Ozone-induced airway inflammatory changes differ between individuals and are reproducible

To study whether the individual inflammatory response to ozone was reproducible, dose-dependent, and time-dependent, we performed two exposures to 250 ppb ozone, one to 125 ppb and one to filtered air, each for 3 h of intermittent exercise and separated by at least 1 wk. Twenty-one healthy and 15 asthmatic subjects participated in the study. One hour after the two exposures to 250 ppb ozone we observed a mean increase in sputum neutrophils of 17.9 and 17.9% in healthy and of 20.3 and 15.2% in asthmatic subjects (p < 0.05 each). Twenty-four hours after exposure, the respective values were 11.9 and 14.8%, and 9.1 and 16.1% (p < 0.05 each). In the whole group of subjects, individual changes in the percentage of neutrophils were significantly correlated between the two exposure days 1 h (r = 0.87, p < 0.001; intraclass correlation coefficient [Ri] = 0.86) as well as 24 h (r = 0.79, p < 0.001; Ri = 0.71) after exposure. The percentages of lymphocytes were increased 24 h after exposures (all subjects combined: p < 0.05). The decrease in FEV1 in both groups (p < 0.01), was also reproducible (r = 0.77, p < 0.001), but there were no correlations between changes in sputum parameters and lung function. Exposure to 125 ppb ozone caused a small increase (p < 0. 05) in the percentage of neutrophils in asthmatic subjects and in the concentrations of interleukin-8 in both groups combined. Our data demonstrate that inflammatory and lung function responses to ozone differ between individuals and are reproducible but not related to each other. Therefore, these responses appear to represent two independent factors underlying the airway response to ozone.

Induced sputum in adolescents with severe stable asthma. Safety and the relationship of cell counts and eosinophil cationic protein to clinical severity

This study examined the safety of sputum induction and the relation between sputum cell counts and clinical parameters in adolescents with severe persistent asthma. Within 5 days, induced sputum and reversibility in forced expiratory volume in one second (FEV1), quality of life, provocative concentration causing a 20% fall in FEV1 (PC20) of adenosine monophosphate and histamine, exercise-induced bronchoconstriction, overall asthma severity index, and blood eosinophils were collected in 20 atopic adolescents with moderate-to-severe persistent asthma (12-18 yrs of age, FEV1 65-110% of predicted, on 500-2,000 microg inhaled steroids daily). FEV1 was reversible by 13.3-2.3% pred. After sputum induction, FEV1 was still increased by 9.0+/-2.6% pred as compared to the pre-salbutamol baseline. Sputum contained, median (range): 12.4 (0.4-59.5)% squamous cells, 47.3 (6.8-84.0)% macrophages, 39.0 (4.6-84.8)% neutrophils, 4.8 (1.0-12.4)% lymphocytes, 0.4 (0-10.8)% eosinophils and 3.6 (0-23.4)% bronchial epithelial cells. Sputum eosinophils showed a trend towards a significant association with the overall asthma severity index (r=0.46, p=0.06) and correlated inversely with baseline FEV1 (r=-0.51, p=0.03). In conclusion, sputum can be induced safely in adolescents with moderate-to-severe persistent asthma, if pretreated with beta2-agonists. Despite relatively low sputum eosinophil counts in these patients on inhaled steroids, the association of eosinophil numbers with baseline forced expiratory volume in one second and asthma severity index favours a role of induced sputum in monitoring adolescents with severe asthma.

Analysis of induced sputum: a new approach to the study of airway inflammation in asthma

Induced sputum is a simple method that enables the analysis of lower respiratory tract material obtained through non-invasive methods. Validation of the technique for the study of airway inflammation in asthma and other respiratory diseases, together with the most relevant findings reported in the literature, are reviewed herein. Accurate methods that can be applied to the analysis of induced sputum samples, such as immunocytochemistry, flow cytometry or polymerase chain reaction are also discussed.

Diagnosing occupational asthma: use of induced sputum

The diagnosis of occupational asthma (OA) needs to be made with as much objective evidence as possible. If there is airway inflammation, measurement of this should be an asset. The objective of this study was to investigate whether there is an increase in induced sputum and blood eosinophils and eosinophil cationic protein (ECP) in OA after work exposure. Patients were assessed after a 2-4 week period at work and away from work with cell counts and ECP assays performed blind to the clinical data. They were considered to have OA if symptoms were worse at work and there was a fall in forced expiratory volume in one second (FEV1) > or =20% or in the provocative concentration of methacholine causing a 20% fall in FEV1 (PC20) of four-fold or more compared with away from work. Patients whose symptoms were worse at work but had a change in FEV1 of <20% and in methacholine PC20 of less than four-fold were considered as controls. Sixteen patients were studied. Ten had OA and six were controls. Patients with OA had a significant increase in median (interquartile range) sputum eosinophils and ECP when at work compared with the periods out of work, 10.0 (17.05) versus 0.8 (1.6)% (p=0.007) and 3,840 (6,076) versus 116 (180) microg x L(-1) (p=0.01). They also had a higher blood eosinophil count, 0.3 (0.5) x 10(9) versus 0.2 (0.1) x 10(9) x L(-1) (p=0.013), and a trend towards higher serum ECP levels, 44.0 (20.0) versus 32.0 (18.5) microg x L(-1) (p=0.07). In conclusion, the proportion of eosinophils and levels of eosinophil cationic protein in sputum are particularly high at work in patients with occupational asthma, suggesting that the measurement of these factors can supplement other physiological outcomes in establishing the diagnosis of occupational asthma.

Sputum eosinophils and exhaled nitric oxide during late asthmatic reaction in patients with western red cedar asthma

Examination of sputum for eosinophils and measurement of exhaled nitric oxide have been proposed as noninvasive methods of assessing airway inflammation in asthma. The use of these tests in the evaluation of patients with occupational asthma has not been reported. This study investigated the changes in sputum eosinophils and exhaled NO before and at intervals after inhalation challenge with plicatic acid in patients with suspected western red cedar asthma. Of 17 subjects who underwent challenge, nine had a positive bronchoconstrictor reaction (responders) and eight had a negative reaction (nonresponders). At 6 and 24 h after plicatic acid challenge, there was a significant increase in sputum eosinophils among responders, which was inversely related to the fall in forced expiratory volume in one second (FEV1) at 6 h. An increase in sputum eosinophils was also found in three nonresponders. Levels of exhaled NO increased at 24 h after challenge with plicatic acid in both responders and nonresponders, being significant only in nonresponders. No correlation was found between the increase in nitric oxide and the magnitude of the functional changes in the airways. There were significant correlations between the degree of sputum eosinophilia and the level of exhaled NO before and after methacholine and plicatic acid challenge. In conclusion, the late asthmatic reaction induced by plicatic acid in patients with western red cedar asthma is associated with an increase in sputum eosinophils. The usefulness of measuring sputum eosinophils and exhaled nitric oxide in the clinical evaluation of patients with suspected occupational asthma caused by low molecular weight compounds has yet to be determined.

Airway inflammatory response to ozone in subjects with different asthma severity

The aim of this study was to evaluate whether ozone exposure induces a similar airway inflammatory response in subjects with different degrees of asthma severity. Two groups of asthmatic subjects were studied: seven with intermittent mild asthma not requiring regular treatment (group A); and seven with persistent mild asthma requiring regular treatment with inhaled corticosteroids and long-acting beta2-agonists (group B). All subjects were exposed, in a randomized cross-over design, to air or O3 (0.26 parts per million (ppm) for 2 h with intermittent exercise); subjects in group B withdrew from regular treatment 72 h before each exposure. Before the exposure, and 1 and 2 h after the beginning of the exposure they performed a pulmonary function test, and a questionnaire was completed to obtain a total symptom score (TSS). Six hours after the end of the exposure, hypertonic saline (HS) sputum induction was conducted. Sputum cell percentages, eosinophil cationic protein (ECP) and interleukin (IL)-8 concentrations in the sputum supernatant were measured. TSS significantly increased and forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) significantly decreased after O3 exposure in comparison with air exposure in group A, whereas no changes were observed in group B except for a significant decrement of FEV1 2 h after the beginning of O3 exposure. Sputum neutrophil percentage was significantly higher after O3 exposure than after air exposure in both groups (Group A: 70.2% (28-87) versus 26.6% (8.6-73.2); Group B: 62.1% (25-82.4) versus 27.9% (14.4-54)). IL-8 was higher in sputum supernatant collected 6 h after O3 exposure than after air, only in group A. No change due to O3 has been found in sputum eosinophil percentage and ECP concentration in both groups. In conclusion, the degree of airway response to a short-term exposure to ozone is different in subjects with asthma of different severity. The available data do not allow elucidation of whether this difference depends on the severity of the disease or on the regular anti-inflammatory treatment.

Sputum analysis, bronchial hyperresponsiveness, and airway function in asthma: results of a factor analysis

BACKGROUND

Recent studies have shown weak associations among FEV1, bronchial hyperresponsiveness (BHR), sputum eosinophils, and sputum eosinophil cationic protein (ECP), suggesting that they are nonoverlapping quantities. The statistical method of factor analysis enables reduction of many parameters that characterize the disease to a few independent factors, with each factor grouping associated parameters.

OBJECTIVE

The purpose of this study was to demonstrate, by using factor analysis, that reversible airway obstruction, BHR, and eosinophilic inflammation of the bronchial tree, as assessed by cytologic and biochemical analysis of sputum, may be considered separate dimensions that characterize chronic bronchial asthma.

METHODS

Ninety-nine clinically stable patients with a previous diagnosis of asthma underwent spirometry, sputum induction, and histamine inhalation tests.

RESULTS

Most patients were nonobstructed (FEV1, 91% +/- 20%); a low level of bronchial reversibility (FEV1 increase after beta2 -agonist, 7.8% +/- 9.2%) and BHR (histamine PC20 FEV1 geometric mean, 0.98 mg/mL) were found. Sputum eosinophil differential count (12.4% +/- 17.7%) and sputum ECP (1305 +/- 3072 microg/mL) were in the normal range of our laboratory in 38 and 22 patients, respectively. Factor analysis selected 3 different factors, explaining 74.8% of variability. Measurements of airway function and age loaded on factor I, PC20 FEV1 and beta2 -response loaded on factor II, and sputum ECP and eosinophils loaded on factor III. Additional post hoc factor analyses provided similar results when the sample was divided into 2 subgroups by randomization, presence of airway obstruction, degree of BHR, percentage of sputum eosinophils, or concentration of sputum ECP.

CONCLUSIONS

We conclude that airway function, baseline BHR, and airway inflammation may be considered separate dimensions in the description of chronic asthma. Such evidence supports the utility of routine measurement of all these dimensions.

Between-observer repeatability of sputum differential cell counts. Influence of cell viability and squamous cell contamination

BACKGROUND

Induced sputum differential cell counts have been advocated as a method of noninvasively assessing airway inflammation in asthma and other airway diseases. Relatively little is known about the between-observer repeatability of sputum differential cell counts and the factors that influence it.

OBJECTIVE

To assess the between-observer variability of induced sputum cell counts.

METHODS

Sputum was induced and processed using standard techniques. Forty-two slides from 38 patients (31 with asthma, seven normal subjects) were randomly selected. Slides were classified as good (<20% squamous cells and >50% viability; n = 24); low viability (<50% viability; n = 10) and high squamous cell contamination (>20% squamous cells; n = 8). Two blinded observers counted between 200 and 400 nonsquamous cells and agreement was assessed by the intraclass correlation coefficient (ICC) and the standard deviation of between-observer differences (SD).

RESULTS

The overall ICC were 0.9, 0.89, 0.9 for eosinophils, neutrophils and macrophages and 0.29 and 0.69 for lymphocytes and epithelial cells. Repeatability was greater in slides classified as good compared with slides with low cell viability and particularly excess squamous cell contamination.

CONCLUSIONS

We have shown that the overall between-observer repeatability of the differential eosinophil, neutrophil and macrophage cell counts is good. Low cell viability and particularly excess squamous cell contamination reduce between-observer repeatability suggesting that techniques that ensure high cell viability and reduce squamous contamination would be an advantage.

Suppressive activity of bronchial macrophages recovered by induced sputum

BACKGROUND

The immunomodulatory activity of macrophages was shown to be a crucial mechanism in the pathogenesis of asthma.

METHODS

Induced sputum (IS) and methacholine challenge (MC) were carried out in 21 atopic subjects. Suppressive activity (SA) of sputum macrophages (SMO) was investigated on autologous peripheral lymphocytes (APL) proliferation in 12 of these patients and compared to the MC.

RESULTS

In 10 of the 21 patients, the FEV1 was >80%; five of these had a nonreactive MC. Eosinophils and metachromatic cells correlated well (r=0.6442; P=0.0029), but not with the MC. The SA of SMO correlated (P=0.0152) with the MC: SMO enhanced APL proliferation in five patients with a positive MC, while SMO showed SA in five with a negative MC. Only two patients with suppressive SMO had a positive MC. Cytokine profiles from five patients showed that two patients with a negative MC had interleukin (IL)-1alpha and beta, IL-6, and transforming growth factor (TGF)-beta transcripts, while two patients with a positive MC transcripted IL-4 and IL-5. One patient with a borderline MC transcripted IL-5, but not IL-4.

CONCLUSIONS

These data support the theory that patients with reduced suppressive bronchial macrophages display clinical bronchial hyperreactivity.

Objective quantitative analysis of eosinophils and bronchial epithelial cells in induced sputum by laser scanning cytometry

BACKGROUND

Sputum induction is an important non-invasive technique for measuring airway inflammation in asthma. Cell numbers are often too low for flow cytometric analysis. Laser scanning cytometry (LSC) is a novel technique that allows objective multicolour fluorescence analysis of cells on a microscope slide.

METHODS

LSC was used to determine sputum eosinophil and bronchial epithelial cell counts. We first confirmed that we could measure eosinophil counts accurately in peripheral blood using alpha-major basic protein (MBP) immunofluorescent staining. Sputum induction was performed according to standard protocols. Sputum samples from eight normal controls and 12 asthmatic patients were analysed by LSC and manual counting by two independent observers. Octospot cytospins were fixed and stained with mouse-alpha-human-MBP monoclonal antibody or mouse-alpha-human-cytokeratin antibody and goat-alpha-mouse Oregon Green conjugated second antibody.

RESULTS

Sputum induction provided a mean (SE) of 0.99 (0.2) x 10(6) cells per donor. More than 3000 cells on three cytospins per slide were analysed per cell type. The intraclass correlation coefficient (R) and standard deviation (SD) of differences in eosinophils determined by manual counting and LSC were 0.9 and 2.1, respectively, and for bronchial epithelial cell counts they were 0.7 and 2.0. Selective detection of labelled cells was confirmed visually after relocation.

CONCLUSION

Eosinophils and bronchial epithelial cells can be accurately and reproducibly counted in an objective manner. LSC is therefore a potentially powerful new method for immunophenotyping leucocytes and epithelial cells objectively in induced sputum in patients with asthma.

The effect of montelukast (MK-0476), a cysteinyl leukotriene receptor antagonist, on allergen-induced airway responses and sputum cell counts in asthma

BACKGROUND

Cysteinyl leukotrienes are capable of inducing chemotaxis of eosinophils in vitro and within the airways of animals and humans in vivo.

OBJECTIVE

We hypothesized that montelukast (MK-0476), a potent cysLT1 receptor antagonist, would protect against allergen-induced early (EAR) and late (LAR) asthmatic responses by virtue of anti-inflammatory properties. Hence, we studied the effect of pretreatment with oral montelukast on allergen-induced airway responses. As an exploratory endpoint, changes in inflammatory cell differentials and eosinophil cationic protein (ECP) were evaluated in hypertonic saline-induced sputum.

METHODS

Twelve asthmatic men (20-34 years, FEV1 79-109% predicted, histamine PC20FEV1 <4 mg/mL) with dual responses to inhaled house dust mite extract participated in a two-period, double-blind, placebo-controlled, crossover study. Three oral doses of montelukast (10 mg) or matching placebo were administered 36 and 12 h before, and 12 h post-allergen. The airway response to allergen was measured by FEV1, and the EAR and LAR were expressed as the corresponding areas under the time-response curves (AUC0-3 h and AUC3-8h, respectively). During each study period, sputum was induced with 4.5% NaCl 24 h before and 24 h after a standardized allergen challenge. Processed whole sputum cytospins were stained with Giemsa, and cell counts expressed as percentage nonsquamous cells. ECP was measured by FEIA in sputum supernatants.

RESULTS

All subjects completed the study. The changes in baseline FEV1 were not significantly different between the two pretreatments (P = 0.183). Montelukast significantly inhibited the EAR and LAR, reducing the AUC0-3h by 75.4% (P<0.001) and the AUC3-8h by 56.9% (P = 0.003) as compared with placebo. Sputa of nine subjects could be included in the analysis (<80% squamous cells). Allergen challenge significantly increased sputum eosinophils after placebo (mean change +/- SD: 4.8 +/- 5.8%, P = 0.038), with a similar trend after montelukast (mean change +/- SD: 4.1 +/- 5.4%; P = 0.056). The allergen-induced changes in sputum eosinophils and ECP, however, were not significantly different between the two pretreatments (P = 0.652 and P = 0.506, respectively).

CONCLUSION

We conclude that oral montelukast protects against allergen-induced early and late airway responses in asthma. However, using the present dosing and sample size, this protection was not accompanied with changes in sputum eosinophil percentage or activity, which may require more prolonged pretreatment with cysLT1 receptor antagonists.

Focal enhanced areas of the liver on computed tomography in a patient with superior vena cava obstruction

We present a patient with superior vena cava (SVC) obstruction in whom two areas of increased hepatic enhancement within the left lobe were seen on abdominal computed tomography (CT). The significance of this case is that abnormal enhancements of the liver on abdominal CT in the regions described should be suggestive of an SVC obstruction on this basis alone.

Protective effects of inhaled PGE2 on allergen-induced airway responses and airway inflammation

Inhalation of prostaglandin E2 (PGE2) had been reported to prevent allergen-induced bronchoconstrictor responses; however, the effects of inhaled PGE2 on allergen-induced airway inflammation or hyperresponsiveness after allergen are unknown. This study examined the effects of inhaled PGE2 on allergen-induced airway responses and inflammation. Eight mild asthmatics with a dual airway response to inhaled allergen were recruited into a double-blind randomized crossover study comparing the effects of inhaled PGE2 (100 microgram) or placebo, on allergen-induced changes in FEV1 measured for 7 h, induced sputum inflammatory cells, obtained at baseline, 7 and 24 h, and methacholine airway responsiveness measured at 24 h after challenge. Inhaled PGE2 attenuated the allergen-induced early fall in FEV1 from 24.4 +/- 3.6% after placebo to 10.3 +/- 2.5% after PGE2 (p = 0.002), the late fall in FEV1 from 21.2 +/- 2.7% after placebo to 12.6 +/- 3.6% after PGE2 (p = 0.03), allergen-induced methacholine airway hyperresponsiveness (p = 0.03) and allergen-induced increases in percent sputum eosinophils from 36.3 +/- 8.8% after placebo to 21.0 +/- 7.3% after PGE2 (p = 0.01), percentage of EG2+ cells (p = 0.02), and percentage of metachromatic cells (p = 0.02). These results indicate that inhaled PGE2 attenuates allergen-induced airway responses, hyperresponsiveness, and inflammation, when given immediately before inhaled allergen.

Semiautomated monolayer preparation of bronchial secretions using AutoCyte PREP

OBJECTIVE

Development of a method for semiautomated preparation of purified, representative and conventionally stained monolayer smears from bronchial secretions suitable for subjective and/or automated cytodiagnosis.

STUDY DESIGN

Bronchial secretions from 50 patients with and 48 without carcinoma cells of different types were collected in Saccomanno's fixative. After routine pick-and-smear processing, residual material was subjected to a mucolytic agent (ammonium thioglycolate). Separation of cells was performed by differential centrifugation through aqueous sucrose. The pellet was automatically processed by the AutoCyte PREP system.

RESULTS

Slides revealed well-preserved, slightly shrunken, homogeneously distributed cells devoid of mucus, cellular debris and bacteria in monolayer arrangement nearly without overlap. Granulocytes were eliminated to a large extent. Comparison with pick-and-smear specimens showed more tumor cells per square centimeter of slide surface in 100% of AutoCyte PREP slides. The number of tumor cells per AutoCyte PREP slide was higher in 46% and lower in 54%. Selecting slides at random and requiring at least 10 abnormal cells to establish a tumor diagnosis were achieved in 82.7% if only one, in 88.0% if two and 94.0% if seven or eight AutoCyte PREP slides were investigated.

CONCLUSION

The semiautomated method yielded conventionally stained, purified monolayer smears from bronchial secretions with cellular morphology suitable for evaluation by cytologists and screening machines. Representativity of AutoCyte PREP monolayers was superior to that of pick-and-smear slides.

[The effect of sex factors on cytologic changes in the sputum of young adults exposed to urban air pollution]

The harmful effect of occupational and urban air pollution on the function and structure of the respiratory tract has been proved. The severity and incidence of epithelial changes are in direct relation to duration of exposure and age of the examined population groups [1]. Squamous metaplasia of bronchial epithelium is an indicator of predisposition to chronic obstructive pulmonary disease and lung cancer [1-5]. Due to its topography and the development of industry and traffic, Sarajevo used to be the city with an extremely high level of air pollution [10-12]. Some studies in adults showed that the respiratory tract exposed to air pollution responded with more severe changes in men than in women [7-9]. The aim of this study was to compare cytological changes in sputa, depending on the sex of young adults exposed to a high level of urban air pollution, and to examine whether a big difference in duration of exposure has an effect on these relations.

MATERIALS AND METHODS

The subjects in the study were young adults, university students (21 to 25 years of age), all non-smokers. At the time of sputa collection (March-April 1991) they were clinically healthy with no history of chronic and serious acute respiratory diseases. They were divided into two groups according to the duration of air pollution exposure. The first group included those who had been living in Sarajevo since birth. The second group included those who used to live in pollution-free areas, but for the last two to three years had been living in Sarajevo where they came to attend the University (Table 1). Specimens were early morning spontaneously produced sputa, expectorated directly into Saccomanno's fixative and after centrifugation immersed in paraffin. Nine sections from each block were cut and stained with haematoxylin and eosin. The differences between cytological findings were tested with Hi2 test and Fisher's exact test, regarding sex and duration of exposure to air pollution.

RESULTS

The findings are summarized in Table 1. As many as 63% and 64% of the subjects from the first and the second group, respectively, were able to produce sputum, while the others produced saliva only. All sputa contained abnormal bronchial columnar cells and half of them contained respiratory spirals (Figures 1 and 2). Squamous metaplastic cells were found in 7% and 9% of subjects in the first and second group, respectively. These cells showed no evidence of atypia. Statistical tests failed to identify significant differences in the incidence of cytological findings between the groups regarding both the sex of the subjects and duration of their exposure to air pollution (Table 2).

DISCUSSION

The ability to produce sputum with the frequent presence of respiratory spirals in both groups of our subjects indicate an extremely harmful effect of smog. However, the incidence of squamous metaplastic cell findings was less severe comparing to adults and the elderly urban population. In the elderly (65 to 105 years of age) severe epithelial changes developed spontaneously in the absence of any other known aetiological factor [8, 9]. The increase in severity of changes in the course of aging, in our opinion, due to a gradual decline in efficiency of the defence mechanisms and regenerative potential of the respiratory system. The experimental study showed a decline of the efficiency of mucociliary clearance [14] as well as the damage of the function and decrease in number of alveolar macrophages in lung parenchyma and bronchoalveolar lavage [15, 16]. Trying to answer the question why the sex-related differences in the severity and incidence of epithelial changes appear in the groups of adults and the elderly, it is presumed that in aging the defence and regenerative potentials decline more rapidly in men than in women. (ABSTRACT TRUNCATED)

Neutrophil elastase and elastase-rich cystic fibrosis sputum degranulate human eosinophils in vitro

Neutrophils, eosinophils, and their proinflammatory constituents are important mediators of airway disease, and high levels of neutrophil proteases and eosinophil cationic protein (ECP) are found in sputum from patients with cystic fibrosis (CF). To investigate whether neutrophil proteases or CF sputum causes eosinophil degranulation, purified eosinophils from atopic asthmatic subjects were incubated for 2 h with neutrophil elastase, cathepsin G, and CF sputum, and the release of ECP was measured. We found that the percent release of ECP was higher after incubation with neutrophil elastase (10(-5) M) than with a buffer control [6.1 +/- 0.8 (SE) vs. 1.7 +/- 0.1%; P < 0.003] and represented >50% of the release caused by positive controls [Ca2+ ionophore A-23187 (5 x 10(-6) M) or serum-coated Sephadex beads]. The release of ECP after incubation with cathepsin G (2.3 +/- 0.2%) and CF sputum (6.2 +/- 2.0%) was also significantly higher than that with a buffer control (P < 0.05). Neutralization of free elastase activity with alpha1-proteinase inhibitor reduced the mean percent degranulation of eosinophils by neutrophil elastase by 50% (P = 0.0004) and by CF sputum by 75% (P = 0.02). Preincubation of eosinophils with cytochalasin B (10 mg/ml) and depletion of the incubation medium of Ca2+ also significantly attenuated degranulation of eosinophils incubated with purified free neutrophil elastase or CF sputum (P < 0.05). We conclude that neutrophil proteases, especially neutrophil elastase, and elastase-rich CF sputum cause degranulation of eosinophils in a mechanism partially dependent on Ca2+ and actin filaments.

Biomonitoring using accessible human cells for exposure and health risk assessment

A major goal for genetic toxicologist is to provide precise information on exposure and health risk assessment for effective prevention of health problems. A frequently used approach for population study has been to utilize readily available blood cells (lymphocytes and red blood cells) as sentinel cell types to detect biological effects from exposure and to provide early warning signals for health risk. However, such approach still cannot be used reliably for developing strategies in risk assessment and disease prevention. It is possible that other available cell types which are more representative of the target cells for disease may be used to overcome the deficiency. In this report, the use of non-blood cells for biomonitoring is briefly reviewed. Their usefulness in certain exposure condition is highlighted and their effectiveness in documenting exposure compared with other cell types such as the traditional blood cells is presented. It is obvious that the decision in using these non-blood cells in biomonitoring is based on the exposure condition and the experimental design. Nevertheless, monitoring studies using non-blood cells should be encouraged with emphasis on providing dose-response information, comparative response with other cell types and effectiveness for health risk assessment.

Effect of inhaled glucocorticoid on the cellular profile and cytokine levels in induced sputum from asthmatic patients

Cytokines are considered to play a role in the airway inflammation of bronchial asthma. We examined the cellular profile and cytokine levels in induced sputum samples obtained before and after treatment with beclomethasone dipropionate (BDP, 800 microg/day, for 4 weeks) in 12 mild to moderate asthmatic subjects who had not previously received inhaled glucocorticosteroids. Sputum was induced with a 20-min inhalation of 3% saline by an ultrasonic nebulizer. The freshly expectorated sputum separated from the saliva was analyzed for cell counts, for the concentration of interleukin-8 (IL-8), and for the concentration of granulocyte-macrophage colony-stimulating factor (GM-CSF). The mean percentage of eosinophils in the sputum samples decreased significantly after BDP treatment, but no significant change in the percentage of neutrophils was observed. The mean IL-8 and GM-CSF levels also decreased significantly after treatment. The BDP treatment was associated with an increase in the mean peak expiratory flow (PEF) and with a decrease in the diurnal variation of PEF. These results suggest that inhaled steroids improve airway inflammation and lung function in asthmatics, presumably in part by inhibiting the synthesis of inflammatory cytokines such as IL-8 and GM-CSF.

Sputum metalloproteinase-9/tissue inhibitor of metalloproteinase-1 ratio correlates with airflow obstruction in asthma and chronic bronchitis

Asthma and chronic bronchitis are inflammatory diseases with extracellular matrix (ECM) remodeling and collagen deposition. Collagen homeostasis is controlled by metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). We evaluated MMP and TIMP balance in induced sputum of 10 control, 31 untreated asthmatic, and 16 chronic bronchitic subjects. We first performed zymographic analysis to identify the profile of MMPs. Zymography revealed a similar MMPs profile in all populations studied and that MMP-9 was the major enzyme released. We then measured, using enzyme immunoassay, the concentrations of MMP-9 and of its inhibitor TIMP-1 and evaluated whether airflow limitation may be associated with an imbalance between these enzymes. MMP-9 and TIMP-1 concentrations were greater in sputum of patients with asthma and chronic bronchitis than in control subjects. The molar ratio between MMP-9 and TIMP-1 was lower in asthmatics and chronic bronchitics than in control subjects, and positively correlated with FEV1 values. In asthma, MMP-9 levels were significantly correlated with the number of macrophages and neutrophils. This study shows that airway inflammation in asthma and chronic bronchitis is associated with an imbalance between MMP-9 and TIMP-1 which may have a role in the pathogenesis of ECM remodeling and airflow obstruction.

Inflammatory response after inhalation of bacterial endotoxin assessed by the induced sputum technique

BACKGROUND

Organic dusts may cause inflammation in the airways. This study was performed to assess the usefulness of the induced sputum technique for evaluating the presence of airways inflammation using inhaled endotoxin (lipopolysaccharide) as the inducer of inflammation.

METHODS

To characterise the inflammatory response after inhalation of endotoxin, 21 healthy subjects inhaled 40 micrograms lipopolysaccharide and were examined before and 24 hours after exposure. Examinations consisted of a questionnaire for symptoms, spirometric testing, blood sampling, and collection of induced sputum using hypertonic saline. Eleven of the subjects inhaled hypertonic saline without endotoxin exposure as controls. Cell counts, eosinophilic cationic protein (ECP), and myeloperoxidase (MPO) were determined in blood and sputum.

RESULTS

A significantly higher proportion of subjects reported respiratory and general symptoms after endotoxin inhalation. MPO and the number of neutrophils in the blood were higher and spirometric values were decreased after the lipopolysaccharide challenge. In the sputum MPO, ECP, and the numbers of neutrophils and lymphocytes were higher after the lipopolysaccharide challenge. No significant differences were found after the inhalation of hypertonic saline compared with before, except for a significantly lower number of lymphocytes in the sputum.

CONCLUSIONS

The results support previous studies that inhaled endotoxin causes an inflammation at the exposure site itself, as well as general effects. Sampling of sputum seems to be a useful tool for assessing the presence of airways inflammation, and the inhalation of hypertonic saline used to induce sputum did not significantly interfere with the results found after inhalation of lipopolysaccharide.

Use of induced sputum to examine airway inflammation in childhood asthma

Airway inflammation is important in the pathogenesis of asthma, during which it may lead to symptomatic exacerbations and increases in asthma severity, as well as contribute to future decline in asthma status. The use of induced sputum has emerged as an important and useful technique to study airway inflammation. It has particular advantages in the study of childhood asthma because it is noninvasive and allows samples to be collected on repeated occasions in children over 7 years of age. The results of cell counts are reliable when the sputum is processed in a standardized manner involving selection from saliva, cell dispersion, and quantitative cytology. Children with asthma have increased eosinophils and mast cells, which may persist even with high doses of inhaled corticosteroid therapy. During a severe exacerbation of asthma, there is an intense and heterogeneous inflammatory response involving eosinophil and neutrophil accumulation and activation. Characterization of the relevance of airway inflammation in children with asthma is important.

Induced sputum and response to glucocorticoids

Jerry Dolovich has generated substantial new work that has had an international impact on the understanding and treatment of asthma and other airway diseases. For this, he is recognized as a Distinguished Clinician of the American Academy of Asthma, Allergy and Immunology. I have focused on some of his recent work with us using induced sputum to measure indices of airway inflammation noninvasively. The results illustrate that sputum eosinophilia (1) does not necessarily correlate with the severity of symptoms or severity of abnormalities of airway function, (2) does not always occur in exacerbations of asthma, and (3) may be a predictor clinical benefit to steroid treatment, which will be useful in practice. The observations imply that airway inflammation needs to be measured to understand the pathogenesis, pathophysiology, and treatment of asthma and other airway diseases.