Antioxidant enzyme activity in human abdominal aortic aneurysmal and occlusive disease

The present study further investigates evidence for lipid peroxidation in a therosclerotic aortic tissue by determining the activity of antioxidant enz ymes and concentrations of lipid peroxide fluorochromes in abdominal aortas from 15 patients with abdominal aortic aneurysms (AAA), an additional 7 pa tients with ruptured abdominal aneurysms, and 12 patients with atherosclero tic occlusive disease (AOD). Aortas from nonatherosclerotic organ donors se rved as nondiseased controls. Cu,Zn-superoxide dismutase (Cu,Zn-SOD) activi ties in AAA and AOD tissues were 16% and 25% of control activity, respectiv ely. Mn-SOD activity in diseased aortae were about 65% of controls. CuZn-SO D protein in AAA and AOD was 56% and 100% of controls, respectively, result ing in significantly lower CuZn-SOD specific activity in these tissues. Rup tured AAA tissue also had low SOD activity and protein. Glutathione peroxid ase (GPx) activity in AAA and AOD aortas was 70% and 65% of controls, respe ctively, and glutathione reductase (GR) activity in AAA and AOD aortas was 80% and 65% of control activities, respectively. These results were associa ted with significantly higher lipid peroxide fluorochromes, expressed as U/ g aorta, in both groups of atherosclerotic aortas than in controls. AOD aor tas had 33% higher fluorescence than AAA aortas, but the highest levels wer e seen in ruptured AAA. These data further support the involvement of free radicals and lipid peroxidation in atherosclerotic aortic disease, but do n ot indicate that these mechanisms are specifically involved in aneurysm for mation versus development of occlusive disease.