The Effects of Diesel Exhaust Inhalation on Vascular Function - the Role of Endothelin

What Was Tested

In this not phased trial, researchers set out to test Endothelin-1.

It had four arms (groups): 1 (experimental), 2 (experimental), 3 (experimental) and 4 (experimental).

1 hour exposure to filtered air, followed by forearm venous occlusion plethysmography at 2 hours after the exposure and infusion of endothelin receptor antagonists BQ-123 and BQ-788.

The registry classes the interventions as drug.

More on the Plan

There are strong associations between air pollution exposure and heart disease but the researchers do not yet understand how these harmful effects are mediated.

The upregulation of Endothelin-1 provides a plausible mechanism for these harmful effects, and the researchers plan to investigate this in more depth in the human forearm following exposure to diesel exhaust.

Who Took Part

The registry lists 15 actual participants took part.

It was open to men only aged from 18 years up to 35 years.

Healthy volunteers could join, not only people with the condition.

Examples of who could join: Healthy male volunteers.

The full record lists 1 inclusion and 4 exclusion criteria; among the exclusions: use of regular medication; cigarette smoking; intercurrent illness.

How the Study Was Run

Design: randomized, crossover and triple-blind.

Because people in this Endothelin-1 study were split into groups at random, differences between the groups are less likely to reflect who happened to join each one.

Each person switched between Endothelin-1 and the comparison at some point, usually with a gap in between.

Blinding on both sides kept the participants and researchers unaware of who received Endothelin-1.

Those kept unaware of assignments: participant, investigator and outcomes assessor.

It started in 2008-03 with completion listed for 2008-05.

It ran at 1 site in Sweden.

Its stated primary purpose is basic science.

What Was Measured

Primary outcome: Change in forearm blood flow following infusion of endothelin-1 or the endothelin receptor antagonists BQ-123 & BQ-788 (time frame: 2 hours after exposure).

It also tracked 3 secondary outcomes, for example 24 hour mean blood pressure (ambulatory monitoring), Systemic endothelin-1 and big endothelin-1 concentrations and Changes in arterial stiffness (pulse-wave velocity).

What This Means in Plain Language

Put simply, this is a not phased, randomized trial of Endothelin-1 in 15 people.

Its size is small, so on its own it can only give an early look.

The trial is marked completed; no results are posted to the registry yet, so nothing here describes outcomes.

More context: the Endothelin-1 compound page, all human trials.