Significance of the antioxidant factor,thioredoxin, in heart failure

OBJECTIVES: Increases in oxidative stress may be involved in the progression of heart diseases. However, the serum levels of thioredoxin, a redox regulating protein, have been poorly investigated in patients with heart diseases. This study evaluated the clinical significance of the serum thioredoxin levels in patients with heart failure. METHODS: The serum thioredoxin levels were determined with a sandwich enzyme-linked immunosorbent assay in a total of 34 patients with dilated cardiomyopathy (n = 5), acute coronary syndrome (n = 7), and stable angina (n = 18), including effort angina (n = 7) and vasospastic angina (n = 11), and control subjects (n = 4). RESULTS: The serum thioredoxin levels were significantly elevated in patients with acute coronary syndrome (30.6 +/- 4.9 ng/ml, p < 0.001) and dilated cardiomyopathy (36.9 +/- 8.6 ng/ml, p < 0.001), but not in patients with stable angina (16.8 +/- 5.7 ng/ml, p = 0.27) compared with the control subjects (n = 4, 13.0 +/- 4.9 ng/ml). The serum thioredoxin level in patients with III and IV functional classes of the New York Heart Association (n = 8, 33.3 +/- 8.6 ng/ml, p < 0.001) was significantly higher than in the control subjects. In addition, the serum thioredoxin levels were negatively correlated with left ventricular ejection fractions of the patients (r = 0.59, p < 0.001). CONCLUSIONS: These results indicate a possible association between thioredoxin and the severity of heart failure.