Hepatic Encephalopathy: From the Pathogenesis to the New Treatments

Role of fecal microbiota transplant in management of hepatic encephalopathy: Current trends and future directions

Fecal microbiota transplantation (FMT) offers a potential treatment avenue for hepatic encephalopathy (HE) by leveraging beneficial bacterial displacement to restore a balanced gut microbiome. The prevalence of HE varies with liver disease severity and comorbidities. HE pathogenesis involves ammonia toxicity, gut-brain communication disruption, and inflammation. FMT aims to restore gut microbiota balance, addressing these factors. FMT's efficacy has been explored in various conditions, including HE. Studies suggest that FMT can modulate gut microbiota, reduce ammonia levels, and alleviate inflammation. FMT has shown promise in alcohol-associated, hepatitis B and C-associated, and non-alcoholic fatty liver disease. Benefits include improved liver function, cognitive function, and the slowing of disease progression. However, larger, controlled studies are needed to validate its effectiveness in these contexts. Studies have shown cognitive improvements through FMT, with potential benefits in cirrhotic patients. Notably, trials have demonstrated reduced serious adverse events and cognitive enhancements in FMT arms compared to the standard of care. Although evidence is promising, challenges remain: Limited patient numbers, varied dosages, administration routes, and donor profiles. Further large-scale, controlled trials are essential to establish standardized guidelines and ensure FMT's clinical applications and efficacy. While FMT holds potential for HE management, ongoing research is needed to address these challenges, optimize protocols, and expand its availability as a therapeutic option for diverse hepatic conditions.

Anaesthesia management for liver transplantation: A narrative review

Orthotopic liver transplantation is the definitive standard treatment for end-stage liver disease. Orthotopic liver transplantation anaesthesia management is a complex procedure that requires a multidisciplinary team approach. Understanding the complex pathophysiology of end-stage liver disease and its complications in the affected systems is essential for proper anaesthesia management in orthotopic liver transplantation. Orthotopic liver transplantation is a dynamic process, and preoperative optimisation is essential in these patients. Therefore, anaesthesiologists should focus on rapidly fluctuating physiology, haemodynamics, metabolic, and coagulation status in the anaesthesia management of these patients. Perioperative care and anaesthesia for orthotopic liver transplantation can be divided into preoperative evaluation, anaesthesia induction and management, dissection, anhepatic, neo-hepatic, and postoperative care, with essential anaesthetic considerations at each point. Considering the clinical situation, haemodynamic changes, misapplications, knowledge, attitude, and multimodal and multidisciplinary approach are vital in anaesthesia and the perioperative period. In our review, in line with the literature, we aimed to present the perioperative and anaesthesia management in orthotopic liver transplantation patients.

Hepatic Encephalopathy by Manganese Deposition: A Case Report and a Review of Literature

BACKGROUND

Hepatic encephalopathy is defined as a spectrum of neuropsychiatric disorders in patients with liver dysfunction, usually cirrhosis, after exclusion of brain disease. This study reports the role of manganese in brain alterations and therefore in clinical manifestations of hepatic encephalopathy.

CASE PRESENTATION

Male patient, 67 years old, suffering from alcoholic liver cirrhosis and two previous episodes of hepatic encephalopathy, developed drowsiness, asterixis, amnesia, disorientation in time and space, and psychomotor retardation. Brain MRI without contrast showed: initial signs of cerebral atrophy, a hyperintense signal of globi pallidi and bilateral substantia nigra. The hyperintense signal of globi pallidi is the result of manganese deposition in the brain.

CONCLUSION

The case report presented supports the data reported in the literature indicating that the increase in plasma manganese levels in subjects with liver dysfunction is correlated with the onset of extrapyramidal symptoms.

Redefining Success After Liver Transplantation: From Mortality Toward Function and Fulfillment

Liver transplantation (LT), the only cure for end-stage liver disease, is a lifesaving, costly, and limited resource. LT recipients (LTRs) are aging with an increasing burden of medical comorbidities. Patient and graft survival rates exceed 70% at 5 years; however, patient-centered health outcomes beyond survival have received relatively little attention. LTRs must have strong self-management skills to navigate health systems, adhere to clinical monitoring, and take complex, multidrug regimens. All of these tasks require formidable cognitive abilities for active learning and problem solving. Yet, LTRs are at higher risk for impaired cognition as a result of the high prevalence of pretransplant hepatic encephalopathy, multiple chronic conditions, alcohol use, physical frailty, sarcopenia, and older age. Cognitive impairment after transplant may persist and has been causally linked to poor self-management skills, worse physical function, and inferior health outcomes in other health care settings, yet its impact after LT is largely unknown. There is a need to study potentially modifiable, posttransplant targets including caregiver support, physical activity, sleep, and treatment adherence to inform future health system responses to promote the long-term health and well-being of LTRs. Prospective, longitudinal data collection that encompasses key sociodemographic, cognitive-behavioral, psychosocial, and medical factors is needed to improve risk prediction and better inform patient and caregiver expectations. Interventions with proactive monitoring, reducing medical complexity, and improved care coordination can be tailored to optimize posttransplant care. We propose a research agenda focused on understudied, potentially modifiable risk factors to improve the long-term health of LTRs. Our conceptual model accounts for cognitive function, caregiver and patient self-management skills, health behaviors, and patient-centered outcomes beyond mortality. We propose actionable health-system, patient, and caregiver-directed interventions to fill knowledge gaps and improve outcomes.

Role of circadian rhythm and autonomic nervous system in liver function: a hypothetical basis for improving the management of hepatic encephalopathy

Hepatic encephalopathy (HE) is a common, incapacitating complication of cirrhosis that affects many patients with cirrhosis. Although several therapies have proven effective in the treatment and prevention of this condition, several patients continue to suffer from covert disease or episodes of relapse. The circadian rhythm has been demonstrated to be pivotal for many body functions, including those of the liver. Here, we explore the impact of circadian rhythm-dependent signaling on the liver and discuss the evidence of its impact on liver pathology and metabolism. We describe the various pathways through which circadian influences are mediated. Finally, we introduce a novel method for improving patient response to drugs aimed at treating HE by utilizing the circadian rhythm. A digital system that introduces a customization-based technique for improving the response to therapies is presented as a hypothetical approach for improving the effectiveness of current medications used for the treatment of recurrent and persistent hepatic encephalopathy.

Polyethylene glycol versus lactulose in the treatment of hepatic encephalopathy: a systematic review and meta-analysis

Background

Hepatic encephalopathy (HE) is defined as brain dysfunction that occurs because of acute liver failure or liver cirrhosis and is associated with significant morbidity and mortality. Lactulose is the standard of care till this date; however, polyethylene glycol (PEG) has gained the attention of multiple investigators.

Methods

We screened five databases namely PubMed, Scopus, Web of Science, Cochrane Library and Embase from inception to 10 February 2021. Dichotomous and continuous data were analysed using the Mantel-Haenszel and inverse variance methods, respectively, which yielded a meta-analysis comparing PEG versus lactulose in the treatment of HE.

Results

Four trials with 229 patients were included. Compared with lactulose, the pooled effect size demonstrated a significantly lower average HE Scoring Algorithm (HESA) Score at 24 hours (Mean difference (MD)=−0.68, 95% CI (−1.05 to –0.31), p<0.001), a higher proportion of patients with reduction of HESA Score by ≥1 grade at 24 hours (risk ratio (RR)=1.40, 95% CI (1.17 to 1.67), p<0.001), a higher proportion of patients with a HESA Score of grade 0 at 24 hours (RR=4.33, 95% CI (2.27 to 8.28), p<0.0010) and a shorter time to resolution of HE group (MD=−1.45, 95% CI (−1.72 to –1.18), p<0.001) in favour of patients treated with PEG.

Conclusion

PEG leads to a higher drop in the HESA Score and thus leads to a faster resolution of HE compared with lactulose.

Nursing Management of Hepatic Encephalopathy

This article provides a background of hepatic encephalopathy, its relation to liver disease as well as its prevalence in the United States. A literature review provides an overview of HE discussing the pathophysiology, evidence-based diagnosis, and grading of the disease severity as well as treatment options and interventions. A large emphasis of the article is placed on nursing's role of identifying and managing hepatic encephalopathy. The authors hope to provide clinical nurses with the tools and information needed to provide evidence-based care to this patient population. Pharmacologic therapies, as well as nutrition for these patients, are other topics reviewed. Education for nurses on the management of hepatic encephalopathy is important, as well as education needed for patients and families to support them through the treatment and follow-up care needed to manage hepatic encephalopathy. The authors also hope to provide nurses with education tips to provide the patients and families they care for during their hospitalization with HE, as well as on discharge from the hospital to prevent reoccurrence of symptoms.

Hyponatremia and Its Correlation With Hepatic Encephalopathy and Severity of Liver Disease

Background and objective

Hepatic cirrhosis is one of the leading causes of morbidity and mortality worldwide. Patients with cirrhosis frequently develop complications such as ascites, variceal bleeding, and hepatic encephalopathy (HE). The clinical manifestations of HE range from the mildly altered level of sensorium to severely altered consciousness levels, difficulty in judgment, the day-night reversal of sleep, flapping tremor of hands, and irrelevant talking or speech. Patients with hyponatremia are at a higher risk of developing HE and electroencephalographic abnormalities. The severity of hyponatremia is directly related to the deterioration in terms of grades of HE. Our study sought to determine the frequency of hyponatremia in cirrhotic patients and its correlation with the frequency and severity of HE.

Methodology

This study was carried out at the inpatient department of medicine in a tertiary care hospital in Pakistan. A total of 260 patients of both genders with hepatic cirrhosis were approached. After taking relevant history and physical examination, the venous blood sample of each patient was drawn and sent to the institutional laboratory for estimation of serum electrolytes, liver function tests (LFTs), renal parameters (RPMs), prothrombin time (PT), activated partial thromboplastin time (aPTT), and international normalized ratio (INR). We classified the HE according to the West Haven classification system. Mild to moderate encephalopathy was classified under grades I-II, while severe encephalopathy was classified under grades III-IV. We documented the severity of liver disease according to the Child-Pugh score criteria. All data were analyzed by using SPSS Statistics version 25.0 (IBM, Armonk, NY). We reported the data as means along with the standard error.

Results

Overall, the serum sodium levels of the subjects ranged from 115 to 142 meq/L with a mean of 129.11 ±6.53 meq/L. In patients with hyponatremia, it ranged from 115 to 127 meq/L (mean 121.41 ±5.17 meq/L). Hyponatremia was present in 96 (36.9%) patients. Among these, 51 (53.12%) were male and 45 (46.8%) were female; 24 (9.2%) patients had mild hyponatremia, 56 (21.5%) had moderate, and 16 (6.2%) had severe hyponatremia. HE was present in 176 (67.7%) patients. HE grade I was present in 54 (20.8%), grade II in 62 (23.8%), grade III in 32 (12.3%), and grade IV in 28 (10.8%) patients. In 96 patients with hyponatremia, 84 were found to have HE (p-value: <0.001).

Conclusion

Based on our findings, cirrhotic patients with chronic hepatitis infections have a variable presence of low sodium levels. Sodium levels of <130 meq/L were associated with higher morbidity and mortality rate. Moreover, patients with lower levels of sodium had higher grades of HE.

Ammonia inhibits energy metabolism in astrocytes in a rapid and glutamate dehydrogenase 2-dependent manner

Astrocyte dysfunction is a primary factor in hepatic encephalopathy (HE) impairing neuronal activity under hyperammonemia. In particular, the early events causing ammonia-induced toxicity to astrocytes are not well understood. Using established cellular HE models, we show that mitochondria rapidly undergo fragmentation in a reversible manner upon hyperammonemia. Further, in our analyses, within a timescale of minutes, mitochondrial respiration and glycolysis were hampered, which occurred in a pH-independent manner. Using metabolomics, an accumulation of glucose and numerous amino acids, including branched chain amino acids, was observed. Metabolomic tracking of 15N-labeled ammonia showed rapid incorporation of 15N into glutamate and glutamate-derived amino acids. Downregulating human GLUD2 [encoding mitochondrial glutamate dehydrogenase 2 (GDH2)], inhibiting GDH2 activity by SIRT4 overexpression, and supplementing cells with glutamate or glutamine alleviated ammonia-induced inhibition of mitochondrial respiration. Metabolomic tracking of 13C-glutamine showed that hyperammonemia can inhibit anaplerosis of tricarboxylic acid (TCA) cycle intermediates. Contrary to its classical anaplerotic role, we show that, under hyperammonemia, GDH2 catalyzes the removal of ammonia by reductive amination of α-ketoglutarate, which efficiently and rapidly inhibits the TCA cycle. Overall, we propose a critical GDH2-dependent mechanism in HE models that helps to remove ammonia, but also impairs energy metabolism in mitochondria rapidly.

Non-Lactulose Medication Therapies for the Management of Hepatic Encephalopathy: A Literature Review

OBJECTIVE

The most appropriate medication regimen to mitigate the consequences hepatic encephalopathy remains inconclusive. This review seeks to serve as a reference for clinicians to help guide therapy decisions with regard to hepatic encephalopathy.

METHODS

A comprehensive literature review between August 2018 and April 2019 was accomplished with the assistance of a medical librarian. Sources of literature review include PubMed, MEDLINE, SCOPUS, ProQuest Central, CINAHL, and ProQuest Dissertations. The authors selected randomized clinical and double-blind cross-over trials evaluating probiotics, zinc, polyethylene glycol, rifaximin, and flumazenil. Sixteen clinical trials are discussed in this review. Pertinent safety, efficacy, and statistical and clinical outcomes are summarized by the authors.

CONCLUSIONS

The most appropriate regimen to mitigate the consequences of hepatic encephalopathy remains elusive; however, the agents discussed within this review offer alternative options for patients unresponsive to or intolerant of traditional lactulose therapy. This review seeks to serve as a repository for relevant clinical trials, and as a reference for clinicians to help guide therapy decisions.

Fibroblast Growth Factor-21 ameliorates hepatic encephalopathy by activating the STAT3-SOCS3 pathway to inhibit activated hepatic stellate cells

Neurological dysfunction, one of the consequences of acute liver failure (ALF), and also referred to as hepatic encephalopathy (HE), contributes to mortality posing challenges for clinical management. FGF21 has been implicated in the inhibition of cognitive decline and fibrogenesis. However, the effects of FGF21 on the clinical and molecular presentations of HE has not been elucidated. HE was induced by fulminant hepatic failure using thioacetamide (TAA) in male C57BL/6J mice while controls were injected with saline. For two consecutive weeks, mice were treated intraperitoneally with FGF21 (3 mg/kg) while controls were treated with saline. Cognitive, neurological, and activity function scores were recorded. Serum, liver, and brain samples were taken for analysis of CCL5 and GABA by ELISA, and RT qPCR was used to measure the expressions of fibrotic and pro-inflammatory markers. We report significant improvement in both cognitive and neurological scores by FGF21 treatment after impairment by TAA. GABA and CCL5, key factors in the progression of HE were also significantly reduced in the treatment group. Furthermore, the expression of fibrotic markers such as TGFβ and Col1 were also significantly downregulated after FGF21 treatment. TNFα and IL-6 were significantly reduced in the liver while in the brain, TNFα and IL-1 were downregulated. However, both in the liver and the brain, IL-10 was significantly upregulated. FGF21 inhibits CXCR4/CCL5 activation and upregulates the production of IL-10 in the damaged liver stimulating the production pro-inflammatory cytokines and apoptosis of hepatic stellate cells through the STAT3-SOCS3 pathway terminating the underlying fibrosis in HE.

Efficacy and Safety of Sodium Benzoate in The Management of Hyperammonemia in Decompensated Chronic Liver Disease of the Childhood-A Double-blind Randomized Controlled Trial

OBJECTIVE

The objective was to evaluate the efficacy and safety of sodium benzoate in the management of hyperammonemia and hepatic encephalopathy (HE) in decompensated chronic liver disease.

METHODS

It was a prospective, interventional, double-blinded randomized controlled trial conducted from August 2017 to December 2018. Children with decompensated chronic liver disease and hyperammonemia were included in the study. Those with ammonia >400 μg/dL, already receiving sodium benzoate or with grade III ascites were excluded. Group A received sodium benzoate (400 mg/kg loading dose followed by 200 mg · kg · daymaintenance for 5 days) along with the standard medical therapy. Group B received standard medical therapy with placebo.

RESULTS

A total of 108 episodes of hyperammonemia occurred in 86 patients of whom 16 were excluded. The final analysis included 46 episodes in each group. The median decrease in ammonia from baseline to day 5 was 52 μg/dL in group A versus 42 μg/dL in group B (P = 0.321). There was a significant decrease in ammonia on days 1 and 2 in group A as compared to group B, but not on subsequent days. There was no significant difference in the resolution of HE (57.1% vs 50%; P = 1), but there was higher, albeit insignificant increase in ascites in group A (15.9% vs 4.5%).

CONCLUSIONS

Addition of sodium benzoate significantly reduced the ammonia levels on the first 2 days of therapy but the effect was not sustained till day 5. The effect of sodium benzoate would probably be more sustained, if higher dosage (400 mg · kg · day) could be used under monitoring of benzoate levels. There was no effect on resolution of HE. Sodium benzoate caused an increasing trend of adverse events with no effect on short-term survival.

Iron and manganese-related CNS toxicity: mechanisms, diagnosis and treatment

INTRODUCTION

Iron (Fe) and manganese (Mn) are essential nutrients for humans. They act as cofactors for a variety of enzymes. In the central nervous system (CNS), these two metals are involved in diverse neurological activities. Dyshomeostasis may interfere with the critical enzymatic activities, hence altering the neurophysiological status and resulting in neurological diseases. Areas covered: In this review, the authors cover the molecular mechanisms of Fe/Mn-induced toxicity and neurological diseases, as well as the diagnosis and potential treatment. Given that both Fe and Mn are abundant in the earth crust, nutritional deficiency is rare. In this review the authors focus on the neurological disorders associated with Mn and Fe overload. Expert commentary: Oxidative stress and mitochondrial dysfunction are the primary molecular mechanism that mediates Fe/Mn-induced neurotoxicity. Although increased Fe or Mn concentrations have been found in brain of patients, it remains controversial whether the elevated metal amounts are the primary cause or secondary consequence of neurological diseases. Currently, treatments are far from satisfactory, although chelation therapy can significantly decrease brain Fe and Mn levels. Studies to determine the primary cause and establish the molecular mechanism of toxicity may help to adapt more comprehensive and satisfactory treatments in the future.

Changes in Cerebral Hemodynamics in Patients With Cirrhosis After Liver Transplantation

Improvement in cognitive function after orthotopic liver transplantation (LT) has been demonstrated in the acute setting immediately after LT and in acute liver failure. However, the longterm changes in cerebral hemodynamics after LT remain unexplored. Therefore, we aimed to evaluate the longterm changes in cerebral hemodynamics of patients with cirrhosis after LT. In this prospective cohort study, we performed transcranial Doppler ultrasonography (TCD) measuring the pulsatility index (PI), resistance index (RI), and breath-holding index (BHI) to evaluate cerebrovascular structural integrity and reactivity, respectively, in both middle cerebral arteries before and after LT. Neuropsychometric tests and West-Haven criteria were used for hepatic encephalopathy (HE) characterization. Interleukin 6 and tumor necrosis factor α plasma levels were measured. Descriptive statistics and Wilcoxon's test were used. There were 27 patients who were included. Median follow-up after LT was 6 months, mean age before LT was 46.3 ± 10.3 years, the main etiology was hepatitis C virus (59%), and most of the patients were Child-Pugh B (15/27). Model for End-Stage Liver Disease (MELD) score was 16 ± 7.5, MELD-Na was 19.3 ± 7.1, Psychometric Hepatic Encephalopathy Score was -3.48 ± 3.66, and critical flicker fusion (CFF) was 40.28 ± 5.70 Hz. Before LT, 17/27 patients had HE and 11/27 ascites. A decrease of 20.8% and 13.5% in PI and RI was observed after LT (P < 0.001, both), together with an increase in BHI (32.4%, P = 0.122). These changes in cerebral hemodynamics paralleled those in systemic inflammation. Clinical improvement in cognition was observed in all patients with overt HE after LT. In conclusion, these results show a significant improvement in cerebral hemodynamics after LT, obtained through TCD, indicating less arterial cerebral vasoconstriction together with a decrease in systemic inflammation. Changes in cerebral vasoconstriction can be the basis for the improvement in cognitive function after LT in the long term.

Multimodal MR imaging in hepatic encephalopathy: state of the art

Hepatic encephalopathy (HE) is a neurological or neuropsychological complication due to liver failure or portosystemic shunting. The clinical manifestation is highly variable, which can exhibit mild cognitive or motor impairment initially, or gradually progress to a coma, even death, without treatment. Neuroimaging plays a critical role in uncovering the neural mechanism of HE. In particular, multimodality MR imaging is able to assess both structural and functional derangements of the brain with HE in focal or neural network perspectives. In recent years, there has been rapid development in novel MR technologies and applications to investigate the pathophysiological mechanism of HE. Therefore, it is necessary to update the latest MR findings regarding HE by use of multimodality MRI to refine and deepen our understanding of the neural traits in HE. Herein, this review highlights the latest MR imaging findings in HE to refresh our understanding of MRI application in HE.

Biological Activities of Lactose-Derived Prebiotics and Symbiotic with Probiotics on Gastrointestinal System

Lactose-derived prebiotics provide wide ranges of gastrointestinal comforts. In this review article, the probable biochemical mechanisms through which lactose-derived prebiotics offer positive gastrointestinal health are reported along with the up-to-date results of clinical investigations; this might be the first review article of its kind, to the best of our knowledge. Lactose-derived prebiotics have unique biological and functional values, and they are confirmed as ‘safe’ by the Food and Drug Administration federal agency. Medical practitioners frequently recommend them as therapeutics as a pure form or combined with dairy-based products (yoghurt, milk and infant formulas) or fruit juices. The biological activities of lactose-derived prebiotics are expressed in the presence of gut microflora, mainly probiotics (Lactobacillus spp. in the small intestine and Bifidobacterium spp. in the large intestine). Clinical investigations reveal that galacto-oligosaccharide reduces the risks of several types of diarrhea (traveler’s diarrhea, osmotic diarrhea and Clostridium difficile associated relapsing diarrhea). Lactulose and lactosucrose prevent inflammatory bowel diseases (Crohn’s disease and ulcerative colitis). Lactulose and lactitol reduce the risk of hepatic encephalopathy. Furthermore, lactulose, galacto-oligosaccharide and lactitol prevent constipation in individuals of all ages. It is expected that the present review article will receive great attention from medical practitioners and food technologists.

The Aging of Iron Man

Brain iron is tightly regulated by a multitude of proteins to ensure homeostasis. Iron dyshomeostasis has become a molecular signature associated with aging which is accompanied by progressive decline in cognitive processes. A common theme in neurodegenerative diseases where age is the major risk factor, iron dyshomeostasis coincides with neuroinflammation, abnormal protein aggregation, neurodegeneration, and neurobehavioral deficits. There is a great need to determine the mechanisms governing perturbations in iron metabolism, in particular to distinguish between physiological and pathological aging to generate fruitful therapeutic targets for neurodegenerative diseases. The aim of the present review is to focus on the age-related alterations in brain iron metabolism from a cellular and molecular biology perspective, alongside genetics, and neuroimaging aspects in man and rodent models, with respect to normal aging and neurodegeneration. In particular, the relationship between iron dyshomeostasis and neuroinflammation will be evaluated, as well as the effects of systemic iron overload on the brain. Based on the evidence discussed here, we suggest a synergistic use of iron-chelators and anti-inflammatories as putative anti-brain aging therapies to counteract pathological aging in neurodegenerative diseases.

Regression of Asymmetric Upper Extremity Tremor After Liver Transplantation in a Patient With Hepatic Encephalopathy: Case Report

SUMMARY – Hepatic encephalopathy (HE) is a brain dysfunction caused by liver failure. Clinically, it can manifests as a wide spectrum of neurological or psychiatric abnormalities. This report presents a case of a 43-year-old male with HE and asymmetric kinetic, postural and resting tremor of upper extremities. Magnetic resonance imaging (MRI) of the brain showed signal abnormalities in numerous areas. The patient underwent liver transplantation and six months after normalization of liver function, tremor as well as brain MRI abnormalities almost completely regressed. This case report presents the asymmetric and reversible kinetic, postural and resting tremor of upper extremities as part of the spectrum of neurological abnormalities in HE.

PET and MR imaging of neuroinflammation in hepatic encephalopathy

Neurological or psychiatric abnormalities associated with hepatic encephalopathy (HE) range from subclinical findings to coma. HE is commonly accompanied with the accumulation of toxic substances in bloodstream. The toxicity effect of hyperammonemia on astrocyte, such as the alteration in neurotransmission, oxidative stress, astrocyte swelling, is considered as an important factor in the pathogenesis of HE. Besides, neuroinflammation has captured more attention in the process of HE, but the mechanism of neuroinflammation leading to HE remains unclear. Molecular imaging techniques such as positron emission tomography (PET) and magnetic resonance imaging (MRI) targeting activated microglia and/ or other mediators appear to be promising noninvasive approaches to assess HE. This review focuses on novel imaging and therapy strategies of neuroinflammation in HE.