Size-partitioning of an urban aerosol to identify particle determinants involved in the proinflammatory response induced in airway epithelial cells

Ramgolam Kiran, Favez Olivier, Cachier Hélène, Gaudichet Annie, Marano Francelyne, Martinon Laurent, Baeza-Squiban, Baeza-Squiban Armelle

Description

The contribution of air particles in human cardio-respiratory diseases has been enlightened by several epidemiological studies. However the respective involvement of coarse, fine and ultrafine particles in health effects is still unclear. The aim of the present study is to determine which size fraction from a chemically characterized background aerosol has the most important short term biological effect and to decipher the determinants of such a behaviour. Results Ambient aerosols were collected at an urban background site in Paris using four 13-stage low pressure cascade impactors running in parallel (winter and summer 2005) in order to separate four size-classes (PM 0.03–0.17 (defined here as ultrafine particles), PM 0.17–1 (fine), PM 1–2.5 (intermediate) and PM 2.5–10 (coarse)). Accordingly, their chemical composition and their pro-inflammatory potential on human airway epithelial cells were investigated. Considering isomass exposures (same particle concentrations for each size fractions) the pro-inflammatory response characterized by Granulocyte Macrophage-Colony Stimulating Factor (GM-CSF) release was found to decrease with aerosol size with no seasonal dependency. When cells were exposed to isovolume of particle suspensions in order to respect the particle proportions observed in ambient air, the GM-CSF release was maximal with the fine fraction. In presence of a recombinant endotoxin neutralizing protein, the GM-CSF release induced by particles is reduced for all size-fractions, with exception of the ultra-fine fraction which response is not modified. The different aerosol size-fractions were found to display important chemical differences related to the various contributing primary and secondary sources and aerosol age. The GM-CSF release was correlated to the organic component of the aerosols and especially its water soluble fraction. Finally, Cytochrome P450 1A1 activity that reflects PAH bioavailability varied as a function of the season: it was maximal for the fine fraction in winter and for the ultrafine fraction in summer. Conclusion In the frame of future regulations, a particular attention should thus be paid to the ultrafine/fine (here referred to as PM1) fraction due to their overwhelming anthropogenic origin and predominance in the urban aerosol and their pro-inflammatory potential.

Informations

• Publié par: biomed
• Publié le: 01 janvier 2009
• Nombre de lectures: 17
• Langue: English
• Poids de l'ouvrage: 1 Mo

Extrait

Particle and Fibre Toxicology

BioMedCentral

Open Access Research Sizepartitioning of an urban aerosol to identify particle determinants involved in the proinflammatory response induced in airway epithelial cells †1 †22 3 Kiran Ramgolam, Olivier Favez, Hélène Cachier, Annie Gaudichet, 1 41 Francelyne Marano, Laurent Martinonand Armelle BaezaSquiban*

1 Address: UnivParis Diderot, Paris 7, Laboratory of Molecular and Cellular Responses to Xénobiotics, Unit of Functional and Adaptive Biology 2 affiliated to CNRS, 5 rue Thomas Mann, case courrier 7073, 75013 Paris, France,Laboratoire des Sciences du Climat et de l'Environnement (LSCE/ 3 IPSL), Laboratoire CEACNRSUVSQ, CEA Orme des Merisiers, 91191 GifsurYvette, France,Laboratoire Interuniversitaire des Systèmes 4 Atmosphériques (LISA), Université Paris 12, 61 avenue du Général de Gaulle, 94010 Créteil Cedex, France andLaboratoire d'Etude des Particules Inhalées (LEPI), Ville de Paris, 11 rue George Eastman, 75013 Paris, France

Email: Kiran Ramgolam  kiran.ramgolam@univparisdiderot.fr; Olivier Favez  [e-mail]lyon1.fr; Hélène Cachier  [e-mail]; Annie Gaudichet  [e-mail]; Francelyne Marano  marano@univparisdiderot.fr; Laurent Martinon  [e-mail]; Armelle BaezaSquiban*  baeza@univparisdiderot.fr * Corresponding author†Equal contributors

Published: 23 March 2009Received: 8 December 2008 Accepted: 23 March 2009 Particle and Fibre Toxicology2009,6:10 doi:10.1186/17438977610 This article is available from: http://www.particleandfibretoxicology.com/content/6/1/10 © 2009 Ramgolam et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract Background:The contribution of air particles in human cardiorespiratory diseases has been enlightened by several epidemiological studies. However the respective involvement of coarse, fine and ultrafine particles in health effects is still unclear. The aim of the present study is to determine which size fraction from a chemically characterized background aerosol has the most important short term biological effect and to decipher the determinants of such a behaviour. Results:Ambient aerosols were collected at an urban background site in Paris using four 13stage low pressure cascade impactors running in parallel (winter and summer 2005) in order to separate four sizeclasses (PM(defined here 0.03–0.17 as ultrafine particles), PM(fine), PM(intermediate) and PM(coarse)). Accordingly, their chemical 0.17–1 1–2.52.5–10 composition and their proinflammatory potential on human airway epithelial cells were investigated. Considering isomass exposures (same particle concentrations for each size fractions) the proinflammatory response characterized by Granulocyte MacrophageColony Stimulating Factor (GMCSF) release was found to decrease with aerosol size with no seasonal dependency. When cells were exposed to isovolume of particle suspensions in order to respect the particle proportions observed in ambient air, the GMCSF release was maximal with the fine fraction. In presence of a recombinant endotoxin neutralizing protein, the GMCSF release induced by particles is reduced for all sizefractions, with exception of the ultrafine fraction which response is not modified. The different aerosol sizefractions were found to display important chemical differences related to the various contributing primary and secondary sources and aerosol age. The GMCSF release was correlated to the organic component of the aerosols and especially its water soluble fraction. Finally, Cytochrome P450 1A1 activity that reflects PAH bioavailability varied as a function of the season: it was maximal for the fine fraction in winter and for the ultrafine fraction in summer. Conclusion:In the frame of future regulations, a particular attention should thus be paid to the ultrafine/fine (here referred to as PM1) fraction due to their overwhelming anthropogenic origin and predominance in the urban aerosol and their proinflammatory potential.

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