Randomized, placebo-controlled trial with a 2x2 factorial design testing the effects of an NAD+ precursor (NR) and exercise on VO2max and Si in Friedreich's Ataxia (FA). The primary objective of this research is to measure the effect of combination administration (NR + exercise) on aerobic capacity (VO2max) in FA. A key secondary objective is to measure the effect of combination administration (NR + exercise) on glucose homeostasis (Si) in FA.
Friedreich's Ataxia (FA) is a progressive neurodegenerative disease affecting 1 in 50,000 individuals in the U.S. Currently, there is no approved treatment. There is a critical knowledge gap regarding the best ways to intervene to increase aerobic capacity (VO2max on exercise testing) in FA. Exercise is the most potent known stimulus for increasing muscle mass and mitochondrial oxidative phosphorylation (OXPHOS) capacity, increasing VO2max, and increasing insulin sensitivity (Si), however, it has not been studied in FA. One adaptation seen in exercised muscles is an increase in muscle nicotinamide adenine dinucleotide (NAD+), a cofactor required for glycolytic and mitochondrial adenosine triphosphate (ATP) production. In skeletal- and cardiac muscle-specific frataxin (FXN) knock-out animals, NAD+ precursors rescued cardiac function to near-normal, additionally highlighting its translational potential in FA. Nicotinamide riboside (NR) is a NAD+ precursor currently available as a dietary supplement (Tru Niagen ®, ChromaDex, Irvine CA) that is expected to be safe and well-tolerated in adults and children. The central hypothesis is that exercise + NR will increase skeletal muscle mitochondrial OXPHOS and increase muscle mass to increase VO2max in FA. The investigators expect that exercise + NR will also increase Si in this cohort.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
QUADRUPLE
Enrollment
80
Investigators will use (Good Manufacturing Process) GMP-grade 300 mg capsules of the dietary supplement nicotinamide riboside (ChromaDex, Irvine CA). NR is distributed by ChromaDex, Inc., Irvine, CA. NR is available as 300 mg capsules. The dietary supplement will be re-labeled by the Hospital of the University of Pennsylvania (HUP) Investigational Drug Service according to FDA regulations, including subject and physician name and NR or Placebo 300 mg capsules.
The matched placebo will contain the same excipients without the active supplement and is generally recognized as safe. The placebo will be covered in an identical capsule (NR will be covered in the same capsule).
Children's Hospital of Philadelphia
Philadelphia, Pennsylvania, United States
Within-Participant Change in V02 Max (Maximal Oxygen Uptake on Cardiopulmonary Exercise Testing)
V02 Max will be assessed by completion of an incremental symptom-limited cardio-pulmonary Exercise Stress Test (EST) on a recumbent leg cycle ergometer.
Time frame: Baseline to 12 Weeks
Within-Participant Change in Whole Body Insulin Sensitivity (Si)
Whole Body Insulin Sensitivity (Si) will be assessed by completion of a stable isotope tracer-enhanced Oral Glucose Tolerance Test (OGTT). Samples will be collected at 10 time points for analysis.
Time frame: Baseline to 12 Weeks
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The exercise program consists of at-home training sessions: 3 aerobic sessions per week on the in-home bike trainer, and 2 resistance exercise sessions per week using resistance bands. On aerobic training days, subjects will be given instruction on a recumbent Catrike trainer, titrated such that they spend 20 minutes at their target heart rate as determined by baseline Exercise Stress Test (EST) (60-80% of their heart rate at peak VO2) and as measured by their wearable device. On resistance training days, subjects will be given instructions to complete circuits of resistance exercises. Resistance training intensity (as determined by graded resistance bands) will be maintained at 60% of pre-training maximal voluntary contraction for each muscle group.