Do nasal mast cells release histamine on stimulation with substance P in allergic rhinitis?

Females have stronger neurogenic response than males after non-specific nasal challenge in patients with seasonal allergic rhinitis

Epidemiological studies show female predominance in the prevalence of non- allergic rhinitis (NAR) and local allergic rhinitis (LAR). Experimental studies show female patients with allergic rhinitis (AR) demonstrate higher levels of sensitivity to irritants and airway hyperresponsiveness than males. Bronchial asthma shows female predominance in post-puberty patients, and gender interaction with severe asthma endotypes. Fibromyalgia, chronic fatigue syndrome, migraine and chronic cough, syndromes, which are commonly related to neurokinin substance P (SP) in the literature, also show strong female predominance. Studies have demonstrated that sex hormones, primarily oestrogens, affect mast cell activation. Mast cell proteases can amplify neurogenic inflammatory responses including the release of SP. Based on human epidemiological data and animal experimental data we hypothesized that female patients have different interaction between mast cell activation and neurogenic inflammation, i.e. substance P release, resulting in a different nasal symptom profile. To test the hypothesis we performed allergen and non-specific nasal challenges in patients with seasonal allergic rhinitis (SAR) out of season and looked for gender differences in subjective and objective responses. The interaction between subjective and objective reactivity was evaluated through the comparison of subjective symptom scores, concentrations of neurokinin substance P (SP) and cellular markers in nasal lavages after low doses of nasal allergen challenges. Female allergic subjects tended to have higher substance P (SP) concentrations both before and after non-specific challenges. The difference between post-allergen and post - hypertonic saline (HTS) challenge was highly significant in female patients (p = 0.001), while insignificant in male subjects (p = 0.14). Female patients had significantly stronger burning sensation after HTS challenge than male. These data indicate difference in the interaction between inflammatory cells and the neurogenic response, which is gender- related, and which may affect symptom profiles after challenges. Different regulation of neurogenic inflammation in females may have impact on symptoms and endotyping in respiratory disorders, not only in allergic rhinitis, but also asthma, chronic rhinosinusitis and irritant -induced cough.

Role of substance P in allergic nasal symptoms in rats

The present study was undertaken to investigate the pathological role of substance P in allergic nasal symptoms in rats. The topical application of substance P caused an increase in the incidence of sneezing and nasal rubbing in a dose-dependent fashion, and at a dose of 30 nM/site it showed a significant effect. L-732,138, a tachykinin NK(1) receptor antagonist, at doses of 3 and 10 mg/kg showed a significant inhibition of the nasal signs induced by exogenous substance P in rats. In addition, L-732,138 also showed a significant inhibition of nasal behavior induced by antigen in actively sensitized rats at the same dose. On the other hand, histamine H(1) receptor antagonists, such as cyproheptadine, epinastine and olopatadine had no effect on the nasal behaviors induced by exogenous substance P, even at higher doses, indicating that exogenous substance P does not cause the degranulation of mucosal mast cells in the rat. Moreover, all the histamine H(1) receptor antagonists showed the dose-dependent inhibition of the nasal signs induced by antigen in actively sensitized rats, which revealed that the inhibition of these drugs was exhibited through the antagonistic effect on histamine H(1) receptors. Therefore, from these results, it is reasonable to conclude that substance P released from the nasal mucosa through the activation of tachykinin NK(1) receptors during the antigen antibody reaction plays an important role in allergic nasal symptoms.

Neuropeptide immunofluorescence in human nasal mucosa: assessment of the technique for vasoactive intestinal peptide (VIP)

Neuropeptides are important neurotransmitters in nasal physiology and the increasing knowledge of their role in nasal diseases brings new therapeutic perspectives. The investigation of human nasal mucosa neuropeptides is based mostly on immunocytochemistry, a complex approach whose resulting factors may be variable. Aiming to make this kind of research available, an immunofluorescence approach for vasoactive intestinal peptide (VIP) in human nasal mucosa is proposed and evaluated.

Study design

Transversal cohort.

Material and Method

Human inferior turbinate samples were obtained at time of nasal surgery from eight patients. The samples were fixed in Zamboni solution (4% phosphate-buffered paraformaldehyde and 0.4% picric acid), snap-frozen and stored at -70ºC. 14 µm sections were then obtained. Immunofluorescence staining for VIP (Peninsula Laboratories) was performed and its images documented by conventional photography. The method's specificity, sensitivity and reproducibility of execution were evaluated. Additionally, the reproducibility of interpretation of results was evaluated through the comparison of staining scores (0 to 4) attributed to the images by six observers.

Results

The results showed the approach to be very specific and sensible, besides being reproducible in its execution. The interpretation of results may depend on the observer's accuracy in judging immunofluorescence images, but it showed uniformity.

Conclusion

The proposed method was highly useful for research purposes in neuropeptides in human nasal mucosa.

Expression of substance P and vanilloid receptor (VR1) in trigeminal sensory neurons projecting to the mouse nasal mucosa

Substance P and neurokinin A (NKA) have potent pro-inflammatory effects in the airways. The release of these neuropeptides from primary afferent (sensory) nerve endings to various stimuli is considered to be induced by activation of the capsaicin (vanilloid) receptor (VR1). In this study, retrograde neuronal tracing studies were combined with immunohistochemistry for VR1 and substance P to investigate the occurrence and distribution of substance P and VR1 receptor expression in mouse trigeminal neurons that were identified by retrograde labeling with Fast blue dye from the nasal mucosa. Fast blue signaling was observed in mucosa layers of the right nasal cavity and in sensory trigeminal neurons close to the division of the ophthalmic and maxillary nerve. Expression patterns of VR1 and substance P were found with different frequencies: 11.3+/-1.2% (mean+/-SEM) were immunoreactive for VR1, 4.9+/-1.1% for VR1 and SP, and 6.4+/-1.3% only for VR1 but not for SP. These VR1-positive neurons were partly binding to lectin I-B4, indicating VR1-expression in non-peptidergic upper airway C-fibers. In conclusion, based on the extent of SP and VR1 co-localization in nasal afferent neurons, the present study suggests that, following a peripheral activation of the VR1 receptor on SP afferents, there could be a triggering of SP-mediated phenomena, including those related to inflammation, such as plasma extravasation.

Efficacy of azelastine nasal spray in the treatment of vasomotor (perennial nonallergic) rhinitis

BACKGROUND

Azelastine hydrochloride is an antihistamine with anti-inflammatory properties that is available in the United States in a nasal spray formulation for the treatment of seasonal allergic rhinitis. Vasomotor (perennial nonallergic) rhinitis (VMR) is a noninfectious, chronic rhinitis usually not associated with inflammatory cell infiltration.

OBJECTIVE

Two multicenter, randomized, double-blind, placebo-controlled, parallel-group clinical trials were conducted to determine whether patients with symptoms of VMR (rhinorrhea, sneezing, postnasal drip, and nasal congestion) could be effectively treated with azelastine nasal spray.

METHODS

All of the patients who participated in the trials had a diagnosis of VMR, symptoms for at least 1 year, negative skin tests for a mixed panel of seasonal and perennial allergens, and a nasal cytology examination negative for eosinophils. After a 1-week, single-blind, placebo lead-in period, patients who met the symptom severity qualification criteria were randomized to receive either azelastine nasal spray (two sprays per nostril twice daily, 1.1 mg/day) or placebo nasal spray for 21 days. Patients recorded the severity of their VMR symptoms on diary cards each morning and evening of the trial using a four-point symptom rating scale (0 = none to 3 = severe). The primary efficacy variable was the overall reduction from baseline in the total vasomotor rhinitis symptom score (TVRSS) over the 21-day, double-blind treatment period.

RESULTS

In both studies, azelastine nasal spray significantly (study 1, P = .002; study 2, P = .005) reduced the TVRSS from baseline when compared with placebo. Significant improvement was observed within the first week and improvement in all symptoms favored treatment with azelastine nasal spray. No serious or unexpected adverse events were reported in either study. Bitter taste (19% vs 2%) was the only adverse experience that occurred with a statistically significantly greater incidence in the azelastine group than in the placebo group.

CONCLUSIONS

This is the first demonstration of the efficacy of an antihistamine in the therapy of VMR in two double-blind, placebo-controlled clinical trials.

Dose-dependent effects of capsaicin nasal challenge: in vivo evidence of human airway neurogenic inflammation

BACKGROUND

Nerve involvement has been implicated in the pathophysiology of chronic respiratory inflammatory diseases. Peptidergic nerve stimulation has been shown to induce leukocyte activation and plasma extravasation in the airways of various animal species. The occurrence of this phenomenon of neurogenic inflammation in the human airway, however, has not been established.

OBJECTIVE

We conducted this study to determine whether neuronal stimulation can induce reproducible and dose-dependent inflammatory changes in the human upper airway.

METHODS

Ten volunteers with active allergic rhinitis participated in the study. Capsaicin, the pungent component of hot pepper that specifically stimulates afferent nerve fibers, was administered by means of nasal spray in doses of 1 microg, 10 microg, and 100 microg in a double-blind, randomized, crossover manner with 1 week between doses. Symptom scores before and after capsaicin nasal challenge were recorded by using visual analog scales. Nasal lavage fluids collected before and at 30 minutes, 1 hour, and 4 hours after capsaicin challenge were analyzed for leukocyte counts; albumin and lysozyme levels were measured to evaluate effects on plasma leakage and gland secretion, respectively.

RESULTS

Capsaicin nasal challenge produced symptoms of burning, congestion, and rhinorrhea. Leukocyte counts or albumin and lysozyme levels were not significantly increased after administration of 1 microg of capsaicin at any time point. On the other hand, there were significant increases in leukocyte counts 1 hour (p < 0.05) and 4 hours (p = 0.008) after 10 microg of capsaicin and 30 minutes (p = 0.009), 1 hour (p = 0.007), and 4 hours (p = 0.007) after 100 microg of capsaicin. Albumin and lysozyme levels were both significantly increased 30 minutes after 10 microg and 100 microg of capsaicin (p = 0.005 for both). Comparison of changes in symptom scores, leukocyte counts, and albumin and lysozyme levels among the three capsaicin challenges indicated generally increasing effects with higher capsaicin doses.

CONCLUSION

Capsaicin-sensitive nerve stimulation in subjects with active allergic rhinitis produces reproducible and dose-dependent leukocyte influx, albumin leakage, and glandular secretion. These results provide in vivo evidence for the occurrence of neurogenic inflammation in the human upper airway with active allergic disease.

Onset of action in the nasal antihistaminic effect of cetirizine and loratadine in patients with allergic rhinitis

Several studies have compared the cutaneous efficacy of cetirizine and loratadine and their onset of action. We assessed the nasal effect of these two antihistamines in a randomized, double-blind, crossover, placebo-controlled trial in order to compare objectively their efficacy and onset of action in the noses of patients with allergic rhinitis. Nasal challenge was performed by nebulization of increasing doubling doses of histamine (0, 0.04-1.28 mg/nostril) in 12 patients (eight men, four women, aged 22-39 years). Nasal airway resistance (NAR) was measured by posterior rhinomanometry either 1.5 h or 4 h after intake of cetirizine (10 mg), loratadine (10 mg), or placebo. Baseline NAR was identical between all study days (2.60-2.88 cmH2O.l-1.s). One and a half hours after intake, the increase in NAR induced by histamine was significantly reduced by both cetirizine and loratadine in contrast to placebo. However, with cetirizine the nasal obstruction was significantly lower than with loratadine (P < 0.05). Four hours after intake, a similar inhibition of the nasal obstruction caused by histamine was observed with both cetirizine and loratadine (P < 0.05). In conclusion, this study found cetirizine and loratadine to have similar nasal efficacy at therapeutic dosage 4 h after intake, whereas cetirizine was more effective than loratadine 1.5 h after intake. In agreement with the results observed in the skin, our study suggests a more rapid onset of action of cetirizine in the nose in allergic rhinitis.

Tachykinin and kinin receptor antagonists: therapeutic perspectives in allergic airway disease

The morbidity of allergic airway disease and the number of deaths resulting from it have not declined in the past ten years. The multiplicity of mediators released in the acute allergic reaction and our limited knowledge of the basic mechanisms that drive chronic inflammation have hampered the design of effective therapeutic regimens for this type of disease. In this article, Claude Bertrand and Pierangelo Geppetti summarize recent studies in which new, potent and selective tachykinin and kinin receptor antagonists demonstrate the involvement of tachykinins and kinins in airway anaphylaxis, and review how these antagonists might be of use in treating allergic asthma and rhinitis.

Selective recruitment of eosinophils by substance P after repeated allergen exposure in allergic rhinitis

We have investigated the nasal response to substance P after pollen exposure in seasonal allergic rhinitic patients. Seven patients with strictly seasonal allergic rhinitis were studied during the pollen season, 24 h after nasal challenge with pollen. They received increasing doses of nebulized substance P (0 to 80 nmol) in each nostril. Responses were assessed by measurement of nasal airway resistance by posterior rhinomanometry and quantification of albumin, histamine, and inflammatory cells in the nasal lavage fluid. Nasal airway resistance increased in a dose-dependent manner after substance P challenge. Protein and albumin in nasal lavage fluids increased after administration of substance P: from 2.6 +/- 0.3 to 6.8 +/- 1.1 mg for protein (P < 0.01) and from 0.2 +/- 0.1 to 3.1 +/- 0.6 mg for albumin (P < 0.02). Expressed as a percentage of total protein, albumin increased from 10.5 +/- 3.6% to 39.9 +/- 3.5% (P < 0.02), suggesting occurrence of plasma leakage. No histamine release was observed after challenge with substance P. Total cell counts significantly increased from 11.4 +/- 2.4 to 41.8 +/- 17.3 x 10(3) cells/ml after substance P (P < 0.05). Eosinophils were already numerous before substance P challenge (2.1 +/- 0.7 x 10(3) cells/ml), and the number of eosinophils markedly increased in all patients after substance P (for the whole group, 25.8 +/- 13.3 cells/ml, P < 0.05). In contrast, the number of neutrophils only slightly increased in five patients, and changes did not reach significance for the group as a whole. Our results show that substance P induces nasal obstruction and albumin extrusion in allergic rhinitic patients after repeated pollen exposure. These vascular phenomena are associated with recruitment of eosinophils. Since substance P is known to be released after nasal allergen challenge, our data suggest a role for substance P in the chronic eosinophilic inflammation of the nasal mucosa observed in symptomatic allergic rhinitis.