Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, PA, 18015, USA.
Department of Biomedical Informatics, Emory University, Atlanta, GA, 30322, USA.
Comput Biol Med. 2024 Oct;181:109035. doi: 10.1016/j.compbiomed.2024.109035. Epub 2024 Aug 29.
The stomach, a central organ in the Gastrointestinal (GI) tract, regulates the processing of ingested food through gastric motility and emptying. Understanding the stomach function is crucial for treating gastric disorders. Experimental studies in this field often face difficulties due to limitations and invasiveness of available techniques and ethical concerns. To counter this, researchers resort to computational and numerical methods. However, existing computational studies often isolate one aspect of the stomach function while neglecting the rest and employ computationally expensive methods. This paper proposes a novel cost-efficient multi-compartmental model, offering a comprehensive insight into gastric function at an organ level, thus presenting a promising alternative. The proposed approach divides the spatial geometry of the stomach into four compartments: Proximal/Middle/Terminal antrum and Pyloric sphincter. Each compartment is characterized by a set of ordinary differential equations (ODEs) with respect to time to characterize the stomach function. Electrophysiology is represented by simplified equations reflecting the "slow wave behavior" of Interstitial Cells of Cajal (ICC) and Smooth Muscle Cells (SMC) in the stomach wall. An electro-mechanical coupling model translates SMC "slow waves" into smooth muscle contractions. Muscle contractions induce peristalsis, affecting gastric fluid flow velocity and subsequent emptying when the pyloric sphincter is open. Contraction of the pyloric sphincter initiates a retrograde flow jet at the terminal antrum, modeled by a circular liquid jet flow equation. The results from the proposed model for a healthy human stomach were compared with experimental and computational studies on electrophysiology, muscle tissue mechanics, and fluid behavior during gastric emptying. These findings revealed that each "ICC" slow wave corresponded to a muscle contraction due to electro-mechanical coupling behavior. The rate of gastric emptying and mixing efficiency decreased with increasing viscosity of gastric liquid but remained relatively unchanged with gastric liquid density variations. Utilizing different ODE solvers in MATLAB, the model was solved, with ode15s demonstrating the fastest computation time, simulating 180 s of real-time stomach response in just 2.7 s. This multi-compartmental model signifies a promising advancement in understanding gastric function, providing a cost-effective and comprehensive approach to study complex interactions within the stomach and test innovative therapies like neuromodulation for treating gastric disorders.
胃是胃肠道（GI）的一个中心器官，通过胃动力和排空来调节摄入食物的处理。了解胃的功能对于治疗胃疾病至关重要。由于现有技术的局限性和侵入性以及伦理问题，该领域的实验研究经常面临困难。为了解决这个问题，研究人员求助于计算和数值方法。然而，现有的计算研究往往忽略了胃功能的其他方面，只孤立地研究一个方面，并且采用计算成本高昂的方法。本文提出了一种新颖的、具有成本效益的多腔室模型，为器官水平的胃功能提供了全面的见解，因此是一种很有前途的替代方法。该方法将胃的空间几何形状分为四个腔室：近端/中部/末端胃窦和幽门括约肌。每个腔室都有一组关于时间的常微分方程（ODE），用于描述胃的功能。电生理学由简化方程表示，反映了胃壁中环肌细胞（ICC）和平滑肌细胞（SMC）的“慢波行为”。电机械耦合模型将 SMC“慢波”转化为平滑肌收缩。肌肉收缩引起蠕动，当幽门括约肌打开时，影响胃内流体流动速度和随后的排空。幽门括约肌的收缩在末端胃窦引发一个反向射流射流，由圆形液体射流方程来模拟。与健康人体胃的电生理学、肌肉组织力学和胃排空期间液体行为的实验和计算研究相比，提出的模型的结果表明，每个“ICC”慢波对应于电机械耦合行为引起的肌肉收缩。胃排空率和混合效率随着胃液体粘度的增加而降低，但随着胃液体密度的变化而相对不变。在 MATLAB 中使用不同的 ODE 求解器来求解模型，ode15s 显示最快的计算时间，仅用 2.7s 即可模拟 180s 的实时胃反应。这种多腔室模型是对胃功能理解的一个有希望的进展，提供了一种具有成本效益的综合方法来研究胃内的复杂相互作用，并测试新的治疗方法，如神经调节，以治疗胃疾病。
