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

Blood-borne viruses and neurological manifestations: An overview

Infections caused by blood-borne viruses, such as human immunodeficiency virus (HIV), human T-lymphotropic virus (HTLV), hepatitis C virus (HCV), and hepatitis B virus (HBV), are systemic diseases that can lead to a wide range of pathological manifestations. Besides causing severe immune and hepatic disorders, these viral pathogens can also induce neurological dysfunctions via both direct and indirect mechanisms. Neurological dysfunctions are one of the most common manifestations caused by these viruses that can also serve as indicators of their infection, impacting the clinical presentation of the disease. The main neurological manifestations of these blood-borne viral pathogens consist of several central and peripheral nervous system (CNS and PNS, respectively) dysfunctions. The most common neurological manifestations of HIV, HTLV, HCV, and HBV include HIV-associated peripheral neuropathy (PN), HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), and HCV-/HBV-associated PN, respectively. Nonetheless, patients infected with these viruses may experience other neurological disorders, either associated with these conditions or manifesting in isolation, which can often go unnoticed or undiagnosed by physicians. The present review aims to provide an overview of the latest evidence on the relationship between blood-borne viruses and neurological disorders to highlight neurological conditions that may be somewhat overlooked by mainstream literature and physicians.

Association of Cognitive Impairment With Chronic Viral Hepatitis Among Older Adults in Taiwan

OBJECTIVE

To evaluate the risk of cognitive impairment among patients with chronic viral hepatitis.

DESIGN

A cross-sectional study.

SETTING

Population-based.

PARTICIPANTS

Individuals 60 years or older were enrolled from the Taiwan Biobank database from 2012.

EXPOSURE

Hepatitis B virus and hepatitis C virus infections.

MEASUREMENT

Cognitive impairment was evaluated using the mini-mental state examination (MMSE). Logistic regression models were used to calculate odds ratios and 95% confidence intervals (CIs). The effects of APOE ε4 polymorphisms on the association between viral hepatitis and the risk of cognitive impairment were also investigated.

RESULTS

We recruited 912 participants with cognitive impairment and 22 869 participants without cognitive impairment. The adjusted odds ratio (aOR) for cognitive impairment was 1.38 (95% CI: 1.03-1.85, p = 0.033) among participants with hepatitis C virus infection and 1.14 (95% CI: 0.91-1.43, p = 0.257) among participants with hepatitis B virus infection. Participants with hepatitis C virus infection and without hepatitis B virus infection had a higher risk of cognitive impairment (aOR: 1.52, 95% CI: 1.13-2.04, p = 0.006). The MMSE subcategories most associated with hepatitis C virus infection were orientation and design copying. The association between hepatitis C virus infection and cognitive impairment was higher among participants with ε4 alleles of the APOE gene than among those without alleles (aOR: 2.18, 95% CI: 1.21-3.91, p = 0.009).

CONCLUSIONS

Our findings suggest that individuals 60 years or older with chronic hepatitis C virus infection are at increased risk of cognitive impairment.

Aspects of cognitive assessments and spectroscopic magnetic resonance imaging in people with chronic hepatitis C: a systematic review

Extrahepatic manifestations are common in people with hepatitis C virus (HCV). Cognitive changes are pointed out, but the mechanisms are still uncertain. The aim of this systematic review was to analyze studies involving spectroscopic magnetic resonance in people infected with HCV, which also included cognitive tests. The research occurred in six databases (Directory of Open Access Journals, Lilacs, Medcaribe, Medline, Scielo and ScienceDirect) and the selection of studies was carried out in two stages: search for titles and abstracts, then reading of the full articles, excluding those that did not meet the eligibility criteria. 12,888 titles and abstracts were selected, but only 6 articles were included in the review. Impairments in attention, concentration, speed of information processing, memory, verbal fluency and executive functions were identified as well as an increase in the Cho/Cr and mI/Cr ratios and a reduction in the NAA/Cr ratio in some included studies. Longitudinal studies, with more homogeneous samples and methods, as well as with better controlled confounding factors, are necessary to adequately identify the effect of HCV on the brain.

Neurological and psychiatric effects of hepatitis C virus infection

Hepatitis C virus (HCV) infection is widespread and affects 71 million people worldwide. Although hepatic manifestations are the most frequent, ranging from chronic hepatitis to cirrhosis and hepatocellular carcinoma, it is also associated with several extrahepatic manifestations. Infected patients may present non-specific neurological symptoms, regardless of the presence of liver cirrhosis. Several pathogenetic mechanisms underlying neurological symptoms have been hypothesized: neuroinvasion, immune-mediated damage, neurotransmitter alterations and cryoglobulinemia. Alterations of the central nervous system include cerebral vasculopathy, acute or subacute encephalopathy and inflammatory disorders. HCV infection may be responsible for neuropathies, of which the most frequent form is symmetrical axonal sensory or sensory-motor polyneuropathy which causes loss of leg sensitivity and weakness. Up to 50% of patients with HCV infection may experience cognitive decline and psychological disorders, such as depression and fatigue. HCV associated neurocognitive disorder is independent of the presence of liver cirrhosis and affects different domains than in patients with hepatic encephalopathy. It can be studied using specific tests that mainly explore executive functions, verbal learning and verbal recall. These disorders significantly reduce the quality of life. The new antiviral therapies improve the extrahepatic symptoms of HCV infection and their success depends on the achievement of sustained virological response. However, the effect of therapy may differ depending on the type of organ involved; neurological symptoms can be irreversible if there is organic liver damage. The aim of this review is to provide a critical overview of physiopathological mechanisms, diagnostic and therapeutic strategies of the neurological and psychiatric effects of HCV infection.

Apolipoprotein E polymorphism influences orthotopic liver transplantation outcomes in patients with hepatitis C virus-induced liver cirrhosis

BACKGROUND

Hepatitis C virus (HCV) infection is responsible for a chronic liver inflammation, which may cause end-stage liver disease and hepatocellular carcinoma. Apolipoprotein E (protein: ApoE, gene: APOE), a key player in cholesterol metabolism, is mainly synthesized in the liver and APOE polymorphisms may influence HCV-induced liver damage.

AIM

To determine whether APOE alleles affect outcomes in HCV-infected patients with liver cirrhosis following orthotopic liver transplantation (OLT).

METHODS

This was a cohort study in which 179 patients, both genders and aged 34-70 years, were included before or after (up to 10 years follow-up) OLT. Liver injury severity was assessed using different criteria, including METAVIR and models for end-stage liver disease. APOE polymorphisms were analyzed by quantitative real-time polymerase chain reaction.

RESULTS

The APOE3 allele was the most common (67.3%). In inflammation severity of biopsies from 89 OLT explants and 2 patients in pre-transplant, the degree of severe inflammation (A3F4, 0.0%) was significantly less frequent than in patients with minimal and moderate degree of inflammation (≤ A2F4, 16.2%) P = 0.048, in patients carrying the APOE4 allele when compared to non-APOE4. In addition, a significant difference was also found (≤ A2F4, 64.4% vs A3F4, 0.0%; P = 0.043) and (A1F4, 57.4% vs A3F4, 0.0%; P = 0.024) in APOE4 patients when compared to APOE3 carriers. The fibrosis degree of the liver graft in 8 of 91 patients and the lack of the E4 allele was associated with more moderate fibrosis (F2) (P = 0.006).

CONCLUSION

Our results suggest that the E4 allele protects against progression of liver fibrosis and degree of inflammation in HCV-infected patients.

Impact of apolipoprotein E genetic polymorphisms on liver disease: An essential review

Cirrhosis is an advanced stage of liver disease, compromising liver function with systemic health implications and poor quality of life. Hepatitis C virus (HCV) infection and alcoholic liver disease are the main causes of this pathology. However, since genetic factors may play a large role in the progression and severity of liver disease, and as apolipoprotein E (apoE) has been recognised to be mainly synthesised in the liver, apoE polymorphism studies are important to better understand the causal mechanisms in liver diseases. In this review, we summarise up-to-date studies addressing how apoE polymorphisms influence liver cirrhosis and liver transplantation outcomes and potential protective mechanisms. Although more clinical studies are needed to support these findings, the apoE ɛ4 allele seems to be protective against the progression of liver cirrhosis in the majority of aetiologies and the postoperative serum apoE phenotype of the transplanted subject receptors was converted to that of the donor, indicating that >90% of apoE in plasma is synthesised in the hepatic system.

APOE ϵ4 modifies the relationship between infectious burden and poor cognition

OBJECTIVE

We investigated whether APOE ϵ4 is an effect modifier of the association between infectious burden (IB) and poor cognition in a multiethnic cohort, the Northern Manhattan Study.

METHODS

IB was assessed by a quantitative weighted index of exposure to common pathogens associated with vascular risk, infectious burden index (IBI), and by serology for individual infections. Cognition was assessed by completion of the Mini-Mental State Examination at baseline and a full neuropsychological test battery after a median follow-up of approximately 6 years. Adjusted linear and logistic regressions estimated the association between IBI and cognition, with a term included for the interaction between APOE ϵ4 and IBI.

RESULTS

Among those with full neuropsychological test results (n = 569), there were interactions between IBI and APOE ϵ4 (p = 0.07) and herpes simplex virus 1 (HSV-1) and APOE ϵ4 (p = 0.02) for processing speed. IBI was associated with slower processing speed among non-ϵ4 carriers (β = -0.08 per SD change in IBI, 95% confidence interval [CI] -0.16 to -0.01), but not among APOE ϵ4 carriers (β = 0.06 per SD change in IBI, 95% CI -0.08 to 0.19). HSV-1 positivity was associated with slower processing speed among non-ϵ4 carriers (β = -0.24, 95% CI -0.45 to -0.03), but not among APOE ϵ4 carriers (β = 0.27, 95% CI -0.09 to 0.64).

CONCLUSIONS

Potential effect modification by the APOE ϵ4 allele on the relationship of infection, and particularly viral infection, to cognitive processing speed warrants further investigation.

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.

Hepatitis C virus-related symptoms, but not quality of life, were improved by treatment with direct-acting antivirals

AIM

Direct-acting antivirals (DAAs) for the treatment of hepatitis C virus (HCV) infection have a significantly high sustained virologic response rate after a short treatment course and do not have any severe adverse effects. Patient-reported outcomes (PROs) have become increasingly important to assess the total impact of a chronic disease. We aimed to evaluate the changes in symptoms of patients with HCV infection treated with DAAs by using PROs.

METHODS

A total of 107 patients with chronic HCV infection were treated with DAAs. Daclatasvir/asunaprevir or sofosbuvir/ledipasvir was used for HCV 1B infection, and sofosbuvir/ribavirin for HCV 2A/2B infection. The PROs measured at the start of treatment and 1 year after the start of treatment were cirrhosis-related symptom score (CSS), presence of restless legs syndrome (RLS), Epworth sleepiness scale (ESS), Pittsburg sleep quality index (PSQI), Kessler 6 score (K-6), and the SF-36 to measure quality of life (QOL). All patients had a sustained virologic response rate of 24.

RESULTS

The CSS, PSQI, K-6, and RLS scores were improved 1 year after beginning treatment. However, QOL had not recovered. Changes in total CSS were correlated with HCV genotype, sex, hypertensive drug use, serum low-density lipoprotein, and ESS at the start of treatment and RLS 1 year after the start of treatment. The factors that contributed to worsening of CSS were HCV genotype 2B and RLS 1 year after the start of treatment.

CONCLUSION

Treatment with DAAs eliminated HCV-RNA and improved most symptoms, but QOL did not recover.

Cognitive Dysfunction and Single Nucleotide Polymorphisms in Hepatitis C Virus-Infected Persons: A Systematic Review

The aim of this study was to realize a systematic review to identify data reported in the literature involving people infected by hepatitis C virus (HCV) with cognitive dysfunctions and single nucleotide polymorphisms (SNPs). The research was realized in six databases and the selection of studies was performed in two stages. Initially, we searched indexed articles from the following electronic databases: SciELO, MEDLINE, PubMed, HighWire, LILACS, and ScienceDirect. Then the articles were completely read and those that did not meet the eligibility criteria were excluded. Therefore, 5,669 articles were obtained and, of these, 25 were selected. Finally, one article involving people with HCV and cognitive impairment was included in the review. The frequency of the APOE-ɛ4 allele in people with HCV and mild liver disease was significantly lower in those with work memory impairment (p = 0.003) and attention (p = 0.008). This situation differs from other studies that showed an association between ɛ4 allele high frequency and cognitive decline. Thus, studies with larger samples involving people with HCV, cognitive alterations, and SNPs are necessary, in view of the lack of this theme in the literature and the divergences in the findings.