Oxidative stress in chronic hepatitis C: the effect of interferon therapy and correlation with pathological features

To evaluate the oxidative stress parameters before, during and after interferon treatment.

Twenty patients were treated with interferon a2b 5 MU, three times a week, subcutaneously, for 12 months. Liver biopsy was performed six months before treatment and at the six month follow-up. Chromosomal breakage studies were evaluated by the adjusted clastogenic score (ACS, normal value [nv] 1.1 +/- 2.4%). Plasma malondialdehyde (MDA) was measured according to the Yagi method (nv 6.6 +/- 1.4 nmol/mL) and total thiols using the Ellman's reagent (DTNB) (nv 9.8 +/- 1.3 micromol/g protein). A serum marker of fibrogenesis, the amino-terminal propeptide of Procollagen type III (PIIIP), was quantified by radioimmunoassay (nv 0.37 +/- 0.18 U/L).

Compared with reference samples, the plasma of patients before treatment showed an increase of ACS (9.2 +/- 3.2%, P<0.001); higher MDA values (12.6 +/- 2.7 nmol/mL, P<0.001) and total plasma sulfhydryl groups (t-SH) were decreased (6.3 +/- 1.1 micromol/g protein, P<0.001). During treatment and at the follow-up, a decrease in ACS was noticed in all patients (P<0.001), but without normalization; a decrease in MDA was seen, with progressive normalization until the end of the follow up only in sustained responders (P<0.003), while an increase of t-SH was seen, with progressive normalization until the end of follow up in all patients (P<0.005). A positive correlation of ACS with grading of inflammation was found (r=0.52, P<0.03) but not with fibrosis staging. In contrast, plasma MDA correlates with fibrosis staging (r=0.51, P<0.03) and with PIIIP (r=0.57, P<0.03) but without grading of inflammation.

The present study confirmed the presence of oxidative stress in chronic hepatitis C patients. Interferon promotes a long term inhibition of oxidative stress with concomitant improvement of activity and fibrosis. In the management of chronic hepatitis C, adjuvant therapy with antioxidants could be useful.