Patients suffering from the metabolic myopathy Glycogen Storage Disease type IIIa (GSDIIIa) have a problem releasing sugar stored in cells that is needed for energy production. This causes several systemic impairments, but only recently have the exercise-related symptoms in the muscles been examined. A previous study showed signs that intravenous infusion of glucose relieves some of these symptoms. The purpose of this study is to investigate in a randomized and placebo-controlled fashion whether oral ingestion of sugar can alleviate muscular symptoms in patients with GSDIIIa.
It has recently been documented how patients with GSDIIIa have a moderate to severely reduced exercise capacity, and that exercise induces muscle pain and cramps. These symptoms are caused by the inability to mobilize skeletal muscle glycogen and are most likely the consequence of a severe energy deficiency within muscles. The study changed the phenotype of GSDIIIa, to include exercise-induced symptoms, which is a typical presentation in other metabolic myopathies. It also documented that exercise capacity was significantly improved while exercise-induced muscular symptoms were relieved by an intravenous glucose infusion. Based on these findings, this study wishes to investigate if oral ingestion of sucrose has the same effects on work capacity on a larger number of patients, in a randomized, placebo-controlled, cross-over setup. Ingestion of sucrose has the potential to be an effective, cheap and easily accessible dietary treatment of muscular symptoms in GSDIIIa.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
QUADRUPLE
Enrollment
6
Sucrose and glucose containing softdrink
Diet softdrink with artificial sweeteners aspartame and acesulfame potassium. Both sweeteners are approved for use as food additives in the European Union and by the FDA. Aspartame metabolism is well understood and normal doses does not affect plasma concentrations of lipids, amino acids, glucose levels, key regulatory hormones or skeletal muscle metabolism. Acesulfame Potassium is not metabolized in humans and is excreted as the parent compound in urine. Since the two artificial sweeteners does not affect skeletal muscle metabolism or blood glucose levels, and both compounds have a well documented safety profiles, FAXE Kondi Free is considered to be an ideal placebo soft drink in this study.
Copenhagen Neuromuscular Center, department 3342, Rigshospitalet
Copenhagen, Capital Region, Denmark
maximal work capacity
Area Under the Curve (AUC) = resistance times duration of workout
Time frame: After up to 1 hour of bicycling on the 2nd and 4th day.
Peak oxygen consumption
(VO2peak)
Time frame: After up to 1 hour of cycling on the 2nd and 4th day.
Peak workload
(Wpeak)
Time frame: After up to 1 hour of cycling on the 2nd and 4th day.
Peak respiratory exchange ratio
(RER)
Time frame: After up to 1 hour of cycling on the 2nd and 4th day.
p-lactate
Analysis of blood sample
Time frame: measured at rest and max on day 1, and before first dose of soft drink, before exercise and every 10 minutes during exercise at day 2 and 4.
Heart rate
pulsemonitoring
Time frame: Continously during the cycle test (max. 1 hour) on the 2nd and 4th day
Borg score
Rate of percieved exertion
Time frame: Measured periodically during the cycle test (max. 1 hour) on the 2nd and 4th day
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