Abstracts Division 3
55. Branched-chain ketoacid co-ingestion with protein lowers amino acid oxidation during hemodialysis
Floris K. Hendriks1,2, Jorn Trommelen1, Frank M. van der Sande2,3, Janneau M.X. van Kranenburg1, Jeffrey H.W. Kuijpers4, Dion Houtvast1, Guus Jetten1, Joy P.B. Goessens1, Steven J.R. Meex4, Jeroen P. Kooman2,3, and Luc J.C. van Loon1.
1Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
2Department of Internal Medicine, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
3Division of Nephrology, Department of Internal Medicine, Maastricht University Medical Centre+, Maastricht, The Netherlands
4Department of Clinical Chemistry, Central Diagnostic Laboratory, Maastricht University Medical Center+, Maastricht, The Netherlands
Background
Hemodialysis removes amino acids from the circulation, thereby stimulating muscle catabolism. Protein ingestion during hemodialysis can compensate for amino acid removal but will also increase uremic toxin production. In contrast, branched-chain ketoacid (BCKA) ingestion can provide an anabolic stimulus without adding to uremic toxin accumulation. In the present study we assessed the impact of BCKA co-ingestion with protein during hemodialysis on forearm amino acid balance, amino acid removal, and amino acid oxidation.
Methods
Nine patients (age: 73±10 y, BMI: 26.5±4.1 kg/m2) on chronic hemodialysis treatment participated in this double-blind crossover trail. During two 4-h hemodialysis sessions, patients ingested 18 g protein with (PRO+BCKA) or without (PRO) 9 g BCKAs in a randomized order. Test beverages were labeled with L-[ring-13C6]-phenylalanine and provided throughout the last 3 h of hemodialysis as 18 equal sips with 10-min intervals. Arterial and venous plasma, spent dialysate, and breath samples were collected throughout hemodialysis and analyzed by mass spectrometry.
Results
Plasma total amino acid (TAA) concentrations during PRO and PRO+BCKA interventions were significantly lower after 1 h of hemodialysis (2.6±0.3 and 2.6±0.3 mmol/L, respectively) when compared to pre-hemodialysis concentrations (4.2±1.0 and 4.0±0.5 mmol/L, respectively; time effect: P<0.001). Throughout test beverage ingestion plasma TAA concentrations increased over time (time effect: P=0.027) without differences between interventions (time*treatment: P=0.62). Forearm arteriovenous TAA balance during test beverage ingestion did not differ between timepoints (time effect: P=0.31) or interventions (time*treatment: P=0.34). Amino acid (24.0±7.6 vs. 22.8±9.3 g; P=0.62) and urea removal (19.5±7.0 vs. 18.8±6.5 g; P=0.33) did not differ between PRO and PRO+BCKA interventions, respectively. Amino acid oxidation was 33±16% lower during PRO+BCKA when compared to PRO interventions (P<0.001).
Conclusion
BCKA co-ingestion with protein during hemodialysis does not further improve forearm net protein balance but lowers amino acid oxidation throughout hemodialysis.
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