Cargando…

Variation of Passive Biomechanical Properties of the Small Intestine along Its Length: Microstructure-Based Characterization

Multiaxial testing of the small intestinal wall is critical for understanding its biomechanical properties and defining material models, but limited data and material models are available. The aim of the present study was to develop a microstructure-based material model for the small intestine and t...

Descripción completa

Detalles Bibliográficos
Autor principal: Sokolis, Dimitrios P.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7996941/
https://www.ncbi.nlm.nih.gov/pubmed/33652760
http://dx.doi.org/10.3390/bioengineering8030032
_version_ 1783670215689633792
author Sokolis, Dimitrios P.
author_facet Sokolis, Dimitrios P.
author_sort Sokolis, Dimitrios P.
collection PubMed
description Multiaxial testing of the small intestinal wall is critical for understanding its biomechanical properties and defining material models, but limited data and material models are available. The aim of the present study was to develop a microstructure-based material model for the small intestine and test whether there was a significant variation in the passive biomechanical properties along the length of the organ. Rat tissue was cut into eight segments that underwent inflation/extension testing, and their nonlinearly hyper-elastic and anisotropic response was characterized by a fiber-reinforced model. Extensive parametric analysis showed a non-significant contribution to the model of the isotropic matrix and circumferential-fiber family, leading also to severe over-parameterization. Such issues were not apparent with the reduced neo-Hookean and (axial and diagonal)-fiber family model, that provided equally accurate fitting results. Absence from the model of either the axial or diagonal-fiber families led to ill representations of the force- and pressure-diameter data, respectively. The primary direction of anisotropy, designated by the estimated orientation angle of diagonal-fiber families, was about 35° to the axial direction, corroborating prior microscopic observations of submucosal collagen-fiber orientation. The estimated model parameters varied across and within the duodenum, jejunum, and ileum, corroborating histologically assessed segmental differences in layer thicknesses.
format Online
Article
Text
id pubmed-7996941
institution National Center for Biotechnology Information
language English
publishDate 2021
publisher MDPI
record_format MEDLINE/PubMed
spelling pubmed-79969412021-03-27 Variation of Passive Biomechanical Properties of the Small Intestine along Its Length: Microstructure-Based Characterization Sokolis, Dimitrios P. Bioengineering (Basel) Article Multiaxial testing of the small intestinal wall is critical for understanding its biomechanical properties and defining material models, but limited data and material models are available. The aim of the present study was to develop a microstructure-based material model for the small intestine and test whether there was a significant variation in the passive biomechanical properties along the length of the organ. Rat tissue was cut into eight segments that underwent inflation/extension testing, and their nonlinearly hyper-elastic and anisotropic response was characterized by a fiber-reinforced model. Extensive parametric analysis showed a non-significant contribution to the model of the isotropic matrix and circumferential-fiber family, leading also to severe over-parameterization. Such issues were not apparent with the reduced neo-Hookean and (axial and diagonal)-fiber family model, that provided equally accurate fitting results. Absence from the model of either the axial or diagonal-fiber families led to ill representations of the force- and pressure-diameter data, respectively. The primary direction of anisotropy, designated by the estimated orientation angle of diagonal-fiber families, was about 35° to the axial direction, corroborating prior microscopic observations of submucosal collagen-fiber orientation. The estimated model parameters varied across and within the duodenum, jejunum, and ileum, corroborating histologically assessed segmental differences in layer thicknesses. MDPI 2021-02-26 /pmc/articles/PMC7996941/ /pubmed/33652760 http://dx.doi.org/10.3390/bioengineering8030032 Text en © 2021 by the author. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) ).
spellingShingle Article
Sokolis, Dimitrios P.
Variation of Passive Biomechanical Properties of the Small Intestine along Its Length: Microstructure-Based Characterization
title Variation of Passive Biomechanical Properties of the Small Intestine along Its Length: Microstructure-Based Characterization
title_full Variation of Passive Biomechanical Properties of the Small Intestine along Its Length: Microstructure-Based Characterization
title_fullStr Variation of Passive Biomechanical Properties of the Small Intestine along Its Length: Microstructure-Based Characterization
title_full_unstemmed Variation of Passive Biomechanical Properties of the Small Intestine along Its Length: Microstructure-Based Characterization
title_short Variation of Passive Biomechanical Properties of the Small Intestine along Its Length: Microstructure-Based Characterization
title_sort variation of passive biomechanical properties of the small intestine along its length: microstructure-based characterization
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7996941/
https://www.ncbi.nlm.nih.gov/pubmed/33652760
http://dx.doi.org/10.3390/bioengineering8030032
work_keys_str_mv AT sokolisdimitriosp variationofpassivebiomechanicalpropertiesofthesmallintestinealongitslengthmicrostructurebasedcharacterization