Peter J. Sterk

Effect of inhaled steroids on airway hyperresponsiveness, sputum eosinophils, and exhaled nitric oxide levels in patients with asthma

BACKGROUND Airway hyperresponsiveness, induced sputum eosinophils, and exhaled nitric oxide (NO) levels have all been proposed as non-invasive markers for monitoring airway inflammation in patients with asthma. The aim of this study was to compare the changes in each of these markers following treatment with inhaled glucocorticosteroids in a single study. METHODS In a randomised, double blind, placebo controlled, parallel study 25 patients with mild asthma (19–34 years, forced expiratory volume in one second (FEV1) >75% predicted, concentration of histamine provoking a fall in FEV1 of 20% or more (PC20) <4u2009mg/ml) inhaled fluticasone propionate (500u2009μg twice daily) for four weeks. PC20 to histamine, sputum eosinophil numbers, and exhaled NO levels were determined at weeks 0, 2, and 4, and two weeks after completing treatment. Sputum was induced by inhalation of hypertonic (4.5%) saline and eosinophil counts were expressed as percentage non-squamous cells. Exhaled NO levels (ppb) were measured by chemiluminescence. RESULTS In the steroid treated group there was a significant increase in PC20, decrease in sputum eosinophils, and decrease in exhaled NO levels compared with baseline at weeks 2 and 4 of treatment. Subsequently, each of these variables showed significant worsening during the two week washout period compared with week 4. These changes were significantly different from those in the placebo group, except for the changes in sputum eosinophils and exhaled NO levels during the washout period. There were no significant correlations between the changes in the three markers in either group at any time. CONCLUSIONS Treatment of asthmatic subjects with inhaled steroids for four weeks leads to improvements in airway hyperresponsiveness to histamine, eosinophil counts in induced sputum, and exhaled nitric oxide levels. The results suggest that these markers may provide different information when monitoring anti-inflammatory treatment in asthma.

Effect of experimental rhinovirus 16 colds on airway hyperresponsiveness to histamine and interleukin‐8 in nasal lavage in asthmatic subjects in vivo

Background Asthma exacerbations are closely associated with respiratory virus infections. However, the pathophysiological consequences of such infections in asthma are largely unclear.

Relation between duration of smoking cessation and bronchial inflammation in COPD

Background: Chronic obstructive pulmonary disease (COPD) is associated with airway inflammation. Although smoking cessation improves symptoms and the decline in lung function in COPD, it is unknown whether bronchial inflammation in patients with established COPD varies with the duration of smoking cessation. Methods: 114 patients (99 men) with COPD of mean (SD) age 62 (8) years, a median (IQR) smoking history of 42 (31–55) pack years, no inhaled or oral corticosteroids, all current or ex-smokers (nu200a=u200a42, quit >1 month, median cessation duration 3.5 years), post-bronchodilator FEV1 63 (9)% predicted, and FEV1/IVC 48 (9)% were studied cross sectionally. The numbers of subepithelial T lymphocytes (CD3, CD4, CD8), neutrophils, macrophages, eosinophils, mast cells, and plasma cells were measured in bronchial biopsy specimens (median (IQR)/0.1 mm2) using fully automated image analysis. Results: Ex-smokers with COPD had higher CD3+, CD4+, and plasma cell numbers than current smokers with COPD (149 (88–225) v 108 (61–164), pu200a=u200a0.036; 58 (32–90) v 40 (25–66), pu200a=u200a0.023; and 9.0 (5.5–20) v 7.5 (3.1–14), pu200a=u200a0.044, respectively), but no difference in other inflammatory cells. Short term ex-smokers (<3.5 years) had higher CD4+ and CD8+ cell numbers than current smokers (pu200a=u200a0.017, pu200a=u200a0.023; respectively). Conversely, long term ex-smokers (quit ⩾3.5 years) had lower CD8+ cell numbers than short term ex-smokers (pu200a=u200a0.009), lower CD8/CD3 ratios than both current smokers and short-term ex-smokers (pu200a=u200a0.012, pu200a=u200a0.003; respectively), and higher plasma cell numbers than current smokers (pu200a=u200a0.003). Conclusions: With longer duration of smoking cessation, CD8 cell numbers decrease and plasma cell numbers increase. This indicates that bronchial T lymphocyte and plasma cell counts, but not other inflammatory cells, are related to duration of smoking cessation in patients with COPD.

Benefits of high altitude allergen avoidance in atopic adolescents with moderate to severe asthma, over and above treatment with high dose inhaled steroids

Some patients with severe asthma cannot be controlled with high doses of inhaled steroids (ICS), which may be related to ongoing environmental allergen exposure.

Assessing the effect of deep inhalation on airway calibre: a novel approach to lung function in bronchial asthma and COPD

Bronchoconstriction in bronchial asthma and chronic obstructive pulmonary disease (COPD) may be due to decreased airway calibre and/or to the inability of the airways to distend after a deep inhalation (DI). The purpose of this review is to discuss the physiological and clinical relevance of this latter mechanism. During induced constriction, DI shows remarkable bronchodilatation in normal subjects, but a blunted or null effect in asthmatics. In contrast, during spontaneous bronchospasm DI tends to decrease airway calibre. From a functional point of view, airway inflammation, remodelling, and peripheral bronchoconstriction could prevent airway smooth muscle from stretching. Therapeutic intervention improving lung function may change the response to DI. For example, bronchodilators allow expiratory airflow before DI to increase more than after DI, because of decreased bronchial hysteresis. This suggest that bronchodilation might be systematically underestimated from parameters derived from maximal expiratory manoeuvres. Inhaled corticosteroids tend to increase the dilator effect of DI, likely due to decreased bronchial and peribronchial oedema. In conclusion, measuring the effects of deep inhalation on lung function is an easy and simple test able to evaluate the structural changes occurring in the airways and to monitor the effectiveness of therapy.

Enhanced Bronchial Expression of Extracellular Matrix Proteins in Chronic Obstructive Pulmonary Disease

Remodeling of airways and blood vessels is an important feature in chronic obstructive pulmonary disease (COPD). By using immunohistochemical analysis, we examined bronchial expression patterns of various extracellular matrix (ECM) components such as collagens (subtypes I, III, and IV), fibronectin, and laminin beta2 in patients with COPD (forced expiratory volume in 1 second [FEV1] <or=75%; n = 15) and without COPD (FEV1 >or=85%; n = 16) and correlated expression data with lung function. Quantitative analysis revealed enhanced levels (P < .01) of total collagens I, III, and IV in surface epithelial basement membrane (SEBM) and collagens I and III in bronchial lamina propria (P < .02) and adventitia (P < .05) in COPD. Distinct and increased (P < .05) vascular expression of fibronectin accounts for intimal vascular fibrosis, whereas laminin beta2 (P < .05) was elevated in airway smooth muscle (ASM). FEV1 values inversely correlated with collagens in the SEBM, fibronectin in bronchial vessels, and laminin in the ASM. Our data suggest that COPD exhibits increased bronchial deposition of ECM proteins that contribute to deteriorated lung function and airway remodeling.

Exhaled air molecular profiling in relation to inflammatory subtype and activity in COPD

Eosinophilic inflammation in chronic obstructive pulmonary disease (COPD) is predictive for responses to inhaled steroids. We hypothesised that the inflammatory subtype in mild and moderate COPD can be assessed by exhaled breath metabolomics. Exhaled compounds were analysed using gas chromatography and mass spectrometry (GC-MS) and electronic nose (eNose) in 28 COPD patients (12/16 Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage I/II, respectively). Differential cell counts, eosinophil cationic protein (ECP) and myeloperoxidase (MPO) were measured in induced sputum. Relationships between exhaled compounds, eNose breathprints and sputum inflammatory markers were analysed and receiver operating characteristic (ROC) curves were constructed. Exhaled compounds were highly associated with sputum cell counts (eight compounds with eosinophils, 17 with neutrophils; p<0.01). Only one compound (alkylated benzene) overlapped between eosinophilic and neutrophilic profiles. GC-MS and eNose breathprints were associated with markers of inflammatory activity in GOLD stage I (ECP: 19 compounds, p<0.01; eNose breathprint r=0.84, p=0.002) (MPO: four compounds, p<0.01; eNose r=0.72, p=0.008). ROC analysis for eNose showed high sensitivity and specificity for inflammatory activity in mild COPD (ECP: area under the curve (AUC) 1.00; MPO: AUC 0.96) but not for moderate COPD. Exhaled molecular profiles are closely associated with the type of inflammatory cell and their activation status in mild and moderate COPD. This suggests that breath analysis may be used for assessment and monitoring of airway inflammation in COPD.

Exhaled nitric oxide predicts lung function decline in difficult-to-treat asthma.

A subset of patients with asthma is known to have progressive loss of lung function despite treatment with corticosteroids. The aim of the present study was to identify risk factors of decline in forced expiratory volume in one second (FEV1) in patients with difficult-to-treat asthma. In total, 136 nonsmoking patients with difficult-to-treat asthma were recruited between 1998 and 1999. Follow-up assessment was performed 5–6u2005yrs later in 98 patients. The predictive effect of clinical characteristics and inflammatory markers were analysed at baseline (asthma onset and duration, atopy, airway hyperresponsiveness, blood and sputum eosinophils, and the fraction of nitric oxide in exhaled air (FeNO)) on subsequent decline in post-bronchodilator FEV1. Patients with high FeNO (≥20u2005ppb) had an excess decline of 40.3 (95% confidence interval (CI) 7.3–73.2)u2005mL·yr−1 compared to patients with low FeNO. FeNO ≥20u2005ppb was associated with a relative risk of 1.9 (95% CI, 1.1–2.6) of having an accelerated (≥25u2005mL·yr−1) decline in FEV1. In patients with baseline FEV1 ≥80% of predicted, this relationship was even stronger: 90 versus 29% had accelerated decline in FEV1 (FeNO ≥20u2005ppb versus FeNO <20u2005ppb respectively; relative risk 3.1 (95% CI, 1.7–3.4). Exhaled nitric oxide is a predictor of accelerated decline in lung function in patients with difficult-to-treat asthma, particularly if forced expiratory volume in one second is still normal.

Small airways function and molecular markers in exhaled air in mild asthma

Background: Several studies suggest that the periphery of the lung is the major site of inflammation in asthma. Fractional exhaled nitric oxide (Feno) and 8-isoprostane have been proposed as biomarkers of inflammation and oxidative stress. We therefore hypothesised that small airway dysfunction in asthma is of inflammatory origin that can be detected by molecular markers in exhaled air. To test this hypothesis, we examined the relationship of Feno and 8-isoprostane in exhaled air with small airways function as assessed by the single breath nitrogen test. Methods: Sixteen patients (14 women) with mild atopic asthma (forced expiratory volume in 1 second >80% predicted) of mean (SD) age 23.0 (5.5) years participated in a cross sectional study. Feno was recorded by chemiluminescence and 8-isoprostane was measured by ELISA in concentrated exhaled breath condensate. The slope of phase III (δN2) and the closing volume (CV) were assessed from the single breath washout curve. Results: The median Feno level was 30.4 ppb (range 10.1–82.8), the median 8-isoprostane concentration in exhaled breath condensate was 2.2 pg/ml (range 1.6–2.7), and the mean (SD) δN2 value was 1.1 (0.4)% N2/l. Feno was positively associated with δN2 (rsu200a=u200a0.54, pu200a=u200a0.032) while 8-isoprostane was inversely correlated with FEV1% predicted (rsu200a=u200a−0.58; pu200a=u200a0.017) and CV as a percentage of vital capacity (rsu200a=u200a0.58; pu200a=u200a0.019). Conclusions: Feno and 8-isoprostane in exhaled air are associated with small airways function in mild asthma. This suggests that these markers reflect small airway inflammation and favours a role for them as disease markers that is complementary to spirometry in the monitoring of patients with asthma.

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.