFA）的结构和功能变化。十名健康男性参与了一项由意大利航天局（ASI）批准的为期5周的HDTBR研究。通过超声评估动脉几何形状、血流、硬度和剪切率。通过压平式眼压计研究局部颈动脉脉搏压和波反射。HDTBR五周后，CFA的管腔直径减小，而壁厚（IMT）无显著变化，导致向内重塑。局部颈动脉脉搏压降低，颈动脉与肱动脉压力放大率增加。CFA中收缩期与舒张期容积血流比降低，而CCA中则趋于增加。HDTBR期间，CCA和CFA的动脉硬度和剪切率指标均未改变。总之，长时间HDTBR对CCA和CFA的结构和血流有不同影响，可能取决于所灌注血管床的特征。
