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

Ramgolam K, Favez O, Cachier H, Gaudichet A, Marano F, Martinon L, Baeza-Squiban A - Part Fibre Toxicol (2009)

Bottom Line: However the respective involvement of coarse, fine and ultrafine particles in health effects is still unclear.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.

View Article: PubMed Central - HTML - PubMed

Affiliation: Univ Paris Diderot, Paris 7, Laboratory of Molecular and Cellular Responses to Xénobiotics, Unit of Functional and Adaptive Biology affiliated to CNRS, 5 rue Thomas Mann, case courrier 7073, 75013 Paris, France. baeza@univ-paris-diderot.fr.

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 (PM0.03-0.17 (defined here as ultrafine particles), PM0.17-1 (fine), PM1-2.5(intermediate) and PM2.5-10 (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.

No MeSH data available.


Related in: MedlinePlus

Mass size distributions of the aerosol mass in winter and summer aerosols. Using an inversion program described in Gomes et al., 1990 [38], raw data averaged for winter and summer separately (purple dashed lines) were inverted. The figure presents log-normal mass size distribution of the total aerosol (black plain line) and sorts out the three main contributions (Aitken, accumulation and coarse modes).
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Figure 1: Mass size distributions of the aerosol mass in winter and summer aerosols. Using an inversion program described in Gomes et al., 1990 [38], raw data averaged for winter and summer separately (purple dashed lines) were inverted. The figure presents log-normal mass size distribution of the total aerosol (black plain line) and sorts out the three main contributions (Aitken, accumulation and coarse modes).

Mentions: Mass concentration and contribution to PM10 are reported for each class-size fraction in Table 1. Results unambiguously underline the predominance of the fine fraction (PM0.17–1, 53 ± 13%). Data inversion for the seven LPI samples point to three main aerosol modes, namely the Aitken mode, the accumulation mode and the coarse mode with a geometric mean aerosol equivalent diameter (AED) of approximately 100 nm, 450 nm and 3 μm respectively. As presented in Figure 1, the threshold value between the accumulation and the coarse modes is found to be approximately 1.5 μm in winter and 1.2 μm in summer supporting our decision to study four different size fractions i.e. the ultrafine (PM0.03–0.17), fine (PM0.17–1), intermediate (PM1–2.5) and coarse (PM2.5–10) fractions. It has to be noted that aerosol collection with low-pressure cascade impactors may underestimate the smaller size-fractions of the aerosol mainly due to the evaporation of semi-volatile material from particles accumulated on the filters [19]. For PM2.5, this artefact was evaluated by comparison with TEOM/FDMS (artefact free) data and found to be of the order of 7%. However, particle loss underestimate is expected to be higher for ultrafine particles collected on the first stages of the impactor under significant vacuum conditions which suggests that this aerosol fraction could be still more reactive under isovolume condition.


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

Ramgolam K, Favez O, Cachier H, Gaudichet A, Marano F, Martinon L, Baeza-Squiban A - Part Fibre Toxicol (2009)

Mass size distributions of the aerosol mass in winter and summer aerosols. Using an inversion program described in Gomes et al., 1990 [38], raw data averaged for winter and summer separately (purple dashed lines) were inverted. The figure presents log-normal mass size distribution of the total aerosol (black plain line) and sorts out the three main contributions (Aitken, accumulation and coarse modes).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2667424&req=5

Figure 1: Mass size distributions of the aerosol mass in winter and summer aerosols. Using an inversion program described in Gomes et al., 1990 [38], raw data averaged for winter and summer separately (purple dashed lines) were inverted. The figure presents log-normal mass size distribution of the total aerosol (black plain line) and sorts out the three main contributions (Aitken, accumulation and coarse modes).
Mentions: Mass concentration and contribution to PM10 are reported for each class-size fraction in Table 1. Results unambiguously underline the predominance of the fine fraction (PM0.17–1, 53 ± 13%). Data inversion for the seven LPI samples point to three main aerosol modes, namely the Aitken mode, the accumulation mode and the coarse mode with a geometric mean aerosol equivalent diameter (AED) of approximately 100 nm, 450 nm and 3 μm respectively. As presented in Figure 1, the threshold value between the accumulation and the coarse modes is found to be approximately 1.5 μm in winter and 1.2 μm in summer supporting our decision to study four different size fractions i.e. the ultrafine (PM0.03–0.17), fine (PM0.17–1), intermediate (PM1–2.5) and coarse (PM2.5–10) fractions. It has to be noted that aerosol collection with low-pressure cascade impactors may underestimate the smaller size-fractions of the aerosol mainly due to the evaporation of semi-volatile material from particles accumulated on the filters [19]. For PM2.5, this artefact was evaluated by comparison with TEOM/FDMS (artefact free) data and found to be of the order of 7%. However, particle loss underestimate is expected to be higher for ultrafine particles collected on the first stages of the impactor under significant vacuum conditions which suggests that this aerosol fraction could be still more reactive under isovolume condition.

Bottom Line: However the respective involvement of coarse, fine and ultrafine particles in health effects is still unclear.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.

View Article: PubMed Central - HTML - PubMed

Affiliation: Univ Paris Diderot, Paris 7, Laboratory of Molecular and Cellular Responses to Xénobiotics, Unit of Functional and Adaptive Biology affiliated to CNRS, 5 rue Thomas Mann, case courrier 7073, 75013 Paris, France. baeza@univ-paris-diderot.fr.

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 (PM0.03-0.17 (defined here as ultrafine particles), PM0.17-1 (fine), PM1-2.5(intermediate) and PM2.5-10 (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.

No MeSH data available.


Related in: MedlinePlus