Luo Yuemei, Cui Dongyao, Yu Xiaojun, Chen Si, Liu Xinyu, Tang Hongying, Wang Xianghong, Liu Linbo
School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, Singapore.
School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, Singapore.
PLoS One. 2016 May 5;11(5):e0155117. doi: 10.1371/journal.pone.0155117. eCollection 2016.
Plaque rupture is the critical cause of cardiovascular thrombosis, but the detailed mechanisms are not fully understood. Recent studies have found abundant cholesterol crystals in ruptured plaques, and it has been proposed that the rapid expansion of cholesterol crystals in a limited space during crystallization may contribute to plaque rupture. To evaluate the effect of cholesterol crystal growth on atherosclerotic plaques, we modeled the expansion of cholesterol crystals during the crystallization process in the necrotic core and estimated the stress on the thin cap with different arrangements of cholesterol crystals. We developed a two-dimensional finite element method model of atherosclerotic plaques containing expanding cholesterol crystals and investigated the effect of the magnitude and distribution of crystallization on the peak circumferential stress born by the cap. Using micro-optical coherence tomography (μOCT), we extracted the cross-sectional geometric information of cholesterol crystals in human atherosclerotic aorta tissue ex vivo and applied the information to the model. The results demonstrate that (1) the peak circumference stress is proportionally dependent on the cholesterol crystal growth; (2) cholesterol crystals at the cap shoulder impose the highest peak circumference stress; and (3) spatial distributions of cholesterol crystals have a significant impact on the peak circumference stress: evenly distributed cholesterol crystals exert less peak circumferential stress on the cap than concentrated crystals.
斑块破裂是心血管血栓形成的关键原因，但其详细机制尚未完全明确。近期研究发现破裂斑块中存在大量胆固醇结晶，有人提出胆固醇结晶在结晶过程中于有限空间内的快速膨胀可能促使斑块破裂。为评估胆固醇结晶生长对动脉粥样硬化斑块的影响，我们模拟了坏死核心中结晶过程中胆固醇结晶的膨胀，并估算了不同胆固醇结晶排列情况下薄纤维帽上的应力。我们构建了含膨胀胆固醇结晶的动脉粥样硬化斑块二维有限元模型，研究了结晶大小和分布对纤维帽所承受的峰值周向应力的影响。利用微光学相干断层扫描（μOCT），我们离体提取了人类动脉粥样硬化主动脉组织中胆固醇结晶的横截面几何信息，并将该信息应用于模型。结果表明：（1）峰值周向应力与胆固醇结晶生长成比例相关；（2）纤维帽肩部的胆固醇结晶产生的峰值周向应力最高；（3）胆固醇结晶的空间分布对峰值周向应力有显著影响：均匀分布的胆固醇结晶对纤维帽施加的峰值周向应力小于集中分布的结晶。
