Exploring Sympathetic Nervous System Function in Individuals With Down Syndrome

Part of paid clinical trials in Aurora, Colorado.

Sponsor
University of Colorado, Denver
Study ID
NCT07238465
Phase
PHASE3
Status
Recruiting
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Conditions

  • Autonomic Dysfunction
  • Down Syndrome

Eligibility Criteria

Sex
ALL
Age
18 Years - 50 Years
Healthy Volunteers
Accepted

Interventions

  • Fear Response — OTHER
    Fear triggers the sympathetic nervous system, known as the 'fight-or-flight' response, which prepares the body to respond to a perceived threat by increasing heart rate, blood pressure, and releasing catecholamines. These measurements will be taken to examine the cardiovascular physiology of how individuals with DS will respond during a scary simulation. The investigators are looking at how plasma catecholamines (i.e., Epinephrine, Norepinephrine, and Dopamine), blood pressure, and heart rate are expressed during a fear simulation using virtual reality goggles in individuals with Down syndrome, who have proposed autonomic dysfunction. This study will compare responses among individuals with Down syndrome to a control group without Down syndrome.
  • Cold Stress — OTHER
    Cold triggers the sympathetic nervous system, known as the 'fight-or-flight' response, which prepares the body to respond to a perceived threat by increasing heart rate, blood pressure, and releasing catecholamines. These measurements will be taken to examine how individuals with DS will respond during a cold stress test. The investigators are looking at how plasma catecholamines (i.e., Epinephrine, Norepinephrine, and Dopamine), blood pressure, and heart rate are expressed during a cold stress test in individuals with Down syndrome, who have proposed autonomic dysfunction. This study will compare responses among individuals with Down syndrome to a control group without Down syndrome.
  • Pain Response — OTHER
    Pain triggers the sympathetic nervous system, known as the 'fight-or-flight' response, which prepares the body to respond to the perceived threat (i.e., hurt) by increasing heart rate, blood pressure, and releasing catecholamines. These measurements will be taken to examine how individuals with DS will respond during application of a painful patch. The investigators are looking at how plasma catecholamines (i.e., Epinephrine, Norepinephrine, and Dopamine), blood pressure, and heart rate are expressed during application of a pain patch in individuals with Down syndrome, who have proposed autonomic dysfunction. This pain patch is similar to what someone would buy at the drug store for sore muscles. This study will compare responses among individuals with Down syndrome to a control group without Down syndrome.
  • Caffeine — OTHER
    Caffeine acts as a stimulant to the sympathetic nervous system leading to an increase in blood pressure, heart rate, and release of catecholamines. The investigators are looking at how plasma catecholamines (i.e., Epinephrine, Norepinephrine, and Dopamine), blood pressure, and heart rate are expressed following ingestion of a caffeine pill (similar to \~2 cups of coffee) in individuals with Down syndrome, who have proposed autonomic dysfunction. This study will compare responses among individuals with Down syndrome to a control group without Down syndrome.
  • 12-Hour Fast — OTHER
    Fasting-induced hypoglycemia triggers a 'fight-or-flight' response as the body attempts to raise low blood glucose levels to bring them back to 'normal'. These measurements will be taken to examine how individuals with DS will respond following a 12-hour abstinence from food, inducing low blood sugar. The investigators are looking at how plasma catecholamines (i.e., Epinephrine, Norepinephrine, and Dopamine), blood pressure, and heart rate are expressed following a 12-hour fast in individuals with Down syndrome, who have proposed autonomic dysfunction. This study will compare responses among individuals with Down syndrome to a control group without Down syndrome.
  • Maximal Dynamic Exercise — OTHER
    The investigators are looking at how plasma catecholamines (i.e., Epinephrine, Norepinephrine, and Dopamine), blood pressure, and heart rate are expressed during a treadmill maximal exercise test in individuals with Down syndrome, who have proposed autonomic dysfunction. This study will compare responses among individuals with Down syndrome to a control group without Down syndrome.

Study Details

Down syndrome (DS), the most common genetic cause of intellectual disability, is associated with widespread organ dysfunction, including abnormalities in the autonomic nervous system (ANS). The ANS regulates critical functions such as heart rate (HR) and blood pressure (BP), both essential for maintaining homeostasis and supporting physical activity. Individuals with DS often exhibit blunted HR responses to exercise-typically \~30 beats per minute below expected levels-suggesting reduced sympathetic nervous system (SNS) activity. The SNS governs rapid changes in HR and BP during stress by releasing catecholamines: epinephrine (from the adrenal medulla) and norepinephrine (from sympathetic nerve endings). Despite its importance, SNS function has not been comprehensively assessed among individuals with DS. This study addresses a critical knowledge gap by evaluating SNS responses to physiological stressors in individuals with DS. The investigators will measure beat-to-beat HR and BP, along with plasma catecholamine levels, in response to sympathetic activation, comparing individuals with DS to age- and sex-matched controls. Understanding the mechanisms of SNS dysfunction in DS is vital, as it likely underlies reduced exercise capacity and contributes to broader clinical challenges. These insights may guide targeted interventions to improve cardiovascular function, physical capacity, and overall quality of life in this understudied population.

Key Dates

Start date
Apr 6, 2026
Status verified
Apr 2026
Primary completion
Dec 31, 2028
Completion
Dec 31, 2029

Study Design

Enrollment
200 participants (estimated)
Allocation
NON_RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION

Arms

  • Experimental: Individuals with Down syndrome
    The investigators will be recruiting participants between the ages of 18-50 for the study investigating responses to six sympathetic stressors compared to age and sex matched individuals without Down syndrome.
  • Experimental: Individuals without Down syndrome
    The investigators will be recruiting individuals without Down syndrome between the ages of 18-50 to serve as the comparisons for individuals with Down syndrome across the six sympathetic stressors.

Primary Outcome Measure

Seated Baseline Concentration of Plasma Catecholamines [ Time Frame: Seated baseline blood draw, prior to stressors ]

Central Contacts

Locations (1)

FacilityCityStateZIPSite coordinators
Linda Crnic Institute for Down Syndrome, University of Colorado Anschutz Medical CampusAuroraColorado80045
Joaquin M Espinosa, PhD
[email protected]
303-724-7389
Angela Rachubinski, PhD
[email protected]

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By research site
Linda Crnic Institute for Down Syndrome, University of Colorado Anschutz Medical Campus· Aurora, CO

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