Insulin resistance and HCV: will new knowledge modify clinical management?

Computational Prediction of HCV-Human Protein-Protein Interaction via Topological Analysis of HCV Infected PPI Modules

In this paper, we have developed a framework for detection of protein-protein interactions (PPI) between Hepatitis-C virus (HCV) and human proteins based on PPI and gene ontology based information of the HCV infected proteins. First, a bipartite interaction network is formed between HCV proteins and human host proteins. Next, we have analyzed different topological properties of the interaction network and observed that degree of HCV-interacting proteins is significantly higher than non-interacting host proteins. We have also observed that the HCV interacted protein pairs are functionally similar with each other than the non-interacting pairs. Following the observations, we have applied an inference mechanism to predict novel interactions between HCV and human protein. The inference mechanism is based on partitioning the network formed by HCV interacted human proteins and their first neighbors in dense and functionally similar groups using a PPI network clustering algorithm. The groups are then analyzed to predict PPIs. The predicted interaction pairs are validated using literature search in PUBMED. Experimental evidence of over 50% of the predicted pairs are found in existing literatures by searching PUBMED. A Gene Ontology and pathway based analysis is also carried out to validate the identified modules biologically.

A review of computational approaches for analysis of hepatitis C virus-mediated liver diseases

Chronic infection of hepatitis C virus (HCV) leads to severe life-threatening liver diseases such as cirrhosis of liver, fibrosis and hepatocellular carcinoma (HCC). Severity of the disease infects >180 million people worldwide. In recent years, many computational approaches have been proposed to study and analyze the progression of liver fibrosis, HCC and other liver diseases developed from chronic HCV infection. In this article, we review the literature published in this area of study. Here we categorize all the approaches into two basic groups: analyzing gene expression and studying protein-protein interaction network among HCV-infected human proteins. We also review functional and pathway-enrichment analysis of HCV-interacted human proteins, which gives a clear understanding of functional perturbations leading to hepatocarcinogenesis. Topological analysis of HCV-human protein interaction network and HCV-HCC association network reveals important information of hepatocarcinogenesis progression in liver tissue. We compare the results of topological analysis performed in different studies. Moreover we observe that the HCV-interacted human proteins, which are also responsible for HCC progression, have relatively higher degree and betweenness centrality than that of the other HCV-interacted proteins.

Hepatitis B e antigen-positive and high levels of alanine aminotransferase are associated with prevalence of metabolic syndrome in chronic HBV patients

OBJECTIVE

The interactions between hepatitis B virus (HBV) infection and metabolic syndrome (MS) have not been elucidated. This study was aimed to investigate the relationship between metabolic profile and HBV infection.

METHODS

A retrospective cross-sectional study including patients infected by HBV (HBV group, n=121) and healthy volunteers (control group, n=263) was conducted, serum HBV viral load and markers, serum alanine aminotransferase (ALT) levels and MS were analyzed. Factors associated with prevalence of MS were explored with multivariate adjusted logistic regression analyses.

RESULTS

The prevalence of MS was 9.9% in HBV infected patients and 19.4% in controls (p=0.011). Factors associated with the prevalence of MS were (odds ratio, 95% confidence interval, p value): hepatitis B e antigen (HBeAg) positive (0.368, 0.107-0.653, 0.008) and high levels of ALT (0.183, 0.120-0.268, <0.001) in HBV patients. But clinical and virological factors (including age, HBV DNA level, male gender, BMI, and fatty liver) were not found to be associated with prevalence of MS in HBV patients who were HBeAg positive with high levels of ALT.

CONCLUSION

These findings suggest that HBeAg positive and high levels of ALT are independently associated with lower prevalence of MS in HBV patients. But HBV DNA may not have impact on the lipid metabolism. HBV-related immune reactions may play a certain role in the mechanism of MS.

Insulin resistance and prediabetes in hepatitis C virus patients

BACKGROUND

Egypt has the highest prevalence of hepatitis C virus (HCV) infection in the world and is facing an epidemic of type 2 diabetes mellitus. The objective of this study was to assess the prevalence of insulin resistance (IR) and prediabetes among HCV patients.

METHODS

A cross-sectional case-control study was performed on 188 HCV patients admitted to the Internal Medicine Department in Menoufia University Hospital during the period from May to August 2014. Seventy persons were taken as controls. Body mass index (BMI), serum fasting glucose and fasting insulin were determined. IR was calculated by the Homeostasis Model for Assessment of Insulin Resistance (HOMA-IR), where a value of >2.0 was considered as IR and that >4.0 was considered as prediabetic state.

RESULTS

Prediabetes was significantly higher among HCV group compared with the control group. Serum fasting glucose, fasting insulin and HOMA-IR levels were significantly higher among prediabetic HCV group compared with both non-prediabetic HCV and control groups.

CONCLUSIONS

HCV patients should be assessed for IR and prediabetes in their routine evaluation to avoid the double burden of diabetes mellitus and HCV.

Coffee and Caffeine Are Associated With Decreased Risk of Advanced Hepatic Fibrosis Among Patients With Hepatitis C

BACKGROUND & AIMS

Coffee or caffeine has been proposed to protect against hepatic fibrosis, but few data are available on their effects in patients with chronic hepatitis C virus (HCV) infection.

METHODS

We conducted a cross-sectional study of veterans with chronic HCV infection to evaluate the association between daily intake of caffeinated and decaffeinated coffee, tea, and soda, and level of hepatic fibrosis, based on the FibroSURE test (BioPredictive, Paris, France) (F0-F3, mild [controls] vs. F3/F4-F4, advanced). Models were adjusted for multiple potential confounders including age, alcohol abuse, and obesity.

RESULTS

Among 910 patients with chronic HCV infection, 98% were male and 38% had advanced hepatic fibrosis. Daily intake of caffeinated coffee was higher among controls than patients with advanced fibrosis (1.37 vs. 1.05 cups/d; P = .038). In contrast, daily intake of caffeinated tea (0.61 vs. 0.56 cups/d; P = .651) or soda (1.14 vs. 0.95 cans/d; P = .106) did not differ between the groups. A higher percentage of controls (66.0%) than patients with advanced fibrosis (57.9%) consumed 100 mg or more of caffeine daily from all sources (P = .014); controls also received a larger proportion of their caffeine from coffee (50.2% vs. 43.0%; P = .035). Hepatoprotective effects of an average daily intake of 100 mg or more of caffeine (adjusted odds ratio, 0.71; 95% confidence interval, 0.53-0.95; P = .020) and 1 cup or more of caffeinated tea by non-coffee drinkers (adjusted odds ratio, 0.56; 95% confidence interval, 0.34-0.94; P = .028) persisted after adjustment for confounders, including insulin resistance.

CONCLUSIONS

A modest daily caffeine intake (as little as 100 mg) may protect against advanced hepatic fibrosis in men with chronic HCV infection. Additional research is needed to confirm these findings in women and in people with other chronic liver diseases.

Insulin resistance as a predictor of early virologic response to HCV therapy among chronic HCV Egyptian patients

Prior assessment of insulin resistance by HOMA-IR is emerging as an important milestone in the treatment of patients with chronic hepatitis C. This cost-effective tool is recommended to individualize treatment duration, or to exclude those with low insulin sensitivity from being treated until ameliorating their state of insulin resistance (IR). The present work aims to elucidate further the effect IR state on early viral kinetic response to Chronic hepatitis C virus (HCV) therapy and the impact of HCV treatment and viral eradication on insulin sensitivity. Insulin sensitivity was assessed using the HOMA-IR method. All enrolled patients were treated with a dual therapy (pegylated interferon-alpha plus ribavirin) for 48 weeks and evaluated using qRT-PCR for early virologic response as well as the impact of treatment on insulin sensitivity throughout the early period of therapy. Of a total 392 chronic HCV cases, early virologic response was achieved by 318 (81.1%). IR was detected in 241 (61.5%) chronic HCV patient of which 73.4% responded to treatment. Early virologic response among patients with > 2.18 HOMA-IR value were significantly lower than those with HOMA-IR values ≤2.18 (P < 0.0001). IR was significantly associated with high baseline BMI. Steatosis and fibrosis correlated with IR but neither independently predicted early virologic response. Pretreatment IR < 2.18, low fasting blood glucose, low and intermediate HCV viral load, normal BMI, and non-smoking were independent factors associated with early virologic response. IR interferes with early virologic response to the antiviral care. Clinical application of pretreatment HOMA-IR assessment could help in predicting early treatment outcome and thus enable treatment regimens to be optimized and individually tailored.

Distinct patterns of the lipid alterations between genotype 1 and 2 chronic hepatitis C patients after viral clearance

BACKGROUND

The hepatitis C virus (HCV) genotype-specific impacts on the host metabolic alterations remained inconclusive.

METHODS

A prospective study including 229 (118 genotype 1 (G1) and 111 G2) consecutive chronic HCV patients who had completed a course of anti-HCV treatment and underwent pre- and 24 weeks post-treatment surveys of metabolic profiles was conducted. Patients were stratified according to the therapeutic response, viral genotype and baseline insulin resistance (IR: homeostasis model assessments of IR (HOMA-IR) ≥ 2.5). Paired t-tests were used to compare the pre- and post-treatment variables.

RESULTS

Significant post-therapeutic increases in cholesterol, triglyceride, HDL, LDL, apolipoprotein A1 and apolipoprotein B were observed in patients with sustained virological response (SVR) but not in those without. Among those with SVR, post-therapeutic increases in HDL (p<0.001) and apolipoprotein A1 (p = 0.012) were only found in G2, whereas increased triglyceride/HDL (p = 0.01) ratios were only found in G1 patients. When stratified by baseline IR among those with SVR, a significant increase in post-treatment HDL (p = 0.019) and apolipoprotein A1 (p = 0.012) but a decrease in HOMA-IR (p = 0.04), C-peptide (p = 0.019) and hemoglobin A1c (p = 0.047) were found in patients with baseline IR; a significant increase in HOMA-IR (p = 0.002) was found in patients without baseline IR. The latter change was observed only in G1 (p = 0.01) but not G2 patients. Although the pre-treatment metabolic profiles of G1 and G2 patients were indifferent, G1 had higher post-treatment triglyceride/HDL ratios (p = 0.041) and triglyceride (p = 0.044) levels than G2 patients.

CONCLUSIONS

G2 benefit more than G1 patients from viral clearance in metabolic alterations, particularly in those without baseline IR.

Association between the hepatitis B and C viruses and metabolic diseases in patients stratified by age

BACKGROUND

Hepatitis B/C viruses cause liver disease and metabolic disturbances.

AIMS

The purpose of this study was to evaluate the association between hepatitis B/C infection and metabolic syndrome (MS).

METHODS

In total, 26,305 subjects were included in this multicentre, cross-sectional study. Systolic and diastolic blood pressures, body mass index and waist circumference were measured. Total cholesterol, high- and low-density lipoprotein cholesterol, triglyceride, fasting blood glucose and uric acid were determined, and hepatitis B serum antigen (HBsAg) and anti-HCV antibodies were assayed using commercial kits.

RESULTS

MS was diagnosed in 2712 (23.0%) females, including 131 and 166 positive for HBsAg and anti-HCV respectively. In the men, 4594 (31.6%) were diagnosed with MS, including 326 positive for HBsAg and 131 positive for anti-HCV. No significant difference in the prevalence of MS was identified in any group, except men and women >45 years who were anti-HCV positive. Various metabolic alterations in both men and women >45 years were noted, including waist circumference, body mass index, fasting blood glucose and systolic and diastolic blood pressure. Notably, high- and low-density lipoproteins were significantly lower in positive subjects compared to those weakly positive and/or negative for anti-HCV.

CONCLUSIONS

There were obvious metabolic derangements in patients coinflicted with MS and hepatitis C infections, particularly those >45 years of age. There is a pressing need to identify strategies to improve/resolve metabolic derangements to maximize sustained virological response rates in patients infected with HCV (and potentially HBV).

CXCL10 antagonism and plasma sDPPIV correlate with increasing liver disease in chronic HCV genotype 4 infected patients

Egypt has the highest prevalence of hepatitis C virus infection worldwide. CXCL10 is a potent chemoattractant that directs effector lymphocytes to sites of inflammation. It has been reported that plasma CXCL10 is processed by dipeptidylpeptidase IV (DPPIV) thus leading to the generation of an antagonist form. Using Luminex-based immunoassays we determined the concentration of different forms of CXCL10 (total, agonist, and antagonist). We also evaluated plasma soluble DPPIV (sDPPIV) concentration and plasma dipeptidylpeptidase (DPP) activity. Using flow cytometry and immunohistochemistry, we analyzed the distribution of lymphocyte subsets. Plasma CXCL10 was elevated in chronic HCV patients, however the agonist form was undetectable. Increased sDPPIV concentration and DPP activity supported the NH2-truncation of CXCL10. Finally, we demonstrated an increased frequency of CXCR3(+) cells in the peripheral blood, and low numbers of CXCR3(+) cells within the lobular regions of the liver. These findings generalize the observation of chemokine antagonism as a mechanism of immune modulation in chronic HCV patients and may help guide the use of new therapeutic immune modulators.

Association of suppressor of cytokine signalling 3 polymorphisms with insulin resistance in patients with chronic hepatitis C

Suppressor of cytokine signalling 3 is thought to be associated with insulin resistance in patients with chronic hepatitis C. We evaluated the role of suppressor of cytokine signalling 3 polymorphisms in determining insulin resistance in patients with chronic hepatitis C. Two hundred and ninety untreated hepatitis C virus-infected patients without diabetes and cirrhosis were genotyped for the SNPs rs4969168, rs4969170 and rs12952093 of suppressor of cytokine signalling 3 using the TaqMan Genotyping Assay. We found that the rs4969170 AA genotype and rs4969170 A allele frequency were significantly more common in the insulin-resistant group than the non-insulin-resistant group (89.5% vs 76.1%, OR = 2.693, 95% CI: 1.221-5.939, P = 0.012 and 94.8% vs 88.0%, OR = 2.463, 95% CI: 1.151-5.271, P = 0.017, respectively). Haplotype G-C was likely associated with non-insulin resistance (adjusted P = 0.011). Multiple logistic regression analysis indicates that the independent risk factors for insulin resistance are the SNP rs4969170 AA genotype (OR = 3.005, 95% CI: 1.194-7.560, P = 0.019), HCV genotype 1 (OR = 2.524, 95% CI: 1.099-5.794, P = 0.029) and BMI (OR = 0.514, 95% CI: 0.265-0.999, P = 0.05).

Hepatitis C virus genotype distribution in Egyptian diabetic patients: a preliminary study

BACKGROUND AND STUDY AIMS

There is controversy regarding whether a specific hepatitis C virus (HCV) genotype is associated with diabetes mellitus. This study aimed to investigate HCV genotype distribution in diabetics and its relation to some clinical and laboratory variables in HCV-positive diabetic versus non-diabetic Egyptians in East Delta.

PATIENTS AND METHODS

The study included 100 HCV-positive patients of which 66 were diabetic in addition to 35 healthy adults as a control group. Clinical assessment, laboratory measurements of plasma glucose, insulin, C-peptide, C-reactive protein (CRP), tumour necrosis factor-α (TNF-α) and liver functions (alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyltransferase (GGT)) as well as HCV genotype determination were done, and AST/platelet ratio index (APRI) and Homoeostasis Model of Assessment-Insulin Resistance (HOMA-IR) were calculated.

RESULTS

The main results were the presence of HCV genotype 3, in 31.8% of the diabetic group and in 26.5% of the non-diabetic group, while the remainder of cases had genotype 4, the predominant genotype in Egypt. This is the first report of the presence of HCV genotype 3 in about 30% of an Egyptian cohort. However, there was no significant difference in genotype distribution between both groups. Further, there were significantly higher values of HOMA-IR, insulin and C-peptide in HCV-positive groups in comparison to the control group, while TNF-α was significantly higher in the HCV-positive diabetic group. However, there were no significant differences between both genotypes regarding these parameters.

CONCLUSION

Although this study reveals for the first time the presence of HCV genotype 3 in a significant percentage of a group of Egyptian patients, where the majority were diabetic, the association between diabetes and certain HCV genotypes could not be confirmed on the basis of our findings. Hence, taking into consideration the impact of such a finding on the treatment decisions of those patients, further studies are warranted to explore these findings to a greater extent.

Absence of liver steatosis in HIV-HCV co-infected patients receiving regimens containing tenofovir or abacavir

BACKGROUND

In human immunodeficiency virus-hepatitis C virus (HIV-HCV) co-infected patients, steatosis has been independently associated with a number of antiretroviral drugs, including stavudine, especially in patients with non-3 HCV genotypes. We retrospectively investigated the presence of steatosis among HIV-HCV co-infected and HCV mono-infected patients, and the role of tenofovir disoproxil fumarate (TDF) or abacavir (ABC) in determining hepatic steatosis.

METHODS

Liver steatosis was retrospectively evaluated in all consecutive biopsies performed in the period 2000-2008 in HCV mono-infected and HIV-HCV co-infected patients. A steatosis rate of >5 % was considered to be significant, and a multivariate logistic analysis was performed to evaluate factors associated with steatosis.

RESULTS

In total, 393 HCV-infected patients underwent liver biopsy during the study period, of whom 205 (52.2 %) were co-infected with HIV. A steatosis rate of >5 % was diagnosed in 33.0 % of HCV mono-infected and in 47.8 % of HIV-HCV co-infected patients (P = 0.003). The rate of steatosis was higher in patients resuming antiretroviral therapy (54.7 %) than in naïve patients (33.3 %; P = 0.006). When the overall population was considered, steatosis was associated to HCV genotype 3 [odds ratio (OR) 4.53, 95 % confidence interval (CI) 2.71-7.58; P < 0.001]. In terms of the use of nucleos(t)ide drugs in HIV co-infected patients, multivariate analysis showed that only in patients with HCV genotypes other than genotype 3 was steatosis related to the use of stavudine (OR 5.38, 95 % CI 1.18-24.53; P = 0.03). The use of TDF (OR 1.07, 95 % CI 0.39-2.88; P = 0.898) or ABC (OR 0.592, 95 % CI 0.09-4.07; P = 0.594) was not associated with steatosis.

CONCLUSION

In HCV mono-infected and HIV-HCV co-infected patients, steatosis appears to be a virus-mediated effect of HCV genotype 3. In HIV patients infected with HCV genotypes other than genotype 3, the risk of developing steatosis was higher in those patients resuming antiretroviral regimens containing old drugs rather than the new antiretrovirals.

Relationship between hepatitis C virus infection and type 2 diabetes mellitus: meta-analysis

AIM

To investigate the association between hepatitis C infection and type 2 diabetes mellitus.

METHODS

Observational studies assessing the relationship between hepatitis C infection and type 2 diabetes mellitus were identified via electronic and hand searches. Studies published between 1988 to March 2011 were screened, according to the inclusion criteria set for the present analysis. Authors performed separate analyses for the comparisons between hepatitis C virus (HCV) infected and not infected, and HCV infected and hepatitis B virus infected. The included studies were further subgrouped according to the study design. Heterogenity was assessed using I(2) statistics. The summary odds ratios with their corresponding 95% CIs were calculated based on a random-effects model. The included studies were subgrouped according to the study design. To assess any factor that could potentially affect the outcome, results were further stratified by age group (proportion of ≥ 40 years), gender (proportion of male gender), body mass index (BMI) (proportion of BMI ≥ 27), and family history of diabetes (i.e., self reported). For stability of results, a sensitivity analysis was conducted including only prospective studies.

RESULTS

Combining the electronic database and hand searches, a total of 35 observational studies (in 31 articles) were identified for the final analysis. Based on random-effects model, 17 studies (n = 286,084) compared hepatitis C-infected patients with those who were uninfected [summary odds ratio (OR): 1.68, 95% CI: 1.15-2.45]. Of these 17 studies, 7 were both a cross-sectional design (41.2%) and cohort design (41.2%), while 3 were case-control studies (17.6%). Nineteen studies (n = 51,156) compared hepatitis C-infected participants with hepatitis B-infected (summary OR: 1.92, 95% CI: 1.41-2.62). Of these 19 studies, 4 (21.1%), 6 (31.6%) and 9 (47.4%) were cross-sectional, cohort and case-control studies, respectively. A sensitivity analysis with 3 prospective studies indicated that hepatitis C-infected patients had a higher risk of developing type 2 diabetes compared with uninfected controls (summary odds ratio: 1.41, 95% CI: 1.17-1.7; I(2) = 0%). Among hepatitis C-infected patients, male patients (OR: 1.26, 95% CI: 1.03-1.54) with age over 40 years (summary OR: 7.39, 95% CI: 3.82-9.38) had an increased frequency of type 2 diabetes. Some caution must be taken in the interpretation of these results because there may be unmeasured confounding factors which may introduce bias.

CONCLUSION

The findings support the association between hepatitis C infection and type 2 diabetes mellitus. The direction of association remains to be determined, however. Prospective studies with adequate sample sizes are recommended.

Association of caffeine intake and histological features of chronic hepatitis C

BACKGROUND & AIMS

The severity of chronic hepatitis C (CHC) is modulated by host and environmental factors. Several reports suggest that caffeine intake exerts hepatoprotective effects in patients with chronic liver disease. The aim of this study was to evaluate the impact of caffeine consumption on activity grade and fibrosis stage in patients with CHC.

METHODS

A total of 238 treatment-naïve patients with histologically-proven CHC were included in the study. Demographic, epidemiological, environmental, virological, and metabolic data were collected, including daily consumption of alcohol, cannabis, tobacco, and caffeine during the six months preceding liver biopsy. Daily caffeine consumption was estimated as the sum of mean intakes of caffeinated coffee, tea, and caffeine-containing sodas. Histological activity grade and fibrosis stage were scored according to Metavir. Patients (154 men, 84 women, mean age: 45±11 years) were categorized according to caffeine consumption quartiles: group 1 (<225 mg/day, n=59), group 2 (225-407 mg/day, n=57), group 3 (408-678 mg/day, n=62), and group 4 (>678 mg/day, n=60).

RESULTS

There was a significant inverse relationship between activity grade and daily caffeine consumption: activity grade>A2 was present in 78%, 61%, 52%, and 48% of patients in group 1, 2, 3, and 4, respectively (p<0.001). By multivariate analysis, daily caffeine consumption greater than 408 mg/day was associated with a lesser risk of activity grade>A2 (OR=0.32 (0.12-0.85). Caffeine intake showed no relation with fibrosis stage.

CONCLUSIONS

Caffeine consumption greater than 408 mg/day (3 cups or more) is associated with reduced histological activity in patients with CHC. These findings support potential hepatoprotective properties of caffeine in chronic liver diseases.

Evidence for an antagonist form of the chemokine CXCL10 in patients chronically infected with HCV

Chronic infection with hepatitis C virus (HCV) is a major public health problem, with nearly 170 million infected individuals worldwide. Current treatment for chronic infection is a combination of pegylated IFN-α2 and ribavirin (RBV); however, this treatment is effective in fewer than 50% of patients infected with HCV genotype 1 or 4. Recent studies identified the chemokine CXCL10 (also known as IP-10) as an important negative prognostic biomarker. Given that CXCL10 mediates chemoattraction of activated lymphocytes, it is counterintuitive that this chemokine correlates with therapeutic nonresponsiveness. Herein, we offer new insight into this paradox and provide evidence that CXCL10 in the plasma of patients chronically infected with HCV exists in an antagonist form, due to in situ amino-terminal truncation of the protein. We further demonstrated that dipeptidyl peptidase IV (DPP4; also known as CD26), possibly in combination with other proteases, mediates the generation of the antagonist form(s) of CXCL10. These data offer what we believe to be the first evidence for CXCL10 antagonism in human disease and identify a possible factor contributing to the inability of patients to clear HCV.

Chronic hepatitis C is associated with peripheral rather than hepatic insulin resistance

BACKGROUND & AIMS

Chronic hepatitis C (CHC) is associated with insulin resistance (IR), liver steatosis (genotype 3), and increased diabetes risk. The site and mechanisms of IR are unclear.

METHODS

We compared cross-sectionally 29 nonobese, normoglycemic males with CHC (genotypes 1 and 3) to 15 adiposity and age-matched controls using a 2-step hyperinsulinemic-euglycemic clamp with [6,6-(2)H(2)] glucose to assess insulin sensitivity in liver and peripheral tissues and (1)H-magnetic resonance spectroscopy to evaluate liver and intramyocellular lipid. Insulin secretion was assessed after intravenous glucose.

RESULTS

Insulin secretion was not impaired in CHC. Peripheral insulin sensitivity was 35% higher in controls vs CHC (P < .001) during high-dose (264.3 +/- 25 [standard error] mU/L) insulin (P < .001); this was negatively associated with viral load (R(2) = .12; P = .05) and subcutaneous fat (R(2) = .41; P < .001). IR was similar in both genotypes despite 3-fold increased hepatic fat in genotype 3 (P < .001). Hepatic glucose production (P = .25) and nonesterified free fatty acid (P = .84) suppression with insulin were not different between CHC and controls inferring no adipocyte IR, and suggesting IR is mainly in muscle. In CHC, intramyocellular lipid was nonsignificantly increased but levels of glucagon (73.8 +/- 3.6 vs 52.8 +/- 3.1 ng/mL; P < .001), soluble tumor necrosis factor receptor 2 (3.1 +/- 0.1 vs 2.3 +/- 0.1 ng/mL; P < .001), and Lipocalin-2 (36.4 +/- 2.9 vs 19.6 +/- 1.6 ng/mL; P < .001) were elevated.

CONCLUSIONS

CHC represents a unique infective/inflammatory model of IR, which is predominantly in muscle, correlates with subcutaneous, not visceral, adiposity, and is independent of liver fat.

The value of transabdominal ultrasound for assessment of the severity of liver steatosis as compared to liver biopsy

The purpose of our paper was to evaluate the performance of ultrasound (US) for assessment of the severity of liver steatosis as compared to a pathological examination, which is presently considered to be the gold standard, in patients that have undergone liver biopsy for various reasons. We performed echo-assisted liver biopsy in 161 patients with chronic hepatitis with the US aspect of “bright liver” with “posterior attenuation”, using modified Menghini needles. Following the US examination, the severity of liver steatosis was estimated as minimal, mild, moderate. or severe according to the Hepburn classification: absent (affecting 0% to 2% of the hepatocytes), minimal (2% to 10%), mild (10% to 30%), moderate (30% to 60%), and severe (more than 60% of the hepatocytes). The results of this study showed that the sensitivity of US for the prediction of histological steatosis of at least moderate severity was 0.64, with 0.77 specificity, 0.55 positive predictive value, and 0.94 negative predictive value. The overall accuracy was 0.75. This study showed that the transabdominal ultrasound evaluation of the fatty liver is a quite good predictor, perhaps sufficient for most purposes, for the estimation of the severity of liver steatosis in the moderate to severe range.

Serum HCV RNA levels and HCV genotype do not affect insulin resistance in nondiabetic patients with chronic hepatitis C: a multicentre study

BACKGROUND

Chronic hepatitis C (CHC) induces insulin resistance (IR) and subsequently diabetes.

AIM

To examine viral, metabolic and histological predictors of IR in 275 CHC patients to test the hypothesis that IR differs among HCV genotypes and that viral replication directly affects IR.

METHODS

We studied 275 nondiabetic treatment-naïve CHC patients. Histological lesions were evaluated according to Ishak. IR was assessed using homeostasis model assessment for insulin resistance (HOMA-IR).

RESULTS

HOMA > 3.0 was found in 37% of patients, independently associated with higher BMI and GGT. In genotype non-3 patients, HOMA > 3.0 was associated with higher BMI and GGT values, while no significant association was noted in genotype 3 patients. In non-obese patients with minimal fibrosis, HOMA > 3.0 was found in 20% of cases without significant differences among genotypes. No association between HOMA > 3.0 and HCV-RNA levels was found. Severe fibrosis (stage 5-6) related to older age (OR:1.048), HOMA-IR (OR:1.177), necroinflammation (OR: 2.990) and higher ALT (OR: 1.009) and GGT (OR:1.006).

CONCLUSIONS

IR develops at early stages of CHC without significant differences among genotypes. It is more frequent in obese patients with steatosis and contributes to fibrosis progression. However, IR does not seem to be associated with viraemia and therefore its exact pathogenetic mechanism in CHC remains elusive.

Adiponectin changes in HCV-Genotype 4: relation to liver histology and response to treatment

Recently, attention has been focussed on adiponectin and its changes in different types of chronic liver disease. Its relation to hepatic fibrosis and insulin resistance in post-hepatitis liver disease is not clear. The aim of this study was to clarify the adiponectin changes in genotype 4 hepatitis C virus (HCV)-infected patient in relation to liver histology and insulin resistance, and its usefulness as a predictor of hepatic fibrosis and response to treatment. Total adiponectin and its high molecular weight (HMW) form as well as insulin levels were studied in 92 chronic HCV, genotype 4 and 66 healthy control volunteers. Neither total adiponectin (r = 0.101, P = 0.220) nor HMW adiponectin (r = 0.081, P = 0.328) correlated with viral load. Total and not HMW adiponectin was significantly correlated with hepatic fibrosis and inflammation (r = 0.267, P = 0.002, r = 0.278, P < 0.001, respectively).In addition, total adiponectin (r = 0.224, P = 0.002) and HMW adiponectin (r = 0.266, P < 0.0006) significantly correlated with insulin resistance. As fibrosis did not correlate with insulin resistance (r = 0.081, P = 0.204), the correlation between total adiponectin and fibrosis was not mediated by insulin resistance. Multivariable regression analysis, (including pretreatment cases and controls) revealed that total adiponectin was significantly associated with gender, being lower among male subjects (X(2) = 13.04, P = 0.0001). The multivariable regression model supported the lack of association between insulin resistance and total adiponectin levels (X(2) = 1.88, P = 0.171), while non cirrhotics had significantly lower total adiponectin levels than cirrhotics (X(2) = 10.90, P = 0.004) and lower level of inflammation significantly lower total adiponectin levels than more severe inflammation (X(2) = 8.95, P = 0.003). Total or HMW adiponectin did not yield receiver operating characteristic (ROC) curves with area under the curve (AUC) >75%, thus the cutoff points have poor sensitivity/specificity as predictors of fibrosis. However, as a predictor of end-of-treatment response, the ROC curve of adiponectin index gave yield an AUC = 81.4%. We can conclude that total adiponectin level, in HCV genotype 4 patients, increases with progression of hepatic fibrosis regardless of insulin resistance. Its high molecular form does not have such correlation. The adiponectin changes are not related to viral load, insulin resistance or other demographic data suggesting that this change is histologically related. In spite of this, no adiponectin cutoff level had reasonable sensitivity/specificity for predicting hepatic fibrosis stage, while this may be used as a predictor for antiviral response possibly reflecting improvement in hepatic inflammation post treatment.

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.

Influence of insulin resistance on hepatic fibrosis and steatosis in hepatitis C virus (HCV) mono-infected compared with HIV-HCV co-infected patients

BACKGROUND

Insulin resistance (IR), the major feature of the metabolic syndrome, is also common in patients with chronic HCV infection. Liver fibrosis and steatosis are known potential outcome of chronic hepatitis B or C infection. Studies have shown that HIV positive individuals co-infected with HCV have more rapid live disease progression than those with HIV alone. Few data have reported the influence of IR on steatosis and fibrosis in the context of HIV-HCV coinfection.

AIM

To test the association among insulin resistance (IR), liver fibrosis and liver steatosis in HIV-HCV and HCV-infected patients.

PATIENTS AND METHODS

A total of 170 HIV-HCV-infected patients matched by age, gender and genotype with 170 HCV mono-infected patients were included. Patients were considered to be IR when the homeostasis model assessment of IR >2. Significant fibrosis was considered if METAVIR >or=F2 and significant steatosis if >or=10%.

RESULTS

Insulin resistance was independently associated in HCV patients with fibrosis [odds ratio (OR) = 2.04 (95% CI 1.02-4)], a body mass index (BMI) >25 kg/m(2) [OR = 3.33 (1.47-7.69)] and steatosis [OR = 3.33 (1.67-6.67)]. Fibrosis >or=F2 was associated in HCV patients with high liver activity grade (>or=A2) [OR = 8.33 (3.85-16.67)], male gender [OR = 3.03 (1.33-7.14)] and IR [OR = 2.44 (1.15-5)]. In HIV-HCV patients, >or=A2 [OR = 5.56 (1.64-20)] was associated with fibrosis. Steatosis >or=10% was associated in HCV patients with IR [OR = 3.13 (1.59-6.25) and >or=F2 (OR = 2.22 (1.15-4.17)]. In HIV-HCV, a BMI >25 kg/m(2) [OR = 3.85 (1.64-9.10)], >or=A2 [OR = 2.16 (1.02-4.55); P = 0.044] and nucleoside reverse transcriptase inhibitor [OR = 3.61 (1.19-10.96); P = 0.023] were independently associated with significant liver steatosis.

CONCLUSIONS

Insulin resistance is associated with liver fibrosis and steatosis in HCV mono-infected, but not in HIV-HCV co-infected patients. Significant liver fibrosis is associated with IR independent of liver steatosis only in HCV mono-infected patients.

Hepatitis C virus and type 2 diabetes

This review focuses on the relationship between hepatitis C virus (HCV) infection and glucose metabolism derangements. Cross-sectional and longitudinal studies have shown that the chronic HCV infection is associated with an increased risk of developing insulin resistance (IR) and type 2 diabetes (T2D). The direct effect of HCV on the insulin signaling has been analyzed in experimental models. Although currently available data should be considered as preliminary, HCV seems to affect glucose metabolism via mechanisms that involve cellular pathways that have been implicated in the host innate immune response. IR and T2D not only accelerate the histological and clinical progression of chronic hepatitis C, but also reduce the early and sustained virological response to interferon-alpha-based therapy. Thus, a detailed knowledge of the mechanisms underlying the HCV-associated glucose metabolism derangements is warranted, in order to improve the clinical management of chronic hepatitis C patients.

Insulin resistance and metabolic syndrome in chronic liver diseases: old entities with new implications

Insulin resistance (IR) and metabolic syndrome have recently been implicated in the pathogenesis and progression of chronic liver diseases, especially chronic hepatitis C (CHC) and non-alcoholic fatty liver disease (NAFLD). In this review, we provide current information on their deleterious effect on the liver, with particular interest in those two entities. In NAFLD, IR causes both the accumulation of fat in hepatocytes and the progression to non-alcoholic steatohepatitis (NASH). Moreover, the presence of metabolic syndrome seems to be associated with severe fibrosis in NASH patients. In CHC, IR develops early in the course of the disease and precedes steatosis. It is also independently associated with histological severity and negatively affects treatment response, irrespective of genotype. Consequently, therapies targeting IR and metabolic syndrome could indirectly ameliorate the prognosis of both NAFLD and CHC. As specific therapies do not exist, patients with metabolic syndrome and CHC and NAFLD should be counseled to lose weight and ameliorate their glycemic control and lipid profile.

Steatosis, liver injury, and hepatocarcinogenesis in hepatitis C viral infection

In addition to the link with development of hepatocellular carcinoma (HCC), hepatitis C virus (HCV) infection is associated with several hepatic and extrahepatic manifestations. A role of hepatic steatosis in the pathogenesis of chronic hepatitis C has been shown, implying hepatitis C as a metabolic disease. Furthermore, recent epidemiological studies have suggested a linkage between insulin resistance and chronic HCV infection. In addition to the data indicating the presence of lipid metabolism disturbance and insulin resistance in the cohort of chronic hepatitis C patients, we found evidence showing the association between these two conditions and HCV infection using mice transgenic for the HCV core gene. These mice develop HCC late in life after the phase of hepatic steatosis and insulin resistance. The nonappearance of both steatosis and HCC in HCV core gene transgenic mice that are null for the proteasome activator 28gamma implies a close relationship between lipid metabolism disturbance and hepatocarcinogenesis. Also, the core protein is shown to bind with retinoid X receptor (RXR)-alpha, resulting in the upregulation of some lipid metabolism enzymes, including cellular retinol binding protein II and acyl-CoA oxidase. In addition, the persistent activation of peroxisome proliferator activated receptor (PPAR)-alpha has recently been found in the liver of HCV core gene transgenic mice, yielding dramatic changes in lipid metabolism and hepatocyte proliferation, including HCC development. These results would provide a clue for further understanding of the role of lipid metabolism in pathogenesis of HCV infection, including liver injury and hepatocarcinogenesis.

Hepatitis C virus infection protein network

A proteome-wide mapping of interactions between hepatitis C virus (HCV) and human proteins was performed to provide a comprehensive view of the cellular infection. A total of 314 protein-protein interactions between HCV and human proteins was identified by yeast two-hybrid and 170 by literature mining. Integration of this data set into a reconstructed human interactome showed that cellular proteins interacting with HCV are enriched in highly central and interconnected proteins. A global analysis on the basis of functional annotation highlighted the enrichment of cellular pathways targeted by HCV. A network of proteins associated with frequent clinical disorders of chronically infected patients was constructed by connecting the insulin, Jak/STAT and TGFbeta pathways with cellular proteins targeted by HCV. CORE protein appeared as a major perturbator of this network. Focal adhesion was identified as a new function affected by HCV, mainly by NS3 and NS5A proteins.

HIV Coinfection and Antiretroviral Therapy Enhances Liver Steatosis in Patients with Hepatitis C, but Only in those Infected by HCV Genotype other than 3

Background

Liver steatosis is a common finding in hepatitis C virus (HCV) infection and is associated with an increased progression of the disease. However, HCV genotype 3 steatosis presents a peculiar and virus-induced pathogenesis. We analysed the effect of HIV coinfection and antiretroviral therapy on hepatic steatosis and the effect of the steatosis on fibrosis in patients with or without HCV genotype 3 infection.

Methods

All consecutive HIV-infected and uninfected patients who had undergone a liver biopsy for evaluation of HCV infection at the Infectious Diseases Clinic (Modena, Italy) were included in this study. Primary outcomes were the presence or absence of steatosis or the presence of moderate or advanced fibrosis.

Results

A total of 284 patients were enrolled: 187 infected by HCV and 97 coinfected with HIV and HCV. In HCV genotype 3 patients, only HCV-related variables, such as plasma HCV RNA levels (odds ratio [OR] per log10 1.68, P<0.001) and estimated duration of HCV infection (OR per year 1.17, P=0.004) were associated with steatosis. In patients infected with other HCV genotypes, steatosis was associated with older age (OR per 5 years 1.47, P<0.001), with exposure to d-drugs in HIV–HCV-coinfected patients (OR 2.60, P=0.04) and specifically exposure to stavudine (OR 2.76 HIV–HCV-coinfected versus not HIV-infected patients, P=0.04). Steatosis was independently associated with bridging fibrosis only in patients infected by HCV genotype other than 3 (OR 4.03, P=0.01).

Conclusions

Hepatic steatosis, in both HCV-monoinfected and in HIV–HCV-coinfected patients, is strongly correlated with HCV genotype 3, probably through interactions between HCV virus and liver cells. HIV-related increase of steatosis in patients with HCV is probably related to anti-retroviral drugs, especially stavudine, in patients infected by HCV genotype other than 3.

Virus-induced over-expression of protein phosphatase 2A inhibits insulin signalling in chronic hepatitis C

BACKGROUND/AIMS

Hepatitis C virus (HCV) infection disturbs glucose and lipid metabolism contributing to the development of liver steatosis, insulin resistance and type 2 diabetes mellitus. On the other hand, insulin resistance and steatosis have been found to be associated with increased rates of fibrosis progression and lower rates of response to interferon therapy in chronic hepatitis C (CHC). The molecular mechanisms contributing to insulin resistance in CHC are not well understood. We have shown previously that protein phosphatase 2A (PP2A) is over-expressed in biopsies from patients with CHC. In this study, we tested if PP2A over-expression leads to insulin resistance.

METHODS

We studied insulin signalling in cell lines that allow the regulated over-expression of HCV proteins and of the PP2A catalytic subunit (PP2Ac). Insulin signalling and PP2Ac expression were also studied in HCV transgenic mice and in liver biopsies from patients with CHC.

RESULTS

Over-expression of PP2Ac in cells inhibited insulin signalling by dephosphorylation of PKB/Akt. PP2Ac over-expression and impaired insulin signalling were found in the liver of HCV transgenic mice and in liver biopsies of patients with CHC.

CONCLUSIONS

HCV-induced over-expression of PP2A in the liver contributes to the pathogenesis of insulin resistance in patients with CHC.

Hepatitis C virus core protein induces lipid droplet redistribution in a microtubule- and dynein-dependent manner

Attachment of hepatitis C virus (HCV) core protein to lipid droplets (LDs) is linked to release of infectious progeny from infected cells. Core progressively coats the entire LD surface from a unique site on the organelle, and this process coincides with LD aggregation around the nucleus. We demonstrate that LD redistribution requires only core protein and is accompanied by reduced abundance of adipocyte differentiation-related protein (ADRP) on LD surfaces. Using small hairpin RNA technology, we show that knock down of ADRP has a similar phenotypic effect on LD redistribution. Hence, ADRP is crucial to maintain a disperse intracellular distribution of LDs. From additional experimental evidence, LDs are associated with microtubules and aggregate principally around the microtubule-organizing centre in HCV-infected cells. Disrupting the microtubule network or microinjecting anti-dynein antibody prevented core-mediated LD redistribution. Moreover, microtubule disruption reduced virus titres, implicating transport networks in virus assembly and release. We propose that the presence of core on LDs favours their movement towards the nucleus, possibly to increase the probability of interaction between sites of HCV RNA replication and virion assembly.

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

BACKGROUND/AIMS

Insulin resistance reduces the response to interferon alfa-based therapy of chronic hepatitis C patients. It has been speculated that improvement of insulin sensitivity might increase the chances of responding to treatment of such individuals.

METHODS

We started a multicenter clinical trial of retreatment of chronic hepatitis C patients, who had failed to respond to the pegylated interferon alfa/ribavirin combination, with a triple therapy consisting in these same antivirals plus an insulin-sensitizer (pioglitazone) (The INSPIRED-HCV study).

RESULTS

None of the first five patients fulfilling the inclusion criteria and included in the trial achieved a satisfactory virological response after 12 weeks of retreatment, despite the fact that in at least three of them the insulin resistance score improved. As a result, the study was terminated.

CONCLUSIONS

Different schedules are warranted to improve insulin sensitivity prior to attempting retreatment of chronic hepatitis C patients with insulin resistance.

Environmental factors as disease accelerators during chronic hepatitis C

Progression of chronic hepatitis is highly variable among individuals, as the result of several host, viral and environmental factors. The latter have been extensively investigated in order to ameliorate hepatitis C outcome, particularly in difficult-to-treat patients. Over the last decade, several studies have shown that a combination of HCV infection and high levels of alcohol abuse results in synergistic acceleration of liver fibrogenesis. In addition, recent data indicate that light alcohol intake may also exacerbate fibrosis progression. It has also been suggested that cigarette smoking may enhance activity grade in patients with chronic hepatitis C, thereby increasing progression of fibrosis. This assumption mostly relies on epidemiological evidences in the absence of pathogenic studies. Finally, cannabis use is increasingly emerging as a novel co-morbidity in patients with chronic hepatitis C. Indeed, regular cannabis smoking is an independent predictor of both fibrosis and steatosis severity in infected patients. In addition, experimental studies have shown that cannabinoid CB1 receptors enhance liver fibrogenesis and steatogenesis by distinct mechanisms, therefore strongly supporting epidemiological findings. Altogether, patients should be informed of the deleterious impact of alcohol, tobacco and cannabis use and should be offered appropriate support to achieve abstinence.

Insulin resistance in chronic hepatitis C: association with genotypes 1 and 4, serum HCV RNA level, and liver fibrosis

BACKGROUND & AIMS

Our study was designed to test the association between insulin resistance (IR) and hepatitis C virus (HCV) genotypes, serum HCV RNA level and liver fibrosis stage in a large prospective cohort of chronic hepatitis C (CHC) patients.

METHODS

Six hundred consecutive patients (CHC, n = 500; chronic hepatitis B (CHB), n = 100) were evaluated on the day of liver biopsy. IR (Homeostasis Model for Assessment of Insulin Resistance) and all components of the metabolic syndrome were assessed. By logistic regression, independent factors associated with IR and those associated with significant fibrosis were assessed in nondiabetic and noncirrhotic CHC, respectively. Parameters of IR were compared between hepatitis B and 240 CHC matched by epidemiologic, metabolic, and histologic features.

RESULTS

IR was present in 32.4% of the 462 nondiabetic CHC and associated with the metabolic syndrome, genotypes 1 and 4, significant fibrosis, and severe steatosis. IR was diagnosed in 15% of 145 CHC without metabolic syndrome or significant fibrosis, and associated with genotypes 1 and 4, high serum HCV RNA level, and moderate-severe necroinflammation. Significant fibrosis was present in 51.1% of the 454 noncirrhotic CHC patients and associated with male sex, age >40 years, IR, moderate-severe necroinflammation, and severe steatosis. IR was less frequent in CHB than in matched CHC (5% vs 35%, respectively, P < .001).

CONCLUSIONS

IR is a specific feature of CHC, associated with genotypes 1 and 4 and high serum HCV RNA level. Significant fibrosis is associated with IR independent from steatosis.

Identification of liver fibrosis in HIV/HCV-coinfected patients using a simple predictive model based on routine laboratory data

We constructed noninvasive models to predict significant fibrosis (F > or = 2) and advanced fibrosis (F > or = 3) among human immunodeficiency virus (HIV)/hepatitis C virus (HCV)-coinfected patients, naïve for anti-HCV treatment. A total of 296 patients with liver biopsy were randomly assigned to an estimation group (EG = 226; 70%) and a validation group (VG = 70; 30%). We developed the Hospital Gregorio Marañón (HGM)-1 index, based on platelet count, aspartate aminotransferase (AST) and glucose, to predict F > or = 2 and the HGM-2 index, based on platelet count, international normalized ratio, alkaline phosphatase and AST to predict F > or = 3. The area under the receiver operating characteristic curves (AUROCs) of the HGM-1 index for the EG and the VG were 0.807 and 0.712 respectively. The AUROCs of the HGM-2 index for the EG and the VG were 0.844 and 0.815 respectively. With the HGM-1 index applied to the VG, using best cutoff scores, the negative predictive value (NPV) to exclude F > or = 2 was 54.5% and the positive predictive value (PPV) to confirm F > or = 2 was 93.3%. With the HGM-2 index applied to the VG, using best cutoff scores, the NPV to exclude F > or = 3 was 92.3, and the PPV to confirm F > or = 3 was 64.3%. Thus, HGM-2 accurately predicted F > or = 3 among HIV/HCV-coinfected patients. HGM-1 was less accurate at predicting F > or = 2.

Hepatic steatosis in chronic hepatitis B develops due to host metabolic factors: a comparative approach with genotype 1 chronic hepatitis C

BACKGROUND/AIMS

Hepatic steatosis has not been adequately studied in chronic hepatitis B, while it is considered to be a cardinal feature in chronic hepatitis C and to be mainly metabolically induced in patients infected with genotype 1. We investigated the prevalence of and the parameters associated with steatosis in HBeAg-negative chronic hepatitis B.

METHODS

We studied 213 patients with HBeAg-negative chronic hepatitis B and compared them with 163 patients with genotype-1 chronic hepatitis C. Steatosis was semi-quantitatively graded.

RESULTS

Steatosis was significantly less frequent in chronic hepatitis B than chronic hepatitis C (60% versus 72%, P=0.016), but there was no difference in the prevalence of moderate/severe steatosis. In chronic hepatitis B, steatosis was associated only with higher body mass index (P=0.002), while moderate/severe steatosis was associated only with higher body mass index (P=0.043) and diabetes (P=0.031). Steatosis was relatively less frequent in chronic hepatitis B than chronic hepatitis C non-diabetic, normal-weight patients (45.6% versus 62.5%, P=0.063), but it did not differ in diabetic and/or overweight/obese patients with chronic hepatitis B or chronic hepatitis C.

CONCLUSIONS

Hepatic steatosis in HBeAg-negative chronic hepatitis B (a) is less frequent than in genotype-1 chronic hepatitis C, (b) is mainly associated with presence of host metabolic factors, such as high body mass index and diabetes and (c) does not seem to be associated with the severity of liver histological lesions.