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Chlamydophila pneumoniae induces a sustained airway hyperresponsiveness and inflammation in mice.

Blasi F, Aliberti S, Allegra L, Piatti G, Tarsia P, Ossewaarde JM, Verweij V, Nijkamp FP, Folkerts G - Respir. Res. (2007)

Bottom Line: From day 7 to 21 epithelial damage and secretory cell hypertrophy was observed.It is suggested that, the inflammatory cells/mediators, the epithelial damage and secretory cell hypertrophy contribute to initiation of airway hyperresponsiveness.This has clinical implications, since additional changes in airway responsiveness and inflammation-status induced by this bacterium may worsen and/or provoke breathlessness in asthma and COPD.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Respiratory Diseases, University of Milan, IRCCS Ospedale Maggiore Fondazione Policlinico-Mangiagalli-Regina Elena, Milano, Italy. francesco.blasi@unimi.it

ABSTRACT

Background: It has been reported that Chlamydophila (C.) pneumoniae is involved in the initiation and promotion of asthma and chronic obstructive pulmonary diseases (COPD). Surprisingly, the effect of C. pneumoniae on airway function has never been investigated.

Methods: In this study, mice were inoculated intranasally with C. pneumoniae (strain AR39) on day 0 and experiments were performed on day 2, 7, 14 and 21.

Results: We found that from day 7, C. pneumoniae infection causes both a sustained airway hyperresponsiveness and an inflammation. Interferon-gamma (IFN-gamma) and macrophage inflammatory chemokine-2 (MIP-2) levels in bronchoalveolar lavage (BAL)-fluid were increased on all experimental days with exception of day 7 where MIP-2 concentrations dropped to control levels. In contrast, tumor necrosis factor-alpha (TNF-alpha) levels were only increased on day 7. From day 7 to 21 epithelial damage and secretory cell hypertrophy was observed. It is suggested that, the inflammatory cells/mediators, the epithelial damage and secretory cell hypertrophy contribute to initiation of airway hyperresponsiveness.

Conclusion: Our study demonstrates for the first time that C. pneumoniae infection can modify bronchial responsiveness. This has clinical implications, since additional changes in airway responsiveness and inflammation-status induced by this bacterium may worsen and/or provoke breathlessness in asthma and COPD.

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Related in: MedlinePlus

Number of bronchoalveolar cells obtained by lung lavage at various points after inoculation of mice with saline (open bars) or C. pneumoniae (black bars). A: Day 2; B: Day 7; C: Day 14, D: Day 21. (*p < 0.05; **p < 0.005; ***p < 0.0001, n = 7–8).
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Figure 2: Number of bronchoalveolar cells obtained by lung lavage at various points after inoculation of mice with saline (open bars) or C. pneumoniae (black bars). A: Day 2; B: Day 7; C: Day 14, D: Day 21. (*p < 0.05; **p < 0.005; ***p < 0.0001, n = 7–8).

Mentions: Two days after the inoculation there was no difference between the experimental groups with respect to total cell numbers, however, there was a slight but significant increase in the number of neutrophils in the C. pneumoniae-group (Fig 2A). There was a prominent inflammation on day 7 and all the different cell types were increased in the C. pneumoniae-group (Fig 2B). The inflammation was slightly less 14 days after infection but still a significant increase in macrophages and neutrophils was observed in the C. pneumoniae-group (Fig. 2C). Comparable results were obtained on day 21, however now there was a significant increase in the number of lymphocytes and the increase in neutrophils was comparable with day 2 (Fig 2A &2D).


Chlamydophila pneumoniae induces a sustained airway hyperresponsiveness and inflammation in mice.

Blasi F, Aliberti S, Allegra L, Piatti G, Tarsia P, Ossewaarde JM, Verweij V, Nijkamp FP, Folkerts G - Respir. Res. (2007)

Number of bronchoalveolar cells obtained by lung lavage at various points after inoculation of mice with saline (open bars) or C. pneumoniae (black bars). A: Day 2; B: Day 7; C: Day 14, D: Day 21. (*p < 0.05; **p < 0.005; ***p < 0.0001, n = 7–8).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2194694&req=5

Figure 2: Number of bronchoalveolar cells obtained by lung lavage at various points after inoculation of mice with saline (open bars) or C. pneumoniae (black bars). A: Day 2; B: Day 7; C: Day 14, D: Day 21. (*p < 0.05; **p < 0.005; ***p < 0.0001, n = 7–8).
Mentions: Two days after the inoculation there was no difference between the experimental groups with respect to total cell numbers, however, there was a slight but significant increase in the number of neutrophils in the C. pneumoniae-group (Fig 2A). There was a prominent inflammation on day 7 and all the different cell types were increased in the C. pneumoniae-group (Fig 2B). The inflammation was slightly less 14 days after infection but still a significant increase in macrophages and neutrophils was observed in the C. pneumoniae-group (Fig. 2C). Comparable results were obtained on day 21, however now there was a significant increase in the number of lymphocytes and the increase in neutrophils was comparable with day 2 (Fig 2A &2D).

Bottom Line: From day 7 to 21 epithelial damage and secretory cell hypertrophy was observed.It is suggested that, the inflammatory cells/mediators, the epithelial damage and secretory cell hypertrophy contribute to initiation of airway hyperresponsiveness.This has clinical implications, since additional changes in airway responsiveness and inflammation-status induced by this bacterium may worsen and/or provoke breathlessness in asthma and COPD.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Respiratory Diseases, University of Milan, IRCCS Ospedale Maggiore Fondazione Policlinico-Mangiagalli-Regina Elena, Milano, Italy. francesco.blasi@unimi.it

ABSTRACT

Background: It has been reported that Chlamydophila (C.) pneumoniae is involved in the initiation and promotion of asthma and chronic obstructive pulmonary diseases (COPD). Surprisingly, the effect of C. pneumoniae on airway function has never been investigated.

Methods: In this study, mice were inoculated intranasally with C. pneumoniae (strain AR39) on day 0 and experiments were performed on day 2, 7, 14 and 21.

Results: We found that from day 7, C. pneumoniae infection causes both a sustained airway hyperresponsiveness and an inflammation. Interferon-gamma (IFN-gamma) and macrophage inflammatory chemokine-2 (MIP-2) levels in bronchoalveolar lavage (BAL)-fluid were increased on all experimental days with exception of day 7 where MIP-2 concentrations dropped to control levels. In contrast, tumor necrosis factor-alpha (TNF-alpha) levels were only increased on day 7. From day 7 to 21 epithelial damage and secretory cell hypertrophy was observed. It is suggested that, the inflammatory cells/mediators, the epithelial damage and secretory cell hypertrophy contribute to initiation of airway hyperresponsiveness.

Conclusion: Our study demonstrates for the first time that C. pneumoniae infection can modify bronchial responsiveness. This has clinical implications, since additional changes in airway responsiveness and inflammation-status induced by this bacterium may worsen and/or provoke breathlessness in asthma and COPD.

Show MeSH
Related in: MedlinePlus