Accumulation of trimethylamine and trimethylamine-N-oxide in end-stage renal disease patients undergoing haemodialysis

Background. Trimethylamine (TMA) is a short-chain tertiary aliphatic amine that is derived from the diet either directly from the consumption of foods high in TMA or by the intake of food high in precursors to TMA, such as trimethylamine-N-oxide (TMNO), choline and l-carnitine. The clinical significance of TMA may be related to its potential to contribute to neurological toxicity and 'uraemic breath' in patients with end-stage renal disease (ESRD). Methods. Concentrations of TMA and TMNO in plasma from 10 healthy adults (not on haemodialysis) and 10 adults with ESRD undergoing haemodialysis (pre- and post-dialysis) were determined by gas chromatography-mass spectrometry. Results. The concentrations of TMA and TMNO in pre-dialysis plasma (1.39 +/- 0.483 and 99.9 +/- 31.9 mu M, respectively) were significantly (P < 0.05) higher than the corresponding levels in healthy subjects (0.418 +/- 0.124 and 37.8 +/- 20.4 mu M, respectively). However, there were no significant differences between post-dialysis and healthy subject plasma concentrations. In the ESRD patients, there was a significant (P < 0.05) reduction in plasma TMA (from 1.39 +/- 0.483 to 0.484 +/- 0.164 mu M) and TMNO (from 99.9 +/- 31.9 to 41.3 +/- 18.8 mu M) during a single haemodialysis session. Conclusions. TMA and TMNO accumulate between haemodialysis sessions in ESRD patients, but are efficiently removed during a single haemodialysis session.