[Mechanisms of action of glucocorticoids. Application to the treatment of respiratory inflammation].
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Drug Resistance↗
Biomedical subjects
J Mullol
Publications and source records attributed to J Mullol.
Cytokine gene expression and release from epithelial cells. A comparison study between healthy nasal mucosa and nasal polyps.
BACKGROUND: Epithelial cells release cytokines and they probably contribute to chronic inflammation detected in bronchial asthma, rhinitis and nasal polyposis. OBJECTIVES: To investigate the effect of cultures on cytokine gene expression to compare epithelial cell cytokine release by both healthy nasal nucosa (HNM) and nasal polyps (NP), and the modulation by dexamethasone and to investigate which cytokines may promote eosinophil survival. METHODS: Epithelials cells were cultured to confluence, human epithelial cell conditioned media generated with or without dexamethasone, and supernatants measured by ELISA. Cytokine gene expression was investigated by reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: Fresh epithelial cells only expressed mRNA for intesleukin-8 (IL-8) and granulocyte macrophage-colony stimulating factor (GM-CSF) while cultured cells expressed mRNA for IL-1 beta, IL-6, IL-8, tumour necrosis factor-alpha (TNF alpha) and GM-CSF. Epithelial cells from NP significantly (P < 0.05) released more IL-8 (25431 +/- 3163 pg/mL), and GM-CSF (1229 +/- 391 pg/mL) than those from HNM (18604 +/- 1723 pg/mL for IL-8; and 611 +/- 98 pg/mL for GM-CSF). Dexamethasone 10 microM inhibited the release of all cytokines, this effect being similar (40-50%) in both HNM and NP, except for IL-6 which was higher in HNM. Eosinophil survival induced by epithelial cell secretions from both HNM and NP was strongly blocked by GM-CSF antibody while it was partially blocked by antibodies to TNF alpha and IL-8. CONCLUSIONS: These findings suggest that although epithelial cell culture procedures may upregulate cytokine gene expression, nasal polyps may represent a more active inflammatory tissue by releasing more cytokines than healthy nasal mucosa this release being inhibited by steroids; and that, in addition to GM-CSF, other cytokines such as TNF alpha and IL-8, may also be involved in the promotion of eosinophil survival.
Base Sequence↗
Comparative study of the effects of different glucocorticosteroids on eosinophil survival primed by cultured epithelial cell supernatants obtained from nasal mucosa and nasal polyps.
BACKGROUND: Supernatants from epithelial cell cultures enhance eosinophil survival in vitro, this effect being abrogated by previous incubation of eosinophils with glucocorticosteroids. This property has resulted in the development of an in vitro test to compare the potency of these drugs. A comparative study was performed with dexamethasone, methylprednisolone, deflazacort, and budesonide. METHODS: Human epithelial cell conditioned media (HECM) was generated from cultured epithelial cells obtained from healthy nasal mucosa and polyps. Eosinophils isolated from the peripheral blood were incubated with different corticosteroids for one hour before the addition of HECM. The inhibitory potency of the four steroids on the eosinophil survival index was compared using the concentration of steroid causing 50% inhibition (IC50). RESULTS: Eosinophil survival was increased by HECM from both healthy nasal mucosa and polyps. All four steroids blocked HECM-induced eosinophil survival in a dose-dependent manner. On healthy nasal mucosa methylprednisolone was the least potent (IC50 = 536 nM), deflazacort (IC50 = 264 nM) was twice as potent as methylprednisolone, while budesonide and dexamethasone were approximately nine times as potent (both IC50 = 58 nM). When potency was evaluated on the promoting effects of the HECM obtained from nasal polyps, the inhibitory potencies were lower and consequently the IC50 values were higher when compared with HECM generated from healthy nasal mucosa: methylprednisolone (IC50 = 546 nM), deflazacort (IC50 = 390 nM), dexamethasone (IC50 = 76 nM), and budesonide (IC50 = 78 nM). CONCLUSIONS: The potencies of glucocorticosteroids can be compared by evaluating their effects on the survival of eosinophils previously primed by supernatants obtained from epithelial cell culture. The different effects of steroids on eosinophils primed by HECM obtained from healthy nasal mucosa compared with HECM obtained from nasal polyps suggest that polyps might represent more active tissue which is relatively resistant to treatment with corticosteroids.
Administration, Topical↗
In vitro release of arachidonic acid metabolites, glutathione peroxidase, and oxygen-free radicals from platelets of asthmatic patients with and without aspirin intolerance.
BACKGROUND: An abnormal platelet release of oxygen-free radicals has been described in acetylsalicylic acid (aspirin)-induced asthma, a finding which might suggest the existence of an intrinsic, specific platelet abnormality of arachidonic acid metabolism in these patients. The objective of this study was to evaluate platelet arachidonic acid metabolism in asthmatic patients with or without intolerance to aspirin. METHODS: Thirty subjects distributed into three groups were studied: group 1, 10 healthy subjects; group 2, 10 asthmatic patients with aspirin tolerance; and group 3, 10 aspirin-intolerant asthmatics. Platelets were isolated from blood, preincubated with 3H-arachidonic acid for 30 minutes and then incubated for 10 minutes with platelet activating factor (PAF) and aspirin. Cyclo-oxygenase (thromboxane, PGE2, PGF2 alpha, and HHT) and lipoxygenase (12-HETE) arachidonic acid metabolites were measured by high pressure liquid chromatography. Release of oxygen free radicals after incubation with PAF and aspirin was measured by chemiluminescence. Platelet levels of glutathione peroxidase (GSH-Px) were also measured using spectrophotometry. RESULTS: Platelets from aspirin-intolerant asthmatic patients produced higher quantities of arachidonic acid metabolites than the control group at baseline conditions. This increase was significant only for lipoxygenase products. No differences were found amongst the three groups in the response of arachidonic acid metabolism to PAF and aspirin. Incubation with aspirin but not with PAF caused an increase in oxygen-free radical production in aspirin-intolerant patients whereas in aspirin-tolerant patients PAF, rather than aspirin, was the more potent stimulus for oxygen-free radical production. No differences in GSH-Px levels were found amongst the three groups. CONCLUSIONS: These results suggest that the platelet lipoxygenase pathway is activated in aspirin-intolerant patients and that the production of oxygen-free radicals may differentiate aspirin-tolerant from aspirin-intolerant asthmatic subjects. Our study, however, does not support the hypothesis that an increase in lipoxygenase products may be responsible for oxygen-free radical production. Moreover, a lowered platelet GSH-Px activity does not seem to be involved in this phenomenon.
Adult↗
The effect of neutrophil protenase enzymes on the release of mucus from feline and human airway cultures.
Neutrophils may be central in the pathogenesis of several airway diseases. The effect of two neutrophil products upon mucus release from feline and human airways was examined in vitro. Neutrophil elastase (HNE) and cathepsin G (HCG) were equipotent in stimulating mucus release from feline trachea. A potential mechanism of the mucus release was studied by exposure to HNE and various inhibitors of serine proteases or eicosanoid metabolism. Coincubation with the serine protease inhibitor, chloromethylketone, completely blocked HNE-stimulated mucus release. The putative selective cyclooxygenase inhibitor, ibuprofen, did not alter HNE-stimulated mucus release. The phospholipase A2 inhibitor, bromophenacyl bromide, and various lipoxygenase inhibitors blocked HNE-stimulated mucus release by 30-40%. The effect of HNE upon mucus release from human upper and lower airways was also examined. HNE stimulated greater mucus release from human bronchi than from nasal mucosa. The cellular source of the mucus was investigated in feline trachea and human upper airway by quantitation of mucus using enzyme assays for a specific mucous cell marker (monoclonal antibody 7F-10). HNE stimulated the release of 7F-10 detectable mucus, and after coincubation with chloromethylketone this stimulation was blocked. These data demonstrate that neutrophil products may alter airway mucus secretion and that altered eicosanoid metabolism may partially mediate these effects. Additionally, the lower airways appear more responsive to HNE than upper airways.
Animals↗
Comparison of the role of nasal polyp and normal nasal mucosal epithelial cells on in vitro eosinophil survival. Mediation by GM-CSF and inhibition by dexamethasone.
Eosinophilic infiltration of the respiratory mucosa is considered an inflammatory hallmark of allergic rhinitis, bronchial asthma and nasal polyposis. However, the mechanisms involved in this infiltration have not yet been totally elucidated. The objective of this study was to investigate and compare the influence of epithelial cell secretions from both nasal polyps (NP) and normal nasal mucosa (NM) on in vitro eosinophil survival. Epithelial cells were identified by microscopy and immunohistochemistry, cultured to confluence, and human epithelial cell conditioned media (HECM) was generated from cultures. Eosinophils were isolated at high viability and purity (> 90%) from peripheral blood and incubated with HECM. HECM from both NM and NP increased eosinophil survival in a dose-dependent manner, this effect being maximal at a concentration of 25% for NM (73.4% +/- 5.5%, n = 26, P < 0.001) and of 10% for NP (74.5% +/- 8.4%, n = 18, P < 0.001). Incubation of monoclonal antibody to human GM-CSF with HECM, neutralized the induction of eosinophil survival by HECM from both NM and NP. HECM from NP contained higher concentrations of GM-CSF (111 +/- 25.4 pg/ml, n = 17) than HECM from NM (97.1 +/- 15.2 pg/ml, n = 8), without reaching statistical significance. Pre-incubation of dexamethasone with eosinophils also blocked HECM-induced eosinophil survival from both NM (10(-8)-10(-5) M; IC50 = 9.5 nM) and NP (10(-7)-10(-5) M; IC50 = 83 nM). These results suggest that: firstly eosinophil infiltration into the respiratory mucosa during allergic reaction and nasal polyposis may be modulated at least in part by GM-CSF from epithelial cells; and secondly epithelial cells from NP might have a more potent effect on inducing eosinophil infiltration of the respiratory mucosa than epithelial cells from NM. Finally, we may consider this as a reliable in vitro model to compare the role of epithelial cells from inflammatory (NP) and non-inflammatory (NM) tissue in respiratory inflammation.
Cell Survival↗
Response of the nose to exercise in healthy subjects and in patients with rhinitis and asthma.
BACKGROUND: Although the nose and the bronchi are both involved in the process of regulating respiratory heat exchange, thermal changes may precipitate airway obstruction during exercise but rarely cause nasal obstruction in patients with rhinitis. The cause of the different response of the nose and bronchial tree has hardly been investigated. This study was performed to assess the response of the nose during exercise in the presence of rhinitis, asthma, and in normal controls. METHODS: Ten healthy subjects (group 1), 15 patients with asthma and rhinitis (group 2), 10 with rhinitis only (group 3), and 11 with asthma only (group 4) were included in the study. Exercise was performed on a bicycle ergometer for six minutes, reaching a heart rate of 80% of predicted. Bronchial and nasal responses were measured by forced expiratory volume in one second (FEV1) and posterior rhinomanometry, respectively. A drop in the FEV1 of 20% or more was considered a positive exercise induced asthma challenge test. RESULTS: Heart rate and ventilation increased by a similar proportion in the four groups. The FEV1 significantly decreased in asthmatic patients (groups 2 and 4) but it did not change in healthy subjects (group 1) or in those with rhinitis (group 3). Thirteen asthmatic patients developed exercise induced asthma. Nasal patency increased with exercise by a similar proportion in all groups, and no differences were detected between those with rhinitis (groups 2 and 3) and those without (groups 1 and 4). Nasal patency had returned to basal values at 25 minutes after completion of exercise in the four groups. The nose of patients with exercise induced asthma, however, remained significantly more patent than in patients without exercise induced asthma between 10 and 30 minutes after exercise. CONCLUSIONS: These results suggest that the nose responds differently from the bronchi during exercise induced airway obstruction: whereas the bronchial tree responds by becoming narrowed, the nose becomes more patent. These findings suggest that the mechanisms regulating the response of the nose to exercise are different from those involved in the response of the bronchial tree.
Adult↗
Release of chemical mediators and inflammatory cell influx during early allergic reaction in the nose: effect of furosemide.
BACKGROUND: We evaluated the effect of furosemide on allergen-induced rhinitis in a double-blind, crossover, placebo-controlled experiment. METHODS: Fourteen patients with rhinitis who were allergic to house dust were nebulized with an intranasal dose of 20 mg of furosemide or placebo before allergen challenge with an extract of Dermatophagoides pteronyssinus (100 BU). Clinical evaluation and nasal lavages with normal saline solution were performed at baseline; after placebo-furosemide nebulization, and at 10, 30, and 60 minutes after allergen challenge. Number of sneezes and a composite symptom score were recorded to evaluate clinical response. Prostaglandin E2 (PGE2), PGD2 peptide leukotrienes and 15-hydroxy, 5,8,11,13-eicosatetraenoic acid (15-HETE) were measured by radioimmunoassay in nasal lavages. Cells were counted and classified as epithelial cells, neutrophils, eosinophils, and others. RESULTS: No differences in either clinical symptoms or cell influx after allergen challenge were found between furosemide and placebo groups. PGE2 levels did not change after provocation, and furosemide had no effect on its production. Ten minutes after antigen challenge there was a marked increase of PGD2 (p < 0.01), peptide leukotrienes (p < 0.01), and 15-HETE (not significant) on both study days. However, no significant differences in the release of eicosanoids were found between furosemide and placebo groups. CONCLUSIONS: Our observations in the nasal mucosa suggest that furosemide has no effect on the release of proinflammatory and bronchoconstrictor metabolites (PGD2, peptide leukotrienes, and 15-HETE). In contrast to bronchial asthma, allergen-induced rhinitis was not effectively prevented by furosemide.
Adult↗
Immunocytologic analysis of nasal cells obtained by nasal lavage: a comparative study with a standard method of cell identification.
For evaluation of two methods of nasal cell identification, cell morphology and immunocytologic analysis, nasal lavage was performed in 16 healthy subjects and 29 patients suffering from rhinitis. Nasal lavage smears were stained with May-Grünwald-Giemsa (MGG), and cells were identified according to their structure as epithelial cells, neutrophils, lymphocytes, eosinophils, and metachromatic cells (basophils and mast cells). Immunocytologic analysis was performed with monoclonal antibodies by the immunoalkaline phosphatase method. The following monoclonal antibodies were used: CK1, EG2, and CD3, which identify epithelial cells, activated eosinophils, and T lymphocytes, respectively; CD15, which recognizes mature granulocytic cells; and CD14, which reacts with monocytes and macrophages. A significant difference was observed between the two methods in the number of identified epithelial cells, in both controls (64.6 +/- 7.8% with MGG, 14.2 +/- 3.5% with CK1 analysis) and patients with rhinitis (56.9 +/- 7.6% with MGG, 18.2 +/- 3.7% with CK1 analysis). In contrast, no significant differences were found in eosinophil and neutrophil counts when the two methods were compared. After nasal allergic provocation, a significant increase in the number of eosinophils was observed with both methods in seven patients with rhinitis. The results of this study indicate that: 1) MGG staining is a useful method to identify the cells obtained by nasal lavage, and 2) immunocytologic analysis with monoclonal antibodies accurately identifies granulocytic cells, while only a low proportion of epithelial cells are detected, probably because anticytokeratin monoclonal antibody reacts only with viable cells.
Adult↗
Failure of frusemide to increase production of prostaglandin E2 in human nasal mucosa in vivo.
BACKGROUND: It has been suggested that inhaled frusemide protects subjects with asthma against bronchoconstriction by enhancing the synthesis of prostaglandin E2 (PGE2). To evaluate this hypothesis the effect of frusemide on PGE2 production from nasal mucosa was studied. METHODS: Two main arachidonic acid metabolites produced by epithelial cells, PGE2 and 15-hydroxy 5,8,11,13-eicosatetraenoic acid (15-HETE), were measured by radioimmunoassay in nasal secretions obtained by nasal lavages with saline. Eleven healthy volunteers were randomly assigned to two study days, one week apart, in a double blind crossover study. Nasal instillation with three increasing doses of frusemide (5, 10, and 20 mg) or placebo was carried out at intervals of 15 minutes. Nasal lavages were performed immediately before nasal instillations and 15, 30, and 60 minutes after the last instillation. RESULTS: Baseline concentrations of 15-HETE were at least six times higher than PGE2. No differences between frusemide and placebo were detected either on PGE2 or 15-HETE release. CONCLUSIONS: The findings do not support the hypothesis that the antiasthmatic effect of frusemide may be due to increased synthesis of PGE2 or release in the respiratory mucosa.
Adult↗
Muscarinic receptor subtypes in human nasal mucosa: characterization, autoradiographic localization, and function in vitro.
Muscarinic receptors play important roles in the regulation of glandular secretion and vasomotor tone in human nasal mucosa. M1, M2, and M3 muscarinic receptor subtypes were pharmacologically characterized in human inferior turbinates by receptor-binding assays using [3H](-)quinuclidinyl benzilate (QNB, identifies total muscarinic receptors) and [3H]-pirenzepine (PZ). Receptors were localized by autoradiography, and their function examined in vitro by assaying mucus secretion from cultured nasal mucosal explants. In competition assays, PZ was employed as a selective muscarinic antagonist for M1 receptors, gallamine and AF-DX 116 for M2 receptors, and 4-DAMP for M3 receptors. These ligands are selective at low nanomolar concentrations, but can interact with other muscarinic receptors at higher concentrations. It is not known if they can interact with putative M4 and M5 muscarinic receptor subtypes. Using [3H](-)QNB, total muscarinic receptor binding was 688.4 +/- 49.6 fmol/mg protein (Bmax), with a Kd of 1.47 +/- 0.13 nM. [3H]-PZ bound to 45% of the total QNB binding sites. In competition experiments, 4-DAMP displaced [3H](-)QNB with the lowest IC50, followed by PZ and AF-DX 116. Autoradiograms demonstrated that [3H](-)QNB binding was completely displaced by 4-DAMP, partially displaced by PZ, but not displaced by gallamine or AF-DX 116, and suggested that M1 and M3 subtypes coexist in submucosal glands. The localization of M1 receptors on submucosal glands was confirmed by direct labeling with [3H]-PZ. [3H]-PZ also labeled vessels, but with a low silver grain density. Autoradiographic [3H]-QNB binding was displaced by 4-DAMP and atropine, but not by PZ, gallamine, or AF-DX 116. In studies of mucus secretion in vitro, 4-DAMP significantly inhibited methacholine-induced secretion. Although less effective, PZ also had significant inhibitory effects. Neither gallamine nor AF-DX 116 had any inhibitory effect. M1 receptors (PZ binding sites) may regulate glandular secretion while M3 receptors (4-DAMP binding sites) may regulate glandular secretion and vasomotor tone in human nasal mucosa.
Autoradiography↗
Endothelin in human nasal mucosa.
Endothelin (ET), a potent vasoconstrictor and bronchoconstrictor peptide synthesized by endothelial and epithelial cells, was examined for its potential functions in human inferior turbinate nasal mucosal tissue by four techniques: (1) immunoreactive ET was localized in the mucosa by immunohistochemistry; (2) receptors for ET were identified by autoradiography employing [125I]ET; (3) ET-1 mRNA was localized by in situ hybridization; and (4) the secretory functions of ET were examined by the release of mucous and serous cell products after the addition of ET to human nasal turbinates in short-term cultures. Specific ET-1-immunoreactive material was found most extensively in small muscular arteries and in serous cells in submucosal glands. ET-1 was also found to a lower extent in the walls of venous sinusoids. [125I]ET-1 binding sites were localized by autoradiography to submucosal glands and to venous sinusoids and small muscular arterioles. mRNA for ET-1 was found most extensively in the venous sinusoids and to a lesser extent in small muscular arteries. In mucosal explant cultures, ET-1 and ET-2 stimulated lactoferrin and mucous glycoprotein release from serous and mucous cells, but ET-3 was inactive. The observations indicate that in the human nasal mucosa, ET is present in the vascular endothelium and the serous cells in submucosal glands and acts on glandular ET receptors to induce both serous and mucous cell secretion. It is also likely that ET plays a role in the regulation of vasomotor tone.
Binding Sites↗
Cell content and albumin concentration in nasal lavage from patients with rhinitis.
Influx of inflammatory cells in the nose was evaluated in 14 patients with rhinitis and 11 healthy subjects. Nasal secretions were obtained by nasal lavages. Total cell count and differential count were carried out with a Neubauer chamber and in cytospin slides, respectively. Cells were classified according to their morphology as epithelial cells without nuclei (degenerated), epithelial nucleated cells, neutrophils, eosinophils, and other. Total protein and albumin concentration were measured by the Lowry method and a nephelometric assay respectively. A statistically significant difference was found in total nucleated epithelial cells (P < .01), total neutrophils (P < .01), and total eosinophils (P < .05) between patients and healthy subjects. A significant correlation was found between albumin/total protein concentration with eosinophil numbers (r = .83, P < .001) in patients with rhinitis. These findings suggest that eosinophils participate in the inflammatory process taking place in rhinitis. Since the cellularity present in the nose of rhinitic patients is similar to that usually found in the bronchial secretions of asthmatic patients obtained by bronchoalveolar lavage, our results also suggest that nasal lavage may be used in the study of the inflammatory cells involved in airway diseases.
Adult↗
The effect of IL-4 on human nasal mucosal responses.
Interleukin (IL)-4 causes the dose limiting sensation of nasal congestion when administered systematically at doses of 3 micrograms/kg or higher thrice daily to humans. This side effect was observed in a group of patients treated as part of an immunotherapy protocol for cancer management. To determine the source of this congestion, nasal secretions were collected prospectively in a group of patients at baseline and after provocation with normal saline, methacholine (which stimulates glandular secretion), and histamine (which causes increased vascular permeability). Nasal lavages obtained at baseline and after provocation were analyzed for the presence of these glandular and vascular proteins and inflammatory mediators. Washings and provocations were performed before IL-4 administration, after 24 hours of IL-4 treatment, and after 3 days of treatment, at a time when nasal congestion was maximal. Compared with histamine challenge before IL-4 treatment, the secretion of the plasma proteins albumin and IgG were significantly decreased after 3 days of IL-4 treatment. IL-4 treatment had no apparent effect on methacholine-induced responses. Thus systemically administered IL-4 causes the subjective sensation of nasal congestion, increased histamine in nasal lavages, and the development of vascular unresponsiveness to histamine, without affecting parasympathetic responses to histamine. The relationships among increases in nasal lavage histamine, vascular unresponsiveness to histamine, and the sensation of nasal congestion are unclear.
Adult↗
Comparison of human nasal mucosal secretion in vivo and in vitro.
The secretion of proteins from the human nasal mucosa induced by histamine, alpha-adrenergic, beta-adrenergic, and cholinergic agonists was studied in vivo and in vitro. Glandular secretion of lactoferrin, lysozyme (in vivo only), and respiratory glycoconjugates (RGCs) was measured. Vascular permeability was determined in vivo by albumin secretion in relationship to the other proteins. Muscarinic stimulation by methacholine induced significant glandular secretion (lactoferrin, lysozyme and/or RCGs) both in vivo and in vitro, confirming that muscarinic receptors are stimulated directly. Histamine induced predominantly vascular permeability in vivo but caused some glandular secretion as well. However, in vitro, histamine had no effect on glandular secretion, suggesting that histamine acts predominantly on the nasal vascular bed and only affects glandular secretion through reflex actions. Phenylephrine, an alpha-adrenergic agonist, selectively stimulated lysozyme release in vivo, and both RGCs and lactoferrin release in vitro. Thus, alpha-adrenergic stimulation has some direct, albeit minimal, capacity to stimulate mucosal glands. beta-Adrenergic agonists had no effect on glandular secretion or vascular permeability either in vivo or in vitro. Therefore, glandular secretion is directly stimulated by alpha-adrenergic and cholinergic agonists, but not by beta-adrenergic agonists. The stimulation of glandular secretion by histamine is indirect and mediated through the action of neural reflexes.
Adult↗
Effects of nedocromil sodium on allergen-induced rhinitis in humans.
Sixteen patients with allergic rhinitis were recruited into a double-blind crossover protocol studying the immediate effect of nedocromil sodium (NS) on the pattern of nasal symptoms and secretions after allergen challenge. After pretreatment with placebo or NS, allergen challenge resulted in pruritus, rhinorrhea, nasal congestion, and/or sneezing within 10 minutes in 12 of 16 subjects. Prostaglandin D2 (PGD2), a marker of mast cell degranulation, increased proportionately with symptom scores, remaining above the 95% confidence interval for 120 minutes after both pretreatments. No difference in PGD2 between the NS-treatment and placebo-treatment days was observed. Protein markers extravasated through the vasculature (albumin and IgG) or secreted by mucosal glands (lactoferrin) were assayed. Total protein, albumin, IgG, and lactoferrin all remained greater than 95% confidence interval for 100 minutes after allergen challenge in the placebo-pretreated group and 120 minutes in the NS-pretreated group. Although there appeared to be a trend for lower secretion of PGD2, albumin, and IgG in the NS-treated group, the overall differences did not achieve statistical significance. This protocol revealed that two topical 130 microliter doses of a 1% solution of NS failed to significantly reduce allergen-induced symptoms, PGD2 generation, or secretion of albumin, IgG, or lactoferrin when NS was compared with placebo. The anti-inflammatory and mast cell-stabilizing effects of NS may require more prolonged pretreatment before provocation to be effective.
Adult↗
The effects of neuropeptides on mucous glycoprotein secretion from human nasal mucosa in vitro.
The role of neuropeptides in the regulation of macromolecule secretion from human nasal mucosa is incompletely understood. Previous in vitro explant culture studies have demonstrated the effects of neuropeptides on lactoferrin release from serous cells and 3H-glucosamine labeled respiratory glycoconjugate secretion from mucus-containing cells. The generation of a new monoclonal antibody, 7F10, has led to the development of an ELISA for high molecular weight respiratory mucous glycoproteins (MGP). This ELISA was used to measure the ability of sensory, parasympathetic and sympathetic neuropeptides to stimulate MGP release from human nasal mucosal fragments in short term explant culture in vitro. Significant MGP release was stimulated by the sensory neuropeptides gastrin releasing peptide (10 microM GRP: 10.6% +/- 2.4% increase, n = 8, P less than 0.01 vs. control), substance P (1 microM SP: 12.5% +/- 5.4%, n = 11, P less than 0.05), neurokinin A (1 microM NKA: 17.8 +/- 4.3%, n = 6, P less than 0.01), while calcitonin gene related peptide (CGRP) was without effect. Vasoactive intestinal peptide (VIP), a neurotransmitter from parasympathetic nerves, induced significant dose dependent MGP secretion, but had no additive or inhibitory interaction with methacholine-induced secretion. Neuropeptide Y (NPY), present in sympathetic nerves, had no effect on MGP secretion. These observations correlate with the effects of neuropeptides on serous cell lactoferrin secretion, and the presence of specific GRP, SP, and VIP binding sites on human nasal submucosal glands that have been detected by autoradiography. GRP and tachykinins (SP and NKA) from sensory nerves, and VIP released during parasympathetic reflexes may significantly stimulate mucous and serous cell secretion from human nasal mucosa in vivo.
Calcitonin Gene-Related Peptide↗
M1 and M3 muscarinic antagonists inhibit human nasal glandular secretion in vitro.
Mucus glycoproteins (MGP) are high-molecular-weight glycoconjugates that are released from submucosal glands and epithelial goblet cells in the respiratory tract. Muscarinic receptors have an important role in the regulation of human nasal glandular secretion and mucus production, but it is not known which of the five muscarinic receptor subtypes are involved. The effect of nonselective and M1-, M2-, and M3-selective muscarinic antagonists on methacholine (MCh)-induced MGP secretion from human nasal mucosal explants was tested in vitro. MGP was assayed by enzyme-linked immunosorbent assay using a specific anti-MGP monoclonal antibody (7F10). MCh (100 microM) induced MGP secretion up to 127% compared with controls. MCh-induced MGP release was significantly inhibited by atropine (100 microM), the M, receptor antagonist pirenzepine (10-100 microM), and the M3 receptor antagonist 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP; 1-100 microM). 4-DAMP significantly inhibited MCh-induced MGP release at a lower concentration (1 microM) than pirenzepine (10 microM). The M2 receptor antagonists AF-DX 116 and gallamine (both at 100 microM) had no effect. No antagonist alone had a significant effect on MGP release. These results indicate that the M1 and M3 muscarinic receptor subtypes regulate MGP secretion from human nasal mucosa and suggest that the M3 receptor has the predominant effect.
Antibodies, Monoclonal↗