NASA, 2101 NASA Parkway Building 13 R 208, Houston, TX 77058.
Stanford Synchrotron Radiation Lightsource, 2575 Sand Hill Road, Menlo Park, CA 94025.
J Biomech Eng. 2022 Feb 1;144(2). doi: 10.1115/1.4052432.
Atherosclerotic plaques can gradually develop in certain arteries. Disruption of fibrous tissue in plaques can result in plaque rupture and thromboembolism, leading to heart attacks and strokes. Collagen fibrils are important tissue building blocks and tissue strength depends on how fibrils are oriented. Fibril orientation in plaque tissue may potentially influence vulnerability to disruption. While X-ray scattering has previously been used to characterize fibril orientations in soft tissues and bones, it has never been used for characterization of human atherosclerotic plaque tissue. This study served to explore fibril orientation in specimens from human plaques using small angle X-ray scattering (SAXS). Plaque tissue was extracted from human femoral and carotid arteries, and each tissue specimen contained a region of calcified material. Three-dimensional (3D) collagen fibril orientation was determined along scan lines that started away from and then extended toward a given calcification. Fibrils were found to be oriented mainly in the circumferential direction of the plaque tissue at the majority of locations away from calcifications. However, in a number of cases, the dominant fibril direction differed near a calcification, changing from circumferential to longitudinal or thickness (radial) directions. Further study is needed to elucidate how these fibril orientations may influence plaque tissue stress-strain behavior and vulnerability to rupture.
动脉粥样硬化斑块可在某些动脉中逐渐形成。斑块中纤维组织的破裂可导致斑块破裂和血栓栓塞，从而导致心脏病发作和中风。胶原纤维是重要的组织构建块，组织强度取决于纤维的取向。斑块组织中的纤维取向可能会影响其易破裂性。虽然 X 射线散射以前曾用于表征软组织和骨骼中的纤维取向，但从未用于表征人类动脉粥样硬化斑块组织。本研究旨在使用小角度 X 射线散射（SAXS）探索人斑块标本中的纤维取向。从人股动脉和颈动脉中提取斑块组织，每个组织标本都包含钙化物质区域。在远离给定钙化的扫描线上确定三维（3D）胶原纤维的取向，然后向其延伸。发现在远离钙化的大多数位置，纤维主要沿斑块组织的周向方向取向。然而，在许多情况下，在钙化附近，主要纤维方向发生变化，从周向变为纵向或厚度（径向）方向。需要进一步研究阐明这些纤维取向如何影响斑块组织的应力-应变行为和易破裂性。
