Effect of SB CD on Chylomicron

It is often suggested that lymphatic vessels are ineffective in transporting cargo in Crohn's disease. Our own work on surgically resected tissue supports this concept (1), but the concept has not been directly tested. Chylomicrons are packaged lipids from the diet with an obligatory absorption route through the lymphatic vasculature to reach host plasma. This protocol takes an approach to directly quantify chylomicron secretion using a fatty meal that incorporates stable isotopic tracers for trioleate and cholesterol in the meal. We will collect baseline plasma and then plasma every 30 minutes for 5.5 hours to chart the kinetic and magnitude of chylomicron secretion and transport in all subjects using mass spectrometry analysis. We will characterize a wide variety of parameters on the chylomicrons as well using ELISA. Infusions i.v. of stable isotope labeled triglyceride and glycerol will allow us to consider whether there are changes in VLDL metabolism that could account for differences in chylomicron handling once the chylomicrons are secreted into plasma. Collection and analysis of breath samples will also be carried to normalize against possible incomplete lipid absorption in some subjects.