Hepatitis C virus infection: molecular pathways to insulin resistance

The Impact of Insulin Resistance on Hepatic Fibrosis among United States Adults with Non-Alcoholic Fatty Liver Disease: NHANES 2017 to 2018

BACKGRUOUND

We aimed to investigate the association of hepatic steatosis with liver fibrosis and to assess the interactive effects of hepatic steatosis and insulin resistance on liver fibrosis in a nationally representative sample of United States adults.

METHODS

We conducted a cross-sectional analysis using data from National Health and Nutrition Examination Survey 2017 to 2018, which for the first time included transient elastography to assess liver stiffness and hepatic steatosis. We evaluated the association between hepatic steatosis (using controlled attenuation parameter [CAP]) and clinically significant liver fibrosis (defined as liver stiffness ≥7.5 kPa) using logistic regression with an interaction term for hepatic steatosis and insulin resistance (defined as homeostatic model assessment of insulin resistance ≥3.0).

RESULTS

Among adults undergoing transient elastography (n=2,023), 45.9% had moderate or greater hepatic steatosis and 11.3% had clinically significant liver fibrosis. After adjustment for demographic and metabolic factors, the odds of significant liver fibrosis increased as CAP score rose (odds ratio, 1.35 per standard deviation increment; 95% confidence interval, 1.11 to 1.64). We detected a significant interaction effect between CAP score and insulin resistance on the probability of significant liver fibrosis (P=0.016 for interaction). The probability of significant liver fibrosis increased in the presence of insulin resistance with increasing CAP score, while those without insulin resistance had low probability of significant liver fibrosis, even with high CAP scores.

CONCLUSION

Individuals with hepatic steatosis had higher odds of fibrosis when insulin resistance was present. Our findings emphasize the importance of the metabolic aspects of the disease on fibrosis risk and suggest a need to better identify patients with metabolic associated fatty liver disease.

Clinical implications of diabetes in chronic liver disease: Diagnosis, outcomes and management, current and future perspectives

Diabetes mellitus (DM) is common in liver cirrhosis (LC). The pathophysiological association is bidirectional. DM is a risk factor of LC and LC is a diabetogenic condition. In the recent years, research on different aspects of the association DM and LC has been intensified. Nevertheless, it has been insufficient and still exist many gaps. The aims of this review are: (1) To discuss the latest understandings of the association of DM and LC in order to identify the strategies of early diagnosis; (2) To evaluate the impact of DM on outcomes of LC patients; and (3) To select the most adequate management benefiting the two conditions. Literature searches were conducted using PubMed, Ovid and Scopus engines for DM and LC, diagnosis, outcomes and management. The authors also provided insight from their own published experience. Based on the published studies, two types of DM associated with LC have emerged: Type 2 DM (T2DM) and hepatogenous diabetes (HD). High-quality evidences have determined that T2DM or HD significantly increase complications and death pre and post-liver transplantation. HD has been poorly studied and has not been recognized as a complication of LC. The management of DM in LC patients continues to be difficult and should be based on drug pharmacokinetics and the degree of liver failure. In conclusion, the clinical impact of DM in outcomes of LC patients has been the most studied item recently. Nevertheless many gaps still exist particularly in the management. These most important gaps were highlighted in order to propose future lines for research.

[Hepatitis C virus (Flaviviridae: Hepacivirus: Hepacivirus C): regulation of signaling reactions of innate immunity]

Studying the regulation of signaling reactions of innate immunity by the hepatitis C virus (HCV) will help to reveal the causes of the transition of the acute form of the disease to a chronic course. The molecular mechanisms of activation by HCV RNA of innate immunity receptors TLR and RLR and signal transduction processes leading to the synthesis of IFN and inflammatory cytokines are considered. The inhibitory effects of non-structural and structural HCV proteins on immune signaling reactions are analyzed in detail. The information presented is the result of an analysis of literature data published in international databases mainly over the past 5 years. In conclusion, signaling receptors are proposed as targets for the development of new antiviral drugs with immunotherapeutic activity.

Comparative modulation of lncRNAs in wild-type and rag1-heterozygous mutant zebrafish exposed to immune challenge with spring viraemia of carp virus (SVCV)

Although the modulation of immune-related genes after viral infection has been widely described in vertebrates, the potential implications of non-coding RNAs (ncRNAs), especially long non-coding RNAs (lncRNAs), in immunity are still a nascent research field. The model species zebrafish could serve as a useful organism for studying the functionality of lncRNAs due to the numerous advantages of this teleost, including the existence of numerous mutant lines. In this work, we conducted a whole-transcriptome analysis of wild-type (WT) and heterozygous rag1 mutant (rag1^+/-) zebrafish after infection with the pathogen spring viraemia of carp virus (SVCV). WT and rag1^+/- zebrafish were infected with SVCV for 24 h. Kidney samples were sampled from infected and uninfected fish for transcriptome sequencing. From a total of 198,540 contigs, 12,165 putative lncRNAs were identified in zebrafish. Most of the putative lncRNAs were shared by the two zebrafish lines. However, by comparing the lncRNA profiles induced after SVCV infection in WT and rag1^+/- fish, most of the lncRNAs that were significantly induced after viral challenge were exclusive to each line, reflecting a highly differential response to the virus. Analysis of the neighboring genes of lncRNAs that were exclusively modulated in WT revealed high representation of metabolism-related terms, whereas those from rag1^+/- fish showed enrichment in terms related to the adaptive immune response, among others. On the other hand, genes involved in numerous antiviral processes surrounded commonly modulated lncRNAs, as expected. These results clearly indicate that after SVCV infection in zebrafish, the expression of an array of lncRNAs with functions in different aspects of immunity is induced.

The impact of a successful treatment of hepatitis C virus on glyco-metabolic control in diabetic patients: a systematic review and meta-analysis

AIMS

The effect of HCV eradication following the use of direct-acting antiviral drugs (DAAs) on the glyco-metabolic control is unknown. Through a meta-analysis of available clinical studies, we investigated whether eradication of HCV infection with interferon-free DAAs is associated with improved glyco-metabolic control in diabetic patients.

METHODS

We searched the PubMed, MEDLINE and Embase, up to 08th June 2018, for all studies evaluating whether eradication of HCV infection with DAAs is associated with changes in glycated haemoglobin (HbA1c) and fasting plasma glucose (FPG) levels from baseline in human subjects, without restrictions for study type and language. Data were independently extracted by two researchers using pre-specified forms. Random effects meta-analyses were conducted on HbA1c and FPG levels before/after HCV eradication.

RESULTS

We found a significant mean reduction in HbA1c levels of - 0.45% (95% CI - 0.60 to - 0.30%; P < 0.001) and in FPG levels of - 22.03 mg/dL (95% CI - 41.61 to - 2.44 mg/dL; P = 0.03), with high heterogeneity between studies (χ² = 20.4, P < 0.001, I² = 80% and χ² = 35.8, P = 0.001, I² = 94%, respectively). The number of available manuscripts did not allow conducting a meta-regression to elucidate the role of sustained virological response and other confounders in determining the effect of direct-acting antiviral agents on HbA1c reduction.

CONCLUSIONS

We found a significant improvement in glyco-metabolic control after HCV eradication (in terms of glycated haemoglobin and fasting plasma glucose levels reduction) following direct-acting antiviral treatment in patients with established diabetes, including a consequent positive impact on anti-diabetic therapies.

Subclinical cardiovascular damage in patients with HCV cirrhosis before and after treatment with direct antiviral agents: a prospective study

BACKGROUND

Cirrhosis is associated with morpho-functional cardiovascular alterations.

AIMS

To detect early features of cardiovascular damage in HCV-compensated cirrhotic patients using myocardial deformation indices and carotid arterial stiffness, and, further, to evaluate their short-term behaviour after HCV eradication with direct antiviral agents (DAAs).

METHODS

Thirty-nine consecutive patients with HCV cirrhosis, without previous cardiovascular events, were studied and matched for age, gender and cardiovascular risk factors to 39 controls without liver or cardiovascular disease. Patients and controls underwent a baseline echocardiographic evaluation including global longitudinal strain and ultrasound scan of carotid arteries. HCV-cirrhotics were reassessed by echocardiography and carotid ultrasound after obtaining sustained virological response (SVR) on DAAs.

RESULTS

HCV-cirrhotics showed at baseline a significantly reduced global longitudinal strain compared to controls -18.1 (16.3-20.5) vs -21.2 (20.4-22.3), P < 0.001. They also had a significantly higher pulse wave velocity 8.6 (7.7-9.1) m/s vs 6.6 (6.0-7.1) m/s, P = 0.0001, and β-stiffness index 12.4 (11.1-13.5) vs 8.6 (8.0-9.2) P = 0.0001. At multiple regression analysis, diabetes and HCV cirrhosis were independent predictors of global longitudinal strain. All HCV-cirrhotic patients had SVR on DAAs. Follow-up available in 32 of 39 (82%) at 9 (8-10) months showed a significant improvement of tricuspid annular plane systolic excursion (P = 0.01) and lateral E' velocity compared to baseline (P = 0.001).

CONCLUSIONS

HCV-cirrhotics show a significant rate of subclinical cardiac and vascular abnormalities. At a time when their survival is less linked to progression of liver disease, due to viral eradication on DAAs, cardiovascular morbidity and mortality may take a significant role.

Effect of branched-chain amino acid supplementation on insulin resistance and quality of life in chronic hepatitis C patients

The incidence rate of insulin resistance (IR) in patients with chronic hepatitis C (CHC) is high. Recently, branched-chain amino acids (BCAA) have been shown to attenuate IR in CHC patients; however, their effect on patient quality of life remains unclear. Therefore, the aim of the current prospective study was to determine the effects of BCAA supplement on IR and health-related quality of life (HR-QoL) in patients with CHC. In the study, 20 non-diabetic patients with CHC, who were non-responders to peginterferon-α and ribavirin, were recruited. Patients took a BCAA supplement once a day (30 g, after a minimum 10-h overnight fast) for 3 months. Serum levels of glucose, insulin, albumin, triglycerides and cholesterol were measured at 0 and 3 months. Additionally, IR was measured using the Homeostasis Model Assessment-IR, HR-QoL was assessed using the 36-item Short Form Health Survey and viral load was measured by reverse transcription polymerase chain reaction using Taqman probes. The Wilcoxon signed-rank test was used to determine statistical significance. The results indicated that 70% of the subjects were positive for IR, which decreased to 50% by the end of the study; furthermore, 85% of the subjects demonstrated some level of improvement. Overall, the BCAA treatment significantly decreased IR (P=0.006) and augmented serum albumin concentration (P=0.008) compared with basal values. Additionally, by the end of the treatment, viral load and triglycerides levels had decreased, though these results were not significant (P=0.084 and P=0.080, respectively). BCAA treatment also improved HR-QoL regarding role limitations due to physical health problems (P=0.017), role limitations due to emotional problems (P=0.026) and social function (P=0.008). In conclusion, BCAA supplementation reduced IR and improved HR-QoL in patients with CHC. These findings support the application of IR therapy as a possible therapeutic strategy for hepatitis C infection.

Factors Associated with Improved Glycemic Control by Direct-Acting Antiviral Agent Treatment in Egyptian Type 2 Diabetes Mellitus Patients with Chronic Hepatitis C Genotype 4

BACKGROUND

The association of chronic hepatitis C virus (HCV) infection with type 2 diabetes mellitus (T2DM) was first reported in 1994. Little is known about the effect of direct-acting antiviral agents (DAAs) on glycemic control in T2DM patients. The aim of the present study was to evaluate the factors associated with improved glycemic control (IGC) by DAA treatment in Egyptian T2DM patients with chronic HCV genotype 4 infection.

METHODS

This study included 460 T2DM patients with chronic HCV genotype 4 infection. Four hundred patients received DAAs and 60 patients did not receive DAAs. Patients with sustained virological response after 3 months of DAAs (378 patients) were allocated into two groups: first group included 292 patients (77.2%) with IGC and second group included 86 patients (22.8%) with non-improved glycemic control (NIGC).

RESULTS

In IGC group, 78 patients (26.7%) needed to decrease the dose of antidiabetic treatment. There were no significant differences between IGC and NIGC groups as regards age, sex, and body mass index. The percentage of patients with positive family history of T2DM, those with Child B class and duration of T2DM were significantly higher in NIGC group compared to IGC.

CONCLUSION

Diabetic patients receiving DAAs should be closely monitored for reduction of antidiabetic drugs especially insulin and sulfonylurea to avoid hypoglycemic events. Improvement of glycemic control with DAAs is more in patients without family history of T2DM, short duration of diabetes mellitus, and mild liver disease.

Lack of Association between Hepatitis C Virus core Gene Variation 70/91aa and Insulin Resistance

The role of hepatitis C virus (HCV) in insulin resistance (IR) is not fully understood. The aim of this study was to determine the impact of amino acid (aa) substitutions in the core region of HCV according to IR and to identify clinical and laboratory associations. Ninety-two treatment-naive HCV patients were recruited to determine laboratory data and blood cell count. IR was determined using Homeostasis Model Assessment (HOMA) index where IR was defined as HOMA ≥2. HCV RNA load and genotype were determined by Abbott Real time HCV. HCV core region was determined by direct nucleotide sequencing. Bivariate analysis was conducted using HOMA IR ≥2 as a dependent factor. IR prevalence was 43.5% (n = 40), vitamin D sufficiency was found in 76.1% (n = 70) and 72.8% (n = 67) had advanced liver fibrosis. In the bivariate analyses, elevated values of γGT (p = 0.024) and fibrosis staging (p = 0.004) were associated with IR, but IR was not related to core mutations. The presence of glutamine in position 70 was associated with low vitamin D concentration (p = 0.005). In the multivariate analysis, no variable was independently associated with HOMA-IR. In conclusion, lack of association between IR and HCV core mutations in positions 70 and 91 suggests that genetic variability of this region has little impact on IR.

Development of experimental fibrotic liver diseases animal model by Carbon Tetracholoride

AIM

This study is presenting an effective method of inducing liver fibrosis by CCL4 as a toxin in two different breeds of rat models.

BACKGROUND

Liver fibrosis is a result of inflammation and liver injury caused by wound healing responses which ultimately lead to liver failure. Consequently, after liver fibrosis, the progression will be continued to liver cirrhosis and at the end stage hepatocellular carcinoma (HCC). Many studies have demonstrated that one of the most important causes of liver fibrosis is Non-alcoholic steatohepatitis (NASH). Fibrotic Liver is affected by an excessive accumulation of extracellular matrix (ECM) proteins like collagen and α-SMA.

METHODS

In two different experiments, male Vistar, and Sprague Dawley Rat models ranging from 200±60, corresponding to an age of approximately 10 weeks were utilized in order to induce CCL4 treated liver fibrosis.

RESULTS

After 6 weeks of CCL4 injection, different tests have been carried out to verify the liver fibrosis including serum markers such as Aspartate aminotransferase (AST) and Alanine aminotransferase (ALT), molecular tests containing, laminin and α-SMA and also pathological observation by Hematoxylin and eosin staining in both fibrosis and control group.

CONCLUSION

The results of Pathology and Real-time PCR showed that fibrosis was induced much more effectively in Sprague Dawley rat model compared with Wistar rats.

Hepatitis C virus infection induces elevation of CXCL10 in human brain microvascular endothelial cells

Hepatitis C virus (HCV) primarily infects liver tissues, while pathogenesis of extrahepatic tissues has been reported. About 50% of patients with HCV infection suffer from neurological disease. The underlying molecular mechanisms remain unclear. In the present study, we aimed to investigate the induction of CXC chemokine ligand 10 (CXCL10) in human brain microvascular endothelial cells (HBMECs) by HCV infection. CXCL10 and its receptor CXCR3 were constitutively expressed in HBMECs. HCV infection induced CXCL10 elevation in HBMECs. The elevation of CXCL10 in HBMECs was eliminated when HCV infection was blocked by neutralizing antibodies. NF-κB is a positive regulator for CXCL10 transcription. HCV infection led to an increased phosphorylation of NF-κB (ser536) in HBMECs, and CXCL10 induced by HCV was slightly decreased when an inhibitor of NF-κB was added. IL1 beta and IFN gama were also upregulated in HCV infected HBMECs, and could be depressed by inhibitor of NF-κB. Thus, HCV infection leads to upregulated expression of CXCL10 in HBMECs, which is probably via the phosphorylation of NF-κB. The findings of this study provide potential mechanisms and novel targets for HCV induced neuroinflammation. J. Med. Virol. 88:1596-1603, 2016. © 2016 Wiley Periodicals, Inc.

Hepatitis C virus NS5A promotes insulin resistance through IRS-1 serine phosphorylation and increased gluconeogenesis

AIM: To investigate the mechanisms of insulin resistance in human hepatoma cells expressing hepatitis C virus (HCV) nonstructural protein 5A (NS5A).

METHODS: The human hepatoma cell lines, Huh7 and Huh7.5, were infected with HCV or transiently-transfected with a vector expressing HCV NS5A. The effect of HCV NS5A on the status of the critical players involved in insulin signaling was analyzed using real-time quantitative polymerase chain reaction and Western blot assays. Data were analyzed using Graph Pad Prism version 5.0.

RESULTS: To investigate the effect of insulin treatment on the players involved in insulin signaling pathway, we analyzed the status of insulin receptor substrate-1 (IRS-1) phosphorylation in HCV infected cells or Huh7.5 cells transfected with an HCV NS5A expression vector. Our results indicated that there was an increased phosphorylation of IRS-1 (Ser³⁰⁷) in HCV infected or NS5A transfected Huh7.5 cells compared to their respective controls. Furthermore, an increased phosphorylation of Akt (Ser⁴⁷³) was observed in HCV infected and NS5A transfected cells compared to their mock infected cells. In contrast, we observed decreased phosphorylation of Akt Thr308 phosphorylation in HCV NS5A transfected cells. These results suggest that Huh7.5 cells either infected with HCV or ectopically expressing HCV NS5A alone have the potential to induce insulin resistance by the phosphorylation of IRS-1 at serine residue (Ser³⁰⁷) followed by decreased phosphorylation of Akt Thr³⁰⁸, Fox01 Ser²⁵⁶ and GSK3β Ser⁹, the downstream players of the insulin signaling pathway. Furthermore, increased expression of PECK and glucose-6-phosphatase, the molecules involved in gluconeogenesis, in HCV NS5A transfected cells was observed.

CONCLUSION: Taken together, our results suggest the role of HCV NS5A in the induction of insulin resistance by modulating various cellular targets involved in the insulin signaling pathway.

Trypanosoma cruzi infection is a potent risk factor for non-alcoholic steatohepatitis enhancing local and systemic inflammation associated with strong oxidative stress and metabolic disorders

BACKGROUND

The immune mechanisms underlying experimental non-alcoholic steatohepatitis (NASH), and more interestingly, the effect of T. cruzi chronic infection on the pathogenesis of this metabolic disorder are not completely understood.

METHODOLOGY/PRINCIPAL FINDINGS

We evaluated immunological parameters in male C57BL/6 wild type and TLR4 deficient mice fed with a standard, low fat diet, LFD (3% fat) as control group, or a medium fat diet, MFD (14% fat) in order to induce NASH, or mice infected intraperitoneally with 100 blood-derived trypomastigotes of Tulahuen strain and also fed with LFD (I+LFD) or MFD (I+MFD) for 24 weeks. We demonstrated that MFD by itself was able to induce NASH in WT mice and that parasitic infection induced marked metabolic changes with reduction of body weight and steatosis revealed by histological studies. The I+MFD group also improved insulin resistance, demonstrated by homeostasis model assessment of insulin resistance (HOMA-IR) analysis; although parasitic infection increased the triglycerides and cholesterol plasma levels. In addition, hepatic M1 inflammatory macrophages and cytotoxic T cells showed intracellular inflammatory cytokines which were associated with high levels of IL6, IFNγ and IL17 plasmatic cytokines and CCL2 chemokine. These findings correlated with an increase in hepatic parasite load in I+MFD group demonstrated by qPCR assays. The recruitment of hepatic B lymphocytes, NK and dendritic cells was enhanced by MFD, and it was intensified by parasitic infection. These results were TLR4 signaling dependent. Flow cytometry and confocal microscopy analysis demonstrated that the reactive oxygen species and peroxinitrites produced by liver inflammatory leukocytes of MFD group were also exacerbated by parasitic infection in our NASH model.

CONCLUSIONS

We highlight that a medium fat diet by itself is able to induce steatohepatitis. Our results also suggest a synergic effect between damage associated with molecular patterns generated during NASH and parasitic infection, revealing an intense cross-talk between metabolically active tissues, such as the liver, and the immune system. Thus, T. cruzi infection must be considered as an additional risk factor since exacerbates the inflammation and accelerates the development of hepatic injury.

Chronic HCV infection increases cardiac left ventricular mass index in normotensive patients

BACKGROUND & AIMS

Left ventricular hypertrophy (LVH), is an independent predictor for cardiovascular events. We investigated if chronic hepatitis C virus (HCV) infection and the related insulin resistance (IR)/hyperinsulinemia could influence the increase of left ventricular mass (LVM).

METHODS

We enrolled 260 outpatients matched for age, body mass index, gender, ethnicity: 52 with never-treated uncomplicated chronic HCV infection (HCV(+)), 104 never-treated hypertensives (HT) and 104 healthy subjects (NT). LVM was calculated according to the Devereux formula and indexed for body surface area. The following laboratory parameters were measured: fasting plasma glucose and insulin, total, LDL- and HDL-cholesterol, triglyceride, creatinine, e-GFR-EPI, HOMA. Quantitative HCV-RNA was assessed by PCR.

RESULTS

HCV(+) patients with respect to healthy normotensive subjects had an increased LVMI (100 ± 23 vs. 83 ± 15 g/m(2); p < 0.0001), similar to that observed in HT group (103 ± 25 g/m(2)). Regarding biochemical variables, HCV(+) patients, in comparison with normotensive healthy subjects, had higher triglyceride, creatinine, fasting insulin and HOMA (3.2 ± 1.3 vs. 2.5 ± 1.0; p < 0.0001). At linear regression analysis, the correlation between LVMI and HOMA was similar in HT (r = 0.528, p < 0.0001) and HCV(+) (r = 0.489, p < 0.0001) groups. At multiple regression analysis, HOMA resulted the major determinant of LMVI in all groups, explaining respectively 21.8%, 27.8%, and 23.9% of its variation in NT, HT and HCV(+). At correlational analysis HCV-RNA and HOMA demonstrated a strong and linear relationship between them, explaining the 72.4% of their variation (p = 0.022).

CONCLUSIONS

We demonstrated a significant and direct correlation between HOMA and LVMI in patients with chronic HCV infection, similar to that observed in hypertensives.

Hepatitis C virus NS5A protein enhances gluconeogenesis through upregulation of Akt-/JNK-PEPCK signalling pathways

BACKGROUND & AIMS

Hepatitis C virus (HCV) infection is highly associated with the type 2 diabetes mellitus, but the detailed mechanisms by which the viral proteins are involved in the clinical outcome remain unclear.

METHODS

A cDNA microarray analysis was performed following introducing an NS5A-encoding plasmid or a control vector into a mouse system by hydrodynamics- based transfection. Differentially expressed genes that are associated with gluconeogenesis were selected and their expression levels in HCV patients, in NS5A-expressing systems, and in the viral subgenomic replicon system were further examined by real-time quantitative polymerase chain reaction and Western blot analysis.

RESULTS

Differential gene expression including an upregulation of the gluconeogenic rate-limiting enzyme phosphoenolpyruvate carboxykinase (PEPCK) compared with controls was detected in mouse hepatocytes expressing HCV NS5A and in HCV patients with diabetes. In addition, an NS5A-dependent increase in glucose production was demonstrated in human primary hepatocytes. The upregulation of PEPCK and peroxisome proliferator-activated receptor-c coactivator-1a (PGC-1a) were also detected in NS5A-expressing cells and in the viral genotype 1b subgenomic replicon system. Further studies demonstrated that the NS5A-mediated upregulation of PEPCK and PGC-1a genes were resulted from the activation of PI3K-Akt and JNK signalling pathways. In addition, the expression levels of the forkhead transcription factor FoxO1 and the liver-enriched transcription factor HNF-4a were increased in HCV NS5A expressing cells.

CONCLUSIONS

By upregulating the expression of PEPCK gene via its transactivators FoxO1 and HNF-4a, and the coactivator PGC-1a, the NS5A promotes the production of hepatic glucose which may contribute to the development of HCV-associated type 2 diabetes mellitus.

The central question of type 2 diabetes

Type 2 diabetes (T2D) represents a significant global epidemic with more than 285 million people affected worldwide. Regulating glycemia in T2D patients can be partially achieved with currently available treatment, but intensive research during the last decades have led to the discovery of modified compounds or new targets that could represent great hope for safe and effective treatment in the future. Among them, targets in the CNS that are known to control feeding and body weight have been also shown to exert glucoregulatory actions, and could be a key in the development of a new generation of drugs in the field of T2D. Such drugs would be of great interest since they can be used both in the treatment of diabetes and obesity. This patent review aims to establish an overview of recent patents disclosing new therapeutic opportunities targeting peripheral, as well as central targets for the treatment of T2D.

Regulation of FOXO3 by phosphorylation and methylation in hepatitis C virus infection and alcohol exposure

Hepatitis C virus (HCV) infection produces chronic liver injury that is significantly exacerbated by alcohol consumption. While multiple mechanisms contribute to this synergy, a viral-induced loss of antioxidant responses has been shown to play an important role. This study examined the effects of HCV infection and alcohol on the regulation of the transcription factor FOXO3, an important regulator of Mn-superoxide dismutase (SOD2) expression, a tumor suppressor, and a component of the hepatic antioxidant response system. FOXO3 was activated by either HCV or alcohol alone but suppressed by the combination. To understand this paradoxical result, we applied a capillary isoelectric focusing (IEF) method to determine the pattern of FOXO3 posttranslational modifications (PTMs) induced by HCV and alcohol. We observed the presence of multiple different nuclear and cytosolic species of FOXO3 and used antiphosphoserine, acetyl-lysine, methylarginine, and ubiquitin antibodies to identify the PTM patterns present in each species. HCV caused multiple changes including phosphorylation of FOXO3 at S-574, a novel c-Jun N-terminal kinase (JNK) site, which promoted nuclear translocation and transcription. Ethanol suppressed arginine-methylation of FOXO3 promoting nuclear export and degradation of the JNK phosphorylated form. Human liver biopsy samples showed the presence of the HCV-specific form of FOXO3 in HCV-infected livers but not in normal liver or nonalcoholic steatohepatitis.

CONCLUSION

The development of this novel IEF method for the simultaneous quantification of differently modified FOXO3 species allowed us to demonstrate how HCV and alcohol combine to modify a complex pattern of FOXO3 PTMs that contribute to pathogenesis. This approach will allow further dissection of the role of protein PTMs in viral liver disease.

Metabolic factors and chronic hepatitis C: a complex interplay

In the last years, several lines of evidence showed how metabolic factors may influence the natural history of patients with chronic hepatitis C. Chronic HCV infection is able to perturb the metabolic homeostasis of the host, in a context of complex interactions where pre-existent metabolic status and genetic background play an important role, allowing us to state that HCV infection is a systemic disease. In this review, we discuss the most recent lines of evidence on the main metabolic factors that are known to be associated with CHC, namely, insulin resistance/type 2 diabetes, steatosis, visceral obesity, atherosclerosis, vitamin D, menopause, fructose and coffee intake, lipoproteins, methylenetetrahydrofolate reductase status, and hyperuricaemia. In particular, we focus on the pathophysiological mechanisms underlying the correlation between HCV infection and metabolic disorders, the impact of metabolic factors on the progression of liver and non-liver-related diseases, and, on the contrary, the possible influence of chronic HCV infection on metabolic features. In this setting, the importance of a multifaceted evaluation of CHC patients and a prompt correction of modifiable metabolic risk factors should be emphasized.

Managing diabetes in patients with chronic liver disease

Diabetes and chronic liver disease (CLD) are common long-term conditions in the developed and developing world. The 2 conditions often coexist, and there is evidence to suggest that diabetes can have a significant adverse effect on patients with CLD, leading to increased complications and premature mortality. While diabetes, nonalcoholic fatty liver disease, and nonalcoholic steatohepatitis (NASH) appear to have common origins related to obesity and insulin resistance, diabetes is also common among patients with alcoholic and viral CLD. In patients with NASH, improvement in metabolic indices appears to reduce the progression of CLD. It is not clear whether improving glycemic control in other forms of CLD leads to improved outcomes. Managing diabetes in patients with CLD can be challenging because many antihyperglycemic therapies are contraindicated or must be used with care. Metformin and pioglitazone may be useful in patients with NASH, but sulfonylureas and insulin must be used with caution, as hypoglycemia may be a problem. Insulin doses frequently need to be reduced in patients with CLD. Newer glycemic agents have not been widely used in patients with CLD, but bariatric surgery may lead to significant improvement in liver indices in patients with NASH. Management of patients with diabetes and CLD may be enhanced by using a multidisciplinary approach.