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Metabolic Changes in the Activated Human Visual Cortex During Mild Hypoxia

Primary Purpose

Brain Hypoxia

Status

Completed

Phase

Not Applicable

Locations

United States

Study Type

Interventional

Intervention

Mild Hypoxia

About this trial

This is an interventional basic science trial for Brain Hypoxia focused on measuring Functional MRS, Glutamate

Eligibility Criteria

18 Years - 40 Years (Adult)MaleAccepts Healthy Volunteers

Inclusion Criteria:

Those volunteers who are evaluated as normal and not met exclusion criteria will be potential candidates for this study.

Exclusion Criteria:

Subjects with any type of bio-implant activated by mechanical, electronic, or magnetic means (e.g. cochlear implants, pacemakers, neurostimulators, biostimulators, electronic infusion pumps, etc.).
Subjects with any type of ferromagnetic bio-implant that could potentially be displaced or damaged, such as aneurysm clips, metallic skull plates, etc.
Females.
Subjects that exhibit noticeable anxiety and/or claustrophobia.
Subjects who cannot adhere to the experimental protocol for any reason.
Subjects who have cardiac or known circulatory impairment, and/or the inability to perspire (poor thermoregulatory function).
Subjects who have known conditions which can lead to emergency medical care.
Been diagnosed by a physician as having a psychiatric disorder, substance abuse, neurological, cardiovascular.
Been diagnosed by a physician as having respiratory diseases.
Had a brain tumor or stroke.
Started taking chemotherapy or immunomodulatory agents, or had any radiation treatment that could affect the brain.
Had two or more seizures, or been given a diagnosis of epilepsy.
Gotten a non-removable piercing or permanent eyeliner.
Had a head injury that caused you to lose consciousness for more than 30 minutes or have amnesia for more than 24 hours.
Anyone with a history of sleep apnea or head trauma that may have caused Traumatic Brain Injury (TBI).
Gotten some type of metal in your body, either from a medical procedure or an injury.
Male subjects with long beard which wouldn't allow a complete seal between the mask and the face.
Anyone who is not able to see long distance without glasses or contacts.

Sites / Locations

Center for Magnetic Resoance Research, University of Minnesota

Arms of the Study

Arm 1

Arm Type

Experimental

Arm Label

Mild Hypoxia

Arm Description

Subjects are exposed to an intervention that controls the composition of breathed air by using a gas blender (RespirAct). Subjects undergo MRI and MRS while breathing air with both normal oxygen concentration (normoxia) and reduced oxygen concentration (mild hypoxia).

Outcomes

Primary Outcome Measures

Change in Glutamate Concentration During a Visual Stimulus Measured by fMRS at Normoxia

Relative change in glutamate concentration from rest to visual stimulation as measured by fMRS (with water suppression) in the primary visual cortex during conditions of normoxia.

Change in Glutamate Concentration During a Visual Stimulus Measured by Functional MRS at Hypoxia

Relative change in glutamate concentration from rest to visual stimulation as measured by fMRS (with water suppression) in the primary visual cortex during conditions of hypoxia.

Secondary Outcome Measures

Brain Activity Measured by Blood Oxygenation Level Dependent (BOLD) Signal at Normoxia

Relative change in water signal intensity from rest to visual stimulation as measured by fMRS (without water suppression) in the primary visual cortex during conditions of normoxia.

Brain Activity Measured by Blood Oxygenation Level Dependent (BOLD) Signal at Hypoxia

Relative change in water signal intensity from rest to visual stimulation as measured by fMRS (without water suppression) in the primary visual cortex during conditions of hypoxia.

Full Information

NCT ID

NCT02482571

First Posted

June 23, 2015

Last Updated

March 11, 2019

Sponsor

University of Minnesota

1. Study Identification

Unique Protocol Identification Number

NCT02482571

Brief Title

Metabolic Changes in the Activated Human Visual Cortex During Mild Hypoxia

Official Title

Metabolic Changes in the Activated Human Visual Cortex During Mild Hypoxia

Study Type

Interventional

2. Study Status

Record Verification Date

March 2019

Overall Recruitment Status

Completed

Study Start Date

August 13, 2015 (Actual)

Primary Completion Date

September 26, 2016 (Actual)

Study Completion Date

September 26, 2016 (Actual)

3. Sponsor/Collaborators

Responsible Party, by Official Title

Sponsor

Name of the Sponsor

University of Minnesota

4. Oversight

Data Monitoring Committee

Yes

5. Study Description

Brief Summary

The primary objective of this research is to measure changes in neurochemical concentrations during stimulation of the primary visual cortex, in both conditions of normoxia (normal oxygen availability) and induced mild hypoxia (reduced oxygen availability).

Detailed Description

The goal is to determine the effect of mild hypoxia on human brain energy metabolism of healthy young adult subjects. For this purpose, the Investigator will utilize non-invasive imaging modalities based on functional magnetic resonance spectroscopy (fMRS) to estimate metabolic changes during a visual stimulus, while subjects are exposed to well-controlled gas mixtures that resembles conditions of either normoxia or mild hypoxia. Identifying the impact of mild hypoxia on functional brain energy metabolism in the healthy human brain is a crucial step for generating hypotheses in multiple patient populations that experience mild hypoxia as consequence of their pathological condition, such as in sleep apnea and traumatic brain injury. The Investigator hypothesize that the energetic demands of neuronal activation as revealed by fMRS will not be affected by mild hypoxia.

6. Conditions and Keywords

Primary Disease or Condition Being Studied in the Trial, or the Focus of the Study

Brain Hypoxia

Keywords

Functional MRS, Glutamate

7. Study Design

Primary Purpose

Basic Science

Study Phase

Not Applicable

Interventional Study Model

Single Group Assignment

Masking

None (Open Label)

Allocation

N/A

Enrollment

25 (Actual)

8. Arms, Groups, and Interventions

Arm Title

Mild Hypoxia

Arm Type

Experimental

Arm Description

Intervention Type

Device

Intervention Name(s)

Mild Hypoxia

Intervention Description

During normoxia, the computer-controlled gas blender provides a gas mixture that generates pressures of expired O2 and CO2 similar to the resting values measured for each subject (32-35mmHg and 100-110 mmHg, respectively). During mild hypoxia, we will target the same expired CO2 of normoxia and a 60 mmHg reduction of expired O2 from the resting value (to a minimum limit of 50 mmHg), which is expected to reduce arterial oxygen saturation to 82-85%. In mild hypoxia, the fraction of inspired oxygen is reduced from ~21% (room air) to ~12% (equivalent to an altitude of 4000 meters). During both conditions of normoxia and mild hypoxia, the brain activity of subjects is monitored with functional magnetic resonance spectroscopy (fMRS) while they are presented with visual stimuli.

Primary Outcome Measure Information:

Title

Change in Glutamate Concentration During a Visual Stimulus Measured by fMRS at Normoxia

Description

Relative change in glutamate concentration from rest to visual stimulation as measured by fMRS (with water suppression) in the primary visual cortex during conditions of normoxia.

Time Frame

Baseline and Visual Stimulation at 4 minutes

Title

Change in Glutamate Concentration During a Visual Stimulus Measured by Functional MRS at Hypoxia

Description

Relative change in glutamate concentration from rest to visual stimulation as measured by fMRS (with water suppression) in the primary visual cortex during conditions of hypoxia.

Time Frame

Baseline and Visual Stimulation at 4 minutes

Secondary Outcome Measure Information:

Title

Brain Activity Measured by Blood Oxygenation Level Dependent (BOLD) Signal at Normoxia

Description

Relative change in water signal intensity from rest to visual stimulation as measured by fMRS (without water suppression) in the primary visual cortex during conditions of normoxia.

Time Frame

Baseline and Visual Stimulation at 30 seconds

Title

Brain Activity Measured by Blood Oxygenation Level Dependent (BOLD) Signal at Hypoxia

Description

Relative change in water signal intensity from rest to visual stimulation as measured by fMRS (without water suppression) in the primary visual cortex during conditions of hypoxia.

Time Frame

Baseline and Visual Stimulation at 30 seconds

10. Eligibility

Sex

Male

Gender Based

Yes

Minimum Age & Unit of Time

18 Years

Maximum Age & Unit of Time

40 Years

Accepts Healthy Volunteers

Eligibility Criteria

Inclusion Criteria: Those volunteers who are evaluated as normal and not met exclusion criteria will be potential candidates for this study. Exclusion Criteria: Subjects with any type of bio-implant activated by mechanical, electronic, or magnetic means (e.g. cochlear implants, pacemakers, neurostimulators, biostimulators, electronic infusion pumps, etc.). Subjects with any type of ferromagnetic bio-implant that could potentially be displaced or damaged, such as aneurysm clips, metallic skull plates, etc. Females. Subjects that exhibit noticeable anxiety and/or claustrophobia. Subjects who cannot adhere to the experimental protocol for any reason. Subjects who have cardiac or known circulatory impairment, and/or the inability to perspire (poor thermoregulatory function). Subjects who have known conditions which can lead to emergency medical care. Been diagnosed by a physician as having a psychiatric disorder, substance abuse, neurological, cardiovascular. Been diagnosed by a physician as having respiratory diseases. Had a brain tumor or stroke. Started taking chemotherapy or immunomodulatory agents, or had any radiation treatment that could affect the brain. Had two or more seizures, or been given a diagnosis of epilepsy. Gotten a non-removable piercing or permanent eyeliner. Had a head injury that caused you to lose consciousness for more than 30 minutes or have amnesia for more than 24 hours. Anyone with a history of sleep apnea or head trauma that may have caused Traumatic Brain Injury (TBI). Gotten some type of metal in your body, either from a medical procedure or an injury. Male subjects with long beard which wouldn't allow a complete seal between the mask and the face. Anyone who is not able to see long distance without glasses or contacts.

Overall Study Officials:

First Name & Middle Initial & Last Name & Degree

Silvia Mangia, PhD

Organizational Affiliation

University of Minnesota

Official's Role

Principal Investigator

Facility Information:

Facility Name

Center for Magnetic Resoance Research, University of Minnesota

City

Minneapolis

State/Province

Minnesota

ZIP/Postal Code

55455

Country

United States

12. IPD Sharing Statement

Plan to Share IPD

Citations:

PubMed Identifier

18396415

Citation

Ho YC, Vidyasagar R, Shen Y, Balanos GM, Golay X, Kauppinen RA. The BOLD response and vascular reactivity during visual stimulation in the presence of hypoxic hypoxia. Neuroimage. 2008 Jun;41(2):179-88. doi: 10.1016/j.neuroimage.2008.02.048. Epub 2008 Mar 6.

Results Reference

background

PubMed Identifier

16079793

Citation

Tuunanen PI, Murray IJ, Parry NR, Kauppinen RA. Heterogeneous oxygen extraction in the visual cortex during activation in mild hypoxic hypoxia revealed by quantitative functional magnetic resonance imaging. J Cereb Blood Flow Metab. 2006 Feb;26(2):263-73. doi: 10.1038/sj.jcbfm.9600186.

Results Reference

background

Links:

URL

http://www.cmrr.umn.edu/facultystaff/mangia.shtml

Description

Profile of Principle Investigator

Learn more about this trial

Metabolic Changes in the Activated Human Visual Cortex During Mild Hypoxia

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