Effect of Prometheus liver assist system on systemic hemodynamics in patients with cirrhosis: A randomized controlled study

Safety and efficacy of Single-Pass Albumin Dialysis (SPAD), Prometheus, and Molecular Adsorbent Recycling System (MARS) liver haemodialysis vs. Standard Medical Therapy (SMT): meta-analysis and systematic review

Introduction

Because not all liver dysfunction patients are suitable for transplantations and there is a shortage of grafts, liver support therapies have gained interest. In this regard, extracorporeal albumin dialysis devices such as single-pass albumin dialysis (SPAD), Prometheus, and molecular adsorbent recycling system (MARS) have been valuable in supplementing standard medical therapy (SMT). However, the efficacy and safety of these devices is often questioned.Aim: We performed a systematic review to summarize the efficacy and safety of MARS, SPAD, and Prometheus as supportive treatments for liver dysfunction.

Material and methods

PubMed, Medline, Cochrane Library, Web of Science, and Google Scholar electronic databases were extensively searched for all randomized trials published in English. In addition, meta-analytic analyses were performed with Review Manager software, and Cochrane's risk of bias tool embedded in this software was used for bias assessment.

Results

Twelve trials including a total of 653 patients were eligible for inclusion. Subgroup analyses of data from these trials revealed that MARS and Prometheus were associated with significant removal of bilirubin (MD = -5.14 mg/dl; 95% CI: -7.26 - -3.02; p < 0.00001 and MD = -8.11 mg/dl; 95% CI: -12.40 - -3.82; p = 0.0002, respectively) but not bile acids and ammonia when compared to SMT. Furthermore, MARS was as effective as Prometheus and SPAD in the reduction of bilirubin (MD = 2.98 mg/dl; 95% CI: -4.26 - 10.22; p = 0.42 and MD = 0.67 mg/dl; 95% CI: -2.22 - 3.56; p = 0.65), bile acids (MD = -17.06 µmol/l; 95% CI: -64.33 - 30.20; p = 0.48 and MD = 16.21 µmol/l; 95% CI: -17.26 - 49.68; p = 0.34), and ammonia (MD = 26 µmol/l; 95% CI: -12.44 - 64.44; p = 0.18). In addition, MARS had a considerable effect in improving hepatic encephalopathy (HE) (RR = 1.54; 95% CI: 1.15-2.05; p = 0.004). However, neither MARS nor Prometheus had a mortality benefit compared to SMTRR (0.86; 95% CI: 0.71-1.03; p = 0.11 and RR = 0.87; 95% CI: 0.66-1.14; p = 0.31, respectively).

Conclusions

MARS, SPAD, and Prometheus, as liver support therapies, are equally effective in reducing albumin-bound and water-soluble substances. Moreover, MARS is associated with HE improvement. However, none of the therapies was associated with a significant reduction in mortality or adverse events.

Review article: Emerging and current management of acute-on-chronic liver failure

BACKGROUND

Acute-on-chronic liver failure (ACLF) is a clinically and pathophysiologically distinct condition from acutely decompensated cirrhosis and is characterised by systemic inflammation, extrahepatic organ failure, and high short-term mortality.

AIMS

To provide a narrative review of the diagnostic criteria, prognosis, epidemiology, and general management principles of ACLF. Four specific interventions that are explored in detail are intravenous albumin, extracorporeal liver assist devices, granulocyte-colony stimulating factor, and liver transplantation.

METHODS

We searched PubMed and Cochrane databases for articles published up to July 2023.

RESULTS

Approximately 35% of hospital inpatients with decompensated cirrhosis have ACLF. There is significant heterogeneity in the criteria used to diagnose ACLF; different definitions identify different phenotypes with varying mortality. Criteria established by the European Association for the Study of the Liver were developed in prospective patient cohorts and are, to-date, the most well validated internationally. Systemic haemodynamic instability, renal dysfunction, coagulopathy, neurological dysfunction, and respiratory failure are key considerations when managing ACLF in the intensive care unit. Apart from liver transplantation, there are no accepted evidence-based treatments for ACLF, but several different approaches are under investigation.

CONCLUSION

The recognition of ACLF as a distinct entity from acutely decompensated cirrhosis has allowed for better patient stratification in clinical settings, facilitating earlier engagement with the intensive care unit and liver transplantation teams. Research priorities over the next decade should focus on exploring novel treatment strategies with a particular focus on which, when, and how patients with ACLF should be treated.

Liver replacement therapy with extracorporeal blood purification techniques current knowledge and future directions

Clinically, it is highly challenging to promote recovery in patients with acute liver failure (ALF) and acute-on-chronic liver failure (ACLF). Despite recent advances in understanding the underlying mechanisms of ALF and ACLF, standard medical therapy remains the primary therapeutic approach. Liver transplantation (LT) is considered the last option, and in several cases, it is the only intervention that can be lifesaving. Unfortunately, this intervention is limited by organ donation shortage or exclusion criteria such that not all patients in need can receive a transplant. Another option is to restore impaired liver function with artificial extracorporeal blood purification systems. The first such systems were developed at the end of the 20^th century, providing solutions as bridging therapy, either for liver recovery or LT. They enhance the elimination of metabolites and substances that accumulate due to compromised liver function. In addition, they aid in clearance of molecules released during acute liver decompensation, which can initiate an excessive inflammatory response in these patients causing hepatic encephalopathy, multiple-organ failure, and other complications of liver failure. As compared to renal replacement therapies, we have been unsuccessful in using artificial extracorporeal blood purification systems to completely replace liver function despite the outstanding technological evolution of these systems. Extracting middle to high-molecular-weight and hydrophobic/protein-bound molecules remains extremely challenging. The majority of the currently available systems include a combination of methods that cleanse different ranges and types of molecules and toxins. Furthermore, conventional methods such as plasma exchange are being re-evaluated, and novel adsorption filters are increasingly being used for liver indications. These strategies are very promising for the treatment of liver failure. Nevertheless, the best method, system, or device has not been developed yet, and its probability of getting developed in the near future is also low. Furthermore, little is known about the effects of liver support systems on the overall and transplant-free survival of these patients, and further investigation using randomized controlled trials and meta-analyses is needed. This review presents the most popular extracorporeal blood purification techniques for liver replacement therapy. It focuses on general principles of their function, and on evidence regarding their effectiveness in detoxification and in supporting patients with ALF and ACLF. In addition, we have outlined the basic advantages and disadvantages of each system.

Bioartificial livers: a review of their design and manufacture

Acute liver failure (ALF) is a rapidly progressive disease with high morbidity and mortality rates. Liver transplantation and artificial liver support systems, such as artificial livers (ALs) and bioartificial livers (BALs), are the two major therapies for ALF. Compared to ALs, BALs are composed of functional hepatocytes that provide essential liver functions, including detoxification, metabolite synthesis, and biotransformation. Furthermore, BALs can potentially provide effective support as a form of bridging therapy to liver transplantation or spontaneous recovery for patients with ALF. In this review, we systematically discussed the currently available state-of-the-art designs and manufacturing processes for BAL support systems. Specifically, we classified the cell sources and bioreactors that are applied in BALs, highlighted the advanced technologies of hepatocyte culturing and bioreactor fabrication, and discussed the current challenges and future trends in developing next generation BALs for large scale clinical applications.

Bridging to Allotransplantation-Is Pig Liver Xenotransplantation the Best Option?

In the past 20 y, the number of patients in the United States who died while waiting for a human donor liver totaled >52 000. The median national wait time for patients with acute liver failure and the most urgent liver transplant listing was 7 d in 2018. The need for a clinical "bridge" to allotransplantation is clear. Current options for supporting patients with acute liver failure include artificial liver support devices, extracorporeal liver perfusion, and hepatocyte transplantation, all of which have shown mixed results with regard to survival benefit and are largely experimental. Progress in the transplantation of genetically engineered pig liver grafts in nonhuman primates has grown steadily, with survival of the pig graft extended to almost 1 mo in 2017. Further advances may justify consideration of a pig liver transplant as a clinical bridge to allotransplantation. We provide a brief history of pig liver xenotransplantation, summarize the most recent progress in pig-to-nonhuman primate liver transplantation models, and suggest criteria that may be considered for patient selection for a clinical trial of bridging by genetically engineered pig liver xenotransplantation to liver allotransplantation.

Acute kidney injury spectrum in patients with chronic liver disease: Where do we stand?

Acute kidney injury (AKI) is a common complication of liver cirrhosis and is of the utmost clinical and prognostic relevance. Patients with cirrhosis, especially decompensated cirrhosis, are more prone to develop AKI than those without cirrhosis. The hepatorenal syndrome type of AKI (HRS–AKI), a spectrum of disorders in prerenal chronic liver disease, and acute tubular necrosis (ATN) are the two most common causes of AKI in patients with chronic liver disease and cirrhosis. Differentiating these conditions is essential due to the differences in treatment. Prerenal AKI, a more benign disorder, responds well to plasma volume expansion, while ATN requires more specific renal support and is associated with substantial mortality. HRS–AKI is a facet of these two conditions, which are characterized by a dysregulation of the immune response. Recently, there has been progress in better defining this clinical entity, and studies have begun to address optimal care. The present review synopsizes the current diagnostic criteria, pathophysiology, and treatment modalities of HRS–AKI and as well as AKI in other chronic liver diseases (non-HRS–AKI) so that early recognition of HRS–AKI and the appropriate management can be established.

An evaluation of the usefulness of extracorporeal liver support techniques in patients with severe liver dysfunction

INTRODUCTION

The mortality rate in patients with severe liver dysfunction with no option of transplantation is unacceptably high. The main aim of this study was to evaluate the usefulness of applying extracorporeal liver support (ECLS) techniques in this group of patients.

MATERIAL AND METHODS

Data from hospital admissions of 101 patients with severe liver dysfunction who were admitted to the department of Anaesthesiology and intensive therapy between 2006 and 2015 were retrospectively analysed. The study group was divided into two subgroups. Standard Medical therapy (SMT) was a subgroup of patients receiving standard Medical therapy, and SMT + ECLS was a subgroup containing patients receiving standard medical therapy complemented by at least one extracorporeal liver support procedure.

RESULTS

Significantly lower intensive care unit (ICU) mortality and 30-day mortality rates were found in the SMT + ECLS subgroup (p = 0.0138 and p = 0.0238 respectively). No difference in 3-month mortality was identified between the two groups. In a multivariate model, independent risk factors for ICU mortality proved to be the SOFA score and prothrombin time. The highest discriminatory power for ICU mortality was demonstrated for the SOFA score, followed by APACHE II, SAPS II, MELD UNOS and GCS scores. For 30-day mortality, however, the best discriminatory power was shown for the SAPS II score, followed by SOFA, APACHE II, MELD UNOS and GCS scores.

CONCLUSIONS

Further studies are needed to assess the contribution of non-biological extracorporeal liver support procedures to a decrease in mortality rates in the population of patients with severe liver dysfunction.

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.

A comparison among three different apheretic techniques for treatment of hyperbilirubinemia

Liver failure is associated to high mortality due to the accumulation of protein-bound metabolites, such as bilirubin, not removed by conventional hemodialysis. Different methods can efficiently remove them, such as the molecular adsorbent recirculating system (MARS), plasma exchange (PEX), and bilirubin or plasma adsorption perfusion (PAP). No direct comparison exists between MARS, PEX and PAP, and current guidelines do not specify which method (and when) to use. We have retrospectively evaluated MARS, PEX and PAP in their effectiveness in lowering plasma bilirubin concentration, and their effects on liver and kidney function. A total of 98 patients have been recruited, which comprised 68 patients treated with PAP (177 sessions), 16 patients with PEX (41 sessions) and 11 patients with MARS (21 sessions). Bilirubin, creatinine, liver enzymes were analyzed before and after the first treatment with each technique. The three methods did not differ for bilirubin lowering efficiency, with MARS showing only slightly less effective reductions. Finally, the three techniques did not differ in the amount of change of cholinesterase, but a lower reduction in AST was found using PAP. Our retrospective observation is one of the largest case series of hepatic failure treated with bilirubin absorption. The choice of the technique cannot be based on the desired reduction in bilirubin concentration. Based on costs and duration of treatment, we suggest that PAP could be considered as a first-line approach. In case of kidney involvement, MARS remains a valuable option.

Randomized controlled trial comparing lactulose plus albumin versus lactulose alone for treatment of hepatic encephalopathy

BACKGROUND

Hepatic encephalopathy (HE) is associated with poor prognosis and treatment of HE is primarily directed at the reduction of the blood ammonia levels. The study evaluated the efficacy and safety of albumin plus lactulose versus lactulose alone for treatment of overt HE.

METHODS

In prospective randomized controlled trial, 120 patients with overt HE were randomized in two groups: group A lactulose plus albumin (n = 60) and group B lactulose alone (n = 60). Primary end point was complete reversal of HE, and secondary end points were mortality and hospital stay.

RESULTS

A total of 120 patients (mean age 40.4 ± 9.3 years) were included in this study. Thirty-six (30%) patients were in Child-Turcotte-Pugh (CTP) class B, and 84 (70%) were in CTP Class C. Mean CTP score was 9.8 ± 2.1, and model for end-stage liver disease score was 26.1 ± 5.3. Twenty seven (22.5%) had grade 2, 57 (47.5%) had grade 3, and 36 (30%) had grade 4 HE at the time of admission. Forty-five (75%) patients in group A compared with 32 (53.3%) patients in group B had complete reversal of HE (P = 0.03). Mortality was significantly lower in lactulose plus albumin group (11[18.3%]) versus lactulose alone (19 [31.6%], [P < 0.05]). There was significant decrease in levels of arterial ammonia, interleukin-6, interleukin-18, tumor necrosis factor-alpha, and endotoxins after treatment in both groups; however, the delta decrease was significantly higher in group A compared with group B. Hospital stay was shorter in group A.

CONCLUSIONS

Combination of lactulose plus albumin is more effective than lactulose alone in treatment of overt HE.

Current state of knowledge of hepatic encephalopathy (part IV): Management of Hepatic Encephalopathy by liver support systems

Hepatic Encephalopathy is a devastating complication of End-Stage Liver Disease. In its severe grades it requires extra intervention beyond the standard medical approaches. In this article were view the role of liver support systems in managing hepatic encephalopthy.

Albumin Dialysis for Liver Failure: A Systematic Review

Albumin dialysis is the best-studied extracorporeal nonbiologic liver support system as a bridge or destination therapy for patients with liver failure awaiting liver transplantation or recovery of liver function. We performed a systematic review to examine the efficacy and safety of 3 albumin dialysis systems (molecular adsorbent recirculating system [MARS], fractionated plasma separation, adsorption and hemodialysis [Prometheus system], and single-pass albumin dialysis) in randomized trials for supportive treatment of liver failure. PubMed, Ovid, EMBASE, Cochrane's Library, and ClinicalTrials.gov were searched. Two authors independently screened citations and extracted data on patient characteristics, quality of reports, efficacy, and safety end points. Ten trials (7 of MARS and 3 of Prometheus) were identified (620 patients). By meta-analysis, albumin dialysis achieved a net decrease in serum total bilirubin level relative to standard medical therapy of 8.0 mg/dL (95% confidence interval [CI], -10.6 to -5.4) but not in serum ammonia or bile acids. Albumin dialysis achieved an improvement in hepatic encephalopathy relative to standard medical therapy with a risk ratio of 1.55 (95% CI, 1.16-2.08) but had no effect survival with a risk ratio of 0.95 (95% CI, 0.84-1.07). Because of inconsistency in the reporting of adverse events, the safety analysis was limited but did not demonstrate major safety concerns. Use of albumin dialysis as supportive treatment for liver failure is successful at removing albumin-bound molecules, such as bilirubin and at improving hepatic encephalopathy. Additional experience is required to guide its optimal use and address safety concerns.

Liver depurative techniques: a single liver transplantation center experience

BACKGROUND

In a liver transplant (LT) center, treatments with Prometheus were evaluated. The main outcome considered was 1 and 6 months survival.

METHODS

During the study period, 74 patients underwent treatment with Prometheus; 64 were enrolled, with a mean age of 51 ± 13 years; 47 men underwent 212 treatments (mean, 3.02 per patient). The parameters evaluated were age, sex, laboratorial (liver enzymes, ammonia) and clinical (model for end-stage liver disease and Child-Turcotte-Pugh score) data.

RESULTS

Death was verified in 23 patients (35.9%) during the hospitalization period, 20 patients (31.3%) were submitted to liver transplantation, and 21 were discharged. LT was performed in 4 patients with acute liver failure (ALF, 23.7%), in 7 patients with acute on chronic liver failure (AoCLF, 43.7%), and in 6 patients with liver disease after LT (30%). Seven patients who underwent LT died (35%). In the multivariate analysis, older age (P = .015), higher international normalized ratio (INR) (P = .019), and acute liver failure (P = .039) were independently associated with an adverse 1-month clinical outcome. On the other hand, older age (P = .011) and acute kidney injury (P = .031) at presentation were both related to worse 6-month outcome. For patients with ALF and AoCLF we did not observe the same differences.

CONCLUSIONS

In this cohort, older age was the most important parameter defining 1- and 6-month survival, although higher INR and presence of ALF were important for 1-month survival and AKI for 6-month survival. No difference was observed between patients who underwent LT or did not have LT.

Role of human albumin in the management of complications of liver cirrhosis

Albumin is a negatively charged, relatively small protein synthesized by liver cells. Is the most abundant protein in extracellular fluid and accounts for about 70% of the plasma colloid osmotic pressure. Therefore it plays a crucial role in regulating fluid distribution in the body. In addition, albumin possesses functional domains with important non-oncotic properties, such as potent anti-oxydant and scavenging activities, binding of highly toxic reactive metal species and a great amount of endogenous and exogenous substances. We have recently learned that albumin in cirrhosis undergoes a number of post-transcriptional changes that greatly impair its non-oncotic properties. The overall assessment of these changes clearly shows that the relative abundance of the native form of albumin is significantly reduced in hospitalized patients with cirrhosis and that these abnormalities worsen in parallel with the increasing severity of the disease. Thus, it is time to abandon the concept of serum albumin concentration and refer to the effective albumin concentration, that is the native intact albumin. Given the pathophysiological context in which we use human albumin in patients with cirrhosis, who are characterized by peripheral vasodilation and a low-grade but sustained inflammatory state, the use of albumin in patients with cirrhosis should aim at enhancing effective hypovolemia and exploiting its antioxidant and scavenging activities. The indications for the use of albumin in cirrhosis that clearly emerge from evidence-based medicine are represented by conditions characterized by an acute aggravation of effective hypovolemia and inflammation, such as such post-paracentesis circulatory dysfunction, spontaneous bacterial peritonitis, and hepatorenal syndrome. Other indications to the use of albumin that still require further studies are represented by bacterial infections other than spontaneous bacterial peritonitis, hepatic encephalopathy and long-term treatment of ascites, which has been debated for the last half-century.

Molecular adsorbent recirculating system and bioartificial devices for liver failure

Acute liver failure and acute-on-chronic liver failure remain clinical problems with unacceptable morbidity and mortality. The development of extracorporeal liver support systems that replace the detoxification, synthetic, and regulatory functions of the native liver represent a long-sought potential solution, but all the devices currently available are still far from ideal. In general, artificial (cell-free) and bioartificial liver support devices have shown their ability to decrease some circulating toxins, to ameliorate hepatic encephalopathy and other intermediate variables, and to be relatively safe. Their effects on the survival of patients with ALF or ACLF, however, have not been conclusively shown.

The role of molecular adsorbent recirculating system dialysis for extracorporeal liver support in children

The majority of children with acute, acute-on-chronic, and progressive chronic liver failure require liver transplantation. Since organ availability is limited, extracorporeal liver support systems are increasingly applied to bridge the time until transplantation. At present, four different devices are available: the molecular adsorbent recirculating system (MARS), Prometheus dialysis, plasma exchange combined with hemodialysis (PE/HD), and single-pass albumin dialysis (SPAD). Randomized trials in adults have demonstrated efficient toxin removal, improved portal hypertension, hemodynamic stability, and improved hepatic encephalopathy compared with standard medical therapy. None of the liver support systems has yet been evaluated systematically in children. Knowledge of the specific indications and technical features of the different devices is essential if applied in children. MARS combines albumin dialysis with conventional hemodialysis and allows for efficient removal of water and protein-bound toxins without exogenous protein delivery and the associated infectious and allergic risks. It has successfully been applied in children with otherwise intractable cholestatic pruritus and with liver failure. The benefits, however, need to be balanced against the costs and the risk of volume and nitrogen overload if repeated plasma infusion is required. In cases of active bleeding, plasma exchange in combination with hemodialysis should be preferred.

Liver support systems: will they ever reach prime time?

Liver support systems aim to provide temporary support of liver function while maintaining extra-hepatic function in patients with liver failure. Important advances have been achieved in the design of artificial and bio-artificial devices, but the current systems are far from meeting the ideal. Artificial devices provide detoxification through different dialysis procedures, whereas bio-artificial devices add synthetic functions by incorporating a cellular component into the system. Overall, liver support systems have consistently shown beneficial effects on the pathophysiology of liver failure, especially in acute-on-chronic liver failure. However, these beneficial effects have not been translated into an improvement of survival. Our review discusses the current evidence, paying special attention to the clinical aspects of (bio)-artificial liver support devices.

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.

The end-organ impairment in liver cirrhosis: appointments for critical care

Liver cirrhosis (LC) can lead to a clinical state of liver failure, which can exacerbate through the course of the disease. New therapies aimed to control the diverse etiologies are now more effective, although the disease may result in advanced stages of liver failure, where liver transplantation (LT) remains the most effective treatment. The extended lifespan of these patients and the extended possibilities of liver support devices make their admission to an intensive care unit (ICU) more probable. In this paper the LC is approached from the point of view of the pathophysiological alterations present in LC patients previous to ICU admission, particularly cardiovascular, but also renal, coagulopathic, and encephalopathic. Infections and available liver detoxifications devices also deserve mentioning. We intend to contribute towards ICU physician readiness to the care for this particular type of patients, possibly in dedicated ICUs.

Modifying three-dimensional scaffolds from novel nanocomposite materials using dissolvable porogen particles for use in liver tissue engineering

Background:

Although hepatocytes have a remarkable regenerative power, the rapidity of acute liver failure makes liver transplantation the only definitive treatment. Attempts to incorporate engineered three-dimensional liver tissue in bioartificial liver devices or in implantable tissue constructs, to treat or bridge patients to self-recovery, were met with many challenges, amongst which is to find suitable polymeric matrices. We studied the feasibility of utilising nanocomposite polymers in three-dimensional scaffolds for hepatocytes.

Materials and methods:

Hepatocytes (HepG2) were seeded on a flat sheet and in three-dimensional scaffolds made of a nanocomposite polymer (Polyhedral Oligomeric Silsesquioxane [POSS]-modified polycaprolactone urea urethane) alone as well as with porogen particles, i.e. glucose, sodium bicarbonate and sodium chloride. The scaffold architecture, cell attachment and morphology were studied with scanning electron microscopy, and we assessed cell viability and functionality.

Results:

Cell attachment to the scaffolds was demonstrated. The scaffold made with glucose particles as porogen showed a narrower range of pore size with higher porosity and better inter-pore communications and seemed to encourage near normal cell morphology. There was a steady increase of albumin secretion throughout the experiment while the control (monolayer cell culture) showed a steep decrease after day 7. At the end of the experiment, there was no significant difference in viability and functionality between the scaffolds and the control.

Conclusion:

In this initial study, porogen particles were used to modify the scaffolds produced from the novel polymer. Although there was no significance against the control in functionality and viability, the demonstrable attachment on scanning electron microscopy suggest potential roles for this polymer and in particular for scaffolds made with glucose particles in liver tissue engineering.

Multicenter study of plasma diafiltration in patients with acute liver failure

Plasma diafiltration (PDF) is a blood purification therapy in which simple plasma exchange (PE) is performed using a selective membrane plasma separator while the dialysate flows outside the hollow fibers. A prospective, multicenter study was undertaken to evaluate the changes in bilirubin, IL-18, and cystatin C, as well as the 28-day and 90-day survival rates, with the use of PDF according to the level of severity as measured by the Model for End-Stage Liver Disease (MELD) score. Twenty-one patients with liver failure were studied: 10 patients had fulminant hepatitis and PDF therapies were performed 28 times; 11 had acute liver failure with the therapy performed 96 times. Levels of total bilirubin, IL-18, and cystatin C decreased significantly after treatment. The 28-day survival rate was 70.0% and that at 90 days was 16.7%. According to the severity of the MELD score, each of the results compared well with the use of Molecular Adsorbent Recirculating System or Prometheus therapy. In conclusion, PDF appears to be one of the most useful blood purification therapies for use in cases of acute liver failure in terms of medical economics and the removal of water-soluble and albumin-bound toxins.

Comparison of Molecular Adsorbents Recirculating System (MARS) dialysis with combined plasma exchange and haemodialysis in children with acute liver failure

BACKGROUND

Molecular Adsorbents Recirculating System (MARS) is an extracorporeal liver support system eliminating albumin-bound and water-soluble substances. While it is increasingly applied in patients with acute liver failure (ALF), no comparison with standard dialysis methods has yet been performed.

METHODS

This is an analysis of ten children (0.1-18 years) with ALF, who underwent a total of 22 MARS sessions. Standard adult MARS sets were used in seven (23.5-72 kg) and MARS Mini in three children (2.8-13 kg). In eight children, MARS was alternated with combined plasma exchange (PE) and haemodialysis (HD) treatments. Mean treatment duration was 7.2 (6-10) h for MARS and 5.7 (4.5-6.6) h for PE/HD.

RESULTS

Standard MARS treatment only slightly decreased serum bilirubin (16.3 ± 6.5-13.8 ± 5.9 mg/dL) and ammonia (113 ± 62-99 ± 68 μmol/L) and international normalized ratio (INR) tended to increase (1.5 ± 0.3 and 2 ± 1.1). Mini-MARS did not reduce serum bilirubin (19.7 ± 3-20.5 ± 3.2 mg/dL), ammonia slightly decreased (70 ± 24-56 ± 9 μmol/L) and INR increased (2.5 ± 0.7-2.9 ± 1.1, all P = n.s.). In contrast, PE/HD reduced serum bilirubin (23 ± 8.4-14.7 ± 7 mg/dL), ammonia (120 ± 60-70 ± 40 μmol/L) and INR (2.4 ± 0.8-1.4 ± 0.1, all P < 0.05). Intraindividual comparison showed a slight increase in bilirubin by 2 ± 22% with MARS and a reduction by 37 ± 11% with PE/HD (P < 0.001 versus MARS) and a decrease in ammonia of 18 ± 27 and 39 ± 23% (P < 0.05). INR increased during MARS by 26 ± 41% and decreased with PE/HD by 37 ± 20% (P < 0.01). All treatment sessions were well tolerated. Five children died, including the three children treated with Mini-MARS.

CONCLUSION

Our experience suggests superior efficacy of combined PE/HD as compared to intermittent MARS therapy for treating ALF.

Systematic review and meta-analysis of survival following extracorporeal liver support

Background

Extracorporeal liver support (ELS) systems offer the potential to prolong survival in acute and acute-on-chronic liver failure. However, the literature has been unclear on their specific role and influence on mortality. This meta-analysis aimed to test the hypothesis that ELS improves survival in acute and acute-on-chronic liver failure.

Methods

Clinical trials citing MeSH terms ‘liver failure’ and ‘liver, artificial’ were identified by searching MEDLINE, Embase and the Cochrane registry of randomized controlled trials (RCTs) between January 1995 and January 2010. Only RCTs comparing ELS with standard medical therapy in acute or acute-on-chronic liver failure were included. A predefined data collection pro forma was used and study quality assessed according to Consolidated Standards of Reporting Trials (CONSORT) criteria. Risk ratio was used as the effect size measure according to a random-effects model.

Results

The search strategy revealed 74 clinical studies including 17 RCTs, five case–control studies and 52 cohort studies. Eight RCTs were suitable for inclusion, three addressing acute liver failure (198 participants) and five acute-on-chronic liver failure (157 participants). The mean CONSORT score was 14 (range 11–20). Overall ELS therapy significantly improved survival in acute liver failure (risk ratio 0·70; P = 0·05). The number needed to treat to prevent one death in acute liver failure was eight. No significant survival benefit was demonstrated in acute-on-chronic liver failure (risk ratio 0·87; P = 0·37).

Conclusion

ELS systems appear to improve survival in acute liver failure. There is, however, no evidence that they improve survival in acute-on-chronic liver failure.

The treatment of acute liver failure with fractionated plasma separation and adsorption system: Experience in 85 applications

INTRODUCTION

Artificial liver support systems represent a potential useful option for the treatment of liver failure. The outcomes of patients treated with the fractionated plasma separation and adsorption (FPSA) system are presented.

PATIENTS AND METHODS

FPSA was performed 85 times for 27 patients (median 3 treatments/patient) with liver failure [85.2% acute liver failure (ALF) and 14.8% acute-on-chronic liver failure] using the Prometheus 4008H (Fresenius Medical Care) unit. Citrate was used for anticoagulation. A variety of clinical and biochemical parameters were assessed. Comparisons between pretreatment and post-treatment data were performed using paired t-test.

RESULTS

The 85 sessions had a mean duration of 6 h. There were significant decreases in total bilirubin (13.18 +/- 9.46 mg/dL vs. 9.76 +/- 7.05 mg/dL; P < 0.0001), ammonia (167.6 +/- 75 mg/dL vs. 120 +/- 43.8 mg/dL; P < 0.0001), blood urea nitrogen (BUN; 12.55 +/- 13.03 mg/dL vs. 8.18 +/- 8.15 mg/dL; P < 0.0001), creatinine (0.54 +/- 0.47 mg/dL vs. 0.46 +/- 0.37 mg/dL; P = 0.0022) levels, and in pH (7.48 +/- 0.05 vs. 7.44 +/- 0.08; P = 0.0045). Four patients (14.8%) received liver transplantation after the treatments; in nine patients, transplantation was not necessary anymore (33%); the remaining 14 patients did not receive a transplantation because they were either not appropriate candidates or no organ was available. Overall survival was 48.1% (4 transplanted and 9 treated patients). No hematological complications related to FPSA were observed.

CONCLUSIONS

FPSA system is a safe and effective detoxification method for patients with liver dysfunction, including ALF. The system is useful as a symptomatic treatment before liver transplantation; in up to 1/3 of the cases, it can even be used as a sole method of treatment.

Renal and circulatory dysfunction in cirrhosis: current management and future perspectives

Chronic liver diseases are amongst the top leading causes of death in Europe as well as in other areas of the world. Chronic liver diseases are characterized by unrelenting progression of liver inflammation and fibrosis over a prolonged period of time, usually more than 20 years, which may eventually lead to cirrhosis. Advanced cirrhosis leads to a complex syndrome of chronic liver failure which involves many different organs besides the liver, including the brain, heart and systemic circulation, adrenal glands, lungs, and kidneys. The high morbidity and mortality secondary to chronic liver failure is due to complications related to the dysfunction of these organs, either alone or, more frequently, in combination. Understanding the mechanisms leading to organ dysfunction is crucial to the development of strategies for treatment and prevention of complications of cirrhosis. This article reviews our current knowledge, as well as future perspectives, on the management of circulatory and renal dysfunction in chronic liver failure.

[Evaluation of extracorporeal liver support systems in the treatment of liver failure. A systematic review]

OBJECTIVE

To evaluate the safety and efficacy of the MARS and Prometheus extracorporeal liver support systems in the treatment of liver failure.

DESIGN

We performed a systematic review of the literature from January 1999 to June 2009 in the Medline, Embase, HTA, DARE, NHSEED, Cochrane Library Plus, Clinical Trials Registry and HSRPROJ databases. Study selection was based on a series of previously established inclusion criteria related to the study design, population, type of intervention, language, and outcome measures.

PATIENTS AND INTERVENTIONS

Patients with acute liver failure or acute exacerbations of chronic liver failure treated with the MARS or Prometheus systems.

OUTCOME MEASURES

Data on safety, long-term survival, clinical effects and biochemical and hemodynamic variables.

RESULTS

We selected 22 studies evaluating the safety and efficacy of the MARS and Prometheus systems. Adequate evaluation of these techniques was hampered by the heterogeneity of the studies and their methodological limitations.

CONCLUSIONS

Extracorporeal liver support systems are able to purify both hydrosoluble and protein-bound substances. However, current data show that only the MARS system reduces mortality in acute liver failure and in acute exacerbations of chronic liver failure, although this reduction is non-significant. These techniques can be considered safe, with adverse effects similar to those of the control group. Their main indication is severe liver failure, for short periods while the liver recovers or a liver transplant becomes available.

Bioartificial liver support systems

A variety of bioartificial liver support systems were developed to replace some of the liver's function in case of liver failure. Those systems, in contrast to purely artificial systems, incorporate metabolically active cells to contribute synthetic and regulatory functions as well as detoxification. The selection of the ideal cell source and the design of more sophisticated bioreactors are the main issues in this field of research. Several systems were already introduced into clinical studies to prove their safety. This review briefly introduces a cross-section of experimental and clinically applied systems and tries to give an overview on the problems and limitations of bioartificial liver support.

Hemodynamic effects of albumin dialysis in patients with liver failure: for better or for worse?

Liver failure, irrespective of is cause, is frequently associated with multi-organ dysfunction, including hemodynamic instability, and renal and cerebral insufficiency. As a result of the combined impact of these complications, liver failure carries an exceptionally high risk of mortality. A central role in the etiopathogenesis of different end-organ manifestations, as well as in the aggravation of the underlying liver failure, has been attributed to the hyperdynamic (hypotensive) state, which is characterized by a reduced systemic vascular resistance and mean arterial pressure, as well as an increased cardiac index, heart rate, and total plasma volume. Since the accumulation of toxins due to the decreased detoxification capacity by the failing liver is considered vital herein, the emergence of extracorporeal liver support has provided a rational basis for the potential reversal of these phenomena. The present article critically reviews data with regard to the hemodynamic effects of artificial liver support in the context of liver failure. Although these are scarce for acute liver failure, several uncontrolled series and small randomized trials have clearly documented that artificial liver support is able to improve both portal hypertension and the associated systemic circulatory dysfunction in patients with acute-on-chronic liver failure. The molecular basis for these effects have been related to temporary changes and/or elimination in endogenous vasoactive substances, improved albumin binding capacity, or restoration of oxidative stress-mediated damage to albumin.

[Acute on chronic liver failure]

Acute-on-Chronic Liver Failure (ACLF) is a recently introduced term defined as severe acute deterioration of an established liver disease. This entity usually develops after an acute insult. The main clinical manifestations are hepatorenal syndrome, hepatic encephalopathy and organ failure, with a high risk of death in the short term. The true incidence of ACLF remains difficult to determine due to confusions surrounding the definition of this entity, but seems to be 40% at 5 years in patients with advanced cirrhosis, which translates into 4,000 cases in Europe within this time span. The treatment of choice is liver transplantation. However, due to the shortage of suitable organs and morbidity and mortality in these patients, other options must be used.

What clinical alternatives to whole liver transplantation? Current status of artificial devices and hepatocyte transplantation

Shortage of organ donors limits the number of possible liver transplantations. Alternative therapies for treatment of liver failure are currently being developed: (i) extracorporeal artificial liver devices; (ii) bioartificial liver devices using hepatocytes; and (iii) hepatocyte transplantation. The objective of these strategies is to bridge patients with liver failure until a suitable liver allograft is obtained for transplantation or the patient's own liver regenerates sufficiently to resume normal function. In this review, we discuss these strategies and summarize the current status of clinical experience.