Factors Associated with Insulin Resistance in Patients with Chronic HCV Genotype 1 Infection without Obesity or Type 2 Diabetes

The Effects of Viruses on Insulin Sensitivity and Blood-Brain Barrier Function

In this review manuscript, we discuss the effects of select common viruses on insulin sensitivity and blood-brain barrier (BBB) function and the potential overlapping and distinct mechanisms involved in these effects. More specifically, we discuss the effects of human immunodeficiency virus (HIV), herpes, hepatitis, influenza, respiratory syncytial virus (RSV), and SARS-CoV-2 viruses on insulin sensitivity and BBB function and the proposed underlying mechanisms. These viruses differ in their ability to be transported across the BBB, disrupt the BBB, and/or alter the function of the BBB. For RSV and SARS-CoV-2, diabetes increases the risk of infection with the virus, in addition to viral infection increasing the risk for development of diabetes. For HIV and hepatitis C and E, enhanced TNF-a levels play a role in the detrimental effects. The winter of 2022-2023 has been labeled as a tridemic as influenza, RSV, and COVID-19 are all of concern during this flu season. There is an ongoing discussion about whether combined viral exposures of influenza, RSV, and COVID-19 have additive, synergistic, or interference effects. Therefore, increased efforts are warranted to determine how combined viral exposures affect insulin sensitivity and BBB function.

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.

Review on the recent progress in the development of fluorescent probes targeting enzymes

Enzymes are very important for biological processes in a living being, performing similar or multiple tasks in and out of cells, tissues and other organisms at a particular location. The abnormal activity of particular enzyme usually caused serious diseases such as Alzheimer's disease, Parkinson's disease, cancers, diabetes, cardiovascular diseases, arthritis etc. Hence, nondestructive and real-time visualization for certain enzyme is very important for understanding the biological issues, as well as the drug administration and drug metabolism. Fluorescent cellular probe-based enzyme detectionin vitroandin vivohas become broad interest for human disease diagnostics and therapeutics. This review highlights the recent findings and designs of highly sensitive and selective fluorescent cellular probes targeting enzymes for quantitative analysis and bioimaging.

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.

Hepatitis C virus infection is associated with hepatic and adipose tissue insulin resistance that improves after viral cure

BACKGROUND

Chronic hepatitis C (CHC) is associated with systemic insulin resistance, yet there are limited data on the tissue-specific contribution in vivo to this adverse metabolic phenotype, and the effect of HCV cure.

METHODS

We examined tissue-specific insulin sensitivity in a cohort study involving 13 patients with CHC compared to 12 BMI-matched healthy control subjects. All subjects underwent a two-step clamp incorporating the use of stable isotopes to measure carbohydrate and lipid flux (hepatic and global insulin sensitivity) with concomitant subcutaneous adipose tissue microdialysis and biopsy (subcutaneous adipose tissue insulin sensitivity). Investigations were repeated in seven patients with CHC following antiviral therapy with a documented sustained virological response.

RESULTS

Adipose tissue was more insulin resistant in patients with CHC compared to healthy controls, as evidence by elevated glycerol production rate and impaired insulin-mediated suppression of both circulating nonesterified fatty acids (NEFA) and adipose interstitial fluid glycerol release during the hyperinsulinaemic euglycaemic clamp. Hepatic and muscle insulin sensitivity were similar between patients with CHC and controls. Following viral eradication, hepatic insulin sensitivity improved as demonstrated by a reduction in endogenous glucose production rate. In addition, circulating NEFA decreased with sustained virological response (SVR) and insulin was more effective at suppressing adipose tissue interstitial glycerol release with a parallel increase in the expression of insulin signalling cascade genes in adipose tissue consistent with enhanced adipose tissue insulin sensitivity.

CONCLUSION

Chronic hepatitis C patients have profound subcutaneous adipose tissue insulin resistance in comparison with BMI-matched controls. For the first time, we have demonstrated that viral eradication improves global, hepatic and adipose tissue insulin sensitivity.

Targeted Delivery of a γ-Glutamyl Transpeptidase Activatable Near-Infrared-Fluorescent Probe for Selective Cancer Imaging

The noninvasive and specific detection of cancer cells in living subjects has been essential for the success of cancer diagnoses and treatments. Herein, we report a strategy of combining an α_vβ₃-integrin-receptor-targetable ligand, c-RGD, with the γ-glutamyl transpeptidase (GGT)-recognizable substrate, γ-glutamate (γ-Glu), to develop a tumor-targeting and GGT-activatable near-infrared (NIR)-fluorescent probe for the noninvasive imaging of tumors in living mice. We demonstrated that the probe's fluorescence was off initially, but when the γ-Glu in the probe was specifically cleaved by GGT, the fluorescent product was released and could be selectively taken up by U87MG-tumor cells via α_vβ₃-receptor-mediated endocytosis. Remarkably, enhanced intracellular NIR fluorescence distributed mainly in the lysosomes was observed in the tumor cells only, showing that the probe was capable of differentiating the tumor cells from the GGT-positive, α_vβ₃-deficient normal cells. Moreover, the probe also showed a high selectivity for the real-time and noninvasive detection of GGT activity in xenograft U87MG tumors following iv administration. This study reveals the advantage of using a combination of receptor-mediated cell uptake and molecular-target-triggered activation to design molecular probes for improved cancer imaging, which could facilitate effective cancer diagnoses.

High prevalence of insulin resistance among Brazilian chronic hepatitis C patients

OBJECTIVE

This study aims to estimate the prevalence of insulin resistance (IR) among chronic hepatitis C (CHC) patients and their related laboratory and demographic data.

SUBJECTS AND METHODS

In this study, non-diabetic CHC patients referred to Viral Hepatitis Ambulatories from Rio de Janeiro (Brazil) donated blood samples. Insulin was measured using a chemiluminescence immunoassay. IR was determined by HOMA-IR, where HOMA-IR > 2 was defined as IR.

RESULTS

A total of 214 CHC patients were recruited (123 females aged 53.6 years ± 10.9 years). IR was present in 133 patients (62.1%) and was associated in bivariate analysis to higher mean values of age (p = 0.040), triglycerides (p = 0.032), glucose (p = 0.000), insulin (p = 0.000), waist circumference (p = 0.001), and body mass index (p = 0.007); however, none of these variables were significant in the multivariate analysis.

CONCLUSIONS

The high prevalence of IR was observed among CHC patients, and there was no difference in clinical or laboratory parameters when both groups were compared in the multivariate analysis. This high IR prevalence could lead to a high risk for development of cardiovascular disease and metabolic disorders.

Metabolic Dysregulation in Hepacivirus Infection of Common Marmosets (Callithrix jacchus)

Chronic hepatitis C has been associated with metabolic syndrome that includes insulin resistance, hepatic steatosis and obesity. These metabolic aberrations are risk factors for disease severity and treatment outcome in infected patients. Experimental infection of marmosets with GBV-B serves as a tangible, small animal model for human HCV infection, and while virology and pathology are well described, a full investigation of clinical disease and the metabolic milieu is lacking. In this study six marmosets were infected intravenously with GBV-B and changes in hematologic, serum biochemical and plasma metabolic measures were investigated over the duration of infection. Infected animals exhibited signs of lymphocytopenia, but platelet and RBC counts were generally stable or even increased. Although most animals showed a transient decline in blood glucose, infection resulted in several fold increases in plasma insulin, glucagon and glucagon-like peptide 1 (GLP-1). All infected animals experienced transient weight loss within the first 28 days of infection, but also became hypertriglyceridemic and had up to 10-fold increases in adipocytokines such as resistin and plasminogen activator inhibitor 1 (PAI-1). In liver, moderate to severe cytoplasmic changes associated with steatotic changes was observed microscopically at 168 days post infection. Collectively, these results suggest that GBV-B infection is accompanied by hematologic, biochemical and metabolic abnormalities that could lead to obesity, diabetes, thrombosis and atherosclerosis, even after virus has been cleared. Our findings mirror those found in HCV patients, suggesting that metabolic syndrome could be conserved among hepaciviruses, and both mechanistic and interventional studies for treating HCV-induced metabolic complications could be evaluated in this animal model.

Systemic manifestations of hepatitis C infection

Chronic hepatitis C (HCV) is a common infection affecting 185 million people worldwide. The most common manifestation of chronic HCV is progressive liver fibrosis, cirrhosis, liver failure and hepatocellular carcinoma. However, several systemic manifestations of HCV have been recognized and reported in the literature. The purpose of this review is to assimilate published literature based on evidence to categorize these extrahepatic manifestations with the likelihood of a causal association with HCV. Exciting recent developments have resulted in simple all oral interferon-free highly effective therapy for HCV. However, this treatment is also expensive and less accessible to most affected individuals as treatment recommendations are based on stage of liver fibrosis. Expanding the scope of HCV therapy to those with extrahepatic manifestations beyond what is currently recommended will significantly reduce the morbidity and mortality in this aging population.