Zoe Borrill

Exhaled breath condensate biomarkers in COPD

Biomarkers in chronic obstructive pulmonary disease may be useful in aiding diagnosis, defining specific phenotypes of disease, monitoring exacerbations and evaluating the effects of drugs. Exhaled breath condensate is a noninvasive means of sampling the airways, allowing biomarkers of airway inflammation and oxidative stress to be measured. In the present review, the use of exhaled breath condensate biomarkers in chronic obstructive pulmonary disease is explored and potential applications in diagnosis, disease phenotyping, exacerbation monitoring and clinical trials are considered. Exhaled breath condensate biomarkers are comprehensively reviewed in terms of method validation, reproducibility, disease specificity and sensitivity to detect changes in airway inflammation. The commonly used exhaled breath condensate methodologies in chronic obstructive pulmonary disease patients are shown to have considerable variability, due to technical issues concerning both sample collection and analysis. Despite these issues, there is still data to support the use of exhaled breath condensate biomarkers for monitoring chronic obstructive pulmonary disease exacerbations and the response to pharmacological intervention. Further improvements to sample collection and analysis methods will improve the sensitivity of these biomarkers. The use of cytokine arrays, mass spectrometry and nuclear magnetic resonance profiling of exhaled breath condensate has opened a new avenue for analysis, as hypothesis generation from such profiling may lead to further selection of biomarkers for specific analysis.

Reproducibility of exhaled breath condensate pH in chronic obstructive pulmonary disease

Increasingly, exhaled breath condensate (EBC) is being used to sample airway fluid from the lower respiratory tract. EBC pH may be a biomarker of airway inflammation in chronic obstructive pulmonary disease (COPD). In this study, the reproducibility of EBC pH in COPD was investigated. A total of 36 COPD patients and 12 healthy nonsmoking subjects participated in several investigations: duration of argon deaeration, within-sample variability, effect of freezing, leaving samples at room temperature, nose-peg use, within- (WD) and between-day (BD) variability. Analysis of repeated measurements was performed using the Bland–Altman method with limits of agreement (LOA; mean difference±2sd). Wider LOA indicate greater variability. EBC pH became significantly higher with argon deaeration for ≤5 min. Variability during sample analysis was minimal; LOA of within-sample variability, freezing for 3 months and leaving at room temperature for 3 h were −0.29–0.45, −0.37–0.42 and −0.13–0.09, respectively. In contrast, variability due to nose-peg use (LOA −1.46–1.99), WD (LOA −1.50–2.48) and BD variability (LOA −2.52–3.02) were higher in COPD. In healthy nonsmoking subjects, nose-peg use (LOA −0.27–0.23), WD (LOA −0.33–0.40) and BD variability (LOA −0.46–0.44) were more reproducible. In conclusion, the variability of exhaled breath condensate pH in chronic obstructive pulmonary disease patients is mainly due to changes in airway pH over time, which are not seen in healthy nonsmoking subjects. Reasons for these fluctuations in exhaled breath condensate pH are unclear and require further investigation.

A randomized, placebo-controlled study of the effects of the p38 MAPK inhibitor SB-681323 on blood biomarkers of inflammation in COPD patients

The p38 mitogen‐activated protein kinase (MAPK) signaling upregulates inflammation and is known to be increased in chronic obstructive pulmonary disease (COPD). The authors assessed the pharmacology of the novel p38 MAPK inhibitor SB‐681323 using blood biomarkers in COPD. Seventeen COPD patients (forced expiratory volume in 1 second 50%–80% predicted) using short‐acting bronchodilators participated in a double‐blind, double‐dummy, randomized, crossover study. Patients received single oral doses of SB‐681323 7.5 mg and 25 mg, prednisolone 10 mg and 30 mg, and placebo. Blood was obtained predose and at 1, 2, 6, and 24 hours postdose. Whole‐blood sorbitol‐induced phosphorylated (p) heat shock protein (HSP) 27 levels as a marker of p38 pathway activation and lipopolysaccharide‐induced tumor necrosis factor (TNF)–α production were assessed. Both doses of SB‐681323, but not prednisolone, significantly (P < .0001) reduced weighted mean (WM) pHSP27 (0–6 hours) by 58% compared with placebo. WM TNF‐α production (0–24 hours) was significantly reduced compared with placebo by SB‐681323 25 mg (40%, P = .005) and 7.5 mg (33.4%, P = .02), while prednisolone 30 mg and 10 mg caused 81.5% and 58.2% suppression, respectively (both P < .0001). SB‐681323 inhibited the p38 MAPK pathway to a greater degree than prednisolone did. SB‐681323 inhibited TNF‐α production. SB‐681323 is a potent p38 MAPK inhibitor that potentially suppresses inflammation in COPD.

The use of plethysmography and oscillometry to compare long‐acting bronchodilators in patients with COPD

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT Forced expiratory volume in 1 s (FEV(1)) is the standard measurement used to measure drug effects in chronic obstructive pulmonary disease (COPD) clinical trials. Having previously shown that specific airway conductance (sGaw) measured using body plethysmography and impulse oscillometry (IOS) are more sensitive than FEV(1) for assessing short-acting bronchodilator effects in patients with COPD, we conducted the first randomized, placebo-controlled study to compare long-acting bronchodilators in COPD patients using these techniques. WHAT THIS STUDY ADDS sGaw and IOS sensitively differentiated between the effects of tiotropium and salmeterol when FEV(1) measurements were similar. sGaw and IOS measurements are better than FEV(1) for sensitively assessing bronchodilator pharmacology and differentiating between treatments in COPD clinical trials. AIMS Assessment of bronchodilator pharmacology in chronic obstructive pulmonary disease (COPD) may be improved by using more sensitive methods than spirometry, such as impulse oscillometry (IOS) and body plethysmography. We sought to compare salmeterol (S) and tiotropium (Tio) using these methods. METHODS In this double-blind, randomized, four-way crossover study, 32 COPD patients received single doses of Tio (18 microg), S (50 and 100 microg) or placebo. Specific airway conductance (sGaw), forced expiratory volume in 1 s (FEV(1)) and IOS were measured pre- and up to 26 h postdose. Comparisons between treatments were analysed by weighted means (WM) between 0 and 12 (WM 0-12 h) and 12-24 h (WM 12-24 h) postdose. Data are expressed as mean difference (or geometric ratio for nonparametric data) with 95% confidence intervals. RESULTS Tio and S100 significantly improved FEV(1), sGaw and IOS parameters up to 26 h and S50 up to 16 h. WM analysis showed no difference between Tio and S100 in FEV(1) for 0-12 h or 12-24 h. Maximum mid-expiratory flow (-0.06; -0.11, -0.01) and R35 (0.02; 0.01, 0.03) demonstrated superiority of S100 compared with Tio for WM 0-12 h sGaw (1.12; 1.02, 1.23), R5 (-0.06; -0.09, -0.02), R15 (-0.03; -0.05, -0.01), and resonant frequency (RF) (-2.30; -3.83, -0.77) showed superiority of Tio compared with S100 for WM 12-24 h. At 26 h, sGaw, R5, R15, X5 and RF also showed superiority of Tio compared with S100. CONCLUSIONS sGaw and IOS parameters sensitively differentiated between the effects of Tio and S when FEV(1) measurements were similar. Clinical trials in patients with COPD should use IOS and sGaw to assess comprehensively bronchodilator pharmacology.

COPD phenotype description using principal components analysis

BackgroundAirway inflammation in COPD can be measured using biomarkers such as induced sputum and FeNO. This study set out to explore the heterogeneity of COPD using biomarkers of airway and systemic inflammation and pulmonary function by principal components analysis (PCA).Subjects and MethodsIn 127 COPD patients (mean FEV1 61%), pulmonary function, FeNO, plasma CRP and TNF-α, sputum differential cell counts and sputum IL8 (pg/ml) were measured. Principal components analysis as well as multivariate analysis was performed.ResultsPCA identified four main components (% variance): (1) sputum neutrophil cell count and supernatant IL8 and plasma TNF-α (20.2%), (2) Sputum eosinophils % and FeNO (18.2%), (3) Bronchodilator reversibility, FEV1 and IC (15.1%) and (4) CRP (11.4%). These results were confirmed by linear regression multivariate analyses which showed strong associations between the variables within components 1 and 2.ConclusionCOPD is a multi dimensional disease. Unrelated components of disease were identified, including neutrophilic airway inflammation which was associated with systemic inflammation, and sputum eosinophils which were related to increased FeNO. We confirm dissociation between airway inflammation and lung function in this cohort of patients.

The repeatability of interleukin-6, tumor necrosis factor-alpha, and C-reactive protein in COPD patients over one year.

Background Many of the systemic manifestations of chronic obstructive pulmonary disease (COPD) are mediated through increased systemic levels of inflammatory proteins. We assessed the long term repeatability of Interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and C-reactive protein (CRP) over one year and examined the relationships between these systemic markers in COPD. Methods Fifty-eight stable COPD patients completed a baseline and one-year visit. Serum IL-6, plasma CRP, and plasma TNF-α were measured. Repeatability was expressed by intraclass correlation coefficient (Ri) and the Bland–Altman method. Pearson correlations were used to determine the relationships between the systemic markers at both visits. Results There was moderate repeatability with a very high degree of statistical significance (p ≤ 0.001) between the two visits for all the systemic biomarkers (IL-6, CRP, and TNF-α). CRP was significantly associated with IL-6 at both visits (r = 0.55, p = 0.0001, r = 0.51, p = 0.0002, respectively). There were no other significant associations between the systemic markers at either of the visits. Conclusions Systemic inflammatory biomarkers IL-6, CRP, and TNF-α were moderately repeatable over a twelve month period in COPD patients. We have also shown that a robust and repeatable association between IL-6 and CRP exists.

Non-invasive biomarkers and pulmonary function in smokers.

Limited information exists regarding measurement, reproducibility and interrelationships of non-invasive biomarkers in smokers. We compared exhaled breath condensate (EBC) leukotriene B4 (LTB4) and 8-isoprostane, exhaled nitric oxide, induced sputum, spirometry, plethysmography, impulse oscillometry and methacholine reactivity in 18 smokers and 10 non-smokers. We assessed the relationships between these measurements and within-subject reproducibility of EBC biomarkers in smokers. Compared to non-smokers, smokers had significantly lower MMEF % predicted (mean 64.1 vs 77.7, p = 0.003), FEV1/FVC (mean 76.2 vs 79.8 p = 0.05), specific conductance (geometric mean 1.2 vs 1.6, p = 0.02), higher resonant frequency (mean 15.5 vs 9.9, p = 0.01) and higher EBC 8-isoprostane (geometric mean 49.9 vs 8.9 pg/ml p = 0.001). Median EBC pH values were similar, but a subgroup of smokers had airway acidification (pH < 7.2) not observed in non-smokers. Smokers had predominant sputum neutrophilia (mean 68.5%). Repeated EBC measurements showed no significant differences between group means, but Bland Altman analysis showed large individual variability. EBC 8-isoprostane correlated with EBC LTB4 (r = 0.78, p = 0.0001). Sputum supernatant IL-8 correlated with total neutrophil count per gram of sputum (r = 0.52, p = 0.04) and with EBC pH (r = −0.59, p = 0.02). In conclusion, smokers had evidence of small airway dysfunction, increased airway resistance, reduced lung compliance, airway neutrophilia and oxidative stress.

The effect of gas standardisation on exhaled breath condensate pH.

To the Editors: We have read with interest the American Thoracic Society/European Respiratory Society Task Force document on exhaled breath condensate (EBC) 1. EBC pH is emerging as a potential biomarker in respiratory disease. Gas standardisation (or de-aeration) of EBC with argon is commonly performed to remove carbon dioxide prior to pH measurement 2–4. It has been argued that CO2 is unwelcome “noise” in the sample and, although the completeness of CO2 removal has not been confirmed, gas-standardised EBC pH is stable and provides reproducible measurements 3, 4. However, some authors regard CO2 as a relevant component of EBC and have measured pH without gas standardisation 5, 6. These variations in methodology make comparison between studies difficult. We recently reported a mean change in pH after gas standardisation of 0.94 4, and this pH was stable at room temperature. Despite …

Comparison of the effects of salmeterol/fluticasone propionate with fluticasone propionate on airway physiology in adults with mild persistent asthma

BackgroundThis study compared the effect of inhaled fluticasone propionate (FP) with the combination of salmeterol/fluticasone propionate (SFC) on lung function parameters in patients with mild asthma.MethodsAdult patients with mild persistent asthma (≥ 80% predicted FEV1) receiving 200–500 μg of BDP or equivalent were randomised to receive either FP 100 μg or SFC 50/100 μg twice daily from a Diskus® inhaler for four weeks. The primary outcome was the change from baseline in airway resistance (sRaw) at 12 hrs post dose measured by whole body plethysmography. Impulse oscillometry and spirometry were also performed.ResultsA comparison of the geometric mean sRaw at 12 hrs post dose in the SFC group to the FP group gave a ratio of 0.76 (0.66 – 0.89, p < 0.001) at week 2 and 0.81 (0.71 – 0.94, p = 0.006) at week 4. Similarly, significant results in favour of SFC for oscillometry measurements of resistance and reactance were observed. FEV1 was also significantly superior at week 2 in the SFC group (mean difference 0.16L, 95% CI; 0.03 – 0.28, p = 0.015), but not at week 4 (mean difference 0.17L, 95% CI -0.01 – 0.34, p = 0.060).ConclusionSFC is superior to FP in reducing airway resistance in mild asthmatics with near normal FEV1 values. This study provides evidence that changes in pulmonary function in patients with mild asthma are detected more sensitively by plethysmography compared to spirometryTrial registration numberNCT00370591.

Tolerability of high cumulative doses of the HFA modulite beclomethasone dipropionate/formoterol combination inhaler in asthmatic patients

The corticosteroid beclomethasone dipropionate (BDP) has been formulated with the long acting beta agonist formoterol (BDP/formoterol 100 microg/6 microg, Foster) in a single inhaler using Modulite technology. We have investigated the acute tolerability of high, cumulative doses of BDP/formoterol compared to formoterol alone and placebo. This was a double blind, 3-way cross-over comparison of 10 puffs of BDP/formoterol 100 microg/6 microg or formoterol 6 microg or placebo during maintenance treatment with BDP/formoterol two puffs per day. Pharmacokinetics over 12h during maintenance treatment was measured on day 7. High cumulative doses were then administered on three separated days. Eighteen patients with asthma were recruited (mean FEV(1) 65% predicted). The primary endpoint was serum potassium over the 12h period after high doses. QTc, blood pressure and heart rate over 12h, and plasma lactate and glucose over 3h following dosing were assessed. Formoterol caused a significantly greater decrease in serum potassium than BDP/formoterol or placebo (difference in mean minimum concentrations; 0.11 and -0.15 mmol/l, respectively, p<0.05 for both comparisons). No significant differences in serum potassium parameters were found between BDP/formoterol and placebo. QTc, plasma lactate and vital signs values observed with the combination were not statistically different from those with formoterol alone. For glucose, the mean maximum increase after formoterol treatment was 0.4 mmol/l (p<0.01 compared to placebo), while BDP/formoterol treatment caused a maximum increase of 0.7 mmol/l (p<0.01 compared to formoterol and placebo). The active metabolite of BDP is beclomethasone-17-monopropriate (B17MP), which reached Cmax at 0.25 h, with an elimination half-life of 3.7 h. Formoterol also reached Cmax at 0.25 h, and concentrations were measurable up to 12 h. High doses of BDP/formoterol did not significantly reduce serum potassium, while formoterol alone did to a greater extent. The BDP/formoterol combination was well tolerated, and exhibited a safety profile generally similar to formoterol alone when administered in high doses to stable asthmatic patients.