Compromised homeostasis in aged carotid arteries revealed by microstructural studies of elastic lamellae

IF 3.3 2区医学 Q2 ENGINEERING, BIOMEDICAL

Journal of the Mechanical Behavior of Biomedical Materials Pub Date : 2023-10-15 DOI:10.1016/j.jmbbm.2023.106187

Anastasia Gkousioudi , Taisiya Sigaeva , Xunjie Yu , Francesca Seta , Richard D. Wainford , Yanhang Zhang

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Abstract

Healthy arteries are continuously subjected to diverse mechanical stimuli and adapt in order to maintain a mechanical homeostasis which is characterized by a uniform distribution of wall stresses. However, aging may compromise the homeostatic microenvironment within arteries. Structural heterogeneity has been suggested as a potential microstructural mechanism that could lead to homogeneous stress distribution across the arterial wall. Our previous study on the unfolding and stretching of the elastic lamellae revealed the underlying microstructural mechanism for equalizing the circumferential stresses through wall; inner elastic layers are wavier and unfold more than the outer layers which helps to evenly distribute lamellar stretching (Yu et al., 2018). In this study, we investigated the effect of aging on lamellar deformation and its implications for tissue homeostasis. Common carotid arteries from aged mice were imaged under a multi-photon microscope while subjected to biaxial extension and inflation at five different pressures ranging from 0 up to 120 mmHg. Lamellar unfolding during pressurization was then determined from the reconstructed cross-sectional images of elastic lamellae. Tissue-level circumferential stretch was combined with the lamellar unfolding to calculate lamellar stretching. Our results revealed that the straightness gradient of aged elastic lamellae is similar to the young ones. However, during pressurization, the inner elastic lamella of the aged mice unfolded significantly more than the inner layer in young arteries. An important finding of our study is the uneven increase in inter-lamellar space which contributed to a nonuniform stretching of the elastic lamellae of aged mice arteries, elevated stress gradient, and a shifting of the load-bearing component to adventitia. Our results shed light into the complex microstructural mechanisms that take place in aging and adversely affect arterial mechanical behavior and homeostasis.

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弹性薄片微结构研究揭示老龄颈动脉内稳态受损。

健康的动脉持续受到不同的机械刺激并适应，以维持以壁应力均匀分布为特征的机械稳态。然而，衰老可能会损害动脉内的稳态微环境。结构不均匀性被认为是一种潜在的微观结构机制，可能导致动脉壁上均匀的应力分布。我们之前对弹性片层的展开和拉伸的研究揭示了通过壁均衡周向应力的潜在微观结构机制；内部弹性层比外层更波纹，展开得更多，这有助于均匀分布层状拉伸（Yu et al.，2018）。在这项研究中，我们研究了衰老对板层变形的影响及其对组织稳态的影响。来自老年小鼠的颈总动脉在多光子显微镜下成像，同时在0至120mmHg的五种不同压力下进行双轴拉伸和充气。然后根据重建的弹性薄片的横截面图像确定加压期间的薄片展开。将组织水平的周向拉伸和片层展开相结合来计算片层拉伸。结果表明，老化弹性片层的平直度梯度与年轻弹性片层相似。然而，在加压过程中，老年小鼠的内部弹性薄片比年轻动脉的内层展开得更多。我们研究的一个重要发现是片层间间隙的不均匀增加，这导致了老年小鼠动脉弹性片层的不均匀拉伸、应力梯度升高以及承载成分向外膜的转移。我们的研究结果揭示了衰老过程中发生的复杂微观结构机制，这些机制对动脉力学行为和稳态产生了不利影响。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of the Mechanical Behavior of Biomedical Materials 工程技术-材料科学：生物材料

CiteScore

7.20

自引率

7.70%

发文量

505

审稿时长

46 days

期刊介绍： The Journal of the Mechanical Behavior of Biomedical Materials is concerned with the mechanical deformation, damage and failure under applied forces, of biological material (at the tissue, cellular and molecular levels) and of biomaterials, i.e. those materials which are designed to mimic or replace biological materials. The primary focus of the journal is the synthesis of materials science, biology, and medical and dental science. Reports of fundamental scientific investigations are welcome, as are articles concerned with the practical application of materials in medical devices. Both experimental and theoretical work is of interest; theoretical papers will normally include comparison of predictions with experimental data, though we recognize that this may not always be appropriate. The journal also publishes technical notes concerned with emerging experimental or theoretical techniques, letters to the editor and, by invitation, review articles and papers describing existing techniques for the benefit of an interdisciplinary readership.