Plasma Lp-PLA2 mass and apoB-lipoproteins that carry Lp-PLA2 decrease after sodium

Eur J Clin Invest 2012; 42 (11): 12351243 Abstract Background Lipoprotein-associated phospholipase A2 (Lp-PLA2) is a novel cardiovascular risk marker, which is predominantly complexed to apolipoprotein (apo) B-containing lipoproteins in human plasma. As increasing dietary sodium intake may decrease plasma apoB-containing lipoproteins, we tested whether a sodium challenge lowers plasma Lp-PLA2 mass, as well as the levels of apoB-containing lipoprotein particles carrying Lp-PLA2 (apoB-Lp-PLA2), employing a newly developed enzyme-linked immunosorbent assay. Materials and methods In 45 women and 31 men (mean age 44 +/- 14 years), plasma Lp-PLA2 mass (turbidimetric immunoassay), the level of apoB-Lp-PLA2, expressed in apoB concentration and lipoproteins were measured in response to a 3-day challenge with 9 g sodium chloride tablets daily. Results Urinary sodium excretion increased from 165 +/- 60 to 321 +/- 70 mmol/24 h (P <0.001) after salt loading. Plasma Lp-PLA2 mass decreased from 618 (493719) to 588 (465698) mu g/L (P <0.001), and apoB-Lp-PLA2 decreased from 0.276 (0.2000.351) to 0.256 (0.1890.328) g LDL protein/L (P = 0.004) in response to the sodium challenge together with decreases in plasma total cholesterol, nonhigh-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, apolipoprotein B and the total cholesterol/HDL cholesterol ratio (P <0.01 for all). Changes in plasma Lp-PLA2 mass were correlated positively with changes in total cholesterol, LDL cholesterol and non-HDL cholesterol (r = 0.2600.276, P <0.05 to P <0.02), whereas changes in apoB-Lp-PLA2 were correlated positively with changes in non-HDL cholesterol and in the total cholesterol/HDL cholesterol ratio (r = 0.2320.385, P <0.050.01). Conclusion Both plasma Lp-PLA2 mass levels and apoB-Lp-PLA2 decrease in response to a short-term oral sodium challenge.