Autor: |
Tselepis, Alexandros D., Hahalis, George, Tellis, Constantinos C., Papavasiliou, Eleni C., Mylona, Panagiota T., Kourakli, Alexandra, Alexopoulos, Dimitrios C. |
Zdroj: |
Journal of Lipid Research; November 2010, Vol. 51 Issue: 11 p3331-3341, 11p |
Abstrakt: |
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. |
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