Exploring Sympathetic Nervous System Function in Individuals With Down Syndrome
Trial statusRecruiting
Trial phasePhase 3
Trial typeInterventional
Biological sexAll
Age18-50
SponsorUniversity of Colorado, Denver
About this trial
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.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
18-50 yrs old and apparently healthy individuals
Ability to understand the study and give assent to participate
Has a study partner who can attend all visits for the individuals with DS, and answer questionnaires, provide consent when necessary
Corrected or non-existent congenital heart disease
Disqualifiers
Hypertension (resting systolic blood pressure [SBP] ≥140 and/or diastolic blood pressure [DBP] ≥90 mmHg) this includes those on medications to treat hypertension
Hypotension (resting BP of <90/60 mmHg)
Cancer in the last six months
Any heart-rate-altering medications or any other medication that may modify metabolic responses
Trial design
Design model
Parallel
Treatments tested in this trial
Fear Response
Other interventionFear 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 interventionCold 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 interventionPain 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 interventionCaffeine 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 interventionFasting-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 interventionThe 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.
Treatment groups
200 Participants
are divided into 2 treatment groupsGroup A: Individuals with Down syndromeExperimental treatment 6 interventions
Group B: Individuals without Down syndromeExperimental treatment 6 interventions
Trial outcomes
Primary outcomes
1
Seated Baseline Concentration of Plasma Catecholamines
Investigators will use metabolomic techniques to quantify plasma concentrations of epinephrine, norepinephrine, and dopamine in all participants before, during (in some stressors), and after the six stressor tests. These metabolites will provide insight into sympathetic nervous system activation in individuals with Down syndrome compared to those without Down syndrome.
Time frame
Seated baseline blood draw, prior to stressors2
Concentration of Plasma Catecholamines During Cold Pressor Test
Investigators will use metabolomic techniques to quantify plasma concentrations of epinephrine, norepinephrine, and dopamine in all participants before, during (in some stressors), and after the six stressor tests. These metabolites will provide insight into sympathetic nervous system activation in individuals with Down syndrome compared to those without Down syndrome.
Time frame
During the cold stress test, around or up to 5 minutes3
Baseline Standing Concentration of Plasma Catecholamines
Investigators will use metabolomic techniques to quantify plasma concentrations of epinephrine, norepinephrine, and dopamine in all participants before, during (in some stressors), and after the six stressor tests. These metabolites will provide insight into sympathetic nervous system activation in individuals with Down syndrome compared to those without Down syndrome.
Time frame
Standing baseline blood draws, prior to fear simulation4
First Fear Simulation, Concentration of Plasma Catecholamines
Investigators will use metabolomic techniques to quantify plasma concentrations of epinephrine, norepinephrine, and dopamine in all participants before, during (in some stressors), and after the six stressor tests. These metabolites will provide insight into sympathetic nervous system activation in individuals with Down syndrome compared to those without Down syndrome.
Time frame
During the first virtual reality fear stressor, around 5 minutesSecondary outcomes
1
Facial Affective Scale Score, Baseline Assessment
Investigators will use the validated 'Facial Affective Scale', which uses a series of nine drawn faces showing various degrees of emotional distress to help participants assess their emotional state. The nine faces represent a range of negative to positive affect, and each face having a specific value between 0.04 (maximum positive affect) and 0.97 (maximum negative affect). The chosen face's corresponding value is the Facial Affective Score. This will take up to or around approximately 5 minutes to complete.
Time frame
Baseline Assessment of Facial Affective Scale, this will occur prior to any stressors.2
Facial Affective Scale Score, Cold Pressor Test, 1.5 Minutes
Investigators will use the validated 'Facial Affective Scale', which uses a series of nine drawn faces showing various degrees of emotional distress to help participants assess their emotional state. The nine faces represent a range of negative to positive affect, and each face having a specific value between 0.04 (maximum positive affect) and 0.97 (maximum negative affect). The chosen face's corresponding value is the Facial Affective Score.
Time frame
Assessment occurs around or up to 90 seconds (1.5 minutes) into cold water immersion3
Facial Affective Scale Score, Cold Pressor Test, Finale
Investigators will use the validated 'Facial Affective Scale', which uses a series of nine drawn faces showing various degrees of emotional distress to help participants assess their emotional state. The nine faces represent a range of negative to positive affect, and each face having a specific value between 0.04 (maximum positive affect) and 0.97 (maximum negative affect). The chosen face's corresponding value is the Facial Affective Score.
Time frame
Assessment occurs immediately following or during the last minute of the Cold Pressor Test, up to or around 6 minutes following placement of arm into cold4
Facial Affective Scale Score, During Pain Response, 1-Minute
Investigators will use the validated 'Facial Affective Scale', which uses a series of nine drawn faces showing various degrees of emotional distress to help participants assess their emotional state. The nine faces represent a range of negative to positive affect, and each face having a specific value between 0.04 (maximum positive affect) and 0.97 (maximum negative affect). The chosen face's corresponding value is the Facial Affective Score.
Time frame
Assessment will take place approximately 1-minute following administration of the pain patchSponsors and contacts
Click on the lead sponsor to view all of their trials.
University of Colorado, Denver
Lead sponsor
National Institute on Aging (NIA)
Collaborator
Linda Crnic Institute for Down Syndrome
Collaborator
GLOBAL Down Syndrome Foundation
Collaborator
University of Colorado Colorado Clinical and Translational Sciences Institute
Collaborator
Source ClinicalTrials.gov