The Isolation of Flowing Mesenteric Lymph in Mice to Quantify <em>In Vivo</em> Kinetics of Dietary Lipid Absorption and Chylomicron Secretion

Intestinal lipoproteins, especially triglyceride-rich chylomicrons, are a major driver of metabolism, inflammation, and cardiovascular diseases. However, isolating intestinal lipoproteins is very difficult in vivo because they first secreted from the small intestine into mesenteric lymphatics. Chylomicron-containing lymph then empties subclavian vein thoracic duct to deliver components meal heart, lungs, and, ultimately, whole-body circulation. Isolating naïve chylomicrons impossible blood since chylomicron triglyceride undergoes hydrolysis immediately upon interaction with lipoprotein lipase other receptors Therefore, original 2-day fistula procedure, described by Bollman et al. rats, has historically been used isolate fresh before its entry vein. That protocol improved professionalized laboratory Patrick Tso for last 45 years, allowing analysis these critical secretions gut. The procedure now updated presented here visually time. This revised single-day surgical technique installing duodenal feeding tube, cannulating duct, collecting after conscious mice. benefits new techniques include ability reproducibly collect mice (which harnesses power genetic mouse models); reduced anesthesia time during implantation infusion tube cannula; continuously sample throughout post-prandial period; quantitatively measure hormones cytokines their dilution enzymatic blood; large quantities lipoproteins. powerful tool directly measuring dietary nutrient absorption, synthesis, secretion.