Aquila Louise A, McCarthy Patrick M, Smedira Nicholas G, Young James B, Moravec Christine Schomisch
Kaufman Center for Heart Failure, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA.
J Heart Lung Transplant. 2004 Aug;23(8):954-63. doi: 10.1016/j.healun.2004.05.018.
Mechanical support of the failing human heart with a left ventricular assist device (LVAD) normalizes many components of myocyte structure and function. We hypothesized that recovery of the cytoskeleton, a major site of mechanotransduction in cardiac myocytes, is crucial for sustained improvement of myocardial function. We therefore measured the effects of LVAD support on 4 cytoskeletal proteins in single human heart cells.
Myocytes were isolated from non-failing (NF), hypertrophied (H), failing (F) and LVAD-supported failing (L) human hearts. Protein quantitation was performed using Western blot analysis and cellular distribution was determined by immunolabeling and confocal microscopy.
alpha-actinin did not differ in cells from H or F as compared with NF, and L had no effect. Vinculin was not quantitatively different in H or F vs NF, but localization at the intercalated disks was significantly decreased in H and absent in F, and this pattern was consistently reversed in L. Desmin protein was significantly increased in F vs NF, both in quantity and distribution, and these increases were reversed in L. beta-tubulin was increasingly polymerized in H and F, and the hyperpolymerization was reversed in L.
On the level of the single cardiomyocyte, major proteins of the cytoskeleton are significantly altered in hypertrophied and failing human hearts. These alterations are reversed by mechanical unloading with an LVAD, suggesting that the cytoskeleton is not the limiting factor in determining full cardiac recovery.
使用左心室辅助装置（LVAD）对衰竭的人体心脏进行机械支持可使心肌细胞结构和功能的许多成分恢复正常。我们假设细胞骨架的恢复是心肌细胞机械转导的主要部位，对心肌功能的持续改善至关重要。因此，我们测量了LVAD支持对单个人类心脏细胞中4种细胞骨架蛋白的影响。
从非衰竭（NF）、肥厚（H）、衰竭（F）和LVAD支持的衰竭（L）人类心脏中分离心肌细胞。使用蛋白质印迹分析进行蛋白质定量，并通过免疫标记和共聚焦显微镜确定细胞分布。
与NF相比，H或F细胞中的α-肌动蛋白没有差异，L也没有影响。与NF相比，H或F中的纽蛋白在数量上没有差异，但在H中闰盘处的定位显著减少，在F中不存在，而在L中这种模式始终相反。结蛋白在F中与NF相比，在数量和分布上均显著增加，而在L中这些增加被逆转。β-微管蛋白在H和F中逐渐聚合，而在L中这种超聚合被逆转。
在单个心肌细胞水平上，肥厚和衰竭的人类心脏中细胞骨架的主要蛋白质发生了显著改变。这些改变通过LVAD的机械卸载得以逆转，表明细胞骨架不是决定心脏完全恢复的限制因素。
