on October 1, 2009
Published online before print October 1, 2009, doi: 10.1161/ATVBAHA.109.196592
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Submitted on May 16, 2008
Accepted on September 22, 2009
Increased PAFAH and Oxidized Lipids Are Associated With Inflammation and Atherosclerosis in Hypercholesterolemic Pigs
Dieuwke De Keyzer ;
From the Atherosclerosis and Metabolism Unit, Department of Cardiovascular Diseases (D.D.K., B.G., P.H.), Katholieke Universiteit Leuven, Belgium; INSERM UMRS937 (S.A.K., W.W., D.S., E.N.), Université Pierre et Marie Curie UPMC-Paris 6 and Faculté de Médecine Pierre et Marie Curie, Paris, France; and Centre de Recerca Biomèdica (J.M., J.C.), Hospital Universitari de Sant Joan, Catalunya, Spain.
* To whom correspondence should be addressed. E-mail: paul.holvoet{at}med.kuleuven.be.
Objective—To study the association of PAF-acetyl hydrolase (PAFAH) activity with inflammation, oxidative stress, and atherosclerosis in hypercholesterolemic swine.
Methods and Results—Cholesterol-rich diet feeding of miniature pigs was associated with an increase in PAFAH activity and an increase of the PAFAH to PON1 ratio. PLA2G7 RNA (coding for PAFAH) expression was increased in blood monocytes and plaque macrophages. Increased PAFAH activity was associated with higher plasma lysophosphatidylcholine and correlated with oxidized LDL. In THP1 monocytes and macrophages and in human blood-derived macrophages, oxidized LDL induced PLA2G7 RNA expression. Atherogenic diet feeding induced the accumulation of macrophages and oxidized LDL in the arterial wall leading to atherosclerosis. PAFAH activity correlated positively with plaque size and TNFalpha expression in plaque macrophages.
Conclusions—We demonstrated that an increase in PAFAH activity was associated with increased levels of lysophosphatidylcholine, oxidized LDL, and inflammation, resulting in accelerated atherosclerosis in hypercholesterolemic minipigs. The significant correlation between PLA2G7 RNA expression in plaque macrophages and plasma PAFAH activity suggest that the latter is a consequence, rather than a cause of macrophage accumulation. Our cell experiments suggest that oxidized LDL can induce PAFAH, resulting in accumulation of lysophosphatidylcholine that increases the inflammatory action of oxidized LDL.
Key words: atherosclerosis • oxidative stress • inflammation • PAFAH • genes