Objectives: Inflammation, a major risk factor for acute myocardial infarction (AMI), is associated with leukocytic activation, secretion of myeloperoxidase (MPO) and generation of the oxidative damage marker, 3-chlorotyrosine (3-Cl-Tyr). To study their association with AMI and their value in diagnosis of AMI, white blood cell (WBC) count, plasma MPO, plasma 3-Cl-Tyr, and conventional risk factors such as cardiac troponin I and CK-MB were examined in AMI patients during the onset of chest pain.
Methods: After obtaining informed consent, blood samples were collected from 77 AMI patients during the onset of chest pain and from 53 normal controls. The samples were analyzed for WBC count using SE-9000 automated analyzer. Plasma MPO was measured by an enzyme-linked immunosorbent assay. Plasma levels of 3-Cl-Tyr, a product of MPO, were analyzed by HPLC coupled with Coularray electrochemical detection.
Results: The WBC, plasma MPO and 3-Cl-Tyr levels were significantly elevated in AMI patients than in normal controls (p<0.001). The levels of WBC, MPO and 3-Cl-Tyr alone were strongly associated with the prevalence of AMI. Plasma MPO was correlated with 3-Cl-Tyr (r=0.389, p<0.01) and WBC counts (r=0.405, p<0.01) respectively. The ROC curve analyses suggested that MPO had the best specificity and sensitivity among these oxidative stress-related markers.
Conclusion: Plasma MPO value should be considered as a better marker for early diagnosis of AMI, as compared with WBC count or 3-Cl-Tyr.