Blood PressureNCT03433963
The Use of L-arginine to Mitigate the Cardiovascular Effects of Exposure to Traffic-related Air Pollution
A study testing L-Arg supplement in people with Blood Pressure and Cardiac Ischemia, run by Peking University at 3 sites in China.
Trial summary
The present study is aimed to investigate whether oral L-arginine supplementation reduces the adverse cardiovascular effects of exposure to traffic-related air pollution among a group of non-smoking adults with elevated blood pressure. Read more about this study
- Who is it for?
- Ages 50 to 75 yearsHealthy volunteers can take part
- Conditions the study is for
- Blood Pressure, Cardiac Ischemia
- What is being tested?
- L-Arg supplement
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 118 participants
- Where
- 3 sitesChina
- Study dates
- 2 Jan 2018to 31 Mar 2020
- 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 50 to 75 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Having elevated systolic blood pressure between 120-160 mmHg, and diastolic blood pressure between 65-100 mmHg, either with or without routine antihypertensive medications.
- Adults between 50 and 75 years of age, current non-smokers;
- Do not take routine vasoactive dietary supplements.
Who cannot join
- Hypertension with SBP>160 mmHg or DBP>100 mmHg, clinical diagnosis of cardiovascular disease (excluding hypertension), or other important chronic diseases such as coagulopathy, chronic obstructive pulmonary disease, asthma, gastrointestinal diseases, cancer or mental diseases;
- No routine use of vasoactive dietary supplements,or, if taking, willing to forego their use during the trial.
- Fasting LDL cholesterol≥4.92 mmol/L or total cholesterol≥6.21 mmol/L or HbA1c>9%;
- Liver or renal dysfunction;
- Acute coronary symptoms or unstable clinical manifestations within the past three months;
- Suffering from allergic diseases/known allergy to ingredients of L-Arg; or those who suffered from acute illness before start of the study;
Show all 11Show fewer
- Alcohol or drug addiction;
- Hepatitis B / hepatitis C virus patient / carrier;
- History of organ transplants or major surgery in the past year;
- Exposed to occupational sources of air pollution;
- Unwilling or unable to provide informed consent or cooperate with all research related procedures.
Trial locations and contacts
3 sites in 1 country.
China3 sites
Qinglongqiao Community Health Service Center
Beijing, 100091
Malianwa Community Health Service Center
Beijing, 100191
Shangdi Community Health Service Center
Beijing, 100191
About this study
Official title: The Use of L-arginine to Mitigate the Cardiovascular Effects of Exposure to Traffic-related Air Pollution: A Randomized, Double-blind, Placebo-controlled Trial
The present study is aimed to investigate whether oral L-arginine supplementation reduces the adverse cardiovascular effects of exposure to traffic-related air pollution among a group of non-smoking adults with elevated blood pressure.
Read the detailed description
The present study is designed as a randomized, double-blind, placebo-controlled trial of L-arginine (L-Arg, a precursor of nitric oxide in human body) supplement to counteract the acute cardiovascular effects of exposure to traffic-related air pollution among a group of non-smoking adults with elevated blood pressure. A large number of epidemiological studies have provided compelling evidence that exposure to traffic-related air pollution contributes to the increases in cardiovascular morbidity and mortality, and the mechanism of action includes vasoconstriction and cardiac ischemia. It is well known that nutritional factors are very important determinants of cardiovascular health. However, few studies have explored the joint effects of air pollution and nutritional factors on cardiovascular health. Existing data from many laboratory studies and small clinical trials suggest that L-Arg has beneficial effects on the cardiovascular system by lowering blood pressure and protecting myocardiocytes against external stimuli. The study will explore whether L-Arg supplement improves blood pressure levels and prevents potential cardiac ischemia upon acute exposure to traffic-related air pollution among high-risk individuals.
Dietary intakes, lifestyle habits, use of medication/dietary supplements, blood pressure, resting electrocardiogram and plasma parameters were assessed for potential eligible participants at screening visits. Over 500 participants completed the screening visits, and 118 of them were eligible after a 5-day L-Arg-free run-in period and willing to participate in the following intervention. Eligible participants were assigned to either the interventional group or control group using a computerized method with a randomized block design. They received 2 weeks (may float back and forth for 1-3 days due to scheduling issues) daily doses of either L-Arg (9g/day in 3 times) or placebo and undergo a 2-h exposure scenario (0900-1100 hours) of walking along a traffic road on the 14th day. Participants were counseled to maintain an isocaloric diet and to abstain from other L-Arg rich foods during the study. Concentrations of major traffic-related air pollutants, including particulate matter with an aerodynamic diameter ≤ 2.5 μm (PM2.5), black carbon, and nitrogen dioxide, were measured from the beginning of the 2-h exposure scenario to 22h after exposure or during the 2-h exposure scenario, and primary and secondary outcome measures including blood pressure, ST-segment depression and plasma parameters were assessed repeatedly at various time points (depending on the parameters) around the 2-h exposure scenario. Other environmental factors, including noise, temperature and relative humidity, were also recorded during the 2-h exposure scenario and up to 22h after exposure.
- Conditions
- Blood Pressure, Cardiac Ischemia
- Being tested
- L-Arg supplement, Placebo
- Keywords
- air pollution, blood pressure, cardiac ischemia, L-arginine, nitric oxide
- Medical subject headings
- Coronary Artery Disease
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
L-Arg supplementDietary supplement
L-Arg supplement will be prepared as pills, administered 9g each day in 3 times for 2 weeks.
PlaceboDietary supplement
Placebo will be prepared as pills (the same size, color and shape as of L-Arg), administered 3 times daily for 2 weeks.
| Study group | Role | What they receive |
|---|---|---|
| L-Arg supplement group | Experimental | Study participants in the group will take L-Arg supplement during the trial. Receives: Dietary Supplement: L-Arg supplement |
| Control group | Placebo comparator | Study participants in the group will take placebo during the trial. Receives: Dietary Supplement: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in systolic and diastolic blood pressure from before the dietary intervention to before, during, 30min after and 22h after the 2-h exposure scenario
Measured: before taking L-Arg supplement/placebo (1st day); before and during the 2-h exposure scenario (14th day); 30min after the exposure scenario (14th day); and 22h after the exposure scenario (15th day).
Change in ST-segment depression from before the dietary intervention to before, during until 22h after the 2-h exposure scenario
Measured: before taking L-Arg supplement/placebo (1st day); and 24 hours from the start of 2-h exposure scenario (14th day) until 22h after the exposure scenario (15th day)
Change in ambulatory blood pressure during the 2-h exposure scenario (vs. before the dietary intervention)
Measured: during the 2-h exposure scenario (14th day)
Secondary outcomes (8)
Change in plasma L-Arg from before the dietary intervention to before, 30min after and 22h after the 2-h exposure scenario
Measured: before taking L-Arg supplement/placebo (1st day); before the 2-h exposure scenario (14th day); 30min after the exposure scenario (14th day); and 22 hours after the exposure scenario (15th day)
Change in plasma nitric oxide (including nitrate and nitrite) from before the dietary intervention to before, 30min after and 22h after the 2-h exposure scenario
Measured: before taking L-Arg supplement/placebo (1st day); before the 2-h exposure scenario (14th day); 30min after the exposure scenario (14th day); and 22 hours after the exposure scenario (15th day)
Change in plasma cyclic guanosine monophosphate from before the dietary intervention to before, 30min after and 22h after the 2-h exposure scenario
Measured: before taking L-Arg supplement/placebo (1st day); before the 2-h exposure scenario (14th day); 30min after the exposure scenario (14th day); and 22 hours after the exposure scenario (15th day)
Change in plasma C-reactive protein from before the dietary intervention to before, 30min after and 22h after the 2-h exposure scenario
Measured: before taking L-Arg supplement/placebo (1st day); before the 2-h exposure scenario (14th day); 30min after the exposure scenario (14th day); and 22 hours after the exposure scenario (15th day)
Change in plasma myeloperoxidase from before the dietary intervention to before, 30min after and 22h after the 2-h exposure scenario
Measured: before taking L-Arg supplement/placebo (1st day); before the 2-h exposure scenario (14th day); 30min after the exposure scenario (14th day); and 22 hours after the exposure scenario (15th day)
Change in pulse oxygen saturation from before the dietary intervention to before, 30min after and 22h after the 2-h exposure scenario
Measured: before taking L-Arg supplement/placebo (1st day); before the 2-h exposure scenario (14th day); 30min after the exposure scenario (14th day); and 22 hours after the exposure scenario (15th day)
Change in endothelial nitric oxide synthase from before the dietary intervention to before, 30min after and 22h after the 2-h exposure scenario
Measured: before taking L-Arg supplement/placebo (1st day); before the 2-h exposure scenario (14th day); 30min after the exposure scenario (14th day); and 22 hours after the exposure scenario (15th day)
Change in two related amino acids (citrulline and ornithine) in L-arg metabolic pathway from before the dietary intervention to before, 30min after and 22h after the 2-h exposure scenario
Measured: before taking L-Arg supplement/placebo (1st day); before the 2-h exposure scenario (14th day); 30min after the exposure scenario (14th day); and 22 hours after the exposure scenario (15th day)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Feb 2018
- Study start2 Jan 2018
- Primary completion4 Jul 2019
- Study completion31 Mar 2020
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Blood PressureStudies of the same condition, open and under way.
- More trials run by Peking UniversityThe 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
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 118 participants (actual)
Sponsor and investigators
- Lead sponsor
- Peking University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Shaowei Wu, Peking University
- Investigators
- Shaowei Wu, PhD, Principal investigator, Peking University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03433963
- Sponsor's protocol ID
- 2017074
- Status last verified
- Mar 2021
- First submitted
- 31 Jan 2018
- Last updated
- 10 Mar 2021
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 10 Mar 2021. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Use of L-arginine to Mitigate the Cardiovascular Effects of Exposure to Traffic-related Air Pollution: A Randomized, Double-blind, Placebo-controlled Trial
- ClinicalTrials.gov ID
- NCT03433963
- Acronym / sponsor ID
- 2017074
- Conditions
- Blood Pressure, Cardiac Ischemia
- Keywords
- air pollution, blood pressure, cardiac ischemia, L-arginine, nitric oxide
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 118 participants (actual)
- Lead sponsor
- Peking UniversityUniversity, hospital or other
- Study start
- 2 Jan 2018 (actual)
- Primary completion
- 4 Jul 2019 (actual)
- Study completion
- 31 Mar 2020 (actual)
- First posted
- 15 Feb 2018 (actual)
- 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.
The present study is aimed to investigate whether oral L-arginine supplementation reduces the adverse cardiovascular effects of exposure to traffic-related air pollution among a group of non-smoking adults with elevated blood pressure.
Detailed description
The present study is designed as a randomized, double-blind, placebo-controlled trial of L-arginine (L-Arg, a precursor of nitric oxide in human body) supplement to counteract the acute cardiovascular effects of exposure to traffic-related air pollution among a group of non-smoking adults with elevated blood pressure. A large number of epidemiological studies have provided compelling evidence that exposure to traffic-related air pollution contributes to the increases in cardiovascular morbidity and mortality, and the mechanism of action includes vasoconstriction and cardiac ischemia. It is well known that nutritional factors are very important determinants of cardiovascular health. However, few studies have explored the joint effects of air pollution and nutritional factors on cardiovascular health. Existing data from many laboratory studies and small clinical trials suggest that L-Arg has beneficial effects on the cardiovascular system by lowering blood pressure and protecting myocardiocytes against external stimuli. The study will explore whether L-Arg supplement improves blood pressure levels and prevents potential cardiac ischemia upon acute exposure to traffic-related air pollution among high-risk individuals.
Dietary intakes, lifestyle habits, use of medication/dietary supplements, blood pressure, resting electrocardiogram and plasma parameters were assessed for potential eligible participants at screening visits. Over 500 participants completed the screening visits, and 118 of them were eligible after a 5-day L-Arg-free run-in period and willing to participate in the following intervention. Eligible participants were assigned to either the interventional group or control group using a computerized method with a randomized block design. They received 2 weeks (may float back and forth for 1-3 days due to scheduling issues) daily doses of either L-Arg (9g/day in 3 times) or placebo and undergo a 2-h exposure scenario (0900-1100 hours) of walking along a traffic road on the 14th day. Participants were counseled to maintain an isocaloric diet and to abstain from other L-Arg rich foods during the study. Concentrations of major traffic-related air pollutants, including particulate matter with an aerodynamic diameter ≤ 2.5 μm (PM2.5), black carbon, and nitrogen dioxide, were measured from the beginning of the 2-h exposure scenario to 22h after exposure or during the 2-h exposure scenario, and primary and secondary outcome measures including blood pressure, ST-segment depression and plasma parameters were assessed repeatedly at various time points (depending on the parameters) around the 2-h exposure scenario. Other environmental factors, including noise, temperature and relative humidity, were also recorded during the 2-h exposure scenario and up to 22h after exposure.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| L-Arg supplement group | Experimental | Dietary Supplement: L-Arg supplementStudy participants in the group will take L-Arg supplement during the trial. |
| Control group | Placebo comparator | Dietary Supplement: PlaceboStudy participants in the group will take placebo during the trial. |
Who may qualify
- Ages
- 50 to 75 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Having elevated systolic blood pressure between 120-160 mmHg, and diastolic blood pressure between 65-100 mmHg, either with or without routine antihypertensive medications.
- Adults between 50 and 75 years of age, current non-smokers;
- Do not take routine vasoactive dietary supplements.
Key exclusion criteria (11 listed)
- Hypertension with SBP>160 mmHg or DBP>100 mmHg, clinical diagnosis of cardiovascular disease (excluding hypertension), or other important chronic diseases such as coagulopathy, chronic obstructive pulmonary disease, asthma, gastrointestinal diseases, cancer or mental diseases;
- No routine use of vasoactive dietary supplements,or, if taking, willing to forego their use during the trial.
- Fasting LDL cholesterol≥4.92 mmol/L or total cholesterol≥6.21 mmol/L or HbA1c>9%;
- Liver or renal dysfunction;
- Acute coronary symptoms or unstable clinical manifestations within the past three months;
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 |
|---|---|---|
| L-Arg supplementL-Arg supplement will be prepared as pills, administered 9g each day in 3 times for 2 weeks. | Dietary supplement | L-Arg supplement group |
| PlaceboPlacebo will be prepared as pills (the same size, color and shape as of L-Arg), administered 3 times daily for 2 weeks. | Dietary supplement | Control group |
Primary outcome
Change in systolic and diastolic blood pressure from before the dietary intervention to before, during, 30min after and 22h after the 2-h exposure scenario
Time frame: before taking L-Arg supplement/placebo (1st day); before and during the 2-h exposure scenario (14th day); 30min after the exposure scenario (14th day); and 22h after the exposure scenario (15th day).
Change in ST-segment depression from before the dietary intervention to before, during until 22h after the 2-h exposure scenario
Time frame: before taking L-Arg supplement/placebo (1st day); and 24 hours from the start of 2-h exposure scenario (14th day) until 22h after the exposure scenario (15th day)
Change in ambulatory blood pressure during the 2-h exposure scenario (vs. before the dietary intervention)
Time frame: during the 2-h exposure scenario (14th day)
8 secondary outcomes
Change in plasma L-Arg from before the dietary intervention to before, 30min after and 22h after the 2-h exposure scenario
Time frame: before taking L-Arg supplement/placebo (1st day); before the 2-h exposure scenario (14th day); 30min after the exposure scenario (14th day); and 22 hours after the exposure scenario (15th day)
Change in plasma nitric oxide (including nitrate and nitrite) from before the dietary intervention to before, 30min after and 22h after the 2-h exposure scenario
Time frame: before taking L-Arg supplement/placebo (1st day); before the 2-h exposure scenario (14th day); 30min after the exposure scenario (14th day); and 22 hours after the exposure scenario (15th day)
Change in plasma cyclic guanosine monophosphate from before the dietary intervention to before, 30min after and 22h after the 2-h exposure scenario
Time frame: before taking L-Arg supplement/placebo (1st day); before the 2-h exposure scenario (14th day); 30min after the exposure scenario (14th day); and 22 hours after the exposure scenario (15th day)
Change in plasma C-reactive protein from before the dietary intervention to before, 30min after and 22h after the 2-h exposure scenario
Time frame: before taking L-Arg supplement/placebo (1st day); before the 2-h exposure scenario (14th day); 30min after the exposure scenario (14th day); and 22 hours after the exposure scenario (15th day)
Change in plasma myeloperoxidase from before the dietary intervention to before, 30min after and 22h after the 2-h exposure scenario
Time frame: before taking L-Arg supplement/placebo (1st day); before the 2-h exposure scenario (14th day); 30min after the exposure scenario (14th day); and 22 hours after the exposure scenario (15th day)
Change in pulse oxygen saturation from before the dietary intervention to before, 30min after and 22h after the 2-h exposure scenario
Time frame: before taking L-Arg supplement/placebo (1st day); before the 2-h exposure scenario (14th day); 30min after the exposure scenario (14th day); and 22 hours after the exposure scenario (15th day)
Change in endothelial nitric oxide synthase from before the dietary intervention to before, 30min after and 22h after the 2-h exposure scenario
Time frame: before taking L-Arg supplement/placebo (1st day); before the 2-h exposure scenario (14th day); 30min after the exposure scenario (14th day); and 22 hours after the exposure scenario (15th day)
Change in two related amino acids (citrulline and ornithine) in L-arg metabolic pathway from before the dietary intervention to before, 30min after and 22h after the 2-h exposure scenario
Time frame: before taking L-Arg supplement/placebo (1st day); before the 2-h exposure scenario (14th day); 30min after the exposure scenario (14th day); and 22 hours after the exposure scenario (15th day)
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 10 Mar 2021.
- Individual participant dataSharing planned: No
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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.
Shaowei Wu, PhD principal investigator
Peking University
3 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing L-Arg supplement in people with Blood Pressure and Cardiac Ischemia, run by Peking University at 3 sites in China.
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 3 inclusion and 11 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 10 Mar 2021. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 3 sites in China. 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?
Change in systolic and diastolic blood pressure from before the dietary intervention to before, during, 30min after and 22h after the 2-h exposure scenario (time frame: before taking L-Arg supplement/placebo (1st day); before and during the 2-h exposure scenario (14th day); 30min after the exposure scenario (14th day); and 22h after the exposure scenario (15th day).). The study lists 3 primary outcomes in all. 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 10 Mar 2021.