Triacylglycerol infusion improves exercise endurance in patients with mitochondrial myopathy due to complex I deficiency.
BACKGROUND
A high-fat diet has been recommended for the treatment of patients with mitochondrial myopathy due to complex I (NADH dehydrogenase) deficiency (CID).


OBJECTIVE
This study evaluated the effects of intravenous infusion of isoenergetic amounts of triacylglycerol or glucose on substrate oxidation, glycolytic carbohydrate metabolism, and exercise endurance time and energy state of muscle in CID patients.


METHODS
Four CID patients and 15 control subjects were infused with triacylglycerol (3.7 mg x kg(-1) x min(-1)) or glucose (10 mg x kg(-1) x min(-1)) during low-intensity leg exercise. Respiratory calorimetry was used to evaluate mitochondrial substrate oxidation. The concentration and rate of appearance of plasma lactate (from dilution of [1-(13)C]lactate) were used to evaluate glycolytic carbohydrate metabolism. (31)P magnetic resonance spectroscopy was used to determine ratios of phosphocreatine to inorganic o-phosphate in forearm muscle during exercise.


RESULTS
In 3 patients, leg exercise endurance time was better during the triacylglycerol infusion than during the glucose infusion. In all 4 patients, whole-body oxygen consumption rates during exercise were higher during triacylglycerol infusion than during the glucose infusion. In 3 patients, the concentration and rate of appearance of plasma lactate were lower during triacylglycerol infusion than during the glucose infusion. Ratios of phosphocreatine to inorganic o-phosphate during exercise were not significantly different between the 2 infusion studies or between the patients and control subjects.


CONCLUSIONS
Triacylglycerol infusion is associated with a greater oxidation of substrates, lower rates of appearance and concentrations of plasma lactate, and greater leg exercise endurance time in myopathic CID patients than is glucose infusion. The energy state of muscle during exercise, however, was not significantly different after infusion of triacylglycerol or glucose.
Roef
Mark J
MJ
Department of Pediatric Gastroenterology, the University Children's Hospital, Utrecht, Netherlands.
de Meer
Kees
K
Reijngoud
Dirk-Jan
DJ
Straver
Helma W H C
HW
de Barse
Martina
M
Kalhan
Satish C
SC
Berger
Ruud
R
D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D042967:Electron Transport Complex I; D015444:Exercise; D005260:Female; D005947:Glucose / Q000008:administration & dosage / Q000627:therapeutic use*; D006801:Humans; D007262:Infusions, Intravenous; D007773:Lactates / Q000097:blood; D009682:Magnetic Resonance Spectroscopy; D017240:Mitochondrial Myopathies / Q000209:etiology* / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases / Q000172:deficiency* / Q000378:metabolism; D010101:Oxygen Consumption; D010807:Physical Endurance / Q000187:drug effects*; D014280:Triglycerides / Q000008:administration & dosage / Q000627:therapeutic use*
D007773:Lactates; D014280:Triglycerides; D009247:NADH, NADPH Oxidoreductases; D042967:Electron Transport Complex I; D005947:Glucose