Cytokine gene expression and release from epithelial cells. A comparison study between healthy nasal mucosa and nasal polyps

Cytokine Signature and Involvement in Chronic Rhinosinusitis with Nasal Polyps

Cytokines are well known to play a central role in chronic rhinosinusitis with nasal polyps (CRSwNP), particularly in maintenance of the inflammatory response and the recruitment of eosinophils. The pathophysiological concepts concerning the involvement of inflammatory cytokines in CRSwNP have gradually evolved. Although the Th2 cytokines environment associated with an eosinophilic infiltration has retained a central role in the genesis of polyps, the role of other cytokine subpopulations has also and more recently been detailed, leading to a specific and complex signature in CRSwNP. The purpose of this review is to summarize the current state of knowledge about the cytokine signature in CRSwNP, the role of cytokines in the pathogenesis of this disease and in the intercellular dialog between epithelial cells, fibroblasts and inflammatory cells. Knowledge of this precise cytokine signature in CRSwNP is fundamental in the perspective of potential targeting biotherapies.

A novel nasal co-loaded loratadine and sulpiride nanoemulsion with improved downregulation of TNF-α, TGF-β and IL-1 in rabbit models of ovalbumin-induced allergic rhinitis

PURPOSE

The work aimed to develop a co-loaded loratadine and sulpiride nasal nanoemulsion for allergic rhinitis management.

METHODS

Compatibility studies were conducted adopting differential scanning calorimetry and Fourier transform infrared spectroscopy. Nanoemulsion formulations were prepared using soybean lecithin, olive oil and tween 80. Sodium cholate and glycerol were employed as co-surfactants. Nanoemulsions were assessed for viscosity, pH, droplet size, polydispersity index, zeta potential, electrical conductivity, entrapment, In vitro drug release and corresponding kinetics. Stability of the selected formulation was investigated. The biological effectiveness was evaluated in rabbit models of ovalbumin-induced allergic rhinitis by measuring TNF-α, TGF-β and IL-1.

RESULTS

Compatibility studies revealed absence of drug/drug interactions. Nanoemulsions exhibited > 90% entrapment efficiency. The selected nanoemulsion demonstrated small droplet size (85.2 ± 0.2 nm), low PDI (0.35 ± 0.0) and appropriate Zeta Potential (-23.3 ± 0.2) and stability. It also displayed enhanced in vitro drug release following the Higuashi Diffusion and Baker-Lonsdale models. The mean relative mRNA expression of TNF-α, IL-1 and TGF-β significantly decreased from 9.59 ± 1.06, 4.15 ± 0.02 and 4.15 ± 0.02 to 1.28 ± 0.02, 1.93 ± 0.06 and 1.56 ± 0.02 respectively after treatment with the selected nanoemulsion formulation.

CONCLUSION

The results reflected a promising potent effect of the combined loratadine and sulpiride nasal nanoemulsion in managing the symptoms of allergic rhinitis.

The possibility of short-term hypothalamic-pituitary-adrenal axis suppression with high-volume, high-dose nasal mometasone irrigation in postsurgical patients with chronic rhinosinusitis

BACKGROUND

Medically refractory chronic rhinosinusitis (CRS) is often treated with functional endoscopic sinus surgery (FESS) and high-volume steroid nasal irrigation. While budesonide is the most common steroid irrigation for this indication, mometasone has a superior pharmacokinetic profile, which may allow dose escalation. The safety and efficacy of mometasone at higher concentrations than previously used in treating CRS have not been explored.

METHODS

Patients were recruited from a tertiary level clinic between June 2018 and December 2019. Inclusion criteria included adults (>18 years); CRS diagnosis; previous FESS; pre-treatment morning cortisol within normal range; minimum of twice daily high-volume sinonasal mometasone irrigations (total dose of 4 mg) for 12 weeks; and post-treatment morning cortisol measured within 2 weeks following the study period. Patients with potential for endogenous or exogenous disruption of the HPA axis were excluded.

RESULTS

14 patients were enrolled in this prospective cohort study. In all but one patient, pre- and post-treatment morning cortisol levels were not significantly different and were within normal limits (6.7-25.4 μg/dL). Following an uninterrupted 12-week treatment course, no evidence of HPA axis suppression was found (P = 0.915). The single patient who was found to have a low (1.3 μg/dL) post-treatment morning serum cortisol level reportedly received an intraarticular steroid shot several days prior to the blood draw. She remained asymptomatic and her rechecked serum cortisol was within normal limits at 12.3 μg/dL.

CONCLUSIONS

High-volume 2 mg twice daily sinonasal mometasone irrigations did not cause HPA axis suppression in a representative sample of patients with refractory CRS post-FESS with normal baseline cortisol levels.

Key role of the epithelium in chronic upper airways diseases

The respiratory epithelium of the upper airways is a first-line defence against inhaled irritants, pathogens and allergens. It ensures a physical barrier provided by apical junctions and mucociliary clearance to avoid excessive activation of the immune system. The epithelium also forms a chemical and immunological barrier, extensively equipped to protect the airways against external aggressions before the adaptive immune system is required. Under normal circumstances, the epithelium is capable of recovering rapidly after damage. This manuscript reviews these main properties of the upper airway epithelium as well as its reported impairments in chronic inflammatory diseases. The knowledge on normal epithelial functions and their dysregulation in upper airway diseases should help to design new epithelial-targeted treatments.

Contribution of Epithelial Cell Dysfunction to the Pathogenesis of Chronic Rhinosinusitis with Nasal Polyps

Background

In the past, the airway epithelium was thought to be primarily an inert physical barrier. We now know that the upper airway epithelium plays a critical role in both innate and adaptive immunity, and that epithelial dysfunction is strongly associated with inflammatory airway disease. The pathogenesis of chronic rhinosinusitis is poorly understood, but growing evidence supports a key role for the airway epithelium in the pathophysiology of the disease.

Objective

The purpose of this study is to explore our current understanding of how dysfunction in human sinonasal epithelial cells (HSNECs) contributes to the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP) and to examine how current and developing therapies affect epithelial cell functions.

Methods

A literature review of papers published in English pertaining to epithelial cell dysfunction in patients with CRSwNP was performed using the PubMed database. The search utilized combinations of the following key words: sinusitis, polyps, epithelium, pathophysiology, barrier function, dendritic cells, eosinophils, T cells, complement, mucociliary clearance, vitamin D, cytokines, chemokines, taste receptors, steroids, saline, and therapy.

Results

HSNEC mucociliary clearance, barrier function, secretion of cytokines, influence on dendritic cells, influence on T-cells, regulation of eosinophils, vitamin D metabolism, complement production, and taste receptor function are altered in patients with CRSwNP and contribute to the pathogenesis of the disease. Current therapies utilized to manage CRSwNP counteract the effects of HSNEC dysfunction and relieve key symptoms of the disease.

Conclusion

HSNECs are key players in both innate and adaptive immunity, and altered epithelial functions are closely intertwined with the pathogenesis of CRSwNP. Our review supports further investigation of altered HSNEC function in patients with CRSwNP and supports development of novel epithelial-targeted therapies for its management.

Superior effect of MP-AzeFlu than azelastine or fluticasone propionate alone on reducing inflammatory markers

BACKGROUND

MP-AzeFlu, intranasal formulation of azelastine hydrochloride (AZE) and fluticasone propionate (FP), is superior to AZE or FP alone for treatment of allergic rhinitis (AR). However, the precise anti-inflammatory mechanism of action of MP-AzeFlu has not been characterized.

OBJECTIVE

To investigate the anti-inflammatory effects of MP-AzeFlu compared with AZE or FP alone in an established in vitro model of eosinophilic inflammation.

METHODS

Nasal mucosal epithelial cells and peripheral blood eosinophils were obtained from human volunteers. Epithelial cells were stimulated with 10% fetal bovine serum (FBS) in the presence of MP-AzeFlu, AZE, or FP (1:102 to 1:105 dilution). Concentrations of interleukin (IL)-6, IL-8, and granulocyte-macrophage colony-stimulating factor (GM-CSF) were measured by ELISA. Eosinophils were incubated in 10% human epithelial cell-conditioned medium (HECM) and survival assessed by trypan blue dye exclusion. Results are expressed as mean ± SEM percentage secretion/survival compared with FBS/HECM (respectively).

RESULTS

FP and MP-AzeFlu (all dilutions) and AZE (1:102) significantly reduced IL-6 secretion and eosinophil survival compared with positive controls. At 1:102 dilution, IL-6 secretion was significantly lower with MP-AzeFlu (38.3 ± 4.2%, compared with FBS = 100%) than with AZE (76.1 ± 4.9%) or FP (53.0 ± 4.9%). At 1:102 dilution, eosinophil survival was significantly lower with MP-AzeFlu at day 3 (17.5 ± 3.0%) and day 4 (2.4 ± 1.4%, compared with HECM = 100%) than with AZE (day 3: 75.2 ± 7.2%; day 4: 44.0 ± 9.7%) or FP (day 3: 38.5 ± 3.5%; day 4: 14.6 ± 4.0%).

CONCLUSION

Greater reductions in cytokine secretion and eosinophil survival observed with MP-AzeFlu in vitro may underlie MP-AzeFlu's superior clinical efficacy vs. AZE or FP alone observed in AR patients.

Radiofrequency-Induced Thermotherapy on Nasal Polyps: Preliminary Results

Background

The aim of this study was to determine the effects of radiofrequency-induced thermotherapy (RFITT) in patients with nasal polyps.

Methods

A retrospective analysis was performed of prospectively collected data from 17 consecutive patients (11 men and 6 women; mean age, 51.7 ± 16.9 years) treated with RFITT from 2002 to 2003. The postoperative outcome was assessed using active anterior rhinomanometry, “sniffin’ stick” test, and endoscopic nasal examination preoperatively and 4 weeks postoperatively. Subjective complaints were assessed with Likert scales.

Results

Transnasal airflow increased by 40.3% 4 weeks postoperatively (p = 0.029). Endoscopic appearance of nasal polyps indicated a nonsignificant reduction of 37.1%. Subjective complaints such as impaired nasal ventilation (p = 0.014), nasal discharge (p = 0.0007), postnasal drip (p = 0.0002), and hyposmia (p = 0.048) improved significantly 4 weeks after surgery.

Conclusion

RFITT is well tolerated as a day case procedure under local anesthesia and might be a procedure for treating recurrence of NP after sinus surgery. It remains unclear at this point whether RFITT for nasal polyps results in a permanent reduction.

Activation of Activin receptor-like kinases curbs mucosal inflammation and proliferation in chronic rhinosinusitis with nasal polyps

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a widespread disease causing obstruction of the nasal cavity. Its cause remains unclear. The transforming growth-factor beta (TGF-β) superfamily and their receptors, termed Activin receptor-like kinases (ALKs), have recently been suggested to play a role in local airway inflammation, but have so far not been evaluated in human nasal epithelial cells (HNECs) from CRSwNP patients. We demonstrated that ALK1–7 were expressed in the nasal polyp epithelium, and the expression of ALK1-6 was markedly elevated in polyps compared to nasal mucosa from healthy controls. Stimulation with the ALK ligand TGF-β1 decreased Ki67 expression in HNECs from CRSwNP patients, not evident in controls. Likewise, TGF-β1, Activin A and Activin B, all ALK ligands, decreased IL-8 release and Activin A and Activin B reduced ICAM1 expression on HNECs from CRSwNP patients, not seen in controls. Pre-stimulation with TGF-β1, Activin A, BMP4 and Activin B attenuated a TNF-α-induced ICAM1 upregulation on HNECs of CRSwNP. No effect was evident in controls. In conclusion, an increased expression of ALK1-6 was found on polyp epithelial cells and ligand stimulation appeared to reduce proliferation and local inflammation in polyps.

C-C Chemokine Ligand 2 Gene Expression in Nasal Polyp Fibroblasts: Possible Implication in the Pathogenesis of Nasal Polyposis

Objectives:

Recruitment of macrophages is essential to the pathogenesis of nasal polyps (NP), since this disease is inflammation-related. In this study, the effects of tumor necrosis factor α (TNF-α) on the expression of C-C chemokine ligand 2 (CCL2) in fibroblasts derived from nasal polyps (NPFs) were investigated. The roles of cyclooxygenase (COX) 2 and prostaglandins in the mediation of TNF-α–stimulated CCL2 gene expression were also investigated.

Methods:

Northern blot analysis was used to study the expression of CCL2 and c-Fos in cultured NPFs. An electrophoretic mobility shift assay was used to explore the interactions between activator protein 1 (AP-1) and DNA. Immunohistochemistry was used to explore the in vivo expressions of COX-2, CCL2, and CD68 in NPs.

Results:

The Northern blot analysis showed that TNF-α stimulated the expression of CCL2 and COX-2 genes, and the synthesis of CCL2 messenger RNA was COX-2-dependent. A transient elevation of c-Fos and c-Jun messenger RNAs was induced by TNF-α, whereas COX-2 inhibitors NS-398 and meloxicam abolished the up-regulation of c-Fos. The electrophoretic mobility shift assay revealed that TNF-α triggered AP-1 and DNA binding and again, NS-398 and meloxicam inhibited this reaction via reducing c-Fos synthesis. Curcumin (AP-1 inhibitor) markedly suppressed the TNF-α–induced CCL2 expression. The immunohistochemical staining of NP surgical specimens also revealed an intimate alignment between CCL2-positive fibroblasts and CD-68-positive macrophages.

Conclusions:

These data suggest that NPFs may contribute to NP development by synthesizing CCL2 to promote macrophage recruitment. Furthermore, COX-2 facilitates CCL2 transcription in NPFs via a c-Fos and AP-1 signaling pathway.

Pathogenesis of nasal polyposis

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a complex inflammatory condition that affects a large proportion of the population world-wide and is associated with high cost of management and significant morbidity. Yet, there is a lack of population-based epidemiologic studies using current definitions of CRSwNP, and the mechanisms that drive pathogenesis in this disease remain unclear. In this review, we summarize the current evidence for the plethora of factors that likely contribute to CRSwNP pathogenesis. Defects in the innate function of the airway epithelial barrier, including diminished expression of antimicrobial products and loss of barrier integrity, combined with colonization by fungi and bacteria likely play a critical role in the development of chronic inflammation in CRSwNP. This chronic inflammation is characterized by elevated expression of many key inflammatory cytokines and chemokines, including IL-5, thymic stromal lymphopoietin and CCL11, that help to initiate and perpetuate this chronic inflammatory response. Together, these factors likely combine to drive the influx of a variety of immune cells, including eosinophils, mast cells, group 2 innate lymphoid cells and lymphocytes, which participate in the chronic inflammatory response within the nasal polyps. Importantly, however, future studies are needed to demonstrate the necessity and sufficiency of these potential drivers of disease in CRSwNP. In addition to the development of new tools and models to aid mechanistic studies, the field of CRSwNP research also needs the type of robust epidemiologic data that has served the asthma community so well. Given the high prevalence, costs and morbidity, there is a great need for continued research into CRS that could facilitate the development of novel therapeutic strategies to improve treatment for patients who suffer from this disease.

Nasal lavage levels of granulocyte-macrophage colony-stimulating factor and chronic nasal hypereosinophilia

BACKGROUND

The aim of the present study was to measure levels of granulocyte-macrophage colony-stimulating factor (GM-CSF) in nasal lavage of patients affected by chronic eosinophilic sinonasal inflammation to clarify the relationship with eosinophilic tissue infiltration and clinical features.

METHODS

Between November 2012 and June 2013, we selected 70 patients with chronic eosinophilic inflammation (average age 41.8 years) who were classified into the following groups: persistent allergic rhinitis (group 1), noninfectious non-allergic rhinitis with eosinophilia syndrome (group 2) and chronic rhinosinusitis with polyps (group 3). Finally, we enrolled 20 healthy subjects as controls (group 4). All patients underwent symptoms score questionnaire based on a visual analogue scale, nasal endoscopy and/or computed tomography (CT) scan, and allergy testing. Nasal cytology by scraping of the mucosa and GM-CSF assays in nasal lavage were performed in all subjects.

RESULTS

Detectable levels of GM-CSF were found in 34 of 70 (48.57%) patients, with an average concentration of 2.67 ± 0.8 pg/mL, whereas in controls only 1 of 20 individuals showed detectable GM-CSF levels. Eosinophil infiltration was significantly higher in patients with detectable GM-CSF compared to those with undetectable levels (49.4% vs 39.2%, respectively; p < 0.05). Furthermore, significant weakly-moderate correlation was found between GM-CSF levels and percentage of eosinophil infiltration in tissue (p < 0.05). Correlation between symptom scores and GM-CSF levels was significant only in group 2, which showed higher average concentrations of GM-CSF compared to groups 1 and 3 (2.9 pg/mL vs 1.6 pg/mL and 1.8 pg/mL, respectively; p < 0.05).

CONCLUSION

Our data confirm that GM-CSF is more frequently detectable in nasal lavages of patients affected by chronic sinonasal eosinophilic inflammation than in controls. Statistical analyses revealed a significant weakly-moderate correlation between GM-CSF levels in nasal lavage of all patients and percentage of eosinophil infiltration of nasal mucosa.

Fluticasone furoate inhibits cytokine secretion from nasal epithelial cells and reduces eosinophil survival in an in vitro model of eosinophilic inflammation

BACKGROUND

Fluticasone furoate (FF) is an intranasal corticosteroid indicated for the treatment of allergic rhinitis (AR). However, the anti-inflammatory effects of FF in the nasal mucosa have yet to be investigated thoroughly. The aim of this study was to investigate the effect of FF on eosinophil survival and cytokine secretion from nasal mucosa epithelial cells.

METHODS

Epithelial cells obtained from nasal mucosa were stimulated with 10% fetal bovine serum (FBS) in the presence of FF (from 10(-12) to 10(-7)M) for 6-24 h. Cytokine [granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-6 and IL-8] concentrations in supernatants were measured by ELISA. Peripheral blood eosinophils were incubated for 4 days with epithelial cell secretions in the presence or absence of FF (from 10(-12) to 10(-7)M) and survival was assessed by Trypan blue dye exclusion. Results are expressed as medians of the minimum effective concentration and IC values.

RESULTS

FBS stimulated the secretion of GM-CSF, IL-6 and IL-8. FF significantly inhibited GM-CSF (up to 10(-10)M, IC25 = 12.6 pM), IL-6 (up to 10(-10)M, IC25 = 65.8 pM) and IL-8 (up to 10(-11)M, IC25 = 8.6 pM) secretion induced by FBS (n = 8). Epithelial cell secretions induced eosinophil survival from day 1 to day 4 (n = 6). This effect was significantly inhibited by FF (up to 10(-12)M) at day 3 (IC50 = 3.22 nM) and day 4 (IC50 = 1.29 nM).

CONCLUSIONS

The results obtained in this in vitro model suggest that FF may reduce upper airway eosinophilic inflammation through decreasing cytokine secretion from epithelial cells and reducing eosinophil survival.

Effects of fungi and eosinophils on mucin gene expression in rhinovirus-infected nasal epithelial cells

Purpose

Fungi, rhinoviruses (RVs), and eosinophils are associated with upper respiratory diseases. We evaluated the effects of fungal stimulation and eosinophil co-culture on the expression of mucin genes in RV-infected nasal polyp epithelial cells.

Methods

Nasal polyp epithelial cells were obtained from chronic rhinosinusitis patients. Cultured epithelial cells were stimulated with Alternaria and Aspergillus with or without RV-16 infection. The epithelial cells were co-cultured with eosinophils for 16 h. MUC4, MUC5AC, MUC5B, and MUC8 mRNA expressions in the epithelial cells were quantified using real-time RT-PCR. To determine the underlying mechanism, nuclear factor-κB (NF-κB), activator protein-1 (AP-1), and mitogen-activated protein kinase (MAPK) inhibitors were used to inhibit mucin gene expression.

Results

Fungi and RV-16 induced mucin gene expression in nasal polyp epithelial cells. However, there was no synergistic increase in mucin gene expression, with the exception of MUC4 mRNA expression stimulated by 25 µg/mL Aspergillus. When RV-16-infected epithelial cells were stimulated with fungi and then co-cultured with eosinophils, MUC4, MUC5B, and MUC8 mRNA expressions increased. Mucin gene expression was inhibited by NF-κB inhibitors.

Conclusions

RV-16, airborne fungi, and eosinophils may exacerbate the inflammatory process in nasal mucosal diseases by enhancing mucin gene expression.

Chronic rhinosinusitis and emerging treatment options

This review describes the epidemiology and various treatments in chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP). Evidence for short-term use of systemic corticosteroids has been shown to be favorable in CRSwNP, but still limited in CRSsNP. Topical corticosteroids improve symptom scores in both CRS subgroups. The role of microbes in CRS is still controversial. Culture-directed antibiotics are recommended for CRSsNP with exacerbation. Long-term use of low dosage antibiotics is recommended for CRSsNP for their anti-inflammatory effects. Other emerging treatment options are also discussed.

Update on the management of chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a common disorder characterized by mucosal inflammation of the nose and paranasal sinuses with sinonasal symptoms persisting for greater than 12 weeks. The etiology of CRS is incompletely understood. Current understanding supports inflammation, rather than infection, as the dominant etiologic factor. CRS significantly impacts patients' quality of life and health care expenditure. There is no standard management of CRS. Treatment strategies differ based on divergent etiologies of the various CRS subclasses. Both systemic and topical agents are used. These interventions differ in CRS with nasal polyposis (CRSwNP), CRS without nasal polyposis (CRSsNP) and specific situations such as allergic fungal rhinosinusitis or aspirin-exacerbated respiratory disease. Antibiotics are the most commonly prescribed medication for CRS, but their role in management is not strongly supported by high-level studies. This paper provides a succinct review of the evidence supporting or refuting common therapeutic agents in the management of CRS. Novel and emerging strategies will also be discussed.

Effects of Asian sand dust on mucin gene expression and activation of nasal polyp epithelial cells

BACKGROUND

Asian sand dust (ASD) contains a variety of chemical and microbiological materials such as lipopolysaccharide (LPS) and beta-glucan that can cause inflammation. The increase in the atmospheric concentration of ASD has been associated with asthma severity and adverse effects on respiratory function. The aim of this study was to evaluate the effect of ASD on the inflammatory process and mucin gene expression in nasal epithelial cells.

METHODS

Primary nasal polyp epithelial cells were exposed to ASD for 72 hours, and then the supernatants were collected. To determine the activation of the epithelial cells, IL-6, IL-8, and granulocyte-macrophage colony-stimulating factor were measured. In addition, the potential cytotoxic effects of ASD on the epithelial cells were evaluated. Quantitative reverse-transcription polymerase chain reaction for MUC4, MUC5AC, MUC5B, and MUC8 mRNA expression, in the nasal epithelial cells, was performed.

RESULTS

ASD stimulated the production of chemical mediators in a time-dependent manner. The cytokine production was highest at 100 micrograms/mL of ASD. MUC4 and MUC5B mRNA expression was significantly increased at 10 and 50 micrograms/mL of ASD.

CONCLUSION

Atomospheric exposure to various chemical species and microbiological materials carrying ASD may affect upper airway inflammation through the production of inflammatory cytokines and mucin.

Distribution of Inflammatory Cells, Adhesion Molecules, Intermediate Filaments, and Chemokine Receptors in Subgroups of Nasal Polyp Patients

Background

The pathogenesis of nasal polyps (NPs) is incompletely understood. The aim of this study was to investigate the distribution of inflammatory cells, adhesion molecules, intermediate filaments, and chemokine receptors in subgroups of NP patients.

Methods

In total, 35 patients were enrolled (group 1, 10 patients with Samter syndrome; group 2, 10 patients with diffuse polyposis without signs of Samter syndrome; group 3: 5 patients with solitary nasal polyps; group 4, 10 controls). Immunohistochemical staining was performed for CD105, CD106, CD62E, CD4, CD8, CXCR4, CD147, CD90, CD104, BF45, vimentin, pancytokeratin, and muscle-specific actin (MSA) in all patients’ specimens.

Results

Expression of CD4, CD8, and CD106 were similar between the groups. Number of patients expressing CD4 in groups 1, 2, and 3 were higher than the controls. Number of patients expressing CD8 antigen were significantly higher in all three groups than in the control group. Expression of CD147 in groups 3 and 4 was significantly higher than in groups 1 and 2. CD98 expression was higher in groups 1, 2, and 3 than in group 4. The number of patients expressing vimentin in groups 1, 2, and 3 was significantly higher than in group 4. Immunostaining for pancytokeratin was positive in all patients.

Conclusion

In conclusion, inflammatory cell, adhesion molecule, intermediate filament, and chemokine receptor profiles in nasal polyps differ among different patient groups and control subjects. Additional specific immunohistochemical studies are necessary for development of more specific immunotherapies.

Mometasone and desloratadine additive effect on eosinophil survival and cytokine secretion from epithelial cells

Background

Although antihistamines and topical corticosteroids are used in combination to treat allergic rhinitis, their additive effect has not been yet demonstrated. The aim was investigate the antiinflammatory additive effect of mometasone and desloratadine on cytokine and sICAM-1 secretion by epithelial cells, and on eosinophil survival stimulated by human epithelial cells secretions from nasal mucosa and polyps.

Methods

Epithelial cells obtained from nasal mucosa or polyps were stimulated with 10% fetal bovine serum in presence of mometasone (10^-11M-10^-5M) with/without desloratadine (10^-5M). Cytokine and sICAM-1 concentrations in supernatants were measured by ELISA. Peripheral blood eosinophils were incubated during 4 days with epithelial cell secretions with (10^-11M-10^-5M) and/or desloratadine (10^-5M) and survival assessed by Trypan blue. Results are expressed as percentage (mean ± SEM) compared to control.

Results

Fetal bovine serum stimulated IL-6, IL-8, GM-CSF and sICAM-1 secretion. In mucosa and polyp epithelial cells, mometasone inhibited this induced secretion while desloratadine inhibited IL-6 and IL-8. The combination of 10^-5M desloratadine and 10^-9M mometasone reduced IL-6 secretion (48 ± 11%, p < 0.05) greater extent than mometasone alone (68 ± 10%) compared to control (100%). Epithelial cell secretions induced eosinophil survival from day 1 to 4, this effect being inhibited by mometasone. At day 4, the combination of mometasone (10^-11M) and desloratadine (10^-5M) provoked an increased inhibition of eosinophil survival induced by cell secretions (27 ± 5%, p < 0.01) than mometasone (44 ± 7%) or desloratadine (46 ± 7%) alone.

Conclusions

These results suggest that the combination of desloratadine and mometasone furoate have a greater antinflammatory effect in an in vitro model of eosinophil inflammation than those drugs administered alone.

Iron homeostasis and methionine-centred redox cycle in nasal polyposis

Nasal polyposis is a multifactorial disease with a strong inflammatory component. Its pathogenesis is often associated with ROS production catalysed by redox-active iron. This study aimed to characterize the roles of iron homeostasis and redox status in the pathogenesis of polyposis. Nasal polyps (NP) from asthmatics and non-asthmatics and turbinates from controls and NP-patients were analysed for ferritin, ferritin-bound iron (FBI) and levels of methionine-centred redox cycle proteins. The ferritin content in both NPs was significantly higher than in adjacent turbinates. No differences in FBI were observed between both NP groups and both turbinates groups, while in NPs it was significantly higher. In NP-turbinates the highest levels of redox proteins were observed. In conclusion, re-distribution of iron occurs upon the development of NP. While FBI is elevated in NPs, the adjacent turbinate remain iron-poor and low-inflammatory, suggesting the formation of virtual boundary between these tissues.

Identification of the nasal mucosa as a new target for leptin action

The aim of this study was to examine systemic and local nasal leptin and leptin receptor expression in patients with nasal polyposis and healthy controls.

METHODS AND RESULTS

Serum leptin and soluble leptin receptor levels were examined by enzyme-linked immunosorbent assay (ELISA). The presence of leptin and leptin receptor mRNA was investigated using reverse transcriptase-polymerase chain reaction (RT-PCR), and tissue leptin and leptin receptor protein expression was analysed by immunohistochemistry and ELISA. Serum levels of biologically active leptin were significantly elevated in patients with nasal polyps compared with control subjects. These serum leptin levels were strongly correlated with the levels found in tissue in both study groups, although leptin was not significantly elevated in nasal polyp tissue. Using RT-PCR, we showed that both leptin and its receptors were produced in nasal mucosa. Finally, immunohistochemistry showed that leptin and leptin receptor protein were expressed in several cells of the normal and inflamed nasal mucosa.

CONCLUSIONS

Leptin receptors and their biological ligand leptin are expressed in the nasal mucosa, suggesting a possible role in upper airway immunology.

Lower sensitivity of nasal polyp fibroblasts to glucocorticoid anti-proliferative effects

BACKGROUND

Treatment with glucocorticoids (GCs) is the cornerstone of nasal polyp (NP) therapy, but some patients respond poorly to them. Fibroblasts are involved in both inflammation and remodelling of NP. We aimed to evaluate whether NP fibroblasts are less sensitive to GCs' anti-proliferative and anti-inflammatory effects, compared to nasal mucosa (NM) fibroblasts.

METHODS

Fibroblasts were obtained from NP (n = 8) from asthmatic patients undergoing endoscopic surgery and NM (n = 8) from patients undergoing nasal corrective surgery. Fibroblasts were stimulated with DMEM at 0.5% or 5% FBS, or TGF-β (5 ng/ml), with or without dexamethasone (10(-11) to 10(-5)M) for different times. Cell proliferation, collagen mRNA expression and IL-6 and IL-8 release were measured.

RESULTS

After 3-days, dexamethasone dose-dependently inhibited proliferation of NM (p < 0.001) but not that of NP fibroblasts. Dexamethasone (10(-6)M) reduced by 25% the proliferation of NM fibroblasts. Dexamethasone also inhibited proliferation of NM (p < 0.01) but not that of NP fibroblasts at 5-days. TGF-β induced collagen-1α1, -1α2, and -3α1 mRNA levels in both NM and NP fibroblasts (p < 0.05), and dexamethasone did not alter TGF-β-induced collagen mRNA levels in either fibroblast type at 24 h. Dexamethasone dose-dependently decreased (p < 0.05) FBS-induced IL-6 and IL-8 release in both NM and NP fibroblasts at 4 h, although at 10(-8)M, dexamethasone inhibited cytokine production in NM (p < 0.05) but not in NP fibroblasts.

CONCLUSIONS

This impaired sensitivity of nasal polyp fibroblasts to in vitro glucocorticoid effects concurs in part with the poor clinical response that these nasal polyp patients show to glucocorticoid treatment.

Proinflammatory impact of Staphylococcus aureus enterotoxin B on human nasal epithelial cells and inhibition by dexamethasone

BACKGROUND

The pathophysiology and etiology of chronic rhinosinusitis with nasal polyps (CRSwNP) are poorly understood. Although a potential role of staphylococcal enterotoxins (SE) in the pathogenesis of CRSwNP has been detected, additional studies are needed on the impact of SE on nasal epithelial cells. The purpose of this study was to evaluate the impact of Staphylococcus aureus enterotoxin B (SEB) on proinflammatory cytokine/chemokine releases in primary human nasal epithelial cells (HNEC) of subjects with and without CRSwNP and the inhibitory effect of glucocorticoid on it.

METHODS

Epithelial cells of NP and inferior turbinate (IT) were cultured serum free under stimulus of SEB, and interleukin (IL)-1beta, respectively. Furthermore, the inhibitory effect of glucocorticoid on the proinflammatory response was investigated by addition of dexamethasone. In situ hybridization and Western immunoblot assays were used to investigate the proinflammatory impact of SEB on IL-5 and granulocyte macrophage colony-stimulating factor (GM-CSF) mRNA levels and protein production in HNEC.

RESULTS

Results indicate (1) stimulation of HNEC with SEB resulted in increased IL-5 and GM-CSF expression, which could be suppressed by dexamethasone (p < 0.05), and SEB at concentrations of 1-100 ng/mL effectively promoted IL-5 and GM-CSF release by HNEC (p < 0.05); (2) patients with CRSwNP showed a significantly increased expression of IL-5 and GM-CSF in HNEC than patients without CRSwNP (p < 0.05); and (3) the expression of IL-5 and GM-CSF was significantly up-regulated under the stimulus of SEB compared with IL-1beta (p < 0.05).

CONCLUSION

SEB acts as a superantigen and exhibits a dramatic proinflammatory impact on HNEC, which can be inhibited by the addition of glucocorticoid.

Significance of susceptible gene expression profiles in nasal polyposis

Nasal polyposis (NP) is a common chronic inflammatory disease of the rhinosinus mucosa and a complex disease with strong genetic and environmental components. During the past 10 to 20 yr, many studies have been performed to determine differential gene expression profiles between NP and normal nasal tissues, in order to identify susceptible genes that are associated with NP-related traits. Despite achievement in the identification of candidate genes and their associated pathogenic pathways, the large challenges remain as the genetic and molecular alterations required for its development and progression are still unclear. Therefore, the development of novel, powerful tools for gene discovery, and a closer integration of genetics and medical biology would provide valuable insight into the pathogenesis of NP.

[Injury and epithelial wound healing: a pathophysiologic hypothesis for nasal and sinus polyposis]

Nasal polyposis (NP), asthma, and chronic bronchitis are chronic inflammatory diseases of the upper airways. They may be caused by injury to the respiratory epithelium in a chronic inflammatory environment. Several studies show that during NP nasal epithelial cells are involved in the overexpression of cytokines and growth factors. Among these, transforming growth factor beta1 (TGF-beta1) appears to play a major role in the genesis of NP. Differentiated respiratory epithelium, obtained from in vivo or in vitro models, is used to study wound healing in inflammatory environments, to elucidate the pathophysiology of NP, and to improve understanding and management of upper airway inflammatory diseases.

Effect of desloratadine on epithelial cell granulocyte-macrophage colony-stimulating factor secretion and eosinophil survival

BACKGROUND

Second-generation antihistamines are H(1) receptor antagonists and may have additional anti-inflammatory effects.

OBJECTIVE

The aims of the study were to evaluate the effect of desloratadine (DL) on cytokine secretion by epithelial cells from both nasal mucosa (NM) and polyps (NP), and on eosinophil survival primed by epithelial cell secretions.

METHODS

Epithelial cells were cultured and stimulated with fetal bovine serum (FBS), IL-1beta or TNF-alpha with and without DL for 24 h. Culture supernatant cytokines concentration were measured by ELISA. Peripheral blood eosinophils were incubated with human epithelial cell conditioned media (HECM) and DL. Eosinophil survival was assessed by Trypan blue dye exclusion. Results are expressed as mean+/-SEM of cytokine concentration (pg/mL) or eosinophil survival index (%).

RESULTS

FBS increased granulocyte-macrophage colony-stimulating factor (GM-CSF), vascular endothelial growth factor (VEGF), IL-6, IL-8, and TGF-beta(1) secretion in epithelial cell cultures from both NM and NP. Only GM-CSF secretion was significantly (P<0.05) inhibited by a dose-response of DL compared with positive controls, in both NM (10(-5) m: 125+/-36 pg/mL, 10(-6) m: 95+/-22 pg/mL vs. control: 256+/-91 pg/mL, n=6) and NP (10(-5) m: 80+/-29 pg/mL, 10(-6) m: 109+/-45 pg/mL vs. control: 333+/-212 pg/mL, n=6). DL also showed an inhibitory effect on HECM-induced eosinophil survival from both NM and NP. At 72 h, DL significantly (P<0.01) inhibited eosinophil survival induced by HECM from NM (10(-5) m: 19.9+/-5.5%, n=9; 10(-6) m: 28.7+/-7.7%, n=9) and NP (10(-5) m: 6.2+/-2.8%, n=11) compared with HECM alone (NM: 42.1+/-7.3%; NP: 45.3+/-8.1%).

CONCLUSION

The inhibitory effects of DL on epithelial cell GM-CSF secretion and on eosinophil survival induced by epithelial cell secretions, suggest that this H(1) antagonist may regulate eosinophil inflammation in upper airways.

Maximal medical therapy for chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is widely recognized as one of the most common, if not the most common, chronic disease entities. This article discusses CRS without nasal polyposis. The discussion of maximal medical therapy concentrates on the best available evidence from published clinical trials.

Pathogenesis of nasal polyps: an update

The cause of nasal polyp formation is still unknown. Genetic predisposition has been suggested, but there are scanty data to support such theories. Activated epithelial cells may be the major source of mediators inducing influx of inflammatory cells (mostly eosinophils) and proliferation and activation of fibroblasts leading to nasal polyp formation. Infectious agents (including viruses, bacteria, or fungi) may be potential primary factors activating nasal epithelial cells. Proinflammatory cytokines and growth factors play important roles in the persistence of mucosal inflammation associated with nasal polyps. Arachidonic acid metabolites seem to be particularly important in the pathogenesis of nasal polyps in patients with aspirin hypersensitivity rhinosinusitis/asthma syndrome.

Effect of mitomycin C on the secretion of granulocyte macrophages colonies stimulating factor and interleukin-5 in eosinophilic nasal polyps stromal culture

The research involving tissue factors, such as granulocyte macrophage colonies stimulating factor (GM-CSF) and interleukin 5 (IL-5), leads to the mechanisms involved in the maintenance of eosinophilia, which is essential for the pathogenesis on eosinophilic nasal polyps. Mitomycin C has been successfully used in otolaryngology. Aim: The objective of this study was to evaluate the effect of mitomycin C in secretion of GM-CSF and IL-5 on eosinophilic nasal polyps. Study design: case-control. Material and Method: This is a comparative and auto-matched experimental study, performed with fragments of polyps which had been obtained from biopsy of patients with eosinophilic nasosinusal polyposis. The fragments of the experimental group were treated with mitomycin C (400 microg/ml) for 5 minutes and then washed in RPMI substrate. At time zero, 12 and 24 hours, the surface material was taken to determination of its GM-CSF levels in 22 patients and of IL-5 levels in 19 patients, by ELISA method. Results: Reduction in GM-CSF expression on the experimental group at time 24 h (p<= 0.05). The treated group presented significant GM-CSF expression between zero time and 12 h time (p=0.013) showing the culture viability such as in the non-treated group. Tendency to decreasing IL-5 levels on the treated groups at 24 hours. Conclusion: This study showed that mitomycin C was efficient in inhibiting GM-CSF synthesis with reduction of IL-5 secretion, but this fact needs complementary studies.

Retinoic acid-inducible gene-I is induced by interleukin-1beta in cultured human gingival fibroblasts

Retinoic acid-inducible gene-I (RIG-I) is a member of the DExH box family protein, and details of its biological function are not known. We have studied the mechanism of the interleukin-1beta (IL-1beta)-induced RIG-I expression in human gingival fibroblasts in culture. We also addressed the possibility of enhanced expression of COX-2, RANTES and galectin-9 in fibroblasts overexpressed RIG-I. We stimulated cultured human gingival fibroblasts with IL-1beta and examined the expression of RIG-I mRNA and protein by reverse transcriptase-mediated polymerase chain reaction and Western blot analysis. The effect of cycloheximide, a protein synthesis inhibitor, on the IL-1beta-induced expression of RIG-I was examined. The expression of COX-2, RANTES, galectin-9 and monocyte chemoattractant protein-1 in gingival fibroblasts transfected with RIG-I cDNA was also examined. IL-1beta stimulated the expressions of mRNA and protein for RIG-I, in cultured fibroblasts, in a time- and concentration-dependent manner. Cycloheximide did not suppress the IL-1beta-induced RIG-I expression. Introduction of RIG-I cDNA into fibroblasts resulted in enhanced expression of COX-2 mRNA, and slightly enhanced the expression of mRNA for RANTES and galectin-9. In contrast, RIG-I overexpression did not alter the level of mRNA for monocyte chemoattractant protein-1. We conclude that IL-1beta stimulates RIG-I expression in human gingival fibroblasts.

Superantigens and nasal polyps

Nasal polyps represent an often severe T-cell-orchestrated eosinophilic upper airway disease with currently unknown pathogenesis, often associated with lower airway disease, such as asthma. Superantigens, predominantly derived from Staphylococcus aureus, are potent activators of T cells, induce the synthesis of IgE in B cells, and have direct effects on pro-inflammatory cells, such as eosinophils. IgE antibodies to S. aureus enterotoxins have been described in polyp tissue, linked to a local polyclonal IgE production and an aggravation of eosinophilic inflammation. Furthermore, such IgE antibodies have also been described in the sera of patients with asthma, and linked to severity of disease and steroid insensitivity. This review summarizes our current understanding of the possible role of S. aureus enterotoxins in chronic severe airway disease, such as nasal polyposis.

Transcription and translation of the chemokines RANTES and MCP-1 in nasal polyps and mucosa in allergic and non-allergic rhinopathies

The pathogenetic findings of rhinopathies show an increase in infiltrating cells including eosinophils. RANTES is a beta chemokine in which the cysteines are adjacent (C-C), and it attracts and activates eosinophil. We hypothesize that RANTES is locally produced within the nasal polyp microenvironment and is responsible for the inflammatory cell recruitment present in nasal polyposis. To test this hypothesis, we evaluated nasal polyps and mucosa from allergic and control, non-allergic patients for RANTES content. The relative levels of RANTES and MCP-1 protein in tissue homogenates were quantified using enzyme-linked immunosorbent assay technology, and quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) tests for RANTES and MCP-1 mRNA expression were performed. The results indicate that RANTES expression and production increase in nasal mucosa (septal and turbinate portions) of allergic patients compared to the same mucosa in non-allergic patients. In allergic patients, RANTES levels of nasal polyp homogenates were nearly 12-fold higher than the RANTES levels in mucosa homogenate. In this study, we hypothesize that the particular anatomic structure and physiologic function of the turbinates are more involved in the pathogenesis of rhinitis and may undergo polypoid degeneration in allergic rhinitis than any other anatomical structure of the nose. Our data suggest that RANTES is more involved than MCP-1 in recruiting inflammatory cells in rhinological disease and may reflect the degree of local inflammation as consequence of the specific chemoattractant properties of RANTES. The level of RANTES in nasal polyps could be important in the development of the pathological state.

Interleukin (IL)-4 and to a lesser extent either IL-13 or interferon-gamma regulate the production of eotaxin-2/CCL24 in nasal polyps

BACKGROUND

Eotaxin-2/CCL24 is a potent eosinophil attractant that has been implicated in the recruitment of eosinophils in allergic disease. We have investigated whether the cytokines interleukin (IL)-4, IL-13, and interferon (IFN)-gamma regulate eotaxin-2/CCL24 in nasal polyps.

METHODS

Nasal polyps were cultured in the presence of the cytokines described above and the concentration of eotaxin-2/CCL24 was measured in the culture supernatant.

RESULTS

IL-4 was found to be the major stimulus for eotaxin-2/CCL24 production from nasal polyps followed by IL-13 and IFN-gamma. IL-4 induced eotaxin-2/CCL24 in a dose-dependent manner with concentrations as low as 0.1 ng/ml being able to induce eotaxin-2/CCL24. By immunohistochemistry, eotaxin-2/CCL24 immunoreactivity was localized to mononuclear cells in the IL-4 stimulated nasal polyp tissue. Interestingly, nasal turbinates obtained from patients suffering from nonallergic rhinitis (vasomotor rhinitis) were also found to release eotaxin-2/CCL24 both spontaneously and following cytokine stimulation with IL-4 and IFN-gamma being major inducers of this cytokine.

CONCLUSIONS

All together these findings suggest that Th1 and Th2 cytokines may regulate eotaxin-2/CCL24 production in nasal polyps and nonallergic rhinits.

Mediators in nasal polyposis

Nasal polyposis (NP) is a chronic inflammatory disease of the sinuses often associated with asthma. Although we have not yet achieved a full understanding of the precise mechanisms underlying the pathogenesis of NP, recent insights have been acquired into the regulation of eosinophil chemotaxis, activation, and survival, in addition to their possible link to gross histopathologic changes such as pseudocyst formation. Interleukin (IL)-5, transforming growth factor-beta(1), and eotaxin seem to be crucial players in the regulation of eosinophilic inflammation and extracellular matrix breakdown. The cytokine pattern in NP assumes neither a T helper 1 (Th1) nor Th2 type predominance, because IL-4, IL-5, IL-12, and interferon-gamma have all been shown to be upregulated in NP tissue, without influence of the atopic status. However, recent studies have demonstrated a strong local upregulation of the immunoglobulin E (IgE) synthesis with the formation of specific IgE to Staphylococcus aureus enterotoxins, suggesting a possible role of superantigens in these pathologic processes.

Exposure to 200 ppm of methanol increases the concentrations of interleukin-1beta and interleukin-8 in nasal secretions of healthy volunteers

This study was designed to investigate subclinical irritating effects of methanol on functional and immunologic parameters in human respiratory epithelia. Twelve healthy, nonsmoking individuals were exposed to concentrations of 20 and 200 ppm of methanol in an exposure chamber. The concentrations of interleukin (IL)-8, IL-1beta, IL-6, and prostaglandin E2 (PGE2) were monitored. The saccharin transport time test was used to evaluate mucociliary transport. Video interference contrast microscopy was used to determine the ciliary beat frequency of nasal epithelial cells. Subjective symptoms were assessed with a questionnaire. The median concentrations of IL-8 and IL-1beta were significantly elevated after exposure to 200 ppm of methanol as compared to exposure to 20 ppm (IL-1beta, 21.4 versus 8.3 pg/mL, p = .001; IL-8, 424 versus 356 pg/mL, p = .02). The release of IL-6 and PGE2 did not change significantly (IL-6, 10.3 versus 6.5 pg/mL, p = .13; PGE2, 13.6 versus 13.4 pg/mL), nor did the ciliary beat frequency or the saccharin transport time. Both IL-8 and IL-1beta proved to be sensitive indicators for subclinical irritating effects of methanol in vivo. The German threshold limit of 200 ppm of methanol does not prevent subclinical inflammatory reactions of the nasal respiratory mucosa.

Nuclear factor-kappa B activation in the nasal polyp epithelium: relationship to local cytokine gene expression

OBJECTIVES

A panel of cytokines has been found to be important for eosinophil accumulation and activation in nasal polyps. The aims of this study were to ascertain whether the activation of nuclear factor-kappa B (NF-kappaB) occurred in the polyp epithelium, and to examine the relationship between the degree of activation and local cytokine gene expression.

STUDY DESIGN/METHODS

Nasal polyp specimens were obtained from 26 untreated patients. The proportion of nuclear translocation of the NF-kappaB p50 subunit in the polyp epithelium was quantitatively analyzed by a combination of fluorescent immunohistochemistry and a laser scanning confocal microscope image system. The levels of GM-CSF, IL-5, IL-8, IL-16, and eotaxin mRNA expression in the same speci-mens were measured using reverse transcription-polymerase chain reaction.

RESULTS

Both cytoplasmic and nuclear localization of the p50 subunit was observed mainly in the epithelial layer in all specimens. The percentages of epithelial cells with nuclear translocation ranged from 4.5% to 40.5% (median, 18%). Significant correlations were observed between the degree of epithelial NF-kappaB activation and the levels of IL-8, IL-16, and eotaxin mRNA expression (r = 0.468, 0.47, and 0.739, respectively).

CONCLUSION

The activation of NF-kappaB in the nasal polyp epithelium is responsible for the recruitment of inflammatory cells, particularly eosinophils, through the initiation of the transcriptional pathway of the related cytokines. The increased NF-kappaB activity in the polyp epithelium may reflect hypersensitivity to unknown stimuli.

Late phase responses after nasal challenges with allergen and histamine in asthmatic children with perennial nasal allergy

OBJECTIVE

Late phase response (LPR) is difficult to investigate in patients with perennial nasal allergy because of their continuous presentation with nasal symptoms. Contribution of histamine to the LPR is also controversial. In this study, we investigated whether exogenous histamine can induce LPR in asthmatic patients with perennial nasal allergy to house dust.

METHODS

A total of 40 asthmatic children were divided into clinical, subclinical and non-rhinitis groups based on their daily nasal symptoms. Changes in nasal patency and in inflammatory cells in nasal secretion were quantitatively measured for 6 h by acoustic rhinometry and light microscopy respectively before and after nasal challenge with allergen or histamine.

RESULTS

The allergen challenge produced a significant biphasic decrease in nasal patency in the subclinical group and a marginal decrease in the clinical group, with increases in eosinophils 6 h after the challenge. By contrast, histamine challenge induced significant responses in the clinical group and only a slight response in the subclinical group. Eosinophils also accumulated in nasal secretion of the clinical group to significant levels 6 h after histamine challenge. Eosinophil accumulation following histamine challenge was earlier than that after exposure to allergen.

CONCLUSION

We conclude that LPR can be demonstrated in asthmatic children with perennial nasal allergy. Exposure to exogenous histamine also induced LPR, mediated mainly by eosinophil-related mediators.

Reduced expression of activin A in focal lymphoid agglomerates within nasal polyps

It has been previously reported that activin A, a homodimer of the betaA inhibin subunit, is secreted by stromal cells from mouse bone marrow and causes apoptotic death of mouse plasmacytoma tumor cells. Recent in vitro studies have also implicated this cytokine in the suppression of normal B-cell lymphopoiesis. In this study we examined the occurrence of activin A in nasal polyp tissues that present a combination of epithelium, mesenchyme, and vascular endothelium, with frequent massive hemopoietic infiltration. Anti-betaA-chain antibodies strongly stained epithelial mucous glands and some endothelial cells, and diffusely stained the polyp stroma. Normal adult conchae were similarly stained, whereas activin A was not detected prenatally by immunostaining of nasal tissues. Staining specificity was substantiated by ligand competition assays. Detailed examination of the inflammatory polyp infiltrate showed that activin A staining was reduced in sites of focal infiltration of B-lymphoid cells. It is therefore implied that local accumulation of a large number of B-cells is associated with relatively low activin A expression.

Mode of action of intranasal corticosteroids

The mode of action of intranasal corticosteroids (INCS) is complex. It is not known whether INCS penetrate the nasal mucosa or act on target cells; however, their low systemic activity supports the concept of local action on nasal mucosa. This local effect can nonetheless influence a variety of inflammatory cells and their mediators such as epithelial cells, lymphocytes, basophils, mast cells, and Langerhans cells. Corticosteroid-induced inhibition of immunoglobulin E-dependent release of histamine is a possible but unproven mode of action. Epithelial cells are an important target for corticosteroids, and INCS concentration is high at the epithelial surface. INCS may combine with the corticosteroid receptors in epithelial cells, which are then expelled into the airway lumen together with the dead epithelial cells or migrating inflammatory cells. A reduced influx of mediator cells may explain some of the effects of INCS on rhinitis symptoms, but it cannot explain all of the effects because INCS also reduce the early-phase sneezing and rhinorrhea after an allergen challenge outside the pollen season. In this situation, the number of surface mast cells/basophils is very low, as it is in the absence of allergic rhinitis. The mechanism by which INCS treatment of allergic rhinitis reduces itching, sneezing, and rhinorrhea, the characteristic symptoms of an early-phase response involving mast cell release of histamine, remains to be determined. Studies should be conducted to characterize the broad range of mechanisms by which INCS produce their therapeutic effects in allergic rhinitis.

Effect of budesonide and nedocromil sodium on IL-6 and IL-8 release from human nasal mucosa and polyp epithelial cells

We investigated the effect of budesonide and nedocromil sodium on the secretion of IL-6 and IL-8 by cultured epithelial cells from healthy nasal mucosa and nasal polyps. Human epithelial cell conditioned media was generated with fetal calf serum (FCS) in the presence or absence of budesonide and/or nedocromil sodium. Budesonide inhibited FCS-induced IL-6 and IL-8 release in a dose-dependent manner. The IC25 (25% inhibitory concentration) of budesonide on IL-6 release was higher in nasal polyp than in nasal mucosa epithelial cells (34 nM vs. 200 pM). The IC25 of budesonide on IL-8 release was higher in nasal mucosa than in nasal polyps (145 pM vs. 4 pM). Nedocromil sodium caused a dose-related inhibitory effect on IL-8 release from nasal mucosa (IC25, 207 nM), while it only had a significant effect in nasal polyps at 10(-5) M. Nedocromil sodium had no effect on IL-6 release. The inhibitory effect of budesonide was higher than that of nedocromil sodium on both nasal polyps and nasal mucosa. Budesonide and nedocromil sodium may exert their anti-inflammatory action in the respiratory mucosa by modulating the secretion of IL-6 and IL-8. The different effect of budesonide and nedocromil sodium on IL-6 and IL-8 release may be explained by differences in the mechanisms which regulate the upregulation of these cytokines in inflammatory responses.

Granulocyte-macrophage colony stimulating factor up-regulates CCR1 in human neutrophils

Neutrophils (polymorphonuclear leukocytes; PMN) are phagocytic cells instrumental in the clearance of infectious pathogens. Human PMN are commonly thought to respond primarily to chemokines from the CXC family. However, recent findings suggest that under specific cytokine activation conditions, PMN can also respond to some CC chemokines. In this study, the effect of GM-CSF, a well-characterized PMN priming and maturation factor, on CC-chemokine receptor (CCR) expression in PMN was investigated. Constitutive expression of CCR1 and CCR3 mRNA in PMN was detected by ribonuclease protection assay. Following incubation of PMN with GM-CSF (0.01-10 ng/ml; 6 h) CCR1 mRNA expression was rapidly (approximately 1 h) up-regulated. In contrast, no significant induction of CCR2, CCR3, CCR4, or CCR5 mRNA was observed. CCR1 protein was also up-regulated by GM-CSF stimulation. GM-CSF-induced up-regulation of CCR1 showed functional consequences because GM-CSF-treated PMN, but not control cells, responded to the CC chemokines macrophage inflammatory protein-1alpha, monocyte chemoattractant protein-3, and RANTES in assays of chemotactic migration and intracellular calcium mobilization. These results suggest that PMN activated by the proinflammatory cytokine GM-CSF can change their receptor expression pattern and become responsive to CC chemokines.