Memorial Sloan Kettering Cancer Center, New York, NY.
KBRWyle, Houston, TX.
Med Sci Sports Exerc. 2018 Sep;50(9):1940-1949. doi: 10.1249/MSS.0000000000001619.
Early and consistent evaluation of cardiac morphology and function throughout an atrophic stimulus is critically important for the design and optimization of interventions. This randomized controlled trial was designed 1) to characterize the time course of unloading-induced morphofunctional remodeling and 2) to examine the effects of exercise with and without low-dose testosterone supplementation on cardiac biomarker, structural, and functional parameters during unloading.
Twenty-six subjects completed 70 d of head-down tilt bed rest (BR): 9 were randomized to exercise training (Ex), 8 to EX and low-dose testosterone (ExT), and 9 remained sedentary (CONT). Exercise consisted of high-intensity, continuous, and resistance exercise. Cardiac morphology (left ventricular mass [LVM]) and mechanics (longitudinal, radial, and circumferential strain and twist), cardiovascular biomarkers, and cardiorespiratory fitness (V˙O2peak) were assessed before, during, and after BR.
Sedentary BR resulted in a progressive decline in LVM, longitudinal, radial, and circumferential strain in CONT, whereas Ex and ExT mitigated decreases in LVM and function. Twist was increased throughout BR in sedentary BR, whereas after an initial increase at BR7, there were no further changes in twist in Ex and ExT. HDL cholesterol was significantly decreased in all groups compared with pre-BR (P < 0.007). There were no significant changes in other cardiovascular biomarkers. Change in twist was significantly related to change in V˙O2max (R = 0.68, P < 0.01).
An integrated approach with evaluation of cardiac morphology, mechanics, V˙O2peak, and biomarkers provides extensive phenotyping of cardiovascular atrophic remodeling. Exercise training and exercise training with low-dose testosterone supplementation abrogates atrophic remodeling.
在萎缩刺激过程中早期且持续评估心脏形态和功能对于干预措施的设计和优化至关重要。本随机对照试验旨在：1）描述去负荷诱导的形态功能重构的时程；2）研究运动及运动联合低剂量睾酮补充对去负荷期间心脏生物标志物、结构和功能参数的影响。
26 名受试者完成了 70 天的头低位卧床（BR）：9 名随机分配到运动训练（Ex）组，8 名分配到 Ex 和低剂量睾酮（ExT）组，9 名保持安静（CONT）。运动包括高强度、连续和阻力运动。在 BR 前、期间和之后评估心脏形态（左心室质量[LVM]）和力学（纵向、径向和周向应变和扭转）、心血管生物标志物和心肺功能（V˙O2peak）。
BR 期间，安静 BR 导致 LVM、纵向、径向和周向应变呈进行性下降，而 Ex 和 ExT 减轻了 LVM 和功能的下降。在安静 BR 中，扭转在整个 BR 期间增加，而在 BR7 时出现初始增加后，Ex 和 ExT 中的扭转没有进一步变化。与 BR 前相比，所有组的高密度脂蛋白胆固醇均显著降低（P < 0.007）。其他心血管生物标志物没有显著变化。扭转的变化与 V˙O2max 的变化显著相关（R = 0.68，P < 0.01）。
采用心脏形态、力学、V˙O2peak 和生物标志物评估的综合方法为心血管萎缩重构提供了广泛的表型分析。运动训练和运动联合低剂量睾酮补充可阻断萎缩性重构。
