Sensation and distribution of stress and deformation in the human oesophagus

Abstract

Evaluation of the distribution of stresses and strains in relation to distension-induced sensation in the human oesophagus is valuable for understanding oesophageal biomechanics and mechano-sensation. In 12 healthy volunteers a specially designed oesophageal bag containing an endoscopic ultrasound probe was inflated to the moderate pain level. Ultrasound images, bag pressure and perceived sensation were recorded before and after pharmacological relaxation of the smooth muscle with butylscopolamine. The oesophagus was assumed to be circular and thick-walled. Distension induced a tensile circumferential stretch, radial compression and longitudinal shortening. Both circumferential strain and stress were highest at the mucosal surface and decreased throughout the wall. The stiffness increased throughout the wall and was highest at the outer surface (P < 0.001). The decrease in stiffness in response to butylscopolamine was non-significant. The infused volume (P = 0.012) and circumferential stress (P < 0.001) were most closely associated with the distension-induced sensation (adjusted R2 = 0.88). The perceived sensation was highly individual but was unaffected by butylscopolamine (P > 0.08). The present study provides a method for computation of the stress-strain distribution throughout the wall and the mechano-sensory interaction in the human oesophagus. In the future, this may be useful for understanding of mechanoreceptor responses and generation of symptoms in visceral organs in health and in disease.

Mechanosensation and Mucosal Blood Perfusion in the Esophagus of Healthy Volunteers Studied with a Multimodal Device Incorporating Laser Doppler Flowmetry and Endosonography

“…This was not a surprise because motion artifacts from active phasic muscular activity in the esophagus were much less prominent during BSB. The fact that the pain response was not different with or without BSB indicates that pain was dependent on the increasing passive stretch of the wall, whereas the active phasic contractions elicited by bag distension did not contribute to pain, as previously found by Takeda et al [14] and Frøkjaer et al [22].…”

Peptide Hydrogels—A Tissue Engineering Strategy for the Prevention of Oesophageal Strictures

“…Furthermore, the peptide hydrogels that mOECs responded well to (PGD-AlphaProC and PGD-CGD2) also possess similar mechanical properties to the native human oesophagus tissue interface (5-50 KPa). [37] In fact, after media conditioning, the majority of the hydrogels on the panel had G′ values above 5 kPa, except PGD-AlphaProB and PGD-C2.…”

Liquid in the gastroesophageal segment promotes reflux, but compliance does not: a mathematical modeling study

“…Studies done with esophageal muscle from animals have shown that, when axial slices of passive esophageal muscle are cut along its circumference, it tends to open (16,29,33). The "opening angle" is a qualitative measure of "residual tension," the level of circularly oriented passive tension that would be required to reclose the gut segment and return muscle to its precut state.…”

“…We apply this mathematical formalism to model the stress-strain properties of the muscularis propria. All muscle mechanics studies done in the human esophagus, except for two notable exceptions (16,38), have assumed the esophageal wall to be "thin". 1 This incorrect assumption, although leading to great simplification of the mathematics, has important implications to the accuracy of predictions, so we do not make it.…”