Relationship among plasma secretory phospholipase A2, oxidized low density lipoprotein & paraoxonase activities in hypertensive subjects treated with angiotensin converting enzyme inhibitors.

BACKGROUND & OBJECTIVE: Secretory phospholipase A(2) (sPLA(2)) and oxidized low density lipoprotein (oxLDL) are considered as oxidative and inflammatory markers. The effects of oxLDL have been shown to be inhibited by paraoxonase (PON1). This study was undertaken to investigate the relationship between oxidative and inflammatory markers in hypertensive patients with or without antihypertensive drug treatment. METHODS: Newly diagnosed hypertensive patients (n=35) and hypertensive patients who had been taking angiotensin converting enzyme (ACE) inhibitors as antihypertensive therapy (10 or 20 mg/day for 9 +/- 2 wk; n=35) and age-matched normotensive subjects (controls; n=20) were included in this study. Plasma sPLA(2), oxLDL and PON1 activities were determined. RESULTS: Hypertensives had higher plasma oxLDL and sPLA(2) levels (P<0.01) and lower PON1 levels than the controls (P<0.01). Treated hypertensives had lower plasma sPLA< and oxLDL levels and higher PON1 activities than hypertensives (P<0.01). sPLA(2) was positively correlated with oxLDL (r=0.433, P<0.01) and negatively correlated with plasma PON1 (r=-0.540, P<0.01) in untreated hypertensives. In controls and treated hypertensives, plasma PON1 was positively correlated with oxLDL (r=0.455, r=0.429, P<0.01, respectively) and sPLA(2) (r=0.450, r=0.506, P<0.01, respectively). INTERPRETATION & CONCLUSION: Reduction in PON1 activity and elevation in both sPLA(2) activities and oxLDL levels might be involved in elevated oxidative stress and inflammation. ACE inhibitor treatment may help reduce inflammation and oxidative stress in hypertensives.