Importance of Size and Composition of Particles for Effects on Cells In Vitro

Abstract

A primary goal of current research on particle-induced health effects is to reveal the critical characteristics that determine their biological effects. Experimental studies have shown that smaller particles induce stronger biological effects than larger particles of similar composition, due to their larger surface area to mass ratio. However, correlation for variations in surface area could not account for variation in biological reactivity among particles of differential composition. Hence, the importance of size and surface area does not override the importance of particle composition. Moreover, different particle characteristics appear to be involved in different biological effects in vitro. Our studies show that mineral particle-induced apoptosis mostly seems to depend on particle size, whereas composition and surface reactivity appeared to be most important for the proinflammatory potential of the particles. The ability of the particles to generate reactive oxygen species in vitro was not correlated with either inflammatory markers or apoptosis, suggesting that other mechanisms are at play. A single, specific component of the mineral particles, explaining the differences in response, has not been identified. In European-wide studies such as the Respiratory Allergy and Inflammation due to Air Pollution (RAIAP) study, particles have been sampled in different locations to study season- and site-dependent variations in responses particles, such as markers of inflammatory and allergic reactions in cells and animals. The data indicate that coarse particles can induce at least as strong inflammatory responses as fine particles. The allergic responses tended to be more associated with the organic fraction (PAH) of particles, whereas the inflammatory reactions seemed to be more associated with metals and endotoxin. Overall, coarse PM was found to have an inflammatory potential similar to fine PM on an equal mass basis. Even though one has to take into account different concentrations in ambient air as well as differences in respiratory system deposition of the size fractions, the potential of coarse particles to induce pulmonary effects should not be neglected.

Cytotoxic response in human lung epithelial cells and ion characteristics of urban-air particles from Torino, a northern Italian city

“…bronchitis and asthma, and changes in heart rate variability (Dominici et al 2007 ;Peacock et al 2011 ;Pope et al 2009 ;Raaschou-Nielsen et al 2011 ;Rusconi et al 2011 ). However, fundamental uncertainties still exist with respect to the underlying mechanisms of toxicity that are responsible for the mortality or morbidity increases following exposure to current levels of air pollution PM (Schwarze et al 2007 ).…”

“…However, under abnormal conditions, excessive levels of ROS exceed the detoxification capacity of the antioxidant defences, thereby causing a change in the redox status of the cell (Jomova and Valko 2011 ;Lonkar and Dedon 2011 ;Ziech et al 2011 ). Oxidative stress subsequently triggers a cascade of events closely associated with inflammation, which is believed to play a key role in the air pollution/PM-induced development and/or exacerbation of acute and/or chronic lung diseases (Dagher et al 2005' Lodovici and Bigagli 2011Oh et al 2011 ;Schwarze et al 2007 ). Transition metals (i.e.…”

Important research questions in allergy and related diseases: nonallergic rhinitis: a GA2LEN paper

“…These include the ECRHS-I and II (FP3, FP4 and FP5) (38,139), AIRALLERG (Effects of outdoor and indoor air pollution on the development of allergic disease in children, FP5) (140,141), Health effects of particles from motor engine exhaust and ambient air pollution, FP5 (142), PATY (Pollution and the young combined analyses of cross-sectional studies of respiratory health of children and air pollution, FP5) (143)(144)(145) and Respiratory Allergy and Inflammation due to Air Pollution (FP5) (146). BioAir (FP5), a longitudinal assessment of clinical course and biomarkers in severe chronic airway disease, has used modern clinical measurements and the exploitation of new molecular methods to define biomarkers of chronic airway inflammation and remodeling.…”

Source apportionment of elevated wintertime PAHs by compound-specific radiocarbon analysis

“…Some PAHs are very well known carcinogens and several studies indicate a negative impact of atmospheric PAHs on human and ecological health (Busby et al, 1997;Hedberg and Johansson, 2006;Choi et al, 2006;Sauvain et al, 2003;Schwarze et al, 2007). To abate the adverse health effects caused by these pollutants, source apportionment studies are needed to inform effective strategies and air quality regulations to control PAH emissions.…”