Diesel Exhaust Inhalation, Systemic Nitric Oxide Inhibition and Cardiac Output (DISCO)

December 15, 2011 updated by: University of Edinburgh
Exposure to combustion-derived fine particulate air pollution is associated with cardiovascular mortality and morbidity. In previous studies, exposure to diesel exhaust (a major constituent of urban particulate air pollution) has been shown to impair two important functions of the vascular endothelium: vascular vasomotor function and endogenous fibrinolysis. Our subsequent studies suggest this impairment of vascular function is mediated by a reduction in nitric oxide bioavailability. In this study we aim to investigate the cardiovascular responses to systemic nitric oxide synthase inhibition following exposure to dilute diesel exhaust.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

14

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Sweden
      • Umeå, Sweden
        • University Hospital Umeå

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Healthy volunteers
  • Non smokers
  • No regular medication (except oral contraceptive)
  • No recent respiratory tract infection (within 6 weeks)

Exclusion Criteria:

  • History of asthma or respiratory disease
  • Smoking history
  • Pregnancy (positive urinary pregnancy test)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Diesel exhaust exposure
1 hour exposure to dilute diesel exhaust ~ 300 mcg/m3 - during intermittent exercise
Drug: Intravenous infusion of L-NMMA and Nor-epinephrine
Intravenous infusion of 3mg/kg L-NMMA (L-NG-monomethyl arginine; NO synthase inhibitor) and nor-epinephrine at 50 ng/kg/min. Each infusion to run over 15 mins and separated by 45 min to allow return to baseline. Drugs infused in a randomised order. During the study, blood pressure will be measured invasively using an intra-arterial radial artery cannula, central arterial stiffness measured using peripheral arterial tonometry and cardiac output using thoracic bioimpedance.
Other Names:
  • L-NMMA: Clinalfa Basic, Bachem, Germany
Experimental: Air exposure
1 hour exposure to filtered air during intermittent exercise
Drug: Intravenous infusion of L-NMMA and Nor-epinephrine
Intravenous infusion of 3mg/kg L-NMMA (L-NG-monomethyl arginine; NO synthase inhibitor) and nor-epinephrine at 50 ng/kg/min. Each infusion to run over 15 mins and separated by 45 min to allow return to baseline. Drugs infused in a randomised order. During the study, blood pressure will be measured invasively using an intra-arterial radial artery cannula, central arterial stiffness measured using peripheral arterial tonometry and cardiac output using thoracic bioimpedance.
Other Names:
  • L-NMMA: Clinalfa Basic, Bachem, Germany

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Blood pressure response to NO inhibition
Time Frame: Blood pressure will be measured continuously through the vascular study using intra-arterial monitoring
Blood pressure will be measured continuously through the vascular study using intra-arterial monitoring

Secondary Outcome Measures

Outcome Measure
Time Frame
Heart rate response to systemic nitric oxide inhibition
Time Frame: Heart rate will be measured continuously throughout the study period using continous electrocardiography
Heart rate will be measured continuously throughout the study period using continous electrocardiography
Central arterial stiffness following NO inhibition
Time Frame: Measured at baseline, and every 5 minutes during the 2-hour vascular study
Measured at baseline, and every 5 minutes during the 2-hour vascular study
Cardiac output during NO inhibition
Time Frame: Measured at baseline, and every 5 minutes during the 2-hour vascular study
Measured at baseline, and every 5 minutes during the 2-hour vascular study
Plasma nitrite (NO) concentrations
Time Frame: Measured at baseline, and every 15 minutes during the 2-hour vascular study
Measured at baseline, and every 15 minutes during the 2-hour vascular study
Platelet activation and platelet-monocyte binding
Time Frame: Measured at baseline, and every 30 minutes during the 2-hour vascular study
Measured at baseline, and every 30 minutes during the 2-hour vascular study
Heart rate variability
Time Frame: Heart rate will be measured continuously throughout the study period using continous electrocardiography, and HRV subsequently determined for the whole study period and the 2-hour vascular study separately
Heart rate will be measured continuously throughout the study period using continous electrocardiography, and HRV subsequently determined for the whole study period and the 2-hour vascular study separately

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Edinburgh

Collaborators

Umeå University
NHS Lothian

Investigators

  • Principal Investigator: Jeremy P Langrish, MB BCh MRCP, University of Edinburgh

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

March 1, 2010

Primary Completion (Actual)

June 1, 2010

Study Completion (Actual)

June 1, 2010

Study Registration Dates

First Submitted

January 28, 2010

First Submitted That Met QC Criteria

February 1, 2010

First Posted (Estimate)

February 2, 2010

Study Record Updates

Last Update Posted (Estimate)

December 16, 2011

Last Update Submitted That Met QC Criteria

December 15, 2011

Last Verified

April 1, 2011

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • DISCO

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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