Impaired IRS-1/PI3-kinase signaling in patients with HCV: a mechanism for increased prevalence of type 2 diabetes

Research progress on the association of insulin resistance with type 2 diabetes mellitus and Alzheimer's disease

Type 2 diabetes mellitus (T2DM) is a metabolic disorder that is characterized by insulin resistance and hyperglycemia. It is also known to be a risk factor for Alzheimer's disease (AD). Insulin plays a crucial role in regulating the body's metabolism and is responsible for activating the Phosphoinotide-3-Kinase (PI3K)/Protein Kinase B (Akt) signaling pathway. This pathway is activated when insulin binds to the insulin receptor on nerve cells, and it helps regulate the metabolism of glucose and lipids. Dysfunction in the insulin signaling pathway can lead to a decrease in brain insulin levels and insulin sensitivity, thereby inducing disruptions in insulin signal transduction and leading to disorders in brain energy metabolism. Moreover, these dysfunctions also contribute to the accumulation of β-amyloid (Aβ) deposition and the hyperphosphorylation of Tau protein, both of which are characteristic features of AD. Therefore, this article focuses on insulin resistance to reveal the complex mechanism between brain insulin resistance and AD occurrence in T2DM. On this basis, this article further summarizes the biological effects and mechanisms of antidiabetic drugs on the two diseases, aiming to provide new ideas for the discovery of drugs for the treatment of T2DM combined with AD.

Hepatitis C Infection Is Not a Cardiovascular Risk Factor in Young Adults

Background: Cardiovascular diseases are one of the leading causes of hospitalization and death in Poland and around the world and are still an ongoing problem for modern medicine. Despite advances in diagnosis and treatment, both conservative and invasive, the prevention of cardiovascular disease directed at reducing risk factors remains a problem. The main classical risk factors for the development of cardiovascular disease in Poland include hypertension, lipid disorders, obesity, diabetes and smoking. A new non-classical risk factor is HCV infection. Most of the studies on the impact of HCV infection on cardiovascular disease involve elderly populations with long-term infections and advanced liver fibrosis. Methods: Hence, we set out to analyze the prevalence of risk factors and cardiovascular disease in a population of young adults under 45 years of age infected with HCV, according to gender, HCV genotype and the duration of infection. The study group consisted of 217 patients of both sexes aged 21 to 45 years (mean age 36 years). Results: No cardiovascular disease was found among the young adults infected with HCV in the study group. The most common risk factor was cigarette smoking, which affected 20.7% of the subjects, followed by hypertension (12%) and diabetes mellitus (5.5%); the prevalence was lower than in the general population. Most of the patients were characterized as overweight, with a mean BMI of 26.39 kg/m2. The mean values of other metabolic parameters-total cholesterol, LDL, HDL, uric acid and glucose-were within the population norm. The mean value of CRP was 1.43, which may indicate a moderate cardiovascular risk. Conclusions: Based on the conducted research, it was found that HCV infection in young individuals was not a risk factor for cardiovascular diseases, and the prevalence of risk factors was similar to that in the general population. The effect of HCV on the increase in C-reactive protein requires further study. The early detection of HCV infection and treatment can be considered as a prevention of cardiovascular disease.

Hepatitis C virus antibody seropositivity is associated with albuminuria but not peripheral artery disease in patients with type 2 diabetes

Hepatitis C virus (HCV) infection is prevalent in patients with type 2 diabetes mellitus (DM). We aimed to investigate whether HCV antibody (Ab) seropositivity is associated with diabetic micro- and macro-vascular diseases. In this hospital-based cross-sectional study, we retrospectively collected data from patients who participated in the diabetes pay-for-performance program and underwent HCV Ab screening in the annual comprehensive assessment between January 2021 and March 2022. We examined the relationships of HCV Ab seropositivity with the spot urinary albumin-to-creatinine ratio (UACR) and ankle-brachial index (ABI) in patients aged ≥ 50 years with type 2 DM. A total of 1758 patients were enrolled, and 85 (4.83%) of the enrolled patients had HCV Ab seropositivity. Multivariable regression analyses revealed that albuminuria showed a dose-dependent association with HCV Ab seropositivity (UACR [30-299 mg/g]: odds ratio [OR] = 1.463, 95% confidence interval [CI] 0.872‒2.456); UACR [≥ 300 mg/g]: OR = 2.300, 95% CI 1.160‒4.562; P for trend = 0.015) when compared with normal albuminuria (UACR < 30 mg/g). However, the proportion of patients with peripheral arterial disease, defined as an ABI ≤ 0.9, was not significantly different between the groups with and without HCV Ab seropositivity (3.5% vs. 3.9%, P = 0.999). In conclusion, severely increased albuminuria, but not the ABI, showed a significant association with HCV Ab seropositivity in patients aged ≥ 50 years with type 2 DM.

TASL, TADE, and DAROC consensus for the screening and management of hepatitis C in patients with diabetes

Diabetes mellitus (DM) and hepatitis C virus (HCV) infection are prevalent diseases globally and emerging evidence demonstrates the bidirectional association between the two diseases. Direct-acting antivirals (DAAs) for HCV have a high treatment success rate and can significantly reduce the risks of short and long-term complications of HCV infection. However, despite the evidence of the association between diabetes and HCV and the benefits of anti-HCV treatment, previously published guidelines did not focus on the universal HCV screening for patients with diabetes and their subsequent management once confirmed as having HCV viremia. Nonetheless, screening for HCV among patients with diabetes will contribute to the eradication of HCV infection. Thus, the three major Taiwan medical associations of diabetes and liver diseases endorsed a total of 14 experts in the fields of gastroenterology, hepatology, diabetology, and epidemiology to convene and formulate a consensus statement on HCV screening and management among patients with diabetes. Based on recent studies and guidelines as well as from real-world clinical experiences, the Taiwan experts reached a consensus that provides a straightforward approach to HCV screening, treatment, and monitoring of patients with diabetes.

Unraveling the Molecular Mechanisms Involved in HCV-Induced Carcinogenesis

Cancer induced by a viral infection is among the leading causes of cancer. Hepatitis C Virus (HCV) is a hepatotropic oncogenic positive-sense RNA virus that leads to chronic infection, exposing the liver to a continuous process of damage and regeneration and promoting hepatocarcinogenesis. The virus promotes the development of carcinogenesis through indirect and direct molecular mechanisms such as chronic inflammation, oxidative stress, steatosis, genetic alterations, epithelial-mesenchymal transition, proliferation, and apoptosis, among others. Recently, direct-acting antivirals (DAAs) showed sustained virologic response in 95% of cases. Nevertheless, patients treated with DAAs have reported an unexpected increase in the early incidence of Hepatocellular carcinoma (HCC). Studies suggest that HCV induces epigenetic regulation through non-coding RNAs, DNA methylation, and chromatin remodeling, which modify gene expressions and induce genomic instability related to HCC development that persists with the infection's clearance. The need for a better understanding of the molecular mechanisms associated with the development of carcinogenesis is evident. The aim of this review was to unravel the molecular pathways involved in the development of carcinogenesis before, during, and after the viral infection's resolution, and how these pathways were regulated by the virus, to find control points that can be used as potential therapeutic targets.

Prevalence and clinical characteristics of patients with metabolic dysfunction-associated fatty liver disease with hepatitis C virus infection-a population-based study

BACKGROUND

Metabolic-associated fatty liver disease (MAFLD) was proposed in 2020 to identify fatty liver disease associated with metabolic risks. Metabolic abnormalities with hepatitis C virus (HCV) and MAFLD frequently co-exist. However, data on the co-existence are still lacking.

AIM

To explore the prevalence and characteristics of metabolic profiles among a large cohort of patients with HCV infection between 2007 and 2020 based on new diagnostic criteria METHODS: We recruited 288,222 patients with chronic HCV infection with demographic data, laboratory parameters, and ultrasound from a web-based registry of the National Committee for Control of Viral Hepatitis in Egypt from 2007 to 2020.

RESULTS

Among the participants, 41.9% (95% CI: 41.69-42.05) met diagnostic criteria for MAFLD, with a significant increase in the period 2014-2020 compared to 2007-2013 (43.3% vs. 19%, respectively). Participants with MAFLD had a high prevalence of obesity, diabetes mellitus and hypertension. The prevalences increased significantly over time (obesity: 66.7% vs. 76.9%, p < 0.01; diabetes mellitus: 14.6% vs. 31.5%, p < 0.01; hypertension: 0.9% vs. 7.6%, p < 0.01; prediabetes: 28.8% vs. 25.9%, p < 0.01) for the periods 2007-2013 and 2014-2020, respectively. The percentage of advanced fibrosis by fibrosis-4 index (FIB-4) and NAFLD fibrosis score (NFS) was significantly higher in participants with MAFLD during 2014-2020 than during 2007-2013 (FIB-4; 18.4% vs. 8% and NFS; 17.1% vs. 7%).

CONCLUSION

MAFLD is highly prevalent in patients with HCV infection and has risen over time. This rising prevalence parallels the alarming rise in obesity, diabetes mellitus and hypertension. Early detection of metabolic dysfunction in patients with HCV infection is recommended to prevent MAFLD progression.

HCV infection characteristics, treatment uptake and outcomes in patient with diabetes mellitus

BACKGROUND

The interplay between HCV, DM, and DAA therapy is poorly understood. We compared HCV infection characteristics, treatment uptake, and treatment outcomes in patients with and without DM.  METHODS: A retrospective cohort study was conducted using data from The Ottawa Hospital Viral Hepatitis Program. Statistical comparisons between diabetes and non-diabetes were made using χ² and t-tests. Logistic regression analyses were performed to assess predictors of DM and SVR.

RESULTS

One thousand five hundred eighty-eight HCV patients were included in this analysis; 9.6% had DM. Patients with DM were older and more likely to have cirrhosis. HCC and chronic renal disease were more prevalent in the DM group. Treatment uptake and SVR were comparable between groups. Regression analysis revealed that age and employment were associated with achieving SVR. Post-SVR HCC was higher in DM group.

CONCLUSION

The high prevalence of DM in our HCV cohort supports screening. Further assessment is required to determine if targeted, early DAA treatment reduces DM onset, progression to cirrhosis and HCC risk. Further studies are needed to determine if optimization of glycemic control in this population can lead to improved liver outcomes.

Prioritization of cancer driver gene with prize-collecting steiner tree by introducing an edge weighted strategy in the personalized gene interaction network

Background

Cancer is a heterogeneous disease in which tumor genes cooperate as well as adapt and evolve to the changing conditions for individual patients. It is a meaningful task to discover the personalized cancer driver genes that can provide diagnosis and target drug for individual patients. However, most of existing methods mainly ranks potential personalized cancer driver genes by considering the patient-specific nodes information on the gene/protein interaction network. These methods ignore the personalized edge weight information in gene interaction network, leading to false positive results.

Results

In this work, we presented a novel algorithm (called PDGPCS) to predict the Personalized cancer Driver Genes based on the Prize-Collecting Steiner tree model by considering the personalized edge weight information. PDGPCS first constructs the personalized weighted gene interaction network by integrating the personalized gene expression data and prior known gene/protein interaction network knowledge. Then the gene mutation data and pathway data are integrated to quantify the impact of each mutant gene on every dysregulated pathway with the prize-collecting Steiner tree model. Finally, according to the mutant gene’s aggregated impact score on all dysregulated pathways, the mutant genes are ranked for prioritizing the personalized cancer driver genes. Experimental results on four TCGA cancer datasets show that PDGPCS has better performance than other personalized driver gene prediction methods. In addition, we verified that the personalized edge weight of gene interaction network can improve the prediction performance.

Conclusions

PDGPCS can more accurately identify the personalized driver genes and takes a step further toward personalized medicine and treatment. The source code of PDGPCS can be freely downloaded from https://github.com/NWPU-903PR/PDGPCS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12859-022-04802-y.

Hepatitis C Virus, Insulin Resistance, and Diabetes: A Review

Hepatitis C virus (HCV) infection and diabetes mellitus (DM) are two chronic diseases that are a cause of significant health and economic burdens worldwide. HCV is associated with the development of insulin resistance (IR) and diabetes mellitus (DM). The mechanisms through which HCV induces IR and DM include direct viral effects, pro-inflammatory cytokines and other immune-mediated processes. Type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM) are both chronic diseases that involve impaired glucose homeostasis, albeit through different mechanisms. T1DM is an autoimmune disease that leads to the destruction of pancreatic beta cells resulting in insulin deficiency. In T2DM, a combination of peripheral insulin resistance and irregular production of insulin eventually lead to beta cell destruction and insulin insufficiency. Both type 1 and type 2 DM etiologies involve a combination of genetic and environmental factors. The data on HCV and T1DM association is limited, unlike T2DM, where a large body of evidence linking HCV to T2DM is available. Here, we intend to outline the current state of knowledge on HCV, IR, and DM. This article is protected by copyright. All rights reserved.

Metabolic dysfunction and cancer in HCV: Shared pathways and mutual interactions

HCV hijacks many host metabolic processes in an effort to aid viral replication. The resulting hepatic metabolic dysfunction underpins many of the hepatic and extrahepatic manifestations of chronic hepatitis C (CHC). However, the natural history of CHC is also substantially influenced by the host metabolic status: obesity, insulin resistance and hepatic steatosis are major determinants of CHC progression toward hepatocellular carcinoma (HCC). Direct-acting antivirals (DAAs) have transformed the treatment and natural history of CHC. While DAA therapy effectively eradicates the virus, the long-lasting overlapping metabolic disease can persist, especially in the presence of obesity, increasing the risk of liver disease progression. This review covers the mechanisms by which HCV tunes hepatic and systemic metabolism, highlighting how systemic metabolic disturbance, lipotoxicity and chronic inflammation favour disease progression and a precancerous niche. We also highlight the therapeutic implications of sustained metabolic dysfunction following sustained virologic response as well as considerations for patients who develop HCC on the background of metabolic dysfunction.

Glycemic Control in Patients Undergoing Treatment With Paritaprevir/Ombitasvir/Ritonavir and Dasabuvir for Chronic Hepatitis C Infection

BACKGROUND/AIM

Patients with hepatitis C virus (HCV)-associated cirrhosis are more prone to developing type 2 diabetes mellitus than patients with any other etiology of cirrhosis. The main objective of this study was to evaluate the impact of all oral antiviral treatment with ritonavir-boosted paritaprevir/ombitasvir and dasabuvir (OBV/PTV/r + DSV) in patients with chronic genotype 1b HCV infection.

PATIENTS AND METHODS

We retrospectively evaluated 806 patients who underwent antiviral therapy between December 2015 and July 2019. The laboratory data analyzed were liver function tests, kidney function tests, HCV viremia, fasting glucose levels, and glycosylated hemoglobin.

RESULTS

Patients with impaired glucose metabolism were predominantly male and of older age compared to patients with normal glucose tolerance, and also had higher levels of transaminases. Proteinuria and higher creatinine levels were found in patients with impaired glucose metabolism. Overall, we found a 98.01% rate of sustained virologic response (SVR), with a non-significant difference between patients with normal and abnormal glucose metabolism. A statistically significant difference in SVR rates in patients with low degrees of fibrosis (F0-F2) versus those with advanced degrees of fibrosis (F3-F4) was found in both groups. Antiviral treatment resulted in significant decreases in fasting glucose levels and glycosylated hemoglobin levels in all patients with impaired glucose metabolism at SVR.

CONCLUSION

Patients with pre-diabetes, as well as diabetic patients, achieved a better glycemic control after SVR obtained by ritonavir-boosted paritaprevir/ombitasvir and dasabuvir.

Hepatitis C virus infection and diabetes: A complex bidirectional relationship

Chronic hepatitis C (CHC) and diabetes represent two severe chronic conditions responsible for a considerable number of deaths worldwide. They have a complex, bidirectional relationship. On the one hand, several cohort studies have shown that chronic HCV infection increases both the risk of developing diabetes in non-diabetic subjects (by inducing insulin resistance and promoting β-cell dysfunction) as well as the risk of developing macro and microvascular complications in patients with known diabetes; on the other hand, diabetes is an independent risk factor for liver-related events among patients with CHC, including a higher incidence of hepatocellular carcinoma, liver-related death and transplantation. Importantly, sustained virological response, which can be obtained in the vast majority of patients with the use of direct antiviral agents, does not only lead to a lower rate of liver-related outcomes, but also to improvements of glycemic control and reduction in the rate of complications among patients with diabetes. The aim of this review is to summarize available clinical evidence on the association among CHC, diabetes and related clinical outcomes. We will also briefly discuss the biological mechanisms underpinning the association between CHC and diabetes, as well as the implications this relationship should have on everyday clinical practice.

Hyperglycemia and Loss of Redox Homeostasis in COVID-19 Patients

The infection with SARS-CoV-2 impairs the glucose−insulin axis and this contributes to oxidative (OS) and nitrosative (NSS) stress. Here, we evaluated changes in glucose metabolism that could promote the loss of redox homeostasis in COVID-19 patients. This was comparative cohort and analytical study that compared COVID-19 patients and healthy subjects. The study population consisted of 61 COVID-19 patients with and without comorbidities and 25 healthy subjects (HS). In all subjects the plasma glucose, insulin, 8-isoprostane, Vitamin D, H2S and 3-nitrotyrosine were determined by ELISA. The nitrites (NO2−), lipid-peroxidation (LPO), total-antioxidant-capacity (TAC), thiols, glutathione (GSH) and selenium (Se) were determined by spectrophotometry. The glucose, insulin and HOMA-IR (p < 0.001), 8-isoprostanes, 3-nitrotyrosine (p < 0.001) and LPO were increased (p = 0.02) while Vitamin D (p = 0.01), H2S, thiols, TAC, GSH and Se (p < 0.001) decreased in COVID-19 patients in comparison to HS. The SARS-CoV-2 infection resulted in alterations in the glucose−insulin axis that led to hyperglycemia, hyperinsulinemia and IR in patients with and without comorbidities. These alterations increase OS and NSS reflected in increases or decreases in some oxidative markers in plasma with major impact or fatal consequences in patients that course with metabolic syndrome. Moreover, subjects without comorbidities could have long-term alterations in the redox homeostasis after infection.

HCV Genotype Has No Influence on the Incidence of Diabetes-EpiTer Multicentre Study

HCV infection is one of the main reasons for liver cirrhosis and hepatocellular carcinoma. In recent years, one finds more and more extrahepatic manifestations of HCV infection, including its possible influence on the development of diabetes. In the presented work, one finds the frequency analysis of the incidence of diabetes among 2898 HCV infected patients treated in Poland, and the assessment of their relevance to the HCV genotype and the progression of fibrosis. The results indicate that the hepatitis C infection seems to be a risk factor for diabetes in persons with more advanced liver fibrosis, for older people, and for the male gender. Thus, one found no differences regarding the frequency of its incidence depending on HCV genotype, including genotype 3.

Impact of sustained virological response on metabolic disorders in diabetic chronic hepatitis C virus patients after treatment with generic sofosbuvir and daclatasvir

OBJECTIVES

To evaluate the effect of generic sofosbuvir and daclatasvir (SOF/DCV) treatment on the glycemic state and insulin resistance as well as lipid profiles of those who achieved sustained virological response (SVR) in diabetic chronic hepatitis C virus (CHC) patients.

METHODS

We retrospectively reviewed 114 CHC patients with evidence of type 2 diabetes that were treated with generic SOF/DCV between May 2016 and August 2017. Baseline demographic and laboratory data were recorded. At 12-week post end of therapy (SVR12), glycemic state and insulin resistance as well as lipid profiles were re-evaluated and compared with baseline.

RESULTS

A total of 98 diabetic CHC patients were finally included and were responders. A significant decline in the glycemic state as well as Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) values (P ≤ 0.0001) was observed, but HOMA-S showed a statistically significant increase (P ≤ 0.0001) at SVR12 in comparison to baseline values. Also, a significant increase in serum total cholesterol, low-density lipoprotein (LDL)-cholesterol, and high-density lipoprotein (HDL)-cholesterol levels was observed at SVR12 compared to baseline, but serum triglycerides levels showed a significant decrease. Logistic regression showed that the higher baseline HOMA-IR was a significant predictive variable of a decrease ≥20% of HOMA-IR, while higher baseline HOMA-IR and baseline triglycerides emerged as the only significant predictors of the Δ increase LDL-C level at SVR12.

CONCLUSION

SOF/DCV-based therapy led to an improvement of glycemic state associated with a global worsening of lipid profile. Further studies are strongly warranted to evaluate the cardiovascular balance between amelioration of insulin resistance and negative changes of the lipid profile.

Cytokeratin 18 can help predict liver fibrosis in HCV infected patients with type 2 diabetes mellitus

BACKGROUND

To investigate the predictive values of cytokeratin 18 for liver fibrosis in hepatitis C virus (HCV) infected patients with type 2 diabetes mellitus (T2DM).

METHODS

252 HCV-infected patients with T2DM between January 2012 and August 2017 were retrospectively reviewed. Pearson/spearman correlation analysis was used to detect the correlation in the entire cohort. Multivariate linear regression was used to identify independent predictors and logistic regression was for establishing models. Combination models that incorporated CK18 and other methods (i.e. transient elastography, aspartate transaminase-to-platelet ratio index (APRI) and fibrosis-4 index (FIB-4)] were developed in a training cohort of 132 patients. Performance of models was evaluated through discrimination ability and clinical benefits. An internal validation was conducted in 120 consecutive patients.

RESULTS

CK18 was found significantly associated with fibrosis scores (r = 0.452, P < .001). CK18 and albumin were confirmed as independent predictors for fibrosis. For predicting significant fibrosis in the validation cohort, the observed AUC values of APRI + CK18 (AUC 0.83) and FIB-4 + CK18 (AUC 0.84) were higher than those of APRI (AUC 0.61) and FIB-4 (AUC 0.65). For predicting advanced fibrosis and cirrhosis, the AUC values of FIB-4 + CK18 (AUC 0.74 and 0.77, respectively) were significantly higher than those of FIB-4 (AUC 0.61 of both). Decision curve analysis confirmed the more clinical benefits can be provided by being combined with CK18.

CONCLUSIONS

CK18 is an independent predictor of liver fibrosis for HCV-infected patients with T2DM. Noninvasive methods incorporate CK18 and other biomarker indices can have better performance for diagnosing fibrosis and help clinical decision-making.

The association between hepatitis C virus infection and renal function

BACKGROUND

The association between hepatitis C virus (HCV) infection and chronic kidney disease (CKD) still remains controversial. We aimed to investigate whether HCV really affects renal function, and to analyze the association between clinical effects of CHC and decreased kidney function (assessed by glomerular filtration rate (eGFR) level).

METHODS

An estimated 3360 patients with HCV infection and 3360 age- and sex-matched community-based control individuals without HCV were enrolled (1:1, case and control ratio) in this study between 2004 and 2016. We used the modification of diet in renal diseases to calculate eGFR. Demographic and laboratory parameters were assessed, and appropriate statistical methods were performed for the analysis.

RESULTS

Multivariate logistic regression analysis revealed that serum alanine aminotransferase level (odds ratio [OR] 0.998; 95% confidence interval [CI] 0.997-0.999; P = 0.001), platelet count (OR 0.997; 95% CI 0.995-0.999; p = 0.002), and hypertension (OR 1.31; 95% CI 1.03-1.66; P = 0.027) were significantly associated with HCV infection and serum triglyceride levels (OR 1.001; 95% CI 1.00-1.002; p = 0.005), platelet count (OR 0.996; 95% CI 0.995-0.997; p < 0.001), body mass index (BMI) >25 (OR 1.43; 95% CI 1.23-1.67; p < 0.001), hypertension (OR 1.69; 95% CI 1.42-1.99; p < 0.001), hyperlipidemia (OR 1.32; 95% CI 1.02-1.71; p = 0.035), and diabetes (OR 1.33; 95% CI 1.03-1.71; p = 0.032) were significantly associated with a low eGFR (<90 mL/min/m3) in control subjects. The BMI >25 kg/m2, hypertension, and diabetes were found to be associated with low eGFR interaction with the HCV infection, via a multivariate analysis.

CONCLUSION

Our study found that the patients with HCV infection are associated with a low eGFR compared with non-HCV-infected patients. This association is consistent in obese, diabetic, and hypertensive patients.

Metabolic complications of hepatitis C virus infection

Hepatitis C virus (HCV) infection is a systemic disease that is implicated in multiple extrahepatic organ dysfunction contributing to its protean manifestations. HCV is associated with diverse extrahepatic disorders including atherosclerosis, glucose and lipid metabolic disturbances, alterations in the iron metabolic pathways, and lymphoproliferative diseases over and above the traditional liver manifestations of cirrhosis and hepatocellular carcinoma. The orchestration between HCV major proteins and the liver-muscle-adipose axis, poses a major burden on the global health of human body organs, if not adequately addressed. The close and inseparable associations between chronic HCV infection, metabolic disease, and cardiovascular disorders are specifically important considering the increasing prevalence of obesity and metabolic syndrome, and their economic burden to patients, the healthcare systems, and society. Cellular and molecular mechanisms governing the interplay of these organs and tissues in health and disease are therefore of significant interest. The coexistence of metabolic disorders and chronic hepatitis C infection also enhances the progression to liver fibrosis and hepatocellular carcinoma. The presence of metabolic disorders is believed to influence the chronicity and virulence of HCV leading to liver disease progression. This comprehensive review highlights current knowledge on the metabolic manifestations of hepatitis C and the potential pathways in which these metabolic changes can influence the natural history of the disease.

Liraglutide Inhibits Hepatitis C Virus Replication Through an AMP Activated Protein Kinase Dependent Mechanism

Insulin resistance and diabetes are both associated with chronic hepatitis C virus (HCV) infection, and the glucagon-like peptide-1(GLP-1) receptor agonist, liraglutide, is a common therapy for diabetes. Our aim was to investigate whether liraglutide treatment can inhibit HCV replication. A cell culture-produced HCV infectious system was generated by transfection of in vitro-transcribed genomic JFH-1 ribonucleic acid (RNA) into Huh-7.5 cells. Total RNA samples were extracted to determine the efficiency of HCV replication. The Ava5 cells were treated with liraglutide and cell viability was calculated. A Western blot analysis of the protein expression was performed. The immunoreactive blot signals were also detected. Liraglutide activated GLP-1 receptors in the HCV infectious system, and inhibited subgenomic HCV RNA replication in the HuH-7.5 cells. The Western blot analysis revealed both HCV protein and replicon RNA were reduced after treatment with liraglutide in a dose-dependent manner. Liraglutide decreased the cell viability of HCV RNA at an optimum concentration of 120 μg/mL, activated the 5′ adenosine monophosphate-activated protein kinase (AMPK) and the phosphorylated- transducer of regulated cyclic adenosine monophosphate (CAMP) response element-binding protein 2 (TORC2), thereby decreasing the cell viability of phosphoenolpyruvate carboxykinase (PEPCK) and G6pase RNA Therefore, we conclude that liraglutide can inhibit HCV replication via an AMPK/TORC2-dependent pathway.

Therapeutic Mechanisms of Herbal Medicines Against Insulin Resistance: A Review

Insulin resistance is a condition in which insulin sensitivity is reduced and the insulin signaling pathway is impaired. Although often expressed as an increase in insulin concentration, the disease is characterized by a decrease in insulin action. This increased workload of the pancreas and the consequent decompensation are not only the main mechanisms for the development of type 2 diabetes (T2D), but also exacerbate the damage of metabolic diseases, including obesity, nonalcoholic fatty liver disease, polycystic ovary syndrome, metabolic syndrome, and others. Many clinical trials have suggested the potential role of herbs in the treatment of insulin resistance, although most of the clinical trials included in this review have certain flaws and bias risks in their methodological design, including the generation of randomization, the concealment of allocation, blinding, and inadequate reporting of sample size estimates. These studies involve not only the single-flavored herbs, but also herbal formulas, extracts, and active ingredients. Numerous of in vitro and in vivo studies have pointed out that the role of herbal medicine in improving insulin resistance is related to interventions in various aspects of the insulin signaling pathway. The targets involved in these studies include insulin receptor substrate, phosphatidylinositol 3-kinase, glucose transporter, AMP-activated protein kinase, glycogen synthase kinase 3, mitogen-activated protein kinases, c-Jun-N-terminal kinase, nuclear factor-kappaB, protein tyrosine phosphatase 1B, nuclear factor-E2-related factor 2, and peroxisome proliferator-activated receptors. Improved insulin sensitivity upon treatment with herbal medicine provides considerable prospects for treating insulin resistance. This article reviews studies of the target mechanisms of herbal treatments for insulin resistance.

The association of hepatitis c virus infection status with serum glucose levels

Background

Hepatitis C virus (HCV) infection is commonly associated with a disturbance of glucose metabolism. However, there have been conflicting reports on whether the clearance of the HCV may be followed by changes of serum blood glucose and insulin resistance. The aim of the present study was to evaluate the impact of HCV and antiviral treatment on serum glucose levels and other glucose metabolism parameters.

Methods

A retrospective analysis of 306 HCV-infected patients was performed. Fasting serum blood glucose (FBG) levels in these patients were compared with that of 325 healthy individuals. Serum parameters of glucose metabolism were measured in 183 patients with chronic hepatitis C at baseline, at the end of interferon α-2b plus ribavirin treatment, and at 24 weeks post-treatment.

Results

Patients with HCV infection had significantly higher FBG level than healthy controls (5.57 ± 0.74 vs. 5.11 ± 0.83 mmol/l, P < 0.001). After antiviral treatment, we found a significant reduction in FBG levels regardless of the outcome of treatment. However, after stopping treatment the serum FBG levels were significantly elevated in the sustained virological response (SVR) and non-responder groups, and maintained high level until week 24 post-treatment. In both groups, the levels of serum FBG after 24 weeks post-treatment were still lower than pre-treatment levels. In sustained responders, fasting insulin (P = 0.007), C-peptide (P < 0.001) and HOMA-IR (P < 0.001) significantly decreased, and the insulin sensitivity index (ISI) increased (P < 0.001) at the end of the treatment comparing with pre-treatment levels, while no significant difference was observed in non-responder group. HOMA-β values were increased in both groups at the end of treatment (both P < 0.001).

Conclusion

The total serum FBG level in HCV infected patients was higher than that in healthy controls. Clearance of HCV was associated with reduced glucose and improved insulin resistance.

Pretransplant metabolic syndrome and its components predict post-transplantation diabetes mellitus in Chinese patients receiving a first renal transplant

Background

Post-transplantation diabetes mellitus (PTDM) remains a major clinical challenge following renal transplant. Identification of pretransplant modifiable risk factors may allow timely interventions to prevent PTDM. This study aims to determine whether pretransplant metabolic syndrome and its components are able to predict PTDM in Chinese patients receiving their first renal transplant.

Patients and methods

We conducted a single-center retrospective study of 633 non-diabetic patients receiving a first kidney transplant. PTDM was diagnosed between 1 month and 1 year post-transplant. Multivariable logistic regression and Cox proportional hazards model were applied to detect potential pretransplant risk factors for PTDM.

Results

One year post-transplant, 26.2% of recipients had developed PTDM. PTDM patients had significantly higher fasting plasma glucose (FPG) (P=0.026) and body mass index (BMI) (P=0.006) than non-PRDM patients, and lower levels of high-density lipoprotein cholesterol (P=0.015). The presence of metabolic syndrome was an independent risk factor for PTDM, as assessed by multivariable logistic regression analysis (OR 1.28, 95% CI 1.04–1.51, P=0.038) and Cox proportional hazards model (OR 2.75, 95% CI 1.45–6.05, P=0.021). Moreover, both FPG >5.6 mmol/L and BMI >28 kg/m² (obesity) were able to predict PTDM.

Conclusion

Our results suggest that the presence of metabolic syndrome and its components, impaired fasting glycemia and obesity, are independent risk factors for PTDM in Chinese non-diabetic patients receiving a first renal transplant. Interventions aimed at improving pretransplant metabolic syndrome may reduce the incidence of PTDM.

Improvement of insulin sensitivity in diabetic and non diabetic patients with chronic hepatitis C treated with direct antiviral agents

Background

The increased incidence of type 2 diabetes mellitus among hepatitis C virus (HCV) infected patients is likely due to viral-induced insulin resistance (IR). Indeed, control of diabetes in these patients benefits of successful antiviral treatment; whether the same applies to subtler alterations of glucose metabolism is unknown. We aimed to fill this gap.

Methods

The study population included 82 HCV-RNA positive patients (48 males, median age 66 years, 73 with advanced fibrosis, 41 HCV-1b), attending the liver clinic of an academic hospital to receive direct antivirals. None was previously known to be diabetic. All underwent a standard oral glucose tolerance test (OGTT) before antiviral treatment and right after its conclusion.

Results

At baseline, the majority of patients had evidence of abnormal glucose metabolism (N. = 45, 55%; impaired fasting glucose 10%, impaired glucose tolerance16%, both the above 12%, 17% diabetes), while only 37 (45%) were normally glucose tolerant (NGT). At the end of treatment, HCV-RNA quantification was below the detection threshold (HCV-RNA <12 UI/ml), for all patients enrolled. A significant decrease in glucose and insulin plasma concentrations was observed, leading to a significant reduction in Homeostasis Model Assessment (HOMA)-IR (from 3.42 [2.66–5.38] to 2.80 [1.78–3.95];p<0.001) and a corresponding increase in insulin sensitivity (ISI Belfiore from 0.49 [0.26–0.75] to 0.64 [0.42–0.91];p<0.001), despite a significant reduction in insulin secretion (EFP Stumvoll from 1363 [959–1730] to 1264 [976–1588];p = 0.027). Importantly, HOMA-IR reduction occurred also in the subgroup of NGT patients (p = 0.017). The number of NGT patients increased to 53, 65% (p = 0.013) paralleled by a reduced number of those satisfying criteria for prediabetic conditions (31 (38%) vs. 17 (21%); p = 0.025).

Conclusions

Glucose metabolism parameters of HCV infected patients improve early after antiviral treatment, with benefits that are not limited to diabetics. These findings confirm how deep and widespread is the impairment of insulin pathways exerted by HCV infection.

Molecular Mechanisms of Hepatocarcinogenesis Following Sustained Virological Response in Patients with Chronic Hepatitis C Virus Infection

Despite the success of direct-acting antiviral (DAA) agents in treating chronic hepatitis C virus (HCV) infection, the number of cases of HCV-related hepatocellular carcinoma (HCC) is expected to increase over the next five years. HCC develops over the span of decades and is closely associated with fibrosis stage. HCV both directly and indirectly establishes a pro-inflammatory environment favorable for viral replication. Repeated cycles of cell death and regeneration lead to genomic instability and loss of cell cycle control. DAA therapy offers >90% sustained virological response (SVR) rates with fewer side effects and restrictions than interferon. While elimination of HCV helps to restore liver function and reverse mild fibrosis, post-SVR patients remain at elevated risk of HCC. A series of studies reporting higher than expected rates of HCC development among DAA-treated patients ignited debate over whether use of DAAs elevates HCC risk compared to interferon. However, recent prospective and retrospective studies based on larger patient cohorts have found no significant difference in risk between DAA and interferon therapy once other factors are taken into account. Although many mechanisms and pathways involved in hepatocarcinogenesis have been elucidated, our understanding of drivers specific to post-SVR hepatocarcinogenesis is still limited, and lack of suitable in vivo and in vitro experimental systems has hampered efforts to examine etiology-specific mechanisms that might serve to answer this question more thoroughly. Further research is needed to identify risk factors and biomarkers for post-SVR HCC and to develop targeted therapies based on more complete understanding of the molecules and pathways implicated in hepatocarcinogenesis.

[Chronic HCV infection: An internist's opinion (Part 2)]

Hepatitis C virus (HCV) infection results in not only chronic hepatitis and subsequent complications as liver cirrhosis and hepatocellular carcinoma, but also in a significant number of other diseases, the so-called extrahepatic manifestations of chronic HCV infection. In addition to lymphoproliferative and autoimmune disorders discussed in Part 1 of this review, many other diseases turned to be associated with chronic HCV infection. Part 2 of this review is dedicated to the analysis of the relationship of chronic HCV-infection to the development of some endocrine diseases, such as thyroiditis and diabetes mellitus, and cardiovascular disorders. It also provides the characteristics of the currently available antiviral agents and considers whether they may be used in patents with extrahepatic manifestations of chronic HCV infection.

Study on the relationship between insulin growth factor 1 and liver fibrosis in patients with chronic hepatitis C with type 2 diabetes mellitus

OBJECTIVE

To investigate the correlation between serum protein level of insulin growth factor 1 (IGF-1) and the degree of liver fibrosis in patients with chronic hepatitis C (CHC) combined with type 2 diabetes mellitus (T2DM).

METHODS

The cases are divided into four groups. Then serum levels of IFG-1, alanine aminotransferase (ALT), aspartate aminotransferase (AST), hepatitis C virus (HCV) RNA, and HCV genotypes were detected simultaneously in patients with hepatitis C, liver stiffness measurement (LSM) was measured by transient elastography, and aspartate aminotransferase platelet ratio (APRI) score was determined.

RESULTS

There was no significant difference between CHC with T2DM group and CHC group in diabetes family history (P > 0.05), but the difference between the two groups were significantly lower than that of T2DM group ( P < 0.05). The levels of fasting insulin and homeostatic model assessment of insulin resistance (HOMA-IR) in CHC group with T2DM group were significantly higher than those in the other two groups ( P < 0.05), while the IGF-1 RNA and the serum protein level in the two groups were significantly lower than those in the CHC group, and were lower than those in the control group ( P < 0.05). The level of serum IGF-1 was negatively correlated with HOMA-IR, LSM, and APRI score in CHC with T2DM group ( r = -0.71, -0.75, and -0.69; P < 0.01).

CONCLUSION

The degree of hepatic fibrosis in patients with CHC combined with T2DM was higher than that in non-T2DM patients with CHC, which was mainly related to insulin resistance (IR) induced by 1b genotype HCV infection. IR can lead to impaired synthesis of IGF-1, and the degree of damage has a corresponding relationship with hepatic fibrosis.

Hepatitis C Virus Eradication with New Interferon-Free Treatment Improves Metabolic Profile in Hepatitis C Virus-Related Liver Transplant Recipients

Interferon (IFN)-free, direct-acting antiviral (DAA) therapy agents provide a safe and efficacious treatment for liver transplant recipients with recurrent hepatitis C virus (HCV) infection. The aim of this study is to evaluate the impact of HCV eradication on the metabolic factors in liver transplant recipients. We completed a retrospective single-center study on HCV-related liver transplant recipients treated with IFN-free DAAs including both treatment-naive and treatment-experienced patients. IFN-free DAAs impact on the metabolic profile were assessed at baseline and sustained virological response (SVR) between 24 and 48 weeks. In total, 91 liver transplant recipients with recurrent HCV infection received IFN-free DAA treatment, 62 patients had IFN-based treatment failure, and 29 were treatment-naïve, of whom 87 (96%) achieved SVR. Eradication of recurrent HCV infection was associated with reduction in the treatment of diabetes and hypertension by 38% and 22% from the baseline respectively. Hemoglobin A1c (HbA1c) levels declined from mean 35.5 ± 4.3 mmol/mol to 33.3 ±3.6 mmol/mol at 44 weeks posttreatment (P = 0.03). Total cholesterol levels increased from 3.8 ± 0.9 mmol/L to 4.9 ± 0.9 mmol/L at 41 weeks posttreatment (P < 0.0001), reflecting a significant increase in serum low-density lipoprotein (LDL) levels (2.0 ± 0.8 to 2.9 ± 0.8; P < 0.0001). Estimated glomerular filtration rate (eGFR) levels increased from 64.9 ± 20 mL/minute to 69.6 ± 20 mL/minute at 24 weeks posttreatment (P = 0.0004). Glucose, lipid profile, and eGFR changes were independent of weight changes and immunosuppression dosage and trough levels. In conclusion, eradication of recurrent HCV infection by DAA therapy has beneficial impacts on glucose metabolism and renal profile and reverses the hypolipidemic effect of HCV in liver transplant recipients. These extrahepatic effects of DAA therapy need to be validated by larger prospective studies.

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.

Hepatitis C Virus Infection in the Older Patient

Hepatitis C virus (HCV) is the most common blood-borne infection in the United States and is of concern in older adults. HCV infection is associated with not only hepatic but also extrahepatic comorbidities common to the aging patient including diabetes, kidney and cardiovascular diseases, and neurocognitive impairment. The effect of direct-acting antiviral agents to treat HCV on these outcomes is limited. This article summarizes the literature regarding the epidemiology and natural history of HCV infection; the impact of age on clinical outcomes in HCV-infected persons; and current knowledge regarding safety and efficacy of HCV treatment regimens in the older patient.

Post-Liver Transplantation Diabetes Mellitus: A Review of Relevance and Approach to Treatment

Post-liver transplantation diabetes mellitus (PLTDM) develops in up to 30% of liver transplant recipients and is associated with increased risk of mortality and multiple morbid outcomes. PLTDM is a multicausal disorder, but the main risk factor is the use of immunosuppressive agents of the calcineurin inhibitor (CNI) family (tacrolimus and cyclosporine). Additional factors, such as pre-transplant overweight, nonalcoholic steatohepatitis and hepatitis C virus infection, may further increase risk of developing PLTDM. A diagnosis of PLTDM should be established only after doses of CNI and steroids are stable and the post-operative stress has been overcome. The predominant defect induced by CNI is insulin secretory dysfunction. Plasma glucose control must start immediately after the transplant procedure in order to improve long-term results for both patient and transplant. Among the better known antidiabetics, metformin and DPP-4 inhibitors have a particularly benign profile in the PLTDM context and are the preferred oral agents for long-term management. Insulin therapy is also an effective approach that addresses the prevailing pathophysiological defect of the disorder. There is still insufficient evidence about the impact of newer families of antidiabetics (GLP-1 agonists, SGLT-2 inhibitors) on PLTDM. In this review, we summarize current knowledge on the epidemiology, pathogenesis, course of disease and medical management of PLTDM.

Regulation of insulin resistance and type II diabetes by hepatitis C virus infection: A driver function of circulating miRNAs

Hepatitis C virus (HCV) infection is a serious worldwide healthcare issue. Its association with various liver diseases including hepatocellular carcinoma (HCC) is well studied. However, the study on the relationship between HCV infection and the development of insulin resistance and diabetes is very limited. Current research has already elucidated some underlying mechanisms, especially on the regulation of metabolism and insulin signalling by viral proteins. More studies have emerged recently on the correlation between HCV infection‐derived miRNAs and diabetes and insulin resistance. However, no studies have been carried out to directly address if these miRNAs, especially circulating miRNAs, have causal effects on the development of insulin resistance and diabetes. Here, we proposed a new perspective that circulating miRNAs can perform regulatory functions to modulate gene expression in peripheral tissues leading to insulin resistance and diabetes, rather than just a passive factor associated with these pathological processes. The detailed rationales were elaborated through comprehensive literature review and bioinformatic analyses. miR‐122 was identified to be one of the most potential circulating miRNAs to cause insulin resistance. This result along with the idea about the driver function of circulating miRNAs will promote further investigations that eventually lead to the development of novel strategies to treat HCV infection‐associated extrahepatic comorbidities.

Expert opinion on managing chronic HCV infection in patients with type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) has been identified as an extrahepatic manifestation of chronic HCV infection. Conversely, in the context of chronic HCV infection, T2DM can accelerate the course of HCV-induced liver disease leading to increased risk of fibrosis, cirrhosis and hepatocellular carcinoma. The presence of T2DM negatively impacts the efficacy of interferon-based antiviral therapy, but real-world data with high-efficacy direct-acting antiviral therapies suggest high viral clearance rates in T2DM patients. In HCV-infected individuals, viral eradication is associated with a reduced risk of de novo T2DM in non-diabetic patients and beneficial metabolic changes in patients with T2DM, highlighting the importance of antiviral treatment and physician awareness of this association.

Molecular basis of hepatocellular carcinoma induced by hepatitis C virus infection

Present study outlines a comprehensive view of published information about the underlying mechanisms operational for progression of chronic hepatitis C virus (HCV) infection to development of hepatocellular carcinoma (HCC). These reports are based on the results of animal experiments and human based studies. Although, the exact delineated mechanism is not yet established, there are evidences available to emphasize the involvement of HCV induced chronic inflammation, oxidative stress, insulin resistance, endoplasmic reticulum stress, hepato steatosis and liver fibrosis in the progression of HCV chronic disease to HCC. Persistent infection with replicating HCV not only initiates several liver alterations but also creates an environment for development of liver cancer. Various studies have reported that HCV acts both directly as well as indirectly in promoting this process. Whereas HCV related proteins, like HCV core, E1, E2, NS3 and NS5A, modulate signal pathways dysregulating cell cycle and cell metabolism, the chronic infection produces similar changes in an indirect way. HCV is an RNA virus and does not integrate with host genome and therefore, HCV induced hepatocarcinogenesis pursues a totally different mechanism causing imbalance between suppressors and proto-oncogenes and genomic integrity. However, the exact mechanism of HCC inducement still needs a full understanding of various steps involved in this process.

Chicory inulin ameliorates type 2 diabetes mellitus and suppresses JNK and MAPK pathways in vivo and in vitro

SCOPE

Chicory inulin is a naturally occurring fructan that is conducive to glucose and lipid metabolism in patients with diabetes mellitus. This study aims to investigate the mechanism by which chicory inulin improves glucolipid metabolism in diabetic conditions.

METHODS AND RESULTS

Rats were injected with streptozotocin and fed with high fat diet to induce diabetes, and then administrated with different doses of chicory inulin for 8 weeks. The glycometabolism and lipid metabolism parameters were determined, the activity of insulin receptor substrate (IRS) and mitogen-activated protein kinase (MAPK) pathways were examined by western blot. The effect of chicory inulin on glucose uptake of myoblast and hepatocyte were also measured in vitro. Data were analyzed by student's t-test or one-way analysis of variance followed by the Bonferroni post-hoc testing. The results showed that chicory inulin improved glucolipid metabolism, and it activated IRS but suppressed the MAPK pathways in vivo and in vitro.

CONCLUSION

Our study demonstrates that chicory inulin, as a nutritional supplement, may be beneficial for the patients with type 2 diabetes mellitus, and the metabolism-modulatory effect seems to be related with the inhibition of JNK and P38 MAPK pathways.

Hepatitis C virus induces a prediabetic state by directly impairing hepatic glucose metabolism in mice

Virus-related type 2 diabetes is commonly observed in individuals infected with the hepatitis C virus (HCV); however, the underlying molecular mechanisms remain unknown. Our aim was to unravel these mechanisms using FL-N/35 transgenic mice expressing the full HCV ORF. We observed that these mice displayed glucose intolerance and insulin resistance. We also found that Glut-2 membrane expression was reduced in FL-N/35 mice and that hepatocyte glucose uptake was perturbed, partly accounting for the HCV-induced glucose intolerance in these mice. Early steps of the hepatic insulin signaling pathway, from IRS2 to PDK1 phosphorylation, were constitutively impaired in FL-N/35 primary hepatocytes via deregulation of TNFα/SOCS3. Higher hepatic glucose production was observed in the HCV mice, despite higher fasting insulinemia, concomitant with decreased expression of hepatic gluconeogenic genes. Akt kinase activity was higher in HCV mice than in WT mice, but Akt-dependent phosphorylation of the forkhead transcription factor FoxO1 at serine 256, which triggers its nuclear exclusion, was lower in HCV mouse livers. These findings indicate an uncoupling of the canonical Akt/FoxO1 pathway in HCV protein-expressing hepatocytes. Thus, the expression of HCV proteins in the liver is sufficient to induce insulin resistance by impairing insulin signaling and glucose uptake. In conclusion, we observed a complete set of events leading to a prediabetic state in HCV-transgenic mice, providing a valuable mechanistic explanation for HCV-induced diabetes in humans.

Current level of evidence on causal association between hepatitis C virus and type 2 diabetes: A review

The association between hepatitis C virus (HCV) infection and type 2 diabetes (T2D) has been known for over 20 years. Cross-sectional and longitudinal studies have shown a higher prevalence and incidence, respectively, of T2D in patients with chronic HCV infection. HCV induces glucose metabolism alterations mostly interfering with the insulin signaling chain in hepatocytes, although extrahepatic mechanisms seem to contribute. Both IR and T2D accelerate the histological and clinical progression of chronic hepatitis C as well as the risk of extra-hepatic complications such as nephropathy, acute coronary events and ischemic stroke. Before the availability of direct-acting antivirals (DAAs), the therapeutic choice was limited to interferon (IFN)-based therapy, which reduced the incidence of the extra-hepatic manifestations but was burdened with several contraindications and poor tolerability. A better understanding of HCV-associated glucose metabolism derangements and their reversibility is expected with the use of DAAs.

Impact of hepatitis C virus therapy on metabolism and public health

Chronic hepatitis C virus (HCV) is associated with insulin resistance (IR) and leads to type 2 diabetes mellitus (T2DM) and hepatic steatosis in many patients. These metabolic complications of HCV have been shown to accelerate the progression of fibrosis to cirrhosis and increase the risk of hepatocellular carcinoma. The metabolic syndrome is a common disorder that also includes IR, T2DM and hepatic steatosis. Approximately 20%-30% of patients with chronic HCV also have co-existent metabolic syndrome. The cause of steatosis in patients with the features of both the metabolic syndrome and chronic HCV is sometime difficult to determine. Patients with metabolic syndrome and chronic HCV are also at risk of developing renal, cardiovascular and cerebrovascular disease. Recent data suggest that HCV is an independent risk factor for renal, coronary and cerebral vascular disease, and may increase mortality associated with these disorders. The treatment of HCV can now result in a sustained virological response and cure nearly all patients with chronic HCV. The eradication of HCV reduces the risk of developing IR and T2DM, improves IR and 2TDM, reduces the risk of developing chronic kidney disease, end-stage renal disease, acute cardiac syndrome and stroke in patients with 2TDM. Thus, treatment of chronic HCV can provide a significant public health benefit, but only if all patients with chronic HCV are identified and universally treated.

Sequential cleavage of insulin receptor by calpain 2 and γ-secretase impairs insulin signalling

AIMS/HYPOTHESIS

Soluble insulin receptor (sIR), the ectodomain of the insulin receptor (IR), has been detected in human plasma and its concentration paralleled that of blood glucose. We have previously developed an in vitro model using HepG2 liver-derived cells, which mimics changes in sIR levels in plasma from diabetic patients and shows that calcium-dependent proteases cleave IR extracellularly (a process known as shedding). The present study aimed to reveal the mechanisms of IR cleavage.

METHODS

Using the in vitro model, we investigated the molecular mechanisms of IR cleavage, which is accelerated by high-glucose treatment. We also analysed the relationship between IR cleavage and cellular insulin resistance, and the correlation between plasma sIR levels and insulin sensitivity, which was assessed by the euglycaemic-hyperinsulinaemic clamp technique.

RESULTS

Here, we determined that calpain 2, which is secreted into the extracellular space associated with exosomes, directly cleaved the ectodomain of the IRβ subunit (IRβ), which in turn promoted intramembrane cleavage of IRβ by γ-secretase. IR cleavage impaired insulin signalling and the inhibition of IR cleavage (by knockdown of calpain 2 and γ-secretase), restored IR substrate-1 and Akt, independent of IR. Furthermore, the glucose-lowering drug, metformin, prevented IR cleavage accompanied by inhibition of calpain 2 release in exosomes, and re-established insulin signalling. In patients with type 2 diabetes, plasma sIR levels inversely correlated with insulin sensitivity.

CONCLUSIONS/INTERPRETATION

Sequential cleavage of IR by calpain 2 and γ-secretase may contribute to insulin signalling in cells and its inhibition may be partly responsible for the glucose-lowering effects of metformin. Thus, IR cleavage may offer a new mechanism for the aetiology of insulin resistance.

Application of network construction to estimate functional changes to insulin receptor substrates 1 and 2 in Huh7 cells following infection with the hepatitis C virus

Hepatitis C virus (HCV) is closely associated with insulin resistance (IS), acting primarily by interfering with insulin signaling pathways, increasing cytokine-mediated (tumor necrosis factor α, interleukin 6) inflammatory responses and enhancing oxidative stress. In the insulin signaling pathways, the insulin receptor substrate (IRS) is one of the key regulatory factors. The present study constructed gene regulatory sub‑networks specific for IRS1 and IRS2 in Huh7 cells and HCV‑infected Huh7 (HCV‑Huh7) cells using linear programming and a decomposition algorithm, and investigated the possible mechanisms underlying the function of IRS1/2 in HCV‑induced IS in Huh7 cells. All data were obtained from GSE20948 of the Gene Expression Omnibus database from the National Center for Biotechnology Information. Genes which were significantly differentially expressed between Huh7 and HCV‑Huh7 cells were analyzed using the significance analysis of microarray algorithm. The top 50 genes, including IRS1/2, were used as target genes to determine the gene regulatory networks and next the sub‑networks of IRS1 and IRS2 in HCV‑Huh7 and Huh7 cells using Gene Regulatory Network Inference Tool, an algorithm based on linear programming and the decomposition process. The IRS1/2 sub‑networks were divided into upstream/downstream groups and activation/suppression clusters, and were further analyzed using Molecule Annotation System 3.0 and Database for Annotation, Visualization, and Integrated Discovery software, two online platforms for enrichment and clustering analysis and visualization. The results indicated that in Huh7 cells, the downstream network of IRS2 is more complex than that of IRS1, indicating that the insulin metabolism in Huh7 cells may be primarily mediated by IRS2. In HCV‑Huh7 cells, the downstream pathway of IRS2 is blocked, suggesting that this may be the underlying mechanism in HCV infection that leads to insulin resistance. The present findings add a further dimension to the understanding of the pathological mechanisms of HCV infection-associated insulin resistance, and provide novel concepts for insulin resistance and glucose metabolism research.

Relationship between HHV8 infection markers and insulin sensitivity in ketosis-prone diabetes

BACKGROUND AND OBJECTIVES

Peripheral tissue resistance to insulin action is a characteristic of type 2 diabetes mellitus (T2DM). It has also been reported that some chronic viral infections can contribute to insulin resistance. Human herpesvirus (HHV)-8 infection has been detected in T2DM patients in previous studies. Our study investigated whether the presence of the virus is associated with insulin resistance in patients with ketosis-prone type 2 diabetes (KPD), as reported with other viruses.

RESEARCH DESIGN AND METHODS

A total of 11 insulin-free KPD patients positive (+) and seven patients who were negative (-) for HHV-8 infection were recruited; the latter had KPD that was well controlled (HbA_1c=6.2±0.7%). A two-step euglycaemic-hyperinsulinaemic clamp test coupled with deuterated [6,6-2H2]glucose was used to assess insulin sensitivity, non-esterified fatty acid (NEFA) suppression and endogenous glucose production.

RESULTS

In KPD patients, whether HHV-8+ or HHV-8-, there were no differences in NEFA release, endogenous glucose production or insulin sensitivity (M value).

CONCLUSION

Asymptomatic HHV-8 infection does not appear to be associated with decreased insulin sensitivity in diabetic patients. These results should now be confirmed in a larger sample population.

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.

Hepatitis C and insulin action: An intimate relationship

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

[Clinical Implication of Insulin Resistance in Chronic Hepatitis C Patients]

Chronic hepatitis C virus (HCV) infection is the leading cause for the development of liver cirrhosis and hepatocellular carcinoma, however, it also causes metabolic disorders. Insulin resistance is representative of these metabolic disorders, and not only leads to the development of diabetes but also affects the outcome of antiviral treatment with interferon. Historically, the standard of care for chronic HCV infection was pegylated interferon and ribavirin, but only 40-50% of HCV genotype 1 patients achieve a sustained virological response (SVR). We successfully established a pretreatment prediction model for the treatment outcome using a homeostasis model assessment of insulin resistance (HOMA-IR) and the interleukin 28B genotype (rs 8099917). In recent years, antiviral agents targeting viral proteins critical for HCV replication have become available. Of these, telaprevir, an HCV NS3/4A serine protease inhibitor, has been available in Japan since 2011. As a result, about 80% of patients with HCV genotype 1 can achieve SVR. Nonetheless, insulin resistance is associated with treatment failure, especially for difficult-to-treat patients. In the near future, almost all patients with chronic HCV infection will achieve virological clearance with combined direct antiviral agents, however, insulin resistance will remain a risk for hepatocellular carcinoma. Therefore, the prevention of obesity and avoidance of excessive alcohol intake are very important after achieving SVR.

Plasma betatrophin levels in patients with liver cirrhosis

AIM: To investigate the plasma levels of betatrophin in patients with cirrhosis.

METHODS: Forty patients diagnosed at the clinic with liver cirrhosis according to biological, ultrasonographic, or histological criteria were included. The severity of cirrhosis was classified according to Pugh’s modification of Child’s classification and MELD score. Insulin resistance (IR) was assessed by the Homeostasis Model Assessment. A total of 20 patients showed a MELD score higher than 14. The control group consisted in 15 sex-and aged-matched subjects. Fasting blood samples were obtained for subsequent analysis. Serum insulin was determined by Liaison automated immune chemiluminiscence assay (DiaSorin S.p.A.) using a sandwich assay. The sensitivity of the assay was 0.2 μU/mL. The intra and interassay variation coefficients were < 4% and < 10%, respectively. The normal values were between 2 and 17 μU/mL. Human active betatrophin was analyzed by specific quantitative sandwich ELISA (Aviscera Bioscience^®). The sensitivity of the assay was 0.4 ng/mL, and the intra and interassay reproducibility were < 6% and < 10%, respectively.

RESULTS: Plasma betatrophin levels were significantly increased in patients with cirrhosis compared with those in healthy subjects (P = 0.0001). Betatrophin levels were also associated with disease severity, being higher in Child-Pugh C patients compared to Child-Pugh B (P < 0.0005) and in patients who displayed a MELD score higher than 14 points compared to patients with lower punctuation (P = 0.01). In addition, we found a positive correlation between plasma betatrophin levels and the severity of cirrhosis according to Child-Pugh classification (r = 0.53; P < 0.01) or MELD score (r = 0.45; P < 0.01). In the overall cohort, a moderate correlation between serum betatrophin and plasmatic bilirrubin (r = 0.39; P < 0.01) has been observed, as well as an inverse correlation between betatrophin and albumin (r = -0.41; P < 0.01) or prothrombin time (r = -0.44; P <0.01). Moreover, insulin resistance was observed in 82.5% of the cirrhotic patients. In this group of patients, betatrophin levels were significantly higher than those in the group of patients without IR (P < 0.05).

CONCLUSION: Plasma betatrophin is increased in patients with cirrhosis. This increase is related to the severity of cirrhosis, as well as with the emergence of insulin resistance.

Profiling Kinase Activity during Hepatitis C Virus Replication Using a Wortmannin Probe

To complete its life cycle, the hepatitis C virus (HCV) induces changes to numerous aspects of its host cell. As kinases act as regulators of many pathways utilized by HCV, they are likely enzyme targets for virally induced inhibition or activation. Herein, we used activity-based protein profiling (ABPP), which allows for the identification of active enzymes in complex protein samples and the quantification of their activity, to identify kinases that displayed differential activity in HCV-expressing cells. We utilized an ABPP probe, wortmannin-yne, based on the kinase inhibitor wortmannin, which contains a pendant alkyne group for bioconjugation using bioorthogonal chemistry. We observed changes in the activity of kinases involved in the mitogen-activated protein kinase pathway, apoptosis pathways, and cell cycle control. These results establish changes to the active kinome, as reported by wortmannin-yne, in the proteome of human hepatoma cells actively replicating HCV. The observed changes include kinase activity that affect viral entry, replication, assembly, and secretion, implying that HCV is regulating the pathways that it uses for its life cycle through modulation of the active kinome.

Administration of Danhong Injection to diabetic db/db mice inhibits the development of diabetic retinopathy and nephropathy

Danhong Injection (DHI), a Chinese medicine for treatment of patients with coronary heart disease, inhibits primary abdominal aortic aneurysms in apoE deficient (apoE^−/−) mice. Formation of microaneurysms plays an important role in the development of diabetic retinopathy and nephropathy. It remains unknown if DHI can reduce these diabetic complications. In this study, diabetic db/db mice in two groups were injected with saline and DHI, respectively, for 14 weeks. Blood and tissue samples were collected to determine serum glucose, lipids and tissue structure. DHI reduced diabetes-induced body weight gain, serum cholesterol and glucose levels. In retinas, DHI blocked the shrink of whole retina and retinal sub-layers by inhibiting expression of caspase 3, matrix metalloproteinase 2 (MMP-2) and MMP-9, accumulation of carbohydrate macromolecules and formation of acellular capillaries. DHI improved renal functions by inhibiting mesangial matrix expansion, expression of vascular endothelial growth factor A, fibronectin and advanced glycation end products in kidneys. Mechanistically, DHI induced expression of glucokinase, AMPKα/phosphorylated AMPKα, insulin receptor substrate 1, fibroblast growth factor 21 and peroxisome proliferator-activated γ. Expression of genes responsible for energy expenditure was also activated by DHI. Therefore, DHI inhibits diabetic retinopathy and nephropathy by ameliorating glucose metabolism and demonstrates a potential application in clinics.

Insulin resistance and its consequences in chronic hepatitis C

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

To study the prevalence of impaired glucose tolerance in patients with hepatitis C virus related chronic liver disease

BACKGROUND

Hepatitis C infection is a major cause of Chronic Liver Disease and the prevalence of Diabetes Mellitus is also high. Diabetes has been hypothesised as one of Extrahepatic manifestations of Hepatitis C.

AIMS AND OBJECTIVES

The objective of our study was to study the prevalence of impaired glucose tolerance in patients with HCV related liver disease.

STUDY DESIGN

The study was a prospective study conducted over a period of one and half year in Dayanand Medical College and Hospital, Ludhiana, Punjab, India.

MATERIALS AND METHODS

The study was conducted taking total of 100 Hepatitis C virus positive patients above 40 years of age who had fasting blood glucose levels ≥110mg/dl on two occasions, 24 hours apart. These patients underwent an oral glucose tolerance test. Blood sugar levels were tested at 0 and 2 hours. Based on the findings, patients were classified to have impaired glucose tolerance if levels were between 140-200mg/dl and frank diabetes if the levels were ≥ 200mg/dl. These findings were further assessed according to age, gender, Body Mass Index (BMI) Child Turcott Pugh score and Ultrasonography findings.

STATISTICAL ANALYSIS

In our study all the statistical analysis was done using simple z-test and student t-test. The p-values were calculated and the results assessed accordingly.

RESULTS AND CONCLUSION

Out of 100 patients, 78 were males and rest females. The mean age of the study group was 55.89±11.22 years. Mean BMI of males was higher than in females (21.98kg/m² v/s 20.13kg/m²). Maximum patients belonged to Child Turcott Pugh class C. Out of 100 patients,80 had cirrhosis on ultrasound. On doing Glucose Tolerance Test, 40 patients were found to have impaired glucose tolerance and one patient to be diabetic. The prevalence increased significantly as age increased and had significant relation with gender. On assessing according to BMI, there was not much significant relation but prevalence was significantly related to severity of disease.