Effect of hemodiabsorption and sorbent-based pheresis on amino acid levelsin hepatic failure

Changes in plasma amino acid concentrations were measured in patients with hepatic failure during extracorporeal hemodiabsorption (using the Liver Dia lysis Unit, "the Unit") or hemodiabsorption plus sorbent-based pheresis tre atment (using the Liver Dialysis Plasmafilter Unit, "the PFE-Unit") Systems . Eight patients with hepatic failure, grade 3 or 4 encephalopathy, elevated bilirubin and/or creatinine levels and respiratory or renal failure were tr eated for 1-3 days with the Unit alone. Three of these were also treated wi th the Unit containing 10 g of BCAA in the sorbent suspension. Four patient s with hepatic failure treated with the PF Unit also had 10 LI of branched chain amino acid (BCAA) added to the sorbents of the Unit portion of this d evice. Pre- and post-plasma samples were drawn and high performance liquid chromatography (HPLC) was used to separate and detect amino acids in the pl asma. Both the Unit and the RE-Unit have the capability to selectively remove var ious amino acids, especially aromatic amino acids (AAA). The pre-treatment amino acid profiles of plasma were typical for hepatic failure, with abnorm ally high levels of phenylalanine, tyrosine, tryptophan, and methionine and decreased levels of valine, leucine and isolucine. The average pre-treatment Fischer ratio (BCAA/AAA) for both Unit and RE-Uni t patients was 1.43 (+/-0.58). Treatments by both systems resulted in an in crease of BCAA levels in blood and concomitant decrease of AAA levels, with an average Fischer ratio improvement of 30-38% for the Unit and RE-Unit wi thout BCAA. The Fischer ratio improved by 90% (average) for the Unit with B CAA. Levels of many other amino acids (such as alanine, glycine, proline or lysine) increased during both Unit and RE-Unit treatments. The removal of strongly protein-bound toxin and amino acids such as tryptophan and sulphyd ryl amino acids was more effective by the RE-Unit. Both the Unit and the RE-Unit have the unique capability to remove toxic ar omatic amino acids while increasing BCAA levels in patient. The increase in many amino acid levels may be related to the removal of toxins that interf ere with normal amino acid metabolism. The addition of the PF module improv es the removal of bilirubin and similarly protein-bound chemicals. Changes in amino acid profiles by the Unit and the RE-Unit contrast markedly with o ther extracorporeal devices.