PURPOSE: Cysteinyl leukotrienes are important inflammatory mediators in the pathogenesis of asthma; therefore interruption of cysteinyl leukotrienes by leukotriene receptor antagonists improves clinical symptoms in the management of patients with mild to moderate asthma. We evaluated whether clinical response to montelukast, a leukotriene receptor antagonist, in childhood asthma was predicted by genotypes of leukotriene C4 synthase (LTC4S) promoter gene polymorphism. METHODS: An 8-week prospective, open trial of montelukast was carried out in 161 children with mild to moderate asthma. Genotyping of LTC4S gene polymorphism was determined by restriction fragment length polymorphism. RESULTS: The distribution of the LTC4S genotypes AA, AC, and CC was 70.8 percent, 23.6 percent, and 5.6 percent, respectively in asthma group and 74.0 percent, 22.6 percent, and 3.4 percent, respectively in control group. A statistically significant difference in the distribution of LTC4S genotype was not observed between the asthma and the control groups, and there was no significant difference between the LTC4S genotype and asthma severity. The responders to montelukast were significantly prevalent in the mild asthma group (P< 0.05). There was no significant difference in the distribution of the responders compared to non-responders within genotype in the total asthma group or the moderate asthma group. However, the responsiveness for montelukast was significant difference within genotype for both AA and AC/CC in the mild asthma group: The AA genotype was more included in the responder group (P< 0.05). CONCLUSION: In the mild persistent asthma group, the A allele of LTC4S polymorphism may be regarded as a predictable factor for clinical response to montelukast. However, LTC4S polymorphism was not significantly associated with the clinical response to montelukast in asthmatic children.
Alleles ; Asthma* ; Child ; Genotype ; Humans ; Leukotriene Antagonists ; Leukotriene C4* ; Leukotrienes ; Polymorphism, Restriction Fragment Length ; Prospective Studies ; Receptors, Leukotriene

OBJECTIVETo construct HEK293 cell lines stably expressing hCysLT(2) receptor, and to evaluate its application in screening of synthetic compounds with antagonist activity.

METHODSThe recombinant plasmid pcDNA3.1(+)-hCysLT(2) was transfected into HEK293 cells using Lipofectamin 2000. The transfected HEK293 cells were selected in 96 well plates by limiting dilution with 600 μg/ml C418 for 8 weeks. The expression of human CysLT(2) receptor was detected by RT-PCR and immunofluorescence staining. In HEK293 cells stably transfected with hCysLT(2), the agonist LTD(4)-induced elevation of intracellular calcium concentration ([Ca2(+)]i) was measured as the index for screening compounds with antagonist activity.

RESULTAfter selection in 96 well plates by limiting dilution, 12 monoclones were obtained and 11 of them highly expressed hCysLT(2) receptor. The positive control ATP at 50 μmol/L and LTD(4) at 100 nmol/L elevated [Ca2(+)]i in hCysLT(2)-HEK293 cells. AP-2100984 inhibited LTD(4)-induced [Ca2(+)]i elevation, but selective CysLT(1) receptor antagonists did not exert such an effect. The newly synthesized compounds DXW2, DXW3, DXW4, DXW5, DXW9, DXW25, DXW26, DXW29 and DXW35 at 1 μmol/L significantly inhibited LTD(4)-induced [Ca2(+)]i elevation. The IC(50) values of DXW4 and DXW5 were 0.25 μmol/L and 7.5 μmol/L.

CONCLUSIONHEK293 cell lines stably expressing hCysLT(2) receptor have been successfully constructed, and can be used to screen compounds with CysLT(2) receptor antagonist activity.

Drug Evaluation, Preclinical ; HEK293 Cells ; Humans ; Leukotriene Antagonists ; Receptors, Leukotriene ; genetics ; Transfection

PURPOSE: Cough-variant asthma (CVA) is a common cause of chronic cough in young children. Some children who have CVA eventually develop classic asthma. We evaluated the effect of inhaled corticosteroid and leukotriene receptor antagonist in young children who are suspected of having CVA. METHODS: Thirty-seven cough-variant asthma patients younger than 5-years-old were enrolled in this study. Fifteen were treated with pulmicort nebulization (500 micorgram, bid) for 4 weeks (Group A). Fourteen were treated with leukotriene receptor antagonist (Singulair, 4 mg) for 4 weeks (Group B). Eleven were treated with intermittent short-acting beta2-agonist nebulization (Group C). We evaluated the mean change of symptom score in night cough and sleep disturbance. RESULTS: There were no differences in age, sex, total IgE, total eosinophil count or duration of cough among the three groups. Group A and B showed significant improvement of night cough and sleep disturbance after treatment. (P< 0.05) In Group A and B, night cough was significantly improved after treatment more than in control. (P< 0.05) But improvements in sleep disturbance didn't have any signigicant differences between the three groups. (P= 1.0) CONCLUSION: Inhaled corticosteroid and leukotriene receptor antagonist are effective to control chronic cough in CVA children younger than 5-years-old.
Asthma* ; Budesonide ; Child ; Cough ; Eosinophils ; Humans ; Immunoglobulin E ; Receptors, Leukotriene*

OBJECTIVETo investigate whether cysteinyl leukotriene receptor 1 (CysLT₁ receptor) is involved in rotenone-induced injury of PC12 cells.

METHODSAfter 24 h treatment with rotenone or with rotenone and the CysLT₁ receptor antagonist montelukast, PC12 cell viability was determined by the colorimetric MTT reduction assay. After PC12 cells were treated with various concentrations of rotenone for 24 h or with 3 μmol/L rotenone for various durations, the expression of CysLT(1) receptor was determined by Western blotting, and its intracellular distribution was detected by immunocytochemistry.

RESULTSRotenone (0.3-30 μmol/L) induced PC12 cell injury; this injury was significantly attenuated by montelukast at 1 and 5 μmol/L.The expression of CysLT(1) receptor increased after rotenone treatment at 1-10 μmol/L, or at 3 μmol/L for 3 and 24 h. Rotenone caused concentration-and time-dependent translocation of CysLT₁ receptor from the nucleus to the cytosol.

CONCLUSIONCysteinyl leukotriene receptor 1 is involved in rotenone-induced injury of PC12 cells.

Animals ; PC12 Cells ; Rats ; Receptors, Leukotriene ; metabolism ; physiology ; Rotenone ; toxicity

Encephalitis ; metabolism ; pathology ; Microglia ; metabolism ; pathology ; Receptors, Leukotriene ; metabolism ; physiology

OBJECTIVETo establish a method for screening cysteinyl leukotriene receptor 2 (CysLT(2)) antagonists and to preliminarily screen a series of synthetic compounds.

METHODSRat glioma cell line (C6 cells) highly expressing CysLT(2) receptor was used. Intracellular calcium concentration was measured after stimulation with the agonist LTD(4),which was used to screen compounds with antagonist activity for CysLT(2) receptor. Bay u9773, a CysLT1/CysLT(2) receptor non-selective antagonist, and AP-100984, a CysLT(2) receptor antagonist, were used as control.

RESULTPT-PCR showed a higher expression of CysLT(2) receptor in C6 cells. LTD(4) at 1 mumol/L significantly increased intracellular calcium in C6 cells; the maximal effect was about 37.5% of ATP, a positive stimulus.LTD(4)-induced increase of intracellular calcium was blocked by CysLT(2) receptor antagonists, but not by CysLT(1) receptor antagonists. Among the synthetic compounds, D(XW-)1,2,13,23,29 and 30 inhibited LTD(4)-induced increase of intracellular calcium.

CONCLUSIONLTD(4)-induced change in intracellular calcium in C6 cells can be used as a screening method for CysLT(2) receptor antagonists. The compounds, D(XW-)1,2,13,23,29 and 30, possess antagonist activity for CysLT(2) receptor.

Animals ; Brain Neoplasms ; pathology ; Cell Line, Tumor ; Drug Evaluation, Preclinical ; methods ; Glioma ; pathology ; Leukotriene Antagonists ; isolation & purification ; Leukotriene D4 ; metabolism ; pharmacology ; Rats ; Receptors, Leukotriene ; chemistry

BACKGROUND AND OBJECTIVES: Mucin gene expression and mucin production are highly increased during inflammatory airway disorders such as, asthma, chronic bronchitis and sinusitis. Cytokines, lipopolysaccharides and other inflammatory mediators are related with secretion and production of mucin. However, among of inflammatory mediators, the relation of leukotrienes and mucin genes expression is not clear. The aim of this study is to evaluate MUC2/5AC genes expression and mucin secretion through leukotriene receptor in human airway epithelial cells. SUBJECTS AND METHOD: The effect of Leukotriene D4 and leukotriene receptor antagonist, pranlukast hydrate (ONO-1078) on the regulation of MUC2/5AC gene expression and mucin secretion was observed in the human airway NCI-H292 epithelial cells. The mRNA levels of MUC2/5AC and the amount of mucin protein were determined by reverse transcription-polymerase chain reaction (RT-PCR) and immunoassay. RESULTS: Leukotriene D4 upregulated MUC2/5AC gene expression and mucin secretion on a dose dependent pattern. Pranlukast hydrate (ONO-1078, 100 micrometer) downregulated the leukotriene D4-mediated MUC2/5AC gene expression and mucin secretion. CONCLUSION: These results suggest that the leukotriene receptor system is one of the expression mechanisms of MUC2/5AC genes and mucin secretion.
Asthma ; Bronchitis, Chronic ; Cytokines ; Epithelial Cells* ; Gene Expression ; Humans* ; Immunoassay ; Leukotriene Antagonists ; Leukotriene D4 ; Leukotrienes ; Lipopolysaccharides ; Mucins* ; Receptors, Leukotriene* ; RNA, Messenger ; Sinusitis

PURPOSE: Leukotriene receptor antagonists (LTRAs) are used to treat aspirin-intolerant asthma (AIA); however, the protective effects of long-term LTRA administration against aspirin-induced bronchospasm have not been evaluated. OBJECTIVES: We investigated the efficacy of a 12-week treatment with a LTRA in protecting against aspirin-induced asthma in AIA patients. METHODS: Fifty-two adult patients with AIA underwent an aspirin challenge test just before administration of montelukast (10 mg/day) and just after 12 weeks of treatment. The protective effect was assessed as the disappearance of aspirin-induced bronchospasm after 12 weeks of treatment. The results were compared according to the patients' clinical and physiological parameters. RESULTS: The decline in FEV1 following aspirin challenge was significantly reduced from 28.6+/-1.9% to 10.2+/-1.7% (P=0.0001) after 12 weeks of montelukast treatment. However, 14 subjects (30%) still showed a positive response (>15% decline in FEV1) to aspirin challenge. Grouping the subjects into good and poor responders according to post-treatment responses revealed that the pretreatment aspirin-induced FEV1 decline was significantly greater in the poor responders and that the triggering dose of aspirin and the induction time for a positive response were lower and shorter, respectively, in the poor responders. Histories of aspirin hypersensitivity and sinusitis were more prevalent among the poor responders than among the good responders. CONCLUSIONS: Twelve weeks of treatment with montelukast protected against aspirin-induced bronchospasm in 70% of the AIA cases. A poor response was associated with more severe aspirin-induced bronchospasms before treatment and a history of aspirin hypersensitivity or sinusitis. CLINICAL IMPLICATIONS: A severe response to aspirin challenge may be a predictor of poor responsiveness to leukotriene antagonist treatment.
Acetates ; Adult ; Aspirin ; Asthma ; Asthma, Aspirin-Induced ; Bronchial Spasm ; Eosinophils ; Humans ; Hypersensitivity ; Leukotriene Antagonists ; Quinolines ; Receptors, Leukotriene ; Sinusitis

Major classes of medication in asthma management include bronchodilating beta2-agonists, anti-inflammatory inhaled corticosteroids, leukotriene modifiers and theophyllines. However, all asthmatics do not respond to the same extent to a given medication. Available data suggest that a substantial range of individual variability, as much as 70%, may be due to genetic characteristics of each patient. Pharmacogenomics offers the potential to optimize medications for individual asthmatics by using genetic information to improve efficacy or avoid adverse effects. The best-studied case of the potential contribution of pharmacogenomics to treatment response in asthma comes from studies on human beta2 adrenergic receptors. In addition, genetic variation in beta2-adrenergic receptor (Arg16Gly) may predict response to anticholinergics for the treatment of asthma. In case of inhaled corticosteroids, a recent investigation using a traditional SNP-based approach identified a gene for corticotropin releasing hormone receptor 1 as a potential marker of response. Another major pathway that has been investigated is the pathway underlying response to cysteinyl leukotriene receptor antagonist. It is likely that in the near future, pharmacogenomic approaches based on individual genetic information will be introduced into an asthma treatment guideline and this guideline will allow us to identify those who have the best chance to respond to a specific medication.
Adrenal Cortex Hormones ; Asthma ; Cholinergic Antagonists ; Genes, vif ; Genetic Variation ; Humans ; Pharmacogenetics ; Receptors, Adrenergic ; Receptors, Corticotropin-Releasing Hormone ; Receptors, Leukotriene

PURPOSE: We evaluated the efficacy of leukotriene receptor antagonist and second generation anti-histamine in children with moderate to severe persistent allergic rhinitis. METHODS: Twenty eight patients who were treated with second generation anti-histamine for 4 weeks (Zyrtec syrup(R), Group A) and 58 patients who were treated with leukotriene receptor antagonist for 4 weeks (Singulair(R), Group B) were enrolled in this study. Control group (n=22) was received only first generation anti-histamine (Hydroxyzine) intermittently. Efficacy were evaluated by nasal scores in nasal congestion, rhinorrhea, nasal itching, sneezing and total nasal symptom score (a sum of patient ratings of nasal congestion, rhinorrhea, nasal itching, sneezing) before treatment and at 2 and 4 weeks after treatment. RESULTS: There were no difference in the total IgE and total eosinophil count of 3 groups. There were also no significant difference in the initial symptom scores. For nasal congestion, group A and B showed significant improvement at 2 and 4 weeks after treatment compared with controls (each P=0.006, P=0.000, P=0.023, P=0.001). For sneezing, group A and B showed significant improvement at 2 weeks after treatment compared with controls (each P=0.048, P=0.011) and group B also showed significant improvement at 4 weeks after treatment compared with controls (P=0.041). In total nasal symptom score (TNSS), group A and B showed significant improvement at 2 and 4 weeks after treatment compared with controls (each P=0.014, P=0.005, P=0.008, P=0.005). CONCLUSION: In the moderate to severe persistent allergic rhinitis, leukotriene receptor antagonist or second generation anti-histamine is effective in nasal congestion and sneezing.
Child ; Eosinophils ; Estrogens, Conjugated (USP) ; Humans ; Immunoglobulin E ; Pruritus ; Receptors, Leukotriene ; Rhinitis ; Rhinitis, Allergic, Perennial ; Sneezing