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Cigarette smoke worsens lung inflammation and impairs resolution of influenza infection in mice.

Gualano RC, Hansen MJ, Vlahos R, Jones JE, Park-Jones RA, Deliyannis G, Turner SJ, Duca KA, Anderson GP - Respir. Res. (2008)

Bottom Line: Cigarette smoke has both pro-inflammatory and immunosuppressive effects.Smoke induced inflammation does not protect against influenza infection.In most respects, smoke exposure worsened the host response to influenza.This animal model may be useful in studying how smoke worsens respiratory viral infections.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Pharmacology, The University of Melbourne, Parkville 3010, Victoria, Australia. rgualano@unimelb.edu.au

ABSTRACT

Background: Cigarette smoke has both pro-inflammatory and immunosuppressive effects. Both active and passive cigarette smoke exposure are linked to an increased incidence and severity of respiratory virus infections, but underlying mechanisms are not well defined. We hypothesized, based on prior gene expression profiling studies, that upregulation of pro-inflammatory mediators by short term smoke exposure would be protective against a subsequent influenza infection.

Methods: BALB/c mice were subjected to whole body smoke exposure with 9 cigarettes/day for 4 days. Mice were then infected with influenza A (H3N1, Mem71 strain), and analyzed 3 and 10 days later (d3, d10). These time points are the peak and resolution (respectively) of influenza infection.

Results: Inflammatory cell influx into the bronchoalveolar lavage (BALF), inflammatory mediators, proteases, histopathology, viral titres and T lymphocyte profiles were analyzed. Compared to smoke or influenza alone, mice exposed to smoke and then influenza had more macrophages, neutrophils and total lymphocytes in BALF at d3, more macrophages in BALF at d10, lower net gelatinase activity and increased activity of tissue inhibitor of metalloprotease-1 in BALF at d3, altered profiles of key cytokines and CD4+ and CD8+ T lymphocytes, worse lung pathology and more virus-specific, activated CD8+ T lymphocytes in BALF. Mice smoke exposed before influenza infection had close to 10-fold higher lung virus titres at d3 than influenza alone mice, although all mice had cleared virus by d10, regardless of smoke exposure. Smoke exposure caused temporary weight loss and when smoking ceased after viral infection, smoke and influenza mice regained significantly less weight than smoke alone mice.

Conclusion: Smoke induced inflammation does not protect against influenza infection.In most respects, smoke exposure worsened the host response to influenza. This animal model may be useful in studying how smoke worsens respiratory viral infections.

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Related in: MedlinePlus

Quantitation of relative mRNA units of inflammatory mediators in mouse lung. ■ = influenza alone mice, ▲ = smoke alone and - ◆ - = smoke and influenza mice. Tissue pieces of equivalent size from lungs of the 4 mice in each treatment group were pooled prior to RNA extraction, and the cDNA was used in triplicate reactions. Fold changes are expressed relative to mRNA levels in lungs of no treatment mice.
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Figure 9: Quantitation of relative mRNA units of inflammatory mediators in mouse lung. ■ = influenza alone mice, ▲ = smoke alone and - ◆ - = smoke and influenza mice. Tissue pieces of equivalent size from lungs of the 4 mice in each treatment group were pooled prior to RNA extraction, and the cDNA was used in triplicate reactions. Fold changes are expressed relative to mRNA levels in lungs of no treatment mice.

Mentions: ELISA was used to quantitate protein levels of inflammatory mediators in BALF, and/or real time PCR was used to quantitate mRNA levels of inflammatory mediators in lung (Figures 8 &9). Smoke exposure (without viral infection) was generally associated with higher protein levels of cytokines (e.g. TNF-α, MIP-2, GM-CSF, IFN-γ) in BALF than in no-smoke mice, especially at d10 (Figure 8a–d). We have previously shown that TNF-α mRNA in peripheral fat of smoke exposed mice was unchanged, suggesting that effects of smoke are largely confined to the lung [16]. Influenza increased d3 protein levels of the neutrophil chemoattractant MIP-2 (Figure 8b) and MCP-1 (Figure 8e), more so with prior smoke exposure. Influenza infection alone did not increase other cytokines in BALF. IL-4 protein was undetectable in any sample (data not shown).


Cigarette smoke worsens lung inflammation and impairs resolution of influenza infection in mice.

Gualano RC, Hansen MJ, Vlahos R, Jones JE, Park-Jones RA, Deliyannis G, Turner SJ, Duca KA, Anderson GP - Respir. Res. (2008)

Quantitation of relative mRNA units of inflammatory mediators in mouse lung. ■ = influenza alone mice, ▲ = smoke alone and - ◆ - = smoke and influenza mice. Tissue pieces of equivalent size from lungs of the 4 mice in each treatment group were pooled prior to RNA extraction, and the cDNA was used in triplicate reactions. Fold changes are expressed relative to mRNA levels in lungs of no treatment mice.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2483272&req=5

Figure 9: Quantitation of relative mRNA units of inflammatory mediators in mouse lung. ■ = influenza alone mice, ▲ = smoke alone and - ◆ - = smoke and influenza mice. Tissue pieces of equivalent size from lungs of the 4 mice in each treatment group were pooled prior to RNA extraction, and the cDNA was used in triplicate reactions. Fold changes are expressed relative to mRNA levels in lungs of no treatment mice.
Mentions: ELISA was used to quantitate protein levels of inflammatory mediators in BALF, and/or real time PCR was used to quantitate mRNA levels of inflammatory mediators in lung (Figures 8 &9). Smoke exposure (without viral infection) was generally associated with higher protein levels of cytokines (e.g. TNF-α, MIP-2, GM-CSF, IFN-γ) in BALF than in no-smoke mice, especially at d10 (Figure 8a–d). We have previously shown that TNF-α mRNA in peripheral fat of smoke exposed mice was unchanged, suggesting that effects of smoke are largely confined to the lung [16]. Influenza increased d3 protein levels of the neutrophil chemoattractant MIP-2 (Figure 8b) and MCP-1 (Figure 8e), more so with prior smoke exposure. Influenza infection alone did not increase other cytokines in BALF. IL-4 protein was undetectable in any sample (data not shown).

Bottom Line: Cigarette smoke has both pro-inflammatory and immunosuppressive effects.Smoke induced inflammation does not protect against influenza infection.In most respects, smoke exposure worsened the host response to influenza.This animal model may be useful in studying how smoke worsens respiratory viral infections.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Pharmacology, The University of Melbourne, Parkville 3010, Victoria, Australia. rgualano@unimelb.edu.au

ABSTRACT

Background: Cigarette smoke has both pro-inflammatory and immunosuppressive effects. Both active and passive cigarette smoke exposure are linked to an increased incidence and severity of respiratory virus infections, but underlying mechanisms are not well defined. We hypothesized, based on prior gene expression profiling studies, that upregulation of pro-inflammatory mediators by short term smoke exposure would be protective against a subsequent influenza infection.

Methods: BALB/c mice were subjected to whole body smoke exposure with 9 cigarettes/day for 4 days. Mice were then infected with influenza A (H3N1, Mem71 strain), and analyzed 3 and 10 days later (d3, d10). These time points are the peak and resolution (respectively) of influenza infection.

Results: Inflammatory cell influx into the bronchoalveolar lavage (BALF), inflammatory mediators, proteases, histopathology, viral titres and T lymphocyte profiles were analyzed. Compared to smoke or influenza alone, mice exposed to smoke and then influenza had more macrophages, neutrophils and total lymphocytes in BALF at d3, more macrophages in BALF at d10, lower net gelatinase activity and increased activity of tissue inhibitor of metalloprotease-1 in BALF at d3, altered profiles of key cytokines and CD4+ and CD8+ T lymphocytes, worse lung pathology and more virus-specific, activated CD8+ T lymphocytes in BALF. Mice smoke exposed before influenza infection had close to 10-fold higher lung virus titres at d3 than influenza alone mice, although all mice had cleared virus by d10, regardless of smoke exposure. Smoke exposure caused temporary weight loss and when smoking ceased after viral infection, smoke and influenza mice regained significantly less weight than smoke alone mice.

Conclusion: Smoke induced inflammation does not protect against influenza infection.In most respects, smoke exposure worsened the host response to influenza. This animal model may be useful in studying how smoke worsens respiratory viral infections.

Show MeSH
Related in: MedlinePlus