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 micromol/l (P < 000.1). A similar reduction in plasma acyl-carnitine levels was observed (from 13.22 +/- 1.34 to 6.24 +/- 1.20 micromol/l (P < 0.001)). The AC:FC ratio improved from 0.51 +/- 0.03 to 0.39 +/- 0.03 (P < 0.005) (Normal < 0.25).


CONCLUSIONS
NHD is associated with an improvement in AC:FC ratio. Further research is needed to examine the longitudinal clinical impact of this metabolic correction and to examine whether this effect is sustained.
Hothi
Daljit K
DK
Division of Pediatric Nephrology, Toronto General Hospital, Toronto, Canada.
Geary
Denis F
DF
Fisher
Lawrence
L
Chan
Christopher T
CT
D000328:Adult; D001685:Biological Factors; D002331:Carnitine / Q000031:analogs & derivatives / Q000097:blood*; D002940:Circadian Rhythm / Q000502:physiology*; D003124:Colorimetry; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D006435:Renal Dialysis; D013997:Time Factors
D001685:Biological Factors; C116917:acylcarnitine; D002331:Carnitine