PET Imaging of Brain mGluR1 Receptors Using [18F]FIMX

July 3, 2018 updated by: National Institute of Mental Health (NIMH)

Objective:

Metabotropic glutamate receptors (mGluRs) are G-protein coupled receptors that respond to glutamate by activating proteins inside nerve cells that affect cell metabolism, thereby fine-tuning the signals sent between cells to maintain balance in neuronal activity. mGluR subtype 1 (mGluR1s) are located in several brain regions, including the cerebellum, hippocampus, olfactory bulb, and basal ganglia. mGluR1 activation stimulates phospholipase C, resulting in phosphoinositide hydrolysis and increased intracellular calcium levels. Successful development of a positron emission tomography (PET) ligand to image mGlurR1 would impact clinical management of brain disorders characterized by disruptions in glutamatergic transmission, including anxiety and stress disorders, drug addiction, epilepsy, Huntington s disease, and Parkinson s disease. However, detailed study of mGluR1s has heretofore been hindered by the lack of high affinity and selective ligands for this receptor subtype.

The present protocol will evaluate the ability of a new PET ligand, [18F]FIMX, to image and quantify mGluR1 in the brain of healthy human volunteers. This protocol covers four phases:

  1. Phase 0: screening whole-body scan;
  2. Phase 1: kinetic brain imaging to quantify mGluR1 in brain relative to concurrent measurement of the parent radioligand in arterial plasma;
  3. Phase 2: if the tracer is successful in Phase 1, we will estimate radiation-absorbed doses of [18F]FIMX by performing whole body imaging;
  4. Phase 3: test-retest analysis of brain binding relative to concurrent measurement of the parent radioligand in arterial plasma.

Study Population:

Healthy adult female and male volunteers (n=22, ages 18 to 55) will undergo brain or whole-body imaging..

Design:

This study will begin with a screening whole-body scan to confirm that the radioactivity has fairly broad distribution in several organs. For absolute quantification of mGluR1, 22 healthy controls will have brain PET imaging using [18F]FIMX and an arterial line. Up to 12 of them will have a test-retest scan. Eight additional subjects will have a whole body PET scan for dosimetry, which does not require an arterial line.

<TAB>

Outcome Measures

To assess absolute quantitation of mGluR1 with [18F]FIMX, we will primarily use two outcome measures: the identifiability and time stability of distribution volume calculated with compartmental modeling. In test-retest study, we will calculate the retest variability. To assess whole-body biodistribution and dosimetry of [18F]FIMX we will use the organ time-activity curves....

Study Overview

Status

Completed

Conditions

Detailed Description

Objective:

Metabotropic glutamate receptors (mGluRs) are G-protein coupled receptors that respond to glutamate by activating proteins inside nerve cells that affect cell metabolism, thereby fine-tuning the signals sent between cells to maintain balance in neuronal activity. mGluR subtype 1 (mGluR1s) are located in several brain regions, including the cerebellum, hippocampus, olfactory bulb, and basal ganglia. mGluR1 activation stimulates phospholipase C, resulting in phosphoinositide hydrolysis and increased intracellular calcium levels. Successful development of a positron emission tomography (PET) ligand to image mGlurR1 would impact clinical management of brain disorders characterized by disruptions in glutamatergic transmission, including anxiety and stress disorders, drug addiction, epilepsy, Huntington s disease, and Parkinson s disease. However, detailed study of mGluR1s has heretofore been hindered by the lack of high affinity and selective ligands for this receptor subtype.

The present protocol will evaluate the ability of a new PET ligand, [18F]FIMX, to image and quantify mGluR1 in the brain of healthy human volunteers. This protocol covers four phases:

  1. Phase 0: screening whole-body scan;
  2. Phase 1: kinetic brain imaging to quantify mGluR1 in brain relative to concurrent measurement of the parent radioligand in arterial plasma;
  3. Phase 2: if the tracer is successful in Phase 1, we will estimate radiation-absorbed doses of [18F]FIMX by performing whole body imaging;
  4. Phase 3: test-retest analysis of brain binding relative to concurrent measurement of the parent radioligand in arterial plasma.

Study Population:

Healthy adult female and male volunteers (n=22, ages 18 to 55) will undergo brain or whole-body imaging.

Design:

This study will begin with a screening whole-body scan to confirm that the radioactivity has fairly broad distribution in several organs. For absolute quantification of mGluR1, 22 healthy controls will have brain PET imaging using [18F]FIMX and an arterial line. Up to 12 of them will have a test-retest scan. Eight additional subjects will have a whole body PET scan for dosimetry, which does not require an arterial line.

<TAB>

Outcome Measures

To assess absolute quantitation of mGluR1 with [18F]FIMX, we will primarily use two outcome measures: the identifiability and time stability of distribution volume calculated with compartmental modeling. In test-retest study, we will calculate the retest variability. To assess whole-body biodistribution and dosimetry of [18F]FIMX we will use the organ time-activity curves.

Study Type

Observational

Enrollment (Actual)

19

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
    • Maryland
      • Bethesda, Maryland, United States, 20892
        • National Institutes of Health Clinical Center, 9000 Rockville Pike

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

Ages Eligible for Study

18 years to 55 years (Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

  • INCLUSION CRITERIA:
  • Age 18 to 55.
  • Able to give written informed consent.

EXCLUSION CRITERIA:

  • Any current Axis I diagnosis.
  • Clinically significant laboratory abnormalities.
  • Positive HIV test.
  • Unable to have an MRI scan.
  • History of neurologic illness or injury with the potential to affect study data interpretation.
  • Recent exposure to radiation (i.e. PET from other research) that, when combined with this study, would be above the allowable limits.
  • Inability to lie flat on camera bed for at least two hours.
  • Pregnancy or breast feeding.
  • Able to get pregnant but does not use birth control.
  • History of drug or alcohol abuse within 6 months or a history of alcohol or drug dependence (excepting nicotine) within 3 years

Exclusion criteria for the dosimetry subjects are the same as reported above, with the exception of MRI contraindications, because an MRI will not be performed in these subjects.

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

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Ability to measure mGluR1 in brain
Time Frame: 3 years
3 years

Collaborators and Investigators

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

Sponsor

National Institute of Mental Health (NIMH)

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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

November 8, 2013

Primary Completion (Actual)

June 16, 2016

Study Completion (Actual)

June 16, 2016

Study Registration Dates

First Submitted

August 28, 2014

First Submitted That Met QC Criteria

August 29, 2014

First Posted (Estimate)

September 3, 2014

Study Record Updates

Last Update Posted (Actual)

July 5, 2018

Last Update Submitted That Met QC Criteria

July 3, 2018

Last Verified

July 18, 2016

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 140016
  • 14-M-0016

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.

Clinical Trials on Major Depressive Disorder

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in Lebanon

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

3
Subscribe