Effect of oxymetazoline on the early response to nasal challenge with antigen

Effect of intranasal fluticasone furoate and intraocular olopatadine on nasal and ocular allergen-induced symptoms

BACKGROUND

Nasal allergen challenge (NAC) leads to a nasal ocular reflex, which is augmented by allergic inflammation. This study was designed to confirm our previous observation that an intranasal steroid inhibits the nasal ocular reflex and to show that histamine does not play an important role in the genesis of this reflex.

METHODS

We performed a randomized, double-blind, double-dummy, placebo (PL)-controlled, four-way crossover trial in subjects with seasonal allergic rhinitis out of season. Subjects were randomized to receive 1 week pretreatment with intranasal PL and intraocular (PL/PL), intranasal PL and intraocular olopatadine (PL/OLO), intranasal fluticasone furoate (FF) and intraocular PL (FF/PL), and the combination (FF/OLO). Subjects then underwent NAC on 2 consecutive days. The number of sneezes and nasal and ocular symptoms were recorded, and levels of tryptase and histamine were measured in nasal lavages.

RESULTS

NAC after PL/PL resulted in increase in symptoms, histamine, and tryptase after the challenge on the 2nd day. There was a reduction in eye symptoms on the 2nd day of challenge from 6.0 after PL/PL to 0 after FF/PL (p = 0.001), 2.5 after PL/OLO (p = 0.3), and 1.5 after FF/OLO (p = 0.003). Furthermore, there was no significant difference between the response after FF/PL versus FF/OLO and a significant difference between FF/PL and PL/OLO (p = 0.02). Levels of tryptase followed a similar trend. The number of eosinophils in nasal lavages on the 2nd day of challenge were also reduced by the treatment arms containing FF compared with PL.

CONCLUSION

Our data confirm the existence of a nasal ocular reflex after NAC. OLO alone or the addition of OLO to FF does not impact ocular symptoms caused by the naso-ocular reflex, suggesting that mast cells are not activated to release histamine in the conjunctiva during this process.

The effects of the nasal antihistamines olopatadine and azelastine in nasal allergen provocation

BACKGROUND

Olopatadine, an antihistamine used in allergic conjunctivitis, is under development as a nasal preparation for the treatment of allergic rhinitis.

OBJECTIVES

To evaluate the efficacy of olopatadine in suppressing symptoms and biomarkers of the immediate reaction induced by nasal allergen provocation and to compare olopatadine with azelastine in the same model.

METHODS

The study was approved by the Johns Hopkins University institutional review board, and all subjects gave written consent. We studied 20 asymptomatic subjects with seasonal allergic rhinitis. The study had 2 randomized, double-blind, placebo-controlled, crossover phases that evaluated 2 concentrations of olopatadine, 0.1% and 0.2%. In a third exploratory phase, olopatadine, 0.1%, was compared with topical azelastine, 0.1%, in a patient-masked design. Efficacy variables were the allergen-induced sneezes, other clinical symptoms, and the levels of histamine, tryptase, albumin, lysozyme, and cysteinyl-leukotrienes (third study only) in nasal lavage fluids.

RESULTS

Both concentrations of olopatadine produced significant inhibition of all nasal symptoms, compared with placebo. Olopatadine, 0.1%, inhibited lysozyme levels, but olopatadine, 0.2%, inhibited histamine, albumin, and lysozyme. The effects of olopatadine, 0.1%, were comparable to those of azelastine, 0.1%.

CONCLUSIONS

Olopatadine, at 0.1% and 0.2% concentrations, was effective in suppressing allergen-induced nasal symptoms. At 0.2%, olopatadine provided evidence suggestive of inhibition of mast cell degranulation.

Effects of fexofenadine on the early response to nasal allergen challenge

BACKGROUND

Previous studies using nasal allergen challenge models have shown that terfenadine, an H1 antihistamine, inhibits histamine release during the early response to allergen provocation. Fexofenadine, the active metabolite of terfenadine, has strong H1-antihistaminic activity and no cardiac effects. Clinical studies have documented the efficacy of fexofenadine in the treatment of allergic rhinitis.

OBJECTIVE

To determine whether fexofenadine, like terfenadine, inhibits histamine and tryptase release during the early allergic response.

METHODS

Randomized, double blind, placebo-controlled, two-way crossover study in 20 subjects with seasonal allergic rhinitis, out of their allergy season (median age 27.5 years, 13 males and 7 females). Subjects were medicated with either placebo or fexofenadine 180 mg orally daily for 1 week followed by nasal challenge with allergen. After each challenge, sneezes and nasal symptoms were recorded, and a nasal lavage was obtained for the assay of albumin, an indicator of vascular permeability, and histamine and tryptase, indicators of mast cell degranulation.

RESULTS

When patients were on placebo, allergen challenges led to significant increases in all measured parameters compared with the sham challenges with diluent. Treatment with fexofenadine resulted in inhibition of allergen-induced symptoms and increased vascular permeability, but not the release of histamine and tryptase.

CONCLUSION

Fexofenadine is an effective H1 antihistamine, but in contrast to its parent compound, terfenadine, it does not affect the release of the mast cell mediators histamine and tryptase.

Hypertonic saline nasal provocation and acoustic rhinometry

BACKGROUND

Hypertonic saline (HTS) acts as an airway irritant in human nasal mucosa by stimulating nociceptive nerves and glandular secretion. HTS does not change vascular permeability. In asthma, HTS causes airflow obstruction.

OBJECTIVE

To determine the effect of HTS on mucosal swelling using acoustic rhinometry (AcRh). Potential vasodilator effects were controlled by maximally constricting mucosal vessels with oxymetazoline (Oxy).

METHOD

Normal subjects had AcRh before and 30 min after either 0.05% Oxy or saline (0.9% NaCl) nasal treatments. Nasal provocations followed immediately with five step-wise incremental escalating doses of HTS administered at 6-min intervals. AcRh was performed 1, 3 and 5 min after each HTS administration, and then after blowing the nose at 5 min. The minimum cross-sectional area (Amin), volume of the anterior 6 cm of nasal cavity (V6) and incremental changes from pre-drug treatment baseline levels (delta, mean +/- SEM) were calculated.

RESULTS

Oxy increased Amin by 46% (delta = 0.48 +/- 0.07 cm2, P = 0.0001) and V6 by 53% (Delta = 9.9 +/- 1.5 mL, P < 1 x 10-7) during the first 30 min. Saline (vehicle) treatment had no effect. The maximum HTS dose had no effect after 1 or 3 min. However, in the 4th and 5th minutes there were reductions in Amin (delta = 0.07 +/- 0.03 cm2, P = 0.035) and V6 (delta = 1.57 +/- 0.42 mL, P = 0.004) with an increase in the weight of secretions (delta = 700 +/- 100 mg, P < 0.05). Blowing the nose returned Amin and V6 towards baseline. Oxy had no effect on HTS-induced changes in Amin, V6, pain, rhinorrhea or weight of secretions.

CONCLUSION

HTS induced nociceptive nerve stimulation and mucus secretion, and reduced V6 and Amin. Oxy caused vasoconstriction but did not alter HTS-induced effects. HTS may stimulate neurogenic axon response-mediated glandular secretion that contributes to perceptions of nasal obstruction in normal subjects.

Hot, humid air increases cellular influx during the late-phase response to nasal challenge with antigen

BACKGROUND

Inhalation of hot, humid air (HHA: 37 degrees C, > 95% relative humidity (RH)) partially inhibits the early response to nasal challenge with antigen.

OBJECTIVE

To investigate whether HHA inhibited the late-phase response to nasal challenge with antigen and increased hyper-responsiveness of the nasal mucosa to histamine.

METHODS

Twenty subjects with seasonal allergic rhinitis, outside of their allergy season, participated in a randomized, 2-way cross-over study. The subjects continuously breathed room air (25 degrees C, 30% RH) or HHA delivered via a face mask during the entire experiment. Subjects were challenged intranasally with antigen 1 h after beginning conditioning. The response was monitored by symptoms and nasal lavage at 2-h intervals after the last antigen challenge. Eight hours after antigen challenge, nasal challenge with histamine was performed.

RESULTS

Exposure to HHA significantly increased nasal mucosal temperature from baseline without affecting nasal secretion osmolality. HHA significantly inhibited antigen-induced sneezes, congestion, pruritus, and human serum albumin levels during the early response to antigen challenge. HHA exposure, however, was associated with an 8-fold increase in the eosinophil influx and a 15-fold increase in the levels of eosinophil cationic protein during the late-phase response compared to room air. There were no significant differences in nasal hyper-responsiveness to histamine during either exposure.

CONCLUSION

HHA partially decreases the early response to nasal challenge with antigen, but dramatically increases eosinophil influx. Increasing eosinophil number had no effects on the hyper-responsiveness to histamine. We speculate that the physical conditions of air differentially impact the stages of allergic inflammation.

As-needed use of fluticasone propionate nasal spray reduces symptoms of seasonal allergic rhinitis

BACKGROUND

The daily use of intranasal corticosteroids is approved for the treatment of seasonal allergic rhinitis.

OBJECTIVE

Our objective was to test the effectiveness of as-needed use of intranasal corticosteroids in the treatment of seasonal allergic rhinitis.

METHODS

A double-blind, placebo-controlled, randomized, parallel-group study of the as-needed usage of fluticasone propionate nasal spray in the management of seasonal allergic rhinitis was performed. Outcome measures were symptom score, Rhinitis Quality of Life Questionnaire (RQLQ), and the number of eosinophils and the level of eosinophilic cationic protein (ECP) in nasal lavage.

RESULTS

Twenty-six subjects in each group completed the 4-week study. The median symptom score over the duration of the study in the placebo group was 8.5 versus 4.5 in the active group. The active group had significant improvement on the interim visit in the sleep, non-nose/eye, activities, nasal, practical, and overall domains (P <.05) of the RQLQ and on the final visit in the nasal symptom domain. The number of eosinophils was significantly lower in the active than in the placebo group at the final visit. Changes in ECP were not significant.

CONCLUSION

As-needed fluticasone propionate nasal spray is efficacious in the treatment of seasonal allergic rhinitis.

Intranasal salmeterol inhibits allergen-induced vascular permeability but not mast cell activation or cellular infiltration

BACKGROUND

Salmeterol is a long-acting beta2-adrenergic agonist that is widely used in the treatment of asthma. It has been suggested that non-bronchodilator actions of salmeterol may contribute to its efficacy.

OBJECTIVE

To further evaluate the potential non-bronchodilator actions of salmeterol in vivo, using a model of nasal challenge with allergen.

METHODS

Twelve asymptomatic subjects with seasonal allergic rhinitis participated in a randomized, double-blind, placebo-controlled crossover trial of the effects of a single dose of 100 microg of salmeterol on the response to allergen challenge. Sneezing and symptom scores, and levels of histamine and albumin in nasal lavages, were measured throughout the protocol. Concentrations of tryptase, prostaglandin D2 and lysozyme were measured during the acute allergic response, while levels of IL-3, IL-5 and IL-8 were measured at later time points. Numbers of eosinophils and of total white blood cells were also recorded.

RESULTS

Salmeterol did not affect sneezing or symptom scores at any point. During the immediate response to allergen challenge, mast cell activation, reflected by concentrations of histamine, tryptase and prostaglandin D2, and serous glandular secretion, assessed by measurements of lysozyme, were unaffected by salmeterol treatment but vascular permeability, reflected by concentrations of albumin in nasal lavages, was significantly reduced. At later time points, salmeterol had no effect on levels of histamine or albumin and did not affect cellular infiltration. Concentrations of IL-3, IL-5 and IL-8 were not increased by allergen challenge in these subjects, so the effects of salmeterol could not be evaluated.

CONCLUSIONS

Treatment with a single dose of salmeterol had no effect on activation of mast cells or cellular infiltration but inhibited vascular permeability. The ability of salmeterol to inhibit antigen-induced vascular permeability may contribute to its therapeutic efficacy in asthma.

Nasal provocation with allergen induces a secondary serum IgE antibody response

The study of the IgE response to seasonal antigen exposure is limited by its occurrence once a year and by the variability of patient exposure to pollens. To overcome these problems, we investigated whether nasal challenge with antigen causes an increase in serum anti-ragweed IgE levels. We challenged individuals with ragweed allergy intranasally with nanogram quantities of ragweed antigen extract and measured their serum anti-ragweed IgE levels before and at weekly intervals after challenge. In a series of studies we found that there was a reproducible rise in antigen-specific serum IgE levels beginning the first week after challenge that plateaued at about 180% of baseline levels during the fourth week and remained elevated for 8 weeks. Not all individuals showed this response. The magnitude of the allergen-specific IgE response to nasal challenge appeared to be greater than the response to seasonal exposure. Treatment with intranasal beclomethasone before challenge did not affect the response. The results demonstrate a human in vivo model for the study of the antigen-specific secondary IgE response to allergen.

A double-blind study of the discontinuation of ragweed immunotherapy

BACKGROUND

Immunotherapy effectively treats the symptoms of allergic rhinitis and improves its pathophysiology. We studied whether the effects of immunotherapy on the early response to nasal challenge with antigen and seasonal symptoms persist after discontinuation.

METHODS

Twenty subjects with ragweed allergy who were receiving immunotherapy and who had nasal challenges performed before initiation of treatment were selected. The patients had been receiving maintenance therapy with aqueous ragweed extract at a dose of 12 microg of Amb a 1 equivalent for a minimum of 3 years, at which point they were randomized to receive either placebo injections or to continue with the maintenance dose. Nasal challenges were performed before and 1 year after randomization. Nasal challenges were monitored by counting the number of sneezes and measuring histamine, N-alpha-tosyl-L-arginine methyl ester-esterase activity, and kinins in recovered nasal lavages. In the same year symptom diaries were collected during the ragweed season.

RESULTS

The initial immunotherapy significantly reduced responses to nasal challenge in both groups. The group continuing to receive active treatment showed no significant changes from the response before randomization. In contrast, the group randomized to placebo treatment showed a partial return of histamine, kinins, and N-alpha-tosyl-L-arginine methyl ester-esterase in nasal secretions and the numbers of sneezes. IgG antibodies to ragweed declined only in the group switched to placebo treatment. Seasonal rises of IgE antibodies to ragweed did not return during the first season after treatment was stopped. Symptoms reported during the ragweed season were not different between the groups.

CONCLUSIONS

One year after discontinuation of ragweed immunotherapy, nasal challenges showed partial recrudescence of mediator responses even though reports during the season appeared to indicate continued suppression of symptoms.

In vivo diagnostic procedures: skin testing, nasal provocation, and bronchial provocation

In vivo challenge procedures can be very useful in the analysis of allergic symptoms. Skin testing has a high degree of sensitivity and specificity for determining antigens that cause allergic disease. However, positive skin tests do not necessarily indicate that a specific allergen causes symptoms specific for a certain organ. Nasal and whole lung provocation testing can help define relevant allergens that cause rhinitis or asthma symptoms. These tests are safe when performed properly under close medical supervision and have predictive values that make them useful diagnostic tools.