A comparison of serum haptoglobin levels between acute exacerbation and clinical remission in asthma

Oncostatin M expression induced by bacterial triggers drives airway inflammatory and mucus secretion in severe asthma

[Figure: see text].

Urinary polycyclic aromatic hydrocarbon metabolites and adult asthma: a case-control study

Polycyclic aromatic hydrocarbons (PAHs) exposure was reported to be associated with childhood asthma. However, the quantitative relationship between PAHs exposure and adult asthma and possible inflammatory pathways are less clear. We aimed to investigate potential associations between urinary PAHs metabolites and adult asthma. We enrolled 507 adult asthma cases and 536 matched controls. The concentrations of 12 urinary PAHs metabolites and plasma cytokines of interleukin (IL)-9 and eotaxin were measured. Potential associations between urinary PAHs metabolites and adult asthma were analyzed by logistic regression. The relationships between urinary PAHs metabolites and plasma cytokines were determined by generalized linear regression. After adjusted for covariates, each 1-unit-increase in natural log-transformed concentrations of 2-hydroxyfluorene (2-OHFLU), 4- hydroxyphenanthrene (4-OHPHE), 1-OHPHE, 2-OHPHE, 1-Hydroxypyrene (1-OHPYR) and ∑OH-PAHs were significantly associated with elevated risk of adult asthma with odds ratios of 2.04, 2.38, 2.04, 1.26, 2.35 and 1.34, respectively. And the associations were more pronounced in the subjects who were female, younger than 45 years, smoker and had history of occupational dust exposure. No associations were observed between urinary PAHs metabolites levels and expressions of IL-9 and eotaxin. Our results demonstrated that elevated urinary PAHs metabolites levels were associated with increased risk of asthma in adults.

Pulmonary Remodeling in Equine Asthma: What Do We Know about Mediators of Inflammation in the Horse?

Equine inflammatory airway disease (IAD) and recurrent airway obstruction (RAO) represent a spectrum of chronic inflammatory disease of the airways in horses resembling human asthma in many aspects. Therefore, both are now described as severity grades of equine asthma. Increasing evidence in horses and humans suggests that local pulmonary inflammation is influenced by systemic inflammatory processes and the other way around. Inflammation, coagulation, and fibrinolysis as well as extracellular remodeling show close interactions. Cytology of bronchoalveolar lavage fluid and tracheal wash is commonly used to evaluate the severity of local inflammation in the lung. Other mediators of inflammation, like interleukins involved in the chemotaxis of neutrophils, have been studied. Chronic obstructive pneumopathies lead to remodeling of bronchial walls and lung parenchyma, ultimately causing fibrosis. Matrix metalloproteinases (MMPs) are discussed as the most important proteolytic enzymes during remodeling in human medicine and increasing evidence exists for the horse as well. A systemic involvement has been shown for severe equine asthma by increased acute phase proteins like serum amyloid A and haptoglobin in peripheral blood during exacerbation. Studies focusing on these and further possible inflammatory markers for chronic respiratory disease in the horse are discussed in this review of the literature.

Heaves, an asthma-like disease of horses

Animal models have been developed to investigate specific components of asthmatic airway inflammation, hyper-responsiveness or remodelling. However, all of these aspects are rarely observed in the same animal. Heaves is a naturally occurring disease of horses that combines these features. It is characterized by stable dust-induced inflammation, bronchospasm and remodelling. The evaluation of horses during well-controlled natural antigen exposure and avoidance in experimental settings allows the study of disease mechanisms in the asymptomatic and symptomatic stages, an approach rarely feasible in humans. Also, the disease can be followed over several years to observe the cumulative effect of repeated episodes of clinical exacerbation or to evaluate long-term treatment, contrasting most murine asthma models. This model has shown complex gene and environment interactions, the involvement of both innate and adaptive responses to inflammation, and the contribution of bronchospasm and tissue remodelling to airway obstruction, all occurring in a natural setting. Similarities with the human asthmatic airways are well described and the model is currently being used to evaluate airway remodelling and its reversibility in ways that are not possible in people for ethical reasons. Tools including antibodies, recombinant proteins or gene arrays, as well as methods for sampling tissues and assessing lung function in the horse are constantly evolving to facilitate the study of this animal model. Research perspectives that can be relevant to asthma include the role of neutrophils in airway inflammation and their response to corticosteroids, systemic response to pulmonary inflammation, and maintaining athletic capacities with early intervention.

Relationship between group-specific component protein and the development of asthma

RATIONALE

Airway inflammation and remodeling during asthma are attributed to the altered expression of biologically relevant proteins.

OBJECTIVES

To search for asthma-specific proteins in bronchoalveolar lavage fluid (BAL) from individuals with asthma and to validate the identified proteins in an experimental model of asthma.

METHODS

Liquid chromatography-tandem mass spectrometry was performed to identify proteins in BAL fluid found by two dimensional electrophoresis (2DE) to be differentially expressed in subjects with asthma versus control subjects. Group-specific component (Gc) and mRNA levels were measured using an ELISA, Western blots, and PCR. A neutralization study using an antibody against Gc protein was performed in an experimental asthma model.

MEASUREMENTS AND MAIN RESULTS

Based on 2DE, 15 proteins were significantly up-regulated or down-regulated in eight subjects with asthma compared with eight control subjects. The protein levels of Gc, hemopexin, and haptoglobin-b were increased, whereas the a1- antitrypsin and glutathione S-transferase levels were decreased in subjects with asthma. The Gc concentration in BAL fluid was significantly elevated in 67 subjects with asthma compared with that in 22 control subjects (P < 0.009). The Gc was significantly correlated with the neutrophil percentage in BAL fluid of subjects with asthma (P = 0.001). Gc mRNA and protein levels were higher in ovalbumin-sensitized/ challenged asthma mice than in sham-treated mice. Gc protein were expressed on alveolar macrophages and on epithelial cells. Treatment with an anti-Gc antibody dose-dependently reduced the ovalbumin sensitization/challenge-induced enhancement of airway hyperreactivity, airway inflammation, goblet cell hyperplasia,and levels of eotaxin, interleukin-4, -5, and -13, and interferon-g.

CONCLUSIONS

Gc may be involved in the development of asthma, and the neutralization of Gc protein could be a therapeutic strategy for asthma.

Identification of novel diagnostic biomarkers for asthma and chronic obstructive pulmonary disease

RATIONALE

Proteomics may identify a useful panel of biomarkers for identification of asthma and chronic obstructive pulmonary disease (COPD).

OBJECTIVES

To conduct an unsupervised analysis of peripheral blood proteins in well-characterized subjects with asthma and COPD, and identify and validate a biomarker panel for disease discrimination.

METHODS

Two-dimensional difference gel electrophoresis was used to separate plasma proteins from healthy control subjects, stable patients with asthma, and individuals with COPD. Candidate protein markers were identified by matrix assisted laser desorption ionization time of flight mass spectrometry and subsequently validated in two populations via immunoassay. A panel of four biomarkers was selected and their ability to distinguish between groups was assessed in isolation and in combination in two separate validation populations.

MEASUREMENTS AND MAIN RESULTS

Seventy-two protein spots displayed significantly different expression levels between the three subject groupings (P < 0.05). Fifty-eight were positively identified, representing 20 unique proteins. A panel of four biomarkers (α(2)-macroglobulin, haptoglobin, ceruloplasmin, and hemopexin) was able to discriminate with statistical significance between the clinical groups of patients with asthma, patients with COPD, and control subjects, and these results were confirmed in a second clinical population of older adults with airflow obstruction.

CONCLUSIONS

Proteomics has identified novel biomarkers for asthma and COPD, and shown that the iron metabolism pathways and acute-phase response may be involved in the pathogenesis of airway disease. The panel of peripheral blood biomarkers has the potential to become an extremely useful addition to the clinical diagnosis and management of respiratory disease.

Changes in serum haptoglobin level after allergen challenge test in asthmatic children

Bronchial asthma is characterized by airway inflammation, which underlies the phenomenon of bronchial hyperresponsiveness. Previous studies have shown that this correlates with the serum concentration of haptoglobin. The occurrence of the late asthmatic response (LAR) after an allergen challenge test is associated with airway inflammation. The objectives of this study were to examine serum levels of haptoglobin during the 24 h after allergen challenge and to compare changes between the subjects with and without LAR. We studied two groups of children with perennial asthma who developed the early asthmatic response (EAR) only (group I: n = 14), and EAR but also LAR (group II: n = 14) after an allergen (Dermatophagoides pteronyssinus) challenge test. Serum concentrations of haptoglobin were measured at baseline, at EAR, and at 2 h (recovery), 8 h (LAR), and 24 h after the challenge. Baseline levels were similar in the two groups (group I: 128 +/- 57 mg/dl; group II: 129 +/- 50 mg/dl). In group I, there was no significant change in the level at any time point; in contrast, the subjects in group II showed a relative fall (92 +/- 40 mg/dl) at 8 h, and an increase (161 +/- 79 mg/dl) at 24 h after the challenge. Our results indicate that the serum concentration of haptoglobin decreases at the time of LAR and is subsequently replenished during the ensuing time. Although further studies are needed, we think that haptoglobin may be inflused into the airways during the inflammatory process associated with LAR, and that this may be followed by "overshooting" production.

Serum eosinophil cationic protein levels and bronchodilator responses at acute asthma exacerbation

BACKGROUND

Serum levels of eosinophil cationic protein are an indirect measure of airway inflammation in asthma. It is proposed that the extent to which broncho-constriction or airway inflammation contributes to airflow obstruction in acute asthma may determine responsiveness to bronchodilator therapy.

OBJECTIVE

To test the hypothesis that subjects with acute asthma exacerbations who respond poorly to inhaled bronchodilator treatment may have more marked airway inflammation than those who respond well to identical therapy.

METHODS

Forty-eight asthmatic children who visited the emergency room due to acute exacerbations were studied. Serum levels of eosinophil cationic protein were measured at the time of acute exacerbations and of clinical remissions. At acute exacerbation, FEV1 was assessed before and after the administration of aerosolized salbutamol.

RESULTS

The mean serum level of eosinophil cationic protein at acute exacerbation (41.1 +/- 12.8 micrograms/L) was significantly higher (P < .01) than that at clinical remission (30.0 +/- 8.5 micrograms/L) in the study population. The level at acute exacerbation was even higher in group A (n = 18: postbronchodilator FEV1 < 75% predicted) than in group B (n = 30: postbronchodilator FEV1 > or = 75% predicted), whereas both groups showed similar levels at clinical remission. The level at acute exacerbation correlated positively with severity of exacerbation (r = .47, P < .01) and negatively with bronchodilator responses (r = -.56, P < .01). This negative correlation was valid among subjects with a similar degree of exacerbation.

CONCLUSION

A higher level of eosinophil cationic protein at acute asthma exacerbation was associated not only with more severe exacerbation but also with a lower degree of bronchodilator responsiveness. This suggests that degree of airway inflammation may be one determinant of degree of responsiveness to initial bronchodilator therapy at acute asthma exacerbation.