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.

Acute respiratory response to prolonged, moderate levels of sidestream tobacco smoke

Environmental tobacco smoke (ETS) is a significant component of indoor air pollution yet the acute upper respiratory response has not been well studied. The goal of this study was to determine the response of healthy subjects to moderate levels of sidestream tobacco smoke (SS). Twenty-three subjects were challenged on 2 separate days to clean air or SS (2 h, 15 ppm carbon monoxide, at rest). Subjects completed symptom questionnaires, posterior rhinomanometry, and body plethysmography. Average total and differential cell counts and albumin concentration were determined on nasal lavage samples. The urinary cotinine: creatinine ratio was used as a biomarker of exposure. Following SS exposure, irritant and rhinitis symptoms increased, nasal resistance rose from 4.9+/-0.4 to 6.3+/-0.6 cm H2O/L/s and specific airway conductance decreased from 0.14+/-0.01 to 0.13+/-0.01 cm H2O(-1) s(-1). Total cell counts, neutrophils, and albumin were unchanged. An increased nasal congestive response did not correlate with an increased cotinine: creatinine ratio. A history of ETS rhinitis did not predict an increased group response to smoke, but individuals with the largest physiologic and inflammatory response were historically ETS sensitive. In summary, healthy normal subjects demonstrate nasal congestion with exposure to moderate levels of SS without evidence of increased nasal vascular permeability.

Plasma extravasation through neuronal stimulation in human nasal mucosa in the setting of allergic rhinitis

We have previously shown that capsaicin nasal challenge in subjects with allergic rhinitis produces a dose-dependent increase in the albumin content of nasal lavage fluids. In the present set of studies, we determined whether this observation represents plasma extravasation that is neuronally mediated. To evaluate whether glandular secretions contribute to the albumin increase in nasal lavage fluids, volunteers with allergic rhinitis were pretreated with atropine or placebo before capsaicin challenge. Atropine significantly reduced the volume of returned lavage fluids and their lysozyme content but increased their albumin and fibrinogen content. To assess the contribution of sensory nerve stimulation, subjects with allergic rhinitis were pretreated in a second study with lidocaine or placebo before capsaicin challenge. Lidocaine significantly attenuated the capsaicin-induced increases in the volume of nasal lavage fluids, as well as their lysozyme and albumin content. To rule out the possibility of a direct effect of lidocaine on blood vessels rather than on nerves, healthy subjects were pretreated in a third study with lidocaine or placebo before bradykinin nasal challenge. Lidocaine did not affect the bradykinin-induced increase in the albumin content of nasal fluids. We conclude that, in allergic rhinitis, high-dose capsaicin induces plasma extravasation in the human nose and that this effect is neuronally mediated. This provides more definitive evidence that neurogenic inflammation can occur in vivo in the human upper airway.

Nitric oxide inhibits rhinovirus-induced cytokine production and viral replication in a human respiratory epithelial cell line

To better understand the early biochemical events that occur in human rhinovirus (HRV) infections, we examined the kinetics and mechanisms of interleukin-8 (IL-8) and IL-6 production from infected epithelial cells. Several HRV strains caused IL-8 and IL-6 production, but HRV-16 induced maximal IL-8 and IL-6 mRNA expression and protein production more rapidly than did HRV-14, despite similar rates of replication of the two viral strains. Viral induction of cytokine mRNA does not require new protein synthesis, since it was unaffected by cycloheximide treatment. The potent glucocorticoid budesonide did not affect viral replication or cytokine mRNA induction but modestly inhibited cytokine protein production. Interestingly, the nitric oxide donor 3-(2-hydroxy-2-nitroso-1-propylhydrazino)-1-propanamine (NONOate) inhibited both rhinovirus replication and cytokine production in a dose-dependent fashion without reducing levels of cytokine mRNA. The NONOate effects were due to release of nitric oxide, because NONOate that had been depleted of its nitric oxide content had no effect. Thus, nitric oxide may play an important anti-inflammatory and antiviral role in colds and nitric oxide donors may represent a novel therapeutic approach.

Activation of antiviral protein kinase leads to immunoglobulin E class switching in human B cells

An epidemiologic association between viral infections and the onset of asthma and allergy has been documented. Also, evidence from animal and human studies has suggested an increase in antigen-specific immunoglobulin E (IgE) production during viral infections, and elevated levels of IgE are characteristic of human asthma and allergy. Here, we provide molecular evidence for the roles of viral infection and of activation of the antiviral protein kinase (PKR) (double-stranded-RNA [dsRNA]-activated protein kinase) in the induction of IgE class switching. The presence of dsRNA, a known component of viral infection and an activator of PKR, induced IgE class switching as detected by the expression of germ line epsilon in the human Ramos B-cell line. Furthermore, dsRNA treatment of Ramos cells resulted in the activation of PKR and in vivo activation of the NF-kappaB complex. Interestingly, infection of Ramos cells with rhinovirus (common cold virus) serotypes 14 and 16 resulted in the induction of germ line epsilon expression. To further evaluate the role of PKR in the viral induction of IgE class switching, we infected Ramos cells with two different vaccinia virus (cowpox virus) strains. Infection with wild-type vaccinia virus failed to induce germ line epsilon expression; however, a deletion mutant of vaccinia virus (VP1080) lacking the PKR-inhibitory polypeptide E3L induced the expression of germ line epsilon. Collectively, the results of our study define a common molecular mechanism underlying the role of viral infections in IgE class switching and subsequent induction of IgE-mediated disorders such as allergy and asthma.

Influence of the cytosolic carboxyl termini of human B1 and B2 kinin receptors on receptor sequestration, ligand internalization, and signal transduction

To determine the role of the cytoplasmic carboxyl termini of human B1 and B2 kinin receptors (B1KR and B2KR, respectively) in the internalization of their respective ligands, des-Arg10-kallidin and bradykinin (BK), both wild type receptors, as well as truncated B2KRs, a mutated B2KR, and chimeric receptors were stably expressed in Chinese hamster ovary cells. Incubation of [3H]BK at 37 degrees C with cells expressing wild type B2KR resulted in pronounced and rapid ligand internalization ( approximately 80% after 10 min). By contrast, incubation of 3H-labeled des-Arg10-kallidin with cells expressing B1KR resulted in a modest, slow internalization of the ligand (<20% after 10 min). Replacement, from Cys324, of the cytoplasmic carboxyl terminus of the B2KR with that of the B1KR from Cys330 (both Cys residues are putative palmitoylation sites) greatly reduced ligand internalization ( approximately 40% after 10 min) without significantly altering Kd or ligand-induced signal activation. By marked contrast, the corresponding replacement, of the sequence from Cys330 of the cytoplasmic carboxyl terminus of the B1KR with the segment of the B2KR, led to a striking increase of ligand internalization ( approximately 75% within 10 min) without altering Kd or ligand-induced signal activation. Truncation of the B2KR to within three amino acids of Cys324 (truncation at Gly327) led to strongly reduced ligand internalization ( approximately 40% after 10 min). Truncation of the B2KR up to Lys315 almost completely abolished internalization of [3H]BK (10% after 10 min). This additional reduction is apparently not caused by the loss of the potential palmitoylation site at Cys324, since a B2KR with a point mutation of Cys324 to Ala internalized [3H]BK as rapidly as the wild type B2KR. From these results we conclude that the cytoplasmic carboxyl terminus of the human B2KR contains sequences that are necessary and sufficient to permit rapid ligand-induced sequestration of human kinin receptors and internalization of their agonists.

Comparison of nasal mucosal responsiveness to neuronal stimulation in non-allergic and allergic rhinitis: effects of capsaicin nasal challenge

BACKGROUND

Neuronal involvement has been implicated in the pathophysiology of non-allergic and allergic rhinitis, contributing to the typical exacerbation of these conditions upon exposure to non-specific environmental irritants.

OBJECTIVES

To determine if non-allergic and allergic rhinitis are characterized by increased responsiveness of the nasal mucosa to sensorineural stimulation.

METHODS

Nasal challenges with capsaicin and its vehicle were performed in three groups of subjects -- non-allergic rhinitics, perennial allergic rhinitics, and healthy controls -- and resultant symptom scores, glandular secretion reflected by lactoferrin levels, and plasma extravasation reflected by albumin levels in nasal lavage fluid were compared.

RESULTS

Capsaicin-sensitive nerve stimulation produced increases in symptom scores and lactoferrin levels which were similar among the three groups of subjects. On the other hand, only the group of subjects with allergic rhinitis demonstrated a significant capsaicin-induced increase in albumin levels and a trend in total protein levels.

CONCLUSIONS

We conclude that non-allergic rhinitis is not characterized by increased responsiveness of capsaicin-sensitive nerve fibres; while allergic rhinitis is marked by hyperresponsiveness manifested as increased albumin leakage in nasal fluids. This may reflect the activity of an axonal reflex to sensorineural stimulation.

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.

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.

Clinical and immunologic effects of component peptides in Allervax Cat

Peptides have been designed to be T cell tolerogenic for the principal allergens of the cat. These have been administered in several dosage programs to cat-sensitive patients in multicenter blinded studies. In contrast to proteins in standard extracts, IgE sensitization to peptides is an uncommon event. Pretreatment prick tests with peptides will identify the occasional sensitized patient. Other side reactions consist of allergic symptoms occurring on the day of injections. These become less severe with subsequent injections and are easily treatable with antihistamines or bronchodilators, depending on the symptoms. Treatment with cat peptides ameliorated symptoms that occur upon exposure to cats 1-6 or more weeks later. A 2-week course of 4 injections is the most effective of the regimens so far tried. T-cell-active peptides offer a promising low-risk alternative for specific treatment of respiratory allergies.

Stable expression of the human kinin B1 receptor in Chinese hamster ovary cells. Characterization of ligand binding and effector pathways

To delineate ligand binding and functional characteristics of the human B1 kinin receptor, a stable clone of Chinese hamster ovary cells expressing a single class of binding sites for [3H]des-Arg10-lysylbradykinin with a Kd of 0.3 nM and a Bmax of 38 fmol/mg protein ( approximately 40,000 receptors/cell) was isolated. Studies with peptide analogs showed that a lysine residue at position 1 (based on the lysylbradykinin sequence) of ligands was essential for high affinity binding to the human B1 receptor. In marked contrast to cloned Chinese hamster ovary cells expressing the human kinin B2 receptor, which internalized approximately 80% of the ligand within 5 min upon exposure to 2 nM [3H]bradykinin, exposure of cells expressing the B1 receptor to 1 nM [3H]des-Arg10-lysylbradykinin resulted in minimal ligand internalization. Stimulation of the B1 receptor led to inositol phosphate generation and transient increases in intracellular calcium, confirming coupling to phospholipase C, while immunoprecipitation of photoaffinity-labeled G-proteins from membranes indicated specific coupling of the receptor to Galphaq/11 and Galphai1,2. The B1, unlike the B2, receptor does not desensitize (as demonstrated by continuous phosphoinositide hydrolysis), enhancing the potential role of this receptor during inflammatory events.

Treatment with hot, humid air reduces the nasal response to allergen challenge

Ten subjects with asymptomatic seasonal allergy, outside of their allergy season, underwent allergen provocation following 1 hour of exposure to air at either 20 degrees C and 30% relative humidity (RH) or air at 37 degrees C and 90% RH. The ipsilateral changes following antigen challenge were compared under the two conditions. Conditioning of the nose to 37 degrees C, 90% RH reduced total histamine release (7.9 +/- 1.8 ng vs 4.2 +/- 1.3 ng; p < or = 0.05), sneezes (6 +/- 2 vs 3 +/- 1; p < or = 0.05), pruritus (score of 17.4 +/- 6.0 vs score of 2.0 +/- 1.8 out of a total score of 100, p < or = 0.01), nasal airway resistance (1.4 +/- 0.8 kPa/L/sec vs 0.2 +/- 0.1 kPa/L/sec; p < or = 0.05), human serum albumin levels (389.6 +/- 53.4 micrograms vs 242.2 +/- 37.9 micrograms; p < or = 0.05), and congestion (score of 23.8 +/- 4.8 vs score of 10.6 +/- 5.4 out of a total score of 100, p < or = 0.01). It had no effect on the volume of secretions (p = 0.8), lactoferrin levels (p = 0.3), or rhinorrhea (p = 1.0). Thus air at 37 degrees C and 90% RH partially reduces the early response to antigen. Its effects are greatest on histamine release, the vascular response, and neural responses, with no effect on the glandular response. The mechanisms underlying these effects are unknown.

Mechanisms of prostanoid synthesis in human synovial cells: cytokine-peptide synergism

Bradykinin (BK)2 and interleukin-1 (IL-1) interact synergistically to stimulate prostaglandin synthesis in human synovial fibroblast-like cells. The effect of BK is rapid and correlates with its capacity to elevate cytosolic levels of calcium ([Ca2+]i), while IL-1's effect is slow and s dependent upon de novo protein synthesis. The mechanism of this synergistic interaction was investigated. In the basal state, high levels of arachidonic acid (AA) were spontaneously released from synovial cells but near absent levels of cyclooxygenase activity prevented metabolism of AA to prostanoid. BK was a potent stimulus for elevating AA, but not prostaglandins, above basal levels. IL-1, in contrast, increased prostaglandins but not AA, above basal levels. IL-1 treatment was not associated with a loss or redistribution of AA among phospholipid classes. These results are consistent with high basal phospholipase activity in synovial cells and demonstrate the ability of BK, presumably via its ability to raise [Ca2+]i, to further elevate this activity(ies). Metabolism of AA to prostanoid is minimal in resting and BK-stimulated synovial cells, however, without the concomitant induction of cyclooxygenase activity by IL-1. These studies clarify the different, but synergistic, mechanisms of action of a peptide and cytokine in stimulating prostanoid synthesis in synovial cells. In addition, these data extend the results of previous investigations in demonstrating that basal phospholipase activity provides sufficient AA substrate for IL-1 induced prostanoid synthesis without invoking the concomitant induction of phospholipase activity by IL-1.

Dissociation of bradykinin-induced plasma exudation and reactivity in the peripheral airways

To determine if bradykinin, a potential mediator of asthma, acts, at least in part, at the level of the peripheral airways, we used a wedged bronchoscope technique to study asthmatic and normal subjects. Baseline peripheral airways resistance (Rp) was measured in the right upper lobe. Subjects then received saline, followed by increasing doses of bradykinin, aerosolized through the bronchoscope. Rp was measured after each challenge. At the end of the procedure, bronchoalveolar lavage was performed in both the challenged and a control segment. Fibrinogen content of recovered lavage fluids was measured as an index of plasma exudation. Bradykinin induced a dose-dependent increase in Rp in the asthmatics, but did not effect Rp in normal subjects. In asthmatics, there was no significant correlation between peripheral airways reactivity and whole lung reactivity to bradykinin. Fibronogen increased significantly in both groups after bradykinin challenge, and there was no significant difference between postchallenge levels for the two groups. Thus, hyperreactivity of the peripheral airways in asthmatics is not directly due to plasma exudation. The ability of bradykinin to increase peripheral airways resistance in asthmatic, but not in normal, subjects is consistent with a role of this peptide as a mediator of asthma.

Evidence that enhanced nasal reactivity to bradykinin in patients with symptomatic allergy is mediated by neural reflexes

OBJECTIVE

The aim of this study was to determine whether allergic inflammation induces nasal hyperreactivity to bradykinin by enhancing neuronal responsiveness.

METHODS

We compared the response to localized, unilateral nasal challenge with bradykinin in patients with perennial allergic rhinitis and nonallergic subjects, and in patients with seasonal allergic rhinitis challenged in and out of season. Weights of secretions from each nostril were recorded, and levels of albumin and lactoferrin in secretions recovered from each nostril were assayed. Contralateral administration of atropine (0.32 mg) was used to evaluate the role of cholinergic reflexes in nasal hyperresponsiveness to bradykinin.

RESULTS

In patients with symptomatic allergy, bradykinin induced greater symptom scores than in asymptomatic atopic or nonallergic control subjects. Moreover, bradykinin caused sneezing in a majority of patients with symptomatic allergy but in none of the asymptomatic atopic or nonallergic control subjects. Only patients with symptomatic allergy showed dose-dependent bilateral increases in secretion weights and levels of the serous glandular marker, lactoferrin. In contrast, bradykinin induced similar increases in ipsilateral, but not contralateral, levels of albumin in all patient populations. Atropine inhibited contralateral secretion and lactoferrin production (p < 0.05) in patients with symptomatic allergy.

CONCLUSION

The induction of sneezing and of atropine-inhibitable contralateral glandular secretion demonstrates that allergic inflammation causes nasal hyperreactivity to bradykinin, at least in part, by enhancing neuronal responsiveness.

Oral prednisone therapy in experimental rhinovirus infections

This study was designed to test the effects of oral steroid therapy on the kinin levels and symptoms of experimental rhinoviral colds. Forty-seven men were randomized to receive prednisone (20 mg) or placebo. Therapy was administered three times a day for 5 days, after one dose was given 11 hours before inoculation with rhinovirus. Viral titers, symptom scores, and kinin and albumin concentrations in nasal washes were monitored. The mean kinin levels were lower in the steroid group (287 vs 449 pg/ml, p = 0.005) with significant differences in kinin levels on days 3 and 4 (p < 0.01). No significant difference in total symptom scores was seen between the two groups. Except for increased sneezing (p < 0.01) and mucus weights (p < 0.05) on day 1 in patients treated with prednisone, there were no significant differences in individual symptom scores. Headache tended to be less prominent in steroid recipients. Mean viral titers were higher in the steroid group (1.13 vs 0.79, p = 0.03) with significant differences in the daily viral titers on days 3 (p < 0.05) and 4 (p < 0.01). Steroids reduced kinin levels in rhinoviral infections, but that reduction was not associated with a significant reduction in symptoms. This study also provides evidence for the enhancement of viral growth in steroid recipients.

Effects of loratadine and terfenadine on the induced nasal allergic reaction

OBJECTIVE

To evaluate the effect of terfenadine and loratadine on the early nasal allergic response to challenge and the subsequent cellular influx and hyperresponsiveness.

DESIGN

Double-blind, placebo-controlled, triple-crossover study.

SUBJECTS

Fourteen, asymptomatic, allergic volunteers.

INTERVENTIONS

After an initial challenge with methacholine chloride, subjects received treatment with placebo, loratadine (10 mg by mouth daily), or terfenadine (60 mg by mouth twice daily) for 1 week, followed by a nasal allergen challenge with lavages; 24 hours later, while the subjects were still receiving medication, the quantity of cells in the nasal lavage was determined, and another challenge with methacholine was done. Mediator levels were quantified in the nasal lavages after the allergen c hallenge, and the weight of the methacholine-induced nasal secretions was measured.

RESULTS

Both loratadine and terfenadine treatment resulted in significant reductions in allergen-induced sneezing and the levels of histamine, kinins, albumin, and N-alpha-tosyl-L-arginine methyl ester-esterase activity in recovered nasal lavages compared with the reductions that resulted from placebo treatment, with no significant difference among the treatments. Treatment had no effect on the levels of tryptase, prostaglandin D2 or leukotriene C4. A significant eosinophil influx into nasal secretions 24 hours after the allergen challenge in patients who were receiving placebo (P=.006) was not affected by loratidine or terfenadine treatment. Comparing methacholine-induced secretions between screening challenges and challenges with the patients who were being treated with either loratadine or terfenadine, there was a significant decrease in secretions after the use of these antihistamines (P<.05).

CONCLUSION

Both loratadine and terfenadine partially inhibit the early nasal response to allergen challenge and the subsequent reactivity to a challenge with methacholine without affecting the influx of eosinophils into nasal secretions.

Lack of effect of hot, humid air on response to nasal challenge with histamine

We have previously shown that whole body exposure of human subjects to environmental conditions of 37 degrees C and 90% relative humidity (RH) prior to and during nasal challenge with antigen decreases the early response. In this study, we evaluated 1) whether the decreased responses observed resulted from decreased end organ sensitivity to histamine and 2) whether the effect of hot, humid air persisted after the subject exited the hot, humid environment. Ten asymptomatic seasonal allergic subjects and 11 nonallergic subjects were randomized to environmental chamber conditions of either 20 degrees C, 30% RH or 37 degrees C, 90% RH for 1 hour prior to and during performance of a nasal challenge with histamine. Twenty-two hours after exiting the environmental chamber, the allergic subjects were challenged with antigen. During both chamber conditions, histamine challenge was associated with a significant increase in all measured parameters compared to sham challenge, except for the sensations of pruritus and congestion. The response to histamine challenge was not different under the two experimental conditions or between allergic and nonallergic subjects. Following both exposure conditions, allergen challenge was associated with an increase in all measured parameters compared to sham challenge, with no significant difference between the two conditions. Exposure to 37 degrees C, 90% RH minimally affects the response to nasal challenge with histamine, and thus, the previously reported decreases in the early nasal response to antigen may primarily result from reduction in mast cell activation. The effect on antigen does not persist 22 hours after exposure.

Effects of intranasal administration of endothelin-1 to allergic and nonallergic individuals

Endothelin-1 (ET-1), a 21 amino acid peptide, and its receptors are distributed in the mammalian respiratory tract. To examine the responses of human upper airways to ET-1, we investigated the effects of intranasal administration of ET-1 to nine symptomatic allergic and nine nonallergic volunteers. Paper discs were used to administer ET-1 or diluent to one side of the nasal mucosa, and to collect secretions from the ipsilateral (challenged) and contralateral (opposite) nostrils. ET-1 (0.3-10 micrograms), but not diluent, induced dose-dependent bilateral increases in secretion weights, lysozyme secretion, symptoms of rhinorrhea and itch, and sneezing in both populations. ET-1 did not induce albumin secretion, histamine release, or symptoms of nasal congestion. Compared with the nonallergic subjects, allergic individuals sneezed more and had significantly higher bilateral secretion weights, contralateral lysozyme secretion, and symptoms of rhinorrhea following ET-1 provocation. In summary, ET-1 induced symptoms relevant to inflammatory upper airway diseases in allergic and nonallergic subjects. However, responses of allergic subjects were more pronounced, particularly with respect to symptoms associated with neural reflex responses, such as sneezing and contralateral secretion. Therefore, allergic inflammation enhances responsiveness of the nasal mucosa to ET-1.

Ozone exposure in humans: inflammatory, small and peripheral airway responses

We exposed eight normal adults to filtered air (FA) and 0.35 ppm ozone (O3) and compared responses in spirometry, including isovolume (isoV) flows at intermediate-to-low lung volumes, against levels of inflammatory markers in bronchoalveolar lavage fluid (BALF) and peripheral lung resistance (Rp) measured through a wedged bronchoscope. Spirometry was performed at the end, 25 min and 24 h after exposure, bronchoscopy at 24 h after exposure. The percentages of neutrophils, fibrinogen, albumin, PGE2, PGF2 alpha, and kinins were elevated in BALF after O3 compared with FA. The percentage reduction in (isoV) FEF25-75 at 25 min and 24 h after administration of O3 correlated closely with the rise in fibrinogen concentrations in BALF, a marker of altered vascular permeability. Rp, a measurement dominated by very small or peripheral airways, was unaffected in 7 of 8 subjects. The absence of change in Rp might have reflected insufficient penetration of O3 into these airways to produce or sustain an effect for 24 h; alternatively, the bronchoscopic procedure which included atropine and lidocaine pretreatment may have reversed an O3 effect. An unexpected finding was the significant association between baseline Rp (after FA) and the magnitude of the spirometric response to O3. Our results suggest that small airway dysfunction in the immediate post-O3 period is a marker of lung inflammation.

Cold dry air-induced rhinitis: effect of inhalation and exhalation through the nose

Ten subjects with a history of cold air-induced nasal symptoms participated in a randomized two-period crossover study to evaluate the occurrence and magnitude of the reaction induced by inhalation and exhalation of cold dry air through the nose. The protocol involved breathing of either warm moist or cold dry air for 45 min at resting breathing rates. The nasal response was quantified by determining the amount of produced secretions as well as by measuring histamine and N-alpha-p-tosyl-L-arginine methyl (TAME) esterase activities in recovered nasal lavage fluids. Symptom scores were obtained. Warm moist air did not increase symptoms nor did it result in any significant changes in secretions or mediator levels. Compared with baseline, cold dry air induced significant rhinorrhea and increased both secretion weights (9.6 +/- 1.3 vs. 28.1 +/- 6.5 mg; P = 0.01) and the levels of histamine (3.9 +/- 1.2 vs. 10.6 +/- 2.7 ng/ml; P = 0.02) and TAME esterase activity (3.1 +/- 0.8 vs. 7.0 +/- 2.0 counts.min-1.10(-3); P = 0.01). We conclude that bidirectional nasal breathing of cold dry air results in a reaction that is qualitatively similar to that induced when air is only inhaled through the nose and exhaled through the mouth.

Expression of the chemokine RANTES by a human bronchial epithelial cell line. Modulation by cytokines and glucocorticoids

The chemokine RANTES is a potent chemoattractant for eosinophils, lymphocytes, and monocytes, and has been detected recently in the epithelium of human airways mucosa. We have studied, therefore, the expression of RANTES mRNA and protein in the human bronchial epithelial cell line BEAS-2B. Using Northern blot analysis, RANTES mRNA was not detectable in unstimulated BEAS-2B cells. Incubation of cells with TNF-alpha or IFN-gamma induced the expression of RANTES mRNA and protein within 16 h. The combination of TNF-alpha and IFN-gamma displayed a marked synergism in inducing RANTES expression. Pretreatment of cells with the glucocorticoid budesonide (10(-10)-10(-7) M) for 24 h inhibited expression of RANTES mRNA and protein stimulated by either TNF-alpha or TNF-alpha plus IFN-gamma in a concentration- and time-dependent manner. Nonglucocorticoid steroids did not inhibit RANTES mRNA expression. Production of RANTES by epithelium could contribute to the mechanism of selective cellular recruitment occurring in the airways during inflammation, thus playing a relevant role in the pathogenesis of diseases such as asthma, rhinitis, and polyposis. The down-regulation of RANTES production by glucocorticoids in epithelial cells may contribute to the efficacy of these compounds in reducing cellular infiltration and, ultimately, to their anti-inflammatory properties.

Inhibition of the response to nasal provocation with bradykinin by HOE-140: efficacy and duration of action

The present studies were undertaken as a first step to evaluate the potential usefulness of the bradykinin antagonist HOE-140 in delineating the role of kinins in the pathogenesis of chronic rhinitis. Intranasal single-dose administration of HOE-140, at doses up to 500 micrograms, was safe and well tolerated. Bradykinin-induced symptoms and increased vascular permeability could be inhibited, in a dose-dependent manner, by preadministration of HOE-140 5 min prior to kinin challenge. The results of dose-ranging experiments suggested that bradykinin and HOE-140 were approximately equipotent at bradykinin receptors. Preadministration of HOE-140 2 h before kinin challenge caused a significant but much weaker level of inhibition than that seen with 5-min preadministration. Comparison of data with those obtained during dose-ranging studies suggested that more than 90% of the administered HOE-140 was lost during this 2-h period. We conclude that topical HOE-140 is an effective inhibitor of the effects of bradykinin on the nasal mucosa but that the short duration of action of this drug may severely limit the utility of HOE-140 in delineating the role of kinins in the pathogenesis of chronic rhinitis.

Infection of a human respiratory epithelial cell line with rhinovirus. Induction of cytokine release and modulation of susceptibility to infection by cytokine exposure

Rhinovirus infections cause over one third of all colds and are a contributing factor to exacerbations of asthma. To gain insights into the early biochemical events that occur in infected epithelial cells, we develop, for the first time, a model in which a pure respiratory epithelial cell population can be routinely infected by rhinovirus. Viral infection was confirmed by demonstrating that viral titers of supernatants and lysates from infected cell increased with time and by PCR. Infection by rhinovirus 14 was inhibited by homotypic antiserum and by antibodies to intercellular adhesion molecule-1 (ICAM-1), the receptor for this virus. Susceptibility of epithelial cells to infection by rhinovirus 14 (but not rhinovirus 2, an ICAM-1 independent strain) can be increased by preexposure of cells to TNF alpha, whereas IFN gamma reduces susceptibility to infection by both rhinovirus strains. Rhinovirus infection per se does not markedly alter ICAM-1 expression on epithelial cells. Finally, we demonstrate that rhinovirus infection induced increased production of IL-8, IL-6, and GM-CSF from epithelial cells. Production of IL-8 correlated with viral replication during the first 24 h after infection. This model should provide useful insights into the pathogenesis of rhinovirus infections.

Expression of the chemokine RANTES by a human bronchial epithelial cell line. Modulation by cytokines and glucocorticoids

The chemokine RANTES is a potent chemoattractant for eosinophils, lymphocytes, and monocytes, and has been detected recently in the epithelium of human airways mucosa. We have studied, therefore, the expression of RANTES mRNA and protein in the human bronchial epithelial cell line BEAS-2B. Using Northern blot analysis, RANTES mRNA was not detectable in unstimulated BEAS-2B cells. Incubation of cells with TNF-alpha or IFN-gamma induced the expression of RANTES mRNA and protein within 16 h. The combination of TNF-alpha and IFN-gamma displayed a marked synergism in inducing RANTES expression. Pretreatment of cells with the glucocorticoid budesonide (10(-10)-10(-7) M) for 24 h inhibited expression of RANTES mRNA and protein stimulated by either TNF-alpha or TNF-alpha plus IFN-gamma in a concentration- and time-dependent manner. Nonglucocorticoid steroids did not inhibit RANTES mRNA expression. Production of RANTES by epithelium could contribute to the mechanism of selective cellular recruitment occurring in the airways during inflammation, thus playing a relevant role in the pathogenesis of diseases such as asthma, rhinitis, and polyposis. The down-regulation of RANTES production by glucocorticoids in epithelial cells may contribute to the efficacy of these compounds in reducing cellular infiltration and, ultimately, to their anti-inflammatory properties.

Allergen-induced hyperresponsiveness to bradykinin is more pronounced than that to methacholine

Bradykinin reduces airflow in asthmatic patients via indirect mechanism(s), possibly involving sensory nerve stimulation and increased vascular permeability. We hypothesized that allergen inhalation, which affects reactivity of nerves and vessels, would differentially alter reactivity to bradykinin and the smooth muscle spasmogen methacholine. We compared reactivity to methacholine and bradykinin 1, 2, 4, 7, 11, and 14 days after allergen provocation in 12 atopic asthmatic patients with stable baseline reactivity to bradykinin. Maximal allergen-induced shifts from baseline in reactivity were 0.73 +/- 0.12 log unit for bradykinin compared with 0.27 +/- 0.13 log units for methacholine (P = 0.0005). Nine subjects showed significant increases in bradykinin reactivity, with four subjects increasing reactivity by > 1 log unit. Moreover, the maximal mean change in bradykinin reactivity occurred 2 days postallergen. Thus, allergen-induced changes in reactivity to bradykinin and methacholine differ in magnitude and time course. Bradykinin inhalational challenge provides a sensitive index of the airway's response to allergen.

Human eosinophil-granule major basic protein and synthetic polycations induce airway hyperresponsiveness in vivo dependent on bradykinin generation

In the current series of experiments we investigated the role of bradykinin in airway hyperresponsiveness induced by human eosinophil-granule major basic protein (MBP). Bronchoalveolar lavage was performed after intratracheal instillation of MBP or poly-L-lysine in anesthetized, intubated rats, and levels of immunoreactive kinins and kallikrein-like activity were determined. Both MBP and poly-L-lysine induced a three- and eightfold increase in levels of kallikrein-like activity and i-kinins, respectively. To determine whether kinin production is required for the development of airway hyperresponsiveness induced by cationic proteins, dose-response curves to methacholine were constructed before and 1 h after intratracheal instillation of either MBP or poly-L-lysine (100 micrograms). MBP and poly-L-lysine induced an increase in airway responsiveness, which was inhibited by pretreatment with a selective BK-2 receptor antagonist, NPC 17713 (250 micrograms/ml). Our results demonstrate that MBP and poly-L-lysine activate kallikrein and stimulate the generation of i-kinins in vivo, an effect that may be related to the cationic charge of these proteins. Furthermore, the ability of these proteins to increase airway responsiveness appears to be dependent on the generation of i-kinins.

The human nasal response to capsaicin

Airway sensory nerves play a role in reactions to inhaled allergens, irritants, and physical stimuli. Capsaicin, the pungent principle of hot peppers, stimulates a subcategory of sensory nerves. To study the consequences of selective activation of airway sensory nerves in the human nose, we administered capsaicin nasal challenges to eight volunteers (four normal subjects and four subjects with perennial allergic rhinitis). Capsaicin (20 mumol/L), when sprayed into the nose, induced burning, rhinorrhea, and lacrimation. Capsaicin also induced a significant increase in total protein content of nasal lavage fluid after challenge compared with vehicle (increase from before challenge to 1 minute after challenge, 172 +/- 55 vs 46 +/- 29 micrograms/ml, p < 0.001). In contrast to many animal studies, capsaicin did not increase vascular permeability in the airway, because albumin content of nasal lavage fluid was not increased (p = 0.86). On the other hand, lactoferrin, a marker of glandular secretion, was increased (p < 0.005). Repetitive capsaicin challenge every 10 minutes led to tachyphylaxis of symptoms, total protein secretion, and lactoferrin secretion. Compared with vehicle, unilateral capsaicin (6 mmol/L) disk challenge induced significant secretion both ipsilateral (21.3 +/- 4.2 vs 4.9 +/- 2.1 mg, p < 0.01) and contralateral (18.2 +/- 4.4 vs 7.4 +/- 1.9 mg, p < 0.04) to challenge. Thus we have shown that capsaicin challenge to the human nose leads to airway sensory nerve activation. Further, we have demonstrated that capsaicin stimulates a predominantly central neuronal response and that the induced secretory response is of glandular rather than vascular origin.

Bradykinin is a potent and relatively selective stimulus for cytosolic calcium elevation in human synovial cells

Previously, we have shown that bradykinin elicits the production of prostaglandin E2 (PGE2) in human synovial cells only after pre-exposure of the cells to IL-1. The observation that calcium ionophores, but not a variety of physiologic receptor-mediated agonists, can mimic bradykinin in its synergy with IL-1 led us to hypothesize that the ability of bradykinin to induce prostanoid synthesis was a result of its selective ability (among physiologic agonists) to raise the cytosolic free ionized calcium concentration ([Ca2+]i) levels of synovial cells. Extending this hypothesis, it follows that the relative potency of an agonist in inducing PGE2 production from IL-1-treated cells should be dependent on its ability to raise [Ca2+]i. In these studies, we have confirmed the potent ability of bradykinin to elevate [Ca2+]i in resting human synovial cells. That the effect of bradykinin on [Ca2+]i was mediated through the previously described synovial cell kinin receptor was confirmed by a pharmacologic profile consistent with a high affinity B2 kinin receptor. Furthermore, the relative specificity and potency of the PGE2 response of bradykinin in IL-1-treated cells was paralleled, in resting cells, by a similar pattern in the [Ca2+]i response. Finally, IL-1 had no direct effect on [Ca2+]i levels, nor did it alter agonist-induced elevations in [Ca2+]i. We conclude that the potency of a receptor-mediated agonist in inducing prostanoid synthesis in synovial cells is dependent on its ability to raise [Ca2+]i. However, this effect is not enough, in and of itself, to induce prostanoid synthesis; the concomitant induction by IL-1 of a PG-generating enzyme is also required.

Bradykinin is a potent and relatively selective stimulus for cytosolic calcium elevation in human synovial cells

Previously, we have shown that bradykinin elicits the production of prostaglandin E2 (PGE2) in human synovial cells only after pre-exposure of the cells to IL-1. The observation that calcium ionophores, but not a variety of physiologic receptor-mediated agonists, can mimic bradykinin in its synergy with IL-1 led us to hypothesize that the ability of bradykinin to induce prostanoid synthesis was a result of its selective ability (among physiologic agonists) to raise the cytosolic free ionized calcium concentration ([Ca2+]i) levels of synovial cells. Extending this hypothesis, it follows that the relative potency of an agonist in inducing PGE2 production from IL-1-treated cells should be dependent on its ability to raise [Ca2+]i. In these studies, we have confirmed the potent ability of bradykinin to elevate [Ca2+]i in resting human synovial cells. That the effect of bradykinin on [Ca2+]i was mediated through the previously described synovial cell kinin receptor was confirmed by a pharmacologic profile consistent with a high affinity B2 kinin receptor. Furthermore, the relative specificity and potency of the PGE2 response of bradykinin in IL-1-treated cells was paralleled, in resting cells, by a similar pattern in the [Ca2+]i response. Finally, IL-1 had no direct effect on [Ca2+]i levels, nor did it alter agonist-induced elevations in [Ca2+]i. We conclude that the potency of a receptor-mediated agonist in inducing prostanoid synthesis in synovial cells is dependent on its ability to raise [Ca2+]i. However, this effect is not enough, in and of itself, to induce prostanoid synthesis; the concomitant induction by IL-1 of a PG-generating enzyme is also required.

Soluble intracellular adhesion molecule 1 in bronchoalveolar lavage fluid of allergic subjects following segmental antigen challenge

This study was undertaken to determine the relationship of soluble intercellular adhesion molecule 1 (sICAM-1) levels in bronchoalveolar lavage (BAL) fluid during allergic airway inflammation to those in the vascular compartment and to cellular components in the BAL fluids. A group of 11 allergic subjects underwent initial bronchoscopy during which a control BAL was performed and normal saline (NS) and specific antigen (Ag) were administered to two sublobar segments. A second bronchoscopy was performed 17 to 21 h later, and the NS and Ag segments were lavaged. Blood was drawn before each bronchoscopic procedure. The mean concentration of sICAM-1 in BAL fluid from NS-challenged segments was 59.2 +/- 7.6 ng/ml and was not different from that in unchallenged segments (51.5 +/- 5.6 ng/ml). In BAL fluid from Ag-challenged segments, mean concentrations of sICAM-1 increased significantly to 97.5 +/- 12.5 ng/ml. Segmental antigen challenge was associated with a small but statistically significant increase in sICAM-1 concentrations in serum. The concentrations of sICAM-1 in BAL fluid after antigen challenge exceeded levels that could be accounted for by passive transudation from the circulation, based upon the magnitude of increases in BAL albumin concentrations. The levels of sICAM-1 in BAL from Ag-challenged segments were correlated significantly with the total white cell, lymphocyte, neutrophil, and eosinophil counts in BAL fluids. These results are supportive of the notion that the local release of sICAM-1 may play a role in allergen-induced inflammatory processes in the airways.

Kinins in the pathogenesis of human airway diseases

1. Over the past decade, data have been obtained showing that the potent vasoactive peptides known as kinins are generated in airway secretions during a variety of inflammatory airway diseases, such as allergic rhinitis, viral rhinitis and asthma. Kinin generation involves release of tissue kallikrein from airway glands, as well as increased vascular permeability and activation of the plasma kallikrein system. The activity of generated kinins is regulated by a number of cell-associated, as well as plasma-derived, peptidases. 2. Kinins can induce relevant symptoms when applied to the surface of human airways. Moreover, the effects of kinins are more pronounced in the setting of chronic inflammation. In the upper airways, kinins can stimulate glandular secretion, increase vascular permeability and stimulate sensory nerves to produce symptoms of nasal obstruction, rhinorrhea, and nasal and throat irritation. In the lower airways of asthmatics, kinins are potent inducers of edema and cause bronchoconstriction by a mechanism that involves, at least in part, neural reflexes. 3. Definitive proof of a role for kinins in human airway diseases has been difficult to obtain because receptor antagonists that have been available to date have suffered from problems of potency or duration of action. Studies are continuing, however, to understand the mechanisms by which kinins exert their effects and to delineate their importance in airway diseases.

Glucocorticoids do not alter peptidase expression on a human bronchial epithelial cell line

Respiratory epithelial cell surface neutral endopeptidase 24.11 (NEP-24.11) degrades proinflammatory peptides, and it has been suggested that glucocorticoids may reduce airway inflammation, in part, by upregulation of NEP-24.11. Despite the potential importance of the epithelium as a metabolic barrier, little is known regarding what other peptidases may be present on the epithelial cell surface. Using an immortalized bronchial epithelial cell line (BEAS-2B), we have shown that human epithelial cells express no detectable angiotensin-converting enzyme, carboxypeptidase N, or dipeptidyl(amino)peptidase IV, but express significant levels of aminopeptidase M (AmM), as well as NEP-24.11. The presence of these enzymes was demonstrated via their degradation of biologically active peptides and by flow cytometry. Exposure of cells to the glucocorticoid budesonide (10(-7) M) for up to 5 days did not markedly alter the expression of NEP-24.11 or AmM, as assessed by flow cytometry, nor did glucocorticoid treatment modify rates of peptide hydrolysis by NEP-24.11 or AmM. Thus, BEAS-2B cells have both AmM and NEP-24.11 on their surface, and expression of these enzymes is not altered by glucocorticoids.

Characterization of GTP-binding proteins coupled to inhibition of adenylyl cyclase in guinea pig tracheal epithelial cells

Many important airway epithelial cell functions are regulated by intracellular cAMP. Adenylyl cyclase, the enzyme that synthesizes cAMP, is under dual regulation in many cells, but muscarinic agonists have not been shown to inhibit adenylyl cyclase in human and dog epithelial cells, despite the presence of muscarinic receptors. We question whether the lack of inhibition was related to the absence of a component of the inhibitory pathway or a lack of coupling between the components. The GTP-binding regulatory proteins (G proteins) that regulate adenylyl cyclase activity in airway epithelium have not been well characterized. We used primary cultures of guinea pig tracheal epithelial cells as a model system and identified the G proteins that modulate adenylyl cyclase activity. Immunoblot analysis demonstrated the presence of alpha subunits corresponding to stimulatory (Gs alpha) and inhibitory [Gi alpha (2) and Gi alpha (3)] G proteins as well as beta chains. These G proteins were functionally coupled to stimulation and inhibition of adenylyl cyclase in epithelial membrane preparations. Pertussis toxin-catalyzed [32P]ADP-ribosylation of Gi alpha was significantly reduced by 100 microM GTP gamma S (78.4 +/- 3.6% of control), by 100 mM NaF (41.9 +/- 9.1% of control), and by carbachol (100 microM) (29.2 +/- 9.0% of control). Atropine (10 microM) inhibited the carbachol effect by greater than 90%, suggesting that the muscarinic receptors were functionally coupled to Gi proteins. beta-Adrenergic agonists increased adenylyl cyclase activity, but muscarinic agonists failed to inhibit this enzyme. In summary, guinea pig tracheal epithelial membranes contain muscarinic receptors, Gi alpha (2) and adenylyl cyclase, which are appropriately coupled.(ABSTRACT TRUNCATED AT 250 WORDS)

Increased levels of interleukin-1 are detected in nasal secretions of volunteers during experimental rhinovirus colds

The potential involvement of interleukin-1 (IL-1) in the pathogenesis of experimental rhinovirus colds was examined. Nasal lavages were recovered before and for 5 days after rhinovirus infection from 44 subjects, 22 of whom were randomized to receive prophylaxis with glucocorticoids, while the rest received placebo. Immunoreactive IL-1 beta was significantly increased in subjects who were infected and symptomatic compared with noninfected volunteers or subjects who were infected but asymptomatic. Concentrations of immunoreactive IL-1 beta correlated with levels of kinins and albumin in lavage fluids. Studies of IL-1 bioactivity established that most activity in lavages from infected subjects was IL-1 beta. Glucocorticoid prophylaxis did not inhibit IL-1 production, nor did it significantly affect the symptomatic response to infection or, in a subset of patients, neutrophil infiltration. These data are consistent with the hypothesis that IL-1 could contribute to the pathogenesis of rhinovirus infections.

A sensitive colorimetric assay for the release of tryptase from human lung mast cells in vitro

Studies of human lung mast cells have usually focused on histamine release, although the enzymes stored in the granules may also contribute to the pathophysiology of the allergic response. We have used a simple colorimetric assay for tryptase to follow the release of proteolytic enzymes from human lung mast cells in vitro. Either human lung mast cell supernatants or authentic mast cell tryptase were mixed with benzoyl-DL-arginine-p-nitroaniline and incubated for up to 72 h at 37 degrees C. The appearance of nitroaniline was then measured at 410 nm in an ELISA plate reader. Cells were sonicated in H2O to measure total tryptase and histamine. Human lung mast cells contained the equivalent of 11.2 +/- 0.7 pg tryptase per cell and 3.2 +/- 0.3 pg of histamine. The amount of tryptase measured colorimetrically correlated with the level of tryptase measured by radioimmunoassay (Pharmacia), r = 0.92, P < 0.01. The inhibition profile of the proteolytic enzyme measured by the cleavage of BAPNA, was found to be identical to that of authentic lung mast cell tryptase. Over 90% of the maximum tryptase release was complete within 15 min whilst histamine release occurred within 5 min. In cells stimulated with 10 micrograms/ml anti-IgE we found a strong correlation between the release of tryptase and histamine, r = 0.95, P < 0.005. Finally, investigations with various pharmacological agents have supported our initial hypothesis that tryptase would mimic histamine release and provide an alternative marker for mast cell activation. In summary, we have utilised a simple enzymic assay as an indicator of human lung mast cell degranulation. In washed lung mast cells this assay appears be specific for granule tryptase and release of this activity into the supernatants of challenged cells correlates well with the presence of histamine. This assay offers several advantages over current methods of measuring mediator release from human lung mast cells in vitro and should provide an inexpensive and sensitive technique for following mast cell degranulation.

Bradykinin effects in guinea pig tracheal epithelial cells are mediated through a B2 kinin receptor and can be inhibited by the selective antagonist Hoe 140

Attempts to evaluate the role of kinins in airway inflammation in humans using the bradykinin receptor antagonist [DArg0-Hyp3-DPhe7]-bradykinin (NPC 567) were unsuccessful, possibly because of the low potency and poor stability of this compound. Recently, [DArg0-Hyp3-Thi5-DTic7-Oic8]-bradykinin (Hoe 140), a novel antagonist that seems to overcome these weaknesses, has been developed. The present study was performed to compare the potency and efficacy of Hoe 140 to those of NPC 567 and another antagonist, [DArg0-Hyp3-DPhe7-Ile8]-bradykinin (B7418), on kinin receptors on guinea pig tracheal epithelial cells. Radioligand binding studies showed the presence of two types of B2 kinin receptors on guinea pig tracheal epithelial cells: a high-affinity site with a Kd of 0.44 nM and Bmax of 12.1 fmol/10(6) cells (4000 sites/cell), and a lower affinity site with a Kd of 10 nM and Bmax of 16 fmol/10(6) cells (9600 sites/cell). Bradykinin-induced prostaglandin E2 production seemed to be associated primarily with the lower affinity site. All three B2 receptor antagonists displaced labeled bradykinin from both classes of binding sites and inhibited bradykinin-induced prostaglandin E2 production, but Hoe 140 was up to 40-fold more potent than NPC 567 and showed an affinity comparable to that of bradykinin for both binding sites. This higher potency of Hoe 140, and its stability against peptidases, suggests that this compound will be useful in evaluating the role of bradykinin in inflammatory diseases of the airways.

Localization of immunoreactive tissue kallikrein in human trachea

Tissue kallikrein is the major kininogenase detected in bronchoalveolar lavage fluids from asthmatics and may play a particularly important role in kinin generation during asthma. The present study was undertaken to determine the source of tissue kallikrein in the human lower airways. Specific antisera to human tissue kallikrein were used to localize this enzyme by immunocytochemistry in human trachea. Immunoreactive tissue kallikrein was localized in submucosal glands of the lamina propria but was not detected in epithelial cells or goblet cells. Specific staining for tissue kallikrein was not detected in all cells of the submucosal glands but was restricted to cells forming demilunes in the distal portions of the glands. When consecutive serial sections of submucosal glands were alternately stained using antiserum to tissue kallikrein and a periodic acid Schiff stain (to detect mucus), it was revealed that immunoreactive tissue kallikrein was present only in serous cells and not in mucus cells. The localization of tissue kallikrein to the serous cells of submucosal glands should facilitate studies to regulate the release of this enzyme. Regulation of tissue kallikrein release may provide a mechanism to reduce kinin generation during asthma.

Intranasal beclomethasone inhibits antigen-induced nasal hyperresponsiveness to histamine

To determine whether intranasal steroid treatment inhibits the increased sensitivity to histamine that occurs 24 hours after nasal antigen challenge, 12 allergic volunteers were entered into a double-blind study comparing placebo or 164 micrograms of beclomethasone dipropionate twice a day for 7 days. Beclomethasone dipropionate partially reduced the early mediator response to antigen and the influx of eosinophils 24 hours later. Comparing the initial histamine challenge with that done 24 hours after antigen with the subjects on placebo, there was a significant increase in sneezes, TAME-esterase activity, and albumin. Pretreatment with intranasal beclomethasone dipropionate resulted in a reduced response to histamine 24 hours after antigen challenge. A positive correlation occurred between the number of eosinophils in the lavage before histamine challenge and the level of TAME-esterase activity (rs = 0.67, p = 0.03) during the histamine challenge that followed antigen with the subjects on placebo. We thus confirmed the increase in nonspecific nasal airway responsiveness 24 hours after antigen challenge, with a concomitant increase in eosinophils, and demonstrate its inhibition by pretreatment with intranasal steroids.

Cultured human synovial fibroblasts rapidly metabolize kinins and neuropeptides

Kinins and substance P have been implicated in the pathogenesis of inflammatory arthritis by virtue of their abilities to induce vasodilation, edema, and pain. The relative biological potencies of these peptides in vivo would depend at least in part upon their rates of catabolism in the joint. We hypothesized that human synovial lining cells may regulate intraarticular levels of kinins and neuropeptides via degradation by cell surface-associated peptidases. We exposed intact human synovial fibroblasts to kinins and substance P, in the presence or absence of specific peptidase inhibitors, and measured the amount of intact substrate remaining and degradation product(s) generated over time. Aminopeptidase M (AmM; EC 3.4.11.2), neutral endopeptidase-24.11 (NEP-24.11; EC 3.4.24.11), and dipeptidyl(amino)peptidase IV (DAP IV; EC 3.4.14.5) were identified on the cell surface of synovial cells. Bradykinin degradation was due entirely to NEP-24.11 (1.39 +/- 0.29 nmol/min per well). Lysylbradykinin was also degraded by NEP-24.11 (0.80 +/- 0.19 nmol/min per well); however, in the presence of phosphoramidon, AmM-mediated conversion to bradykinin (3.74 +/- 0.46 nmol/min per well) could be demonstrated. The combined actions of NEP-24.11 (0.93 +/- 0.15 nmol/min per well) and DAP IV (0.84 +/- 0.18 nmol/min per well) were responsible for the degradation of substance P. AmM (2.44 +/- 0.33 nmol/min per well) and NEP-24.11 (1.30 +/- 0.45 nmol/min per well) were responsible for the degradation of the opioid peptide, [Leu5]enkephalin. The identity of each of the three peptidases was confirmed via synthetic substrate hydrolysis, inhibition profile, and immunological identification. The profiles of peptidase enzymes identified in cells derived from rheumatoid and osteoarthritic joints were identical. These data demonstrate the human synovial fibroblast to be a rich source of three specific peptidases and suggest that it may play a prominent role in regulating peptide levels in the joint.

Local application of atropine attenuates the upper airway reaction to cold, dry air

In some individuals, inhalation of cold, dry air (CDA) provokes symptoms of rhinitis, accompanied by an increase in the levels of inflammatory mediators and markers of plasma leakage of recovered nasal lavages. Because rhinorrhea is a major component of this reaction and because nasal glands are heavily innervated by the parasympathetic system, we assessed the effect of atropine on the nasal reaction to CDA. Using a double-blind, randomized, crossover design, we administered a total dose of 0.5 mg of atropine or placebo intranasally to 18 volunteers before provocation with CDA. The reaction was monitored with symptom scores and by measuring the concentrations of histamine, N-alpha-p-tosyl-L-arginine methyl ester (TAME)-esterase activity and albumin, as well as the osmolality of lavage fluids before and after the provocation. Atropine significantly reduced rhinorrhea, the levels of histamine, and TAME-esterase activity as well as the osmolality of recovered lavage fluids, but had no effect on nasal congestion or albumin. Even with atropine, however, rhinorrhea and TAME-esterase activity were still significantly increased over the prechallenge baseline. Our results demonstrate that atropine-sensitive parasympathetic efferent pathways contribute to the CDA-induced rhinitis. We speculate that (1) the glandular and the vascular events of the upper airway reaction to dry air have different pathophysiologic mechanisms; (2) a significant component of TAME-esterase activity in lavage fluids may be of glandular origin; and (3) in addition to parasympathetic nerve activation, other mechanisms are involved in the upper airway reaction to dry air. The mechanism(s) leading to the reduction of histamine is unknown.

The nasal response to histamine challenge: effect of the pollen season and immunotherapy

To evaluate changes in the nasal response to histamine, we challenged 19 subjects with allergic rhinitis caused by ragweed (RW) before, during, and after the RW season with increasing doses of histamine diphosphate. We compared their response, as measured by symptoms and the levels of TAME-esterase activity and albumin recovered in the nasal lavage fluid, with response of two groups with allergic rhinitis undergoing immunotherapy with moderate-dose (N = 16) and high-dose (N = 11) RW (2 and 24 micrograms of antigen E [Amb a I] as maintenance dose, respectively). Four challenges with histamine were performed in each group: before, at the peak of, near the end of, and 2 weeks after the RW season. The three groups of subjects had similar skin sensitivity to antigen and levels of TAME-esterase activity and albumin recovered from nasal lavages after histamine challenge performed before seasonal exposure. Symptom diaries obtained throughout the season revealed a significant reduction only in the high-dose immunotherapy-treated group. At the peak of the season, the untreated group had more symptoms in response to the challenge compared with the challenges before and after the season (p = 0.04 for both groups). The saline challenge occurring before challenging with histamine also demonstrated a significant increase at the peak of the season compared with increases before the season (p = 0.02). This observation was also true for the levels of albumin and TAME-esterase activity. If the response after saline challenge was subtracted from each response after histamine challenge, no difference was found in the results between any of the visits.(ABSTRACT TRUNCATED AT 250 WORDS)

Tryptase and histamine as markers to evaluate mast cell activation during the responses to nasal challenge with allergen, cold, dry air, and hyperosmolar solutions

We have used assays for histamine and for the specific mast cell enzyme, tryptase, to examine the response of the nasal mucosa to provocation with several different stimuli and to evaluate the reliability of histamine as a marker of mast cell activation. High levels of histamine detected in baseline lavages of some subjects are not associated with any detectable tryptase, suggesting they are not mast cell derived. During pronounced immediate allergic responses, however, mast cell degranulation clearly occurs, and a striking correlation between histamine and tryptase is observed. This correlation is weaker when a more modest allergic response is induced, possibly reflecting differential diffusion of the two mediators across the epithelium. Provocation of susceptible individuals with cold, dry air leads to increased recoveries of both histamine and tryptase, confirming that mast cell degranulation occurs during this reaction. Although hyperosmolarity of the nasal mucosa may contribute to mast cell degranulation induced by cold, dry air, a brief exposure of the nasal cavity to hyperosmolar mannitol was not associated with measurable production of tryptase. The combined use of histamine and tryptase measurements can therefore provide useful evidence regarding the role of mast cell activation in the pathogenesis of inflammatory responses.

Elevation of tissue kallikrein and kinin in the airways of asthmatic subjects after endobronchial allergen challenge

Bronchial tissue kallikrein is the major kininogenase activity in the airways of asthmatic subjects. The relationship of IgE-mediated events to its release and/or activation is unknown, however, and is the subject of this report. Seven subjects with mild atopic asthma underwent endobronchial challenge with relevant aeroallergen. Baseline pre-allergen lavage and sequential post-challenge lavages were collected over an approximate 10-minute time course. Individual aliquots were analyzed separately and compared with saline control lavages performed in a separate lobe. In five of the seven subjects, an increase in tissue kallikrein activity, measured by cleavage of the synthetic substrate Val-Leu-Arg-pNA, was identified in the post-challenge lavages. The antigenic identity of the enzymatic activity was confirmed as a tissue kallikrein in each case by immunoblotting. Tissue kallikrein activity was highly correlated with the appearance of immunoreactive histamine and kinin (p = 0.0001). High molecular weight kininogen influx and cleavage was detected in the post-challenge samples by immunoblotting and paralleled the detection of kinin in BAL fluid. Two of the subjects, despite clinical profiles similar to those of the five positive responders, failed to react to endobronchial challenge. Saline control lavages contained detectable kallikrein, kinin, and histamine in two subjects; in each case, however, this was significantly less than in the post-allergen samples. The results demonstrate a close association between immediate type hypersensitivity events in the lower airway and the appearance of active kallikrein, kininogen substrate, and the liberation of kinin.

Evaluation of a bedtime dose of a combination antihistamine/analgesic/decongestant product on antigen challenge the next morning

The effects of CAAD (diphenhydramine hydrochloride, 50 mg; pseudoephedrine hydrochloride, 60 mg; acetaminophen, 1 g in 10% ethanol) were evaluated in a double-blind, three-way, placebo-controlled, cross-over study on 18 volunteers with allergic rhinitis. The number of sneezes following nasal challenge with antigen was significantly reduced after a bed-time dose of CAAD (P less than .005) and a single dose of diphenhydramine (P less than .001) given 2 hours before the challenge. The levels of N-alpha-tosyl-L-arginine methyl ester (TAME) activity decreased after diphenhydramine treatment, while histamine levels following challenge were not different. The drowsiness reported after CAAD was equal to placebo, but significantly less than diphenhydramine (P less than .002 for both). The active treatments reduced the actions of histamine without suppressing its release from mast cells. The effect of CAAD persists 10 hours after administration without inducing drowsiness.

Platelet activation in the lung after antigen challenge in a model of allergic asthma

The purpose of this study was to investigate whether platelets are activated and release their products in the human lung after antigen challenge. Using subsegmental antigen challenge as a model of asthma, bronchoalveolar lavage fluids from ragweed-allergic asthmatic subjects were assayed for the alpha granule products, platelet factor 4 (PF4) and beta-thromboglobulin (beta-TG), prior to challenge (baseline) and at 5 min and 19 h after challenge with ragweed antigen. Airway segments challenged with normal saline were used as controls. Five minutes after antigen challenge, levels of platelet products in BAL fluid were not elevated from baseline or normal saline control levels. However, 19 h after antigen challenge, a 10-fold increase in platelet products in BAL fluids was found. The mean PF4 levels increased from baseline and saline control values of less than 1.0 to 7.2 ng/ml (p less than 0.05) 19 h after antigen challenge. beta-TG increased from baseline and control levels of less than 1.0 to 6.6 ng/ml (p less than 0.05). Elevations in PF4 and beta-TG were highly correlated with each other (r = 0.98, p less than 0.0001). Levels of platelet products during the 19-h response correlated with albumin, with kinins, with the prostaglandins 6-keto-PGF1 alpha, PGE2, and PGF2 alpha, and with the eosinophil-derived proteins, eosinophil-derived neurotoxin and eosinophil peroxidase. We conclude that platelet activation in the lung is a feature of the late inflammatory response to antigen challenge and that platelets may play an important role in allergic inflammation and asthma.

The effect of azelastine on the early allergic response

To study the effect of azelastine on the immediate reaction to nasal allergen challenge, we performed a double blind, placebo-controlled cross-over clinical trial. Thirteen subjects with seasonal allergic rhinitis underwent nasal challenge with antigen 4 hr after a single oral 2 mg dose of azelastine. The response was monitored by counting the number of sneezes and by measuring the levels of histamine, prostaglandin D2, immunoreactive sulphidopeptide leukotrienes, kinis and TAME-esterase activity in recovered nasal lavages. After a single dose of azelastine, there was a significant reduction in sneezing (10 vs 2, P = 0.01) and in the median levels of recovered TAME-esterase activity (63.1 vs 17.5 c.p.m. x 10(-3), P = 0.01), immunoreactive sulphidopeptide leukotrienes (7.5 vs 2.1 ng/ml, P = 0.03) and kinins (1370 vs 251 pg/ml, P = 0.03), with no significant reduction in the median levels of histamine (3.7 vs 1.2 ng/ml, P = 0.2) and prostaglandin D2 (70 vs 70 pg/ml, P = 0.2) compared to placebo (numbers represent total increase over diluent challenge). These results suggest that azelastine does not inhibit mast cell activation but affects the consequences of released histamine, namely sneezing, increased vascular permeability and the generation of kinins. The results further suggest that other cells, in addition to mast cells, might be responsible for the generation of leukotrienes during the early allergic response, and that azelastine reduces their ability to generate this mediator or that inhibition of leukotriene release from mast cells occurs at lower drug concentrations.