Effect of stomach motility on food hydrolysis and gastric emptying: Insight from computational models

A review of the use of numerical analysis in stomach modeling

Food digestion is important for human health. Advances have been made using in vitro models to study food digestion, but there is considerable potential for numerical approaches in stomach modeling, as they can provide a comprehensive understanding of the complex flow and chemistry in the stomach. The focus of this study is to provide a concise review of the developed numerical stomach models over the past two decades. The gastric physiological parameters that are required for a computational model to represent the human gastric digestion process are discussed, including the stomach geometry, gastric motility, gastric emptying, and gastric secretions. Computational methods used to model gastric digestion are introduced and compared, including different computational fluid dynamics as well as solid mechanics methods. The challenges and limitations of current studies are discussed, as well as the areas for future research that need to be addressed. There has been progress in simulating gastric fluid flow with stomach wall motion, but much work remains to be done. The complex food breakdown mechanisms and a comprehensive chemical digestion process have not been implemented in any developed models. Numerical method that was once computationally expensive will be revolutionized as computing power continues to improve. Ultimately, the advancement of modeling of gastric food digestion will allow for additional hypothesis testing to streamline the development of food products that are beneficial to human health.

In silico modelling of the effect of pyloric intervention procedures on gastric flow and emptying in a stomach with gastroparesis

Pyloric interventions are surgical procedures employed to increase the gastric emptying rate in gastroparesis patients. In this study, we use an in silico model to investigate the consequences of pyloric intervention on gastric flow and emptying for two phenotypes of gastroparesis: antral hypomotility and decreased gastric tone. The transpyloric pressure gradient predicted by the in silico model, based on viscous fluid flow equations, is compared against in vivo measurements. Both phenotypes exhibit a similar pre-procedural emptying rate reduction, but after pyloric surgery, antral hypomotility case with preserved gastric tone shows significant improvements in emptying rates, up to 131%, accompanied by bile reflux from the duodenum into the stomach. Conversely, severely reduced gastric tone cases exhibited a post-procedural reduction in the net emptying rate due to the relatively larger bile reflux. In cases with a combination of antral hypomotility and reduced gastric tone, post-procedural improvements were observed only when both conditions were mild. Our findings highlight the pivotal role of the relative increase in pyloric orifice diameter in determining post-operative emptying rates. The study suggests a possible explanation for the selective response of patients toward these procedures and underscores the potential of in silico modelling to generate valuable insights to inform gastric surgery.