Airway inflammation following exposure to diesel exhaust: a study of time kinetics using induced sputum.

The adverse health effects of particulate matter pollution are of increasing concern. In a recent bronchoscopic study in healthy volunteers, pronounced airway inflammation was detected following exposure to diesel exhaust (DE). The present study was conducted in order to evaluate the time kinetics of the inflammatory response following exposure to DE using induced sputum from healthy volunteers. Fifteen healthy nonsmoking volunteers were exposed to DE particles with a 50% cut-off aerodynamic diameter of 10 microm 300 microg x m(-3) and air for 1 h on two separate occasions. Sputum induction with hypertonic saline was performed 6 and 24 h after each exposure. Analyses of sputum differential cell counts and soluble protein concentrations were performed. Six hours after exposure to DE, a significant increase was found in the percentage of sputum neutrophils (37.7 versus 26.2% p=0.002) together with increases in the concentrations of interleukin-6 (12.0 versus 6.3 pg x mL(-1), p=0.006) and methylhistamine (0.11 versus 0.12 microg x L(-1), p=0.024). Irrespective of exposure, a significant increase was found in the percentage of sputum neutrophils at 24 as compared to 6 h, indicating that the procedure of sputum induction itself may change the composition of sputum. This study demonstrates that exposure to diesel exhaust induces inflammatory response in healthy human airways, represented by an early increase in interleukin-6 and methylhistamine concentration and the percentage of neutrophils. Induced sputum provides a safe tool for the investigation of the inflammatory effects of diesel exhaust, but care must be taken when interpreting results from repeated sputum inductions.

[1]  C. Pope,et al.  Health effects of particulate air pollution: time for reassessment? , 1995, Environmental health perspectives.

[2]  F. Hargreave,et al.  Indices of airway inflammation in induced sputum: reproducibility and validity of cell and fluid-phase measurements. , 1996, American journal of respiratory and critical care medicine.

[3]  C. Giuntini,et al.  Effect of short-term NO2 exposure on induced sputum in normal, asthmatic and COPD subjects. , 1996, The European respiratory journal.

[4]  U. Ulfvarson,et al.  Pulmonary function in workers exposed to diesel exhausts: the effect of control measures. , 1991, American journal of industrial medicine.

[5]  Vostal Jj,et al.  Health aspects of diesel exhaust particulate emissions. , 1980 .

[6]  H. Boushey,et al.  Comparison of samples collected by sputum induction and bronchoscopy from asthmatic and healthy subjects. , 1995, American journal of respiratory and critical care medicine.

[7]  R. Devlin,et al.  Air pollution particles induce IL-6 gene expression in human airway epithelial cells via NF-kappaB activation. , 1998, American journal of respiratory cell and molecular biology.

[8]  J Merchant,et al.  Coal miners exposed to diesel exhaust emissions. , 1982, The Annals of occupational hygiene.

[9]  H. Boushey,et al.  Analysis of cellular and biochemical constituents of induced sputum after allergen challenge: a method for studying allergic airway inflammation. , 1994, The Journal of allergy and clinical immunology.

[10]  J. Carter,et al.  Cytokine production by human airway epithelial cells after exposure to an air pollution particle is metal-dependent. , 1997, Toxicology and applied pharmacology.

[11]  J. Gamble,et al.  Epidemiological-environmental study of diesel bus garage workers: acute effects of NO2 and respirable particulate on the respiratory system. , 1987, Environmental research.

[12]  H. Boushey,et al.  Analysis of induced sputum after air and ozone exposures in healthy subjects. , 1995, Environmental research.

[13]  T. Sandstrom,et al.  Controlled diesel exhaust exposure in an exposure chamber: pulmonary effects investigated with bronchoalveolar lavage , 1990 .

[14]  D. Díaz-Sánchez,et al.  The role of diesel exhaust particles and their associated polyaromatic hydrocarbons in the induction of allergic airway disease. , 1997, Allergy.

[15]  T. Sandström,et al.  Bronchoalveolar inflammation after exposure to diesel exhaust: comparison between unfiltered and particle trap filtered exhaust. , 1999, Occupational and environmental medicine.

[16]  T. Sandström,et al.  Evaluation of an exposure setup for studying effects of diesel exhaust in humans , 1994, International archives of occupational and environmental health.

[17]  P. Barnes,et al.  Effect of repeated sputum induction on cell counts in normal volunteers. , 1998, Thorax.

[18]  T. Sandström,et al.  Effects on symptoms and lung function in humans experimentally exposed to diesel exhaust. , 1996, Occupational and environmental medicine.

[19]  J Schwartz,et al.  Air pollution and daily mortality in Birmingham, Alabama. , 1993, American journal of epidemiology.

[20]  B. Ostro,et al.  The association of air pollution and mortality: examining the case for inference. , 1993, Archives of environmental health.

[21]  H. van Loveren,et al.  Diesel exhaust particles induced release of interleukin 6 and 8 by (primed) human bronchial epithelial cells (BEAS 2B) in vitro. , 1997, Experimental lung research.

[22]  J. Denburg,et al.  Use of induced sputum cell counts to investigate airway inflammation in asthma. , 1992, Thorax.

[23]  A. Saxon,et al.  Diesel exhaust particles induce local IgE production in vivo and alter the pattern of IgE messenger RNA isoforms. , 1994, The Journal of clinical investigation.

[24]  Todor A Popov,et al.  Spontaneous and induced sputum to measure indices of airway inflammation in asthma. , 1996, American journal of respiratory and critical care medicine.

[25]  T. Sandström,et al.  Acute inflammatory responses in the airways and peripheral blood following short-term exposure to diesel exhaust in healthy human subjects. , 1999 .

[26]  S. Akira,et al.  Interleukin-6 and its receptor: a paradigm for cytokines. , 1992, Science.

[27]  P. Sterk,et al.  Comparison of inflammatory cell counts in asthma: induced sputum vs bronchoalveolar lavage and bronchial biopsies , 1997, Clinical and experimental allergy : journal of the British Society for Allergy and Clinical Immunology.

[28]  H. Boushey,et al.  Cellular and biochemical analysis of induced sputum from asthmatic and from healthy subjects. , 1993, The American review of respiratory disease.

[29]  H. Magnussen,et al.  Changes in sputum composition between two inductions performed on consecutive days. , 1998, Thorax.

[30]  D. Diat-Sanchez,et al.  The role of diesel exhaust particles and their associated polyaromatic hydrocarbons in the induction of allergic airway disease , 1997 .

[31]  J. Schwartz,et al.  Particulate air pollution and daily mortality in Detroit. , 1991, Environmental research.

[32]  D. Dockery,et al.  An association between air pollution and mortality in six U.S. cities. , 1993, The New England journal of medicine.

[33]  I. Pavord,et al.  The use of induced sputum to investigate airway inflammation. , 1997, Thorax.

[34]  S T Holgate,et al.  Acute inflammatory responses in the airways and peripheral blood after short-term exposure to diesel exhaust in healthy human volunteers. , 1999, American journal of respiratory and critical care medicine.

[35]  D. Dockery,et al.  Particulate air pollution and daily mortality in Steubenville, Ohio. , 1992, American journal of epidemiology.