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Completed

NCT Number: NCT02733120

Metabolic Processes in Adults and Adolescents With Autism Spectrum Disorder

The objective of this study is to gain preliminary information and knowledge on metabolic profile in ASD. The benefit of this study will be to expand our insight of the potential relationship in metabolic processes and neuropsychological functions in ASD. For example, based on the obtained data of the study we can determine whether there is a link between the tryptophan pathway and cognitive functions in autism. The project is based on a systematic and multidisciplinary approach using tracers for delineating the mechanism by which the metabolism of amino acids like TRP is involved in affective and cognitive functions in ASD. Using an innovative approach to the evaluation of amino acids has not been used in adults with ASD. In addition, the obtained data of the study holds promise to develop specific markers (metabolic and/or neuropsychological) for guiding the identification those individuals with increased risk of developing mood disturbances or cognitive impairment, and for predicting the therapeutic effect of a specific nutritional interventions in subjects with ASD.

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Key information

Conditions

Autism Spectrum Disorder Child Development Disorders, Pervasive Mental Disorders Neurodevelopmental Disorders

Age range

16 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Texas A&M University-CTRAL

College Station, Texas, 77843, United States

About this study

This study investigates the metabolic profile of different amino acids and cognitive functions in adults and adolescents with ASD in comparison with age- and gender-matched healthy young adults. The study involves 1 screening visit of approximately 2 hours and 1 study day of 5 hours

The objective is to explore changes in amino acids (e.g. TRP pathway) in ASD and evaluate the function of TRP in neuropsychological functions by using the technique of stable isotope and our newly developed 'single pulse method' with multiple amino acid and keto-acid isotopes.

The aim of this study is to determine the underlying mechanism by which the metabolism of amino acids such as TRP are involved in mood and cognitive functions in ADS.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Healthy:

  • Healthy male or female according to the investigator's or appointed staff's judgment
  • Age 16 years or older
  • Ability to walk, sit down and stand up independently
  • Ability to lie in supine or elevated position for 4 hours
  • Willingness and ability to comply with the protocol

Inclusion criteria

subjects with Autism Spectrum Disorder (ASD):

  • Healthy high functioning person diagnosed with autism spectrum disorder
  • Age 16 years or older
  • Ability to walk, sit down and stand up independently
  • Ability to lie in supine or elevated position for 4 hours
  • Willingness and ability to comply with the protocol

Exclusion criteria

  • Any condition that may interfere with the definition 'healthy subject' according to the investigator's judgment (for healthy group)
  • Failure to give informed consent
  • Established diagnosis of Insulin Dependent Diabetes Mellitus
  • Metabolic diseases, including hepatic or renal disorders
  • Presence of acute illness or metabolically unstable chronic illness
  • Presence of fever within the last 3 days
  • Pre-planned surgery of procedures that would interfere with the conduct of the study
  • Any other condition according to the PI or study physician that would interfere with proper conduct of the study / safety of the patient
  • Current alcohol or drug abuse
  • Use of protein or amino acid containing nutritional supplements within 5 days prior to the study days
  • Use of long-term oral corticosteroids or short course of oral cortico-steroids 4 weeks preceding first test day
  • Body Mass Index of < 18.5 or ≥ 40 kg/m2
  • Montreal Cognitive Assessment score of < 20

Treatment and study plan

stable isotope infusion

Other

stable isotopes such as 15N2, TRP, 2H3-Leucine, L-[2H3]-3-Methylhistidine, 2H2-Glycine, 2-D-hydroxyproline, 1-13C-ketoisocaproic acid (KIC), L-[Guanido-15N2]-Arginine, L-[ureido-13C-2H2]-Citrulline), L-Glutamine-amide-15N, 1,2-13C2-L-Glutamic acid, 1,2-13C2Taurine, and 13C-Urea is given IV simultaneously

Primary outcomes

  1. Tryptophan turnover

    Time frame: 2, 5, 10, 15, 20, 30, 40, 50, 60, 90, 120, 150, 180, 210 and 240 ± 5 minutes

Secondary outcomes

  1. leucine turnover

    Time frame: 2, 5, 10, 15, 20, 30, 40, 50, 60, 90, 120, 150, 180, 210 and 240 ± 5 minutes

  2. Whole body myofibrillar protein breakdown rate (reflecting muscle protein breakdown)

    Time frame: 2, 5, 10, 15, 20, 30, 40, 50, 60, 90, 120, 150, 180, 210 and 240 ± 5 minutes

  3. glutathione turnover

    Time frame: 2, 5, 10, 15, 20, 30, 40, 50, 60, 90, 120, 150, 180, 210 and 240 ± 5 minutes

  4. hydroxyproline breakdown (reflecting collagen breakdown)

    Time frame: 2, 5, 10, 15, 20, 30, 40, 50, 60, 90, 120, 150, 180, 210 and 240 ± 5 minutes

  5. glutamate turnover

    Time frame: 2, 5, 10, 15, 20, 30, 40, 50, 60, 90, 120, 150, 180, 210 and 240 ± 5 minutes

  6. taurine turnover

    Time frame: 2, 5, 10, 15, 20, 30, 40, 50, 60, 90, 120, 150, 180, 210 and 240 ± 5 minutes

  7. urea production

    Time frame: 2, 5, 10, 15, 20, 30, 40, 50, 60, 90, 120, 150, 180, 210 and 240 ± 5 minutes

  8. Group differences in state of mood as measured by the Hospital Anxiety and Depression Scale (HADS),

    Time frame: 1 day

    a fourteen item self-assessment scale. Seven of the items related to anxiety and seven relate to depression. Each item on the questionnaire is scored from 0-3 and this means that a person can score between 0 (no symptoms) and 21 (severe symptoms) for either anxiety or depression.

  9. Group differences in learning and memory as measured by Auditory Verbal Learning Test (AVLT)

    Time frame: 1 day

    Auditory Verbal Learning Test (AVLT): a verbal episodic memory test that evaluates a wide diversity of functions: short-term auditory-verbal memory, rate of learning, retention and recognition of information.

  10. Group differences in learning and memory as measured by Controlled Oral Word Association Test (COWAT),

    Time frame: 1 day

    ontrolled Oral Word Association Test (COWAT): The examinee is required to say as many words as they can think of in one minute that begin with a given letter of the alphabet. The task contains three trials. Measures phonetic verbal fluency. The raw score (total and mean words recorded across the three trials) was reported.

  11. Group differences in learning and memory as measured by Digit Span

    Time frame: 1 day

    recall of numbers in the same order (Digit Forward) and in reverse order (Digit Backward). Measures auditory attention and verbal working memory.

  12. Group differences in overall cognitive abilities as measured by Montreal Cognitive Assessment (MoCA)

    Time frame: 1 day

    assesses several cognitive domains and is used for the screening of mild cognitive impairment. Total scores range from 0-30 with lower scores indicating decreased functioning.

  13. Group differences in attention and executive functions as measured by Trail Making Test (TMT),

    Time frame: 1 day

    In Part A, the examinee is instructed to connect a set of 25 circles with numbers as quickly as possible while maintaining accuracy. In Part B, the examinee is instructed to connect a set of 25 circles, alternating between numbers and letters, as quickly as possible while maintaining accuracy. Measures attentional resources and is a measure of the frontal lobe "executive" functions of visual search, set-switching and mental flexibility. The total time in seconds was reported for each measure.

  14. Group differences in attention and executive functions as measured by Stroop Color-Word Test (SCWT),

    Time frame: 1 day

    a word page with words printed in black ink, a color page with blocks printed in color, and a color-word page where the color and the word do not match. The examinee reads the words or names the ink colors as quickly as possible within a time limit. Measures selective attention and inhibitory control. The total time in seconds was reported for each trial.

  15. Adolescent/Adult Sensory Profile

    Time frame: 1 day

    a standardized self-questionnaire that generates an individualized profile of sensory processing across four quadrants: low registration, sensation seeking, sensory sensitivity, and sensation avoiding.

  16. Group differences in attention and executive functions as measured by Brief-A

    Time frame: 1 day

    a standardized self-report that captures views of an adult's executive functions or self-regulation in his or her everyday environment.

  17. Group differences in attention and executive functions as measured by PASAT

    Time frame: 1 day

    a measure of cognitive function that assesses auditory information processing speed and flexibility, as well as calculation ability.

Sponsors and collaborators

Lead sponsor

Texas A&M University

Other

Registry information

Official study title

Study on Metabolic Processes and Cognitive Functions in Adults and Adolescents With Autism Spectrum Disorder

Acronym: ASD

Important dates

Study start
2015
Primary completion
2017
Study completion
2017
First posted
Apr 11, 2016
Registry last updated
Sep 30, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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