Biodiesel Exhaust, Acute Vascular and Endothelial Responses

University of Edinburgh16 enrolled

Overview

Exposure to particulate air pollution has been shown to increase cardiovascular mortality and morbidity, and in previous controlled exposure studies has been shown to have acute cardiovascular and respiratory effects. The last decade has seen an unprecedented drive towards finding a bioeconomical and renewable source of fuel in order to reduce our dependence on fossil fuels. Although both biodiesel and bioethanol have emerged as contenders for future fuels, biodiesel remains as the strongest contender within European markets. In 2007 researchers at the EPA released a commentary, which concluded that the assumed correlation between the chemical composition of biodiesel exhaust and a reduction in health effects was only hypothetical. They suggested that there was a clear need for the study of health effects in humans regarding biofuel exhaust. In this project the investigators aim to investigate the cardiovascular, respiratory and inflammatory responses to biofuel exhaust exposure in healthy volunteers.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

TRIPLE

Enrollment

Conditions

Healthy

Interventions

Forearm venous occlusion plethysmography to measure forearm blood flow during unilateral intrabrachial infusion of endothelium-dependent (bradykinin \[100, 300 \& 1000 pmol/min\]; acetylcholine \[5, 10 \& 20 µg/min\]) and -independent \[sodium nitroprusside \[2, 4 \& 8 µg/min\]; verapamil \[10, 30 \& 100 µg/min\]) vasodilators. Each drug to be infused for 6 mins at each dose in increasing concentrations. 0.9% sodium chloride will be infused for 20 min between each individual drug to allow washout.

Eligibility

Sex: ALLMin age: 20 YearsMax age: 55 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * 20 healthy, non-smoking subjects, age 20-55 year old, both genders. All subjects undergo a general health examination and are required to have: Normal clinical examination Normal EKG Normal routine blood tests Normal lung function Exclusion Criteria: * Cardiovascular disease * Diabetes Mellitus * Asthma and/or allergy * Respiratory infection within 3 weeks of the study * Antioxidant- and/or vitamin supplementation within 2 weeks prior to, as well as during the course of the study. (incl vitamin C, Acetylcysteine) * Female subjects will take a urinary pregnancy test before each exposure and will be excluded if this is positive.

Outcomes

Primary Outcomes

Vascular vasomotor and fibrinolytic function

Forearm venous occlusion plethysmography to measure forearm blood flow during unilateral intrabrachial infusion of endothelial-dependent (bradykinin and acetylcholine) and -independent (sodium nitroprusside and verapamil) vasodilators. Fibrinolytic function assessed by blood sampling after infusion of bradykinin for tissue plasminogen activator and plasminogen activator inhibitor-1.

Time frame: 4-6 hours after exposure

Secondary Outcomes

Respiratory function tests

Basic spirometry will be performed at baseline and 6 hours after each exposure

Time frame: 6 hours after exposure

Inflammatory markers

Blood samples will be taken and stored as plasma and serum for measurement of inflammatory mediators

Time frame: Baseline and up to 24 hours after exposure

Central arterial stiffness

Central arterial stiffness (PWV and PWA) will be measured at baseline and immediately after the exposure

Time frame: Baseline and post exposure