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Combined exposure to cigarette smoke and nontypeable Haemophilus influenzae drives development of a COPD phenotype in mice.

Ganesan S, Comstock AT, Kinker B, Mancuso P, Beck JM, Sajjan US - Respir. Res. (2014)

Bottom Line: CS/HK-NTHi-exposed mice also expressed increased levels of mucin genes and cytokines compared to mice in other groups.CS/HK-NTHi-exposed mice infected with RV demonstrated increased viral persistence, sustained neutrophilia, and further increments in mucin gene and chemokine expression compared to other groups.These findings indicate that in addition to CS, bacteria may also contribute to development of COPD, particularly changes in airways.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Pediatrics and Communicable Diseases, University of Michigan, 1150 W, Medical Center Dr,, Ann Arbor, MI 48109-5688, USA. usajjan@umich.edu.

ABSTRACT

Background: Cigarette smoke (CS) is the major etiologic factor of chronic obstructive pulmonary disease (COPD). CS-exposed mice develop emphysema and mild pulmonary inflammation but no airway obstruction, which is also a prominent feature of COPD. Therefore, CS may interact with other factors, particularly respiratory infections, in the pathogenesis of airway remodeling in COPD.

Methods: C57BL/6 mice were exposed to CS for 2 h a day, 5 days a week for 8 weeks. Mice were also exposed to heat-killed non-typeable H. influenzae (HK-NTHi) on days 7 and 21. One day after the last exposure to CS, mice were sacrificed and lung inflammation and mechanics, emphysematous changes, and goblet cell metaplasia were assessed. Mice exposed to CS or HK-NTHi alone or room air served as controls. To determine the susceptibility to viral infections, we also challenged these mice with rhinovirus (RV).

Results: Unlike mice exposed to CS or HK-NTHi alone, animals exposed to CS/HK-NTHi developed emphysema, lung inflammation and goblet cell metaplasia in both large and small airways. CS/HK-NTHi-exposed mice also expressed increased levels of mucin genes and cytokines compared to mice in other groups. CS/HK-NTHi-exposed mice infected with RV demonstrated increased viral persistence, sustained neutrophilia, and further increments in mucin gene and chemokine expression compared to other groups.

Conclusions: These findings indicate that in addition to CS, bacteria may also contribute to development of COPD, particularly changes in airways. Mice exposed to CS/HK-NTHi are also more susceptible to subsequent viral infection than mice exposed to either CS or HK-NTHi alone.

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Related in: MedlinePlus

Lung inflammation. Bronchoalveolar lavage from RA, CS, HK-NTHi or CS/HK-NTHi mice was centrifuged and the pellet was used to determine total (A) and differential cell (B and C) counts. Supernatant was used to determine levels of IL-1β (D), TNF-α (E), MCP-1 (F) and KC (G) by ELISA. Data in A to C and D to G respectively represent median with range and mean ± SD calculated from 5–6 mice per group (* different from RA-exposed mice, p ≤ 0.05, ANOVA on ranks in A to C and ANOVA in D to G; # different from CS-exposed mice, p ≤ 0.05, ANOVA on ranks in A to C and ANOVA in D to G; † different from HK-NTHi-exposed mice, ANOVA on ranks in A to C and ANOVA in D to G).
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Figure 4: Lung inflammation. Bronchoalveolar lavage from RA, CS, HK-NTHi or CS/HK-NTHi mice was centrifuged and the pellet was used to determine total (A) and differential cell (B and C) counts. Supernatant was used to determine levels of IL-1β (D), TNF-α (E), MCP-1 (F) and KC (G) by ELISA. Data in A to C and D to G respectively represent median with range and mean ± SD calculated from 5–6 mice per group (* different from RA-exposed mice, p ≤ 0.05, ANOVA on ranks in A to C and ANOVA in D to G; # different from CS-exposed mice, p ≤ 0.05, ANOVA on ranks in A to C and ANOVA in D to G; † different from HK-NTHi-exposed mice, ANOVA on ranks in A to C and ANOVA in D to G).

Mentions: To assess lung inflammation, we performed total and differential cell counts and quantified levels of IL-1β, TNF-α, KC and MCP-1 by ELISA. Compared to mice exposed to RA or CS, mice in HK-NTHi and CS/HK-NTHi groups showed a significantly higher numbers of total cells (RA vs HK-NTHi, p = 0.043; CS vs HK-NTHi, p = 0.048; RA vs CS/HK-NTHi p = 0.013; CS vs CS/HK-NTHi, p = 0.025) with the largest increase observed in the CS/HK-NTHi group (HK-NTHi vs CS/HK-NTHi, p = 0.0103) (Figure 4A). Both macrophages (Figure 4B) and lymphocytes were higher (Figure 4C) in the airways of CS/HK-NTHi than in RA-exposed mice (p = 0.027 and p = 0.031 respectively). Only the number of lymphocytes increased significantly in CS, HK-NTHi-exposed mice compared to RA-exposed mice (p = 0.049 and p = 0.043 respectively). There were no significant differences in numbers of neutrophils among the groups (data not shown). We then examined the levels of cytokines in the lavage fluid (Figure 4D to4G). Compared to mice exposed to RA, mice in all other groups showed more IL-1β (RA vs CS, p = 0.043; RA vs HK-NTHi, p = 0.042; RA vs CS/HK-NTHi, p = 0.037) and KC levels (RA vs CS, p = 0.010; RA vs HK-NTHi, p = 0.007; RA vs CS/HK-NTHi, p = 0.023). Mice in HK-NTHi or CS/HK-NTHi groups, but not in the CS group showed higher levels of MCP-1 (RA vs HK-NTHi, p = 0.042; RA vs CS/HK-NTHi, p = 0.001) and TNF-α (RA vs HK-NTHi, p = 0.049; RA vs CS/HK-NTHi, p = 0.02) than the RA group. However, mice in the CS/HK-NTHi group showed the highest increases in the levels of all the cytokines measured.


Combined exposure to cigarette smoke and nontypeable Haemophilus influenzae drives development of a COPD phenotype in mice.

Ganesan S, Comstock AT, Kinker B, Mancuso P, Beck JM, Sajjan US - Respir. Res. (2014)

Lung inflammation. Bronchoalveolar lavage from RA, CS, HK-NTHi or CS/HK-NTHi mice was centrifuged and the pellet was used to determine total (A) and differential cell (B and C) counts. Supernatant was used to determine levels of IL-1β (D), TNF-α (E), MCP-1 (F) and KC (G) by ELISA. Data in A to C and D to G respectively represent median with range and mean ± SD calculated from 5–6 mice per group (* different from RA-exposed mice, p ≤ 0.05, ANOVA on ranks in A to C and ANOVA in D to G; # different from CS-exposed mice, p ≤ 0.05, ANOVA on ranks in A to C and ANOVA in D to G; † different from HK-NTHi-exposed mice, ANOVA on ranks in A to C and ANOVA in D to G).
© Copyright Policy - open-access
Related In: Results  -  Collection

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Figure 4: Lung inflammation. Bronchoalveolar lavage from RA, CS, HK-NTHi or CS/HK-NTHi mice was centrifuged and the pellet was used to determine total (A) and differential cell (B and C) counts. Supernatant was used to determine levels of IL-1β (D), TNF-α (E), MCP-1 (F) and KC (G) by ELISA. Data in A to C and D to G respectively represent median with range and mean ± SD calculated from 5–6 mice per group (* different from RA-exposed mice, p ≤ 0.05, ANOVA on ranks in A to C and ANOVA in D to G; # different from CS-exposed mice, p ≤ 0.05, ANOVA on ranks in A to C and ANOVA in D to G; † different from HK-NTHi-exposed mice, ANOVA on ranks in A to C and ANOVA in D to G).
Mentions: To assess lung inflammation, we performed total and differential cell counts and quantified levels of IL-1β, TNF-α, KC and MCP-1 by ELISA. Compared to mice exposed to RA or CS, mice in HK-NTHi and CS/HK-NTHi groups showed a significantly higher numbers of total cells (RA vs HK-NTHi, p = 0.043; CS vs HK-NTHi, p = 0.048; RA vs CS/HK-NTHi p = 0.013; CS vs CS/HK-NTHi, p = 0.025) with the largest increase observed in the CS/HK-NTHi group (HK-NTHi vs CS/HK-NTHi, p = 0.0103) (Figure 4A). Both macrophages (Figure 4B) and lymphocytes were higher (Figure 4C) in the airways of CS/HK-NTHi than in RA-exposed mice (p = 0.027 and p = 0.031 respectively). Only the number of lymphocytes increased significantly in CS, HK-NTHi-exposed mice compared to RA-exposed mice (p = 0.049 and p = 0.043 respectively). There were no significant differences in numbers of neutrophils among the groups (data not shown). We then examined the levels of cytokines in the lavage fluid (Figure 4D to4G). Compared to mice exposed to RA, mice in all other groups showed more IL-1β (RA vs CS, p = 0.043; RA vs HK-NTHi, p = 0.042; RA vs CS/HK-NTHi, p = 0.037) and KC levels (RA vs CS, p = 0.010; RA vs HK-NTHi, p = 0.007; RA vs CS/HK-NTHi, p = 0.023). Mice in HK-NTHi or CS/HK-NTHi groups, but not in the CS group showed higher levels of MCP-1 (RA vs HK-NTHi, p = 0.042; RA vs CS/HK-NTHi, p = 0.001) and TNF-α (RA vs HK-NTHi, p = 0.049; RA vs CS/HK-NTHi, p = 0.02) than the RA group. However, mice in the CS/HK-NTHi group showed the highest increases in the levels of all the cytokines measured.

Bottom Line: CS/HK-NTHi-exposed mice also expressed increased levels of mucin genes and cytokines compared to mice in other groups.CS/HK-NTHi-exposed mice infected with RV demonstrated increased viral persistence, sustained neutrophilia, and further increments in mucin gene and chemokine expression compared to other groups.These findings indicate that in addition to CS, bacteria may also contribute to development of COPD, particularly changes in airways.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Pediatrics and Communicable Diseases, University of Michigan, 1150 W, Medical Center Dr,, Ann Arbor, MI 48109-5688, USA. usajjan@umich.edu.

ABSTRACT

Background: Cigarette smoke (CS) is the major etiologic factor of chronic obstructive pulmonary disease (COPD). CS-exposed mice develop emphysema and mild pulmonary inflammation but no airway obstruction, which is also a prominent feature of COPD. Therefore, CS may interact with other factors, particularly respiratory infections, in the pathogenesis of airway remodeling in COPD.

Methods: C57BL/6 mice were exposed to CS for 2 h a day, 5 days a week for 8 weeks. Mice were also exposed to heat-killed non-typeable H. influenzae (HK-NTHi) on days 7 and 21. One day after the last exposure to CS, mice were sacrificed and lung inflammation and mechanics, emphysematous changes, and goblet cell metaplasia were assessed. Mice exposed to CS or HK-NTHi alone or room air served as controls. To determine the susceptibility to viral infections, we also challenged these mice with rhinovirus (RV).

Results: Unlike mice exposed to CS or HK-NTHi alone, animals exposed to CS/HK-NTHi developed emphysema, lung inflammation and goblet cell metaplasia in both large and small airways. CS/HK-NTHi-exposed mice also expressed increased levels of mucin genes and cytokines compared to mice in other groups. CS/HK-NTHi-exposed mice infected with RV demonstrated increased viral persistence, sustained neutrophilia, and further increments in mucin gene and chemokine expression compared to other groups.

Conclusions: These findings indicate that in addition to CS, bacteria may also contribute to development of COPD, particularly changes in airways. Mice exposed to CS/HK-NTHi are also more susceptible to subsequent viral infection than mice exposed to either CS or HK-NTHi alone.

Show MeSH
Related in: MedlinePlus