Hepatitis C virus neuroinvasion: identification of infected cells

Hepatitis C virus infection, and neurological and psychiatric disorders - A review

An association between hepatitis C virus infection and neuropsychiatric symptoms has been proposed for some years. A variety of studies have been undertaken to assess the nature and severity of these symptoms, which range from fatigue and depression to defects in attention and verbal reasoning. There is evidence of mild neurocognitive impairment in some patients with HCV infection, which is not fully attributable to liver dysfunction or psychosocial factors. Further evidence of a biological cerebral effect has arisen from studies using magnetic resonance spectroscopy; metabolic abnormalities correlate with cognitive dysfunction and resemble the patterns of neuroinflammation that have been described in HIV infection. Recent research has suggested that, in common with HIV infection, HCV may cross the blood brain barrier leading to neuroinflammation. Brain microvascular endothelial cells, astrocytes and microglia may be minor replication sites for HCV. Importantly, patient reported outcomes improve following successful antiviral therapy. Further research is required to elucidate the molecular basis for HCV entry and replication in the brain, and to clarify implications and recommendations for treatment.

HCV encephalopathy - an artefact due to medical care?

Anti-HCV positive individuals frequently complain about chronic disabling fatigue, mood alterations and deficits in concentration and memory. Several data provide evidence that such alterations are unrelated to hepatitis C virus (HCV) viremia. Thus, merely being exposed to HCV in the past may be sufficient to trigger, but the HCV exposure itself. This commentary reviews the available data upon this topic with special reference to the paper by Lowry and colleagues published in this issue of the Journal of Viral hepatitis. We will carefully discuss scientific reasons, why HCV may be directly involved in the development of neuropsychiatric symptoms independent from ongoing detectable viremia, as suggested by epidemiological data.

Is psychosocial and cognitive dysfunction misattributed to the virus in hepatitis C infection? Select psychosocial contributors identified

Chronic hepatitis C is associated with health-related quality of life and cognitive impairments, even in mild disease. Recent evidence demonstrating hepatitis C virus (HCV) neurotropism has strengthened a neuropathophysiological hypothesis. However, sample heterogeneity confounds study outcomes. A uniquely homogeneous cohort of Irish women, following an iatrogenic HCV outbreak, offers a rare opportunity to control for HCV chronicity and the virus' purported impact on quality of life and cognition. A multi site, three-group, cross-sectional design was employed. Noncirrhotic, iatrogenically infected women, developing either acute or chronic infection, were recruited from prospective tertiary-care liver clinics and the community. Well-matched healthy controls were also recruited. All participants completed a psychosocial survey and were invited to undergo a comprehensive neuropsychological test battery. Significantly distressed psychosocial symptom profiles were observed in those with an iatrogenic HCV exposure history, which was independent of viral chronicity. Chronic and cleared HCV cohorts were not differentiated from each other. Two distinct subgroups, demarcated along 'impaired' vs 'nonimpaired' quality-of-life reports, were clearly identified and logistic regression analysis identified depressed mood and cognitive fatigue, rather than viral status, as statistically significant predictors of group membership. Compared with matched controls, significant cognitive impairments were not observed in either HCV cohort. Our findings provide strong evidence of nonviral factors accounting for quality of life impairment in chronic HCV and they also appear to question existing reports of cognitive dysfunction in mild disease. Depressed mood and cognitive fatigue appear to be critical psychosocial mediators of reduced quality-of-life and we hypothesize that metabolite abnormalities reported in HCV samples may also be confounded by these factors, given the associated literature.

Alcohol intake alters immune responses and promotes CNS viral persistence in mice

Chronic hepatitis C virus (HCV) infection leads to progressive liver disease and is associated with a variety of extrahepatic effects, including central nervous system (CNS) damage and neuropsychiatric impairments. Alcohol abuse can exacerbate these adverse effects on brain and behavior, but the molecular mechanisms are not well understood. This study investigated the role of alcohol in regulating viral persistence and CNS immunopathology in mice infected with lymphocytic choriomeningitis virus (LCMV), a model for HCV infections in humans. Female and male BALB/c mice (n=94) were exposed to alcohol (ethanol; EtOH) and water (or water only) using a two-bottle choice paradigm, followed one week later by infection with either LCMV clone 13 (causes chronic infection similar to chronic HCV), LCMV Armstrong (causes acute infection), or vehicle. Mice were monitored for 60days post-infection and continued to receive 24-h access to EtOH and water. Animals infected with LCMV clone 13 drank more EtOH, as compared to those with an acute or no viral infection. Six weeks after infection with LCMV clone 13, mice with EtOH exposure evidenced higher serum viral titers, as compared to mice without EtOH exposure. EtOH intake was also associated with reductions in virus-specific CD8(+) T cell frequencies (particularly CD11a(hi) subsets) and evidence of persistent CNS viremia in chronically infected mice. These findings support the hypothesis that EtOH use and chronic viral infection can result in combined toxic effects accelerating CNS damage and neuropsychiatric dysfunction and suggest that examining the role of EtOH in regulating viral persistence and CNS immunopathology in mice infected with LCMV can lead to a more comprehensive understanding of comorbid alcohol use disorder and chronic viral infection.

Hepatitis C virus as a systemic disease: reaching beyond the liver

Chronic hepatitis C (CHC) is associated with multiple extrahepatic manifestations that may impact infected patients. The mechanisms through which these develop include those which are immunological, in which the chronic persistence of virus leads to the circulation of immune complexes (mixed cryoglobulinemia) and other autoimmune phenomena, and those which are virological and related to the extrahepatic tropism of the virus to other tissues. It is estimated that 40-74 % of patients with CHC may develop at least one extrahepatic manifestation during the course of the disease. Extrahepatic syndromes may represent the first signal of hepatitis C infection in some patients. CHC is associated with a four-fold increased risk of insulin resistance and type 2 diabetes mellitus; with cardiovascular disease in 17-37 % of patients; and with increased risk for cerebrovascular deaths, with a biological gradient of cerebrovascular mortality correlating with an increasing serum viral load. CHC is also associated with lymphoproliferative disorders, particularly non-Hodgkin B-cell lymphoma. The kidney is involved in 35-60 % of patients with CHC-associated mixed cryoglobulinemia. The prevalent type of glomerulonephritis associated with mixed cryoglobulinemia is membranoproliferative glomerulonephritis. In 30 % of cases, renal involvement begins with a nephritis syndrome and acute renal failure, while in 55 % there is only mild hematuria, microalbuminuria, proteinuria and renal insufficiency. CHC is also associated with cognitive impairment, especially in memory and concentration. Thus, extrahepatic CHC manifestations involve multiple organ systems outside the liver linked to a variety of comorbidities which may lead to significantly increased mortality from non-liver-related events.

Cerebral microglia activation in hepatitis C virus infection correlates to cognitive dysfunction

Hepatitis C virus (HCV) infection may induce chronic fatigue and cognitive dysfunction. Virus replication was proven within the brain and HCV-positive cells were identified as microglia and astrocytes. We hypothesized that cerebral dysfunction in HCV-afflicted patients is associated with microglia activation. Microglia activation was assessed in vivo in 22 patients with chronic HCV infection compared to six healthy controls using [(11) C]-PK11195 Positron Emission Tomography (PET) combined with magnetic resonance tomography for anatomical localization. Patients were subdivided with regard to their PCR status, Fatigue Impact Scale score (FIS) and attention test sum score (ATS). A total of 12 patients (54.5%) were HCV PCR positive [of which 7 (58.3%) had an abnormal FIS and 7 (58.3%) an abnormal ATS], 10 patients (45.5%) were HCV PCR negative (5 (50%) each with an abnormal FIS or ATS). Patients without attention deficits showed a significantly higher accumulation of [(11) C]-PK11195 in the putamen (P = 0.05), caudate nucleus (P = 0.03) and thalamus (P = 0.04) compared to controls. Patients with and without fatigue did not differ significantly with regard to their specific tracer binding in positron emission tomography. Preserved cognitive function was associated with significantly increased microglia activation with predominance in the basal ganglia. This indicates a probably neuroprotective effect of microglia activation in HCV-infected patients.

Hepatitis C virus and neurological damage

Chronic hepatitis C virus (HCV) infection exhibits a wide range of extrahepatic complications, affecting various organs in the human body. Numerous HCV patients suffer neurological manifestations, ranging from cognitive impairment to peripheral neuropathy. Overexpression of the host immune response leads to the production of immune complexes, cryoglobulins, as well as autoantibodies, which is a major pathogenic mechanism responsible for nervous system dysfunction. Alternatively circulating inflammatory cytokines and chemokines and HCV replication in neurons is another factor that severely affects the nervous system. Furthermore, HCV infection causes both sensory and motor peripheral neuropathy in the mixed cryoglobulinemia as well as known as an important risk aspect for stroke. These extrahepatic manifestations are the reason behind underlying hepatic encephalopathy and chronic liver disease. The brain is an apt location for HCV replication, where the HCV virus may directly wield neurotoxicity. Other mechanisms that takes place by chronic HCV infection due the pathogenesis of neuropsychiatric disorders includes derangement of metabolic pathways of infected cells, autoimmune disorders, systemic or cerebral inflammation and alterations in neurotransmitter circuits. HCV and its pathogenic role is suggested by enhancement of psychiatric and neurological symptoms in patients attaining a sustained virologic response followed by treatment with interferon; however, further studies are required to fully assess the impact of HCV infection and its specific antiviral targets associated with neuropsychiatric disorders.

Reduced cerebral cortical thickness in Non-cirrhotic patients with hepatitis C

Hepatitis C virus (HCV) infection is associated with fatigue, depression, and cognitive impairment even in the absence of severe liver fibrosis or cirrhosis. HCV has been hypothesised to cause neurodegenerative changes through low-grade neuroinflammation. Our aim was to examine whether cortical thickness (CTh) differs between chronic HCV patients and healthy controls, suggestive of cortical atrophy. In this case-control study 43 HCV patients without severe liver fibrosis, substance abuse, or comorbid HIV or hepatitis B virus infection, and 43 age and sex matched controls underwent MRI. Cortical thickness was measured using a surface based approach. Participants underwent semi-structured psychiatric interview and fatigue was assessed using the fatigue severity scale. HCV was associated with higher fatigue scores, and 58 % of HCV patients suffered from significant fatigue (p < 0.0001). Depression was observed in 16 % of patients. Areas of significantly reduced CTh were found in both left and right occipital cortex and in the left frontal lobe after correction for multiple comparisons (p < 0.05). No association between fatigue, former substance abuse, or psychotropic medication and CTh was found. No overall difference in cerebral white and grey matter volume was found. The findings support the hypothesis that HCV is associated with neurodegenerative changes.

Serum-derived hepatitis C virus 1a infection of human astrocyte cell line SVG

Neuroinvasion of hepatitis C virus (HCV) is evidenced by recent clinical studies. In this study, serum-derived HCV infection of astrocytes was analysed. Astrocytes were infected with HCV-positive serum, and viral replication was assessed on different days postinfection. RT-PCR was positive for HCV-negative strand on 5th and 7th day postinfection in the HCV-positive serum-infected astrocytes. Real-time RNA count in the cell culture supernatant was steadily increasing from day 3 to day 7. To reconfirm the viral replication, astrocytes were treated with an antiviral before the serum infection, and the antiviral treatment significantly reduced the viral RNA count. Further, the virus-infected cells stained positive for the presence of viral core protein. Electron microscopy revealed the presence of HCV-like particles in the astrocyte cell culture supernatant. In conclusion, serum-derived HCV replicates in human astrocyte cell line SVG.

Apolipoprotein E-ε4 deficiency and cognitive function in hepatitis C virus-infected patients

Hepatitis C virus (HCV) causes not only liver damage in certain patients but can also lead to neuropsychiatric symptoms. Previous studies have shown that the type 4 allele of the gene for apolipoprotein E (APOE) is strongly protective against HCV-induced damage in liver. In this study, we have investigated the possibility that APOE genotype is involved in the action of HCV in brain. One hundred HCV-infected patients with mild liver disease underwent a neurological examination and a comprehensive psychometric testing of attention and memory function. In addition, patients completed questionnaires for the assessment of fatigue, health-related quality of life and mood disturbances. Apolipoprotein E gene genotyping was carried out on saliva using buccal swabs. The APOE-ε4 allele frequency was significantly lower in patients with an impairment of working memory, compared to those with a normal working memory test result (P = 0.003). A lower APOE-ε4 allele frequency was also observed in patients with definitely altered attention ability (P = 0.008), but here, the P-value missed the level of significance after application of the Bonferroni correction. Our data suggest that the APOE-ε4 allele is protective against attention deficit and especially against poor working memory in HCV-infected subjects with mild liver disease. Considering the role of apolipoprotein E in the life cycle of the virus, the findings shed interesting new light upon possible pathomechanisms behind the development of neuropsychiatric symptoms in hepatitis C infection.

Extrahepatic morbidity and mortality of chronic hepatitis C

Chronic hepatitis C virus (HCV) infection is associated with several extrahepatic manifestations. Patients with HCV may develop mixed cryoglobulinemia and its sequelae, ranging from cutaneous and visceral vasculitis to glomerulonephritis and B-cell non-Hodgkin lymphoma. HCV-infected patients have increased rates of insulin resistance, diabetes, and atherosclerosis, which may lead to increased cardiovascular morbidity and mortality. Neurological manifestations of HCV infection include fatigue and cognitive impairment. The mechanisms causing the extrahepatic effects of HCV infection are likely multifactorial and may include endocrine effects, HCV replication in extrahepatic cells, or a heightened immune reaction with systemic effects. Successful eradication of HCV with interferon alfa and ribavirin was shown to improve some of these extrahepatic effects; sustained virological response is associated with resolution of complications of cryoglobulinemia, reduced levels of insulin resistance, reduced incidence of diabetes and stroke, and improved fatigue and cognitive functioning. The availability of new interferon-free, well-tolerated anti-HCV treatment regimens is broadening the spectrum of patients available for therapy, including those in whom interferon was contraindicated, and will likely result in greater improvements in the extrahepatic manifestations of HCV. If these regimens are shown to confer significant benefit in the metabolic, cardiovascular, or neuropsychiatric conditions associated with HCV infection, extrahepatic manifestations of HCV may become a major indication for treatment even in the absence of liver disease.

Neuroretinal Degeneration in HIV Patients Without Opportunistic Ocular Infections in the cART Era

Subtle structural and functional retinal abnormalities, termed 'HIV-associated Neuroretinal Disorder (HIV-NRD)', have been reported in HIV patients receiving combination antiretroviral therapy (cART), without infectious retinitis or any apparent fundus abnormalities otherwise. In this review, we provide an overview of studies investigating HIV-NRD in HIV patients without opportunistic ocular infections in the cART era, and try to elucidate underlying mechanisms and associated risk factors. Most studies focused on patients with severe immune-deficiency and demonstrated that patients with nadir CD4 counts<100 cells/μL are most at risk for neuroretinal damage, with a thinner retinal nerve fiber layer, subtle loss of color vision and/or contrast sensitivity, visual field deficits, and subnormal electrophysiological responses. In contrast, alterations in retinal vascular calibers and retinal blood flow were not associated with nadir CD4 counts, but instead with detectable viremia, suggesting a role for (chronic) inflammation in microvascular damage. Although the alterations in visual function are subtle, they can lead to difficulties in activities, such as reading or driving, thereby affecting quality of life. Since HIV has become a chronic disease, its long-term effects with respect to visual function loss become more important, as is recently emphasized by a longitudinal study, reporting that AIDS patients with HIV-NRD have higher risks of developing bilateral visual impairment and even blindness than patients without HIV-NRD. The question remains whether patients with high (>350 cells/μL) nadir CD4 counts and well-suppressed HIV infection on cART remain at risk for HIV-NRD, as this group constitutes a growing part of the aging HIV-infected population.

Human hepatic stellate cells are not permissive for hepatitis C virus entry and replication

BACKGROUND

Chronic HCV infection is associated with the development of hepatic fibrosis. The direct role of HCV in the fibrogenic process is unknown. Specifically, whether HCV is able to infect hepatic stellate cells (HSCs) is debated.

OBJECTIVE

To assess whether human HSCs are susceptible to HCV infection.

DESIGN

We combined a set of original HCV models, including the infectious genotype 2a JFH1 model (HCVcc), retroviral pseudoparticles expressing the folded HCV genotype 1b envelope glycoproteins (HCVpp) and a subgenomic genotype 1b HCV replicon, and two relevant cellular models, primary human HSCs from different patients and the LX-2 cell line, to assess whether HCV can infect/replicate in HSCs.

RESULTS

In contrast with the hepatocyte cell line Huh-7, neither infectious HCVcc nor HCVpp infected primary human HSCs or LX-2 cells. The cellular expression of host cellular factors required for HCV entry was high in Huh-7 cells but low in HSCs and LX-2 cells, with the exception of CD81. Finally, replication of a genotype 2a full-length RNA genome and a genotype 1b subgenomic replicon was impaired in primary human HSCs and LX-2 cells, which expressed low levels of cellular factors known to play a key role in the HCV life-cycle, suggesting that human HSCs are not permissive for HCV replication.

CONCLUSIONS

Human HSCs are refractory to HCV infection. Both HCV entry and replication are deficient in these cells, regardless of the HCV genotype and origin of the cells. Thus, HCV infection of HSCs does not play a role in liver fibrosis. These results do not rule out a direct role of HCV infection of hepatocytes in the fibrogenic process.

Hepatitis C Virus NS3 Mediated Microglial Inflammation via TLR2/TLR6 MyD88/NF-κB Pathway and Toll Like Receptor Ligand Treatment Furnished Immune Tolerance

Background

Recent evidence suggests the neurotrophic potential of hepatitis C virus (HCV). HCV NS3 protein is one of the potent antigens of this virus mediating inflammatory response in different cell types. Microglia being the immune surveillance cells in the central nervous system (CNS), the inflammatory potential of NS3 on microglia was studied. Role of toll like receptor (TLR) ligands Pam2CSK3 and Pam3CSK4 in controlling the NS3 mediated microglial inflammation was studied using microglial cell line CHME3.

Methods

IL (Interleukin)-8, IL-6, TNF-α (Tumor nicrosis factor alpha) and IL-1β gene expressions were measured by semi quantitative RT-PCR (reverse transcription-PCR). ELISA was performed to detect IL-8, IL-6, TNF-α, IL-1β and IL-10 secretion. FACS (Flourescent activated cell sorting) was performed to quantify TLR1, TLR2, TLR6, MyD88 (Myeloid differntiation factor 88), IkB-α (I kappaB alpha) and pNF-κB (phosphorylated nuclear factor kappaB) expression. Immunofluorescence staining was performed for MyD88, TLR6 and NF-κB (Nuclear factor kappaB). Student's t-test or One way analysis of variance with Bonferoni post hoc test was performed and p < 0.05 was considered significant.

Results

Microglia responded to NS3 by secreting IL-8, IL-6, TNF-α and IL-1β via TLR2 or TLR6 mediated MyD88/NF-κB pathway. Transcription factor NF-κB was involved in activating the cytokine gene expression and the resultant inflammatory response was controlled by NF-κB inhibitor, Ro106-9920, which is known to down regulate pro-inflammatory cytokine secretion. Activation of the microglia by TLR agonists Pam3CSK4 and Pam2CSK4 induced immune tolerance against NS3. TLR ligand treatment significantly down regulated pro-inflammatory cytokine secretion in the microglia. IL-10 secretion was suggested as the possible mechanism by which TLR agonists induced immune tolerance. NS3 as such was not capable of self-inducing immune tolerance in microglia.

Conclusion

In conclusion, NS3 protein was capable of activating microglia and the inflammatory response could be controlled via blocking the transcription factor NF-κB, or by treating the microglia with TLR ligands which likely function via secreting anti-inflammatory cytokines such as IL-10. This can have therapeutic potential in controlling HCV mediated neuroinflammation.

Cognitive dysfunction and hepatitis C virus infection

Cognitive dysfunction in patients with chronic hepatitis C virus (HCV) infection is a distinct form of minimal hepatic encephalopathy (MHE). In fact, the majority of HCV-positive patients, irrespective of the grading of liver fibrosis, display alterations of verbal learning, attention, executive function, and memory when they are evaluated by suitable neuropsychological tests. Similarities between the cognitive dysfunction of HCV patients and MHE of patients with different etiologies are unclear. It is also unknown how the metabolic alterations of advanced liver diseases interact with the HCV-induced cognitive dysfunction, and whether these alterations are reversed by antiviral therapies. HCV replication in the brain may play a role in the pathogenesis of neuroinflammation. HCV-related brain dysfunction may be associated with white matter neuronal loss, alterations of association tracts and perfusion. It is unclear to what extent, in patients with cirrhosis, HCV triggers an irreversible neurodegenerative brain damage. New insights on this issue will be provided by longitudinal studies using the protocols established by the diagnostic and statistical manual of mental disorders fifth edition for cognitive disorders. The domains to be evaluated are complex attention; executive functions; learning and memory; perceptual motor functions; social cognition. These evaluations should be associated with fluorodeoxyglucose positron emission tomography and magnetic resonance imaging (MRI) protocols for major cognitive disorders including magnetic resonance spectroscopy, diffusion tensor imaging, magnetic resonance perfusion, and functional MRI. Also, the characteristics of portal hypertension, including the extent of liver blood flow and the type of portal shunts, should be evaluated.

HIV-1, HCV and alcohol in the CNS: potential interactions and effects on neuroinflammation

Approximately 25% of the HIV-1 positive population is also infected with HCV. The effects of alcohol on HIV-1 or HCV infection have been a research topic of interest due to the high prevalence of alcohol use in these infected patient populations. Although it has long been known that HIV-1 infects the brain, it has only been a little more than a decade since HCV infection of the CNS has been characterized. Both viruses are capable of infecting and replicating in microglia and increasing the expression of proinflammatory cytokines and chemokines, including IL-6 and IL-8. Investigations focusing on the effects of HIV-1, HCV or alcohol on neuroinflammation have demonstrated that these agents are capable of acting through overlapping signaling pathways, including MAPK signaling molecules. In addition, HIV-1, HCV and alcohol have been demonstrated to increase permeability of the blood-brain barrier. Patients infected with either HIV-1 or HCV, or those who use alcohol, exhibit metabolic abnormalities in the CNS that result in altered levels of n-acetyl aspartate, choline and creatine in various regions of the brain. Treatment of HIV/HCV co-infection in alcohol users is complicated by drug-drug interactions, as well as the effects of alcohol on drug metabolism. The drug-drug interactions between the antiretrovirals and the antivirals, as well as the effects of alcohol on drug metabolism, complicate existing models of CNS penetration, making it difficult to assess the efficacy of treatment on CNS infection.

Sicca syndrome and dementia in a patient with hepatitis C infection: a case report with unusual bifocal extrahepatic manifestations

INTRODUCTION

Hepatitis C virus (HCV) infections are associated with extrahepatic manifestations in 40-75 % of cases. Sialitis and secondary Sjögren syndrome are well characterized complications of chronic HCV infections but the mechanisms (primary or secondary) leading to xerostomia are not understood. Similarly, brain lesions due to HCV can be primary or secondary but the pathology of primary HCV-related brain lesions is not well described.

CASE REPORT

We report the postmortem case of a 60-year old patient initially presenting with sicca syndrome and dementia. HCV was identified in the brain but not in the salivary glands using transcription-mediated amplification (TMA). Focal sialitis was found in submandibular glands. Neuropathological examination revealed the presence of multiple dot-sized demyelination foci.

CONCLUSION

Sicca syndrome is a common concern in chronic HCV infections and may be due to secondary immune mechanisms (we could not isolate HCV in salivary gland tissues). TMA had never been applied to the detection of viruses in salivary glands and neural tissues and proves to be a promising technique. Neuropathological reports in HCV infections are rare and the lesions we report may be the first characterization of the direct effect of HCV on brain cells. More cases are needed to define the full spectrum of lesions potentially caused by the direct action of the HCV on salivary glands and neural tissues.

Central and peripheral markers of neurodegeneration and monocyte activation in HIV-associated neurocognitive disorders

HIV-associated neurocognitive disorders (HAND) affect up to 50 % of HIV-infected adults, independently predict HIV morbidity/mortality, and are associated with neuronal damage and monocyte activation. Cerebrospinal fluid (CSF) neurofilament subunits (NFL, pNFH) are sensitive surrogate markers of neuronal damage in several neurodegenerative diseases. In HIV, CSF NFL is elevated in individuals with and without cognitive impairment, suggesting early/persistent neuronal injury during HIV infection. Although individuals with severe cognitive impairment (HIV-associated dementia (HAD)) express higher CSF NFL levels than cognitively normal HIV-infected individuals, the relationships between severity of cognitive impairment, monocyte activation, neurofilament expression, and systemic infection are unclear. We performed a retrospective cross-sectional study of 48 HIV-infected adults with varying levels of cognitive impairment, not receiving antiretroviral therapy (ART), enrolled in the CNS Anti-Retroviral Therapy Effects Research (CHARTER) study. We quantified NFL, pNFH, and monocyte activation markers (sCD14/sCD163) in paired CSF/plasma samples. By examining subjects off ART, these correlations are not confounded by possible effects of ART on inflammation and neurodegeneration. We found that CSF NFL levels were elevated in individuals with HAD compared to cognitively normal or mildly impaired individuals with CD4+ T-lymphocyte nadirs ≤200. In addition, CSF NFL levels were significantly positively correlated to plasma HIV-1 RNA viral load and negatively correlated to plasma CD4+ T-lymphocyte count, suggesting a link between neuronal injury and systemic HIV infection. Finally, CSF NFL was significantly positively correlated with CSF pNFH, sCD163, and sCD14, demonstrating that monocyte activation within the CNS compartment is directly associated with neuronal injury at all stages of HAND.

Depression is not associated with peripheral insulin resistance in patients with chronic hepatitis C infection

Depression is common in individuals infected with hepatitis C virus (HCV), and both depression and HCV infection are independently associated with insulin resistance (IR). To evaluate the relationship between depression and IR, among other factors, in an HCV-infected cohort. In this cross-sectional analysis, seventy-four non-type 2 diabetic, noncirrhotic, HCV-infected patients underwent comprehensive clinical, histologic and metabolic evaluation. IR was assessed directly with an insulin suppression test by measuring steady-state plasma glucose (SSPG) levels during continuous infusions of octreotide, glucose and insulin. Logistic regression modelling was used to evaluate predictors associated with depression. Thirty-nine (53%) patients were depressed, and 21 (54%) depressed patients were on at least one antidepressant. A higher estimated proportion of depressed patients were Caucasian (51% vs 20%, P = 0.005), unemployed (69% vs 49%, P = 0.07), heavier smokers (18 pack-years vs 13 pack-years, P = 0.07), on substance abuse therapy (16% vs 3%, P = 0.06) and had lower HDL levels (1.2 mmol/L vs 1.4 mmol/L, P = 0.01). The mean SSPG levels in depressed and nondepressed patients were 7.3 and 8.3 mmol/L (P = 0.45), respectively. In multipredictor adjusted analysis, only Caucasian race (OR 4.19, 95% CI 1.42-12.35, P = 0.009) and lower HDL (OR 0.95, 95% CI 0.89-0.99, P = 0.046) were associated with depression. In conclusion, although prevalent, depression was not associated with peripheral IR in this HCV-infected cohort. Attention to other modifiable factors associated with depression in the HCV-infected population is warranted.

Chronic hepatitis C virus infection and neurological and psychiatric disorders: An overview

Hepatitis C virus (HCV) infection is considered a systemic disease because of involvement of other organs and tissues concomitantly with liver disease. Among the extrahepatic manifestations, neuropsychiatric disorders have been reported in up to 50% of chronic HCV infected patients. Both the central and peripheral nervous system may be involved with a wide variety of clinical manifestations. Main HCV-associated neurological conditions include cerebrovascular events, encephalopathy, myelitis, encephalomyelitis, and cognitive impairment, whereas “brain fog”, depression, anxiety, and fatigue are at the top of the list of psychiatric disorders. Moreover, HCV infection is known to cause both motor and sensory peripheral neuropathy in the context of mixed cryoglobulinemia, and has also been recently recognized as an independent risk factor for stroke. These extrahepatic manifestations are independent of severity of the underlying chronic liver disease and hepatic encephalopathy. The brain is a suitable site for HCV replication, where the virus may directly exert neurotoxicity; other mechanisms proposed to explain the pathogenesis of neuropsychiatric disorders in chronic HCV infection include derangement of metabolic pathways of infected cells, alterations in neurotransmitter circuits, autoimmune disorders, and cerebral or systemic inflammation. A pathogenic role for HCV is also suggested by improvement of neurological and psychiatric symptoms in patients achieving a sustained virologic response following interferon treatment; however, further ad hoc trials are needed to fully assess the impact of HCV infection and specific antiviral treatments on associated neuropsychiatric disorders.

Chronic inflammation and the role for cofactors (hepatitis C, drug abuse, antiretroviral drug toxicity, aging) in HAND persistence

HIV-associated neurocognitive disorders (HAND) is a group of syndromes of varying degrees of cognitive impairment affecting up to 50 % of HIV-infected individuals. The neuropathogenesis of HAND is thought to be driven by HIV invasion and productive replication within brain perivascular macrophages and endogenous microglia, and to some degree by restricted infection of astrocytes. The persistence of HAND in individuals experiencing suppression of systemic HIV viral load with antiretroviral therapy (ART) is incompletely explained, and suggested factors include chronic inflammation, persistent HIV replication in brain macrophages, effects of aging on brain vulnerability, and co-morbid conditions including hepatitis C (HCV) co-infection, substance abuse, and CNS toxicity of ART, among other factors. This review discusses several of these conditions: chronic inflammation, co-infection with HCV, drugs of abuse, aging, and antiretroviral drug effects. Effectively managing these co-morbid conditions in individuals with and without HAND is critical for improving neurocognitive outcomes and decreasing HIV-associated morbidity.

Incidence and long-term outcomes of the human immunodefıciency virus neuroretinal disorder in patients with AIDS

PURPOSE

Patients with AIDS have an abnormality of retina/optic nerve function, manifested as decreased contrast sensitivity (in the absence of ocular opportunistic infections or media opacity), abnormalities on automated perimetry, and loss of retinal nerve fiber layer, even among those with good visual acuity, termed the "human immunodeficiency virus (HIV) neuroretinal disorder." The objectives of this study were to determine the prevalence, incidence, risk factors, and outcomes of HIV neuroretinal disorder.

DESIGN

Prospective cohort study.

PARTICIPANTS

A total of 1822 patients with AIDS without ocular infections or media opacities.

METHODS

Patients with HIV neuroretinal disorder were identified by a contrast sensitivity <1.50 log units in either eye in the absence of ocular opportunistic infections or media opacity.

MAIN OUTCOME MEASURES

Incidence of HIV neuroretinal disorder, mortality, visual impairment (visual acuity ≤20/50), and blindness (≤20/200) on logarithmic visual acuity charts.

RESULTS

Sixteen percent of participants had HIV neuroretinal disorder at enrollment. The estimated cumulative incidence by 20 years after AIDS diagnosis was 51% (95% confidence interval [CI], 46-55). Human immunodeficiency virus neuroretinal disorder was more common in women and African Americans. Risk factors for HIV neuroretinal disorder included hepatitis C infection, low CD4+ T cells, and detectable HIV RNA in the blood. Patients with HIV neuroretinal disorder had a 70% excess mortality versus those without it, even after adjusting for CD4+ T cells and HIV load (hazard ratio [HR], 1.7; 95% CI, 1.3-2.1; P < 0.0001). Patients with HIV neuroretinal disorder had increased risks of bilateral visual impairment (HR, 6.5; 95% CI, 2.6-10.6; P < 0.0001) and blindness (HR, 5.9; 95% CI, 2.8-13.7; P = 0.01) versus those without HIV neuroretinal disorder.

CONCLUSIONS

Human immunodeficiency virus neuroretinal disorder is a common finding among patients with AIDS, and it is associated with an increased mortality and an increased risk of visual impairment. Successful antiretroviral therapy decreases but does not eliminate the risk of HIV neuroretinal disorder.

Cognitive impairment in relation to depression, anxiety and virological response in hepatitis C patients in Egypt

OBJECTIVE

Cognitive impairment commonly occurs in hepatitis C virus (HCV) patients. The objective of this study was to estimate the prevalence and sociodemographic and clinical correlates of cognitive impairment in HCV patients before and after 12 weeks of interferon treatment in comparison with a control group.

METHODS

Hundred and sixteen consecutive HCV patients were included in the study and divided into treated and untreated groups. All patients were assessed using sociodemographic and clinical questionnaire, Montreal Cognitive Assessment Scale (MOCA) and Hospital Anxiety and Depression Scale (HADS) before and after 12 weeks of treatment or observation.

RESULTS

Thirty-eight percent of treated patients showed cognitive impairment at baseline, which increased to 69% after 12 weeks of interferon treatment. This cognitive impairment was reflected in the total MOCA score and in visuo-constructional skills, attention, concentration, working memory, language, and short-term memory, which was not shown by untreated group after 12 weeks of observation. Cognitive impairment was associated with low education, but not with depression, anxiety, or virological response.

CONCLUSIONS

Cognitive impairment is common in HCV patients and increases significantly after interferon treatment. It is not related to depression or anxiety in HCV patients. Future research should focus on prevention, treatment and outcome of cognitive impairment in HCV patients, particularly those receiving interferon therapy.

Absence of neurocognitive effect of hepatitis C infection in HIV-coinfected people

OBJECTIVE

To investigate the effect of hepatitis C virus (HCV) on neurocognitive performance in chronically HIV-infected patients enrolled in the CNS HIV Antiretroviral Therapy Effects Research (CHARTER) study.

METHODS

A total of 1,582 participants in CHARTER who were tested for HCV antibody underwent neurocognitive testing; serum HCV RNA was available for 346 seropositive patients. Neurocognitive performance was compared in 408 HCV-seropositive and 1,174 HCV-seronegative participants and in a subset of 160 seropositive and 707 seronegative participants without serious comorbid neurologic conditions that might impair neurocognitive performance, using linear regression and taking into account HIV-associated and demographic factors (including IV drug use) and liver function.

RESULTS

Neurocognitive performance characterized by global deficit scores and the proportion of individuals who were impaired were the same in the HCV-seropositive and HCV-seronegative groups. In univariable analyses in the entire sample, only verbal domain scores showed small statistically different superior performance in the HCV+ group that was not evident in multivariable analysis. In the subgroup without significant comorbidities, scores in all 7 domains of neurocognitive functioning did not differ by HCV serostatus. Among the HCV-seropositive participants, there was no association between neurocognitive performance and serum HCV RNA concentration.

CONCLUSION

In HIV-infected patients, HCV coinfection does not contribute to neurocognitive impairment, at least in the absence of substantial HCV-associated liver damage, which was not evident in our cohort.

Exosome-associated hepatitis C virus in cell cultures and patient plasma

Hepatitis C virus (HCV) infects its target cells in the form of cell-free viruses and through cell-cell contact. Here we report that HCV is associated with exosomes. Using highly purified exosomes and transmission electron microscopic imaging, we demonstrated that HCV occurred in both exosome-free and exosome-associated forms. Exosome-associated HCV was infectious and resistant to neutralization by an anti-HCV neutralizing antibody. There were more exosome-associated HCV than exosome-free HCV detected in the plasma of HCV-infected patients. These results suggest exosome-associated HCV as an alternative form for HCV infection and transmission.

Insights from interferon-α-related depression for the pathogenesis of depression associated with inflammation

Interferon-α (IFN-α) is a pleiotropic cytokine that is administered as a therapeutic in highly prevalent medical conditions such as chronic hepatitis C and B virus infection, melanoma and lymphoma. IFN-α induces, to a clinically relevant degree, concentration, memory, drive and mood disturbances in almost half of all patients. For this reason, IFN-α is increasingly being replaced by more specifically acting drugs. In the past decades, IFN-α has offered a valuable insight into the pathogenesis of major depression, particularly in settings associated with inflammation. IFN-α triggers immune responses, hypothalamo-pituitary-adrenal axis abnormalities and disturbances of brain metabolism resembling those in other depression states. IFN-α stimulates indoleamine-2,3 dioxygenase-1, activating the kynurenine pathway with reduced formation of the neurotransmitters serotonin and dopamine, excessive formation of the NMDA agonist quinolinic acid, and reduced formation of the NMDA antagonist kynurenic acid. In addition, IFN-α disturbs neurotrophic signaling and impedes neurite outgrowth, synaptic plasticity, endogenous neurogenesis and neuronal survival. Consequently, IFN-α-related depression may represent a model for the neurodegenerative changes that are noticed in late-life major depression. Indeed, the observation that brain responses in IFN-α-related depression resemble idiopathic depression is supported by the existence of common genetic signatures, among which of note, a number of neuronal survival and plasticity genes have been identified. In view of the high incidence of depressive symptoms, IFN-α-related depression is an attractive model for studying links between neuronal plasticity, neurodegeneration and depression. We predict that in the latter areas new targets for anti-depressant therapies could be identified, which may deepen our understanding of idiopathic major depression.

Persistent neurocognitive decline in a clinic sample of hepatitis C virus-infected persons receiving interferon and ribavirin treatment

Treatment of hepatitis C virus (HCV) with pegylated interferon and ribavirin (IFN/RBV) can be associated with neuropsychiatric side effects, which may necessitate dose reductions or treatment discontinuation. This study aimed to characterize the time course and predictors of cognitive and affective/mood symptoms after IFN/RBV treatment initiation. Forty individuals enrolled in a longitudinal project underwent comprehensive cognitive, medical, and psychiatric assessment at baseline and 10 weeks, 6 months, 12 months, and 18 months after treatment initiation. Analyses were conducted to determine the prevalence of neurocognitive impairment over time; explicate the relationship between neurocognitive impairment, neuropsychiatric symptoms, and liver disease at each time point; and identify predictors of neurocognitive decline as well as cognitive effects of viral clearance. By 10 weeks after initiating IFN/RBV, the prevalence of neurocognitive impairment rose from 22.5 to 47.4% (p < 0.05). Infection with genotype 1 and premorbid depression were associated with more severe declines (p < 0.05). After 18 months, 42.5% remained neurocognitively impaired, independent of viral clearance, severity of liver disease, and current depressive symptoms. Undetectable viral load was not associated with improvement 18 months after initiating treatment (p > 0.10). Results of the current study indicate that IFN/RBV treatment-emergent neurocognitive declines are significant, prevalent, and may persist long after treatment cessation. Clinicians should monitor cognition throughout the course of treatment for HCV, noting that early declines may indicate individuals at elevated risk for persistent neurocognitive impairment. Longer-term studies are needed to determine whether lasting declines may remit over longer intervals or with newer direct acting agents.

Depressive symptoms in chronic hepatitis C are associated with plasma apolipoprotein E deficiency

Neuro-psychiatric and cognitive disorders are frequent in patients with chronic hepatitis C (CHC) virus (HCV) infection which adversely impact quality of life, antiviral treatment adherence and outcome. HCV has neurotrophic properties and affects lipid metabolism, essential for cognitive function. We evaluated the relationship of lipid profiles with depression and anxiety symptoms and the effects of 12-weeks of therapy with fluvastatin and omega-3 ethyl esters (n-3 PUFA) in a randomised pilot study of CHC prior non-responders. Participants (n = 60) had fasting lipid profiles and assessment of depression and anxiety symptoms using the Hospital Anxiety and Depression Scale (HADS) questionnaire at each study visit. At screening 26/60 (43 %) had HADS-A score ≥8 and 13/60 (22 %) had HADS-D scores ≥8. Depressed patients had significantly lower apolipoprotein-E concentrations (30 mg/l vs 39 mg/l, P = 0.029) than those without depression and a tendency toward lower total cholesterol (3.8 vs 4.4 mmol/l, P = 0.053). 3 patients discontinued lipid-modifying treatment because of worsening depression. However, there was a small but significant improvement in anxiety symptoms after 12-weeks of high-dose (2-4 g daily) n-3 PUFA. In conclusion, depression in CHC is associated with plasma apoE deficiency. We postulate that apoE deficiency disrupts blood brain barrier integrity to promote HCV infection of the CNS. High-dose n-PUFAs may alleviate anxiety in some CHC patients but the use of lipid lowering therapy must be balanced against risks of worsening depression.

Iron homeostasis and its regulators over the course of chronic hepatitis C

ABSTRACT: 

Chronic infection with HCV has been diagnosed in approximately 170 million people worldwide. It is an important cause of chronic, progressive liver fibrosis. Late consequences of chronic HCV infection, including liver cirrhosis and hepatocellular carcinoma, have become the major indications for liver transplantation in developed countries. Particular attention is being paid to iron accumulation in chronic hepatitis C and its relation to the current antiviral therapy's efficacy and safety, risk of exacerbation of oxidative stress, development of metabolic disorders and hepatocarcinogenesis. HCV infection disrupts the synthesis of hepcidin, which regulates extracellular iron content. This article discusses the impact of iron on HCV multiplication and the involvement of impaired iron homeostasis in chronic hepatitis C in terms of the pathogenesis of insulin resistance, fatty liver and hepatocarcinogenesis.

Rapid Regulation of Depression-Associated Genes in a New Mouse Model Mimicking Interferon-α-Related Depression in Hepatitis C Virus Infection

Major depression is a serious side effect of interferon-α (IFN-α), which is used in the therapy of hepatitis C virus (HCV) infection. Due to the lack of reproducible animal models, the mechanisms underlying IFN-α-related depression are largely unknown. We herein established a mouse model, in which murine IFN-α (250 IU/day) and polyinosinic/polycytidylic acid (poly(I:C); 1 μg/day), a toll-like receptor-3 (TLR3) agonist that mimics the effect of HCV double-strand RNA, were continuously infused into the lateral ventricle via miniosmotic pumps over up to 14 days. The delivery of IFN-α and poly(I:C), but not of IFN-α or poly(I:C) alone, resulted in a reproducible depression-like state that was characterized by reduced exploration behavior in open-field tests, increased immobility in tail suspension and forced swimming tests, and a moderate loss of body weight. In the hippocampus and prefrontal cortex, the pro-inflammatory genes TNF-α, IL-6, tissue inhibitor of metalloproteinases-1 (Timp-1), CXC motif ligand-1 (Cxcl1), Cxcl10, and CC motif ligand-5 (Ccl5) were synergistically induced by IFN-α and poly(I:C), most pronounced after 14-day exposure. In comparison, the interferon-inducible genes of signal transducer and activator of transcription-1 (Stat1), guanylate binding protein-1 (Gbp1), proteasome subunit-β type-9 (Psmb9), ubiquitin-conjugating enzyme E2L-6 (Ube2l6), receptor transporter protein-4 (Rtp4), and GTP cyclohydrolase-1 (Gch1), which had previously been elevated in the blood of IFN-α-treated patients developing depression, in the brains of suicidal individuals, and in primary neurons exposed to IFN-α and poly(I:C), were induced even earlier, reaching maximum levels mostly after 24 hours. We propose that interferon-inducible genes might be useful markers of imminent depression.

New evidence of replication of hepatitis C virus in short-term peripheral blood mononuclear cell cultures

BACKGROUND

Even though hepatocytes are the main site for hepatitis C virus (HCV) replication, peripheral blood mononuclear cells (PBMC) have also been proposed as a suitable site for HCV replication. However, this issue still remains under discussion. We have previously developed an innovative system where HCV-RNA can be recovered during PBMC culture from HCV infected patients. Thus, the aim of this work was to use this novel approach in order to observe the evolution and replication of HCV genotype 1b in the PBMC of an HIV-HCV coinfected patient.

METHODS

HCV-RNA was extracted from serum, uncultured PBMC and PBMC culture at day 6, 20 and 33. The evolutionary analysis was performed using the direct sequences of three viral regions: 5'UTR, E2 and NS5A. Additionally, E2 region was cloned in order to extend the evolutive analysis.

RESULTS

In the present work, the molecular characterization of HCV along the culture showed a clear dynamic evolving process with the appearance of several nucleotide or amino acid changes in the three regions analyzed. Furthermore, the population analysis of E2 clones showed emerging and loss of lineages which indicate the fast evolutive dynamics of this system.

CONCLUSIONS

Since evolution can take place only if the virus is replicating in the culture, this finding constitutes an important evidence of viral replication in PBMC. Moreover, this extrahepatic compartment could be very important due to the presence of distinctive variants that could be responsible for resistance to treatment, viral pathogenesis and other clinical implications.

Vasculitis: determinants of disease patterns

The vasculitides are a large group of heterogeneous diseases for which it has been assumed that pathogenesis is largely autoimmune. As clinicians, we distinguish one form of vasculitis from another on the basis of observed patterns of organ injury, the size of the vessels affected and histopathological findings. The terms 'small-vessel', 'medium-vessel' and 'large-vessel' vasculitis are useful clinical descriptors, but fail to inform us about why vessels of a certain calibre are favoured by one disease and not another. Classification based on vessel size also fails to consider that vessels of a specific calibre are not equally prone to injury. Distinct vulnerabilities undoubtedly relate to the fact that same-size vessels in different tissues may not be identical conduits. In fact, vessels become specialized, from the earliest stages of embryonic development, to suit the needs of different anatomical locations. Vessels of the same calibre in different locations and organs are as different as the organ parenchymal cells through which they travel. The dialogue between developing vessels and the tissues they perfuse is designed to meet special local needs. Added to the story of vascular diversity and vulnerability are changes that occur during growth, development and ageing. An improved understanding of the unique territorial vulnerabilities of vessels could form the basis of new hypotheses for the aetiopathogenesis of the vasculitides. This Review considers how certain antigens, including infectious agents, might become disease-relevant and how vascular diversity could influence disease phenotypes and the spectrum of vascular inflammatory diseases.

Seronegative hepatitis C virus infection in patients with lymphoproliferative disorders

It has been reported that hepatitis C virus (HCV) RNA may be present in serum and/or lymphoid cells in the absence of specific circulating antibodies. The current study analysed seronegative HCV infection in patients with lymphoproliferative disorders. We studied 77 anti-HCV-negative patients (45 male and 32 female, mean age 54.8 ± 14.2 years) with various lymphoproliferative disorders. HCV-RNA was detected by RT-PCR in plasma, peripheral blood mononuclear cells (PBMC) and bone marrow. Furthermore, the presence of viral nonstructural protein 3 (NS3) was determined in PBMC and bone marrow by immunostaining. HCV-RNA was detectable in at least one compartment in 27 (35.1%) patients. Viral RNA was found in bone marrow in 22 patients (28.6%), in PBMC in 13 (16.9%) and in plasma in 10 (13%) patients. In nine patients, evidence of infection was confined to the bone marrow compartment. Viral load in HCV-RNA-positive plasma ranged from 15 to 1.17 × 10(3) IU/mL. NS3 was detected in all but two HCV-RNA-positive bone marrow samples and in all but one HCV-RNA-positive PBMC samples. All 27 HCV-RNA-positive patients remained anti-HCV-negative when tested again after 6-12 months, but only four remained HCV-RNA positive. In conclusion, among patients with lymphoproliferative disorders, HCV can be present in plasma, PBMC and bone marrow despite the lack of circulating specific antibodies. Further studies are required to analyse the phenomenon of seronegative infection and to determine whether such patients are infectious.

Flaviviruses are neurotropic, but how do they invade the CNS?

Flaviruses (FV) are RNA viruses carried by mosquitoes. Neurological signs including acute encephalitis, meningitis and acute flaccid paralysis develop in a small percentage of infected individuals; long term sequlae are, Parkinsonism, dystonias and cognitive changes. FV neuroinfection is neurotropic involving subcortical nuclei (substantia nigra and thalamus) anterior horn neurons and neocortex. Glycosylation of the FV E envelope protein is one determinant of neuroinvasion, increasing both axonal and trans-epithelial transportation. Neutralizing antibodies against the E and NS proteins prevents FV uptake into several cell types, including axons. CD8+ T cells are vital for clearance of WNF infected cells from the CNS, whereas TLR-3 and TLR-7 mediated anti-virus response through increased serum inflammatory cytokines to disrupt the BBB providing infected leucocytes and free virus access to the CNS (so called Trojan horse) Cellular virus attachment factors, promoting FV cell entry are widely distributed and include DC-SIGN (that detects complex carbohydrate molecules); Glycosamino glycans (GAG), Heparan sulphate(HSPG) Semaphorin 7A, Low Density Lipid receptors (LDLR); these are not FV specific virus entry receptors. The FV also crosses epithelial and endothelial barriers by disrupting Tight Junction complexes to increase BBB permeability. This review describes the multiple pathways responsible for the neuroinvasive properties of the Flaviviruses.

Hepatitis C virus (HCV) interaction with astrocytes: nonproductive infection and induction of IL-18

Hepatitis C virus (HCV) infection causes the central nervous system (CNS) abnormalities in more than 50 % of chronically infected subjects. However, the underlying mechanisms are largely unknown. In this study, we characterized the HCV interactions with astrocytes, one of the putative HCV target cells in the brain. We demonstrated that primary human astrocytes (PHA) were very inefficiently infected by HCV, either in the cell-free form or through cell-cell contact. We then determined the potential restriction steps of HCV infection and replication in these cells. PHA expressed all known HCV receptors but failed to support HCV entry. HCV IRES-mediated RNA translation was functional in PHA and further enhanced by miR122 expression. Nevertheless, PHA did not support HCV replication regardless of miR122 expression. To our great surprise, we found that HCV exposure induced robust IL-18 expression in PHA and exhibited direct neurotoxicity. Taken together, these results showed that astrocytes did not support productive HCV infection and replication, but HCV interactions with astrocytes and neurons alone might be sufficient to cause CNS dysfunction.

Visualizing hepatitis C virus infection in humanized mice

Hepatitis C virus (HCV) establishes frequently persistent infections. Chronic carriers can develop severe liver disease. HCV has been intensely studied in a variety of cell culture systems. However, commonly used cell lines and primary hepatocyte cultures do not or only in part recapitulate the intricate host environment HCV faces in the liver. HCV infects readily only humans and chimpanzees, which poses challenges in studying HCV infection in vivo. Consequently, tractable small animal models are needed that are not only suitable for analyzing HCV infection but also for testing novel therapeutics. Here, we will focus our discussion on humanized mice, i.e. mice engrafted with human tissues or expressing human genes, which support HCV infection. We will further highlight novel methods that can be used to unambiguously detect HCV infected cells in situ, thereby facilitating a spatio-temporal dissection of HCV infection in the three dimensional context of the liver.

Concomitant interferon alpha stimulation and TLR3 activation induces neuronal expression of depression-related genes that are elevated in the brain of suicidal persons

We have previously identified 15 genes that are associated with the development of severe depressive side effects during the standard therapy with interferon alpha and ribavirin in the peripheral blood of hepatitis C virus infected patients. An enhanced expression of these genes was also found in the blood of psychiatric patients suffering severe depressive episode. Herein, we demonstrate that the same depression-related interferon-inducible genes (DRIIs) are also upregulated in post-mortem brains of suicidal individuals. Using cultured mouse hippocampal and prefrontal neurons we show that costimulation with murine IFN (mIFN) and the TLR3 agonist poly(I:C) promotes the expression of the described DRIIs, at the same time inducing pro-inflammatory cytokine expression through Stat1 and Stat3 activation, promoting neuronal apoptosis. Consequently, the upregulation of selective DRIIs, production of inflammatory cytokines and inhibition of neuronal plasticity may be involved in the pathogenesis of IFN-associated depression.

Detection of hepatitis C virus (HCV) negative strand RNA and NS3 protein in peripheral blood mononuclear cells (PBMC): CD3+, CD14+ and CD19+

Background

Although hepatitis C virus (HCV) is primarily hepatotropic, markers of HCV replication were detected in peripheral blood mononuclear cells (PBMC) as well as in ex vivo collected tissues and organs. Specific strains of HCV were found to be capable to infect cells of the immune system: T and B cells and monocytes/macrophages as well as cell lines in vitro. The direct invasion of cells of the immune system by the virus may be responsible for extrahepatic consequences of HCV infection: cryoglobulinemia and non-Hodgkin’s lymphoma.

The aim of the present study was to determine the prevalence of markers of HCV infection: negative strand HCV RNA and non-structural NS3 protein in PBMC subpopulations: CD3⁺, CD14⁺ and CD19⁺. The presence of virus and the proportion of affected cells within a particular PBMC fraction could indicate a principal target cell susceptible for HCV.

Methods

PBMC samples were collected from 26 treatment-free patients chronically infected with HCV. PBMC subpopulations: CD3⁺, CD14⁺, CD19⁺ were obtained using positive magnetic separation. The presence of negative strand RNA HCV and viral NS3 protein were analyzed by strand-specific RT-PCR and NS3 immunocytochemistry staining.

Results

Negative strand HCV RNA was detectable in 7/26 (27%), whereas NS3 protein in 15/26 (57.6%) of PBMC samples. At least one replication marker was found in 13/26 (50%) of CD3⁺ cells then in 8/26 (30.8%) of CD14⁺ and CD19⁺ cells. The highest percentage of cells harboring viral markers in single specimen was also observed in CD3⁺ (2.4%), then in CD19⁺ (1.2%), and much lower in CD14⁺ (0.4%) cells.

Conclusions

Our results indicate that CD3⁺ cells are a dominant site for extrahepatic HCV replication, although other PBMC subpopulations may also support virus replication.

Dynamic changes in viral population structure and compartmentalization during chronic hepatitis C virus infection in children

Classic phylogenetic and modern population-based clustering methods were used to analyze hepatitis C virus (HCV) evolution in plasma and to assess viral compartmentalization within peripheral blood mononuclear cells (PBMCs) in 6 children during 3.2-9.6yr of follow-up. Population structure analysis of cloned amplicons encompassing hypervariable region 1 led to the distinction of two evolutionary patterns, one highly divergent and another one genetically homogeneous. Viral adaptability was reflected by co-evolution of viral communities switching rapidly from one to another in the context of divergence and stability associated with highly homogeneous communities which were replaced by new ones after long periods. Additionally, viral compartmentalization of HCV in PBMCs was statistically demonstrated, suggesting their role as a pool of genetic variability. Our results support the idea of a community-based structure of HCV viral populations during chronic infection and highlight a role of the PBMC compartment in the persistence of such structure.

Evaluation of early cerebral metabolic, perfusion and microstructural changes in HCV-positive patients: a pilot study

BACKGROUND & AIMS

The aim of the study was to evaluate early metabolic perfusion, and microstructural cerebral changes in patients with the hepatitis C virus (HCV) infection and normal appearing brain on plain MR using advanced MR techniques, as well as to assess correlations of MR measurements with the liver histology activity index (HAI).

METHODS

Fifteen HCV-positive patients and 18 control subjects underwent single voxel MR spectroscopy (MRS), perfusion weighted imaging (PWI), and diffusion tensor imaging (DTI), using a 1.5T MR unit. MRS metabolite ratios (NAA/Cr, Cho/Cr, mI/Cr) were calculated. PWI values of relative cerebral blood volume (rCBV) were assessed from 8 areas including several cortical locations, basal ganglia, and fronto-parietal white matter. DTI fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were obtained from 14 white matter tracts.

RESULTS

Compared to controls, HCV-positive patients showed significantly (p < 0.05) lower NAA/Cr ratios within frontal and parietal white matters, lower rCBV values within frontal and temporo-parietal cortices, decreased FA values, as well as increased ADC values in several white matter tracts. We also found elevated rCBV values in basal ganglia regions. The increase in mI/Cr and Cho/Cr ratio was correlated with a higher HAI score.

CONCLUSIONS

The results of advanced MR techniques indicate neurotoxicity of HCV reflected by neuronal impairment within white matter, cortical hypoperfusion, and disintegrity within several white matter tracts. Hyperperfusion in basal ganglia may be an indicator of brain inflammation in HCV patients. Our findings may suggest a biologic link between HCV-related liver disease and cerebral dysfunction.

Evaluation of hepatitis C virus as a risk factor for HIV-associated neuroretinal disorder

BACKGROUND

Both hepatitis C virus (HCV) and human immunodeficiency virus (HIV) penetrate the central nervous system. HIV-associated neuroretinal disorder (HIV-NRD), a visual impairment of reduced contrast sensitivity and reading ability, is associated with cytokine dysregulation and genetic polymorphisms in the anti-inflammatory interleukin 10 (IL-10) signaling pathway. We investigated associations between HCV and HIV-NRD and between HCV and single-nucleotide polymorphisms (SNPs) in the IL-10 receptor 1 (IL10R1) gene.

METHODS

Logistic and Cox regression analysis were used to analyze risk factors for HIV-NRD in 1576 HIV-positive patients who did not have an ocular opportunistic infection at enrollment. Median follow-up was 4.9 years (interquartile range, 2.4-8.8 years). Four IL10R1 SNPs were examined in a subset of 902 patients.

RESULTS

The group included 290 patients with chronic HCV infection, 74 with prior infection, and 1212 with no HCV markers. There were 244 prevalent cases of HIV-NRD and 263 incident cases (rate = 3.9/100 person-years). In models adjusted for demographics, HIV treatment and status, liver function, and immune status, both the prevalence and incidence of HIV-NRD were significantly higher in patients with chronic HCV infection (odds ratio = 1.54; 95% confidence interval [CI], 1.03-2.31 and hazard ratio = 1.62; 95% CI, 1.13-2.34, respectively), compared to patients with no HCV markers. Chronic HCV was associated with rs2228055 and 2 additional IL-10R1 SNPs expected to reduce IL-10 signaling. HIV-NRD was not significantly associated with these SNPs.

CONCLUSIONS

HCV is a possible risk factor for HIV-NRD. Genetic analysis suggests that alterations in the IL-10 signaling pathway may increase susceptibility to HIV-NRD and HCV infection. Inflammation may link HCV and HIV-NRD.

Significance of monoclonal antibodies against the conserved epitopes within non-structural protein 3 helicase of hepatitis C virus

Nonstructural protein 3 (NS3) of hepatitis C virus (HCV), codes for protease and helicase carrying NTPase enzymatic activities, plays a crucial role in viral replication and an ideal target for diagnosis, antiviral therapy and vaccine development. In this study, monoclonal antibodies (mAbs) to NS3 helicase were characterized by epitope mapping and biological function test. A total of 29 monoclonal antibodies were produced to the truncated NS3 helicase of HCV-1b (T1b-rNS3, aa1192–1459). Six mAbs recognized 8/29 16mer peptides, which contributed to identify 5 linear and 1 discontinuous putative epitope sequences. Seven mAbs reacted with HCV-2a JFH-1 infected Huh-7.5.1 cells by immunofluorescent staining, of which 2E12 and 3E5 strongly bound to the exposed linear epitope ¹²³¹PTGSGKSTK¹²³⁹ (EP05) or core motif ¹³⁷³IPFYGKAI¹³⁸⁰ (EP21), respectively. Five other mAbs recognized semi-conformational or conformational epitopes of HCV helicase. MAb 2E12 binds to epitope EP05 at the ATP binding site of motif I in domain 1, while mAb 3E5 reacts with epitope EP21 close to helicase nucleotide binding region of domain 2. Epitope EP05 is totally conserved and EP21 highly conserved across HCV genotypes. These two epitope peptides reacted strongly with 59–79% chronic and weakly with 30–58% resolved HCV infected blood donors, suggesting that these epitopes were dominant in HCV infection. MAb 2E12 inhibited 50% of unwinding activity of NS3 helicase in vitro. Novel monoclonal antibodies recognize highly conserved epitopes at crucial functional sites within NS3 helicase, which may become important antibodies for diagnosis and antiviral therapy in chronic HCV infection.

Differential expression of candidate virus receptors in human T lymphocytes prone or resistant to infection with patient-derived hepatitis C virus

Accumulated evidence implies that hepatitis C virus (HCV) infects not only the liver but also the immune system. A lymphocyte-specific CD5 molecule was recently identified as essential for infection of T cells with native, patient-derived HCV. To assess whether the proposed hepatocyte receptors may also contribute to HCV lymphotropism, expression of scavenger receptor-class B type 1 (SR-B1), claudin-1 (CLDN-1), claudin-6 (CLDN-6), occludin (OCLN), CD5 and CD81 was examined by real-time RT-PCR and the respective proteins quantified by immunoblotting in HCV-prone and resistant T cell lines, peripheral blood mononuclear cells (PBMC), primary T cells and their subsets, and compared to hepatoma Huh7.5 and HepG2 cells. SR-B1 protein was found in T and hepatoma cell lines but not in PBMC or primary T lymphocytes, CLDN-1 in HCV-resistant PM1 T cell line and hepatoma cells only, while CLDN-6 equally in the cells investigated. OCLN protein occurred in HCV-susceptible Molt4 and Jurkat T cells and its traces in primary T cells, but not in PBMC. CD5 was displayed by HCV-prone T cell lines, primary T cells and PBMC, but not by non-susceptible T and hepatoma cell lines, while CD81 in all cell types except HepG2. Knocking-down OCLN in virus-prone T cell line inhibited HCV infection, while de novo infection downregulated OCLN and CD81, and upregulated CD5 without modifying SR-B1 expression. Overall, while no association between SR-B1, CLDN-1 or CLDN-6 and the susceptibility to HCV was found, CD5 and CD81 expression coincided with virus lymphotropism and that of OCLN with permissiveness of T cell lines but unlikely primary T cells. This study narrowed the range of factors potentially utilized by HCV to infect T lymphocytes amongst those uncovered using laboratory HCV and Huh7.5 cells. Together with the demonstrated role for CD5 in HCV lymphotropism, the findings indicate that virus utilizes different molecules to enter hepatocytes and lymphocytes.