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

Healthy Clinical Trial

Official title:

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

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT00915070
• Other study ID #: OPHT-320708
• Status: Completed
• Phase: N/A
• First received: June 1, 2009
• Last updated: August 9, 2012
• Start date: October 2010
• Est. completion date: December 2011

Study information

• Verified date: August 2012
• Source: Medical University of Vienna
• Contact: n/a
• Is FDA regulated: No
• Health authority: Austria: Agency for Health and Food Safety
• Study type: Interventional

Clinical Trial Summary

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 16
• Est. completion date: December 2011
• Est. primary completion date: May 2011
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Both
• Age group: 18 Years to 35 Years

Eligibility

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 Design

Allocation: Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Crossover Assignment, Masking: Double Blind (Subject, Investigator, Outcomes Assessor), Primary Purpose: Basic Science

Related Conditions & MeSH terms

• Healthy

Intervention

Drug:
• BQ-123
60 mcg/min, infusion period: 60 min
• 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
• Goldmann Applanation Tonometer
intraocular pressure measurements

Other:
• squatting
subjects will perform squatting for 6 minutes while blood flow measurements

Locations

Country	Name	City	State
Austria	Department of Clinical Pharmacology, Medical University of Vienna	Vienna

Sponsors (1)

Lead Sponsor	Collaborator
Medical University of Vienna

Country where clinical trial is conducted

Austria, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Optic nerve head pressure-flow relationship		1 year	No