Analysis of exhaled leukotrienes in nonasthmatic adult patients with seasonal allergic rhinitis

Variability of breath condensate pH may contribute to the better understanding of non-allergic seasonal respiratory diseases

The seasonal variability of certain non-allergic respiratory diseases is not clearly understood. Analysis of the breath condensate, the liquid that can be collected by breathing into a cold tube, has been proposed to bring closer to the understanding of airway pathologies. It has been assumed, that (1) airway lining fluid was a stable body liquid and (2) the breath condensate samples were representative of the airway lining fluid. Research was focussed on the identification of biomarkers indicative of respiratory pathologies. Despite 30 years of extended investigations breath condensate analysis has not gained any clinical implementation so far. The pH of the condensate is the characteristic that can be determined with the highest reproducibility. The present paper shows, that contrary to the initial assumptions, breath condensate is not a representative of the airway lining fluid, and the airway lining fluid is not a stable body liquid. Condensate pH shows baseline variability and it is influenced by drinking and by the ambient temperature. The changes in condensate pH are linked to changes in airway lining fluid pH. The variability of airway lining fluid pH may explain seasonal incidence of certain non-allergic respiratory diseases such as the catching of a common cold and the increased incidence of COPD exacerbations and exercise-induced bronchoconstriction in cold periods.

The association between asthma and rhinitis is stable over time despite diverging trends in prevalence

BACKGROUND

Despite the well-known association between asthma and rhinitis, in Swedish adults the prevalence of rhinitis rose from 22% to 31% between 1990 and 2008 while asthma prevalence was unchanged. We tested whether the association of rhinitis with asthma was stable over time using the same population-based databases.

METHODS

Two surveys of adults (20-44 years) living in three regions of Sweden, carried out in 1990 (n = 8982) and 2008 (n = 9156) were compared. Identical questions regarding respiratory symptoms, asthma and rhinitis were used. Asthmatic wheeze: Wheeze with breathlessness apart from colds. Current asthma: Asthma attacks and/or asthma medication use.

RESULTS

Subjects with rhinitis had level time trends in asthmatic wheeze, current asthma and most nocturnal respiratory symptoms between 1990 and 2008, adjusted for age, sex, area and smoking. Any wheeze however decreased slightly. In never-smokers asthma symptoms were similarly associated with rhinitis in 1990 and 2008: any wheeze OR 4.0 vs. 4.4 (p = 0.339); asthmatic wheeze OR 6.0 vs. 5.9 (p = 0.937); and current asthma OR 9.6 vs. 7.7 (p = 0.213). In the whole population there were decreases in the asthma symptoms most closely associated to smoking, which decreased by half 1990-2008. Conversely current asthma, which was strongly associated with rhinitis and not with smoking, increased (p < 0.001).

CONCLUSIONS

The association of rhinitis with asthma was stable between 1990 and 2008. The pattern in the time trends of asthma outcomes strongly suggests that decreased smoking counterbalanced the driving effect of increased rhinitis on asthma prevalence. The findings illustrate the public health benefits of decreased smoking.

Lung function and biomarkers of airway inflammation during and after hospitalization for acute exacerbations of childhood asthma associated with viral respiratory symptoms

BACKGROUND

There are limited data assessing relationships between biomarkers of inflammation and lung function after hospitalization for asthma exacerbations in children.

OBJECTIVE

To assess the associations in asthmatic children among changes in lung function, fraction of exhaled nitric oxide (FENO), and cysteinyl leukotrienes (CysLTs) in exhaled breath condensate (EBC) after hospitalization for acute asthma.

METHODS

Spirometry and FENO were measured and EBC collected for CysLT measurement from 40 children during and 1, 2, and 4 weeks after hospitalization for an asthma exacerbation and during a single-study visit for 40 healthy children.

RESULTS

Enrollment FENO and EBC CysLT concentrations were higher in the children with asthma than in healthy individuals (mean FENO, 31.6 vs 7 ppb; P < .0001; mean EBC CysLT, 7.9 vs 4.9 ppb; P = .03). Among children with asthma, improvement in lung function reached a plateau within 2 weeks after hospital discharge. The EBC CysLT concentrations were not associated with changes in lung function, use of albuterol, or use of inhaled corticosteroids (ICSs). Among asthmatic children enrollment FENO was not associated with changes in lung function during follow-up. However, among children who had an elevated enrollment FENO (≥25 ppb), patients who did not use ICSs after hospital discharge had lower end-of-study lung function than those who used ICSs. At 2 and 4 weeks after hospital discharge, FENO was higher among patients who reported albuterol use more than twice weekly and among patients who reported no ICS use.

CONCLUSION

FENO measured at hospital discharge among children hospitalized with acute asthma may be useful in identifying patients who will respond to ICS therapy.

Leukotriene B4, administered via intracerebroventricular injection, attenuates the antigen-induced asthmatic response in sensitized guinea pigs

Background

Despite intensive studies focused on the pathophysiology of asthmatic inflammation, little is known about how cross-talk between neuroendocrine and immune systems regulates the inflammatory response during an asthmatic attack. We recently showed corresponding changes of cytokines and leukotriene B₄ (LTB₄) in brain and lung tissues of antigen-challenged asthmatic rats. Here, we investigated how LTB₄ interacts with the neuroendocrine-immune system in regulating antigen-induced asthmatic responses in sensitized guinea pigs.

Methods

Ovalbumin-sensitized guinea pigs were challenged by inhalation of antigen. Vehicle, LTB₄ or U75302 (a selective LTB₄ BLT1 receptor inhibitor) was given via intracerebroventricular injection (i.c.v.) 30 min before challenge. Airway contraction response was evaluated using Penh values before and after antigen challenge. The inflammatory response in lung tissue was evaluated 24 h after challenge. The LTB₄ content of lung and brain homogenate preparations was detected by reversed phase high-performance liquid chromatography (RP-HPLC). Plasma levels of adrenocorticotropic hormone (ACTH) and corticosterone (CORT) were measured using ELISA kits.

Results

Antigen challenge impaired pulmonary function and increased inflammatory cell infiltration in lung tissue. These responses could be significantly suppressed by LTB₄, 30 ng i.c.v., in ovalbumin-sensitized guinea pigs. LTB₄ content of lung and brain homogenates from antigen-challenged guinea pigs was significantly increased. In addition, administration of LTB₄ via i.c.v. markedly increased CORT and ACTH level in plasma before antigen challenge, and there were further increases in CORT and ACTH levels in plasma after antigen challenge. U75302, 100 ng i.c.v., completely blocked the effects of LTB₄. In addition, U75302, 100 ng via i.c.v. injection, markedly decreased LTB₄ content in lung homogenates, but not in brain homogenates.

Conclusions

Increased LTB₄ levels in brain during asthmatic attacks down-regulates airway contraction response and inflammation through the BLT1 receptor. Stimulation of the hypothalamic-pituitary-adrenal axis by LTB₄ may result in an increase in systemic glucocorticoids which, in turn, would feed back to suppress the asthmatic response.

Breath markers of oxidative stress and airway inflammation in Seasonal Allergic Rhinitis

Oxidative stress (OS) is well documented in asthma, but so far, little data has been reported in nonasthmatic patients with Seasonal Allergic Rhinitis (SAR). The aim of this study is to investigate the degree of OS and airway inflammation in patients with SAR, with and without concomitant asthma (SAR+A), using breath markers in exhaled air and in Exhaled Breath Condensate (EBC). In addition, the effects of natural allergen exposure and intranasal steroid treatment on these markers were evaluated. Exhaled NO (eNO) and CO, combined with measurements of 8-Isoprostane (Iso-8), Leukotriene B4 (LTB4) and nitrate/nitrite in EBC, were performed in 23 patients, 11 with SAR and 12 with SAR+A, and 16 healthy subjects. Iso-8 and LTB4 were significantly increased in both groups of patients (median values 43.6 pg/ ml and 138.4 pg/ml in SAR group; 38.9 pg/ml, and 164.6 pg/ml in SAR+A group respectively; p>0.05) compared to healthy subjects (18.6 pg/ml and 7.8 pg/ml; p<0.05). Nitrate/nitrite and eNO levels were elevated in both groups compared to controls, but were significantly higher in the SAR+A compared to SAR group (nitrate/nitrite 9 microM and 3.9 microM; p=0.025; and eNO 18.5 ppb and 12.5 ppb, respectively; p>0.05). Nasal steroids caused significant reduction in LTB4 and 8-isoprostane levels in both groups of patients (p<0.05), while nitrate levels and eNO concentration were little affected by nasal treatment. OS markers were decreased at normal levels out of pollen season. Natural allergen exposure induces OS and airway inflammation, as assessed by measurements of markers in EBC and exhaled air, in patients with SAR who have no clinical signs of lower airway involvement. Besides, intranasal steroid treatment may have a regulatory role in the OS.

Inflammatory and oxidative stress biomarkers in allergic rhinitis: the effect of smoking

BACKGROUND

Accumulating evidence confirms the presence of pan-airway inflammation in allergic rhinitis patients. Smoking is known to affect the asthmatic airway inflammation. However, no study has evaluated the impact of smoking on airway inflammation of allergic rhinitis patients.

OBJECTIVE

The aim of the present study was to evaluate the impact of smoking on inflammatory and oxidative stress biomarkers in patients with seasonal allergic rhinitis, using non-invasive methods for sample collection.

METHODS

Forty patients with seasonal allergic rhinitis (20 smokers and 20 non-smokers) and 30 healthy subjects (15 smokers and 15 non-smokers) were recruited for the study during pollen season. All subjects were submitted to measurement of the fraction of exhaled NO (FeNO), exhaled breath condensate (EBC) collection, nasal lavage collection, pre- and post- bronchodilation spirometry and metacholine bronchial challenge testing. pH, leukotriene B(4) (LTB(4)) and 8-isoprostane were determined in EBC and nasal lavage samples.

RESULTS

Patients with allergic rhinitis presented higher LTB(4) and 8-isoprostane levels in nasal lavage (P<0.0001 for both comparisons), with no significant differences between smokers and non-smokers. Patients with allergic rhinitis also presented higher LTB(4) levels and lower pH in EBC (P<0.001 and P=0.004, respectively), with prominent differences between smokers and non-smokers (P<0.0001 and P=0.003, for LTB(4) and pH, respectively). A significant correlation between nasal lavage and EBC LTB(4) values was observed (r(s)=0.313, P=0.048).

CONCLUSIONS

Patients with allergic rhinitis present increased LTB(4) and 8-isoprostane in their nasal cavity, however, with no significant differences between smokers and non-smokers. In contrast, smokers with allergic rhinitis present higher LTB(4) levels and lower pH in EBC, suggesting that these patients may be more susceptible to the deleterious effects of smoking, compared with non-smokers.

Exhaled leukotrienes and bronchial responsiveness to methacholine in patients with seasonal allergic rhinitis

BACKGROUND

Allergic rhinitis and bronchial asthma can coexist and affect each other.

OBJECTIVE

To investigate the relationship between the postseasonal increase in the concentration of leukotriene (LT) B4 and LTE4 in exhaled breath condensate (EBC) and bronchial responsiveness to methacholine (BRM) in patients with seasonal allergic rhinitis (SAR).

METHODS

In 28 patients with SAR and 50 healthy study patients, the leukotrienes were measured in EBC during and after the pollen season by gas chromatography/mass spectrometry. The BRM was determined after the pollen season.

RESULTS

In 7 patients with SAR, significantly increased concentrations of both the leukotrienes were found in EBC during and 5 months after the pollen season. The following seasonal and postseasonal median values were measured in patients with SAR in comparison with control patients: LTB4: 131 and 90 pg/mL vs 80 and 79 pg/mL, P < .001 and P = .03, respectively; LTE4: 122 and 86 pg/mL vs 76 and 74 pg/mL, P < .001 and P = .02, respectively. Five months after the pollen season, the concentrations of LTB4 and LTE4 decreased with respect to their seasonal values (90 and 86 pg/mL, respectively, P < .001, for both leukotrienes). In 7 patients with SAR and leukotriene levels exceeding the reference limits, significantly increased BRM was also found (LTB4: P = .02; LTE4: P = .002).

CONCLUSIONS

The seasonal and postseasonal increases in LTB4 and LTE4 concentrations in EBC of the patients with SAR correlated significantly with the later increase in BMR. This relationship could provide a useful predictive parameter for early inflammatory processes in the lower airways of patients with allergic rhinitis.

Phosphorylation of serine 271 on 5-lipoxygenase and its role in nuclear export

The enzyme 5-lipoxygenase (5-LO) initiates the biosynthesis of leukotrienes, inflammatory mediators involved in immune diseases and defense. The subcellular localization of 5-LO is regulated, with nuclear import commonly leading to increased leukotriene production. We report here that 5-LO is constitutively phosphorylated on Ser-271 in transfected NIH 3T3 cells. This residue is nested in a classical nuclear export sequence, and phosphorylated Ser-271 5-LO was exclusively found in the nucleus by immunofluorescence and by fractionation techniques. Mutation of Ser-271 to Ala allowed nuclear export of 5-LO that was blocked by the specific nuclear export inhibitor leptomycin b, suggesting that phosphorylation of Ser-271 serves to interfere with exportin-1-mediated nuclear export. Consistent with previous reports that purified 5-LO can be phosphorylated on Ser-271 in vitro by MAPK-activated protein kinase 2, the nuclear export of 5-LO was increased by either treatment with the p38 inhibitor SB 203,580 or co-expression of a kinase-deficient p38 MAPK. Nuclear export of 5-LO can also be induced by KN-93, an inhibitor of Ca2+/calmodulin-dependent kinase II, and the effects of SB 203,580 plus KN-93 are additive. Finally, HeLa cells, which lack nuclear 5-LO, also lack constitutive phosphorylation of Ser-271. Taken together, these results indicate that the phosphorylation of Ser-271 serves to inhibit the nuclear export of 5-LO. This action works in concert with nuclear import, which is regulated by phosphorylation on Ser-523, to determine the subcellular distribution of 5-LO, which in turn regulates leukotriene biosynthesis.

Biomarkers in exhaled breath condensate: a review of collection, processing and analysis

Exhaled breath condensate (EBC) is a potential rich source for countless biomarkers that can provide valuable information about respiratory as well as systemic diseases. EBC has been studied in a variety of diseases including allergic rhinitis, asthma, chronic obstructive lung disease, cystic fibrosis, lung cancer, and obstructive sleep apnea syndrome. Although numerous biomarkers have been discovered and studied in EBC, the methods of collection and biomarker detection have not been fully standardized. While leaving standardization methods up to individual labs for the present time is optimal for the continued discovery of new biomarkers in EBC, this decreases the reproducibility and generalizability of the findings. In this review we will discuss specific biomarkers studied in specific diseases as well as some of the related technical issues including collection, processing and analysis.

Selected ion flow tube mass spectrometry of exhaled breath condensate headspace

Collection of exhaled breath condensate (EBC) is a relatively simple noninvasive method of breath analysis; however, no data have been reported that would relate concentration of volatile compounds in EBC to their gaseous concentrations in exhaled air. The aim of the study was to investigate which volatile compounds are present in EBC and how their concentrations relate to results of direct breath analysis. Thus, samples of EBC were collected in a standard way from several subjects and absolute levels of several common volatile breath metabolites (ammonia, acetone, ethanol, methanol, propanol, isoprene, hydrogen cyanide, formaldehyde and acetaldehyde) were then determined in their headspace using selected ion flow tube mass spectrometry (SIFT-MS). Results are compared with those from on-line breath analyses carried out immediately before collecting the EBC samples. It has been demonstrated that SIFT-MS can be used to quantify the concentrations of volatiles in EBC samples and that, for methanol, ammonia, ethanol and acetone, the EBC concentrations correlate with the direct breath levels. However, the EBC concentrations of isoprene, formaldehyde, acetaldehyde, hydrogen cyanide and propanol do not correlate with direct breath measurements.

Exhaled bronchial cysteinyl leukotrienes in allergic patients

PURPOSE OF REVIEW

To review the current knowledge of noninvasive monitoring of allergic airway inflammation by analysis of leukotrienes in the exhaled breath condensate.

RECENT FINDINGS

Treatment of respiratory allergies involves chronic treatment based on clinical symptoms and pulmonary function tests. Evaluation of local inflammation would be desirable but is currently not feasible because of the difficulty in sampling the airways. Recently, exhaled breath condensate collection and analysis has polarized much interest in the respiratory field. Although some methodological issues are still under scrutiny, airways inflammatory markers can be assayed with this technique. In particular, exhaled breath condensate leukotrienes have been thoroughly investigated in the setting of bronchial asthma and allergic rhinitis in adults and children. Exhaled leukotrienes are increased in patients with asthma and rhinitis during the pollen season, correlate with exacerbations and asthma severity, and are reduced by specific anti-inflammatory treatment and allergen avoidance.

SUMMARY

Some issues still prevent the use of exhaled breath condensate in clinical practice but in the research setting it has been proved to be useful for noninvasive monitoring of allergic inflammation in the lung. In particular, exhaled leukotrienes may represent valuable biomarkers for diagnostic and therapeutic purposes in allergic patients.

The effect of allergic rhinitis on adenosine concentration in exhaled breath condensate

BACKGROUND

Patients with allergic rhinitis (AR) frequently develop asthma. This initiating inflammation in the lower airways may result in increased levels of inflammatory mediators such as adenosine in the exhaled breath.

OBJECTIVE

We compared adenosine levels in exhaled breath condensate (EBC) and both exhaled and nasal nitric oxide (NO) levels of AR patients and healthy control subjects. We also tested whether inhalation through inflamed nasal cavity during EBC sampling influences adenosine concentrations in exhaled air.

METHODS

Exhaled and nasal NO levels were measured and EBC samples (at oral inhalation) were collected from 27 patients and 15 healthy controls. EBC collection was repeated after 15 min with subjects inhaling through their nose. Adenosine was measured by HPLC and NO was determined by chemiluminescence.

RESULTS

The concentration of EBC adenosine was higher in patients with AR than in healthy controls (12.4+/-1.3 nM vs. 6.5+/-0.7 nM, P=0.0019) and this was accompanied by an increase in the concentration of exhaled NO (10.2+/-1.3 ppb vs. 5.3+/-0.5 ppb; P=0.0099, respectively). No difference in nasal NO was detected. EBC adenosine concentration showed a significant positive correlation with the level of exhaled NO. In contrast to healthy control subjects, patients with rhinitis had higher levels of exhaled adenosine when inhaling via the nose instead of the mouth (17.7+/-2.8 nM, P=0.007).

CONCLUSION

When compared with healthy subjects, patients with AR exhibit an increased concentration of exhaled adenosine and a related increase in exhaled NO concentration. EBC adenosine is further increased when rhinitis patients inhale through their nose than via their mouth. Our data suggest that non-asthmatic patients with rhinitis may have subclinical inflammation in their lower airways.

Intranasal steroid reduces exhaled bronchial cysteinyl leukotrienes in allergic patients

BACKGROUND

Allergic rhinitis (AR) precedes and is often associated with bronchial asthma. Indeed, local and systemic inflammations in both conditions are very similar. Cysteinyl-leukotrienes (cys-LTs) are generated during early- and late-phase allergic reactions and induce smooth-muscle contraction, microvascular leakage, and mucous hypersecretion. Cys-LTs are detected in exhaled breath condensate (EBC) of asthmatics and regardless of bronchial symptoms, they are also found in EBC of rhinitic patients.

OBJECTIVE

To evaluate cys-LTs in EBC of allergic patients and to assess the activity of nasal fluticasone propionate (FP) on EBC cys-LTs levels.

METHODS

Cys-LTs coefficient of variation (CV) was evaluated from different EBC in 5 healthy volunteers. Cys-LTs levels from EBCs in 13 healthy controls and 56 allergic rhinitic (n=31) and rhinitic/asthmatic (n=25) patients were also evaluated at baseline. Subsequently patients were randomized to receive either FP 100 microg/day per nostril or placebo for 2 weeks and then re-evaluated for EBC cys-LTs.

RESULTS

The CV was 14.12%. EBC cys-LTs in allergic patients were significantly higher than in healthy subjects (70.9 vs. 20.6 pg/mL (median), P<0.05), while it did not differ between asthmatic/rhinitic and purely rhinitic patients. Treatment significantly reduced cys-LTs (from 93.6 to 19.9 pg/mL, P<0.001). This effect was evident both in asthmatic/rhinitic and in rhinitic patients.

CONCLUSION

Treatment of AR with FP significantly reduces the levels of cys-LTs, major noninvasive markers of lower airway inflammation, suggesting that upper and lower airway inflammation is present and should be thus treated as a whole in subjects with AR with and without asthma.

Expression of 5-lipoxygenase in specialized epithelial cells of nasopharyngeal-associated lymphoid tissue

Leukotrienes are lipid mediators that are produced primarily by certain types of leukocytes. The synthesis of the leukotriene LTB(4) is initiated by the enzyme 5-lipoxygenase and completed by LTA(4) hydrolase. Epithelial cells constitutively express LTA(4) hydrolase but normally lack 5-lipoxygenase. In this study, we report that the stratified squamous epithelial cells from inflamed or hyperplastic tissues of palatine and pharyngeal tonsils (nasopharyngeal-associated lymphoid tissue) express 5-lipoxygenase protein. The localization of 5-lipoxygenase was indicated by immunohistochemical staining and presence confirmed by immunoblot. Positive staining for 5-lipoxygenase in infiltrating leukocytes in inflamed tissues served as internal positive controls for immunohistochemical staining. Staining for 5-lipoxygenase in appendix tissue was negative for epithelial cells while positive for polymorphonuclear leukocytes, indicating that 5-lipoxygenase expression is not a general feature of epithelial cells in mucosa-associated lymphoid tissue. In tonsils, 5-lipoxygenase staining was pronounced in broad regions but reduced or absent in others, suggesting regional regulation of expression. Epithelial cells of tonsils were also positive for 5-lipoxygenase activating protein and leukotriene A(4) hydrolase, indicating a capacity to produce LTB(4). Taken together, these results suggest that the specialized epithelial cells of the mucosa-associated lymphoid tissue of human tonsils can synthesize LTB(4). This lipid mediator may serve to modulate the function of cells within the lymphoid tissue as well as promote an inflammatory response.

Methodological improvements for measuring eicosanoids and cytokines in exhaled breath condensate

BACKGROUND

Exhaled breath condensate (EBC) is simple to collect and as such a non-invasive method that has attracted substantial interest in the last few years. However, several methodological concerns have been raised and it has been difficult to reproduce results between different centres. Because of low concentrations of inflammatory markers, potential loss in the sampling system may have great influence. The aim of the present study was to se if evaporation and plastic coating could facilitate detection.

METHODOLOGY

Through methodological improvements, we have now made it possible to measure EBC concentrations of eicosanoids and cytokines in our system. Due to absorbance of both fatty acid derivates and proteins to several plastics, the first step is coating of all surfaces with bovine serum albumin and Tween 20. Since several assays are sensitive to these factors, the methodology has to be standardised to avoid false results. Secondly, larger amounts of EBC have to be vacuum-dried, and thereafter resolved in the respective assay buffers. The EBCs have to be concentrated 5-10 times, depending on samples and assay sensitivity.

RESULTS

Due to these improvements we can measure, for example, cysteinyl-leukotrienes, leukotriene B4, prostaglandin E and 8-isoprostane. High sensitivity assays have also made it possible to measure cytokines, for example, interleukin (IL)-1beta, IL-8 and IL-13.

SUMMARY

We are aware of different results from other labs. However, it seems essential to coat and to concentrate the samples in order to achieve reliable and measurable results.