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Role of Adenosine in the Control of Choroidal Blood Flow During Changes in Ocular Perfusion Pressure.

NCT ID: NCT00712764

Last Updated: 2008-07-10

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

20 participants

Study Classification

INTERVENTIONAL

Study Start Date

2005-01-31

Study Completion Date

2005-04-30

Brief Summary

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Autoregulation is the ability of a vascular bed to maintain blood flow despite changes in perfusion pressure. For a long time it had been assumed that the choroid is a strictly passive vascular bed, which shows no autoregulation. However, recently several groups have identified some autoregulatory capacity of the human choroid. In the brain and the retina the mechanism behind autoregulation is most likely linked to changes in transmural pressure. In this model arterioles change their vascular tone depending on the pressure inside the vessel and outside the vessel. In the choroid, several observations argue against a direct involvement of arterioles. However, the mechanism behind choroidal autoregulation remains unclear. Adenosine, an endogenous purine metabolic end product with a potent vasodilatory effect on multiple vascular beds, leads to an increase in retinal and choroidal vessel diameter. The present study aims to investigate whether adenosine plays a role in choroidal autoregulation during a decrease in ocular perfusion pressure, which will be achieved by an increase in intraocular pressure.

Pressure/flow relationships will be investigated in the absence and presence of adenosine.

Detailed Description

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Conditions

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Ocular Physiology Microcirculation

Keywords

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Adenosine Choroidal blood flow Suction cup

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

CROSSOVER

Primary Study Purpose

TREATMENT

Blinding Strategy

DOUBLE

Participants Investigators

Study Groups

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1

Group Type ACTIVE_COMPARATOR

Adenosine

Intervention Type DRUG

2

Group Type PLACEBO_COMPARATOR

Placebo

Intervention Type DRUG

Interventions

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Adenosine

Intervention Type DRUG

Placebo

Intervention Type DRUG

Eligibility Criteria

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Inclusion Criteria

* Men aged between 18 and 35 years, nonsmokers
* Body mass index between 15th and 85th percentile (Must et al. 1991)
* Normal findings in the medical history and physical examination unless the investigator considers an abnormality to be clinically irrelevant
* Normal laboratory values unless the investigator considers an abnormality to be clinically irrelevant
* Normal ophthalmic findings, ametropia \< 3 Dpt.

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
* Symptoms of a clinically relevant illness in the 3 weeks before the first study day
* History of hypersensitivity to the trial drug or to drugs with a similar chemical structure
* 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
Minimum Eligible Age

18 Years

Maximum Eligible Age

35 Years

Eligible Sex

MALE

Accepts Healthy Volunteers

Yes

Sponsors

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Medical University of Vienna

OTHER

Sponsor Role lead

Responsible Party

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Department of Clinical Pharmacology, Medical University of Vienna

Principal Investigators

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Michael Wolzt, MD

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, , Austria

Site Status

Countries

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Austria

References

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Schmidl D, Weigert G, Dorner GT, Resch H, Kolodjaschna J, Wolzt M, Garhofer G, Schmetterer L. Role of adenosine in the control of choroidal blood flow during changes in ocular perfusion pressure. Invest Ophthalmol Vis Sci. 2011 Jul 29;52(8):6035-9. doi: 10.1167/iovs.11-7491.

Reference Type DERIVED
PMID: 21697134 (View on PubMed)

Other Identifiers

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OPHT-011206

Identifier Type: -

Identifier Source: org_study_id