Effects of inhaled corticosteroids, leukotriene receptor antagonists, or both, plus long-acting beta2-agonists on asthma pathophysiology: a review of the evidence

Trends and prescription patterns of traditional Chinese medicine use among subjects with allergic diseases: A nationwide population-based study

Background

The alarmingly rising prevalence of allergic diseases has led to substantial healthcare and economic burdens worldwide. The integrated use of traditional Chinese medicines (TCM) and Western medicines has been common in treating subjects with allergic diseases in clinical practice in Taiwan. However, limited studies have been conducted to evaluate long-term trends and prescription patterns of TCM use among subjects with allergic diseases. Thus, we conducted a nationwide population-based study to characterize TCM use among subjects with allergic diseases.

Methods

A total of 241,858 subjects with diagnosed atopic dermatitis, asthma or allergic rhinitis in the period of 2003–2012 were identified from the National Health Insurance Research Database (NHIRD) in Taiwan and included in this study. We assessed trends and prescribed patterns related to TCM (both single herbs and herbal formulas) among the study subjects over the 10-year study period.

Results

The overall proportions of TCM use were 30.5%, 29.0% and 45.7% in subjects with atopic dermatitis, asthma and allergic rhinitis, respectively. We found increasing trends of TCM use among subjects having atopic dermatitis and asthma, with annual increase of 0.91% and 0.38%, respectively, over the 10-year study period while the proportion remained steadily high (from 46.6% in 2003 to 46.3% in 2012) among subjects having allergic rhinitis. Moreover, the number of hospitalization due to allergic diseases in TCM users was significantly smaller than that in non TCM users for all three allergic diseases.

Conclusion

A notable proportion (30%–50%) of subjects with allergic diseases in Taiwan has used TCM, with the highest proportion of TCM use found in subjects with allergic rhinitis, whereas increasing trends of TCM use are found among subjects with atopic dermatitis and asthma, respectively. Our results suggest that TCM use may help reduce the severe episodes of allergic diseases necessitating hospitalizations.

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.

Montelukast added to fluticasone propionate does not alter inflammation or outcomes

BACKGROUND

Airway inflammation is a key pathological feature of asthma which underlies its clinical presentation.

OBJECTIVES

To examine whether adding a leukotriene modifier to an inhaled corticosteroid produces further clinical and/or anti-inflammatory benefits in patients symptomatic on short-acting beta(2)-agonists.

METHODS

Patients uncontrolled on short-acting beta(2)-agonists were treated for 12 weeks with either fluticasone propionate (100mcg BD) or fluticasone propionate (100mcg BD) and montelukast (10mg QD) in a randomized, double-blind, parallel group study. Bronchoscopy with endobronchial biopsy and bronchoalveolar lavage (BAL) was performed before and after treatment to compare effects on airway inflammation.

RESULTS

Of 103 subjects enrolled, 89 subjects completed treatment and 82 subjects had matched pair biopsy samples. Submucosal eosinophil counts, the primary endpoint, and asthma control improved to similar extents after both treatments (p<or=0.008). Both treatments significantly reduced submucosal mast cell, CD3+, CD4+, CD8+ and CD25+ cell counts. Submucosal mast cell reduction was greater in the fluticasone propionate plus montelukast group. There were no differences between treatments in BAL markers of inflammation or thickness of sub-epithelial collagen.

CONCLUSIONS

Low-dose fluticasone propionate significantly improves clinical disease control and reduces airway inflammation in asthma patients uncontrolled with short-acting beta(2)-agonists without further improvement when montelukast is added to low-dose fluticasone propionate.

Benefits of low-dose inhaled fluticasone on airway response and inflammation in mild asthma

RATIONALE

Current guidelines suggest that asthma should be controlled with the lowest dose of maintenance medication required.

OBJECTIVES

To evaluate the effects of a low dose of inhaled corticosteroid compared to a placebo, on airway inflammation and responsiveness in patients with mild symptomatic asthma.

METHODS

In this randomized double-blind, placebo-controlled, parallel group study, we looked at the influence of inhaled fluticasone propionate 250 microg/day for 3 months followed by 100 microg/day for 9 months on airway inflammation and methacholine responsiveness in non-smoking subjects with mild allergic asthma. Subjects were evaluated at baseline and 3, 6, 9 and 12 months after treatments; a 2-week evaluation of respiratory symptoms and peak expiratory flow measurements was done before each visit.

RESULTS

Fifty-seven subjects completed the 3-month study period. Airway responsiveness, expressed as the PC20 methacholine, increased by 0.27 and 1.14 doubling concentrations, respectively, in placebo-treated (n=33) and in fluticasone-treated (n=24) asthmatic subjects (p=0.03). An additional improvement in PC20 up to 2.16 doubling concentrations was observed in the fluticasone-treated group during the 9-month lower-dose treatment (p=0.0004, end of low-dose period compared with placebo). Sputum eosinophil counts decreased after 3 months of fluticasone 250 microg/day compared with placebo (p<0.0001) and remained in the normal range during the 9-month lower-dose treatment. Respiratory symptoms and peak expiratory flows did not change significantly throughout the study in both groups.

CONCLUSION

In mild asthma, keeping a regular minimal dose of ICS after asthma control has been achieved, may lead to a further reduction in airway responsiveness and keep sputum eosinophil count within the normal range.

Tissue remodeling and angiogenesis in asthma: the role of the eosinophil

This review covers the role of eosinophils in asthma-associated tissue remodeling and angiogenesis focusing on angiogenesis which is a recently discovered feature of asthma. In addition, novel directions for eosinophil-targeted/angiogenesis-targeted pharmacological intervention are discussed as new approaches in the treatment of asthma.

Correlation between the prostaglandin D(2)/E(2) ratio in nasal polyps and the recalcitrant pathophysiology of chronic rhinosinusitis associated with bronchial asthma

BACKGROUND

The prevalence of patients with chronic rhinosinusitis (CRS) refractory to traditional therapy appears to be on the increase. In these cases, CRS tends to be associated with bronchial asthma (BA), especially, aspirin-intolerant asthma (AIA). On the other hand, arachidonic acid metabolites have been extensively investigated in the pathogenesis of BA. We sought to assess the role of prostaglandin D(2) (PGD(2)) and prostaglandin E(2) (PGE(2)) in the recalcitrant pathophysiology of CRS.

METHODS

Samples were prepared from the nasal polyps and mucosa of 40 patients undergoing endoscopic sinus surgery (ESS) at our hospital. The nasal polyp specimens obtained from the patients with CRS were divided into three groups, as follows: the CRS-AIA group, consisting of specimens obtained from patients with CRS complicated by AIA, the CRS-ATA group, consisting of specimens obtained from patients with CRS associated with aspirin-tolerant asthma (ATA), and the CRS-NA group, consisting of specimens obtained from CRS patients without BA. PGD(2) and PGE(2) were extracted from the specimens and quantified.

RESULTS

The concentrations of PGD(2) were significantly higher in the nasal polyps of the CRS-ATA group. The concentrations of PGE(2) were lowest in the nasal polyps of the CRS-AIA group. The PGD(2)/PGE(2) ratio was highest in the CRS-AIA group.

CONCLUSIONS

It has previously been reported that CRS complicated by AIA is most likely to be characterized by repeated remissions and relapses, and is thus the most intractable. We may therefore say that the PGD(2)/PGE(2) ratio reflects the intractable nature of CRS.

Cortisol suppression as a surrogate marker for inhaled corticosteroid-induced growth retardation in children

Exposure of inhaled corticosteroids (ICSs) in pediatrics results in adrenal suppression and growth inhibition. The objective of this study was to assess the relationship of ICS mediated growth retardation with cortisol suppression in asthmatic children. A meta-analysis approach was performed with 33 published articles. Growth velocity (GV) data were obtained from the literature for evaluation of growth. Cumulative cortisol suppression within 24h (CCS%) was calculated at steady state with a validated algorithm. Consolidated GV and CCS% data were employed for model development. A linear mixed effects model was developed to adequately describe the relationship between GV and CCS%. No impact of tested covariates was observed. Population estimate of the rate of change in GV was -0.06cm/year/CCS% (12.7%, coefficient of variation) for both stadiometry and knemometry methods. However, GV from stadiometry is expected to be approximately three fold higher than that from knemometry when cortisol suppression was not presented. The final model was evaluated with posterior predictive check and pattern check approaches. The results from this study elucidate CCS% as an excellent predictor of ICS mediated growth retardation in asthmatic children.

Tolerability profiles of leukotriene receptor antagonists and long-acting beta2-adrenoceptor agonists in combination with inhaled corticosteroids for treatment of asthma: a review

Inhaled corticosteroids, long-acting beta2-adrenoceptor agonists, and leukotriene receptor antagonists are widely used for treatment of asthma. Inhaled corticosteroids are recommended as first-line therapy, whereas long-acting beta2-adrenoceptor agonists and leukotriene receptor antagonists are indicated as add-on therapy in patients not adequately controlled with corticosteroids alone. A number of studies have investigated the efficacy of combinations of these drugs in asthma, but several issues concerning the safety of these treatments are highly debated. This review provides a critical appraisal of the tolerability profiles of long-acting beta2-agonists and leukotriene receptor antagonists used in combination with inhaled corticosteroids for the treatment of asthma.

Pharmacogenetics, drug-metabolizing enzymes, and clinical practice

The application of pharmacogenetics holds great promise for individualized therapy. However, it has little clinical reality at present, despite many claims. The main problem is that the evidence base supporting genetic testing before therapy is weak. The pharmacology of the drugs subject to inherited variability in metabolism is often complex. Few have simple or single pathways of elimination. Some have active metabolites or enantiomers with different activities and pathways of elimination. Drug dosing is likely to be influenced only if the aggregate molar activity of all active moieties at the site of action is predictably affected by genotype or phenotype. Variation in drug concentration must be significant enough to provide "signal" over and above normal variation, and there must be a genuine concentration-effect relationship. The therapeutic index of the drug will also influence test utility. After considering all of these factors, the benefits of prospective testing need to be weighed against the costs and against other endpoints of effect. It is not surprising that few drugs satisfy these requirements. Drugs (and enzymes) for which there is a reasonable evidence base supporting genotyping or phenotyping include suxamethonium/mivacurium (butyrylcholinesterase), and azathioprine/6-mercaptopurine (thiopurine methyltransferase). Drugs for which there is a potential case for prospective testing include warfarin (CYP2C9), perhexiline (CYP2D6), and perhaps the proton pump inhibitors (CYP2C19). No other drugs have an evidence base that is sufficient to justify prospective testing at present, although some warrant further evaluation. In this review we summarize the current evidence base for pharmacogenetics in relation to drug-metabolizing enzymes.

Efficacy and safety of roflumilast in the treatment of asthma

BACKGROUND

The central role of chronic inflammation of the airways in asthma pathogenesis is supported by the efficacy of corticosteroids in controlling clinical symptoms. However, the search continues for potentially safer anti-inflammatory alternatives. Roflumilast is an oral, once-daily phosphodiesterase type 4 inhibitor with anti-inflammatory activity in preclinical models of asthma and chronic obstructive pulmonary disease.

OBJECTIVE

To investigate the dose-ranging efficacy and safety of roflumilast in patients with mild-to-moderate asthma.

METHODS

Patients (N = 693) were randomized in a double-blind, parallel-group, phase 2/3 study. After a 1- to 3-week placebo run-in period, patients (mean forced expiratory volume in 1 second [FEV1], 73% of predicted) were randomized to receive 100, 250, or 500 microg of roflumilast once daily for 12 weeks. The primary end point was change from baseline in FEV1; secondary end points included change from baseline in morning and evening peak expiratory flow.

RESULTS

Roflumilast use significantly increased FEV1 (P < .001 vs baseline). Improvements from baseline in FEV1 at the last visit were 260, 320, and 400 mL for the 100-, 250-, and 500-microg dose groups, respectively. Roflumilast, 500 microg, was superior to roflumilast, 100 microg, by 140 mL in improving FEV1 (P = .002). There were also significant improvements from baseline in morning and evening peak expiratory flow in all the dose groups (P < or = .006). Roflumilast was well tolerated at all doses tested. Most adverse events were mild to moderate in intensity and transient.

CONCLUSION

These results support the emerging role of roflumilast, 500 microg/d, in the treatment of asthma.

Effects of corticosteroid-induced apoptosis on airway epithelial wound closure in vitro

Damage to the airway epithelium is common in asthma. Corticosteroids induce apoptosis in and suppress proliferation of airway epithelial cells in culture. Whether apoptosis contributes to impaired epithelial cell repair after injury is not known. We examined whether corticosteroids would impair epithelial cell migration in an in vitro model of wound closure. Wounds (approximately 0.5-1.3 mm2) were created in cultured 1HAEo- human airway epithelial cell monolayers, after which cells were treated with up to 10 microM dexamethasone or budesonide for 24 h. Cultured cells were pretreated for 24 or 48 h with dexamethasone to observe the effect of long-term exposure on wound closure. After 12 h, the remaining wound area in monolayers pretreated for 48 h with 10 microM dexamethasone was 43+/-18% vs. 10+/-8% for untreated control monolayers. The addition of either corticosteroid immediately after injury did not slow closure significantly. After 12 h the remaining wound area in monolayers treated with 10 microM budesonide was 39+/-4% vs. 43+/-3% for untreated control monolayers. The proportion of apoptotic epithelial cells as measured by terminal deoxynucleotidyltransferase-mediated dUTP biotin nick end labeling both at and away from the wound edge was higher in monolayers treated with budesonide compared with controls. However, wound closure in the apoptosis-resistant 1HAEo-.Bcl-2+ cell line was not different after dexamethasone treatment. We demonstrate that corticosteroid treatment before mechanical wounding impairs airway epithelial cell migration. The addition of corticosteroids after injury does not slow migration, despite their ability to induce apoptosis in these cells.

Pharmacokinetic/pharmacodynamic evaluation of inhalation drugs: application to targeted pulmonary delivery systems

Inhaled therapy with either glucocorticoids and/or beta(2)-adrenergic drugs remains the mainstay of asthma treatment. In the last few years, a number of new products have been introduced into the market with the goal of improving efficacy and safety. This review article summarises the pharmacokinetic and pharmacodynamic properties of inhaled drugs for topical delivery necessary to achieve this goal. Pharmacokinetic properties include a high pulmonary deposition, low oral bioavailability, optimised pulmonary residence time and a very high systemic clearance. Optimisation of pharmacodynamic properties, such as receptor selectivity, may also yield drugs with improved pulmonary selectivity. As existing drugs also provide high efficacy and safety profiles, future developments will represent only slight improvements and quantum leap improvements are unlikely to occur.

Therapeutic approach to vascular remodelling in asthma

Bronchial asthma can be characterized by some significant changes in airway blood vessels, which may contribute to airway remodelling. Despite the clinical and functional consequences of bronchial microvascular remodelling in asthma, up to now, little data have been published on the therapeutic approach to this phenomenon. Corticosteroids are the only anti-asthma drugs that act positively on the three aspects of bronchial vascular remodelling: angiogenesis, dilatation and permeability. Modest positive effects of treatments with beta2-agonists and leukotrienes receptor antagonists on bronchial microcirculatory changes have been reported. In the future, agents that specifically inhibit angiogenesis could represent a novel approach for positively acting on bronchial microvascular changes in chronic inflammatory airway diseases, such as chronic bronchitis and asthma.

Prostaglandin, leukotriene, and lipoxin balance in chronic rhinosinusitis with and without nasal polyposis

BACKGROUND

Upper airway diseases and especially the aspirin hypersensitivity syndrome have been linked to changes in the arachidonic acid cascade; however, the specificity of these changes and their relation to inflammatory reactions in these diseases still remain controversial.

OBJECTIVE

We aimed to study the tissue eicosanoid production in 3 subgroups of patients with chronic rhinosinusitis (CRS) and control subjects and to correlate it with the severity of inflammation and clinical manifestation of aspirin sensitivity.

METHODS

Samples were prepared from sinonasal tissue of patients with CRS with (CRS-NP group, n = 13) and without nasal polyposis (CRS group, n = 11), sinonasal tissue of patients with nasal polyposis and aspirin sensitivity (CRS-ASNP group, n = 13), and normal nasal mucosa from healthy subjects (NM group, n = 8). Real-time PCR was applied for mRNA quantification of COX-2, 5-lipoxygenase, leukotriene C 4 synthase, and 15-lipoxygenase. Enzyme immunoassays were used to measure IL-5, eosinophil cationic protein, and eicosanoid (leukotriene [LT] C 4 , LTD 4 , and LTE 4 ; lipoxin A 4 ; and prostaglandin E 2 [PGE 2 ]) concentrations.

RESULTS

COX-2 mRNA and PGE 2 concentrations were similar in the CRS and NM groups but significantly decreased in nasal polyp tissue, especially in the CRS-ASNP group. LTC 4 synthase, 5-lipoxygenase mRNA, LTC 4 , LTD 4 , and LTE 4 concentrations increased with disease severity among the patient groups. 15-Lipoxygenase and lipoxin A 4 concentrations were increased in all CRS groups compared with in the NM group but were significantly downregulated in the CRS-ASNP group when compared with the CRS-NP group. IL-5 and eosinophil cationic protein were increased in both groups of nasal polyp tissue compared with in the NM and CRS groups and correlated directly with LTC 4 , LTD 4 , and LTE 4 concentrations and inversely with PGE 2 concentrations.

CONCLUSION

Changes of tissue eicosanoid metabolism do occur in CRS, even in the absence of clinical aspirin sensitivity, and these changes appear to be related to the severity of eosinophilic inflammation.

Research upregulation of CD23 (FcepsilonRII) expression in human airway smooth muscle cells (huASMC) in response to IL-4, GM-CSF, and IL-4/GM-CSF

BACKGROUND

Airway smooth muscle cells play a key role in remodeling that contributes to airway hyperreactivity. Airway smooth muscle remodeling includes hypertrophy and hyperplasia. It has been previously shown that the expression of CD23 on ASMC in rabbits can be induced by the IgE component of the atopic serum. We examined if other components of atopic serum are capable of inducing CD23 expression independent of IgE.

METHODS

Serum starved huASMC were stimulated with either IL-4, GM-CSF, IL-13, IL-5, PGD2, LTD4, tryptase or a combination of IL-4, IL-5, IL-13 each with GM-CSF for a period of 24 h. CD23 expression was analyzed by flow cytometry, western blot, and indirect immunofluorescence.

RESULTS

The CD23 protein expression was upregulated in huASMC in response to IL-4, GM-CSF, and IL-4/GM-CSF. The percentage of cells with increased fluorescence intensity above the control was 25.1 +/- 4.2% (IL-4), 15.6 +/- 2.7% (GM-CSF) and 32.9 +/- 13.9% (IL-4/GMCSF combination)(n = 3). The protein content of IL-4/GMCSF stimulated cells was significantly elevated. Expression of CD23 in response to IL-4, GM-CSF, IL-4/GM-CSF was accompanied by changes in cell morphology including depolymerization of isoactin fibers, cell spreading, and membrane ruffling. Western blot revealed abundant expression of the IL-4Ralpha and a low level expression of IL-2Rgammac in huASMC. Stimulation with IL-4 resulted in the phosphorylation of STAT-6 and an increase in the expression of the IL-2Rgammac.

CONCLUSION

CD23 on huASMC is upregulated by IL-4, GM-CSF, and IL-4/GM-CSF. The expression of CD23 is accompanied by an increase in cell volume and an increase in protein content per cell, suggesting hypertrophy. Upregulation of CD23 by IL-4/GM-CSF results in phenotypic changes in huASMC that could play a role in cell migration or a change in the synthetic function of the cells. Upregulation of CD23 in huASMC by IL-4 and GM-CSF can contribute to changes in huASMC and may provide an avenue for new therapeutic options in asthma targeting ASMC.