Inflammatory mediators in exhaled breath, induced sputum and saliva

Challenges in Quantifying 8-OHdG and 8-Isoprostane in Exhaled Breath Condensate

Exhaled breath condensate (EBC) has attracted substantial interest in the last few years, enabling the assessment of airway inflammation with a non-invasive method. Concentrations of 8-Hydroxydesoxyguanosine (8-OHdG) and 8-isoprostane in EBC have been suggested as candidate biomarkers for lung diseases associated with inflammation and oxidative stress. EBC is a diluted biological matrix and consequently, requires highly sensitive chemical analytic methods (picomolar range) for biomarker quantification. We developed a new liquid chromatography coupled to tandem mass spectrometry method to quantify 8-OHdG and 8-isoprostane in EBC simultaneously. We applied this novel biomarker method in EBC obtained from 10 healthy subjects, 7 asthmatic subjects, and 9 subjects with chronic obstructive pulmonary disease. Both biomarkers were below the limit of detection (LOD) despite the good sensitivity of the chemical analytical method (LOD = 0.5 pg/mL for 8-OHdG; 1 pg/mL for 8-isoprostane). This lack of detection might result from factors affecting EBC collections. These findings are in line with methodological concerns already raised regarding the reliability of EBC collection for quantification of 8-OHdG and 8-isoprostane. Precaution is therefore needed when comparing literature results without considering methodological issues relative to EBC collection and analysis. Loss of analyte during EBC collection procedures still needs to be resolved before using these oxidative stress biomarkers in EBC.

Oxylipin profile in saliva from patients with cystic fibrosis reveals a balance between pro-resolving and pro-inflammatory molecules

Oxylipins are signaling molecules originated by fatty acids that modulate vascular and bronchial tone, bronchial secretion, cytokine production and immune cell activity. The unbalanced production of pro-inflammatory and pro-resolving (i.e., anti-inflammatory) oxylipins has a relevant role in the pathogenesis of pulmonary inflammation like in cystic fibrosis (CF). We analyzed by LC-MRM/MS 65 oxylipins and 4 fatty acids in resting saliva from 69 patients with CF and 50 healthy subjects (controls). The salivary levels of 48/65 oxylipins were significantly different between CF patients and controls. Among these, EpETE, DHET, 6ketoPGE1 and HDHA were significantly higher in saliva from CF patients than in controls. All these molecules display anti-inflammatory effects, i.e., releasing of bronchial and vascular tone, modulation of cytokine release. While 20-hydroxyPGF2A, PGB2, EpDPE, 9 K-12-ELA, bicyclo-PGE2, oleic acid, LTC4, linoleic acid, 15oxoEDE, 20 hydroxyPGE2 and DHK-PGD2/PGE2 (mostly associated to pro-inflammatory effects) resulted significantly lower in CF patients than in controls. Our data suggest that the salivary oxylipins profile in CF patients is addressed toward a global anti-inflammatory effect. Although these findings need be confirmed on larger populations in prospective studies, they will contribute to better understand the pathogenesis of CF chronic inflammation and to drive targeted therapies based on the modulation of oxylipins synthesis and degradation.

Evaluating Cytokines in Immunotoxicity Testing

One of the most powerful tools in immunotoxicology is the assessment of cytokines, the proteins/peptides responsible for regulating a variety of processes including immunity, inflammation, apoptosis, and hematopoiesis. Cytokine production measurements offer outstanding information and may eventually substitute for other more laborious procedures in the assessment of immunotoxicity. The particular profile of cytokine production provides indeed important information regarding the nature of many immunotoxic responses.Recent expansion in the knowledge of cytokine biology and the realization that cytokines play a role in human diseases have created a need for the precise assessment and accurate interpretation of their presence and activity in body fluids, tissues, and cells. Proper evaluation of cytokines requires attention to several technical details. Multi-cytokine analysis still needs to be standardized in terms of optimum source for analysis, protocols, and quality control issues, such as the use of reference standards and the expression of results.Important practical details and considerations will be discussed in this chapter, including the source of the sample to be tested (circulating fluids or ex vivo/in vitro isolated cells); the potential effects of collection, processing, and storage of the results of the assays, as well as potential variables associated with the source material (matrix effects, relevance, inhibitory substances); and factors influencing the choice of assay used (bioassay, immunoassay, molecular biology technique, flow cytometry).

Biomarkers in adult asthma: a systematic review of 8-isoprostane in exhaled breath condensate

OBJECTIVES

We aimed to assess the evidence for the use of 8-isoprostane in exhaled breath condensate (EBC) as a biomarker in adult asthma.

DESIGN

A systematic review and meta-analysis of EBC 8-isoprostane.

METHODS

We searched a number of online databases (including PubMed, Embase and Scopus) in January 2016. We included studies of adult non-smokers with EBC collection and asthma diagnosis conducted according to recognised guidelines. We aimed to pool data using random effects meta-analysis and assess heterogeneity using I ².

RESULTS

We included twenty studies, the findings from which were inconsistent. Seven studies (n = 329) reported 8-isoprostane levels in asthma to be significantly higher than that of control groups, whilst six studies (n = 403) did not. Only four studies were appropriate for inclusion in a random effects meta-analysis of mean difference. This found a statistically significant between-groups difference of 22 pg ml^-1. Confidence in the result is limited by the small number of studies and by substantial statistical heterogeneity (I ² = 94).

CONCLUSION

The clinical value of EBC 8-isoprostane as a quantitative assessment of oxidative stress in asthma remains unclear due to variability in results and methodological heterogeneity. It is essential to develop a robust and standardised methodology if the use of EBC 8-isoprostane in asthma is to be properly evaluated.

Does aspirin-induced oxidative stress cause asthma exacerbation?

Aspirin-induced asthma (AIA) is a distinct clinical syndrome characterized by severe asthma exacerbations after ingestion of aspirin or other non-steroidal anti-inflammatory drugs. The exact pathomechanism of AIA remains unknown, though ongoing research has shed some light. Recently, more and more attention has been focused on the role of aspirin in the induction of oxidative stress, especially in cancer cell systems. However, it has not excluded the similar action of aspirin in other inflammatory disorders such as asthma. Moreover, increased levels of 8-isoprostanes, reliable biomarkers of oxidative stress in expired breath condensate in steroid-naïve patients with AIA compared to AIA patients treated with steroids and healthy volunteers, has been observed. This review is an attempt to cover aspirin-induced oxidative stress action in AIA and to suggest a possible related pathomechanism.

Sputum periostin in patients with different severe asthma phenotypes

BACKGROUND

Identifying inflammatory phenotypes is relevant in severe uncontrolled asthma. The aim of this study was to identify the different clinical, inflammatory, functional, and molecular phenotypes in patients with severe asthma and to investigate the potential role of sputum periostin as a biomarker of severe asthma phenotypes.

PATIENTS AND METHODS

Sputum induction was performed in 62 patients diagnosed with severe asthma. Skin prick testing, lung function tests, exhaled nitric oxide, hematimetry, and total serum IgE were performed. Periostin was measured in sputum supernatants.

RESULTS

Patients with asthma were phenotyped and 80% had late-onset asthma, 50% had fixed airflow obstruction, and 66% showed a Th2-high phenotype. With respect to inflammatory phenotypes, 71% were eosinophilic and 25% mixed granulocytic. Periostin levels were higher in patients with fixed as compared to variable airflow limitation (69.76 vs 43.84 pg/ml, P < 0.05) and in patients with eosinophilic as compared to mixed granulocytic phenotype (61.58 vs 37.31 pg/ml, P < 0.05). There was an inverse correlation between postbronchodilator FEV1 /FVC and periostin levels (-0.276, P < 0.05).

CONCLUSION

This study demonstrates the utility of periostin in phenotyping severe asthma. Periostin levels in sputum are associated with persistent airflow limitation in asthma patients with airway eosinophilia despite treatment with high-dose inhaled corticosteroids.

Increased of exhaled breath condensate neutrophil chemotaxis in acute exacerbation of COPD

Background

Neutrophils have been involved in the pathogenesis of chronic obstructive pulmonary disease (COPD). Underlying mechanisms of neutrophil accumulation in the airways of stable and exacerbated COPD patients are poorly understood. The aim of this study was to assess exhaled breath condensate (EBC) neutrophil chemotactic activity, the level of two chemoattractants for neutrophils (GRO-α and LTB4) during the course of an acute exacerbation of COPD (AECOPD).

Methods

50 ex smoking COPD patients (33 with acute exacerbation and 17 in stable disease) and 20 matched ex smoking healthy controls were compared. EBC was collected by using a commercially available condenser (EcoScreen®). EBC neutrophil chemotactic activity (NCA) was assessed by using Boyden microchambers. Chemotactic index (CI) was used to evaluate cell migration. LTB₄ and GROα levels were measured by a specific enzyme immunoassay in EBC.

Results

Stable COPD and outpatients with AECOPD, but not hospitalized with AECOPD, had raised EBC NCA compared to healthy subjects (p < 0.05 and p < 0.01 respectively). In outpatients with AECOPD EBC NCA significantly decreased 6 weeks after the exacerbation. Overall EBC NCA was weakly correlated with sputum neutrophil counts (r = 0.26, p < 0.05).

EBC LTB4 levels were increased in all groups of COPD compared to healthy subjects while GRO-α was only raised in patients with AECOPD. Furthermore, EBC LTB₄ and GRO-α significantly decreased after recovery of the acute exacerbation. Increasing concentrations (0.1 to 10 μg/mL) of anti- human GRO-α monoclonal antibody had no effect on EBC neutrophil chemotactic activity of 10 exacerbated COPD patients.

Conclusions

EBC NCA rose during acute exacerbation of COPD in ambulatory patients and decreased at recovery. While LTB4 seems to play a role both in stable and in exacerbated phase of the disease, the role of GRO-α as a chemotactic factor during AECOPD is not clearly established and needs further investigation.

Association of pro-inflammatory cytokines, cortisol and depression in patients with chronic obstructive pulmonary disease

Evidence suggests that pro-inflammatory cytokines and cortisol play a crucial role in the etiology of chronic obstructive pulmonary disease (COPD) and depression. Depression occurs commonly among COPD patients and an earlier diagnosis would be beneficial. This study investigated the associations between depression, sputum cytokines and salivary cortisol in COPD patients. The diurnal rhythms of sputum IL-1, IL-6, TNF-α and salivary cortisol were measured in COPD patients with depression compared to those only with depression, or COPD and healthy controls. The area under the diurnal variation curves (AUC) over the 24h time course and relative diurnal variation (VAR) were calculated while correlation and regression analysis were performed. Patients with co-morbid depression and COPD showed an increasing sputum IL-1, sputum TNF-α AUC and a decreasing salivary cortisol VAR (P<0.001). The combination of sputum TNF-α AUC, sputum IL-1 AUC, sputum IL-6 AUC and salivary cortisol VAR performed best as a potential biomarker in the diagnosis of depression in COPD patients, with a sensitivity of 94.74% and a specificity of 96.67%. Positive correlations were found between sputum IL-1 AUC and sputum TNF-α AUC versus depressive symptoms, respectively a negative correlation was found between salivary cortisol VAR and depression. They were independently associated with depression in logistic regression models. Depression in COPD is associated with higher 24-h overall levels of sputum IL-1, TNF-α and flattened diurnal salivary cortisol. These non-invasive sputum and salivary biomarkers may serve as a simple clinical tool for the early diagnosis of depression in COPD patients.

Pepsin levels and oxidative stress markers in exhaled breath condensate of patients with gastroesophageal reflux disease

AIM

To evaluate the pepsin and oxidative stress markers in exhaled breath condensate (EBC) in patients with gastroesophageal reflux disease (GERD).

PATIENTS AND METHOD

Patients with a presumptive diagnosis of GERD with recurrent respiratory and gastrointestinal problems aged between 2 and 14 years were included in the study. All patients underwent pH monitoring. Patients with a reflux index (RI) ≥4 were assessed as the reflux group, and those with an RO <4 were assessed as the non-reflux group. Pepsin levels and oxidative stress markers [NO metabolites (NOX) and total sulphydrile (TSH) levels] were measured in the EBC.

RESULTS

There were 24 patients in the reflux group [RI 17.6 (6.6-46.4)] [median, interquartile range] and 23 in the non-reflux group [RI 0.8 (0.5-1.9) (p<0.001). Pepsin levels in the EBC were below the level of detection. The median levels of NOx in the EBC of children with reflux [13.7 μmol/L (7.3-24.5)] were lower in than non-reflux group [21.0 μmol/L (14.0-25.2)] (p=0.034). There was a negative correlation between reflux index and NOX levels in EBC (rs: -0.331, p=0.023). In contrast, there was no difference in TSH levels between the reflux and non-reflux groups [37.4 μmol/L (30.2-44.6) vs 40.1 μmol/L (37.4-44.9), respectively, (p>0.05)].

CONCLUSION

Decreased levels of NOX in patients with GER disease suggest increased oxidative stress in airways of these patients.

The role of exhaled nitric oxide and exhaled breath condensates in evaluating airway inflammation in asthma

BACKGROUND

Airway inflammation is central to the development and progression of asthma. Monitoring airway inflammation can be invasive and technically difficult, making its use limited in clinical practice. Several advances have been made in non-invasive techniques to monitor and measure inflammation from the airways.

OBJECTIVE

To examine the suitability of exhaled nitric oxide and exhaled breath condensates as diagnostic tools in asthma.

METHOD

The current literature regarding the use of exhaled nitric oxide and exhaled breath condensate to assess and manage asthma was reviewed.

CONCLUSION

Exhaled nitric oxide is a clinically useful marker of eosinophilic airway inflammation in asthma. Although showing promise, significant validation and investigation are required before exhaled breath condensate could be utilized in clinical practice.

Airway inflammation and hypothalamic-pituitary-adrenal axis activity in asthmatic adults with depression

OBJECTIVE

To investigate the features of airway inflammation and hypothalamic-pituitary-adrenal axis (HPAA) activity in patients with asthma accompanied by depression.

METHODS

Adult asthmatics were recruited and enrolled into one of the two groups based on scores on the Hamilton Depression Rating Scale (HAMD): asthmatics with depression (HAMD score ≥8, n = 23), and asthmatics without depression (HAMD score <8, n = 41). In addition, 27 healthy individuals and 21 adults with depression only were enrolled as controls. Induced sputum and blood samples were collected for measurement of cytokines and other inflammatory factors. The diurnal rhythm profiles of salivary cortisol and other hormones were obtained for assessment of the HPAA activity.

RESULTS

For the group of asthmatics with depression, the mean HAMD score was 19.0, and for the group of asthmatics without depression, the HAMD score averaged 4.9(p < .001). Serum and sputum tumor necrosis factor alpha (TNF-α) were significantly higher in asthmatics with depression than those in the other groups (p < .05) while serum interferon-gamma (IFN-γ) was lower in asthmatics with depression than that in the other groups (p < .05). Twenty-four-hour urinary cortisol, salivary cortisol at 8 a.m. and 4 p.m. were lower in asthmatics with depression compared to other groups (p < .05).

CONCLUSIONS

As compared to healthy individuals and those with asthma or depression alone, individuals with comorbid depression and asthma showed the highest level of pro-inflammatory cytokines and the lowest level of anti-inflammatory cytokines and cortisol. These observations may serve as a valuable reference for diagnosis and clinic therapies of depression in asthmatics.

Induced sputum, exhaled NO, and breath condensate in occupational medicine

OBJECTIVE

Studies of fractional exhaled NO (FeNO) or induced sputum are now well standardized and the exponential increase in publications about exhaled breath condensate reflects growing interest in a noninvasive diagnosis of pulmonary diseases in occupational medicine.

METHODS

This review describes current techniques (FeNO, induced sputum, and exhaled breath condensate) for the study of inflammation and oxidative stress biomarkers.

RESULTS

These biomarkers are FeNO, cytokines, H2O2, 8-isoprostane, malondialdehyde, and nitrogen oxides. These techniques also include the study of markers of the toxic burden in the lungs (heavy metals and mineral compounds) that are important in occupational health exposure assessment.

CONCLUSIONS

In occupational medicine, the study of both volatile and nonvolatile respiratory biomarkers can be useful in medical surveillance of exposed workers, the early identification of respiratory diseases, or the monitoring of their development.

Profiling the proteome of exhaled breath condensate in healthy smokers and COPD patients by LC-MS/MS

Three pools of exhaled breath condensate (EBC) from non-smokers plus healthy smokers (NS + HS, n = 45); chronic obstructive pulmonary disease (COPD) without emphysema (COPD, n = 15) and subjects with pulmonary emphysema associated with α₁-antitrypsin deficiency (AATD, n = 23) were used for an exploratory proteomic study aimed at generating fingerprints of these groups that can be used in future pathophysiological and perhaps even clinical research. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was the platform applied for this hypothesis-free investigation. Analysis of pooled specimens resulted in the production of a “fingerprint” made of 44 proteins for NS/HS; 17 for COPD and 15 for the group of AATD subjects. Several inflammatory cytokines (IL-1α, IL-1β, IL-2; IL-12, α and β subunits, IL-15, interferon α and γ, tumor necrosis factor α); Type I and II cytokeratins; two SP-A isoforms; Calgranulin A and B and α1-antitrypsin were detected and validated through the use of surface enhanced laser-desorption ionization mass spectrometry (SELDI-MS) and/or by Western blot (WB) analysis. These results are the prelude of quantitative studies aimed at identifying which of these proteins hold promise as identifiers of differences that could distinguish healthy subjects from patients.

Asthmatic cough and airway oxidative stress

The mechanisms of cough in asthma are unclear. Asthma is associated with an oxidative stress. Many reactive oxygen species sensitize or activate sensory C-fibers which are capable to induce cough. It was hypothesized that oxidative stress in the airways might contribute to the cough severity in asthma. Exhaled breath condensate samples were collected in ten healthy and 26 asthmatic subjects. The concentration of 8-isoprostane was measured. In addition, the subjects filled in Leicester Cough Questionnaire and underwent cough provocation tests with dry air hyperpnoea and hypertonic saline, among other measurements. Among the asthmatic subjects, high 8-isoprostane was associated with severe cough response to hyperpnoea (p=0.001), low Leicester Cough Questionnaire values (indicating severe subjective cough, p=0.02), and usage of combination asthma drugs (p=0.03-0.04). However, the 8-isoprostane concentrations did not differ significantly between the healthy and the asthmatic subjects. Airway oxidative stress may be associated with experienced cough severity and measured cough sensitivity in asthma.

Irritant-induced airway disorders

Thousands of persons experience accidental high-level irritant exposures each year but most recover and few die. Irritants function differently than allergens because their actions proceed nonspecifically and by nonimmunologic mechanisms. For some individuals, the consequence of a single massive exposure to an irritant, gas, vapor or fume is persistent airway hyperresponsiveness and the clinical picture of asthma, referred to as reactive airways dysfunction syndrome (RADS). Repeated irritant exposures may lead to chronic cough and continual airway hyperresponsiveness. Cases of asthma attributed to repeated irritant-exposures may be the result of genetic and/or host factors.

Antimicrobial peptides and periodontal disease

AIMS

The goal of this review is to identify the antimicrobial proteins in the oral fluids, saliva and gingival crevicular fluid and identify functional families and candidates for antibacterial treatment.

RESULTS

Periodontal biofilms initiate a cascade of inflammatory and immune processes that lead to the destruction of gingival tissues and ultimately alveolar bone loss and tooth loss. Treatment of periodontal disease with conventional antibiotics does not appear to be effective in the absence of mechanical debridement. An alternative treatment may be found in antimicrobial peptides and proteins, which can be bactericidal and anti-inflammatory and block the inflammatory effects of bacterial toxins. The peptides have co-evolved with oral bacteria, which have not developed significant peptide resistance. Over 45 antibacterial proteins are found in human saliva and gingival crevicular fluid. The proteins and peptides belong to several different functional families and offer broad protection from invading microbes. Several antimicrobial peptides and proteins (AMPs) serve as templates for the development of therapeutic peptides and peptide mimetics, although to date none have demonstrated efficacy in human trials.

CONCLUSIONS

Existing and newly identified AMPs may be developed for therapeutic use in periodontal disease or can serve as templates for peptide and peptide mimetics with improved therapeutic indices.

Biomarkers of immunotoxicity for environmental and public health research

The immune response plays an important role in the pathophysiology of numerous diseases including asthma, autoimmunity and cancer. Application of biomarkers of immunotoxicity in epidemiology studies and human clinical trials can improve our understanding of the mechanisms that underlie the associations between environmental exposures and development of these immune-mediated diseases. Immunological biomarkers currently used in environmental health studies include detection of key components of innate and adaptive immunity (e.g., complement, immunoglobulin and cell subsets) as well as functional responses and activation of key immune cells. The use of high-throughput assays, including flow cytometry, Luminex, and Multi-spot cytokine detection methods can further provide quantitative analysis of immune effects. Due to the complexity and redundancy of the immune response, an integrated assessment of several components of the immune responses is needed. The rapidly expanding field of immunoinformatics will also aid in the synthesis of the vast amount of data being generated. This review discusses and provides examples of how the identification and development of immunological biomarkers for use in studies of environmental exposures and immune-mediated disorders can be achieved.

Biomarkers in asthma and allergic rhinitis

A biological marker (biomarker) is a physical sign or laboratory measurement that can serve as an indicator of biological or pathophysiological processes or as a response to a therapeutic intervention. An applicable biomarker possesses the characteristics of clinical relevance (sensitivity and specificity for the disease) and is responsive to treatment effects, in combination with simplicity, reliability and repeatability of the sampling technique. Presently, there are several biomarkers for asthma and allergic rhinitis that can be obtained by non-invasive or semi-invasive airway sampling methods meeting at least some of these criteria. In clinical practice, such biomarkers can provide complementary information to conventional disease markers, including clinical signs, spirometry and PC(20)methacholine or histamine. Consequently, biomarkers can aid to establish the diagnosis, in staging and monitoring of the disease activity/progression or in predicting or monitoring of a treatment response. Especially in (young) children, reliable, non-invasive biomarkers would be valuable. Apart from diagnostic purposes, biomarkers can also be used as (surrogate) markers to predict a (novel) drug's efficacy in target populations. Therefore, biomarkers are increasingly applied in early drug development. When implementing biomarkers in clinical practice or trials of asthma and allergic rhinitis, it is important to consider the heterogeneous nature of the inflammatory response which should direct the selection of adequate biomarkers. Some biomarker sampling techniques await further development and/or validation, and should therefore be applied as a "back up" of established biomarkers or methods. In addition, some biomarkers or sampling techniques are less suitable for (very young) children. Hence, on a case by case basis, a decision needs to be made what biomarker is adequate for the target population or purpose pursued. Future development of more sophisticated sampling methods and quantification techniques, such as--omics and biomedical imaging, will enable detection of adequate biomarkers for both clinical and research applications.

Evaluating cytokines in immunotoxicity testing

One of the most potentially useful tools in immunotoxicology is the assessment of cytokines, the proteins/peptides that are responsible for regulating a variety of processes including immunity, inflammation, apoptosis, and hematopoiesis. Cytokine production measurements offer an outstanding promise and may eventually substitute for other more laborious procedures. The particular profile of cytokine production may provide an important information regarding the nature of many immunotoxic responses.Recent expansion in the knowledge of cytokine biology and the realization that cytokines play a role in human diseases have created a need for the precise assessment and accurate interpretation of their presence and activity in the body fluids, tissues and cells. Proper evaluation of cytokines requires attention to several technical details. Multi-cytokine analysis still needs to be standardized in terms of optimum source for analysis, protocols and quality control issues, such as the use of reference standards and the expression of results.Important practical details and considerations will be discussed in this chapter, including the source of the sample to be tested (circulating fluids, or ex vivo/in vitro isolated cells), the potential effects of collection, processing, and storage of the results of the assays, as well as potential variables associated with the source material (matrix effects, relevance, inhibitory substances), and factors influencing the choice of assay used (bioassay, immunoassay, molecular biology technique, flow cytometry).

Leukotriene B4 contributes to exhaled breath condensate and sputum neutrophil chemotaxis in COPD

BACKGROUND

Neutrophils have been implicated in the pathogenesis of COPD. Several chemoattractants for neutrophils have been measured in samples of exhaled breath condensate (EBC) and induced sputum (IS) from patients with COPD. The aims of this study were to compare EBC and IS supernatant neutrophil chemotactic activity (NCA) from ex-smoking subjects with COPD and healthy ex-smokers, and to assess the contribution of leukotriene B(4) (LTB(4)) to this activity.

METHODS

Thirty-four subjects with COPD were compared to 24 control subjects. EBC and IS chemotactic activity for neutrophils was assessed by using Boyden microchambers. The chemotactic index was used to evaluate cell migration. LTB(4) was measured by a specific enzyme immunoassay. The contribution of LTB(4) to EBC and sputum neutrophil chemotaxis was assessed by an LTB(4) receptor antagonist (U-75302; Cayman Chemical Company; Ann Arbor, MI).

RESULTS

EBC and IS samples from both COPD patients and healthy subjects displayed significant NCA, but this activity was raised in COPD patients compared to healthy subjects. The chemotactic activity contained in sputum, however, failed to correlate with that in EBC. In COPD patients, there was a significant correlation between EBC NCA and sputum neutrophil counts. LTB(4) levels were raised in EBC samples, but not in sputum samples, from COPD subjects compared to those from healthy subjects. LTB(4) receptor antagonist concentrations (2.5 x 10(-4) mol/L) reduced by 44.6% and by 44.4%, respectively, the chemotactic activity contained in the EBC and sputum samples.

CONCLUSIONS

EBC and IS from COPD patients have a raised NCA to which LTB(4) contributes.

Incense smoke: clinical, structural and molecular effects on airway disease

In Asian countries where the Buddhism and Taoism are mainstream religions, incense burning is a daily practice. A typical composition of stick incense consists of 21% (by weight) of herbal and wood powder, 35% of fragrance material, 11% of adhesive powder, and 33% of bamboo stick. Incense smoke (fumes) contains particulate matter (PM), gas products and many organic compounds. On average, incense burning produces particulates greater than 45 mg/g burned as compared to 10 mg/g burned for cigarettes. The gas products from burning incense include CO, CO₂, NO₂, SO₂, and others. Incense burning also produces volatile organic compounds, such as benzene, toluene, and xylenes, as well as aldehydes and polycyclic aromatic hydrocarbons (PAHs). The air pollution in and around various temples has been documented to have harmful effects on health. When incense smoke pollutants are inhaled, they cause respiratory system dysfunction. Incense smoke is a risk factor for elevated cord blood IgE levels and has been indicated to cause allergic contact dermatitis. Incense smoke also has been associated with neoplasm and extracts of particulate matter from incense smoke are found to be mutagenic in the Ames Salmonella test with TA98 and activation. In order to prevent airway disease and other health problem, it is advisable that people should reduce the exposure time when they worship at the temple with heavy incense smokes, and ventilate their house when they burn incense at home.

The value of sputum 8-isoprostane in detecting oxidative stress in mild asthma

BACKGROUND

Exhaled nitric oxide and induced sputum eosinophils are well established as direct markers of inflammation/oxidative stress in asthma. Recently, it has been proposed that sputum 8-isoprostane concentrations may present a reliable index for measuring oxidative stress in asthmatic patients. We assessed the value of sputum 8-isoprostane in mild asthma in children and adolescents.

METHODS

Patients with newly diagnosed asthma (children, n = 23; adults, n = 14) and age-matched healthy controls (children, n = 13; adults, n = 15) were studied. Lung function was measured by spirometry, sputum was induced by hypertonic saline, and fractional exhaled nitric oxide (FeNO) was measured with standard methods. Cell differential counts were obtained from sputum slides and the concentration of 8-isoprostane was measured with an enzyme immunoassay from sputum supernatants.

RESULTS

High-quality sputum specimens could be obtained from 10 children and 10 adults, and the sputum analyses were conducted only for the representative specimens. Asthmatics had increased FeNO (children 35.5 vs. 11.9 ppb; adults 81.1 vs. 16.6 ppb; p < 0.001) and sputum eosinophils (children 2.4% vs. 1.4%; adults 10.4% vs. 0.2%; p = 0.005) compared to healthy controls. There was a significant correlation between FeNO and eosinophils (R = 0.65; p < 0.0001). Sputum 8-isoprostane was not elevated in asthmatics compared to healthy subjects (children 81.1 vs. 89.9 and adults 76.9 vs. 73.4 pg/mL) and did not correlate with lung function or other measurements of airway inflammation. However, increased 8-isoprostane levels were detected in patients with chronic obstructive pulmonary disease (n = 11, 184.7 pg/mL, used as controls for assays).

CONCLUSIONS

In agreement with earlier studies, FeNo is sensitive in detecting oxidative/nitrosative stress in asthmatic airways. However, our results suggest that 8-isoprostane may not be sensitive in reflecting oxidant burden in mild asthma.

Influence of condensing equipment and temperature on exhaled breath condensate pH, total protein and leukotriene concentrations

BACKGROUND

Exhaled breath condensate analysis is an attractive but still not fully standardised method for investigating airway pathology. Adherence of biomarkers to various condensing surfaces and changes in condensing temperature has been considered to be responsible for the variability of the results. Our aims were to compare the efficacy of different types of condensers and to test the influence of condensing temperature on condensate composition.

METHODS

Breath condensates from 12 healthy persons were collected in two settings: (1) by using three condensers of different type (EcoScreen, R-Tube, Anacon) and (2) by using R-Tube condenser either cooled to -20 or -70 degrees C. Condensate pH at standardised CO(2) level was determined; protein content was measured by the Bradford method and leukotrienes by EIA.

RESULTS

Breath condensates collected using EcoScreen were more alkaline (6.45+/-0.20 vs. 6.19+/-0.23, p<0.05 and 6.10+/-0.26, p<0.001) and contained more protein (3.89+/-2.03 vs. 2.65+/-1.98, n.s. and 1.88+/-1.99 microg/ml, p<0.004) as compared to the other devices. Only parameters obtained with R-Tube and Anacon correlated. Condensing temperature affected condensate pH (5.99+/-0.20 at -20 degrees C and 5.82+/-0.07 at -70 degrees C, p<0.05) but not protein content. Leukotriene B(4) was not found in any sample and cysteinyl-leukotriene was not found in condensates collected with R-Tube or Anacon.

CONCLUSION

Condenser type influences sample pH, total protein content and cysteinyl-leukotriene concentration. Condensing temperature influences condensate pH but not total protein content. These results suggest that adherence of the biomarkers to condenser surface and condensing temperature may play a role but does not fully explain the variability of EBC biomarker levels.

Airway biomarkers of the oxidant burden in asthma and chronic obstructive pulmonary disease: current and future perspectives

The pathogenesis of asthma and chronic obstructive pulmonary disease (COPD) has been claimed to be attributable to increased systemic and local oxidative stress. Detection of the oxidant burden and evaluation of their progression and phenotypes by oxidant biomarkers have proved challenging and difficult. A large number of asthmatics are cigarette smokers and smoke itself contains oxidants complicating further the use of oxidant biomarkers. One of the most widely used oxidant markers in asthma is exhaled nitric oxide (NO), which plays an important role in the pathogenesis of asthma and disease monitoring. Another oxidant marker that has been widely investigated in COPD is 8-isoprostane, but it is probably not capable of differentiating asthma from COPD, or even sensitive in the early assessment of these diseases. None of the current biomarkers have been shown to be better than exhaled NO in asthma. There is a need to identify new biomarkers for obstructive airway diseases, especially their differential diagnosis. A comprehensive evaluation of oxidant markers and their combinations will be presented in this review. In brief, it seems that additional analyses utilizing powerful tools such as genomics, metabolomics, lipidomics, and proteomics will be required to improve the specificity and sensitivity of the next generation of biomarkers.

Possible Impact of Salivary Influence on Cytokine Analysis in Exhaled Breath Condensate

Background

Exhaled breath condensate (EBC) is thought to contain substances of the lower airway epithelial lining fluid (ELF) aerosolized by turbulent flow. However, contamination by saliva may affect the EBC when collected orally.

Objective

The purpose of this study was to compare the cytokine expression levels in EBC with those in saliva, and to clarify the influence of saliva on cytokine measurements of EBC.

Methods

EBC and saliva samples were obtained from 10 adult subjects with stable asthma. To estimate differences in the contents of substances between EBC and saliva, the total protein concentration of each sample was measured. Further, we also measured the total protein concentration of ELF obtained from another patient group with suspected lung cancer using a micro sampling probe during bronchoscopic examination and roughly estimated the dilution of EBC by comparing the total protein concentration of EBC and ELF from those two patient groups. The cytokine expression levels of EBC and saliva from asthmatic group were assessed by a cytokine protein array.

Results

The mean total protein concentrations in EBC, saliva and ELF were 4.6 μg/ml, 2,398 μg/ml and 14,111 μg/ml, respectively. The dilution of EBC could be estimated as 1:3000. Forty cytokines were analyzed by a cytokine protein array and each cytokine expression level of EBC was found to be different from that of saliva. Corrected by the total protein concentration, all cytokine expression levels of EBC were significantly higher than those of saliva.

Conclusion

These results suggest that the salivary influence on the cytokine assessment in EBC may be negligible.

Cytokines and other immunological biomarkers in children's environmental health studies

Environmental exposures (e.g. pesticides, air pollution, and environmental tobacco smoke) during prenatal and early postnatal development have been linked to a growing number of childhood diseases including allergic disorders and leukemia. Because the immune response plays a critical role in each of these diseases, it is important to study the effects of toxicants on the developing immune system. Children's unique susceptibility to environmental toxicants has become an important focus of the field of immunotoxicology and the use of immune biomarkers in molecular epidemiology of children's environmental health is a rapidly expanding field of research. In this review, we discuss how markers of immune status and immunotoxicity are being applied to pediatric studies, with a specific focus on the various methods used to analyze T-helper-1/2 (Th1/Th2) cytokine profiles. Furthermore, we review recent data on the effects of children's environmental exposures to volatile organic compounds, metals, and pesticides on Th1/Th2 cytokine profiles and the associations of Th1/Th2 profiles with adverse health outcomes such as pediatric respiratory diseases, allergies, cancer and diabetes. Although cytokine profiles are increasingly used in children's studies, there is still a need to acquire distribution data for different ages and ethnic groups of healthy children. These data will contribute to the validation and standardization of cytokine biomarkers for future studies. Application of immunological markers in epidemiological studies will improve the understanding of mechanisms that underlie associations between environmental exposures and immune-mediated disorders.

Granulocyte Chemotactic Activity in Exhaled Breath Condensate of Healthy Subjects and Patients With COPD

BACKGROUND

Several chemoattractants have been measured in exhaled breath condensate (EBC) from patients with COPD. The aim of this study was to compare the eosinophil and neutrophil chemotactic activity contained in EBC from healthy subjects and patients with COPD.

METHODS

EBC collected using a commercially available condenser (EcoScreen; Erich Jaeger Viasys; Hoechberg, Germany) was compared in 45 COPD patients and 65 healthy subjects. EBC chemotactic activity for eosinophils and neutrophils was assessed using microchambers (Boyden; Neuro Probe; Cabin John, MD). Chemotactic index (CI) was used to evaluate cell migration.

RESULTS

EBC from patients with COPD (CI, 2.21 +/- 0.16 [mean +/- SEM]) and healthy subjects (CI, 1.67 +/- 0.11) displayed significant neutrophil chemotactic activity (p < 0.0001 for both), which was however higher in patients with COPD (p < 0.001). Healthy smokers had a significantly raised CI for neutrophils by comparison with healthy nonsmokers (p < 0.01) and ex-smokers (p < 0.05). Likewise, current COPD smokers tended to have greater neutrophil CI than COPD who stopped smoking (p = 0.08). COPD ex-smokers had raised chemotactic activity by comparison with healthy ex-smokers (p < 0.05). Anti-interleukin-8 (10(-6) g/mL) antibodies reduced neutrophil chemotactic activity by 35.2% (p < 0.05). EBC also contained significant eosinophil chemotactic activity in healthy subjects (CI, 1.68 +/- 0.09; p < 0.0001) and patients with COPD (CI, 1.23 +/- 0.07; p < 0.01), with a significantly lower CI in patients with COPD as compared to healthy subjects (p < 0.001). Smoking did not influence eosinophil chemotactic activity in healthy subjects or patients with COPD.

CONCLUSIONS

Current smoking favors neutrophil chemotactic activity. As compared to healthy subjects, EBC from patients with COPD displays a skewed chemotactic activity toward neutrophils vs eosinophils.

Saliva specimen: a new laboratory tool for diagnostic and basic investigation

The assay of saliva is an increasing area of research with implications for basic and clinical purposes. Although this biological fluid is easy to manipulate and collect, careful attention must be directed to limit variation in specimen integrity. Recently, the use of saliva has provided a substantial addition to the diagnostic armamentarium as an investigative tool for disease processes and disorders. In addition to its oral indications, the analysis of saliva provides important information about the functioning of various organs within the body. In this respect, endocrine research certainly occupies a central role. The present review considers the laboratory aspects of salivary assays with respect to the different analytes including ions, drugs and various non-protein/protein compounds such as hormones and immunoglobulins. This review also examines the consequences of preanalytical variation with respect to collection strategy and subsequent storage conditions. It is likely that the use of saliva in assays will continue to expand thus providing a new instrument of investigation for physiologic as well as pathophysiologic states.

An investigation of airway acidification in asthma using induced sputum: a study of feasibility and correlation

RATIONALE

Acidification of the airways seems to be involved in asthma pathophysiology, but its assessment might be difficult.

OBJECTIVES

The aim of our study is to assess the feasibility and validity of airway acidification measurement by induced sputum and its clinical significance in asthma.

METHODS

Induced-sputum samples were obtained in 57 outpatients with asthma. The between-sample repeatability after 48 hours was measured in an independent population of 14 patients with asthma. pH was measured using a pH meter. The control of asthma was established by the Asthma Control Questionnaire.

MEASUREMENTS AND MAIN RESULTS

The pH measurement was feasible in all samples and repeatable both within (intraclass correlation coefficient [ICC], 0.96) and between samples (ICC, 0.621). The mean pH was significantly different between healthy subjects and patients with asthma, including in those with controlled (mean pH: 7.54 in healthy subjects vs. 7.28 in subjects with controlled asthma; p = 0.0105) and uncontrolled disease (mean pH: 7.54 in healthy subjects vs. 7.06 in subjects with uncontrolled disease; p < 0.0001), and between patients with stable asthma and those with poorly controlled asthma (7.28 vs. 7.06, respectively; p = 0.0134). The validity of the method was assessed with the receiver operating characteristic curves and induced-sputum lower pH values (with a cutoff value of 7.3; sensitivity, 72.1%; specificity, 100%).

CONCLUSIONS

Patients with asthma show lower pH than healthy subjects. Patients with poorly controlled asthma seem to have the lowest induced-sputum pH, independent of the GINA (Global Initiative for Asthma) severity level. In conclusion, induced sputum is a feasible, repeatable, noninvasive method to measure airway pH. The pH in induced sputum may reflect a different aspect of asthma from sputum eosinophils and be related to different pathophysiologic factors.

Measurement of cytokines in sweat patches and plasma in healthy women: validation in a controlled study

Cytokines have been detected by ELISA in a variety of body fluids. Recycling immunoaffinity chromatography (RIC) coupled with laser-induced fluorescence detection is a highly sensitive and specific method, which allows simultaneous measurements of many analytes in small volumes of biological fluids. This method has been applied to plasma, cervical secretions and other body fluids, but has not previously been applied to sweat. The aim of this study was to validate the RIC methodology in sweat for measurements of IL-1alpha, IL-1beta, IL-6, TNF-alpha, IL-8 and TGF-beta. Two sweat patches were applied for 24 h on the torso, and blood was collected at one time point during this period in nine healthy women. Cytokines were measured in paired samples of plasma and sweat. Cytokines were detected in sweat in similar concentrations to plasma. Linear regression analysis confirmed that sweat levels of these cytokines accounted for a large percentages of variance in plasma levels: IL-1alpha (R2 = 0.70, p = 0.005), IL-1beta (R2 = 0.79, p = 0.003), IL-6 (R2 = 0.52, p = 0.03), TNF-alpha (R2 = 0.95, p < 0.0001), IL-8 (R2 = 0.81, p = 0.001) and TGF-beta (R2 = 0.94, p = 0.0003). These findings indicate that cytokine levels measured in sweat are informative of circulating levels and that sweat patches combined with RIC represents a viable non-invasive method to measure cytokines in ambulatory settings over time. This method is unobtrusive and requires minimal active compliance on the part of the subjects being studied, without pain or stress. This approach can open a new generation of studies to address the effects of environmental factors on immune responses in a wide range of different settings.

The role of bacteria in airway inflammation in exacerbations of chronic obstructive pulmonary disease

PURPOSE OF REVIEW

Bacteria cause approximately half of all chronic obstructive pulmonary disease exacerbations. The purpose of this review is to evaluate the status of research on the role of bacteria in airway inflammation during exacerbations and the mechanisms by which bacterial antigens induce inflammation.

RECENT FINDINGS

Bacteria in the airways of adults with chronic obstructive pulmonary disease release antigens including endotoxin, peptidoglycan fragments, lipoproteins, and other molecules into the airways. These bacterial antigens induce potent inflammatory effects in the airways. Bacterial exacerbations are associated with systemic inflammation. Studies of Haemophilus influenzae, the most common bacterial cause of exacerbations, reveal that strains associated with exacerbations induce more inflammation compared to colonizing strains. H. influenzae antigens induce production of interleukin-8 and tumor necrosis factor-alpha, activate Toll-like 2 receptors, activate NFkappaB and p38 mitogen-activated protein signaling pathways, and have other inflammatory effects.

SUMMARY

Research on the role of bacteria in causing inflammation in chronic obstructive pulmonary disease has been neglected for decades. Research should be directed at further evaluating the role of bacterial antigens in airway inflammation. Reducing or modulating bacterial infection of the airways in chronic obstructive pulmonary disease has the potential to reduce airway inflammation by eliminating an important inciting cause.