Effects of Blood Flow on Insulin Concentration: A Modelling Study

Abstract

Pancreatic islets are highly vascularized micro-organs composed of glucagon-secreting $\alpha$ cells, insulin-secreting $\beta$-cells and somatostatin-secreting $\delta$-cells. Within the islets, the exchange of nutrients and hormones, as well as paracrine communication between islet cells, rely on a dense network of capillaries that allows the pancreatic hormones to travel throughout the islet before reaching the systemic circulation. Based on experimental observations, three models for islet vasculature have been proposed: pole-to-pole, center-to-periphery and periphery-to-center. However, despite its importance, the structure and functional role of the islet vasculature remains an open question. In this work, we developed computational models of the three vasculature models, aiming to evaluate the effect of the vasculature on the concentration of insulin reached within the islets. According to our results, the direction of blood flow could have a key role for the intraislet paracrine signaling by directing the hormones signals towards certain regions of the islet.