Removal of the uremic retention solute p-cresol using fractionated plasma separation and adsorption

Removal of protein-bound uremic retention solutes, including p-cresol, by peritoneal dialysis and hemodialysis (HD) is limited. p-Cresol, mainly circulating as sulfate conjugate (p-cresyl sulfate [PCS]), is independently associated with mortality. Fractionated plasma separation and adsorption (FPSA) is a nonbiologic detoxification system for the treatment of liver failure. The FPSA clearance of uremic retention solutes is unknown. We studied PCS clearance by FPSA, using the Prometheus system. The neutral resin adsorbent and the anion exchange adsorbent bind PCS in vitro (reduction ratios [RRs] 37 and 70%). Ex vivo, the adsorbent mass removal (MR) (median 47.5 mg) contributes more than half to total MR (median 89.6 mg). In vivo, PCS RR during FPSA (50%) exceeded the RR during high flux HD (30%). We halted the study after four inclusions due to repeated thrombosis of the arterio-venous conduit. In conclusion, FPSA is a promising technique to improve clearance of protein-bound uremic retention solutes.