Development of Oral Amino Acid Tracers to Study Protein Turnover in Humans

Healthy Adult Males Clinical Trial

Official title:

Development of Oral Amino Acid Tracers to Study Protein Turnover in Humans

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT04887727
• Other study ID #: Connaught
• Status: Completed
• Phase: N/A
• Start date: February 25, 2019
• Est. completion date: August 31, 2019

Study information

• Verified date: May 2021
• Source: University of Toronto
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

Previous studies have used a combination of oral L-[1-13C]leucine and intravenous labeled L-[5,5,5-2H3]leucine to assess the acute postprandial changes in whole-body protein turnover (12, 19). Intravenous and dietary-labeled amino acid tracers have also been used in tandem to assess rates of myofibrillar protein synthesis in response to bolus protein ingestion and resistance exercise (46). By validating whole-body net balance to myofibrillar protein synthesis, our proposed multi-tracer approach will develop minimally invasive models to study protein turnover in a variety of populations in which traditional infusions and/or repeated blood samples are not possible (i.e. pediatric, free-living populations).

Description:

The primary objective of the proposed study is to validate the use of a novel oral tracer model to accurately and reliably measure myofibrillar protein synthesis. It is hypothesized that oral L-[1-13C]leucine and L-[ring-2H5]phenylalanine, ingested as a bolus to mimic an intravenous 'pulse dose' administration (51, 65), will reveal similar rates of myofibrillar protein synthesis when compared to traditional intravenous L-[5,5,5-2H3]leucine infusion. Moreover, it is hypothesized that both methods will reveal the expected graded changes in myofibrillar protein synthesis in response to feeding and resistance exercise (i.e. fasted

Recruitment information / eligibility

• Status: Completed
• Enrollment: 22
• Est. completion date: August 31, 2019
• Est. primary completion date: August 31, 2019
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Male
• Age group: 18 Years to 35 Years

Eligibility

Inclusion Criteria:

• Male
• Currently performing structured physical activity 2-5 days per week

Exclusion Criteria:

• Unable to safely perform exercise as per PARQ+ guidelines
• Currently using tobacco products
• Currently using or have history of anabolic steroid use
• Diagnosed with medical condition including type 2 diabetes, cancer, heart disease
• Unable to abstain from supplement use (HMB, branched chain amino acids, phosphatidic acid) for at least three weeks prior to trial
• currently using medications known to affect protein metabolism e.g. corticosteroids, NSAID, prescription-strength acne medication
• allergic to local anesthetics
• female: Hormonal fluctuations associated with the menstrual cycle have been reported to alter protein metabolism during exercise and may influence indices of the post-exercise myofibrillar protein synthetic response. Accordingly, the study will include males to ensure a stable hormonal environment and to increase the homogeneity of the physiological response.

Related Conditions & MeSH terms

• Healthy Adult Males

Intervention

Dietary Supplement:
• Crystalline amino acids to assess myofibrillar protein synthesis rates
Amino acid dose = 0.25g/kg bodyweight
• Crystalline amino acids to assess whole-body protein turnover, amino acid oxidation, and net protein balance
Amino acid dose = 0.25g/kg bodyweight

Locations

Country	Name	City	State
Canada	Goldring Centre for High Performance Sport at the University of Toronto	Toronto	Ontario

Sponsors (1)

Lead Sponsor	Collaborator
University of Toronto

Country where clinical trial is conducted

Canada, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Myofibrillar protein synthesis rates	Myofibrillar protein synthesis rates assessed by oral and intravenous tracers during Fast, Fed, and Ex-Fed	5 hours
Secondary	Whole-body protein turnover	Whole-body protein turnover assessed by oral and intravenous tracers during Fast, Fed, and Ex-Fed	5 hours
Secondary	Amino acid oxidation and net protein balance	Amino acid oxidation and net protein balance assessed by oral tracers during Fast, Fed, and Ex-Fed. Net protein balance is derived from the difference between amino acid intake (known) and total amino acid oxidation over the 5h measurement period.	5 hours
Secondary	Muscle anabolic signalling	Immunoblotting for mTORC1/key downstream targets of mTORC1	2 and 5 hours
Secondary	Amino acid transporter expression	Immunoblotting for amino acid transporters LAT1/SNAT2	2 and 5 hours