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

NCT00915070 | Completed DMC

• 1 other identifier: OPHT-320708
• Study Type: interventional
• Target: 16
• Locations: 1 country
• Sites: 1

Brief 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.

Conditions

Healthy

Keywords

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

Outcome Measures

Primary Outcomes (1)

• Optic nerve head pressure-flow relationship

  1 year

Study Arms (2)

BQ-123

ACTIVE COMPARATOR

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

Physiological saline solution

PLACEBO COMPARATOR

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

Interventions

BQ-123 DRUG

60 mcg/min, infusion period: 60 min

BQ-123; Physiological saline solution

Physiological saline solution DRUG

infusion period 60 minutes

BQ-123; Physiological saline solution

Laser Doppler Flowmetry DEVICE

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

BQ-123; Physiological saline solution

Goldmann Applanation Tonometer DEVICE

intraocular pressure measurements

BQ-123; Physiological saline solution

squatting OTHER

subjects will perform squatting for 6 minutes while blood flow measurements

BQ-123; Physiological saline solution

Eligibility Criteria

• Age: 18 Years - 35 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• Medical University of Vienna: lead

Study Sites (1)

Department of Clinical Pharmacology, Medical University of Vienna

Vienna, Vienna, 1090, Austria

Location

MeSH Terms

Interventions

cyclo(Trp-Asp-Pro-Val-Leu); Laser-Doppler Flowmetry

Intervention Hierarchy (Ancestors)

Diagnostic Techniques, Cardiovascular; Diagnostic Techniques and Procedures; Diagnosis; Rheology; Investigative Techniques

Study Officials

• Gabriele Fuchsjaeger-Mayrl, MD, Univ.Doz

  Department of Clinical Pharmacology, Medical University of Vienna

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Ass.Prof.Priv.Doz.Dr.

Study Record Dates

• First Submitted: June 1, 2009
• First Posted: June 5, 2009
• Study Start: October 1, 2010
• Primary Completion: May 1, 2011
• Study Completion: December 1, 2011
• Last Updated: August 10, 2012

Record last verified: 2012-08

Locations

AU (1)