Apolipoprotein(a) isoforms in infarcted men under 60 years old

Lipoprotein (a) as a cause of cardiovascular disease: insights from epidemiology, genetics, and biology

Human epidemiologic and genetic evidence using the Mendelian randomization approach in large-scale studies now strongly supports that elevated lipoprotein (a) [Lp(a)] is a causal risk factor for cardiovascular disease, that is, for myocardial infarction, atherosclerotic stenosis, and aortic valve stenosis. The Mendelian randomization approach used to infer causality is generally not affected by confounding and reverse causation, the major problems of observational epidemiology. This approach is particularly valuable to study causality of Lp(a), as single genetic variants exist that explain 27-28% of all variation in plasma Lp(a). The most important genetic variant likely is the kringle IV type 2 (KIV-2) copy number variant, as the apo(a) product of this variant influences fibrinolysis and thereby thrombosis, as opposed to the Lp(a) particle per se. We speculate that the physiological role of KIV-2 in Lp(a) could be through wound healing during childbirth, infections, and injury, a role that, in addition, could lead to more blood clots promoting stenosis of arteries and the aortic valve, and myocardial infarction. Randomized placebo-controlled trials of Lp(a) reduction in individuals with very high concentrations to reduce cardiovascular disease are awaited. Recent genetic evidence documents elevated Lp(a) as a cause of myocardial infarction, atherosclerotic stenosis, and aortic valve stenosis.

Lipoprotein (a) and apolipoprotein (a) in primary antiphospholipid syndrome

OBJECTIVE

To investigate whether lipoprotein (a) (Lp(a)) and/or apolipoprotein (a) (apo(a)) may be markers for clinical features of 37 patients with primary antiphospholipid syndrome (PAPS) and to compare with 37 age- and sex-matched controls.

METHODS

Apo(a) and Lp(a) concentrations were determined by ELISA and immunonephelometry, respectively.

RESULTS

Only elevated apo(a) concentrations were significant predictor for cerebrovascular insults (OR=14.399, p=0.005, 95% CI: 2.224-93.230).

CONCLUSION

Considering the fact that PAPS patients with cerebrovascular insults had recurrence of cerebrovascular episodes, measurement of apo(a) concentrations will help in the follow-up of those patients and thus in the prediction of future episodes. This finding should be further investigated in a larger study in order to provide adequate therapeutic intervention.