Acute Plasma Abeta Responses to Stress

Study Overview
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Brief Summary
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Research has shown that activation of the sympathetic nervous system for extended periods or during certain times in life can increase the risk for Alzheimer's disease. Some research in animal models show that acute activation of the sympathetic nervous system through stress exposure can increase certain Alzheimer's disease-related biomarkers, such as amyloid-beta, within hours of exposure. However, how acute sympathetic nervous system activation via stress exposure affects amyloid-beta levels in humans has yet to be examined. In this study, the investigators will examine whether brief increases in sympathetic activation result in immediate changes in plasma amyloid-beta levels in the five hours after exposure.

Detailed Description
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Aim 1: determine whether acute exposure to stress (increasing sympathetic nervous system activation) increases plasma amyloid-beta-40 and amyloid-beta-42 in the five hours following exposure.

Official Title
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Effects of Acute Stress Exposure on Plasma Beta-amyloid Levels

Conditions
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Stress Reaction, Stress Physiology

Intervention / Treatment
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* Behavioral: Sympathetic Nervous System Activation
* Behavioral: No-stress


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy adult weighing at least 110 pounds No chronic conditions or illness Taking no medications or drugs that might alter the stress response (e.g., corticosteroids, beta-blockers, and others) Not using any hormone-containing medication (e.g., hormonal contraceptives, hormone replacement, etc.) No contraindications for cold pressor test exposure (high blood pressure, heart disease, dysrhythmia, peripheral vascular disease, any other cardiovascular disorder, diabetes, vasculitis, lupus, tingling or numbness in the hands and/or feet, cryoglobulinemia, and Reynaud's phenomenon) No history of fainting during blood draws No phobia of having their blood drawn No general history of fainting or seizures Not currently diagnosed with a mood disorder (e.g., major depressive disorder) Not pregnant in the past 12 months Not lactating in the past 12 months Not trying to become pregnant if premenopausal Experienced natural menopause if postmenopausal Be non-smokers Be fluent in English Exclusion Criteria: - Unwilling to be filmed during the stress task OR unwilling to sign the waiver allowing their filmed responses to be used in scientific presentations

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Participants will complete one session of each condition: stress and no-stress. Participants will be randomly assigned to one of the two conditions for their first session. Participants will then be randomly assigned to the remaining condition for the second session.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Stress (sympathetic nervous system activation)<br>Stress will be induced using the socially evaluated cold pressor test. Participants will complete three rounds of the socially evaluated cold pressor test. The socially evaluated cold pressor test involves submerging one hand in ice-cold water for 3 minutes while participants' reactions are filmed on camera. | Behavioral: Sympathetic Nervous System Activation<br>* Participants will complete a task that increases sympathetic nervous system activation.<br>|
| Sham Comparator: No-stress<br>Participants will hold a hand in room temperature water for 3 minutes. | Behavioral: No-stress<br>* Participants will complete a task that will not affect their sympathetic nervous system activity.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Plasma amyloid-beta-40 | Changes in levels of amyloid-beta-40 in blood from before to after acute intervention (stress/no-stress). | 9.5 hours | 
| Plasma amyloid-beta-42 | Changes in levels of amyloid-beta-42 in blood from before to after acute intervention (stress/no-stress). | 9.5 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Stress Reaction, Stress, Amyloid-Beta