Allergic asthma: influence of genetic and environmental factors

Interleukin-10 promoter polymorphisms and asthma risk: a meta-analysis

Several studies assessed the associations of interleukin-10 (IL-10) polymorphisms with asthma in different populations. However, the results were inconclusive. The aim of the present study was to further assess the associations by the method of meta-analysis. Pubmed, EMBASE, Wanfang Database, China National Knowledge Infrastructure (CNKI) and Weipu Database were searched. Data were extracted independently by two authors. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations. Seventeen potentially eligible articles were identified (4478 cases and 4803 controls). Significant associations between -1082A/G and -592A/C polymorphisms and asthma were observed. However, there was no significant association between -819T/C polymorphism and asthma risk. In addition, there were significant associations of the IL-10 haplotypes with asthma. In summary, this meta-analysis suggested that IL-10 promoter polymorphisms were associated with asthma risk.

Xiao-Qing-Long-Tang attenuates allergic airway inflammation and remodeling in repetitive Dermatogoides pteronyssinus challenged chronic asthmatic mice model

ETHNOPHARMACOLOGICAL RELEVANCE

Xiao-Qing-Long-Tang (XQLT) has been used for centuries in Asia to effectively treat patients with bronchial asthma.

AIM OF THE STUDY

We previously found that single and multiple doses of XQLT administered to sensitized mice before allergen challenge resulted in suppressed airway hyper-responsiveness and airway inflammation. In this study we aimed to investigate whether XQLT has the potential to attenuate the severity of asthma symptoms, and immunomodulatory mechanism of XQLT in a repetitive Dermatogoides pteronyssinus (D. pteronyssinus)-challenged chronic asthmatic mice model.

MATERIALS AND METHODS

BALB/c mice were intratracheally (i.t.) inoculated with five doses of D. pteronyssinus (50 μl, 1mg/ml) and orally administered of XQLT (1 g/kg) at 1-week intervals. At three days after the last challenge, mice were sacrificed to evaluate airway remodeling, inflammation, lung histological features, and the expression profiles of cytokines and various genes.

RESULTS

XQLT significantly reduced bronchial inflammatory cell infiltration and airway remodeling. It inhibited D. pteronyssinus-induced total IgE and D. pteronyssinus-specific IgG1 in serum, and changed the "T(H)2-bios" in BALF by inhibiting the activation of NF-κB. Collagen assay and Histopathology indicated that XQLT reduced airway remodeling in the lung. Simultaneously, the RT-PCR analysis showed that XQLT downregulated IL-10, IL-13, RANTES, Eotaxin, and MCP-1 mRNA expression in the lung. Moreover, EMSA and immunohistochemistry staining demonstrated that XQLT inhibited NF-κB expression in the nucleus of bronchial epithelial cells.

CONCLUSIONS

These results suggest that XQLT exhibits anti-airway inflammatory, anti-airway remodeling, and specific immunoregulatory effects in a chronic asthmatic mice model.

Inflammatory marker sTREM-1 reflects the clinical stage and respiratory tract obstruction in allergic asthma bronchiale patients and correlates with number of neutrophils

The knowledge that asthma is an inflammatory disorder has prompted us to investigate the plasma levels of a new inflammatory marker sTREM-1 that is released from the surfaces of activated neutrophils and monocytes. The plasma levels of sTREM-1 were analysed by a sandwich ELISA test in the cohort of 76 patients with allergic asthma bronchiale and 39 healthy controls. Our results revealed more than 3.5 times higher levels of sTREM-1 in AB patients (92.3 pg/mL ± 125.6) compared with healthy subjects (25.7 pg/mL ± 9.2; P = 0.0001). Higher levels of sTREM-1 were found also in patients with exacerbated AB (170.5 pg/mL ± 78.2) compared with nonexacerbated AB patients (59.1 ± 78.2; P < 0.0001), patients with respiratory tract obstruction (176.4 pg/mL ± 177.8), than those without obstruction (51.99 pg/mL ± 64.0; P < 0.0001) and patients with anti-IgE therapy (P < 0.0001). Levels of sTREM-1 correlated with number of leucocytes (P = 0.002), and absolute number of neutrophils (P = 0.001). Elevated plasma levels of sTREM-1 reflect the severity, state of exacerbation, presence of respiratory tract obstruction in AB patients and together with increased number of neutrophils point to the role of neutrophils in inflammation accompanying AB.

The -675 4G/5G polymorphism in plasminogen activator inhibitor-1 gene is associated with risk of asthma: a meta-analysis

Background

A number of studies assessed the association of −675 4G/5G polymorphism in the promoter region of plasminogen activator inhibitor (PAI)-1 gene with asthma in different populations. However, most studies reported inconclusive results. A meta-analysis was conducted to investigate the association between polymorphism in the PAI-1 gene and asthma susceptibility.

Methods

Databases including Pubmed, EMBASE, HuGE Literature Finder, Wanfang Database, China National Knowledge Infrastructure (CNKI) and Weipu Database were searched to find relevant studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of association in the dominant model, recessive model, codominant model, and additive model.

Results

Eight studies involving 1817 cases and 2327 controls were included. Overall, significant association between 4G/5G polymorphism and asthma susceptibility was observed for 4G4G+4G5G vs. 5G5G (OR = 1.56, 95% CI 1.12–2.18, P = 0.008), 4G/4G vs. 4G/5G+5G/5G (OR = 1.38, 95% CI 1.06–1.80, P = 0.02), 4G/4G vs. 5G/5G (OR = 1.80, 95% CI 1.17–2.76, P = 0.007), 4G/5G vs. 5G/5G (OR = 1.40, 95% CI 1.07–1.84, P = 0.02), and 4G vs. 5G (OR = 1.35, 95% CI 1.08–1.68, P = 0.008).

Conclusions

This meta-analysis suggested that the −675 4G/5G polymorphism of PAI-1 gene was a risk factor of asthma.

Contribution of stress to asthma worsening through mast cell activation

OBJECTIVE

To review the available evidence linking stress to asthma and to investigate whether mast cells contribute to the effect of stress through activation by corticotropin-releasing hormone (CRH).

DATA SOURCE

The PubMed database was searched for articles (1998-2011) using the keywords anxiety, asthma, exacerbation, inflammation, mast cells, socioeconomic status, stress, violence, and worsening.

STUDY SELECTION

Articles were selected based on their relevance to the topic, with emphasis on clinical or epidemiologic data linking stress to asthma and studies that offered possible explanations for how stress may affect asthma.

RESULTS

Many articles point to an association between stress (socioeconomic status, interpersonal conflicts, emotional distress, terrorism) and asthma exacerbations but without any distinct pathogenetic mechanism. A few articles have reported reduced circulating cortisol and/or sensitivity to corticosteroids. We propose that mast cells, known to be involved in the pathophysiology of asthma, can be activated by CRH, which is secreted under stress in the lungs, leading to selective release of proinflammatory mediators. This effect may be augmented by neuropeptides or cytokines. CRH also reduces T-regulatory cell production of interleukin 10, which in known to inhibit allergic mast cell activation.

CONCLUSION

More studies are required to investigate lung levels of CRH and selective mast cell mediators. Reducing stress and using CRH receptor antagonists and/or mast cell blockers may serve as possible new therapeutic approaches for asthma.