Diesel Exhaust and Vascular Function

University of Washington24 enrolled

Overview

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.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

TRIPLE

Enrollment

Conditions

Cardiovascular Effects

Interventions

Freshly generated diesel exhaust, diluted to 300 micrograms/cubic meter. Exposures are two hours in duration.

Filtered AirOTHER

Sham exposure, identical to conditions of diesel exhaust exposure, but with only air filtered of particles and volatile organic compound gases

TerazosinDRUG

2 mg by mouth, 90 minutes prior to exposure initiation

placeboDRUG

capsule, identical in appearance to terazosin capsule, by mouth, 30 minutes prior to exposure initiation

Eligibility

Sex: ALLMin age: 18 YearsMax age: 49 YearsHealthy volunteers:

Medical Language ↔ Plain English

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)

University of Washington Medical Center

Seattle, Washington, United States

RECRUITING

Outcomes

Primary Outcomes

Systolic Blood Pressure

Time frame: 30-90 minutes after exposure initiation

Secondary Outcomes

Brachial artery diameter

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.

Time frame: Assessed 30 minutes prior to exposure and 30 minutes post-exposure

Central Contacts

Karen Jansen, M.S.

CONTACT

206-616-6525 cvd1trap@uw.edu

Data from ClinicalTrials.gov

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