Low SOD activity is associated with overproduction of peroxynitrite and nitric oxide in patients with acute coronary syndrome

• Oxidative/nitrosative status was evaluated as well as antioxidant defence in patients with acute coronary syndrome.
• Increased levels of superoxide, nitric oxide and peroxynitrite and reduced SOD activity were reported in these patients.
• Overproduction of both superoxide and NO resulted in enhanced peroxynitrite levels, leading to modified enzymes structures.
• A possible relation between decreased SOD activity and peroxynitrite formation leads to the plaque rupture.

ObjectiveThe present study was undertaken to evaluate the variation of the oxidative/nitrosative stress status in a population of subjects; with acute coronary syndrome (ACS), and examine its possible implication in plaque rupture which is the main mechanism in the pathophysiology of ACS.Patients and methodsWe made this study on 50 men with ACS and 50 age and sex matched healthy controls. Nitrosative/oxidative stress markers including; nitric oxide, superoxide anion levels, superoxide dismutase (SOD) activity and peroxynitrite levels were evaluated in blood samples of patients and controls.ResultsCompared with healthy subjects, coronary patients had significantly higher nitric oxide, peroxynitrite and superoxide anion concentrations in both plasma and erythrocytes associated to significant decrease of SOD activity. Erythrocytes peroxynitrite concentration was negatively correlated with the antioxidant enzyme activity (SOD).ConclusionOur results show a significant accumulation of both intracellular and plasma pro-oxidants with a concomitant decrease in the SOD scavenging activity in ACS patients. Both seem to be associated with plaque rupture and ischemia observed in ACS.