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Completed

NCT Number: NCT01060930

Diesel Exhaust Inhalation, Systemic Nitric Oxide Inhibition and Cardiac Output

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.

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Key information

Conditions

Vascular Function in Healthy Volunteers

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University Hospital Umeå

Umeå, Sweden

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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)

Treatment and study plan

Intravenous infusion of L-NMMA and Nor-epinephrine

Drug

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

Primary outcomes

  1. Blood pressure response to NO inhibition

    Time frame: Blood pressure will be measured continuously through the vascular study using intra-arterial monitoring

Secondary outcomes

  1. Heart rate response to systemic nitric oxide inhibition

    Time frame: Heart rate will be measured continuously throughout the study period using continous electrocardiography

  2. Central arterial stiffness following NO inhibition

    Time frame: Measured at baseline, and every 5 minutes during the 2-hour vascular study

  3. Cardiac output during NO inhibition

    Time frame: Measured at baseline, and every 5 minutes during the 2-hour vascular study

  4. Plasma nitrite (NO) concentrations

    Time frame: Measured at baseline, and every 15 minutes during the 2-hour vascular study

  5. Platelet activation and platelet-monocyte binding

    Time frame: Measured at baseline, and every 30 minutes during the 2-hour vascular study

  6. 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

Sponsors and collaborators

Lead sponsor

University of Edinburgh

Other

Collaborators

  • NHS Lothian
  • Umeå University

Registry information

Acronym: DISCO

Important dates

Study start
2010
Primary completion
2010
Study completion
2010
First posted
Feb 2, 2010
Registry last updated
Dec 16, 2011

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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