Jan Stange

Randomized controlled study of extracorporeal albumin dialysis for hepatic encephalopathy in advanced cirrhosis

Extracorporeal albumin dialysis (ECAD) may improve severe hepatic encephalopathy (HE) in patients with advanced cirrhosis via the removal of protein or non–protein‐bound toxins. A prospective, randomized, controlled, multicenter trial of the efficacy, safety, and tolerability of ECAD using molecular adsorbent recirculating system (MARS) was conducted in such patients. Patients were randomized to ECAD and standard medical therapy (SMT) or SMT alone. ECAD was provided daily for 6 hours for 5 days or until the patient had a 2‐grade improvement in HE. HE grades (West Haven criteria) were evaluated every 12 hours using a scoring algorithm. The primary endpoint was the difference in improvement proportion of HE between the 2 groups. A total of 70 subjects [median age, 53; 56% male; 56% HE grade 3; 44% HE grade 4; median model for end‐stage liver disease (MELD) 32 (11–50) and CPT 13 (10–15)] were enrolled in 8 tertiary centers. Patients were randomized to ECAD + SMT (n = 39) or SMT alone (n = 31). Groups were matched in demographics and clinical variables. The improvement proportion of HE was higher in ECAD (mean, 34%; median, 30%) versus the SMT group (mean, 18.9%; median, 0%) (P = 0.044) and was reached faster and more frequently than in the SMT group (P = 0.045). Subjects receiving ECAD tolerated treatment well with no unexpected adverse events. Conclusion: The use of ECAD may be associated with an earlier and more frequent improvement of HE (grade 3/4). Because this 5‐day study was not designed to examine the impact of MARS on survival, a full assessment of the role of albumin dialysis awaits the results of additional controlled trials. (HEPATOLOGY 2007.)

A new procedure for the removal of protein bound drugs and toxins

To extend the applicability of dialysis to the removal of albumin bound toxins, a new dialysis procedure was developed. A double sided albumin impregnated high-flux polysulfon dialyzer was used together with a closed loop dialysate compartment with an albumin containing dialysate solution, that was purified on line in a three step process with a charcoal and resin adsorbent, and another dialyzer for a normal dialysis or filtration of the albumin containing dialysate that was then recycled to the albumin impregnated dialyzer. The system effectively removed strongly albumin bound toxins like unconjugated bilirubin or free fatty acids from plasma and blood in vitro and in vivo and therefore could be considered a possible therapeutic means for the treatment of acute liver failure or acute and chronic intoxications with albumin bound toxins, e.g., in drug overdose or chronic renal failure.

Targeted chemotherapy by intratumour injection of encapsulated cells engineered to produce CYP2B1, an ifosfamide activating cytochrome P450.

The prognosis of pancreatic adenocarcinoma is poor and current treatment ineffective. A novel treatment strategy is described here using a mouse model system for pancreatic cancer. Cells that have been genetically modified to express the cytochrome P450 2B1 enzyme are encapsulated in cellulose sulphate and implanted into pre-established tumours derived from human pancreatic cells. Cytochrome P450 2B1 converts the chemotherapeutic agent ifosfamide to toxic metabolites. Administration of ifosfamide to tumour-bearing mice that were recipients of implanted encapsulated cells results in partial or even complete tumour ablation. These results suggest that in situ chemotherapy with genetically modified cells in an immunoprotected environment may prove useful for application in man.

Systemic long-term delivery of antibodies in immunocompetent animals using cellulose sulphate capsules containing antibody-producing cells.

Implantation of capsules containing antibody-producing cells into patients would potentially permit systemic long-term delivery of antibodies and might, thus, be useful in the development of surveillance treatments for cancers and severe viral diseases. We show that cellulose sulphate (CS) capsules containing hybridoma cells, when implanted subcutaneously or in the intraperitoneal cavity, can be used for delivering monoclonal antibodies into the blood- stream of immunocompetent mice for at least several months. In contrast to capsules implanted into the intraperitoneal cavity, which remain mobile and nonvascularized, capsules implanted under the skin form neo-organs which become vascularized within days. This may explain the higher blood concentration of the antibody we have observed in the latter case. Importantly, neither an isolating fibrosis nor an obvious inflammatory response was detected at the capsule implantation sites during observation periods as long as 10 months. Finally, no anti-idiotypic immune response against the ectopically delivered antibody was shown to occur. This rules out any potent adjuvant effect of the cellulose sulphate matrix that might have stimulated a neutralizing humoral response. Taken together, our data indicate that encapsulation of antibody-producing cells into CS might be used in antibody-based gene/cell therapy approaches.

Performance of the Hepatic Encephalopathy Scoring Algorithm in a Clinical Trial of Patients With Cirrhosis and Severe Hepatic Encephalopathy

OBJECTIVES:The grading of hepatic encephalopathy (HE) is based on a combination of indicators that reflect the state of consciousness, intellectual function, changes in behavior, and neuromuscular alterations seen in patients with liver failure.METHODS:We modified the traditional West Haven criteria (WHC) to provide an objective assessment of the cognitive parameters to complement the subjective clinical ratings for the performance of extracorporeal albumin dialysis (ECAD) using a molecular adsorption recirculating system in patients with cirrhosis and severe (grade III/IV) encephalopathy. The HE Scoring Algorithm (HESA) combined clinical indicators with those derived from simple neuropsychological tests, the latter more often used in milder grades of HE (I/II). The performance of each indicator was compared across grades and sites.RESULTS:Results of HESA were also compared with the Glasgow Coma Scale. A total of 597 evaluations were performed in patients randomized to ECAD plus standard medical therapy or the latter only. Most parameters exhibited significant separation between grades; the most effective indicators were lack of verbal, eye, and motor response (grade IV), somnolence and disorientation to place (grade III), and lethargy and disorientation to time (grade II). Two clinical and four neuropsychological indicators were useful to classify patients as grade I. The Glasgow Coma Scale differed among the four stages of the WHC, but the differences between grades I and II were small and not clinically useful.CONCLUSION:HESA extends the traditional WHC for grading HE. In the absence of a “gold” standard, the most useful indicators noted in this trial should be further validated.

Albumin Regeneration in Liver Support—Comparison of Different Methods

Abstract:  Albumin is the most abundant human plasma protein. Among many other functions it is an important transporter of hydrophobic internal and external substances such as intermediate and end products of metabolism and drugs. In liver failure the albumin binding capacity is decreased because of a disproportion between available albumin molecules caused by decreased hepatic synthesis and hydrophobic toxins because of decreased hepatic clearance. The resulting increase in plasma and tissue concentrations of these substances is associated with multiple organ dysfunctions frequently seen in severe liver failure. The scope of the present article is to compare different liver support strategies with regard to their ability to regenerate the patients albumin pool by removing albumin‐bound toxins. Most prominent technique in this group is the molecular adsorbent recirculating system (MARS). It will be compared with single pass albumin dialysis (SPAD), fractionated plasma separation and adsorption system (FPSA, Prometheus), and plasma perfusion/bilirubin adsorption with special regard to efficacy and selectivity.

Albumin dialysis MARS: knowledge from 10 years of clinical investigation.

A decade ago, albumin dialysis was introduced as a new extracorporeal detoxification method for patients with liver failure. Today, the molecular adsorbent recirculating system is the most frequently used type of albumin dialysis and most studied liver-support technique. Numerous preclinical and clinical studies demonstrated the importance of albumin as a scavenger for molecules with pathophysiological relevance in liver failure. Albumin dialysis enables the selective regeneration of albumin. The resulting increase of albumin binding capacity is paralleled by improvement of central and local hemodynamics and liver, brain, and kidney functions. The treatment can contribute to liver regeneration and prolongation of patient survival in the context of acute liver failure, decompensated chronic liver disease, and bridging of patients to liver transplantation. Proper patient selection is critical for clinical success. Aggressive treatment of infections and sepsis seems to be a decisive prerequisite for its safe and efficient use. Cautious anticoagulation with heparin is the common standard. Citrate use is recommended for patients prone to bleeding. Taken together, albumin dialysis represents a valuable therapeutic tool for the treatment of various types of liver failure. Ongoing and future studies will help define the optimal patient selection and technical process parameters such as session length and frequency of treatment.

Improvement of impaired albumin binding capacity in acute‐on‐chronic liver failure by albumin dialysis

Extracorporeal albumin dialysis (ECAD) enables the elimination of albumin bound substances and is used as artificial liver support system. Albumin binding function for the benzodiazepine binding site specific marker Dansylsarcosine was estimated in plasma samples of 22 patients with cirrhosis and hyperbilirubinaemia (ECAD: n = 12; control: n = 10) during a period of 30 days in a randomized controlled clinical ECAD trial. Albumin Binding Capacity (ABiC) at baseline was reduced to 31.8% (median; range 24%‐74%) and correlated to the severity of liver disease. Within two weeks a significant improvement of ABiC and a reduction of the albumin bound markers bilirubin and bile acids were observed in the ECAD group. During single treatments a significant decrease of albumin bound substances (bilirubin and bile acids) as well as an increase in ABiC was observed. In the control group, baseline ABiC was significantly lower in patients who died during study period (34.2% vs. 41.7%; P < 0.028), whereas no significant differences were observed for CHILD, coagulation factors, albumin, bile acids nor bilirubin. At baseline 13 patients had a severely impaired ABiC (<40%), improvement of ABiC was more frequent in the ECAD group (5/6) than in the SMT group (2/7). Reduced albumin binding function is present in decompensated liver failure and is related to severity and 30 day survival. ABiC can be improved by ECAD. The beneficial effect of this treatment may be related to the improvement of albumin binding function more than to the elimination of specific substances. Characterization of albumin function by the ABiC test may help to evaluate different liver support systems and other therapeutic measures. Liver Transpl 14:1333–1339,2008.

Binding of bilirubin and bromosulphthalein to albumin: Implications for understanding the pathophysiology of liver failure and its management

The binding/transporting functions of albumin provide the rationale for using albumin dialysis (e.g., molecular adsorbents recirculating system [MARS]) in liver failure. This study investigates these properties in vitro, validating the findings in vivo. In vitro bromosulphthalein (BSP) and bilirubin‐spiked plasma were dialyzed against albumin and sampled. In vivo serum biochemistry was analyzed in: 7 MARS‐treated liver failure patients; 98 MARS‐treated patients from the MARS Registry; and 8 patients receiving albumin infusion. In vitro BSP concentrations did not equilibrate, but the molar ratio of BSP to albumin (CBSP/Calb) did, with no subsequent transmembrane transport, suggesting that the CBSP/Calb gradient (rather than simple diffusion) drives BSP transport. Bilirubin was transported similarly. In vivo serum bilirubin reduction during MARS sessions (n = 26) correlated with pre‐treatment bilirubin (r = 0.42), but better (r = 0.85) with pre‐treatment molar ratio of bilirubin to albumin (Cbilirubin/Calb). The strongest correlation was between Cbilirubin/Calb reduction and pre‐treatment Cbilirubin/Calb (r = 0.9). A similar pattern was observed in the MARS Registry patients. After albumin infusion (n = 8), both serum albumin and bilirubin increased, while Cbilirubin/Calb remained unchanged. Cbilirubin/Calb appears to be important in albumin dialysis, and generally in liver disease patients, reinforcing the importance of the toxin‐binding functions of albumin in liver disease. (Liver Transpl 2004;10:1531–1538.)

Treatment of Thyrotoxic Crisis With Plasmapheresis and Single Pass Albumin Dialysis: A Case Report

Thyrotoxic crisis (thyroid storm) is a life-threatening condition. Standard therapy is based on thiamazole, prednisolone, and nonselective beta-blockers. Extracorporeal plasmapheresis is an additional tool for removing circulating thyroxine in patients who do not respond quickly to conventional standard therapy. As thyroxine can be bound by albumin, the aims of the present therapy report were to investigate the potential of extracorporeal single-pass albumin dialysis (SPAD) to remove thyroid hormones and to compare it with plasmapheresis. A 68-year-old female with thyrotoxic crisis refractory to conventional therapy underwent two sessions of plasmapheresis without clinical response. For the treatment dose to be increased, the patient was then treated with a modified continuous veno-venous hemodialysis with a dialysate containing 4% of human serum albumin (SPAD) intended to bind and remove thyroxines continuously. In total, the patient received three sessions of plasmapheresis and four SPAD treatments. Thyroxine levels were detected in the patient and in exchanged plasma or albumin dialysate, respectively, to calculate the amount removed. The main finding was that SPAD treatments were tolerated well by the patient. Due to continuous approach, SPAD sessions removed more thyroid hormone than plasmapheresis did, resulting in the improvement of the clinical status of the patient (reduction of heart rate and catecholamine dosage), which enabled bridging the patient to thyroidectomy as the ultimate surgical treatment. This is the first clinical report of the use of albumin dialysis in thyroid storm. SPAD represents a safe and efficient alternative to plasmapheresis as it can be performed continuously in this critical condition.