A review of cognitive impairment and cerebral metabolite abnormalities in patients with hepatitis C infection

Numerous studies have reported associations between chronic hepatitis C virus (HCV) infection and fatigue, depression and impairments in health-related quality of life, which are independent of the severity of liver disease. Although there are a large number of potential explanations for these symptoms, including a history of substance abuse and associated personality types, or the effect of the diagnosis of HCV infection itself, there has been recent interest in the possibility of a biological effect of HCV infection on cerebral function. There is emerging evidence of mild, but significant neurocognitive impairment in HCV infection, which cannot be wholly attributed to substance abuse, co-existent depression or hepatic encephalopathy. Impairments are predominantly in the domains of attention, concentration and information processing speed. Furthermore, in-vivo cerebral magnetic resonance spectroscopy studies in patients with hepatitis C and normal liver function have reported elevations in cerebral choline-containing compounds and reductions in N-acetyl aspartate, suggesting that a biological mechanism may underlie the cognitive findings. The recent detection of HCV genetic sequences in post-mortem brain tissue raises the intriguing possibility that HCV infection of the central nervous system may be related to the reported neuropsychological symptoms and cognitive impairment.     

Hepatitis C virus infection affects the brain-evidence from psychometric studies and magnetic resonance spectroscopy

BACKGROUND/AIMS: Up to 50% of patients infected with the hepatitis C virus (HCV) complain of chronic fatigue and difficulties in concentration and memory. The aim of the present study was to seek evidence for the presence of central nervous system involvement in HCV infected patients with only mild liver disease. METHODS: Thirty HCV infected patients with normal liver function, 15 of whom were identified as having mild and 15 moderate to severe fatigue using the fatigue impact scale, underwent neurological and neuropsychological examination, electroencephalography (EEG) and cerebral proton magnetic resonance imaging (MRI) and spectroscopy (MRS). Fifteen healthy volunteers, matched for age and educational attainment, served as controls. RESULTS: In comparison to the healthy controls the patients with HCV infection showed evidence of cognitive impairment, primarily attention and higher executive functions, higher levels of anxiety and depression and impairment of quality of life. In addition they showed a significant decrease of the N-acetyl-aspartate/creatine ratio in the cerebral cortex on 1H MRS while the EEG was slowed in 25%. In general the deficits were more marked in the patients with moderate rather than mild fatigue. CONCLUSIONS: The data provide evidence of central nervous system involvement in patients with HCV infection.     

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

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

Impact of hepatitis C coinfection on cognitive outcomes in HIV-infected individuals

Hepatitis C virus (HCV) infection has emerged as an important factor in determining the presence and severity of cognitive impairment among individuals infected with HIV. Studies have demonstrated that coinfected patients perform worse on neuropsychological testing than monoinfected patients, typically on tests of processing speed, psychomotor speed, and learning efficiency. The mechanisms associated with this increased severity of cognitive impairment have not been identified, though a number of candidates have been proposed. This review summarizes the current literature on HIV-HCV coinfection and cognitive impairment and describes possible mechanisms mediating this relationship. Special emphasis is placed on the presence of HCV in the brain and concomitant liver disease as primary factors that may drive cognitive impairment in this population. The article concludes with suggestions for further research that are aimed toward more fully defining the neural substrates of cognitive impairment in coinfected patients.     

Central nervous system changes in hepatitis C virus infection

Patients with chronic hepatitis C virus (HCV) infection frequently describe neuropsychological symptoms. Although hepatic encephalopathy is the best established neurological association of HCV infection, there is a growing body of literature on cerebral dysfunction, occurring at an early stage of chronic HCV infection, well before the development of cirrhosis. In this review we describe recent studies that have documented mild, but significant neurocognitive impairment in HCV infection. These deficits in patients with minimal or absent liver disease do not appear to be attributable to a history of substance abuse, coexistent depression or hepatic encephalopathy. Recent studies employing in-vivo magnetic resonance spectroscopy have suggested that a biological mechanism associated with the virus may be responsible. The hypothesis that HCV infection of the central nervous system may be related to the reported neuropsychological symptoms and cognitive impairment is supported by molecular virological studies of post-mortem brain tissue.     

Central Nervous System Involvement in Hepatitis C Virus Infection

Hepatic encephalopathy is the most obvious neurological consequence of chronic hepatitis C virus (HCV) infection. There are also case reports of HCV-associated cerebral vasculitis. This review is concerned with the possibility of an effect of HCV on cerebral dysfunction, occurring at an early stage of chronic infection, prior to the development of cirrhosis and unrelated to vasculitis. There is emerging evidence of mild, but significant neurocognitive impairment in HCV infection, which cannot be attributed to substance abuse, coexistent depression, or hepatic encephalopathy. In vivo magnetic resonance spectroscopy and neurophysiological studies have suggested that a biological mechanism may underlie these cognitive findings. The recent detection of HCV genetic sequences in postmortem brain tissue raises the intriguing possibility that HCV infection of the central nervous system may be related to the reported neuropsychological symptoms and cognitive impairment.     

Neuropsychological alterations in hepatitis C infection: the role of inflammation

About 50% of patients with hepatitis C virus(HCV)infection complain of neuropsychiatric symptoms,brain fog,weakness,fatigue,and exhibit some degree of quality of life impairment,irrespective of the severity of liver disease.Since the first observation of HCV-related cognitive deficits,10 studies have been published that have evaluated neuropsychiatric performance in patients with HCV infection and different degrees of hepatic impairment.Unfortunately,these have often included patients with cirrhosis,patient...     

Neuropsychological function in Greek patients with chronic hepatitis C.

BACKGROUND: Research has shown that hepatitis C virus (HCV) infection is associated with subclinical neuropsychological deficits in the absence of hepatic encephalopathy. METHODS: The current study assessed 32 Greek HCV patients without hepatic encephalopathy using standardized neuropsychological measures and compared them with 20 healthy controls and 29 hepatitis B virus (HBV)-infected patients. Patients and controls did not differ on age, educational level, depression or fatigue severity. Moreover, strict criteria were used to exclude any risk factor for cognitive impairment. RESULTS: Chronic HCV patients performed significantly worse than healthy controls on verbal learning and memory (P=0.029). However, hepatitis C and hepatitis B patients were similarly impaired in cognitive function, suggesting that the observed abnormalities are not HCV specific. HCV patients' cognitive capacity was further associated with liver disease severity as indicated by fibrosis stage (r=-0.602, P=0.011). In contrast, cognitive decline did not correlate with patients' psychological distress, indicating that biological mechanisms might be implicated in its pathogenesis. Finally, after controlling for age and educational level, cirrhotic and non-cirrhotic patients appeared to be equally impaired. CONCLUSIONS: In conclusion, this study confirmed previous findings and added further to the existing literature concerning the negative influence of HCV infection on cognition.     

Pathogenesis of hepatitis C virus coinfection in the brains of patients infected with HIV

Involvement of the nervous system by human immunodeficiency virus (HIV) continues to be a serious problem. Among individuals with HIV who have a history of illicit drug use, those coinfected with hepatitis C virus (HCV) are a fast-growing population. However, few studies have assessed the penetration of HCV into the central nervous system (CNS) and its clinical and neuropathological impacts on HIV-infected individuals. For this purpose, the distribution of HCV was investigated in the brains of patients infected with HIV. The presence of HCV RNA in the CNS as detected by nested polymerase chain reaction was associated with a history of methamphetamine use, considerable antemortem cognitive impairment and abundant astrogliosis, and less-severe HIV encephalitis. HCV antigens were detected by immunoblot analysis, using heparin-purified brain samples, and HCV immunoreactivity was detected in astrocytes and in macrophage-microglial cells. The results support the hypothesis that HCV traffics into the HIV-infected brain, where it might lead to a productive coinfection associated with cognitive impairment.     

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

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

Cognitive impairment in HIV and HCV co-infected patients: a systematic review and meta-analysis

Cognitive impairment has been well documented in human immunodeficiency virus (HIV) and hepatitis C virus (HCV) mono-infections. However, in the context of HIV/HCV co-infection the research is more limited. The aim of this systematic review was to describe the characteristics of cognitive impairment in HIV/HCV co-infection and to examine the differences in cognitive performance between HIV/HCV and HIV and HCV mono-infected patients. Of the 437 records initially screened, 24 papers met the inclusion criteria and were included in the systematic review. Four studies were included in the meta-analysis. Most studies indicated that HIV/HCV co-infected patients had a higher level of cognitive impairment than HIV mono-infected patients. Meta-analysis also indicated that HIV mono-infected patients had a significantly lower global deficit score than co-infected patients. The results also indicated that co-infected patients were more likely to be impaired in information processing speed than HIV mono-infected patients. These findings can be challenged by biasing factors such as the small number of included studies, heterogeneity of the samples and a large diversity of methodological procedures. Future research with consistent and comprehensive neuropsychological batteries and covering a greater diversity of risk factors is needed, in order to clarify the effects of both viruses on cognitive function and the mechanisms that underlie these effects. Because cognitive impairments may pose significant challenges to medication adherence, quality of life and overall functioning, such knowledge may have important implications to the planning and implementation of effective interventions aimed at optimising the clinical management of these infections.     

Natural killer cells in hepatitis C:Current progress

Patients infected with the hepatitis C virus(HCV) are characterized by a high incidence of chronic infection, which results in chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. The functional impairment of HCV-specific T cells is associated with the evolution of an acute infection to chronic hepatitis. While T cells are the important effector cells in adaptive immunity, natural killer(NK) cells are the critical effector cells in innate immunity to virus infections. The findings of recent studies on NK cells in hepatitis C suggest that NK cell responses are indeed important in each phase of HCV infection. In the early phase, NK cells are involved in protective immunity to HCV. The immune evasion strategies used by HCV may target NK cells and might contribute to the progression to chronic hepatitis C. NK cells may control HCV replication and modulate hepatic fibrosis in the chronic phase. Further investigations are, however, needed, because a considerable number of studies observed functional impairment of NK cells in chronic HCV infection. Interestingly, the enhanced NK cell responses during interferon-α-based therapy of chronic hepatitis C indicate successful treatment. In spite of the advances in research on NK cells in hepatitis C, establishment of more physiological HCV infection model systems is needed to settle unsolved controversies over the role and functional status of NK cells in HCV infection.     

Chronic hepatitis C virus infection:Serum biomarkers in predicting liver damage

Currently, a major clinical challenge in the management of the increasing number of hepatitis C virus(HCV) infected patients is determining the best means for evaluating liver impairment. Prognosis and treatment of chronic hepatitis C(CHC) are partly dependent on the assessment of histological activity, namely cell necrosis and inflammation, and the degree of liver fibrosis. These parameters can be provided by liver biopsy; however, in addition to the risks related to an invasive procedure, liver biopsy has been associated with sampling error mostly due to suboptimal biopsy size. To avoid these pitfalls, several markers have been proposed as non-invasive alternatives for the diagnosis of liver damage. Distinct approaches among the currently available non-invasive methods are(1) the physical ones based on imaging techniques; and(2) the biological ones based on serum biomarkers. In this review, we discuss these approaches with special focus on currently available non-invasive serum markers. We will discuss:(1) class?Ⅰ?serum biomarkers individually and as combined panels, particularly those that mirror the metabolism of liver extracellular matrix turnover and/or fibrogenic cell changes;(2) class Ⅱ biomarkers that are indirect serum markers and are based on the evaluation of common functional alterations in the liver; and(3) biomarkers of liver cell death, since hepatocyte apoptosis plays a significant role in the pathogenesis of HCV infection. We highlight in this review the evidence behind the use of these markers and assess the diagnostic accuracy as well as advantages, limitations, and application in clinical practice of each test for predicting liver damage in CHC.     

Cerebral dysfunction in chronic hepatitis C infection

summary. A number of studies have reported an association between chronic hepatitis C (HCV) infection and significant impairments in health-related quality of life (QOL), which are independent of the severity of liver disease. There are numerous reports documenting the prevalence of symptoms such as fatigue and depression in chronic HCV infection, which may in part account for the reductions in quality of life. Although there are a large number of potential explanations for these symptoms, including depression and anxiety associated with the diagnosis of HCV infection or substance abuse, there has been recent interest in the possibility of a biological effect of HCV infection on cerebral function. There is emerging evidence of mild, but significant neurocognitive impairment in HCV infection, which cannot be attributed to substance abuse, coexistent depression or hepatic encephalopathy. In vivo magnetic resonance spectroscopy and neurophysiological studies have suggested that a biological mechanism may underlie these cognitive findings. The recent detection of HCV genetic sequences in post mortem brain tissue raises the intriguing possibility that HCV infection of the central nervous system may be related to the reported neuropsychological symptoms and cognitive impairment.     

Occult persistence and lymphotropism of hepatitis C virus infection

Recent discovery of occult hepatitis C virus （HCV） infection persisting after spontaneous or antiviral therapy-induced resolution of hepatitis C was made possible by the introduction of nucleic acid amplification assays capable of detecting HCV RNA at sensitivities superseding those offered by clinical tests. Although individuals with this seemingly silent HCV infection are usually anti-HCV antibody reactive and have normal liver function tests, occult HCV infection has also been reported in anti-HCV-negative individuals with persistently elevated liver enzymes of unknown etiology. Studies have shown that HCV RNA can persist for years in serum, lymphomononuclear cells and liver in the absence of clinical symptoms, although histological evidence of a mild inflammatory liver injury can be occasionally encountered. Furthermore, while HCV RNA can be detected in circulating lymphoid cells in approximately 30% of cases, a short-term culture under stimulatory conditions augments HCV replication in these cells allowing detection of virus in otherwise HCV-negative cases. HCV infects different immune cell subsets, including CD4^＋ and CD8^＋ T lymphocytes, B cells and monocytes. Studies employing clonal sequencing and single-stranded conformational polymorphism analyses have revealed unique HCV variants residing in immune cells, further strengthening the notion of HCV lymphotropism. Overall, the data accumulated suggest that occult HCV infection is a common consequence of resolution of symptomatic hepatitis C and that examination of the cells of the immune system is an effective approach to diagnosis of HCV infection and its long-term persistence. Further work is required to fully realize pathogenic and epidemiological consequences of occult HCV persistence.     

Does antiviral therapy for hepatitis B and C prevent hepatocellular carcinoma?

Approximately 75% to 80% of hepatocellular carcinomas (HCC) worldwide are attributed to chronic hepatitis B virus (HBV) and chronic hepatitis C virus (HCV) infection. Thus, effective prevention of HBV and HCV infection and progression from acute HBV and HCV infection to chronic hepatitis, cirrhosis and HCC might prevent as many as 450,000 deaths from HCC each year. The most effective approach to preventing HCC is to prevent HBV and HCV infection through vaccination. Indeed HBV vaccine is the first vaccine demonstrated to prevent cancers. However, a vaccine for HCV is not available and for persons who are chronically infected with HBV or HCV, antiviral therapy is the only option for preventing HCC. Direct evidence supporting a benefit of antiviral therapy on the prevention of HCC has been shown in a few randomized controlled trials. There is abundant evidence that antiviral therapy, in patients with long-term virological response, can improve liver histology, providing indirect support that antiviral therapy may prevent HCC by slowing progression of liver disease and possibly even reversing liver damage. Nevertheless, the risk of HCC remains in patients with chronic HBV or chronic HCV infection if treatment is initiated after cirrhosis is established. These data indicate that treatment might be of greater benefit if instituted earlier in the course of chronic hepatitis B or C. Safer, more effective, and more affordable antiviral therapies are needed for both hepatitis B and hepatitis C so more patients can benefit from treatment and more HCCs can be prevented.     

Subclinical impairment of brain function in chronic hepatitis C infection

BACKGROUND/AIMS: Central nervous system abnormalities such as fatigue and depression occur more frequently in chronic hepatitis C virus (HCV) infection than in many other causes of chronic liver disease. The finding that fatigue is unrelated to activity of hepatitis or mode of infection could indicate an independent effect of HCV on brain function. This study tested the hypothesis of a subclinical cognitive dysfunction in HCV-infected patients. METHODS: One-hundred untreated HCV-RNA positive biopsy-proven patients were investigated by P300 event-related potentials, a sensitive electrophysiologic test of cognitive processing. Health-related quality of life and fatigue were assessed using the SF-36 questionnaire and the Fatigue Impact Scale, respectively. RESULTS: Cognitive brain function was subclinically impaired in the cohort of HCV-infected patients as indicated by significantly prolonged P300 latencies (P=0.01 for comparison to matched healthy subjects) and reduced P300 amplitudes (P<0.001, respectively). Seventeen of the 100 HCV-infected patients had P300 latencies outside the age-adjusted normal range. Abnormal P300 characteristics were not related to the degree of histologic or biochemical activity of hepatitis, severity of fatigue or mental health impairment. CONCLUSIONS: This study demonstrates that patients with HCV infection showed a slight but significant neurocognitive impairment, possibly indicating a further extrahepatic manifestation of chronic hepatitis C.     

Differential distribution and internal translation efficiency of hepatitis C virus quasispecies present in dendritic and liver cells

Hepatitis C virus (HCV) is predominantly a hepatotropic virus. Nonetheless, there is mounting evidence that hematopoietic cells may support HCV replication. The HCV 5' untranslated region (5'UTR), responsible for initiation of viral translation, via an internal ribosome entry site (IRES), has been previously described to contain specific nucleotide substitutions when cultured in infected lymphoid cells. Our purpose was to establish whether the 5'UTR polymorphism of quasispecies from 3 cell compartments (liver, peripheral blood mononuclear cells [PBMG], and monocyte-derived dendritic cells [DCs]) of a patient chronically infected with HCV1b affects the corresponding translational efficiencies and thus the capacity for replication. The 5'UTR polymorphism was characterized by identification of changes at 3 crucial sites as compared with the reference nucleotide (nt) sequence: a G insertion between positions 19 and 20, a C>A substitution at position 204 and a G>A substitution at position 243. The quasispecies detected in DCs was unique and differed from those present in the liver, suggesting a particular tropism of HCV quasispecies for DCs. Moreover, its translational activity was significantly impaired when compared with those from liver and PBMCs in different cell lines. This impairment was thoroughly confirmed in primary cultures of both human hepatocytes and monocyte-derived DCs. Taken together, our data lend support both to a specific location and impaired replication of HCV quasispecies in DCs, which could be related to viral persistence and perturbation of DC function in chronically infected patients.     

Management of patients with hepatitis C infection and renal disease

Hepatitis C virus(HCV) infection in patients with end-stage renal disease(ESRD) is associated with more rapid liver disease progression and reduced renal graft and patients’ survival following kidney transplantation. Evaluations and management of HCV in patients with renal disease are challenging. The pharmacokinetics of interferons(IFN), ribavirin(RBV) and some direct acting antiviral(DAA), such as sofosbuvir, are altered in patients with ESRD. With dose adjustment and careful monitoring, treatment of HCV in patients with ESRD can be associated with sustained virological response(SVR) rates nearly comparable to that of patients with normal renal function. DAA-based regimens, especially the IFNfree and RBV-free regimens, are theoretically preferred for patients with ESRD and KT in order to increase SVR rates and to reduce treatment side effects. However, based on the data for pharmacokinetics, dosing safety and efficacy of DAA for patients with severe renal impairment are lacking. This review will be focused on the evaluations, available pharmacologic data, and management of HCV in patients with severe renal impairment, patients who underwent KT, and those who suffered from HCV-related renal disease, according to the available treatment options, including DAA.     

Liver stiffness measurements in patients with HBV vs HCV chronic hepatitis: a comparative study

AIM:To assess the values of liver stiffness (LS) in pa-tients with hepatitis B virus (HBV) chronic hepatitis and to compare them with those in patients with hepatitis C virus (HCV) chronic hepatitis. METHODS: The study included 140 patients with HBV chronic hepatitis, and 317 patients with HCV chronic hepatitis, in which LS was measured (FibroScan-Echo-sens) and liver biopsy was performed in the same session (assessed according to the Metavir score). RESULTS:According to the Metavir score of the 140 HBV p...