HealthyNCT00806741
Role of Nitric Oxide in Optic Nerve Head Blood Flow Regulation During Isometric Exercise in Healthy Humans
A study testing NG-monomethyl-L-arginine (L-NMMA), Phenylephrine and Laser Doppler Flowmetry in people with Healthy, run by Medical University of Vienna at 1 site in Austria.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 to 35 yearsHealthy volunteers can take part
- Conditions the study is for
- Healthy
- What is being tested?
- NG-monomethyl-L-arginine (L-NMMA), Phenylephrine and Laser Doppler Flowmetry
- Type of treatment
- Injection or infusion, Medical device
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 18 participants
- Where
- 1 siteAustria
- Study dates
- Sep 2009to Sep 2012
- Phase
- Interventional
- 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
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- 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
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 (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
Trial locations and contacts
1 site in 1 country.
Austria1 site
Department of Clinical Pharmacology, Medical University of Vienna
Vienna, 1090
About this study
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 recently showed that nitric oxide (NO) 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 NO 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 a nitric oxide synthase inhibitor (L-NMMA), an α-receptor agonist (phenylephrine) or placebo. Optic nerve head blood flow will be continuously measured during the procedure to investigate optic nerve head autoregulation.
- Conditions
- Healthy
- Being tested
- NG-monomethyl-L-arginine (L-NMMA), Phenylephrine, Physiological saline solution (as placebo), Laser Doppler Flowmetry, Goldmann applanation tonometer
- Keywords
- L-NG-Monomethyl Arginine, Optic Nerve Head blood flow, Intraocular Pressure, Regional blood flow, Ocular Physiology, Optic Disk
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 6mg/kg over 5 minutes followed by a continuous infusion of 60µg/kg/min over 15 minutes
PhenylephrineDrug
1μg/kg/min, infusion period 20 minutes
Physiological saline solution (as placebo)Drug
infusion period 20 minutes
Laser Doppler FlowmetryDevice
blood flow measurements at the temporal neuroretinal rim of the optic nerve head
Goldmann applanation tonometerDevice
intraocular pressure measurements
squattingOther
Subjects will perform squatting for 6 minutes while blood flow is measured
| Study group | Role | What they receive |
|---|---|---|
| 1 | Active comparator | NG-monomethyl-L-arginine (L-NMMA) Receives: Drug: NG-monomethyl-L-arginine (L-NMMA); Device: Laser Doppler Flowmetry; Device: Goldmann applanation tonometer; Other: squatting |
| 2 | Active comparator | Phenylephrine Receives: Drug: Phenylephrine; Device: Laser Doppler Flowmetry; Device: Goldmann applanation tonometer; Other: squatting |
| 3 | Placebo comparator | Physiological saline solution Receives: Drug: Physiological saline solution (as placebo); Device: Laser Doppler Flowmetry; Device: Goldmann applanation tonometer; Other: squatting |
What is being measured
The primary outcome is the main question the study is designed to answer.
Optic nerve head pressure-flow relationship
Measured: in total 6x on 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 posted11 Dec 2008 (estimated)
- Study startSep 2009
- Primary completionMar 2010
- Study completionSep 2012
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for HealthyStudies 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 N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 18 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, Medical University of Vienna
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00806741
- Sponsor's protocol ID
- OPHT-300708
- Status last verified
- Nov 2012
- First submitted
- 10 Dec 2008
- Last updated
- 30 Nov 2012
- Results posted
- No
- Data monitoring committee
- Yes
Publications
Schmidl D, Boltz A, Kaya S, Lasta M, Pemp B, Fuchsjager-Mayrl G, Hommer A, Garhofer G, Schmetterer L. Role of nitric oxide in optic nerve head blood flow regulation during isometric exercise in healthy humans. Invest Ophthalmol Vis Sci. 2013 Mar 15;54(3):1964-70. doi: 10.1167/iovs.12-11406.
PubMed 23439596
Study at a glance
From the registry record, last updated by the sponsor on 30 Nov 2012. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Role of Nitric Oxide in Optic Nerve Head Blood Flow Regulation During Isometric Exercise in Healthy Humans
- ClinicalTrials.gov ID
- NCT00806741
- Acronym / sponsor ID
- OPHT-300708
- Conditions
- Healthy
- Keywords
- L-NG-Monomethyl Arginine, Optic Nerve Head blood flow, Intraocular Pressure, Regional blood flow, Ocular Physiology, Optic Disk
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 18 participants (actual)
- Lead sponsor
- Medical University of ViennaUniversity, hospital or other
- Study start
- Sep 2009
- Primary completion
- Mar 2010 (actual)
- Study completion
- Sep 2012 (actual)
- First posted
- 11 Dec 2008 (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 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 recently showed that nitric oxide (NO) 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 NO 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 a nitric oxide synthase inhibitor (L-NMMA), an α-receptor agonist (phenylephrine) or placebo. Optic nerve head blood flow will be continuously measured during the procedure to investigate optic nerve head autoregulation.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| 1 | Active comparator | Drug: NG-monomethyl-L-arginine (L-NMMA), Device: Laser Doppler Flowmetry, Device: Goldmann applanation tonometer, Other: squattingNG-monomethyl-L-arginine (L-NMMA) |
| 2 | Active comparator | Drug: Phenylephrine, Device: Laser Doppler Flowmetry, Device: Goldmann applanation tonometer, Other: squattingPhenylephrine |
| 3 | Placebo comparator | Drug: Physiological saline solution (as placebo), Device: Laser Doppler Flowmetry, Device: Goldmann applanation tonometer, Other: squattingPhysiological saline solution |
Who may qualify
- Ages
- 18 to 35 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (5 listed)
- 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
Key exclusion criteria (6 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 (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
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 6mg/kg over 5 minutes followed by a continuous infusion of 60µg/kg/min over 15 minutes | Drug | 1 |
| Phenylephrine1μg/kg/min, infusion period 20 minutes | Drug | 2 |
| Physiological saline solution (as placebo)infusion period 20 minutes | Drug | 3 |
| Laser Doppler Flowmetryblood flow measurements at the temporal neuroretinal rim of the optic nerve head | Device | 1, 2, 3 |
| Goldmann applanation tonometerintraocular pressure measurements | Device | 1, 2, 3 |
| squattingSubjects will perform squatting for 6 minutes while blood flow is measured | Other | 1, 2, 3 |
Primary outcome
Optic nerve head pressure-flow relationship
Time frame: in total 6x on 3 study days
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 30 Nov 2012.
- Derived from this study: PubMed 23439596Schmidl D, Boltz A, Kaya S, Lasta M, Pemp B, Fuchsjager-Mayrl G, Hommer A, Garhofer G, Schmetterer L. Role of nitric oxide in optic nerve head blood flow regulation during isometric exercise in healthy humans. Invest Ophthalmol Vis Sci. 2013 Mar 15;54(3):1964-70. doi: 10.1167/iovs.12-11406.
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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
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 study testing NG-monomethyl-L-arginine (L-NMMA), Phenylephrine and Laser Doppler Flowmetry in people with Healthy, 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 6 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: finished, as of the sponsor's last update on 30 Nov 2012. 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. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
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?
Optic nerve head pressure-flow relationship (time frame: in total 6x on 3 study days). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT00806741, which also lists 1 linked publication.
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 30 Nov 2012.