Lipoproteina (a). Sua importância como marcador adicional de aterosclerose.

Resumo

Lipoprotein(a) is one of the best examples of heterogeneity of lipoproteins. It presents pre-beta electrophoretic mobility in agarose gel, similar to Very Low Density Lipoproteins, it is found in High Density Lipoproteins due to its hydrated density greater than 1,063 and resembles Low Density Lipoproteins in its size and lipid composition. However, Lp(a) is unique in that it contains an additional distinct antigen, the apo(a), attached to apoB100 by one disulphide bridge. The apo(a)-glycoprotein has recently been shown to have a striking amino acid sequence homology with plasminogen; Lp(a) seems to be a potential bridge between atherosclerosis and thrombosis fields and interest in Lp(a) has greatly increased since then. The new knowledge on the structure of Lp(a) being more and more rapidly acquired should facilitate our understanding of the mechanisms of its atherogenicity and its physiopathological role. Metabolic studies have made it clear that Lp(a) is not a product derived from other apoB-containing lipoproteins, but is secreted by the liver as a distinct mature lipoprotein. Concerning the immunological techniques available to assay Lp(a) they need to be standardized and it is still necessary to define what is meant by the pathological threshold for Lp(a), which will certainly depend on the choice of the standard antiserum and immunological method used.