The significance of human platelet-activating factor-acetylhydrolase in patients with chronic stable angina

Lipoprotein-associated phospholipase A2 prognostic role in atherosclerotic complications

Atherosclerosis manifests itself clinically at advanced stages when plaques undergo hemorrhage and/or rupture with superimposed thrombosis, thus abruptly stopping blood supply. Identification of markers of plaque destabilization at a pre-clinical stage is, therefore, a major goal of cardiovascular research. Promising results along this line were provided by studies investigating the lipoprotein-associated phospholipase A2 (Lp-PLA2), a member of phospholipase A2 proteins family that plays a key role in the metabolism of pro-inflammatory phospholipids, as oxidized low-density lipoproteins, and in the generation of pro-atherogenic metabolites, including lysophosphatidylcholine and oxidized free fatty acids. We herein review the experimental and clinical studies supporting use of Lp-PLA2 activity for predicting cardiovascular events. To his end we considered not only Lp-PLA2 activity and mass, but also Lp-PLA2 gene variations and their association with incident coronary artery disease, stroke, and cardiovascular mortality. Based on these evidences the major scientific societies have included in their guidelines the measurement of Lp-PLA2 activity among the biomarkers that are useful in risk stratification of adult asymptomatic patients at intermediate cardiovascular risk. The results of two recently published major clinical trials with the Lp-PLA2 inhibitor darapladib, which seem to challenge the pathogenic role of Lp-PLA2, will also be discussed.

Low basal levels of circulating adiponectin in patients undergoing coronary stenting predict in-stent restenosis, independently of basal levels of inflammatory markers: lipoprotein associated phospholipase A2, and myeloperoxidase

OBJECTIVE

The aim of this study was to find a pre-interventional marker with the capacity to predict in-stent restenosis (ISR). Considering the anti-atherosclerotic role of adiponectin (APO), an adipocytokine with anti-inflammatory, anti-proliferative, anti-oxidative and anti-thrombotic properties, low plasma levels of APO might be correlated with the risk of ISR. We investigated the correlations between the plasma levels of APO and two markers of inflammation: lipoprotein associated phospholipase A2 (Lp-PLA2) and myeloperoxidase (MPO).

DESIGN AND METHODS

80 patients with angiographically significant stenosis underwent percutaneous coronary intervention (PCI) with bare metal stent. Plasma APO concentration and plasma Lp-PLA2 and MPO activities were evaluated immediately before and after PCI, then followed-up at 24, 48, 72 h, and at 1, 3, 6 months, respectively. ISR was evaluated at 6 months after stenting by follow-up coronary angiograms, and it was defined as >50% stenosis of the target lesion.

RESULTS

ISR was present in 33.75% of patients. Baseline APO plasma concentration, measured before PCI, was lower in ISR patients than those without ISR [3.97 (+/-1.05) vs 6.65 (+/-2.95) microg/mL respectively, p<0.001]. The patients with APO values less than 4.9 microg/mL at discharge were more susceptible to develop ISR (odd ratio, 4.27; 95% CI, 1.56-11.72, p<0.001). ISR rate was independent of inflammation markers Lp-PLA2 and MPO baseline values, measured before PCI.

CONCLUSIONS

The persistence of a low APO plasma level at discharge and 6 months afterwards may be used as a clinically useful marker for ISR prediction in patients undergoing PCI.

Plasma markers of endothelial dysfunction in type 2 diabetics

BACKGROUND

Type 2 diabetes, or non-insulin-dependent diabetes mellitus, represents an independent risk factor for cardiovascular diseases (CVD), being characterized by a continuous low-grade inflammation and endothelial activation state. Atherosclerotic lesions occur in diabetic patients at an earlier age with severe clinical manifestations and poor outcome. Our objective was to investigate the correlation between lipoprotein-associated phospholipase A2 (PLA2-LDL), myeloperoxidase (MPO), and paraoxonase (PON), enzymes implicated in the evolution of endothelial dysfunction associated with type 2 diabetes.

METHODS

One hundred diabetic patients [50 without documented coronary artery disease (group 1) and 50 with CVD (group 2)] and 46 healthy controls were investigated for PLA2-LDL, MPO, and PON activities.

RESULTS

PLA2-LDL activity was significantly higher in group 2 than in group 1 and among controls. PON activity was lower in group 1 than in controls, reaching the lowest level in group 2. MPO activity was higher in type 2 diabetics than among controls, with similar values in groups 1 and 2.

CONCLUSIONS

The evaluation of PLA2-LDL, MPO, and PON activities may improve early diagnosis of CVD in asymptomatic patients with type 2 diabetes and can help to evaluate accelerated atherosclerosis and microvascular disease.