Serum Thioredoxin and .ALPHA.-Tocopherol Concentrations in Patients With Major Risk Factors

BACKGROUND: Oxidative stress, which is thought to be increased in subjects with various coronary risk factors, induces thioredoxin (TRX), a redox-active protein. METHODS AND RESULTS: To determine whether oxidative stress is increased, serum concentrations of both TRX and alpha-tocopherol (vitamin E) were determined in 12 control subjects without any coronary risk factors (CONTROL), 6 current smokers (SMOKING), 19 hypertensive patients (HT), 7 hypercholesterolemic patients (HC) and 14 subjects with multiple risk factors (MULTIPLE). Patients with diabetes mellitus were not included. The serum TRX concentrations (mean +/- SD ng/ml) were significantly higher in SMOKING (41+/-10), HT (41+/-17), HC (48+/-15) and MULTIPLE (46+/-15) than in CONTROL (24+/-11). The serum alpha-tocopherol concentrations (mg/g lipids) were not significantly different among CONTROL (4.0+/-0.7), SMOKING (4.0+/-0.8), HT (4.1+/-0.6) and HC (4.2+/-0.6), although the concentration was significantly lower in MULTIPLE (3.3+/-0.7) than in any of the other study groups. CONCLUSIONS: SMOKING, HT, HC and MULTIPLE had significantly higher serum TRX concentrations than CONTROL, suggesting increased oxidative stress. MULTIPLE had a lower serum concentration of antioxidant alpha-tocopherol than any of the other study groups, suggesting impaired or exhausted defense against chronic oxidative stress in the presence of the multiple risk factors.