Insulin resistance and steatosis in HBV-HCV co-infected patients: Role of PNPLA3 polymorphisms and impact on liver fibrosis progression

HBV Infection and Host Interactions: The Role in Viral Persistence and Oncogenesis

Hepatitis B virus (HBV) is a major cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. Despite the advent of vaccines and potent antiviral agents able to suppress viral replication, recovery from chronic HBV infection is still an extremely difficult goal to achieve. Complex interactions between virus and host are responsible for HBV persistence and the risk of oncogenesis. Through multiple pathways, HBV is able to silence both innate and adaptive immunological responses and become out of control. Furthermore, the integration of the viral genome into that of the host and the production of covalently closed circular DNA (cccDNA) represent reservoirs of viral persistence and account for the difficult eradication of the infection. An adequate knowledge of the virus-host interaction mechanisms responsible for viral persistence and the risk of hepatocarcinogenesis is necessary for the development of functional cures for chronic HBV infection. The purpose of this review is, therefore, to analyze how interactions between HBV and host concur in the mechanisms of infection, persistence, and oncogenesis and what are the implications and the therapeutic perspectives that follow.

Molecular mechanisms underlying hepatitis C virus infection-related diabetes

Diabetes is a noncommunicable widespread disease that poses the risk of severe complications in patients, with certain complications being life-threatening. Hepatitis C is an infectious disease that mainly causes liver damage, which is also a profound threat to human health. Hepatitis C virus (HCV) infection has many extrahepatic manifestations, including diabetes. Multiple mechanisms facilitate the strong association between HCV and diabetes. HCV infection can affect the insulin signaling pathway in liver and pancreatic tissue and change the profiles of circulating microRNAs, which may further influence the occurrence and development of diabetes. This review describes how HCV infection causes diabetes and discusses the current research progress with respect to HCV infection-related diabetes.

Non-Alcoholic Fatty Liver Disease: From Pathogenesis to Clinical Impact

Non-Alcoholic Fatty Liver Disease (NAFLD) is caused by the accumulation of fat in over 5% of hepatocytes in the absence of alcohol consumption. NAFLD is considered the hepatic manifestation of metabolic syndrome (MS). Recently, an expert consensus suggested as more appropriate the term MAFLD (metabolic-associated fatty liver disease). Insulin resistance (IR) plays a key role in the development of NAFLD, as it causes an increase in hepatic lipogenesis and an inhibition of adipose tissue lipolysis. Beyond the imbalance of adipokine levels, the increase in the mass of visceral adipose tissue also determines an increase in free fatty acid (FFA) levels. In turn, an excess of FFA is able to determine IR through the inhibition of the post-receptor insulin signal. Adipocytes secrete chemokines, which are able to enroll macrophages inside the adipose tissue, responsible, in turn, for the increased levels of TNF-α. The latter, as well as resistin and other pro-inflammatory cytokines such as IL-6, enhances insulin resistance and correlates with endothelial dysfunction and an increased cardiovascular (CV) risk. In this review, the role of diet, intestinal microbiota, genetic and epigenetic factors, low-degree chronic systemic inflammation, mitochondrial dysfunction, and endoplasmic reticulum stress on NAFLD have been addressed. Finally, the clinical impact of NAFLD on cardiovascular and renal outcomes, and its direct link with type 2 diabetes have been discussed.

Reduced incidence of type 2 diabetes in patients with chronic hepatitis C virus infection cleared by direct-acting antiviral therapy: A prospective study

AIM

To assess the effect of hepatitis C virus (HCV) eradication on type 2 diabetes mellitus (T2DM). incidence.

METHODS

A prospective multicentre case-control study was performed, which included 2426 patients with HCV, 42% of whom had liver fibrosis stage F0-F2 and 58% of whom had liver fibrosis stage F3-F4. The study population consisted of a control group including 1099 untreated patients and 1327 cases treated with direct-acting antivirals (DAAs). T2DM incidence was assessed during a median (interquartile range) follow-up period of 30 (28-42) months. Risk factors for T2DM were assessed using a Cox regression model (relative risk [RR], hazard ratio [HR], Kaplan-Meier analysis). Insulin sensitivity was evaluated by homeostatic model assessment (HOMA) and changes by repeated-measures ANOVA. Factors independently associated with T2DM were assessed by multivariate analysis.

RESULTS

The absolute incidence of T2DM for controls and cases was 28 and 7/1000 person-years, respectively (P = 0.001). In cases compared to controls, HCV clearance reduced the RR and HR of T2DM by 81% and 75% to 93%, respectively (P = 0.001). It was calculated that, for every 15 patients who obtained HCV clearance, one case of T2DM was saved. HCV clearance was associated with significant reductions in HOMA-insulin resistance and HOMA-β-cell function and an increase in HOMA-insulin sensitivity, as assessed in 384 patients before and after HCV clearance. At multivariate analysis, HCV clearance emerged as independently associated with a reduced T2DM risk.

CONCLUSION

The results showed that HCV clearance by DAA treatment reduces T2DM incidence probably by restoring the HCV-induced alteration of glucose homeostasis mechanisms.

Chronic hepatitis C infection induces cardiovascular disease and type 2 diabetes: mechanisms and management

Despite the availability of effective treatments, hepatitis C virus (HCV) still remains a threat to public health. HCV is capable to trigger, behind liver damage, extrahepatic manifestations, including cardiovascular disease and type 2 diabetes (T2DM). A close association has been reported between HCV infection and cardiovascular disease due to imbalances in metabolic pathways and chronic inflammation. HCV through both direct and indirect mechanisms causes a higher incidence of ischemic stroke, acute coronary syndrome, heart failure and peripheral arterial disease. In addition, a higher risk of death from cardiovascular events has been showed in HCV patients. Insulin resistance is a hallmark of HCV infection and represents the link between HCV and T2DM, which is one of the most frequent HCV-associated extrahepatic manifestations. The pathological basis of the increased risk of T2DM in HCV infection is provided by the alterations of the molecular mechanisms of IR induced both by the direct effects of the HCV proteins, and by the indirect effects mediated by chronic inflammation, oxidative stress and hepatic steatosis. T2DM increases the risk of compensated and decompensate cirrhosis and hepatocellular carcinoma as well as increases the risk of cardiovascular disease, lower limb amputation and end stage renal disease. Current evidence suggests that HCV eradication reduces the incidence and mortality of cardiovascular disease and T2DM, further underling the importance of public health strategies for eradication the infection. The aim of this review was to update evidence and management of interaction between HCV, cardiovascular disease, and T2DM in the era of DAA treatment.

An estimation of the prevalence of occult HBV infection in Western Europe and in Northern America: A meta-analysis

Data on the prevalence of occult HBV infection (OBI) in Western Europe and in Northern America are few; hence, we conducted a systematic review and meta-analysis. All studies included had to fulfil the following inclusion criteria: (a) they investigated the prevalence of OBI (HBV DNA in liver tissue in HBsAg-negative subjects), (b) were carried out in Western Europe and in Northern America; (c) were available as a full-text manuscript, (d) written in English and (e) published up to December 2018. The exclusion criteria were as follows: (a) meta-analyses, letters, reviews, meeting abstracts or editorial comments; (b) studies investigating HBsAg-positive patients; (c) those investigating OBI outside Western Europe and in Northern America; and (d) to avoid small sample bias in the random-effects model, those enrolling less than five subjects. Thirty-four studies met the inclusion criteria, allowing a meta-analysis on 2729 patients. The overall prevalence of OBI was 34% (95% CI = 26%-42%), 28% (CI 95%: 12%-48%) in 329 subjects without chronic liver disease and 35% (95% CI 26%-44%) in 2400 patients with chronic liver disease. The prevalence of OBI was 51% (95% CI 40%-62%) in the 823 anti-HBc-positive subjects and 19% (95% CI 10%-30%) in the 1,041 anti-HBc-negative subjects. Evaluating the data from 17 studies comparing anti-HBc-positive and negative subjects, the prevalence of OBI was higher in the 641 anti-HBc-positive subjects than in the 1041 anti-HBc-negative (prevalence ratio = 2.29; 95% CI = 1.61-3.26, P < .001). This meta-analysis showed that in HBsAg-negative subjects the prevalence of OBI was high and was associated with anti-HBc positivity.

Metabolic and renal changes in patients with chronic hepatitis C infection after hepatitis C virus clearance by direct-acting antivirals

Background and Aim

The impact of hepatitis C virus (HCV) clearance by direct-acting antiviral agents (DAAs) on HCV-related extrahepatic manifestations is not well known. We evaluated the effect of viral clearance on metabolic and renal parameters.

Methods

In this prospective study, HCV patients who achieved a sustained virologic response (SVR) by DAAs were evaluated before, at the end, and 24 weeks after treatment for glycemic (serum glucose and insulin, HOMA-IR, HOMA-β, and HOMA-S) and lipid (serum cholesterol, triglycerides, low-density lipoprotein [LDL], high-density lipoprotein) metabolism and renal function (serum creatinine, estimated glomerular filtration rate [eGFR]).

Results

A total of 343 consecutive HCV patients were evaluated. At 24 weeks of post-follow-up, an increase in body mass index (BMI) was observed (P < 0.05). Regardless of hepatic fibrosis levels and BMI, a reduction in serum glucose (P = 0.001), HOMA-IR (P < 0.001) and HOMA-β (P < 0.001) and an increase in HOMA-S (P < 0.001) values were observed at 24 weeks after HCV clearance as compared to pretreatment values; 32.4% of patients with impaired fasting glucose normalized serum glucose values and 44.6% of diabetics showed an improvement in glycemic control. In contrast, serum cholesterol (P < 0.001) and LDL cholesterol (P < 0.001) values were increased. Renal function was improved with about 10% reduction of serum creatinine values (P < 0.02) and an increase of eGFR (P < 0.001). A baseline eGFR of ≤60 mL/min/1.73 m² was a negative predictor of renal function improvement. HCV clearance was an independent factor improving glucose metabolism and renal function.

Conclusions

Our study shows an occurrence of changes in metabolic and renal parameters in HCV patients with SVR, anticipating possible future clinical scenarios that the clinician must know for proper management.

Systematic review: chronic viral hepatitis and metabolic derangement

BACKGROUND

The liver has a critical role in the metabolism of glucose and lipids. Chronic hepatitis B virus (HBV) or hepatitis C virus (HCV) infection leads to a spectrum of liver disease including chronic hepatitis, cirrhosis and hepatocellular carcinoma. Metabolic syndrome (MetS) has a rising incidence owing to an epidemic of type 2 diabetes mellitus (T2DM) and obesity. Non-alcoholic fatty liver disease is a liver manifestation of MetS and has become the most common cause of chronic liver disease worldwide.

AIM

To summarise the interplay among hepatitis viruses, MetS and its components.

METHODS

We searched the literature about HBV, HCV infection, MetS, fatty liver and its components from PubMed.

RESULTS

With respect to the viral replication cycle, lipids are important mediators between viral entry and hepatocyte in HCV infection, but not in HBV infection. Thus, HCV infection is inversely associated with hyperlipidaemia and lipid rebound occurs following sustained viral response induced by interferon-based therapy or direct antiviral agents. In addition, HCV infection is positively associated with insulin resistance, hepatic steatosis, MetS and the risk of T2DM and atherosclerosis. In contrast, HBV infection may protect infected subjects from the development of MetS and hepatic steatosis. Accumulating evidence suggests that HBV infection is inversely associated with lipid metabolism, and exhibits no conclusive association with insulin resistance or the risk of T2DM and arteriosclerosis.

CONCLUSIONS

In patients with viral hepatitis and concurrent metabolic diseases, a multidisciplinary approach should be given rather than simply antiviral treatment.

Moderate to severe hepatic steatosis leads to overestimation of liver stiffness measurement in chronic hepatitis B patients without significant fibrosis

BACKGROUND

Liver stiffness measurement (LSM) by transient elastography is a noninvasive method for the diagnosis of hepatic fibrosis. The impact of hepatic steatosis on LSM remains to be explored.

AIM

To determine whether LSM is affected by hepatic steatosis in patients with chronic hepatitis B (CHB).

METHODS

Consecutive patients with biopsy-proven CHB were prospectively enrolled. Hepatic steatosis was classified by pathology as none (S0, <5%), mild (S1, 5%-33%), and moderate-severe (S2-3, >33%), and quantitatively by controlled attenuation parameter (CAP) as CAP S0 (≤247 dB/m), CAP S1 (248-267 dB/m) and CAP S2-3 (≥268 dB/m). Liver fibrosis was assessed by METAVIR classification and noninvasively by LSM.

RESULTS

The prevalence of non-alcoholic fatty liver disease (n = 223) in CHB patients (n = 593) was 37.6%. Forty-eight belonged to S2-3 and 127 belonged to CAP S2-3. In patients without significant fibrosis (F0-1), the median LSM (kPa) was 7.4 in S2-3 and 7.1 in CAP S2-3, which was significantly higher than that in S0/S1 (P = 0.005) and CAP S0/S1 (P = 0.003). No significant difference was found in significant fibrosis (F2-4). For LSM identifying significant fibrosis (F2-4), the negative predictive value was higher in CHB patients with CAP ≥ 268 compared to those with CAP < 268 (0.81 vs 0.73); the positive predictive value was lower in CAP ≥ 268 than its counterpart (0.65 vs 0.76).

CONCLUSIONS

Moderate-severe steatosis increased the LSM value in CHB patients without significant fibrosis. A CAP ≥ 268 did not affect LSM for ruling out, but it slightly affected LSM for ruling in significant fibrosis.

TRIAL REGISTRATION

ChiCTR-DDT-13003983.

Effect of hepatitis B virus on steatosis in hepatitis C virus co-infected subjects: A multi-centre study and systematic review

It remains unclear whether hepatitis B virus (HBV) infection may modify the severity of viral steatosis in patients coinfected with chronic hepatitis C virus (HCV). We examined the influence of coinfection with HBV on prevalence of steatosis in chronic hepatitis C in a multi-centre cohort of HBV-HCV subjects, and by performing a systematic review and meta-analysis of the literature. We centrally and blindly assessed steatosis prevalence and severity in a cohort of HBV-HCV coinfected subjects compared to HCV and HBV monoinfected controls and we performed a systematic review of studies addressing the prevalence of steatosis in HBV-HCV subjects compared to HCV controls. In the clinical cohort, we included 85 HBV-HCV, 69 HBV and 112 HCV subjects from 16 international centres. There was no significant difference in steatosis prevalence between the HBV-HCV and the HCV groups (33% vs 45%, P = .11). In subgroup analysis, lean HBV-HCV subjects with detectable HBV DNA had less steatosis than lean HCV subjects matched for HCV viremia (15% vs 45%, P = .02). Our literature search identified 5 additional studies included in a systematic review. Overall, prevalence of steatosis > 5% was similar in HBV-HCV infection compared to HCV (pooled odds ratio [OR] 0.91, 95% CI 0.53-1.6) although there was significant heterogeneity (I² 69%, P = .007). In conclusion, although the prevalence of steatosis is similar in HBV-HCV compared to HCV subjects, our analysis suggests that there may be an inhibitory effect of HCV-induced steatogenesis by HBV in certain subgroups of patients.

Hepatitis C virus clearance by direct-acting antiviral treatments and impact on insulin resistance in chronic hepatitis C patients

BACKGROUND AND AIM

Chronic hepatitis C virus (HCV), particularly genotype 1, is associated with insulin resistance (IR) and diabetes. This study evaluated the impact of HCV clearance by all-oral direct-acting antiviral treatments on IR and glycemic control.

METHODS

Included in this prospective case-control study were 133 consecutive HCV-genotype 1 patients with advance liver fibrosis (F3-F4) without type 2 diabetes. Sixty eight were treated with direct-acting antiviral and 65 were untreated. Liver fibrosis was assessed by transient elastography. Pre-treatment, end-treatment, and 3 months post-treatment withdrawal IR homeostasis was assessed by homeostatic model assessment (HOMA)-IR, HOMA-S, and HOMA-B.

RESULTS

At baseline, treated, and untreated patients showed similar liver fibrosis levels, HOMA-IR was 4.90 ± 4.62 and 4.64 ± 5.62, respectively. HOMA-IR correlated with HCV RNA levels. At the end of treatment, all patients cleared HCV RNA, regardless of liver fibrosis and body mass index, and a reduction in HOMA-IR at 2.42 ± 1.85 was showed (P < 0.001); in addition, increased insulin sensitivity, decreased insulin secretion, reduction of serum glucose, and insulin levels were observed. Data were confirmed 3 months after treatment withdrawal in the 65 patients who cleared HCV. No variation occurred in untreated patients. Overall, 76.5% of sustained virologic response patients showed IR improvements, of which 41.2% normalized IR. Improvement of IR was strictly associated with HCV clearance; however, patients with the highest levels of fibrosis remain associated with some degree of IR.

CONCLUSIONS

The data underline a role of HCV in development of IR and that viral eradication reverses IR and improves glycemic control and this could prevent IR-related clinical manifestations and complications.

Investigation of the roles of trace elements during hepatitis C virus infection using protein-protein interactions and a shortest path algorithm

BACKGROUND

Hepatitis is a type of infectious disease that induces inflammation of the liver without pinpointing a particular pathogen or pathogenesis. Type C hepatitis, as a type of hepatitis, has been reported to induce cirrhosis and hepatocellular carcinoma within a very short amount of time. It is a great threat to human health. Some studies have revealed that trace elements are associated with infection with and immune rejection against hepatitis C virus (HCV). However, the mechanism underlying this phenomenon is still unclear.

METHODS

In this study, we aimed to expand our knowledge of this phenomenon by designing a computational method to identify genes that may be related to both HCV and trace element metabolic processes. The searching procedure included three stages. First, a shortest path algorithm was applied to a large network, constructed by protein-protein interactions, to identify potential genes of interest. Second, a permutation test was executed to exclude false discoveries. Finally, some rules based on the betweenness and associations between candidate genes and HCV and trace elements were built to select core genes among the remaining genes.

RESULTS

12 lists of genes, corresponding to 12 types of trace elements, were obtained. These genes are deemed to be associated with HCV infection and trace elements metabolism.

CONCLUSIONS

The analyses indicate that some genes may be related to both HCV and trace element metabolic processes, further confirming the associations between HCV and trace elements. The method was further tested on another set of HCV genes, the results indicate that this method is quite robustness.

GENERAL SIGNIFICANCE

The newly found genes may partially reveal unknown mechanisms between HCV infection and trace element metabolism. This article is part of a Special Issue entitled "System Genetics" Guest Editor: Dr. Yudong Cai and Dr. Tao Huang.

Hepatitis C Virus, Insulin Resistance, and Steatosis

Hepatitis C virus (HCV) is one of the main causes of liver disease worldwide. Liver steatosis is a common finding in many hepatic and extrahepatic disorders, the most common being metabolic syndrome (MS). Over time, it has been shown that the frequent coexistence of these two conditions is not coincidental, since many epidemiological, clinical, and experimental studies have indicated HCV to be strongly associated with liver steatosis and numerous metabolic derangements. Here, we present an overview of publications that provide clinical evidence of the metabolic effects of HCV and summarize the available data on the pathogenetic mechanisms of this association. It has been shown that HCV infection can induce insulin resistance (IR) in the liver and peripheral tissues through multiple mechanisms. Substantial research has suggested that HCV interferes with insulin signaling both directly and indirectly, inducing the production of several proinflammatory cytokines. HCV replication, assembly, and release from hepatocytes require close interactions with lipid droplets and host lipoproteins. This modulation of lipid metabolism in host cells can induce hepatic steatosis, which is more pronounced in patients with HCV genotype 3. The risk of steatosis depends on several viral factors (including genotype, viral load, and gene mutations) and host features (visceral obesity, type 2 diabetes mellitus, genetic predisposition, medication use, and alcohol consumption). HCV-related IR and steatosis have been shown to have a remarkable clinical impact on the prognosis of HCV infection and quality of life, due to their association with resistance to antiviral therapy, progression of hepatic fibrosis, and development of hepatocellular carcinoma. Finally, HCV-induced IR, oxidative stress, and changes in lipid and iron metabolism lead to glucose intolerance, arterial hypertension, hyperuricemia, and atherosclerosis, resulting in increased cardiovascular mortality.

HBV-related chronic liver disease and insulin resistance

The liver is the major organ regulating glucose metabolism. When liver injury occurs, glucose metabolism disturbance and insulin resistance (IR) may develop, which can even cause the development of hepatogenic diabetes. The correlation between viral hepatitis, liver cirrhosis and diabetes has become a hot research topic in recent years. This paper reviews the progress in research of hepatitis B virus (HBV) infection and early predictors of diabetes. We give a brief introduction to the concept of IR and its causes, and discuss the relationship of HBV infection, HBV and HCV coinfection, and hepatitis associated cirrhosis with IR. We also describe the possible mechanisms for IR in HBV infected people. Besides, we discuss the impact of IR on prognosis of HBV related chronic liver diseases, mainly fatty, liver fibrosis, and liver cancer. The clinical treatment of patients with HBV infection and IR is also discussed.

Hepatitis C virus markers in infection by hepatitis C virus: In the era of directly acting antivirals

About 130-170 million people are infected with the hepatitis C virus (HCV) worldwide and more than 350000 people die each year of HCV-related liver diseases. The combination of pegylated interferon (Peg-IFN) and ribavirin (RBV) was recommended as the treatment of choice for chronic hepatitis C for nearly a decade. In 2011 the directly acting antivirals (DAA) HCV NS3/4A protease inhibitors, telaprevir and boceprevir, were approved to treat HCV-genotype-1 infection, each in triple combination with Peg-IFN and RBV. These treatments allowed higher rates of SVR than the double Peg-IFN + RBV, but the low tolerability and high pill burden of these triple regimes were responsible for reduced adherence and early treatment discontinuation. The second and third wave DAAs introduced in 2013-2014 enhanced the efficacy and tolerability of anti-HCV treatment. Consequently, the traditional indicators for disease management and predictors of treatment response should be revised in light of these new therapeutic options. This review article will focus on the use of the markers of HCV infection and replication, of laboratory and instrumental data to define the stage of the disease and of predictors, if any, of response to therapy in the DAA era. The article is addressed particularly to physicians who have patients with hepatitis C in care in their everyday clinical practice.