Cardiac atrophy after bed rest and spaceflight
Cardiac atrophy after bed rest and spaceflight
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DOI：
10.1152/jappl.2001.91.2.645
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发表时间：
2001-08-01
影响因子：
3.3
通讯作者：
Levine, BD
中科院分区：
文献类型：
--
作者：
Perhonen, MA;Franco, F;Levine, BD
心肌能很好地适应负荷条件的变化。例如，左心室肥厚可能是生理性（通过运动训练）或病理性（通过高血压或瓣膜性心脏病）引起的。如果高血压得到治疗，左室肥厚消退，提示对左室工作敏感。然而，非运动人群的缺乏运动是否会导致左室质量的适应性变化甚至直接萎缩尚不清楚。我们让以前久坐不动的男性进行6周（n = 5）和12周（n = 3）的水平卧床休息。在卧床休息2、6和12周时，采用电影磁共振成像（MRI）测量左室和右室（RV）质量和舒张末期容积；5名健康男性在进行至少6周的日常活动之前和之后作为对照进行了研究。此外，在10天的太空飞行中，四名宇航员被暴露在完全消除流体静力梯度的环境中。在卧床休息期间，6周后左室质量下降了8.0 +/- 2.2% (P = 0.005)，在卧床12周的受试者中，再萎缩7.6 +/- 2.3%；对照组左室质量无变化（153.0 +/- 12.2 g vs. 153.4 +/- 12.1 g, P = 0.81）。卧床休息6周后，平均壁厚下降（4 +/- 2.5%,P = 0.01）与左室质量下降有关，提示与负荷改变有关的生理性重构。左室舒张末期容积在卧床休息2周后下降了14 +/- 1.7% (P = 0.002)，此后变化最小。卧床休息6周后，右心室游离壁质量下降10 +/- 2.7% (P = 0.06)，右心室舒张末期容积下降16 +/- 7.9% （P = 0.06）。经航天飞行后，左室质量下降了12±6.9% （P = 0.07）。总之，心脏萎缩发生在长时间（6周）水平卧床休息期间，也可能发生在短期太空飞行后。我们认为心脏萎缩是由于在真实或模拟微重力条件下对减少心肌负荷和工作的生理适应，并表明心肌在不同负荷条件下的可塑性。
Cardiac muscle adapts well to changes in loading conditions. For example, left ventricular (LV) hypertrophy may be induced physiologically (via exercise training) or pathologically (via hypertension or valvular heart disease). If hypertension is treated, LV hypertrophy regresses, suggesting a sensitivity to LV work. However, whether physical inactivity in nonathletic populations causes adaptive changes in LV mass or even frank atrophy is not clear. We exposed previously sedentary men to 6 (n = 5) and 12 (n = 3) wk of horizontal bed rest. LV and right ventricular (RV) mass and end-diastolic volume were measured using cine magnetic resonance imaging (MRI) at 2, 6, and 12 wk of bed rest; five healthy men were also studied before and after at least 6 wk of routine daily activities as controls. In addition, four astronauts were exposed to the complete elimination of hydrostatic gradients during a spaceflight of 10 days. During bed rest, LV mass decreased by 8.0 +/- 2.2% (P = 0.005) after 6 wk with an additional atrophy of 7.6 +/- 2.3% in the subjects who remained in bed for 12 wk; there was no change in LV mass for the control subjects (153.0 +/- 12.2 vs. 153.4 +/- 12.1 g, P = 0.81). Mean wall thickness decreased (4 +/- 2.5%, P = 0.01) after 6 wk of bed rest associated with the decrease in LV mass, suggesting a physiological remodeling with respect to altered load. LV end-diastolic volume decreased by 14 +/- 1.7% (P = 0.002) after 2 wk of bed rest and changed minimally thereafter. After 6 wk of bed rest, RV free wall mass decreased by 10 +/- 2.7% (P = 0.06) and RV end-diastolic volume by 16 +/- 7.9% (P = 0.06). After spaceflight, LV mass decreased by 12 +/- 6.9% (P = 0.07). In conclusion, cardiac atrophy occurs during prolonged (6 wk) horizontal bed rest and may also occur after short-term spaceflight. We suggest that cardiac atrophy is due to a physiological adaptation to reduced myocardial load and work in real or simulated microgravity and demonstrates the plasticity of cardiac muscle under different loading conditions.