Kobielarz Magdalena, Kozuń Marta, Gąsior-Głogowska Marlena, Chwiłkowska Agnieszka
Wroclaw University of Science and Technology, Faculty of Mechanical Engineering, Department of Mechanics, Materials and Biomedical Engineering, 7/9 Lukasiewicz Str., 50-371, Wroclaw, Poland.
Wroclaw University of Science and Technology, Faculty of Mechanical Engineering, Department of Mechanics, Materials and Biomedical Engineering, 7/9 Lukasiewicz Str., 50-371, Wroclaw, Poland.
J Mech Behav Biomed Mater. 2020 Sep;109:103837. doi: 10.1016/j.jmbbm.2020.103837. Epub 2020 May 4.
Atherosclerotic plaques are characterized by structural heterogeneity affecting aortic behaviour under mechanical loading. There is evidence of direct connections between the structural plaque arrangement and the risk of plaque rupture. As a consequence of aortic plaque rupture, plaque components are transferred by the bloodstream to smaller vessels, resulting in acute cardiovascular events with a poor prognosis, such as heart attacks or strokes. Hence, evaluation of the composition, structure, and biochemical profile of atherosclerotic plaques seems to be of great importance to assess the properties of a mechanically induced failure, indicating the strength and rupture vulnerability of plaque. The main goal of the research was to determine experimentally under uniaxial loading the mechanical properties of different types of the human abdominal aorta and human aortic atherosclerotic plaques identified based on vibrational spectra (ATR-FTIR and FT-Raman spectroscopy) analysis and validated by histological staining. The potential of spectroscopic techniques as a useful histopathological tool was demonstrated. Three types of atherosclerotic plaques - predominantly calcified (APC), lipid (APL), and fibrotic (APF) - were distinguished and confirmed by histopathological examinations. Compared to the normal aorta, fibrotic plaques were stiffer (median of E for circumferential and axial directions, respectively: 8.15 MPa and 6.56 MPa) and stronger (median of σ for APLc = 1.57 MPa and APLa = 1.64 MPa), lipidic plaques were the weakest (median of σ for APLc = 0.76 MPa and APLa = 0.51 MPa), and calcified plaques were the stiffest (median of E for circumferential and axial directions, respectively: 13.23 MPa and 6.67 MPa). Therefore, plaques detected as predominantly lipid and calcified are most prone to rupture; however, the failure process reflected by the simplification of the stress-stretch characteristics seems to vary depending on the plaque composition.
动脉粥样硬化斑块的特征是结构异质性，这会影响主动脉在机械负荷下的行为。有证据表明斑块的结构排列与斑块破裂风险之间存在直接联系。主动脉斑块破裂的结果是，斑块成分通过血流转移到较小的血管，导致预后不良的急性心血管事件，如心脏病发作或中风。因此，评估动脉粥样硬化斑块的组成、结构和生化特征对于评估机械诱导失效的特性似乎非常重要，这表明了斑块的强度和破裂易损性。该研究的主要目标是在单轴加载下通过实验确定基于振动光谱（衰减全反射傅里叶变换红外光谱和傅里叶变换拉曼光谱）分析识别并经组织学染色验证的不同类型的人体腹主动脉和人体主动脉粥样硬化斑块的力学性能。证明了光谱技术作为一种有用的组织病理学工具的潜力。通过组织病理学检查区分并确认了三种类型的动脉粥样硬化斑块——主要为钙化斑块（APC）、脂质斑块（APL）和纤维化斑块（APF）。与正常主动脉相比，纤维化斑块更硬（周向和轴向方向的弹性模量中位数分别为：8.15MPa和6.56MPa）且更强（APLc的屈服强度中位数=1.57MPa，APLa的屈服强度中位数=1.64MPa），脂质斑块最薄弱（APLc的屈服强度中位数=0.76MPa，APLa的屈服强度中位数=0.51MPa），钙化斑块最硬（周向和轴向方向的弹性模量中位数分别为：13.23MPa和6.67MPa）。因此，检测为主要是脂质和钙化的斑块最容易破裂；然而，应力-应变特性简化所反映的失效过程似乎因斑块组成而异。
