Correlation between plasma malonyldialdeide levels and paroxonase activity in healthy subjects and in patients with atherosclerotic disease

Paraoxonase (PON) is a calcium-dependent HDL-associated ester hydrolase catalizying hydrolysis of organophosphates. Its biological role is still unknown: experimental studies suggest a hydroperoxidasic activity on lipoperoxides formed during LDL-oxidation, thus acting as a protective agent against atherogenesis. We evaluated PON activity in healthy subjects (HS) and in patients with cardiovascular (CHD) and cerebrovascular (CVD) disease ; PON activity was correlated with plasma malonyldialdeide (MDA) levels, as markers of lipid peroxidation Materials and Methods: 33 HS (age 7012 yr), 45 CHD (age 818 yr) and 38 CVD (age 8011 yr) patients were studied. Serum PON and plasma MDA levels were measured spectrophotometrically. Statististical analysis was performed by ANOVA univariate for groups comparation and by Pearson r test for values correlation Results: PON activity (mol min-1 ml-1) is higher in HS (0.0750.03) than in CHD (0.0450.03) and CVD (0.0560.03) patients (p<0.05 HS vs. CHD and CVD; ns CHD vs. CVD). MDA (mol/ml) levels are lower in HS (0.0280.023) than in CHD (0.0630.012) and in CVD (0.0560.036) patients (p<0.05 in HS vs. CHD and CVD, ns in CHD vs CVD). Table shows correlation between PON activity and MDA plasma levels in the three studied groups are shown below. rsignificanceHS-.43 p<0.05CHD-.39 p<0.01CVD-.33 p<0.05Conclusions: PON activity is significatively higher in HS than in CHD and CVD patients; whereas there are no significant difference between CHD e CVD patients. In all groups there is statistically significant negative correlation between PON activity and lipid peroxides content (MDA levels) in plasma. Our results suggest a protective role of PON activity against atherogenesis occurring with higher levels of lipoperoxides.