Detoxifying Capacity and Kinetics of the Molecular Adsorbent Recycling System: Contribution of the Different Filters Inbuilt

Abstract

Extracorporeal liver support therapies have been used for several decades as a bridging therapy prior to liver transplantation or as an addendum to standard medical therapy. The molecular adsorbent recycling system (MARS) represents a cell‐free, extracorporeal, liver assistance method for the removal of both albumin‐bound and water‐soluble endogenous toxins. The aim of the present study was to evaluate the short‐and long‐term removal capacity and selectivity of the different inbuilt dialysers and adsorption columns (uncoated charcoal, anion exchanger resin). Levels of endogenous toxins and parameters of hepatic synthesis and necrosis were therefore monitored before, during, and after the MARS treatment phase in 10 patients. Moreover, blood and dialysate clearances of urea nitrogen, creatinine, bilirubin and bile acids were determined during a single treatment. The significant increasing time course of total bilirubin blood levels before the start of the treatment could be stopped and reversed in a significant decreasing time course (Linear Mixed Models, P < 0.05). The removal rate of urea nitrogen, bilirubin, and bile acids during a single treatment amounted to 55.5 ± 4.0%, 28.3 ± 3.9%, and 55.4 ± 4.0%(mean ± SEM), respectively. Bile acids and bilirubin were mainly removed by the activated charcoal and anion exchanger column, respectively. The efficacy of removal of albumin‐bound toxins sharply declined early after initiation of the treatment to become negligible after 6 h. In conclusion, both albumin‐bound and water‐soluble toxins are adequately removed by the MARS. Our data suggest that the rate and efficacy of removal of albumin‐bound toxins is related to both the strength of the albumin binding and the saturation of the adsorption columns.

Removal of Bile Acids by Two Different Extracorporeal Liver Support Systems in Acute-on-Chronic Liver Failure

“…Stange et al 21 reported a blood clearance of 36 Ϯ 9 mL/min for total bile acids with the MARS system (time point not given). More recently, Evenepoel et al 22 reported blood clearances for total bile acids with MARS of 65 Ϯ 15 mL/min at 1 hour and 53 Ϯ 12 mL/min at 6 hours. In a recent study using Prometheus, a blood clearance for total bile acids of 85 Ϯ 5 mL/min was found at 0.5 hours, which decreased to 45 Ϯ 13 mL/min at 6 hours.…”

“…20 Removal of total bile acids by MARS or Prometheus has been reported by several authors. 6,19,[21][22][23] Presently, no data exist on the respective effects of MARS and Prometheus on elimination of individual bile acids. The aim of this study was to investigate the elimination of individual bile acids by MARS and Prometheus in a randomized, cross-over design.…”

Effect of the molecular adsorbent recirculating system and Prometheus devices on systemic haemodynamics and vasoactive agents in patients with acute-on-chronic alcoholic liver failure

“…More specifically, for MARS the dialysate was sampled with a syringe from the closed loop circuit immediately after the MARS flux, whereas in the PROMETHEUS system the equivalent location was immediately after passage through the AlbuFlow. If elimination was found, the treatment phase percentage reduction rate (RR T ) was calculated: RR T = 100 × (1 - C after /C before ), with C after and C before being the serum level before and after treatment, as described elsewhere [23,24]. …”

Letter to the Editors

“…3 The concentration of the free component not only depends on the molar ratio of the toxin to albumin but also on its affinity to the carrier molecule (binding constant) and the interaction with other protein-bound substances. 4 The free concentration gradient can be increased by increasing the dialysate flow 2 or by adding albumin as a carrier to the dialysate, as is performed during albumin dialysis. 1 Figure 6 from the paper by Steiner et al suggests a transmembrane transport of unconjugated bilirubin that is almost equal to the transmembrane transport of bromosulphtalein.…”