Increasing the Clearance of Protein-Bound Solutes by Recirculating Dialysate through Activated Carbon

Abstract

Pointsc Conventional hemodialysis provides limited clearance of uremic solutes that bind to plasma proteins. c No studies have yet tested whether increasing the clearance of bound solutes provides clinical benefit. c Practical means to increase the dialytic clearance of bound solutes are required to perform such studies.

Precision Hemodialysis Using Sorbents to Remove Protein-Bound Uremic Toxins

“…When operated in series, the clearances of the carbon-regenerated dialysis system and regular dialysis system had clearances for PBUT that were additive. 1 Addition of an activated carbon block to the dialysis apparatus has implications for all types of dialyses as we now perform it. If a portion of effluent dialysate from any dialyzer were diverted through a carbon block column and then pumped into the inflowing dialysate, the dialysate use rate could remain the same, but the dialysate flow through the dialyzer would be increased.…”

“…7,8 Meyer and colleagues have proven that the prediction of Patzer was correct-in a study of PBUT removal rather than liver failure toxins. 1 In his studies, a conventional system provided clearances of approximately 18 ml/min for p-cresol sulfate and 19 ml/min for indoxyl sulfate when dialyzing blood with these tightly bound solutes. The dialyzers with the carbon-block recirculating system had clearances of approximately 45 ml/min for p-cresol sulfate and 61 ml/min for indoxyl sulfate when operating alone, without removing small toxins such as urea.…”

“…In this issue of Kidney360 , Meyer et al show how to make a dialysis device highly selective for PBUTs. 1 Surprisingly, their technique does not use formerly developed systems with a sorbent compound in suspension and powdered carbon outside the dialysis membrane as in BioLogic-DT (Liver Dialysis Unit) 2 or fractionated plasma separation and adsorption as in Prometheus 3 or a dialysate-containing albumin for sorption as in the molecular adsorbent recirculating system (MARS), 4 or a hemofiltration membrane with a sorbent column to remove the toxins from filtrate as in the Supra-Hemofiltration with Reinfusion device. 5 Rather, this simple but very effective PBUT-removing device comprises two large standard permeability dialyzers, a high dialysate flow of 1000 ml/min, and dialysate regeneration by a carbon block column (powdered carbon in a polymeric scaffold).…”

“…When operated in series, the clearances of the carbon-regenerated dialysis system and regular dialysis system had clearances for PBUT that were additive. 1 …”