Tomato-based functional food as interferon adjuvant in HCV eradication therapy

Oxidative stress, endogenous antioxidants, alcohol, and hepatitis C: pathogenic interactions and therapeutic considerations

Hepatitis C virus (HCV) is a blood-borne pathogen that was identified as an etiologic agent of non-A, non-B hepatitis in 1989. HCV is estimated to have infected at least 170 million people worldwide. The majority of patients infected with HCV do not clear the virus and become chronically infected, and chronic HCV infection increases the risk for hepatic steatosis, cirrhosis, and hepatocellular carcinoma. HCV induces oxidative/nitrosative stress from multiple sources, including inducible nitric oxide synthase, the mitochondrial electron transport chain, hepatocyte NAD(P)H oxidases, and inflammation, while decreasing glutathione. The cumulative oxidative burden is likely to promote both hepatic and extrahepatic conditions precipitated by HCV through a combination of local and more distal effects of reactive species, and clinical, animal, and in vitro studies strongly point to a role of oxidative/nitrosative stress in HCV-induced pathogenesis. Oxidative stress and hepatopathogenesis induced by HCV are exacerbated by even low doses of alcohol. Alcohol and reactive species may have other effects on hepatitis C patients such as modulation of the host immune system, viral replication, and positive selection of HCV sequence variants that contribute to antiviral resistance. This review summarizes the current understanding of redox interactions of HCV, outlining key experimental findings, directions for future research, and potential applications to therapy.

Ribavirin monitoring in chronic hepatitis C therapy: anaemia versus efficacy

The standard treatment of HCV infection with pegylated interferon-alpha2a or -alpha2b and ribavirin is effective in <50% of HCV genotype-1-infected patients. To improve this figure, it might be desirable to obtain optimal plasma concentrations of the drug by increasing the dose. Unfortunately, there is great interpatient variability in ribavirin pharmacokinetics. In the present review, we describe the mechanism of ribavirin-induced anaemia in detail, evaluate host predictive factors for this harmful side effect and assess the literature data on attempts to improve the sustained virological response rate by increasing the dose of ribavirin. We suggest an optimal steady-state concentration range for ribavirin in monoinfected and coinfected patients. Lastly, we propose that it would be of particular value to monitor ribavirin concentrations in HCV genotype-1-infected patients and (regardless of the genotype) coinfected patients, haemodialyzed patients and obese patients.

The impact of diet on liver fibrosis and on response to interferon therapy in patients with HCV-related chronic hepatitis

BACKGROUND AND AIMS

A deranged metabolic status and alcohol intake may trigger induction and progression of chronic hepatitis C virus (HCV) liver disease. The aim of this study was to evaluate whether dietary composition affects the severity of liver damage and response to therapy in patients with HCV-related chronic hepatitis.

METHODS

We enrolled 1,084 patients with biopsy-proven HCV-related chronic hepatitis (432 treated with interferon plus ribavirin) and 2,326 healthy subjects in this prospective study conducted in a university hospital. Dietary habits were recorded in enrolled individuals, and their alcohol consumption was evaluated with a questionnaire (AUDIT). Body mass index, and plasma levels of blood glucose, nitrogen, creatinine, cholesterol, and triglycerides were also measured. All individuals underwent routine liver tests and HCV genotyping.

RESULTS

At study onset, there were no differences in metabolic status or alcohol consumption between patients and controls. About 50% of each group was overweight, and about 60% consumed alcohol. Patients and controls had similar dietary habits. Intake of carbohydrates, lipids and polyunsaturated fatty acids, and alcohol consumption were independent factors of liver damage at histology (logistic regression analysis). Some dietary components (unsaturated fatty acids, iron, zinc, vitamin A, and niacin) and alcohol intake differed significantly (P < 0.05 and P 0.01, respectively; univariate analysis) between responders and nonresponders to interferon therapy. Genotype, age, body mass index, steatosis, and fibrosis were independent predictors of therapy outcome (P < 0.02; multivariate analysis).

CONCLUSIONS

The severity of HCV-related chronic hepatitis depends on a variety of factors. Our results show that dietary composition is related to the extent of liver damage. Although traditional risk factors independently affected treatment response, some dietary components were associated with nonresponse to therapy in our patients. This suggests that HCV patients may benefit from instructions regarding their diet.

Redox regulation of hepatitis C in nonalcoholic and alcoholic liver

Hepatitis C virus (HCV) is an RNA virus of the Flaviviridae family that is estimated to have infected 170 million people worldwide. HCV can cause serious liver disease in humans, such as cirrhosis, steatosis, and hepatocellular carcinoma. HCV induces a state of oxidative/nitrosative stress in patients through multiple mechanisms, and this redox perturbation has been recognized as a key player in HCV-induced pathogenesis. Studies have shown that alcohol synergizes with HCV in the pathogenesis of liver disease, and part of these effects may be mediated by reactive species that are generated during hepatic metabolism of alcohol. Furthermore, reactive species and alcohol may influence HCV replication and the outcome of interferon therapy. Alcohol consumption has also been associated with increased sequence heterogeneity of the HCV RNA sequences, suggesting multiple modes of interaction between alcohol and HCV. This review summarizes the current understanding of oxidative and nitrosative stress during HCV infection and possible combined effects of HCV, alcohol, and reactive species in the pathogenesis of liver disease.

Vitamin E and C supplementation prevents decrease of eicosapentaenoic acid in mononuclear cells in chronic hepatitis C patients during combination therapy of interferon alpha-2b and ribavirin

OBJECTIVE

We investigated the effects of vitamin E and C supplementation on the fatty acid composition of mononuclear cells and on the clinical observations in patients who had chronic hepatitis C and received interferon-alpha-2b (IFN-alpha-2b) and ribavirin combination therapy.

METHODS

Patients were randomly allocated to receive daily 500 mg of vitamin E and 750 mg of vitamin C (vitamin group, n = 14) or no supplement (non-vitamin group, n = 16) in addition to IFN-alpha-2b and ribavirin therapy. The fatty acid composition of mononuclear cell phospholipids was analyzed before and at 2, 4, and 8 wk after treatment.

RESULTS

After vitamin supplementation, plasma and red blood cell alpha-tocopherol and plasma ascorbic acid levels increased in the vitamin group. Serum levels of alanine aminotransferase decreased significantly after 2 wk of treatment in both groups. At the start of treatment, a lower level of eicosapentaenoic acid (EPA) and a higher level of the molar ratio of arachidonic acid to EPA in mononuclear cells were observed in the present patients compared with healthy volunteers, and a significant correlation between the molar ratio and serum alanine aminotransferase level was found. The EPA level of mononuclear cells was maintained in the vitamin group during treatment, whereas a significant decrease was observed in the non-vitamin group at 4 and 8 wk after treatment.

CONCLUSIONS

Antioxidant vitamin supplementation during IFN-alpha-2b and ribavirin therapy prevented a decrease in EPA of mononuclear cell phospholipids. If a further decrease in the ratio of arachidonic acid to EPA can be achieved by using oral EPA supplementation, the efficacy of IFN-alpha-2b and ribavirin therapy may be improved.

Hepatitis C virus and oxidative stress: a dangerous liaison

Chronic hepatitis C infection persists in more than 170 million people worldwide and is one of the major causes of hepatic failure and liver transplantation. Recent studies have demonstrated that hepatitis C virus (HCV)-derived proteins have the capacity to generate substantial oxidative stress within the hepatocyte. Subsequently, oxidative stress has been identified as a significant mechanistic pathway culminating in the development of hepatic cirrhosis, liver failure and liver cancer. In vitro HCV-induced oxidative stress has been demonstrated to activate cellular signaling pathways involved in both inflammatory and fibrogenic responses. In addition, oxidative stress has also been shown to play a role in HCV replication. Preliminary data from small clinical trials have implicated oxidative stress as a risk factor for liver fibrosis and increased HCV viral load. Although conclusive evidence from large-scale clinical trials is lacking, it is possible that antioxidant co-therapies may improve hepatic inflammation, retard fibrosis progression and improve the ability to achieve a sustained viral response with standard antiviral therapy.

Traitements complémentaires de l’hépatite chronique virale C

Pegylated interferon and ribavirin combination therapy represent the standard-of-care treatment for chronic hepatitis C, that allows to cure more than half of the patients. However, the success of this bitherapy is in balance with numerous side effects, especially hematologic and psychiatric. This review is focused on complementary treatments (erythropoietin, G-CSF, vitamin E, glutathion, ursodeoxycholic acid and antidepressants) likely to bring a benefit in maintaining adequate interferon and ribavirin dosages and in improving quality of life. This analysis has been performed by using the Medline(R) data base and with data from laboratories which commercialized these molecules. Erythropoietin, G-CSF and antidepressants are the best tools to optimize the bitherapy in its dose and its duration while privileging the quality of life of HCV-infected patients.

Dietary antioxidant compounds and liver health

Chronic liver damage is a widespread pathology characterized by a progressive evolution from steatosis to chronic hepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma. As the oxidative stress plays a central role in liver diseases pathogenesis and progression, the use of antioxidants have been proposed as therapeutic agents, as well as drug coadjuvants, to counteract liver damage. In this work in vitro and in vivo studies, with emphasis on humans and animals experiments, have been considered and reviewed according to antioxidant typologies. Great differences emerge as far as ingested doses, bioavailability and liver ability to accumulate the various compounds. Results available up to now suggest that lycopene-rich foods could be proposed in therapeutic treatment of some liver pathologies. On the other hand contradictory results have been obtained with alpha-tocopherol, beta-carotene and trans-resveratrol. Quercetin, silymarin, esculetin and thyme and rosemary among phenolic compounds need further studies.

Functional foods: Planning and development

The discussion on functional foods among scientific communities and EC commissions is mainly focused on definitions and on legislative issues related to the presence on the market of this kind of products. Although many new products continuously appear, the functional food market is characterized by a high rate of failure. To realize a successful functional food, experts having different background should work together following a detailed workplan. In this paper, the problems related to planning and development of functional foods are considered using a step-by-step approach. The strategies for invention and development, formulation and validation of nutritional claims are regarded also illustrating practical examples of functional food development. The concept of food for special medical purposes, intended for individuals who are being treated under medical supervision, is also introduced.