Hepatitis C virus infection: evidence for an association with type 2 diabetes

Extrahepatic manifestations of hepatitis C infection: navigating CHASM

This article describes the importance of extrahepatic systemic manifestations of chronic hepatitis C virus (HCV) infection. While most HCV literature focuses on liver injury and fibrosis progression, a spectrum of systemic disease processes, collectively called C hepatitis-associated systemic manifestations (CHASMs), are present in a high proportion of infected persons. These include thyroid disease (Hashimoto's thyroiditis, Graves disease, and thyroid cancer), cardiovascular disease (atherosclerosis, carotid artery disease, and coronary artery disease), renal disease (MPGN and glomerulosclerosis), eye disease (Mooren's ulcers and sicca syndrome), skin disease (PCT, vasculitis, and lichen planus), lymphomas (NHL and splenic T-cell), and diabetes. Mechanistic understanding of how HCV leads to CHASM processes could lead to development of new interventions. The role of early HCV treatment and cure may result in preventive strategies for a variety of complex disease states. Key Points • Systemic extrahepatic complications of HCV comprise a spectrum of disease states in many organs and systems.• Effective treatment of HCV may reduce or eliminate some but not all of these systemic complications.• Further research into early treatment intervention as a prevention strategy for systemic disease is warranted.

Cytokines and HCV-related autoimmune disorders

Cytokines are intercellular mediators involved in viral control and liver damage being induced by infection with hepatitis C virus (HCV). The complex cytokine network operating during initial infection allows a coordinated, effective development of both innate and adaptive immune responses. However, HCV interferes with cytokines at various levels and escapes immune response by inducing a T-helper (Th)2/T cytotoxic 2 cytokine profile. Inability to control infection leads to the recruitment of inflammatory infiltrates into the liver parenchyma by interferon (IFN)-γ-inducible CXC chemokine ligand (CXCL)9, -10, and -11 chemokines, which results in sustained liver damage and eventually in liver cirrhosis. The most important systemic HCV-related extrahepatic diseases-mixed cryoglobulinemia, lymphoproliferative disorders, thyroid autoimmune disorders, and type 2 diabetes-are associated with a complex dysregulation of the cytokine/chemokine network, involving proinflammatory and Th1 chemokines. The therapeutical administration of cytokines such as IFN-α may result in viral clearance during persistent infection and revert this process. Theoretically agents that selectively neutralize CXCL10 could increase patient responsiveness to traditional IFN-based HCV therapy. Several studies have reported IL-28B polymorphisms and circulating CXCL10 may be a prognostic markers for HCV treatment efficacy in HCV genotype 1 infection.

Hepatitis C virus infection and type 1 and type 2 diabetes mellitus

Hepatitis C virus (HCV) infection and diabetes mellitus are two major public health problems that cause devastating health and financial burdens worldwide. Diabetes can be classified into two major types: type 1 diabetes mellitus (T1DM) and T2DM. T2DM is a common endocrine disorder that encompasses multifactorial mechanisms, and T1DM is an immunologically mediated disease. Many epidemiological studies have shown an association between T2DM and chronic hepatitis C (CHC) infection. The processes through which CHC is associated with T2DM seem to involve direct viral effects, insulin resistance, proinflammatory cytokines, chemokines, and other immune-mediated mechanisms. Few data have been reported on the association of CHC and T1DM and reports on the potential association between T1DM and acute HCV infection are even rarer. A small number of studies indicate that interferon-α therapy can stimulate pancreatic autoimmunity and in certain cases lead to the development of T1DM. Diabetes and CHC have important interactions. Diabetic CHC patients have an increased risk of developing cirrhosis and hepatocellular carcinoma compared with non-diabetic CHC subjects. However, clinical trials on HCV-positive patients have reported improvements in glucose metabolism after antiviral treatment. Further studies are needed to improve prevention policies and to foster adequate and cost-effective programmes for the surveillance and treatment of diabetic CHC patients.

CXCR3, CXCL10 and type 1 diabetes

Type 1 diabetes (T1D) is due to antigen-specific assaults on the insulin producing pancreatic β-cells by diabetogenic T-helper (Th)1 cells. (C-X-C motif) ligand (CXCL)10, an interferon-γ inducible Th1 chemokine, and its receptor, (C-X-C motif) receptor (CXCR)3, have an important role in different autoimmune diseases. High circulating CXCL10 levels were detected in new onset T1D patients, in association with a Th1 autoimmune response. Furthermore β-cells produce CXCL10, under the influence of Th1 cytokines, that suppresses their proliferation. Viral β-cells infections induce cytokines and CXCL10 expression, inducing insulin-producing cell failure in T1D. CXCL10/CXCR3 system plays a critical role in the autoimmune process and in β-cells destruction in T1D. Blocking CXCL10 in new onset diabetes seems a possible approach for T1D treatment.

Type 2 diabetes mellitus and the risk of hepatitis C virus infection: a systematic review

The aim of this study was to evaluate the relationship between type 2 diabetes mellitus (T2DM) and hepatitis C virus (HCV) infection and to examine whether T2DM enhances the risk of HCV infection compared with the risk in the general population. We followed standard guidelines to perform a meta-analysis. The associated literature was selected based on the established inclusion criteria. The summary odds ratio (OR) and 95% confidence interval (95% CI) were used to investigate the strength of the association. Through electronic database and manual searching, 22 studies were identified for the final analysis, which included a total of 78,051 individuals. Based on the random effects model, the meta-analysis results showed that patients with T2DM were at a higher risk of acquiring HCV infection than non-T2DM patients (summary OR = 3.50, 95% CI = 2.54–4.82, I² = 82.3%). Based on the current limited evidence, this study suggests that T2DM is associated with increased susceptibility to HCV infection.

Community-based cross-sectional study: the association of lipids with hepatitis C seropositivity and diabetes mellitus

BACKGROUND AND AIMS

Hepatitis C virus (HCV) infection is reported to be associated with or to cause type 2 diabetes mellitus (T2DM). Our study aimed to elucidate the role of triglyceride (TG) and cholesterol (CHOL) levels in the association between anti-HCV seropositivity and T2DM in an HCV-endemic area.

METHODS

We analyzed a computerized dataset of 56 338 residents from a community-based comprehensive screening program in Tainan County in southern Taiwan. Fasting glucose, anti-HCV status, hepatitis B surface antigen (HBsAg) status, platelet counts, TG levels, CHOL levels, age, gender, and body mass index were included in the analyses. Multivariate logistic analysis was used to identify factors independently associated with T2DM.

RESULTS

Older age, being overweight, thrombocytopenia, hypertriglyceridemia, hypercholesterolemia, anti-HCV seropositivity, and HBsAg seronegativity were common factors independently associated with diabetes. Among all models of multiple logistic regression analysis used for identifying factors independently associated with T2DM, anti-HCV seropositivity was only identified in the models that included either hypertriglyceridemia or hypercholesterolemia. When subjects were divided into hyperlipidemia (CHOL, > 200 or TG, > 150 mg/dL; n = 33 393) or non-hyperlipidemia subgroups (CHOL, < 200 and TG, < 150 mg/dL; n = 22 945), anti-HCV seropositivity was identified as an independent factor only in the non-hyperlipidemia subgroup. The odds ratio was 1.35, with a 95% confidence interval of 1.17-1.55.

CONCLUSIONS

This study demonstrates that the lipid level is associated with the relationship between T2DM and anti-HCV seropositivity in non-hyperlipidemic individuals. However, the relationship between HCV and T2DM did not exist when the lipid level was not included in the analysis.

Cytokines and HCV-related disorders

Cytokines are intercellular mediators involved in viral control and liver damage being induced by infection with hepatitis C virus (HCV). The complex cytokine network operating during initial infection allows a coordinated, effective development of both innate and adaptive immune responses. However, HCV interferes with cytokines at various levels and escapes immune response by inducing a T-helper (Th)2/T cytotoxic 2 cytokine profile. Inability to control infection leads to the recruitment of inflammatory infiltrates into the liver parenchyma by interferon (IFN)-gamma-inducible CXC chemokine ligand (CXCL)-9, -10, and -11 chemokines, which results in sustained liver damage and eventually in liver cirrhosis. The most important systemic HCV-related extrahepatic diseases--mixed cryoglobulinemia, lymphoproliferative disorders, thyroid autoimmune disorders, and type 2 diabetes--are associated with a complex dysregulation of the cytokine/chemokine network, involving proinflammatory and Th1 chemokines. The therapeutical administration of cytokines such as IFN-alpha may result in viral clearance during persistent infection and reverts this process.

Impact of preexisting diabetes mellitus on outcome after liver transplantation in patients with hepatitis B virus-related liver disease

BACKGROUND

Preexisting diabetes mellitus (DM) has been reported to have an adverse consequence on patient prognosis after liver transplantation in the West. So far, there are few reports on the effect of preexisting DM on outcome of liver transplant recipients with HBV infection.

AIMS

We aimed to examine the impact of preexisting DM on post-transplant outcome in Chinese patients with HBV-related liver disease.

METHODS

The post-transplant morbidities and patient survival were compared between 48 diabetes patients (DM group) and 96 non-diabetes patients (control group) matched for age, gender, primary disease and model for end-stage liver diseases score. The DM group was further divided into hyperglycemia patients (fasting blood glucose >8.0 mmol/L, n = 22) and non-hyperglycemia patients (fasting blood glucose ≤8.0 mmol/L, n = 26).

RESULTS

Patient characteristics were comparable between both groups, except a higher incidence of hepatic encephalopathy in the DM group than that in the control group (22.9% vs. 10.4%, P = 0.045). The incidences of post-transplant complications and patient survival did not differ significantly between the DM and control groups, or between non-hyperglycemia patients and their matched case controls. Hyperglycemia patients showed a higher incidence of post-transplant sepsis (18.2% vs. 2.3%, P = 0.039) and biliary complications (31.8% vs. 6.8%, P = 0.012) than their matched case controls.

CONCLUSIONS

Preexisting DM is not a contraindication for liver transplantation in patients with HBV-related liver disease. A tight control of blood glucose to a level of ≤8.0 mmol/L was necessary to reduce the risk of complications after liver transplantation.

Association of hepatitis C virus infection and diabetes in central Tunisia

AIM: To investigate hepatitis C virus (HCV) seroprevalence in Tunisian patients with diabetes mellitus and in a control group.

METHODS: A cross-sectional study was conducted to determine the HCV seroprevalence in 1269 patients with diabetes (452 male, 817 female) and 1315 non-diabetic patients, attending health centers in Sousse, Tunisia. HCV screening was performed in both groups using a fourth-generation enzyme immunoassay.

RESULTS: In the diabetic group, 17 (1.3%) were found to be HCV-infected compared with eight (0.6%) in the control group, although the difference was not significant (P = 0.057). Quantitative PCR was performed in 20 patients. Eleven patients were positive and showed HCV genotype 1b in all cases.

CONCLUSION: Frequency of HCV antibodies was low in patients with diabetes and in the control group in central Tunisia, with no significant difference between the groups.

Endocrine manifestations of hepatitis C virus infection

Chronic infection with hepatitis C virus (HCV) can result in both hepatic and extrahepatic disease and endocrine dysfunction represents an important class of HCV-related extrahepatic disease. The most frequently occurring--and clinically important--of these endocrine disorders are thyroid disease and type 2 diabetes mellitus. In this Review, we evaluate the evidence in support of a link between HCV infection and endocrine-system dysfunction, and discuss potential pathophysiological mechanisms. A meta-analysis of the literature has revealed significant associations between chronic HCV infection, thyroid autoimmunity and hypothyroidism. Furthermore, a high prevalence of thyroid cancer has been reported in HCV-positive patients. Several clinicoepidemiological studies have demonstrated that chronic HCV infection could lead to the development of type 2 diabetes mellitus, possibly as a result of HCV-induced metabolic disturbances. Some researchers have postulated that a type 1 T-helper -cell mediated immune response underpins the association of chronic HCV infection with endocrine disease. Indeed, the available data suggest that a common immunological, type 1 T-helper cell pattern of cytokine expression and activation (via interferon-gamma) could provide the pathophysiological basis for this association. Nonetheless, additional studies will be necessary to elucidate fully all the mechanisms involved in HCV-related endocrine dysfunction.

Immunopathogenesis of HCV-related endocrine manifestations in chronic hepatitis and mixed cryoglobulinemia

Hepatitis C Virus (HCV) is known to be responsible for both hepatic and extrahepatic diseases (HCV-related extrahepatic diseases = HCV-EHDs). The most important systemic HCV-EHDs are mixed cryoglobulinemia and lymphoproliferative disorders, while the most frequent and clinically important endocrine HCV-EHDs are thyroid disorders and type 2 diabetes mellitus (T2D). From a meta-analysis of the literature a significant association between HCV infection and thyroid autoimmunity and hypothyroidism has been reported. A high prevalence of thyroid cancer has been reported, too. Furthermore, several clinical epidemiologic studies have reported that HCV infection is associated to T2D. Many studies have linked Th1 immune response with HCV infection, thyroid autoimmunity, or diabetes. These findings suggest that a possible common immunological Th1 pattern could be the pathophysiological base of the association of HCV-EHDs, with thyroid autoimmunity and T2D. In fact, HCV infection of thyrocytes or beta-cells may act by upregulating CXCL10 secretion in these cells that is responsible for Th1 lymphocyte recruitment. Th1 response leads to increased IFNgamma and TNFalpha production that in turn stimulates CXCL10 secretion by the target cells, thus perpetuating the immune cascade. This process may lead to the appearance of thyroid autoimmune disorders or T2D in genetically predisposed subjects.

Hepatitis C viremia increases the association with type 2 diabetes mellitus in a hepatitis B and C endemic area: an epidemiological link with virological implication

OBJECTIVES

There is growing evidence with regard to the association between hepatitis C virus (HCV) infection and type 2 diabetes mellitus (T2DM). However, the mutual link and related virological implication have not been fully clarified. The impact of hepatitis B virus (HBV) infection on the epidemiological link remains unclear. This study aimed to elucidate the link between T2DM and viral hepatitis infections, especially HCV infection. It also aimed to analyze the associated virological characteristics and implication.

METHODS

Cross-sectional analysis of a computer-sampling survey among 10,975 participants (aged 40-65 yr) was performed in an area endemic for HBV and HCV infections in Taiwan. Outcome measures included prevalence of T2DM among different groups of viral hepatitis infection, and comparison of related biochemical and virological profiles.

RESULTS

Of 10,975 participants studied, 9,932 eligible participants were analyzed. The prevalence of T2DM, seropositivity for HBV surface antigen (HBsAg) and HCV antibodies (anti-HCV), and HCV viremia was 12.5%, 13.1%, 6.5%, and 4.8%, respectively. Prevalence of HCV viremia showed significant difference between T2DM and non-T2DM subjects (6.9% vs 4.5%, P<0.001), whereas anti-HCV seropositivity showed borderline significance (7.8% vs 6.3%, P=0.047). There was no HCV genotype-specific difference between HCV genotype 1 and 2 in the association with T2DM. On the other side, the prevalence of HBsAg (+) did not differ between T2DM and non-T2DM subjects (12.5% vs 13.9%, P=0.19). The prevalence of T2DM among HCV viremic subjects (18.0%, 86/478) was significantly higher than HBsAg (+) subjects (11.4%, 155/1,363, P=0.001) and those negative for both viral hepatitis markers (12.5%, 997/8,004, P=0.001). Multivariate logistic regression analyses showed that HCV viremia was the leading significant factor associated with T2DM, followed by male gender, hypertension, body mass index, and age.

CONCLUSIONS

HBV infection did not increase the association with T2DM. A significant mutual link between T2DM and HCV viremia existed in this HBV/HCV endemic area. There was no HCV genotype-specific difference between HCV genotype 1 and 2 in the association with T2DM.