The etiology of cirrhosis is a strong determinant of brain reserve: A multimodal magnetic resonance imaging study

Excessive intragastric alcohol administration exacerbates hepatic encephalopathy and provokes neuronal cell death in male rats with chronic liver disease

Hepatic encephalopathy (HE) is defined as decline in neurological function during chronic liver disease (CLD). Alcohol is a major etiological factor in the pathogenesis of fibrosis/cirrhosis and has also been documented to directly impact the brain. However, the role of alcohol in the development of HE in CLD remains unclear. Here, we investigated the impact of excessive alcohol administration on neurological deterioration in rats with CLD. Starting day 7 post-BDL surgery, rats were administered alcohol twice daily (51% v/v ethanol, 3 g/kg, via gavage) for 4 weeks. Motor coordination was assessed weekly using rotarod and anxiety-like behavior was evaluated with open field and elevated plus maze at 5 weeks. Upon sacrifice, brains were collected for western blot and immunohistochemical analyses to investigate neuronal integrity and oxidative stress status. Alcohol worsened motor coordination performance and increased anxiety-like behavior in BDL rats. Impairments were associated with decreased neuronal markers of NeuN and SMI311, increased apoptotic markers of cleaved/pro-caspase-3 and Bax/Bcl2, increased necroptosis markers of pRIP3 and pMLKL, decreased total antioxidant capacity (TAC), and increased 4-hydroxynonenal (4-HNE)modified proteins in the cerebellum of BDL-alcohol rats when compared to respective controls. Immunofluorescence confirmed the colocalization of cleaved caspase-3 and pMLKL in the granular neurons of the cerebellum of BDL-alcohol rats. Excessive alcohol consumption exacerbates HE which leads to associated apoptotic and necroptotic neuronal loss in the cerebellum of BDL-alcohol rats. Additionally, higher levels of 4-HNE and decreased TAC in the cerebellum of BDL-alcohol rats suggest oxidative stress is the triggering factor of apoptotic and necroptotic neuronal loss/injury.

Preventing Readmissions of Hepatic Encephalopathy: Strategies in the Acute Inpatient, Immediate Postdischarge, and Longitudinal Outpatient Setting

Hepatic encephalopathy (HE) is a strong predictor of early hospital readmission in patients with cirrhosis. Early hospital readmission increases health care costs and is associated with worse survival. Herein we provide an overview of strategies to prevent hospital readmissions in patients with HE, divided into 3 contexts: (a) acute inpatient, (b) immediate postdischarge, and (c) longitudinal outpatient setting.

[WITHDRAWN] Serum biomarkers of liver fibrosis identify changes in striatal metabolite levels

The full text of this preprint has been withdrawn by the authors due to author disagreement with the posting of the preprint. Therefore, the authors do not wish this work to be cited as a reference. Questions should be directed to the corresponding author.

Improved cognition after rifaximin treatment is associated with changes in intra- and inter-brain network functional connectivity

BACKGROUND

Rifaximin is a non-reabsorbable antibiotic which acts at gut level, and improves cognition and inflammatory parameters in minimal hepatic encephalopathy (MHE) patients, but not all patients show the same level of response. This study aims to assess brain activity, both within and between brain networks, following rifaximin treatment, considering the differences between response groups as well.

METHODS

Twenty-two healthy controls and 53 patients with cirrhosis (22 without and 31 with MHE, diagnosed by Psychometric Hepatic Encephalopathy Score, PHES) performed psychometric, attention and coordination tests, and blood inflammatory parameters were measured. Resting-state functional magnetic resonance imaging (fMRI) acquisitions were performed on controls and MHE patients. Eighteen MHE patients underwent a rifaximin treatment for 6 months, after which all measures were repeated. fMRI images were analysed and changes after treatment were assessed.

RESULTS

After rifaximin treatment, 13 patients improved their PHES score (Responder patients) while 5 did not (Non-responder patients). No significant decrease in blood ammonia was observed after rifaximin treatment, but there was a decrease in plasma inflammatory cytokines in responder patients. A global effect of rifaximin was detected on the sensorimotor and fronto-parietal networks. Responder patients showed a relative increase of thalamic network connectivity in comparison to non-responder patients. Before treatment, responder and non-responder patients showed connectivity differences in basal ganglia network. The connection of the sensorimotor and thalamic networks between them and with other networks suffered changes after treatment. These connections between networks mostly decreased after treatment. All changes and differences showed a significant level of correlation with the performance of psychometric tests and the blood levels of inflammatory biomarkers.

CONCLUSIONS

There was an improvement of the communication between executive, motor and attention-related brain areas, and their functional independence following rifaximin treatment. Patients who respond also show a less deteriorated connection involved in these functions before treatment. Results suggest that the improved inflammatory state of MHE patients, following rifaximin treatment would favour the observed changes in brain function and enhanced cognitive performance.

New insights into the molecular basis of alcohol abstinence and relapse in alcohol-associated liver disease

Alcohol use disorder remains a significant public health concern, affecting around 5% of adults worldwide. Novel pathways of damage have been described during the last years, providing insight into the mechanism of injury due to alcohol misuse beyond the direct effect of ethanol byproducts on the liver parenchyma and neurobehavioral mechanisms. Thus, the gut-liver-brain axis and immune system involvement could be therapeutic targets for alcohol use disorder. In particular, changes in gut microbiota composition and function, and bile acid homeostasis, have been shown with alcohol consumption and cessation. Alcohol can also directly disrupt intestinal and blood-brain barriers. Activation of the immune system can be triggered by intestinal barrier dysfunction and translocation of bacteria, pathogen-associated molecular patterns (such as lipopolysaccharide), cytokines, and damage-associated molecular patterns. These factors, in turn, promote liver and brain inflammation and the progression of liver fibrosis. Other involved mechanisms include oxidative stress, apoptosis, autophagy, and the release of extracellular vesicles and miRNA from hepatocytes. Potential therapeutic targets include gut microbiota (probiotics and fecal microbiota transplantation), neuroinflammatory pathways, as well as neuroendocrine pathways, for example, the ghrelin system (ghrelin receptor blockade), incretin mimetics (glucagon-like peptide-1 analogs), and the mineralocorticoid receptor system (spironolactone). In addition, support with psychological and behavioral treatments is essential to address the multiple dimensions of alcohol use disorder. In the future, a personalized approach considering these novel targets can contribute to significantly decreasing the alcohol-associated burden of disease.

Dynamic evolution of brain structural patterns in liver transplantation recipients: a longitudinal study based on 3D convolutional neuronal network model

OBJECTIVES

To evaluate the dynamic evolution process of overall brain health in liver transplantation (LT) recipients, we employed a deep learning-based neuroanatomic biomarker to measure longitudinal changes of brain structural patterns before and 1, 3, and 6 months after surgery.

METHODS

Because of the ability to capture patterns across all voxels from a brain scan, the brain age prediction method was adopted. We constructed a 3D-CNN model through T1-weighted MRI of 3609 healthy individuals from 8 public datasets and further applied it to a local dataset of 60 LT recipients and 134 controls. The predicted age difference (PAD) was calculated to estimate brain changes before and after LT, and the network occlusion sensitivity analysis was used to determine the importance of each network in age prediction.

RESULTS

The PAD of patients with cirrhosis increased markedly at baseline (+ 5.74 years) and continued to increase within one month after LT (+ 9.18 years). After that, the brain age began to decrease gradually, but it was still higher than the chronological age. The PAD values of the OHE subgroup were higher than those of the no-OHE, and the discrepancy was more obvious at 1-month post-LT. High-level cognition-related networks were more important in predicting the brain age of patients with cirrhosis at baseline, while the importance of primary sensory networks increased temporarily within 6-month post-LT.

CONCLUSIONS

The brain structural patterns of LT recipients showed inverted U-shaped dynamic change in the early stage after transplantation, and the change in primary sensory networks may be the main contributor.

KEY POINTS

• The recipients' brain structural pattern showed an inverted U-shaped dynamic change after LT. • The patients' brain aging aggravated within 1 month after surgery, and the subset of patients with a history of OHE was particularly affected. • The change of primary sensory networks is the main contributor to the change in brain structural patterns.

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.

Specific Challenges in Geriatric Cirrhosis and Hepatic Encephalopathy

As the world's population ages, diseases predominantly found in the elderly now overlap with diseases that were thought to be the purview of younger patients. This includes chronic liver disease, which affects more than 2 billion people worldwide. Owing to the obesity epidemic (and associated metabolic diseases), nonalcoholic fatty liver disease has become the most common cause of chronic liver disease and cirrhosis. A major complication of cirrhosis is hepatic encephalopathy (HE), which becomes challenging to diagnose in elderly patients. HE is usually included in the differential diagnosis of acute delirium but not of reversible dementias. To illustrate this point, we present 2 cases of older patients that were misdiagnosed as having dementia and Parkinson's disease or a parkinsonian syndrome but had contributions from cirrhosis. Both cognitive impairment and tremor resolved with treatment of HE.

Hepatic Encephalopathy and Liver Transplantation: The Past, Present, and Future Toward Equitable Access

Cirrhosis is a debilitating chronic disease with high morbidity and mortality, with the only real cure being liver transplantation (LT). Currently, we allocate organs for transplantation based on the Model for End-Stage Liver Disease-Sodium (MELD-Na) score that does not account for hepatic encephalopathy (HE). HE affects patients, families, and the health care system because of high rates of recurrence and major readmission burden. Moreover, HE casts a long shadow even after LT. Accounting for HE and incorporating it into the current allocation system has many proponents, but the framework to do this is currently lacking because of differences in consensus or in operationalization parameters. We review the latest evidence of the burden of HE, management of HE before and after LT, and evaluate pros and cons of several methods of diagnosing HE objectively to ensure early and equitable access to LT in this underserved population.

The Role of Gut Dysbiosis in Acute-on-Chronic Liver Failure

Acute-on-chronic liver failure (ACLF) is an important syndrome of liver failure that has a high risk of short-term mortality in patients with chronic liver disease. The development of ACLF is associated with proinflammatory precipitating events, such as infection, alcoholic hepatitis, and intense systemic inflammation. Recently, the role of the gut microbiome has increasingly emerged in human health and disease. Additionally, the gut microbiome might have a major role in the development of liver disease. In this review, we examine evidence to support the role of gut dysbiosis in cirrhosis and ACLF. Additionally, we explore the mechanism by which the gut microbiome contributes to the development of ACLF, with a focus on alcohol-induced liver disease.

Evaluation of neurotrophic factors and education level as predictors of cognitive decline in alcohol use disorder

Cognitive reserve (CR) is the capability of an individual to cope with a brain pathology through compensatory mechanisms developed through cognitive stimulation by mental and physical activity. Recently, it has been suggested that CR has a protective role against the initiation of substance use, substance consumption patterns and cognitive decline and can improve responses to treatment. However, CR has never been linked to cognitive function and neurotrophic factors in the context of alcohol consumption. The present cross-sectional study aims to evaluate the association between CR (evaluated by educational level), cognitive impairment (assessed using a frontal and memory loss assessment battery) and circulating levels of brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) in patients with alcohol use disorder (AUD). Our results indicated that lower educational levels were accompanied by earlier onset of alcohol consumption and earlier development of alcohol dependence, as well as impaired frontal cognitive function. They also suggest that CR, NT-3 and BDNF may act as compensatory mechanisms for cognitive decline in the early stages of AUD, but not in later phases. These parameters allow the identification of patients with AUD who are at risk of cognitive deterioration and the implementation of personalized interventions to preserve cognitive function.

Focused Education Increases Hepatocellular Cancer Screening in Patients with Cirrhosis Regardless of Functional Health Literacy

BACKGROUND

Health education interventions are successful in modifying lifestyle. Functional health literacy (FHL) can determine patient adherence to clinic visits and procedures and may adversely impact the success of these interventions.

AIMS

We sought to evaluate the hypothesis that a health education intervention would improve compliance with hepatocellular cancer (HCC) screening and that poor FHL would reduce such compliance.

METHODS

We assessed FHL using a short version test of functional health literacy in adults (STOFHLA). Cirrhotic patients free of HCC were prospectively enrolled from clinics and provided an educational intervention consisting of focused physician-led discussion regarding cirrhosis and HCC, along with written material on these topics for the subject to review at home. Patients were subsequently followed for 6 months (prospective time period), and the same cohort's clinic/HCC screening behavior between 6 and 12 months prior to the educational intervention (retrospective time period) was compared.

RESULTS

In total, 104 cirrhotic patients (age 60.01 ± 8.58 years, 80% men, MELD 12.70 ± 5.76) were included. Of these, 89 (85.57%) of patients had educational level 12th grade and higher. There were 76% (n = 79) with adequate, while 24% (n = 25) had inadequate/marginal FHL on S-TOHFLA. The number of HCC-related imaging increased from 59 (56.7%) to 86 (82.6%, p < 0.0001) post-education in the prospective compared to prior time period which was similar regardless of FHL.

CONCLUSIONS

While the educational intervention was successful in improving compliance with HCC screenings, FHL status did not impact the power of this intervention. Hence, the combination of specific verbal information, along with targeted written material, improved compliance with clinic visits and liver imaging for HCC.

Hepatic Encephalopathy: From Metabolic to Neurodegenerative

Hepatic encephalopathy (HE) is a neuropsychiatric syndrome of both acute and chronic liver disease. As a metabolic disorder, HE is considered to be reversible and therefore is expected to resolve following the replacement of the diseased liver with a healthy liver. However, persisting neurological complications are observed in up to 47% of transplanted patients. Several retrospective studies have shown that patients with a history of HE, particularly overt-HE, had persistent neurological complications even after liver transplantation (LT). These enduring neurological conditions significantly affect patient's quality of life and continue to add to the economic burden of chronic liver disease on health care systems. This review discusses the journey of the brain through the progression of liver disease, entering the invasive surgical procedure of LT and the conditions associated with the post-transplant period. In particular, it will discuss the vulnerability of the HE brain to peri-operative factors and post-LT conditions which may explain non-resolved neurological impairment following LT. In addition, the review will provide evidence; (i) supporting overt-HE impacts on neurological complications post-LT; (ii) that overt-HE leads to permanent neuronal injury and (iii) the pathophysiological role of ammonia toxicity on astrocyte and neuronal injury/damage. Together, these findings will provide new insights on the underlying mechanisms leading to neurological complications post-LT.

Role of bile acids in liver diseases mediated by the gut microbiome

The intensive crosstalk between the liver and the intestine performs many essential functions. This crosstalk is important for natural immune surveillance, adaptive immune response regulation and nutrient metabolism and elimination of toxic bacterial metabolites. The interaction between the gut microbiome and bile acids is bidirectional. The gut microbiome regulates the synthesis of bile acids and their biological signaling activity and circulation via enzymes. Similarly, bile acids also shape the composition of the gut microbiome by modulating the host’s natural antibacterial defense and the intestinal immune system. The interaction between bile acids and the gut microbiome has been implicated in the pathophysiology of many intestinal and extra intestinal diseases, especially liver diseases. As essential mediators of the gut-liver crosstalk, bile acids regulate specific host metabolic pathways and modulate the inflammatory responses through farnesoid X-activated receptor and G protein-coupled bile acid receptor 1. Several clinical trials have demonstrated the signaling effects of bile acids in the context of liver diseases. We hypothesize the existence of a gut microbiome-bile acids-liver triangle and explore the potential therapeutic strategies for liver diseases targeting the triangle.

Gut Microbiota at the Intersection of Alcohol, Brain, and the Liver

Over the last decade, increased research into the cognizance of the gut-liver-brain axis in medicine has yielded powerful evidence suggesting a strong association between alcoholic liver diseases (ALD) and the brain, including hepatic encephalopathy or other similar brain disorders. In the gut-brain axis, chronic, alcohol-drinking-induced, low-grade systemic inflammation is suggested to be the main pathophysiology of cognitive dysfunctions in patients with ALD. However, the role of gut microbiota and its metabolites have remained unclear. Eubiosis of the gut microbiome is crucial as dysbiosis between autochthonous bacteria and pathobionts leads to intestinal insult, liver injury, and neuroinflammation. Restoring dysbiosis using modulating factors such as alcohol abstinence, promoting commensal bacterial abundance, maintaining short-chain fatty acids in the gut, or vagus nerve stimulation could be beneficial in alleviating disease progression. In this review, we summarize the pathogenic mechanisms linked with the gut-liver-brain axis in the development and progression of brain disorders associated with ALD in both experimental models and humans. Further, we discuss the therapeutic potential and future research directions as they relate to the gut-liver-brain axis.

Role of gut microbiota via the gut-liver-brain axis in digestive diseases

The gut-brain axis is a bidirectional information interaction system between the central nervous system (CNS) and the gastrointestinal tract, in which gut microbiota plays a key role. The gut microbiota forms a complex network with the enteric nervous system, the autonomic nervous system, and the neuroendocrine and neuroimmunity of the CNS, which is called the microbiota-gut-brain axis. Due to the close anatomical and functional interaction of the gut-liver axis, the microbiota-gut-liver-brain axis has attracted increased attention in recent years. The microbiota-gut-liver-brain axis mediates the occurrence and development of many diseases, and it offers a direction for the research of disease treatment. In this review, we mainly discuss the role of the gut microbiota in the irritable bowel syndrome, inflammatory bowel disease, functional dyspepsia, non-alcoholic fatty liver disease, alcoholic liver disease, cirrhosis and hepatic encephalopathy via the gut-liver-brain axis, and the focus is to clarify the potential mechanisms and treatment of digestive diseases based on the further understanding of the microbiota-gut- liver-brain axis.

Transjugular intrahepatic portosystemic shunt for patients with liver cirrhosis: survey evaluating indications, standardization of procedures and anticoagulation in 43 German hospitals

OBJECTIVES

Transjugular intrahepatic portosystemic shunt (TIPS) insertion is an established treatment to lower portal pressure. There are no obligatory evidence-based recommendations addressing procedure and anticoagulation. Therefore, a survey was performed to establish current practice at different German hospitals.

METHODS

A three-page survey was sent out via postal mail to 76 different hospitals addressing the topics indication, contraindication, follow-up and anticoagulation.

RESULTS

Forty-three hospitals completed the survey: the median number of TIPS/year was 28.6 ± 23. Ascites and hydrothorax were announced as the main indications. Bilirubin levels above 5 mg/dl, hepatic encephalopathy and cardiac disease were considered as absolute contraindications in most hospitals, but age was not. The biggest variations were reported with regard to anticoagulation after TIPS procedure. Four hospitals never used any anticoagulation; most hospitals reported the use of low molecular weight heparins for a period of days up to 4 weeks. But also aspirin or clopidogrel was used after TIPS insertion in eight different hospitals. Additionally, the standards for follow-up after TIPS insertion were different in the hospitals.

CONCLUSIONS

There is no consensus how to handle indication, contraindications and anticoagulation after the TIPS procedure. A national and international consensus is warranted to improve the outcome of TIPS patients and reduce secondary complications. In addition to compare results and efficacy in the future standard operation procedures as proposed here need to be put in place.

Alcohol use disorders and the brain

A diagnosis of alcohol use disorder is associated with a higher risk of dementia, but a dose-response relationship between alcohol intake consumption and cognitive impairment remains unclear. Alcohol is associated with a range of effects on the central nervous system at different doses and acts on a number of receptors. Acute disorders include Wernicke's encephalopathy (WE), traumatic brain injury, blackouts, seizures, stroke and hepatic encephalopathy. The most common manifestations of chronic alcohol consumption are Korsakoff's syndrome (KS) and alcohol-related dementia (ARD). There is limited evidence for benefit from memantine in the treatment of ARD, but stronger evidence for the use of high-dose parenteral thiamine in the progression of neuropsychiatric symptoms for WE. Accumulating evidence exists for pharmacological treatment in the prevention of hepatic encephalopathy. Rehabilitation of people with ARD may take several years, and requires an approach that addresses physical and psychosocial factors.

Cognitive Function in Liver Transplantation

PURPOSE OF REVIEW

Liver transplantation (LT) remains the only way to cure patients with severe liver diseases. Important questions about neurological sequelae and quality of life after LT have emerged. In this review, we discuss the neurocognitive changes associated with LT and we conclude with recommendations in this regard for patients, caregivers, and physicians.

RECENT FINDINGS

Compared with other solid organ recipients, LT patients tend to have a higher incidence (up to 30%) of neurological complications post-LT. Even in absence of previous episodes of hepatic encephalopathy (HE), some patients display new onset of neurological symptoms post-LT, raising the concern about the role of other factors that may have a direct impact on cognitive function.

SUMMARY

Different mechanisms have been postulated to explain these postoperative neurological symptoms. They include sequelae of HE, persistent impairment of cognitive function due to cirrhosis, or postoperative decompensation of an unknown or undiagnosed neurodegenerative disorder.

Cerebral metabolite alterations in patients with posttransplant encephalopathy after liver transplantation

Background

In the first weeks after liver transplantation about 30% of the patients develop a posttransplant encephalopathy. A posttransplant encephalopathy comprises metabolic-toxic caused symptoms such as disorientation, confusion, hallucinations, cognitive dysfunction and seizures. We hypothesize that alterations of cerebral metabolites before liver transplantation predispose posttransplant encephalopathy development after liver transplantation.

Methods

31 patients with chronic liver disease underwent magnetic resonance spectroscopy (MRS) before liver transplantation to assess glutamine/glutamate (Glx), myo-Inositol (mI), choline (Cho), creatine/phosphocreatine- and N-acetyl-aspartate/N-acetyl-aspartate-glutamate concentrations in the thalamus, lentiform nucleus and white matter. Of these, 14 patients underwent MRS additionally after liver transplantation. Furthermore, 15 patients received MRS only after liver transplantation. Patients’ data were compared to 20 healthy age adjusted controls.

Results

Patients showed significantly increased Glx and decreased mI and Cho concentrations compared to controls before liver transplantation (p≤0.01). The MRS values before liver transplantation of patients with posttransplant encephalopathy showed no significant difference compared to patients without posttransplant encephalopathy. Patients after liver transplantation showed increased Glx concentrations (p≤0.01) compared to controls, however, patients with and without posttransplant encephalopathy did not differ. Patients with posttransplant encephalopathy who underwent MRS before and after liver transplantation showed a significant mI increase in all three brain regions (p<0.04) and Glx decrease in the lentiform nucleus after liver transplantation (p = 0.04) while patients without posttransplant encephalopathy only showed a mI increase in the thalamus (p = 0.04).

Conclusion

Patients with and without posttransplant encephalopathy showed no significant difference in cerebral metabolites before liver transplantation. However, the paired sub-analysis indicates that the extent of cerebral metabolite alterations in patients with liver cirrhosis might be critical for the development of posttransplant encephalopathy after liver transplantation.

Targeting Microbiota: What Do We Know about It at Present?

The human microbiota is a variety of different microorganisms. The composition of microbiota varies from host to host, and it changes during the lifetime. It is known that microbiome may be changed because of a diet, bacteriophages and different processes for example, such as inflammation. Like all other areas of medicine, there is a continuous growth in the area of microbiology. Different microbes can reside in all sites of a human body, even in locations that were previously considered as sterile; for example, liver, pancreas, brain and adipose tissue. Presently one of the etiological factors for liver disease is considered to be pro-inflammatory changes in a host’s organism. There are lot of supporting data about intestinal dysbiosis and increased intestinal permeability and its effect on development of liver disease pointing to the gut–liver axis. The gut–liver axis affects pathogenesis of many liver diseases, such as chronic hepatitis B, chronic hepatitis C, alcoholic liver disease, non-alcoholic liver disease, non-alcoholic steatohepatitis, liver cirrhosis and hepatocellular carcinoma. Gut microbiota has been implicated in the regulation of brain health, emphasizing the gut–brain axis. Also, experiments with mice showed that microorganisms have significant effects on the blood–brain barrier integrity. Microbiota can modulate a variety of mechanisms through the gut–liver axis and gut–brain axis. Normal intestinal flora impacts the health of a host in many positive ways, but there is now significant evidence that intestinal microbiota, especially altered, have the ability to impact the pathologies of many diseases through different inflammatory mechanisms. At this point, many of the pathophysiological reactions in case of microbial disbyosis are still unclear.

Neuroimaging in alcohol use disorder: From mouse to man

This article provides an overview of recent advances in understanding the effects of alcohol use disorders (AUD) on the brain from the perspective of magnetic resonance imaging (MRI) research in preclinical models and clinical studies. As a noninvasive investigational tool permitting assessment of morphological, metabolic, and hemodynamic changes over time, MRI offers insight into the dynamic course of alcoholism beginning with initial exposure through periods of binge drinking and escalation, sobriety, and relapse and has been useful in differential diagnosis of neurological diseases associated with AUD. Structural MRI has revealed acute and chronic effects of alcohol on both white and gray matter volumes. MR Spectroscopy, able to quantify brain metabolites in vivo, has shed light on biochemical alterations associated with alcoholism. Diffusion tensor imaging permits microstructural characterization of white matter fiber tracts. Functional MRI has allowed for elucidation of hemodynamic responses at rest and during task engagement. Positron emission tomography, a non-MRI imaging tool, has led to a deeper understanding of alcohol-induced receptor and neurotransmitter changes during various stages of drinking and abstinence. Together, such in vivo imaging tools have expanded our understanding of the dynamic course of alcoholism including evidence for regional specificity of the effects of AUD, hints at mechanisms underlying the shift from casual to compulsive use of alcohol, and profound recovery with sustained abstinence.

Alcohol, liver disease and the gut microbiota

Alcoholic liver disease, which ranges from mild disease to alcoholic hepatitis and cirrhosis, is a leading cause of morbidity and mortality worldwide. Alcohol intake can lead to changes in gut microbiota composition, even before liver disease development. These alterations worsen with advancing disease and could be complicit in disease progression. Microbial function, especially related to bile acid metabolism, can modulate alcohol-associated injury even in the presence of cirrhosis and alcoholic hepatitis. Microbiota changes might also alter brain function, and the gut-brain axis might be a potential target to reduce alcoholic relapse risk. Gut microbiota manipulation including probiotics, faecal microbial transplant and antibiotics has been studied in alcoholic liver disease with varying success. Further investigation of the modulation of the gut-liver axis is relevant, as most of these patients are not candidates for liver transplantation. This Review focuses on clinical studies involving the gut microbiota in patients with alcoholic liver disease across the spectrum from alcoholic fatty liver to cirrhosis and alcoholic hepatitis. Specific alterations in the gut-liver-brain axis that are complicit in the interactions between the gut microbiota and alcohol addiction are also reviewed.

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.

Brain Edema in Chronic Hepatic Encephalopathy

Brain edema is a common feature associated with hepatic encephalopathy (HE). In patients with acute HE, brain edema has been shown to play a crucial role in the associated neurological deterioration. In chronic HE, advanced magnetic resonance imaging (MRI) techniques have demonstrated that low-grade brain edema appears also to be an important pathological feature. This review explores the different methods used to measure brain edema ex vivo and in vivo in animal models and in humans with chronic HE. In addition, an in-depth description of the main studies performed to date is provided. The role of brain edema in the neurological alterations linked to HE and whether HE and brain edema are the manifestations of the same pathophysiological mechanism or two different cerebral manifestations of brain dysfunction in liver disease are still under debate. In vivo MRI/magnetic resonance spectroscopy studies have allowed insight into the development of brain edema in chronic HE. However, additional in vivo longitudinal and multiparametric/multimodal studies are required (in humans and animal models) to elucidate the relationship between liver function, brain metabolic changes, cellular changes, cell swelling, and neurological manifestations in chronic HE.

Highlighting the Role of Cognitive and Brain Reserve in the Substance use Disorder Field

BACKGROUND

Cognitive reserve (CR) refers to the ability of an individual to cope with brain pathology remaining free of cognitive symptoms. This protective factor has been related to compensatory and more efficient brain mechanisms involved in resisting brain damage. For its part, Brain reserve (BR) refers to individual differences in the structural properties of the brain which could also make us more resilient to suffer from neurodegenerative and mental diseases.

OBJECTIVE

This review summarizes how this construct, mainly mediated by educational level, occupational attainment, physical and mental activity, as well as successful social relationships, has gained scientific attention in the last years with regard to diseases, such as neurodegenerative diseases, stroke or traumatic brain injury. Nevertheless, although CR has been studied in a large number of disorders, few researches have addressed the role of this concept in drug addiction.

METHODS

We provide a selective overview of recent literature about the role of CR and BR in preventing substance use onset. Likewise, we will also discuss how variables involved in CR (healthy leisure, social support or job-related activities, among others) could be trained and included as complementary activities of substance use disorder treatments.

RESULTS

Evidence about this topic suggests a preventive role of CR and BR on drug use onset and when drug addiction is established, these factors led to less severe addiction-related problems, as well as better treatment outcomes.

CONCLUSION

CR and BR are variables not taken yet into account in drug addiction. However, they could give us a valuable information about people at risk, as well as patient's prognosis.

Decreased Taurine and Creatine in the Thalamus May Relate to Behavioral Impairments in Ethanol-Fed Mice: A Pilot Study of Proton Magnetic Resonance Spectroscopy

Minimal hepatic encephalopathy (MHE) is highly prevalent, observed in up to 80% of patients with liver dysfunction. Minimal hepatic encephalopathy is defined as hepatic encephalopathy with cognitive deficits and no grossly evident neurologic abnormalities. Clinical management may be delayed due to the lack of in vivo quantitative methods needed to reveal changes in brain neurobiochemical biomarkers. To gain insight into the development of alcoholic liver disease–induced neurological dysfunction (NDF), a mouse model of late-stage alcoholic liver fibrosis (LALF) was used to investigate changes in neurochemical levels in the thalamus and hippocampus that relate to behavioral changes. Proton magnetic resonance spectroscopy of the brain and behavioral testing were performed to determine neurochemical alterations and their relationships to behavioral changes in LALF. Glutamine levels were higher in both the thalamus and hippocampus of alcohol-treated mice than in controls. Thalamic levels of taurine and creatine were significantly diminished and strongly correlated with alcohol-induced behavioral changes. Chronic long-term alcohol consumption gives rise to advanced liver fibrosis, neurochemical changes in the nuclei, and behavioral changes which may be linked to NDF. Magnetic resonance spectroscopy represents a sensitive and noninvasive measurement of pathological alterations in the brain, which may provide insight into the pathogenesis underlying the development of MHE.

Combined diffusion tensor imaging and magnetic resonance spectroscopy to predict neurological outcome before transjugular intrahepatic portosystemic shunt

BACKGROUND

Hepatic encephalopathy (HE) may occur after transjugular intrahepatic portosystemic shunt (TIPSS) placement. Multimodal magnetic resonance imaging (MRI), combining anatomical sequences, diffusion tensor imaging (DTI) and ¹ H magnetic resonance spectroscopy, is modified in cirrhotic patients.

AIMS

To describe multimodal MRI images before TIPSS, to assess if TIPSS induces changes in multimodal MRI, and to find predictors of HE after TIPSS in patients with cirrhosis.

METHODS

Consecutive cirrhotic patients with an indication for TIPSS were prospectively screened. Diagnosis of minimal HE was performed using psychometric HE test score. Multimodal MRI was performed before and 3 months after TIPSS placement.

RESULTS

Twenty-five consecutive patients were analysed (median age = 59, male gender 76%, median Child-Pugh score = 8 [5-8], MELD score = 12 [9-17], indication for TIPSS placement: ascites/secondary prophylaxis of variceal bleeding/other 20/3/2), no HE/minimal HE/overt HE: 21/4/0. 8/25 patients developed HE after TIPSS. Before TIPSS placement, metabolite concentrations were different in patients with or without minimal HE (lower myo-inositol, mI, higher glutamate/glutamine), but there were no differences in DTI data. TIPSS placement induced changes in metabolite concentrations even in asymptomatic patients, but not in DTI metrics. Baseline fractional anisotropy was significantly lower in patients who developed HE after TIPSS in five regions of interest.

CONCLUSIONS

TIPSS placement induced significant changes in cerebral metabolites, even in asymptomatic patients. Patients who developed HE after TIPSS displayed lower fractional anisotropy before TIPSS. Brain MRI with DTI acquisition may help selecting patients at risk of HE.

Gut microbial RNA and DNA analysis predicts hospitalizations in cirrhosis

BACKGROUND

Cirrhosis is associated with gut microbial changes, but current 16S rDNA techniques sequence both dead and live bacteria. We aimed to determine the rRNA content compared with DNA from the same stool sample to evaluate cirrhosis progression and predict hospitalizations.

METHODS

Cirrhotics and controls provided stool for RNA and DNA analysis. Comparisons were made between cirrhotics/controls and within cirrhosis (compensated/decompensated, infected/uninfected, renal dysfunction/not, rifaximin use/not) with respect to DNA and RNA bacterial content using linear discriminant analysis. A separate group was treated with omeprazole for 14 days with longitudinal microbiota evaluation. Patients were followed for 90 days for hospitalizations. Multivariable models for hospitalizations with clinical data with and without DNA and RNA microbial data were created.

RESULTS

Twenty-six controls and 154 cirrhotics (54 infected, 62 decompensated, 20 renal dysfunction, 18 rifaximin) were included. RNA and DNA analysis showed differing potentially pathogenic taxa but similar autochthonous taxa composition. Thirty subjects underwent the omeprazole study, which demonstrated differences between RNA and DNA changes. Thirty-six patients were hospitalized within 90 days. In the RNA model, MELD score and Enterococcus were independently predictive of hospitalizations, while in the DNA model MELD was predictive and Roseburia protective. In both models, adding microbiota significantly added to the MELD score in predicting hospitalizations.

CONCLUSION

DNA and RNA analysis of the same stool sample demonstrated differing microbiota composition, which independently predicts the hospitalization risk in cirrhosis. RNA and DNA content of gut microbiota in cirrhosis are modulated differentially with disease severity, infections, and omeprazole use.

TRIAL REGISTRATION

NCT01458990.

FUNDING

VA Merit I0CX001076.

Effects of Alcohol on the Brain in Cirrhosis: Beyond Hepatic Encephalopathy

Recent advances have led to a greater understanding of how alcohol alters the brain, both in acute stages (intoxication and alcohol withdrawal) and in chronic misuse. This review focuses on the current understanding of how alcohol affects the brain in cirrhosis patients with and without hepatic encephalopathy (HE). Chronic alcohol use is associated with nutritional deficiencies, dementia, cirrhosis, and decompensating events such as HE. Direct toxicity on brain tissue, induction of neuro-inflammation, and alcohol's alterations of the gut microbiome are possible mechanisms for the clinical features of HE associated with alcohol use. Acute management of the alcoholic cirrhosis patient with altered mental status should focus on ruling out other causes, best intensive care, and use of gut-based therapies such as lactulose and rifaximin. Long-term management centers on optimizing treatment of concurrent mood disorders, nutritional support, and medical management of complications associated with cirrhosis. Future studies are needed to clarify mechanisms of brain injury in concomitant alcohol misuse and HE in addition to designing treatment interventions in order to improve outcomes in these patients.

Fecal microbiota transplant from a rational stool donor improves hepatic encephalopathy: A randomized clinical trial

Recurrent hepatic encephalopathy (HE) is a leading cause of readmission despite standard of care (SOC) associated with microbial dysbiosis. Fecal microbiota transplantation (FMT) may improve dysbiosis; however, it has not been studied in HE. We aimed to define whether FMT using a rationally derived stool donor is safe in recurrent HE compared to SOC alone. An open-label, randomized clinical trial with a 5-month follow-up in outpatient men with cirrhosis with recurrent HE on SOC was conducted with 1:1 randomization. FMT-randomized patients received 5 days of broad-spectrum antibiotic pretreatment, then a single FMT enema from the same donor with the optimal microbiota deficient in HE. Follow-up occurred on days 5, 6, 12, 35, and 150 postrandomization. The primary outcome was safety of FMT compared to SOC using FMT-related serious adverse events (SAEs). Secondary outcomes were adverse events, cognition, microbiota, and metabolomic changes. Participants in both arms were similar on all baseline criteria and were followed until study end. FMT with antibiotic pretreatment was well tolerated. Eight (80%) SOC participants had a total of 11 SAEs compared to 2 (20%) FMT participants with SAEs (both FMT unrelated; P = 0.02). Five SOC and no FMT participants developed further HE (P = 0.03). Cognition improved in the FMT, but not the SOC, group. Model for End-Stage Liver Disease (MELD) score transiently worsened postantibiotics, but reverted to baseline post-FMT. Postantibiotics, beneficial taxa, and microbial diversity reduction occurred with Proteobacteria expansion. However, FMT increased diversity and beneficial taxa. SOC microbiota and MELD score remained similar throughout.

CONCLUSION

FMT from a rationally selected donor reduced hospitalizations, improved cognition, and dysbiosis in cirrhosis with recurrent HE. (Hepatology 2017;66:1727-1738).

Cognitive reserve is a resilience factor for cognitive dysfunction in hepatic encephalopathy

Cognitive Reserve (CR) modulates symptoms of brain disease. The aim of this study was: to evaluate the effect of CR on cognition in cirrhosis and on the mismatch between cognitive and neurophysiologic assessment of hepatic encephalopathy (HE). Eighty-two outpatient patients with cirrhosis without overt HE were studied [73% males; age: 62 (54-68) (median, interq. range) yrs.; education: 8 (6-13) yrs.]. The Psychometric Hepatic Encephalopathy Score (PHES) was used as cognitive measure of HE. The spectral analysis of the electroencephalogram (EEG) was used as neurophysiologic measure of HE. The CR was assessed by the CR Index (CRI), which was measured by the CRI questionnaire (CRIq) ( http://cri.psy.unipd.it ). The PHES was altered in 28% of patients and the EEG in 41%. Altered PHES was related to the severity of cirrhosis as assessed by Child-Pugh classification (R = 0.31, p < 0.005). Patients with maintained PHES had higher CRI than those with altered PHES (CRI = 100 ± 20 vs. 88 ± 12 vs., p < 0.01), but not the ones with normal EEG compared to those with abnormal EEG (CRI = 96 ± 17 vs. 98 ± 17 vs. p: n.s.).The PHES, but not the EEG, was found to be related to the CRI (r = 0.35, p < 0.01). The mismatch between cognitive and neurophysiologic evaluation of non-overt HE (the ratio between PHES and the mean dominant frequency -MDF- of the EEG i.e., cognitive performance normalized by EEG speed) was found to be correlated to the CRI (r = 0.36, p < 0.005). CR is a resilience factor for cognitive dysfunction in cirrhosis, and is easily measurable by CRIq.

Hepatic Encephalopathy Is Associated with Persistent Learning Impairments Despite Adequate Medical Treatment: A Multicenter, International Study

BACKGROUND

Hepatic encephalopathy (HE) is considered reversible regarding mental status but may not be cognitively in single-center studies.

AIM

To evaluate persistence of learning impairment in prior HE compared to those who never experienced HE (no-HE) in a multicenter study.

METHODS

A total of 174 outpatient cirrhotics from three centers (94 Virginia, 30 Ohio, and 50 Rome; 36 prior HE) underwent psychometric hepatic encephalopathy score (PHES) and inhibitory control (ICT) testing at baseline and then at least 7 days apart. ICT learning (change in 2nd half lures compared to 1st half) was compared between patient groups at both visits. Change in the PHES individual sub-tests and total score between visits was compared in both groups. US versus Italian trends were also analyzed.

RESULTS

HE patients had worse PHES and ICT results compared to no-HE patients at baseline. Significant improvement (1st half 7.1 vs. 2nd half 6.2, p < 0.0001) was observed in no-HE, but not in HE (1st half 7.9 vs. 2nd half 7.8, p = 0.1) at baseline. At retesting (median 20 days later), no-HE patients continued with significant learning (1st half 6.0 vs. 2nd half 5.4, p < 0.0001), while HE patients again did not improve (1st half 7.8 vs. 2nd half 6.9, p = 0.37). Between visits, no-HE patients improved significantly on four PHES sub-tests and overall score, while HE patients only improved on two sub-tests with similar overall PHES score. Trends were similar between US and Italian subjects.

CONCLUSION

In this multicenter study, prior HE patients showed persistent significant learning impairment compared to those without prior HE, despite adequate medical therapy. This persistent change should increase efforts to reduce the first HE episode.

A longitudinal study of patients with cirrhosis treated with L-ornithine L-aspartate, examined with magnetization transfer, diffusion-weighted imaging and magnetic resonance spectroscopy

The presence of overt hepatic encephalopathy (HE) is associated with structural, metabolic and functional changes in the brain discernible by use of a variety of magnetic resonance (MR) techniques. The changes in patients with minimal HE are less well documented. Twenty-two patients with well-compensated cirrhosis, seven of whom had minimal HE, were examined with cerebral 3 Tesla MR techniques, including T₁- and T₂-weighted, magnetization transfer and diffusion-weighted imaging and proton magnetic resonance spectroscopy sequences. Studies were repeated after a 4-week course of oral L-ornithine L-aspartate (LOLA). Results were compared with data obtained from 22 aged-matched healthy controls. There was no difference in mean total brain volume between patients and controls at baseline. Mean cerebral magnetization transfer ratios were significantly reduced in the globus pallidus and thalamus in the patients with cirrhosis irrespective of neuropsychiatric status; the mean ratio was significantly reduced in the frontal white matter in patients with minimal HE compared with healthy controls but not when compared with their unimpaired counterparts. There were no significant differences in either the median apparent diffusion coefficients or the mean fractional anisotropy, calculated from the diffusion-weighted imaging, or in the mean basal ganglia metabolite ratios between patients and controls. Psychometric performance improved in 50 % of patients with minimal HE following LOLA, but no significant changes were observed in brain volumes, cerebral magnetization transfer ratios, the diffusion weighted imaging variables or the cerebral metabolite ratios. MR variables, as applied in this study, do not identify patients with minimal HE, nor do they reflect changes in psychometric performance following LOLA.

Transjugular Intrahepatic Portosystemic Shunts in Patients with Cirrhosis with Refractory Ascites: Comparison of Clinical Outcomes by Using 8- and 10-mm PTFE-covered Stents

Purpose To compare the efficacy and complications of transjugular intrahepatic portosystemic shunt (TIPS) creation performed by using a 10-mm or an 8-mm-diameter polytetrafluoroethylene (PTFE)-covered stent in a consecutive series of patients with cirrhosis with refractory ascites (RA). Materials and Methods The institutional review board approved this retrospective study and informed consent was waived. One hundred seventy-one patients with RA (mean age, 58.7 years ± 10.3; 95% confidence interval [CI]: 57.2 years, 60.3 years) had undergone TIPS placement by using 10-mm (60 patients) or 8-mm (111 patients) covered stent between January 2004 and December 2012. Median follow-up time was 16.8 months (range, 3.4-84.8 months). Hemodynamic changes, incidence of hepatic encephalopathy, and long-term (>3 months) need for paracentesis after TIPS placement were evaluated and calculated by using the Kaplan-Meier method and were compared by using the log-rank test. Results Pre-TIPS demographics and clinical characteristics of the two groups were comparable. The portosystemic gradient before TIPS was 17.0 mm Hg ± 4.2 (95% CI: 15.9 mm Hg, 18.1 mm Hg) in the 10-mm group versus 16.1 mm Hg ± 3.7 (95% CI: 15.4 mm Hg, 16.8 mm Hg) in the 8-mm group (P = .164). After TIPS, the portosystemic gradient was 6.5 mm Hg ± 3.4 (95% CI: 5.7 mm Hg, 7.4 mm Hg) in the 10-mm group versus 7.5 mm Hg ± 2.6 (95% CI: 6.9 mm Hg, 7.9 mm Hg) in the 8-mm group (P = .039). The long-term need for paracentesis was greater in the 8-mm group (64 of 111 patients [58%] vs 18 of 60 patients [31%], P = .003). Overall, hepatic encephalopathy was similar in both groups (45 of 111 patients [41%] vs 26 of 60 patients [44%], P = .728). Conclusion A10-mm PTFE-covered stent leads to better control of RA secondary to portal hypertension in patients with cirrhosis, compared with an 8-mm stent, without increasing the incidence of hepatic encephalopathy. ^© RSNA, 2017.

Alcohol's Effects on the Brain: Neuroimaging Results in Humans and Animal Models

Brain imaging technology has allowed researchers to conduct rigorous studies of the dynamic course of alcoholism through periods of drinking, sobriety, and relapse and to gain insights into the effects of chronic alcoholism on the human brain. Magnetic resonance imaging (MRI) studies have distinguished alcohol-related brain effects that are permanent from those that are reversible with abstinence. In support of postmortem neuropathological studies showing degeneration of white matter, MRI studies have shown a specific vulnerability of white matter to chronic alcohol exposure. Such studies have demonstrated white-matter volume deficits as well as damage to selective gray-matter structures. Diffusion tensor imaging (DTI), by permitting microstructural characterization of white matter, has extended MRI findings in alcoholics. MR spectroscopy (MRS) allows quantification of several metabolites that shed light on brain biochemical alterations caused by alcoholism. This article focuses on MRI, DTI, and MRS findings in neurological disorders that commonly co-occur with alcoholism, including Wernicke's encephalopathy, Korsakoff's syndrome, and hepatic encephalopathy. Also reviewed are neuroimaging findings in animal models of alcoholism and related neurological disorders. This report also suggests that the dynamic course of alcoholism presents a unique opportunity to examine brain structural and functional repair and recovery.

Pathological Predictors of Shunt Stenosis and Hepatic Encephalopathy after Transjugular Intrahepatic Portosystemic Shunt

Background. Transjugular intrahepatic portosystemic shunt (TIPS) is an artificial channel from the portal vein to the hepatic vein or vena cava for controlling portal vein hypertension. The major drawbacks of TIPS are shunt stenosis and hepatic encephalopathy (HE); previous studies showed that post-TIPS shunt stenosis and HE might be correlated with the pathological features of the liver tissues. Therefore, we analyzed the pathological predictors for clinical outcome, to determine the risk factors for shunt stenosis and HE after TIPS. Methods. We recruited 361 patients who suffered from portal hypertension symptoms and were treated with TIPS from January 2009 to December 2012. Results. Multivariate logistic regression analysis showed that the risk of shunt stenosis was increased with more severe inflammation in the liver tissue (OR, 2.864; 95% CI: 1.466–5.592; P = 0.002), HE comorbidity (OR, 6.266; 95% CI, 3.141–12.501; P < 0.001), or higher MELD score (95% CI, 1.298–1.731; P < 0.001). Higher risk of HE was associated with shunt stenosis comorbidity (OR, 6.266; 95% CI, 3.141–12.501; P < 0.001), higher stage of the liver fibrosis (OR, 2.431; 95% CI, 1.355–4.359; P = 0.003), and higher MELD score (95% CI, 1.711–2.406; P < 0.001). Conclusion. The pathological features can predict individual susceptibility to shunt stenosis and HE.