Inhibitory effect of levocabastine on allergen-induced increase of nasal reactivity to histamine and cell influx

The effect of levocabastine and furosemide pretreatment on hyperreactive response after nasal provocation with hypotonic aerosol in subjects with allergic rhinitis

Patients with allergic rhinitis demonstrate hyperreactive response in distilled water nasal provocation, shown by significant increase in nasal airway resistance (NAR). Antihistamines, including topical antihistamine, levocabastine, reduce response in non-specific nasal provocation tests. Furosemide is a diuretic which reduces hyperreactivity in lower airways, but the mode of its action is not yet fully understood. In this study, we hypothesized that either levocabastine or furosemide pre-treatment in allergic rhinitis patients reduced response to nasal challenge with non-isotonic aerosol. To test the hypothesis, we measured the effect of pre-treatment with levocabastine and furosemide in topical application on suppression of hyperreactive response to distilled water nasal inhalation. Nasal resistance was measured, prior to and after the provocation, by active anterior rhinomanometry in two randomized groups of patients, according to pre-treatment, either by levocabastine or furosemide, 20 patients in each group, respectively. Nasal airflow resistance and level of hyperreactive response considering nasal eosinophilia were tested. Significant increase in nasal resistance following provocation was found at baseline conditions (without pre-medication); pre-treatment with levocabastine and furosemide has suppressed such response. Patients with positive nasal eosinophilia showed a significantly higher increase in nasal resistance compared to those with negative smears. Furosemide has shown significantly better protective effect on nasal resistance increase in patients with positive eosinophils nasal smears. Levocabastine and furosemide pre-treatment suppress hyperreactive response to distilled water nasal provocation. Comparison of resistances (pre-treatment vs. without) showed more protective effect of furosemide, measured on both better and worse patent side of nose, in contrast to levocabastine group for which it was shown only on better patent side prior to provocation. Protection of furosemide was significantly more pronounced in patients with significant nasal eosinophilia.

Nedocromil sodium and levocabastine reduce the symptoms of conjunctival allergen challenge by different mechanisms

BACKGROUND

Nedocromil sodium and levocabastine are widely used for the treatment of ocular allergy, but their mechanisms of action are unclear.

OBJECTIVE

We sought to compare the efficacy and mechanisms of action of nedocromil sodium and levocabastine in reducing conjunctival symptoms after ocular allergen challenge.

METHODS

We performed a double-blind, placebo-controlled study in which 48 subjects were randomized to 3 groups to receive nedocromil sodium (2%), levocabastine (0.05%), or placebo eye drops twice daily for 2 weeks before ocular challenge with 10 microL of ryegrass extract. Symptoms and tear histamine and PGD(2) concentrations were determined before challenge and at 10, 20, 30, 60, 180, and 360 minutes after challenge. Bulbar biopsy specimens were taken at 6 and 24 hours after challenge to assess conjunctival inflammatory cell numbers, adhesion molecule expression, and mast cell-associated IL-4, IL-5, IL-6, IL-13, and TNF-alpha levels.

RESULTS

Both drugs significantly reduced total symptom scores (P <.05) at all times after challenge compared with placebo. Itching, hyperemia, and lacrimation were most affected. Nedocromil sodium treatment reduced tear concentrations of histamine (by 77%) and PGD(2) (by 70%) at 30 minutes after challenge (both P <.05). In biopsy specimens nedocromil sodium reduced the number of 3H4-positive mast cells (purportedly the secreted form of IL-4) by 49% at 6 hours and 59% at 24 hours (both P <.05). Levocabastine reduced intercellular adhesion molecule 1 expression by 52% at 6 hours and 45% at 24 hours (both P <.05).

CONCLUSION

Nedocromil sodium and levocabastine both reduced the conjunctival symptoms after ocular allergen challenge but appeared to work by different mechanisms. Nedocromil sodium reduced mast cell function, whereas levocabastine appeared to have primarily antihistaminic actions, although it also reduced the expression of intercellular adhesion molecule 1.

Comparison of the effects of fluticasone propionate, aqueous nasal spray and levocabastine on inflammatory cells in nasal lavage and clinical activity during the pollen season in seasonal rhinitics

BACKGROUND

Treatment options for allergic rhinitis include antihistamines, decongestants, anticholinergics, cromolyn sodium and corticosteroids. As the nose is a small organ, comprising less than 1% of total body mass and surface area, it seems logical to confine treatment of rhinitis to the diseased organ.

OBJECTIVE

To evaluate the effects of therapy with intranasal fluticasone propionate (FP), both on subjective symptoms and pathophysiological mechanisms, in rhinitis patients during pollen season when the patients were symptomatic.

METHODS

We used a double-blind, placebo (PLA)-controlled, randomized, double dummy, parallel group study of the effect of 6 weeks treatment. The double-blind comparison was made between the following three treatments: FP aqueous nasal spray, 200 microg taken once daily, levocabastine (LEV) nasal spray, 200 microg taken twice daily and PLA nasal spray. Clinical evaluation and the levels of cells and mediators in nasal washing were performed before and after treatments. Twenty-four patients (11 men and 13 women, aged 17-50 years, mean age 30.1 +/- 8.5) with strictly seasonal allergic rhinitis to Parietaria entered the study. Clinical evaluation and the levels of inflammatory cells (eosinophils and activated eosinophils, i.e. EG2+) and their mediators (tryptase, eosinophil cationic protein, eosinophil protein X and neutrophil myeloperoxidase) in nasal-lavage were performed before and after treatments.

RESULTS

Treatment with FP significantly increased, with respect to placebo, the percentage of days without sneezing (P < 0. 001), nasal blockage (P < 0.001), rhinorrhea (P < 0.001), nasal itching (P < 0.001). Furthermore, treatment with FP showed additional benefits with respect to LEV. The percentage of days without nasal blockage was significantly higher in the FP group that in the placebo group (P = 0.018). The same applied to rhinorrhea (P = 0.009). The percentages of days without sneezing and itching were instead not significantly different between the two groups. As expected, no significant differences were observed in baseline medians of the rhinitis symptom scores as well as in mean values of all mediators and eosinophils in nasal lavages of the various groups under study. After treatment the mean of subjective symptoms as well as all values in nasal lavage level fell significantly only in the FP group, whereas no significant changes were observed either in LEV or PLA groups. Accordingly, significant differences were observed at the end of the treatments between the values of fluticasone group vs LEV and PLA group values. Significant correlations between these values and symptom scores were found, according with literature data suggesting a pathogenetic role for these mediators and eosinophils in rhinitis.

CONCLUSION

FP (200 microg once daily) affords a significant degree of improvement in rhinitis control during pollen season, as measured by subjective and objective parameters, compared with LEV (200 microg twice daily) and PLA. The therapeutic benefits of intranasal FP are reflected in, and may be caused by, the decrease in nasal inflammatory cells.

Effects of topical budesonide and levocabastine on nasal symptoms and plasma exudation responses in seasonal allergic rhinitis

This study compares the effects of two topical nasal treatments for allergic rhinitis, budesonide and levocabastine, on symptom development during seasonal pollen exposure. Additionally, the protective effects of drug treatments on allergen-challenge-induced responses (symptoms and microvascular exudation of plasma) are examined late into the pollen season. Forty-four patients with seasonal allergic rhinitis to birch pollen participated in this single-blind, randomized, and placebo-controlled study. Topical nasal treatment with either levocabastine (200 microg b.i.d.; n = 16), budesonide (200 microg b.i.d.; n = 16), or placebo (n = 12) was instituted before the start of the pollen season and continued for 5 weeks until the end of the birch pollen season. The participants kept diaries for scores of nasal and ocular symptoms. Nasal allergen challenges with increasing doses of a birch pollen extract (10[2], 10[3], and 10[4] SQ-U) were carried out both before, when patients were asymptomatic and without treatment, and late into the pollen season. A nasal lavage followed each challenge, and the lavage fluid levels of albumin were measured as an index of the acute inflammatory response of the allergic mucosa. The birch pollen season was rather mild, producing only small increases in nasal symptoms. Budesonide treatment reduced the total nasal symptoms compared to placebo (P<0.01) and to levocabastine (P<0.05), while levocabastine treatment did not differ significantly from placebo. Ocular symptoms and use of rescue medication did not differ between placebo and the active treatments. At the end of the pollen season, both treatments reduced allergen-challenge-induced nasal symptoms compared to placebo (P<0.01). Only budesonide reduced allergen-challenge-induced increments of albumin levels in postchallenge nasal lavage fluids (P<0.05, in comparison with placebo). The results suggest that budesonide reduces both seasonal and allergen-challenge-induced nasal symptoms, while levocabastine is effective against allergen-challenge-induced symptoms also during the season. In addition, the topical steroid treatment, but not the antihistamine, inhibits the inflammatory exudation evoked by allergen challenge in patients with active seasonal disease.

Antihistamines: topical vs oral administration

The pathogenesis of allergic rhinitis is complex, involving not only histamine and mast cell-derived tryptase, but also eosinophil- and neutrophil-derived mediators, cytokines, and intercellular cell adhesion molecules (ICAM-1). It is surprising that antihistamines, which block only one component of the process, have proved so effective in the management of allergic rhinitis. Research has therefore focused on whether antihistamines have additional pharmacological activities. In vitro studies have shown that high concentrations of second generation antihistamines can block inflammatory mediator release from basophils and mast cells, and reduce ICAM-1 expression in epithelial cell lines. In vivo studies have also shown an effect on the allergen-induced inflammatory reaction; both oral and intranasal antihistamines cause a reduction in nasal symptoms and inflammatory cell influx. Oral terfenadine and cetirizine and intranasal levocabastine and azelastine have also demonstrated a lowering of ICAM-1 expression on epithelial cells. With regard to clinical efficacy, topical levocabastine (0.5 mg/mL eye drop solution and 0.5 mg/mL nasal spray) was shown to be more effective than oral terfenadine (60 mg twice daily) in relieving ocular itch (P = 0.02) and reducing nasal symptoms in allergic rhinoconjunctivitis. In a further study, levocabastine eye drops were as effective and well tolerated as sodium cromoglycate in seasonal allergic rhinitis. Intranasal azelastine (0.28 mg twice daily) showed a trend for superior relief of rhinorrhoea and nasal obstruction compared with oral terfenadine (60 mg twice daily). In addition, intranasal azelastine (0.28 mg twice daily) resulted in significant reductions in sneezing, nasal obstruction, rhinorrhoea and itching in perennial rhinitis, compared with the lower efficacy of beclomethasone dipropionate (0.1 mg twice daily). As well as benefits in efficacy, topical administration is associated with improved safety. Some antihistamines, particularly those metabolized in the liver, are associated with occasional reports of severe side-effects. It is therefore logical to administer antihistamines directly to the target organ.

Selective effect of levocabastine on histamine receptor and histamine release from human leukocytes and guinea pig isolated tissue

BACKGROUND

Levocabastine is a potent histamine H1 receptor antagonist used topically in the treatment of patients with allergic rhinitis. It has been suggested that antihistamines also have anti-inflammatory properties.

OBJECTIVE

The present study was performed to investigate whether levocabastine, in addition to the anti-H1 receptor activity, has anti-inflammatory properties and thus is able to modulate the release of histamine and cytokines, such as interleukin 5 from human leukocytes and isolated tissues.

METHODS

Leukocytes suspensions were prepared by dextran sedimentation of peripheral venous blood drawn from allergic and healthy volunteers. Leukocytes obtained from allergic volunteers were preincubated for 30 minutes with levocabastine (doses 10(-8) M to 10(-6) M) and thereafter incubated with allergen. Leukocytes obtained from healthy volunteers were incubated for zero to three hours with levocabastine (doses 10(-14) M to 10(-3) M). Histamine release was measured by an automated fluorometric method. Interleukin-5 release was measured by enzyme linked immunoassay. Contractile responses to histamine on guinea pig trachea and lung parenchyma as well as the release of histamine and interleukin-5 by the tissues were investigated in the absence or presence of levocabastine and/or the histamine H2 receptor antagonist cimetidine.

RESULTS

Levocabastine did not influence allergen-induced histamine release from leukocytes obtained from allergic volunteers. High concentrations (10(-4)and 10(-3) M) of levocabastine, however, caused release of histamine from leukocytes obtained from healthy volunteers as well as guinea pig airway smooth muscle tissues. Pretreatment with levocabastine dose-dependently decreased the contractile response to histamine, showing an irreversible competitive mechanism. Interleukin 5 release from human leukocytes and by guinea pig airway smooth muscle was not detectable.

CONCLUSIONS

These findings indicate that the H1 receptor blocker, levocabastine, has probably no anti-inflammatory properties, measured as histamine release, and that the histamine release from both human leukocytes and guinea pig trachea and lung parenchyma is significantly increased by the drug only at high concentrations.