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

Sponsored by:	Medical University of Vienna
Information provided by:	Medical University of Vienna
ClinicalTrials.gov Identifier:	NCT00915070

Purpose

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.

Condition	Intervention
Healthy	Drug: BQ-123 Drug: Physiological saline solution Device: Laser Doppler Flowmetry Device: Goldmann Applanation Tonometer Other: squatting

Study Type:	Interventional
Study Design:	Basic Science, Randomized, Double Blind (Subject, Investigator, Outcomes Assessor), Placebo Control, Crossover Assignment, Safety/Efficacy Study
Official Title:	Role of Endothelin-1 in Optic Nerve Head Blood Flow Regulation During Isometric Exercise in Healthy Humans

Resource links provided by NLM:

MedlinePlus related topics: Exercise and Physical Fitness

Drug Information available for: BQ 123

U.S. FDA Resources

Further study details as provided by Medical University of Vienna:

Primary Outcome Measures:

Optic nerve head pressure-flow relationship [ Time Frame: 1 year ] [ Designated as safety issue: No ]

Estimated Enrollment:	24
Study Start Date:	July 2009
Estimated Primary Completion Date:	July 2010 (Final data collection date for primary outcome measure)

Arms	Assigned Interventions
BQ-123: Active Comparator	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
Physiological saline solution: Placebo Comparator	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

Arms

Assigned Interventions

BQ-123: Active Comparator

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

Physiological saline solution: Placebo Comparator

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

Eligibility

Ages Eligible for Study:	18 Years to 35 Years
Genders Eligible for Study:	Both
Accepts Healthy Volunteers:	Yes

Criteria

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

Contacts and Locations

Please refer to this study by its ClinicalTrials.gov identifier: NCT00915070

Contacts

Contact: Gerhard Garhoefer, MD, Priv-Doz.

0043 1 40400 ext 2981

gerhard.garhoefer@meduniwien.ac.at

Locations

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

Sponsors and Collaborators

Medical University of Vienna

Investigators

Principal Investigator:

Gabriele Fuchsjaeger-Mayrl, MD, Univ.Doz

Department of Clinical Pharmacology, Medical University of Vienna

More Information

No publications provided

Responsible Party:	Department of Clinical Pharmacology, Medical University of Vienna ( Gabriele Fuchsjaeger-Mayrl, MD )
Study ID Numbers:	OPHT-320708
Study First Received:	June 1, 2009
Last Updated:	June 4, 2009
ClinicalTrials.gov Identifier:	NCT00915070 History of Changes
Health Authority:	Austria: Agency for Health and Food Safety

Keywords provided by Medical University of Vienna:

BQ-123
Optic Nerve Head Blood Flow
Intraocular Pressure

Regional Blood Flow
Ocular Physiology
Optic Disk

Study placed in the following topic categories:

Cyclo(Trp-Asp-Pro-Val-Leu)
Healthy

ClinicalTrials.gov processed this record on September 03, 2009