TY - JOUR
T1 - A fully resolved active musculo-mechanical model for esophageal transport
AU - Kou, Wenjun
AU - Bhalla, Amneet Pal Singh
AU - Griffith, Boyce E.
AU - Pandolfino, John E.
AU - Kahrilas, Peter J.
AU - Patankar, Neelesh A.
N1 - Funding Information:
The support of grant R01 DK079902 (J.E.P.) and R01 DK056033 (P.J.K.) from the National Institutes of Health , USA is gratefully acknowledged. B.E.G. acknowledges research support from the National Science Foundation (NSF awards DMS-1016554 and ACI-1047734 ).
Publisher Copyright:
© 2015 Elsevier Inc.
PY - 2015/10/1
Y1 - 2015/10/1
N2 - Esophageal transport is a physiological process that mechanically transports an ingested food bolus from the pharynx to the stomach via the esophagus, a multi-layered muscular tube. This process involves interactions between the bolus, the esophagus, and the neurally coordinated activation of the esophageal muscles. In this work, we use an immersed boundary (IB) approach to simulate peristaltic transport in the esophagus. The bolus is treated as a viscous fluid that is actively transported by the muscular esophagus, and the esophagus is modeled as an actively contracting, fiber-reinforced tube. Before considering the full model of the esophagus, however, we first consider a standard benchmark problem of flow past a cylinder. Next a simplified version of our model is verified by comparison to an analytic solution to the tube dilation problem. Finally, three different complex models of the multi-layered esophagus, which differ in their activation patterns and the layouts of the mucosal layers, are extensively tested. To our knowledge, these simulations are the first of their kind to incorporate the bolus, the multi-layered esophagus tube, and muscle activation into an integrated model. Consistent with experimental observations, our simulations capture the pressure peak generated by the muscle activation pulse that travels along the bolus tail. These fully resolved simulations provide new insights into roles of the mucosal layers during bolus transport. In addition, the information on pressure and the kinematics of the esophageal wall resulting from the coordination of muscle activation is provided, which may help relate clinical data from manometry and ultrasound images to the underlying esophageal motor function.
AB - Esophageal transport is a physiological process that mechanically transports an ingested food bolus from the pharynx to the stomach via the esophagus, a multi-layered muscular tube. This process involves interactions between the bolus, the esophagus, and the neurally coordinated activation of the esophageal muscles. In this work, we use an immersed boundary (IB) approach to simulate peristaltic transport in the esophagus. The bolus is treated as a viscous fluid that is actively transported by the muscular esophagus, and the esophagus is modeled as an actively contracting, fiber-reinforced tube. Before considering the full model of the esophagus, however, we first consider a standard benchmark problem of flow past a cylinder. Next a simplified version of our model is verified by comparison to an analytic solution to the tube dilation problem. Finally, three different complex models of the multi-layered esophagus, which differ in their activation patterns and the layouts of the mucosal layers, are extensively tested. To our knowledge, these simulations are the first of their kind to incorporate the bolus, the multi-layered esophagus tube, and muscle activation into an integrated model. Consistent with experimental observations, our simulations capture the pressure peak generated by the muscle activation pulse that travels along the bolus tail. These fully resolved simulations provide new insights into roles of the mucosal layers during bolus transport. In addition, the information on pressure and the kinematics of the esophageal wall resulting from the coordination of muscle activation is provided, which may help relate clinical data from manometry and ultrasound images to the underlying esophageal motor function.
KW - Esophageal transport
KW - Fluid-structure interaction
KW - Immersed boundary method
KW - Muscle activation
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U2 - 10.1016/j.jcp.2015.05.049
DO - 10.1016/j.jcp.2015.05.049
M3 - Article
C2 - 26190859
AN - SCOPUS:84934343950
VL - 298
SP - 446
EP - 465
JO - Journal of Computational Physics
JF - Journal of Computational Physics
SN - 0021-9991
ER -