Biomechanical behavior and histological organization of the three-layered passive esophagus as a function of topography

Abstract

The zero-stress state of the mucosa-submucosa and two muscle esophageal layers has been delineated, but their multi-axial response has not, because muscle dissection may not leave tubular specimens intact for inflation/extension testing. The histomechanical behavior of the three-layered porcine esophagus was investigated in this study, through light microscopic examination and uniaxial tension, with two-dimensional strain measurement in pairs of orthogonally oriented specimens. The two-dimensional Fung-type strain-energy function described suitably the pseudo-elastic tissue response, affording faithful simulations to our data. Differences in the scleroprotein content and configuration were identified as a function of layer, topography, and orientation, substantiating the macromechanical differences found. In view of the failure and optimized material parameters, the mucosa-submucosa was stronger and stiffer than muscle, associating it with a higher collagen content. A notable topographical distribution was apparent, with data for the abdominal region differentiated from that for the cervical region, owing to the existence of inner muscle with a circumferential arrangement and of outer muscle with a longitudinal arrangement in the former region, and of both muscle layers with oblique arrangement in the latter region, with thoracic esophagus being a transition zone. Tissue from the mucosa-submucosa was stronger and stiffer longitudinally, relating with a preferential collagen reinforcement along that axis, but more extensible in the orthogonal axis.

Migration resistance of esophageal stents: The role of stent design

“…This might cause the esophagus damage and failure. Stavropoulou et al [35] studied the failure criteria for mucosa-submucosa and muscle layers of esophagus. The ultimate tensile strength of mucosa-submucosa and muscle layers were reported as 1149 kPa and 425-530 kPa, respectively.…”

The Esophagiome: concept, status, and future perspectives

“…Significant research related to the Esophagiome has been published by many interdisciplinary groups; however, much of this mechanics‐ and modeling‐based research has not yet been integrated into the GI clinical sciences, where the greatest potential impact might be realized. The Esophagiome remains in its infancy in a community that is dominated by applied clinicians and biological scientists.…”

“…27,28,38,77 Similar to other biological vessels, the esophageal wall undergoes large deformations during bolus transport, and esophageal tissue exhibits nonlinear, pseudoelastic, and anisotropic material properties. 28,33,34,78,79 Hence, the mechanical response of the esophagus is typically represented with large deformation models, such as the Fung-type exponential constitutive model 28,33,35,78,80 and anisotropic microstructure-motivated models. 33,52,79,[81][82][83][84] In the Fung model, esophageal layers are treated as anisotropic and homogeneous materials, while, in the microstructure models, esophageal layers are treated as composite materials, characterized by anisotropic behavior with reinforced fibers in specific orientations.…”

Measuring the micromechanical properties of oesophageal mucosa with atomic force microscopy

“…Vanags et al [17] studied the mechanical properties of the oesophagus at various ages and anatomic sections through inflation and tensile experiments and concluded that the mechanical properties were related to its microstructure. Sokolis built a series of constitutive models for the different layers of the oesophagus based on inflation‐extension responses, uniaxial tensile behaviours and relevant histological observations; additionally, his group studied the differences between different oesophageal regions in detail and found that the contents of elastin and collagen were the least for thoracic oesophagus [20]. Meanwhile, Lin et al [9, 10] studied the friction behaviours of oesophagus under different normal loads, velocities, and extend directions to simulate the endoscopy and they concluded that the coefficient of friction of the oesophagus increased with increasing sliding velocities and decreased with increasing normal loads.…”