Removal of branched-chain amino acids by peritoneal dialysis, continuous arteriovenous hemofiltration, and continuous arteriovenous hemodialysis in rabbits: implications for maple syrup urine disease treatment.

Renal elimination of branched-chain amino acids (BCAA) is low in maple syrup urine disease, and peritoneal dialysis may be required in an emergency situation for removal of the three BCAA (leucine, isoleucine, and valine). However, failures of BCAA removal by peritoneal dialysis have been reported, especially in neonates. Therefore, we tested the ability of continuous hemofiltration and continuous hemodialysis to remove BCAA as compared with peritoneal dialysis. Experiments were conducted in 15 anesthetized adult rabbits infused with leucine, isoleucine, and valine. In group 1 (n = 7), peritoneal dialysis (dialysate = 75 mL/kg) and continuous arteriovenous hemofiltration with a polysulfone 800-cm2 hemofilter were simultaneously performed during 40 min. In group 2 (n = 8), continuous arteriovenous hemofiltration and continuous arteriovenous hemodialysis were successively performed during 30 min in a randomly settled order. Animals had high and stable BCAA plasma levels during the experimental procedure. As compared with peritoneal dialysis, continuous arteriovenous hemofiltration constantly showed a significant increase in clearances of leucine (+159 +/- 99%), isoleucine (+176 +/- 107%), and valine (+125 +/- 76%). In comparison with continuous arteriovenous hemofiltration, continuous arteriovenous hemodialysis constantly showed significant increased values in clearances of leucine (+90 +/- 43%), isoleucine (+95 +/- 45%), and valine (+99 +/- 52%). During continuous arteriovenous hemofiltration and continuous arteriovenous hemodialysis, a significant positive correlation was established between urea clearance and clearances of leucine (r2 = 0.953 and 0.927, respectively), isoleucine (r2 = 0.948 and 0.910, respectively), and valine (r2 = 0.953 and 0.864, respectively).