Oxidation of low density lipoprotein (LDL) particles plays a key role in the etiology of atherosclerosis and coronary artery disease (CAD). Oxidative stress enhances the likelihood of LDL oxidation and atherosclerotic plaque development. Paraoxonase (PON1) is an enzyme associated with HDL that metabolizes organophosphates and has antioxidant activity.
In order to investigate the relationship between oxidative stress and the onset of coronary artery disease (CAD), total ferric reducing antioxidant power (FRAP)-as an index of antioxidant capacity of plasma- and the activity of PON 1 were measured in 80 patients over 65 and 80 patients less than 55 years old as late and early-onset CAD groups respectively. Plasma lipids were also determined.
Patients with early-onset CAD had significantly lower serum levels of HDL-C (p<0.05) and higher LDL-C/HDL-C (p<0.01) than the late-onset group. This may imply the significance of HDL at the onset of CAD. There was no difference in serum levels of TG, TC, LDL-C, PON 1 activity and FRAP values between the two groups. The FRAP value was significantly lower than the reference range for healthy subjects in our laboratory. Although the FRAP value is lower in normal elderly people compared to the younger subjects, there was no difference between the two groups. This indicates that in young CAD patients, oxidative stress may be more important than in the elderly subjects and should be monitored in conjunction with routine lipid measurements.
