Lipoprotein abnormalities associated with alzheimer's disease, Essay

Lipoprotein abnormalities associated with alzheimer's disease, diabetes, atherosclorosis - Essay Example The human plasma lipoproteins are commonly classified into six major classes. Chylomicrons form the largest proteins approximately >100nm in diameter. They are synthesized within the intestines and transport dietary triglyceride and cholesterol from absorption sites to various cells of the body. The triglycerides of these particles are hydrolyzed within the plasma compartment through catalysis by lipoprotein lipase. Fatty acids generated through the breakdown are used as a source of energy by the various cells or are taken up by adipocytes (Zhang, Song, Cavigiolio, Ishida, Zhang, Kane, Weisgraber, Oda, Rye, Pownall & Ren, 2011). Lipoprotein particles generated through the action of lipoprotein lipase on Chylomicrons are called chylomicron remnants. The other category of lipoproteins is the very low density lipoproteins (VLDL, with a density of less than 1.006g/ml and a diameter ranging between 30-90nm. These particles transport triglycerides and cholesterol from the liver for re-dist ribution to other tissues in the body. In the plasma compartment, the triglycerides of the VLDL undergo hydrolysis through lipoprotein lipase. This reaction results into the generation of smaller, cholesterol-enriched lipoproteins including intermediate density lipoproteins (IDL). ... High density lipoproteins (HDL) have a density of between 1.063-1.21g/ml, and appear to arise from numerous sources including the intestine and liver. These particles are the smallest of all the lipoproteins which are involved in a process called reverse cholesterol transport. This is a hypothesized pathway whereby HDL acquires cholesterol from peripheral tissues and transports the cholesterol directly or indirectly to the liver (Mahley, Innerarity, Rall & Weisgraber, 2008). The apolipoprotein components of the major plasma lipoproteins can be visualized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Apolipoproteins of the numerous lipoproteins modulate the metabolism of lipoproteins and determine the unique roles of these lipoproteins in lipid metabolism. A well established function of the apolipoprotein is their involvement in the transport and re-distribution of lipids within several tissues (Mahley, Innerarity, Rall & Weisgraber, 2008). The delivery of lipids to sp ecific to specific cells and tissues involves the recognition of specific apolipoproteins by cell surface lipoprotein receptors. Another function of apolipoproteins involves their role as cofactors for enzymes of lipid metabolism. Another function for specific apolipoproteins involves their role in the maintenance of the structure of lipoproteins. Numerous apolipoproteins including apoB, apoA-I and apoE appear to stabilize the micellar structure of the lipoproteins. In addition, these apolipoproteins together with phospholipids on the surfaces of the particles provide a hydrophilic surface. Apolipoprotein E is a component of the chylomicrons, VLDL, chylomicron