Wang R, Yu X, Gkousioudi A, Zhang Y
Department of Mechanical Engineering, Boston University, Boston, MA 02215.
Department of Biomedical Engineering, Boston University, Boston, MA 02215.
Exp Mech. 2021 Jan;61(1):81-94. doi: 10.1007/s11340-020-00644-y. Epub 2020 Jul 29.
Interlamellar bonding in the arterial wall is often compromised by cardiovascular diseases. However, several recent nationwide and hospital-based studies have uniformly reported reduced risk of thoracic aortic dissection in patients with diabetes. As one of the primary structural constituents in the arterial wall, elastin plays an important role in providing its interlamellar structural integrity.
The purpose of this study is to examine the effects of glycation on the interlamellar bonding properties of arterial elastin.
Purified elastin network was isolated from porcine descending thoracic aorta and incubated in 2 M glucose solution for 7, 14 or 21 days at 37 °C. Peeling and direct tension tests were performed to provide complimentary information on understanding the interlamellar layer separation properties of elastin network with glycation effect. Peeling tests were simulated using a cohesive zone model (CZM). Multiphoton imaging was used to visualize the interlamellar elastin fibers in samples subjected to peeling and direct tension.
Peeling and direct tension tests show that interlamellar energy release rate and strength both increases with the duration of glucose treatment. The traction at damage initiation estimated for the CZM agrees well with the interlamellar strength measurements from direct tension tests. Glycation was also found to increase the interlamellar failure strain of arterial elastin. Multiphoton imaging confirmed the contribution of radially running elastin fibers to resisting dissection.
Nonenzymatic glycation reduces the propensity of arterial elastin to dissection. This study also suggests that the CZM effectively describes the interlamellar bonding properties of arterial elastin.
动脉壁的层间结合常因心血管疾病而受损。然而，最近几项全国性和基于医院的研究均一致报告称，糖尿病患者胸主动脉夹层的风险降低。作为动脉壁的主要结构成分之一，弹性蛋白在提供其层间结构完整性方面发挥着重要作用。
本研究旨在探讨糖基化对动脉弹性蛋白层间结合特性的影响。
从猪降主动脉中分离出纯化的弹性蛋白网络，并在37℃下于2M葡萄糖溶液中孵育7、14或21天。进行剥离试验和直接拉伸试验，以提供补充信息，帮助理解糖基化作用下弹性蛋白网络的层间分离特性。使用内聚区模型（CZM）模拟剥离试验。采用多光子成像技术观察经受剥离和直接拉伸的样品中层间弹性纤维的情况。
剥离试验和直接拉伸试验表明，层间能量释放率和强度均随葡萄糖处理时间的延长而增加。CZM估算的损伤起始时的牵引力与直接拉伸试验测得的层间强度结果吻合良好。还发现糖基化会增加动脉弹性蛋白的层间破坏应变。多光子成像证实了径向排列的弹性纤维对抵抗夹层的作用。
非酶糖基化降低了动脉弹性蛋白发生夹层的倾向。本研究还表明，CZM能有效描述动脉弹性蛋白的层间结合特性。
