Elevated Plasma Carnitine Levels in Patients on CAPD

Abstract

Carnitine, a small-molecular-weight quarternary amine, is lost from the plasma during hemodialysis in patients with chronic renal failure. Reports are conflicting concerning plasma carnitine levels in patients on continuous ambulatory peritoneal dialysis (CAPD). We studied 35 patients on CAPD for varying durations (up to 70 months) and noted a significant elevation in plasma levels of total carnitine, 62.98 ± 19.76 Uμmol/l; M ± SD) when compared to levels in healthy controls, 50.45 ± 8.7 (p < .005). This elevation in total carnitine level was due entirely to increases in esterified carnitine fractions in the patients 27.05 ± 11.8 when compared to control values, 7.93 ± 3.3 (p < .001). Plasma levels of free carnitine were similar in patients, 38.05 ± 13.7 and controls, 42.5 ± 8.14. In nine patients repeat plasma carnitine determinations 29 months after the initial studies showed no significant changes. Despite loss of carnitine in the peritoneal dialysate, plasma carnitine levels do not fall in patients on CAPD. At present, no one knows why plasma levels of esterified car nitine are elevated in patients on CAPD; this requires further study.