Amounts of bile acids and bilirubin removed during single-pass albumin dialysis in patients with liver failure

The contributions of bacteria metabolites to the development of hepatic encephalopathy

Over 20% of mortality during acute liver failure is associated with the development of hepatic encephalopathy (HE). Thus, HE is a complication of acute liver failure with a broad spectrum of neuropsychiatric abnormalities ranging from subclinical alterations to coma. HE is caused by the diversion of portal blood into systemic circulation through portosystemic collateral vessels. Thus, the brain is exposed to intestinal-derived toxic substances. Moreover, the strategies to prevent advancement and improve the prognosis of such a liver-brain disease rely on intestinal microbial modulation. This is supported by the findings that antibiotics such as rifaximin and laxative lactulose can alleviate hepatic cirrhosis and/or prevent HE. Together, the significance of the gut-liver-brain axis in human health warrants attention. This review paper focuses on the roles of bacteria metabolites, mainly ammonia and bile acids (BAs) as well as BA receptors in HE. The literature search conducted for this review included searches for phrases such as BA receptors, BAs, ammonia, farnesoid X receptor (FXR), G protein-coupled bile acid receptor 1 (GPBAR1 or TGR5), sphingosine-1-phosphate receptor 2 (S1PR2), and cirrhosis in conjunction with the phrase hepatic encephalopathy and portosystemic encephalopathy. PubMed, as well as Google Scholar, was the search engines used to find relevant publications.

Successful use of single-pass albumin dialysis in the correction of severe hyperbilirubinemia in a case of acute hepatitis E

INTRODUCTION

Acute liver failure (ALF) is a rare syndrome defined by the rapid loss of liver function in the absence of pre-existing liver disease, which may be secondary to hepatitis A virus, hepatitis E virus (HEV), or to drugs in about 50% of cases. Extracorporeal albumin dialysis enables the elimination of albumin-bound toxins that accumulate in liver failure.

METHODS

We report a case of ALF secondary to HEV associated with severe hyperbilirubinemia. Patient was treated with four consecutive sessions of single-pass albumin dialysis (SPAD) carried out setting the following parameters: time: 300 min, Qb: 60 mL/min, Qd: 800-1000 mL/min, dialysate containing 4% albumin, citrate: 3-4 mmol/L.

RESULT

SPAD documented good support of liver function. Bilirubin levels were reduced from 22 to 14 g/dL after four treatments. Pruritus was the first clinical sign of improvement.

CONCLUSION

SPAD system can represent a safe and effective therapeutic option.

Efficacy of hemoperfusion with Seraph-100 in series with single pass albumin dialysis in acute hepatitis B infection: A case report

Acute and acute-on-chronic liver failure is a cause of death in patients suffering from viral hepatitis, and many cases need liver transplantation. Infection from hepatitis B virus may range from asymptomatic to severe acute and fulminant hepatitis. In this setting, treatment is mainly supportive as there is no consensus on antiviral therapy based on non-nucleoside reverse transcriptase inhibitors. Single-pass albumin dialysis is a liver-support technique for patients suffering from liver failure, that has shown effectiveness in the removal of both water-soluble and albumin-bound toxins, which accumulate due to impairment of the liver's cleansing function. We report here the case of a 62-year-old male who presented with a severe acute hepatitis B infection, liver failure, and marked hyperbilirubinemia. Treatment with single-pass albumin dialysis combined with a hemoperfusion device was successful in improving clinical, physiological, and laboratory parameters.

Acute-on-chronic liver failure (ACLF) in 2022: have novel treatment paradigms already arrived?

INTRODUCTION

Acute-on-chronic failure (ACLF) is a recognized syndrome in patients with chronic liver disease and is characterized by acute decompensation, organ failure(s), and a high short-term mortality. ACLF is often triggered by ongoing alcohol consumption, gastrointestinal bleeding and/or infections, and is pathophysiologically characterized by uncontrolled systemic inflammation coupled with paradoxical immunoparesis. Patients with ACLF require prompt and early recognition. Management requires extensive utilization of clinical resources often including escalation to intensive care.

AREAS COVERED

Currently, there are no specific targeted treatments for established ACLF, and management revolves around treating underlying precipitants and providing organ support. In this article, we review the epidemiology and pathophysiology of ACLF and summarize recent advances in management strategies of this syndrome, focusing specifically on novel emerging therapies.

EXPERT COMMENTARY

ACLF is a challenging condition with rapid clinical course, high short-term mortality and varying clinical phenotypes. Management of ACLF is broadly focused on supportive care often in an intensive care setting with liver transplantation proving to be an increasingly relevant and effective rescue therapy. This disease has clear pathogenesis and epidemiological burden, thus distinguishing it from decompensated cirrhosis; there is clear clinical need for the development of specific and nuanced therapies to treat this condition.

The use of a single pass albumin dialysis for the management of liver failure

Introduction. A single pass albumin dialysis (SPAD) is a form of extracorporeal liver support system for removing albumin-bound toxins and water-soluble substances that accumulate in liver failure (LF). Case report. We presented three patients hospitalized for LF and treated using the SPAD at the University Clinical Center of Vojvodina, Serbia, from 2018 to 2019. Two of the patients presented with acute LF and one with acute-on-chronic LF. A total of 6 SPAD sessions were performed on each patient, resulting in decreased serum bilirubin and bile acid levels and hepatic encephalopathy grade. On discharge from the hospital, the liver function was improved in all the patients. Conclusion. SPAD removes the hepatotoxic substances without improvement of synthetic liver function. It represents a supportive treatment for LF patients who do not respond to the standard of care, offering a longer time for bridging to organ transplantation or spontaneous recovery of the liver function.

Extracorporeal Albumin Dialysis in Liver Failure with MARS and SPAD: A Randomized Crossover Trial

INTRODUCTION

Liver failure is associated with hepatic and extrahepatic organ failure leading to a high short-term mortality rate. Extracorporeal albumin dialysis (ECAD) aims to reduce albumin-bound toxins accumulated during liver failure. ECAD detoxifies blood using albumin dialysis through an artificial semipermeable membrane with recirculation (molecular adsorbent recirculating system, MARS) or without (single-pass albumin dialysis, SPAD).

METHODS

We performed a randomized crossover open trial in a surgical intensive care unit. The primary outcome of the study was total bilirubin reduction during MARS and during SPAD therapies. The secondary outcomes were conjugated bilirubin and bile acid level reduction during MARS and SPAD sessions and tolerance of dialysis system devices. Inclusion criteria were adult patients presenting liver failure with factor V activity <50% associated with bilirubin ≥250 μmol/L and a complication (either hepatic encephalopathy, severe pruritus, or hepatorenal syndrome). For MARS and SPAD, the dialysis flow rate was equal to 1,000 mL/h.

RESULTS

Twenty crossovers have been performed. Baseline biochemical characteristics (bilirubin, ammonia, bile acids, creatinine, and urea) were not statistically different between MARS and SPAD. Both ECAD have led to a significant reduction in total bilirubin (-83 ± 67 μmol/L after MARS; -122 ± 118 μmol/L after SPAD session), conjugated bilirubin (-82 ± 61 μmol/L after MARS; -105 ± 96 μmol/L after SPAD session), and bile acid levels (-64 ± 75 μmol/L after MARS; -56 ± 56 μmol/L after SPAD session), all nondifferent comparing MARS to SPAD.

CONCLUSION

A simple-to-perform SPAD therapy with equal to MARS dialysate flow parameters provides the same efficacy in bilirubin and bile acid removal. However, clinically relevant endpoints have to be evaluated in randomized trials to compare MARS and SPAD therapies and to define the place of SPAD in the liver failure care program.

Artificial liver support systems

Artificial liver systems are used to bridge between transplantation or to allow a patient's liver to recover. They are used in patients with acute liver failure (ALF) and acute-on-chronic liver failure. There are five artificial systems currently in use: molecular adsorbent recirculating system (MARS), single-pass albumin dialysis (SPAD), Prometheus, selective plasma filtration therapy, and hemodiafiltration. The aim is to compare existing data on the efficiency of these devices. A literature search was conducted using online libraries. Inclusion criteria included randomized control trials or comparative human studies published after the year 2000. A systematic review was conducted for the five individual devices with a more detailed comparison of the biochemistry for the SPAD and MARS systems. Eighty-nine patients were involved in the review comparing SPAD and MARS. Results showed that there was an average reduction in bilirubin (-53 μmol/L in MARS and -50 μmol/L in SPAD), creatinine (-19.5 μmol/L in MARS and -7.5 μmol/L in SPAD), urea (-0.9 mmol/L in MARS and -0.75 mmol/L in SPAD), and gamma-glutamyl transferase (-0.215 μmol/L·s in MARS and -0.295 μmol/L·s in SPAD) in both SPAD and MARS. However, there was no significant difference between the changes in the two systems. This review demonstrated that both MARS and SPAD aid recovery of ALF. There is no difference between the efficiency of MARS and SPAD. Because of the limited data, there is a need for more randomized control trials. Evaluating cost and patient preference would aid in differentiating the systems.

Continuous renal replacement therapy and extended indications

Extracorporeal blood purification (EBP) techniques provide support for critically ill patients with single or multiple organ dysfunction. Continuous renal replacement therapy (CRRT) is the modality of choice for kidney support for those patients and orchestrates the interactions between the different artificial organ support systems. Intensive care teams should be familiar with the concept of sequential extracorporeal therapy and plan on how to incorporate new treatment modalities into their daily practices. Importantly, scientific evidence should guide the decision-making process at the bedside and provide robust arguments to justify the costs of implementing new EBP treatments. In this narrative review, we explore the extended indications for CRRT as an adjunctive treatment to provide support for the heart, lung, liver, and immune system. We detail practicalities on how to run the treatments and how to tackle the most frequent complications regarding each of the therapies, whether applied alone or integrated. The physicochemical processes and technologies involved at the molecular level encompassing the interactions between the molecules, membranes, and resins are spotlighted. A clinical case will illustrate the timing for the initiation, maintenance, and discontinuation of EBP techniques.

Artificial liver support systems: what is new over the last decade?

The liver is a complex organ that performs vital functions of synthesis, heat production, detoxification and regulation; its failure carries a highly critical risk. At the end of the last century, some artificial liver devices began to develop with the aim of being used as supportive therapy until liver transplantation (bridge-to-transplant) or liver regeneration (bridge-to-recovery). The well-recognized devices are the Molecular Adsorbent Recirculating System™ (MARS™), the Single-Pass Albumin Dialysis system and the Fractionated Plasma Separation and Adsorption system (Prometheus™). In the following years, experimental works and early clinical applications were reported, and to date, many thousands of patients have already been treated with these devices. The ability of artificial liver support systems to replace the liver detoxification function, at least partially, has been proven, and the correction of various biochemical parameters has been demonstrated. However, the complex tasks of regulation and synthesis must be addressed through the use of bioartificial systems, which still face several developmental problems and very high production costs. Moreover, clinical data on improved survival are conflicting. This paper reviews the progress achieved and new data published on artificial liver support systems over the past decade and the prospects for these devices.

Bile Acid Signaling Pathways from the Enterohepatic Circulation to the Central Nervous System

Bile acids are best known as detergents involved in the digestion of lipids. In addition, new data in the last decade have shown that bile acids also function as gut hormones capable of influencing metabolic processes via receptors such as FXR (farnesoid X receptor) and TGR5 (Takeda G protein-coupled receptor 5). These effects of bile acids are not restricted to the gastrointestinal tract, but can affect different tissues throughout the organism. It is still unclear whether these effects also involve signaling of bile acids to the central nervous system (CNS). Bile acid signaling to the CNS encompasses both direct and indirect pathways. Bile acids can act directly in the brain via central FXR and TGR5 signaling. In addition, there are two indirect pathways that involve intermediate agents released upon interaction with bile acids receptors in the gut. Activation of intestinal FXR and TGR5 receptors can result in the release of fibroblast growth factor 19 (FGF19) and glucagon-like peptide 1 (GLP-1), both capable of signaling to the CNS. We conclude that when plasma bile acids levels are high all three pathways may contribute in signal transmission to the CNS. However, under normal physiological circumstances, the indirect pathway involving GLP-1 may evoke the most substantial effect in the brain.

Hepatic encephalopathy: a critical current review

Hepatic encephalopathy (HE) is a serious neuropsychiatric complication of cirrhosis and/or porto-systemic shunting. The clinical symptoms are widely variable, extending from subtle impairment in mental state to coma. The utility of categorizing the severity of HE accurately and efficiently serves not only to provide practical functional information about the current clinical status of the patient but also gives valuable prognostic information. In the past 20–30 years, there has been rapid progress in understanding the pathophysiological basis of HE; however, the lack of direct correlation between pathogenic factors and the severity of HE make it difficult to select appropriate therapy for HE patients. In this review, we will discuss the classification system and its limitations, the neuropsychometric assessments and their challenges, as well as the present knowledge on the pathophysiological mechanisms. Despite the many prevalent hypotheses around the pathogenesis of the disease, most treatments focus on targeting and lowering the accumulation of ammonia as well as inflammation. However, treatment of minimal HE remains a huge unmet need and a big concerted effort is needed to better define this condition to allow the development of new therapies. We review the currently available therapies and future approaches to treat HE as well as the scientific and clinical data that support their effectiveness.

Review of Extracorporeal Membrane Oxygenation and Dialysis-Based Liver Support Devices for the Use of Nephrologists

Acute kidney injury in the intensive care unit (ICU) is a manifestation of an underlying severe illness that commonly involves other organ systems. Pulmonary, cardiac, and hepatic failures are the most prevalent. This article provides a simplified review of the technical aspects of extracorporeal cardiopulmonary and liver support devices used in the adult ICU patient, as well as a summary of the most relevant and up-to-date clinical evidence that supports their use.

Molecular adsorbent recirculating system and single-pass albumin dialysis in liver failure--a prospective, randomised crossover study

Background

The aim of extracorporeal albumin dialysis (ECAD) is to reduce endogenous toxins accumulating in liver failure. To date, ECAD is conducted mainly with the Molecular Adsorbents Recirculating System (MARS). However, single-pass albumin dialysis (SPAD) has been proposed as an alternative. The aim of this study was to compare the two devices with a prospective, single-centre, non-inferiority crossover study design with particular focus on reduction of bilirubin levels (primary endpoint) and influence on paraclinical and clinical parameters (secondary endpoints) associated with liver failure.

Methods

Patients presenting with liver failure were screened for eligibility and after inclusion were randomly assigned to be started on either conventional MARS or SPAD (with 4 % albumin and a dialysis flow rate of 700 ml/h). Statistical analyses were based on a linear mixed-effects model.

Results

Sixty-nine crossover cycles of ECAD in 32 patients were completed. Both systems significantly reduced plasma bilirubin levels to a similar extent (MARS: median −68 μmol/L, interquartile range [IQR] −107.5 to −33.5, p = 0.001; SPAD: −59 μmol/L, −84.5 to +36.5, p = 0.001). However, bile acids (MARS: −39 μmol/L, −105.6 to −8.3, p < 0.001; SPAD: −9 μmol/L, −36.9 to +11.4, p = 0.131), creatinine (MARS: −24 μmol/L, −46.5 to −8.0, p < 0.001; SPAD: −2 μmol/L, −9.0 to +7.0/L, p = 0.314) and urea (MARS: −0.9 mmol/L, −1.93 to −0.10, p = 0.024; SPAD: −0.1 mmol/L, −1.0 to +0.68, p = 0.523) were reduced and albumin-binding capacity was increased (MARS: +10 %, −0.8 to +20.9 %, p < 0.001; SPAD: +7 %, −7.5 to +15.5 %, p = 0.137) only by MARS. Cytokine levels of interleukin (IL)-6 and IL-8 and hepatic encephalopathy were altered by neither MARS nor SPAD.

Conclusions

Both procedures were safe for temporary extracorporeal liver support. While in clinical practice routinely assessed plasma bilirubin levels were reduced by both systems, only MARS affected other paraclinical parameters (i.e., serum bile acids, albumin-binding capacity, and creatinine and urea levels). Caution should be taken with regard to metabolic derangements and electrolyte disturbances, particularly in SPAD using regional citrate anti-coagulation.

Trial registration

German Clinical Trials Register (www.drks.de) DRKS00000371. Registered 8 April 2010.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-1159-3) contains supplementary material, which is available to authorized users.

T helper cell dysregulation with hepatitis B and rebalance with glucocorticoids

AIM: To investigate T helper 17/regulatory T cell alterations in early severe hepatitis B and the effect of glucocorticoids.

METHODS: The study included 20 patients in the early stage of severe hepatitis B (SHB) and 11 healthy controls. All patients had elevated T helper 17 (Th17) levels, decreased regulatory T (Treg) cell levels, and significant Th17/Treg ratios.

RESULTS: After glucocorticoid treatment, 16 patients showed improvement with significant decreases in Th17 levels, increases in Treg, and rebalanced Th17/Treg ratios. The four patients who showed no improvement had increases in both Th17 and Treg levels and an even higher Th17/Treg ratio than before.

CONCLUSION: Glucocorticoid treatment can rectify Th17/Treg dysregulation in patients with SHB.

Bile acids permeabilize the blood brain barrier after bile duct ligation in rats via Rac1-dependent mechanisms

BACKGROUND

The blood brain barrier tightly regulates the passage of molecules into the brain and becomes leaky following obstructive cholestasis. The aim of this study was to determine if increased serum bile acids observed during cholestasis permeabilize the blood brain barrier.

METHODS

Rats underwent bile duct ligation or deoxycholic or chenodeoxycholic acid injections and blood brain barrier permeability assessed. In vitro, the permeability of rat brain microvessel endothelial cell monolayers, the expression and phosphorylation of occludin, ZO-1 and ZO-2 as well as the activity of Rac1 was assessed after treatment with plasma from cholestatic rats, or bile acid treatment, in the presence of a Rac1 inhibitor.

RESULTS

Blood brain barrier permeability was increased in vivo and in vitro following bile duct ligation or treatment with bile acids. Associated with the bile acid-stimulated increase in endothelial cell monolayer permeability was elevated Rac1 activity and increased phosphorylation of occludin. Pretreatment of endothelial cell monolayers with a Rac1 inhibitor prevented the effects of bile acid treatment on occludin phosphorylation and monolayer permeability.

CONCLUSIONS

These data suggest that increased circulating serum bile acids may contribute to the increased permeability of the blood brain barrier seen during obstructive cholestasis via disruption of tight junctions.