Review of methods to remove protein-bound substances in liver failure

Bilirubin Removal by Polymeric Adsorbents for Hyperbilirubinemia Therapy

Hyperbilirubinemia, presenting as jaundice, is a life-threatening critical illness in newborn babies and acute severe hepatic failure patients. Over the past few decades, extracorporeal hemoadsorption by adsorbent therapy has been widely applied in the treatment of hyperbilirubinemia. The capability of hemoadsorption depends on the adsorbents. Most of the clinically used bilirubin adsorbents are made up of styrene/divinylbenzene copolymer and quaternary ammonium salt, which usually have poor biocompatibility and weak mechanical strength. To overcome the drawbacks of commercial polymer adsorbents, advanced synthetic and natural polymers with/without nanomaterials have been designed, and novel adsorbent fabrication technologies have also been developed. In this review, the adsorption mechanism of bilirubin adsorbents has been summarized, which is the basic criterion in adsorbent development. Furthermore, the preparation method, adsorption mechanism, relative merits and practicability of the emerging bilirubin adsorbents have been evaluated. Based on the existing studies, this work highlights the future direction of the efforts on how to design and develop bilirubin adsorbents with good overall clinical performance. Perhaps this study can change traditional perspectives and propose new strategies for bilirubin clearance from the aspects of pathogenic mechanisms, metabolic pathways, and material-based innovation.

The Artificial-Liver Blood-Purification System Can Effectively Improve Hypercytokinemia for COVID-19

Since the December 2019 outbreak of coronavirus disease 2019 (COVID-19) in Wuhan, the infection has spread locally and globally resulting in a pandemic. As the numbers of confirmed diagnoses and deaths continue to rise, COVID-19 has become the focus of international public health. COVID-19 is highly contagious, and there is no effective treatment yet. New treatment strategies are urgently needed to improve the treatment success rate of severe and critically ill patients. Increasing evidence has shown that a cytokine storm plays an important role in the progression of COVID-19. The artificial-liver blood-purification system (ALS) is expected to improve the outcome of the cytokine storm. In the present study, the levels of cytokines were detected in 12 COVID-19 patients pre- and post-ALS with promising results. The present study shows promising evidence that ALS can block the cytokine storm, rapidly remove the inflammatory mediators, and hopefully, suppress the progression of the disease, thereby providing a new strategy for the clinical treatment of COVID-19.

Hemocompatible hemoadsorbent for effective removal of protein-bound toxin in serum

Resin hemoperfusion is a life-saving treatment for drug intoxication or hepatic failure of patients. However, current resin adsorbents exhibit a limited hemocompatibility or low adsorption efficiency, representing a major roadblock to successful clinical applications. In this work, we developed a hemocompatible and effective hemoadsorbent based on polystyrene resin (H103) microparticles encapsulated in anti-biofouling zwitterionic poly(carboxybetaine) (PCB) hydrogels. Apart from a strong mechanical stability, this PCB-based adsorbent (PCB-H103) exhibited excellent hemocompatibility (hemolysis ratio was ∼0.64%), which was attributed to the anti-biofouling property of PCB hydrogel. In addition, it can efficiently adsorb both small and middle molecular weight molecules in phosphate-buffered saline, and the efficiencies were significantly higher than poly(ethylene glycol) methacrylate-based and poly(2-hydroxyethyl methacrylate)-based adsorbent counterparts, indicating the favorable permeability of PCB hydrogel coating. More importantly, PCB-H103 could effectively remove protein-bound toxins including phenol red and bilirubin in bovine serum albumin solution or even in 100% fetal bovine serum (FBS). In 100% FBS, the adsorption capacity of PCB-H103 towards bilirubin was 8.3 times higher than that of pristine clinical-scale resin beads. Findings in this work may provide a new strategy for the development of modern resin hemoperfusion technology.

Plasma exchange-centered artificial liver support system in hepatitis B virus-related acute-on-chronic liver failure: a nationwide prospective multicenter study in China

BACKGROUND

Plasma exchange (PE)-centered artificial liver support system reduced the high mortality rate of hepatitis B virus (HBV)-related acute-on-chronic liver failure (ACLF). But the data were diverse in different medical centers. The present prospective nationwide study was to evaluate the effects of PE on patients with HBV-ACLF at different stages.

METHODS

From December 2009 to December 2011, we evaluated 250 patients at different stages of HBV-ACLF from 10 major medical centers in China. All the laboratory parameters were collected at admission, before and after PE.

RESULTS

Among the 250 patients who underwent 661 rounds of PE, one-month survival rate was 61.6%; 141 (56.4%) showed improvement after PE. Variables such as age (P=0.000), levels of total bilirubin (TB, P=0.000), direct bilirubin (P=0.000), total triglycerides (P=0.000), low-density lipoprotein (P=0.022), Na+ (P=0.014), Cl- (P=0.038), creatinine (Cr, P=0.007), fibrinogen (P=0.000), prothrombin time (PT, P=0.000), white blood cell (P=0.000), platelet (P=0.003) and MELD (P=0.000) were significantly related to prognosis. Multivariate logistic regression analysis showed that age, disease stage, TB, Cr and PT levels were independent risk factors of mortality among HBV-ACLF patients.

CONCLUSIONS

PE can improve the clinical outcome of patients with HBV-ACLF. Levels of TB, Cr and PT, age and disease stage help to predict prognosis.

Evaluation of plasma exchange and continuous veno-venous hemofiltration for the treatment of severe avian influenza A (H7N9): a cohort study

Avian influenza A (H7N9) is a severe disease with high mortality. Hypercytokinemia is thought to play an important role in the pathogenesis. This study was to investigate the efficiency of plasma exchange (PE) + continuous veno-venous hemofiltration (CVVH) on the removal of inflammatory mediators and their benefits in the management of fluid overload and metabolic disturbance. In total, 40 H7N9-infected patients were admitted to our hospital. Sixteen critically ill H7N9-infected patients received combination of PE and CVVH. Data from these 16 patients were collected and analyzed. The effects of PE + CVVH on plasma cytokine/chemokine levels and clinical outcomes were examined. H7N9-infected patients had increased plasma levels compared to healthy controls. After 3 h of PE + CVVH treatment, the cytokine/chemokine levels descended remarkably to lower levels and were maintained thereafter. PE + CVVH also benefited the management of fluid, cardiovascular dysfunction and metabolic disturbance. Of the 16 critically ill patients who received PE + CVVH, 10 patients survived. PE + CVVH decreased the plasma cytokine/chemokine levels significantly. PE + CVVH were also beneficial to the management of severe avian influenza A (H7N9).

A promising hepatocyte-like cell line, CCL-13, exhibits good liver function both in vitro and in an acute liver failure model

BACKGROUND

A great many patients awaiting liver transplantation die because of the shortage of donor livers. To resolve the problem, liver support systems like bioartificial livers (BALs) have become subjects of active investigation. However, the problem with BALs is that it is difficult to find a source of healthy hepatic cells with good liver function. This study explored the possibility of employing Chang liver cells (ATCC CCL-13), a human hepatoma cell line as a source for liver support.

METHODS

To evaluate the function of Chang liver cells in vitro, hepatocyte markers were measured by Western blotting and laser confocal microscopy. The gene expression of hepatic markers was examined by reverse transcriptase polymerase chain reaction (RT-PCR). After acute liver failure (ALF) was established by 90% partial hepatectomy, Chang liver cells were intrasplenically transplanted for treatment.

RESULTS

In vitro, Western blotting and laser confocal microscopy showed conspicuous expression of liver function markers, such as albumin, uridine diphosphate glucuronosyltransferase, and cytochrome P450 3A4 by Chang liver cells. RT-PCR revealed expression of related genes at the mRNA level. The survival of rats receiving transplanted Chang liver cells reached 40% versus 0% among the controls (P < .01). Liver function of rats receiving transplanted Chang liver cells was improved at 24 hours after ALF, as evidenced by decreased levels of alanine transaminase, aspartate aminotransferase, bilirubin, and alkaline phosphate.

CONCLUSIONS

Chang liver cells, which express liver function markers and exert obvious liver-protective effects in ALF can serve in liver support systems.

Macroporous Composite Cryogels with Embedded Polystyrene Divinylbenzene Microparticles for the Adsorption of Toxic Metabolites from Blood

Composite monolithic adsorbents were prepared by the incorporation of neutral polystyrene divinylbenzene (PS-DVB) microparticles into macroporous polymer structures produced by cryogelation of agarose or poly(vinyl alcohol). The composite materials exhibited excellent flow-through properties. Scanning electron microscopy of the composite cryogels revealed that the microparticles were covered by thin films of poly(vinyl alcohol) or agarose and thus were withheld in the monolith structure. Plain PS-DVB microparticles showed efficient adsorption of albumin-bound toxins related to liver failure (bilirubin and cholic acid) and of cytokines (tumor necrosis factor-alpha and interleukin-6). The rates of adsorption and the amount of adsorbed factors were lower for the embedded microparticles as compared to the parent PS-DVB microparticles, indicating the importance of the accessibility of the adsorbent pores. Still, the macroporous composite materials showed efficient adsorption of albumin-bound toxins related to liver failure as well as efficient binding of cytokines, combined with good blood compatibility. Thus, the incorporation of microparticles into macroporous polymer structures may provide an option for the development of adsorption modules for extracorporeal blood purification.

Effect of anticoagulation with citrate versus heparin on the adsorption of coagulation factors to blood purification resins with different charge

In liver failure, hydrophobic toxins accumulate in the blood circulation. To support hepatic function, extracorporeal blood purification systems have been developed, in which both cationic and neutral adsorbents are used to remove albumin-bound metabolites from blood. An issue of these systems is the additional removal of coagulation factors containing negatively charged γ-carboxyglutamate (Gla) domains, which, in physiological conditions, are shielded by calcium ions. We hypothesized that complexation of calcium ions by citrate leads to exposure of negative Gla domains, resulting in their binding to the positively charged adsorbents. The data presented here confirm that the binding of coagulation factors containing Gla domains to positively charged polymers is enhanced in the presence of citrate as compared to heparin. This effect increased with increasing charge density of the polymer and has important implications for the clinical application of positively charged polymers.

Activation-dependent adsorption of cytokines and toxins related to liver failure to carbon beads

In the course of severe pathological conditions, such as acute liver failure and sepsis, toxic metabolites and mediators of inflammation are released into the patient's circulation. One option for the supportive treatment of these conditions is plasmapheresis, in which plasma, after being separated from the cellular components of the blood, is cleansed by adsorption of harmful molecules on polymers or activated carbon. In this work, the adsorption characteristics of activated carbon beads with levels of activation ranging from 0 to 86% were assessed for both hydrophobic compounds accumulating in liver failure (bilirubin, cholic acid, phenol and tryptophan) and cytokines (tumor necrosis factor α and interleukin-6). Progressive activation resulted in significant gradual reduction of both bulk density and mean particle size, in an increase in the specific surface area, and to changes in pore size distribution with progressive broadening of micropores. These structural changes went hand in hand with enhanced adsorption of small adsorbates, such as IL-6 and cholic acid and, to a lesser extent, also of large molecules, such as TNF-α.

Adsorbents with high selectivity for uremic middle molecular peptides containing the Asp-Phe-Leu-Ala-Glu sequence

Asp-Phe-Leu-Ala-Glu (DE5) is a frequent sequence of many toxic middle molecular peptides that accumulate in uremic patients. To eliminate these peptides by hemoperfusion, three adsorbents (CP1-Zn(2+), CP2-Zn(2+), and CP3-Zn(2+)) were designed on the basis of coordination and hydrophobic interactions. Adsorption experiments indicated that CP2-Zn(2+) had the highest affinity for DE5 among these three adsorbents. Also, the adsorption capacity of CP2-Zn(2+) in DE5 and DE5-containing peptides was about 2-6 times higher than that of peptides without the DE5 sequence. Linear polymers bearing the same functional groups of the adsorbents were used as models to study the adsorption mechanism via isothermal titration calorimetry (ITC) and computer-aided analyses. The results indicated that coordination and hydrophobic interactions played the most important roles in their affinity. When two carboxyl moieties on Asp and Glu residues coordinated to CP2-Zn(2+), the hydrophobic interaction took place by the aggregation of the hydrophobic amino acid residues with phenyl group on CP2-Zn(2+). The optimal collaboration of these interactions led to the tight binding and selective adsorption of DE5-containing peptides onto CP2-Zn(2+). These results may provide new insight into the design of affinity adsorbents for peptides containing DE5-like sequences.

Role of artificial liver support in hepatic encephalopathy

Hepatic encephalopathy (HE) refers to the reversible neuropsychiatric disorders observed in acute liver failure and as a complication of cirrhosis and/or portal hypertension. This review aims to describe the pathophysiology of HE, the rationale for the use of artificial liver support in the treatment of HE, the different concepts of artificial liver support and the results obtained. Ammonia has been considered central to its pathogenesis but recently an important role for its interaction with inflammatory responses and auto-regulation of cerebral hemodynamics has been suggested. Artificial liver support might be able to decrease ammonia and modulate inflammatory mediators and cerebral hemodynamics. Bioartificial liver support systems use hepatocytes in an extracorporeal device connected to the patient's circulation. Artificial liver support is intended to remove protein-bound toxins and water-soluble toxins without providing synthetic function. Both systems improve clinical and biochemical parameters and can be applied safely to patients. Clinical studies have shown that artificial liver support, especially albumin dialysis, is able to improve HE in acute and acute-on-chronic liver failure. Further studies are required to better understand the mechanism, however, artificial liver support can be added to the therapeutic bundle in treating HE.

[Safety and efficacy of the MARS therapy applied by continuous renal replacement therapy (CRRT) monitors]

OBJECTIVE

Analyze the utility and safety of MARS therapy applied with the CRRT monitor.

DESIGN

Prospective study of cohorts.

SCOPE

Polyvalent ICU in tertiary university hospital with hepatic transplantation program.

PATIENTS

Thirty one patients: 9 (22.6%) with acute liver failure (ALF) (1 hepatic surgery, 1 primary graft failure, 7 other causes) and 22 (71%) with acute-on-chronic failure (AoCLF).

INTERVENTIONS

For the treatment, the patients with ALF are maintained in the ICU but those with AoCLF are admitted for the performance of the different sessions, that are programmed for a duration of at least 15 hours in AoCLF and in ALF are maintained continuously, changing the circuit every 24 hours.

VARIABLES OF INTEREST

Metabolic control and complications registered in 75 sessions on 31 patients.

RESULTS

Urea decrease was 33.5 (29-38%), creatinine 36 (31-41%), total bilirubin 29 (25-33%) and direct bilirubin 34 (30-38%). Clearance was slower, but sustained, after the first 4 hours of each session both for urea (p<0.001) as well as for bilirubin (p<0.05). The hemodynamic parameters improved and the hematological ones were not altered. We detected decrease in platelets (131 to 120x109/L, p<0.01). In 95 of the sessions in which heparin was used and in 6% where epoprostenol was used, we observed mild bleeding. We cultured albumin of the circuit at the end of the session in 50 occasions and only obtained growth in 3 cases (6%) (2 Staphylococcus epidermidis, 1 S. haemolyticus) without signs of contamination in the patients.

CONCLUSIONS

The MARS system applied by CRRT monitors provide adequate bilirubin clearance percentages and is safe, even in serious patients. Prolongation of the duration of the sessions was not accompanied by an increase in the risk of infection secondary to the albumin contamination.

Characterization of pro-apoptotic effect of liver failure plasma on primary human hepatocytes and its modulation by molecular adsorbent recirculation system therapy

Plasma from patients with liver failure may contain toxic molecules that cause hepatocyte apoptosis and worsen liver disease, suggesting that removal of pro-apoptotic factors is an appropriate therapeutic strategy. We investigated the apoptosis of human hepatocytes induced by plasma from patients with both acute and acute-on-chronic liver disease, and the effect of molecular adsorbent dialysis (molecular adsorbent recirculation system [MARS] dialysis) on this. Apoptotic effects of acute and acute-on-chronic liver failure plasmas from 46 patients were assessed on cultured primary human hepatocytes using terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) labeling and caspase 3 activation. In 11 patients undergoing MARS dialysis, the pro-apoptotic effect of their plasma was analyzed before and after therapy. Acute liver failure plasma induced more apoptosis than normal plasma (within 4-6 h of culture, a 2.5-fold increase by TUNEL labeling, 1.8-fold by caspase 3 activation), via a pathway involving caspase 8, suggesting involvement of the death-receptor pathway. However, not all acute liver failure plasmas were significantly more pro-apoptotic than normal plasma. Plasma from patients with acutely decompensated chronic liver disease induced apoptosis at the same rate as normal plasma. MARS dialysis improved biochemical parameters indicating effective removal of albumin-bound molecules, but the apoptotic effects of the plasma were unchanged. Thus, plasma of patients with acute liver failure, compared to normal plasma, induced increased apoptosis of primary human hepatocytes by a caspase-8- and caspase-3-dependent pathway. The apoptosis induced in the presence of liver failure plasma was not reduced by MARS dialysis.

Albumin-binding function is reduced in patients with decompensated cirrhosis and correlates inversely with severity of liver disease assessed by model for end-stage liver disease

BACKGROUND

Human serum albumin has multiple functions, the most important being maintaining colloid osmotic pressure, ligand binding and transport. In liver failure, an impaired binding of endogenous substances and drugs can be observed. The aim of this study was to investigate the relationship between the severity of liver disease and an impaired albumin binding.

METHODS

In 44 patients with decompensated liver cirrhosis, Child-Turcotte-Pugh and model for end-stage liver disease scores were assessed and the site II-specific albumin-binding function (albumin-binding capacity) was characterized. Briefly, the unbound amount of diazepam site ligand Dansylsarcosine in a sample was determined and compared with the unbound amount in a reference albumin solution (=100%).

RESULTS

Thirty-two out of 44 of the patients presented with Child-Turcotte-Pugh class C, the median Child-Turcotte-Pugh score was 10 [6-13 (min-max)], median model for end-stage liver disease score was 21 (8-40) and the median albumin-binding capacity was 63 (24-91)% compared with healthy controls 98 (95-106)% (P<0.001). Albumin-binding capacity was found to be strongly correlated to model for end-stage liver disease (r=0.783; P<0.001).

CONCLUSIONS

An impaired albumin-binding function of a site II-specific marker in decompensated liver cirrhosis was found to be correlated to the severity of the liver disease.

A novel plasma filtration therapy for hepatic failure: preclinical studies

There is a need to develop artificial means of liver replacement and/or assistance with the aim of either supporting patients with borderline functional liver cell mass until their liver regenerates, or until a donor liver becomes available for transplantation. Selective plasma filtration is a novel approach to blood purification therapy designed to reduce the level of circulating toxins of hepatic and renal failure, mediators of inflammation and inhibitors of hepatic regeneration. The results of preclinical studies indicate that treatment of pigs with experimentally-induced fulminant hepatic failure is safe and effective in extending survival time and arresting brain swelling. In addition, the amount of ammonia, aromatic amino acids, IL6, TNFalpha and C3a removed during the 6-h treatment in the present study was higher by 34% to 175% than the total plasma content of those substances at the start of therapy.

Effects of artificial liver support system on patients with acute or chronic liver failure

AIMS

Acute on chronic liver failure (AoCLF) is associated with a high mortality rate. Artificial liver support system (ALSS) is useful to bridge patients with liver failure to liver transplantation or to regenerate their own livers. The aims of this prospective study were to investigate the effects of ALSS on clinical manifestations, liver function, and 30-day survival to probe the factors related to mortality in patients with AoCLF.

METHODS

In this study, 338 enrolled patients with AoCLF who received ALSS treatment for 1 to 8 sessions, were compared with 312 patients treated with conventional medications.

RESULTS

Clinical manifestations and liver functions were significantly improved, namely, decreased levels of serum transaminases, total bilirubin, and bile acid, as well as increased levels of serum albumin following ALSS treatment. The 30-day survival rates of the patients who received ALSS versus controls were 47.9% versus 34.6%, respectively (P = .01). The MELD score and the stage of hepatic encephalopathy were highly associated with mortality (P < .001), but the sessions of ALSS showed a positive relation to the 30-day survival (P < .05).

CONCLUSIONS

ALSS appears to be efficacious and safe for the treatment of patients with AoCLF. Both model for end-stage liver disease (MELD) score and hepatic encephalopathy are useful to predict the mortality of patients.

Technology insight: liver support systems

Emergency orthotopic liver transplantation (OLT) is currently the only standard treatment for fulminant hepatic failure (FHF). The waiting time for transplantation can exceed a week-using a liver assist device to bridge patients with FHF to OLT might therefore decrease the mortality rate. Several liver support systems have been described, but no system has gained FDA approval or widespread clinical acceptance. Although the results of many experimental and clinical trials are encouraging, the field is still in its initial stages. Using nonbiologic liver support is based on the assumption that several toxins that cause hepatic coma can be removed from the circulation by blood or plasma sorption methods. As these toxins could be involved in many FHF complications recovery without the need for transplantation is the ultimate aim. Biologic liver support uses xenogeneic livers or hepatocytes to support the failed human liver, exploiting biological cell functions, namely detoxification, metabolism, and biosynthesis. The classical nonbiologic dialysis methods could decrease mortality in patients with acute-on-chronic liver failure, but definitive conclusions are impossible to draw because of the small number of patients studied and inadequate follow-up. Larger studies performed in specialty centers should provide conclusive data about the role of the bioartificial liver support system as a possible universal bridge to OLT. This article presents an overview of published experience with liver support systems since the 1960s.

Comparison of Plasma Exchange With Different Membrane Pore Sizes in the Treatment of Severe Viral Hepatitis

Plasma exchange has become an effective mode of blood purification in patients suffering from liver failure. To assist in patient recovery, we compared two plasma separators to identify a plasma separator with suitable pore sizes to remove toxic substances effectively, and retain important plasma components. The study focused on severe viral hepatitis patients. Of 206 rounds of plasma exchange, 137 were completed with the PS-06 plasma separator (membrane pore size=0.2 microm) and 69 with the EC-4A plasma separator (membrane pore size=0.03 microm). The efficacy of different plasma separators was compared using survival rate, changes in liver biochemistry, immunoglobulin, and complement parameters. The survival rate of patients treated with PS-06 was 43.3% (13 of 30 patients). For patients treated with EC-4A, two patients were bridged to liver transplantation successfully, and 57.9% (11 of 19 patients) survived. In both groups, the levels of total bilirubin, prothrombin time, and bile acid declined significantly. Compared to PS-06, EC-4A could retain significantly larger amounts of immunoglobulin and complements. Our study revealed that plasma exchange implementation with membrane pore size 0.03 microm could remove adequate bilirubin and bile acid, a class of toxins bound to plasma protein in severe viral hepatitis patients, and reduce the loss of essential plasma macromolecules.

Albumin and hydroxyethyl starch 130 kDa/0.4 improve filter clearance and haemocompatibility in haemo- and plasmafiltration—an in vitro study

BACKGROUND

Apart from their standard applications, haemofiltration (HF) and plasmafiltration (PF) may provide helpful therapy for sepsis, multiple organ- and acute liver-failure. Some colloids cause either decreases or increases in blood cell agglomeration. We hypothesized that solutions which reduce cell aggregability may lead to both improved filter clearance and better haemocompatibility due to decreasing rates of clogged hollow fibres.

METHODS

Heparinized porcine blood (5 IU/ml) was used in an in vitro circuit. The filter types tested were from GAMBRO: HF66D (effective membrane surface: 0.6 m2) and PF1000N (effective membrane surface: 0.15 m2). Albumin (ALB), hydroxyethyl starch (HES) 200/0.5, HES 130/0.4, gelatin (GEL) or normal saline (0.9%) were added to the blood (n = 6/group). Recirculation systems were run for 2 h. Spontaneous haemolysis and filter resistance >420 mmHg were selected as indications of maximal flow rates. Sieving coefficients were determined for 17 parameters at the lowest and highest blood flows and filtration rate.

RESULTS

Based on the filter types used, supplementation of ALB and HES130/0.4 led to an improved filter clearance without increasing the number of clogged capillary membranes or causing impaired haemocompatibility. Sieving coefficients for most solutes were independent of volume substitute and flow rate. Haemocompatibility and filter clearance deteriorated after addition of HES200 or GEL to the blood.

CONCLUSIONS

Under standardized in vitro conditions, we found that colloids which reduce cell aggregability cause improved HF- and PF-performance. This phenomenon may provide new options for higher clearances and may lead to new concepts in low dose anticoagulation.

Benign recurrent intrahepatic cholestasis with secondary renal impairment treated with extracorporeal albumin dialysis

Benign recurrent intrahepatic cholestasis (BRIC) is a rare autosomal recessive condition characterized by intermittent episodes of pruritus and jaundice that may last days to months. Treatment is often ineffective and symptoms, particularly pruritus, can be severe. Extracorporeal albumin dialysis (molecular adsorbent recycling system, MARS) is a novel treatment which removes albumin bound toxins including bilirubin and bile salts. We describe a case of a 34-year-old man with BRIC and secondary renal impairment who, having failed standard medical therapy, was treated with MARS. The treatment immediately improved his symptoms, renal and liver function tests and appeared to terminate the episode of cholestasis. We conclude that MARS is a safe and effective treatment for BRIC with associated renal impairment.

Bilirubin-adsorption in 23 critically ill patients with liver failure

PURPOSE

Previous studies suggest that high levels of bilirubin exert cytotoxic, neurotoxic and encephalopathic effects that themselves may lead to further deterioration of liver function and multiorgan failure. Although extracorporeal BA is not a causal therapy, there are case reports of clinical benefits of BA. The present retrospective study investigated the clinical utility and effectiveness of BA in 23 patients with liver failure.

METHODS

Twenty-three patients (61+/-11 years) with excessive hyperbilirubinemia (>25 mg/dL) after liver transplantation (n=7), partial liver resection (n=12) and others (n=4) were treated with BA (3.6 liters plasma per BA, BR350, Asahi) and followed for 45+/-8 days.

RESULTS

A mean of 6.6 treatments (3-16) were performed per patient. On average, a single BA treatment reduced bilirubin-levels from 31+/-12 to 23.7+/-9 mg/dL (p<0.001). Levels of bile acid were reduced from 41.8+/-6 to 33.5+/-5 mg/dL. The 30-day mortality was 50%. BA was able to halt and stabilize the progressive increase in bilirubin levels in all patients. In contrast to survivors, non-survivors were characterized by a repeated rapid rise in bilirubin levels after cessation of BA treatment.

CONCLUSIONS

BA is able to stabilize or decrease bilirubin levels in patients with liver failure. Our experience suggests that BA is a safe and promising short-term treatment option for patients with acute deterioration of hepatic function.

Clinical application of bioartificial liver support systems

OBJECTIVE

To review the present status of bioartificial liver (BAL) devices and their obtained clinical results.

BACKGROUND

Acute liver failure (ALF) is a disease with a high mortality. Standard therapy at present is liver transplantation. Liver transplantation is hampered by the increasing shortage of organ donors, resulting in high incidence of patients with ALF dying on the transplantation waiting list. Among a variety of liver assist therapies, BAL therapy is marked as the most promising solution to bridge ALF patients to liver transplantation or to liver regeneration, because several BAL systems showed significant survival improvement in animal ALF studies. Until today, clinical application of 11 different BAL systems has been reported.

METHODS

A literature review was performed using MEDLINE and additional library searches. Only BAL systems that have been used in a clinical trial were included in this review.

RESULTS

Eleven BAL systems found clinical application. Three systems were studied in a controlled trial, showing no significant survival benefits, in part due to the insufficient number of patients included. The other systems were studied in a phase I trial or during treatment of a single patient and all showed to be safe. Most BAL therapies resulted in improvement of clinical and biochemical parameters.

CONCLUSIONS

Bioartificial liver therapy for bridging patients with ALF to liver transplantation or liver regeneration is promising. Its clinical value awaits further improvement of BAL devices, replacement of hepatocytes of animal origin by human hepatocytes, and assessment in controlled clinical trials.

Astrocyte apoptosis: implications for neuroprotection

Astrocytes, the most abundant glial cell types in the brain, provide metabolic and trophic support to neurons and modulate synaptic activity. Accordingly, impairment in these astrocyte functions can critically influence neuronal survival. Recent studies show that astrocyte apoptosis may contribute to pathogenesis of many acute and chronic neurodegenerative disorders, such as cerebral ischemia, Alzheimer's disease and Parkinson's disease. We found that incubation of cultured rat astrocytes in a Ca(2+)-containing medium after exposure to a Ca(2+)-free medium causes an increase in intracellular Ca(2+) concentration followed by apoptosis, and that NF-kappa B, reactive oxygen species, and enzymes such as calpain, xanthine oxidase, calcineurin and caspase-3 are involved in reperfusion-induced apoptosis. Furthermore, we demonstrated that heat shock protein, mitogen-activated protein/extracellular signal-regulated kinase, phosphatidylinositol-3 kinase and cyclic GMP phosphodiesterase are target molecules for anti-apoptotic drugs. This review summarizes (1) astrocytic functions in neuroprotection, (2) current evidence of astrocyte apoptosis in both in vitro and in vivo studies including its molecular pathways such as Ca(2+) overload, oxidative stress, NF-kappa B activation, mitochondrial dysfunction, endoplasmic reticulum stress, and protease activation, and (3) several drugs preventing astrocyte apoptosis. As a whole, this article provides new insights into the potential role of astrocytes as targets for neuroprotection. In addition, the advance in the knowledge of molecular mechanisms of astrocyte apoptosis may lead to the development of novel therapeutic strategies for neurodegenerative disorders.

Role of Laboratory in the Management of Phenylbutazone Poisoning

We report a rare case of intentional overdose of phenylbutazone in a 15-yr-old female. The patient exhibited symptoms of phenylbutazone toxicity and the presence of the drug was confirmed by gas chromatography mass-spectrometry (GC-MS) analysis of the initial urine sample. The patient underwent plasmapheresis to remove the drug from the circulation. Semiquantitation of sequential serum samples by GC-MS revealed elimination of phenylbutazone by day 5 of admission at which time the plasmapheresis was discontinued. Elevated blood urea nitrogen (BUN) and creatinine returned to normal. Analysis of biomarkers for liver necrosis and regeneration in sequential serum samples revealed the restoration of normal liver function by day 5. This case further confirms our previous observations that biomarkers for liver necrosis and regeneration can predict the outcome of patients with liver damage due to toxins.