Role of Endothelin-1 in Optic Nerve Head Blood Flow Regulation During Isometric Exercise in Healthy Humans

August 9, 2012 updated by: Gerhard Garhofer, Medical University of Vienna

Autoregulation is defined as the ability of a vascular bed to adapt its vascular resistance to changes in perfusion pressure. In the eye, several studies have reported that retinal blood flow is autoregulated over a wide range of ocular perfusion pressures. The investigators could recently show that Endothelin-1 is a key metabolite in the regulation of vascular tone in the eye and plays an important role in the blood flow autoregulation of the choroidal circulation. However, no data is yet available for the optic nerve head. Thus, the present study is designed to test the hypothesis that Endothelin-1 plays also a role in optic nerve head blood flow autoregulation.

Therefore, subjects will perform squatting to increase systemic perfusion pressure during administration of either an endothelin A-receptor blocker (BQ-123) or placebo. Optic nerve head blood flow will be continuously measured during the procedure to investigate optic nerve head autoregulation.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

16

Phase

  • Not Applicable

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

  • Austria
      • Vienna, Austria, 1090
        • Department of Clinical Pharmacology, Medical University of Vienna

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 35 years (Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Men and women aged between 18 and 35 years, nonsmokers
  • Men and women will be included in equal parts
  • Normal findings in the medical history and physical examination unless the investigator considers an abnormality to be clinically irrelevant
  • Normal findings in the laboratory testings unless the investigator considers an abnormality to be clinically irrelevant
  • Normal ophthalmic findings, ametropia less than 3 diopters

Exclusion Criteria:

  • Regular use of medication, abuse of alcoholic beverages, participation in a clinical trial in the 3 weeks preceding the study
  • Treatment in the previous 3 weeks with any drug (except intake of oral contraceptives)
  • Symptoms of a clinically relevant illness in the 3 weeks before the first study day
  • History or presence of gastrointestinal, liver or kidney disease, or other conditions known to interfere with distribution, metabolism or excretion of study drugs
  • Blood donation during the previous 3 weeks
  • Pregnancy

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: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Placebo Comparator: Physiological saline solution
Drug: BQ-123
60 mcg/min, infusion period: 60 min
Drug: Physiological saline solution
infusion period 60 minutes
Device: Laser Doppler Flowmetry
blood flow measurements at the temporal neuroretinal rim to assess optic nerve head blood flow
Device: Goldmann Applanation Tonometer
intraocular pressure measurements
Other: squatting
subjects will perform squatting for 6 minutes while blood flow measurements
Active Comparator: BQ-123
Drug: BQ-123
60 mcg/min, infusion period: 60 min
Drug: Physiological saline solution
infusion period 60 minutes
Device: Laser Doppler Flowmetry
blood flow measurements at the temporal neuroretinal rim to assess optic nerve head blood flow
Device: Goldmann Applanation Tonometer
intraocular pressure measurements
Other: squatting
subjects will perform squatting for 6 minutes while blood flow measurements

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Optic nerve head pressure-flow relationship
Time Frame: 1 year
1 year

Collaborators and Investigators

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

Sponsor

Medical University of Vienna

Investigators

  • Principal Investigator: Gabriele Fuchsjaeger-Mayrl, MD, Univ.Doz, Department of Clinical Pharmacology, Medical University of Vienna

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

October 1, 2010

Primary Completion (Actual)

May 1, 2011

Study Completion (Actual)

December 1, 2011

Study Registration Dates

First Submitted

June 1, 2009

First Submitted That Met QC Criteria

June 4, 2009

First Posted (Estimate)

June 5, 2009

Study Record Updates

Last Update Posted (Estimate)

August 10, 2012

Last Update Submitted That Met QC Criteria

August 9, 2012

Last Verified

August 1, 2012

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • OPHT-320708

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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