Mechanical and structural properties of different types of human aortic atherosclerotic plaques

Magdalena Kobielarz; Marta Kozuń; Marlena Gąsior-Głogowska; Agnieszka Chwiłkowska

doi:10.1016/j.jmbbm.2020.103837

Mechanical and structural properties of different types of human aortic atherosclerotic plaques

J Mech Behav Biomed Mater. 2020 Sep:109:103837. doi: 10.1016/j.jmbbm.2020.103837. Epub 2020 May 4.

Authors

Magdalena Kobielarz¹, Marta Kozuń², Marlena Gąsior-Głogowska³, Agnieszka Chwiłkowska⁴

Affiliations

¹ 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. Electronic address: magdalena.kobielarz@pwr.edu.pl.
² 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.
³ Wroclaw University of Science and Technology, Faculty of Fundamental Problems of Technology, Department of Biomedical Engineering, Wrocław University of Technology, Plac Grunwaldzki 13, 50-377, Wroclaw, Poland.
⁴ Wroclaw Medical University, Department of Molecular and Cellular Biology, 211A Borowska Str., 50-556, Wroclaw, Poland.

PMID: 32543403
DOI: 10.1016/j.jmbbm.2020.103837

Abstract

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_H for circumferential and axial directions, respectively: 8.15 MPa and 6.56 MPa) and stronger (median of σ_M for APLc = 1.57 MPa and APLa = 1.64 MPa), lipidic plaques were the weakest (median of σ_M for APLc = 0.76 MPa and APLa = 0.51 MPa), and calcified plaques were the stiffest (median of E_H 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.

Keywords: Atherosclerotic plaques; Calcification; Histology; Human abdominal aorta; Infrared spectroscopy; Mechanical properties; Raman spectroscopy; Uniaxial tensile test.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Aorta
Humans
Plaque, Atherosclerotic*
Rupture