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American Journal of Respiratory and Critical Care Medicine Vol 167. pp. 764-770, (2003)
© 2003 American Thoracic Society

Original Article

Impaired Pulmonary Inflammatory Responses Are a Prominent Feature of Streptococcal Pneumonia in Mice with Experimental Emphysema

Sumito Inoue, Hidenori Nakamura, Kazuhisa Otake, Hiroshi Saito, Kyoko Terashita, Jun Sato, Hiroaki Takeda and Hitonobu Tomoike

First Department of Internal Medicine, Yamagata University School of Medicine, Yamagata; Respiratory Medicine, Sei-rei Hamamatsu General Hospital, Shizuoka, Japan

Correspondence and requests for reprints should be addressed to Sumito Inoue, M.D., First Department of Internal Medicine, Yamagata University School of Medicine, 2-2-2, Iida-Nishi, Yamagata 990-9585, Japan. E-mail: BYC04033{at}nifty.ne.jp


   ABSTRACT
TOP
 ABSTRACT
METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
Little is known about why patients with chronic obstructive pulmonary disease are susceptible to bacterial infections. Using an animal model of pulmonary emphysema, we investigated the inflammatory responses to bacterial infection. After intratracheal infection with Streptococcus pneumoniae (103–107 cfu/mouse), the control mice did not die. However, the mice with emphysema died in a dose-dependent manner. Bronchoalveolar lavage fluid, examined 24 hours after infection showed that the numbers of total cells and neutrophils, in addition to murine tumor necrosis factor-{alpha} and macrophage inflammatory protein-2 concentrations, were significantly less in the mice with emphysema compared with the control mice. Histopathologic findings revealed that the alveoli were filled with inflammatory cells and exudate in the control mice but not in the mice with emphysema. Seventy-two hours after infection, serum cytokine levels were significantly higher in the mice with emphysema, and significant numbers of S. pneumoniae were detected in both the whole lung tissues and the blood of mice with emphysema. These findings suggest that the inflammatory response in mice with emphysema was impaired at the site of bacterial infection despite the bacteremia, which accelerated severe systemic inflammatory responses. Accordingly, intra-alveolar but not systemic immune responses to bacterial infection were impaired in the presence of experimental emphysema.

Key Words: chronic obstructive pulmonary disease • bacterial infection • cytokine • Streptococcus pneumoniae • bacteremia

Chronic obstructive pulmonary disease (COPD) is a common disease, characterized by various levels of airflow obstruction, and it is one of the major medical problems in developed countries, including Japan (1–6). The natural history of COPD is associated with frequent respiratory tract infections, which result in exacerbation, severe respiratory failure, and death (7–9). Recurrent infection of the respiratory tract leads to significant problems for patients with COPD not only by way of medical complications but also by way of costs of care (4, 5, 10–14).

COPD is generally considered to be an important predisposing condition for pneumonia, although conclusive or definitive evidence showing that the risk of pneumonia for patients with COPD is higher than for the general population remains to be confirmed (15–17). Specifically, little is known about the precise mechanisms of how or why patients with COPD are susceptible to bacterial infection. In addition, there have been few studies about bacterial infection of the respiratory tracts in animal models of COPD. The purpose of the present study was to investigate the pathophysiology of the susceptibility to bacterial infection in patients with COPD, using a mouse model of elastase-induced pulmonary emphysema. Because Streptococcus pneumoniae is one of the major bacterial pathogens of respiratory infections in patients with COPD (4, 7, 8, 12, 18), we used it as a pathogen.


   METHODS
TOP
 ABSTRACT
 METHODS
RESULTS
 DISCUSSION
 REFERENCES
 
Animals
Specific pathogen-free male ICR mice, 8 weeks of age, were purchased from Japan Clea Co. (Tokyo, Japan). All experiments using mice in this study were approved by the institutional animal care and use committee.

Preparation of S. pneumoniae
S. pneumoniae Serotype 3 (Otsuka Pharmaceutical Co. Ltd., Tokushima, Japan) is penicillin-sensitive. The minimal inhibitory concentration of penicillin G against the organism was less than or equal to 0.06 µg/ml. S. pneumoniae were incubated at 37°C in tryptic soy broth (DIFCO, Detroit, MI) with 10% fetal bovine serum. The bacterial number was estimated by measuring the optical density at 660 nm with a spectrophotometer. The challenged bacterial number was determined by counting by the number of colonies on the blood agar plates (19–23).

An Emphysematous Model
To produce pulmonary emphysema, mice were anesthetized with an intraperitoneal injection of thiopental sodium (150 mg/kg body weight), and the trachea was intubated with a 22-gauge cannula. Porcine pancreatic elastase (PPE) (Calbiochem-Novabiochem Co., USA) in phosphate-buffered salt solution (PBS) was intratracheally administered via a cannula in doses of 6 (n = 5), 9 (n = 5), 12 (n = 5) unit/50 µl. Control mice (n = 5) were treated similarly but with 50 µl of PBS (24–29).

Streptococcal Infection
Three weeks after 12 U of elastase treatment, suspensions containing 103 to 107 cfu of S. pneumoniae/100 µl broth were intratracheally administered to both control (n = 52) and mice with emphysema (n = 63) under conditions of intraperitoneal anesthesia.

Preparation of Serum
At 24 and 72 hours after inoculation, whole blood was obtained by direct puncture of the right ventricular cavity in mice, which had been deeply anesthetized with excess intraperitoneal thiopental sodium (450 mg/kg body weight). Individual sera were separated from the clotted blood by centrifugation and stored at -80°C until the assays were performed.

Bronchoalveolar Lavage
After blood was drawn by direct puncture of the right ventricle, bronchoalveolar lavage (BAL) was performed. In brief, a 22-gauge cannula was wedged into the trachea. Three milliliters of PBS was infused and recovered via a cannula. These manipulations were performed gently to avoid artificial lung injury. Cytologic preparations were made using centrifugation (Cytospin 2; Shandon, Pittsburgh, PA) and were stained with modified May-Giemsa stain (Diff Quick; American Science Products, McGaw Park, IL). Differential cell counts were performed on 200 cells per sample. Cells were removed from BAL fluids (BALF) by centrifugation at 200 x g for 10 minutes, and supernatants of BALF were stored at -80°C until evaluation.

Biochemical Analysis of BALF and Serum
Murine tumor necrosis factor-{alpha} (TNF-{alpha}), KC (cytokine-induced neutrophil chemoattractant, CXCL1), and macrophage inflammatory protein-2 (MIP-2) in both BALF and serum were measured by ELISA (Quantikine; R&D Systems, Minneapolis, MN) because these cytokines are known to act as key molecules in inflammatory responses in bacterial infections (30–37).

Histologic Analysis
For morphologic examinations, both lungs were inflated under constant positive pressure at 25 cm water pressure with 10% buffered formaldehyde and were then perfuse-fixed. The fixed lungs were embedded in paraffin, stained with hematoxylin and eosin, and examined using a microscope (BX50F4; Olympus, Tokyo, Japan) (38). The severity of structural alternations in the emphysematous model was determined morphometrically using the mean linear intercept of the airspaces. This is one of the more common parameters for determining emphysema in laboratory animals and humans (25, 28, 39, 40). We evaluated 10 randomly selected fields per lobe or lung part. The whole lung mean linear intercept value was derived as a mean of the left and right lung mean linear intercept values.

Bacteriologic Examination
The severity of bacterial infection in the lung tissue and blood were quantitatively evaluated as bacterial colony numbers after infection. Namely, lungs were homogenized in 1 ml of PBS, and the homogenates were serially diluted 10-fold with PBS. One hundred microliters of the diluents of lung homogenates or 10 µl of blood were spread on blood agar plates. The plates were incubated at 37°C with 5% carbon dioxide for 18 hours (22, 41). The bacterial numbers were determined by counting the colonies on the plates, and expressed as cfus.

Statistical Analysis
All values are expressed as means ± SEM. Two-factor functional analysis of variance was performed to assess differences between the groups. The differences between the groups or between periods were further compared using Tukey-Kramer tests with an adjustment of the p values (p < 0.05). A p value of less than 0.05 was considered statistically significant.


   RESULTS
TOP
 ABSTRACT
 METHODS
 RESULTS
DISCUSSION
 REFERENCES
 
Severity of Experimental Pulmonary Emphysema
After intratracheal elastase instillations, we confirmed histologically the dose-dependent emphysematous changes throughout the lung (data not shown). Morphometric analyses demonstrated that the mean linear intercept in lungs from elastase-treated mice were significantly increased in a dose-dependent manner (control mice; 33.90 ± 0.68 µm, PPE 6 U; 41.98 ± 1.66 µm, PPE 9 U; 50.31 ± 1.06 µm, PPE 12 U; 67.21 ± 2.00 µm, p < 0.05, control vs. PPE 6 U, 9 U, and 12 U, PPE 6 U vs. PPE 9 U, and 12 U, PPE 9 U vs. PPE 12 U). In the following experiments, we used 12 U of PPE to produce experimental emphysema.

Survival After Infection
Figure 1 illustrates the survival curves obtained from four groups of mice with different doses of S. pneumoniae inoculation. The control mice did not die after a challenge of S. pneumoniae up to a dose of 4.9 x 107 cfu/mouse. Mice with emphysema became emaciated and died in a dose-dependent manner within several days. Mice with emphysema without infection survived throughout the observation period.



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  		Figure 1. Survival rate in control and mice with emphysema. Control mice did not die after challenge with 4.9 x 107 cfu/mouse of S. pneumoniae. Mice with emphysema died after challenge with 3.6 x 103 {bsim} 4.9 x 107 cfu/mouse of S. pneumoniae in a challenged bacterial dose-dependent fashion.

 
BALF Analysis
Cell numbers and differential cell counts.
Cell compositions of BALF are summarized in Figure 2 . There was no significant difference in the volume of the lavage fluid retrieved between the two groups of mice (control mice 2.46 ± 0.64 ml vs. mice with emphysema 2.26 ± 0.55 ml; not significant). Before infection, there were no significant differences in total cell counts and cellular profiles between the control and mice with emphysema. At 24 hours after infection, total cell counts, especially neutrophils, were significantly increased in the control mice. The number of total cells and neutrophils in BALF from the mice with emphysema were significantly lower than those of the control mice. Seventy-two hours after infection, there were no significant differences in cellular counts between the control and mice with emphysema.



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  		Figure 2. Total cell counts and differential cell counts in BALF. Before infection, there were no significant differences in total cell counts and cellular profiles between control and mice with emphysema. At 22 hours after infection, total cell counts, especially neutrophils, were significantly increased in control mice (p < 0.05). The numbers of total cells and neutrophils in BALF from mice with emphysema were significantly lower than those of control mice. A total of 4.9 x 107 cfu/mouse of S. pneumoniae were challenged. #p value less than 0.05 compared with the neutrophil counts in control mice at 24 hours. *p value less than 0.05 compared with the total cell counts in control mice at 24 hours.

 
Cytokine levels in BALF.
Time course of the levels of TNF-{alpha}, KC, and MIP-2 in BALF after infection are shown in Figures 3A–3C . Before infection, the levels of these cytokines in BALF were very low in both the control and mice with emphysema. At 24 hours after infection, TNF-{alpha}, KC, and MIP-2 levels in the control mice were significantly increased, however, the extent of TNF-{alpha} and MIP-2 increases in the mice with emphysema were significantly lower than in the control mice.



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  		Figure 3. Time course of TNF-{alpha} (A), KC (B), and MIP-2 (C) levels in BALF from control and mice with emphysema. TNF-{alpha} and MIP-2 levels in mice with emphysema were significantly lower than in control mice 24 hours after infection. Seventy two hours after infection, TNF-{alpha} levels in control and mice with emphysema, and KC and MIP-2 levels in control mice significantly decreased compared with those at 24 hours after infection. A total of 4.9 x 107 cfu/mouse of S. pneumoniae were challenged. {dagger} p value less than 0.05. *p value less than 0.05 compared with control mice. MIP-2, macrophage inflammatory protein-2; TNF-{alpha}, tumor necrosis factor-{alpha}.

 
At 72 hours, TNF-{alpha}, KC, and MIP-2 levels in BALF decreased from the 24-hour level in the control mice. In the mice with emphysema, the cytokines levels decreased except for KC.

Histologic Changes After Infection
Representative microscopic findings of the lungs in the control and mice with emphysema 24 and 72 hours after infection are shown in Figure 4 . In the control mice, the alveoli were filled with inflammatory cells, especially neutrophils and exudate, 24 hours after infection (Figure 4A), and the inflammatory cells and exudate disappeared from the alveolar spaces 72 hours after infection (Figure 4B). In the mice with emphysema, inflammatory cell infiltrations in alveolar spaces were less at both 24 and 72 hours after infection (Figures 4C and 4D). Alveolar wall thickening with eosinophilic materials and capillary congestion with red blood cells were evident in the mice with emphysema at 72 hours.



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  		Figure 4. Histologic findings of the lung tissue sections (hematoxylin and eosin stain, x200). A total of 4.9 x 107 cfu/mouse of S. pneumoniae were challenged. (A) Control mice, 24 hours after infection. The alveoli were filled with inflammatory cells, especially neutrophils and exudate. (B) Control mice, 72 hours after infection. Inflammatory cells and exudate disappeared from the alveolar spaces. (C) Mice with emphysema, 24 hours after infection. There were less inflammatory changes in alveolar spaces compared with control mice. Inflammatory cells infiltrated normal-looking alveoli rather than emphysematous alveoli. (D) Mice with emphysema, 72 hours after infection. Alveolar wall thickening with eosinophilic materials and capillary congestion with red blood cells is evident.

 
Systemic Inflammatory Changes
Before infection, there was no significant difference in white blood cell (WBC) counts in punctured blood between the control and mice with emphysema (Figure 5) . At 24 hours after infection, WBC counts in both the control and mice with emphysema were significantly higher than before infection. At 72 hours, WBC counts decreased in both the control and mice with emphysema. Specifically, WBC counts in mice with emphysema tended to decrease after infection.



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  		Figure 5. Time course of WBC counts in blood from control and mice with emphysema. At 24 hours after infection, WBC counts in control and mice with emphysema significantly increased compared with WBC counts before infection. At 72 hours, WBC counts decreased in both control and mice with emphysema. Specifically, WBC counts in mice with emphysema tended to decrease below the levels before infection. A total of 1.76 x 105 cfu/mouse of S. pneumoniae were challenged. {dagger}p value less than 0.05. WBC, white blood cell.

 
Serum TNF-{alpha}, KC, and MIP-2 levels are summarized in Figures 6A–6C . Before infection, there were no significant differences in TNF-{alpha}, KC, and MIP-2 levels between the control and mice with emphysema. After infection, serum cytokine levels increased in both groups of mice 72 hours after infection. Increased levels of serum cytokines were significantly higher in mice with emphysema compared with the control mice.



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  		Figure 6. Time course of TNF-{alpha} (A), KC (B), and MIP-2 (C) levels in serum from control and mice with emphysema. At 24 hours after infection, each cytokine level in mice with emphysema tended to be higher than those in control mice. TNF-{alpha}, KC, and MIP-2 levels 72 hours after infection in mice with emphysema were significantly higher than those in control mice. A total of 4.9 x 107 cfu/mouse of S. pneumoniae were challenged. {dagger}p value less than 0.05. *p value less than 0.05 compared with control mice. MIP-2, macrophage inflammatory protein-2; TNF-{alpha}, tumor necrosis factor-{alpha}.

 
Bacterial Colony Counts in Whole Lung Tissues and Blood
Bacterial colony numbers from lung tissues are shown in Figure 7 . At 24 hours after infection, the bacterial counts in whole lung tissues were not significantly different between the two groups of mice. At 72 hours, the bacterial counts in lung tissues from the control mice decreased. In contrast, the number of bacterial colonies in lung tissues from mice with emphysema markedly increased (control mice 1.71 ± 0.92 x 106 cfu/lung, emphysema 7.58 ± 5.73 x 107 cfu/lung, NS.).



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  		Figure 7. Bacterial counts from total lung tissue after streptococcal infection (log scale). Seventy-two hours after infection, bacterial counts in control mice decreased. In contrast, bacterial colony growth in mice with emphysema markedly increased. A total of 1.76 x 105 cfu/mouse of S. pneumoniae were challenged.

 
Bacterial cultures from punctured blood are summarized in Table 1 . In two to three of the five control mice, blood cultures were positive for S. pneumoniae 24 hours after infection. Quantitatively, the bacterial number had decreased 72 hours after infection in the control mice. In contrast, all mice with emphysema were bacteremic 24 hours after infection, and the numbers of bacteria in blood increased markedly 72 hours after infection.


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  		TABLE 1. Bacterial culture in blood

 

   DISCUSSION
TOP
 ABSTRACT
 METHODS
 RESULTS
 DISCUSSION
REFERENCES
 
In the present study, we demonstrated the unique inflammatory responses to bacterial infection in the lungs of mice with elastase-induced emphysema. Early responses in the lungs after infection, including the infiltration of neutrophils and production of inflammatory cytokines such as TNF-{alpha} or MIP-2, were significantly less in mice with emphysema. These findings are in parallel with the histologic findings. Because inflammatory responses in lungs, such as neutrophil migration and cytokine production, play an important role in host defense in the alveolar space during the acute phase of bacterial infection (30–36, 42), an impaired inflammatory response in the lungs may be one of the most important contributing factors to the susceptibility of infection in mice with experimental emphysema.

Mechanism of the Blunted Inflammatory Response in Lungs of Mice with Emphysema
No clear answer was found to explain why mice with emphysema showed impaired inflammatory responses in lungs. First, the bacteria entering the alveolus are likely to be thrust up against the alveolar wall, where they will become immersed in the epithelial lining fluid. There they would be coated with various nonimmune opsonins and a specific IgG antibody (43, 44). The antibody creates an antigen–antibody reaction that activates a complement sequence resulting in bacterial lysis. A mixture of opsonins adhere to the bacterium and facilitate ingestion by alveolar macrophages. Because the principal function of innate immunity is to rapidly clear inhaled substances to prevent the establishment of an inflammatory process, further studies are needed to clarify whether innate immunity is suppressed in emphysematous lungs.

A second possibility is that alveolar macrophages in emphysematous lungs come into less contact with microbes in the enlarged airspaces in vivo. Experimentally, when a bacterial inoculum is instilled onto the alveolar surface, bacteria remain free for only a short time (30 minutes or so) before they are internalized within a macrophage (43, 45). Once the bacterium is within the macrophage, the macrophage's bactericidal mechanisms destroy the microbe. The lower BALF cytokine levels in the mice with emphysema may be due to the loss of contact with alveolar macrophages and/or to altered function of alveolar macrophages. It is also possible that chemokine production by other airway cells was blunted in the mice with emphysema (46–49).

Third, systemic responses such as serum cytokine concentrations in mice with emphysema were significantly higher than those in the control mice. The present findings suggest that severe systemic inflammatory response in mice with emphysema occurred because of severe bacteremia and that the major site of the inflammatory response moved from the alveolar space to the systemic circulation. These reversed cytokine gradients could impair neutrophil influx into the alveolar spaces after infection in the mice with emphysema. It is also possible that the loss of the capillary bed and damage to the capillary basement membrane by neutrophils elastase may have contributed to the impaired influx of neutrophils. The higher mortality of the mice with emphysema might be due to decreased microbial killing, perhaps because of the modest decrement in neutrophil recruitment, or it may reflect failed containment in the lungs and greater systemic toxicity.

Finally, Mauderly and coworkers studied the influence of pre-existing pulmonary emphysema on the susceptibility of rats to inhaled diesel exhaust and showed that less soot accumulated in the lungs of emphysematous rats than in those of nonemphysematous rats. It has been suggested that emphysematous lung had an unknown function, which accelerated the removal of inhaled dust from alveolar lumens to bronchiole or blood flow, in the emphysematous rats (50). In addition, they demonstrated impaired inflammatory responses to the diesel exhaust in emphysematous rats. The numbers of neutrophils in BALF from emphysematous rats exposed to diesel exhaust were significantly less than those from nonemphysematous control rats. Emphysema prevented the expression of an exhaust-induced increase in lung collagen and reduced the exhaust-induced delay in particle clearance and the exhaust-induced increase in lavage fluid indicators of lung damage. In addition, Gross and deTreville also reported the reduced susceptibility of emphysematous rats to inhaled quartz, which was due to the reduced accumulation of particles in emphysematous lungs (51). Although there are several differences between the present study and the studies by Mauderly and coworkers and Gross and deTreville, this acceleration of removal might be one of the causes in the susceptibility of lethal streptococcal infection in mice with emphysema.

S. pneumoniae is one of the most frequent respiratory pathogens in patients with COPD and patients with community-acquired pneumonia (4, 7, 8, 10, 52, 53). Many experimental studies have been reported about respiratory tract infections using various strains of mice (19, 20, 54–57). Although some strains of mice are susceptible to S. pneumoniae Serotype 19, a penicillin-resistant strain, ICR mice were reported to be resistant to them (19, 56, 57). We demonstrated that control ICR mice were resistant to S. pneumoniae Serotype 3, a penicillin-sensitive strain. Importantly, emphysematous ICR mice died after intratracheal challenge with S. pneumoniae Serotype 3. This is the first study to demonstrate the differences in inflammatory response to, and the lethality of, the streptococcal infection between normal mice and mice with experimental emphysema.

Many animal models of pulmonary emphysema have been reported (24, 29). In the present experiments, we used elastase-induced emphysema in mice because we could produce experimental emphysema reproducibly and clearly. Emphysematous lesions were produced within 3 weeks after elastase instillation, and the severity of emphysematous changes was elastase dose-dependent. This experimental model has been used in other studies to produce emphysema in laboratory rodents (29). In the absence of bacterial infection, there were no significant differences in cells and cytokines in BALF and serum between the control and mice with emphysema. The present mouse model is different from the findings in the lungs of patients with COPD, who generally have chronic inflammation in the alveolar wall and infiltration of neutrophils in the airway (58, 59).

In conclusion, we have shown that mice with pulmonary emphysema are susceptible to S. pneumoniae infection. The mechanism of susceptibility is related to impaired host defense in the lungs during the acute phase of infection. Future studies of the susceptibility of mice with emphysema to pneumococcal pneumonia will be needed to clarify the basic mechanisms.


   Acknowledgments
 
The authors gratefully acknowledge Eiji Tsuchida, Tsunetaka Ito, Choichiro Takahashi, and Reiko Ota of Yamagata University School of Medicine, Yamagata, Japan, and Kazunori Omori, Osamu Mukeda, and Kinue Oguro of Otsuka Pharmaceutical Co. Ltd., for technical assistance during this study. The authors would also like to thank Arjuna Celaya and Daniel Mrozek for assistance with the English.


   FOOTNOTES
 
Supported by grants-in-aid for scientific research (10307016, 11557044) from the Ministry of Education, Science, Sports and Culture, Japan.

Received in original form May 23, 2001; accepted in final form December 2, 2002


   REFERENCES
TOP
 ABSTRACT
 METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 

  1. Murray CJ, Lopez AD. Alternative projections of mortality and disability by cause 1990–2020: global burden of disease study. Lancet 1997;349:1498–1504.[CrossRef][Medline]
  2. Lopez AD, Murray CC. The global burden of disease, 1990–2020. Nat Med 1998;4:1241–1243.[CrossRef][Medline]
  3. Gravil JH, Al-Rawas OA, Cotton MM, Flanigan U, Irwin A, Stevenson RD. Home treatment of exacerbations of chronic obstructive pulmonary disease by an acute respiratory assessment service. Lancet 1998;351:1853–1855.[CrossRef][Medline]
  4. Connors AF Jr, Dawson NV, Thomas C, Harrell FE Jr, Desbiens N, Fulkerson WJ, Kussin P, Bellamy P, Goldman L, Knaus WA. Outcomes following acute exacerbation of severe chronic obstructive lung disease. Am J Respir Crit Care Med 1996;154:959–967.[Abstract]
  5. Saint S, Bent S, Vittinghoff E, Grady D. Antibiotics in chronic obstructive pulmonary disease exacerbations: a meta-analysis. JAMA 1995;273:957–960.[Abstract]
  6. Hurd SS. International efforts directed at attacking the problem of COPD. Chest 2000;117(5 Suppl 2):336S–338S.[Abstract/Free Full Text]
  7. Soler N, Torres A, Ewig S, Gonzalez J, Celis R, El-Ebiary M, Hernandez C, Rodriguez-Roisin R. Bronchial microbial patterns in severe exacerbations of chronic obstructive pulmonary disease (COPD) requiring mechanical ventilation. Am J Respir Crit Care Med 1998;157:1498–1505.[Abstract/Free Full Text]
  8. Miravitlles M, Espinosa C, Fernandez-Laso E, Martos JA, Maldonado JA, Gallego M. Relationship between bacterial flora in sputum and functional impairment in patients with acute exacerbations of COPD: Study Group of Bacterial Infection in COPD. Chest 1999;116:40–46.[Abstract/Free Full Text]
  9. Kessler R, Faller M, Fourgaut G, Mennecier B, Weitzenblum E. Predictive factors of hospitalization for acute exacerbation in a series of 64 patients with chronic obstructive pulmonary disease. Am J Respir Crit Care Med 1999;159:158–164.[Abstract/Free Full Text]
  10. Wilson R. The role of infection in COPD. Chest 1998;113:242S–248S.[Medline]
  11. Dewan NA, Rafique S, Kanwar B, Satpathy H, Ryschon K, Tillotson GS, Niederman MS. Acute exacerbation of COPD: factors associated with poor treatment outcome. Chest 2000;117:662–671.[Abstract/Free Full Text]
  12. Grossman RF. The value of antibiotics and the outcomes of antibiotic therapy in exacerbations of COPD. Chest 1998;113:249S–255S.[Medline]
  13. Fagon JY, Chastre J. Severe exacerbations of COPD patients: the role of pulmonary infections. Semin Respir Infect 1996;11:109–118.[Medline]
  14. Arunabh, Fein AM. Management of acute exacerbations in chronic obstructive pulmonary disease. Curr Opin Pulm Med 2000;6:122–126.[CrossRef][Medline]
  15. Griffith DE, Mazurek GH. Pneumonia in chronic obstructive lung disease. Infect Dis Clin North Am 1991;5:467–484.[Medline]
  16. Ewig S, Torres A. Severe community-acquired pneumonia. Clin Chest Med 1999;20:575–587.[CrossRef][Medline]
  17. Zalacain R, Sobradillo V, Amilibia J, Barron J, Achotegui V, Pijoan JI, Llorente JL. Predisposing factors to bacterial colonization in chronic obstructive pulmonary disease. Eur Respir J 1999;13:343–348.[Abstract]
  18. Vegelin AL, Bissumbhar P, Joore JC, Lammers JW, Hoepelman IM. Guidelines for severe community-acquired pneumonia in the western world. Neth J Med 1999;55:110–117.[CrossRef][Medline]
  19. Takashima K, Tateda K, Matsumoto T, Ito T, Iizawa Y, Nakao M, Yamaguchi K. Establishment of a model of penicillin-resistant Streptococcus pneumoniae pneumonia in healthy CBA/J mice. J Med Microbiol 1996;45:319–322.[Abstract]
  20. Tateda K, Takashima K, Miyazaki H, Matsumoto T, Hatori T, Yamaguchi K. Noncompromised penicillin-resistant pneumococcal pneumonia CBA/J mouse model and comparative efficacies of antibiotics in this model. Antimicrob Agents Chemother 1996;40:1520–1525.[Abstract]
  21. Bedos JP, Azoulay-Dupuis E, Vallee E, Veber B, Pocidalo JJ. Individual efficacy of clarithromycin (A-56268) and its major human metabolite 14-hydroxy clarithromycin (A-62671) in experimental pneumococcal pneumonia in the mouse. J Antimicrob Chemother 1992;29:677–685.[Abstract/Free Full Text]
  22. LeVine AM, Reed JA, Kurak KE, Cianciolo E, Whitsett JA. GM-CSF-deficient mice are susceptible to pulmonary group B streptococcal infection. J Clin Invest 1999;103:563–569.[Medline]
  23. Barry B, Muffat-Joly M, Gehanno P, Pocidalo JJ. Effect of increased dosages of amoxicillin in treatment of experimental middle ear otitis due to penicillin-resistant Streptococcus pneumoniae. Antimicrob Agents Chemother 1993;37:1599–1603.[Abstract/Free Full Text]
  24. Karlinsky JB, Snider GL. Animal models of emphysema. Am Rev Respir Dis 1978;117:1109–1133.[Medline]
  25. Otto-Verberne CJ, Ten Have-Opbroek AA, Franken C, Hermans J, Dijkman JH. Protective effect of pulmonary surfactant on elastase-induced emphysema in mice. Eur Respir J 1992;5:1223–1230.[Abstract]
  26. Janoff A, Dearing R. Prevention of elastase-induced experimental emphysema by oral administration of a synthetic elastase inhibitor. Am Rev Respir Dis 1980;121:1025–1029.[Medline]
  27. Christensen TG, Korthy AL, Snider GL, Hayes JA. Irreversible bronchial goblet cell metaplasia in hamsters with elastase-induced panacinar emphysema. J Clin Invest 1977;59:397–404.
  28. Lucey EC, Goldstein RH, Stone PJ, Snider GL. Remodeling of alveolar walls after elastase treatment of hamsters: results of elastin and collagen mRNA in situ hybridization. Am J Respir Crit Care Med 1998;158:555–564.[Abstract/Free Full Text]
  29. Snider GL, Lucey EC, Stone PJ. Animal models of emphysema. Am Rev Respir Dis 1986;133:149–169.[Medline]
  30. Moore TA, Newstead MW, Strieter RM, Mehrad B, Beaman BL, Standiford TJ. Bacterial clearance and survival are dependent on CXC chemokine receptor-2 ligands in a murine model of pulmonary Nocardia asteroides infection. J Immunol 2000;164:908–915.[Abstract/Free Full Text]
  31. Takashima K, Tateda K, Matsumoto T, Iizawa Y, Nakao M, Yamaguchi K. Role of tumor necrosis factor alpha in pathogenesis of pneumococcal pneumonia in mice. Infect Immun 1997;65:257–260.[Abstract]
  32. O'Brien DP, Briles DE, Szalai AJ, Tu AH, Sanz I, Nahm MH. Tumor necrosis factor alpha receptor I is important for survival from Streptococcus pneumoniae infections. Infect Immun 1999;67:595–601.[Abstract/Free Full Text]
  33. Benton KA, VanCott JL, Briles DE. Role of tumor necrosis factor alpha in the host response of mice to bacteremia caused by pneumolysin-deficient Streptococcus pneumoniae. Infect Immun 1998;66:839–842.[Abstract/Free Full Text]
  34. Janoff EN, Fasching C, Orenstein JM, Rubins JB, Opstad NL, Dalmasso AP. Killing of Streptococcus pneumoniae by capsular polysaccharide-specific polymeric IgA, complement, and phagocytes. J Clin Invest 1999;104:1139–1147.[Medline]
  35. Standiford TJ, Wilkowski JM, Sisson TH, Hattori N, Mehrad B, Bucknell KA, Moore TA. Intrapulmonary tumor necrosis factor gene therapy increases bacterial clearance and survival in murine gram-negative pneumonia. Hum Gene Ther 1999;10:899–909.[CrossRef][Medline]
  36. Rezaiguia S, Garat C, Delclaux C, Meignan M, Fleury J, Legrand P, Matthay MA, Jayr C. Acute bacterial pneumonia in rats increases alveolar epithelial fluid clearance by a tumor necrosis factor-alpha-dependent mechanism. J Clin Invest 1997;99:325–335.[Medline]
  37. Takabatake N, Nakamura H, Abe S, Inoue S, Hino T, Saito H, Yuki H, Kato S, Tomoike H. The relationship between chronic hypoxemia and activation of the tumor necrosis factor-alpha system in patients with chronic obstructive pulmonary disease. Am J Respir Crit Care Med 2000;161:1179–1184.[Abstract/Free Full Text]
  38. Saito H, Nakamura H, Kato S, Inoue S, Inage M, Ito M, Tomoike H. Percutaneous in vivo gene transfer to the peripheral lungs using plasmid-liposome complexes. Am J Physiol Lung Cell Mol Physiol 2000;279:L651–L657.[Abstract/Free Full Text]
  39. Heemskerk-Gerritsen BA, Dijkman JH, Ten Have-Opbroek AA. Stereological methods: a new approach in the assessment of pulmonary emphysema. Microsc Res Tech 1996;34:556–562.[CrossRef][Medline]
  40. Saetta M, Shiner RJ, Angus GE, Kim WD, Wang NS, King M, Ghezzo H, Cosio MG. Destructive index: a measurement of lung parenchymal destruction in smokers. Am Rev Respir Dis 1985;131:764–769.[Medline]
  41. Fukuoka T, Kawada H, Kitayama A, Koga T, Kubota M, Harasaki T, Kamai Y, Ohya S, Yasuda H, Iwata M, et al. Efficacy of CS-834 against experimental pneumonia caused by penicillin-susceptible and -resistant Streptococcus pneumoniae in mice. Antimicrob Agents Chemother 1998;42:23–27.[Abstract/Free Full Text]
  42. Doerschuk CM, Mizgerd JP, Kubo H, Qin L, Kumasaka T. Adhesion molecules and cellular biomechanical changes in acute lung injury: Giles F. Filley Lecture. Chest 1999;116(Suppl 1):37S–43S.[Free Full Text]
  43. Raynolds HY. Integrated host defense against infections. In: Crystal RG, West JB, Barnes PJ, Weibel ER, editors. The lung: scientific foundations. 2nd ed. Philadelphia, PA: Lippincott-Raven Publishers; 1997. p. 2353–2365.
  44. Raynolds HY. Lung inflammation: normal host defence or a complication of some diseases. Ann Rev Med 1987;38:295–323.[Medline]
  45. Green GM, Kass EH. The role of alveolar macrophages in the clearance of bacteria from the lung. J Exp Med 1964;119:167–175.[Abstract]
  46. Abe S, Nakamura H, Inoue S, Takeda H, Saito H, Kato S, Mukaida N, Matsushima K, Tomoike H. Interleukin-8 gene repression by clarithromycin is mediated by the activator protein-1 binding site in human bronchial epithelial cells. Am J Respir Cell Mol Biol 2000;22:51–60.[Abstract/Free Full Text]
  47. Prieto A, Reyes E, Bernstein ED, Martinez B, Monserrat J, Izquierdo JL, Callol L, de LUCAS P, Alvarez-Sala R, Alvarez-Sala JL, et al. Defective natural killer and phagocytic activities in chronic obstructive pulmonary disease are restored by glycophosphopeptical (inmunoferon). Am J Respir Crit Care Med 2001;163:1578–1583.[Abstract/Free Full Text]
  48. Pilette C, Godding V, Kiss R, Delos M, Verbeken E, Decaestecker C, De Paepe K, Vaerman JP, Decramer M, Sibille Y. Reduced epithelial expression of secretory component in small airways correlates with airflow obstruction in chronic obstructive pulmonary disease. Am J Respir Crit Care Med 2001;163:185–194.[Abstract/Free Full Text]
  49. Aaron SD, Angel JB, Lunau M, Wright K, Fex C, Le Saux N, Dales RE. Granulocyte inflammatory markers and airway infection during acute exacerbation of chronic obstructive pulmonary disease. Am J Respir Crit Care Med 2001;163:349–355.[Abstract/Free Full Text]
  50. Mauderly JL, Bice DE, Cheng YS, Gillett NA, Griffith WC, Henderson RF, Pickrell JA, Wolff RK. Influence of preexisting pulmonary emphysema on susceptibility of rats to inhaled diesel exhaust. Am Rev Respir Dis 1990;141:1333–1341.[Medline]
  51. Gross P, deTreville RT. Emphysema and pneumoconiosis: an experimental study on their interrelationship. Arch Environ Health 1969;18:340–349.[Medline]
  52. Ruiz M, Ewig S, Marcos MA, Martinez JA, Arancibia F, Mensa J, Torres A. Etiology of community-acquired pneumonia: impact of age, comorbidity, and severity. Am J Respir Crit Care Med 1999;160:397–405.[Abstract/Free Full Text]
  53. Torres A, Serra-Batlles J, Ferrer A, Jimenez P, Celis R, Cobo E, Rodriguez-Roisin R. Severe community-acquired pneumonia: epidemiology and prognostic factors. Am Rev Respir Dis 1991;144:312–318.[Medline]
  54. Azoulay-Dupuis E, Vallee E, Veber B, Bedos JP, Bauchet J, Pocidalo JJ. In vivo efficacy of a new fluoroquinolone, sparfloxacin, against penicillin-susceptible and -resistant and multiresistant strains of Streptococcus pneumoniae in a mouse model of pneumonia. Antimicrob Agents Chemother 1992;36:2698–2703.[Abstract/Free Full Text]
  55. Bedos JP, Rieux V, Bauchet J, Muffat-Joly M, Carbon C, Azoulay-Dupuis E. Efficacy of trovafloxacin against penicillin-susceptible and multiresistant strains of Streptococcus pneumoniae in a mouse pneumonia model. Antimicrob Agents Chemother 1998;42:862–867.[Abstract/Free Full Text]
  56. Moine P, Vallee E, Azoulay-Dupuis E, Bourget P, Bedos JP, Bauchet J, Pocidalo JJ. In vivo efficacy of a broad-spectrum cephalosporin, ceftriaxone, against penicillin-susceptible and -resistant strains of Streptococcus pneumoniae in a mouse pneumonia model. Antimicrob Agents Chemother 1994;38:1953–1958.[Abstract/Free Full Text]
  57. Briles DE, Crain MJ, Gray BM, Forman C, Yother J. Strong association between capsular type and virulence for mice among human isolates of Streptococcus pneumoniae. Infect Immun 1992;60:111–116.[Abstract/Free Full Text]
  58. Crooks SW, Bayley DL, Hill SL, Stockley RA. Bronchial inflammation in acute bacterial exacerbations of chronic bronchitis: the role of leukotriene B4. Eur Respir J 2000;15:274–280.[Abstract]
  59. Hill AT, Bayley D, Stockley RA. The interrelationship of sputum inflammatory markers in patients with chronic bronchitis. Am J Respir Crit Care Med 1999;160:893–898.[Abstract/Free Full Text]



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