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Role of Endothelin- and Nitric Oxide-system in the Regulation of Optic Nerve Head Blood Flow During Changes in Ocular Perfusion Pressure

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ClinicalTrials.gov Identifier: NCT00406731
Recruitment Status : Withdrawn
First Posted : December 4, 2006
Last Update Posted : August 15, 2019
Sponsor:
Information provided by (Responsible Party):
Gerhard Garhofer, Medical University of Vienna

Tracking Information
First Submitted Date  ICMJE November 30, 2006
First Posted Date  ICMJE December 4, 2006
Last Update Posted Date August 15, 2019
Study Start Date  ICMJE January 2008
Actual Primary Completion Date November 2014   (Final data collection date for primary outcome measure)
Current Primary Outcome Measures  ICMJE
 (submitted: November 20, 2014)
ONH pressure-flow relationship [ Time Frame: up to 3 study days ]
Original Primary Outcome Measures  ICMJE
 (submitted: November 30, 2006)
ONH pressure-flow relationship
Change History
Current Secondary Outcome Measures  ICMJE Not Provided
Original Secondary Outcome Measures  ICMJE Not Provided
Current Other Pre-specified Outcome Measures Not Provided
Original Other Pre-specified Outcome Measures Not Provided
 
Descriptive Information
Brief Title  ICMJE Role of Endothelin- and Nitric Oxide-system in the Regulation of Optic Nerve Head Blood Flow During Changes in Ocular Perfusion Pressure
Official Title  ICMJE Role of endothelin-and Nitric Oxide-system in the Regulation of Optic Nerve Head Blood Flow During Changes in Ocular Perfusion Pressure
Brief Summary

Autoregulation is the ability of a vascular bed to maintain blood flow despite changes in perfusion pressure. The existence of an effective autoregulation in the optic nerve circulation has been shown in animals and humans. The exact mechanism behind this autoregulation is still unknown. The motive for the investigation of optic nerve head (ONH) blood flow autoregulation is to enhance the understanding of pathologic eye conditions associated with ocular vascular disorders. To clarify the regulatory mechanisms of ONH microcirculation is of critical importance to understand the pathophysiology of glaucoma because there is evidence that glaucoma is associated with optic nerve head ischemia. Several studies indicate that a disturbed autoregulation might contribute to glaucomatous optic neuropathy. Previous findings suggest endothelial dysfunction in glaucomatous optic neuropathy, in particular alterations in endothelin- and nitric oxide- system, which both play an important role in local regulation of vascular tone.

In the present study, changes in ocular perfusion pressure will be performed during administration of drugs, which may potentially alter the pressure-flow relationship. These drugs include endothelin-1 and the nitric oxide synthase inhibitor NG-monomethyl-L-arginine (L-NMMA).

Detailed Description Not Provided
Study Type  ICMJE Interventional
Study Phase  ICMJE Phase 2
Study Design  ICMJE Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Condition  ICMJE
  • Ocular Physiology
  • Optic Disk
  • Regional Blood Flow
Intervention  ICMJE
  • Drug: NG-monomethyl-L-arginine (L-NMMA)
    bolus 6 mg/kg over 5 minutes followed by a continuous intravenous infusion of 60 µg/kg/min over 12 minutes; twice on 1 study day
  • Drug: Endothelin-1 (ET-1)
    5 ng/kg/min intravenous infusion over 17 minutes; twice on 1 study day
  • Drug: Physiologic saline solution (placebo control)
    intravenous infusion over 20 minutes; twice on 1 study day
  • Device: Laser Doppler flowmetry
    blood flow measurements at the temporal neuroretinal rim of the optic nerve head
  • Device: Goldmann applanation tonometer
    Intraocular pressure measurements
  • Device: HP-CMS patient monitor
    blood pressure and pulse rate measurements
  • Procedure: Suction cup method
    The IOP will be raised by an 11 mm diameter, standardized suction cup placed on the temporal sclera with the anterior edge at least 1 mm from the limbus.
Study Arms  ICMJE Not Provided
Publications * Not Provided

*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Recruitment Information
Recruitment Status  ICMJE Withdrawn
Actual Enrollment  ICMJE
 (submitted: November 20, 2014)
0
Original Enrollment  ICMJE
 (submitted: November 30, 2006)
18
Actual Study Completion Date  ICMJE November 2014
Actual Primary Completion Date November 2014   (Final data collection date for primary outcome measure)
Eligibility Criteria  ICMJE

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, ametropy < 1 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 systemic or pulmonary hypertension, or other cardiac or pulmonary diseases
  • 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
Sex/Gender  ICMJE
Sexes Eligible for Study: Male
Ages  ICMJE 18 Years to 35 Years   (Adult)
Accepts Healthy Volunteers  ICMJE Yes
Contacts  ICMJE Contact information is only displayed when the study is recruiting subjects
Listed Location Countries  ICMJE Austria
Removed Location Countries  
 
Administrative Information
NCT Number  ICMJE NCT00406731
Other Study ID Numbers  ICMJE OPHT-080206
Has Data Monitoring Committee Yes
U.S. FDA-regulated Product Not Provided
IPD Sharing Statement  ICMJE Not Provided
Current Responsible Party Gerhard Garhofer, Medical University of Vienna
Original Responsible Party Not Provided
Current Study Sponsor  ICMJE Medical University of Vienna
Original Study Sponsor  ICMJE Same as current
Collaborators  ICMJE Not Provided
Investigators  ICMJE
Principal Investigator: Gabriele Fuchsjaeger-Mayrl, MD,Univ.Doz. Department of Clinical Pharmacology, Medical University of Vienna
PRS Account Medical University of Vienna
Verification Date August 2019

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