Mechanical modeling of lung alveoli: from macroscopic behaviour to cell mechano-sensing at microscopic level

Beltrán, Gabriel ; Navajas, Daniel ; García-Aznar, José Manuel (Universidad de Zaragoza)

Resumen: The mechanical signals sensed by the alveolar cells through the changes in the local matrix stiffness of the extracellular matrix (ECM) are determinant for regulating cellular functions. Therefore, the study of the mechanical response of lung tissue becomes a fundamental aspect in order to further understand the mechanosensing signals perceived by the cells in the alveoli. This study is focused on the development of a finite element (FE) model of a decellularized rat lung tissue strip, which reproduces accurately the mechanical behaviour observed in the experiments by means of a tensile test. For simulating the complex structure of the lung parenchyma, which consists of a heterogeneous and non-uniform network of thin-walled alveoli, a 3D model based on a Voronoi tessellation is developed. This Voronoi-based model is considered very suitable for recreating the geometry of cellular materials with randomly distributed polygons like in the lung tissue. The material model used in the mechanical simulations of the lung tissue was characterized experimentally by means of AFM tests in order to evaluate the lung tissue stiffness on the micro scale. Thus, in this study, the micro (AFM test) and the macro scale (tensile test) mechanical behaviour are linked through the mechanical simulation with the 3D FE model based on Voronoi tessellation. Finally, a micro-mechanical FE-based model is generated from the Voronoi diagram for studying the stiffness sensed by the alveolar cells in function of two independent factors: the stretch level of the lung tissue and the geometrical position of the cells on the extracellular matrix (ECM), distinguishing between pneumocyte type I and type II. We conclude that the position of the cells within the alveolus has a great influence on the local stiffness perceived by the cells. Alveolar cells located at the corners of the alveolus, mainly type II pneumocytes, perceive a much higher stiffness than those located in the flat areas of the alveoli, which correspond to type I pneumocytes. However, the high stiffness, due to the macroscopic lung tissue stretch, affects both cells in a very similar form, thus no significant differences between them have been observed.

Idioma: Inglés

DOI: 10.1016/j.jmbbm.2021.105043

Año: 2022

Publicado en: Journal of the Mechanical Behavior of Biomedical Materials 126 (2022), 105043 [8 pp]
ISSN: 1751-6161

Factor impacto JCR: 3.9 (2022)

Categ. JCR: ENGINEERING, BIOMEDICAL rank: 44 / 96 = 0.458 (2022) - Q2 - T2
Categ. JCR: MATERIALS SCIENCE, BIOMATERIALS rank: 27 / 45 = 0.6 (2022) - Q3 - T2

Factor impacto CITESCORE: 6.8 - Materials Science (Q1) - Engineering (Q1)

Factor impacto SCIMAGO: 0.725 - Biomaterials (Q2) - Mechanics of Materials (Q2) - Biomedical Engineering (Q2)

Financiación: info:eu-repo/grantAgreement/EC/H2020/812772 /EU/Biomechanics in health and disease: advanced physical tools for innovative early diagnosis/Phys2BioMed
Financiación: info:eu-repo/grantAgreement/EC/H2020/826494/EU/PRedictive In-silico Multiscale Analytics to support cancer personalized diaGnosis and prognosis, Empowered by imaging biomarkers/PRIMAGE
Financiación: info:eu-repo/grantAgreement/ES/MICINN/RTI2018-094494-B-C21

Tipo y forma: Article (Published version)

Área (Departamento): Área Mec.Med.Cont. y Teor.Est. (Dpto. Ingeniería Mecánica)