Examining the Effect of Acute Intermittent Hypoxia on Serum Blood Proteins and Lower Limb Function

April 1, 2025 updated by: Andrew Quesada Tan, University of Colorado, Boulder

Examining the Effect of Acute Intermittent Hypoxia on Serum Blood Proteins, Corticospinal Excitability, and Force Control in Persons With Incomplete Spinal Cord Injury

The goal of this study is to clarify mechanisms of acute intermittent hypoxia and to examine the effect on lower limb function in persons with chronic, incomplete spinal cord injury.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Enrolling by invitation

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The goal of this study is to clarify mechanisms of acute intermittent hypoxia by examining changes in blood biomarkers, neural excitability, and hemoglobin mass. We also aim to clarify how these changes relate to changes in lower limb function in persons with chronic, incomplete spinal cord injury by measuring force steadiness and voluntary muscle activation.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
100

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Colorado
      • Boulder, Colorado, United States, 80309
        • Andrew Tan

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • 18 to 75 years old (the latter to reduce likelihood of heart disease)
  • Medically stable with medical clearance from physician to participate
  • Motor-incomplete spinal cord injuries at or below C2 and at or above L5
  • AIS A-D at initial screen, or other non-traumatic spinal cord injury disorders (e.g. multiple sclerosis, ALS, tumors, acute transverse myelitis, etc.)
  • More than 1 year since iSCI to minimize confounds of spontaneous neurological recovery
  • Ability to advance one step overground with or without assistive devices;

Exclusion Criteria:

  • Severe concurrent illness or pain
  • Recurrent autonomic dysreflexia
  • History of cardiovascular/pulmonary complications
  • Concurrent physical therapy
  • Pregnant at time of enrollment or planning to become pregnant
  • Untreated painful musculoskeletal dysfunction, fracture or pressure sore
  • History of seizures or epilepsy
  • Recurring headaches
  • Concussion within the last six months
  • Depression or manic disorder
  • Metal implants in the head, or pacemaker
  • Aversion to needles

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: AIH Group
Participants will be exposed to 4 consecutive days of acute intermittent hypoxia (AIH): 15, 1.5 min episodes at 9% O2 alternating with 21% O2 at 1 min intervals.
Other: Acute Intermittent Hypoxia (AIH)
4 consecutive days of 15, 1.5 min episodes at 9% O2 (AIH) alternating with 21% O2 at 1 min intervals
No Intervention: SHAM Group
Participants will be exposed to 4 consecutive days of normoxia: 15, 1.5 min episodes at 21% O2 alternating with 21% O2 at 1 min intervals.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Change in the Transcranial Magnetic Stimulation Recruitment Curve Slope
Time Frame: Baseline and Day 4
The mean motor evoked potential response will be plotted against the corresponding stimulation intensity (% resting motor threshold) to produce a stimulus-response curve at 20% and 40% of maximum. We will measure TMS before the start of 4 consecutive days of AIH exposure. We will measure TMS within 24 hours of the final AIH exposure.
Baseline and Day 4
Change in Force Steadiness
Time Frame: Baseline and Day 4
The coefficient of variation of force will be calculated in both plantarflexion and dorsiflexion at 20% and 40% of maximum. We will measure coefficient of variation of force before the start of 4 consecutive days of AIH exposure. We will measure coefficient of variation of force within 24 hours of the final AIH exposure.
Baseline and Day 4
Change in Central Activation Ratio
Time Frame: Baseline and Day 4
We will measure the central activation ratio using supramaximal electrical stimulus over a peripheral nerve during maximum voluntary activation. We will measure the central activation ratio before the start of 4 consecutive days of AIH exposure. We will measure the central activation ratio within 24 hours of the final AIH exposure.
Baseline and Day 4
Change in hemoglobin mass
Time Frame: Baseline and Day 4
Using the optimized carbon monoxide rebreathing procedure we will evaluate hemoglobin concentration, carboxyhemoglobin, and hematocrit to calculate total hemoglobin mass, blood volume, and plasma volume. The optimized carbon monoxide rebreathing procedure will be done prior to the first hypoxia exposure and following the 4th hypoxia exposure.
Baseline and Day 4
Change in Serum Blood Brain Derived Neurotrophic Factor
Time Frame: Baseline, Day 1, Day 3, and Day 4
Serum blood brain derived neurotrophic factor (pg/mL) will be assessed using enzyme-linked immunosorbent assay. Blood will be sampled prior to AIH and within 1 hour following the 1st, 3rd, and 4th AIH exposure.
Baseline, Day 1, Day 3, and Day 4
Change in Serum Serotonin
Time Frame: Baseline, Day 1, Day 3, and Day 4
Serum serotonin (ng/mL) be assessed using enzyme-linked immunosorbent assay. Blood will be sampled prior to AIH and within 1 hour following the 1st, 3rd, and 4th AIH exposure.
Baseline, Day 1, Day 3, and Day 4
Change in Serum Erythropoetin
Time Frame: Baseline, Day 1, Day 3, and Day 4
Serum erythropoetin (mU/mL) will be assessed using enzyme-linked immunosorbent assay. Blood will be sampled prior to AIH and within 1 hour following the 1st, 3rd, and 4th AIH exposure.
Baseline, Day 1, Day 3, and Day 4

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Axial damage ratio
Time Frame: Baseline
Using MRI, we will quantify the axial damage ratio. Prior to participation in the study we will obtain an MRI for quantification of axial damage ratio
Baseline
6-Minute Walk Test
Time Frame: Baseline and Day 4
We will assess the distance walked in 6-minutes. The 6-minute walk test will be completed prior to the first exposure to hypoxia and following the 4th exposure of hypoxia.
Baseline and Day 4
10-Meter Walk Test
Time Frame: Baseline and Day 4
We will assess how long it takes subjects to walk 10 meters. The 10-Meter walk test will be done prior to the first hypoxia exposure, and following the 4th hypoxia exposure.
Baseline and Day 4

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of Colorado, Boulder

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
University of Colorado, Denver
Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
March 1, 2024

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
March 1, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
August 1, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
March 11, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 25, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
April 2, 2025

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 4, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 1, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
March 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 23-1275
  • 1R03HD115657-01 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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