Development of innovative tools for investigation of nutrient-gut interaction

Figure 1 The composition of intestinal epithelial cells along the gastrointestinal tract (left); anatomical features and typical length of different sections of gastrointestinal tract (middle); regionally specific secretion profile of different gut hormones, including ghrelin, cholecystokinin, glucose-dependent insulinotropic polypeptide, glucagon-like peptide 1 and peptide YY (right). CCK: Cholecystokinin; GLP-1: Glucagon-like peptide 1; GIP: Glucose-dependent insulinotropic polypeptide; PYY: Peptide YY.

Figure 2 Schematic of a multichannel intestinal catheter to study regional specificity of nutrient-gut interactions. Multiple channels are opened on the catheter to record the transmucosal potential difference and monitor its position. These channels can also deliver investigational compounds of aspirate luminal samples in a specific region of intestine. The balloon is generally designed to create physical restriction to prevent the fluid flow or the movement of the catheter. TMPD: Transmucosal potential difference.

Figure 3 Comparison of the effect of enteral (proximal or distal) and intravenous (i. v.) isoglycemic glucose administrations on plasma incretin hormone, glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 secretions in healthy subjects and subjects with type 2 diabetes mellitus. A and B: Glucose-dependent insulinotropic polypeptide; C and D: Glucagon-like peptide-1. Asterisk represents P < 0.05 for proximal vs distal enteral glucose infusion; Numbersign represents P < 0.05 for proximal enteral vs corresponding i.v. glycemic glucose infusion; Delta represents P < 0.05 for distal enteral vs corresponding i.v. glycemic glucose infusion. Data are presented as mean ± SEM. GLP-1: Glucagon-like peptide 1; GIP: Glucose-dependent insulinotropic polypeptide; T2DM: Type 2 diabetes mellitus. Citation: Zhang X, Young RL, Bound M, Hu S, Jones KL, Horowitz M, Rayner CK, Wu T. Comparative Effects of Proximal and Distal Small Intestinal Glucose Exposure on Glycemia, Incretin Hormone Secretion, and the Incretin Effect in Health and Type 2 Diabetes. Diabetes Care 2019; 42: 520-528. Copyright© The Authors 2019. Published by American Diabetes Association.

Figure 4 Emerging advanced techniques to study nutrient-gut interaction. A: 2D culture of intestinal epithelium on a porous membrane; B: intestine-on-a-chip model with intestinal organoids cultured in a microfluidic device, where constant perfusion and periodic mechanical strain can be applied on the system; C: ingestible sensors for measuring various parameters relevant to gut functions.