Diesel Exhaust and Vascular Function

Not Applicable

• Conditions: Cardiovascular Effects
• Interventions: Other: Filtered Air; Other: Diesel Exhaust; Drug: Terazosin; Drug: placebo

• Registration Number: NCT01508637
• Lead Sponsor: University of Washington

Brief 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.

Detailed Description

Not available

Study Timeline

• Study Start: 2012-01
• Study First Submitted: 2012-01-05
• Study First Submitted QC: 2012-01-11
• Study First Posted: 2012-01-12
• Status Verified: 2015-07
• Last Update Submitted: 2015-07-30
• Last Update Posted: 2015-08-03
• Primary Completion: 2015-12
• Study Completion: 2015-12

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: All
• Target Recruitment: 24

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

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Filtered Air + terazosin	Terazosin	-
Filtered air + placebo	Filtered Air	-
Filtered air + placebo	placebo	-
Diesel Exhaust + Terazosin	Diesel Exhaust	-
Diesel Exhaust + Terazosin	Terazosin	-
Diesel Exhaust + placebo	Diesel Exhaust	-
Diesel Exhaust + placebo	placebo	-
Filtered Air + terazosin	Filtered Air	-

Primary Outcome Measures

Name	Time	Method
Systolic Blood Pressure	30-90 minutes after exposure initiation

Secondary Outcome Measures

Name	Time	Method
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.

Trial Locations

Locations (1)

University of Washington Medical Center; 🇺🇸 Seattle, Washington, United States