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Fat and Sugar Metabolism During Exercise, With and Without L-carnitine in Patients With Carnitine Transporter Deficiency (CTD)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT02226419
Recruitment Status : Completed
First Posted : August 27, 2014
Last Update Posted : May 5, 2015
Rigshospitalet, Denmark
Information provided by (Responsible Party):
Karen Lindhardt Madsen, Rigshospitalet, Denmark

Brief Summary:

The investigators wish to investigate fat and sugar metabolism during exercise with and without L-carnitine supplementation in patients with carnitine transporter deficiency (CTD).

Patients with CTD have low plasma- and muscle concentrations of carnitine, which is believed to lead to an impaired fat oxidation. Presently there is no cure available for these patients, but daily intake of L-carnitine has been shown to limit the amount of symptoms. Little is known about the metabolism during exercise and the pathophysiological mechanisms causing the symptoms.

Studying the fat and sugar metabolism in CTD patients will contribute to the understanding of the role of the carnitine transporter in the development of symptoms in these patients. Furthermore, knowledge about the fat and sugar metabolism in these patients can increase the understanding of the role of the carnitine transporter in the metabolism healthy persons.

The investigators have included 8 patients with genetically verified CTD in the study and a group of 10 age- and sex-matched controls. Subjects will perform a 1h cycling test, exercising at a moderate intensity. By measuring the expiration of carbon dioxide (CO2) and consumption of oxygen (O2), the investigators can determine the total fatty acid and carbohydrate oxidation during cycling. At the same time the investigators will measure the patients' whole body palmitate (fat) and glucose (sugar) oxidation rates using stable isotope technique.

The patient group will repeat the cycling test after 4 days without taking their usual L-carnitine treatment. During the treatment break, patients will be admitted to be continuously monitored for heart rhythm disturbances, which is a known but rarely occurring complication to untreated CTD.

Since the patients have a defect in their fat metabolism, the investigators expect to find that they have a reduced ability to burn fat, which is the major source of energy during low intensity exercise. It is therefore likely, that the CTD patients will benefit from adjustments in their daily diet, whenever they have to perform physically. By learning about the metabolism of different dietary substances, fat and sugar, these studies can help to improve the treatment in terms of dietary recommendations for CTD patients. This will have a direct impact on the daily life of the patients.

Condition or disease Intervention/treatment Phase
Carnitine Transporter, Plasma-membrane, Deficiency of Dietary Supplement: Break in L-carnitine treatment Not Applicable

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 14 participants
Allocation: N/A
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Fat and Carbohydrate Metabolism During Exercise, With and Without L-carnitine Supplementation in Patients With Carnitine Transporter Deficiency
Study Start Date : August 2013
Actual Primary Completion Date : August 2014
Actual Study Completion Date : August 2014

Arm Intervention/treatment
Experimental: Break in L-carnitine treatment
Patients do not take their L-carnitine (Levocarnitine) treatment for 2-4 days until plasma carnitine and acylcarnitine have fallen. While patients abstain from taking the treatment, they are admitted for cardiac telemetry monitoring.
Dietary Supplement: Break in L-carnitine treatment
Levocarnitine oral tablet supplement at individual doses
Other Name: Levocarnitine

Primary Outcome Measures :
  1. The whole body palmitate and carbohydrate oxidation rate in CTD patients during exercise [ Time Frame: With and without L-carnitine treatment ]
    The whole body palmitate and carbohydrate oxidation will be assessed during 1h exercise test performed on a cycle-ergometer using stable isotope technique combined with indirect calorimetry.

Secondary Outcome Measures :
  1. The maximal oxidative capacity (VO2max) as an indicator of exercise tolerance and performance in CTD patients [ Time Frame: During a 15 min incremental intensity exercise test and during a 1h moderate intensity cycling test ]

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Verified diagnosis of CTD

Exclusion Criteria:

  • Other conditions or diseases that may compromise the outcome of the study
  • Pregnancy or lactation
  • Inability to cooperate carrying out the experiments

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT02226419

Sponsors and Collaborators
Karen Lindhardt Madsen
Rigshospitalet, Denmark
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Principal Investigator: Karen L Madsen, MD Neuromuscular Research Unit, Rigshospitalet
Publications automatically indexed to this study by Identifier (NCT Number):
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Responsible Party: Karen Lindhardt Madsen, MD, Rigshospitalet, Denmark Identifier: NCT02226419    
Other Study ID Numbers: H-1-2012-130
First Posted: August 27, 2014    Key Record Dates
Last Update Posted: May 5, 2015
Last Verified: May 2015
Keywords provided by Karen Lindhardt Madsen, Rigshospitalet, Denmark:
Fatty acid oxidation disorder
Primary carnitine deficiency
L-carnitine treatment
Stable isotopes
Carnitine transporter deficiency