Leucine-enriched Essential Amino Acid Intake to Optimize Protein Anabolism in Children With Cystic Fibrosis

In this study, we will test the following hypothesis: A high-leucine essential amino acid mixture (dose of 6.7 g) will stimulate protein anabolism to a greater extent than a standard balanced mixture of total (essential and non-essential) amino acids in CF pediatric subjects. The principal endpoints will be the extent of stimulation of protein synthesis rate and the reduction in endogenous protein breakdown. The current project will provide information that will enable us to better understand the underlying metabolic mechanisms that regulate protein metabolism in pediatric subjects with CF.

Inclusion criteria

• Subjects who already have a diagnosis of CF based on universal diagnostic criteria.
• Age 14 to 21 years at the time of enrollment
• Under routine medical control at the CF center of ACH
• Admitted to the ACH for treatment of pulmonary exacerbation of CF disease.
• Improvement in lung function (FEV1) at the time of enrollment back to baseline values (as determined in the clinically stable pre-hospital period)
• Central or peripheral venous line in place
• No planned major changes or interventions in the treatment and care of the pediatric subject on Day -2 and -1 before discharge from the hospital.

Exclusion criteria

• Established diagnosis of Diabetes Mellitus
• Presence of fever within the last 3 days
• Unstable metabolic diseases including liver (cirrhosis) or renal disease
• Chronic respiratory failure with cor pulmonale
• Use of long-term oral corticosteroids or short course of oral corticosteroids in the preceding month before enrollment
• Any other condition according to the principle investigator or study physician would interfere with collecting study samples
• Failure to give assent / informed consent