Diesel Exhaust and Vascular Function

NCT01508637 — Not applicable, Unknown, 24 participants, University of Washington

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Effect of Diesel Exhaust Exposures on Vascular Function in Humans: The Role of Sympathetic Activation

Registry	NCT01508637, acronym CVDTRAP4
Status	Unknown
Phase	Not applicable
Study type	Interventional; randomized, crossover, masking: triple, prevention
Enrollment	24 (Estimated)
Sponsor	University of Washington (Other); collaborators: National Institute of Environmental Health Sciences (NIEHS), Environmental Protection Agency (EPA)
Conditions	Cardiovascular Effects
Interventions	Diesel Exhaust, Filtered Air, Terazosin, placebo (Other, drug)
Dates	start 2012-01-01, primary completion 2015-12-01 (estimated), completion 2015-12-01 (estimated), first posted 2012-01-12, last updated 2015-08-03
Locations	1 site in United States

-Summary

Double-blind, sham- and placebo-controlled randomized study of effects of freshly-generated diluted diesel exhaust inhalation on vascular function. To examine role of adrenergic system a trial of alpha-blocker terazosin is also used. Each participant completes four study sessions, separated by at least three weeks: 1) Diesel exhaust inhalation (DE, controlled at 300 micrograms/cubic meter for two hours) and terazosin (2 mg prior to inhalation exposure); 2) DE plus placebo (matched for terazosin); 3) filtered air plus terazosin; and 4) filter air plus placebo. The investigators assess outcomes of blood pressure, forearm brachial artery ultrasound, and plasma measures of endothelial activation. The investigators hypothesize that DE exposure will be associated with increased blood pressure, decreased brachial artery diameter, and increased circulating endothelins, and that these effects will be attenuated by terazosin administration.

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+Arms and interventions

Arm	Type	Interventions
Diesel Exhaust + Terazosin	Experimental	Other: Diesel Exhaust; Drug: Terazosin
Diesel Exhaust + placebo	Experimental	Other: Diesel Exhaust; Drug: placebo
Filtered Air + terazosin	Sham comparator	Other: Filtered Air; Drug: Terazosin
Filtered air + placebo	Sham comparator	Other: Filtered Air; Drug: placebo

Diesel Exhaust (Other): Freshly generated diesel exhaust, diluted to 300 micrograms/cubic meter. Exposures are two hours in duration.
Filtered Air (Other): Sham exposure, identical to conditions of diesel exhaust exposure, but with only air filtered of particles and volatile organic compound gases
Terazosin (Drug): 2 mg by mouth, 90 minutes prior to exposure initiation
placebo (Drug): capsule, identical in appearance to terazosin capsule, by mouth, 30 minutes prior to exposure initiation

+Outcome measures

Primary outcomes

Systolic Blood Pressure [30-90 minutes after exposure initiation]

Secondary outcomes

Brachial artery diameter [Assessed 30 minutes prior to exposure and 30 minutes post-exposure]: The investigators anticipate vasoconstriction (post-exposure vs. pre-exposure) as observed in this conduit artery in response to exposure to Diesel Exhaust, compared to Filtered Air sham exposure.

+Eligibility

Sex: All, ages: 18 Years to 49 Years, accepts healthy volunteers

Inclusion Criteria:

* healthy without chronic illness
* Body Mass Index 18.5 - 26.0
* tolerates 2 mg terazosin dose without unacceptable symptoms
* able to return for four exposure sessions

Exclusion Criteria:

* any chronic disease
* tobacco user
* asthma
* elevated cholesterol
* obesity
* hypertension
* diabetes
* any chronic cardiovascular or pulmonary disease
* pregnancy or unwillingness to use effective contraception, if female

+Locations (1)

Facility	City	Country	Status
University of Washington Medical Center	Seattle, Washington	United States	Recruiting

+Investigators

Joel D Kaufman, MD, MPH, Principal investigator, University of Washington

+Funding

NIH grants: P50ES015915

My Notes

Public

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