Effect of age on myocardial adaptation to volume overload in the rat.
Effect of age on myocardial adaptation to volume overload in the rat.
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年龄对大鼠心肌容量超负荷适应的影响。
DOI：
10.1172/jci113530
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
Wei,JY
中科院分区：
文献类型：
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作者：
Isoyama,S;Grossman,W;Wei,JY
为了验证左心室（LV）适应容量过载的能力可能随着年龄的增长而下降的假设，我们检查了年轻成年（9个月）和老年（18或22个月）Fischer大鼠主动脉功能不全时的血流动力学和心肌肥厚程度。在主动脉功能不全之前、之后、2周和4周，使用导管技术测量左室和主动脉压。术后4周测量主动脉流量，估计左室被动压力-容积关系及左室死亡后肥厚程度。手术造成主动脉不全后，年轻大鼠和年老大鼠的左室舒张末压升高相似（年轻大鼠从4.8 +/- 0.6上升到12.0 +/- 1.5 mmHg, P < 0.01；年老大鼠从4.9 +/- 0.4上升到11.0 +/- 0.7 mmHg, P < 0.01）。幼龄大鼠左室舒张末期压在第2周和第4周分别降至8.0 +/- 1.0和8.5 +/- 0.9 mmHg （P < 0.05）。相比之下，老年大鼠在第2周（16.9 +/- 3.1 mmHg）和第4周（16.1 +/- 2.7 mmHg）时的左室舒张末压甚至高于主动脉不全后立即测量的值。在第4周，老龄大鼠左室舒张末期经壁应力（由体内左室舒张末期压计算，以及杀死后获得的压力-体积关系和肌肉质量）高于幼鼠。幼龄大鼠4周时舒张压-容积关系右移（P < 0.01），左室干重、左室干重/胫骨长、左室心肌蛋白含量分别增加26% （P < 0.01）、24% （P < 0.01）、33% （P < 0.01）。然而，主动脉功能不全的老龄大鼠在4周时的压力-容积关系、干重或蛋白质含量没有明显变化。这些结果表明，高龄降低了响应容量过载的左室肥厚能力，老年大鼠的左室肥厚反应降低导致左室舒张末期压和壁应力持续升高。
To test the hypothesis that the capacity for left ventricular (LV) adaptation to volume overload might diminish with age, we examined the hemodynamics and degree of myocardial hypertrophy in response to aortic insufficiency in young adult (9 mo) and old (18 or 22 mo) Fischer rats. Before, immediately after, and at 2 and 4 wk after creating aortic insufficiency, LV and aortic pressures were measured using a catheterization technique. 4 wk after surgery, we measured aortic flow, and estimated the LV passive pressure-volume relationship and the degree of LV hypertrophy after killing. Immediately after the surgical creation of aortic insufficiency, both young and old rats showed similar elevation of LV end-diastolic pressure (from 4.8 +/- 0.6 to 12.0 +/- 1.5 mmHg in the young rats, P less than 0.01; from 4.9 +/- 0.4 to 11.0 +/- 0.7 mmHg in the old rats, P less than 0.01). In the young rats LV, end-diastolic pressure decreased to 8.0 +/- 1.0 and to 8.5 +/- 0.9 mmHg at 2 and 4 wk (P less than 0.05). In contrast, LV end-diastolic pressure at 2 (16.9 +/- 3.1 mmHg) and 4 wk (16.1 +/- 2.7 mmHg) in the old rats was even higher, compared with the values measured immediately after aortic insufficiency. At 4 wk, LV end-diastolic meridional wall stress (calculated from the in vivo LV end-diastolic pressure, and the pressure-volume relationship and muscle mass obtained after killing) was higher in the old rats than in the young rats. In the young rats, the diastolic pressure-volume relationship at 4 wk shifted to the right (P less than 0.01), and LV dry weight, LV dry weight/tibial length, and protein content of the LV myocardium increased by 26% (P less than 0.01), 24% (P less than 0.01), and 33% (P less than 0.01), respectively. However, old rats with aortic insufficiency did not show a significant change in the pressure-volume relationship, dry weight, or protein content at 4 wk. These results suggest that advanced age diminishes the capacity for LV hypertrophy in response to a volume overload, and this reduced LV hypertrophic response in the old rats resulted in persistent elevation of LV end-diastolic pressure and wall stress.