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

Serum biomarkers of liver fibrosis identify globus pallidus vulnerability

The CNS manifestation of chronic liver disease can include magnetic resonance (MR) signal hyperintensities in basal ganglia structures. Here, relations between liver (serum-derived fibrosis scores) and brain (regional T1-weighted signal intensities and volumes) integrity were evaluated in a sample of 457 individuals including those with alcohol use disorders (AUD), people living with human immunodeficiency virus (HIV), those comorbid for AUD and HIV, and healthy controls. Liver fibrosis was identified from cutoff scores as follows: aspartate aminotransferase to platelet ratio index (APRI) > 0.7 in 9.4% (n = 43) of the cohort; fibrosis score (FIB4) > 1.5 in 28.0% (n = 128) of the cohort; and non-alcoholic fatty liver disease fibrosis score (NFS) > -1.4 in 30.2% (n = 138) of the cohort. Presence of serum-derived liver fibrosis was associated with high signal intensities selective to basal ganglia (i.e., caudate, putamen, and pallidum) structures. High signal intensities in the pallidum, however, explained a significant portion of the variance in APRI (25.0%) and FIB4 (23.6%) cutoff scores. Further, among the regions evaluated, only the globus pallidus showed a correlation between greater signal intensity and smaller volume (r = -0.44, p <.0001). Finally, higher pallidal signal intensity correlated worse ataxia (eyes open ρ = -0.23, p =.0002; eyes closed ρ = -0.21, p =.0005). This study suggests that clinically relevant serum biomarkers of liver fibrosis such as the APRI may identify individuals vulnerable to globus pallidus pathology and contribute to problems with postural balance.

Association of liver disease with brain volume loss, cognitive decline, and plasma neurodegenerative disease biomarkers

Although liver dysfunction has been implicated in Alzheimer's disease (AD), it remains unknown how liver disease may influence the trajectory of brain and cognitive changes in older adults. We related self-reported liver disease to longitudinal measures of brain structure and cognition, as well as baseline measures of plasma AD/neurodegeneration biomarkers in the Baltimore Longitudinal Study of Aging. Liver disease was identified using ICD-9 classification codes. Brain volume and cognition were assessed serially using 3T-MRI and a cognitive battery. 1008, 2157, and 780 participants were included in the MRI, cognitive, and plasma biomarker analysis, respectively. After adjustment for confounders, liver disease was associated with accelerated decline in total brain and white matter volume, but not total gray matter or AD signature region volume. Although liver disease showed no relationship with domain-specific cognitive decline or plasma biomarkers, participants with a history of hepatitis demonstrated accelerated decline in verbal fluency and elevated neurofilament light. Results suggest all-cause liver disease may accelerate brain volume loss but does not appear to promote AD-specific neurocognitive changes.

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.

Preliminary Evidence for a Relationship between Elevated Plasma TNFα and Smaller Subcortical White Matter Volume in HCV Infection Irrespective of HIV or AUD Comorbidity

Classical inflammation in response to bacterial, parasitic, or viral infections such as HIV includes local recruitment of neutrophils and macrophages and the production of proinflammatory cytokines and chemokines. Proposed biomarkers of organ integrity in Alcohol Use Disorders (AUD) include elevations in peripheral plasma levels of proinflammatory proteins. In testing this proposal, previous work included a group of human immunodeficiency virus (HIV)-infected individuals as positive controls and identified elevations in the soluble proteins TNFα and IP10; these cytokines were only elevated in AUD individuals seropositive for hepatitis C infection (HCV). The current observational, cross-sectional study evaluated whether higher levels of these proinflammatory cytokines would be associated with compromised brain integrity. Soluble protein levels were quantified in 86 healthy controls, 132 individuals with AUD, 54 individuals seropositive for HIV, and 49 individuals with AUD and HIV. Among the patient groups, HCV was present in 24 of the individuals with AUD, 13 individuals with HIV, and 20 of the individuals in the comorbid AUD and HIV group. Soluble protein levels were correlated to regional brain volumes as quantified with structural magnetic resonance imaging (MRI). In addition to higher levels of TNFα and IP10 in the 2 HIV groups and the HCV-seropositive AUD group, this study identified lower levels of IL1β in the 3 patient groups relative to the control group. Only TNFα, however, showed a relationship with brain integrity: in HCV or HIV infection, higher peripheral levels of TNFα correlated with smaller subcortical white matter volume. These preliminary results highlight the privileged status of TNFα on brain integrity in the context of infection.

Medical Conditions Linked to Atherosclerosis Are Associated With Magnified Cortical Thinning in Individuals With Alcohol Use Disorders

AIMS

Magnetic resonance imaging (MRI) studies report widespread cortical thinning in individuals with alcohol use disorder (AUD), but did not consider potential effects of pro-atherogenic conditions such as hypertension, type 2 diabetes mellitus, hepatitis C seropositivity and hyperlipidemia on cortical thickness. The conditions are associated with regional cortical thinning in those without AUD. We predicted that individuals with concurrent AUD and pro-atherogenic conditions demonstrate the greatest regional cortical thinning in areas most vulnerable to decreased perfusion.

METHODS

Treatment-seeking individuals with AUD (n = 126) and healthy controls (CON; n = 49) completed a 1.5 T MRI study. Regional cortical thickness was quantitated via FreeSurfer. Individuals with AUD and pro-atherogenic conditions (Atherogenic+), AUD without pro-atherogenic conditions (Atherogenic-) and CON were compared on regional cortical thickness.

RESULTS

Individuals with AUD showed significant bilateral cortical thinning compared to CON, but Atherogenic+ demonstrated the most widespread and greatest magnitude of regional thinning, while Atherogenic- had reduced thickness primarily in anterior frontal and posterior parietal lobes. Atherogenic+ also showed a thinner cortex than Atherogenic- in lateral orbitofrontal and dorso/dorsolateral frontal cortex, mesial and lateral temporal and inferior parietal regions.

CONCLUSIONS

Our results demonstrate significant bilateral cortical thinning in individuals with AUD relative to CON, but the distribution and magnitude were influenced by comorbid pro-atherogenic conditions. The magnitude of cortical thinning in Atherogenic+ strongly corresponded to cortical watershed areas susceptible to decreased perfusion, which may result in morphometric abnormalities. The findings indicate that pro-atherogenic conditions may contribute to cortical thinning in those seeking treatment for AUD.

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.

Cognitive impairments in HCV infection: From pathogenesis to neuroimaging

Extrahepatic manifestations of hepatitis C virus (HCV) infection, in particular cognitive impairments, can be present in the absence of clinical liver dysfunction. Executive memory, attention, and concentration are cognitive domains that are most frequently affected. Microstructural and functional changes in cortical gray matter and basal ganglia associate these neuropsychiatric changes in early HCV infection. No study has covered the relationship between imaging features of HCV-related cognitive impairment and HCV pathology. Herein we summarize evidence suggesting a direct pathology of HCV in microglia, astrocytes, and microvascular endothelial cells, and a neuroinflammatory response in HCV-related cognitive decline. Lipoproteins and their receptors mediate HCV infectivity in the central nervous system and confer susceptibility to HCV-related cognitive decline. Magnetic resonance spectroscopy has revealed changes compatible with reactive gliosis and microglial activation in basal ganglia, frontal and occipital white matter, in the absence of cirrhosis or hepatic encephalopathy. Similarly, diffusion imaging shows evidence of structural disintegrity in the axonal fibers of white matter tracts associated with temporal and frontal cortices. We also discuss the cognitive benefits and side-effects of the two most popular therapeutic protocols interferon-based therapy and interferon-free therapy using direct acting anti-virals. Evidences support a network-based pattern of disruption in functional connectivity in HCV patients and a common neuronal substrate for HCV-related and interferon-therapy-associated cognitive decline. These evidences might help identify patients who benefit from either interferon-based or interferon-free treatment regimen.

HIV infection and age effects on striatal structure are additive

The age of the HIV-infected population is increasing. Although many studies document gray matter volume (GMV) changes following HIV infection, GMV also declines with age. Findings have been inconsistent concerning interactions between HIV infection and age on brain structure. Effects of age, substance use, and inadequate viral suppression may confound identification of GMV serostatus effects using quantitative structural measures. In a cross-sectional study of HIV infection, including 97 seropositive and 84 seronegative, demographically matched participants, ages 30-70, we examined serostatus and age effects on GMV and neuropsychological measures. Ninety-eight percent of seropositive participants were currently treated with anti-retroviral therapies and all were virally suppressed. Gray, white, and CSF volumes were estimated using high-resolution T1-weighted MRI. Linear regression modeled effects of serostatus, age, education, comorbidities, and magnetic field strength on brain structure, using both a priori regions and voxel-based morphometry. Although seropositive participants exhibited significant bilateral decreases in striatal GMV, no serostatus effects were detected in the thalamus, hippocampus, or cerebellum. Age was associated with cortical, striatal, thalamic, hippocampal, and cerebellar GMV reductions. Effects of age and serostatus on striatal GMV were additive. Although no main effects of serostatus on neuropsychological performance were observed, serostatus moderated the relationship between pegboard performance and striatal volume. Both HIV infection and age were associated with reduced striatal volume. The lack of interaction of these two predictors suggests that HIV infection is associated with premature, but not accelerated, brain age. In serostatus groups matched on demographic and clinical variables, there were no observed differences in neuropsychological performance. Striatal GMV measures may be promising biomarker for use in studies of treated HIV infection.

Is treated HIV infection still toxic to the brain?

Clinically apparent HIV infection, accompanied by CNS opportunistic infections and HIV encephalopathy, was often associated with profound structural and functional brain effects prior to the introduction of anti-retroviral therapy (ART). With treatment, HIV structural and functional brain effects are smaller and have not been as easily detected. With near complete elimination of CNS opportunistic infections, the HIV neuroimaging research community now grapples with the problem of detecting subtler structural and functional changes against a background of persisting confounds, such as comorbidities and clinical features common in the HIV infected population. This situation also raises the question of whether imaging measure changes that are reported as HIV brain effects are purely related to viral infection, rather than originating from confounding effects that might include age, substance use, hepatitis C coinfection, cerebrovascular risk factors, ART, premorbid cognitive skills and illness duration. In addition to cohort characteristics, variation in image acquisition and analysis techniques may also contribute to study outcome heterogeneity. We review the potential effects of these confounds on detection of HIV infection effects and discuss strategies to avoid or mitigate the effects of these confounds. We then present a systematic approach to measurement, design and analysis in HIV neuroimaging studies, combining both experimental and statistical control techniques to determine if HIV infection effects persist, fluctuate or worsen in groups achieving viral suppression from ART.

Structural and functional abnormalities of vision-related brain regions in cirrhotic patients: a MRI study

Purpose

Previous studies have focused on global cerebral alterations observed in cirrhosis. However, little was known about the specific abnormalities of vision-related brain regions in cirrhotic patients. In this study, we sought to explore neurological alterations of vision-related regions by measuring brain resting-state network connectivity, based on the structural investigation in cirrhotic patients without clinical sign of hepatic encephalopathy (HE).

Methods

Structural and functional magnetic resonance image (MRI) data were collected from 20 hepatitis B virus (HBV)-related cirrhotic patients without clinical sign of HE and from 20 healthy controls (HC). Voxel-based morphometric (VBM) analysis and brain functional network analysis were performed to detect abnormalities in cerebral structure and function.

Results

Cirrhotic patients showed regions with the most significant gray matter reduction primarily in vision-related brain regions, including the bilateral lingual gyri, left putamen, right fusiform gyrus, and right calcarine gyrus, and other significant gray matter reductions were distributed in bilateral hippocampus. Based on structural investigation focused on vision-related regions, brain functional network analysis revealed decreased functional connectivity between brain functional networks within vision-related regions (primary visual network (PVN), higher visual network (HVN), visuospatial network (VSN)) in the patient group compared with HC group.

Conclusion

These results indicate that structural and functional impairment were evident in the vision-related brain regions in cirrhotic patients without clinical sign of hepatic encephalopathy. The physiopathology and clinical relevance of these changes could not be ascertained from the present study, which provided a basis for further evolution of the disease.

Brain grey matter volume reduction and anxiety-like behavior in lipopolysaccharide-induced chronic pulmonary inflammation rats: A structural MRI study with histological validation

While there have been multiple fMRI studies into the brain functional changes after acutely stimulated peripheral infection, knowledge for the effect of chronic peripheral infection on whole brain morphology is still quite limited. The present study was designed to investigate the brain structural and emotional changes after peripheral local infection initiated chronic systemic inflammation and the relationship between circulating inflammatory markers and brain grey matter. Specifically, in-vivo T2-weighted MRI was performed on rats with lipopolysaccharide (LPS)-induced chronic pulmonary inflammation (CPI) and those without. Grey matter volume was quantified using diffeomorphic anatomical registration through exponentiated lie (DARTEL) enhanced voxel-based morphometry followed by between-group comparison. Open field experiment was conducted to test the potential anxiety-like behaviors after CPI, along with the ELISA estimated inflammatory markers were correlated to grey matter volume. Guided by image findings, we undertook a focused histological investigation with immunefluorescence and Nissl staining. A widespread decrease of grey matter volume in CPI-model rats was revealed. 8 of the 12 measured inflammatory markers presented differential neuroanatomical correlation patterns with three of the pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α) and CRP being the most notable. Lower grey matter volumes in some of the inflammatory markers related regions (amygdala, CA2 and cingulate cortex) were associated with more-severe anxiety-like behaviors. Furthermore, grey matter volumes in amygdala and CA3 were correlated negatively with the expressions of glial proteins (S100β and Nogo-A), while the grey matter volume in hypo-thalamus was changing positively with neural cell area. Overall, the neuroanatomical association patterns and the histopathology underpinning the MRI observations we demonstrated here would probably serve as one explanation for the cerebral and emotional deficits presented in the patients with CPI, which would furthermore yield new insights into the adverse effects the many other systemic inflammation and inflammatory autoimmune diseases would pose on brain morphology.

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.

The Aging Brain With HIV Infection: Effects of Alcoholism or Hepatitis C Comorbidity

As successfully treated individuals with Human Immunodeficiency Virus (HIV)-infected age, cognitive and health challenges of normal aging ensue, burdened by HIV, treatment side effects, and high prevalence comorbidities, notably, Alcohol Use Disorders (AUD) and Hepatitis C virus (HCV) infection. In 2013, people over 55 years old accounted for 26% of the estimated number of people living with HIV (~1.2 million). The aging brain is increasingly vulnerable to endogenous and exogenous insult which, coupled with HIV infection and comorbid risk factors, can lead to additive or synergistic effects on cognitive and motor function. This paper reviews the literature on neuropsychological and in vivo Magnetic Resonance Imaging (MRI) evaluation of the aging HIV brain, while also considering the effects of comorbidity for AUD and HCV.

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.