The effect of lower airway inflammation on inflammatory cytokine gene expression in bronchoalveolar lavage fluid and whole blood in racing Thoroughbreds.

BACKGROUND: Immunological mechanisms involved in the pathogenesis of mild to moderate equine asthma (MEA) are not completely understood. There are limited data on bronchoalveolar lavage fluid (BALF) and blood inflammatory cytokine profiles in racehorses with MEA, and the effect of racing on inflammatory cytokines is unknown. HYPOTHESIS/OBJECTIVES: We hypothesized that inflammatory cytokine gene expression in BALF and resting blood would be higher in racehorses with lower airway inflammation compared to healthy controls, and that gene expression in blood collected immediately post-race would be increased compared to resting blood in racehorses with lower airway inflammation. ANIMALS: 38 racing Thoroughbreds (samples: 30 resting blood, 22 post-race BALF, 41 post-race blood). METHODS: Prospective observational study. Inflammatory cytokine gene expression was determined in resting blood, post-race BALF and post-race blood from racehorses with lower airway inflammation and controls. RESULTS: Lower airway inflammation was diagnosed in 79 % of racehorses (23 % neutrophilic, 67 % mastocytic, and 10 % mixed). There was no difference in gene expression in BALF or resting blood between racehorses with lower airway inflammation and controls. IL-8 gene expression was higher in post-race blood compared to resting peripheral blood, regardless of disease (p = 0052). BALF neutrophil proportions increased with increasing IL-1ß gene expression in all sample types (p = 0.0025). BALF mast cell proportions increased with increasing TNF-α gene expression in post-race blood (p = 0.015). CONCLUSIONS AND CLINICAL IMPORTANCE: Lower airway inflammation was common in a population of racehorses without respiratory signs or exercise intolerance. Exercise alone increased peripheral blood IL-8 gene expression. Inflammatory cytokine gene expression was not increased in BALF or resting blood in horses with subclinical lower airway inflammation, precluding its diagnostic utility in clinical practice.

Influence of polymorphisms of the beta-2 adrenergic receptor on the presence of exercise-induced bronchospasm in adolescents / Influência dos polimorfismos no receptor beta 2 adrenérgico na presença de broncoespasmo induzido pelo exercício em adolescentes

To determine the influence of polymorphisms of the beta-2 adrenergic receptor (ADRB2) in triggering exercise-induced bronchospasm (EIB) in adolescents. Methods: The subjects were divided into two groups: present EIB (EIB+) (n=45) and absent EIB (EIB−) (n=115). The bronchial provocation test with exercise was performed with a protocol that consisted of walking/running for at least eight minutes at high intensity, i.e., >85% of maximum heart rate, considering EIB+ as a 10% decrease in forced expiratory volume in one second (FEV1). The genotyping of the ADRB2 gene was performed by the Taqman method, using the Step One Plus system. Independent t-test, Mann–Whitney and Chi-square tests, as well as Spearman's correlation coefficient were used for the statistical analysis. Results: Age, body weight, height, FEV1, FVC and FEV1/FVC ratio were lower in the EIB+ group when compared to EIB− (p<0.05). There were no significant differences in the proportion of the allele at position 27 and Arg16Gly and Gln27Glu genotypes between the EIB+ and EIB− groups (p=0.26; p=0.97 and p=0.43, respectively). However, there was a trend toward statistical significance regarding the greater proportion of the Gly16 allele for the EIB+ when compared to the EIB− group (p=0.08). Conclusions: The presence of polymorphisms associated with the Glu27 allele and Arg16Gly and Gln27Glu genotypes had no influence on EIB. However, the statistical trend toward greater frequency of the Gly16 allele in individuals with EIB+ can be considered evidence of the influence of polymorphisms of the ADBR2 gene on EIB in adolescents.

Determinar a influência dos polimorfismos dos receptores adrenérgicos beta 2 (ADRB2) no desencadeamento de broncoespasmo induzido pelo exercício (BIE) em adolescentes. Métodos: Os sujeitos foram divididos em dois grupos: BIE presente (BIE+) (n=45) e BIE ausente (BIE−) (n=115). O teste de broncoprovocação com exercício foi feito com protocolo que consistiu em caminhar/correr durante no mínimo oito minutos em intensidade superior a 85% da frequência cardíaca máxima, considerando como BIE presente uma queda de 10% do volume expiratório forçado no primeiro segundo (VEF1). A genotipagem do gene ADRB2 foi feita pelo método Taqman por meio do aparelho Step One Plus. Para análise estatística usaram-se os testes t independente, U de Mann-Whitney, qui-quadrado e coeficiente de correlação de Spearman. Resultados: Idade, massa corporal, estatura, VEF1, CVF e relação VEF1/CVF foram menores no grupo BIE+ em comparação com o BIE− (p<0,05). Não houve diferenças significativas na proporção do alelo na posição 27 e dos genótipos Arg16Gly e Gln27Glu entre os grupos BIE+ e BIE− (p=0,26; p=0,97 e p=0,43, respectivamente). Entretanto, verificou-se uma tendência à significância estatística na maior proporção do alelo Gly16 para o grupo BIE+ comparado com o BIE− (p=0,08). Conclusões: A presença de polimorfismos associados ao alelo Glu27 e os genótipos Arg16Gly e Gln27Glu não influenciam no BIE. Porém, a tendência estatística observada para uma maior frequência do alelo Gly16 nos indivíduos com a presença de BIE pode ser considerado indício da influência de polimorfismos no gene ADBR2 no BIE em adolescentes.

[Influence of polymorphisms of the beta-2 adrenergic receptor on the presence of exercise-induced bronchospasm in adolescents]. / Influência dos polimorfismos no receptor beta 2 adrenérgico na presença de broncoespasmo induzido pelo exercício em adolescentes.

OBJECTIVE: To determine the influence of polymorphisms of the beta-2 adrenergic receptor (ADRB2) in triggering exercise-induced bronchospasm (EIB) in adolescents. METHODS: The subjects were divided into two groups: present EIB (EIB+) (n=45) and absent EIB (EIB-) (n=115). The bronchial provocation test with exercise was performed with a protocol that consisted of walking/running for at least eight minutes at high intensity, i.e., >85% of maximum heart rate, considering EIB+ as a 10% decrease in forced expiratory volume in one second (FEV1). The genotyping of the ADRB2 gene was performed by the Taqman method, using the Step One Plus system. Independent t-test, Mann-Whitney and Chi-square tests, as well as Spearman's correlation coefficient were used for the statistical analysis. RESULTS: Age, body weight, height, FEV1, FVC and FEV1/FVC ratio were lower in the EIB+ group when compared to EIB- (p<0.05). There were no significant differences in the proportion of the allele at position 27 and Arg16Gly and Gln27Glu genotypes between the EIB+ and EIB- groups (p=0.26; p=0.97 and p=0.43, respectively). However, there was a trend towards statistical significance regarding the greater proportion of the Gly16 allele for the EIB+ when compared to the EIB- group (p=0.08). CONCLUSIONS: The presence of polymorphisms associated with the Glu27 allele and Arg16Gly and Gln27Glu genotypes had no influence on EIB. However, the statistical trend towards greater frequency of the Gly16 allele in individuals with EIB+ can be considered evidence of the influence of polymorphisms of the ADBR2 gene on EIB in adolescents.

Prostaglandin E2 prevents hyperosmolar-induced human mast cell activation through prostanoid receptors EP2 and EP4.

BACKGROUND: Mast cells play a critical role in allergic and inflammatory diseases, including exercise-induced bronchoconstriction (EIB) in asthma. The mechanism underlying EIB is probably related to increased airway fluid osmolarity that activates mast cells to the release inflammatory mediators. These mediators then act on bronchial smooth muscle to cause bronchoconstriction. In parallel, protective substances such as prostaglandin E2 (PGE2) are probably also released and could explain the refractory period observed in patients with EIB. OBJECTIVE: This study aimed to evaluate the protective effect of PGE2 on osmotically activated mast cells, as a model of exercise-induced bronchoconstriction. METHODS: We used LAD2, HMC-1, CD34-positive, and human lung mast cell lines. Cells underwent a mannitol challenge, and the effects of PGE2 and prostanoid receptor (EP) antagonists for EP(1-4) were assayed on the activated mast cells. Beta-hexosaminidase release, protein phosphorylation, and calcium mobilization were assessed. RESULTS: Mannitol both induced mast cell degranulation and activated phosphatidyl inositide 3-kinase and mitogen-activated protein kinase (MAPK) pathways, thereby causing de novo eicosanoid and cytokine synthesis. The addition of PGE2 significantly reduced mannitol-induced degranulation through EP(2) and EP(4) receptors, as measured by beta-hexosaminidase release, and consequently calcium influx. Extracellular-signal-regulated kinase 1/2, c-Jun N-terminal kinase, and p38 phosphorylation were diminished when compared with mannitol activation alone. CONCLUSIONS: Our data show a protective role for the PGE2 receptors EP(2) and EP(4) following osmotic changes, through the reduction of human mast cell activity caused by calcium influx impairment and MAP kinase inhibition.

Loss of salmeterol bronchoprotection against exercise in relation to ADRB2 Arg16Gly polymorphism and exhaled nitric oxide.

RATIONALE: ß2-Agonists are the treatment of choice for exercise-induced bronchoconstriction (EIB) and act through specific receptors (ADRB2). Arg16Gly polymorphisms have been shown to affect responses to regular use of ß2-agonists. OBJECTIVES: To evaluate the influence of the Arg16Gly receptor polymorphism on salmeterol bronchoprotection in EIB and assess predictors of bronchoprotection. METHODS: A prospective, genotype-blinded, randomized trial was performed in 26 subjects (12 Arg16Arg and 14 Gly16Gly) with EIB who were not on controller therapy. Subjects were administered salmeterol, 50 µg twice a day for 2 weeks, and underwent an exercise challenge 9 hours after the first and last drug dose. In addition to genotype, FEV1, response to salmeterol, degree of EIB, and exhaled nitric oxide (FE(NO)) at baseline were examined for their association with loss of bronchoprotection (LOB). MEASUREMENTS AND MAIN RESULTS: The maximum exercise-induced FEV1 fall was 27.9 ± 1.4% during the run-in period, 8.1 ± 1.2% (70.3 ± 4.1% bronchoprotection) after the first salmeterol dose, and 22.8 ± 3.2% (18.9 ± 11.5% bronchoprotection) after 2 weeks of salmeterol (P = 0.0001). The Arg16Gly polymorphisms were not associated with the LOB in response to salmeterol. FeNO values at baseline were significantly related to the LOB (r = 0.47; P = 0.01). Mean change was a 74 ± 13% LOB in subjects with FE(NO) levels greater than 50 ppb and a 7 ± 16% gain in bronchoprotection in those with FE(NO) levels less than 25 ppb (P = 0.01). CONCLUSIONS: The LOB that occurs with chronic long-acting ß2-agonists use is not affected by ADRB2 Arg16Gly polymorphisms. High FE(NO) was associated with marked LOB. Use of long-acting ß2-agonists before achieving a reduction in FeNO may need to be avoided. Clinical trial registered with www.clinicaltrials.gov (NCT 00595361).

Regulation and function of epithelial secreted phospholipase A2 group X in asthma.

RATIONALE: Indirect airway hyperresponsiveness (AHR) is a fundamental feature of asthma that is manifest as exercise-induced bronchoconstriction (EIB). Secreted phospholipase A2 group X (sPLA2-X) plays a key role in regulating eicosanoid formation and the development of inflammation and AHR in murine models. OBJECTIVES: We sought to examine sPLA2-X in the airway epithelium and airway wall of patients with asthma, the relationship to AHR in humans, and the regulation and function of sPLA2-X within the epithelium. METHODS: We precisely phenotyped 34 patients with asthma (19 with and 15 without EIB) and 10 normal control subjects to examine in vivo differences in epithelial gene expression, quantitative morphometry of endobronchial biopsies, and levels of secreted protein. The regulation of sPLA2-X gene (PLA2G10) expression was examined in primary airway epithelial cell cultures. The function of epithelial sPLA2-X in eicosanoid formation was examined using PLA2 inhibitors and murine tracheal epithelial cells with Pla2g10 deletion. MEASUREMENTS AND MAIN RESULTS: We found that sPLA2-X protein is increased in the airways of patients with asthma and that epithelial-derived sPLA2-X may be increased in association with indirect AHR. The expression of sPLA2-X increases during in vitro epithelial differentiation; is regulated by inflammatory signals including tumor necrosis factor, IL-13, and IL-17; and is both secreted from the epithelium and directly participates in the release of arachidonic acid by epithelial cells. CONCLUSIONS: These data reveal a relationship between epithelial-derived sPLA2-X and indirect AHR in asthma and that sPLA2-X serves as an epithelial regulator of inflammatory eicosanoid formation. Therapies targeting epithelial sPLA2-X may be useful in asthma.

Association of IL-13 polymorphisms with leukotriene receptor antagonist drug responsiveness in Korean children with exercise-induced bronchoconstriction.

BACKGROUND: IL-13 is a pivotal cytokine in allergic inflammation and bronchial hyperresponsiveness, and is known to influence leukotriene levels. OBJECTIVE: We investigated whether IL-13 polymorphisms may be associated with clinical phenotypes and drug responsiveness to the leukotriene receptor antagonist (LTRA) in Korean asthmatic children with exercise-induced bronchoconstriction (EIB). METHODS: We enrolled 242 normal controls and 374 patients with asthma. Of the asthmatic patients, 100 performed exercise challenge tests before and after receiving montelukast (5 mg/day) for 8 weeks and included 80 subjects in drug responsiveness analysis. We assessed IL-13 polymorphisms (-1512A/C, -1112C/T, +2044G/A) through PCR-restriction fragment length polymorphism analysis. RESULTS: Significantly higher total IgE levels and maximum percent fall in forced expiratory volume in 1 s (FEV1) (%) after exercise challenge test were found in asthmatic patients carrying one or two copies of the IL-13 +2044A versus those homozygous for +2044G (P=0.011 and 0.040, respectively). We further noted a correlation of total IgE with maximum percent fall in FEV1 (%) in asthmatic patients, as well as a reverse correlation with improvement of maximum percent fall in FEV1 (%) after exercise challenge tests. Finally, we observed a significant association between responsiveness to montelukast and IL-13 -1112C/T polymorphism and the haplotype of IL-13 polymorphisms. CONCLUSION: The IL-13 +2044G/A polymorphism may be associated with atopy and EIB severity in Korean children with EIB, and thus could potentially be considered as a disease-modifying gene. Moreover, the IL-13 -1112C/T polymorphism and the haplotype of IL-13 polymorphisms seem to be associated with LTRA drug responsiveness, and thus might prove useful as a target for modulation of LTRA drug responsiveness.

Genetic factors in the presence, severity, and triggers of asthma.

The role of heredity in the presence of asthma, severity of the condition, and impact of 12 specific triggers of attacks was investigated. Health surveys containing questions about children's asthma characteristics were completed by 325 families with twin children across the United States. Data for 39 monozygotic twin pairs and 55 same sex dizygotic twin pairs who were between 2 and 20 years of age and had asthma present in at least one member of each pair were received and analysed. Results revealed higher concordance for the presence of asthma among monozygotic (58.97%; n = 23) than dizygotic twins (23.64%; n = 13). Further analyses were restricted to data from the concordant monozygotic and dizygotic twin pairs. Asthma severity (the product of attack frequency and intensity ratings) was significantly correlated for monozygotic pairs but not for dizygotic pairs, and this difference in monozygotic and dizygotic severity correlations was significant. Also, monozygotic twins showed significantly higher correlations than dizygotic twins for the impacts of two asthma triggers: respiratory infection and physical activity. These results indicate a role of heredity in the presence of asthma and suggest that genetic factors may also affect the severity of children's asthma condition and the impact of respiratory infection and physical exertion as asthma triggers.

Effect of exercise on pulmonary function tests in normal first degree relations of asthmatic subjects.

The prevalence of exercise-induced asthma (EIA) after six minutes of standard exercise test on bicycle ergometer was studied in thirty healthy first degree relations of asthmatic subjects (group II) and was compared with that in thirty healthy controls (group I). Pulmonary function tests (PFT) measuring FVC, FEV1, FEF25-75% and PEFR were performed on each subject prior of exercise, immediately following exercise period and serially at 5 minute interval for 25 minutes thereafter. Bronchial lability was noted in 7% and 27% of the subjects in groups I and II respectively. Of all the parameters measured, FEF25-75% exhibited most striking changes when expressed as % of the baseline value.