Department of Bioengineering, Imperial College London, London SW3 6LR, UK.
National Heart and Lung Institute, Department of Medicine, Imperial College London, London SW3 6LR, UK.
J R Soc Interface. 2024 Feb;21(211):20230674. doi: 10.1098/rsif.2023.0674. Epub 2024 Feb 7.
Nano-indentation techniques might be better equipped to assess the heterogeneous material properties of plaques than macroscopic methods but there are no bespoke protocols for this kind of material testing for coronary arteries. Therefore, we developed a measurement protocol to extract mechanical properties from healthy and atherosclerotic coronary artery tissue sections. Young's modulus was derived from force-indentation data. Metrics of collagen fibre density were extracted from the same tissue, and the local material properties were co-registered to the local collagen microstructure with a robust framework. The locations of the indentation were retrospectively classified by histological category (healthy, plaque, lipid-rich, fibrous cap) according to Picrosirius Red stain and adjacent Hematoxylin & Eosin and Oil-Red-O stains. Plaque tissue was softer ( < 0.001) than the healthy coronary wall. Areas rich in collagen within the plaque (fibrous cap) were significantly ( < 0.001) stiffer than areas poor in collagen/lipid-rich, but less than half as stiff as the healthy coronary media. Young's moduli correlated (Pearson's = 0.53, < 0.05) with collagen content. Atomic force microscopy (AFM) is capable of detecting tissue stiffness changes related to collagen density in healthy and diseased cardiovascular tissue. Mechanical characterization of atherosclerotic plaques with nano-indentation techniques could refine constitutive models for computational modelling.
纳米压痕技术可能比宏观方法更能评估斑块的不均匀材料特性，但对于冠状动脉这种材料的测试还没有专门的协议。因此，我们开发了一种从健康和动脉粥样硬化冠状动脉组织切片中提取力学性能的测量方案。杨氏模量由力-压痕数据得出。从相同的组织中提取胶原纤维密度的指标，并使用稳健的框架将局部材料特性与局部胶原微结构进行配准。根据 Picrosirius Red 染色以及相邻的 Hematoxylin & Eosin 和 Oil-Red-O 染色，根据组织学分类（健康、斑块、富含脂质、纤维帽）对压痕的位置进行回顾性分类。斑块组织比健康的冠状动脉壁更软（<0.001）。斑块中富含胶原的区域（纤维帽）明显比胶原/富含脂质的区域硬（<0.001），但只有健康冠状动脉中层的一半硬。杨氏模量与胶原含量相关（Pearson's = 0.53，<0.05）。原子力显微镜（AFM）能够检测与健康和病变心血管组织中胶原密度相关的组织刚度变化。用纳米压痕技术对动脉粥样硬化斑块进行力学特性表征，可以改进计算模型的本构模型。
