Diesel Exhaust and Vascular Function

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

Status

UNKNOWN

Phases

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT01508637

Acronym

CVDTRAP4

Enrollment

Registered

2012-01-12

Start date

2012-01-31

Completion date

2015-12-31

Last updated

2015-08-03

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Cardiovascular Effects

Keywords

air pollution, vasoconstriction, blood pressure, diesel exhaust

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.

Interventions

OTHERDiesel Exhaust

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

OTHERFiltered Air

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

DRUGTerazosin

2 mg by mouth, 90 minutes prior to exposure initiation

DRUGplacebo

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

Study design

Allocation

RANDOMIZED

Intervention model

CROSSOVER

Primary purpose

PREVENTION

Masking

TRIPLE (Subject, Investigator, Outcomes Assessor)

Eligibility

Sex/Gender

ALL

Age

18 Years to 49 Years

Healthy volunteers

Yes

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

Design outcomes

Primary

Measure	Time frame
Systolic Blood Pressure	30-90 minutes after exposure initiation

Secondary

Measure	Time frame	Description
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.

Countries

United States

Contacts

Primary ContactKaren Jansen, M.S.

cvd1trap@uw.edu206-616-6525

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026