A recent study published in the journal Nutrients provides a comprehensive review of the lipoprotein pathway in healthy metabolism. Study: Effects of lipoproteins on metabolic health. Image Credit: Nemes Laszlo / Shutterstock.
com Lipoproteins consist of lipids that are chemically attached to protein conjugates called apolipoproteins. These amphipathic molecules have a central lipid core of cholesterol esters and triacylglycerol within a double membrane of phospholipids and free cholesterol conjugated to apolipoproteins. Some examples of lipoproteins include high-density lipoprotein (HDL), low-density lipoprotein (LDL), very low-density lipoprotein (VLDL), and lipoprotein(a) (LP[a]), with the density of these molecules inversely related to their size.
HDL and LDL are the smallest lipoproteins at eight to 12 nanometers (nm) and 18-25 nm, respectively, whereas chylomicrons are the largest at 100-1200 nm. Dietary lipids are digested within the gastrointestinal tract, following which they enter the intestinal mucosa to become chylomicrons, transporting triacylglycerols from food into the blood. Chylomicron breakdown in muscle or fat tissue yields chylomicron remnants for excretion by liver cells.
Lipoprotein synthesis occurs in the liver and begins with the production of VLDL, which contains triglycerides. After further processing, these triglycerides become intermediate-density lipoproteins (IDL) and, subsequently, LDL or LP(a). VLDL transports triacylglycerols produced by the bo.
