Acute-on-Chronic Liver Failure: A New Disease or an Old One Hiding in Plain Sight?

Liquid Liver Biopsy for Disease Diagnosis and Prognosis

Liver diseases are a major burden worldwide, the scope of which is expected to further grow in the upcoming years. Clinically relevant liver dysfunction-related blood markers such as alanine aminotransferase and aspartate aminotransferase have limited accuracy. Nowadays, liver biopsy remains the gold standard for several liver-related pathologies, posing a risk of complication due to its invasive nature. Liquid biopsy is a minimally invasive approach, which has shown substantial potential in the diagnosis, prognosis, and monitoring of liver diseases by detecting disease-associated particles such as proteins and RNA molecules in biological fluids. Histones are the core components of the nucleosomes, regulating essential cellular processes, including gene expression and DNA repair. Following cell death or activation of immune cells, histones are released in the extracellular space and can be detected in circulation. Histones are stable in circulation, have a long half-life, and retain their post-translational modifications. Here, we provide an overview of the current research on histone-mediated liquid biopsy methods for liver diseases, with a focus on the most common detection methods.

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

Hepatic encephalophathy (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.

The Clinical Spectrum and Manifestations of Acute-on-Chronic Liver Failure

Acute-on-chronic liver failure (ACLF) is characterized by abrupt decompensation in a patient with chronic liver disease with extrahepatic organ dysfunction and is implicated in an increased risk of mortality. ACLF may be present in approximately 20% to 40% of hospitalized cirrhosis. There are several diagnostic scoring systems for ACLF; one defined by the North American Consortium for Study of End-stage Liver Disease is the presence of acutely decompensated cirrhosis complicated by failure of two or more organ systems: circulatory, renal, neurological, coagulopathy, and/or pulmonary.

Acute kidney injury in patients with acute-on-chronic liver failure: clinical significance and management

Acute-on-chronic-liver failure (ACLF) refers to a phenomenon in which patients with chronic liver disease develop multiple organ failure due to acute exacerbation of underlying liver disease. More than 10 definitions of ACLF are extant around the world, and there is lack of consensus on whether extrahepatic organ failure is a main component or a consequence of ACLF. Asian and European consortiums have their own definitions of ACLF. The Asian Pacific Association for the Study of the Liver ACLF Research Consortium does not consider kidney failure as a diagnostic criterion for ACLF. Meanwhile, the European Association for the Study of the Liver Chronic Liver Failure and the North American Consortium for the Study of End-stage Liver Disease do consider kidney failure as an important factor in diagnosing and assessing the severity of ACLF. When kidney failure occurs in ACLF patients, treatment varies depending on the presence and stage of acute kidney injury (AKI). In general, the diagnosis of AKI in cirrhotic patients is based on the International Club of Ascites criteria: an increase of 0.3 mg/dL or more within 48 hours or a serum creatinine increase of 50% or more within one week. This study underscores the importance of kidney failure or AKI in patients with ACLF by reviewing its pathophysiology, prevention methods, and treatment approaches.

Evolution of non-thyroidal illness syndrome in acute decompensation of liver cirrhosis and acute-on-chronic liver failure

BACKGROUND AND AIMS

Non-thyroidal illness syndrome (NTIS) is frequent in critically ill patients and associated with adverse outcomes. We aimed to characterize the evolution of NTIS in patients with acute decompensation (AD) of cirrhosis and acute-on-chronic liver failure (ACLF), since NTIS is not well described in these newly defined syndromes.

METHODS

Thyroid hormones (TH) were quantified at baseline in consecutive patients with cirrhosis. In addition, 76 inflammatory mediators were quantified by proximity extension analysis assay in a subgroup of patients. Associations between TH, cirrhosis stage, mortality and inflammation were assessed.

RESULTS

Overall, 437 patients were included, of whom 165 (37.8%), 211 (48.3%), and 61 (14%) had compensated cirrhosis (CC), AD, and ACLF. FT₃ concentrations were lower in AD versus CC, and further decreased in ACLF. Importantly, NTIS was present in 83 (39.3%) patients with AD and in 44 (72.1%) patients with ACLF (P<0.001). Yet, TSH and TSH-based indexes (TSH/FT₃-ratio, thyroid index) showed an U-shaped evolution during progression of cirrhosis, suggesting a partially preserved responsiveness of the hypothalamus and pituitary in AD. Infections were associated with lower FT₃ concentrations in AD, but not in ACLF. Low FT₃ concentrations correlated significantly with 90-day mortality. Both, AD/ACLF and NTIS, were associated with signatures of inflammatory mediators, which were partially non-overlapping.

CONCLUSION

NTIS is frequent already in AD and therefore precedes critically illness in a subgroup of patients with decompensated cirrhosis. This might constitute a new paradigm of TH signaling in cirrhosis, offering opportunities to explore preventive effects of TH in AD.

Alcohol and Acute-on-Chronic Liver Failure

Acute-on-chronic liver failure (ACLF) is a clinical syndrome that occurs in patients with cirrhosis and is characterised by acute deterioration, organ failure and high short-term mortality. Alcohol is one of the leading causes of ACLF and the most frequently reported aetiology of underlying chronic liver disease. Among patients with alcoholic hepatitis (AH), ACLF is a frequent and severe complication. It is characterised by both immune dysfunction associated to an increased risk of infection and high-grade systemic inflammation that ultimately induce organ failure. Diagnosis and severity of ACLF determine AH prognosis, and therefore, ACLF prognostic scores should be used in severe AH with organ failure. Corticosteroids remain the first-line treatment for severe AH but they seem insufficient when ACLF is associated. Novel therapeutic targets to contain the excessive inflammatory response and reduce infection have been identified and are under investigation. With liver transplantation remaining one of the most effective therapies for severe AH and ACLF, adequate organ allocation represents a growing challenge. Hence, a clear understanding of the pathophysiology, clinical implications and management strategies of ACLF in AH is essential for hepatologists, which is narrated briefly in this review.

Animal models applied to acute-on-chronic liver failure: Are new models required to understand the human condition?

The liver is a multifaceted organ; its location and detoxifying function expose this organ to countless injuries. Acute-on-chronic failure liver (ACLF) is a severe syndrome that affects the liver due to acute decompensation in patients with chronic liver disease. An infection environment, ascites, increased liver enzymes and prothrombin time, encephalopathy and fast-evolving multiorgan failure, leading to death, usually accompany this. The pathophysiology remains poorly understand. In this context, animal models become a very useful tool in this regard, as understanding; the disease may be helpful in developing novel therapeutic methodologies for ACLF. However, although animal models display several similarities to the human condition, they do not represent all ACLF manifestations, resulting in significant challenges. An initial liver cirrhosis framework followed by the induction of an acute decompensation by administering lipopolysaccharide and D-GaIN, potentiating liver damage supports the methodologies applied to induce experimental ACLF. The entire methodology has been described mostly for rats. Nevertheless, a quick PubMed database search indicates about 30 studies concerning ACFL models and over 1000 regarding acute liver failure models. These findings demonstrate the clear need to establish easily reproducible ACFL models to elucidate questions about this quickly established and often fatal syndrome.

Animal models applied to acute-on-chronic liver failure: Are new models required to understand the human condition?

The liver is a multifaceted organ; its location and detoxifying function expose this organ to countless injuries. Acute-on-chronic failure liver (ACLF) is a severe syndrome that affects the liver due to acute decompensation in patients with chronic liver disease. An infection environment, ascites, increased liver enzymes and prothrombin time, encephalopathy and fast-evolving multiorgan failure, leading to death, usually accompany this. The pathophysiology remains poorly understand. In this context, animal models become a very useful tool in this regard, as understanding; the disease may be helpful in developing novel therapeutic methodologies for ACLF. However, although animal models display several similarities to the human condition, they do not represent all ACLF manifestations, resulting in significant challenges. An initial liver cirrhosis framework followed by the induction of an acute decompensation by administering lipopolysaccharide and D-GaIN, potentiating liver damage supports the methodologies applied to induce experimental ACLF. The entire methodology has been described mostly for rats. Nevertheless, a quick PubMed database search indicates about 30 studies concerning ACFL models and over 1000 regarding acute liver failure models. These findings demonstrate the clear need to establish easily reproducible ACFL models to elucidate questions about this quickly established and often fatal syndrome.

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.

Oxidative Stress-A Key Player in the Course of Alcohol-Related Liver Disease

Oxidative stress is known to be an inseparable factor involved in the presentation of liver disorders. Free radicals interfere with DNA, proteins, and lipids, which are crucial in liver metabolism, changing their expression and biological functions. Additionally, oxidative stress modifies the function of micro-RNAs, impairing the metabolism of hepatocytes. Free radicals have also been proven to influence the function of certain transcriptional factors and to alter the cell cycle. The pathological appearance of alcohol-related liver disease (ALD) constitutes an ideal example of harmful effects due to the redox state. Finally, ethanol-induced toxicity and overproduction of free radicals provoke irreversible changes within liver parenchyma. Understanding the underlying mechanisms associated with the redox state in the course of ALD creates new possibilities of treatment for patients. The future of hepatology may become directly dependent on the effective action against reactive oxygen species. This review summarizes current data on the redox state in the natural history of ALD, highlighting the newest reports on this topic.

Still 'dwelling in the possibility' - critical update on stem cell therapy for acute on chronic liver failure

Stem cells therapy could improve survival in patients with liver failure. Studies on stem cell therapy and related growth factors in decompensated cirrhosis has been on the forefront but has shown heterogenous results. Recent high-quality studies have shown a lack of efficacy and safety. Patients with acute-on-chronic liver failure (ACLF) are a unique group with high mortality in the short-term associated with rapid onset extrahepatic organ failures. In these patients, there is an urgent need to identify treatments that can improve liver cell function and mass, prevent sepsis/organ failure, ameliorate systemic inflammation, and increase transplant-free survival. Stem cells are a novel treatment in ACLF but with unclear efficacy and safety. In this narrative review, we discuss the basics of liver regeneration in patients with ACLF and update current clinical status of stem cell use in patients with ACLF for improving our understanding of future directions.