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Completed

NCT Number: NCT02213575

Study 3: Minocycline Decreases Microglia Activation

This study is a mechanistic study that will enroll 9 subjects who are participating in NCT02133872 (which is designed to evaluate minocycline to test the hypothesis that minocycline treatment would produce antihypertensive effects in drug-resistant neurogenic hypertensive individuals) to test whether the antihypertensive effect of minocycline is associated with a decrease in activated microglia in central nervous system autonomic regions as evidenced by changes in PET and MRI imaging.

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Key information

Conditions

Hypertension Cardiovascular Diseases Vascular Diseases

Age range

18 year–85 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2

Primary location

UF Health Cardiovascular Clinic

Gainesville, Florida, 32610, United States

About this study

This study (Study 3) will recruit 9 subjects from NCT02133872 (Study1) who will agree to undergo additional autonomic testing and imaging studies at baseline and after 6 months of study treatment. Specialized imaging of the brain using magnetic resonance imaging (MRI) and positron emission tomography (PET) scanning will be conducted at the Montreal Neurological Institute, in Montreal Canada.

For this study (Study 3) we include participants being enrolled Study 1 and/or participants who have completed participation in Study 1 and have not taken minocycline for 2 months will be approached to enroll in Study 3.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

for Minocycline Subjects:

  • Subjects participating in Study 1 will be eligible to participate.
  • (For Study 3 Participants only) Willing to travel to Montreal, Canada for specialized imaging of the participant's brain using magnetic resonance imaging (MRI), positron emission tomography (PET) scanning, Autonomic Nervous System Testing and blood drawing- if participant qualifies

Exclusion criteria

for Minocycline Subjects:

-Female participants with positive pregnancy test.

Inclusion criteria

for Controls:

  • No diagnosis of neurogenic (treatment-resistant) hypertension.
  • Not treated with minocycline.
  • Willing to travel to Montreal, Canada for brain imaging and testing.
  • Able to provide informed consent.

Exclusion criteria

for Controls:

-Female participants with positive pregnancy test.

Treatment and study plan

Minocycline

Drug

Subjects will receive the dose of Minocycline determined to best lower BP and will undergo baseline and 26 week follow-up MRI and PET scans for changes in the paraventricular nucleus.

Primary outcomes

  1. PET Changes in the Paraventricular Nucleus From Baseline to 26 Weeks.

    Time frame: Change in Baseline to 26 weeks

    This outcome represents the change in PET signal intensity in the bilateral paraventricular nucleus before and after minocycline treatment. PET imaging was performed using the radiotracer [¹¹C]PBR28, which binds to the Translocator Protein (TSPO), a marker of activated microglia and neuroinflammation. To ensure accurate anatomical localization, each participant's PET scan was co-registered with a high-resolution T1-weighted MRI. Regions of interest (ROIs) were manually drawn on the MRI and applied to the PET images to extract PET signal from the same brain structures. The signal was quantified as non-displaceable binding potential (BP_ND). The change in signal is calculated as the average change in BP_ND at baseline minus the average change in BP_ND after treatment. A positive value indicates that the PET signal decreased following treatment, reflecting a reduction in microglial activation and suggesting a favorable anti-inflammatory response to minocycline.

Sponsors and collaborators

Lead sponsor

University of Florida

Other

Collaborators

  • National Heart, Lung, and Blood Institute (NHLBI)

Registry information

Official study title

Study 3: Effect of Minocycline Treatment on Drug-Resistant Hypertensive Patients

Important dates

Study start
2016
Primary completion
2018
Study completion
2018
First posted
Aug 11, 2014
Registry last updated
Jul 1, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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