The Layered Structure of Coronary Adventitia under Mechanical Load
The Layered Structure of Coronary Adventitia under Mechanical Load
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DOI：
10.1016/j.bpj.2011.10.043
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发表时间：
2011-12-07
影响因子：
3.4
通讯作者：
Kassab, Ghassan S.
中科院分区：
文献类型：
--
作者：
Chen, Huan;Liu, Yi;Kassab, Ghassan S.
弹性蛋白和胶原纤维束的机械载荷-变形关系是理解组织的微观结构特性的基础。在这里，我们使用多光子显微镜获得定量数据的弹性蛋白和胶原纤维束下原位加载冠状动脉外膜。在未染色的新鲜冠状动脉外膜上进行同步加载成像实验，可以对胶原和弹性蛋白原纤维束及其各自的变形进行形态学测量。在五个不同的扩张加载点（周向拉伸比λ（θ）= 1.0，1.2，1.4，1.6和1.8），在生理轴向拉伸比λ（轴向）= 1.3的纤维数据进行了分析。四个纤维几何参数被用来量化纤维：取向角，波纹度，宽度和面积分数。结果表明，内外膜中的弹性蛋白纤维和胶原纤维形成同心密排的纤维片，纤维取向角、宽度和面积分数在跨壁方向上各不相同。纤维变形的程度取决于在无膨胀状态下的初始取向角（λ（θ）= 1.0和λ（轴向）= 1.3）。在较高的扩张载荷下，纤维的取向角和波纹度线性减小，但胶原纤维的宽度在λ（θ）= 1.0-1.4时相对恒定，然后在λ（θ）>= 1.4时线性减小。胶原纤维波纹度的相对分散度（SD/平均值）的降低表明对载荷的不均匀机械响应。这项研究为冠状动脉生物力学提供了基本的微观结构数据，我们认为它对结构模型具有开创性意义。
The mechanical loading-deformation relation of elastin and collagen fibril bundles is fundamental to understanding the microstructural properties of tissue. Here, we use multiphoton microscopy to obtain quantitative data of elastin and collagen fiber bundles under in situ loading of coronary adventitia. Simultaneous loading-imaging experiments on unstained fresh coronary adventitia allowed morphometric measurements of collagen and elastin fibril bundles and their individual deformation. Fiber data were analyzed at five different distension loading points (circumferential stretch ratio lambda(theta) = 1.0, 1.2, 1.4, 1.6, and 1.8) at a physiological axial stretch ratio of lambda(axial) = 1.3. Four fiber geometrical parameters were used to quantify the fibers: orientation angle, waviness, width, and area fraction. The results show that elastin and collagen fibers in inner adventitia form concentric densely packed fiber sheets, and the fiber orientation angle, width, and area fraction vary transmurally. The extent of fiber deformation depends on the initial orientation angle at no-distension state (lambda(theta) = 1.0 and lambda(axial) = 1.3). At higher distension loading, the orientation angle and waviness of fibers decrease linearly, but the width of collagen fiber is relatively constant at lambda(theta) = 1.0-1.4 and then decrease linearly for lambda(theta) >= 1.4. A decrease of the relative dispersion (SD/mean) of collagen fiber waviness suggests a heterogeneous mechanical response to loads. This study provides fundamental microstructural data for coronary artery biomechanics and we consider it seminal for structural models.