A Phenomenological-Based Model for the Small Intestine Role in Human Glucose Homeostasis

Abstract

Some models representing the human gastrointestinal tract have been formulated in the literature, but a small intestine model and its role in glucose homeostasis including nutrient digestion and enzymatic activity does not exist. This work presents a phenomenological-based semi-physical model (PBSM) to describe the role of the small intestine in glucose homeostasis in the human body. The small intestine is modeled as a plug-flow reactor with three process systems (PS), intestinal lumen, enterocytes, and bloodstream. At every PS, mass balances are performed over the main involved species. Then, the equations with relevant information to answer the model question are selected. Model parameters for an average person were adjusted using experimental data retrieved from the literature. The results show the dynamic evolution of macronutrients degradation in the small intestine, as well as the absorption of glucose, fatty acids, and amino acids into the bloodstream. Moreover, this model provides the dynamic behavior of the enzymatic activity and water, as food passes through the small intestine. Finally, the glucose appearance in the bloodstream is reported. The characteristics of the proposed model allow a reliable representation of the physiology of digestion and absorption of nutrients in the small intestine, for this reason, it can be used in the construction of an artificial pancreas.