Lipoprotein(a) and the risk of thromboembolism in Thai children

Lp(a) does not affect intima media thickness in hypercholesterolemic children -a retrospective cross sectional study

PURPOSE

Combined hyperlipidaemia results in premature atherosclerosis and a high burden of cardiovascular morbidity and mortality. Early identification of highly affected subjects within this population is of utmost importance to enable informed treatment decisions. The measurement of intima media thickness (IMT) is a readily available, non-invasive method to investigate evidence of early atherosclerosis. To assess the usefulness of this method in pediatric subjects with hypercholesterolemia, we here examined a possible interaction of LDL-C and Lp(a) on IMT.

METHODS

Blood lipids (Lp(a), LDL-cholesterol, total cholesterol, triglycerides, high density lipoprotein (HDL) -cholesterol, apolipoprotein A1, apolipoprotein B), anthropometric parameters (age, height, weight, body mass index (BMI)) and possibly existing early evidence of atherosclerotic lesions measured by intima media thickness (IMT zscore).as a surrogate parameter was examined retrospectively in 113 children and adolescents (aged 1-18 years) with elevated Lp(a) and/or LDL-cholesterol (Lp(a) > 30 mg/dL, LDL>130 mg/dL). Furthermore, we compared hsCRP levels between groups.

RESULTS

There were no significant differences in IMT Zscore or hsCRP between groups. Regression analysis did not reveal a statistically significant interaction between Lp(a) and LDL-C.

CONCLUSIONS

At the age of 6-18 years, we found no significant differences in early markers of atherosclerosis between subjects with high Lp(a)- and/or high LDL-cholesterol with no detectable synergistic effects between the two lipoproteins.

Lipoprotein (a): truly a direct prothrombotic factor in cardiovascular disease?

Elevated plasma concentrations of lipoprotein (a) [Lp(a)] have been determined to be a causal risk factor for coronary heart disease, and may similarly play a role in other atherothrombotic disorders. Lp(a) consists of a lipoprotein moiety indistinguishable from LDL, as well as the plasminogen-related glycoprotein, apo(a). Therefore, the pathogenic role for Lp(a) has traditionally been considered to reflect a dual function of its similarity to LDL, causing atherosclerosis, and its similarity to plasminogen, causing thrombosis through inhibition of fibrinolysis. This postulate remains highly speculative, however, because it has been difficult to separate the prothrombotic/antifibrinolytic functions of Lp(a) from its proatherosclerotic functions. This review surveys the current landscape surrounding these issues: the biochemical basis for procoagulant and antifibrinolytic effects of Lp(a) is summarized and the evidence addressing the role of Lp(a) in both arterial and venous thrombosis is discussed. While elevated Lp(a) appears to be primarily predisposing to thrombotic events in the arterial tree, the fact that most of these are precipitated by underlying atherosclerosis continues to confound our understanding of the true pathogenic roles of Lp(a) and, therefore, the most appropriate therapeutic target through which to mitigate the harmful effects of this lipoprotein.