Short-term effects of nocturnal haemodialysis on carnitine metabolism

Background. Functional carnitine deficiency [as indicated by an abnormal acyl-carnitine/free-carnitine (AC:FC) ratio] is commonly seen in patients with end-stage renal disease (ESRD), resulting in significant clinical detriments including anaemia, cardiomyopathy and muscle weakness. Nocturnal haemodialysis (NHD) (5–6 sessions per week, 8 h per treatment) has been reported to reverse several surrogate markers of uraemia. Conversely, as a consequence of increased dialysis dose, NHD may have the potential to aggravate plasma nutrient deficiencies. Our objective was to determine the effects of NHD on plasma free-carnitine levels and carnitine metabolism. Methods. We conducted an observational cohort study with a before and after design. Nine ESRD patients (age: 47 ± 3; mean ± SEM) were studied. Routine biochemical, haemodynamic and carnitine metabolic products were analysed at baseline while on conventional haemodialysis and 2 months post-conversion to NHD. Free-carnitine and total-carnitine levels were generated by colorimetric assays. The difference between total- and free-carnitine concentrations was estimated to be the acyl-carnitine level. Paired t-test was used to ascertain statistical significance. Results. After conversion to NHD, there was a significant increase in urea clearance in all patients. Plasma free-carnitine levels fell from 26.54 ± 2.99 to 15.6 ± 2.34 μmol/l (P