Following the advent of direct-acting antivirals (DAAs), the treatment of hepatitis C virus (HCV) infection is now rarely challenging. However, data are still limited concerning DAA use in patients affected by glucose-6-phosphate dehydrogenase deficiency (G6PDd). Based on these considerations, the goal of this study was to evaluate the effectiveness and safety of DAAs in this subpopulation. A retrospective multicenter observational study (2015-2023) was conducted on all 2754 consecutive HCV-positive patients treated with first- and second-generation all-oral DAAs, and with a G6PDd diagnosis confirmed by quantitative testing (n = 38). At the treating clinician's discretion, an enhanced clinical and laboratory follow-up was performed, generally on a monthly basis both during treatment and up to six months after the end of it. Concerning hematochemical parameters, no significant differences were found between any considered time point. In all cases, no treatment-related adverse events were reported, and virologic response rates were as expected without G6PDd. In conclusion, in a large experience which, to the best of our knowledge, is unprecedented in the literature, the treatment of HCV hepatitis with nearly all available DAAs in patients with G6PDd as a comorbidity-a common occurrence in countries such as Italy-proved to be highly effective and safe.

Aging has been linked to several degenerative processes that, through the accumulation of molecular and cellular damage, can progressively lead to cell dysfunction and organ failure. Human aging is linked with a higher risk for individuals to develop cancer, neurodegenerative, cardiovascular, and metabolic disorders. The understanding of the molecular basis of aging and associated diseases has been one major challenge of scientific research over the last decades. Mitochondria, the center of oxidative metabolism and principal site of reactive oxygen species (ROS) production, are crucial both in health and in pathogenesis of many diseases. Redox signaling is important for the modulation of cell functions and several studies indicate a dual role for ROS in cell physiology. In fact, high concentrations of ROS are pathogenic and can cause severe damage to cell and organelle membranes, DNA, and proteins. On the other hand, moderate amounts of ROS are essential for the maintenance of several biological processes, including gene expression. In this review, we provide an update regarding the key roles of ROS-mitochondria cross talk in different fundamental physiological or pathological situations accompanying aging and highlighting that mitochondrial ROS may be a decisive target in clinical practice.

The purpose of this study was to evaluate the association between therapy-induced hemoglobin (Hb) decreasing rapidity and severity with erythrocyte inosine triphosphatase (ITPase) activity and ATP concentration in chronic hepatitis C patients receiving chronic hepatitis C (HCV) treatment. Forty-three Japanese patients were included in the study. Erythrocyte ITPase activity before therapy was determined by HPLC-UV. Erythrocyte ATP concentrations before and during therapy were determined by luciferase assay. Genotyping for ITPA 94C>A (rs1127354) and IVS2+21 A>C (rs7270101) was conducted using TaqMan probes. The median ITPase activity (µmol/h/g hemoglobin) of ITPA 94 CC, CA, and AA genotypes was 136.8 (range, 80.4-289.6), 41.1 (24.3-93.1), and 11.8, respectively. ITPase activity and Hb decreasing showed a significantly inverse relationship at therapeutic weeks 2, 4, and 6 (p<0.01). Erythrocyte ATP concentration was decreased by therapy, and Hb decreasing was significantly and inversely correlated with erythrocyte ATP concentration at week 4 and after week 8 (p<0.001 and 0.05, respectively). ATP concentration for patients with ITPA 94CA was significantly lower than ITPA 94CC at week 4 (p=0.045). We concluded that ITPase activity plays an important function and that ATP concentration changes due to therapy are related to the Hb decreasing mechanism in the early period of therapy with HCV treatment.

In the last decade, pegylated interferon-α (PegIFN-α) plus ribavirin (RBV) was the standard treatment of chronic hepatitis C for genotype 1, and it remains the standard for genotypes 2 and 3. Recent studies reported associations between RBV-induced anemia and genetic polymorphisms of concentrative nucleoside transporters such as CNT3 (encoded by SLC28A3) and inosine triphosphatase (encoded by ITPA). We aimed at studying genetic determinants of RBV kinetics, efficacy and treatment-associated anemia.

We included 216 patients from two Swiss study cohorts (61% HCV genotype 1, 39% genotypes 2 or 3). Patients were analyzed for SLC28A2 single nucleotide polymorphism (SNP) rs11854484, SLC28A3 rs56350726, and SLC28A3 rs10868138 as well as ITPA SNPs rs1127354 and rs7270101, and followed for treatment-associated hemoglobin changes and sustained virological response (SVR). In 67 patients, RBV serum levels were additionally measured during treatment.

Patients with SLC28A2 rs11854484 genotype TT had higher dosage- and body weight-adjusted RBV levels than those with genotypes TC or CC (p=0.02 and p=0.06 at weeks 4 and 8, respectively). ITPA SNP rs1127354 was associated with hemoglobin drop ≥3 g/dl during treatment, in genotype (relative risk (RR)=2.1, 95% CI 1.3-3.5) as well as allelic analyses (RR=2.0, 95%CI 1.2-3.4). SLC28A3 rs56350726 was associated with SVR in genotype (RR=2.2; 95% CI 1.1-4.3) as well as allelic analyses (RR=2.0, 95% CI 1.1-3.4).

The newly identified association between RBV serum levels and SLC28A2 rs11854484 genotype, as well as the replicated association of ITPA and SLC28A3 genetic polymorphisms with RBV-induced anemia and treatment response, may support individualized treatment of chronic hepatitis C and warrant further investigation in larger studies.

Today, treatment of chronic hepatitis C is based on a synergistic combination of pegylated interferon and ribavirin with antiprotease inhibitors. Haemolytic anaemia, which is the major side effect of ribavirin treatment, disrupts ribavirin treatment compliance and varies significantly from one patient to another. There is an individual susceptibility to ribavirin haemolysis. With a view to studying haemolysis, and thus optimizing the treatment response, we have developed a new in vitro tool for analysing the ribavirin-induced lysis of red blood cells.

Resuspended red blood cells were incubated with isotonic buffer and a range of concentrations of ribavirin. Haemolysis was quantified by spectrophotometric measurement of the supernatant at 540 nm. The assay was used to test the effects of various compounds and to investigate the susceptibility of patients to haemolytic anaemia.

In our assay, the degree of haemolysis is dependent on the ribavirin concentration used and can be inhibited by the addition of dipyridamole (50% inhibitory concentration [IC(50)] 30 μM), ATP or glutathione (IC(50) 1.63 mM and 767 μM, respectively). We observed a strong decrease in red blood cell haemolysis in the presence of the ribavirin prodrug viramidine (Taribavirin(®)). When testing the performance of this assay with blood from 24 patients before treatment, we observed a strong correlation between in vitro haemolysis before treatment and the decrease in haemoglobin levels seen in vivo during subsequent treatment (P<0.001).

With this new tool it is possible to better evaluate individual susceptibility to ribavirin-induced haemolysis before the start of treatment. In addition, this model will enable the mechanism of ribavirin-induced anaemia to be further explored and allow molecules that could reduce ribavirin haemolysis to be screened and tested in vitro. This approach could help optimize current and future therapeutic strategies involving ribavirin in the treatment of chronic hepatitis C.

Chronic hepatitis C (CHC) infection, usually an asymptomatic infection, has long-term serious complications such as cirrhosis, hepatocellular carcinoma, and end-stage liver disease requiring liver transplantation (LT). Several novel drugs against hepatitis C which form part of 'specifically targeted antiviral therapy for hepatitis C' (STAT-C) have been developed. These include NS3/4A protease inhibitors telaprevir, boceprevir, and nucleoside/non-nucleoside polymerase inhibitors (NS5A) which hold promise for future therapy. Despite the development of new anti-hepatitis C virus (HCV) drugs, ribavirin (RBV) remains the single most important drug to prevent relapse and is frequently included among newer regimens being developed with novel small molecule anti-HCV drugs. The current approved treatment is a combination therapy of once weekly subcutaneous pegylated-interferon (PEG-IFN)-α plus body-weight-based oral RBV regimen. The most significant dose-dependent side effect of RBV is hemolytic anemia warranting dose reduction or discontinuation in severe cases compromising sustained virological response (SVR). Monitoring RBV plasma concentration has been challenging due to its peculiar pharmacokinetics and has been done to predict both efficacy and toxicity. Herein, we review the pharmacological profile of RBV and the monitoring of its plasma concentration, monitoring in renal impairment, post-LT, and human immunodeficiency virus (HIV)-HCV co-infection in patients being treated with combination therapy of PEG-IFN-α and RBV.

Combined pegylated interferon (PegIFN) and ribavirin represents the standard therapy for patients with chronic hepatitis C (CHC), which allows for sustained viral response (SVR) in up to 90% of patients depending on certain viral and host factors. Clinical studies have demonstrated the importance of adherence to therapy, that is, the ability of patients to tolerate and sustain a fully dosed therapy regimen. Adherence is markedly impaired by treatment-related adverse effects. In particular, haemolytic anaemia often requires dose reduction or termination of ribavirin treatment, which compromises treatment efficacy. Recent evidence points to a beneficial role of recombinant erythropoietin (EPO) in alleviating ribavirin-induced anaemia thereby improving quality of life, enabling higher ribavirin dosage and consequently improving SVR. However, no general consensus exists regarding the use of EPO for specific indications: its optimal dosing, treatment benefits and potential risks or cost efficiency. The Swiss Association for the Study of the Liver (SASL) has therefore organized an expert meeting to critically review and discuss the current evidence and to phrase recommendations for clinical practice. A consensus was reached recommending the use of EPO for patients infected with viral genotype 1 developing significant anaemia below 100 g/L haemoglobin and a haematocrit of <30% during standard therapy to improve quality of life and sustain optimal ribavirin dose. However, the evidence supporting its use in patients with pre-existing anaemia, non-1 viral genotypes, a former relapse or nonresponse, liver transplant recipients and cardiovascular or pulmonary disease is considered insufficient.

Genetic variation of inosine triphosphatase (ITPA) causing an accumulation of inosine triphosphate (ITP) has been shown to protect patients against ribavirin (RBV)-induced anemia during treatment for chronic hepatitis C infection by genome-wide association study (GWAS). However, the biologic mechanism by which this occurs is unknown.

We examined whether ITP can be used by adenosine triphosphatase (ATPase) in human erythrocytes or recombinant human adenylosuccinate synthase (ADSS). RBV-induced adenosine triphosphate (ATP) reduction in erythrocytes was compared with the genetically determined low or normal activity of ITPA, leading respectively to high or normal ITP levels.

Although ITP is not used directly by human erythrocyte ATPase, it can be used for ATP biosynthesis via ADSS in place of guanosine triphosphate (GTP). With RBV challenge, erythrocyte ATP reduction was more severe in the wild-type ITPA genotype than in the hemolysis protective ITPA genotype. This difference also remains after inhibiting adenosine uptake using nitrobenzylmercaptopurine riboside (NBMPR). Interestingly, the alleviation of ATP reduction by the hemolysis protective ITPA genotype was canceled by the ADSS inhibitor 6-mercaptoethanol (6-MP).

ITP confers protection against RBV-induced ATP reduction by substituting for erythrocyte GTP, which is depleted by RBV, in the biosynthesis of ATP. Because patients with excess ITP appear largely protected against anemia, these results confirm that RBV-induced anemia is due primarily to the effect of the drug on GTP and consequently ATP levels in erythrocytes.

Hepatitis C virus-Human immunodeficiency virus (HCV-HIV) coinfections are identified in up to 30% of patients infected with HIV and in 8% of patients infected with HCV. Now that progression of HIV and deaths due to AIDS can be prevented by highly active antiretroviral therapy (HAART), it is clear that HCV coinfection is associated with accelerated progression to cirrhosis and increased liver-related morbidity and mortality. Antiviral therapy with pegylated interferon and ribavirin for HCV in HCV-HIV coinfected patients is less successful than in patients with HCV monoinfection, and HAART can cause drug-induced liver injury. Multiple barriers limit the number of HCV-HIV coinfected patients who receive antiviral therapy for HCV, and the role of orthotopic liver transplantation (OLT) in HIV monoinfected and HCV-HIV coinfected patients remains controversial. Clinical trials of HCV-specific protease or polymerase inhibitors combined with pegylated interferon and ribavirin are needed urgently in coinfected patients, both before and after OLT.

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.

Proteins might act as pronucleating agents of cholesterol crystallization in bile. However, little is known about the redox status of biliary proteins in humans and their interaction with crystallization of biliary cholesterol.

Gallbladder biles were obtained at cholecystectomy from 86 symptomatic patients with either cholesterol gallstones (32 multiple and 32 solitary stones) or pigment stones (n = 22), and studied for protein redox status [carbonyl and sulfhydryl (PSH) concentrations], total lipid and protein levels and cholesterol saturation index (CSI). First appearance of cholesterol crystals in ultrafiltered bile (crystal observation time, COT) was studied with polarizing light microscopy during 21 days.

Patients with cholesterol stones had significantly shorter COT (3 days vs. >21 days, P < 0.05), higher CSI (149 +/- 10% vs. 97 +/- 7%, P < 0.05) and higher total biliary proteins (1.96 +/- 0.1 mg mL(-1) vs. 0.55 +/- 0.1 mg mL(-1), P < 0.05) than patients with pigment stones. Patients with cholesterol stones had significantly lower (P < 0.05) level of protein sulfhydryl concentrations (18 +/- 4 nmol mg(-1) protein vs. 49 +/- 16 nmol mg(-1) protein), while total lipid and carbonyl proteins concentrations were similar between cholesterol and pigment stone patients. Crystallization probability was influenced by the number/type of gallstones (multiple > solitary > pigment stones, P = 0.009) and total protein concentration (high > low levels, P = 0.004). COT was negatively correlated with total protein content (r = -0.45, P = 0.03).

Biles with cholesterol stones show high CSI and total protein concentration, and rapid COT, which is even faster in patients with multiple stones and high protein concentration. Low PSH levels in cholesterol stone patients point to a biochemical shift, potentially able to affect cholesterol crystallization.

Drug-induced liver injury is a significant and still unresolved clinical problem. Limitations to knowledge about the mechanisms of toxicity render incomplete the detection of hepatotoxic potential during preclinical development. Several xenobiotics are lipophilic substances and their transformation into hydrophilic compounds by the cytochrome P-450 system results in production of toxic metabolites. Aging, preexisting liver disease, enzyme induction or inhibition, genetic variances, local O(2) supply and, above all, the intrinsic molecular properties of the drug may affect this process. Necrotic death follows antioxidant consumption and oxidation of intracellular proteins, which determine increased permeability of mitochondrial membranes, loss of potential, decreased ATP synthesis, inhibition of Ca(2+)-dependent ATPase, reduced capability to sequester Ca(2+) within mitochondria, and membrane bleb formation. Conversely, activation of nucleases and energetic participation of mitochondria are the main intracellular mechanisms that lead to apoptosis. Non-parenchymal hepatic cells are inducers of hepatocellular injury and targets for damage. Activation of the immune system promotes idiosyncratic reactions that result in hepatic necrosis or cholestasis, in which different HLA genotypes might play a major role. This review focuses on current knowledge of the mechanisms of drug-induced liver injury and recent advances on newly discovered mechanisms of liver damage. Future perspectives including new frontiers for research are discussed.

Although the biochemical steps linking insulin resistance with the metabolic syndrome have not been completely clarified, mounting experimental and clinical evidence indicate oxidative stress as an attractive candidate for a central pathogenic role since it potentially explains the appearance of all risk factors and supports the clinical manifestations. In fact, metabolic syndrome patients exhibit activation of biochemical pathways leading to increased delivery of reactive oxygen species, decreased antioxidant protection and increased lipid peroxidation. The described associations between increased abdominal fat storage, liver steatosis and systemic oxidative stress, the diminished concentration of nitric oxide derivatives and antioxidant vitamins and the endothelial oxidative damages observed in subjects with the metabolic syndrome definitively support oxidative stress as the common second-level event in a unifying pathogenic view. Moreover, it has been observed that oxidative stress regulates the expression of genes governing lipid and glucose metabolism through activation or inhibition of intracellular sensors. Diet constituents can modulate redox reactions and the oxidative stress extent, thus also acting on nuclear gene expression. As a consequence of the food-gene interaction, metabolic syndrome patients may express different disease features and extents according to the different pathways activated by oxidative stress-modulated effectors. This view could also explain family differences and interethnic variations in determining risk factor appearance. This review mechanistically focused on oxidative stress events leading to individual disease factor appearance in metabolic syndrome patients and their setting for a more helpful clinical approach.

The aim of this study was to examine the factors correlated with the progression of ribavirin-induced hemolytic anemia in patients with chronic hepatitis C treated by interferon and ribavirin combination therapy.

This study was conducted on 505 patients by the Osaka Liver Disease Study Group. A decline of hemoglobin (Hb) concentration by 2 g/dl at the end of 2 weeks from the start of the treatment ("2 by 2" standard) was adopted as a predictive factor for progression to severe anemia. The ribavirin apparent clearance (CL/F) was also examined.

Of 482 patients whose Hb value was more than 12 g/dl before the treatment, 68 patients (14%) had to discontinue ribavirin owing to severe anemia. Patients in the "2 by 2"-positive group (Hb decline over 2 g/dl) and the group with lower CL/F were significantly more likely to discontinue ribavirin owing to severe anemia. Discontinuation was more common among patients aged 60 years or older than for those under 60 years old (21% vs. 9%, P < 0.001). Among patients aged 60 years or older, only the "2 by 2" standard was significantly associated with the discontinuance of ribavirin owing to severe anemia in a multivariate analysis (odds ratio, 4.18; P < 0.001).

The "2 by 2" standard of Hb decline can be used to identify patients likely to develop severe anemia. The early reduction of ribavirin can help prevent progression to severe anemia, thus allowing ribavirin therapy to be completed even in older patients.

In previous hepatitis C virus (HCV) treatment studies, Black patients not only had a lower sustained viral response (SVR) rate to interferon and ribavirin (RBV) than non-Black patients but also a higher frequency of HCV genotype 1 (GT-1) infection. The aim of this community-based study was to determine whether Black patients have a lower SVR rate independent of genotype. We prospectively enrolled 785 patients (24.8% Black, 71.5% White, 3.7% others) who received interferon alpha-2b 3 MU three times weekly + RBV 1000-1200 mg/day for 24 weeks (GT-2/3) or 48 weeks (GT-1). Black patients were more commonly infected with GT-1 (86.8%vs 64.8%, P < 0.001) and less frequently had an SVR compared with non-Black patients (8.4%vs 21.6%, P < 0.001). Within GT-1, Black patients had a lower SVR rate than non-Black patients (6.1%vs 14.1%, P = 0.004) but not within GT-2/3 (50.0%vs 36.5%, P = 0.47). Black patients had lower baseline haemoglobin levels (14.8 vs 15.3 g/dL, P < 0.001) and neutrophil counts (2900 vs 4100/mm(3), P < 0.001) and required more frequent dose reductions of RBV (29.8%vs 18.5%, P < 0.001) and interferon (4.7%vs 1.6%, P = 0.012). However, dose reductions were not associated with lower SVR rates while early treatment discontinuations were (2.9%vs 25.7%, P < 0.001). Independent predictors of SVR were GT-1 [odds ratio (OR) 0.33; 95% confidence interval (CI) 0.20-0.55; P < 0.001], Black race (OR 0.45; 95% CI 0.22-0.93; P = 0.030), and advanced fibrosis, stages 3 + 4 (OR 0.53; 95% CI 0.31-0.92; P = 0.023). In conclusion, Black patients infected with HCV GT-1 (but not GT-2/3) have a lower SVR rate than non-Black patients. This is not explained by their lower baseline haemoglobin levels and neutrophil counts that lead to higher rates of ribavirin and interferon dose reductions.

To evaluate the effects of zinc supplementation on serum zinc and copper levels, and the severity of adverse reactions and virologic responses in chronic hepatitis C patients undergoing interferon (IFN)/ribavirin therapy.

Forty subjects were randomly assigned to receive IFN-alpha-2a/ribavirin with or without zinc gluconate for 24 weeks, then a period of 6 months for follow-up. Twenty healthy controls were also enrolled in the study. Blood samples were collected at different time points during therapy and at 6 months after the completion of therapy and were analyzed for zinc and copper levels. The adverse reactions and the virologic responses were also examined accordingly.

Serum zinc levels were significantly lower in chronic hepatitis C patients than in healthy controls and further depressed by IFN/ribavirin treatment. However, serum zinc levels in patients were remediable by zinc supplements. No apparent difference was seen in virologic responses between subjects with or without zinc supplements, but certain adverse side effects associated with the zinc therapy were significantly decreased.

Zinc supplementation may be a complementary therapy in chronic hepatitis C patients to increase the tolerance to IFN-alpha-2a and ribavirin.

Pegylated (PEG)-interferon and ribavirin combination therapy are the standard of care for the treatment of chronic hepatitis C and are associated with a high rate of sustained virologic response. However, there is a high incidence of hematologic side effects with this therapeutic regimen. Hematologic side effects are particularly common; bone marrow suppression caused by interferon may result in neutropenia and thrombocytopenia. Ribavirin is directly toxic to red blood cells and is associated with hemolysis, which is usually dose-related but self-limited. Historically, the traditional management of hematologic side effects of interferon therapy has been dose reduction. However, recent studies have shown that response to therapy is strongly influenced by adherence to optimal doses of interferon and particularly ribavirin. Therefore, there is increasing emphasis on the use of growth factors such as filgrastim and erythropoietin to stimulate bone marrow production of erythrocytes and leukocytes to allow patients to receive the optimal doses of interferon and ribavirin. The incidence, magnitude, and possible mechanisms of hematologic complications associated with interferon and ribavirin are described in this review.