Plasma levels of lipoprotein-associated phospholipase A2are increased in patients with β-thalassemia

Lipoprotein-associated phospholipase A2(Lp-PLA2) is an independent cardiovascular risk factor. We investigated the plasma levels of Lp-PLA2activity and mass as a function of plasma lipid levels, LDL subclass profile, and oxidative stress in patients with β-thalassemia. Thirty-five patients with β-thalassemia major (β-TM) and 25 patients with β-thalassemia intermedia (β-TI) participated in the study. Lp-PLA2activity and mass were measured in total plasma, in apolipoprotein (apo)B-depleted plasma (HDL-Lp-PLA2), and in LDL subclasses. Lp-PLA2activity produced and secreted from peripheral blood monocytes in culture was also determined. Patients with β-thalassemia are characterized by a predominance of small-dense LDL particles, increased oxidative stress, and very high plasma levels of Lp-PLA2mass and activity, despite low LDL-cholesterol levels. A significant positive correlation between plasma Lp-PLA2activity or mass and 8-isoprostane (8-epiPGF2a) and ferritin levels as well as intima-media thickness (IMT) values was observed. An increase in secreted and cell-associated Lp-PLA2activity from monocytes in culture was observed in both patient groups. The HDL-Lp-PLA2activity and mass as well as the ratio of HDL-Lp-PLA2/plasma Lp-PLA2were significantly higher in both patient groups compared with the control group. In conclusion, patients with β-thalassemia exhibit high plasma Lp-PLA2levels, attributed to increased enzyme secretion from monocytes/macrophages and to the predominance of sdLDL particles in plasma. Plasma Lp-PLA2is correlated with carotid IMT, suggesting that this enzyme may be implicated in premature carotid atherosclerosis observed in β-thalassemia.