Tryptophan Metabolism in Healthy Young Adults

NCT06551545 | Completed

• 1 other identifier: 1000081438
• Study Type: interventional
• Target: 10
• Locations: 1 country
• Sites: 1

Brief Summary

Tryptophan is an essential amino acid needed for growth and bodily functions. It is used to make serotonin which is needed for the brain to develop and function properly. However, when the body is stressed, tryptophan is broken down into compounds that can cause harm to the brain. Premature babies who get nutrition through their vein \[i.e. total parenteral nutrition (TPN)\] can experience this type of stress. The amount of tryptophan in TPN solutions is much higher than what premature babies need and can produce too much harmful compounds. So, it is important to study the amount of these compounds made from tryptophan. But there are no methods available to study this. Therefore, the goal of this study is to develop a method to measure the compounds made from tryptophan breakdown in adults so that it can be used for preterm babies on TPN later.

Conditions

Healthy

Keywords

adults; healthy; tryptophan; tryptophan breakdown; indicator amino acid oxidation; stable isotope

Outcome Measures

Primary Outcomes (2)

• Fractional Synthesis Rate (FSR) of tryptophan metabolites

  Enrichment of L-\[15N2\]tryptophan and its metabolites (15N2-L-kynurenine, 15N-kynurenic acid, 15N-quinolinic acid, 15N2-serotonin and 15N-5-hydroxyindole acetic acid) in plasma and urine following orally administered tracer, L-\[15N2\]tryptophan.

  10 hours

• Steady state

  Time at which plasma and urine enrichment of L-\[15N2\]tryptophan reaches steady-state.

  10 hours

Secondary Outcomes (2)

• Partitioning of tryptophan metabolism

  10 hours

• Fractional synthesis rate (FSR)

  10 hours

Study Arms (1)

Experimental: Tryptophan in healthy young adults (18-45 years)

EXPERIMENTAL

Tryptophan intake levels, up to 5 levels, will be tested in a random order in all subjects

Dietary Supplement: Tryptophan intake

Interventions

Tryptophan intake DIETARY_SUPPLEMENT

There are 5 different tryptophan test intake levels ranging from 2, 3, 4.5, 6, 8 mg.kg-1.day.1

Experimental: Tryptophan in healthy young adults (18-45 years)

Eligibility Criteria

• Age: 18 Years - 45 Years
• Sex: male
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Consent provided
• Aged 18 to 45 years old (inclusive)
• In good general health as evidenced by medical history, physical health and biochemistry
• Fasting blood glucose, hemoglobin A1c (HbA1c), urea, creatinine and CRP levels within normal ranges for age.

You may not qualify if:

• Presence of chronic disease and/or acute illness known to affect protein/amino acid metabolism (e.g. HIV, diabetes, cancer, liver or kidney disease, neurological conditions including depression and anxiety, hypo- / hyperthyroidism, inflammatory conditions,, anemia, acute cold or flu)
• Taking medications known to affect protein/AA metabolism (e.g. steroids, anti-inflammatory medications, acetaminophen, selective serotonin reuptake inhibitors (SSRI))
• Inability to tolerate the diet (i.e. allergy)
• Significant weight loss during the past month or consumption of weight reducing diets.
• Significant caffeine consumption (\>2 cups per day)
• Significant consumption of alcohol (\>1 drink per day i.e. 1 beer or ½ glass of wine).
• Unwilling to have blood drawn from a venous access or using a ventilated hood indirect calorimeter for the purposes of the study.

Sponsors & Collaborators

• The Hospital for Sick Children: lead
• Canadian Institutes of Health Research (CIHR): collaborator

Study Sites (1)

The Hospital for Sick Children

Toronto, Ontario, M5G 1E8, Canada

Location

Study Officials

• Glenda Courtney-Martin, PhD, RD

  The Hospital for Sick Children

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal investigator

Study Record Dates

• First Submitted: August 8, 2024
• First Posted: August 13, 2024
• Study Start: January 1, 2025
• Primary Completion: July 31, 2025
• Study Completion: July 31, 2025
• Last Updated: March 30, 2026

Record last verified: 2025-05

Locations

CA (1)