Acute Exposure to Diesel: Prolong Effects on Inflammation and Vasculature

Introduction Diesel and its products represent one of the most common pollutants affecting people living in urban and rural areas of the world. The majority of patients attending emergency departments are likely to have been subjected to chronic exposure to diesel engine exhaust fumes particularly those living in proximity to busy city roads and highways. Diesel exhaust fumes are considered to contribute to over 50% of atmospheric particles with a mass of less than 10 μM (PM10) average aerodynamic diameter, which is responsible for air pollution. For fine particle matter lower than 2.5 μM (PM2.5) and extremely small particles below 0.1 μM in diameter, the contribution to air pollution is much greater. These particles are small enough to be inhaled and deposited in the lungs where they can exert deleterious effects.

In Europe and Japan, epidemiological studies have demonstrated high rates of cardiovascular morbidity, as well as acute and chronic respiratory disease, following occupational exposure to diesel exhaust fumes. Experimental animal studies have also shown that exposure to diluted diesel engine emission impairs left ventricle systolic performance, sympathetic drive, fibrosis/fibrinolysis and accelerates atherosclerosis. Epidemiological studies and experimental animal models are, however, rather imprecise regarding the mechanisms responsible for these effects and the clinical impact of chronic diesel exhaust fumes exposure. Moreover, although a relationship has been documented between acute coronary syndromes (ACS) and acute exposure to diesel engine exhaust fumes, it is not known whether relatively short-term exposure can cause prolonged inflammatory responses and/or affect endothelial function and vessel wall properties in such a way as to potentially promote the development of atherosclerotic changes.

The purpose of this study is to assess the impact of short-term exposure to Diesel exhaust fumes on arterial elasticity, vascular function and inflammatory biomarkers.

Methods Study population Volunteers will be included in this randomized, double blind, crossover study All volunteers who qualified for study entry will be free of cardiovascular disease, hypertension, diabetes mellitus, pulmonary disease and acute inflammatory or chronic diseases. Subjects who will be found to have an abnormal baseline 12-lead electrocardiogram and/or impaired respiratory function tests will be excluded from the study.

Individuals taking cardiovascular medications, antioxidant or vitamin supplementation, oral contraceptives or anti-inflammatory agents during the two months prior to inclusion in the study will be excluded.