STRUCTURE AND POSSIBLE BIOLOGICAL ROLES OF LP(A)

Lipoprotein(a) [Lp(a)] is a plasma macromolecular complex that is asse mbled from low-density lipoproteins (LDL) and a large hydrophilic glyc oprotein, named apolipoprotein(a) [apo(a)], linked by a disulfide bond to apolipoprotein B-100. Apo(a) is formed by different structural dom ains one of which is present in multiple copies, the number of which i s determined by variation in the hypervariable apo(a) gene. Sequence h omology of apo(a) with plasminogen may explain the competition of Lp(a ) for some physiological functions of plasminogen in the coagulation a nd fibrinolytic cascade in vitro. There is evidence that high plasma l evels of Lp(a) may have atherogenic and/or thrombogenic potential. Mor e work will have to be done to understand the exact role of Lp(a) in a therogenesis, to evaluate the potential synergy between Lp(a) and LDL in promoting coronary artery disease, and to assess the therapeutic be nefits of a reduction of Lp(a) levels.