Serum thioredoxin levels as a predictor of steatohepatitis in patients with nonalcoholic fatty liver disease

BACKGROUND/AIMS: Thioredoxin (TRX) is a stress-inducible thiol-containing protein. The aim of this study was to evaluate the clinical significance of serum TRX in patients with nonalcoholic steatohepatitis (NASH) or simple steatosis. METHODS: Serum TRX levels were determined using an enzyme-linked immunosorbent assay kit in 25 patients with NASH, 15 patients with simple steatosis, and 17 healthy volunteers. RESULTS: Serum TRX levels (medians and (ranges), ng/ml) were significantly elevated in patients with NASH (60.3 (17.6-104.7)), compared to those in patients with simple steatosis (24.6 (16.6-69.7), P=0.0009) and in healthy controls (23.5 (1.3-50.7), P<0.0001). Serum ferritin levels in patients with NASH were also significantly higher than the levels in patients with simple steatosis. The receiver operating characteristic curve confirmed that serum TRX and ferritin levels were predictors for distinguishing NASH from simple steatosis. Higher grades of histological iron staining were observed in NASH than in simple steatosis. Serum TRX tended to increase in accordance with hepatic iron accumulation and the histological severity in patients with NASH. CONCLUSIONS: The pathogenesis of NASH may be associated with iron-related oxidative stress. The serum TRX level is a parameter for discriminating NASH from simple steatosis as well as a predictor of the severity of NASH.