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

This study has been completed.
Sponsor:
Information provided by (Responsible Party):
Gerhard Garhofer, Medical University of Vienna
ClinicalTrials.gov Identifier:
NCT00915070
First received: June 1, 2009
Last updated: August 9, 2012
Last verified: August 2012

June 1, 2009
August 9, 2012
October 2010
May 2011   (final data collection date for primary outcome measure)
Optic nerve head pressure-flow relationship [ Time Frame: 1 year ] [ Designated as safety issue: No ]
Same as current
Complete list of historical versions of study NCT00915070 on ClinicalTrials.gov Archive Site
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Role of Endothelin-1 in Optic Nerve Head Blood Flow Regulation During Isometric Exercise in Healthy Humans
Role of Endothelin-1 in Optic Nerve Head Blood Flow Regulation During Isometric Exercise in Healthy Humans

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.

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Interventional
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Allocation: Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Crossover Assignment
Masking: Double Blind (Subject, Investigator, Outcomes Assessor)
Primary Purpose: Basic Science
Healthy
  • 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
    Interventions:
    • Drug: BQ-123
    • Drug: Physiological saline solution
    • Device: Laser Doppler Flowmetry
    • Device: Goldmann Applanation Tonometer
    • Other: squatting
  • Placebo Comparator: Physiological saline solution
    Interventions:
    • Drug: BQ-123
    • Drug: Physiological saline solution
    • Device: Laser Doppler Flowmetry
    • Device: Goldmann Applanation Tonometer
    • Other: squatting
Not Provided

*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Completed
16
December 2011
May 2011   (final data collection date for primary outcome measure)

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
Both
18 Years to 35 Years
Yes
Contact information is only displayed when the study is recruiting subjects
Austria
 
NCT00915070
OPHT-320708
Yes
Gerhard Garhofer, Medical University of Vienna
Medical University of Vienna
Not Provided
Principal Investigator: Gabriele Fuchsjaeger-Mayrl, MD, Univ.Doz Department of Clinical Pharmacology, Medical University of Vienna
Medical University of Vienna
August 2012

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP