Oxidative stress is thought to play important role in cardiovascular disease. Thioredoxin is an important biomarker for determining the degree of oxidative stress. However, the relationship between the plasma thioredoxin levels and myocardial damage has not been investigated.

We measured the plasma thioredoxin levels in the patients suffering with acute myocardial infarction and who also underwent successful primary angioplasty. We then compared the plasma thioredoxin levels and the clinical parameters in acute myocardial infarction patients (n=37) in order to examine the relationship between oxidative stress and myocardial damage.

The plasma thioredoxin level was significantly related with the initial WBC count (r=0.349, p<0.05) and the myocardial damage, the peak CK level (r=0.489, p<0.01), the CK increment (r=0.452, p<0.05), the peak MB level (r=0.417, p<0.05), and the MB increment (r=0.364, p<0.05). We divided the patients into two groups according to the plasma thioredoxin levels. There was a significant difference in myocardial damage between the low and high plasma thoiredoxin levels at the initial WBC count (10174.2±3380.4/uL vs 13500±3740.7/uL, respectively; p<0.01) and the cardiac enzyme, the peak CK level (2565.2±1389.9 IU/L vs 4045.9±1978.9 IU/L, respectively; p=0.02), the CK increment (2309.6±1351.8 IU/L vs 3762.8±2079.7 IU/L, respectively; p=0.03), the peak MB level (208.7±127.5 IU/L vs 322.7±146.3 IU/L, respectively; p=0.02), and the MB increment (173.8±128.4 IU/L vs 277.7±158.9 IU/L, respectively; p=0.05).

High thioredoxin levels were associated with the degree of oxidative stress and the extent of myocardial damage. Thioredoxin levels may be used as a new surrogate biomarker for the severity of oxidative stress and the extent of myocardial damage in the patients suffering with acute myocardial infarction.