Traumatic Brain InjuryCOPETBINCT07357090
Carbon Dioxide Administration and Brain Waste Clearance
A study testing Hypercapnia task performed during fMRI in people with Traumatic Brain Injury and Aging Disorder, run by Andrew Mayer at 1 site in United States.
Trial summary
The current study tests whether different exposures to carbon dioxide (CO2) can safely result in the increased movement of proteins from the brain into the blood. The investigators believe that this would be a proxy for the brain clearing waste products more effectively. Read more about this study
- Who is it for?
- Ages 18 to 82 yearsHealthy volunteers can take part
- Conditions the study is for
- Traumatic Brain Injury, Aging Disorder, Magnetic Resonance Imaging (MRI)
- What is being tested?
- Hypercapnia task performed during fMRI
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 200 participants
- Where
- 1 siteUnited States
- Study dates
- Dec 2026to Feb 2032
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 82 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Inclusion criteria for TBI cohort: 1) Able to give valid informed consent, 2) 18-82 years old, 3) history of TBI of any severity level (mild, moderate or severe) that was sustained in adulthood (age 18 and older), which will be confirmed using a semi-structured identification method (includes asking about loss of consciousness, posttraumatic amnesia, and feeling dazed/confused).
Inclusion criteria for Healthy Subjects cohort: 1) Able to give valid informed consent and 2) 18-82 years old years old.
Exclusion criteria for TBI cohort: 1) contraindications to MRI scanning including pregnancy or claustrophobia, 2) unable to give valid informed consent, incarcerated, 3) diagnosed with Alzheimer's, ADRD or mild cognitive impairment, 4) pre-existing history of autism spectrum disorders, intellectual disability, serious neurological (e.g., epilepsy, tumors, other conditions requiring neurosurgery) or psychiatric disorders (requiring hospitalization) prior to TBI onset, 5) current or previous diagnosis of a psychosis spectrum disorder or bipolar disorder, 6) respiratory diseases or pulmonary conditions that may increase the risk of study procedures (e.g., severe asthma, chronic obstructive pulmonary disease or other significant respiratory disorders), 7) a history of cardiac arrythmias 8) history of a current substance use disorder, 9) non-English fluency (based on screener), 10) Weigh under 110 pounds for blood draw.
Exclusion criteria for Healthy Subjects cohort: 1) contraindications to MRI scanning including pregnancy or claustrophobia, 2) unable to give valid informed consent, incarcerated, 3) diagnosed with Alzheimer's, ADRD or mild cognitive impairment, 4) history of developmental, neurological, or psychiatric disorders requiring hospitalization, 5) regular use of any substance in the past six months (i.e., no current use confirmed with urine screening), 6) previous head injury with greater than 30 minutes loss of consciousness, 7) respiratory diseases or pulmonary conditions that may increase the risk of study procedures (e.g., severe asthma, chronic obstructive pulmonary disease or other significant respiratory disorders), 8) a history of cardiac arrythmias, 9) non-English fluency (based on screener), 10) Weigh under 110 pounds for blood draw.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
The Mind Research Network
Albuquerque, New Mexico, 87106
Sadie LaBauve, PhD, 505-272-8739, slabauve@mrn.org
Andrew Mayer, Phd
About this study
Official title: Mechanisms Underlying Carbon Dioxide Induced Protein Efflux in Health and Traumatic Brain Injury
The current study tests whether different exposures to carbon dioxide (CO2) can safely result in the increased movement of proteins from the brain into the blood. The investigators believe that this would be a proxy for the brain clearing waste products more effectively. The current study will use a counter-balanced design, in which individuals with and without a history of traumatic brain injury (TBI) will receive different levels of CO2 (targeted changes of approximately 5 or 10 mmHG in end-tidal CO2) approximately one week apart. The counter-balanced design means that each participant receives a single dose of CO2 at each visit, and different doses of CO2 at each visit. The order in which participants receive the dose is randomized, and the participant will not be informed of the dose.
Read the detailed description
Impaired clearance of metabolic waste and cellular debris is a hallmark of TBI and other neurodegenerative conditions. Clearance primarily occurs through glymphatic/lymphatic pathways, which is partially dependent on the influx of cerebrospinal fluid (CSF). CSF flow is greatest during sleep, when low-frequency oscillations in cerebral blood volume are most prominent. The investigators propose that changing levels of cerebral blood volume via the administration of CO2 will drive CSF flow and ultimately promote brain waste clearance. The proposed study is significant because it examines whether prescribed CO2 can enhance protein efflux (i.e., a surrogate for waste clearance), and the biological mechanisms that may mediate this mechanism in both health and disease. The first study aim is therefore to determine whether the administration of CO2, a potent vasodilator, can be prescribed to mimic global changes in cerebral blood volume in a dose-dependent fashion. Basal protein levels and efflux (i.e., change from baseline) are quantified using high-sensitivity proteomic platforms. The second aim is to examine how individual differences in cerebrovascular function and other disease factors such as atrophy affect CO2-induced protein efflux.
Using a counter-balanced (AB/BA) design, individuals (aged 18-82 years) with chronic TBI and individuals without a history of TBI (healthy subjects) will be dosed to achieve either 5 or 10 mmHG changes in end-tidal CO2. Importantly, the proposed cerebrovascular mechanisms and surrogate markers of waste clearance are readily quantified in humans using advanced MR-imaging and commercially available proteomic platforms, exponentially increasing their clinical translation.
- Being tested
- Hypercapnia task performed during fMRI
- Keywords
- Traumatic Brain Injury, Magnetic Resonance Imaging
- Medical subject headings
- Brain Injuries, Traumatic
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Hypercapnia task performed during fMRIOther
This study looks at different levels of carbon dioxide (CO2) exposure (changes of approximately 5 or 10 mmHg) on the brain and proteins in blood, in response to a hypercapnia task while participants undergo MRI. This sequence will dynamically mix gases to target an increase of 5 or 10 mmHg in ETCO2 (increase of ~5-7% CO2 and equal decrease in nitrogen) while keeping O2 constant.
| Study group | Role | What they receive |
|---|---|---|
| Individuals with TBI | Experimental | A counter-balanced, cross-over design (AB/BA), in which individuals with TBI (aged 18-82 years) may be dosed to achieve 5 or 10 mmHG changes in ETCO2 across multiple visits. Receives: Other: Hypercapnia task performed during fMRI |
| Healthy Subjects | Experimental | A counter-balanced, cross-over design (AB/BA), in which individuals without a history of TBI (healthy subjects, aged 18-82 years) may be dosed to achieve 5 or 10 mmHG changes in ETCO2 across multiple visits. Receives: Other: Hypercapnia task performed during fMRI |
What is being measured
The primary outcome is the main question the study is designed to answer.
Cerebrovascular Reactivity (CVR), vascular-elicited bulk cerebral spinal fluid (VE-bCSF)
Cerebrovascular reactivity (CVR) will be quantified using time-shifted end-tidal carbon dioxide (ETCO₂) regressors to model blood oxygen level-dependent (BOLD) changes using functional magnetic resonance imaging, capturing the temporally lagged positive relationship between ETCO₂ and the BOLD signal. Vascular enhanced changes in bulk CSF flow will be assessed by regressing band-pass filtered global grey matter signals and their derivatives on CSF bulk flow to capture the temporally lagged, negative relationship. Both of these measurements are in arbitrary units, and will be quantified by calculating percent signal change and statistical fit between regressors.
Measured: 2.5 hours post-intervention. Data will be reported at the conclusion of the study for all participants.
Protein Efflux (Surrogate Measure of Brain Waste Clearance)
Protein efflux from the brain to the blood will be measured using Quanterix platform, with primary proteins including neurofilament light chain, brain-derived tau and glial fibrillary acidic protein (units=picogram/milligram).
For neurofilament light chain (NfL), the limit of detection (LOD) is 0.104 pg/mL, the range is 0.025-0.276 pg/mL, and the lower limit of quantification (LLOQ) is 0.241 pg/mL. For glial fibrillary acidic protein (GFAP), the LOD is 0.221 pg/mL, the range is 0.042-0.481 pg/mL, and the LLOQ is 0.467 pg/mL. For brain-derived tau (BD Tau), the LOD is 0.024 pg/mL, the range is 0.007-0.059 pg/mL, and the LLOQ is 0.053 pg/mL. All values are obtained from the Quanterix website datasheets.
Measured: Blood will be drawn at baseline, immediately prior to hypercapnia, 45 minutes post-hypercapnia, 90 minutes post-hypercapnia and 150 minutes post-hypercapnia. Data will be reported at the conclusion of the study for all participants.
Secondary outcomes (1)
Symptoms
Participants will be asked to rate 4 different symptoms (current headache, current dizziness, current nausea, and current fogginess) on a Likert scale (range 0-10 for each symptom) at multiple times during the study. Symptom ratings will be summed to create a single summary score that can range between 0 and 40.
Measured: After the first blood draw (i.e., blood collected at baseline), 10 and 20 minutes post-hypercapnia, as well as after blood collected 90-minutes post-hypercapnia. Data will be reported at the conclusion of the study for all participants.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Jan 2026
- Study startDec 2026 (estimated)
- Primary completionJan 2031 (estimated)
- Study completionFeb 2032 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Traumatic Brain InjuryStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 200 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Andrew Mayer
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, Andrew Mayer, The Mind Research Network
- Investigators
- Andrew R Mayer, Phd, Principal investigator, Mind Research Network
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07357090
- Sponsor's protocol ID
- 25-415
- Acronym
- COPETBI
- Status last verified
- Dec 2025
- First submitted
- 9 Jan 2026
- Last updated
- 6 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 6 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Mechanisms Underlying Carbon Dioxide Induced Protein Efflux in Health and Traumatic Brain Injury
- ClinicalTrials.gov ID
- NCT07357090
- Acronym / sponsor ID
- COPETBI / 25-415
- Keywords
- Traumatic Brain Injury, Magnetic Resonance Imaging
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 200 participants (estimated)
- Lead sponsor
- Andrew MayerUniversity, hospital or other
- Study start
- Dec 2026 (estimated)
- Primary completion
- Jan 2031 (estimated)
- Study completion
- Feb 2032 (estimated)
- First posted
- 21 Jan 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The current study tests whether different exposures to carbon dioxide (CO2) can safely result in the increased movement of proteins from the brain into the blood. The investigators believe that this would be a proxy for the brain clearing waste products more effectively. The current study will use a counter-balanced design, in which individuals with and without a history of traumatic brain injury (TBI) will receive different levels of CO2 (targeted changes of approximately 5 or 10 mmHG in end-tidal CO2) approximately one week apart. The counter-balanced design means that each participant receives a single dose of CO2 at each visit, and different doses of CO2 at each visit. The order in which participants receive the dose is randomized, and the participant will not be informed of the dose.
Detailed description
Impaired clearance of metabolic waste and cellular debris is a hallmark of TBI and other neurodegenerative conditions. Clearance primarily occurs through glymphatic/lymphatic pathways, which is partially dependent on the influx of cerebrospinal fluid (CSF). CSF flow is greatest during sleep, when low-frequency oscillations in cerebral blood volume are most prominent. The investigators propose that changing levels of cerebral blood volume via the administration of CO2 will drive CSF flow and ultimately promote brain waste clearance. The proposed study is significant because it examines whether prescribed CO2 can enhance protein efflux (i.e., a surrogate for waste clearance), and the biological mechanisms that may mediate this mechanism in both health and disease. The first study aim is therefore to determine whether the administration of CO2, a potent vasodilator, can be prescribed to mimic global changes in cerebral blood volume in a dose-dependent fashion. Basal protein levels and efflux (i.e., change from baseline) are quantified using high-sensitivity proteomic platforms. The second aim is to examine how individual differences in cerebrovascular function and other disease factors such as atrophy affect CO2-induced protein efflux.
Using a counter-balanced (AB/BA) design, individuals (aged 18-82 years) with chronic TBI and individuals without a history of TBI (healthy subjects) will be dosed to achieve either 5 or 10 mmHG changes in end-tidal CO2. Importantly, the proposed cerebrovascular mechanisms and surrogate markers of waste clearance are readily quantified in humans using advanced MR-imaging and commercially available proteomic platforms, exponentially increasing their clinical translation.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind (participant)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Individuals with TBI | Experimental | Other: Hypercapnia task performed during fMRIA counter-balanced, cross-over design (AB/BA), in which individuals with TBI (aged 18-82 years) may be dosed to achieve 5 or 10 mmHG changes in ETCO2 across multiple visits. |
| Healthy Subjects | Experimental | Other: Hypercapnia task performed during fMRIA counter-balanced, cross-over design (AB/BA), in which individuals without a history of TBI (healthy subjects, aged 18-82 years) may be dosed to achieve 5 or 10 mmHG changes in ETCO2 across multiple visits. |
Who may qualify
- Ages
- 18 to 82 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Hypercapnia task performed during fMRIThis study looks at different levels of carbon dioxide (CO2) exposure (changes of approximately 5 or 10 mmHg) on the brain and proteins in blood, in response to a hypercapnia task while participants undergo MRI. This sequence will dynamically mix gases to target an increase of 5 or 10 mmHg in ETCO2 (increase of ~5-7% CO2 and equal decrease in nitrogen) while keeping O2 constant. | Other | Healthy Subjects, Individuals with TBI |
Primary outcome
Cerebrovascular Reactivity (CVR), vascular-elicited bulk cerebral spinal fluid (VE-bCSF)
Time frame: 2.5 hours post-intervention. Data will be reported at the conclusion of the study for all participants.
Cerebrovascular reactivity (CVR) will be quantified using time-shifted end-tidal carbon dioxide (ETCO₂) regressors to model blood oxygen level-dependent (BOLD) changes using functional magnetic resonance imaging, capturing the temporally lagged positive relationship between ETCO₂ and the BOLD signal. Vascular enhanced changes in bulk CSF flow will be assessed by regressing band-pass filtered global grey matter signals and their derivatives on CSF bulk flow to capture the temporally lagged, negative relationship. Both of these measurements are in arbitrary units, and will be quantified by calculating percent signal change and statistical fit between regressors.
Protein Efflux (Surrogate Measure of Brain Waste Clearance)
Time frame: Blood will be drawn at baseline, immediately prior to hypercapnia, 45 minutes post-hypercapnia, 90 minutes post-hypercapnia and 150 minutes post-hypercapnia. Data will be reported at the conclusion of the study for all participants.
Protein efflux from the brain to the blood will be measured using Quanterix platform, with primary proteins including neurofilament light chain, brain-derived tau and glial fibrillary acidic protein (units=picogram/milligram). For neurofilament light chain (NfL), the limit of detection (LOD) is 0.104 pg/mL, the range is 0.025-0.276 pg/mL, and the lower limit of quantification (LLOQ) is 0.241 pg/mL. For glial fibrillary acidic protein (GFAP), the LOD is 0.221 pg/mL, the range is 0.042-0.481 pg/mL, and the LLOQ is 0.467 pg/mL. For brain-derived tau (BD Tau), the LOD is 0.024 pg/mL, the range is 0.007-0.059 pg/mL, and the LLOQ is 0.053 pg/mL. All values are obtained from the Quanterix website datasheets.
1 secondary outcome
Symptoms
Time frame: After the first blood draw (i.e., blood collected at baseline), 10 and 20 minutes post-hypercapnia, as well as after blood collected 90-minutes post-hypercapnia. Data will be reported at the conclusion of the study for all participants.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 Oct 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Andrew R Mayer, Phd principal investigator
Mind Research Network
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Hypercapnia task performed during fMRI in people with Traumatic Brain Injury and Aging Disorder, run by Andrew Mayer at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 6 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Sadie LaBauve, PhD (505-272-8739, slabauve@mrn.org), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Cerebrovascular Reactivity (CVR), vascular-elicited bulk cerebral spinal fluid (VE-bCSF) (time frame: 2.5 hours post-intervention. Data will be reported at the conclusion of the study for all participants.). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 6 Oct 2026; AzTrials last refreshed its copy on 26 Oct 2026.