Clinicopathologic correlates of hepatitis C virus in brain: a pilot study

Is there a connection between neurocognitive profile in treatment naïve non-cirrhotic HCV patients and level of systemic inflammation?

Hepatitis C virus (HCV) infection is a progressive, systemic disease which leads to the development of end-stage liver disease. In 70% of patients, HCV infection is followed by the development of extrahepatic manifestations (EHM). A common EHM is HCV associated neurocognitive disorder (HCV-AND), characterized by neuropsychological changes in attention, working memory, psychomotor speed, executive function, verbal learning, and recall. The aim of this study is to examine the correlation between the neurocognitive profile and routine, available laboratory parameters of inflammation, liver function tests, grade of liver fibrosis, and clinical and laboratory parameters of mixed cryoglobulinemia in treatment naïve non-cirrhotic HCV patients. This is a single-center exploratory study in which we examined 38 HCV + treatment naïve patients. The complete blood count and hematological parameters of systemic inflammation, liver function tests, biopsy confirmed grade of liver fibrosis, and clinical and laboratory parameters of mixed cryoglobulinemia caused by chronic HCV infection were observed. In the study, we used a battery of neuropsychological tests assessing multiple cognitive domains: executive functions, verbal fluency, delayed memory, working memory and learning, and one measure for visuo-constructive performance. Before the Bonferroni correction for multiple comparisons, the results show significant correlations between the scores in the neurocognitive variables and the single measures of inflammation, liver function parameters, and mixed cryoglobulinemia. It has not found a statistically significant correlation between systemic inflammation and neurocognitive variables. After the Bonferroni adjustment, no correlations remained significant. Certainly, the obtained results can be a recommendation for additional validation through future research.

Hepatitis C Virus-Related Central and Peripheral Nervous System Disorders

Hepatitis C Virus (HCV), despite being a hepatotropic virus, is the causative agent of many systemic disorders, such as vasculitis, autoimmune diseases, lymphoproliferative disorders, and a broad spectrum of neurological and psychiatric manifestations. Although symptoms have been misdiagnosed or underdiagnosed, only recently, evidence of direct (inflammatory) or indirect (immune-mediated) HCV-dependent cerebral effects has been established. HCV infection can promote acute inflammatory response, pro-coagulative status and ischemic disorders, and neurodegeneration. These effects rely on cerebral HCV replication, possibly mediated by blood-brain barrier alterations. Further study is needed to better understand the HCV-related mechanisms of brain damage.

Depression, fatigue and neurocognitive deficits in chronic hepatitis C

Patients with chronic hepatitis C virus (HCV) infection experience a range of symptoms including depression, fatigue and neurocognitive deficits, impairing quality of life. Depression, in particular, may be reactive to increased psychosocial stress, and the physical symptoms of advanced HCV or associated comorbidities. However, even patients at an early stage of HCV infection, with minimal hepatic inflammation or comorbidities, report more depressive symptoms and fatigue than the general population. Similarly, specific neurocognitive deficits occur in early stage HCV infection and are independent of the presence of depression or encephalopathy. Therefore, intracerebral neurobiological changes associated with HCV may potentially explain these symptoms. These changes may arise from infiltration of the brain by peripherally induced cytokines, as well as direct neuropathic effects of HCV viral particles penetrating the blood-brain barrier. These phenomena parallel those reported in human immunodeficiency virus (HIV) infection. HCV-associated intracerebral changes include upregulated inflammatory responses, altered neurotransmitter levels, hormonal dysregulation, and release of neurotoxic substances. These may subsequently lead to abnormal neuronal conduction and function in areas of the brain governing affective responses, emotional processing, motivation, attention and concentration. Although direct-acting antiviral medications lead to high rates of HCV clearance, intracerebral changes may not be subsequently reversed and symptoms of depression, fatigue and neurocognitive deficits may persist. There is an ongoing role for multidisciplinary care and pharmacotherapy to manage these symptoms in HCV patients. Furthermore, there may be opportunities for future therapies to specifically target and ameliorate HCV-associated intracerebral changes.

Psychiatric and functional neuroimaging abnormalities in chronic hepatitis C virus patients: Is vasculitis a contributing factor?

BACKGROUND AND STUDY AIMS

Central nervous system (CNS) involvement in hepatitis C virus (HCV) infection has different facets such as anxiety, depression, cognitive impairment and vasculitis. We were interested in detecting subclinical CNS involvement in chronic HCV infected subjects with and without systemic vasculitis.

PATIENTS AND METHODS

Nineteen patients (15 females and 4 males) with chronic HCV infection (mean age 46.5 ± 7 and mean duration since diagnosis of HCV infection 4.7 ± 4 years, including 6 (32%) Child-Pugh class A cirrhotic patients) and 30 age, sex and education matched healthy control subjects were studied. Thirteen patients had associated vasculitis. Patients and control subjects were assessed using the block design and comprehension subtests of Wechsler Bellevue Adult Intelligence Scale, Wechsler Memory scale (WMS), Beck Anxiety Inventory (BAI) and Beck Depression Inventory (BDI). Brain HMPAO Single Photon Emission Computed Tomography (SPECT) was performed for HCV patients.

RESULTS

Patients with HCV had lower scores on the block design test compared to control subjects (8.37 ± 1.89 versus 10.37 ± 1.47, p < 0.001), lower total WMS scores (43.15 ± 10.49 versus 60.27 ± 8.08, p < 0.001) and higher anxiety and depression scores (16.94 ± 10.46 and 37.17 ± 10.38 versus 10.3 ± 4.67 and 28.9 ± 5.99, p = 0.004 and 0.001, respectively). Total WMS were lower in HCV patients with vasculitis compared to those without vasculitis (39.14 ± 9.3 versus 51.17 ± 8.3, p = 0.019) while the block design and comprehension tests, BAI and BDI were not significantly different between both groups. The block design and comprehension tests, WMS, BAI and BDI were not significantly different between cirrhotic and non-cirrhotic patients. Seven patients had different patterns of cerebral hypoperfusion on SPECT, and all of them had associated vasculitis. Abnormal SPECT was associated with lower total WMS scores (35.87 ± 10.8 versus 46.79 ± 8.6 in those with normal SPECT, p = 0.049).

CONCLUSIONS

Vasculitis may contribute to the development of neuropsychiatric involvement in HCV patients.

Neurocognitive impairment with hepatitis C and HIV co-infection in Southern Brazil

Although cognitive impairment has been well documented in human immunodeficiency virus (HIV) and hepatitis C virus (HCV) mono-infections, research on neurocognitive effects is limited in the context of HIV/HCV co-infection. The aims of this study were to explore the interplay between HIV and HCV infections in the expression of neurocognitive impairment (NCI), and to examine the differences in test performance between HIV/HCV co-infected and HIV or HCV mono-infected patients. A total of 128 participants from Southern Brazil underwent a comprehensive neuropsychological (NP) battery comprising 18 tests. Participants were grouped according to their serological status: HCV mono-infected (n = 20), HIV mono-infected (n = 48), HIV/HCV co-infected (n = 12), and HIV-/HCV-uninfected controls (n = 48). The frequencies of HIV subtypes B and C between the HIV mono-infected and HIV/HCV co-infected groups were comparable. There was greater prevalence of neuropsychological impairment among all three infection groups compared with the uninfected control group, but no statistically significant differences among mono- and co-infected groups were found. HCV infection was associated with cognitive deficits, independently of liver dysfunction. HCV infection did not show an additive effect on neurocognitive function among HIV+. NCI was independent of HCV RNA on peripheral blood, CSF, and hepatic injury. While we did not find additive global effect, in the present study, there was some evidence of additive HIV/HCV co-infection effects in speed of information processing, executive function, and verbal fluency domains when comparing the co-infected group with the other three groups. NP impairment was not dependent on HCV subtypes.

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.

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.

The impact of human immune deficiency virus and hepatitis C coinfection on white matter microstructural integrity

The purpose of the present study is to examine the integrity of white matter microstructure among individuals coinfected with HIV and HCV using diffusion tensor imaging (DTI). Twenty-five HIV+ patients, 21 HIV+/HCV+ patients, and 25 HIV- controls were included in this study. All HIV+ individuals were stable on combination antiretroviral therapy (cART; ≥3 months). All participants completed MRI and neuropsychological measures. Clinical variables including liver function, HIV-viral load, and CD4 count were collected from the patient groups. DTI metrics including mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD), and fractional anisotropy (FA) from five subregions of the corpus callosum were compared across groups. The HIV+/HCV+ group and HIV+ group were similar in terms of HIV clinical variables. None of the participants met criteria for cirrhosis or fibrosis. Within the anterior corpus callosum, significant differences were observed between both HIV+ groups compared to HIV- controls on DTI measures. HIV+ and HIV+/HCV+ groups had significantly lower FA values and higher MD and RD values compared to HIV- controls; however, no differences were present between the HIV+ and HIV+/HCV+ groups. Duration of HIV infection was significantly related to DTI metrics in total corpus callosum FA only, but not other markers of HIV disease burden or neurocognitive function. Both HIV+ and HIV+/HCV+ individuals had significant alterations in white matter integrity within the corpus callosum; however, there was no evidence for an additive effect of HCV coinfection. The association between DTI metrics and duration of HIV infection suggests that HIV may continue to negatively impact white matter integrity even in well-controlled disease.

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.

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.

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.

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.

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.

Cell culture systems for hepatitis C virus

Due to the obligatory intracellular lifestyle of viruses, cell culture systems for efficient viral propagation are crucial to obtain a detailed understanding of the virus-host cell interaction. For hepatitis C virus (HCV) the development of permissive and authentic culture models continues to be a challenging task. The first efforts to culture HCV had limited success and range back to before the virus was molecularly cloned in 1989. Since then several major breakthroughs have gradually overcome limitations in culturing the virus and sequentially permitted analysis of viral RNA replication, cell entry, and ultimately the complete replication cycle in cultured cells in 2005. Until today, basic and applied HCV research greatly benefit from these tremendous efforts which spurred multiple complementary cell-based model systems for distinct steps of the HCV replication cycle. When used in combination they now permit deep insights into the fascinating biology of HCV and its interplay with the host cell. In fact, drug development has been much facilitated and our understanding of the molecular determinants of HCV replication has grown in parallel to these advances. Building on this groundwork and further refining our cellular models to better mimic the architecture, polarization and differentiation of natural hepatocytes should reveal novel unique aspects of HCV replication. Ultimately, models to culture primary HCV isolates across all genotypes may teach us important new lessons about viral functional adaptations that have evolved in exchange with its human host and that may explain the variable natural course of hepatitis C.

HCV-related nervous system disorders

Chronic infection with hepatitis C virus (HCV) is associated with a wide spectrum of extrahepatic manifestations, affecting different organ systems. Neurological complications occur in a large number of patients and range from peripheral neuropathy to cognitive impairment. Pathogenetic mechanisms responsible for nervous system dysfunction are mainly related to the upregulation of the host immune response with production of autoantibodies, immune complexes, and cryoglobulins. Alternative mechanisms include possible extrahepatic replication of HCV in neural tissues and the effects of circulating inflammatory cytokines and chemokines.

Acute HCV/HIV coinfection is associated with cognitive dysfunction and cerebral metabolite disturbance, but not increased microglial cell activation

BACKGROUND

Microglial cell activation and cerebral function impairment are described in both chronic hepatitis C viral (HCV) and Human-Immune-Deficiency viral (HIV) infections. The aim of this study was to investigate the effect of acute HCV infection upon cerebral function and microglial cell activation in HIV-infected individuals.

METHODS

A case-control study was conducted. Subjects with acute HCV and chronic HIV coinfection (aHCV) were compared to matched controls with chronic HIV monoinfection (HIVmono). aHCV was defined as a new positive plasma HCV RNA within 12 months of a negative RNA test. Subjects underwent neuro-cognitive testing (NCT), cerebral proton magnetic resonance spectroscopy ((1)H-MRS) and positron emission tomography (PET) using a (11)C-radiolabeled ligand (PK11195), which is highly specific for translocator protein 18 kDA receptors on activated microglial cells. Differences between cases and controls were assessed using linear regression modelling.

RESULTS

Twenty-four aHCV cases completed NCT and (1)H-MRS, 8 underwent PET. Of 57 HIVmono controls completing NCT, 12 underwent (1)H-MRS and 8 PET. Subjects with aHCV demonstrated on NCT, significantly poorer executive function (mean (SD) error rate 26.50(17.87) versus 19.09(8.12), p = 0.001) and on (1)H-MRS increased myo-inositol/creatine ratios (mI/Cr, a marker of cerebral inflammation) in the basal ganglia (ratio of 0.71(0.22) versus 0.55(0.23), p = 0.03), compared to subjects with HIVmono. On PET imaging, no difference in (11)C-PK11195 binding potential (BP) was observed between study groups (p>0.10 all cerebral locations), however lower BPs were associated with combination antiretroviral therapy (cART) use in the parietal (p = 0.01) and frontal (p = 0.03) cerebral locations.

DISCUSSION

Poorer cognitive performance and disturbance of cerebral metabolites are observed in subjects with aHC,V compared to subjects with HIVmono. Higher (11)C-PK11195 BP was not observed in subjects with aHCV, but was observed in subjects not on cART.

Hepatitis C virus and the brain

Hepatitis C virus (HCV) is an enveloped, positive-strand RNA virus of the family Flaviviridae that primarily infects hepatocytes, causing acute and chronic liver disease. HCV is also associated with a variety of extrahepatic symptoms including central nervous system (CNS) abnormalities, cognitive dysfunction, fatigue and depression. These symptoms do not correlate with the severity of liver disease and are independent of hepatic encephalopathy. HCV RNA has been associated with CNS tissue, and reports of viral sequence diversity between brain and liver tissue suggest independent viral evolution in the CNS and liver. This review will explore the data supporting HCV infection of the CNS and how this fits into our current understanding of HCV pathogenesis.

Neurobehavioral effects of interferon-α in patients with hepatitis-C: symptom dimensions and responsiveness to paroxetine

In patients at high risk for recurrence of malignant melanoma, interferon-α (IFN-α), a stimulator of innate immunity, appears to induce distinct neurobehavioral symptom dimensions: a mood and anxiety syndrome, and a neurovegetative syndrome, of which the former is responsive to prophylactic administration of paroxetine. We sought to determine whether symptom dimensions (and treatment responsiveness) arise in patients with hepatitis C administered IFN-α and ribavirin. In a randomized, double-blind, 6-month study, 61 patients with hepatitis C eligible for therapy with IFN-α and ribavirin received the antidepressant paroxetine (n=28) or a placebo (n=33). Study medication began 2 weeks before IFN-α/ribavirin therapy. Neuropsychiatric assessments included the 10-item Montgomery-Asberg Depression Rating Scale (MADRS). The items of the MADRS were grouped into depression, anxiety, cognitive dysfunction, and neurovegetative symptom dimensions, and analyzed using a mixed model. By 2 weeks of IFN-α/ribavirin therapy, all four dimensions increased, with the symptom dimensions of anxiety and cognitive dysfunction fluctuating and worsening, respectively, in both groups over time. The depression symptom dimension was significantly lower in the paroxetine treatment group (p=0.04); severity of the neurovegetative symptom dimension was similar in both groups. Similar to patients with malignant melanoma receiving high-dose IFN-α, the depression symptom dimension is more responsive to paroxetine treatment in individuals undergoing concomitant IFN-α/ribavirin therapy. However, the anxiety, cognitive dysfunction, and neurovegetative symptom dimensions appear less responsive to prophylactic paroxetine administration. Different neurobiologic pathways may contribute to the responsiveness of IFN-α-induced symptom dimensions to antidepressant treatment, requiring relevant psychopharmacologic strategies.

Effects of hepatitis C and HIV on cognition in women: data from the Women's Interagency HIV Study

OBJECTIVE

To compare neuropsychological scores in women infected with HIV, women infected with both HIV and hepatitis C, and uninfected subjects.

BACKGROUND

Some, but not all, studies have demonstrated that dual infection with Hepatitis C virus (HCV) and HIV has worse effects on cognition than infection with HIV alone.

DESIGN/METHODS

The Women's Interagency HIV Study is an ongoing prospective study of the natural history of HIV in women where participants are reevaluated every 6 months. In a cross-sectional analysis, we evaluated the effects of active HIV and HCV infections on scores on symbol-digit modalities test, the Stroop interference test, and trails A and B after controlling for age, ethnicity, education, depression, liver disease, and current or past substance abuse.

RESULTS

Data were available for 1338 women-17.8 % had detectable hepatitis C virus and 67% were HIV seropositive. In fully adjusted general linear models, HCV viremia was not associated with scores on any of the cognitive tests.

CONCLUSIONS

In this large sample of women, active HCV infection was not associated with scores on a small battery of neuropsychological tests.

Hepatitis C virus entry: beyond receptors

HCV is a blood-borne pathogen that affects approximately 3% of the global population and leads to progressive liver disease. Recent advances have identified an essential role for host cell molecules: tetraspanin CD81, scavenger receptor B1 and the tight junction proteins claudin-1 and occludin in HCV entry, suggesting a complex multi-step process. The conserved nature of this receptor-dependent step in the viral life cycle offers an attractive target for therapeutic intervention. Evidence is emerging that additional factors other than classical receptors, such as inflammatory mediators regulate the ability of hepatocytes to support HCV entry, and as such may provide potential avenues for drug design and development. In this review, we summarise the recent literature on HCV entry mechanisms with a view to realising the future potential of therapeutically targeting this process.

Hepatitis C virus infects the endothelial cells of the blood-brain barrier

BACKGROUND & AIMS

Hepatitis C virus (HCV) infection leads to progressive liver disease and is associated with a variety of extrahepatic syndromes, including central nervous system (CNS) abnormalities. However, it is unclear whether such cognitive abnormalities are a function of systemic disease, impaired hepatic function, or virus infection of the CNS.

METHODS

We measured levels of HCV RNA and expression of the viral entry receptor in brain tissue samples from 10 infected individuals (and 3 uninfected individuals, as controls) and human brain microvascular endothelial cells by using quantitative polymerase chain reaction and immunochemical and confocal imaging analyses. HCV pseudoparticles and cell culture-derived HCV were used to study the ability of endothelial cells to support viral entry and replication.

RESULTS

Using quantitative polymerase chain reaction, we detected HCV RNA in brain tissue of infected individuals at significantly lower levels than in liver samples. Brain microvascular endothelia and brain endothelial cells expressed all of the recognized HCV entry receptors. Two independently derived brain endothelial cell lines, hCMEC/D3 and HBMEC, supported HCV entry and replication. These processes were inhibited by antibodies against the entry factors CD81, scavenger receptor BI, and claudin-1; by interferon; and by reagents that inhibit NS3 protease and NS5B polymerase. HCV infection promotes endothelial permeability and cellular apoptosis.

CONCLUSIONS

Human brain endothelial cells express functional receptors that support HCV entry and replication. Virus infection of the CNS might lead to HCV-associated neuropathologies.

Effects of anti-viral therapy and HCV clearance on cerebral metabolism and cognition

BACKGROUND & AIMS

Chronic hepatitis C virus (HCV) infection is associated with altered cerebral metabolism and cognitive dysfunction. We aimed to evaluate the effect of pegylated interferon/ribavirin (PIFN/R) and HCV clearance on cerebral metabolism, and neuropsychological performance.

METHODS

Fifteen non-cirrhotic HCV positive subjects underwent (1)H MR spectroscopy (MRS) before, during, and after treatment with PIFN/R. The metabolites of interest namely, N-acetylaspartate (NAA), choline (Cho), myo-inositol (MI), and the control metabolite creatine (Cr), were acquired from 3 different brain regions; left basal ganglia, left frontal cortex, and left dorso-lateral pre-frontal cortex. Coinciding with this, subjects also underwent a battery of neuropsychological tests to evaluate the domains of verbal learning, memory, attention, language, executive functioning, and motor skills. Seven HCV positive controls (not receiving anti-viral therapy) underwent MRS and neuropsychological testing at two time points, 12 weeks apart, to examine for variation in cerebral metabolites over time and the practice effect of repeat neuropsychological testing.

RESULTS

Significant reductions in basal ganglia Cho/Cr (p=0.03) and basal ganglia MI/Cr (p=0.03) were observed in sustained virological responders (SVRs, n=8), but not non-responders/relapsers (NR/R, n=6), indicative of reduced cerebral infection and/or immune activation in those who cleared virus. SVRs demonstrated significant improvements in verbal learning, memory, and visuo-spatial memory. A small but significant improvement in neurocognitive function secondary to the practice effect was seen in both HCV controls and HCV subjects during treatment.

CONCLUSIONS

HCV eradication has a beneficial effect on cerebral metabolism and selective aspects of neurocognitive function and is an important factor when contemplating anti-viral therapy in HCV, especially in those with mild disease.

Neuropsychological alterations in hepatitis C infection: The role of inflammation

About 50% of patients with hepatitis C virus (HCV) infection complain of neuropsychiatric symptoms, “brain fog”, weakness, fatigue, and exhibit some degree of quality of life impairment, irrespective of the severity of liver disease. Since the first observation of HCV-related cognitive deficits, 10 studies have been published that have evaluated neuropsychiatric performance in patients with HCV infection and different degrees of hepatic impairment. Unfortunately, these have often included patients with cirrhosis, patients who had acquired the infection through previous intravenous drug misuse, who had a history of relatively recent treatment with interferon, or were on psychoactive medication. In addition, different neuropsychological batteries and tests that explored different cognitive domains were used, which makes the results of the studies difficult to compare. Finally, limited information is available on the pathogenesis of HCV-related cognitive impairment. Cerebral and/or systemic inflammation may be important players but their potential role has not been substantiated by experimental data. The present review outlines the available evidence of the presence of cognitive impairment in patients with HCV infection, with a focus on the potential relationship with cerebral and/or systemic inflammation.

Hepatitis C virus enters human peripheral neuroblastoma cells - evidence for extra-hepatic cells sustaining hepatitis C virus penetration

Patients with chronic hepatitis C virus (HCV) infection show an increased incidence of nervous system disorders such as chronic fatigue syndrome, depression and cognitive dysfunction. It is unclear whether this is because of HCV replication in the brain and in peripheral neuronal cells or to more indirect effects of HCV infection on the central or peripheral nervous system. The aim of this study was to investigate whether cells originating from these tissues are permissive for HCV cell entry, RNA replication and virus assembly. Among eight cell lines analysed, the human peripheral neuroblastoma cell line SKNMC expressed all HCV entry factors and was efficiently infected with HCV pseudoparticles (HCVpp) independent of the HCV genotype. All remaining cell types including human neuroblastoma and glioblastoma cell lines and microglial cells lacked expression of at least one host factor essential for HCV entry. When transfected with HCV luciferase reporter virus RNA, inoculated with HCV reporter viruses or challenged with high-titre cell culture-derived HCV, none of these cells supported detectable HCV RNA replication. Thus, in conclusion, this comprehensive screening did not reveal evidence directly strengthening the notion that HCV enters and replicates in the central nervous system. However, productive viral entry into the peripheral neuroblastoma cell line SKNMC indicates that HCV may penetrate into certain nonhepatic cell types which may serve as viral reservoirs and could modulate viral pathogenesis.

Human cell types important for hepatitis C virus replication in vivo and in vitro: old assertions and current evidence

Hepatitis C Virus (HCV) is a single stranded RNA virus which produces negative strand RNA as a replicative intermediate. We analyzed 75 RT-PCR studies that tested for negative strand HCV RNA in liver and other human tissues. 85% of the studies that investigated extrahepatic replication of HCV found one or more samples positive for replicative RNA. Studies using in situ hybridization, immunofluorescence, immunohistochemistry, and quasispecies analysis also demonstrated the presence of replicating HCV in various extrahepatic human tissues, and provide evidence that HCV replicates in macrophages, B cells, T cells, and other extrahepatic tissues. We also analyzed both short term and long term in vitro systems used to culture HCV. These systems vary in their purposes and methods, but long term culturing of HCV in B cells, T cells, and other cell types has been used to analyze replication. It is therefore now possible to study HIV-HCV co-infections and HCV replication in vitro.

Hepatitis C virus core protein induces neuroimmune activation and potentiates Human Immunodeficiency Virus-1 neurotoxicity

Background

Hepatitis C virus (HCV) genomes and proteins are present in human brain tissues although the impact of HIV/HCV co-infection on neuropathogenesis remains unclear. Herein, we investigate HCV infectivity and effects on neuronal survival and neuroinflammation in conjunction with HIV infection.

Methodology

Human microglia, astrocyte and neuron cultures were infected with cell culture-derived HCV or exposed to HCV core protein with or without HIV-1 infection or HIV-1 Viral Protein R (Vpr) exposure. Host immune gene expression and cell viability were measured. Patch-clamp studies of human neurons were performed in the presence or absence of HCV core protein. Neurobehavioral performance and neuropathology were examined in HIV-1 Vpr-transgenic mice in which stereotaxic intrastriatal implants of HCV core protein were performed.

Principal Findings

HCV-encoded RNA as well as HCV core and non-structural 3 (NS3) proteins were detectable in human microglia and astrocytes infected with HCV. HCV core protein exposure induced expression of pro-inflammatory cytokines including interleukin-1β, interleukin-6 and tumor necrosis factor-α in microglia (p<0.05) but not in astrocytes while increased chemokine (e.g. CXCL10 and interleukin-8) expression was observed in both microglia and astrocytes (p<0.05). HCV core protein modulated neuronal membrane currents and reduced both β-III-tubulin and lipidated LC3-II expression (p<0.05). Neurons exposed to supernatants from HCV core-activated microglia exhibited reduced β-III-tubulin expression (p<0.05). HCV core protein neurotoxicity and interleukin-6 induction were potentiated by HIV-1 Vpr protein (p<0.05). HIV-1 Vpr transgenic mice implanted with HCV core protein showed gliosis, reduced neuronal counts together with diminished LC3 immunoreactivity. HCV core-implanted animals displayed neurobehavioral deficits at days 7 and 14 post-implantation (p<0.05).

Conclusions

HCV core protein exposure caused neuronal injury through suppression of neuronal autophagy in addition to neuroimmune activation. The additive neurotoxic effects of HCV- and HIV-encoded proteins highlight extrahepatic mechanisms by which HCV infection worsens the disease course of HIV infection.

Brain dysfunction in the era of combination antiretroviral therapy: implications for the treatment of the aging population of HIV-infected individuals

Improvements in the treatment of HIV infection and in the advancement of combination antiretroviral therapy (cART) have led to an increase in the number of individuals with HIV who are surviving to an older age. Preventing the development of neurocognitive abnormalities has become an increasingly important issue in this aging patient population, which is already at risk for cognitive impairment as a result of the neuropathological effects of HIV. cART has been critical in reducing the overall severity of HIV-associated neurocognitive disorders (HAND), but numerous challenges remain, as the prevalence of HAND continues to be high. There are several key areas in which treatment could be improved to reduce the incidence and severity of HAND. The use of well-tolerated cART medications that are able to penetrate the blood-brain barrier hold particular promise, as these agents may enable increased viral suppression in the parenchyma and may reduce neurocognitive dysfunction. In addition, the improved treatment of comorbid medical conditions that are common in patient populations with HIV (eg, HCV, liver failure and metabolic syndrome) is critical, as several of these conditions are known to have a significant effect on neural functions. Various research approaches indicate that the development of agents that control free radicals, neurotoxicity, proinflammatory processes and apoptosis may also have substantial potential in this field.

Cognitive function does not worsen during long-term low-dose peginterferon therapy in patients with chronic hepatitis C

OBJECTIVES

Neuropsychiatric toxicity is a common dose-limiting side effect of interferon therapy. The primary aim of this study was to determine whether patients receiving long-term low-dose peginterferon therapy had a higher incidence of cognitive side effects compared with untreated patients enrolled in the Hepatitis C Antiviral Long-Term treatment against Cirrhosis (HALT-C) Trial.

METHODS

A total of 129 patients with chronic hepatitis C and advanced fibrosis completed a battery of 10 neuropsychological tests and the Beck Depression Inventory at pretreatment baseline and at months 12, 24, 36, and 48 while receiving long-term peginterferonalpha2a (90 microg/week) or no therapy during the randomized phase of the HALT-C Trial. Cognitive impairment was defined as a global deficit score (GDS) > or = 1.0.

RESULTS

The mean age was 51.2 years, 67% were male, and 42% had cirrhosis. After accounting for baseline GDS scores, the mean GDS scores did not significantly change over time (P=0.46) nor with treatment group (P=0.49). Cognitive function was also not influenced by medication adherence in the 66 patients receiving maintenance peginterferon (P=0.14) after controlling for baseline GDS scores and time. Beck Depression scores did not significantly increase over time (P=0.60), nor did they vary by treatment group (P=0.74). Although 32% of patients experienced objective worsening of their liver disease during follow-up, the frequency and severity of cognitive impairment did not differ in those with and without disease progression (P=0.71).

CONCLUSIONS

Measures of cognitive function were neither influenced by low-dose peginterferon treatment nor with objective evidence of liver disease progression in patients with advanced chronic hepatitis C prospectively followed up for 3.5 years.

A neuropsychological study comparing patients infected with HCV and HBV without psychiatric comorbidities

Hepatitis C is one of the most common chronic infectious diseases worldwide, with well-documented extra-hepatic manifestations, such as a broad number of cognitive deficits. These impairments may be explained by psychiatric comorbidities, which have not been investigated properly in the literature. In order to elucidate a specific hepatitis C virus (HCV) induced cognitive impairment not related to mental disorders, neuropsychological performance of patients infected with HCV was compared with that of patients infected with hepatitis B virus cognitive impairment, especially psychiatric comorbidities. A total of 33 patients infected with HCV and 22 patients infected with HBV were included in the study. There were no significant differences between the two groups with regard to age or years of education. The group of patients infected with HCV performed significantly worse on visuo-spatial memory tasks after adjusting for years of education and age. There were no significant differences between patients infected with HCV and patients infected with HBV with regards to other neuropsychological functions. The data indicate that patients infected with HCV patients have poorer visuo-spatial memory performance than patients infected with HBV, suggesting that the cognitive deficit may be specific to HCV infection and not to secondary comorbid psychiatric disorders.

Psychiatric and substance use disorders comorbidities in veterans with hepatitis C virus and HIV coinfection

PURPOSE OF REVIEW

A growing number of veterans in the Veterans Health Administration are coinfected with HIV and hepatitis C virus. This review covers timely research relative to comorbid conditions that are common in this population including psychiatric diagnoses, substance use disorders and neurocognitive problems.

RECENT FINDINGS

Current literature on the psychiatric, substance use disorders and cognitive problems of the coinfected population show that not only are rates of morbidity higher in the coinfected population but that this affects antiviral treatments as well. There is new evidence that brain injuries and infiltration of the virus into the central nervous system may be responsible for cognitive dysfunction. Cotesting, particularly in hepatitis C infected individuals, is not done routinely despite shared risk factors.

SUMMARY

With this understanding of the comorbidities of the coinfected population, integrated healthcare models involving mental health, internal medicine, substance abuse treatment and internal medicine are crucial to work with these medically and psychologically complex patients.

Drug abuse and hepatitis C infection as comorbid features of HIV associated neurocognitive disorder: neurocognitive and neuroimaging features

Substance abuse and co-infection with hepatitis C (HCV) are two highly relevant determinants of neurocognitive and neuroimaging abnormalities associated with HIV. Substance abuse and HCV are common in the HIV population and there is increasing evidence that the CNS is directly compromised by these comorbid conditions via additive or synergistic processes. In this article we review the current literature regarding mechanisms of neuronal injury as well as the neuropsychological and neuroimaging signatures associated with substance abuse and HCV status among HIV patients. We discuss specific methodological challenges and threats to validity associated with studies of HIV and comorbid substance use disorders or HCV and review potential strategies for minimizing their confounding effects. Efforts to understand the interactions between HIV, substance abuse and HCV co-infection will lead to more complete models of neuropathogenesis of HIV and a greater understanding of the variability in neuropsychological expression of HIV Associated Neurocognitive Disorder.

Hepatitis C virus neuroinvasion: identification of infected cells

Hepatitis C virus (HCV) infection often is associated with cognitive dysfunction and depression. HCV sequences and replicative forms were detected in autopsy brain tissue and cerebrospinal fluid from infected patients, suggesting direct neuroinvasion. However, the phenotype of cells harboring HCV in brain remains unclear. We studied autopsy brain tissue from 12 HCV-infected patients, 6 of whom were coinfected with human immunodeficiency virus. Cryostat sections of frontal cortex and subcortical white matter were stained with monoclonal antibodies specific for microglia/macrophages (CD68), oligodendrocytes (2',3'-cyclic nucleotide 3'-phosphodiesterase), astrocytes (glial fibrillary acidic protein [GFAP]), and neurons (neuronal-specific nuclear protein); separated by laser capture microscopy (LCM); and tested for the presence of positive- and negative-strand HCV RNA. Sections also were stained with antibodies to viral nonstructural protein 3 (NS3), separated by LCM, and phenotyped by real-time PCR. Finally, sections were double stained with antibodies specific for the cell phenotype and HCV NS3. HCV RNA was detected in CD68-positive cells in eight patients, and negative-strand HCV RNA, which is a viral replicative form, was found in three of these patients. HCV RNA also was found in astrocytes from three patients, but negative-strand RNA was not detected in these cells. In double immunostaining, 83 to 95% of cells positive for HCV NS3 also were CD68 positive, while 4 to 29% were GFAP positive. NS3-positive cells were negative for neuron and oligodendrocyte phenotypic markers. In conclusion, HCV infects brain microglia/macrophages and, to a lesser extent, astrocytes. Our findings could explain the biological basis of neurocognitive abnormalities in HCV infection.

Molecular and bioinformatic evidence of hepatitis C virus evolution in brain

BACKGROUND

Neurocognitive deficits in patients with hepatitis C virus (HCV) infection prompted a search for HCV in brain.

RESULTS

HCV was present in the brains of 7 (54%) of 13 patients with viremia, as determined by 5' UTR and E1 (envelope 1) gene analysis. Brain HCV RNA consensus sequences differed from those in plasma and liver in 4 (57%) of 7 patients. The quality of HCV RNA from postmortem brain and liver was assessed and demonstrated to be suitable for sequence analysis. Quasispecies analysis revealed that several mutations present in clones from >1 brain region were absent in clones from liver and plasma. Brain-specific mutations defined several families of related sequences. The patterns of brain-specific mutations in these families were consistent with the evolution of HCV RNA from a common ancestor. Single-nucleotide-polymorphism analysis confirmed that a prominent brain-specific mutation constituted approximately 10% of HCV RNA in cerebellum and medulla but that this mutation was undetectable in the liver and plasma of the same patient.

CONCLUSIONS

This study introduces novel methods for assessing RNA from postmortem samples. It increases the reported cases of HCV in the brain, provides the first E1 sequences from the brain, and contributes to the growing evidence that HCV replicates and evolves within the brain.