Ocular PhysiologyPhase 2NCT00406731
Role of Endothelin- and Nitric Oxide-system in the Regulation of Optic Nerve Head Blood Flow During Changes in Ocular Perfusion Pressure
A Phase 2 study testing NG-monomethyl-L-arginine (L-NMMA), Endothelin-1 (ET-1) and Laser Doppler flowmetry in people with Ocular Physiology and Optic Disk, run by Medical University of Vienna at 1 site in Austria.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 to 35 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Ocular Physiology, Optic Disk, Regional Blood Flow
- What is being tested?
- NG-monomethyl-L-arginine (L-NMMA), Endothelin-1 (ET-1) and Laser Doppler flowmetry
- Type of treatment
- Injection or infusion, Medical device, Surgery or procedure
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 0 participants
- Where
- 1 siteAustria
- Study dates
- Jan 2008to Nov 2014
- Phase
- Phase 2
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 35 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- 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
Who cannot join
- 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
Trial locations and contacts
1 site in 1 country.
Austria1 site
Department of Clinical Pharmacology, Medical University of Vienna
Vienna, 1090
About this study
Official title: Role of endothelin-and Nitric Oxide-system in the Regulation of Optic Nerve Head Blood Flow During Changes in Ocular Perfusion Pressure
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).
- Conditions
- Ocular Physiology, Optic Disk, Regional Blood Flow
- Being tested
- NG-monomethyl-L-arginine (L-NMMA), Endothelin-1 (ET-1), Physiologic saline solution (placebo control), Laser Doppler flowmetry, Goldmann applanation tonometer
- Keywords
- Endothelin-1, L-NG-Monomethyl Arginine, Optic Nerve Head blood flow
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
NG-monomethyl-L-arginine (L-NMMA)Drug
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
Endothelin-1 (ET-1)Drug
5 ng/kg/min intravenous infusion over 17 minutes; twice on 1 study day
Physiologic saline solution (placebo control)Drug
intravenous infusion over 20 minutes; twice on 1 study day
Laser Doppler flowmetryDevice
blood flow measurements at the temporal neuroretinal rim of the optic nerve head
Goldmann applanation tonometerDevice
Intraocular pressure measurements
HP-CMS patient monitorDevice
blood pressure and pulse rate measurements
Suction cup methodProcedure or surgery
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.
What is being measured
The primary outcome is the main question the study is designed to answer.
ONH pressure-flow relationship
Measured: up to 3 study days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted4 Dec 2006 (estimated)
- Study startJan 2008
- Primary completionNov 2014
- Study completionNov 2014
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Ocular PhysiologyStudies of the same condition, open and under way.
- More trials run by Medical University of ViennaThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 0 participants (actual)
Sponsor and investigators
- Lead sponsor
- Medical University of Vienna
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Gerhard Garhofer, Medical University of Vienna
- Investigators
- Gabriele Fuchsjaeger-Mayrl, MD,Univ.Doz., Principal investigator, Department of Clinical Pharmacology, Medical University of Vienna
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00406731
- Sponsor's protocol ID
- OPHT-080206
- Status last verified
- Aug 2019
- First submitted
- 30 Nov 2006
- Last updated
- 15 Aug 2019
- Results posted
- No
- Data monitoring committee
- Yes
Study at a glance
From the registry record, last updated by the sponsor on 15 Aug 2019. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Role of endothelin-and Nitric Oxide-system in the Regulation of Optic Nerve Head Blood Flow During Changes in Ocular Perfusion Pressure
- ClinicalTrials.gov ID
- NCT00406731
- Acronym / sponsor ID
- OPHT-080206
- Conditions
- Ocular Physiology, Optic Disk, Regional Blood Flow
- Keywords
- Endothelin-1, L-NG-Monomethyl Arginine, Optic Nerve Head blood flow
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Withdrawn
- Enrolment
- 0 participants (actual)
- Lead sponsor
- Medical University of ViennaUniversity, hospital or other
- Study start
- Jan 2008
- Primary completion
- Nov 2014 (actual)
- Study completion
- Nov 2014 (actual)
- First posted
- 4 Dec 2006 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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).
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind (participant, investigator, outcomes assessor)
Who may qualify
- Ages
- 18 to 35 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (5 listed)
- 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
Key exclusion criteria (7 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| 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 | Drug | – |
| Laser Doppler flowmetryblood flow measurements at the temporal neuroretinal rim of the optic nerve head | Device | – |
| Goldmann applanation tonometerIntraocular pressure measurements | Device | – |
| HP-CMS patient monitorblood pressure and pulse rate measurements | Device | – |
| Suction cup methodThe 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. | Procedure or surgery | – |
Primary outcome
ONH pressure-flow relationship
Time frame: up to 3 study days
Results and safety
The study was withdrawn before enrolling participants, so there are no results.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 15 Aug 2019.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Gabriele Fuchsjaeger-Mayrl, MD,Univ.Doz. principal investigator
Department of Clinical Pharmacology, Medical University of Vienna
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing NG-monomethyl-L-arginine (L-NMMA), Endothelin-1 (ET-1) and Laser Doppler flowmetry in people with Ocular Physiology and Optic Disk, run by Medical University of Vienna at 1 site in Austria.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: withdrawn, as of the sponsor's last update on 15 Aug 2019. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Austria. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study was withdrawn before enrolling participants, so there are no results.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
ONH pressure-flow relationship (time frame: up to 3 study days). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 15 Aug 2019.