Improving Human Cerebrovascular Function Using Acute Intermittent Hypoxia

NCT ID: NCT05164705

Last Updated: 2024-07-09

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

NA

Total Enrollment

33 participants

Study Classification

INTERVENTIONAL

Study Start Date

2022-05-03

Study Completion Date

2024-04-05

Brief Summary

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This study uses magnetic resonance imaging to determine whether 3 weeks of repeated exposure to Acute Intermittent Hypoxia can improve brain blood flow or blood flow regulation in healthy adults.

Detailed Description

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This study aims to identify an intervention to improve the function of blood vessels in the human brain, in order to mitigate damage to overall brain function and improve health outcomes across the lifespan. Hypoxia is a potent driver of angiogenesis and vascular plasticity, and acute intermittent hypoxia (AIH) protocols, in which an individual alternates between breathing mildly hypoxic air and normal air, are being rigorously examined for their potential in improving human physiology. This study tests whether AIH evokes beneficial vascular plasticity in the human brain, using a randomized crossover design to determine the impact of different daily AIH or sham interventions on MRI measures of cerebrovascular physiology.

Healthy, able-bodied participants between 21 and 50 years old will be invited to participate in this study. The daily AIH intervention consists of repeated visits to the PI laboratory over a three-week period to have an AIH or sham protocol administered via a hypoxia generator and face mask (Hyp-123, Hypoxico). Blood pressure readings will be taken before and after all intervention visits, and SpO2 levels continuously recorded for safety monitoring.

The effectiveness of the different interventions at improving cerebrovascular function will be assessed using MRI. In the week prior to each intervention period the participant will undergo MRI scanning. In addition to structural and diffusion weighted scans, multiple perfusion metrics will be extracted. Whole-brain cerebral blood flow will be measured using phase-contrast MRI, and quantitative CBF maps of regional perfusion will be measured using arterial spin labeling MRI. These perfusion metrics will be acquired three times: during normoxic (baseline), hypoxic, and hypercapnic conditions. Changes in perfusion values during gas challenges will measure whole-brain and regional cerebrovascular reactivity. The MRI protocol will be repeated one day after the last intervention visit.

Conditions

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Healthy Brain Perfusion

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

CROSSOVER

Randomized sham-controlled crossover trial
Primary Study Purpose

BASIC_SCIENCE

Blinding Strategy

SINGLE

Participants
Participants will not know whether they are receiving active or sham hypoxia during individual AIH sessions.

Study Groups

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Intermittent Hypoxia

Participant will visit our center 2-4 times per week for three weeks to receive Acute Intermittent Hypoxia.

Group Type ACTIVE_COMPARATOR

Acute Intermittent Hypoxia

Intervention Type OTHER

Participants will wear a non-rebreathing face mask and alternate between breathing 9% O2 gas mixture for up to 1 minute, or until the target SpO2 of 85 percent is reached, and normal room air (21 percent O2) until 2 minutes are complete. This cycle will be repeated 15 times, resulting in a 30-minute protocol.

Sham Intermittent Hypoxia

Participants will visit our center 2-4 times per week for three weeks to receive Sham Intermittent Hypoxia.

Group Type SHAM_COMPARATOR

Sham Acute Intermittent Hypoxia

Intervention Type OTHER

Participants will wear a non-rebreathing face mask and breathe normal air (21 percent O2) for 30-minutes.

Interventions

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Acute Intermittent Hypoxia

Participants will wear a non-rebreathing face mask and alternate between breathing 9% O2 gas mixture for up to 1 minute, or until the target SpO2 of 85 percent is reached, and normal room air (21 percent O2) until 2 minutes are complete. This cycle will be repeated 15 times, resulting in a 30-minute protocol.

Intervention Type OTHER

Sham Acute Intermittent Hypoxia

Participants will wear a non-rebreathing face mask and breathe normal air (21 percent O2) for 30-minutes.

Intervention Type OTHER

Eligibility Criteria

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Inclusion Criteria

* Healthy volunteers between ages of 21 and 50 years
* No known neurological, respiratory or vascular conditions
* Safe to be scanned using MRI
* Able to communicate in English

Exclusion Criteria

* MRI contraindications as indicated on MRI safety screening form
* Subjects with pacemakers, cochlear (in the ear) implants, or aneurysm clips or subjects who have worked with metal
* Pregnant women
* Individuals with known neurological or vascular conditions
* Individuals with sleep apnea, emphysema, or other respiratory conditions
* Individuals with severe claustrophobia
* Subjects unwilling or unable to give written informed consent in English
* Prisoners
* Frequent smoker
* Allergy to Tegaderm
* Blood pressure greater than 140/90 or less than 90/55.
* Individuals who report headaches, feeling dizzy or light-headed, or have heart palpitations on the day of the study.
* Individuals prescribed Aripiprazole and/or Lamotrigine\*

Note, mild (well-controlled) asthma is not immediate grounds for exclusion.

\*Other prescription medications may be grounds for exclusion; prescription medication information will be acquired during initial screening and at subsequent follow-up visits
Minimum Eligible Age

21 Years

Maximum Eligible Age

50 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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Northwestern University

OTHER

Sponsor Role lead

Responsible Party

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Molly Bright

Assistant Professor

Responsibility Role PRINCIPAL_INVESTIGATOR

Principal Investigators

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Molly G Bright, DPhil

Role: PRINCIPAL_INVESTIGATOR

Northwestern University

Locations

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Northwestern University

Chicago, Illinois, United States

Site Status

Countries

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United States

References

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Johnson HR, Wang MC, Stickland RC, Chen Y, Parrish TB, Sorond FA, Bright MG. Variable cerebral blood flow responsiveness to acute hypoxic hypoxia. Front Physiol. 2025 Mar 12;16:1562582. doi: 10.3389/fphys.2025.1562582. eCollection 2025.

Reference Type DERIVED
PMID: 40144550 (View on PubMed)

Provided Documents

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Document Type: Informed Consent Form

View Document

Other Identifiers

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STU00215559

Identifier Type: -

Identifier Source: org_study_id

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