Plasma levels of lipoprotein-associated phospholipase A(2) are increased in patients with β-thalassemia.
Lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) is an independent cardiovascular risk factor. We investigated the plasma levels of Lp-PLA(2) activity 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-PLA(2) activity and mass were measured in total plasma, in apolipoprotein (apo)B-depleted plasma (HDL-Lp-PLA(2)), and in LDL subclasses. Lp-PLA(2) activity 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-PLA(2) mass and activity, despite low LDL-cholesterol levels. A significant positive correlation between plasma Lp-PLA(2) activity 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-PLA(2) activity from monocytes in culture was observed in both patient groups. The HDL-Lp-PLA(2) activity and mass as well as the ratio of HDL-Lp-PLA(2)/plasma Lp-PLA(2) were significantly higher in both patient groups compared with the control group. In conclusion, patients with β-thalassemia exhibit high plasma Lp-PLA(2) levels, attributed to increased enzyme secretion from monocytes/macrophages and to the predominance of sdLDL particles in plasma. Plasma Lp-PLA(2) is correlated with carotid IMT, suggesting that this enzyme may be implicated in premature carotid atherosclerosis observed in β-thalassemia.
Tselepis
Alexandros D
AD
Department of Chemistry, University of Ioannina, Ioannina, Greece. atselep@uoi.gr
Hahalis
George
G
Tellis
Constantinos C
CC
Papavasiliou
Eleni C
EC
Mylona
Panagiota T
PT
Kourakli
Alexandra
A
Alexopoulos
Dimitrios C
DC
D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase / Q000097:blood* / Q000378:metabolism*; D000328:Adult; D001055:Apolipoproteins B / Q000097:blood; D043303:Aryldialkylphosphatase / Q000097:blood; D001792:Blood Platelets / Q000378:metabolism; D002448:Cell Adhesion; D015237:Dinoprost / Q000031:analogs & derivatives / Q000097:blood; D005260:Female; D006801:Humans; D008077:Lipoproteins, LDL / Q000097:blood; D008297:Male; D009000:Monocytes / Q000378:metabolism / Q000473:pathology; D018384:Oxidative Stress; D017086:beta-Thalassemia / Q000097:blood* / Q000201:enzymology* / Q000378:metabolism / Q000473:pathology
D001055:Apolipoproteins B; D008077:Lipoproteins, LDL; C075750:8-epi-prostaglandin F2alpha; D015237:Dinoprost; D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase; D043303:Aryldialkylphosphatase