Validating IAAO for Muscle Outcomes (VIM)

University of Toronto

Status: Enrolling

Conditions: Protein Metabolism

Treatments: Dietary Supplement: Protein + Stable Isotope Tracer Beverage

Study type: Interventional

Funder types: Other

Identifiers

NCT07317921

VIM

Details and patient eligibility

About

Consuming dietary protein stimulates whole-body and muscle protein synthesis, the latter of which is typically measured using invasive primed constant infusions of stable isotopes with concurrent muscle biopsies. Alternative non-invasive methodologies have been developed (namely the indicator amino acid oxidation (IAAO) technique) to estimate the impact of protein ingestion on whole-body protein synthesis as a proxy for determining dietary protein requirements. Given that the IAAO technique is based on principles of protein metabolism which occur in the liver, it is unclear how representative the IAAO outcomes of whole-body protein synthesis is to skeletal muscle protein synthesis. Validation of the IAAO technique against gold-standard, biopsy-derived measures of muscle metabolism (i.e., muscle protein synthesis) would assist in mitigating the invasiveness of muscle physiology and nutrition research.

Enrollment: 8 estimated patients

Sex: All

Ages: 18 to 35 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Participants will be aged 18-35 years old
• Participants will have a BMI within the normal range (i.e., 18.5-24.9) and waist-to-hip circumference ratio of <0.95 for males and <0.8 for circumference for females to ensure homogeneity of the sample population
• Participants are willing to abide by the compliance rules of this study (e.g., abstain from extraneous physical activity 48h prior to session 4
• Self-reported regular menstrual cycle (25-35d) within the last 3 months (female participants)
• Physical activity score of ≥24 units as measured by the Godin leisure time exercise questionnaire

Exclusion criteria

• Inability to adhere to any of the compliance rules judged by principal investigator
• Self-reported regular tobacco or illicit drug use (e.g., growth hormone or testosterone)
• Current use of hormonal contraceptives
• Individuals with a history of allergy to local anesthetics (e.g., lidocaine)

Trial design

Primary purpose: Basic Science

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

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8 participants in 1 patient group

Protein + Stable Isotope Tracer Beverage

Experimental group

Description:

Participants will consume 12 half-hourly (6 hours) isoenergetic, isonitrogenous beverages containing 0.9g/kg fat-free mass/day protein. Drinks will be enriched with stable isotopes \[2H5\]Phenylalanine and \[1-13C\]Phenylalanine, which will respectively allow for determination of muscle protein synthesis and whole-body protein synthesis over the subsequent 6 hours of feeding.

Treatment:

Dietary Supplement: Protein + Stable Isotope Tracer Beverage