Effects of Ambient Air Particulate Exposure on Blood–Gas Barrier Permeability and Lung Function

Abstract

Particulate air pollution is associated with increased risk of pulmonary diseases and detrimental outcomes related to the cardiovascular system, including altered vessel functions. This study's objective was too evaluate the effects of ambient particle exposure on the blood-gas permeability, lung function and Clara cell 16 (CC16) protein release in healthy young subjects. Twenty-nine nonsmokers participated in a randomized, two-factor crossover study with or without biking exercise for 180 min and with 24-h exposure to particle-rich (6169-15,362 particles/cm 3 ; 7.0-11.6 µg/m 3 PM 2.5 ; 7.5-15.8 µg/m 3 PM 10−2.5 ) or filtered (91-542 particles/cm 3 ) air collected above a busy street. The clearance rate of aerosolized 99m Tc-labeled diethylenetriamine pentaacetic acid ( 99m Tc-DTPA) was measured as an index for the alveolar epithelial membrane integrity and permeability of the lung blood-gas barrier after rush-hour exposure. Lung function was assessed using body plethysmography, flowvolume curves, and measurements of the diffusion capacity of carbon monoxide. CC16 was measured in plasma and urine as another marker of alveolar integrity. Particulate matter exposure had no significant effect on the epithelial membrane integrity using the methods available in this study. Exercise increased the clearance rate of 99m Tc-DTPA indicated by a 6.8% (95% CI: 0.4-12.8%) shorter half-life and this was more pronounced in men than women. Neither particulate matter exposure nor exercise had an effect on the concentration of CC16 in plasma and urine or on the static and dynamic volumes or ventilation distribution of the lungs. The study thus demonstrates increased permeability of the alveolar blood-gas barrier following moderate exercise, whereas exposure to ambient levels of urban air particles has no detectable effects on the alveolar blood-gas barrier or lung function.

Cardiovascular and lung function in relation to outdoor and indoor exposure to fine and ultrafine particulate matter in middle-aged subjects

“…An exposure contrast in PNC (9000-66,500 particles/cm 3 ) for 5 h while exercising intermittently at five different locations including two traffic sites, an urban background location, an underground train station and a farm in the Netherlands was associated with decreased lung function in young healthy subjects (Strak et al, 2012). However, in healthy young adults no effect on lung function was observed during 24 h of exposure to air from a busy street in Copenhagen, Denmark, with PNC of 6000-15,000 particles/cm 3 (Brauner et al, 2009). Similarly, a 2-hour exposure to high PNC in a road tunnel (1.3 × 10 5 particles/mL) or concentrated ambient UFP (2.1 × 10 5 particles/cm 3 ) were not associated with altered lung function in young and healthy subjects (Larsson et al, 2007;Samet et al, 2009).…”

Pulmonary responses in current smokers and ex-smokers following a two hour exposure at rest to clean air and fine ambient air particles

“…Inhalation of fine iron oxide particles (12.7 mg/m 3 ) for 30 min at rest by healthy young volunteers had no significant effects on D L CO and DTPA clearance half-time either at 0.5 or 24 h post inhalation [21]. Prolonged 24 h chamber exposure of young healthy exercising individuals to predominantly coarse ambient PM failed to have any significant effects on the blood-gas barrier as measured by DTPA clearance rate [22]. Other studies, however, have shown increased epithelial permeability as assessed by DTPA clearance rate in smokers vs. nonsmokers [23,24].…”

Effects on airways of short-term exposure to two kinds of wood smoke in a chamber study of healthy humans

“…Cigarette smokers have instead lower S-CC16 due to loss of Clara cells by long-term exposure (Bernard et al, 1994, Shijubo et al, 1997, Hermans et al, 1998, Ellingsen et al, 2010. Some air pollution studies have seen an effect on U-CC16 (Timonen et al, 2004, Barregard et al, 2008, Jacquemin et al, 2009) while others have not (Bräuner et al, 2009).…”