HealthyPhase 1NCT00105222
Effect of Nitrite on Exercise Physiology and Metabolism
A Phase 1 study testing Sodium Nitrite in people with Healthy and Healthy Volunteer, run by National Heart, Lung, and Blood Institute (NHLBI) at 1 site in United States.
Trial summary
This study will examine how nitrite infusions affect exercise tolerance (how much a person can exercise before having to stop). Exercise ability is limited by how fast oxygen can be delivered to the body and how fast the body can produce energy. Read more about this study
- Who is it for?
- Ages 21 to 45 years
- Conditions the study is for
- Healthy, Healthy Volunteer, HV
- What is being tested?
- Sodium Nitrite
- How many people
- 15 participants
- Where
- 1 siteUnited States
- Study dates
- 8 Mar 2005to 16 Aug 2013
- Phase
- Phase 1
- 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 21 to 45 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- Subjects must be 21-45 years of age.
- Subject must be in good health and able to perform cycle ergometry for the length of the study.
- Subjects must provide informed, written consent for participation in this study.
- Female subjects of childbearing age must have a negative pregnancy test.
Who cannot join
- Subjects with a history of cardiac, pulmonary, peripheral vascular, or mitochondrial disease.
- Subjects with abnormal EKG other than sinus bradycardia.
- Individuals with a future cardiovascular risk greater than 1 % in the next 10 years will be excluded from the study. Risk will be calculated using the Framingham risk calculator published on the web site: http://hin.nhlbi.nih.gov/atpiii/calculator.asp?usertype=prof.
- Subjects with any physical condition (for example, knee problems) that may impair their performance during exercise testing.
- Subjects who have a history of smoking within one year.
- Subjects with anemia (defined as hemoglobin less than 10 g/dL).
Show all 12Show fewer
- Subjects with a history of reaction to a medication or other substance characterized by dyspnea and cyanosis will not participate in this study.
- Subjects with G6PD deficiency.
- Subjects with a baseline methemoglobin level greater than 1%.
- Lactating females who are breastfeeding, will not participate since nitrite crosses into breast milk and could cause methemoglobinemia in the infant.
- No volunteer subject will be allowed to take any medication (oral contraceptive agents are allowed), vitamin supplements, herbal preparations, nutriceuticals or other alternative therapies for at least one month prior to study and will not be allowed to take aspirin or NSAIDs for one week prior to study.
- Subjects with a blood pressure of less than 100/70 mmHg on the study day will be excluded from the protocol.
Trial locations and contacts
1 site in 1 country.
United States1 site
National Institutes of Health Clinical Center, 9000 Rockville Pike
Bethesda, Maryland, 20892
About this study
Official title: Evaluation of Systemic Nitrite Infusion and Its Effect on Exercise Physiology and Metabolism
This study will examine how nitrite infusions affect exercise tolerance (how much a person can exercise before having to stop). Exercise ability is limited by how fast oxygen can be delivered to the body and how fast the body can produce energy. Both of these processes are affected by nitric oxide (NO), a gas produced by cells that line blood vessels. NO is important in regulating blood vessel dilation, and consequently, blood flow. Nitrite may act as a storehouse for nitric oxide and be able to improve exercise tolerance.
Healthy normal volunteers between 21 and 45 years of age who can use an exercise bicycle may be eligible for this study. Candidates are screened with a medical history, physical examination, electrocardiogram, breathing tests, blood tests, and a pregnancy test for women who are able to bear children. Pregnant women are excluded from the study. The screening session includes practice exercise on the bicycle.
Read more
Participants exercise on a stationery exercise bicycle for about 30 minutes on each of two study days. During the test, they breathe in and out of a mouthpiece that allows inhaled and exhaled respiratory gases to be measured. Before subjects begin to exercise, a small tube is placed in the artery of their forearm inside the elbow. A longer tube called a central line is placed in a deeper vein in the neck after the area has been numbed. A thinner tube, called a pulmonary artery catheter, is placed through the central line and advanced into the chambers of the heart, through the heart valve, and into the lung artery. This catheter measures various pressures directly in the heart and lungs. Blood samples are drawn through the catheter also, to avoid the need for multiple needle sticks. Another tube is placed in the vein of the other arm to deliver medications.
Thirty minutes after all the tubes are placed, a blood sample is drawn for baseline measurements. Then, either saline (sterile salt water) or nitrite is injected into the tube in the arm vein. Thirty minutes after the injection, the subject starts exercising on the bicycle. The work setting on the bicycle is increased every minute, and the subject pedals until he or she is too tired to continue. During the test, a small blood sample is collected every 2 minutes. Heart rate, blood pressure, and heart rhythms are continuously monitored.
After the test on the first day, participants are admitted to the hospital to rest for the remainder of the afternoon and evening. The tubes are kept in place for the following morning, when the procedure is repeated exactly as before, except that subjects who received saline the first day are given nitrite the second day, and vice versa.
...
Read the detailed description
During exercise, there is a lag in the rate at which oxygen uptake (VO2) rises to meet energy demand. It is uncertain whether this limitation is due to inadequate O2 delivery to working muscle, limitations to the rate at which mitochondria can generate ATP to meet demand, or by a combination of both. Both of these limitations may be modulated by nitric oxide. Nitric oxide (NO) has been implicated in numerous physiological functions, including control of skeletal muscle vasodilation and oxidative metabolism. During exercise, NO will both vasodilate skeletal muscle and modulate (inhibit) mitochondrial respiration. The latter effect could either decrease oxygen extraction by limiting the ability of mitochondria to utilize oxygen, or paradoxically increase oxygen utilization by inhibiting mitochondria proximal to blood vessels, an effect that facilitates oxygen diffusion to distal tissue and mitochondria (NO dependent facilitated oxygen diffusion). Previous studies have demonstrated that NO production increases during exercise and regional inhibition of NO production from endothelial NO synthase reduces exercise-dependent blood flow by approximately 10%. NOS inhibitors such as N(G) -nitro-L-arginine methyl ester (L-NAME) have been shown to decrease exercise tolerance, and NO precursors (L-arginine) to increase exercise tolerance. Administration of inhaled NO during exercise has not been shown to increase exercise tolerance.
Considering the potential role of nitrite bioconversion to NO during hypoxia, is likely that nitrite plays an important role in modulating exercise physiology. We therefore hypothesize that during aerobic, and in particular anaerobic exercise, erythrocyte and plasma nitrite will be converted to NO and modulate muscle blood flow, mitochondrial respiration, oxygen diffusion and ultimately maximal oxygen consumption. While we expect these effects will increase maximal oxygen consumption and increase work output, it is also distinctly possible that NO production from nitrite during exercise will inhibit mitochondrial respiration and decrease maximal oxygen consumption. The purpose of the present study is to investigate the effects of aerobic-to-anaerobic exercise on circulating nitrite stores in erythrocytes and plasma in the arterial and central venous circulation and the effects of systemic nitrite infusion on aerobic and anaerobic exercise capacity. Physiological parameters including maximal oxygen consumption (VO2max), maximal CO2 and NO production (VCO2max and VNOmax), maximal work, rate of perceived exertion (RPE), anaerobic threshold, and pulmonary gas exchange (VO2, VCO2, VE) will be monitored during exercise with and without nitrite infusions. Our primary endpoint will be VO2 max with nitrite infusion compared to VO2 max with saline placebo infusion.
- Conditions
- Healthy, Healthy Volunteer, HV
- Being tested
- Sodium Nitrite
- Keywords
- Cycle Ergometer, Exercise Physiology, Nitric Oxide, Sodium Nitrite, Healthy Volunteers, Normal Volunteer, Healthy Volunteer, HV
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Sodium NitriteDrug
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted10 Mar 2005 (estimated)
- Study start8 Mar 2005
- Primary completion16 Aug 2013
- Study completion16 Aug 2013
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (3)Papers the sponsor has linked to this study.
- Other trials for HealthyStudies of the same condition, open and under way.
- More trials run by National Heart, Lung, and Blood Institute (NHLBI)The 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 1
- Primary purpose
- Treatment
- Enrolment
- 15 participants (actual)
Sponsor and investigators
- Sponsor type
- US National Institutes of Health
- Investigators
- Gregory J Kato, M.D., Principal investigator, National Heart, Lung, and Blood Institute (NHLBI)
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00105222
- Sponsor's protocol ID
- 050114
- Other IDs
- 05-H-0114
- Status last verified
- 16 Aug 2013
- First submitted
- 9 Mar 2005
- Last updated
- 5 Jul 2018
- Results posted
- No
Publications
Beckman JS, Koppenol WH. Nitric oxide, superoxide, and peroxynitrite: the good, the bad, and ugly. Am J Physiol. 1996 Nov;271(5 Pt 1):C1424-37. doi: 10.1152/ajpcell.1996.271.5.C1424.
PubMed 8944624Boucher JL, Moali C, Tenu JP. Nitric oxide biosynthesis, nitric oxide synthase inhibitors and arginase competition for L-arginine utilization. Cell Mol Life Sci. 1999 Jul;55(8-9):1015-28. doi: 10.1007/s000180050352.
PubMed 10484661Furchgott RF, Zawadzki JV. The obligatory role of endothelial cells in the relaxation of arterial smooth muscle by acetylcholine. Nature. 1980 Nov 27;288(5789):373-6. doi: 10.1038/288373a0.
PubMed 6253831
Study at a glance
From the registry record, last updated by the sponsor on 5 Jul 2018. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Evaluation of Systemic Nitrite Infusion and Its Effect on Exercise Physiology and Metabolism
- ClinicalTrials.gov ID
- NCT00105222
- Acronym / sponsor ID
- 050114
- Conditions
- Healthy, Healthy Volunteer, HV
- Keywords
- Cycle Ergometer, Exercise Physiology, Nitric Oxide, Sodium Nitrite, Healthy Volunteers, Normal Volunteer, Healthy Volunteer, HV
- Phase
- Phase 1
- Study type
- Interventional
- Recruitment status
- Terminated
- Enrolment
- 15 participants (actual)
- Lead sponsor
- National Heart, Lung, and Blood Institute (NHLBI)US National Institutes of Health
- Study start
- 8 Mar 2005
- Primary completion
- 16 Aug 2013 (actual)
- Study completion
- 16 Aug 2013 (actual)
- First posted
- 10 Mar 2005 (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.
This study will examine how nitrite infusions affect exercise tolerance (how much a person can exercise before having to stop). Exercise ability is limited by how fast oxygen can be delivered to the body and how fast the body can produce energy. Both of these processes are affected by nitric oxide (NO), a gas produced by cells that line blood vessels. NO is important in regulating blood vessel dilation, and consequently, blood flow. Nitrite may act as a storehouse for nitric oxide and be able to improve exercise tolerance.
Healthy normal volunteers between 21 and 45 years of age who can use an exercise bicycle may be eligible for this study. Candidates are screened with a medical history, physical examination, electrocardiogram, breathing tests, blood tests, and a pregnancy test for women who are able to bear children. Pregnant women are excluded from the study. The screening session includes practice exercise on the bicycle.
Participants exercise on a stationery exercise bicycle for about 30 minutes on each of two study days. During the test, they breathe in and out of a mouthpiece that allows inhaled and exhaled respiratory gases to be measured. Before subjects begin to exercise, a small tube is placed in the artery of their forearm inside the elbow. A longer tube called a central line is placed in a deeper vein in the neck after the area has been numbed. A thinner tube, called a pulmonary artery catheter, is placed through the central line and advanced into the chambers of the heart, through the heart valve, and into the lung artery. This catheter measures various pressures directly in the heart and lungs. Blood samples are drawn through the catheter also, to avoid the need for multiple needle sticks. Another tube is placed in the vein of the other arm to deliver medications.
Thirty minutes after all the tubes are placed, a blood sample is drawn for baseline measurements. Then, either saline (sterile salt water) or nitrite is injected into the tube in the arm vein. Thirty minutes after the injection, the subject starts exercising on the bicycle. The work setting on the bicycle is increased every minute, and the subject pedals until he or she is too tired to continue. During the test, a small blood sample is collected every 2 minutes. Heart rate, blood pressure, and heart rhythms are continuously monitored.
After the test on the first day, participants are admitted to the hospital to rest for the remainder of the afternoon and evening. The tubes are kept in place for the following morning, when the procedure is repeated exactly as before, except that subjects who received saline the first day are given nitrite the second day, and vice versa.
...
Detailed description
During exercise, there is a lag in the rate at which oxygen uptake (VO2) rises to meet energy demand. It is uncertain whether this limitation is due to inadequate O2 delivery to working muscle, limitations to the rate at which mitochondria can generate ATP to meet demand, or by a combination of both. Both of these limitations may be modulated by nitric oxide. Nitric oxide (NO) has been implicated in numerous physiological functions, including control of skeletal muscle vasodilation and oxidative metabolism. During exercise, NO will both vasodilate skeletal muscle and modulate (inhibit) mitochondrial respiration. The latter effect could either decrease oxygen extraction by limiting the ability of mitochondria to utilize oxygen, or paradoxically increase oxygen utilization by inhibiting mitochondria proximal to blood vessels, an effect that facilitates oxygen diffusion to distal tissue and mitochondria (NO dependent facilitated oxygen diffusion). Previous studies have demonstrated that NO production increases during exercise and regional inhibition of NO production from endothelial NO synthase reduces exercise-dependent blood flow by approximately 10%. NOS inhibitors such as N(G) -nitro-L-arginine methyl ester (L-NAME) have been shown to decrease exercise tolerance, and NO precursors (L-arginine) to increase exercise tolerance. Administration of inhaled NO during exercise has not been shown to increase exercise tolerance.
Considering the potential role of nitrite bioconversion to NO during hypoxia, is likely that nitrite plays an important role in modulating exercise physiology. We therefore hypothesize that during aerobic, and in particular anaerobic exercise, erythrocyte and plasma nitrite will be converted to NO and modulate muscle blood flow, mitochondrial respiration, oxygen diffusion and ultimately maximal oxygen consumption. While we expect these effects will increase maximal oxygen consumption and increase work output, it is also distinctly possible that NO production from nitrite during exercise will inhibit mitochondrial respiration and decrease maximal oxygen consumption. The purpose of the present study is to investigate the effects of aerobic-to-anaerobic exercise on circulating nitrite stores in erythrocytes and plasma in the arterial and central venous circulation and the effects of systemic nitrite infusion on aerobic and anaerobic exercise capacity. Physiological parameters including maximal oxygen consumption (VO2max), maximal CO2 and NO production (VCO2max and VNOmax), maximal work, rate of perceived exertion (RPE), anaerobic threshold, and pulmonary gas exchange (VO2, VCO2, VE) will be monitored during exercise with and without nitrite infusions. Our primary endpoint will be VO2 max with nitrite infusion compared to VO2 max with saline placebo infusion.
Study design
- Primary purpose
- Treatment
Who may qualify
- Ages
- 21 to 45 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- Subjects must be 21-45 years of age.
- Subject must be in good health and able to perform cycle ergometry for the length of the study.
- Subjects must provide informed, written consent for participation in this study.
- Female subjects of childbearing age must have a negative pregnancy test.
Key exclusion criteria (12 listed)
- Subjects with a history of cardiac, pulmonary, peripheral vascular, or mitochondrial disease.
- Subjects with abnormal EKG other than sinus bradycardia.
- Individuals with a future cardiovascular risk greater than 1 % in the next 10 years will be excluded from the study. Risk will be calculated using the Framingham risk calculator published on the web site: http://hin.nhlbi.nih.gov/atpiii/calculator.asp?usertype=prof.
- Subjects with any physical condition (for example, knee problems) that may impair their performance during exercise testing.
- Subjects who have a history of smoking within one year.
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 |
|---|---|---|
| Sodium Nitrite | Drug | – |
Primary outcome
Not reported in the source record.
Results and safety
The study was stopped early. Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 5 Jul 2018.
- Background: PubMed 8944624Beckman JS, Koppenol WH. Nitric oxide, superoxide, and peroxynitrite: the good, the bad, and ugly. Am J Physiol. 1996 Nov;271(5 Pt 1):C1424-37. doi: 10.1152/ajpcell.1996.271.5.C1424.
- Background: PubMed 10484661Boucher JL, Moali C, Tenu JP. Nitric oxide biosynthesis, nitric oxide synthase inhibitors and arginase competition for L-arginine utilization. Cell Mol Life Sci. 1999 Jul;55(8-9):1015-28. doi: 10.1007/s000180050352.
- Background: PubMed 6253831Furchgott RF, Zawadzki JV. The obligatory role of endothelial cells in the relaxation of arterial smooth muscle by acetylcholine. Nature. 1980 Nov 27;288(5789):373-6. doi: 10.1038/288373a0.
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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.
Gregory J Kato, M.D. principal investigator
National Heart, Lung, and Blood Institute (NHLBI)
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1 study testing Sodium Nitrite in people with Healthy and Healthy Volunteer, run by National Heart, Lung, and Blood Institute (NHLBI) at 1 site in United States.
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 4 inclusion and 12 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: stopped early, as of the sponsor's last update on 5 Jul 2018. 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 United States. 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 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
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 stopped early. Results are not available in the source record.
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.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT00105222, which also lists 3 linked publications.
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 5 Jul 2018.