Department of Vascular and Endovascular Surgery, Klinikum rechts der Isar, Technische Universität München, Germany.
Mechanics & High Performance Computing Group, Technische Universität München, Germany.
Eur J Vasc Endovasc Surg. 2015 Aug;50(2):167-74. doi: 10.1016/j.ejvs.2015.03.021. Epub 2015 Apr 16.
Little is known about the interactions between extracellular matrix (ECM) proteins and locally acting mechanical conditions and material macroscopic properties in abdominal aortic aneurysm (AAA). In this study, ECM components were investigated with correlation to corresponding biomechanical properties and loads in aneurysmal arterial wall tissue.
Fifty-four tissue samples from 31 AAA patients (30♂; max. diameter Dmax 5.98 ± 1.42 cm) were excised from the aneurysm sac. Samples were divided for corresponding immunohistological and mechanical analysis. Collagen I and III, total collagen, elastin, and proteoglycans were quantified by computational image analysis of histological staining. Pre-surgical CT data were used for 3D segmentation of the AAA and calculation of mechanical conditions by advanced finite element analysis. AAA wall stiffness and strength were assessed by repeated cyclical, sinusoidal and destructive tensile testing.
Amounts of collagen I, III, and total collagen were increased with higher local wall stress (p = .002, .017, .030, respectively) and strain (p = .002, .012, .020, respectively). AAA wall failure tension exhibited a positive correlation with collagen I, total collagen, and proteoglycans (p = .037, .038, .022, respectively). α-Stiffness correlated with collagen I, III, and total collagen (p = .011, .038, and .008), while β-stiffness correlated only with proteoglycans (p = .028). In contrast, increased thrombus thickness was associated with decreased collagen I, III, and total collagen (p = .003, .020, .015, respectively), and AAA diameter was negatively associated with elastin (p = .006).
The present results indicate that in AAA, increased locally acting biomechanical conditions (stress and strain) involve increased synthesis of collagen and proteoglycans with increased failure tension. These findings confirm the presence of adaptive biological processes to maintain the mechanical stability of AAA wall.
关于细胞外基质 (ECM) 蛋白与局部作用的机械条件和材料宏观特性之间的相互作用，在腹主动脉瘤 (AAA) 中知之甚少。在这项研究中，研究了 ECM 成分与动脉瘤壁组织中相应的生物力学特性和载荷之间的相关性。
从 31 名 AAA 患者 (30 名男性；最大直径 Dmax 5.98±1.42cm) 的动脉瘤囊中切除了 54 个组织样本。将样本分为相应的免疫组织化学和力学分析。通过组织学染色的计算图像分析定量测定胶原 I 和 III、总胶原、弹性蛋白和蛋白聚糖。使用术前 CT 数据对 AAA 进行 3D 分割，并通过高级有限元分析计算力学条件。通过重复循环、正弦和破坏性拉伸测试评估 AAA 壁的刚度和强度。
胶原 I、III 和总胶原的含量随局部壁应力 (p=.002，p=.017，p=.030) 和应变 (p=.002，p=.012，p=.020) 的增加而增加。AAA 壁失效张力与胶原 I、总胶原和蛋白聚糖呈正相关 (p=.037，p=.038，p=.022)。α-刚度与胶原 I、III 和总胶原相关 (p=.011，p=.038 和 p=.008)，而 β-刚度仅与蛋白聚糖相关 (p=.028)。相比之下，血栓厚度的增加与胶原 I、III 和总胶原的减少相关 (p=.003，p=.020，p=.015)，AAA 直径与弹性蛋白呈负相关 (p=.006)。
本研究结果表明，在 AAA 中，局部作用的生物力学条件（应力和应变）的增加涉及胶原和蛋白聚糖合成的增加，以及失效张力的增加。这些发现证实了存在适应性生物过程来维持 AAA 壁的机械稳定性。
