Elevated plasma platelet-activating factor acetylhydrolase activity and its relationship to the presence of coronary artery disease*

BACKGROUND: Platelet-activating factor acetylhydrolase (PAF-AH) is a circulating enzyme that has an important role in the development of coronary artery disease (CAD). The correlations between PAF-AH and CAD are controversial. Furthermore, the differences of the enzyme levels between patients with stable and unstable CAD are not fully determined. The purpose of this study was to evaluate plasma PAF-AH levels and its association with the presence of CAD and some clinical risk factors in the patients. METHODS: This case-control study included 50 control subjects without CAD, 50 stable CAD patients and 50 unstable CAD patients with angiographically documented CAD. Plasma PAF-AH activity was determined by a commercial kit. The inflammatory markers, high sensitivity C-reactive protein (hsCRP) and oxidized low density lipoprotein (ox-LDL), and lipid profile were also measured. Comparisons of biochemical risk factors among all groups were performed by one way ANOVA. The association of PAF-AH activity with the presence of CAD was analyzed by multiple logistic regression. RESULTS: Plasma PAF-AH activity levels were higher in unstable CAD patients (0.040 ± 0.012 μmol/min/ml) than in stable CAD patients (0.032 ± 0.010 μmol/min/ml) and control subjects (0.026 ± 0.009 μmol/min/ml) (p < 0.01). Plasma PAF-AH activity was also independently associated with the presence of CAD (p< 0.01). CONCLUSIONS: Plasma PAF-AH activity levels were highly increased in unstable and stable CAD patients as compared to control subjects and may be a useful biomarker for CAD prediction.