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

NCT00712764 | Completed DMC

• 1 other identifier: OPHT-011206
• Study Type: interventional
• Target: 20
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Ocular Physiology; Microcirculation

Keywords

Adenosine; Choroidal blood flow; Suction cup

Outcome Measures

Primary Outcomes (1)

• choroidal pressure-flow relationship

  2 hours at 2 study days

Study Arms (2)

1

ACTIVE COMPARATOR

Drug: Adenosine

2

PLACEBO COMPARATOR

Drug: Placebo

Interventions

Adenosine DRUG

1

Placebo DRUG

2

Eligibility Criteria

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

You may qualify if:

• 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.

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
• 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

Sponsors & Collaborators

• Medical University of Vienna: lead

Study Sites (1)

Department of Clinical Pharmacology, Medical University of Vienna

Vienna, 1090, Austria

Location

Related Publications (1)

• 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.

  PMID: 21697134 DERIVED

MeSH Terms

Interventions

Adenosine

Intervention Hierarchy (Ancestors)

Purine Nucleosides; Purines; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring; Heterocyclic Compounds; Nucleosides; Nucleic Acids, Nucleotides, and Nucleosides; Ribonucleosides

Study Officials

• Michael Wolzt, MD

  Department of Clinical Pharmacology, Medical University of Vienna

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Purpose: TREATMENT
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER

Study Record Dates

• First Submitted: July 8, 2008
• First Posted: July 10, 2008
• Study Start: January 1, 2005
• Primary Completion: April 1, 2005
• Study Completion: April 1, 2005
• Last Updated: July 10, 2008

Record last verified: 2006-12

Locations

AU (1)