Localised micro-mechanical stiffening in the ageing aorta
Localised micro-mechanical stiffening in the ageing aorta
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DOI：
10.1016/j.mad.2011.07.003
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发表时间：
2011-10-01
影响因子：
5.3
通讯作者：
Sherratt, Michael J.
中科院分区：
文献类型：
--
作者：
Graham, Helen K.;Akhtar, Riaz;Sherratt, Michael J.
与年龄相关的组织弹性丧失是人类发病的常见原因，动脉硬化（血管硬化）与致命性中风和心力衰竭的发展有关。然而，在缺乏适当的微观力学测试方法的情况下，多种结构重塑事件被认为是动脉硬化的原因。因此，利用雌性羊主动脉（年轻：8岁）的衰老模型，我们：(i)量化了与年龄相关的宏观机械刚度，（ii）原位定位了声波速度的微米级变化（一种测量组织刚度的方法），（iii）表征了胶原蛋白和弹性纤维的重塑。随着年龄的增长，宏观力学刚度和平均微观波速都有所增加(因此刚度；年轻波速：1701 +/- 1 m s(-1)，老年波速：1710 +/- 1 m s(-1), p < 0.001)，这些波速位于大弹性片层之间富含胶原原纤维的区域。这些微观力学变化与胶原蛋白和弹性纤维含量的增加有关（胶原蛋白组织面积，年轻：31 +/- 2%，年老：40 +/- 4%，p < 0.05；弹性纤维组织面积，年轻：55 +/- 3%，年老：69 +/- 4%，p < 0.001）。因此，局部胶原纤维化可能在介导与年龄相关的动脉硬化中起关键作用。此外，高频扫描声学显微镜能够共同定位老化组织的微观力学和微观结构变化。2011爱思唯尔爱尔兰有限公司版权所有。
Age-related loss of tissue elasticity is a common cause of human morbidity and arteriosclerosis (vascular stiffening) is associated with the development of both fatal strokes and heart failure. However, in the absence of appropriate micro-mechanical testing methodologies, multiple structural remodelling events have been proposed as the cause of arteriosclerosis. Therefore, using a model of ageing in female sheep aorta (young: 8 years) we: (i) quantified age-related macro-mechanical stiffness, (ii) localised in situ micro-metre scale changes in acoustic wave speed (a measure of tissue stiffness) and (iii) characterised collagen and elastic fibre remodelling. With age, there was an increase in both macro-mechanical stiffness and mean microscopic wave speed (and hence stiffness; young wave speed: 1701 +/- 1 m s(-1), old wave speed: 1710 +/- 1 m s(-1), p < 0.001) which was localized to collagen fibril-rich regions located between large elastic lamellae. These micro-mechanical changes were associated with increases in both collagen and elastic fibre content (collagen tissue area, young: 31 +/- 2%, old: 40 +/- 4%, p < 0.05; elastic fibre tissue area, young: 55 +/- 3%, old: 69 +/- 4%, p < 0.001). Localised collagen fibrosis may therefore play a key role in mediating age-related arteriosclerosis. Furthermore, high frequency scanning acoustic microscopy is capable of co-localising micro-mechanical and micro-structural changes in ageing tissues. (C) 2011 Elsevier Ireland Ltd. All rights reserved.