Institute of Cardiovascular Sciences, St. Boniface Hospital Research Centre and Department of Physiology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada.
J Card Fail. 2010 May;16(5):439-49. doi: 10.1016/j.cardfail.2009.12.017. Epub 2010 Feb 11.
This study examined the sex differences for hemodynamic and echocardiographic changes in hypertrophied and failing hearts induced by arteriovenous (AV) shunt.
Echocardiographic and hemodynamic alterations were determined in male and female rats at 4 and 16 weeks after AV shunt. Ovariectomized females treated with estrogen for 16 weeks post-AV shunt were also used. Both genders developed cardiac hypertrophy at 4 and 16 weeks post-AV shunt; however, the increase in cardiac muscle mass was greater in females than males at 16 weeks. At 4 weeks post-AV shunt, increases in ventricular dimensions and left ventricular end-diastolic pressure (LVEDP) as well as a decrease in fractional shortening occurred in males only. Unlike the females, the rates of pressure development (+dP/dt) and decay (-dP/dt) were depressed and LVEDP increased in male rats at 16 weeks post-AV shunt. An increase in cardiac output was seen in both genders, but this was more marked in the males at 4 and 16 weeks post-AV shunt. Although mRNA levels for ACE were increased in both male and female rats at 4 and 16 weeks, mRNA levels for angiotensin II type 1 receptor were increased in males at 16 weeks only. Furthermore, increases in plasma catecholamines were elevated in males but were decreased or unchanged in females at 16 weeks of AV shunt. LV internal diameters as well as depressed fractional shortening occurred in males whereas increases in posterior wall thickness were seen in the female rats at 16 weeks of AV shunt. Ovariectomy resulted in depressed +dP/dt, -dP/dt, and fractional shortening, whereas a marked increase in cardiac output as well as increased LVEDP and LV internal diameters were observed at 16 weeks post-AV shunt. Although treatment with 17-beta estradiol normalized +/-dP/dt, LVEDP remained elevated.
Gender differences in cardiac function may be due to differences in the type of cardiac remodeling as a consequence of AV shunt. Furthermore, estrogen appears to play an important role in preventing cardiac dysfunction and adverse ventricular remodeling in female rats.
本研究旨在探讨动静脉（AV）分流引起的肥大和衰竭心脏的血流动力学和超声心动图变化的性别差异。
在 AV 分流后 4 周和 16 周时，测定雄性和雌性大鼠的超声心动图和血流动力学改变。还使用了在 AV 分流后 16 周接受雌激素治疗的去卵巢雌性大鼠。两种性别在 AV 分流后 4 周和 16 周均出现心肌肥厚；然而，16 周时女性心肌质量的增加大于男性。在 AV 分流后 4 周，仅雄性出现心室腔增大和左心室舒张末期压（LVEDP）升高以及短轴缩短率降低。与女性不同，雄性大鼠在 AV 分流后 16 周时，压力发展速度（+dP/dt）和衰减速度（-dP/dt）降低，LVEDP 升高。两种性别均出现心输出量增加，但在 AV 分流后 4 周和 16 周时，雄性更为明显。尽管在 AV 分流后 4 周和 16 周时雄性和雌性大鼠的 ACE mRNA 水平均升高，但仅在雄性大鼠中，血管紧张素 II 型 1 受体的 mRNA 水平升高。此外，在 AV 分流 16 周时，雄性大鼠的血浆儿茶酚胺水平升高，但雌性大鼠的儿茶酚胺水平降低或不变。AV 分流 16 周时，雄性大鼠出现左心室内径增大和短轴缩短率降低，而雌性大鼠出现后室壁厚度增加。去卵巢导致+dP/dt、-dP/dt 和短轴缩短率降低，但在 AV 分流后 16 周时，心输出量明显增加，LVEDP 和左心室内径升高。虽然用 17-β雌二醇治疗使 +/-dP/dt 正常化，但 LVEDP 仍升高。
心脏功能的性别差异可能是由于 AV 分流引起的心脏重塑类型不同所致。此外，雌激素似乎在预防雌性大鼠的心脏功能障碍和不良心室重塑中发挥重要作用。
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