Category: Lipoproteins: Very low-density, Low-density, Intermediate-density, High-density, & Chylomicrons

Download Slides What are Lipoproteins? Lipoproteins are roughly spherical particles with a lipid core composed mainly of triglycerides, cholesterol ester, and a surface layer containing phospholipid, cholesterol, and protein [11]. When lipids (cholesterol, triglycerides) are absorbed by intestinal cells after a meal, they travel in the bloodstream as constituents of lipoproteins due to their poor…

Lipoproteins are composed of an outer water-soluble surface and an inner water-insoluble core. The outer portion comprises of phospholipids, protein, and cholesterol, with triglycerides and cholesterol ester forming the core. The specific proteins associated with lipoproteins are called apolipoproteins (five major classes, A-E). The surface proteins enable the lipoproteins to interact with other membranes such…

Lipoproteins arise from enterocytes in the intestine, forming chylomicrons, and from hepatocytes in the liver, forming, VLDL, HDL, and IDL. The assembly of chylomicrons within the enterocyte and the subsequent secretion of these lipoprotein particles into the lymph is a complex, multi-step process that includes [4]: The absorption of lipids by the enterocytes [Dietary fats…

Lipoproteins are usually classified by their densities. The density increases as the protein content increases. Recall that the protein content mainly refers to the proteins embedded in the plasma membrane, the apolipoproteins. This is what allows the lipoprotein to be soluble in the water content of the blood. There are five major types, each of…

Exogenous Pathway Lipids are digested. Chylomicrons are assembled with apolipoprotein B-48. Chylomicrons move into the liver and subsequently into the bloodstream, where HDL donates apolipoprotein C-II and E, forming a mature chylomicron. ApoC can only bind to receptors found on adipose tissue while ApoE can only bind to receptors on hepatocytes. Mature chylomicrons activate lipoprotein…

Small, dense LDL has several characteristics that are linked to atherogenesis (plaque in the inner lining of arteries) [6]: Long residence time in plasma Enhanced oxidizability Arterial proteoglycan binding [binds to protein-sugar molecules in the arteries] Permeability through the endothelial barrier The only protein associated with LDL is ApoB100; LDL’s do not possess ApoC or…

Regular physical exercise is a deterrent of cardiovascular disease and its anti-atherogenic effects have been described in human studies [1]. On the contrary, physical inactivity has adverse consequences on cardiovascular risk, due in part to detrimental effects of serum lipoprotein concentration, namely LDL [3]. To investigate the effects of the amount and intensity of exercise…

To date, the only ‘potential’ known mechanism documented was based on studies performed on mice (Mus musculus). Like humans, mice possess a similar mode of lipid metabolism and respond to exercise in a similar fashion; that is, the greater the exercise’s intensity, the greater the response [8]. Mice also possess identical lipoprotein receptors found in…

Although damage to arteries and blood vessels cannot be reversed, exercising regularly will reduce further damage by reducing LDL and increasing HDL cholesterol. The less LDL in the bloodstream, the less there is available to trigger or promote the artery-clogging process known as atherosclerosis. Foods low in saturated fat (lipids that are solid at room temperature, such…