Contrasting effects of ATP and adenosine on capsaicin challenge in asthmatic patients.

BACKGROUND: Adenosine 5'-triphosphate (ATP) stimulates pulmonary vagal slow conducting C-fibres and fast conducting Aδ-fibres with rapidly adapting receptors (RARs). Pulmonary C-fibres but not RARs are also sensitive to capsaicin, a potent tussigenic agent in humans. Thus, the aim of this study was to determine the effects of ATP and its metabolite adenosine (given as adenosine 5'-monophosphate, AMP) on capsaicin challenge in asthmatic patients. METHODS: Cough (quantified as visual analogue scale, VAS), dyspnoea (quantified as Borg score), and FEV1 were quantified following bronchoprovocation using capsaicin, adenosine and ATP in healthy non-smokers (age 40±4y, 6 males), smokers (45±4y, 5 males) and asthmatic patients (37±3y, 5 males); n = 10 in each group. RESULTS: None of the healthy non-smokers responded to either AMP or ATP. AMP induced bronchoconstriction in one smoker and eight asthmatics, and ATP in two smokers and all ten asthmatics. The geometric mean of capsaicin causing ≥5 coughs (C5) increased from 134 to 203 µM in non-smokers and from 117 to 287 µM in asthmatics after AMP, whereas it decreased from 203 to 165 µM and 125 to 88 µM, respectively after ATP. AMP decreased C5 from 58 to 29 µM and ATP increased from 33 to 47 µM in smokers. However, due to intergroup variability, these effects of ATP and AMP were not statistically significant (0.125 ≤ p ≤ 0.998). That notwithstanding, in healthy and asthmatic subjects the effects of the ATP showed a tendency to be greater than those of AMP (p < 0.053). Dyspnea, assessed by Borg score, increased after ATP (p < 0.001) and AMP (p < 0.001) only in asthmatic patients. Intensity of cough assessed by VAS increased (p < 0.05) after second capsaicin challenges performed after AMP in all groups, but not after ATP. CONCLUSIONS: Asthmatic patients exhibit hypersensitivity to aerosolized AMP and ATP, but aerosolized AMP does not mimic the effects of ATP and the effects of ATP are not mediated by adenosine.

Effects of Aerosolized Adenosine 5'-Triphosphate in Smokers and Patients With COPD.

BACKGROUND: Extracellular adenosine 5'-triphosphate (ATP) stimulates vagal C and Aδ fibers in the lung, resulting in pronounced bronchoconstriction and cough mediated by P2X2/3 receptors located on vagal sensory nerve terminals. We investigated the effects of nebulized ATP on cough and symptoms in control subjects, healthy smokers, and patients with COPD and compared these responses to the effects of inhaled adenosine, the metabolite of ATP. METHODS: We studied the effects of inhaled ATP and adenosine monophosphate (AMP) on airway caliber, perception of dyspnea assessed by the Borg score, cough sensitivity, and ATP in exhaled breath condensate in healthy nonsmokers (n = 10), healthy smokers (n = 14), and patients with COPD (n = 7). RESULTS: In comparison with healthy subjects, ATP induced more dyspnea, cough, and throat irritation in smokers and patients with COPD, and the effects of ATP were more pronounced than those of AMP. The concentration of ATP in the exhaled breath condensate of patients with COPD was elevated compared with that of healthy subjects. CONCLUSIONS: Smokers and patients with COPD manifest hypersensitivity to extracellular ATP, which may play a mechanistic role in COPD.

A novel approach to partition central and peripheral airway nitric oxide.

BACKGROUND: Determining the site of airways inflammation may lead to the targeting of therapy. Nitric oxide (NO) is a biomarker of airway inflammation and can be measured at multiple exhalation flow rates to allow partitioning into bronchial (large/central airway maximal nitric oxide flux [J'awno]) and peripheral (peripheral/small airway/alveolar nitric oxide concentration [Cano]) airway contributions by linear regression. This requires a minimum of three exhalations. We developed a simple and practical method to partition NO. METHODS: In 29 healthy subjects (FEV1, 97% ± 3% predicted), 13 patients with asthma (FEV1, 90% ± 4% predicted), 14 patients with COPD (FEV1, 59% ± 3% predicted), and 12 patients with cystic fibrosis (CF) (FEV1, 60% ± 3% predicted), we measured the area under the curve of the NO concentration/exhalation time plot (AUC-NO) at exhalation flow rates of 50, 100, 200, and 300 mL/s. We determined the change of the total AUC-NO production (ΔAUC-NO) among the four different exhalation flow rates and compared these levels to Cano and J'awno indices measured conventionally by linear regression. RESULTS: The change in AUC-NO between increasing exhalation flow rates of 50 to 200 mL/s (ΔAUC-NO50-200) was strongly correlated with J'awno in all patient groups as follows: healthy subjects (r = 0.94, P < .001), patients with asthma (r = 0.98, P < .001), patients with COPD (r = 0.93, P < .001), and patients with CF (r = 0.74, P < .05). In all subjects, AUC-NO at an exhalation flow rate of 200 mL/s (AUC-NO200) correlated with Cano (r = 0.69, P < .01). CONCLUSIONS: The bronchial production of NO can be determined by measuring ΔAUC-NO50-200, whereas AUC-NO200 measures its peripheral concentration. This approach is simple, quick, and does not require sophisticated equipment or mathematical models.

Standardised exhaled breath collection for the measurement of exhaled volatile organic compounds by proton transfer reaction mass spectrometry.

BACKGROUND: Exhaled breath volatile organic compound (VOC) analysis for airway disease monitoring is promising. However, contrary to nitric oxide the method for exhaled breath collection has not yet been standardized and the effects of expiratory flow and breath-hold have not been sufficiently studied. These manoeuvres may also reveal the origin of exhaled compounds. METHODS: 15 healthy volunteers (34 ± 7 years) participated in the study. Subjects inhaled through their nose and exhaled immediately at two different flows (5 L/min and 10 L/min) into methylated polyethylene bags. In addition, the effect of a 20 s breath-hold following inhalation to total lung capacity was studied. The samples were analyzed for ethanol and acetone levels immediately using proton-transfer-reaction mass-spectrometer (PTR-MS, Logan Research, UK). RESULTS: Ethanol levels were negatively affected by expiratory flow rate (232.70 ± 33.50 ppb vs. 202.30 ± 27.28 ppb at 5 L/min and 10 L/min, respectively, p < 0.05), but remained unchanged following the breath hold (242.50 ± 34.53 vs. 237.90 ± 35.86 ppb, without and with breath hold, respectively, p = 0.11). On the contrary, acetone levels were increased following breath hold (1.50 ± 0.18 ppm) compared to the baseline levels (1.38 ± 0.15 ppm), but were not affected by expiratory flow (1.40 ± 0.14 ppm vs. 1.49 ± 0.14 ppm, 5 L/min vs. 10 L/min, respectively, p = 0.14). The diet had no significant effects on the gasses levels which showed good inter and intra session reproducibility. CONCLUSIONS: Exhalation parameters such as expiratory flow and breath-hold may affect VOC levels significantly; therefore standardisation of exhaled VOC measurements is mandatory. Our preliminary results suggest a different origin in the respiratory tract for these two gasses.

Inflammatory markers: exhaled nitric oxide and carbon monoxide during the ovarian cycle.

Nitric oxide (NO) production and carbon monoxide (CO) production are increased in inflammatory lung diseases. Although there are some pieces of evidence for hormonal modulation by estrogen, little is known about exhaled NO and CO during the ovarian cycle. In 23 subjects, we measured exhaled NO and CO by an online analyzer. Significantly higher levels of exhaled NO were found at the midcycle compared with those in the premenstrual period or during menstruation. Higher levels of CO were after ovulation and reached a peak in the premenstrual phase. The lowest levels of CO were observed in the first days of the estrogen phase. In males, there was no significant variation in exhaled NO and CO. Exhaled NO and CO levels vary during the ovarian cycle in women, and this fact should be taken into account during serial measurements of these markers in the female population.

Comparison of Symbicort® versus Pulmicort® on steroid pharmacodynamic markers in asthma patients.

BACKGROUND: Combination therapy with inhaled corticosteroids (ICS) and long-acting ß(2)-adrenergic agonists (LABA) is reported to have superior effects on controlling asthma symptoms to ICS alone; however, there is no molecular-based evidence to explain the clinical effects. Here, the effect of the ICS/LABA combination was compared with ICS on glucocorticoid receptor (GR) activation in sputum macrophages. METHODS: In a randomised, double-blind cross-over placebo-controlled 6-visit study, 10 patients with mild asthma were given placebo, formoterol (Oxis(®) 12 µg), budesonide (Pulmicort(®) 200 µg :BUD200, or 800 µg :BUD800), or budesonide/formoterol combination (Symbicort(®)) as a single 100/6 µg (SYM100) or double 200/12 µg (SYM200) dose. Sputum macrophages were separated by plate adhesion from induced sputum. GR binding to the glucocorticoid-response elements on oligonucleotides (GR-GRE binding) was evaluated by ELISA. mRNA expression of MAP-kinase phosphatase (MKP)-1 and IL-8 were measured by quantitative RT-PCR. RESULTS: GR-GRE binding was significantly increased after treatment with SYM100 (3.5 OD/10 µg protein, median, p < 0.05) versus placebo (1.3) and BUD200 (1.6), and the induction was higher than that of BUD800 (2.4). MKP-1 mRNA was increased and IL-8 mRNA was significantly inhibited by BUD800, SYM100 and SYM200 versus placebo. CONCLUSIONS: The effects of SYM100 and SYM200 on GR activation were not different from that of BUD800 and superior to BUD200. Thus, it has been confirmed at a molecular level that inhaled combination therapy with a lower dose of budesonide has an equivalent effect to a high dose of budesonide alone. In addition, GR-GRE binding is found to be a valuable pharmacodynamic marker for steroid efficacy in clinical studies.

Assessment of reproducibility of exhaled hydrogen peroxide concentration and the effect of breathing pattern in healthy subjects.

BACKGROUND: Hydrogen peroxide (H2O2) is detectable in exhaled breath condensate (EBC) and has been proposed to be a surrogate marker of oxidative stress in the airways. In this study we tested whether the breathing pattern during EBC collection influences the concentration of exhaled H2O2. METHODS: EBC was collected during (1) tidal breathing and (2) breathing with increased tidal volume for 10 min from 16 healthy volunteers. On-line H2O2 measurement was performed by the EcoCheck™ biosensor system. Repeated measurements were also conducted to assess intrasubject reproducibility. RESULTS: Minute ventilation, tidal volume, expiratory flow rate were all increased significantly when subjects were asked to perform breathing with increased tidal volume. In parallel, EBC volume increased (1413±59 vs. 1959±71 µL, p<0.001), whereas exhaled H2O2 levels decreased significantly (1400±170 vs. 840±130 nmol/L, p<0.001). H2O2 levels did not correlate with any individual breathing parameters (p>0.05). Assessment of intersubject variability of H2O2 measurements during the two types of breathing revealed a coefficient of variation of 49 and 54%, respectively. The EBC H2O2 measurement was highly reproducible (888±176 vs. 874±156 nmol/L) as tested during normal breathing. CONCLUSIONS: These data demonstrate that the concentration of H2O2 in EBC depends on the ventilatory pattern during sample collection that has to be taken into consideration in all EBC H2O2 assays.

Osteoprotegerin in sputum is a potential biomarker in COPD.

BACKGROUND: COPD is characterized by chronic airflow limitation and inflammation of the respiratory tract. Several inflammatory biomarkers have been evaluated in COPD but are poorly related to disease severity and progression. Osteoprotegerin (OPG) is a glycoprotein mediator that is expressed in the lung and macrophages, so we have studied its concentration in induced sputum and macrophages of patients with COPD. METHODS: OPG was measured by enzyme-linked immunosorbent assay in induced sputum of patients with COPD and control subjects. RESULTS: OPG concentrations in induced sputum of patients with COPD (18.7 ± 18.6 ng/mL, n = 39) were significantly higher than those of healthy smokers (8.1 ± 5.6 ng/mL, n = 15), healthy nonsmokers (3.5 ± 3.8 ng/mL, n = 14), or patients with asthma (8.0 ± 5.4 ng/mL, n = 18). Sputum OPG levels in COPD negatively correlated with FEV(1) and positively correlated with residual volume to total lung capacity ratio (RV/TLC) (r = 0.55, P < .05), transfer factor of the lung for carbon monoxide (r = -0.53, P < .05), and carbon monoxide transfer coefficient (r = -0.61, P < .01). By contrast, sputum IL-8 concentrations were related to disease severity but not to RV/TLC or gas diffusion. Airway macrophages and neutrophils were positive for OPG by immunocytochemistry in sputum and peripheral lung tissue. OPG induced matrix metalloproteinase-9 release from sputum macrophages in vitro. CONCLUSIONS: Sputum OPG may be a useful biomarker to monitor parenchymal destruction in COPD.

Nitric oxide synthase isoenzyme expression and activity in peripheral lung tissue of patients with chronic obstructive pulmonary disease.

RATIONALE: Nitric oxide (NO) is increased in the lung periphery of patients with chronic obstructive pulmonary disease (COPD). However, expression of the NO synthase(s) responsible for elevated NO has not been identified in the peripheral lung tissue of patients with COPD of varying severity. METHODS: Protein and mRNA expression of nitric oxide synthase type I (neuronal NOS [nNOS]), type II (inducible NOS [iNOS]), and type III (endothelial NOS [eNOS]) were quantified by Western blotting and reverse transcription-polymerase chain reaction, respectively, in specimens of surgically resected lung tissue from nonsmoker control subjects, patients with COPD of varying severity, and smokers without COPD, and in a lung epithelial cell line (A549). The effects of nitrative/oxidative stress on NOS expression and activity were also evaluated in vitro in A549 cells. nNOS nitration was quantified by immunoprecipitation and dimerization of nNOS was detected by low-temperature SDS-PAGE/Western blot in the presence of the peroxynitrite generator, 3-morpholinosydnonimine-N-ethylcarbamide (SIN1), in vitro and in vivo. MEASUREMENTS AND MAIN RESULTS: Lung tissue from patients with severe and very severe COPD had graded increases in nNOS (mRNA and protein) compared with nonsmokers and normal smokers. Hydrogen peroxide (H(2)O(2)) and SIN1 as well as the cytokine mixture (IFN-gamma, IL-1beta, and tumor necrosis factor-alpha) increased mRNA expression and activity of nNOS in A549 cells in a concentration-dependent manner compared with nontreated cells. Tyrosine nitration resulted in an increase in nNOS activity in vitro, but did not affect its dimerization. CONCLUSIONS: Patients with COPD have a significant increase in nNOS expression and activity that reflects the severity of the disease and may be secondary to oxidative stress.

A protein deacetylase SIRT1 is a negative regulator of metalloproteinase-9.

Inappropriate elevation of matrix metalloproteinase-9 (MMP9) is reported to be involved in the pathogenesis of chronic obstructive pulmonary disease (COPD). The object of this study was to identify the molecular mechanism underlying this increase of MMP9 expression, and here we show that oxidative stress-dependent reduction of a protein deacetylase, SIRT1, known as a putative antiaging enzyme, causes elevation of MMP9 expression. A sirtuin inhibitor, splitomycin, and SIRT1 knockdown by RNA interference led an increase in MMP9 expression in human monocytic U937 cells and in primary sputum macrophages, which was detected by RT-PCR, Western blot, activity assay, and zymography. In fact, the SIRT1 level was significantly decreased in peripheral lungs of patients with COPD, and this increase was inversely correlated with MMP9 expression and MMP9 promoter activation detected by a chromatin immunoprecipitation assay. H(2)O(2) reduced SIRT1 expression and activity in U937 cells; furthermore, cigarette smoke exposure also caused reduction of SIRT1 expression in lung tissue of A/J mice, with concomitant elevation of MMP9. Intranasal treatment of a selective and novel SIRT1 small molecule activator, SRT2172, blocked the increase of MMP9 expression in the lung as well as pulmonary neutrophilia and the reduction in exercise tolerance. Thus, SIRT1 is a negative regulator of MMP9 expression, and SIRT1 activation is implicated as a novel therapeutic approach to treating chronic inflammatory diseases, in which MMP9 is abundant.

Peroxynitrite elevation in exhaled breath condensate of COPD and its inhibition by fudosteine.

BACKGROUND: Peroxynitrite (PN) formed by the reaction of nitric oxide and superoxide is a powerful oxidant/nitrosant. Nitrative stress is implicated in COPD pathogenesis, but PN has not been detected due to a short half-life (< 1 s) at physiologic condition. Instead, 3-nitrotyrosine has been measured as a footprint of PN release. METHOD: PN was measured using oxidation of 2',7'-dichlorofluorescein (DCDHF) in exhaled breath condensate (EBC) collected in high pH and sputum cells. The PN scavenging effect was also evaluated by the same system as PN-induced bovine serum albumin (BSA) nitration. RESULTS: The mean (+/- SD) PN levels in EBC of COPD patients (7.9 +/- 3.0 nmol/L; n = 10) were significantly higher than those of healthy volunteers (2.0 +/- 1.1 nmol/L; p < 0.0001; n = 8) and smokers (2.8 +/- 0.9 nmol/L; p = 0.0017; n = 6). There was a good correlation between PN level and disease severity (FEV(1)) in COPD (p = 0.0016). Fudosteine (FDS), a unique mucolytic antioxidant, showed a stronger scavenging effect of PN than N-acetyl-cysteine on DCDHF oxidation in vitro and in sputum macrophages, and also on PN-induced BSA nitration. FDS (0.1 mmol/L) reduced PN-enhanced interleukin (IL)-1beta-induced IL-8 release and restored corticosteroid sensitivity defected by PN more potently than those induced by H(2)O(2) in A549 airway epithelial cells. CONCLUSION: This noninvasive PN measurement in EBC may be useful for monitoring airway nitrative stress in COPD. Furthermore, FDS has the potential to inhibit PN-induced events in lung by its scavenging effect.

Effects of aminoguanidine, an inhibitor of inducible nitric oxide synthase, on nitric oxide production and its metabolites in healthy control subjects, healthy smokers, and COPD patients.

BACKGROUND: Nitric oxide (NO) is produced by resident and inflammatory cells in the respiratory tract by the enzyme NO synthase (NOS), which exists in three isoforms: neuronal NOS (nNOS), inducible NOS (iNOS), and endothelial NOS. NO production is increased in patients with COPD, and the production of NO under oxidative stress conditions generates reactive nitrogen species that may amplify the inflammatory response in COPD. METHODS: To examine the role of increased NO in COPD, we administered a relatively selective iNOS inhibitor, aminoguanidine, by nebulization in a double-blind, placebo-controlled study in COPD patients, healthy smokers, and healthy nonsmoking subjects. We investigated whether aminoguanidine had any effect on exhaled NO produced in the central lung (flux of NO from the airways [Jno] and peripheral lungs (concentration of NO in peripheral lung [Calv], on NO metabolites (nitrite [NO(2)(-)]/nitrate [NO(3)(-)], peroxinitrite [ONOO(-)], nitrotyrosine), and on a marker of oxidative stress (8-isoprostane) in exhaled breath condensate (EBC) and in sputum. RESULTS: Aminoguanidine administration resulted in a significant reduction in Jno compared with administration of the saline solution control in healthy subjects, smokers, and COPD patients. Calv in smokers and in COPD patients was not completely inhibited 1 h after aminoguanidine inhalation, in marked contrast to previous results in asthma. Moreover, ONOO(-) and NO(2)(-)/NO(3)(-) levels were also increased in EBC and in sputum of smokers and COPD and were not completely inhibited following aminoguanidine inhalation. 8-Isoprostane levels were also increased in smokers and in COPD patients but were not reduced after aminoguanidine inhalation. CONCLUSIONS: These results suggest that the constitutive NOS isoform as well as iNOS might be involved in NO release and contribute to the high Calv and ONOO(-) production in patients with COPD. TRIAL REGISTRATION: Clinicaltrials.gov Identifier: NCT00180635.

Airway responsiveness and inflammation in adolescent elite swimmers.

BACKGROUND: Whereas increased airway hyperresponsiveness (AHR) and airway inflammation are well documented in adult elite athletes, it remains uncertain whether the same airway changes are present in adolescents involved in elite sport. OBJECTIVE: To investigate airway responsiveness and airway inflammation in adolescent elite swimmers. METHODS: We performed a cross-sectional study on adolescent elite swimmers (n = 33) and 2 control groups: unselected adolescents (n = 35) and adolescents with asthma (n = 32). The following tests were performed: questionnaire, exhaled nitric oxide (FeNO), spirometry, induced sputum, methacholine challenge, eucapnic voluntary hyperpnea (EVH) test, and exhaled breath condensate pH. RESULTS: There were no differences in FeNO, exhaled breath condensate pH, cellular composition in sputum, or prevalence of AHR to either EVH or methacholine among the 3 groups. When looking at airway responsiveness as a continuous variable, the swimmers were more responsive to EVH than unselected subjects, but less responsive to methacholine compared with subjects with asthma. We found no differences in the prevalence of respiratory symptoms between the swimmers and the unselected adolescents. There was no difference in FeNO, cellular composition of sputum, airway reactivity, or prevalence of having AHR to methacholine and/or EVH between swimmers with and without respiratory symptoms. CONCLUSION: Adolescent elite swimmers do not have significant signs of airway damage after only a few years of intense training and competition. This leads us to believe that elite swimmers do not have particularly susceptible airways when they take up competitive swimming when young, but that they develop respiratory symptoms, airway inflammation, and AHR during their swimming careers.

Lipopolysaccharide challenge of humans as a model for chronic obstructive lung disease exacerbations.

Endotoxin, or lipopolysaccharide (LPS), is a constituent of the outer cell membrane of Gram-negative bacteria. LPS is a highly potent proinflammatory substance, that, when inhaled, dose-dependently causes fever, chills, and bronchoconstriction. These symptoms are accompanied by a proinflammatory response in sputum and bronchoalveolar lavage fluid with elevation of neutrophils, macrophages and certain cytokines/chemokines. This response can be partially modified with certain drugs. Similar inflammatory changes are observed both in the stable state of chronic obstructive lung disease (COPD) and during exacerbations of this disease. Cigarette smoke, which contains bioactive LPS, is the most common cause of COPD and may also precipitate exacerbations. In addition, the presence of Gram-negative bacteria in the lower airways is a distinguishing feature both of stable COPD and of exacerbations. Based on this knowledge we argue here that inhaled LPS provocation of healthy volunteers can be used as a model or COPD as well as for exacerbations of this disease.

Effect of an inducible nitric oxide synthase inhibitor on differential flow-exhaled nitric oxide in asthmatic patients and healthy volunteers.

Nitric oxide (NO) is produced by a variety of cells within the respiratory tract, particularly airway epithelial cells, and its increased concentration in asthma is likely to derive from inducible NO synthase (iNOS) expressed in inflamed airways. To evaluate whether an increased bronchial flux of NO (ie, airway wall NO flux [Jno] in picoliters per second) produced in the large airways is due to an enzyme overexpression, we administered a relatively selective iNOS inhibitor, aminoguanidine, by nebulization in a double-blind, placebo-controlled manner in asthmatic and healthy subjects and also investigated whether the same concentration of inhibitor has any effect on NO produced in the peripheral lungs (ie, alveolar NO concentration [Calv] in parts per billion [ppb]) or on the diffusing capacity of NO (Dno) [in picoliters per second(-1) per ppb(-1)) in the airways. Aminoguanidine administration resulted in a significant reduction in Jno compared with administration of the saline solution control in eight healthy subjects and in eight patients with asthma but caused no significant changes in Calv or in Dno in either group. No rise in BP, fall in FEV(1), or adverse effects were observed in either group. These results indicate that iNOS from larger airways is the predominant source of elevated large airway-derived NO in patients with asthma, and that exhaled NO from peripheral lungs is not affected by a nebulized iNOS inhibitor and, therefore, is more likely to be derived form constitutive forms of NO synthase.

Loss of control of asthma following inhaled corticosteroid withdrawal is associated with increased sputum interleukin-8 and neutrophils.

BACKGROUND: The role of neutrophils in exacerbations of asthma is poorly understood. We examined the effect of withdrawal of inhaled corticosteroids on sputum inflammatory indexes in a double-blind study in patients with moderate, stable asthma. METHODS: Following a 2-week run in period, 24 subjects were randomized to receive either budesonide (400 microg bid) or placebo, and the study was continued for another 10 weeks. RESULTS: Loss of asthma control developed in 8 of 12 patients over the 10-week period of steroid withdrawal, whereas only 1 of 10 patients with budesonide treatment had exacerbations. Those with an exacerbation had increased sputum interleukin (IL)-8 (p < 0.0001) and increased sputum neutrophil numbers (p < 0.0001) compared to those without an exacerbation. The significant elevation in sputum IL-8 and neutrophil counts initially occurred 2 weeks prior to an exacerbation. Sputum neutrophilia correlated positively with changes in IL-8 levels (r(2) = 0.76, p = 0.01). CONCLUSIONS: Rapid withdrawal of inhaled corticosteroids results in an exacerbation of asthma that is preceded by an increase in sputum neutrophils and IL-8 concentrations, in contrast to an increase in eosinophils reported in previous studies in which inhaled steroids are slowly tapered.

Differential flow analysis of exhaled nitric oxide in patients with asthma of differing severity.

BACKGROUND: The majority of asthmatic patients achieve control of their illness; others do not. It is therefore crucial to validate/develop strategies that help the clinician monitor the disease, improving the response to treatment. METHODS: We have quantified the inflammation in central and peripheral airways by measuring exhaled nitric oxide (NO) at multiple exhalation flows in 56 asthmatics at different levels of severity (mild, n = 10; moderate stable, n = 17; moderate during exacerbation, n = 11; severe, n = 18, 7 of whom were receiving oral corticosteroids) and 18 healthy control subjects. The reproducibility of the measurement was also assessed. RESULTS: Bronchial NO (Jno) in patients with mild asthma (2,363 +/- 330 pL/s) [mean +/- SD] was higher than in patients with moderate stable asthma (1,300 +/- 59 pL/s, p < 0.0005), in patients with severe asthma receiving inhaled corticosteroids (ICS) [1,015 +/- 67 pL/s, p < 0.0005], and healthy control subjects (721 +/- 22 pL/s, p < 0.0001). There were no differences between Jno in patients with mild asthma compared to patients with severe asthma receiving ICS and oral corticosteroids (2,225 +/- 246 pL/s). Patients with exacerbations showed a higher Jno (3,475 +/- 368.9 pL/s, p < 0.05) compared to the other groups. Alveolar NO was higher in patients with severe asthma receiving oral corticosteroids (3.0 +/- 0.1 parts per billion [ppb], p < 0.0001) than in the other groups but was not significantly higher than in patients with moderate asthma during exacerbation (2.8 +/- 0.3 ppb). No differences were seen in NO diffusion levels between the different asthma groups. All the measurements were highly reproducible and free of day-to-day and diurnal variations. CONCLUSIONS: Differential flow analysis of exhaled NO provides additional information about the site of inflammation in asthma and may be useful in assessing the response of peripheral inflammation to therapy.

Normal bronchial blood flow in COPD is unaffected by inhaled corticosteroids and correlates with exhaled nitric oxide.

BACKGROUND: In COPD patients, there is reduced vascularity and inflammation of the bronchi, which may have opposite effects on bronchial blood flow (QAW). We studied the relationship of QAW with the fraction of exhaled nitric oxide (FENO), which is a potent vasodilator. We also investigated the vascular response to budesonide and a beta(2)-agonist. METHODS: We measured QAW in 17 patients with COPD (mean [+/- SEM] age, 67 +/- 3 years; 10 male patients; mean FEV(1), 57 +/- 3% predicted; mean FEV(1)/FVC ratio, 54 +/- 4%), all of whom were ex-smokers, and in 16 age-matched nonsmoking volunteers (mean age, 64 +/- 4 years) and compared this to FENO. QAW was measured using the acetylene dilution method. RESULTS: Mean QAW was similar in patients with COPD (34.29 +/- 1.09 microL/mL/min) compared to healthy subjects (35.50 +/- 1.74 microL/mL/min; p > 0.05) and was not affected by long-term treatment (35.89 +/- 1.63 microL/mL/min) or short-term treatment (32.50 +/- 1.24 microL/mL/min; p < 0.05) with inhaled budesonide. QAW positively correlated with the diffusion of carbon monoxide (ie, carbon monoxide transfer coefficient: r = 0.74; p < 0.05). FENO levels were mildly elevated in steroid-treated patients (10.89 +/- 0.87 parts per billion [ppb]) and untreated patients (9.40 +/- 0.86 ppb) compared to the control group (8.22 +/- 0.57 ppb; p < 0.05) and were correlated with QAW (r = 0.6; p < 0.05). Ten minutes after the inhalation of 200 microg of albuterol, QAW was more elevated in healthy control subjects (59.33 +/- 2.40 microL/mL/min) compared to COPD patients (38.00 +/- 0.58 microL/mL/min; p < 0.05), indicating that COPD patients may have a reduced bronchial vascular reactivity. CONCLUSIONS: QAW is normal in COPD patients and is not affected by therapy with inhaled corticosteroids or beta(2)-agonists. In addition, QAW correlates with levels of FENO, which may have a regulatory role.

Exhaled biomarkers.

Assessing airway and lung inflammation is important for investigating the underlying mechanisms of asthma and COPD. Yet these cannot be measured directly in clinical research and practice because of the difficulties in monitoring inflammation. Noninvasive monitoring may assist in early recognition of asthma and COPD, assessment of its severity, and response to treatment, especially during disease exacerbations. There is increasing evidence that breath analysis may have an important place in clinical management of asthma and COPD. The article reviews the role of current noninvasive measurements of exhaled gases, such as nitric oxide (NO), inflammatory markers in exhaled breath condensate (EBC), and exhaled breath temperature, as well as novel methods in monitoring and management of asthma and COPD.