BD100: Health Effects of Biodiesel Exhaust Exposure

Sponsor

Umeå University (Other)

Overall Status

Completed

CT.gov ID

NCT01883466

Collaborator

University of Edinburgh (Other)

Enrollment

Location

Arms

Duration (Months)

2.7

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

Urban air pollution is a major contributor to greenhouse gases and has been shown to increase cardiovascular mortality and morbidity. This century has seen a rebirth of biofuel marketing and research, with biodiesel emerging as one of the strongest contenders within international markets. The pursuit of alternative renewable fuels is incredibly complex and has powered research in agriculture, biotechnology, production, transportation, feedstocks, ecology and biomass manufacturing. In spite of this, health effects have been an almost completely overlooked aspect. The purpose of this study is to investigate whether 100% biodiesel exhaust exposure in healthy volunteers leads to cardiovascular and inflammatory responses. Further investigations into the chemical composition of biodiesel exhaust will also be performed.

Condition or Disease	Intervention/Treatment	Phase
Vascular Endothelium	Other: Forearm venous occlusion plethysmography study	N/A

Study Design

Study Type:

Interventional

Actual Enrollment :

19 participants

Allocation:

Randomized

Intervention Model:

Crossover Assignment

Masking:

Triple (Participant, Investigator, Outcomes Assessor)

Primary Purpose:

Basic Science

Official Title:

Cardiovascular Effects of Exposure to 100% Biodiesel Exhaust in Man

Study Start Date :

Sep 1, 2012

Actual Primary Completion Date :

Jan 1, 2013

Actual Study Completion Date :

Apr 1, 2013

Arms and Interventions

Arm	Intervention/Treatment
Experimental: Diesel exhaust exposure 1 hour exposure to dilute diesel exhaust (approximate particle matter concentration 300 mcg/m3) during intermittent exercise	Other: Forearm venous occlusion plethysmography study Measurement of forearm blood flow during unilateral intrabrachial infusion of four vasodilator drugs in incremental doses separated with 20-min washout periods. Bradykinin (endothelial-dependent vasodilator that releases t-PA) was infused at 100, 300 and 1000 pmol/min; acetylcholine (endothelial independent vasodilator that does not release t-PA) was infused at 5, 10 and 20 mcg/min; sodium nitroprusside (endothelial independent vasodilator that does not release t-PA) was infused at 2, 4 and 8 mcg/min and verapamil (endothelial independent and NO independent vasodilator that does not release t-PA) was infused at 10, 30 and 100 mcg/min. Bradykinin, acetylcholine and sodium nitroprusside were given in random order and verapamil was administered last due to its long acting effects.
Experimental: Biodiesel exhaust exposure 1 hour exposure to dilute biodiesel exhaust (generated at same running conditions as diesel exhaust) during intermittent exercise	Other: Forearm venous occlusion plethysmography study Measurement of forearm blood flow during unilateral intrabrachial infusion of four vasodilator drugs in incremental doses separated with 20-min washout periods. Bradykinin (endothelial-dependent vasodilator that releases t-PA) was infused at 100, 300 and 1000 pmol/min; acetylcholine (endothelial independent vasodilator that does not release t-PA) was infused at 5, 10 and 20 mcg/min; sodium nitroprusside (endothelial independent vasodilator that does not release t-PA) was infused at 2, 4 and 8 mcg/min and verapamil (endothelial independent and NO independent vasodilator that does not release t-PA) was infused at 10, 30 and 100 mcg/min. Bradykinin, acetylcholine and sodium nitroprusside were given in random order and verapamil was administered last due to its long acting effects.

Arm

Intervention/Treatment

Experimental: Diesel exhaust exposure

1 hour exposure to dilute diesel exhaust (approximate particle matter concentration 300 mcg/m3) during intermittent exercise

Other: Forearm venous occlusion plethysmography study

Measurement of forearm blood flow during unilateral intrabrachial infusion of four vasodilator drugs in incremental doses separated with 20-min washout periods. Bradykinin (endothelial-dependent vasodilator that releases t-PA) was infused at 100, 300 and 1000 pmol/min; acetylcholine (endothelial independent vasodilator that does not release t-PA) was infused at 5, 10 and 20 mcg/min; sodium nitroprusside (endothelial independent vasodilator that does not release t-PA) was infused at 2, 4 and 8 mcg/min and verapamil (endothelial independent and NO independent vasodilator that does not release t-PA) was infused at 10, 30 and 100 mcg/min. Bradykinin, acetylcholine and sodium nitroprusside were given in random order and verapamil was administered last due to its long acting effects.

Experimental: Biodiesel exhaust exposure

1 hour exposure to dilute biodiesel exhaust (generated at same running conditions as diesel exhaust) during intermittent exercise

Other: Forearm venous occlusion plethysmography study

Outcome Measures

Primary Outcome Measures

Vascular vasomotor and fibrinolytic function [4-6 hours after exposure]
Forearm venous occlusion plethysmography to measure forearm blood flow during unilateral intrabrachial infusion of endothelial-dependent and -independent vasodilators (bradykinin & acetylcholine and sodium nitroprusside & verapamil respectively). Tissue plasminogen activator and plasminogen activator inhibitor-1 were analysed in blood samples taken after bradykinin infusions in order to assess fibrinolytic function. These composite outcome measures will together indicate vascular vasomotor function.

Secondary Outcome Measures

Respiratory function tests [Baseline, 6 and 24 hours after exposure]
Basic spirometry and fraction of exhaled nitric oxide (FeNO) are performed at baseline, as well as 6 and 24 hours after exposure.
Effects of exposure on metabolomic markers in plasma [Baseline and 2, 4 & 24 hours after exposure]
Blood samples taken at baseline as well as at 2, 4 and 24 hours post-exposure will be stored as plasma for metabolomic analysis. Since inflammatory mediators such as eicosanoids and other fatty acid metabolites have been seen as likely key players in air pollution response, particular interest will be directed towards the oxylipin metabolome, which will be analyzed according to established protocols. These samples are taken in EDTA tubes and placed on ice. They are centrifuged at a low temperature and then divided into 1ml allotments. These are then stored in a freezer until analysis.

Eligibility Criteria

Criteria

Ages Eligible for Study:

18 Years to 60 Years

Sexes Eligible for Study:

Male

Accepts Healthy Volunteers:

Yes

Inclusion Criteria:

Non-smoking, healthy male subjects. All subjects undergo a general health examination and are required to have normal clinical examination, ECG, blood tests and lung function.

Exclusion Criteria:

Diabetes Mellitus
Cardiovascular disease
Asthma
Respiratory infection within 2 weeks of the study
Antioxidant- and/or vitamin supplementation within 1 week prior to, as well as during the course of the study. (incl vitamin C, Acetylcysteine)
Smokers or regular snus usage