Obesity and the Digestive System
Patrick Tso, PhD
Professor
Department of Pathology and Laboratory Medicine
Description of Research
Dr. Tso studies the mechanisms and factors regulating the assembly and secretion of chylomicrons and very low-density lipoproteins by the small intestine. Recently, he demonstrated that the secretion of apolipoprotein B into lymph by the small intestine was unaltered by acute feeding of triglyceride. Since each triglyceride-rich lipoprotein contains one copy of apolipoprotein B, it would imply that the number of triglyceride-rich lipoproteins made by the small intestine is not altered during active lipid absorption. Rather, the triglyceride-rich lipoproteins simply enlarge to accommodate the excess triglycerides. He also demonstrated that the reason why the gut makes a smaller version of apolipoprotein B (B-48 instead of B-100 in the liver) is because it is more efficient in facilitating the transport of triglyceride as chylomicrons by the enterocytes. Additionally, Dr. Tso has demonstrated that increased apolipoprotein A-IV in chylous lymph is an important factor involved in anorexia after fat feeding. This finding demonstrates for the first time a physiological function of apolipoprotein A-IV that is not shared by apolipoprotein A-I. He is actively pursuing both the site of action of apolipoprotein A-IV and the active site of the apolipoprotein A-IV molecule. Recently, his laboratory has become interested in the activation of mucosal mast cells by fat absorption.
Collaborations
Dr. Tso collaborates with Drs. Aronow and Hui on apolipoprotein and cholesterol absorption. He also works with Dr. Heubi investigating the effects of intraluminal bile acid concentrations on cholesterol absorption. Anticipated Core use: Integrative Morphology Core.
