Comparison of sputum induction using high-output and low-output ultrasonic nebulizers in normal subjects and patients with COPD

SPLUNC1 promotes lung innate defense against Mycoplasma pneumoniae infection in mice

Short palate, lung, and nasal epithelium clone 1 (SPLUNC1) protein is highly expressed in normal airways, but is dramatically decreased in allergic and cigarette smoke exposure settings. We have previously demonstrated SPLUNC1 in vitro antibacterial property against Mycoplasma pneumoniae (Mp). However, its in vivo biological functions remain unclear. The objectives of this study were to determine the in vivo functions of SPLUNC1 following bacterial (eg, Mp) infection, and to examine the underlying mechanisms. We generated SPLUNC1-deficient mice and utilized transgenic mice overexpressing human SPLUNC1 exclusively within the airway epithelium. These mice were infected with Mp and, twenty-four hours post infection, their host defense responses were compared to littermate controls. Mp levels and inflammatory cells increased in the lungs of SPLUNC1(-/-) mice as compared to wild type controls. SPLUNC1 deficiency was shown to contribute to impaired neutrophil activation. In contrast, mice overexpressing hSPLUNC1 exclusively in airway epithelial cells demonstrated lower Mp levels. Furthermore, neutrophil elastase activity was significantly increased in mice overexpressing hSPLUNC1. Lastly, we demonstrated that SPLUNC1 enhanced Mp-induced human neutrophil elastase (HNE) activity, and HNE directly inhibited the growth of Mp. Our findings demonstrate a critical in vivo role of SPLUNC1 in host defense against bacterial infection, and likely provide a novel therapeutic approach to restore impaired lung innate immune responses to bacteria in patients with chronic lung diseases.

[Sputum induction in children: Technical development]

OBJECTIVE

To compare low and high flow nebulizers performance (total of samples) and its side effects on sputum induction in asthmatic children.

PATIENTS AND METHODS

Sputum induction was performed by inhalation of a hypertonic saline solution at increasing concentrations (3%, 4% and 5%) using low flow (OMRON NE-U07; flow rate 1ml/min), or high flow (OMRON NE-U12; flow rate 3ml/min, and DeVilbiss Ultraneb 3000; flow rate 2.5ml/min) ultrasonic nebulizers.

RESULTS

We performed 49 inductions in 49 patients from 7 to 15 years old (in 15 children we used a low flow nebulizer (Omron NE-U07) and in 34 children a high flow nebulizer (OMRON NEU12, 6 patients, and DeVilbiss Ultraneb 3000, 28 patients). We obtained 37 samples of which 36 had less than 20% of squamous cells, and 26 had a viability > or =60%. The test performance was higher with high-flow nebulizers, obtaining 85.3% of samples compared to 53% (p=0.04). A total of 69% of samples obtained with the high flow nebulizer were valid, compared to 62.5% (p=0.7) with the low flow nebulizers. With high flow rate nebulizers the incidence of cough (17.6%, p=0.08) and itchy eyes (0%, p=0.02) decreased with the low flow nebulizer (47% and 20% respectively), but bad taste (82.3%, p <0.001) and salivation (14.7%, p=0.3) increased.

CONCLUSIONS

With high flow rate ultrasonic nebulizers we obtain a higher performance of the technique without an increase in significant side effects.

Airway inflammation and anti-protease defences rapidly improve during treatment of an acute exacerbation of COPD

Background and objective:  There are few data on the short‐term natural history of airway inflammation during severe episodes of acute exacerbation of COPD (AECOPD). An observational study was performed to determine how rapidly conventional treatment improves airway inflammation in patients admitted to hospital with AECOPD.

Methods:  Twenty‐four consecutive patients with AECOPD were recruited and changes in sputum inflammatory indices were assessed after 2 and 4 days of treatment. The primary end‐points included presence of bacteria and viruses, changes in sputum total cell counts (TCC) and polymorphonuclear leukocyte (PMN) differential counts, and levels of secretory leukocyte protease inhibitor (SLPI), IL‐8 and TNF‐α.

Results:  All patients received oral corticosteroids and 17 (71%) were also treated with oral antibiotics. A bacterial or viral pathogen was isolated from 12 patients (50%), and Aspergillus fumigatus was isolated from one. A positive bacterial culture was associated with increased sputum TCC and PMN count (P < 0.05), as well as higher levels of IL‐8 and TNF‐α (P < 0.05), and a trend towards lower sputum SLPI levels (P = 0.06). Sputum PMN numbers fell by 70% within the first 48 h of admission (P < 0.05), accompanied by an increase in sputum SLPI (P < 0.001) and reductions in the levels of TNF‐α (P < 0.005) and IL‐8 (P = 0.06), with no further significant change at 4 days.

Conclusions:  Conventional treatment for severe AECOPD is associated with rapid reduction of neutrophilic inflammation and improvement in anti‐protease defences.

Dysregulated apoptosis and NFkappaB expression in COPD subjects

BACKGROUND

The abnormal regulation of neutrophil apoptosis may contribute to the ineffective resolution of inflammation in chronic lung diseases. Multiple signalling pathways are implicated in regulating granulocyte apoptosis, in particular, NFkappaB (nuclear factor-kappa B) signalling which delays constitutive neutrophil apoptosis. Although some studies have suggested a dysregulation in the apoptosis of airway cells in chronic obstructive pulmonary disease (COPD), no studies to date have directly investigated if NFkappaB is associated with apoptosis of airway neutrophils from COPD patients. The objectives of this study were to examine spontaneous neutrophil apoptosis in stable COPD subjects (n = 13), healthy smoking controls (n = 9) and non-smoking controls (n = 9) and to investigate whether the neutrophil apoptotic process in inflammatory conditions is associated with NFkappaB activation.

METHODS

Analysis of apoptosis in induced sputum was carried out by 3 methods; light microscopy, Annexin V/Propidium iodide and the terminal transferase-mediated dUTP nick end-labeling (TUNEL) method. Activation of NFkappaB was assessed using a flow cytometric method and the phosphorylation state of IkappaBalpha was carried out using the Bio-Rad Bio-Plex phosphoprotein IkappaBalpha assay.

RESULTS

Flow cytometric analysis showed a significant reduction in the percentage of sputum neutrophils undergoing spontaneous apoptosis in healthy smokers and subjects with COPD compared to non-smokers (p < 0.001). Similar findings were demonstrated using the Tunel assay and in the morphological identification of apoptotic neutrophils. A significant increase was observed in the expression of both the p50 (p = 0.006) and p65 (p = 0.006) subunits of NFkappaB in neutrophils from COPD subjects compared to non-smokers.

CONCLUSION

These results demonstrate that apoptosis is reduced in the sputum of COPD subjects and in healthy control smokers and may be regulated by an associated activation of NFkappaB.

Quality of life and inflammation in exacerbations of bronchiectasis

Patients with bronchiectasis often have impaired quality of life (QoL), which deteriorates with exacerbations. The aim of this study was to investigate changes in QoL and how these were influenced by changes in airway physiology and inflammation in patients with bronchiectasis before and after resolution of an exacerbation. Sputum induction and a QoL questionnaire were undertaken on the first day, day 14, and 4 weeks after completion of intravenous antibiotics (day 42). Eighteen patients (12 female) were recruited, median (IQ range) age of 54 (47–60) years. There was a trend towards an improvement in lung function from visit 1 to visit 2, but this was not statistically significant. C-reactive protein (CRP) [mean (SEM)] reduced between visit 1 and visit 2 [55.4 (21.5) vs 9.4 (3.1) mg/L, P = 0.03] but did not increase significantly on visit 3 [44.4 (32.9) mg/L, P = 0.27]. The median (interquartile range) sputum cell count (×106 cells/g of sputum) decreased from visit 1 to visit 2 [21.6 (11.8–37.6)–13.3 (6.7–22.9) × 106 cells/g, respectively, P = 0.008] and increased from visit 2 to visit 3 [26.3 (14.1–33.6) × 106 cells/g, P = 0.03]. All soluble markers of inflammation significantly reduced from visit 1 to visit 2 but increased on visit 3 with the exception of TNF-α. Regarding QoL, three of the four domains (dyspnoea, emotional, mastery) significantly improved from visit 1 to visit 2 but did not change between visit 2 and visit 3. The improvements in QoL scores could not be explained by the improvements in lung function or inflammatory markers.

Safety of sputum induction during exacerbations of COPD

Sputum induction (SI) is considered to be a safe tool for assessing airway inflammation in stable patients with COPD, but little is known about its safety during exacerbations. We therefore assessed the safety of SI during COPD exacerbations. SI data from 44 COPD patients were assessed both in the stable phase and during exacerbation. The median FEV1 for the stable phase and exacerbation were 61% predicted (interquartile range [IQR], 49 to 74% predicted) and 51% predicted (IQR, 45 to 60% predicted), respectively. The median decrease in FEV(1) with SI during an exacerbation was 0.27 L (IQR, 0.17 to 0.40 L) vs 0.28 L (IQR, 0.22 to 0.44 L) during the stable phase (p = 0.03). The patients experienced the associated dyspnea well; no other adverse events occurred. All FEV1 values returned to within 90% of their initial value within 30 min. A larger decrease in FEV1 due to SI during an exacerbation was associated with the following parameters in the stable phase of disease: lower total sputum cell count (r = -0.37; p = 0.01); higher percentage of eosinophils (r = 0.33; p = 0.04); and a larger decrease in FEV1 after SI (r = 0.39; p = 0.03). In a multivariate analysis, the only independent association was with the larger decrease in FEV1 in the stable phase. We concluded that SI can be safely carried out in patients with mild-to-moderate COPD who experience an exacerbation, and this occurs with no greater risk than in stable patients with COPD.

Safety of sputum induction in moderate-to-severe smoking-related chronic obstructive pulmonary disease

BACKGROUND

Investigation of the safety of sputum induction in patients with moderate-to-severe chronic obstructive pulmonary disease (COPD) has been limited.

OBJECTIVE

to evaluate this issue in 100 patients with a mean FEV1 of 1.2 (0.4) L. After 200 microg inhaled salbutamol, sputum induction was performed with inhaled saline in increasing and tailored concentrations (0.9% to 5%) until an adequate sample of sputum was obtained or the FEV1 fell by >20%.

MAIN FINDINGS

Sputum induction was successful in 92% of occasions. The mean (SD) fall in FEV1 was 13.5 (8.6)%. Five patients had a fall >20% but all recovered to 10% of baseline after inhaled salbutamol. The magnitude of fall in FEV1 correlated weakly with salbutamol reversibility (r = 0.37, p < 0.001), baseline FEV1/VC (r = -0.32, p = 0.001) and baseline FEV1% predicted (r = -0.36, p = 0.003) but not with age, smoking history or post-Salbutamol FEV1. Principle

CONCLUSION

Sputum induction can be performed safely using a patient-tailored approach in patients with moderate-to-severe COPD, supporting its use in research and clinical practice.

Neutrophil cell death, activation and bacterial infection in cystic fibrosis

BACKGROUND

Cystic fibrosis (CF) is characterised by chronic endobronchial bacterial infection and neutrophil mediated inflammation. Neutrophil apoptosis is essential for the resolution of inflammation. This study assessed the relationship between levels of neutrophil apoptosis and sputum microbiology in matched clinically stable patients with CF.

METHODS

Sputum was induced from 34 patients (nine with no Gram negative infection, 10 colonised with Pseudomonas aeruginosa, 10 with Burkholderia cenocepacia, and five with other infections). Apoptotic neutrophils measured by flow cytometric Annexin V/propidium iodide staining and morphology were similar in all groups.

RESULTS

Patients infected with P aeruginosa or B cenocepacia had a significantly lower percentage of viable neutrophils in the sputum than those with no Gram negative infection (Kruskal-Wallis p = 0.01, median (interquartile range (IQR)) 14.2% (9.4-21.6), 15.8% (12.3-19.5), and 48.4% (23.0-66.4); p = 0.003 and p = 0.002, respectively). They also had significantly higher levels of secondary necrotic granulocytes in sputum than patients with no Gram negative infection (Kruskal-Wallis p<0.0001, median (IQR) 55.5% (48.4-64.5), 50.4% (44.6-61.9), and 24.8% (14.4-30.5); p<0.0001 and p<0.0001, respectively). Neutrophils (x 10(6)/g sputum) in P aeruginosa infected patients (Kruskal-Wallis p = 0.05, median (IQR) 6.3 (3.5-12.7)) and B cenocepacia infected patients (5.7 (1.5-14.5)) were significantly higher than in the group with no Gram negative infection (0.5 (0.5-4.3), p = 0.03 and 0.04, respectively).

CONCLUSION

These results suggest that cell death and clearance may be altered in patients with CF colonised with P aeruginosa and B cenocepacia compared with those with no Gram negative infection.

Neutrophil apoptosis, proinflammatory mediators and cell counts in bronchiectasis

BACKGROUND

Lower airway secretions from patients with bronchiectasis show inflammatory cell infiltration and increased proinflammatory mediators. The aim of this study was to investigate the effects of antibiotic treatment for exacerbations on neutrophil apoptosis and necrosis.

METHODS

Sputum was induced from 15 subjects with idiopathic bronchiectasis at the beginning of an acute exacerbation and after intravenous antibiotic treatment. Neutrophil apoptosis and necrosis were assessed using flow cytometry and morphology and the supernatant was analysed for concentrations of inflammatory mediators.

RESULTS

Neutrophil numbers (x10(6) cells/g sputum) in sputum were significantly greater on day 0 than on day 14 (median difference (95% confidence interval (CI)) 5.14 (1.27 to 8.46), p = 0.02). Controls had a significantly higher percentage of sputum macrophages than patients with bronchiectasis (day 0, 1.35 (95% CI 0.48 to 2.89), p = 0.004; day 14, 1.09 (95% CI 0.26 to 2.86), p = 0.02). The concentrations of tumour necrosis factor alpha (pg/ml), interleukin 8 (ng/ml), and neutrophil elastase (ng/ml) in sputum supernatant were significantly reduced on day 14 compared with day 0 (median difference -94 (95% CI -158 to -27), p = 0.005; -106 (95% CI -189 to -50), p = 0.0006; and -73 451 (95% CI -135 495 to -12 303), p = 0.02 respectively). Patients with bronchiectasis had a significantly lower percentage of cells which were neither apoptotic nor necrotic than healthy controls (both days, -38.8 (95% CI -49.6 to -8.5), p = 0.002; -45.0 (95% CI -58.0 to -34.1), p = 0.0003, respectively), and on day 14 they had a significantly higher percentage of secondary necrotic cells than healthy controls (40 (95% CI 11.6 to 57.5), p = 0.004).

CONCLUSIONS

This study shows that antibiotic treatment affects concentrations of proinflammatory mediators and cell death and clearance may be altered in bronchiectasis.

Sputum induction: review of literature and proposal for a protocol

Since the 1980s, sputum induction by inhalation of hypertonic saline has been successfully used for diagnosing Pneumocystis carinii pneumonia in patients infected with HIV. In recent years, sputum induction and its subsequent processing has been refined as a noninvasive research tool providing important information about inflammatory events in the lower airways, and it has been used for studying various illnesses. In asthma, one application is to use sputum inflammatory indices to increase our understanding of complex relationships between inflammatory cells, mediators, and cytokine mechanisms. In chronic obstructive pulmonary disease, sputum assessment could be used as a screening test before deciding on long-term corticosteroid treatment. In tuberculosis, sputum induction is a valuable diagnostic tool for HIV-seropositive patients who do not produce sputum. Sputum induction appears to be a relatively safe, noninvasive means of obtaining airway secretions from subjects with cystic fibrosis, especially from those who do not normally produce sputum. Moreover, sputum induction can also be used in chronic cough and lung cancer. Generally, induction is performed through ultrasonic nebulizers, using hypertonic saline. It is recommended that sputum be processed as soon as possible, with complete homogenization by the use of dithiothreitol. We have also shown in this article an example of a protocol for inducing and processing sputum employing a nebulizer produced in Brazil.