Cytogenetic methods for detection of oxidative stress and evaluation of antioxidant therapy in hepatitis C infection.

The plasma of patients with hepatitis C contains chromosome-damaging substances, the so-called "clastogenic factors" (CFs), as this is the case for other chronic inflammatory diseases and after radiation exposure. These endogenous clastogens, formed as a consequence of increased superoxide production by inflammatory cells, can be detected with cytogenetic methods, as they are used for exogenous clastogens. The long-lived, autosustained DNA-damaging effects of CFs are risk factors for the development of cancer and leukemia. In hepatitis C, the highest clastogenic scores has been observed in patients with hepatocellular carcinoma. In agreement with the link to inflammation, clastogenic score are correlated with necro-inflammatory scores in liver biopsies. Antioxidant therapy with a powerful superoxide scavenger resulted in normalization of clastogenic scores and significant decreases in aminotransferase levels, but did not influence the virus load. Preliminary results of our study on a limited number of patients suggest that pre-treatment with antioxidants may improve the outcome of interferon/ribavirin treatment. A comparison of a three-month treatment with either interferon alone or the antioxidant alone, yielded similar results for reduction of ALT levels, but only complete normalization of clastogenic scores for the antioxidant. Further studies have to be conducted to see whether a combination of an antiviral agent with an appropriate antioxidant would allow to reduce interferon and its side effects.Combination of antioxidants with IFN/RIBA was also reported by other authors with discordant results. The CF-test can be useful in clinical trials for the choice of the appropriate antioxidant.

Clastogenic plasma factors in psoriasis--comparison of phototherapy and anti-TNF-α treatments.

As previously described, Psoralen plus UVA (PUVA) therapy induces chromosome damage in psoriatic patients. This study evaluates whether these effects are transitory or persistent. In addition, we studied these effects after narrowband UVB (nUVB) and anti-tumor necrosis factor (TNF)-α treatments. Among 40 responder patients, 10 received PUVA, 10 nUVB, 10 Infliximab and 10 Etanercept. Disease activity was determined with Psoriasis Area and Severity Index. Chromosomal breakage was evaluated by the clastogenic factor (CF) test. Potential clastogenic agents, malondialdehyde (MDA) and TNF-α were measured. Before treatment, the plasma-adjusted clastogenic scores (ACS) of patients were increased. During treatment, a further increase in ACS was observed in both phototherapy groups. Chromosome damage persisted for PUVA patients at week 32, while it diminished after nUVB to ACS values lower than before treatment. MDA and TNF-α values were also increased at baseline. MDA decreased during treatment in all groups, but without reaching normal levels. Plasma TNF-α remained unchanged in PUVA and nUVB but decreased in both anti-TNF-α treatment groups. Psoriasis is accompanied by CF-induced chromosomal breakage that increases during PUVA and nUVB treatments. Plasma clastogenic activity persisted in the follow-up after PUVA, while after nUVB ACS returned to values even lower than baseline. Clastogenic activity during the induction phase with anti-TNF-α remained unchanged.

Clastogenic factors in the plasma of patients with hepatitis C: their possible role at the origin of hepatocarcinoma.

Clastogenic factors (CF) are endogenous clastogens composed of lipid peroxidation products, cytokines, and abnormal nucleotides of inosine. They are regularly observed after radiation exposure and in chronic inflammatory diseases, where they are supposed to be risk factors for carcinogenesis. In the present study, we evaluate clastogenic activity in the plasma of patients with chronic hepatitis C, HCV-positive liver cirrhosis, and hepatocarcinoma in comparison to liver metastasis. Plasma ultrafiltrates from patients were added to blood cultures of healthy donors (CF test). The chromosomal aberration rates observed in 100 metaphases after 48 hours of cultivation were expressed as adjusted clastogenic scores (ACS). The differences in ACS between the four patient groups and controls were highly significant and represented a 10-fold increase in chromatid-type aberrations. The ACS of patients with cirrhosis and hepatocarcinoma were higher than those of hepatitis patients without these complications, but the differences did not reach statistical significance. Because of cytotoxic effects, the cultures did not grow for 10/17 patients with hepatocarcinoma and were repeated with a reduced volume of ultrafiltrate (0.1 instead of 0.25 mL). The ACS were highest in these 10 patients. When the CF activity of HCV-positive hepatocarcinoma was compared to metastasis because of other malignancies, the differences in ACS were highly significant for the cultures set up with the reduced quantity of ultrafiltrate. The percentage of CF-positive samples was 100% for hepatocarcinoma and 9% for metastasis. The results show that the chromosome-damaging effects of CF increase as the disease progresses to cirrhosis and liver cancer. Formed via the intermediacy of superoxide and generating more superoxide, CF are responsible for an autosustained, long-lived DNA-damaging process, which is documented at the chromosomal level by our technique.

Clastogenic factors as potential biomarkers of increased superoxide production.

The formation of clastogenic factors (CF) and their damaging effects are mediated by superoxide, since superoxide dismutase is regularly protective. CF are produced via superoxide and stimulate the production of superoxide by monocytes and neutrophils. This results in a selfsustaining and longlasting process of clastogenesis, which may exceed the DNA repair system and ultimately lead to cancer (Emerit, 1994). An increased cancer risk is indeed observed in conditions accompanied by CF formation. These include irradiated persons, patients with chronic inflammatory diseases, HIV-infected persons and the chromosomal breakage syndromes ataxia telangiectasia, Bloom's syndrome and Fanconi's anemia. Biochemical analysis has identified lipid peroxidation products, arachidonic acid metabolites, nucleotides of inosine and cytokines, in particular tumor necrosis factor alpha, as the clastogenic and also superoxide stimulating components of CF. Due to their chromosome damaging effects, these oxidants can be detected with classical cytogenetic techniques. Their synergistic action renders the CF-test particularly sensitive for the detection of a pro-oxidant state. Correlations were observed between CF and other biomarkers of oxidative stress such as decreases in total plasma thiols or increases in TBARS or chemiluminescence. Correlations between CF and disease activity, between CF and radiation exposure, suggest the study of CF for monitoring these conditions. CF may also be useful as biochemical markers and intermediate endpoints for the evaluation of promising antioxidant drugs.CF formation represents a link between chronic inflammation and carcinogenesis. Prophylactic use of superoxide scavengers as anticarcinogens is therefore suggested.

Oxidative stress in chronic hepatitis C: a preliminary study on the protective effects of antioxidant flavonoids.

BACKGROUND/AIMS: Oxidative stress is involved in chronic hepatitis C, and efforts have been made to influence the disease process with antioxidants. The present study evaluates the protective effects of a phenol-rich processed grain food with superoxide-scavenging properties (trade name antioxidant biofactor AOB). METHODOLOGY: Thirty patients participated in this placebo-controlled double-blind pilot study. AOB was taken orally by fifteen patients for 3 mo at the recommended daily dose of 3x2 sachets, containing 3 g of powder each. Another fifteen patients received a herbal extract with practically no superoxide scavenging properties as a placebo. Oxidative stress biomarkers, aminotransferase levels and viral load were evaluated immediately before and after treatment. RESULTS: AOB treatment considerably improved the antioxidant defenses. Also ALT and AST decreased in 11 of the 15 patients (-11% to -65%, mean -22%, p<0.05). The effects of placebo were not significant. Viral load remained unchanged. Control biopsies were not done after the short interval of 3 mo. There were no adverse effects. After the 3-mo treatment with AOB or placebo, 16 of the 30 patients received conventional antiviral treatment (pegylated interferon alpha and ribavirin). A sustained response was observed in 5 of 9 AOB pretreated patients six mo after discontinuation of the 12-mo antiviral therapy. The 7 patients pretreated with placebo were all non-responders. CONCLUSIONS: These preliminary results are encouraging to conduct more extensive clinical studies combining antioxidant with antiviral treatment in hepatitis C.

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

AIMS: To evaluate the oxidative stress parameters before, during and after interferon treatment. PATIENTS/METHODS: 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). RESULTS: 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. CONCLUSIONS: 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.