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

Long-Term Follow-Up of Neuropsychiatric Symptoms After Sustained Virological Response to Interferon-Free and Interferon-Based Hepatitis C Virus Treatment

Chronic hepatitis C virus (HCV) infection can be associated with neuropsychiatric symptoms like fatigue and cognitive impairment, independent of the liver status. The present study aims to assess changes in the pattern and extent of neuropsychological symptoms after successful treatment with interferon (IFN)-based and IFN-free therapy. HCV-infected patients who underwent neuropsychological assessment in previous studies were invited to a follow-up examination. Patients were grouped according to the treatment status: Sustained virological response (SVR) after IFN treatment (IFN SVR, n = 14) or after therapy with direct acting antivirals (DAA SVR, n = 28) or ongoing HCV infection (HCV RNA+, n = 11). A group of 33 healthy controls served as reference. Patients completed self-report questionnaires addressing health-related quality of life (HRQoL), mood and sleep quality and a neuropsychological test battery including tests of memory and attention (Luria's list of words, PSE test, cancelling "d" test, Word-Figure-Memory Test and computer-based test battery for the assessment of attention [TAP]). At baseline, all three patient groups had worse fatigue, depression, anxiety and HRQoL scores compared to healthy controls. Longitudinal analysis revealed that fatigue and mood slightly improved in all patient groups over time, while HRQoL improved in SVR patients but not in HCV RNA+ patients. Memory test results improved significantly in all patient groups, irrespective of their virological status. In contrast, the attention test results showed no clear change from baseline to follow-up. Our data can be considered as a hint that HCV eradication-independent of therapy regimen-does not substantially ameliorate neuropsychiatric symptoms in HCV-afflicted patients.

From Viral Infections to Alzheimer's Disease: Unveiling the Mechanistic Links Through Systems Bioinformatics

BACKGROUND

Emerging evidence suggests that viral infections may contribute to Alzheimer's disease (AD) onset and/or progression. However, the extent of their involvement and the mechanisms through which specific viruses increase AD susceptibility risk remain elusive.

METHODS

We used an integrative systems bioinformatics approach to identify viral-mediated pathogenic mechanisms, by which Herpes Simplex Virus 1 (HSV-1), Human Cytomegalovirus (HCMV), Epstein-Barr virus (EBV), Kaposi Sarcoma-associated Herpesvirus (KSHV), Hepatitis B Virus (HBV), Hepatitis C Virus (HCV), Influenza A Virus (IAV) and Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) could facilitate AD pathogenesis via virus-host protein-protein interactions (PPIs). We also explored potential synergistic pathogenic effects resulting from herpesvirus reactivation (HSV-1, HCMV, and EBV) during acute SARS-CoV-2 infection, potentially increasing AD susceptibility.

RESULTS

Herpesviridae members (HSV-1, EBV, KSHV, HCMV) impact AD-related processes like amyloid-β (Aβ) formation, neuronal death, and autophagy. Hepatitis viruses (HBV, HCV) influence processes crucial for cellular homeostasis and dysfunction, they also affect microglia activation via virus-host PPIs. Reactivation of HCMV during SARS-CoV-2 infection could potentially foster a lethal interplay of neurodegeneration, via synergistic pathogenic effects on AD-related processes like response to unfolded protein, regulation of autophagy, response to oxidative stress, and Aβ formation.

CONCLUSIONS

These findings underscore the complex link between viral infections and AD development. Viruses impact AD-related processes through shared and distinct mechanisms, potentially influencing variations in AD susceptibility.

Peripheral inflammation is a potential etiological factor in Alzheimer's disease

Peripheral inflammation could constitute a risk factor for AD. This review summarizes the research related to peripheral inflammation that appears to have a relationship with Alzheimer's disease. We find there are significant associations between AD and peripheral infection induced by various pathogens, including herpes simplex virus type 1, cytomegalovirus, Epstein-Barr virus, human immunodeficiency virus, severe acute respiratory syndrome coronavirus 2, Porphyromonas gingivalis, Helicobacter pylori, and Toxoplasma gondii. Chronic inflammatory diseases are also reported to contribute to the pathophysiology of AD. The mechanisms by which peripheral inflammation affects the pathophysiology of AD are complex. Pathogen-derived neurotoxic molecule composition, disrupted BBB, and dysfunctional neurogenesis may all play a role in peripheral inflammation, promoting the development of AD. Anti-pathogenic medications and anti-inflammatory treatments are reported to decrease the risk of AD. Studies that could improve understanding the associations between AD and peripheral inflammation are needed. If our assumption is correct, early intervention against inflammation may be a potential method of preventing and treating AD.

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.

Regulation of mild cognitive impairment associated with liver disease by humoral factors derived from the gastrointestinal tract and MRI research progress: a literature review

Patients with liver disease are prone to various cognitive impairments. It is undeniable that cognitive impairment is often regulated by both the nervous system and the immune system. In this review our research focused on the regulation of mild cognitive impairment associated with liver disease by humoral factors derived from the gastrointestinal tract, and revealed that its mechanisms may be involved with hyperammonemia, neuroinflammation, brain energy and neurotransmitter metabolic disorders, and liver-derived factors. In addition, we share the emerging research progress in magnetic resonance imaging techniques of the brain during mild cognitive impairment associated with liver disease, in order to provide ideas for the prevention and treatment of mild cognitive impairment in liver disease.

Morphological changes in the brain in liver cirrhosis of alcoholic and viral etiology

Background. Hepatic encephalopathy is an actual problem of modern medicine. However, its pathogenesis and histological picture are currently insufficiently studied. Less is known about the impact of the nature of primary liver disease on pathogenesis and histological picture of hepatic encephalopathy. This determines the relevance of further morphological studies of the brain in the late stages of liver cirrhosis of various etiologies.The aim. To establish and compare the morphological changes in the brain in alcoholic liver cirrhosis and viral (hepatitis C virus (HCV)) cirrhosis.Materials and methods. The morphological study of the brain of 40 deceased in outcome of HCV-associated cirrhosis and 23 patients died in outcome of chronic alcoholism was carried out. Histological changes in various parts of the brain were studied using survey and elective stains. The immunohistochemical study of HCV NS3 and CD68 expression in different brain regions was performed in cases of HCV-infection.Results. The changes of neurons, glial cells and cerebral microvessels underlie in the basis of morphological picture of brain damage in both studied groups underlie that corresponds to the “classical” model of hepatic encephalopathy pathogenesis. At the same time, a number of morphological features were observed. The most prominent differences concerned the manifestations of the glial reaction. The productive changes of macroglial cells with the appearance of multiple Alzheimer’s astrocytes type 2 as well as spongious changes in subcortical white matter dominated in the observations of alcoholic cirrhosis. In contrast, microglia cells reaction (microgliosis) in white matter was noticed in HCV-associated cirrhosis.Conclusions. The differences in histological signs of brain in the terminal stages of liver disease of viral and alcoholic etiology are shown. They broaden current idea of morphological picture of hepatic encephalopathy, and may be used to study its pathogenesis.

Status Epilepticus in Post-Transplantation Hyperammonemia Involves Careful Metabolic Management

Hyperammonemia is a condition that may result after solid organ transplantation, particularly lung transplantation. However, it is very uncommon for this presentation to occur more than 30 days post-transplantation. Hyperammonemia and the resulting encephalopathy typically manifest with altered sensorium, a clinical situation which is not often included in the differential diagnosis of presumed nonconvulsive status epilepticus (NCSE). Seizures are common among this subset of patients with hyperammonemia and may be refractory to traditional treatments. Evidence of elevated intracranial pressure by invasive monitoring and neuroimaging findings of diffuse cerebral edema are commonly reported. Here we examine the therapeutic importance of identifying the specific cause of hyperammonemic encephalopathy, a condition which may result in status epilepticus and ultimately cerebral edema or even brain death.

Brain metabolic and microstructural alterations associated with hepatitis C virus infection, autoimmune hepatitis and primary biliary cholangitis

BACKGROUND AND AIMS

Neuropsychiatric symptoms in hepatitis C (HCV) patients resemble those of patients with autoimmune hepatitis (AIH) or primary biliary cholangitis (PBC), whilst the mechanisms behind them are unknown. Here we looked for cerebral metabolic and/or microstructural alterations in patients with HCV, AIH or PBC as possible causes behind these symptoms.

METHODS

Patients with HCV infection (n = 17), AIH (n = 14) or PBC (n = 11) and age-adjusted healthy controls (n = 18) underwent brain magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS) and psychometric assessment of memory and attention. Brain relative proton density (PD) and T2 relaxation time (T2) were determined in 17 regions of interest (ROIs), as were the concentrations of N-acetyl-aspartate, choline, creatine, myo-inositol and glutamine + glutamate in frontal- (fWM) and parietal white matter (pWM). One-way analysis of variance and Kruskal-Wallis tests were used for group comparison. Correlations between altered neuropsychological findings and MRI/MRS observations were estimated with the Spearman ρ test.

RESULTS

HCV, AIH and PBC patients revealed similar alterations in brain PD and metabolites compared to controls: significantly decreased PD in 7/17 ROIs in the HCV group, 16/17 ROIs in the PBC group and 14/17 ROIs in the AIH group, significantly increased N-acetyl-aspartate in fWM in all patients, significantly increased choline in the PBC group in both fWM and pWM, in the AIH group only in pWM and with a trend in the HCV group in pWM. Correlation analysis did not reveal significant associations between MRI/MRS alterations and neuropsychological dysfunction.

CONCLUSION

The findings suggest similar pathophysiological mechanisms behind neuropsychiatric symptoms associated with HCV infection, AIH and PBC.

Reduced microglia activity in patients with long-term immunosuppressive therapy after liver transplantation

PURPOSE

Calcineurin inhibitors (CNI) can cause long-term impairment of brain function. Possible pathomechanisms include alterations of the cerebral immune system. This study used positron emission tomography (PET) imaging with the translocator protein (TSPO) ligand 18F-GE-180 to evaluate microglial activation in liver-transplanted patients under different regimens of immunosuppression.

METHODS

PET was performed in 22 liver-transplanted patients (3 CNI free, 9 with low-dose CNI, 10 with standard-dose CNI immunosuppression) and 9 healthy controls. The total distribution volume (VT) estimated in 12 volumes-of-interest was analyzed regarding TSPO genotype, CNI therapy, and cognitive performance.

RESULTS

In controls, VT was about 80% higher in high affinity binders (n = 5) compared to mixed affinity binders (n = 3). Mean VT corrected for TSPO genotype was significantly lower in patients compared to controls, especially in patients in whom CNI dose had been reduced because of nephrotoxic side effect.

CONCLUSION

Our results provide evidence of chronic suppression of microglial activity in liver-transplanted patients under CNI therapy especially in patients with high sensitivity to CNI toxicity.

Have (R)-[11C]PK11195 challengers fulfilled the promise? A scoping review of clinical TSPO PET studies

PURPOSE

The prototypical TSPO radiotracer (R)-[11C]PK11195 has been used in humans for more than thirty years to visualize neuroinflammation in several pathologies. Alternative radiotracers have been developed to improve signal-to-noise ratio and started to be tested clinically in 2008. Here we examined the scientific value of these "(R)-[11C]PK11195 challengers" in clinical research to determine if they could supersede (R)-[11C]PK11195.

METHODS

A systematic MEDLINE (PubMed) search was performed (up to end of year 2020) to extract publications reporting TSPO PET in patients with identified pathologies, excluding studies in healthy subjects and methodological studies.

RESULTS

Of the 288 publications selected, 152 used 13 challengers, and 142 used (R)-[11C]PK11195. Over the last 20 years, the number of (R)-[11C]PK11195 studies remained stable (6 ± 3 per year), but was surpassed by the total number of challenger studies for the last 6 years. In total, 3914 patients underwent a TSPO PET scan, and 47% (1851 patients) received (R)-[11C]PK11195. The 2 main challengers were [11C]PBR28 (24%-938 patients) and [18F]FEPPA (11%-429 patients). Only one-in-ten patients (11%-447) underwent 2 TSPO scans, among whom 40 (1%) were scanned with 2 different TSPO radiotracers.

CONCLUSIONS

Generally, challengers confirmed disease-specific initial (R)-[11C]PK11195 findings. However, while their better signal-to-noise ratio seems particularly useful in diseases with moderate and widespread neuroinflammation, most challengers present an allelic-dependent (Ala147Thr polymorphism) TSPO binding and genetic stratification is hindering their clinical implementation. As new challengers, insensitive to TSPO human polymorphism, are about to enter clinical evaluation, we propose this systematic review to be regularly updated (living review).

A Review on Extrahepatic Manifestations of Chronic Hepatitis C Virus Infection and the Impact of Direct-Acting Antiviral Therapy

Extrahepatic manifestations are a feature of chronic hepatitis C virus (HCV) infection. In the course of chronic HCV infection, about 70% of patients have one or more extrahepatic manifestations. The latter are often the first and only clinical sign of infection. Experimental and clinical data support a causal association for many extrahepatic manifestations and HCV infection, which include mixed cryoglobulinemia, non-Hodgkin lymphomas (NHL), cardiovascular disease, insulin resistance, type 2 diabetes, neurological and psychiatric disease and other rheumatic diseases. All these extrahepatic conditions influence the morbidity, quality of life and mortality of HCV-infected patients. Currently, interferon-free therapeutic regimens with direct-acting antiviral agents (DAA) offer the possibility of treatment to almost the entire infected population, irrespective of stage of cirrhosis and associated serious comorbidities, always maintaining a high efficacy and tolerability. Several studies have shown a close association between HCV clearance by DAAs and an improvement or reduction in the risk of extrahepatic manifestations. Patients with HCV after a sustained virologic response (SVR) by DAA treatment have a lower risk than non-responders of developing cryoglobulinemic vasculitis and B-cell non-Hodgkin’s lymphomas. Furthermore, the SVR by DAA also reduces the risk of acute coronary syndrome, cardiovascular disease, insulin resistance and type 2 diabetes, and it improves atherosclerosis. HCV clearance by DAA also improves the quality of life and survival of patients with chronic HCV infection with associated extrahepatic diseases. Thus, DAAs should be initiated as early as possible in HCV patients with extrahepatic manifestations.

Impact of direct acting antivirals (DAA) on neurologic disorders in chronic hepatitis C

INTRODUCTION

Neurologic and neuropsychiatric manifestations sometimes provide the first evidence of an unknown HCV infection. These conditions develop with a variable ranging of morbidity, including: "brain fog," fatigue, subtle cognitive and attention impairment, but also with more severe complications or acute presentation, like encephalomyelitis, encephalopathy, stroke and peripheral nerves involvement.

EVIDENCE ACQUISITION

We performed a systematic literature search on PubMed, Cochrane Library and Web of Science databases for articles only in English language, that assessed the relationship between "DAA treatment and neurologic disorders" and after the attainment of SVR in full reports of cases that received the DAA schedule from January 2015 to December 2019. The following terms were used: "chronic Hepatitis C," "HCV," "DAA," "direct-acting antiviral," "SVR," "sustained virologic response," peripheral neuropathy" and "neurologic diseases or disorders."

EVIDENCE SYNTHESIS

HCV infection does not only involve the liver, causing cirrhosis and hepatocellular carcinoma (HCC), but also induces extrahepatic manifestations (EHM), mainly due to a complex immune disease, that damage small and medium vessels, called "mixed cryoglobulinemic vasculitis" (MCV). This kind of mechanism generates most of the HCV-induced neurological damages. Since 2015, the availability of direct-acting antiviral (DAA) oral molecules interfering with HCV replication has completely revolutionized therapeutic options and the target population, which now includes patients aged 12 to 80 years and with advanced liver disease. Relevant was the highlighted DAA effectiveness by achievement of a sustained virologic response (SVR) in about 95% of cases, showing a great tolerability.

CONCLUSIONS

This favorable effect has arisen in a wide category of patients infected by HCV, including subjects with cirrhosis and complications and/or with EHM, who showed a significant improvement of their symptoms and the disease regression. In this concise review, we examine the clinical outcomes after the introduction of the DAA for the treatment of chronic hepatitis C (CHC), focusing on the neurologic disorders and concluding that there is a strong amelioration of neurologic conditions in several cases, particularly, after attaining the viral eradication with a favorable course in most treated cases.

Cognitive, neurological and psychiatric disorders occurring in Hepatitis C Virus infection

Chronic Hepatitis C is associated with many extrahepatic manifestations. Central nervous system is frequently involved, but the pathophysiological mechanisms are not fully understood. Local and systemic inflammation, ischemia, immune-mediated phenomena have been described in this context. Clinical manifestations include cognitive alterations, stroke, depression and demyelinating phenomena. It is unclear if cognitive deficits can be improved or resolved with viral eradication and to understand this, could have important therapeutical implications.

[Hepatitis C in a psychiatric setting: A forgotten reservoir?]

Hepatitis C is a transmissible hepatic and extra-hepatic disease caused by the hepatitis C virus (HCV). HCV develops into a chronic infection among approximately 70% of the contaminated subjects. Chronic HCV infection is estimated to affect between 0.5% and 1 % of the general population in France, which causes an important burden of disease, in particular due to the occurrence of cirrhosis and liver cancer. New antiviral drugs now allow to cure more than 95% of patients in just a few weeks of treatment with very limited safety issues. This therapeutic revolution has led the World Health Organization and many national governments to aim for an elimination of HCV, which has been defined as a 90%-reduction of the incidence rate, and a 65%-reduction in the number of HCV-related deaths on the basis of the 2015 figures. In this respect, the French Ministry of Health has recently decided to extend the ability to prescribe the new antiviral drugs to any physician. However, the elimination campaign of HCV will also need to correctly identify, screen, and treat the main target populations. If people who inject drugs (PWIDs) certainly constitute the most important population concerned by the challenge of HCV elimination, more hidden reservoirs in which HCV transmission can insidiously evolve should be identified and specifically targeted as well. Inpatient psychiatric populations might constitute one of these hidden reservoirs. International data suggest that chronic HCV infection affects approximately 5% of psychiatric inpatients in Europe. This very high prevalence estimate can in part be due to the very frequent psychiatric disorders found among the current or former PWIDs. However, a part of the seropositive patients does not report a history of drug use, and other factors could contribute to the increased risk of contamination in this population including atypical routes of transmission related to institutional promiscuity. Exploring the general profile and risk-behaviors of the psychiatric inpatients found infected by the HCV is thus warranted for future studies. Screening and treating HCV in the specific population of psychiatric patients is part of the general public health objective of eliminating HCV at a national level. Moreover, it also directly fits into the individualized psychiatric care. Many recent data suggest that HCV also has a neural tropism, in particular within glial cells, such as astrocytes or oligodendrocytes. As such, HCV foments inflammatory processes in the brain and contributes to cognitive impairments and psychiatric symptoms such as anxiety or depression. At the individual level, treating HCV infection can improve the psychiatric state and increase patients' outcomes in terms of well-being and quality of life. For all these reasons, the field of psychiatry needs local and national actions for informing and training professionals about HCV screening and treating modalities. Patient and family associations also need to be involved in this general effort of micro-elimination. A key role should be assigned to the general practitioners embedded within inpatient psychiatric units. They are the best fitted professionals to screen, treat, and empower patients, to inform and train other caregivers of the psychiatric field, and to act as a relay with hepatology teams if required. Hospital pharmacists are other important stakeholders. In a national context in which the funding of psychiatric care, including medications, is based on predefined funding envelops, innovative initiatives will have to be set up by local or national health authorities, in partnership with pharmacists, to allow for the treatment of psychiatric inpatients. In conclusion, the world of psychiatry is a possible hidden reservoir of HCV and, as such, a part of the challenge for eliminating the virus. Patients, families, and caregivers will have to be correctly sensitized and trained to play their role in the process. Specific investigations will be required to better understand why such an increased prevalence of HCV is observed in this population. Specific adaptations of the cascade of care within psychiatric settings, including access to treatment, will need to be designed, implemented, and evaluated for reaching micro-elimination of HCV in psychiatry.

Neuroimaging Findings in Chronic Hepatitis C Virus Infection: Correlation with Neurocognitive and Neuropsychiatric Manifestations

Chronic hepatitis C virus (HCV) infection is commonly associated with neurocognitive dysfunction, altered neuropsychological performance and neuropsychiatric symptoms. Quantifiable neuropsychological changes in sustained attention, working memory, executive function, verbal learning and recall are the hallmark of HCV-associated neurocognitive disorder (HCV-AND). This constellation is at variance with the neuropsychological complex that is seen in minimal hepatic encephalopathy, which is typified by an array of alterations in psychomotor speed, selective attention and visuo-constructive function. Noncognitive symptoms, including sleep disturbances, depression, anxiety and fatigue, which are less easily quantifiable, are frequently encountered and can dominate the clinical picture and the clinical course of patients with chronic HCV infection. More recently, an increased vulnerability to Parkinson’s disease among HCV-infected patients has also been reported. The degree to which neurocognitive and neuropsychiatric changes are due to HCV replication within brain tissues or HCV-triggered peripheral immune activation remain to be determined. Without absolute evidence that clearly exonerates or indicts HCV, our understanding of the so-called “HCV brain syndrome”, relies primarily on clinical and neuropsychological assessments, although other comorbidities and substance abuse may impact on neurocognitive function, thus confounding an appropriate recognition. In recent years, a number of functional and structural brain imaging studies have been of help in recognizing possible biological markers of HCV-AND, thus providing a rationale for guiding and justifying antiviral therapy in selected cases. Here, we review clinical, neuroradiological, and therapeutic responses to interferon-based and interferon-free regimens in HCV-related cognitive and neuropsychiatric disorder.

Neuropsychiatric symptoms in hepatitis C patients resemble those of patients with autoimmune liver disease but are different from those in hepatitis B patients

Chronic fatigue, mood alterations and cognitive impairment are frequent accessory symptoms of HCV infection. Fatigue and mood alterations have also been observed in autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC), but not in hepatitis B virus (HBV)-infection, thus indicating an autoimmune response as possible cause of HCV infection-associated encephalopathy. Data, however, are sparse. This study aimed to prove that HCV patients feature similar to those with autoimmune liver disease but contrary to HBV patients regarding neuropsychiatric symptoms. A total of 132 noncirrhotic patients (HCV: 46, HBV: 22, AIH: 27, PBC: 29, AIH/PBC: 8) completed questionnaires addressing the domains mentioned above. Eighty-eight underwent a comprehensive neuropsychological assessment. Patient groups were compared among each other and to 33 healthy controls. Fatigue, anxiety and depression scores were significantly increased, and the SF-36 mental score significantly decreased in all patient groups compared to controls. Fatigue was significantly more pronounced in HCV than in HBV patients. HCV patients scored significantly worse than HBV patients but not AIH and PBC patients in the SF-36. HCV, AIH and PBC but not HBV patients did significantly worse than controls in word learning. Recognition of words was impaired in HCV, AIH and PBC patients and recognition of figures in HCV patients, exclusively (P ≤ 0.002). HCV patients did also worse than controls and HBV patients concerning alertness and working memory (P ≤ 0.001). The neuropsychiatric profiles of HCV patients are similar to those of AIH and PBC patients but differ from those of HBV patients, suggesting an autoimmune response as a possible cause for these differences.

Review article: unanswered clinical and research questions in autoimmune hepatitis-conclusions of the International Autoimmune Hepatitis Group Research Workshop

BACKGROUND

Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease that results in substantial morbidity and mortality with many unanswered clinical and research questions. Improved understanding of disease pathogenesis, including the extra-hepatic manifestations of AIH, may allow targeted treatments with greater efficacy and fewer associated adverse events.

AIM

To identify the spectrum of unanswered clinical and research questions facing care providers in the management of patients with autoimmune hepatitis (AIH).

METHODS

The International Autoimmune Hepatitis Group initiated a series of research workshops to start to address these questions. Key issues were discussed in small group sessions with collation of all discussions to be summarised in this manuscript.

RESULTS

Key issues were identified as: the need for better understanding of disease pathogenesis, standardisation of the methods and assays used to evaluate autoantibodies in AIH, refinement of the histopathological criteria for "typical" or "compatible" AIH, focus on the interaction with non-alcohol related fatty liver disease, how to treat acute severe AIH, better assessment of quality of life in adults and paediatrics, standardising use of standard, third-line and experimental therapies in AIH and search for biomarkers early in the disease course that predict outcome.

CONCLUSION

This workshop has outlined the key unanswered clinical and research questions to help to define the research agenda in AIH.

Neurological Complications Occurring After Liver Transplantation: Role of Risk Factors, Hepatic Encephalopathy, and Acute (on Chronic) Brain Injury

Orthotopic liver transplantation (LT) remains the only way to definitively cure patients with the most severe liver diseases. Because the survival rate is now fairly high, important questions about neurological sequelae or quality of life after LT have emerged. Indeed, LT represents a peculiar situation because up to 30% of patients present with neurological symptoms after LT compared with only 4% after cardiac transplant and 0.5% after renal transplant. These postoperative neurological symptoms have long been interpreted as sequelae of hepatic encephalopathy (HE). However, postoperative decompensation of an unknown cerebral condition due to the pathophysiology of cirrhosis or undiagnosed neurodegenerative disorders or aging constitute other possibilities that are underrecognized. Some patients who undergo LT for acute liver failure and patients with cirrhosis without episodes of HE and without any previous cerebral alteration also display post-LT neurological symptoms. This latter situation speaks in favor of a direct adverse effect of either general anesthesia, the surgical procedure, or factors related to the postoperative intensive care unit (ICU) environment. The role of inflammation, which has been described in the ICU setting, could also be a crucial determinant. In this review, we will discuss the neurological complications associated with LT, the neurocognitive complications after LT, and how to assess the LT-related neurological or neurocognitive complications. Furthermore, we will review the various hypotheses surrounding post-LT neurocognitive impairment and will conclude with recommendations for future directions.

Evaluation of brain volume alterations in HCV-infected patients after interferon-free therapy: A pilot study

The study was performed to evaluate cerebral volume changes in HCV-infected subjects before and after interferon-free therapy with direct-acting antiviral agents (DAA). We aimed also to estimate the impact of successful DAA therapy on the neuropsychological state of patients. Eleven HCV genotype 1 (GT1) patients treated with ombitasvir/paritaprevir (boosted with ritonavir) and dasabuvir, with or without ribavirin underwent brain magnetic resonance (MR) before and 24 weeks after completion of therapy. All patients achieved sustained viral response. Precise automatic parcellation was made using the fully-available software FreeSurfer 6.0. Statistically significant volume deceleration six months after treatment was found in the subcallosal cingulate gyrus, transverse frontopolar gyri and sulci, anterior segment of the circular sulcus of the insula and horizontal ramus of the anterior segment of the lateral sulcus. After DAA therapy we found statistically significant improvement in the performance of all three tasks of the Rey Complex Figure Test that permits the evaluation of different functions (attention, planning, working,memory). Additionally, significant amelioration in Percentage Conceptual Level Responses in The Wisconsin Card Sorting Test (a neurocognitive test for assessing intellectual functioning) was also discovered. Successful interferon-free therapy may lead to transient cerebral atrophy, probably by reducing neuroinflammation and oedema. This is the first pilot study of the alterations in brain volume after successful interferon-free therapy in chronic HCV patients. Longitudinal follow-up study is needed to observe further effects of therapy on cerebral structures volume changes.

Cerebral patterns of neuropsychological disturbances in hepatitis C patients

Neuropsychiatric symptoms and cognitive impairment have been consistently reported in patients with hepatitis C virus (HCV) infection. Since the mechanisms behind remain to be established, the present study attempted to assess whether neuropsychological impairments in HCV-infected patients are accompanied by structural alterations in the brain. Therefore, 19 anti-HCV-antibody-positive women with mild liver disease and 16 healthy controls underwent extensive neuropsychological testing and cranial magnetic resonance imaging (MRI) examination. Nine of the patients and five controls were followed up after 6-7 years. Voxel-based morphometry and magnetization transfer imaging were utilized to study HCV-associated structural gray and white matter changes. The HCV-infected patients had significantly worse fatigue and depression scores and significantly poorer performance on attention and memory tests than controls. The patients displayed gray matter (GM) atrophy in the bilateral insula and thalamus and a profound GM volume increases in the cerebellum. Microstructural GM changes in the insula were also evident by a reduced magnetization transfer ratio. Structural white matter changes were observed along several descending and crossing fiber tracts. Follow-up at 7 years revealed increased GM atrophy in the left amygdala and left parahippocampal regions over time. We conclude that our data provide evidence for structural alterations in the brains of patients with chronic HCV infection. Disturbances of cerebellothalamocortical regions and circuits, linking cerebellar projections to the prefrontal cortex through the thalamus, underpin the emotional and cognitive dysfunction characteristically observed in these patients.

Functional MRI and delay discounting in patients infected with hepatitis C

Hepatitis C virus-infected (HCV+) adults evidence increased rates of psychiatric and cognitive difficulties. This is the first study to use functional magnetic resonance imaging (fMRI) to examine brain activation in untreated HCV+ adults. To determine whether, relative to non-infected controls (CTLs), HCV+ adults exhibit differences in brain activation during a delay discounting task (DDT), a measure of one's tendency to choose smaller immediate rewards over larger delayed rewards-one aspect of impulsivity. Twenty adults with HCV and 26 CTLs completed an fMRI protocol during the DDT. Mixed effects regression analyses of hard versus easy trials of the DDT showed that, compared with CTLs, the HCV+ group exhibited less activation in the left lateral occipital gyrus, precuneus, and superior frontal gyrus. There were also significant interactive effects for hard-easy contrasts in the bilateral medial frontal gyrus, left insula, left precuneus, left inferior parietal lobule, and right temporal occipital gyrus; the CTL group evidenced a positive relationship between impulsivity and activation, while the HCV+ group exhibited a negative relationship. Within the HCV+ group, those with high viral load chose immediate rewards more often than those with low viral load, regardless of choice difficulty; those with low viral load chose immediate rewards more often on hard choices relative to easy choices. Results show that HCV+ patients exhibit greater impulsive behavior when presented with difficult choices, and impulsivity is negatively related to activation in regions important for cognitive control. Thus, interventions that decrease impulsive choice may be warranted with some HCV+ patients.

Mechanisms of neuropathogenesis in HIV and HCV: similarities, differences, and unknowns

HIV and hepatitis C virus (HCV) have both been associated with cognitive impairment. Combination antiretroviral therapy (cART) has dramatically changed the nature of cognitive impairment in HIV-infected persons, while the role of direct-acting antivirals (DAA) in neurocognition of HCV-infected individuals remains unclear. Also, whether HIV and HCV interact to promote neurocognitive decline or whether they each contribute an individual effect continues to be an open question. In this work, we review the virally mediated mechanisms of HIV- and HCV-mediated neuropathogenesis, with an emphasis on the role of dual infection, and discuss observed changes with HIV viral suppression and HCV functional cure on neurocognitive impairments.

Interferon-free therapy in hepatitis C virus (HCV) monoinfected and HCV/HIV coinfected patients: effect on cognitive function, fatigue, and mental health

The efficacy and safety of interferon-free therapies for hepatitis C virus (HCV) infection have been reported. Considering the accumulating evidence for a direct central nervous system infection by HCV, we aim to evaluate the effect of direct acting antivirals (DAA) therapy on cognitive function in HCV patients. We conducted a longitudinal analysis of the cognitive performance of 22 patients (8 HCV+, 14 HCV+/HIV+) who completed neuropsychological testing at baseline and at week 12 after DAA therapy. In 20 patients, we analyzed specific attention parameters derived from an experimental testing based on the Theory of Visual Attention (TVA). Depression, fatigue, and mental health were assessed as patient reported outcomes. At baseline, 54.5% of the patients met the criteria for cognitive impairment and 40% showed impairment in TVA parameters. Follow-up analysis revealed significant improvements in the domains of visual memory/learning, executive functions, verbal fluency, processing speed, and motor skills but not in verbal learning and attention/working memory. We did not observe significant improvement in visual attention measured by TVA. Fatigue and mental health significantly improved at follow-up. Our findings indicate that successful DAA treatment leads to cognitive improvements in several domains measured by standard neuropsychological testing. The absence of improvement in TVA parameters and of significant improvement in the domain of attention/working memory might reflect the persistence of specific cognitive deficits after HCV eradication. In summary, DAA treatment seems to have a positive effect on some cognitive domains and leads to an improvement in mental health and fatigue in HCV-infected patients.

Systematic review with meta-analysis: neuroimaging in hepatitis C chronic infection

BACKGROUND

Chronic hepatitis C is considered a systemic disease because of extra-hepatic manifestations. Neuroimaging has been employed in hepatitis C virus-infected patients to find in vivo evidence of central nervous system alterations.

AIMS

Systematic review and meta-analysis of neuroimaging research in chronic hepatitis C treatment naive patients, or patients previously treated without sustained viral response, to study structural and functional brain impact of hepatitis C.

METHODS

Using PRISMA guidelines a database search was conducted from inception up until 1 May 2017 for peer-reviewed studies on structural or functional neuroimaging assessment of chronic hepatitis C patients without cirrhosis or encephalopathy, with control group. Meta-analyses were performed when possible.

RESULTS

The final sample comprised 25 studies (magnetic resonance spectroscopy [N = 12], perfusion weighted imaging [N = 1], positron emission tomography [N = 3], single-photon emission computed tomography [N = 4], functional connectivity in resting state [N = 1], diffusion tensor imaging [N = 2] and structural magnetic resonance imaging [N = 2]). The whole sample was of 509 chronic hepatitis C patients, with an average age of 41.5 years old and mild liver disease. A meta-analysis of magnetic resonance spectroscopy studies showed increased levels of choline/creatine ratio (mean difference [MD] 0.12, 95% confidence interval [CI] 0.06-0.18), creatine (MD 0.85, 95% CI 0.42-1.27) and glutamate plus glutamine (MD 1.67, 95% CI 0.39-2.96) in basal ganglia and increased levels of choline/creatine ratio in centrum semiovale white matter (MD 0.13, 95% CI 0.07-0.19) in chronic hepatitis C patients compared with healthy controls. Photon emission tomography studies meta-analyses did not find significant differences in PK11195 binding potential in cortical and subcortical regions of chronic hepatitis C patients compared with controls. Correlations were observed between various neuroimaging alterations and neurocognitive impairment, fatigue and depressive symptoms in some studies.

CONCLUSIONS

Patients with chronic hepatitis C exhibit cerebral metabolite alterations and structural or functional neuroimaging abnormalities, which sustain the hypothesis of hepatitis C virus involvement in brain disturbances.

Expert opinion on managing chronic HCV in patients with neuropsychiatric manifestations

Neurological manifestations of HCV infection appear to be under-recognized in clinical practice despite the majority of HCV-infected patients experiencing symptoms such as fatigue, depression and cognitive dysfunction. There is also growing evidence for a link between HCV infection and an increased risk of Parkinson's disease. The mechanism underpinning the association between HCV and these neuropsychiatric syndromes still requires further investigation. Here we review the pre-clinical and clinical evidence for a link between HCV and effects on the central nervous system leading to neuropsychiatric syndromes. Lastly, we describe how improvements in neuropsychiatric manifestations of HCV following treatment have been observed, which is subsequently reflected in an overall improvement in health-related quality of life.

Microglia at center stage: a comprehensive review about the versatile and unique residential macrophages of the central nervous system

Microglia cells are the unique residential macrophages of the central nervous system (CNS). They have a special origin, as they derive from the embryonic yolk sac and enter the developing CNS at a very early stage. They play an important role during CNS development and adult homeostasis. They have a major contribution to adult neurogenesis and neuroinflammation. Thus, they participate in the pathogenesis of neurodegenerative diseases and contribute to aging. They play an important role in sustaining and breaking the blood-brain barrier. As innate immune cells, they contribute substantially to the immune response against infectious agents affecting the CNS. They play also a major role in the growth of tumours of the CNS. Microglia are consequently the key cell population linking the nervous and the immune system. This review covers all different aspects of microglia biology and pathology in a comprehensive way.

Interactions Between Platelets and Inflammatory Monocytes Affect Sickness Behavior in Mice With Liver Inflammation

BACKGROUND & AIMS

Patients with inflammatory liver disease commonly develop debilitating symptoms, called sickness behaviors, which arise via changes in brain function. Monocytes that produce tumor necrosis factor interact with cerebral endothelial cells to activate microglial cells and promote sickness behavior. Platelets regulate inflammation, and aggregates of monocytes and platelets are increased in the circulation of patients with liver disease. We investigated the role of platelets in inducing inflammatory features of circulating monocytes and promoting sickness behaviors in mice with cholestatic liver injury.

METHODS

We performed bile-duct ligations or sham surgeries on C57BL/6 or toll-like receptor 4 (TLR4)-knockout mice to induce liver inflammation. Liver inflammation was also induced in a separate group of mice by administration of concanavalin A. Circulating platelets, aggregates of monocytes and platelets, and activation of microglial cells were measured by flow cytometry. To deplete platelets, mice were given anti-thrombocyte serum or normal rabbit serum (control) 4 days after surgery. Interactions between monocytes and cerebral endothelial cells were analyzed by intravital microscopy. Sickness behaviors were quantified based on time spent by adult mice engaging in social behaviors toward a juvenile mouse, compared with time spent in nonsocial behavior or remaining immobile.

RESULTS

Aggregates of monocytes and platelets in circulation of mice increased significantly following bile-duct ligation. Platelet-monocyte interactions were required for activation of inflammatory monocytes and production of tumor necrosis factor. Platelet depletion greatly reduced adhesive interactions between inflammatory monocytes and adhesive interactions with cerebral endothelial cells and activation of the microglia, as well as development of sickness behavior. Furthermore, TLR4 signaling was important for aggregation of monocytes and platelets, and development of sickness behavior following bile-duct ligation. These findings were confirmed in mice with concanavalin A-induced liver injury.

CONCLUSIONS

In mice with liver inflammation, we found TLR4 and aggregates of monocytes and platelets to regulate microglial activation and development of sickness behavior. These findings might lead to new therapeutic strategies for liver disease-associated symptoms.

Persistent neuropsychiatric impairment in HCV patients despite clearance of the virus?!

One of the most disabling symptoms of hepatitis C virus (HCV) infection is chronic fatigue. While this is accepted for HCV polymerase chain reaction (PCR)-positive patients, a relationship between HCV infection and chronic fatigue is questioned after successful virus eradication. As fatigue is a subjective criterion, we aimed to evaluate in addition mood alterations and cognitive function in HCV-exposed patients with only mild liver disease and to assess a) possible interrelationships between these factors and health-related quality of life and b) the impact of viremia and former interferon treatment. One hundred and fifty-nine anti-HCV-positive individuals without advanced liver disease answered health-related quality of life (HRQoL), fatigue and depression questionnaires and underwent a battery of attention and memory tests. Accompanying diseases which could distort the results of the study such as HIV co-infection or drug addiction were exclusion criteria. The patients were subdivided into four groups according to their viremia status and interferon treatment history. Patients' data were evaluated with respect to norms given in the respective test manuals and in addition compared to those of 33 age-matched healthy controls. Eighty-five per cent of the patients had chronic fatigue, 50-60% mild depression or anxiety, 45% memory deficits and 30% attention deficits, irrespective of their HCV viremia status or treatment history. HRQoL correlated negatively with chronic fatigue (P<.001), while cognitive deficits-especially memory function-were independent from fatigue and depression. HCV infection may cause long-standing cerebral dysfunction that significantly impairs HRQoL and may even persist after clearance of the virus.

Functional connectivity alterations in patients with chronic hepatitis C virus infection: A multimodal MRI study

Chronic hepatitis C virus (HCV) infection is associated with fatigue and depression. Cognitive impairments are also reported in a smaller number of HCV-positive patients. Recent studies linked HCV to low-grade inflammation in brain. Here, we test the hypothesis that chronic HCV is associated with 3T-neuroimaging-derived grey matter volume (GMV) and functional connectivity alterations in a sample of chronic HCV (1b), without severe liver disease. Regional GMV and resting-state fMRI-derived eigenvector centrality (EC) were compared between 19 HCV-positive patients and 23 healthy controls (all females, 50-69 and 52-64 years, respectively), controlling for white matter hyperintensities and age. Standard tests were used to assess fatigue, depression and cognitive performance. Also, liver fibrosis stage and viral load were quantified among patients. In comparison with controls, HCV-positive patients had higher scores in fatigue and depression, and worse alertness scores. The groups performed similarly in other cognitive domains. We report higher EC in a cluster in the right anterior superior parietal lobule in patients, while no differences are found in GMV. Post hoc functional connectivity analysis showed increased connectivity of this cluster with primary and secondary somatosensory cortex, and temporal and occipital lobes in patients. Higher mean EC in the superior parietal cluster, adjusted for mean framewise displacement, was associated with better memory and attention performance, but not with fatigue, depression, viral load or level of liver fibrosis, among patients. These results suggest a compensatory mechanism in chronic hepatitis C and explain equivocal results in the literature about cognitive deficits in infected persons. Further studies should define the relation of these connectivity changes to the brain's inflammatory activity.

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.