Outcome from molecular adsorbent recycling system (MARS) liver dialysis following drug-induced liver failure

Evaluating the Effect of Artificial Liver Support on Acute-on-Chronic Liver Failure Using the Quantitative Difference Algorithm: Retrospective Study

BACKGROUND

Liver failure, including acute-on-chronic liver failure (ACLF), occurs mainly in young adults and is associated with high mortality and resource costs. The prognosis evaluation is a crucial part of the ACLF treatment process and should run through the entire diagnosis process. As a recently proposed novel algorithm, the quantitative difference (QD) algorithm holds promise for enhancing the prognosis evaluation of ACLF.

OBJECTIVE

This study aims to examine whether the QD algorithm exhibits comparable or superior performance compared to the Model for End-Stage Liver Disease (MELD) in the context of prognosis evaluation.

METHODS

A total of 27 patients with ACLF were categorized into 2 groups based on their treatment preferences: the conventional treatment (n=12) and the double plasma molecular absorption system (DPMAS) with conventional treatment (n=15) groups. The prognosis evaluation was performed by the MELD and QD scoring systems.

RESULTS

A significant reduction was observed in alanine aminotransferase (P=.02), aspartate aminotransferase (P<.001), and conjugated bilirubin (P=.002), both in P values and QD value (Lτ>1.69). A significant decrease in hemoglobin (P=.01), red blood cell count (P=.01), and total bilirubin (P=.02) was observed in the DPMAS group, but this decrease was not observed in QD (Lτ≤1.69). Furthermore, there was a significant association between MELD and QD values (P<.001). Significant differences were observed between groups based on patients' treatment outcomes. Additionally, the QD algorithm can also demonstrate improvements in patient fatigue. DPMAS can reduce alanine aminotransferase, aspartate aminotransferase, and unconjugated bilirubin.

CONCLUSIONS

As a dynamic algorithm, the QD scoring system can evaluate the therapeutic effects in patients with ACLF, similar to MELD. Nevertheless, the QD scoring system surpasses the MELD by incorporating a broader range of indicators and considering patient variability.

The development of artificial livers

PURPOSE OF REVIEW

While liver transplantation is an established treatment for liver failure, the number of patients with liver failure amenable to such intervention far outnumbers the donor supply of livers. Technologies serving to bridge this gap are required. Artificial livers may serve as an alternative. In this review, we discuss the development of artificial liver technologies.

RECENT FINDINGS

The accrued clinical data suggest that current liver assist devices may serve a role in specific liver diseases, but for the most part no survival benefit has been demonstrated. More clinical trials are expected to elucidate their utilization. Simultaneously, recent advances in materials and tissue engineering are allowing for exciting developments for novel artificial livers.

SUMMARY

As there continues to be more clinical data regarding the use of current liver devices, new intricate artificial liver technologies, with the use of sophisticated three-dimensional materials, are being developed that may help improve outcomes of liver failure patients.

Glucocorticoid Regulates NLRP3 in Acute-On-Chronic Hepatitis B Liver Failure

Acute-on-chronic hepatitis B liver failure (ACHBLF) refers to the acute deterioration of liver function during chronic hepatitis B virus infection, and is associated with high mortality, with rapid progression to death. Nucleotide-binding oligomerisation domain-like receptors (NLRs) Family Pyrin Domain Containing 3(NLRP3) inflammasome contributed to the pathogenesis of D-galactosamine and lipopolysaccharide-induced acute liver failure. However, the profile of NLRP3 in patients with ACHBLF has not been demonstrated. This study was therefore conducted to investigate the expression of NLRP3 in patients with ACHBLF and identify the effect of glucocorticoid on NLRP3. We recruited 70 patients with ACHBLF undergoing glucocorticoid treatment for 28 days, 30 patients with chronic hepatitis B (CHB), and 24 healthy controls (HCs) in this study. The relative messenger RNA (mRNA) level of NLRP3 and related genes were measured by reverse transcription polymerase chain reaction, the plasma levels of interleukin-1β (IL-1β) and interleukin-18 (IL-18) were measured by enzyme-linked immunosorbent assay. The mRNA level of NLRP3 was significantly higher in patients with ACHBLF than in patients with CHB as well as HCs (P<0.05). The plasma levels of IL-1β and IL-18 in patients with ACHBLF were significantly higher than in patients with CHB and HCs (P<0.05). The relative mRNA level of NLRP3 in surviving patients decreased significantly compared with that in patients who did not survive after glucocorticoid treatment (P<0.05). In conclusion, NLRP3 increased in patients with ACHBLF. Glucocorticoid could downregulate the expression of NLRP3 in surviving patients with ACHBLF.

Acute-on-Chronic Liver Failure (ACLF) in Coastal Eastern India: "A Single-Center Experience"

BACKGROUND AND OBJECTIVES

Acute-On-Chronic liver failure (ACLF) is an emerging entity. The present study was undertaken to analyze the clinical profile and natural course of ACLF patients.

PATIENTS AND METHODS

ACLF was defined as per Asia Pacific Association for the Study of Liver consensus criteria 2009. Patients fulfilling these criteria with some deviations were included and prospectively evaluated for clinical profile, etiologies of acute decompensation (AD) and underlying chronic liver disease, and short-term natural course [3 months].

RESULTS

Out of 123 patients with ACLF (mean age: 45.83 ± 12.05 years; male:female 109:14), 45.53% cases had prior history of AD, and 54.47% presented for the first time as ACLF. Etiologies of cirrhosis were alcohol, cryptogenic, and chronic hepatitis B virus infection in 65.04%, 23.57%, and 11.38% cases, respectively. Recent history of alcohol intake (within 4 weeks) [42.27%] followed by bacterial infections [36.58%] were the common etiologic precipitants for AD. Only 87 (70.73%) out of 123 cases could be followed up for a duration of 3 months; 62 (71.26%) cases died by 3 months. Most deaths occurred in the alcoholics compared to nonalcoholics [(43/53) 81.13% vs. (19/34) 55.88%; P = 0.01]. No significant difference in mortality rate was observed between ACLF cases with history of prior AD compared to newly diagnosed ACLF cases [30/40 (75%) vs. 32/47 (68.09%); P = 0.477]. The prognostic markers [MELD, MELD-Na, CTP] were not significantly different between survivors and nonsurvivors.

CONCLUSION

ACLF patients in our population had high short-term mortality rates with majority of deaths in alcoholics. Alcohol intake and bacterial infections were mainly responsible for AD in our study.

Efficacy of coupled low-volume plasma exchange with plasma filtration adsorption in treating pigs with acute liver failure: A randomised study

BACKGROUND & AIMS

Extracorporeal blood purification systems for supportive therapy of liver failure are widely used. We developed a novel blood purification system, named Li's artificial liver system (Li-ALS), which couples low-volume plasma exchange (low-volume PE) with plasma filtration adsorption (PFA). This study aims to evaluate the efficacy of our novel system in pigs with acute liver failure (ALF).

METHODS

Thirty-two pigs were infused with D-galactosamine (1.3g/kg) to induce ALF. All animals were equally and randomly divided into four groups: the ALF control group received intensive care, the PFA group underwent five hour plasma recycling filtration and adsorption purification, the low-volume PE group received one hour low-volume PE, and the Li-ALS group underwent one hour low-volume PE, followed by five hour PFA. Intervention was initiated 36hours after drug administration. The efficacy of each treatment was assessed by survival time and improvement in hematological, biochemical, and immunohistological parameters.

RESULTS

Pigs in the Li-ALS group survived longer than those in the other groups (p<0.001, ALF control: 60±2h; PFA group: 74±2h; low-volume PE group: 75±2h; and Li-ALS group: 90±3h). Liver enzyme, bilirubin, bile acid and blood ammonia levels were decreased significantly after Li-ALS treatment, and increases in inflammatory cytokines were ameliorated. A higher hepatocyte regeneration index was also observed in the Li-ALS group.

CONCLUSION

Our novel Li-ALS could expedite liver regeneration and improve survival time; hence, it could be promising for treating ALF.

Liver support systems--a review

Liver failure is associated with a high morbidity and mortality rate and is the seventh leading cause of death worldwide. Orthotopic liver transplantation remains the definitive treatment; however, because of the limited number of available organs many patients expire while on the transplant list. Currently, there are no established means for providing liver support as a means of bridging patients to transplantation or allowing for recovery from liver injury. Analogous to the clinical situation of renal failure, there is great interest in developing liver support systems that replace the metabolic and waste removal functions of the liver. These support systems are of two general types: artificial and bioartificial livers. In this review, based on a presentation from the 57th American Society of Artificial Internal Organs Annual Meeting (Washington, D.C., June 2011), we review the current status of liver support systems.

Artificial liver support devices as treatment option for liver failure

Non-biological artificial liver support (ALS) devices aim to remove albumin-bound and water-soluble toxins arising as a result of liver failure. They do not directly improve the liver synthetic capacity. The currently most used devices combine haemodialysis with albumin dialysis (MARS) or plasma separation and filtration (Prometheus). These devices have been used as a treatment for different types of liver failure: acute liver failure, acute-on-chronic liver failure and primary non- or poor-function after liver transplantation. Overall these devices are found to be safe. The following beneficial effects have been documented: improvement of jaundice, amelioration of haemodynamic instability, reduction of portal hypertension, lowering of intracranial pressure and improvement of hepatic encephalopathy. However, recently multicentre controlled trials failed to show a beneficial effect on transplant-free survival. Therefore the use of these devices at present seems only justified as a bridge to liver transplantation.

Use of the molecular adsorbent recirculating system (MARS™) for the management of acute poisoning with or without liver failure

INTRODUCTION

There is an increasing interest in recent developments in bioartificial and non-bioartificial devices, so called extracorporeal liver assist devices, which are now used widely not only to increase drug elimination, but also to enhance the removal of endogenous substances in acute liver failure. Most of the non-bioartificial techniques are based on the principle of albumin dialysis. The objective is to remove albumin-bound substances that could play a role in the pathophysiology of acute liver failure by dialysing blood against an albumin-containing solution across a high flux permeable membrane. The most widely used device is the Molecular Adsorbent Recirculating System (MARS™).

METHODS

The relevant English and French literature was identified through Medline using the terms, 'molecular adsorbent recirculating system', 'MARS', 'acute liver failure', 'acute poisoning', 'intoxication'. This search identified 139 papers of which 48 reported on a toxic cause for the use of MARS™. Of these 48 papers, 39 specified the substance (eighteen different substances were identified); two papers reported on the same group of patients. BIOARTIFICIAL AND NON-BIOARTIFICIAL SYSTEMS: Bioartificial systems based on porcine hepatocytes incorporated in the extracorporeal circuit are no longer in use due to the possibility of porcine retroviral transmission to humans. Historically, experience with such devices was limited to a few cases of paracetamol poisoning. In contrast, an abundant literature exists for the non-bioartificial systems based on albumin dialysis. The MARS™ has been used more widely than other techniques, such as the one using fractionated plasma separation and adsorption (Prometheus™). All the extracorporeal liver assist devices are able to some extent to remove biological substances (ammonia, urea, creatinine, bilirubin, bile acids, amino acids, cytokines, vasoactive agents) but the real impact on the patient's clinical course has still to be determined. Improvement in cardiovascular or neurological dysfunction has been shown both in acute liver failure and acute-on-chronic liver failure but no impact on mortality has been reported. ACUTE POISONING WITH LIVER FAILURE: Randomized controlled trials are very limited in number and patients poisoned by paracetamol or Amanita phalloides are usually included for outcome analysis in larger groups of acute liver failure patients. Initial results look promising but should be confirmed. Beyond its effect in liver failure, MARS™ could also enhance the elimination of the drug or toxin responsible for the failure, as is described with paracetamol. ACUTE POISONING WITHOUT LIVER FAILURE: Extracorporeal liver assist devices have also been used to promote elimination of drugs that are highly protein bound. Data in various case reports confirm a high elimination of phenytoin, theophylline and diltiazem. However, definite conclusions on the toxicokinetic or clinical efficacy cannot be drawn.

CONCLUSIONS

Despite the lack of large multicentre randomized trials on the use of MARS™ in patients with acute liver failure, the literature shows clinical and biological benefit from this technique. In drug or toxin-induced acute liver failure, such as paracetamol or mushroom poisoning, MARS™ has been used extensively, confirming in a non-randomized fashion, the positive effect observed in the larger population of acute liver failure patients. Furthermore, as MARS™ has been shown in experimental studies to remove protein-bound substances, it is potentially a promising treatment for patients with acute poisoning from drugs that have high protein-binding capacity and are metabolized by the liver, especially, if they develop liver failure concomitantly.

Bench-to-beside review: acute-on-chronic liver failure - linking the gut, liver and systemic circulation

The concept of acute-on-chronic liver failure (ACLF) was introduced recently to describe a subset of patients with chronic liver disease presenting with profound deterioration of liver function and rapidly evolving multi-organ failure. ACLF is frequently accompanied by the development of severe inflammatory response syndrome and has a high mortality. To date, treatment options are limited and exclusively supportive. Over the last few years, some insights have been generated in the pathophysiology of ACLF. A key role for the interaction of innate immune dysfunction, enhanced bacterial translocation from the gut, and circulatory dysfunction has been proposed. In this respect, therapeutic strategies have been examined, with variable success, in experimental studies in animals and humans. This review focuses on potentially relevant pathophysiological elements in the development of ACLF and points out promising treatment modalities in ACLF.

Acute-on-chronic liver failure: extracorporeal liver assist devices

PURPOSE OF REVIEW

Acute-on-chronic liver failure (ACLF), a syndrome precipitated by acute liver injury in patients with advanced cirrhosis, is associated with multiorgan dysfunction and high rates of mortality. Liver support systems have been developed in an attempt to improve survival of patients with ACLF by providing a bridge until recovery of the native liver function.

RECENT FINDINGS

Nonbiological devices such as molecular adsorbent recirculating system (MARS) and fractionated plasma separation and adsorption (Prometheus) are effective in improving severe hepatic encephalopathy and cholestasis, have good safety and tolerability profiles and are frequently employed in patients with ACLD; however, randomized controlled trials (RCTs) failed to show improvement in survival. Biologic devices that incorporate hepatic cells in bioreactors are also under development. Recent data from pilot studies suggested improvement in survival rates in some groups of patients with ACLF; however, their effect on patient survival in RCT is still unknown.

SUMMARY

Liver support systems are safe and well tolerated when used in management of patients with ACLF. Their use should continue in controlled clinical trials to explore their role in bridging patients to liver transplantation or recovery in well defined patient groups.

Bridging Therapies and Liver Transplantation in Acute Liver Failure; 10 Years of MARS Experience from Finland

Acute liver failure is a life-threatening condition in the absence of liver transplantation option. The aetiology of liver failure is the most important factor determining the probability of native liver recovery and prognosis of the patient. Extracorporeal liver assist devices like MARS (Molecular Adsorbent Recirculating System) may buy time for native liver recovery or serve as bridging therapy to liver transplantation, with reduced risk of cerebral complications. MARS treatment may alleviate hepatic encephalopathy even in patients with a completely necrotic liver. Taking this into account, better prognostic markers than hepatic encephalopathy should be used to assess the need for liver transplantation in acute liver failure.

Intensive therapy of the patient with liver disease

Liver disease is a subject of increasing importance in the UK, with a steadily rising incidence. It is an important cause of death in young adults, and the initial presentation of liver disease is frequently complicated by critical illness.

Survival predictors in patients treated with a molecular adsorbent recirculating system

AIM: To identify prognostic factors for survival in patients with liver failure treated with a molecular adsorbent recirculating system (MARS).

METHODS: MARS is a liver-assisting device that has been used in the treatment of liver failure to enable native liver recovery, and as a bridge to liver transplantation (LTX). We analyzed the 1-year outcomes of 188 patients treated with MARS, from 2001 to 2007, in an intensive care unit specializing in liver disease. Demographic, clinical and laboratory parameters were recorded before and after each treatment. One-year survival and the number of LTXs were recorded. Logistic regression analysis was performed to determine factors predicting survival.

RESULTS: The study included 113 patients with acute liver failure (ALF), 62 with acute-on-chronic liver failure (AOCLF), 11 with graft failure (GF), and six with miscellaneous liver failure. LTX was performed for 29% of patients with ALF, 18% with AOCLF and 55% with GF. The overall 1-year survival rate was 74% for ALF, 27% for AOCLF, and 73% for GF. The poorest survival rate, 6%, was noted in non-transplanted patients with alcohol-related AOCLF and cirrhosis, whereas, patients with enlarged and steatotic liver had 55% survival. The etiology of liver failure was the most important predictor of survival (P < 0.0001). Other prognostic factors were encephalopathy (P = 0.001) in paracetamol-related ALF, coagulation factors (P = 0.049) and encephalopathy (P = 0.064) in non-paracetamol-related toxic ALF, and alanine aminotransferase (P = 0.013) and factor V levels (P = 0.022) in ALF of unknown etiology.

CONCLUSION: The etiology of liver disease was the most important prognostic factor. MARS treatment appears to be ineffective in AOCLF with end-stage cirrhosis without an LTX option.

Acute-on-chronic liver failure: consensus recommendations of the Asian Pacific Association for the study of the liver (APASL)

The Asian Pacific Association for the Study of the Liver (APASL) set up a working party on acute-on-chronic liver failure (ACLF) in 2004, with a mandate to develop consensus guidelines on various aspects of ACLF relevant to disease patterns and clinical practice in the Asia-Pacific region. Experts predominantly from the Asia-Pacific region constituted this working party and were requested to identify different issues of ACLF and develop the consensus guidelines. A 2-day meeting of the working party was held on January 22-23, 2008, at New Delhi, India, to discuss and finalize the consensus statements. Only those statements that were unanimously approved by the experts were accepted. These statements were circulated to all the experts and subsequently presented at the Annual Conference of the APASL at Seoul, Korea, in March 2008. The consensus statements along with relevant background information are presented in this review.

The effect of molecular adsorbent recirculating system treatment on survival, native liver recovery, and need for liver transplantation in acute liver failure patients

Acute liver failure (ALF) is a medical emergency. Molecular adsorbent recirculating system (MARS), an artificial liver support system, can partly compensate for the detoxifying function of the liver by removing toxins from blood. To analyze the efficacy of MARS treatment, the outcomes of 113 ALF patients, treated with MARS between 2001 and 2007, were compared with a historical control group of 46 ALF patients treated without MARS between 1995 and 2001. Overall survival of transplanted patients was 94% in the MARS group and 77% in the control group (P=0.06). Without transplantation, survival was 66% and 40% (P=0.03), respectively. However, the etiological distribution of ALF differed significantly between the groups. In ALF patients with unknown etiology, groups were comparable at baseline; 91% and 69% of transplanted patients survived the MARS and control groups and the native liver recovered in 20% and 8% of the patients, respectively. Of the originally nonencephalopathic patients of unknown etiology, 36% underwent liver transplantation in the MARS group compared to 100% in the control group. Interpretation of the results was difficult in toxic etiology patients on account of differing baseline statuses. MARS treatment might partly explain the trend toward increased survival of ALF patients with unknown etiology.

Liver support devices

PURPOSE OF REVIEW

Liver support devices are used either as a bridge to liver transplantation or liver recovery in patients with acute or acute-on-chronic liver failure. The review analyzes the recent literature and asks if the current enthusiasm for these devices is justified.

RECENT FINDINGS

Many liver support devices exist and are discussed. Clinical data on artificial devices are rapidly emerging, especially on the molecular adsorbents recirculating system, and fractionated plasma separation and adsorption (Prometheus). While hepatic encephalopathy is improved by the molecular adsorbents recirculating system and probably Prometheus too, neither system has been shown to improve survival. Less clinical data exist for bioartificial support devices. These may use human hepatocytes, such as the extracorporeal liver assist device, although most devices use porcine hepatocytes, such as HepatAssist.

SUMMARY

Enthusiasm in liver support devices is justified as many nonrandomized studies have suggested some biochemical and clinical benefits. The results of several ongoing multicenter randomized controlled trials are anxiously awaited. Meanwhile, because mortality without liver transplantation remains high despite the use of liver support devices, these devices should only be used in the research setting or by experts proficient in their use and as a bridge to liver transplantation rather than liver recovery.

Bench-to-bedside review: current evidence for extracorporeal albumin dialysis systems in liver failure

Acute liver failure (ALF) and acute on chronic liver failure (AoCLF) carry a high mortality. The rationale for extracorporeal systems is to provide an environment facilitating recovery or a window of opportunity for liver transplantation. Recent technologies have used albumin as a scavenging molecule. Two different albumin dialysis systems have been developed using this principle: MARS (Molecular Adsorbent Recirculation System) and SPAD (Single-Pass Albumin Dialysis). A third system, Prometheus (Fractionated Plasma Separation and Adsorption), differs from the others in that the patient's albumin is separated across a membrane and then is run over adsorptive columns. Although several trials have been published (particularly with MARS), currently there is a lack of controlled studies with homogenous patient populations. Many studies have combined patients with ALF and AoCLF. Others have included patients with different etiologies. Although MARS and Prometheus have shown biochemical improvements in AoCLF and ALF, additional studies are required to show conclusive benefit in short- and long-term survival. The appropriate comparator is standard medical therapy rather than head-to-head comparisons of different forms of albumin dialysis.

Sorbent-based artificial liver devices: principles of operation, chemical effects and clinical results

Devices for support of patients with liver failure are of two types: bioartificial livers and artificial livers. Bioartificial livers include hepatocytes in bioreactors to provide both excretory and synthetic liver functions. Artificial livers use nonliving components to remove toxins of liver failure, supply nutrients and macromolecules. Current artificial liver devices use columns or suspensions of sorbents (including adsorbents and absorbents) to selectively remove toxins and regenerate dialysate, albumin-containing dialysate, plasma filtrate or plasma. This article reviews three artificial liver devices. Liver Dialysis uses a suspension of charcoal and cation exchangers to regenerate dialysate. MARS uses charcoal and an anion exchanger to regenerate dialysate with albumin. Prometheus uses neutral and anion exchange resins to regenerate a plasma filtrate containing albumin and small globulins. We review the operating principles, chemical effects, clinical effects and complications of use of each type of artificial liver. These devices clearly improve the clinical condition of patients with acute or acute-on-chronic liver failure. Further randomized outcome studies are necessary to prove clinical outcome benefit of the artificial liver support devices, and define what types of patients appear most amenable to therapy.

The model for end-stage liver disease comes of age

The care of patients who have chronic liver disease has evolved considerably since the Model for End-stage Liver Disease (MELD) was first described 6 years ago. This article traces the progress in liver allocation and clinical liver disease research that includes the MELD score and highlights the management of areas in which MELD and the principles underlying MELD enhance the clinician's ability to understand better the patient who has chronic liver disease.

Modern management of acute liver failure

Liver transplantation has revolutionized the management of acute or fulminant liver failure. Overall success rates of liver transplantation are satisfactory, although not as high as for elective transplantation. Although the bulk of liver transplants use standard whole grafts, interesting data are emerging on auxiliary liver grafts and donations from living donors. Liver transplantation is an integral part of management protocols complementing the sophisticated critical care protocols that have contributed significantly to the overall improved outcomes seen in acute liver failure. The potential for liver support devices to have an impact on the need for liver transplantation and outcomes after transplantation remains exciting.

Epidemiology of acute liver failure

Acute liver failure (ALF) is an uncommon disorder that leads to jaundice, coagulopathy, and multisystem organ failure. Its definition is based on the timing from onset of jaundice to encephalopathy. In 2005, ALF accounted for 6% of liver-related deaths and 7% of orthotopic liver transplants (OLT) in the United States. Several classification systems have been developed for ALF, with the King's College criteria most widely used for prediction of OLT. Specific diagnostic tests should be implemented to identify the cause of ALF, which will help to determine its treatment and prognosis. Viral hepatitis was previously reported to be the most common cause of ALF in the United States, but acetaminophen overdose and idiosyncratic drug reactions have emerged as the most frequent causes in recent studies. Malignancy is an uncommon cause of ALF, and thus imaging studies may not be useful in this setting, but liver biopsy may be beneficial in selected cases. An overall strategy for ALF should start with identifying the cause, assessing the prognosis, and early transfer to a transplantation center for suitable candidates. OLT has emerged as a life-saving procedure leading to marked improvement in survival rates. Improved surgical techniques, immunosuppression, and comprehensive care have led to an overall survival rate of approximately 65% with OLT. N-acetylcysteine is effective in ALF caused by acetaminophen overdose, with results strongly related to how soon it is given rather than the route of administration. Liver support systems show potential for the treatment of ALF, but their role needs validation in large multicenter randomized trials.