Abstract
BACKGROUND: Increased oxidative stress has been implicated in the pathogenesis of coronary vasospasm. Thioredoxin (TRX) is a redox-active protein that is known to be induced by oxidative stress. HYPOTHESIS: The serum TRX level may be high in patients with coronary vasospasm. METHODS: The serum TRX level was determined using an enzyme-linked immunosorbent assay in 21 patients with the active stage of coronary spastic angina (CSA), in 18 patients with the inactive stage of CSA (iCSA), in 24 control subjects without coronary artery disease (Control), and in 20 patients with stable effort angina (SEA). RESULTS: Serum TRX levels (mean +/- standard deviation ng/ml) were significantly higher in CSA (64 +/- 44) than in iCSA (28 +/- 26), in Control (34 +/- 15), and in SEA (36 +/- 16). In contrast, serum alpha-tocopherol levels (mg/g lipids) were significantly lower in CSA (2.8 +/- 0.7) than in Control (4.0 +/- 1.2) and in SEA (3.2 +/- 0.4). Current smoking was significantly more prevalent in CSA (76%) than in any of the other groups. No significant correlation was found between the serum level of TRX and alpha-tocopherol in the study subjects. In nine patients with CSA, the serum TRX level decreased (93 +/- 41 --> 41 +/- 35 ng/ml) and the alpha-tocopherol level increased (2.7 +/- 0.6 --> 3.2 +/- 0.7 mg/g lipids) significantly under medication with calcium entry blockers after an at least 3-month angina-free period. CONCLUSIONS: Patients with coronary spastic angina had a higher serum TRX level associated with a lower serum level of antioxidant vitamin E, with redox equilibrium appearing to be related to the disease activity of coronary vasospasm in these patients. Oxidative stress may be related to the genesis of coronary vasospasm.