Antioxidant airway responses following experimental exposure to wood smoke in man

Abstract

BackgroundBiomass combustion contributes to the production of ambient particulate matter (PM) in rural environments as well as urban settings, but relatively little is known about the health effects of these emissions. The aim of this study was therefore to characterize airway responses in humans exposed to wood smoke PM under controlled conditions. Nineteen healthy volunteers were exposed to both wood smoke, at a particulate matter (PM2.5) concentration of 224 ± 22 μg/m3, and filtered air for three hours with intermittent exercise. The wood smoke was generated employing an experimental set-up with an adjustable wood pellet boiler system under incomplete combustion. Symptoms, lung function, and exhaled NO were measured over exposures, with bronchoscopy performed 24 h post-exposure for characterisation of airway inflammatory and antioxidant responses in airway lavages.ResultsGlutathione (GSH) concentrations were enhanced in bronchoalveolar lavage (BAL) after wood smoke exposure vs. air (p = 0.025), together with an increase in upper airway symptoms. Neither lung function, exhaled NO nor systemic nor airway inflammatory parameters in BAL and bronchial mucosal biopsies were significantly affected.ConclusionsExposure of healthy subjects to wood smoke, derived from an experimental wood pellet boiler operating under incomplete combustion conditions with PM emissions dominated by organic matter, caused an increase in mucosal symptoms and GSH in the alveolar respiratory tract lining fluids but no acute airway inflammatory responses. We contend that this response reflects a mobilisation of GSH to the air-lung interface, consistent with a protective adaptation to the investigated wood smoke exposure.

Health impacts of anthropogenic biomass burning in the developed world

“…Toxicological effects related to human health Human controlled exposure studies report that short-term inhalation of woodsmoke induces mild inflammatory effects including distal airway inflammation, increased oxidative stress and immune cell recruitment, but no effects on measures of lung function [98][99][100][101][102][103]. Studies also report systemic effects such as increased levels of coagulation markers, and decreased heart rate variability and systemic inflammation [100,[104][105][106][107].…”

Size-Resolved Respiratory Tract Deposition of Sub-Micrometer Aerosol Particles in a Residential Area with Wintertime Wood Combustion

“…Residential wood combustion has been associated with adverse health effects on a societal level in epidemiological studies as well as with more limited number of subjects in chamber exposure studies (Boman et al, 2003;Barregard, et al, 2006;Sehlstedt et al, 2010). There is, however, insufficient evidence available to decide whether particles from wood combustion are more or less toxic than other combustion-derived particles and ambient fine particles in general (Naeher et al, 2007).…”

Public health and components of particulate matter: The changing assessment of black carbon

“…Wood smoke has also been shown to alter airway responsiveness, inducing airway hyperreactivity in response to bronchoconstrictor challenge (Hus and Kou, 2001;Lin et al, 2001). However, results in controlled human exposures examining other ventilatory parameters have found no effect (Sehlstedt et al, 2010;Riddervold et al, 2012). However, in humans, wood smoke also resulted in increased serum amyloid A (SSA), an acute-phase protein that is often found to increase under conditions associated with inflammation and is a risk factor for CV morbidity (Ridker et al 2000) and may also play some role in development of atherosclerosis (Chait et al, 2005).…”