Comparative role of peptide leukotrienes and histamine in the development of nasal mucosal swelling in nasal allergy

Montelukast Effectively Treats the Nighttime Impact of Seasonal Allergic Rhinitis

Background

Nighttime problems constitute a significant burden on the quality of life of patients with seasonal allergic rhinitis (SAR). The aim of this study was to evaluate the effectiveness of montelukast on nighttime AR symptoms.

Methods

In seven multicenter, double-blind, parallel-group trials, nighttime problems were assessed as the nighttime symptoms score (NSS), an average of three individual symptom scores: difficulty going to sleep, nighttime awakening, and nasal congestion on awakening (each rated 0 = none to 3 = severe). Patients (aged 15–82 years) were randomized to receive montelukast, 10 mg (n = 1751), placebo (n = 1557), or the positive control loratadine, 10 mg (n = 1616).

Results

In a combined analysis, changes from baseline (mean ± SE) in NSS were -0.28 ± 0.01, -0.16 ± 0.01, and —0.24 ± 0.01 for the montelukast, placebo, and loratadine groups, respectively. Difference versus placebo in least-squares mean change from baseline were —0.11 (95% confidence interval, -0.14, -0.08; p ≤ 0.001) for montelukast and -0.09 (-0.12, -0.06; p ≤ 0.001) for loratadine. Strong baseline correlations (R > 0.70; p < 0.001) of NSS and two of its individual symptoms with the sleep domain of the validated Rhinoconjunctivitis Quality of Life Questionnaire support the validity and importance of measuring nighttime morbidity in SAR. Furthermore, a clinically important benefit of montelukast on the nighttime impact of SAR was shown using an analysis anchored on the Patient's Global Evaluation.

Conclusion

These data underscore the importance of nighttime problems in patients with SAR and the need to treat nighttime symptoms. In these studies, montelukast significantly improved the NSS, a clinically relevant and valid measure in patients with SAR.

Effects of leukotriene D4 and histamine nasal challenge on airway responsiveness and inflammation in persistent allergic rhinitis patients

BACKGROUND

Both histamine and leukotrienes are implicated in the pathogenesis of allergic rhinitis (AR), although the pattern and severity of the nasal response to these two potent inflammatory mediators may differ, which has not been adequately studied in patients with persistent AR.

OBJECTIVE

We sought to compare the differential effects of nasal challenge with leukotriene D₄ (LTD₄ ) and histamine on the airway response and inflammation in patients with AR.

METHODS

An open-label, crossover study was performed in 25 persistent AR patients (AR group) and 16 healthy subjects (control group). Participants randomly underwent histamine and LTD₄ nasal provocation within a two-week interval. Nasal symptoms according to a visual analogue scale (VAS), fractional exhaled nitric oxide (FENO), nasal lavage, induced sputum, and spirometry were evaluated before and after nasal challenge.

RESULTS

Nasal airway resistance (NAR) increased significantly after both LTD₄ and histamine nasal challenge in AR patients (P < .05). The potency of LTD₄ was 142-fold higher than that of histamine in increasing NAR (P < .001). The nasal symptom score induced by histamine challenge was significantly higher than that triggered by LTD₄ (3.42 ± 0.83 vs. 1.16 ± 0.94, P < .05) in the AR group. LTD₄ and histamine nasal challenge led to a significant increase in neutrophils in the nasal lavage and induced sputum (P < .05) in AR patients. There were no significant differences in the changes of eosinophils before and after LTD4 and histamine nasal challenges in nasal lavage and induced sputum. No significant changes in NAR, the induced symptom score, or inflammatory cells in the nasal lavage and sputum were found in the control group.

CONCLUSIONS

LTD₄ and histamine nasal challenge caused different patterns and severities of nasal symptoms, which correlated with symptoms (TSS) that affect patient's daily life. LTD4 was far more potent than histamine at increasing the NAR, while histamine nasal challenge induced more sneezing and nasal discharge. These results may guide the prescription of anti-histamine or anti-leukotriene agents for treating different AR phenotypes.

Leukotriene D4 nasal provocation test: Rationale, methodology and diagnostic value

Cysteinyl leukotrienes (LT) play a vital role in the pathogenesis of allergic rhinitis (AR), but few studies have investigated the nasal mucosal physiological response to LTs in AR patients. The aim of the present study was to establish the methodology and investigate the diagnostic value and safety of a leukotriene D4 (LTD4) nasal provocation test. LTD4 nasal provocation tests were performed in 26 AR patients and 16 normal control subjects. Nasal airway responsiveness was assessed by calculating the concentration of LTD4 required to cause a 60% increase in nasal airway resistance (PC60NAR-LTD4), which was measured using rhinomanometry and a composite symptom score. Receiver operating characteristic (ROC) curve was applied to evaluate the diagnostic value of LTD4 nasal provocation test, and adverse events were recorded. The study protocol was registered with the U.S. National Institutes of Health (https://clinicaltrials.gov/ct2/show/NCT01963741). PC60NAR-LTD4 in AR was significantly lower compared with that of normal controls [8.36 (IQR, 10.00) vs. 17.00 (IQR, 0.00) µg/ml, P=0.005]. Composite symptom score was higher in AR as compared with normal controls (1.19±0.94 vs. 0.12±0.50, P<0.001). The symptom scores included sneezing (0.12±0.34 vs. 0.00±0.00, P=0.149), rhinorrhea (0.79±0.66 vs. 0.06±0.25, P<0.001) and chemosis or itching of the eyes (0.06±0.25 vs. 0.21±0.42, P=0.216). High diagnostic value was indicated by the ROC [AUC: 0.822, 95%CI (0.665, 0.961)]. No serious adverse events were observed. Thus, the present results indicate that AR patients exhibited nasal hyperactivity to LTD4, and the established procedure of LTD4 nasal provocation testing is effective and safe for use in the diagnosis of AR.

Inflammation and infections in asthma

INTRODUCTION

Asthma is driven by an inflammatory response against normally harmless environmental inorganic and organic compounds in the respiratory tract. Immune responses to airborne pathogens such as viruses and bacteria may reduce the allergic responses but are also known to trigger asthma attacks and eventually lead to severe disease condition.

OBJECTIVE

To investigate the role of respiratory pathogens concerning the induction or protection against acute or chronic asthma manifestations.

METHODS

We included 131 articles for the final review according to their relevance with the subject.

RESULTS

There is apparently contradictory interaction of respiratory germs in the airways of asthmatics which may be protective on one angle but deleterious on the other.

CONCLUSION

The relationship between inflammation and remodeling and the pathogenic role of viral and bacterial infection in the airways of asthmatic patients is still highly debatable and incompletely understood.

Effects of montelukast on quality of life in patients with persistent allergic rhinitis

OBJECTIVE

To determine the effects of montelukast monotherapy on health-related quality of life (HRQL) in patients with persistent allergic rhinitis.

STUDY DESIGN

The study was placebo-controlled, randomized, and double blinded.

SETTING

Tertiary university hospital.

SUBJECTS AND METHODS

There were 46 patients in the study group and 24 patients in the control group, all of whom had a diagnosis of persistent allergic rhinitis of at least two years. The patients were evaluated at two control visits after the diagnosis. The study group was given 10-mg montelukast oral tablets, while the control group was given a placebo, and these were taken daily for one month. For evaluation of HRQL in both groups, the Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) was used.

RESULTS

There was a larger decrease in the overall RQLQ score for the group using montelukast compared with the placebo group (P < 0.001). The difference between scores at baseline versus the end of the first month for all domains was statically significant in both the placebo group and study group (P < 0.001). The difference in change from baseline to the end of the first month (treatment difference) between the placebo group and the study group was statically significant, in favor of the study group, for sleep, practical problems, nasal problems, and activities that have been limited by nose or eye symptoms, and for overall score (P < 0.001, P < 0.001, P = 0.003, P < 0.001, and P < 0.001, respectively).

CONCLUSION

Montelukast is a drug that improves the disease-specific quality of life in patients being treated for persistent allergic rhinitis better than placebo.

Cysteinyl leukotriene receptor CysLT1 as a novel therapeutic target for allergic rhinitis treatment

BACKGROUND

Cysteinyl leukotrienes (cys-LTs) play an important role in allergic rhinitis because CysLT(1) receptor antagonists relieve the symptoms of allergic rhinitis.

OBJECTIVE

I overview the clinical pharmacology of CysLT(1) receptor antagonists and their potential role in patients with allergic rhinitis.

METHODS

I review the evidence regarding the release of cys-LTs and localization of CysLT(1) receptor on nasal mucosa, and evaluate the clinical efficacy of CysLT(1) receptor antagonist in allergic rhinitis.

RESULTS/CONCLUSION

Immunohistochemical studies show that in allergic rhinitis, the major target of CysLT(1) receptor antagonists are the vascular bed and infiltrated leukocytes such as mast cells, eosinophils and macrophages. CysLT(1) receptor antagonists provide a new opportunity for simultaneous management of allergic diseases of the upper and lower respiratory tract.

The role of antileukotriene drugs in management of rhinitis and rhinosinusitis

Antileukotriene drugs have been studied for more than 15 years. In this review we examine the role of leukotrienes in rhinitis and rhinosinusitis, and explore the clinical literature supporting the use of anti-leukotriene agents in these diseases. Although these medications clearly are efficacious in rhinitis, it is unclear where in the armamentarium they should be used. The evidence for use in sinusitis has not been well studied except in sinusitis-associated aspirin-exacerbated respiratory disease. In this circumstance there is information that allows use of antileukotriene agents to be considered efficacious. We provide our rationale for use and await future clinical studies to answer this important question.

The importance of rhinitis on sleep, daytime somnolence, productivity and fatigue

PURPOSE OF REVIEW

The goal of treatment of allergic rhinitis should include improvement of daytime and nighttime symptoms, sleep, and quality of life. Congestion from allergic rhinitis is associated with decreased learning and productivity at work and school and a reduced quality of life. The release of inflammatory mediators and activation of inflammatory cells results in nasal congestion, causing disrupted sleep and subsequent daytime somnolence.

RECENT FINDINGS

This review presents evidence that allergic rhinitis causes sleep disruption, and discusses the pathophysiology of this process. The medications used to treat allergic rhinitis and their ability to improve sleep in patients with allergic rhinitis are reviewed.

SUMMARY

Some allergic rhinitis medications can be sedating; therefore, it is important to treat allergic rhinitis with medications that improve symptoms while producing few adverse effects. Medications such as the second-generation antihistamines and anticholinergic drugs are well tolerated, but have little effect on congestion. Intranasal corticosteroids reduce congestion, improve sleep and sleep problems, and reduce daytime sleepiness, fatigue, and inflammation. Recently, montelukast, a leukotriene receptor antagonist, has been added to the therapies approved for allergic rhinitis. Montelukast significantly improves both daytime and nighttime symptoms.

Cysteinyl leukotrienes: multi-functional mediators in allergic rhinitis

Cysteinyl leukotrienes (CysLTs) are a family of inflammatory lipid mediators synthesized from arachidonic acid by a variety of cells, including mast cells, eosinophils, basophils, and macrophages. This article reviews the data for the role of CysLTs as multi-functional mediators in allergic rhinitis (AR). We review the evidence that: (1) CysLTs are released from inflammatory cells that participate in AR, (2) receptors for CysLTs are located in nasal tissue, (3) CysLTs are increased in patients with AR and are released following allergen exposure, (4) administration of CysLTs reproduces the symptoms of AR, (5) CysLTs play roles in the maturation, as well as tissue recruitment, of inflammatory cells, and (6) a complex inter-regulation between CysLTs and a variety of other inflammatory mediators exists.

Distribution of specific binding sites for cysteinyl leukotriene 1 receptor antagonist in human nasal mucosa

CONCLUSION

The high density of [3H]-pranlukast binding sites on the local leukocytes in human nasal mucosa suggests that CysLT1 receptor antagonists may directly modulate cellular function of the local leukocytes through binding to CysLT1 receptor on allergic nasal mucosa.

OBJECTIVES

The cysteinyl leukotrienes (CysLTs) are lipid mediators that have been implicated in the pathogenesis of allergic diseases. Pharmacological studies using CysLTs indicate that two classes of receptors named CysLT1 and CysLT2 receptor exist. The former is sensitive to the CysLT1 receptor antagonist currently used to treat asthma and allergic rhinitis. To confirm the binding sites of CysLT1 receptor antagonist in human nasal mucosa, the autoradiographic distribution of CysLT1 receptor was studied in human nasal inferior turbinates.

MATERIALS AND METHODS

Cryostat sections were incubated with [3H]-pranlukast for autoradiography. Nonspecific binding was determined by adding unlabelled pranlukast.

RESULTS

Autoradiograms indicated [3H]-pranlukast densely labeled on the interstitial cells. Blood vessels were sparsely labeled. There was no specific labeling in the submucosal glands or epithelium. These results support our previous report from in situ hybridization and immunohistochemistry of CysLT1 receptor.

The role of leukotrienes in allergic rhinitis

OBJECTIVE

To review the role of cysteinyl leukotrienes (cysLTs) in allergic rhinitis and the scientific rationale for therapy with leukotriene receptor antagonists (LTRAs).

DATA SOURCES

Relevant basic science and clinical articles were identified by a search of the PubMed database for articles published from 1984 to 2004 using the following keywords: allergic rhinitis; nose; immune response; allergen challenge; leukotrienes C, D, and E; cysteinyl leukotriene; cysteinyl leukotriene receptor; cytokine; leukocyte; montelukast; zafirlukast; and pranlukast.

STUDY SELECTION

The authors' expert opinion was used to select studies for inclusion in this review.

RESULTS

CysLTs are synthesized via 5-lipoxygenase metabolism of arachidonic acid by mast cells and basophils during the early-phase response to antigen and by eosinophils and macrophages during the late phase. The cysLT levels in nasal secretions are elevated after short-term allergen instillation and in allergy season in patients with allergic rhinitis. These lipid mediators act locally and systemically by interacting with receptors, particularly the cysLT1 receptor, on target cells. Evidence derived from topical application of cysLTs in the nose and from the effects of LTRAs indicates that cysLTs contribute to nasal mucous secretion, congestion, and inflammation. CysLTs promote allergic inflammation by enhancing immune responses and the production, adhesion, migration, and survival of inflammatory cells such as eosinophils. They also increase the generation of an array of other proinflammatory mediators, such as cytokines, which in turn increase the production of and receptors for cysLTs. Clinical trials have demonstrated that LTRAs have significant but modest efficacy as single agents but additive efficacy when used with other classes of agents.

CONCLUSIONS

CysLTs fulfill the criteria for relevant mediators of allergic rhinitis via their diverse effects on immune, inflammatory, and local structural components of disease. By blocking the cysLT1 receptor responsible for most of these effects, LTRAs represent a useful approach to treatment of this important and prevalent disorder.

Effects of fexofenadine hydrochloride in a guinea pig model of antigen-induced rhinitis

Allergic rhinitis is an inflammatory disease of the nasal mucosa, induced by histamine, leukotrienes, and other substances released from mast cells. Fexofenadine hydrochloride, the active metabolite of terfenadine, is a novel, nonsedating antiallergic drug having H1 receptor antagonistic activity. Fexofenadine is effective for the treatment of allergic rhinitis. However, its mechanism of action in attenuating nasal congestion has not yet been elucidated. Therefore, we first examined the effects of fexofenadine on a guinea pig model of antigen-induced rhinitis. We also evaluated the effects of mepyramine, zafirlukast and ramatroban in this model; these drugs are an H1 receptor antagonist, a selective leukotriene antagonist and a selective thromboxane antagonist, respectively. Rhinitis was induced by ovalbumin (OVA) instillation into the nasal cavity of animals that had been sensitized by two earlier OVA injections (s.c. and i.p.). The nasal airway resistance was measured for 45 min after the challenge. Fexofenadine hydrochloride (20 mg/kg) and terfenadine (20 mg/kg) administered orally 70 min prior to the challenge significantly inhibited (fexofenadine, p < 0.001, terfenadine, p < 0.05) the increase in nasal airway resistance. Ramatroban (30 mg/kg) administered orally 60 min prior to the challenge also significantly inhibited (p < 0.05) the increase in nasal airway resistance. In contrast, mepyramine (3 mg/kg i.v.) and zafirlukast (3 mg/kg p.o.) failed to reduce the increase in nasal airway resistance. These results suggest that thromboxane may be involved in the increase in the nasal airway resistance in this model. Accordingly, fexofenadine may reduce the increase in nasal airway resistance by inhibiting the release of chemical mediators, including thromboxane, that are involved in the increase in nasal airway resistance in this model.

Therapeutic modulation of allergic airways disease with leukotriene receptor antagonists

Although asthma is one of the most common chronic respiratory conditions, it often remains unrecognized and undertreated, while patients are often reluctant to comply with regular inhaled anti-inflammatory and bronchodilator therapy. Allergic rhinitis co-exists with asthma in as many as 40% of patients, and can be regarded as a continuum of the same inflammatory disease process. Corticosteroids are the 'gold standard' first-line treatment for both conditions, and have a significant impact upon underlying inflammation, symptoms and long-term outcome. Cysteinyl leukotrienes are potent airway inflammatory mediators, suggesting that treatment antagonizing their effects could play a role in disease management. In recent years, leukotriene receptor antagonists have provided a further therapeutic option in the management of allergic airways disease. These drugs are orally active, can be administered once daily, and provide a systemic approach to the management of patients with asthma and allergic rhinitis. We review the pharmacology of leukotriene receptor antagonists, their potential role in clinical practice in patients with allergic airways disease, and likely areas for further research.

Acquired nasal hyperresponsiveness aggravates antigen-induced rhinitis in the guinea pig

Whether a state of nasal hyperresponsiveness influences antigen-induced biphasic nasal blockage and sneezing were examined using a guinea pig model of allergic rhinitis. Sensitized animals were challenged with an antigen, Japanese cedar pollen, once every week. Before the 13th challenge, the animals were randomly divided into 2 groups, and then the 13th challenge was performed (Groups A-0 and B-0). The 14th challenge was done on day 2 (Group A-2) and on day 7 (Group B-7) after the 13th challenge, on which nasal hyperresponsiveness was present and absent, respectively. Biphasic nasal blockage and sneezing after the challenge in Group A-2 were more severe than those in Group A-0, while those of Group B-7 were almost the same as those of Group B-0. An anti-histaminic, mepyramine, inhibited sneezing but not the biphasic nasal blockage in Group B-7. A cysteinyl leukotriene (CysLT) antagonist, pranlukast, suppressed the late nasal blockage but not the early blockage and sneezing in Group B-7. In contrast, in Group A-2, mepyramine significantly attenuated not only sneezing but also the early nasal blockage. Pranlukast significantly inhibited both nasal blockage and sneezing in Group A-2. In conclusion, nasal hyperresponsiveness aggravated the antigen-induced nasal responses, to which histamine and CysLTs considerably contributed.

Influences of allergic rhinitis on sleep

BACKGROUND

Allergic rhinitis is classically characterized by sneezing, pruritus, rhinorrhea, and nasal congestion. These symptoms can lead to impaired nocturnal sleep, and this impairment results in daytime fatigue and somnolence, reducing both learning and work efficiency and decreasing quality of life.

STUDY DESIGN

In addition, the mediators of AR, including histamine, leukotrienes, cytokines, and prostaglandins, may play a role in sleep regulation and, thus, may be directly involved in this impairment independent of nasal obstruction. Recumbency and/or diurnal variation augments turbinate swelling, causing nasal blockage during nocturnal sleep. Medications directed toward reversal of nasal congestion often concomitantly work through suppression of inflammatory mediators and constitute the primary therapy for sleep disturbance associated with allergic rhinitis. Some pharmaceutical interventions that reduce nasal congestion have adverse effects on sleep. Decongestants effectively reduce nasal congestion but frequently produce stimulatory effects and even insomnia. Antihistamines reduce sneezing and pruritus, but are less effective in relieving congestion. Earlier, "first-generation" antihistamines are associated with significant sedation. They also have anticholinergic properties, which can cause dry mouth and make mouth breathing even more uncomfortable in the allergic individual with nasal obstruction. The absence of anticholinergic properties in second-generation, largely nonsedating antihistamines limits their efficacy in rhinorrhea. Azelastine, a topical antihistamine, significantly reduces rhinorrhea and congestion and improves subjective sleep quality, but is also associated with increased sedation. Intranasal corticosteroids and oral leukotriene receptor antagonists effectively reduce rhinorrhea, congestion, and inflammatory mediators.

CONCLUSIONS

The efficacy of these medications at improving subjective sleep quality has been established through multiple randomized, double-blind, placebo-controlled clinical trials.

The emerging role of leukotriene modifiers in allergic rhinitis

Leukotriene modifiers have been shown to be efficacious in the treatment of asthma. Because of this success, and the fact that leukotrienes can be recovered not only from bronchoalveolar lavage fluid but also nasal lavage fluid, some researchers have suggested that these medications may also be useful for treating allergic rhinitis. Because the upper and lower airways are linked physically, there has been an assumption that therapy for upper and lower airway disease should be similar. This critical appraisal examines available data both supporting and refuting the emerging role of leukotriene modifiers in the treatment of allergic rhinitis. Although many studies have shown an improvement in nasal symptoms when comparing a leukotriene modifier with placebo, few studies have conclusively shown that a leukotriene modifier is any more effective in treating allergic rhinitis than an antihistamine. Results from several reported studies suggest that the addition of a leukotriene antagonist to an antihistamine is no more efficacious than antihistamine alone. However, many of these studies were small and/or primarily designed to examine the asthmatic response, with nasal symptoms being a lesser endpoint. To better understand how, where, and when leukotriene modifiers should be used in the armamentarium of therapies for allergic rhinitis, larger clinical investigations designed specifically to study allergic rhinitis need to be undertaken. We conclude that currently, the data do not support widespread use of a leukotriene modifier with or without an antihistamine in place of an intranasal corticosteroid with or without an antihistamine in the treatment of allergic rhinitis.

Leukotriene receptor antagonists for allergic rhinitis: a systematic review and meta-analysis

PURPOSE

To compare the clinical efficacy of leukotriene receptor antagonists with that of placebo, antihistamines, and nasal corticosteroids in patients with allergic rhinitis or nasal polyposis.

METHODS

We performed a systematic review and meta-analysis of randomized controlled trials of the effectiveness of leukotriene receptor antagonists in patients with rhinitis. Composite daily rhinitis symptom scores (as a percentage of the maximum score) and rhinitis-specific quality of life (unit scores ranging from 0 to 6) were pooled after assessing heterogeneity among studies. The pooled estimates were expressed as weighted mean differences between treatments in a random-effects model. We considered a difference of 10% in nasal score and 0.6 units in quality-of-life score to be clinically relevant.

RESULTS

Of the 196 citations, 11 studies on seasonal allergic rhinitis were used in the analysis: eight evaluating leukotriene receptor antagonists alone or in combination with other treatments versus placebo or other treatments (n = 3924) and three evaluating leukotriene receptor antagonists plus an antihistamine (n = 80). Leukotriene receptor antagonists reduced mean daily rhinitis symptom scores (in absolute terms) 5% (95% confidence interval [CI]: 3% to 7%) more than did placebo. However, antihistamines improved the nasal symptoms score 2% (95% CI: 0% to 4%) more than did leukotriene receptor antagonists, and nasal corticosteroids improved the score 12% (95% CI: 5% to 18%) more than did leukotriene antagonists. Leukotriene receptor antagonists significantly improved rhinoconjunctivitis quality of life by 0.3 units (95% CI: 0.24 to 0.36 units) when compared with placebo. There were no randomized controlled trials evaluating the effect of leukotriene receptor antagonists on perennial allergic rhinitis or polyposis.

CONCLUSION

Leukotriene receptor antagonists are modestly better than placebo, as effective as antihistamines, but less effective than nasal corticosteroids in improving symptoms and quality of life in patients with seasonal allergic rhinitis.

Recent advances in the management of asthma using leukotriene modifiers

Asthma is a chronic inflammatory disease of the airways that affects approximately 100 million people worldwide. In order to reduce symptoms, improve pulmonary function, and decrease morbidity, current treatment guidelines emphasize the importance of controlling the underlying inflammation in patients with asthma. Leukotrienes are leukocyte-generated lipid mediators that promote airway inflammation. Recognition of the importance of leukotrienes in the pathogenesis of asthma has led to the development of leukotriene modifiers, the first new class of drugs for the treatment of asthma to become available in 25 years. Controlled clinical trials with the four currently used leukotriene modifiers (montelukast, zafirlukast, and zileuton in the US and pranlukast in Japan) have established their efficacy in improving pulmonary function, reducing symptoms, decreasing night-time awakenings, and decreasing the need for rescue medications. They exert anti-inflammatory effects that attenuate cellular infiltration and bronchial hyperresponsiveness and complement the anti-inflammatory properties of inhaled corticosteroids. In patients with moderate and severe asthma, they permit tapering of the corticosteroid dose. In patients with exercise-induced asthma, leukotriene modifiers limit the decline in and quicken the recovery of pulmonary functions without the tolerance issues seen with chronic long-acting beta(2)-adrenoceptor agonist use. In patients with aspirin (acetylsalicylic acid)-induced asthma, they improve pulmonary function and shift the dose response curve to the right, reducing the patient's response to aspirin. In patients with seasonal allergic rhinitis, with or without concomitant asthma, they improve nasal, eye, and throat symptoms as well as quality of life. Leukotriene modifiers are generally safe and well tolerated with adverse effect profiles similar to that of placebo. The one safety issue raised with leukotriene modifiers, Churg-Strauss Syndrome, appears to be the unmasking of an already present syndrome that is manifested when the leukotriene modifiers permit corticosteroid doses to be reduced. Although current treatment guidelines recommend their use in patients with mild persistent asthma, these guidelines were developed just as leukotriene modifiers were coming to the market, before much of the clinical efficacy data were published. Because asthma is a heterogeneous disease, the different asthma phenotypes respond differently to therapies; consequently asthma therapy needs to be individualized. Leukotriene modifiers increase the therapeutic options for patients with asthma and, based on recent data, it is expected that future guidelines will describe expanded uses for these agents in clinical circumstances where these drugs are effective.

Allergic rhinitis: systemic inflammation and implications for management

Allergic rhinitis triggers a systemic increase of inflammation. Within minutes of allergen exposure, immune cells release histamine, proteases, cysteinyl leukotrienes, prostaglandins, and cytokines. Some produce the early symptoms, while others augment the production, systemic circulation, and subsequent infiltration of the nasal mucosa with inflammatory cells that sustain the symptoms. Systemic circulation of inflammatory cells permits their infiltration into other tissues where chemoattractant and adhesion molecules already exist. Consequently, allergic rhinitis is linked to comorbid conditions: asthma, chronic hyperplastic eosinophilic sinusitis, nasal polyposis, and serous otitis media. Effective therapy should be directed at underlying inflammation and its systemic manifestations. It should improve the rhinitis and the comorbid conditions. Antihistamines relieve early symptoms by blocking basophil- and mast cell-generated histamine, but they do not significantly influence the pro-inflammatory loop. They are often little better than placebo. Oral corticosteroids provide the systemic anti-inflammatory efficacy, but their toxicity precludes such an approach. Intranasal corticosteroids effectively target the local inflammatory processes of rhinitis, reducing local inflammatory cells within the nares, but they do not directly access tissues involved in the comorbid conditions. Leukotriene modifiers have both systemic anti-inflammatory effects and an acceptable safety profile.

Leukotriene receptor antagonist pranlukast suppresses eosinophil infiltration and cytokine production in human nasal mucosa of perennial allergic rhinitis

The purpose of this study was to investigate the influence of pranlukast on eosinophilic inflammation and cytokine production in human nasal mucosa. Twelve patients were treated with pranlukast, and samples were obtained from the nasal mucosa of the inferior turbinate. With respect to cell infiltration, a significant decrease was observed in the percentage of inflammatory cells (secreted eosinophil cationic protein [EG2] and neutrophil elastase) after treatment. The levels of cytokines and chemical mediators (interleukin [IL]-4, IL-5, RANTES [regulated on activation, normal T cell expressed and secreted], cysteinyl leukotrienes, IL-1beta, tumor necrosis factor-alpha, and IL-8) assessed by enzyme-linked immunosorbent assay and enzyme immunoassay were significantly decreased. These results indicate that pranlukast decreased the levels of a majority of the cytokines in nasal mucosa, leading to improvement in subjective nasal symptoms. Furthermore, these results support the hypothesis that pranlukast exerts its therapeutic action primarily by blocking the leukotriene receptors on eosinophils.

Cost-effective pharmacotherapy for inhalant allergic rhinitis

The otolaryngologist is one of the decision leaders for patients who seek to learn more about their problems of respiratory allergy. Although these patients do not have a life-threatening illness, the reduction of quality of life and performance can significantly restrict their overall sense of well being. Patients with allergic rhinitis desire the relief of the bothersome problems without other side effects. Second-generation antihistamines were introduced to reduce the significant impairment brought on by the sedation of the first-generation products. Most physicians prescribe the intranasal corticosteroids as the prescription drug of first choice for most patients with chronic allergic rhinitis. Second-generation H1 receptor antagonists are better for the patient than the first-generation drugs because of the reduced side-effect profile and improved tolerance. Compliance factors certainly need to be addressed with medications that need more than once-daily dosing. Patients with only sporadic problems in season or on limited exposure are best treated with oral antihistamines, topical cromolyn, and short-term decongestant therapy.

The role of leukotrienes in nasal allergy

OBJECTIVE

This review focuses on the role of cysteinyl leukotrienes (cysLTs) in nasal allergy. The purpose was to provide knowledge of the role of cysLTs in the pathophysiology of nasal allergy and the role of antileukotrienes in the treatment of nasal allergies. Materials and methods We conducted a literature review.

RESULTS

The proinflammatory effects of cysLTs have been well described in asthma. Antileukotrienes have proved to be an effective anti-inflammatory treatment for asthma patients. Similar to pathogenesis of asthma, cysLTs exert potent inflammatory effects in the upper airways and play a role in the pathogenesis of allergic rhinitis and other nasal allergies.

CONCLUSION

Antileukotriene treatment appears to be beneficial in nasal allergies. Allergic rhinitis is a complex, IgE-mediated inflammatory disease of the upper airways. It is the most common allergic disease, occurring in 10% to 30% of adults and up to 30% of children. It may be perennial or seasonal. Sneezing, itching, watery rhinorrhea, and nasal obstruction are classic symptoms. It may impair cognition, school/work performance and productivity, behavior, mood, and quality of life. On physical examination, clear secretions, nasal congestion, pink-bluish nasal mucosa, the allergic salute, and allergic shiners may be detected. Allergic rhinitis is a common comorbid condition with asthma, sinusitis, otitis media, nasal polyposis, and respiratory infections.

Minimal persistent inflammation, an emerging concept in the nature and treatment of allergic rhinitis: the possible role of leukotrienes

OBJECTIVE

To review the emerging concept of minimal persistent inflammation in allergic rhinitis and its implications for therapy.

DATA SOURCES

Relevant clinical studies in the English language were reviewed.

STUDY SELECTION

Material was taken from academic/scholarly journals.

RESULTS

Accumulating evidence suggests that allergic rhinitis is a chronic inflammatory disease instead of a disease of acute symptoms. An approach to the therapy for allergic rhinitis should consider that even when symptoms are absent, a minimal level of persistent inflammation may persist. To prevent unexpected exacerbations, the treatment strategy may need to include managing subclinical persistent inflammation. Therapeutic options addressing the major inflammatory elements in allergic rhinitis, including eosinophils, the cysteinyl leukotrienes, and histamine, must be evaluated as management strategies that can achieve effective control. Traditional medications include intranasal corticosteroids, antihistamines, and immunotherapy. Recently, a leukotriene receptor antagonist has been approved for major rhinitis symptoms (congestion, rhinorrhea, sneezing, and pruritus), suggesting a new option for the treatment of allergic rhinitis.

CONCLUSIONS

Because of the possible presence of a minimal persistent inflammation during rhinitis patients' asymptomatic periods, it is important to consider a prophylactic approach to treating allergic rhinitis to prevent or reduce exacerbations during an acute increase in allergen. In light of the advances in the understanding of the pathogenesis of allergic rhinitis, agents must be considered based on their safety, efficacy, and ability to deal with underlying inflammation as well as symptom relief.

The role of leukotriene inhibitors in patients with paranasal sinus disease

Leukotrienes are inflammatory mediators that are known as the slow-reacting substance of anaphylaxis produced by a number of cell types including mast cells, eosinophils, basophils, macrophages, and monocytes. Synthesis of these mediators results from the cleavage of arachidonic acid in cell membranes, and they exert their biologic effects by binding and activating specific adaptors. This occurs in a series of events that lead to contraction of the human airway smooth muscle, chemotaxis, and increased vascular permeability. These effects have led to their important role in the diseases of asthma, allergic rhinitis, and possible paranasal sinusitis with the formation of nasal polyps. Because these agents lead to the production of symptoms in patients that are asthmatic, the use of leukotriene enzyme inhibitors, particularly montelukast, and zafirlukasts seem appropriate. These classes of drugs can block the binding of leukotrienes to CysLT(1) receptors. Zileuton is a 5-lipoxygenase inhibitor that prevents the formation of leukotrienes and can also result in the prevention of leukotriene activity. Demonstrated efficacy in these patients in a number of studies has also suggested their role in inhibiting nasal symptoms in asthmatic patients. In addition, it has been suggested by serendipitous observations that many of the aspirin-intolerant patients have nasal polyps and that treatment with the leukotriene inhibitors has resulted in improvement and resolution of the polyps. Therefore, these agents may also play a role in patients afflicted with chronic sinusitis with concomitant nasal polyposis. These papers are discussed in detail because this form of therapy may represent a novel way to treat patients with this malady in addition to or in lieu of surgical treatment and steroid therapy.

Montelukast for treating seasonal allergic rhinitis: a randomized, double-blind, placebo-controlled trial performed in the spring

BACKGROUND

Cysteinyl leukotrienes are important proinflammatory mediators believed to have a role in allergic rhinitis.

OBJECTIVE

This multicentre, randomized, double-blind, placebo- and active-controlled trial evaluated the effectiveness and tolerability of montelukast, a cysteinyl leukotriene receptor antagonist, for treating patients with seasonal allergic rhinitis.

METHODS

After a 3- to 5-day, single-blind placebo run-in period, 1302 male and female patients (aged 15-81 years) with active allergic rhinitis symptoms were randomly assigned to receive montelukast 10 mg (n = 348), loratadine 10 mg (n = 602), or placebo (n = 352) administered once daily at bedtime for 2 weeks during the spring allergy season.

RESULTS

Mean patient characteristics and symptom scores at baseline were similar for the three treatment groups. The primary end-point, daytime nasal symptoms score (mean of nasal congestion, rhinorrhea, nasal pruritus, and sneezing scores; 0-3 scale), improved from baseline during treatment by (least squares mean, 95% confidence interval) - 0.37 (- 0.43, - 0.31), - 0.47 (- 0.52, - 0.43), and - 0.24 (- 0.29, - 0.18) in the montelukast, loratadine, and placebo groups, respectively (P < or = 0.001 comparing each active treatment with placebo). Mean changes from baseline in all other diary-based scores, including night-time and eye symptom scores, were significantly greater for each active treatment than for placebo. The rhinoconjunctivitis quality of life overall score improved significantly with montelukast and with loratadine as compared with placebo. Montelukast and loratadine showed a safety profile comparable to that of placebo.

CONCLUSION

Montelukast is well tolerated and provides improvements in daytime and night-time symptoms, as well as quality of life parameters, for patients with seasonal allergic rhinitis.

Expression and localization of the cysteinyl leukotriene 1 receptor in human nasal mucosa

BACKGROUND

The cysteinyl leukotrienes (CysLT) are lipid mediators that have been implicated in the pathogenesis of allergic diseases. Pharmacological studies using CysLTs indicate that two classes of receptors, named CysLT1 and CysLT2 receptor, exist. The former is sensitive to the CysLT1 antagonist currently used to treat asthma and allergic rhinitis. Recently, the cDNA for human CysLT1 and CysLT2 receptor have been cloned, making it now possible to study the gene expression of CysLTs receptors.

OBJECTIVE

We have used reverse transcription and polymerase chain reaction (RT-PCR) to study the gene expression of CysLT1 and CysLT2 receptor and in situ hybridization to determine the distribution of CysLT1 receptor mRNA in human nasal mucosa. In addition, the distribution of the CysLT1 receptor protein was studied by immunohistochemistry.

METHODS

Human turbinates were obtained after turbinectomy from six patients with nasal obstruction refractory to medical therapy. Total RNA was isolated from human nasal mucosa and both CysLT1 and CysLT2 receptor mRNA was detected in these tissues by using RT-PCR. For in situ hybridization study of human nasal mucosa, we used biotin-labelled oligonucleotides probes encoding human CysLT1 receptor cDNA. To identify the cells expressing the CysLT1 receptor protein, double immunostaining was performed by using anti-CysLT1 receptor antibody and monoclonal antileucocyte antibodies.

RESULTS

RT-PCR analysis of total nasal RNA demonstrated the expression of both CysLT1 receptor and CysLT2 receptor mRNA. In situ hybridization indicated high levels of CysLT1 receptor hybridization in blood vessels and the interstitial cells, but a sparse signal in airway epithelium and submucosal glands. The immunohistochemical studies revealed that anti-CysLT1 receptor antibody labelled eosinophils, mast cells, macrophages, neutrophils and vascular endothelial cells in the nasal mucosa.

CONCLUSION

The results may have an important clinical implication and also promote further investigation of the regulation of CysLT1 receptor in health and disease.

Clinical evidence for antileukotriene therapy in the management of allergic rhinitis

OBJECTIVE

This article presents information summarizing the findings of several clinical trials that evaluated the efficacy and safety of leukotriene receptor antagonists in the treatment of allergic rhinitis. After reading this article, readers will have a greater understanding of these clinical findings and their implications for the management of allergic rhinitis.

DATA SOURCES

Relevant and appropriately controlled clinical trials were used. Only literature in the English language was reviewed.

STUDY SELECTION

Material was taken from academic/scholarly publications, published abstracts, and papers presented at a major congress.

RESULTS

Similar to their contribution to the pathogenesis of asthma, cysteinyl leukotrienes have been found to exert potent inflammatory effects in the upper airways and to play a role in the pathogenesis of allergic rhinitis. The guidelines for the diagnosis and treatment of allergic rhinitis emphasize the importance of treating the pathophysiologic pathways of the disease. Thus, the use of antileukotriene therapy is a rational therapeutic option for patients with allergic rhinitis. Findings from several randomized, placebo-controlled clinical trials confirm the efficacy of leukotriene receptor antagonists in reducing the symptoms of allergic rhinitis and improving quality of life. Clinical experience with these medications has also demonstrated their tolerability and safety.

CONCLUSIONS

Results from recently completed and ongoing clinical trials have expanded the body of evidence for the safety and efficacy of antileukotrienes in the treatment of allergic rhinitis.

Pharmacological, pharmacokinetic and clinical properties of olopatadine hydrochloride, a new antiallergic drug

Olopatadine hydrochloride (olopatadine, 11-[(Z)-3-(dimethylamino)propylidene]-6,11-dihydrodibenz[b,e]oxepin-2-acetic acid monohydrochloride) is a novel antiallergic/histamine H1-receptor antagonistic drug that was synthesized and evaluated in our laboratories. Oral administration of olopatadine at doses of 0.03 mg/kg or higher inhibited the symptoms of experimental allergic skin responses, rhinoconjunctivitis and bronchial asthma in sensitized guinea pigs and rats. Olopatadine is a selective histamine H1-receptor antagonist possessing inhibitory effects on the release of inflammatory lipid mediators such as leukotriene and thromboxane from human polymorphonuclear leukocytes and eosinophils. Olopatadine also inhibited the tachykininergic contraction in the guinea pig bronchi by prejunctional inhibition of peripheral sensory nerves. Olopatadine exerted no significant effects on action potential duration in isolated guinea pig ventricular myocytes, myocardium and human ether-a-go-go-related gene channel. Olopatadine was highly and rapidly absorbed in healthy human volunteers. The urinary excretion of olopatadine accounted for not less than 58% and the contribution of metabolism was considerably low in the clearance of olopatadine in humans. Olopatadine is one of the few renal clearance drugs in antiallergic drugs. Olopatadine was shown to be useful for the treatment of allergic rhinitis and chronic urticaria in double-blind clinical trials. Olopatadine was approved in Japan for the treatment of allergic rhinitis, chronic urticaria, eczema dermatitis, prurigo, pruritus cutaneous, psoriasis vulgaris and erythema exsudativum multiforme in December, 2000. Ophthalmic solution of olopatadine was also approved in the United States for the treatment of seasonal allergic conjunctivitis in December, 1996 (Appendix: also in the European Union, it was approved in February 2002).

A comparison of once daily fexofenadine versus the combination of montelukast plus loratadine on domiciliary nasal peak flow and symptoms in seasonal allergic rhinitis

BACKGROUND

The combination of montelukast (ML) and loratadine (LT) has previously been shown to be superior to either drug alone in managing seasonal allergic rhinitis (SAR), whilst fexofenadine (FEX) has been shown to be better than LT as monotherapy.

OBJECTIVES

We wished to compare ML + LT vs. FEX alone for effects on daily measurements (am/pm) of peak inspiratory flow (PIF) and symptoms.

METHODS

Thirty-seven patients with SAR (skin prick positive to grass pollen) were randomised into a single-blind, double-dummy placebo (PL)-controlled cross-over study during the grass pollen season, comparing 2 weeks of once daily treatment with (a) 120mg FEX or (b) 10mg ML + 10mg LT. There was a 7-10 day placebo run-in and washout prior to each randomised treatment. The average of am/pm PIF (the primary outcome variable) was analysed. Patients recorded their symptom scores (from 0 to 3) twice daily, for nasal blockage, discharge, itching and sneezing with; total eye symptoms, ocular cromoglycate use, and daily activity. The total nasal symptom score was calculated as a composite (out of 24).

RESULTS

There were no significant differences between baselines after the run-in and washout placebos for any variables. There were significant (P < 0.05, Bonferroni) improvements in all symptoms and PIF compared to pooled placebo with both treatments for all end-points, but no differences between the two treatment regimes (as means and within-treatment 95% confidence intervals): PIF: PL 102 (98-107), FEX 111 (107-116), ML+LT 113 (109-118); total nasal symptoms: PL 7.4 (6.7-2.0), FEX 5.0 (4.3-5.7), ML + LT 4.0 (3.3-4.7).

CONCLUSIONS

Once daily FEX as monotherapy was equally effective as the combination of once daily ML + LT in improving nasal peak flow and controlling symptoms in SAR. Further studies are indicated to assess whether ML confers additional benefits to FEX in SAR.

Leukotriene receptor antagonists in the treatment of allergic rhinitis

OBJECTIVE

To review the literature examining the clinical use of leukotriene receptor antagonists in the treatment of allergic rhinitis.

DATA SOURCES

Biomedical literature accessed through MEDLINE (1990-November 2000) and Current Contents (week 35 of 1999 to week 48 of 2000). Key terms included leukotriene antagonists, montelukast, zafirlukast, and rhinitis (allergic).

DATA SYNTHESIS

Preliminary evidence on the clinical use of either montelukast or zafirlukast as monotherapy is equivocal, with one study noting benefit and another noting lack of benefit in symptom amelioration. A third study suggests that these agents may have a role in further modifying allergic rhinitis symptoms when used in combination with standard treatments.

CONCLUSIONS

Future large-scale studies should assess the efficacy of these agents in the treatment of allergic rhinitis, in particular, to identify subsets of patients likely to derive the most benefit. Available data suggest it is reasonable and safe to add these agents to standard therapy if symptomatology remains unresolved.

Nasal mucosal headache presenting as orofacial pain: a review of the literature and a case report

Headaches are a significant component of many facial pain syndromes. These facial pain/headache syndromes often have various etiologies, including neurologic, vascular, musculoskeletal, or combinations of vascular/musculoskeletal origins. Referred rhinologic headache, however, can be overlooked as a cause of facial pain in the dental literature. We report a case of nasal mucosal headache that presented as facial pain and include a review of the literature.

Involvement of neuropeptides in the allergic nasal obstruction in guinea pigs

The purposes of the present study were i) to determine whether neuropeptides induce the nasal obstruction in guinea pigs, and ii) to examine the possible involvement of neuropeptides in allergic nasal obstruction. The decrease in nasal cavity volume was determined by acoustic rhinometry as an index of nasal obstruction. In non-sensitized guinea pigs, substance P (SP), neurokinin A (NKA) and calcitonin gene-related peptide (CGRP) caused the nasal obstruction 10 to 30 min after their intranasal application. LY303870 (1 mg/kg), a tachykinin NK1-receptor antagonist; SR48968 (1 mg/kg), a tackykinin NK2-receptor antagonist; and CGRP(8-37) (50 nmol/kg), a CGRP1-receptor antagonist, administered intravenously before the intranasal application of the neuropeptides, inhibited the responses induced by SP, NKA and CGRP, respectively. In the guinea pigs sensitized with dinitrophenyl-coupled Ascaris suum allergenic extract, the intranasal antigen challenge caused nasal obstruction. The response was biphasic and consisted of the early phase response (EPR) and the late phase response (LPR), which developed 30 min and 6 h, respectively, after the antigen challenge. Intravenous administration of LY303870 (1 mg/kg) before the antigen challenge inhibited the EPR, while those of SR48968 (1 mg/kg) and CGRP(8-37) (50 nmol/kg) inhibited the LPR. The present results suggest that neuropeptides are involved in the allergic nasal obstruction.

Markedly increased nasal blockage by intranasal leukotriene D4 in an experimental allergic rhinitis model: contribution of dilated mucosal blood vessels

We examined whether nasal hyperresponsiveness to leukotriene (LT) D4 is seen in our allergic rhinitis model, which showed sneezing and biphasic nasal blockage by repeated antigen inhalation challenge, and whether a dilatation of mucosal blood vessels contributes to this hyperresponsiveness. Nasal blockage [increase of specific airway resistance (sRaw)] was indexed as nasal (hyper)responsiveness. The sensitized-challenged guinea pig showed a remarkable dose-dependent increase in sRaw by intranasal instillation of LTD4 (10 microl/nostril) at 10(-10) to 10(-6) M 10 h and 2 days but not 7 days after the challenge. The increase in sRaw induced by LTD4 was largely blocked by pranlukast or naphazoline, and this was dose-dependently suppressed by N(omega)-nitro-L-arginine methyl ester. Sodium nitroprusside induced an elevation of sRaw in the sensitized-challenged animal in the hyperresponsiveness state, but the degree did not differ from that in the non-sensitized-non-challenged group. The amount of NO2- and NO3- in nasal cavity lavage fluid after LTD4 instillation in the sensitized-challenged animal in the hyperresponsiveness state was significantly greater than that before the instillation. These results demonstrate that the hyperresponsiveness to LTD4 acquired by repeated antigen challenge is mainly due to dilatation of nasal blood vessels, which can be related to hyperproduction of nitric oxide through cysteinyl LT1-receptor activation.

Nasal secretion in ragweed-sensitized dogs: effect of leukotriene synthesis inhibition

Allergic rhinitis is an inflammatory disease associated with local leukotriene release during periods of symptoms. Zileuton, a leukotriene synthesis inhibitor, is known to inhibit the release of leukotriene B4. Because we previously showed that leukotriene B4 is a potent mediator of neutrophil-dependent nasal secretion, we investigated whether Zileuton inhibited allergen-induced nasal secretion. Using a newly developed method for isolating and superfusing a nasal segment, we examined the effect of Zileuton on nasal secretion and neutrophil recruitment in ragweed-sensitized dogs. Instillation of ragweed into the nasal segment caused time-dependent increases in the volume of airway fluid and the recruitment of neutrophils. Zileuton prevented ragweed-induced neutrophil recruitment and nasal secretion. These results indicate that leukotrienes are important mediators of allergy-induced nasal secretion in dogs. Future clinical studies in allergic patients will determine whether there is a therapeutic role for leukotriene synthesis inhibitors in modulating neutrophil recruitment and hypersecretion in the nose.