Angiotensin II Blockade and Inflammation in Obesity (ARB)

December 6, 2017 updated by: Kevin Davy, Virginia Polytechnic Institute and State University

Angiotensin II Blockade and Adipose Tissue Inflammation in Obesity

Overweight and obesity, which afflicts ~65% of the U.S. population and more than 1 billion people worldwide, increases the risk of developing hypertension. Activation of the renin angiotensin system (RAS) is an important mechanism by which obesity leads to hypertension. In addition to its vasoconstricting and sodium retaining actions, angiotensin II also has potent pro-inflammatory actions including macrophage infiltration and expression of proinflammatory cytokines in target tissues. Adipose tissue and skeletal muscle appear to be a key sites for the generation of proinflammatory cytokines. Although angiotensin II receptor blockade reduces inflammation in many tissues, the effects on adipose tissue and skeletal muscle in humans are not clear. Importantly, the chronic low grade inflammatory state that accompanies obesity complicates hypertension by contributing to insulin resistance and accelerating cardiovascular disease. Therefore, the general aim of the present proposal will be to determine the influence of angiotensin II receptor blockade on adipose tissue and skeletal muscle inflammation and its relation to improvements in insulin sensitivity, if observed, in obese hypertensive humans. To address these aims, 44 obese (BMI>30 kg/m2) hypertensive (BP>140 systolic and/or 90 diastolic) individuals (age=50-65 years) will be randomized to receive 8 weeks of either the angiotensin II receptor antagonist, olmesartan medoxomil, or no treatment in a crossover manner. Subcutaneous adipose tissue and skeletal muscle biopsies will be obtained and insulin sensitivity (intravenous glucose tolerance tests) will be assessed at baseline and following 8 weeks of each intervention. A two week washout period will separate the interventions.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

20

Phase

  • Phase 4

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 75 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • 18-75 years of age
  • Weight stable for previous 6 months (+2.0kg)
  • Sedentary to recreationally active
  • Willing to be randomized to treatment or placebo
  • Verbal and written informed consent
  • Approved for participation by Medical Director (Jose Rivero, M.D.)

Exclusion Criteria:

  • Blood pressure outside stated range
  • Diabetes or taking diabetes medications
  • Total cholesterol >6.2 mmol/L; triglycerides >4.5 mmol/L
  • Past or current ischemic heart disease, stroke, respiratory disease, endocrine or metabolic disease, neurological disease, or hematological-oncological disease
  • Evidence of renal insufficiency; GFR< 60 ml/min*
  • Medications (including but not limited to antihypertensives, statins or other with anti-inflammatory actions) or antioxidant vitamins or supplements
  • Known allergy or hypersensitivity to olmesartan or any of its components
  • Pregnant or planning to become pregnant

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: Prevention
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Olmesartan Medoxomil first, then No Drug
During the First Intervention (8 weeks), subjects will be provided with daily 20 mg of olmesartan for the first 2 weeks. Subjects receive additional daily doses of 40 mg olmesartan for the remainder of the study period (6 weeks). The dose remains at 20 mg per day, however, if BP falls below 110/70 during the first 2 weeks. In addition, subjects will continue taking the drug during the 2-week follow-up testing period. Subjects will then proceed to the Washout period (2 weeks). During the Second Intervention (8 weeks), no drug will be administered to the subjects.
Drug: Olmesartan medoxomil
Crossover intervention comparing antihypertensive medication to no drug intervention.
Other Names:
  • Benicar
Experimental: No Drug first, then Olmesartan Medoxomil
During the First Intervention (8 weeks), no drug will be administered to the subjects. Subjects will then proceed to the Washout period (2 weeks). During the Second Intervention (8 weeks), subjects will be provided with daily 20 mg of olmesartan for the first 2 weeks. Subjects then receive daily doses of 40 mg olmesartan for the remainder of the study period (6 weeks). The dose remains at 20 mg per day, however, if BP falls below 110/70 during the first 2 weeks. In addition, subjects will continue taking the drug during the 2-week follow-up testing period.
Drug: Olmesartan medoxomil
Crossover intervention comparing antihypertensive medication to no drug intervention.
Other Names:
  • Benicar

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Insulin Sensitivity by Intravenous Glucose Tolerance Testing (Change Over Time)
Time Frame: Baseline testing to post-testing after 8-week intervention
Data collected from the intravenous glucose tolerance tests included blood concentrations of glucose and insulin. Glucose was measured immediately on a YSI glucose analyzer and insulin was measured via ELISA colormetric kits once all study samples were collected. To analyze changes in insulin sensitivity, the MINMOD software was used. The MINMOD software uses Bergman's minimal model to determine insulin sensitivity during an intravenous glucose tolerance test. Both glucose and insulin values were inserted at each timepoint collected (33 in total over the 3-hour protocol) and the software was run to generate the insulin sensitivity value at baseline and post-test. This information was then used to calculate the change of insulin sensitivity from baseline to post-testing after each 8-week intervention.
Baseline testing to post-testing after 8-week intervention

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Collagen Gene Expression in Skeletal Muscle (Change Over Time)
Time Frame: Baseline testing to post-testing after 8-week intervention
RNA extraction and quantification were determined using an RNeasy Mini Fibrous Kit and DNase I treatment (Qiagen, Valencia, CA, USA) in accordance to the manufacturer's directions for mRNA extraction. Quantitative real-time polymerase chain reaction (qRT-PCR) measured the expression of collagen III using an ABI PRISM 7900 Sequence Detection System instrument and TaqMan Universal PCR Master Mix according to the manufacturer's instructions (Applied Biosystems, Foster City, CA, USA). Relative gene expression levels were determined using the number of cycles necessary to reach threshold and results were normalized to cyclophilin B RNA levels.
Baseline testing to post-testing after 8-week intervention

Collaborators and Investigators

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

Sponsor

Virginia Polytechnic Institute and State University

Collaborators

National Heart, Lung, and Blood Institute (NHLBI)

Investigators

  • Principal Investigator: Kevin P. Davy, Ph.D., Virginia Polytechnic Institute and State University

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

February 1, 2009

Primary Completion (Actual)

August 1, 2011

Study Completion (Actual)

August 1, 2011

Study Registration Dates

First Submitted

September 6, 2012

First Submitted That Met QC Criteria

September 10, 2012

First Posted (Estimate)

September 13, 2012

Study Record Updates

Last Update Posted (Actual)

January 3, 2018

Last Update Submitted That Met QC Criteria

December 6, 2017

Last Verified

December 1, 2017

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • arbfat

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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