Pioglitazone in chronic hepatitis C not responding to pegylated interferon-alpha and ribavirin

Peroxisome proliferator-activated receptors: Key regulators of tumor progression and growth

One of the main causes of death on the globe is cancer. Peroxisome-proliferator-activated receptors (PPARs) are nuclear hormone receptors, including PPARα, PPARδ and PPARγ, which are important in regulating cancer cell proliferation, survival, apoptosis, and tumor growth. Activation of PPARs by endogenous or synthetic compounds regulates tumor progression in various tissues. Although each PPAR isotype suppresses or promotes tumor development depending on the specific tissues or ligands, the mechanism is still unclear. PPARs are receiving interest as possible therapeutic targets for a number of disorders. Numerous clinical studies are being conducted on PPARs as possible therapeutic targets for cancer. Therefore, this review will focus on the existing and future uses of PPARs agonists and antagonists in treating malignancies. PubMed, Science Direct, and Scopus databases were searched regarding the effect of PPARs on various types of cancers until the end of May 2023. The results of the review articles showed the therapeutic influence of PPARs on a wide range of cancer on in vitro, in vivo and clinical studies. However, further experimental and clinical studies are needed to be conducted on the influence of PPARs on various cancers.

Improved diabetes control, allowing insulin cessation, after direct acting antiviral treatment (DAAT) of hepatitis C

There is a bidirectional relationship between hepatitis C and type 2 diabetes. The risk for developing type 2 diabetes is increased in patients with chronic hepatitis C virus (HCV) infection-with the prevalence of diabetes ranging from 13% to 33%. This is likely underpinned by insulin resistance. Type 2 diabetes may also be a predisposing factor for HCV infection. The new non-interferon-based therapeutic regimens for hepatitis C have transformed care and can eradicate disease. In this report, we show how such a regimen eradicated viral load, improved hepatocellular blood markers and significantly improved dysglycaemia, such that all glucose-lowering medication could be stopped.

Exploration and Development of PPAR Modulators in Health and Disease: An Update of Clinical Evidence

Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors that govern the expression of genes responsible for energy metabolism, cellular development, and differentiation. Their crucial biological roles dictate the significance of PPAR-targeting synthetic ligands in medical research and drug discovery. Clinical implications of PPAR agonists span across a wide range of health conditions, including metabolic diseases, chronic inflammatory diseases, infections, autoimmune diseases, neurological and psychiatric disorders, and malignancies. In this review we aim to consolidate existing clinical evidence of PPAR modulators, highlighting their clinical prospects and challenges. Findings from clinical trials revealed that different agonists of the same PPAR subtype could present different safety profiles and clinical outcomes in a disease-dependent manner. Pemafibrate, due to its high selectivity, is likely to replace other PPARα agonists for dyslipidemia and cardiovascular diseases. PPARγ agonist pioglitazone showed tremendous promises in many non-metabolic disorders like chronic kidney disease, depression, inflammation, and autoimmune diseases. The clinical niche of PPARβ/δ agonists is less well-explored. Interestingly, dual- or pan-PPAR agonists, namely chiglitazar, saroglitazar, elafibranor, and lanifibranor, are gaining momentum with their optimistic outcomes in many diseases including type 2 diabetes, dyslipidemia, non-alcoholic fatty liver disease, and primary biliary cholangitis. Notably, the preclinical and clinical development for PPAR antagonists remains unacceptably deficient. We anticipate the future design of better PPAR modulators with minimal off-target effects, high selectivity, superior bioavailability, and pharmacokinetics. This will open new possibilities for PPAR ligands in medicine.

Insulin resistance does not impair response of chronic hepatitis C virus to direct-acting antivirals, and improves with the treatment

BACKGROUND

Insulin resistance (IR) is a common complication in chronic hepatitis C virus (HCV) patients. The impact of IR on outcome of therapy with direct antivirals has not been studied.

AIM

The aim was to assess the impact of direct-acting antiviral (DAA) therapy on IR status in chronic HCV patients.

PATIENTS AND METHODS

A total of 511 patients [mean age: 50.7±10.4 years, 29.7% pegylated interferon and ribavirin (RBV) experienced] were enrolled. Patients with uncontrolled diabetes, decompensated liver disease, or previous nonresponse to DAAs were excluded. Homeostatic model assessment (HOMA) was calculated before and 12 weeks after treatment, and IR was defined as HOMA greater than 1.9. Patients were treated according to the treating physician's choice, and received 12 weeks of either ombitasvir/ritonavir/paritaprevir/RBV (n=28); sofosbuvir (SOF)/simeprevir (n=36); SOF/ravidasvir (n=101); SOF/pegylated interferon/RBV (n=192); or 24 weeks of SOF/RBV (n=154).

RESULTS

Most patients received IR pretreatment (80.6%); 51.3% had fibrosis stage F4 and 24.7% had diabetes. A sustained virological response (SVR) at 12 weeks after treatment (SVR12) was achieved in 465 (91%) patients. SVR12 was achieved in 90.5% of patients with IR and in 92.9% of patients without IR (P=0.560), and pretreatment HOMA was not different in responders and nonresponders (P=0.098). The number of patients with IR decreased significantly in patients who achieved an SVR much more than in nonresponders (P<0.0001) and HOMA improved significantly more in patients with SVR than in nonresponders (P=0.001). All treatment protocols were associated with a comparable improvement in HOMA (P=0.101). Predictors of SVR12 included age, platelets, and liver stiffness, but not pretreatment IR.

CONCLUSION

IR does not impair the response of patients with HCV treated with DAAs, and improves significantly in patients who achieve an SVR.

The role of insulin resistance in nonalcoholic steatohepatitis and liver disease development--a potential therapeutic target?

Insulin resistance (IR) is defined by the inability of insulin to exert its metabolic actions, due to impaired activation of intracellular insulin signaling. This condition is caused by genetic defects or by environmental conditions, among which the most common is obesity. Systemic IR determines the development of hepatic fat accumulation, which can progress to nonalcoholic steatohepatitis, cirrhosis and hepatocellular carcinoma, and is a major determinant of liver disease independently of coexisting factors. Therefore, insulin-sensitizing drugs are currently under evaluation to improve steatohepatitis. Indeed, manipulation of nuclear hormone receptors is already under scrutiny for liver disease prevention by amelioration of IR, whereas NOTCH signaling inhibition represents a novel approach. Nevertheless, further research is warranted to better understand the mechanism linking IR to progressive fibrogenesis in the absence of inflammation and to identify novel drug targets.

Hepatitis C and insulin action: An intimate relationship

Chronic hepatitis C virus (HCV) infection has been shown to be linked to a higher prevalence of type 2 diabetes compared with the general population or with patients with chronic hepatitis B infection and diabetes is the most common extra-hepatic manifestation of HCV. The HCV-diabetes association is due to insulin resistance (IR) that occurs early in the course of the disease even in patients without or with minimal fibrosis. The mechanisms for HCV-induced IR are only partly understood and include a direct inhibitory effect of HCV on insulin signaling pathway. IR in chronic HCV results in an increased progression rate of hepatic fibrosis, cirrhosis and hepatocellular carcinoma. Some but not all studies found that IR reduces the response rate to interferon/ribavirin therapy. Whether IR affects the response to the new direct-acting antiviral treatments is still unknown.

Insulin resistance and its consequences in chronic hepatitis C

Chronic hepatitis C (CHC) is generally a slowly progressive disease, but some factors associated with rapid progression have been identified. Hepatitis C virus (HCV) may contribute to a broad spectrum of metabolic disturbances - namely, steatosis, insulin resistance (IR), increased prevalence of impaired glucose tolerance, type 2 diabetes mellitus (T2DM), lipid metabolism abnormalities and atherosclerosis. HCV can directly or indirectly cause both IR and steatosis, but it is still not resolved whether this viral impact bears the same prognostic value as the metabolic counterparts. As the population exposed to HCV ages, the morbidity due to this disease is increasing. The rising epidemic of obesity contributes to higher prevalence of IR and T2DM. Our understanding of the mutual association between both disease states continues to grow, but is still far from complete. This review briefly discusses the most probable mechanisms involved in IR development in the course of CHC. Molecular mechanisms for the direct and indirect influence of HCV on intracellular insulin signaling are described. Subsequently, the consequences of IR/T2DM for disease progression and management are summarized.

Impact of Body Weight Reduction via Diet and Exercise on the Anti-Viral Effects of Pegylated Interferon Plus Ribavirin in Chronic Hepatitis C Patients with Insulin Resistance: A Randomized Controlled Pilot Trial

OBJECTIVE

Insulin resistance (IR) modifies the anti-viral effects of interferon (IFN) therapy in patients with chronic hepatitis C (CHC). This prospective study evaluated whether lifestyle interventions improve the anti-viral response to treatment with pegylated (PEG)-IFN plus ribavirin (RBV) in patients with CHC.

METHODS

The study cohort consisted of 60 patients chronically infected with a high viral load of hepatitis C virus genotype 1b and a homeostasis model assessment of IR (HOMA-IR) value above 2. The patients were divided into two groups, an intervention group (n=26) and a control group (n=34). The patients in the intervention group were prescribed diet and exercise treatment for 3-6 months to reduce their body weight by ≥5% before starting treatment with PEG-IFN plus RBV.

RESULTS

Diet and exercise significantly reduced the HOMA-IR values in the intervention group, from 3.4 to 2.5 (p=0.0009), especially among the 15 patients who achieved a body weight reduction of ≥5%. The viral disappearance rate at 12 weeks was significantly higher in the intervention group among the patients with a ≥5% weight reduction than in the control group (53.3% vs. 23.5%, p=0.01). However, the sustained viral response (SVR) rates were similar.

CONCLUSION

Improvements in IR achieved through weight reduction via lifestyle interventions may enhance the early viral response to PEG-IFN plus RBV in patients with CHC. However, this intervention program has no effect on the SVR rate.

Metabolic syndrome in chronic hepatitis C infection: does it still matter in the era of directly acting antiviral therapy?

Metabolic syndrome is prevalent in patients with hepatitis C virus (HCV) infection. Given the pandemic spread of HCV infection and metabolic syndrome, the burden of their interaction is a major public health issue. The presence of metabolic syndrome accelerates the progression of liver disease in patients with HCV infection. New drug development in HCV has seen an unprecedented rise in the last year, which resulted in better efficacy, better tolerance, and a shorter treatment duration. This review describes the underlying mechanisms and clinical effects of metabolic syndrome in HCV infection, as well as their importance in the era of new directly acting antiviral therapy.

Does telaprevir possess a direct antidiabetic effect?

Hepatitis C virus (HCV) induces insulin resistance, which improves upon viral clearance. Telaprevir is a protease inhibitor effective against HCV genotype 1. We reported a case, whose history suggests that telaprevir may induce some antidiabetic effect independently of its suppression of HCV. A 56-year-old woman with obesity, type 2 diabetes treated with sitagliptin and metformin, and HCV-related cirrhosis was given triple therapy with pegylated interferon-alpha, ribavirin and telaprevir. After 2 weeks of treatment, HCV RNA was no longer detectable but the patient described a pronounced drop in the capillary glucose levels and episodes of hypoglycaemia that compelled her to stop all antidiabetic treatment. One month after stopping telaprevir, she had to resume her antidiabetic treatment, despite a persisting virological response. Despite reaching a sustained virological response, her diabetes progressed. Although the suppression of HCV replication may have played a role in reducing glucose intolerance, the fact that this patient resumed her prior antidiabetic treatment upon completing the telaprevir treatment, while still aviremic, suggests that telaprevir may have an additional antidiabetic effect. Further evidence about the possible role and mechanisms of telaprevir as antidiabetic agent is warranted.

Hepatitis C virus and metabolic disorder interactions towards liver damage and atherosclerosis

Hepatitis C virus (HCV) is one of the main causes of liver disease worldwide, and alterations of glucose metabolism have reached pandemic proportions in western countries. However, the frequent coexistence between these two conditions is more than simply coincidental, since HCV can induce insulin resistance through several mechanisms. Indeed, the virus interferes with insulin signaling both directly and indirectly, inducing the production of pro-inflammatory cytokines. Furthermore, the entire viral life cycle has strict interconnections with lipid metabolism, and HCV is responsible for a "viral" steatosis which is frequently superimposed to a "metabolic" one. Several evidences suggest that HCV-induced metabolic disorders contribute both to the evolution of liver fibrosis and, likely, to the progression of the other disorders which are typically associated with altered metabolism, in particular atherosclerosis. In the present review, we will examine in depth the links between HCV infection and insulin resistance, liver steatosis and diabetes, and analyze the impact of these interactions on the progression of liver fibrosis and atherosclerosis. Special attention will be focused on the highly debated topic of the relationship between HCV infection and cardiovascular disease. The available clinical literature on this item will be broadly reviewed and all the mechanisms possibly implied will be discussed.

Pilot study of pioglitazone before HCV retreatment in HIV/HCV genotype 1-infected subjects with insulin resistance and previous nonresponse to peginterferon and ribavirin therapy: A5239

: Insulin resistance is associated with nonresponse to hepatitis C virus (HCV) treatment. In this multicenter, single-arm pilot study, adult, HIV/HCV genotype 1-coinfected previous nonresponders to peginterferon/ribavirin (PegIFN/RBV) with homeostatic model assessment of insulin resistance >2.5 were treated with pioglitazone (PIO) for 24 weeks followed by PegIFN/RBV/PIO. Three of 19 subjects (15.8%) achieved undetectable HCV RNA at week 24 of PegIFN/RBV/PIO, which was not significantly different than the historical null rate of 10% (P = 0.29, lower limit of the exact 1-sided 90% confidence interval 5.9%). Over the 24 weeks of PIO monotherapy, alanine aminotransferase and aspartate aminotransferase declined significantly and correlated with improved metabolic parameters.

Hepatitis C virus infection and insulin resistance

Approximately 170 million people worldwide are chronically infected with hepatitis C virus (HCV). Chronic HCV infection is the leading cause for the development of liver fibrosis, cirrhosis, hepatocellular carcinoma (HCC) and is the primary cause for liver transplantation in the western world. Insulin resistance is one of the pathological features in patients with HCV infection and often leads to development of type II diabetes. Insulin resistance plays an important role in the development of various complications associated with HCV infection. Recent evidence indicates that HCV associated insulin resistance may result in hepatic fibrosis, steatosis, HCC and resistance to anti-viral treatment. Thus, HCV associated insulin resistance is a therapeutic target at any stage of HCV infection. HCV modulates normal cellular gene expression and interferes with the insulin signaling pathway. Various mechanisms have been proposed in regard to HCV mediated insulin resistance, involving up regulation of inflammatory cytokines, like tumor necrosis factor-α, phosphorylation of insulin-receptor substrate-1, Akt, up-regulation of gluconeogenic genes like glucose 6 phosphatase, phosphoenolpyruvate carboxykinase 2, and accumulation of lipid droplets. In this review, we summarize the available information on how HCV infection interferes with insulin signaling pathways resulting in insulin resistance.

The impact of obesity and metabolic syndrome on chronic hepatitis C

The metabolic syndrome and the hepatitis C virus (HCV) infection are 2 global health care challenges with a complex interaction. Insulin resistance, a central component of the metabolic syndrome, is epidemiologically and pathophysiologically intrinsically linked to HCV infection. Insulin resistance and diabetes affect clinical outcomes in patients with liver disease related to HCV, namely, incidence of hepatocellular carcinoma, liver-related mortality, fibrosis progression rate, response to antiviral therapy, and possibly the incidence of cardiovascular events. Viral and metabolic steatosis and its interactions with HCV and the metabolic syndrome are discussed. Management and the need for further research conclude the article.

Hepatitis C and lipid metabolism, hepatic steatosis, and NAFLD: still important in the era of direct acting antiviral therapy?

Chronic hepatitis C (CHC) and nonalcoholic fatty liver disease (NAFLD) have an individual prevalence of 1.8-3% and at least 30%, respectively, in the United States. It is therefore not surprising that there is overlap between these two common chronic liver diseases, although the relationship appears to go beyond isolated co-existence. Hepatic steatosis is a common feature of CHC infection and can be related to both metabolic and viral specific factors. Steatosis in the setting of nongenotype 3 CHC has been predictive of response to therapy prior to the advent of the direct acting antiviral medications (DAAs). Similarly, lipid metabolism appears important in response to CHC treatment. The pathways for both lipid homeostasis and NAFLD as it pertains to CHC infection as well as the utilization of statin therapy in CHC infection will be reviewed with a focus on the relevance of these topics in the era of DAA therapy.

Homeostasis model assessment of insulin resistance does not seem to predict response to telaprevir in chronic hepatitis C in the REALIZE trial

Baseline homeostasis model assessment-estimated insulin resistance (HOMA-IR), a marker for insulin resistance, has been associated with poor virologic response to peginterferon alpha/ribavirin (PR) in chronic hepatitis C. We evaluated the association between baseline HOMA-IR and pretreatment factors on sustained virologic response (SVR) to telaprevir (TVR) in genotype 1 patients with hepatitis C and prior peginterferon/ribavirin (PR) treatment failure. Patients were randomized to 12 weeks of TVR (750 mg q8h) plus peginterferon (180 μg/week) and ribavirin (1,000-1,200 mg/day) (with or without a 4-week lead-in) followed by PR, or PR alone (PR48), for 48 weeks. Univariate and multiple logistic regression analyses explored the prognostic significance of baseline HOMA-IR alone and adjusted for other pretreatment factors and SVR. The TVR arms were pooled for the purposes of this analysis. In all, 662 patients were randomized; 578 had baseline HOMA-IR and other prognostic data and were included in this analysis. Median baseline HOMA-IR was 2.6 (interquartile range [IQR] 1.7-4.3); 207 (36%), 206 (36%), and 165 (29%) patients had baseline HOMA-IR <2, 2 to <4, and ≥ 4, respectively. Male gender, higher body mass index, triglycerides, gamma-glutamyl transpeptidase, maximum alanine aminotransferase/aspartate aminotransferase, and fibrosis stage were associated with higher baseline HOMA-IR. Baseline HOMA-IR was associated with SVR in univariate analysis, but not after adjustment for other baseline prognostic factors (TVR: OR = 0.95, 95% confidence interval [CI]: 0.71,1.29; PR48: 0.60; 95% CI: 0.25,1.43).

CONCLUSION

In patients with prior PR treatment failure, baseline HOMA-IR correlated with SVR in univariate but not multivariate analyses, suggesting other factors have a more direct causal relationship with virologic response to TVR-based therapy than HOMA-IR.

Insulin resistance, steatosis and hepatitis C virus

Epidemiological studies have shown an increased occurrence of metabolic disorders such as insulin resistance (IR) and steatosis in patients with hepatitis C virus (HCV) infection. IR is believed to represent one of the central clinical features of the "metabolic syndrome" and the major pathogenetic factor for type 2 diabetes mellitus. In patients with chronic HCV hepatitis, IR may have several dangerous consequences such as accelerated progression of liver fibrosis, resistance to antiviral therapy and development of hepatocellular carcinoma. According to recent evidence, the global epidemic of metabolic disorders related to incorrect diets will lead physicians to deal with 1.2 billion patients with diabetes in the world in 2025. Given the high prevalence of HCV infection in several countries, metabolic manifestations will contribute to increasing morbidity and mortality in patients with HCV chronic infection in the near future. HCV treatment, shown able to decrease both the occurrence of HCV-related IR and diabetes, may reduce the risk of the associated morbidities.

Glucose abnormalities in hepatitis C virus infection

Hepatitis C virus (HCV) infection is one of the most important causes of cirrhosis and hepatocellular carcinoma and has a tremendous impact on public health worldwide. HCV is both hepatotropic and lymphotropic. Replication of HCV in diseased extrahepatic organs and tissues may either trigger latent autoimmunity or induce autoimmune disorders. In addition to established liver injury, type 2 diabetes mellitus (T2DM) is an important feature of extrahepatic metabolic disorders which is attributed to HCV infection. It also has some impact on the disease activity, disease course, clinical outcomes, and treatment efficacy of antiviral therapy. Previous experimental and clinical findings have highly suggested that HCV per se is diabetogenic. The cause-effect interaction between a common endocrine disorder and an infectious disease is an important issue to elucidate. Although the precise mechanisms whereby HCV infection leads to insulin resistance (IR) and glucose abnormalities are not entirely clear, it differs from the usual pathogenesis of T2DM in those with non-HCV liver diseases. This review initially highlights epidemiological and pathophysiological studies addressing the mutual link between chronic HCV infection (CHC) and T2DM. The characteristics of glucose abnormalities in this special population are depicted from the current evidence. The mutual roles of IR and CHC with respect to the prediction of treatment efficacy, how treatment response affects IR, and the role of pancreatic beta cell function in the entire suite are discussed. With the rapid progression of antiviral therapy for CHC in the past decade, we have also listed some points of future perspective in this issue.

PPARs Signaling and Cancer in the Gastrointestinal System

Nowadays, the study of the peroxisome proliferators activated receptors (PPARs) as potential targets for cancer prevention and therapy has gained a strong interest. From a biological point of view, the overall responsibility of PPARs in cancer development and progression is still controversial since several studies report both antiproliferative and tumor-promoting actions for these signaling molecules in human cancer cells and animal models. In this paper, we discuss PPARs functions in the context of different types of gastrointestinal cancer.

Chronic hepatitis C genotype 1 patients with insulin resistance treated with pioglitazone and peginterferon alpha-2a plus ribavirin

Patients with chronic hepatitis C and insulin resistance are less likely to respond to anti-hepatitis C virus (HCV) therapy and are at risk for more rapid fibrosis progression. Coadministration of pioglitazone with peginterferon/ribavirin improves insulin sensitivity and increases virologic response rates in insulin-resistant HCV genotype 4 patients, but it is unclear whether this finding applies to genotype 1 patients. For this reason we randomized treatment-naive HCV genotype 1 patients with insulin resistance to receive either standard care (peginterferon alpha-2a plus ribavirin for 48 weeks, n = 73) or pioglitazone 30-45 mg/day plus standard care (n = 77) in an open-label multicenter trial. Patients randomized to pioglitazone received the drug during a 16-week run-in phase, the 48-week standard-care phase, and the 24-week untreated follow-up phase. Pioglitazone treatment improved hemoglobin A1c (HbA1c), plasma glucose, insulin levels, and homeostasis model assessment of insulin resistance score and increased serum adiponectin levels during the 16-week run-in phase and maintained these improvements during the standard-care phase. However, we observed no statistically significant difference between the two groups in the primary efficacy endpoint, the decrease from baseline to Week 12 of peginterferon alpha-2a/ribavirin treatment in mean log(10) HCV RNA titer (-3.5 ± 1.71 and -3.7 ± 1.62 IU/mL in the pioglitazone and standard-care groups, respectively, Δ = 0.21 IU/mL, P = 0.4394).

CONCLUSION

Treatment with pioglitazone before and during treatment with peginterferon alpha-2a plus ribavirin improved several indices of glycemic control in patients with chronic hepatitis C and insulin resistance, but did not improve virologic response rates compared with peginterferon alpha-2a plus ribavirin alone.

The interaction of metabolic factors with HCV infection: does it matter?

Given the pandemic spread of the hepatitis C virus (HCV) infection and the metabolic syndrome (MS), the burden of their interaction is a major public health issue, bound to increase in the near term. A better appreciation of the clinical consequences of the relationship between HCV and MS is needed, not only due to their potential synergism on liver disease severity, but also because of the multifaceted interactions between HCV and glucose and lipid metabolism. HCV infection per se does not carry an increased risk of MS, but is able to perturb glucose homeostasis through several direct and indirect mechanisms, leading to both hepatic and extrahepatic insulin resistance. This translates into accelerated liver disease progression (including the development of hepatocellular carcinoma), reduced response to antivirals and, in susceptible individuals, increased risk of developing full-blown type 2 diabetes. HCV may also cause hepatic steatosis, especially in patients infected with genotype 3, although the clinical impact of viral steatosis is debated. Possibly as a result of HCV-induced insulin resistance, and despite a paradoxically favourable lipid profile, the cardiovascular risk is moderately increased in chronic hepatitis C. In addition, the interaction with the MS further increases the risks of cirrhosis, hepatocellular carcinoma, diabetes, and cardiovascular events. Thus, targeted lifestyle and pharmacological measures are urgently warranted in chronic hepatitis C with metabolic alterations.

Pioglitazone decreases hepatitis C viral load in overweight, treatment naïve, genotype 4 infected-patients: a pilot study

BACKGROUND

Insulin resistance (IR) is induced by chronic hepatitis C virus (HCV) genotypes 1 and 4 infections. It is not known whether drugs that affect IR such as Pioglitazone and Prednisone also affect serum HCV RNA titers independently of PEG-Interferon-α2/ribavirin treatment. The primary aim was to assess whether Pioglitazone by improving IR and/or inflammation decreases HCV viral load independently of standard of care HCV treatment. A secondary aim was to assess whether Prednisone, a drug that induces insulin resistance and stimulates HCV viral entry and replication in replicon culture systems, increases HCV viral load in this population.

METHODOLOGY/PRINCIPAL FINDINGS

We designed a two-arm, parallel Pilot Study of overweight, treatment naïve genotype 4 HCV-infected patients at a public referral Liver Clinic in Giza, Egypt. The subjects received Pioglitazone (30 mg/day for 14 days) or Prednisone (40 mg/day for 4 days) in a randomized fashion, but the two arms can be considered independent pilot studies. Only changes from baseline within each arm were assessed and no contrasts of the interventions were made, as this was not an aim of the study. Among 105 consecutive HCV genotype 4 patients, 39 were enrolled based on the optimal sample size and power analysis according to the CONSORT statement; 20 to the Pioglitazone group and 19 to the Prednisone group. Pioglitazone was effective in decreasing serum HCV RNA at day-14 (n = 10; difference of means = 205,618 IU/ml; 95% CI 26,600 to 384,600; P<0.001). Although Prednisone did increase serum HCV RNA at day-4 (n = 10; change from baseline = -42,786 IU/ml; 95% CI -85,500 to -15,700; P = 0.049), the log(10) HCV RNA titers were statistically not different from baseline day-0.

CONCLUSION/SIGNIFICANCE

This is the first documentation that Pioglitazone decreases the serum HCV RNA titers independently of PEG-Interferon-α2/ribavirin treatment. The novel findings of our Study provide the foundation for basic and clinical investigations on the molecular mechanisms responsible for the Pioglitazone-induced decrease in HCV genotype 4 RNA titers.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01157975.

Impact of HCV genetic differences on pathobiology of disease

Multiple HCV genotypes have been isolated worldwide. Genotype seems to be involved in the main pathological aspects of HCV infection. Insulin resistance, steatosis and progression toward cirrhosis, fibrosis and hepatocellular carcinoma establish and develop following genotype-specific mechanisms. Moreover genotype influences pharmacological treatment in term of dose and duration. Pathways involved in cell proliferation, apoptosis, lipid metabolism, insulin and interferon signaling are impaired to a different extent among genotypes, leading to distinct pathological settings. Genotype 1 is associated with a more aggressive disease with increased insulin resistance, worst response to therapy, higher risk of cirrhosis and hepatocellular carcinoma development, while genotype 3 is associated with increased steatosis and fibrosis. The identification and characterization of HCV types and subtypes provides insight into the different outcome of HCV infection and responsiveness to therapy. In the present article, we focused on the pathogenicity of HCV genotypes and their effect on disease progression and treatment.

Hepatitis C virus induced insulin resistance impairs response to anti viral therapy

Hepatitis C virus (HCV) infection is an important risk factor for insulin resistance (IR). The latter is the pathogenic foundation underlying metabolic syndrome, steatosis and cirrhosis, and possibly hepatocellular carcinoma (HCC). The interplay between genetic and environmental risk factors ultimately leads to the development of IR. Obesity is considered a major risk factor, with dysregulation of levels of secreted adipokines from distended adipose tissue playing a major role in IR. HCV-induced IR may be due to the HCV core protein inducing proteasomal degradation of insulin receptor substrates 1 and 2, blocking intracellular insulin signaling. The latter is mediated by increased levels of both tumour necrosis factor-α (TNF-α) and suppressor of cytokine signaling 3 (SOC-3). IR, through different mechanisms, plays a role in the development of steatosis and its progression to steatohepatitis, cirrhosis and even HCC. In addition, IR has a role in impairing TNF signaling cascade, which in turn blocks STAT-1 translocation and interferon stimulated genes production avoiding the antiviral effect of interferon.

Metabolic disorders and steatosis in patients with chronic hepatitis C: metabolic strategies for antiviral treatments

It has been reported that hepatitis C virus (HCV) infection is closely associated with hepatic metabolic disorders. Hepatic steatosis and insulin resistance are both relatively common in patients with chronic hepatitis C. Recent investigations suggest that HCV infection changes the expression profile of lipid-metabolism-associated factors in the liver, conferring advantages to the life cycle of HCV. Moreover, insulin resistance and steatosis are independent predictors of impaired response to antiviral treatment in chronic hepatitis C. In this paper, we summarize our current knowledge of hepatic metabolic disorders and describe how HCV leads to and exploits these hepatic disorders. We also discuss the clinical significance of insulin sensitizers used to improve insulin resistance and lipid modulators used to manage lipid metabolism as potential treatment options for chronic hepatitis C.

Steatosis and insulin resistance in response to treatment of chronic hepatitis C

This review will focus on the impact of steatosis and insulin resistance on the response to antiviral therapy for chronic hepatitis C. Hepatitis C virus (HCV) infection is known to have direct and/or indirect effects on lipid and glucose metabolism, leading to, among other disturbances, steatosis and insulin resistance, respectively. Some of these disturbances have a marked HCV genotype distribution. For example, on average, patients with HCV genotype 3 have the highest prevalence and severity of viral fatty liver. On the other hand, the current global spread of the metabolic syndrome represents a formidable cofactor of morbidity in HCV-related chronic liver disease. Thus, the pathogenesis of steatosis and insulin resistance in patients with chronic hepatitis C may often be dual, i.e. viral and metabolic. This distinction is relevant because the effect (if any) of steatosis or insulin resistance on the response to antiviral agents seems to depend on their pathogenesis. Accumulating data suggest that viral fatty liver may not impact on response to therapy, while metabolic steatosis does. Similarly, viral insulin resistance may not reduce the rate of response to therapy to the same extent that metabolic insulin resistance does. Some implications for patient management are discussed.

HCV and the hepatic lipid pathway as a potential treatment target

Atherosclerosis has been described as a liver disease of the heart [1]. The liver is the central regulatory organ of lipid pathways but since dyslipidaemias are major contributors to cardiovascular disease and type 2 diabetes rather than liver disease, research in this area has not been a major focus for hepatologists. Virus-host interaction is a continuous co-evolutionary process [2] involving the host immune system and viral escape mechanisms [3]. One of the strategies HCV has adopted to escape immune clearance and establish persistent infection is to make use of hepatic lipid pathways. This review aims to: • update the hepatologist on lipid metabolism • review the evidence that HCV exploits hepatic lipid pathways to its advantage • discuss approaches to targeting host lipid pathways as adjunctive therapy.

Peroxisome proliferator-activated receptors and hepatitis C virus

The prevalence of type 2 diabetes mellitus and insulin resistance are higher among people chronically infected with hepatitis C (CHC) when compared with the general population and people with other causes of chronic liver disease. Both insulin resistance and diabetes are associated with adverse outcomes across all stages of CHC, including the liver transplant population. CHC is also associated with the development of hepatic steatosis, a common histological feature present in approximately 55% (32-81%) of cases. There is a complex interrelationship between insulin resistance and hepatic steatosis and both are postulated to aggravate each other. The peroxisome proliferator-activated receptors (PPARs) are nuclear factors involved in the regulation of glucose, lipid homeostasis, inflammatory response, cell differentiation, and cell cycle. The relationship between hepatitis C virus replication and PPARs has been the focus of recent study. Given the availability of potent agonists, PPARs may represent a novel pharmacological target in the treatment of CHC.

The interaction between HCV and nuclear receptor-mediated pathways

Hepatitis C virus (HCV) is presently the leading indication for liver transplantation in Western countries. Treatment for HCV infection includes a combination of pegylated interferon and ribavirin, which produces highly variable response rates. This reflects the lack of information regarding the roles of host and viral components during viral pathogenesis. Vital processes regulated by the liver, including metabolism, lipid homeostasis, cellular proliferation, and the immune response, are known to be systematically dysregulated as a result of persistent HCV infection. Nuclear receptors and their ligands are recognized as indispensable regulators of liver homeostasis. Pathways mediated by the nuclear receptor superfamily have been shown to be profoundly disrupted during HCV infection, leading to an increased importance in elucidating the exact nature of this complex relationship. Expanded understanding of the role of nuclear receptors in HCV infection may therefore be an essential step in the search for a more universally effective treatment.

Hepatitis C virus-associated insulin resistance: pathogenic mechanisms and clinical implications

It is now widely recognized that chronic hepatitis C is a metabolic disease, strongly associated with Type 2 diabetic mellitus and insulin resistance (IR). Chronic hepatitis C virus (HCV) infection promotes IR mainly through interfering with the insulin signaling pathway in hepatocytes, increasing the inflammatory response with production of cytokines such as TNF-α and IL-6, and increasing oxidative stress. Accumulated evidence indicates that HCV-associated IR may lead to fibrosis progression, resistance to antiviral therapy, hepatocarcinogenesis and extrahepatic manifestations. Thus, HCV-associated IR is a therapeutic target at any stage of HCV infection. However, specific pharmaceutical treatments of IR are still being evaluated in clinical trials, but available data do not warrant their use in all chronic hepatitis C patients with IR.

Current understanding of insulin resistance in hepatitis C

Important breakthroughs have been made in recent years into understanding the close interaction between hepatitis C virus (HCV) infection and glucose homeostasis. Both cross-sectional and longitudinal studies have demonstrated that infection with HCV is associated with an increased risk of developing insulin resistance and Type 2 diabetes. A direct effect of HCV on hepatocyte insulin signaling has been shown in experimental models. Some preliminary observations seem to suggest that indirect mechanisms involving extrahepatic organs might also play a role. The interaction between HCV and glucose metabolism has significant clinical consequences. Insulin resistance and Type 2 diabetes not only accelerate the histological and clinical progression of chronic hepatitis C, but also reduce the virological response to IFN-α-based therapy. Thus, understanding the mechanisms underlying HCV-associated glucose metabolism derangements is of paramount interest in order to improve the clinical management of chronic hepatitis C. This article will focus on the studies that consistently argue in favor of an interrelation between HCV and insulin resistance and will highlight the latest discoveries in this field.

Reciprocal interference between insulin and interferon-alpha signaling in hepatic cells: a vicious circle of clinical significance?

Insulin resistance (IR) is common in chronic hepatitis C (CHC) and associates with reduced virological response to pegylated-interferon (PEG-IFN)/ribavirin therapy, but the underlying mechanisms are still unclear. We have previously shown that, in CHC patients, insulin plasma levels are inversely related to antiviral effect induced by PEG-IFN. Therefore, we investigated the in vitro effect of insulin on interferon alpha (IFN-α) intracellular signaling as well as that of IFN-α on insulin signaling. HepG2 cells, preincubated with or without insulin, were stimulated with IFN-α2b and messenger RNA (mRNA) and protein expression of IFN-stimulated genes (ISGs) were measured at different timepoints. The role of intracellular suppressors of cytokine signaling 3 (SOCS3) was evaluated with the small interfering RNA (siRNA) strategy. To assess the effect of IFN-α on insulin signaling, HepG2 were preincubated with or without IFN before addition of insulin and cells were then analyzed for IRS-1 and for Akt/PKB Ser473 phosphorylation. Insulin (100 and 1000 nM) significantly reduced in a dose-dependent fashion IFN-induced gene expression of PKR (P=0.017 and P=0.0017, respectively), MxA (P=0.0103 and P=0.00186), and 2'-5' oligoadenylatesynthetase 1 (OAS-1) (P=0.002 and P=0.006). Insulin also reduced IFN-α-induced PKR protein expression. Although insulin was confirmed to increase SOCS3 expression, siRNA SOCS3 did not restore ISG expression after insulin treatment. IFN-α was found to reduce, in a dose-dependent fashion, IRS-1 gene expression as well as Akt/PKB Ser473 phosphorylation induced by insulin.

CONCLUSION

These results provide evidence of reciprocal interference between insulin and IFN-α signaling in liver cells. These findings may contribute to understand the role of insulin in CHC: IR might be favored by endogenous cytokines including IFN-α, and the resulting hyperinsulinemia then reduces the antiviral response to exogenous IFN in a vicious circle of clinical significance.

The HIV/HCV-coinfected patient and new treatment options

Hepatitis C (HCV) treatment is on the cusp of change with the approval of the first direct-acting antivirals: telaprevir and boceprevir. Drug-drug interactions with HIV antiretrovirals, increased toxicity, and rapid selection of HCV-resistant mutants are among the treatment complexities expected in this difficult-to-treat population. Until the current standard of care changes, focus should be on strategies to optimize management of HIV/HCV-coinfected patients with currently available options. This article reviews the latest predictive factors of response to HCV treatment with the current standard of care in HIV-coinfected patients, and new treatment options.

The role of lifestyle changes in the management of chronic liver disease

The prevalence of obesity worldwide has dramatically increased during the last three decades. With obesity comes a variety of adverse health outcomes which are grouped under the umbrella of metabolic syndrome. The liver in particular seems to be significantly impacted by fat deposition in the presence of obesity. In this article we discuss several liver conditions which are directly affected by overweight and obese status, including non-alcoholic fatty liver disease, chronic infection with hepatitis C virus and post-liver transplant status. The deleterious effects of obesity on liver disease and overall health can be significantly impacted by a culture that fosters sustained nutritional improvement and regular physical activity. Here we summarize the current evidence supporting non-pharmacological, lifestyle interventions that lead to weight reduction, improved physical activity and better nutrition as part of the management and treatment of these liver conditions.

Insulin resistance and chronic liver disease

Increased insulin resistance is frequently associated with chronic liver disease and is a pathophysiological feature of hepatogenous diabetes. Distinctive factors including hepatic parenchymal cell damage, portal-systemic shunting and hepatitis C virus are responsible for the development of hepatogenous insulin resistance/diabetes. Although it remains unclear whether insulin secretion from pancreatic beta cells is impaired as it is in type 2 diabetes, retinopathic and cardiovascular risk is low and major causes of death in cirrhotic patients with diabetes are liver failure, hepatocellular carcinoma and gastrointestinal hemorrhage. Hemoglobin A1c is an inaccurate marker for the assessment and management of hepatogenous diabetes. Moreover, exogenous insulin or sulfonylureas may be harmful because these agents may promote hepatocarcinogenesis. Thus, pathogenesis, cause of death, assessment and therapeutic strategy for hepatogenous insulin resistance/diabetes differ from those for lifestyle-related type 2 diabetes. In this article, we review features of insulin resistance in relationship to chronic liver disease. We also discuss the impact of anti-diabetic agents on interferon treatment and hepatocarcinogenesis.

Mechanisms of hepatitis C virus-related insulin resistance

The hepatitis C virus (HCV) infection has been shown to have direct and/or indirect effects on glucose metabolism, leading to insulin resistance and, in predisposed individuals, type 2 diabetes. This is supported by several experimental, clinical and epidemiological data. The detailed molecular events leading to insulin resistance in HCV-infected patients are unclear. HCV infects primarily the liver and, to a very minor extent, mononuclear cells. Direct interactions between HCV products and the hepatocyte insulin signaling pathway have been reported by several authors. However, recent evidence supports the existence of a significant extrahepatic component of HCV-induced insulin resistance. Thus, the molecular pathogenesis of glucose metabolism disturbances observed in hepatitis C is much more complex than expected. The clinical management of such condition remains empirical.

The homeostasis model assessment of the insulin resistance score is not predictive of a sustained virological response in chronic hepatitis C patients

OBJECTIVES

To investigate the independent association between the homeostasis model assessment of the insulin resistance (HOMA-IR) score and rapid virological response (RVR) and sustained virological response (SVR) in chronic hepatitis C (CHC).

METHODS

Observational prospective cohort study of 412 CHC patients [59% males; mean age 45 years; genotype 1 (44%), 2 (32%), 3 (19%) and 4 (5%)] treated with pegylated interferon α plus ribavirin.

RESULTS

A HOMA-IR ≥2.0 was present in 49% and a metabolic syndrome in 4% of patients. By multivariate analysis, independent predictors of SVR were the lack of advanced fibrosis (≥F3) in genotype 1 and a lower body mass index in genotype 3 patients. In the subgroup of patients in whom HCV-RNA was evaluated at week 4 (n = 281), independent predictors of RVR were HCV-RNA <700,000 IU/ml, age <40 years and lower aspartate aminotransferase:alanine aminotransferase ratio in genotype 1 and baseline HOMA-IR ≤2 in genotype 3 patients. No predictive factor of RVR was identified among genotype 2 patients. RVR was the strongest predictor of SVR among genotype 1 or 3 patients.

CONCLUSIONS

In this series of treatment-naïve, Caucasian CHC patients at a low risk for the metabolic syndrome, HOMA-IR is not a predictor of SVR, irrespective of the HCV genotype, although it may predict RVR in genotype 3 infection.

Insulin resistance predicts re-treatment failure in an efficacy study of peginterferon-α-2a and ribavirin in HIV/HCV co-infected patients

BACKGROUND & AIMS

Few studies evaluated the efficacy of HCV re-treatment and the predictors of response in HIV/HCV co-infected patients. The role of insulin resistance as a predictor of response in this population is unknown. The aim of this study is to evaluate the safety and efficacy of pegylated interferon-α-2a and ribavirin in re-treatment of HIV/HCV co-infected patients, predictors of sustained virological response, including insulin resistance, and the relationship between insulin resistance and liver histology.

METHODS

This prospective, multi-centered study included HIV/HCV co-infected patients with prior interferon-based treatment failure. Patients received pegylated interferon-α-2a and ribavirin for 48 weeks. Serum HCV RNA was measured 24 weeks post treatment to assess sustained virological response. Insulin resistance was defined as HOMA-IR >2. Correlations between baseline insulin resistance and steatosis, and/or cirrhosis were determined.

RESULTS

Sustained virological response was achieved in 14/96 (15%) patients. 35% of patients with HOMA-IR < 2 (6/17) achieved sustained virological response vs 14% (5/36) of those with HOMA-IR between 2-4, and 7% (3/41) of those with HOMA-IR > 4 (p = 0.01). In multivariable analysis, insulin resistance and log₁₀ HCV RNA were negatively associated with sustained virological response [AOR 0.17; 95% CI 0.05-0.64, p = 0.009, and AOR 0.36; 95% CI 0.14-0.93, p = 0.04, respectively]. Steatosis and cirrhosis correlated with insulin resistance (p = 0.02 and 0.03, respectively) but neither independently predicted sustained virological response. Discontinuations due to severe adverse events occurred in 8% of cases, and 2 patients died of unrelated causes.

CONCLUSIONS

In HIV/HCV co-infected patients undergoing re-treatment, sustained virological response rate is low; those patients without insulin resistance are significantly more likely to achieve sustained virological response.

Statin therapy improves sustained virologic response among diabetic patients with chronic hepatitis C

BACKGROUND & AIMS

Patients with chronic hepatitis C infection are 2- to 3-fold more likely to develop type 2 diabetes, which reduces their chances of achieving a sustained virologic response (SVR). To identify differences in predictors of SVR in patients with and without diabetes who received combination antiviral therapy, we conducted a retrospective analysis of a national Veterans Affairs administrative database.

METHODS

We analyzed data from the Veterans Affairs Medical SAS Datasets and Decision Support System for entire cohort and separately for diabetic patients (n = 1704) and nondiabetic patients (n = 6589). Significant predictors of SVR were identified by logistic regression analysis.

RESULTS

Diabetic patients had a lower SVR compared with nondiabetic patients (21% vs 27%, respectively, P < .001). Diabetic patients had higher clustering of previously established negative predictors of SVR. On multivariate analysis of diabetic patients for SVR, the positive predictors were higher low-density lipoprotein (odds ratio [OR], 1.45; P = .0129), use of statin (OR, 1.52; P = .0124), and lower baseline viral load (OR, 2.31; P < .001), whereas insulin therapy (OR, 0.7; P = .0278) was a negative predictor. Diabetic patients on statins had higher pretreatment viral loads (log 6.2 vs 6.4, respectively, P = .006) but better early virologic response. There was a graded inverse relationship between Hemoglobin A1c and SVR rate (P = .0482). This relationship was significant among insulin users (P = .0154) and non-significant among metformin users (P = .5853).

CONCLUSIONS

Statin use was associated with an improved SVR among both diabetic patients and nondiabetic patients receiving combination antiviral therapy. Diabetic patients who received insulin achieved lower SVR compared with those not receiving insulin. Poor diabetes control was associated with lower SVR rates.

Hyperinsulinaemia reduces the 24-h virological response to PEG-interferon therapy in patients with chronic hepatitis C and insulin resistance

Insulin resistance (IR) reduces response to pegylated-interferon (PEG-IFN)/ribavirin in chronic hepatitis C (CHC), but the mechanisms are still undefined. We examined the relationship between baseline insulin levels, the main component affecting homeostasis model of assessment - insulin resistance (HOMA-IR) for assessment of IR in non-diabetic patients, and the 'acute' virological response to PEG-IFN measured 24 h after the first injection and taken as correlate of intracellular interferon signalling. In 62 patients treated with PEG-IFN/Ribavirin, serum insulin and HOMA-IR were assessed at baseline, while hepatitis C virus (HCV)-RNA was measured at baseline and 24 h, 1, 2, 4 and 12 weeks after treatment initiation. Sustained virological response was examined 24 weeks after therapy discontinuation. Mean baseline insulin was 11.52 +/- 8.51 U/L and mean HOMA-IR was 2.65 +/- 2.01 both being significantly higher with advanced liver fibrosis. Hepatitis C virus-RNA decay observed 24 h after the first injection of PEG-IFN was significantly lower (0.7 +/- 0.8 log) in patients with HOMA > or =3 compared with those with HOMA <3 (1.7 +/- 0.8, P = 0.001). A highly significant (r = -0.42) inverse correlation was observed between baseline insulin levels and the 24-h HCV-RNA decay. The difference in early viral kinetics between patients with HOMA > or =3 or <3 resulted in a significant difference in the percentage of patients achieving rapid (week 4) and sustained virological response. Multivariate analysis, inclusive of patient age, HCV genotype and fibrosis stage, identified baseline insulin levels as the main independent variable affecting the 24-h response to PEG-IFN. Hyperinsulinaemia reduces the cellular response to Pegylated-interferon in CHC with IR. Strategies to reduce insulin levels before initiation of treatment should be pursued to improve efficacy of anti-viral treatment.

Hepatitis C virus core protein genotype 3a increases SOCS-7 expression through PPAR-{gamma} in Huh-7 cells

Hepatitis C virus (HCV) core protein genotype 3a induces the expression of suppressor of cytokine signalling protein 7 (SOCS-7), which is partially involved in the development of insulin resistance. The aim of the present study was to investigate the mechanism through which the core protein regulates SOCS-7 expression. We have explored, in the in vitro model of Huh-7 cells expressing the HCV core protein of genotype 3a, whether the expression of SOCS-7 as well as of other members of the SOCS family (SOCS-1 and SOCS-3) was activated by the STAT3 pathway, using immunoblotting and real-time PCR upon alpha interferon (IFN-alpha) treatment. We found that, whilst IFN-alpha treatment induced STAT3 activation and consequently SOCS-1 and SOCS-3 upregulation in HCV genotype 3a core-expressing Huh-7 cells, SOCS-7 mRNA expression was independent of STAT3 and seemed to be modulated by peroxisome proliferator-activated receptor gamma (PPAR-gamma) activity, as demonstrated by quantitative real-time PCR and immunoblot detection after treatment with the PPAR-gamma agonist rosiglitazone or the PPAR-gamma antagonist GW9262. In contrast to the other studied members of the SOCS family (1 and 3), which are regulated by STAT3 activation, SOCS-7 expression appears to be STAT3-independent and seems to be regulated instead by PPAR-gamma. This is the first report proposing a molecular mechanism through which the HCV core protein (genotype 3a) modulates SOCS-7 expression.

[Hepatitis C and metabolic syndrome]

Insulin resistance is a predictive factor of response to treatment with peginterferon and ribavirin in patients with hepatitis C. Insulin resistance impairs sensitivity to interferon and can block its intracellular signalling. Insulin resistance also induces the development of steatosis, progression of fibrosis and proinflammatory cytokine release and reduces the bioavailability of interferon. Suppressor of cytokine signalling 3 and protein tyrosine phosphatases are involved in blocking the intracellular signalling of interferon and insulin. Insulin resistance can be treated through diet, physical exercise and the use of insulin-sensitizing agents such as biguanides or glitazones. The TRIC-1 study demonstrated that adding metformin to routine treatment improves the possibilities of cure in women and in patients whose insulin sensitivity returns to normal during treatment.

Whole-body insulin sensitivity index is a highly specific predictive marker for virological response to peginterferon plus ribavirin therapy in chronic hepatitis C patients with genotype 1b and high viral load

Insulin resistance is a candidate predictive factor for virological response to peginterferon plus ribavirin (PEG/RBV) therapy in chronic hepatitis C patients. We examined whether indices of insulin resistance could serve as a predictor of sustained virological response (SVR). Fifty-one patients with genotype 1b and high viral load who received PEG/RBV therapy for 48 weeks were included. Homeostasis model assessment of insulin resistance (HOMA-IR) and whole-body insulin sensitivity index (WBISI) calculated from the 75-g oral glucose tolerance test and serum levels of soluble tumor necrosis factor receptor 2 (sTFNR2) were evaluated before therapy. Patients who achieved SVR had significantly lower HOMA-IR and sTNFR2 levels and a higher WBISI compared with non-SVR patients. The positive predictive value for SVR was 0.653 for a HOMA-IR of <2 and 0.846 for a WBISI of 6 or higher. WBISI may serve as a highly specific predictor for SVR in PEG/RBV therapy.

Treatment of insulin resistance with metformin in naïve genotype 1 chronic hepatitis C patients receiving peginterferon alfa-2a plus ribavirin

Insulin resistance affects sustained virological response (SVR) in chronic hepatitis C. To know whether adding metformin to standard antiviral treatment improves SVR, we conducted a prospective, multicentered, randomized, double-blinded, placebo-controlled trial in 19 Spanish hospitals, including 123 consecutive patients with genotype 1 chronic hepatitis C and insulin resistance. Patients were randomized to receive either metformin (arm A; n = 59) or placebo (arm B; n = 64) in addition to peginterferon alfa-2a (180 microg/week) and ribavirin (1000-1200 mg/day). The primary end point was SVR, and secondary endpoints were viral clearance at weeks 12, 24, and 48, and changes in the homeostasis model assessment (HOMA) index over the first 24 weeks. There were no differences between arms at baseline. In the intent-to-treat analysis, SVR was observed in 53% versus 42% in arm A and arm B, respectively (P = NS). In the subgroup analyses, SVR was higher in females (n = 54) receiving metformin: arm A, 58% (15/26) versus 29% (8/28) arm B (P = 0.03). In the per protocol analysis (PPA; n = 101), SVR was 67% in arm A and 49% in arm B (P = 0.06). Viral decline during the first 12 weeks was greater in females receiving metformin: -4.88 (1.18) versus -4.0 (1.44) (P = 0.021), whereas no differences were seen in males. The triple therapy was well tolerated, but diarrhea was more often seen in arm A (34% versus 11%; P < 0.05).

CONCLUSION

Adding metformin to peginterferon and ribavirin was safe and improved insulin sensitivity. Although the study failed to show a statistically significant difference between arms, it did show an improved SVR in females.

Insulin resistance predicts rapid virological response in non-diabetic, non-cirrhotic genotype 1 HCV patients treated with peginterferon alpha-2b plus ribavirin

BACKGROUND/AIMS

The rapid decline in hepatitis C virus RNA is crucial for determining the outcome of therapy in patients with genotype 1 chronic hepatitis C. However, the variables influencing the early phase of viral decay are still largely unexplored. We aimed to assess which pre-treatment variable may predict rapid virologic response (RVR) and sustained virologic response (SVR).

METHODS

We evaluated 90 consecutive non-diabetic patients with genotype 1 chronic hepatitis C without cirrhosis, treated with peginterferon alpha-2b plus ribavirin. Viral load (COBAS Amplicore, Roche) was measured at 1, 4 and 12 weeks after starting treatment, and then 24 weeks after the end of treatment.

RESULTS

The overall SVR was 47%. The SVR in patients with RVR was 100%. Age, GGT levels, viral load, steatosis, fibrosis and HOMA-IR were significantly associated with RVR in univariate analysis. After logistic regression, HOMA-IR proved to be the strongest independent predictor of RVR (OR 0.37, 95% CI: 0.16-0.89; p=0.027), whereas fibrosis had a weaker independent association with RVR (OR 0.32, 95% CI: 0.1-1.04; p=0.057). Among the eight pre-treatment variables, both BMI and steatosis were significantly associated with HOMA-IR, either in univariate or in multivariate analyses.

CONCLUSIONS

Our data suggest that insulin resistance is strongly associated with RVR, thus reflecting the important role played by metabolic factors in the early phase of viral kinetics. HOMA-IR would appear to be a useful tool in predicting RVR and should be evaluated at baseline in all chronic hepatitis C patients before initiating antiviral treatment.

Impact of obesity, steatosis and insulin resistance on progression and response to therapy of hepatitis C

Clinical progression of chronic hepatitis C depends on several cofactors, which also have a negative affect on the rate of response to interferon-alpha-based therapy. Given the current worldwide prevalence of the metabolic syndrome, the impact of obesity and insulin resistance, and of their histopathological correlate, hepatic steatosis, on the natural history and management of chronic hepatitis C is undoubtedly very important. We will review some of the current knowledge on the clinical consequences of overweight/obesity, steatosis and insulin resistance on chronic hepatitis C, and discuss how this issue may be dealt with in clinical practice.

Molecular mechanisms of insulin resistance in chronic hepatitis C

It is now widely recognized that chronic hepatitis C (CHC) is associated with insulin resistance (IR) and type 2 diabetes, so can be considered a metabolic disease. IR is most strongly associated with hepatitis C virus (HCV) genotype 1, in contrast to hepatic steatosis, which is associated with genotype 3 infection. Apart from the well-described complications of diabetes, IR in CHC predicts faster progression to fibrosis and cirrhosis that may culminate in liver failure and hepatocellular carcinoma. More recently, it has been recognized that IR in CHC predicts a poor response to antiviral therapy. The molecular mechanisms for the association between IR and HCV infection are not well defined. This review will elaborate on the clinical associations between CHC and IR and summarize current knowledge regarding the molecular mechanisms that potentially mediate HCV-associated IR.