Cysteinyl leukotriene antagonism inhibits bronchoconstriction in response to hypertonic saline inhalation in asthma

Clinical efficacy of montelukast sodium combination therapy for cough variant asthma in children: A meta-analysis

This meta-analysis aims to assess the clinical effectiveness of combination therapy with montelukast sodium for the treatment of cough variant asthma (CVA) in children, intending to provide clinical evidence and data to guide the selection of clinical therapy. A literature review was conducted using numerous databases, including China National Knowledge Infrastructure (CNKI), Wanfang database, Embase, PubMed, and Web of Science, from inception to December 2023. Trials meeting the criteria for the combined treatment of montelukast sodium for CVA in children were included. Stata 16.0 software was utilized for meta-analysis. The combined treatment group received montelukast sodium in addition to the control group, while the control group received budesonide, fluticasone propionate, salmeterol-fluticasone, or ketotifen alone. This investigation included 18 papers. All subjects were from the Chinese population. Compared to the control group, the combined treatment group demonstrated a higher effective rate (relative ratio [RR] = 1.23, 95% confidence interval [CI]: 1.18-1.29, p < .001), but no difference in the incidence of adverse reactions (RR = 0.65, 95% CI: 0.42-1.02, p = .060) after treatment. Moreover, the peak expiratory flow (PEF) (SMD = 1.69, 95% CI: 1.09-2.30, p < .001), forced vital capacity (FVC) (SMD = 1.67, 95% CI: 0.94-2.39, p < .001), forced expiratory volume in 1 s (FEV1) (SMD = 1.74, 95% CI: 1.09-2.40, p < .001), and FEV1/FVC (SMD = 1.84, 95% CI: 0.41-3.28, p = .012) were significantly higher in the combined treatment group than in the control group after treatment. Compared with the control group, the levels of tumor necrosis factor-α (SMD = -2.38, 95% CI: -3.22 to -1.55, p < .001), IL-4 (SMD = -2.65, 95% CI: -3.26 to -2.04, p < .001), and IgE (SMD = -2.98, 95% CI: -3.24 to -2.72, p < .001) were significantly lower in the combined treatment group after treatment. The combined use of montelukast sodium in the treatment of pediatric CVA in China is associated with a significant clinical effect, making it a reasonable therapeutic approach.

Cysteinyl-leukotrienes promote cutaneous Leishmaniasis control

Leishmaniasis is a neglected tropical parasitic disease with few approved medications. Cutaneous leishmaniasis (CL) is the most frequent form, responsible for 0.7 - 1.0 million new cases annually worldwide. Leukotrienes are lipid mediators of inflammation produced in response to cell damage or infection. They are subdivided into leukotriene B4 (LTB₄) and cysteinyl leukotrienes LTC4 and LTD4 (Cys-LTs), depending on the enzyme responsible for their production. Recently, we showed that LTB₄ could be a target for purinergic signaling controlling Leishmania amazonensis infection; however, the importance of Cys-LTs in the resolution of infection remained unknown. Mice infected with L. amazonensis are a model of CL infection and drug screening. We found that Cys-LTs control L. amazonensis infection in susceptible (BALB/c) and resistant (C57BL/6) mouse strains. In vitro, Cys-LTs significantly diminished the L. amazonensis infection index in peritoneal macrophages of BALB/c and C57BL/6 mice. In vivo, intralesional treatment with Cys-LTs reduced the lesion size and parasite loads in the infected footpads of C57BL/6 mice. The anti-leishmanial role of Cys-LTs depended on the purinergic P2X7 receptor, as infected cells lacking the receptor did not produce Cys-LTs in response to ATP. These findings suggest the therapeutic potential of LTB4 and Cys-LTs for CL treatment.

Effects of treatment with montelukast alone, budesonide/formoterol alone and a combination of both in cough variant asthma

Background

Whether cysteinyl-leukotriene receptor antagonists (LTRAs) have a similar antitussive effect to inhaled corticosteroids and long-acting β2-agonist (ICS/LABA), and that LTRA plus ICS/LABA is superior to LTRAs alone or ICS/LABA alone in treating cough variant asthma (CVA) remain unclear. This study aimed to investigate and compare the efficacy of montelukast alone, budesonide/formoterol alone and the combination of both in the treatment of CVA.

Methods

Ninety-nine CVA patients were assigned randomly in a 1:1:1 ratio to receive montelukast (M group: 10 mg, once daily), budesonide/formoterol (BF group: 160/4.5 μg, one puff, twice daily), or montelukast plus budesonide/formoterol (MBF group) for 8 weeks. The primary outcomes were changes in the cough visual analogue scale (VAS) score, daytime cough symptom score (CSS) and night-time CSS, and the secondary outcomes comprised changes in cough reflex sensitivity (CRS), the percentage of sputum eosinophils (sputum Eos%) and fractional exhaled nitric oxide (FeNO). CRS was presented with the lowest concentration of capsaicin that induced at least 5 coughs (C5). The repeated measure was used in data analysis.

Results

The median cough VAS score (median from 6.0 to 2.0 in the M group, 5.0 to 1.0 in the BF group and 6.0 to 1.0 in the MBF group, all p < 0.001), daytime CSS (all p < 0.01) and night-time CSS (all p < 0.001) decreased significantly in all three groups after treatment for 8 weeks. Meanwhile, the LogC5 and sputum Eos% improved significantly in all three groups after 8 weeks treatment (all p < 0.05). No significant differences were found in the changes of the VAS score, daytime and night-time CSSs, LogC5 and sputum Eos% among the three groups from baseline to week 8 (all p > 0.05). The BF and MBF groups also showed significant decreases in FeNO after 8 weeks treatment (p = 0.001 and p = 0.008, respectively), while no significant change was found in the M group (p = 0.457). Treatment with MBF for 8 weeks significantly improved the FEV₁/FVC as well as the MMEF% pred and decreased the blood Eos% (all p < 0.05).

Conclusions

Montelukast alone, budesonide/formoterol alone and a combination of both were effective in improving cough symptom, decreasing cough reflex sensitivity and alleviating eosinophilic airway inflammation in patients with CVA, and the antitussive effect and anti-eosinophilic airway inflammation were similar.

Trial registration ClinicalTrials.gov, number NCT01404013.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02114-6.

Pharmacogenomics of Leukotriene Modifiers: A Systematic Review and Meta-Analysis

Pharmacogenetics research on leukotriene modifiers (LTMs) for asthma has been developing rapidly, although pharmacogenetic testing for LTMs is not yet used in clinical practice. We performed a systematic review and meta-analysis on the impact of pharmacogenomics on LTMs response. Studies published until May 2022 were searched using PubMed, EMBASE, and Cochrane databases. Pharmacogenomics/genetics studies of patients with asthma using LTMs with or without other anti-asthmatic drugs were included. Statistical tests of the meta-analysis were performed with Review Manager (Revman, version 5.4, The Cochrane Collaboration, Copenhagen, Denmark) and R language and environment for statistical computing (version 4.1.0 for Windows, R Core Team, Vienna, Austria) software. In total, 31 studies with 8084 participants were included in the systematic review and five studies were also used to perform the meta-analysis. Two included studies were genome-wide association studies (GWAS), which showed different results. Furthermore, none of the SNPs investigated in candidate gene studies were identified in GWAS. In candidate gene studies, the most widely studied SNPs were ALOX5 (tandem repeats of the Sp1-binding domain and rs2115819), LTC4S-444A/C (rs730012), and SLCO2B1 (rs12422149), with relatively inconsistent conclusions. LTC4S-444A/C polymorphism did not show a significant effect in our meta-analysis (AA vs. AC (or AC + CC): −0.06, 95%CI: −0.16 to 0.05, p = 0.31). AA homozygotes had smaller improvements in parameters pertaining to lung functions (−0.14, 95%CI: −0.23 to −0.05, p = 0.002) in a subgroup of patients with non-selective CysLT receptor antagonists and patients without inhaled corticosteroids (ICS) (−0.11, 95%CI: −0.14 to −0.08, p < 0.00001), but not in other subgroups. Variability exists in the pharmacogenomics of LTMs treatment response. Our meta-analysis and systematic review found that LTC4S-444A/C may influence the treatment response of patients taking non-selective CysLT receptor antagonists for asthma, and patients taking LTMs not in combination with ICS for asthma. Future studies are needed to validate the pharmacogenomic influence on LTMs response.

Zafirlukast promotes mitochondrial respiration by stimulating mitochondrial biogenesis in human bronchial epithelial cells

Lung diseases, including asthma, pose a serious global health issue. Loss of mitochondrial function and decreased mitochondrial biogenesis play pivotal roles in the initiation and progression of chronic lung diseases. Thus, maintaining mitochondrial function and homeostasis is an important treatment goal. Zafirlukast is a CysLTR1 antagonist that is widely used as an adjuvant treatment for asthma. In the present study, we investigated the effects of zafirlukast in vitro using human bronchial epithelial cells (BECs). We performed measurements of oxygen consumption and bioenergetics and found that zafirlukast increased mitochondrial respiration and biogenesis in human BECs as evidenced by increased mitochondrial mass and mtDNA/nDNA. Through real-time PCR and western blot analysis, we found that zafirlukast significantly increased the expression of PGC-1α, NRF1, and TFAM at both the mRNA and protein levels. Finally, we determined that these effects are mediated through CREB signaling and that inhibition of CREB with its specific inhibitor H89 abolished the effects of zafirlukast described above. Thus, zafirlukast might have potential in enhancing mitochondrial function by promoting mitochondrial biogenesis in human bronchial epithelial cells through upregulating the expression of PGC-1α and activating the CREB pathway.

Inflammatory markers as exacerbation risk factors after asthma therapy switch from inhaled steroids to montelukast

BACKGROUND

Asthma guidelines allow anti-leukotriene medications to be used as an alternative to inhaled corticosteroids (ICS) in second-step intensity therapy. The aim of the study was to analyze the risk factors of exacerbations, particularly inflammatory markers, during the 12-month period following therapy reduction from an ICS to montelukast in young patients with mild asthma.

METHODS

A total of 84 patients (aged 7-18 years old) with mild asthma controlled by low-dose ICS, had their treatment switched to montelukast. Exhaled nitric oxide (eNO), sputum eosinophils (sEos), and bronchial hyperreactivity (BHR) were assessed at the beginning and then every three months throughout the one-year period. The patients with asthma exacerbations (first severe or third mild) were discontinued from the study.

RESULTS

Over the study period, 22 patients (26%) discontinued montelukast due to asthma exacerbations. An increased risk of exacerbations was noted among patients with initial sEos above 2.5% (relative risk, RR 36.6; 95% CI: 7.1-189.3; p < 0.001), as well as those with augmented BHR (RR 9.5; 2.8-31.6; p < 0.001), or eNO greater than 20 ppb (RR 3.7; 95% CI: 1.3-10.7; p = 0.013). An increase in BHR and eNO was observed during the last visit before exclusion.

CONCLUSIONS

After switching treatment from a low-dose ICS, montelukast maintained control of asthma symptoms in 75% of patients. High sEos before the treatment change was the strongest exacerbation risk factor. In patients with asthma controlled by low-dose ICS and low inflammatory markers, treatment could be safely switched to montelukast.

Update on leukotriene, lipoxin and oxoeicosanoid receptors: IUPHAR Review 7

The endogenous ligands for the LT, lipoxin (LX) and oxoeicosanoid receptors are bioactive products produced by the action of the lipoxygenase family of enzymes. The LT receptors BLT1 and BLT2 , are activated by LTB4 and the CysLT1 and CysLT2 receptors are activated by the cysteinyl-LTs, whereas oxoeicosanoids exert their action through the OXE receptor. In contrast to these pro-inflammatory mediators, LXA4 transduces responses associated with the resolution of inflammation through the receptor FPR2/ALX (ALX/FPR2). The aim of the present review is to give a state of the field on these receptors, with focus on recent important findings. For example, BLT1 receptor signalling in cancer and the dual role of the BLT2 receptor in pro- and anti-inflammatory actions have added more complexity to lipid mediator signalling. Furthermore, a cross-talk between the CysLT and P2Y receptor systems has been described, and also the presence of novel receptors for cysteinyl-LTs, such as GPR17 and GPR99. Finally, lipoxygenase metabolites derived from ω-3 essential polyunsaturated acids, the resolvins, activate the receptors GPR32 and ChemR23. In conclusion, the receptors for the lipoxygenase products make up a sophisticated and tightly controlled system of endogenous pro- and anti-inflammatory signalling in physiology and pathology.

Evaluation of step-down therapy from an inhaled steroid to montelukast in childhood asthma

BACKGROUND

Asthma guidelines allow antileukotriene medications to be used as an alternative to inhaled corticosteroids (ICSs) in second-step intensity therapy. The aim of this study was to determine whether asthma control can be maintained after reducing treatment from low-dose ICS to montelukast.

METHODS

In this prospective, real-life 12-week trial, 84 young patients with asthma (7-18 years) controlled by low-dose ICS, had treatment switched to montelukast. Symptoms and PEF were monitored daily; exhaled nitric oxide (eNO) and spirometry every four weeks; sputum eosinophil (sEo) and bronchial hyperreactivity (BHR) assessed at the beginning and at the end of the study. The primary endpoint was number of patients discontinued from the study due to asthma exacerbations.

RESULTS

Eleven patients (13.1%) were discontinued due to asthma exacerbations. At the beginning, patients with elevated percentage of sEo had increased risk of exacerbations (relative risk RR, 6.6; 95% CI, 1.2-35.6), as well as those with augmented BHR (RR, 4.24; 95% CI, 1.1-16.2) as compared to patients who completed the study. An intensification of symptoms and increased use of beta-adrenergics were observed during the last visit before exclusion from the study, but not changes in spirometry, PEF, and eNO. No change in clinical parameters, inflammatory markers or BHR was observed in patients remaining in the study.

CONCLUSIONS

After treatment switch from low-dose ICS to montelukast, asthma control was maintained in the majority of patients during the 12-week observation period. Sputum eosinophilia or BHR before the treatment switch was exacerbation risk factor.