Prognostic Role of Ammonia in Patients With Cirrhosis

The Story of Ammonia in Liver Disease: An Unraveling Continuum

Hyperammonemia and liver disease are closely linked. Most of the ammonia in our body is produced by transamination and deamination activities involving amino acid, purine, pyrimidines, and biogenic amines, and from the intestine by bacterial splitting of urea. The only way of excretion from the body is by hepatic conversion of ammonia to urea. Hyperammonemia is associated with widespread toxicities such as cerebral edema, hepatic encephalopathy, immune dysfunction, promoting fibrosis, and carcinogenesis. Over the past two decades, it has been increasingly utilized for prognostication of cirrhosis, acute liver failure as well as acute on chronic liver failure. The laboratory assessment of hyperammonemia has certain limitations, despite which its value in the assessment of various forms of liver disease cannot be negated. It may soon become an important tool to make therapeutic decisions about the use of prophylactic and definitive treatment in various forms of liver disease.

Hybrid MoSe2/P3HT Transistor for Real-Time Ammonia Sensing in Biofluids

Organic and inorganic hybrid field-effect transistors (FETs), utilizing layered molybdenum diselenide (MoSe2) and an organic semiconductor poly(3-hexylthiophene) (P3HT), are presented for biosensing applications. A new hybrid device structure that combines organic (P3HT) and inorganic (MoSe2) components is showcased for accurate and selective bioanalyte detection in human bodily fluids to overcome 2D-transition metal dichalcogenides (TMDs) nonspecific interactions. This hybrid structure utilizes organic and inorganic semiconductors' high surface-to-volume ratio, carrier transport, and conductivity for biosensing. Ammonia concentrations in saliva and plasma are closely linked to physiological and pathological conditions of the human body. A highly sensitive hybrid FET biosensor detects total ammonia (NH4+ and NH3) from 0.5 μM to 1 mM concentrations, with a detection limit of 0.65 μM in human bodily fluids. The sensor's ammonia specificity in artificial saliva against interfering species is showcased. Furthermore, the fabricated hybrid FET device exhibits a stable and repeatable response to ammonia in both saliva and plasma, achieving a remarkable response level of 2300 at a 1 mM concentration of ammonia, surpassing existing literature by 10-fold. This hybrid FET biosensing platform holds significant promise for developing a precise tool for the real-time monitoring of ammonia concentrations in human biological fluids, offering potential applications in point-of-care diagnostics.

Ammonia Detection by Electronic Noses for a Safer Work Environment

Providing employees with proper work conditions should be one of the main concerns of any employer. Even so, in many cases, work shifts chronically expose the workers to a wide range of potentially harmful compounds, such as ammonia. Ammonia has been present in the composition of products commonly used in a wide range of industries, namely production in lines, and also laboratories, schools, hospitals, and others. Chronic exposure to ammonia can yield several diseases, such as irritation and pruritus, as well as inflammation of ocular, cutaneous, and respiratory tissues. In more extreme cases, exposure to ammonia is also related to dyspnea, progressive cyanosis, and pulmonary edema. As such, the use of ammonia needs to be properly regulated and monitored to ensure safer work environments. The Occupational Safety and Health Administration and the European Agency for Safety and Health at Work have already commissioned regulations on the acceptable limits of exposure to ammonia. Nevertheless, the monitoring of ammonia gas is still not normalized because appropriate sensors can be difficult to find as commercially available products. To help promote promising methods of developing ammonia sensors, this work will compile and compare the results published so far.

Hepatic Encephalopathy-A Guide to Laboratory Testing

Hepatic encephalopathy (HE) remains both a clinical diagnosis and one of exclusion. Laboratory testing is largely focused on identifying precipitating factors. Ammonia levels in the blood can be helpful for the diagnosis of HE but are not required for confirmation. More recent literature is lending support to the prognostic capabilities of ammonia in cirrhosis, both in predicting future HE events and in determining outcomes in hospitalized patients. Accurate ammonia testing requires strict protocols to avoid common pitfalls in the measurement of this labile analyte. Future studies investigating the utility of other laboratory testing to diagnose, stage, or predict HE are encouraged.

Risk of Cerebral Aneurysm Rupture After Liver Transplantation: Development and Validation of a Hemorrhagic Stroke Scoring Model

BACKGROUND

Liver transplantation (LT) patients appear to be more prone to neurological events compared to individuals undergoing other types of solid-organ transplantation. The aims of the present study were to analyze the prevalence of unruptured intracranial aneurysms (UIAs) in patients undergoing liver transplantation (LT) and to examine the perioperative occurrence of subarachnoid hemorrhage (SAH). Also, it intended to systematically identify the risk factors of SAH and hemorrhagic stroke (HS) within a year after LT and to develop a scoring system which involves distinct clinical features of LT patients.

METHODS

Patients who underwent LT from January 2012 to March 2022 were analyzed. All included patients underwent neurovascular imaging within 6 months before LT. We conducted an analysis of prevalence and radiological features of UIA and SAH. The clinical factors that may have an impact on HS within one year of LT were also reviewed.

RESULTS

Total of 3,487 patients were enrolled in our study after applying inclusion and exclusion criteria. The prevalence of UIA was 5.4%. The incidence of SAH and HS within one year following LT was 0.5% and 1.6%, respectively. We developed a scoring system based on multivariable analysis to predict the HS within 1-year after LT. The variables were a poor admission mental status, the diagnosis of UIA, serum ammonia levels, and Model for End-stage Liver Disease (MELD) scores. Our model showed good discrimination among the development (C index, 0.727; 95% confidence interval [CI], 0.635-0.820) and validation (C index, 0.719; 95% CI, 0.598-0.801) cohorts.

CONCLUSION

The incidence of UIA and SAH was very low in LT patients. A poor admission mental status, diagnosis of UIA, serum ammonia levels, and MELD scores were significantly associated with the risk of HS within one year after LT. Our scoring system showed a good discrimination to predict the HS in LT patients.

Ammonia is associated with liver-related complications and predicts mortality in acute-on-chronic liver failure patients

The relationship between ammonia and liver-related complications (LRCs) in acute-on-chronic liver failure (ACLF) patients is not clearly established. This study aimed to evaluate the association between ammonia levels and LRCs in patients with ACLF. The study also evaluated the ability of ammonia in predicting mortality and progression of LRCs. The study prospectively recruited ACLF patients based on the APASL definition from the ACLF Research Consortium (AARC) from 2009 to 2019. LRCs were a composite endpoint of bacterial infection, overt hepatic encephalopathy (HE), and ascites. A total of 3871 cases were screened. Of these, 701 ACLF patients were enrolled. Patients with LRCs had significantly higher ammonia levels than those without. Ammonia was significantly higher in patients with overt HE and ascites, but not in those with bacterial infection. Multivariate analysis found that ammonia was associated with LRCs. Additionally, baseline arterial ammonia was an independent predictor of 30-day mortality, but it was not associated with the development of new LRCs within 30 days. In summary, baseline arterial ammonia levels are associated with 30-day mortality and LRCs, mainly overt HE and ascites in ACLF patients.

Hepatic encephalopathy: From novel pathogenesis mechanism to emerging treatments

Hepatic encephalopathy (HE) is one of the major complications of liver disease and significantly affects the quality of life (QOL) of patients. HE is common and frequently relapses in cirrhotic patients. The management of HE is supportive, and precipitating conditions should be eliminated. Most drugs used to treat HE are conventional and include nonabsorbable disaccharides such as lactulose, and antibiotics such as rifaximin. However, their therapeutic efficacy is still suboptimal, and novel therapeutic agents are urgently needed. In addition, the optimal management and diagnosis of minimal HE/covert HE are under debate. In this review, we focus on novel pathogenetic mechanisms such as central nervous system clearance, and emerging therapeutic targets of HE, such as fecal material transplantation. We also discuss different classifications and etiologies of HE.

The challenges and potential in developing microRNA associated with regeneration as biomarkers to improve prognostication for liver failure syndromes and hepatocellular carcinoma

INTRODUCTION

Determining the need for liver transplantation remains critical in the management of hepatocellular carcinoma (HCC) and liver failure syndromes (including acute liver failure and decompensated cirrhosis states). Conventional prognostic models utilize biomarkers of liver and non-liver failure and have limitations in their application. Novel biomarkers which predict regeneration may fulfil this niche. microRNA are implicated in health and disease and are present in abundance in the circulation. Despite this, they have not translated into mainstream clinical biomarkers.

AREAS COVERED

We will discuss current challenges in the prognostication of patients with liver failure syndromes as well as for patients with HCC. We will discuss biomarkers implicated with liver regeneration. We then provide an overview of the challenges in developing microRNA into clinically tractable biomarkers. Finally, we will provide a scoping review of microRNA which may have potential as prognostic biomarkers in liver failure syndromes and HCC.

EXPERT OPINION

Novel biomarkers are needed to improve prognostic models in liver failure syndromes and HCC. Biomarkers associated with liver regeneration are currently lacking and may fulfil this niche. microRNA have the potential to be developed into clinically tractable biomarkers but a consensus on standardizing methodology and reporting is required prior to large-scale studies.

The Management of Hepatic Encephalopathy from Ward to Domiciliary Care: Current Evidence and Gray Areas

Hepatic encephalopathy (HE) is a common complication of advanced liver disease and acute liver failure. It is a condition that features several neuropsychiatric symptoms that affect mortality, morbidity and the quality of patients' and caregivers' lives. An HE diagnosis is generally an exclusion diagnosis. Once the patient is admitted to the hospital, clinical examination, blood tests and eventually neuroimaging should be performed with the aim of ruling out other causes of acute brain dysfunction. Moreover, HE is recognized using various precipitants that can potentially promote its onset, alone or in combination, and must be identified. Once the diagnostic process is complete, a correct treatment should be started. The anti-HE treatment is based on a combination of the correction of precipitants; non-absorbable antibiotics, such as rifaximin; and non-absorbable disaccharides. Once the patient is discharged from the hospital, specific anti-HE therapy should be maintained in order to prevent other HE episodes.

Serum ammonia variation predicts mortality in patients with hepatitis B virus-related acute-on-chronic liver failure

Background

Hyperammonemia is critical to the development of hepatic encephalopathy (HE) and is associated with mortality in end-stage liver disease. This study investigated the clinical value of ammonia variation in hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) patients.

Methods

A total of 276 patients with HBV-ACLF were retrospectively recruited. Patients' ammonia levels were serially documented. Baseline ammonia, Peak ammonia (highest level), and Trough ammonia (lowest level) were particularly corrected to the upper limit of normal (AMM-ULN). The primary endpoint was 28-day mortality.

Results

The 28-day, 3-month, and 12-month mortality rates were 19.2, 25.7, and 28.2%, respectively. A total of 51 (18.4%) patients had overt HE (grade 2/3/4). Peak AMM-ULN was significantly higher in patients with overt HE and non-survivors compared with their counterparts (P < 0.001). Following adjustment for significant confounders, high Peak AMM-ULN was an independent predictor of overt HE (hazard ratio, 1.031, P < 0.001) and 28-day mortality (hazard ratio, 1.026, P < 0.001). The cut-off of Peak AMM-ULN was 1.8, determined by using the X-tile. Patients with Peak AMM-ULN appearing on days 1-3 after admission had a higher proportion of overt HE and mortality compared to other groups. Patients with decreased ammonia levels within 7 days had better clinical outcomes than those with increased ammonia.

Conclusion

Serum Peak ammonia was independently associated with overt HE and mortality in HBV-ACLF patients. Serial serum ammonia may have prognostic value.

Predictors of 30-day mortality in patients diagnosed with hepatic encephalopathy on admission to the emergency department

BACKGROUND

The aim of this study is to compare the laboratory findings and disease severity scores of patients diagnosed with hepatic encephalopathy (HE) in the emergency department (ED) to predict 30-day mortality.

METHOD

The patients over 18 years old and diagnosed HE in the ED of a tertiary hospital were included in the study. Demographic and clinical characteristics, laboratory parameters, predisposing causes and outcomes of the patients included in the study were recorded in the data form. Severity of liver disease was assessed by Child Pugh Score (CPS), End-stage liver disease model (MELD), MELD-Na and MELD-Lactate scores.

RESULTS

Two hundred fifty-four patients diagnosed with HE were included in the study. 59.1% of the patients were male. The mean age of the patients was 65.2 ± 12.6 years. The mortality rate of the patients was 47.2%. When the receiver operating characteristic (ROC) analysis, which determines the predictive properties of laboratory parameters and disease severity scores, was examined, the area under curve value of the MELD-Lactate score (0.858 95% CI 0.812-0.904, P  < 0.001) was the highest. Binary logistic regression analysis for the estimation of patients' 30-day mortality showed that CPS and MELD-Lactate scores and blood ammonia and B-type natriuretic peptide levels were independent predictors of mortality.

CONCLUSION

According to the study data, MELD-Lactate and BNP levels in patients diagnosed with HE in the ED may help the clinician in the prediction of 30-day mortality in the early period.

Circulating neutrophil anti-pathogen dysfunction in cirrhosis

Neutrophils are the largest population of leucocytes and are among the first cells of the innate immune system to fight against intruding pathogens. In patients with cirrhosis, neutrophils exhibit altered functionality, including changes in phagocytic ability, bacterial killing, chemotaxis, degranulation, reactive oxygen species production and NET (neutrophil extracellular trap) formation. This results in their inability to mount an adequate antibacterial response and protect the individual from infection. Prognosis and survival in patients with cirrhosis are greatly influenced by the development of infectious complications. Multidrug-resistant bacterial infections in patients with cirrhosis are currently a growing problem worldwide; therefore, alternative methods for the prevention and treatment of bacterial infections in cirrhosis are urgently needed. The prevention and treatment of neutrophil dysfunction could be a potential way to protect patients from bacterial infections. However, the reasons for changes in neutrophil function in cirrhosis are still not completely understood, which limits the development of efficient therapeutic strategies. Both cellular and serum factors have been proposed to contribute to the functional impairment of neutrophils. Herein, we review the current knowledge on features and proposed causes of neutrophil dysfunction in cirrhosis, with a focus on current knowledge gaps and limitations, as well as opportunities for future investigations in this field.

Serum ammonia does not guide management and is overutilised in patients with cirrhosis in hospital settings

BACKGROUND

Hepatic encephalopathy is a confusional state associated with cirrhosis. Serum ammonia levels are neither sensitive nor specific for the diagnosis.

AIMS

We audited the ordering location and hospital unit whilst assessing the impact on management at a major Australian tertiary centre.

METHODS

We conducted a single-centre retrospective chart review of the ordering of serum ammonia levels between 1 March 2019 and 29 February 2020 at The Royal Melbourne Hospital, a tertiary-referral centre in Melbourne, Victoria. Demographic, medication and pathology results, including serum ammonia measurements, were collected. The main outcomes assessed were ordering location, sensitivity, specificity and impact on management.

RESULTS

A total of 1007 serum ammonia tests were ordered in 425 patients. Nearly all ammonia ordering was by non-gastroenterologists, 24.2% by the intensive care unit, 23.1% by general medicine and 19.5% by the emergency department (ED). Only 21.6% of patients had a history of cirrhosis, with hepatic encephalopathy diagnosed in 13.6%. On subgroup analysis, 217 ammonia tests were performed in 92 patients with cirrhosis. Cirrhotic patients were older (64 vs 59 years, P = 0.012) and had higher median ammonia levels (64.46 vs 59 μmol/L, P < 0.001) compared with non-cirrhotic patients. In cirrhotic patients, the sensitivity and specificity for serum ammonia and diagnosis of hepatic encephalopathy were 75% and 52.3% respectively.

CONCLUSION

We affirm the poor utility of serum ammonia levels for guiding management of hepatic encephalopathy within the Australian context. ED and general medical units account for the majority of test ordering within the hospital. Understanding where ordering occurs provides a target for targeted education.

Novel Therapeutic Approaches in Treatment of Acute-on-Chronic Liver Failure

Acute-on-chronic liver failure (ACLF), a clinical syndrome that can develop at any stage in the progression of cirrhotic liver disease, is characterized by an acute decompensation in liver function with associated multiorgan failure and high short-term mortality. Current evidence points to ACLF being reversible, particularly in those at the lower end of the severity spectrum. However, there are no specific treatments for ACLF, and overall outcomes remain poor. Expedited liver transplantation as a treatment option is limited by organ shortage and a lack of priority allocation for this indication. Other options are therefore urgently needed, and our improved understanding of the condition has led to significant efforts to develop novel therapies. In conclusion, this review aims to summarize the current understanding of the pathophysiological processes involved in the onset, progression, and recovery of ACLF and discuss novel therapies under development.

From Microcosm to Macrocosm: The -Omics, Multiomics, and Sportomics Approaches in Exercise and Sports

This article explores the progressive integration of -omics methods, including genomics, metabolomics, and proteomics, into sports research, highlighting the development of the concept of "sportomics." We discuss how sportomics can be used to comprehend the multilevel metabolism during exercise in real-life conditions faced by athletes, enabling potential personalized interventions to improve performance and recovery and reduce injuries, all with a minimally invasive approach and reduced time. Sportomics may also support highly personalized investigations, including the implementation of n-of-1 clinical trials and the curation of extensive datasets through long-term follow-up of athletes, enabling tailored interventions for athletes based on their unique physiological responses to different conditions. Beyond its immediate sport-related applications, we delve into the potential of utilizing the sportomics approach to translate Big Data regarding top-level athletes into studying different human diseases, especially with nontargeted analysis. Furthermore, we present how the amalgamation of bioinformatics, artificial intelligence, and integrative computational analysis aids in investigating biochemical pathways, and facilitates the search for various biomarkers. We also highlight how sportomics can offer relevant information about doping control analysis. Overall, sportomics offers a comprehensive approach providing novel insights into human metabolism during metabolic stress, leveraging cutting-edge systems science techniques and technologies.

Letter: Exploring the clinical utility of ammonia in critically ill patients with cirrhosis: More to do?

This article is linked to Cardoso et al papers. To view these articles, visit https://doi.org/10.1111/apt.17650 and https://doi.org/10.1111/apt.17725

Intravenous BCAA Infusion Does Not Lead to a Sustained Recovery From Overt HE in ACLF - An Open Label Randomized Clinical Trial

Background

Hepatic encephalopathy (HE) in acute-on-chronic liver failure (ACLF) is associated with significant morbidity and mortality. We conducted a prospective, randomized controlled clinical trial to study the efficacy of intravenous branched chain amino acids (IV-BCAA) with lactulose versus lactulose alone for improvement in HE at 24 h, day 3, and day 7. The primary outcome was an improvement in encephalopathy by ≥ 1 grade at 72 h.

Patients and methods

European association for study of liver (EASL) defined ACLF patients with overt HE were assessed and randomized into the experimental arm (IV-BCAA - 500 mL/day for 3 days + Lactulose; n = 39) and the comparator arm (Lactulose alone; n = 37). Six patients developed COVID-19 after randomization and were excluded (4-experimental arm and 2-comparator arm).

Results

Of 222 screened patients, 70 (35 in each arm) were included in the analysis. Baseline characteristics, including HE grade (2.9 ± 0.7 vs 2.8 ± 0.7; P = 0.86) and (chronic liver failure) CLIF-C ACLF score (54.2 ± 5.6 vs 54.8 ± 5.7; P = 0.65), were similar. Overall survival was 40% at 28 days (48.5% vs 31.4%; P = 0.14). Improvement in hepatic encephalopathy scoring algorithm (HESA) by ≥ 1 grade at 24 h occurred in 14 patients (40%) in the BCAA arm and 6 patients (17.1%) in the control group (P = 0.03) which translated to a shorter intensive care unit (ICU) stay. The median change in HESA at 24 h was greater in the BCAA arm than the control arm (P = 0.006), which was not sustained at days 3 or 7. Ammonia levels did not correlate with the grade of HE (Spearman's correlation coefficient (ρ) = - 0.0843; P = 0.29).

Conclusion

Intravenous BCAA does not lead to a sustained improvement in HE grade in ACLF.

Trial registration no

NCT04238416 (clinicaltrials.gov).

Hepatic encephalophaty: management and diagnostic therapeutic assistance path of Ligurian Local Health Company 3 (ASL3)

Hepatic encephalophaty (HE) is a neuropsychiatric syndrome with a prevalence in the cirrhotic population ranging from 20 to 80%. HE is a cause of inappropriate hospitalization, caregiver burdening and increased social costs. There is need to create dedicated care pathways to better manage patients and support family caregivers. The data used for the preparation of this diagnostic therapeutic assistance path (DTAP) are based on a detailed analysis of the scientific literature published before June 30, 2022 (PubMed, Web of Science, Scopus, Google Scholar). Furthermore, in the process of developing this work, we consulted in particular the guidelines/ position papers of International Society for Hepatic Encephalopathy and Nitrogen Metabolism (ISHEN), Italian Association for the Study of the Liver (AISF), European Association for the Study of the Liver (EASL), American Association for the Study of Liver Diseases (AASLD), Italian Society on Alcohol (Società Italiana di Alcologia [SIA]) and other relevant papers. DTAP was created based on the most recent recommendations of the international scientific literature. The present DTAP highlight the need for a multidisciplinary activity integrated with territorial medicine in close connection with caregivers. This guarantees improved therapeutic adherence, hospital readmission reduction, improved quality of life for patients and caregivers and a significant reduction in costs.

Early serum ammonia variation in critically ill patients with cirrhosis: A multicentre cohort study

BACKGROUND

Serum ammonia variation in critically ill patients with cirrhosis has been poorly studied.

AIM

To describe and assess the impact of serum ammonia variation in these patients' outcomes.

METHODS

We studied patients ≥18 years old admitted to the intensive care units (ICUs) at University of Alberta Hospital (Edmonton, Canada) and Curry Cabral Hospital (Lisbon, Portugal; derivation cohort, n = 492) and Northwestern University Hospital (Chicago, USA; validation cohort, n = 600) between January 2010 and December 2021. Primary exposure was ICU days 1-3 serum ammonia. Primary endpoint was all-cause hospital mortality.

RESULTS

In the derivation cohort, 330 (67.1%) patients were male and median (IQR) age was 57 (50-63) years. On ICU day 1, median ammonia was higher in patients with grade 3/4 hepatic encephalopathy (HE) than those with grade 2 HE or grade 0/1 HE (112 vs. 88 vs. 77 μmoL/L, respectively; p < 0.001). Furthermore, medium ammonia was higher in hospital non-survivors than survivors (99 vs. 86 μmol/L; p < 0.030). Following adjustment for significant confounders (age, HE, vasopressor use and renal replacement therapy delivery), higher ICU day 2 ammonia was independently associated with higher hospital mortality (adjusted OR per each 10 μmoL/L increment [95% CI] = 1.11 [1.01-1.21]; p = 0.024). In the validation cohort, this model with serial ammonia (ICU days 1 and 3) predicted hospital mortality with reasonably good discrimination (c-statistic = 0.73) and calibration (R2  = 0.19 and Brier score = 0.17).

CONCLUSIONS

Among patients with cirrhosis in the ICU, early serum ammonia variation was independently associated with hospital mortality. In this context, serial serum ammonia may have prognostic value.

Hepatic Encephalopathy in Cirrhotic Patients With Bacterial Infections: Frequency, Clinical Characteristics, and Prognostic Relevance

Background/Objectives

Bacterial infections (BIs) are well-recognized precipitants of hepatic encephalopathy (HE). Nevertheless, there is a paucity of data in patients with HE associated with BI. Our aim was to describe clinical characteristics, recurrence, and prognosis of HE in patients with BI.

Methods

A prospective study with inclusion of hospitalized cirrhotic patients with BI, followed until discharge, death, or liver transplantation.

Results

172 patients (age 57 ± 13, model of end-stage liver disease [MELD]-sodium 22 ± 8) were included. Infections were more commonly due to spontaneous bacterial peritonitis and cellulitis (22% and 23%), non-nosocomial (70%), and associated with systemic inflammatory response syndrome and septic shock in 40% and 9%, respectively. HE was diagnosed in 66 patients (grade ≥2 in 58%). In multivariate analysis, MELD-sodium, albumin, and prior HE were associated with HE at diagnosis of BI. Recurrence of HE was diagnosed in 30 patients (median 13 [interquartile range 5-22] days), more commonly manifested as overt HE (90% vs. 60% at first episode, P = 0.012) and more frequently in patients with hyponatremia (54% vs. 27% for patients without, P < 0.001). In-hospital mortality was 34% and was more common for patients with HE (51% vs. 22%, P < 0.001), irrespective of grade, and for those with recurrence (63% vs. 42%, P < 0.001). In multivariate analysis, HE at diagnosis of infection and MELD-sodium were predictors of mortality.

Conclusions

HE is frequent in cirrhotic patients with BI and is associated with severity of liver disease, but not with infection. These patients are at increased risk of short-term HE recurrence, especially those with hyponatremia. The presence and recurrence of HE, independent of severity, are associated with in-hospital mortality.

From Listing to Recovery: A Review of Nutritional Status Assessment and Management in Liver Transplant Patients

Liver transplantation (LT) is a complex surgical procedure requiring thorough pre- and post-operative planning and care. The nutritional status of the patient before, during, and after LT is crucial to surgical success and long-term prognosis. This review aims to assess nutritional status assessment and management before, during, and after LT, with a focus on patients who have undergone bariatric surgery. We performed a comprehensive topic search on MEDLINE, Ovid, In-Process, Cochrane Library, EMBASE, and PubMed up to March 2023. It identifies key factors influencing the nutritional status of liver transplant patients, such as pre-existing malnutrition, the type and severity of liver disease, comorbidities, and immunosuppressive medications. The review highlights the importance of pre-operative nutritional assessment and intervention, close nutritional status monitoring, individualised nutrition care plans, and ongoing nutritional support and monitoring after LT. The review concludes by examining the effect of bariatric surgery on the nutritional status of liver transplant recipients. The review offers valuable insights into the challenges and opportunities for optimising nutritional status before, during, and after LT.

Diagnosis and management of hepatic encephalopathy: The French recommendations

Hepatic encephalopathy (HE) is a frequent and severe complication of liver disease with poor patient outcomes. However, it is a poorly understood complication, with no consensus for diagnosis. Therefore, HE is often underdiagnosed. Differential diagnosis may be cumbersome because of non-specific symptoms, such as confusion, cognitive disorders, the aetiological factors of cirrhosis and comorbidities, which are often observed in cirrhotic patients. Therefore, an overt or covert form of HE should be systematically investigated. Advice is provided to drive patient work-up. Effective treatments are available to prevent or treat HE bouts, but the issue of single or combination therapy has not been resolved. Transjugular intrahepatic portosystemic shunt (TIPS) placement largely improved the prognosis of cirrhotic patients, but HE occurrence of HE is often a fear, even when post-TIPS HE can be avoided by a careful selection of patients and preventive treatment. HE is an indication of liver transplantation. However, its reversibility post-transplantation and the consequences of transplantation in patients with other causes of neurological disorders remain controversial, which supports the performance of an extensive work-up in expert centres for this subset of patients. The present guidelines assist clinicians in the diagnosis of the overt or covert form of HE to implement curative and preventive treatments and clarify which patients require referral to expert centres for consideration for liver transplantation. These guidelines are very clinically oriented and address different frequent clinical issues to help physicians make bedside decisions.

Lipocalin-2 Secreted by the Liver Regulates Neuronal Cell Function Through AKT-Dependent Signaling in Hepatic Encephalopathy Mouse Model

Hepatic encephalopathy (HE) associated with liver failure is accompanied by hyperammonemia, severe inflammation, depression, anxiety, and memory deficits as well as liver injury. Recent studies have focused on the liver-brain-inflammation axis to identify a therapeutic solution for patients with HE. Lipocalin-2 is an inflammation-related glycoprotein that is secreted by various organs and is involved in cellular mechanisms including iron homeostasis, glucose metabolism, cell death, neurite outgrowth, and neurogenesis. In this study, we investigated that the roles of lipocalin-2 both in the brain cortex of mice with HE and in Neuro-2a (N2A) cells. We detected elevated levels of lipocalin-2 both in the plasma and liver in a bile duct ligation mouse model of HE. We confirmed changes in cytokine expression, such as interleukin-1β, cyclooxygenase 2 expression, and iron metabolism related to gene expression through AKT-mediated signaling both in the brain cortex of mice with HE and N2A cells. Our data showed negative effects of hepatic lipocalin-2 on cell survival, iron homeostasis, and neurite outgrowth in N2A cells. Thus, we suggest that regulation of lipocalin-2 in the brain in HE may be a critical therapeutic approach to alleviate neuropathological problems focused on the liver-brain axis.

Impact of ammonia levels on outcome in clinically stable outpatients with advanced chronic liver disease

Background & Aims

Ammonia levels predicted hospitalisation in a recent landmark study not accounting for portal hypertension and systemic inflammation severity. We investigated (i) the prognostic value of venous ammonia levels (outcome cohort) for liver-related outcomes while accounting for these factors and (ii) its correlation with key disease-driving mechanisms (biomarker cohort).

Methods

(i) The outcome cohort included 549 clinically stable outpatients with evidence of advanced chronic liver disease. (ii) The partly overlapping biomarker cohort comprised 193 individuals, recruited from the prospective Vienna Cirrhosis Study (VICIS: NCT03267615).

Results

(i) In the outcome cohort, ammonia increased across clinical stages as well as hepatic venous pressure gradient and United Network for Organ Sharing model for end-stage liver disease (2016) strata and were independently linked with diabetes. Ammonia was associated with liver-related death, even after multivariable adjustment (adjusted hazard ratio [aHR]: 1.05 [95% CI: 1.00-1.10]; p = 0.044). The recently proposed cut-off (≥1.4 × upper limit of normal) was independently predictive of hepatic decompensation (aHR: 2.08 [95% CI: 1.35-3.22]; p <0.001), non-elective liver-related hospitalisation (aHR: 1.86 [95% CI: 1.17-2.95]; p = 0.008), and - in those with decompensated advanced chronic liver disease - acute-on-chronic liver failure (aHR: 1.71 [95% CI: 1.05-2.80]; p = 0.031). (ii) Besides hepatic venous pressure gradient, venous ammonia was correlated with markers of endothelial dysfunction and liver fibrogenesis/matrix remodelling in the biomarker cohort.

Conclusions

Venous ammonia predicts hepatic decompensation, non-elective liver-related hospitalisation, acute-on-chronic liver failure, and liver-related death, independently of established prognostic indicators including C-reactive protein and hepatic venous pressure gradient. Although venous ammonia is linked with several key disease-driving mechanisms, its prognostic value is not explained by associated hepatic dysfunction, systemic inflammation, or portal hypertension severity, suggesting direct toxicity.

Impact and implications

A recent landmark study linked ammonia levels (a simple blood test) with hospitalisation/death in individuals with clinically stable cirrhosis. Our study extends the prognostic value of venous ammonia to other important liver-related complications. Although venous ammonia is linked with several key disease-driving mechanisms, they do not fully explain its prognostic value. This supports the concept of direct ammonia toxicity and ammonia-lowering drugs as disease-modifying treatment.

S100B Protein but Not 3-Nitrotyrosine Positively Correlates with Plasma Ammonia in Patients with Inherited Hyperammonemias: A New Promising Diagnostic Tool?

Individuals with inherited hyperammonemias often present developmental and intellectual deficiencies which are likely to be exaggerated by hyperammonemia episodes in long-term outcomes. In order to find a new, systemic marker common to the course of congenital hyperammonemias, we decided to measure the plasma level of S100 calcium-binding protein B (S100B), which is associated with cerebral impairment. Further, we analyzed three mechanistically diverged but linked with oxidative-nitrosative stress biochemical parameters: 3-nitrotyrosine (3-NT), a measure of plasma proteins' nitration; advanced oxidation protein products (AOPP), a measure of protein oxidation; and glutathione peroxidase (GPx) activity, a measure of anti-oxidative enzymatic capacity. The plasma biomarkers listed above were determined for the first time in congenital hyperammonemia. Also, the level of pro- and anti-inflammatory mediators (i.e., IL-12, IL-6, IL-8, TNF-α, IL-1β, and IL-10) and chemokines (IP-10, MCP-1, MIG, and RANTES) were quantified. S100B was positively correlated with plasma ammonia level, while noticeable levels of circulating 3-NT in some of the patients' plasma did not correlate with ammonia concentration. Overall, the linear correlation between ammonia and S100B but not standard oxidative stress-related markers offers a unique perspective for the future identification and monitoring of neurological deficits risk-linked with hyperammonemia episodes in patients with inherited hyperammonemias. The S100B measure may support the development of therapeutic targets and clinical monitoring in these disorders.

Current approaches to hepatic encephalopathy

Hepatic encephalopathy (HE) is a brain dysfunction caused by liver insufficiency and/or portosystemic shunts. Between 30%-40% of patients with cirrhosis will present overt HE during their lifetime. While the pathophysiology of HE is not entirely understood, three critical factors have been identified: hyperammonaemia, systemic inflammation and oxidative stress by glutaminase gene alterations. Minimal HE is defined by the presence of signs of cognitive abnormalities in a patient without asterixis or disorientation; it can only be diagnosed with neuropsychological or psychometric tests. The diagnosis of overt HE is based on clinical examination with clinical scales. Currently, only overt HE should be routinely treated. The aims of treatment in an acute episode should be to improve the mental status, identify and treat the precipitating factor, reduce duration and limit consequences. Treatment strategies are targeted at reducing ammonia production and/or increasing its elimination. Even though minimal HE has negative effects on the patient's quality of life and effects on prognosis, indications for treatment are still controversial. There are still many unanswered questions regarding the pathophysiology and management of HE. We should also endeavor to develop more accurate and objective diagnostic methods for overt HE that would permit early detection and help improve outcomes on quality of life and economic burden.

A mouse model of hepatic encephalopathy: bile duct ligation induces brain ammonia overload, glial cell activation and neuroinflammation

Hepatic encephalopathy (HE) is a common complication of chronic liver disease, characterized by an altered mental state and hyperammonemia. Insight into the brain pathophysiology of HE is limited due to a paucity of well-characterized HE models beyond the rat bile duct ligation (BDL) model. Here, we assess the presence of HE characteristics in the mouse BDL model. We show that BDL in C57Bl/6j mice induces motor dysfunction, progressive liver fibrosis, liver function failure and hyperammonemia, all hallmarks of HE. Swiss mice however fail to replicate the same phenotype, underscoring the importance of careful strain selection. Next, in-depth characterisation of metabolic disturbances in the cerebrospinal fluid of BDL mice shows glutamine accumulation and transient decreases in taurine and choline, indicative of brain ammonia overload. Moreover, mouse BDL induces glial cell dysfunction, namely microglial morphological changes with neuroinflammation and astrocyte reactivity with blood-brain barrier (BBB) disruption. Finally, we identify putative novel mechanisms involved in central HE pathophysiology, like bile acid accumulation and tryptophan-kynurenine pathway alterations. Our study provides the first comprehensive evaluation of a mouse model of HE in chronic liver disease. Additionally, this study further underscores the importance of neuroinflammation in the central effects of chronic liver disease.

Blood ammonia in patients with chronic liver diseases: A better defined role in clinical practice

Ammonia is one of the main players in the pathogenesis of hepatic encephalopathy (HE) in patients with chronic liver diseases. The usefulness of measuring ammonemia has been debated since many years. New data reveal that besides helping in the differential diagnosis of HE, ammonemia could be a prognostic marker not only in patients with HE, but also in patients without any neurological symptoms, suggesting a potential toxic role of ammonia beyond the brain. Finally, targeting ammonemia while monitoring therapeutic response could be a way to improve outcomes in patients with HE.

EASL Clinical Practice Guidelines on the management of hepatic encephalopathy

The EASL Clinical Practice Guidelines (CPGs) on the management of hepatic encephalopathy (HE) present evidence-based answers to a set of relevant questions (where possible, formulated in PICO [patient/population, intervention, comparison and outcomes] format) on the definition, diagnosis, differential diagnosis and treatment of HE. The document does not cover the pathophysiology of HE and does not cover all available treatment options. The methods through which it was developed and any information relevant to its interpretation are also provided.

Metabolomics profiles in acute-on-chronic liver failure: Unveiling pathogenesis and predicting progression

Acute-on-chronic liver failure (ACLF) usually develops based on acute decompensation (AD) of cirrhosis and is characterized by intense systemic inflammation, multiple organ failure, and high short-term mortality. Validated biomarkers for the diagnosis and prognosis of ACLF remain to be clarified. Metabolomics is an emerging method used to measure low-molecular-weight metabolites and is currently frequently implemented to understand pathophysiological processes involved in disease progression, as well as to search for new diagnostic or prognostic biomarkers of various disorders. The characterization of metabolites in ACLF has recently been described via metabolomics. The role of metabolites in the pathogenesis of ACLF deserves further investigation and improvement and could be the basis for the development of new diagnostic and therapeutic strategies. In this review, we focused on the contributions of metabolomics on uncovering metabolic profiles in patients with ACLF, the key metabolic pathways that are involved in the progression of ACLF, and the potential metabolite-associated therapeutic targets for ACLF.

Heretical thoughts into hepatic encephalopathy

Clinical progress in the development of new diagnostic modalities and therapeutic strategies for the management of patients with hepatic encephalopathy has lagged behind the vast knowledge that has been generated from basic studies. In this article, we critically assess matters that should be revisited, such as definition, classification, diagnosis and grading of hepatic encephalopathy, which are difficult to apply reproducibly using the current criteria. Many lines of investigation have confirmed that hepatic encephalopathy is irreversible in many patients and suggest the need for further studies focussing on mechanisms of neuronal injury and death, to guide future drug development for these patients. The clinical evidence behind using lactulose for all severities of hepatic encephalopathy, which is currently considered the standard of care, is poor and placebo-controlled trials for hepatic encephalopathy should be considered ethically sound. This expert opinion identifies current challenges in hepatic encephalopathy and highlights areas which require further debate and investigation in order to help advance the field both scientifically and clinically.

Hepatic encephalopathy

Hepatic encephalopathy (HE) is a prognostically relevant neuropsychiatric syndrome that occurs in the course of acute or chronic liver disease. Besides ascites and variceal bleeding, it is the most serious complication of decompensated liver cirrhosis. Ammonia and inflammation are major triggers for the appearance of HE, which in patients with liver cirrhosis involves pathophysiologically low-grade cerebral oedema with oxidative/nitrosative stress, inflammation and disturbances of oscillatory networks in the brain. Severity classification and diagnostic approaches regarding mild forms of HE are still a matter of debate. Current medical treatment predominantly involves lactulose and rifaximin following rigorous treatment of so-called known HE precipitating factors. New treatments based on an improved pathophysiological understanding are emerging.

Construction and comprehensive analysis of a lncRNA-mRNA interactive network to reveal a potential lncRNA for hepatic encephalopathy development

Little is known about the role of lncRNA-mRNA regulatory relationships in hepatic encephalopathy (HE). Here, we aimed to construct the potential lncRNA and mRNA interactive network in forecasting HE development in patients with liver cirrhosis using different bioinformatic analysis method. Through analyses, we found that AL137857.1 had the most connections with other mRNAs and was deemed as a hub lncRNA. It was obviously upregulated in HE patients, which was also validated by another independent dataset. GO and KEGG analyses suggested that AL137857.1 was involved in microglial cell activation, phagocytosis, cytokine biosynthetic process, interleukin-6 production and tumor necrosis factor production. In vitro experiments suggested LPS could stimulate microglia to generate AL137857.1. In addition, we found that inhibition of AL137857.1 suppressed the expression of a series of inflammatory cytokines, including IL-1, IL-6, TNF-α, Cox2 and iNOS. Conversely, AL137857.1 over-expression induced a marked increase in these factors. Finally, AL137857.1 was demonstrated to be highly associated with the ability of microglial phagocytosis. Taken together, we have constructed a lncRNA-mRNA regulatory network associated with HE and explored the biological significance of mRNAs in the network, then discovered a novel lncRNA AL137857.1 in HE that might act as a potential regulator of the downstream inflammatory cytokines.

L-ornithine L-aspartate in acute treatment of severe hepatic encephalopathy: A double-blind randomized controlled trial

BACKGROUND AND AIMS

Data on the use of intravenous L-ornithine L-aspartate (LOLA) in the treatment of overt HE (OHE) is limited. We evaluated the role of intravenous LOLA in patients of cirrhosis with OHE grade III-IV.

APPROACH AND RESULTS

In a double-blind randomized placebo-controlled trial, 140 patients were randomized to a combination of LOLA, lactulose, and rifaximin (n = 70) or placebo, lactulose, and rifaximin (n = 70). LOLA was given as continuous intravenous infusion at a dose of 30 g over 24 h for 5 days. Ammonia levels, TNF-α, ILs, and endotoxins were measured on days 0 and 5. The primary outcome was the improvement in the grade of HE at day 5. Higher rates of improvement in grade of HE (92.5% vs. 66%, p < 0.001), lower time to recovery (2.70 ± 0.46 vs. 3.00 ± 0.87 days, p = 0.03), and lower 28-day mortality (16.4% vs. 41.8%, p = 0.001) were seen in the LOLA group as compared with placebo. Levels of inflammatory markers were reduced in both groups. Significantly higher reductions in levels of blood ammonia, IL-6, and TNF-α were seen in the LOLA group.

CONCLUSIONS

Combination of LOLA with lactulose and rifaximin was more effective than only lactulose and rifaximin in improving grades of HE, recovery time from encephalopathy, with lower 28-day mortality.

Overt hepatic encephalopathy is an independent risk factor for de novo infection in cirrhotic patients with acute decompensation

BACKGROUND

The occurrence of overt hepatic encephalopathy (OHE) is associated with increased mortality. HE is commonly precipitated by infection, but whether HE predisposes to new infection is unclear. This study aimed to test if OHE predisposes to de novo infection during hospitalisation and its association with short-term mortality.

AIMS AND METHODS

Seven hundred and fifty-nine consecutive patients were identified at two institutions from prospectively maintained clinical databases of cirrhotic patients admitted with acute decompensation (AD). Infection and HE data were collected on the day of admission, and the occurrence of de novo infections was assessed for 28 days after admission. EASL-CLIF organ failure criteria were used to determine the presence of organ failures. Multivariable analysis using the logistic regression model was used to assess predictors of 28-day mortality and de novo infection.

RESULTS

Patients were divided into four groups; no baseline OHE or infection (n = 352); OHE with no baseline Infection (n = 221); no OHE but baseline infection (n = 100) and OHE with baseline infection (n = 86). On multivariate analyses, OHE (OR, 1.532 [95% CI, 1.061-2.300, P = 0.024]), and admission to ITU (OR, 2.303 [95% CI, 1.508-3.517, P < 0.001]) were independent risk factors for de novo infection. 28-day mortality was 25.3%, 60.2%, 55.0% and 72.1% in the 4-groups respectively. Age, INR and creatinine were independently predictive of mortality. The presence of overt HE, infection, coagulation, kidney, circulatory, respiratory and liver failures were significantly associated with higher mortality.

CONCLUSION

OHE is an independent risk factor for de novo infection in cirrhotic patients with AD.

Insight into microRNAs-Mediated Communication between Liver and Brain: A Possible Approach for Understanding Acute Liver Failure?

Acute liver failure (ALF) is a life-threatening consequence of hepatic function rapid loss without preexisting liver disease. ALF may result in a spectrum of neuropsychiatric symptoms that encompasses cognitive impairment, coma, and often death, collectively defined as acute hepatic encephalopathy. Micro RNAs are small non-coding RNAs that modulate gene expression and are extensively verified as biomarker candidates in various diseases. Our systematic literature review based on the last decade's reports involving a total of 852 ALF patients, determined 205 altered circulating miRNAs, of which 25 miRNAs were altered in the blood, regardless of study design and methodology. Selected 25 miRNAs, emerging predominantly from the analyses of samples obtained from acetaminophen overdosed patients, represent the most promising biomarker candidates for a diagnostic panel for symptomatic ALF. We discussed the role of selected miRNAs in the context of tissue-specific origin and its possible regulatory role for molecular pathways involved in blood-brain barrier function. The defined several common pathways for 15 differently altered miRNAs were relevant to cellular community processes, indicating loss of intercellular, structural, and functional components, which may result in blood-brain barrier impairment and brain dysfunction. However, a causational relationship between circulating miRNAs differential expression, and particular clinical features of ALF, has to be demonstrated in a further study.

Mitochondrial Dysfunction in Advanced Liver Disease: Emerging Concepts

Mitochondria are entrusted with the challenging task of providing energy through the generation of ATP, the universal cellular currency, thereby being highly flexible to different acute and chronic nutrient demands of the cell. The fact that mitochondrial diseases (genetic disorders caused by mutations in the nuclear or mitochondrial genome) manifest through a remarkable clinical variation of symptoms in affected individuals underlines the far-reaching implications of mitochondrial dysfunction. The study of mitochondrial function in genetic or non-genetic diseases therefore requires a multi-angled approach. Taking into account that the liver is among the organs richest in mitochondria, it stands to reason that in the process of unravelling the pathogenesis of liver-related diseases, researchers give special focus to characterizing mitochondrial function. However, mitochondrial dysfunction is not a uniformly defined term. It can refer to a decline in energy production, increase in reactive oxygen species and so forth. Therefore, any study on mitochondrial dysfunction first needs to define the dysfunction to be investigated. Here, we review the alterations of mitochondrial function in liver cirrhosis with emphasis on acutely decompensated liver cirrhosis and acute-on-chronic liver failure (ACLF), the latter being a form of acute decompensation characterized by a generalized state of systemic hyperinflammation/immunosuppression and high mortality rate. The studies that we discuss were either carried out in liver tissue itself of these patients, or in circulating leukocytes, whose mitochondrial alterations might reflect tissue and organ mitochondrial dysfunction. In addition, we present different methodological approaches that can be of utility to address the diverse aspects of hepatocyte and leukocyte mitochondrial function in liver disease. They include assays to measure metabolic fluxes using the comparatively novel Biolog’s MitoPlates in a 96-well format as well as assessment of mitochondrial respiration by high-resolution respirometry using Oroboros’ O2k-technology and Agilent Seahorse XF technology.

Role of lactulose for prophylaxis against hepatic encephalopathy in cirrhotic patients with upper gastrointestinal bleeding: A randomized trial

BACKGROUND

We aimed to assess the efficacy of lactulose as prophylaxis against hepatic encephalopathy (HE) in cirrhotic patients with acute upper gastrointestinal bleeding (AUGIB).

METHODS

We conducted a randomized, double-blinded, placebo-controlled, multicenter study from October 2012 to February 2014. Cirrhotic patients presenting with AUGIB (aged 18-80 years, without HE at the time of admission) were enrolled and randomized to receive blinded medications (both physically indistinguishable), labeled "Lactulose A" and "Lactulose B" for 5 days along with standard treatment depending on the type of bleeding (variceal and nonvariceal). The primary endpoint was the development of overt HE according to the West-Haven criteria. Modified intention-to-treat analysis was performed.

RESULTS

Forty-six patients completed the protocol: Lactulose A (placebo, n = 22) and Lactulose B (lactulose, n = 24). There was no significant difference in baseline characteristics and clinical outcomes between the two groups. Nine (19.6%) patients developed HE: five (22.7%) in the placebo group and four (16.7%) in the lactulose group (p = 0.718). One patient (2.2%) died in lactulose group. All patients tolerated the medication and no significant difference in adverse effects was detected (59.1% in placebo vs. 50.0% in lactulose group, p = 0.536). On multivariate analysis, increased baseline Child-Turcotte-Pugh (CTP) score (odds ratio [OR] 2.176; 95% confidence interval [CI] 1.012-4.681, p = 0.047) and presence of diarrhea (OR 16.261; 95% CI 1.395-189.608, p = 0.026) were independent risk factors for the development of HE.

CONCLUSION

Five-day lactulose is ineffective as prophylaxis against HE in cirrhotic patients with AUGIB. Unnecessary treatment with laxatives should be avoided in these patients.

TRIAL REGISTRATION

Clinical trial registry number TCTR20200526003 (retrospectively registered).

Optimization of an ammonia assay based on transmembrane pH-gradient polymersomes

Reliable ammonia quantification assays are essential for monitoring ammonemia in patients with liver diseases. In this study, we describe the development process of a microplate-based assay for accurate, precise, and robust ammonia quantification in biological fluids, following regulatory guidelines on bioanalytical method validation. The assay is based on transmembrane pH-gradient polymersomes that encapsulate a pH-sensitive ratiometric fluorophore, the fluorescence signal of which correlates with the ammonia concentration in the sample. Using a four-parameter logistic regression, the assay had a large quantification range (30–800 μM ammonia). As for selectivity, the presence of amino acids or pyruvate (up to clinically relevant concentrations) showed no assay interference. In samples with low bilirubin levels, polymersomes containing the fluorophore pyranine provided accurate ammonia quantification. In samples with high bilirubin concentrations, billirubin’s optical interference was alleviated when replacing pyranine with a close to near-infrared hemicyanine fluorophore. Finally, the assay could correctly retrieve the ammonia concentration in ammonia-spiked human plasma samples, which was confirmed by comparing our measurements with the data obtained using a commercially available point-of-care device for ammonia.

Impact of non-hepatic hyperammonemia on mortality in intensive care unit patients: a retrospective cohort study

BACKGROUND/AIMS

The effect of hyperammonemia on the mortality in patients with liver cirrhosis is well documented. However, little is known about the impact of hyperammonemia on mortality among intensive care unit patients without hepatic disease. We aimed to investigate factors associated with non-hepatic hyperammonemia among intensive care unit patients and to evaluate the factors related to the 7- and 90-day mortality.

METHODS

Between February 2016 and February 2020, 948 patients without hepatic disease who had 972 episodes of admission to the intensive care unit were retrospectively enrolled and classified as hyperammonemia grades 0 (≤ 80 µg/dL; 585 [60.2%]), 1 (≤ 160 µg/dL; 291 [29.9%]), 2 (≤ 240 µg/dL; 55 [5.7%]), and 3 (> 240 µg/dL; 41 [4.2%]). Factors associated with hyperammonemia and the 7- and 90-day mortality were evaluated by multivariate logistic regression analysis and Cox regression analysis, respectively. Kaplan-Meier survival curves for the 7- and 90-day mortality were constructed.

RESULTS

The independent risk factors for hyperammonemia were male sex (odds ratio, 1.517), age (0.984/year), acute brain failure (2.467), acute kidney injury (1.437), prothrombin time-international normalized ratio (2.272/unit), and albumin (0.694/g/dL). The 90-day mortality rate in the entire cohort was 24.3% and gradually increased with increasing hyperammonemia grade at admission (17.9%, 28.2%, 43.6%, and 61.0% in patients with grades 0, 1, 2, and 3, respectively). Additionally, non-hepatic hyperammonemia was an independent predictor of the 90- day mortality in intensive care unit patients.

CONCLUSION

Non-hepatic hyperammonemia is common (39.8%) and associated with the 90-day mortality among intensive care unit patients.

The neurogliovascular unit in hepatic encephalopathy

Hepatic encephalopathy (HE) is a neurological complication of hepatic dysfunction and portosystemic shunting. It is highly prevalent in patients with cirrhosis and is associated with poor outcomes. New insights into the role of peripheral origins in HE have led to the development of innovative treatment strategies like faecal microbiota transplantation. However, this broadening of view has not been applied fully to perturbations in the central nervous system. The old paradigm that HE is the clinical manifestation of ammonia-induced astrocyte dysfunction and its secondary neuronal consequences requires updating. In this review, we will use the holistic concept of the neurogliovascular unit to describe central nervous system disturbances in HE, an approach that has proven instrumental in other neurological disorders. We will describe HE as a global dysfunction of the neurogliovascular unit, where blood flow and nutrient supply to the brain, as well as the function of the blood-brain barrier, are impaired. This leads to an accumulation of neurotoxic substances, chief among them ammonia and inflammatory mediators, causing dysfunction of astrocytes and microglia. Finally, glymphatic dysfunction impairs the clearance of these neurotoxins, further aggravating their effect on the brain. Taking a broader view of central nervous system alterations in liver disease could serve as the basis for further research into the specific brain pathophysiology of HE, as well as the development of therapeutic strategies specifically aimed at counteracting the often irreversible central nervous system damage seen in these patients.

Lactate and blood ammonia on admission as biomarkers to predict the prognosis of patients with acute mushroom poisoning and liver failure: a retrospective study

The diagnosis of liver damage induced by mushroom poisoning is still challenging. This study aims to screen the early biological indexes that could predict acute mushroom poisoning with liver damage. The patients with acute mushroom poisoning and liver damage admitted to The First Affiliated Hospital of Dalian Medical University，China from July 2007 to August 2017 were analyzed retrospectively. A total of 66 patients were enrolled in this study, with 44 and 22 patients in the liver injury group and liver failure group, respectively. Ten patients in the liver failure group died, with a mortality of 45.5% in this group. Multivariable Cox regression showed that the blood ammonia (NH3) and lactic acid (Lac) at the time of admission were independently associated with the in-hospital time to death for patients with liver failure induced by mushroom poisoning. Lactate and blood ammonia at the time of admission could be used to predict the prognosis of patients with acute mushroom poisoning and liver failure.