Corticosteroid-sparing options in the treatment of childhood asthma

Cysteinyl leukotriene receptor-1 antagonists as modulators of innate immune cell function

Cysteinyl leukotrienes (cysLTs) are produced predominantly by cells of the innate immune system, especially basophils, eosinophils, mast cells, and monocytes/macrophages. Notwithstanding potent bronchoconstrictor activity, cysLTs are also proinflammatory consequent to their autocrine and paracrine interactions with G-protein-coupled receptors expressed not only on the aforementioned cell types, but also on Th2 lymphocytes, as well as structural cells, and to a lesser extent neutrophils and CD8⁺ cells. Recognition of the involvement of cysLTs in the immunopathogenesis of various types of acute and chronic inflammatory disorders, especially bronchial asthma, prompted the development of selective cysLT receptor-1 (cysLTR1) antagonists, specifically montelukast, pranlukast, and zafirlukast. More recently these agents have also been reported to possess secondary anti-inflammatory activities, distinct from cysLTR1 antagonism, which appear to be particularly effective in targeting neutrophils and monocytes/macrophages. Underlying mechanisms include interference with cyclic nucleotide phosphodiesterases, 5′-lipoxygenase, and the proinflammatory transcription factor, nuclear factor kappa B. These and other secondary anti-inflammatory mechanisms of the commonly used cysLTR1 antagonists are the major focus of the current review, which also includes a comparison of the anti-inflammatory effects of montelukast, pranlukast, and zafirlukast on human neutrophils in vitro, as well as an overview of both the current clinical applications of these agents and potential future applications based on preclinical and early clinical studies.

Effects of curcumin on lung histopathology and fungal burden in a mouse model of chronic asthma and oropharyngeal candidiasis

BACKGROUND AND AIMS

Oropharyngeal candidiasis (OPC) is one of the most common local side effects of current therapy in chronic asthma. New therapeutic options with fewer side effects and reverse chronic changes are needed. Curcumin, as a promising antiinflammatory and antifungal agent, could be a candidate of alternative therapy in asthma. This study aimed to determine the efficacy of orally administrated curcumin on lung histopathology, serum nitric oxide levels and fungal burden in a murine model of asthma and OPC.

METHODS

Thirty five BALB/c mice were divided into five groups: I, II, III, IV (placebo) and V (control). All groups except the control were sensitized and challenged with ovalbumin. OPC model was established after the model of chronic asthma. Lung histology, serum nitric oxide levels and fungal burden were evaluated after 5 days of treatment with curcumin, dexamethasone, curcumin-dexamethasone combination and placebo. Evaluation of lung histology included subepithelial smooth muscle and epithelial thickness and number of goblet and mast cells by using light microscopy.

RESULTS

All histological parameters improved in curcumin group similar to dexamethasone group. Curcumin and dexamethasone-curcumin combination were also as effective as dexamethasone on decreasing nitric oxide levels. Oral fungal burden was significantly lower in curcumin-treated group than dexamethasone.

CONCLUSIONS

In our study we demonstrated that curcumin administration alleviates the pathological changes in asthma and decreases the fungal burden. Curcumin may have a potential effect on treating chronic asthma and decreasing the frequency of the OPC.

Effect of procaterol, a beta(2) selective adrenergic receptor agonist, on airway inflammation and hyperresponsiveness

BACKGROUND

beta-agonists are frequently used as bronchodilators for asthma as not only a reliever but also a controller, and their utility has increased with the development of long-acting beta(2) selective drugs. Although anti-inflammatory effects of beta(2) selective-agonists have been reported in vitro, side effects on augmentation of airway hyperresponsiveness by chronic use of beta(2) selective-agonists have been described in several reports. In this study, we investigated the effects of procaterol, a second-generation beta(2)-agonist, on airway inflammation in vivo using an antigen-specific murine model of asthma.

METHODS

Mice immunized with ovalbumin (OVA) + alum and challenged with inhaled ovalbumin were orally administered procaterol during the challenge. After inhalation, the mice were tracheostomized and placed in a body box under controlled ventilation to measure airway resistance before and after acetylcholine inhalation.

RESULTS

Administration of procaterol at a clinical dose equivalent did not augment airway hyperresponsiveness, inflammation of the airway wall, or subsequent airway wall thickening induced by OVA inhalation. BALF cell analysis revealed that the eosinophil number in the BALF was significantly reduced in procaterol-treated mice compared to untreated mice.

CONCLUSIONS

Oral administration of procaterol at a clinical dose did not augment airway responsiveness, but did reduce eosinophil inflammation.

A randomized open-label comparative study of montelukast versus theophylline added to inhaled corticosteroid in asthmatic children

BACKGROUND

Inhaled corticosteroids (ICSs) are widely used in combination with other classes of drugs for treatment of childhood asthma. The efficacy and the safety of montelukast added to low-dose ICS therapy were compared with those of sustained-release theophylline added to low-dose ICS therapy in asthmatic children in the present study.

METHODS

Following the 2-week run-in period, 6-to 14-year old patients receiving treatment with ICSs were randomized to treatment for 4 weeks with either montelukast 5 mg once daily or sustained release theophylline 5-8 mg/kg (dry syrup) or 100-200 mg (tablet) twice daily. Patients also received a fixed dose of ICS throughout the run-in and treatment periods. The primary efficacy endpoint was the change from baseline in peak expiratory flow (PEF) at Week 2.

RESULTS

A significant increase in morning PEF was observed in the add-on montelukast group as compared with the add-on theophylline group at Week 2 (change from baseline of 22.8 L/minvs. 8.7 L/min; p = 0.041 for between-group difference) and at Week 4 (31.0 L/minvs. 9.8 L/min; p = 0.012). A significant increase in evening PEF was observed in the add-on montelukast group as compared with the add-on theophylline group at Week 4 (24.7 L/minvs. 8.7 L/min; p = 0.027). There were no significant differences between the treatment groups in incidences of clinical and laboratory adverse experiences.

CONCLUSIONS

The results indicate that montelukast added to low-dose ICS is an effective and safe option for the treatment of asthma in children.

The chinese herbal medicine formula MSSM-002 suppresses allergic airway hyperreactivity and modulates TH1/TH2 responses in a murine model of allergic asthma

BACKGROUND

Asthma is a major public health problem worldwide, and the morbidity and mortality of asthma have increased in the past two decades. The reputed efficacy, low cost, and relative absence of side effects of traditional Chinese medicines (TCMs) have led to increasing interest in the use of TCMs for the treatment of asthma in Western countries. However, there are few well-controlled scientific studies on the efficacy, safety, and mechanisms of action of TCMs used to treat asthma.

OBJECTIVE

The goal of this study was to investigate the effects of the Chinese herbal medicine formula MSSM-002, derived from TCMs used to treat allergic asthma, on a well-characterized mouse model of allergic asthma.

METHODS

Mice sensitized intraperitoneally and challenged intratracheally with conalbumin were treated with MSSM-002 24 hours after the first intratracheal challenge. Dexamethasone-treated, saline solution sham-treated, and naive mice served as controls. The effects of MSSM-002 on allergic airway hyperreactivity, inflammation, antigen-specific antibody production, lung histologic features, and cytokine profiles were evaluated.

RESULTS

MSSM-002 treatment virtually eliminated airway hyperreactivity and markedly reduced the total number of cells and the percent eosinophils in bronchoalveolar lavage fluids compared with the sham-treated group. Lung histologic features showed that MSSM-002 reduced inflammation and mucus production. These effects were equivalent to the effects of dexamethasone, but in contrast to the overall immunosuppressive effects of dexamethasone MSSM-002 treatment decreased antigen-specific IgE, IL-4, IL-5, and IL-13 levels without suppressing IgG2a and IFN-gamma synthesis.

CONCLUSION

MSSM-002 exhibits anti-airway hyperresponsiveness, anti-airway inflammation, and immunoregulatory effects on T(H)1/T(H)2 responses, which may be useful for treatment of allergic asthma.