TY - JOUR
T1 - L-Carnitine Improves Skeletal Muscle Fat Oxidation in Primary Carnitine Deficiency
AU - Madsen, Karen Lindhardt
AU - Preisler, Nicolai
AU - Rasmussen, Jan
AU - Hedermann, Gitte
AU - Olesen, Jess Have
AU - Lund, Allan Meldgaard
AU - Vissing, John
PY - 2018
Y1 - 2018
N2 - Context: Primary carnitine deficiency (PCD) is an inborn error of fatty acid metabolism. Patients with PCD are risk for sudden heart failure upon fasting or illness if they are not treated with daily L-carnitine. Objective: To investigate energy metabolism during exercise in patients with PCD with and without L-carnitine treatment. Design: Interventional study. Setting: Hospital exercise laboratories and department of cardiology. Participants: Eight adults with PCD who were homozygous for the c.95A>G (p.N32S) mutation and 10 healthy age- and sex-matched controls. Intervention: Four-day pause in L-carnitine treatment. Main outcome measures: Total fatty acid and palmitate oxidation rates during 1-hour submaximal cycle ergometer exercise assessed with stable isotope method (U 13 C-palmitate and 2 H 2 -D-glucose) and indirect calorimetry with and without L-carnitine. Results: Total fatty acid oxidation rate was higher in patients with L-carnitine treatment during exercise than without treatment [12.3 (SD, 3.7) vs 8.5 (SD, 4.6) mmol × kg 21 × min 21 ; P = 0.008]. However, the fatty acid oxidation rate was still lower in patients treated with L-carnitine than in the healthy controls [29.5 (SD, 10.1) mmol × kg 21 × min 21 ; P< 0.001] and in the L-carnitine group without treatment it was less than one third of that in the healthy controls (P< 0.001). In line with this, the palmitate oxidation rates during exercise were lower in the no-treatment period [144 (SD, 66) μmol × kg 21 × min 21 ] than during treatment [204 (SD, 84) μmol × kg 21 × min 21 ; P = 0.004) . Conclusions: The results indicate that patients with PCD have limited fat oxidation during exercise. L-Carnitine treatment in asymptomatic patients with PCD may not only prevent cardiac complications but also boost skeletal muscle fat metabolism during exercise.
AB - Context: Primary carnitine deficiency (PCD) is an inborn error of fatty acid metabolism. Patients with PCD are risk for sudden heart failure upon fasting or illness if they are not treated with daily L-carnitine. Objective: To investigate energy metabolism during exercise in patients with PCD with and without L-carnitine treatment. Design: Interventional study. Setting: Hospital exercise laboratories and department of cardiology. Participants: Eight adults with PCD who were homozygous for the c.95A>G (p.N32S) mutation and 10 healthy age- and sex-matched controls. Intervention: Four-day pause in L-carnitine treatment. Main outcome measures: Total fatty acid and palmitate oxidation rates during 1-hour submaximal cycle ergometer exercise assessed with stable isotope method (U 13 C-palmitate and 2 H 2 -D-glucose) and indirect calorimetry with and without L-carnitine. Results: Total fatty acid oxidation rate was higher in patients with L-carnitine treatment during exercise than without treatment [12.3 (SD, 3.7) vs 8.5 (SD, 4.6) mmol × kg 21 × min 21 ; P = 0.008]. However, the fatty acid oxidation rate was still lower in patients treated with L-carnitine than in the healthy controls [29.5 (SD, 10.1) mmol × kg 21 × min 21 ; P< 0.001] and in the L-carnitine group without treatment it was less than one third of that in the healthy controls (P< 0.001). In line with this, the palmitate oxidation rates during exercise were lower in the no-treatment period [144 (SD, 66) μmol × kg 21 × min 21 ] than during treatment [204 (SD, 84) μmol × kg 21 × min 21 ; P = 0.004) . Conclusions: The results indicate that patients with PCD have limited fat oxidation during exercise. L-Carnitine treatment in asymptomatic patients with PCD may not only prevent cardiac complications but also boost skeletal muscle fat metabolism during exercise.
U2 - 10.1210/jc.2018-00953
DO - 10.1210/jc.2018-00953
M3 - Journal article
C2 - 30219858
SN - 0021-972X
VL - 103
SP - 4580
EP - 4588
JO - The Journal of clinical endocrinology and metabolism
JF - The Journal of clinical endocrinology and metabolism
IS - 12
ER -