Effect of alcohol abuse on HCV replication

Alcoholic liver disease and hepatitis C: A frequently underestimated combination

Alcoholic liver disease (ALD) and hepatitis C virus (HCV) infection represent, either alone or in combination, more than two thirds of all patients with liver disease in the Western world. This review discusses the epidemiology and combined impact of ALD and HCV on the progression of liver disease. ALD and HCV affect the progression of liver disease to liver cirrhosis and hepatocellular carcinoma (HCC) in a synergistic manner. Thus, the risk for HCC increases five times with a daily alcohol consumption of 80 g; in the presence of HCV it is increased 20-fold, and a combination of both risk factors leads to a more than 100-fold risk for HCC development. Alcohol consumption also decreases the response to interferon treatment which is probably due to a lack of compliance than a direct effect on HCV replication. Several molecular mechanisms are discussed that could explain the synergistic interaction of alcohol and HCV on disease progression. They include modulation of the immune response and apoptosis, increased oxidative stress via induction of CYP2E1 and the hepatic accumulation of iron. Thus, both HCV and alcohol independently cause hepatic iron accumulation in > 50% of patients probably due to suppression of the liver-secreted systemic iron hormone hepcidin. A better understanding of hepcidin regulation could help in developing novel therapeutic approaches to treat the chronic disease in the future. For now, it can be generally concluded that HCV-infected patients should abstain from alcohol and alcoholics should be encouraged to participate in detoxification programs.

Interrelationship between alcohol intake, hepatitis C, liver cirrhosis, and hepatocellular carcinoma

The discovery of a cDNA clone of hepatitis C virus (HCV) genome in 1989 has resulted in numerous reports of high rates of the prevalence of HCV antibody in patients with alcoholic liver disease, in particular, alcoholic liver cirrhosis and hepatocellular carcinoma. Thus, the interaction between alcohol intake and HCV infection has become of great importance. In terms of the effect of alcohol on HCV-RNA levels, the data are controversial; in some reports, alcohol increases HCV-RNA levels, and in the other reports it does not. There are several reports suggesting the possibility of an elevated quasi-species of hypervariable region 1 in the HCV genome caused by alcohol drinking. Recent studies have documented that alcohol intake exaggerates the responsiveness of interferon therapy for chronic hepatitis C; however, its mechanism is still obscure. Several studies have suggested the promoting effect of alcohol on the development of hepatocellular carcinoma in type C liver cirrhosis, which has been similarly observed in type B chronic liver disease, whereas its mechanism is limited to speculations.

Impact of alcohol on the histological and clinical progression of hepatitis C infection

In patients infected with the hepatitis C virus (HCV), 20% to 30% will progress to cirrhosis in over two to three decades. Viral and host factors that are important in the clinical and histologic progression of HCV infection are not entirely certain. It has been suggested that liver disease is worse in alcoholics infected with HCV. In the present retrospective study, we examined the effect of moderate alcohol intake on the histologic and clinical progression of HCV infection and assessed whether other variables such as gender, length of exposure, mode of exposure, HCV RNA levels, and ferritin levels also independently impacted disease progression. Liver biopsies were analyzed for the degree of fibrosis, presence of cirrhosis, and histologic activity by using the Histologic Activity Index of Knodell. Patients were divided into two groups based on whether their alcohol intake was significant or not significant. Significant alcohol intake was defined as > 40 g alcohol/day in women and > 60 g of alcohol/day in men for > 5 years. Groups were further divided based on the decades of exposure to HCV. There was no difference in the age or length of exposure to HCV in the alcohol and the alcohol-free group. HCV RNA serum levels, ferritin levels, and viral genotypes were similar in both groups. There was a two- to threefold greater risk of liver cirrhosis and decompensated liver disease in the alcohol group. Also, the rate to which subjects developed cirrhosis was faster in the alcohol group with 58% being cirrhotic by the second decade as opposed to 10% being cirrhotic in the nonalcohol group by the second decade. The histologic and clinical acceleration of liver disease was independent of the mode of exposure or sex. In summary, alcohol intake is an independent risk factor in the clinical and histologic progression of HCV infection.

How much does alcohol contribute to the variability of hepatic fibrosis in chronic hepatitis C?

In order to determine the contribution of alcohol intake to the severity of hepatic fibrosis in patients with chronic hepatitis C, we studied associations between various levels of alcohol intake, other demographic variables and semiquantitative liver histology in 434 cases of chronic hepatitis C. Clinical, demographic and disease-related data were entered into a relational database. Liver histology was scored according to Scheuer. The average daily alcohol intake for the year preceding liver biopsy (recent exposure) and for earlier periods (past exposure) was categorized into five levels of intake. One-third of patients gave a history of alcohol intake that had exceeded 40 g/day for at least 5 years. By univariate analysis, age, but not recent or past alcohol intake or other baseline variables, was associated with portal score (r = 0.14, P = 0.004), fibrosis score (r = 0.46, P < 0.001), total Scheuer score (r = 0.35, P < 0.001). However, by multivariate analysis, age (P < 0.001), past (but not present) alcohol intake (P < 0.001) and birth in Egypt (P = 0.006) were independently associated with fibrosis score. Age, past alcohol and birth place in Egypt contributed 27% to total variance of the hepatic fibrosis score, while age alone accounted for 23%. Age also independently predicted portal activity (P = 0.02) and total Scheuer score (P < 0.001), whereas past alcohol intake correlated with total Scheuer score (P = 0.002) but not with other histological indices. A separate multivariate analysis was performed on a more homogeneous subgroup of 196 patients who acquired hepatitis C by injection drug use. In this subgroup, age (P < 0.05) and past alcohol (P < 0.05) were independently associated with fibrosis score. In both the overall and subgroup analyses, there was a threshold level of past alcohol intake (>80 g/day) beyond which the risk of fibrosis increased significantly. It is concluded that toxic levels of alcohol exposure for at least 5 years accentuate hepatic fibrosis in hepatitis C but the influence of alcohol appears to be minor compared with age and other variables and is exerted only at toxic levels of intake.

Efficacy of interferon therapy in patients with chronic hepatitis C. Comparison between non-drinkers and drinkers

BACKGROUND

Alcohol has been reported to be an important factor that modulates the development and prognosis of chronic viral hepatitis; however, little is known about interaction of alcohol intake and chronic hepatitis C. The aim of this study was to examine whether alcohol drinking affects the effectiveness of interferon (IFN) therapy for chronic hepatitis C.

METHODS

Thirty-nine patients with chronic hepatitis C were divided into three groups on the basis of the amount of alcohol intake before IFN therapy: group I (n = 15), non-drinkers; group II (n = 14), less than 70 g/day; and group III (n = 10), more than 70 g/day of ethanol intake for at least 10 years. The IFN (total dose, 330 +/- 206 MU) was administered daily for 2 weeks and then intermittently. Drinkers stayed abstinent for at least 1 month before, during, and after IFN therapy. The sustained responder was defined as the patient who showed normal alanine aminotransferase (ALAT) levels continuously for more than 6 months after the therapy. The liver histology (HAI score) and serum hepatitis C virus (HCV) RNA were also examined before and after the therapy.

RESULTS

There was no significant difference among the three groups in the level of ALAT before IFN therapy, age, total dose of IFN, and liver histology. The rates of sustained responders in groups I, II, and III were 53.3%, 42.9%, and 0%, respectively, resulting in a significantly lower rate in group III than in groups I (p < 0.01) and II (p < 0.01). The serum HCV-RNA turned negative after the therapy in 58.3%, 20.0%, and 12.5% of groups I, II, and III, respectively, leading to a significantly lower rate of disappearance of HCV-RNA in group III than in group I (p < 0.05).

CONCLUSION

The IFN therapy for chronic hepatitis C was less effective in heavy drinkers than in non-drinkers.