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

NCT ID: NCT00915070

Last Updated: 2012-08-10

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

NA

Total Enrollment

16 participants

Study Classification

INTERVENTIONAL

Study Start Date

2010-10-31

Study Completion Date

2011-12-31

Brief Summary

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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.

Detailed Description

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Conditions

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Healthy

Keywords

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BQ-123 Optic Nerve Head Blood Flow Intraocular Pressure Regional Blood Flow Ocular Physiology Optic Disk

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

CROSSOVER

Primary Study Purpose

BASIC_SCIENCE

Blinding Strategy

TRIPLE

Participants Investigators Outcome Assessors

Study Groups

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BQ-123

Group Type ACTIVE_COMPARATOR

BQ-123

Intervention Type DRUG

60 mcg/min, infusion period: 60 min

Physiological saline solution

Intervention Type DRUG

infusion period 60 minutes

Laser Doppler Flowmetry

Intervention Type DEVICE

blood flow measurements at the temporal neuroretinal rim to assess optic nerve head blood flow

Goldmann Applanation Tonometer

Intervention Type DEVICE

intraocular pressure measurements

squatting

Intervention Type OTHER

subjects will perform squatting for 6 minutes while blood flow measurements

Physiological saline solution

Group Type PLACEBO_COMPARATOR

BQ-123

Intervention Type DRUG

60 mcg/min, infusion period: 60 min

Physiological saline solution

Intervention Type DRUG

infusion period 60 minutes

Laser Doppler Flowmetry

Intervention Type DEVICE

blood flow measurements at the temporal neuroretinal rim to assess optic nerve head blood flow

Goldmann Applanation Tonometer

Intervention Type DEVICE

intraocular pressure measurements

squatting

Intervention Type OTHER

subjects will perform squatting for 6 minutes while blood flow measurements

Interventions

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BQ-123

60 mcg/min, infusion period: 60 min

Intervention Type DRUG

Physiological saline solution

infusion period 60 minutes

Intervention Type DRUG

Laser Doppler Flowmetry

blood flow measurements at the temporal neuroretinal rim to assess optic nerve head blood flow

Intervention Type DEVICE

Goldmann Applanation Tonometer

intraocular pressure measurements

Intervention Type DEVICE

squatting

subjects will perform squatting for 6 minutes while blood flow measurements

Intervention Type OTHER

Eligibility Criteria

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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
Minimum Eligible Age

18 Years

Maximum Eligible Age

35 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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Medical University of Vienna

OTHER

Sponsor Role lead

Responsible Party

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Gerhard Garhofer

Ass.Prof.Priv.Doz.Dr.

Responsibility Role PRINCIPAL_INVESTIGATOR

Principal Investigators

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Gabriele Fuchsjaeger-Mayrl, MD, Univ.Doz

Role: PRINCIPAL_INVESTIGATOR

Department of Clinical Pharmacology, Medical University of Vienna

Locations

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Department of Clinical Pharmacology, Medical University of Vienna

Vienna, Vienna, Austria

Site Status

Countries

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Austria

Other Identifiers

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OPHT-320708

Identifier Type: -

Identifier Source: org_study_id