Effects of glucocorticoids on infiltrating cells and epithelial cells of nasal polyps

The role and mechanism of extracellular traps in chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a common inflammatory disease of the nose that affects millions of individuals worldwide. Recent research has introduced the concept of an immunologic endotype based on the pathological characteristics of CRS and the types of inflammatory cell infiltration. This endotype concept is conducive to understanding CRS pathology and guiding further targeted therapy. Eosinophils and neutrophils infiltrate different proportions in different CRS endotypes and release extracellular traps (ETs) as a response to the extracellular immune response. The mechanisms of formation and biological roles of ETs are complex. ETs can trap extracellular microorganisms and limit the range of inflammation to some extent; however, excessive and long-term ETs may be related to disease severity. This review summarises and explores the mechanism of ETs and the advances in CRS research and proposes new insights into the interaction between ETs and programmed cell death (including autophagy, pyroptosis, and necroptosis) in CRS, providing new ideas for the targeted therapy of CRS.

TNF-α Regulates the Glucocorticoid Receptor Alpha Expression in Human Nasal Epithelial Cells Via p65-NF-κb and p38-MAPK Signaling Pathways

Background

Tumor necrosis factor (TNF)-α induces changes in the glucocorticoid receptor (GR) isoforms' expression in human nasal epithelial cells (HNECs) in chronic rhinosinusitis (CRS).

Objective

However, the underlying mechanism of TNF-α induced GR isoforms' expression in HNECs remains unclear. Here, we explored changes in inflammatory cytokines and glucocorticoid receptor alpha isoform (GRα) expression in HNECs.

Materials and Methods

To explore the expression of TNF-α in nasal polyps and nasal mucosa of CRS, fluorescence immunohistochemical analysis was employed. To investigate changes in inflammatory cytokines and GRα expression in HNECs, RT-PCR and western blotting were performed following the cells' incubation with TNF-α. Cells were pretreated with the nuclear factor-κB gene binding (NF-κB) inhibitor QNZ, the p38 inhibitor SB203580, and dexamethasone for one hour, then a TNF-α. Western blotting, RT-PCR, and immunofluorescence had been utilized for the cells' analysis and the ANOVA for the data analysis.

Results

The TNF-α fluorescence intensity was mainly distributed in nasal epithelial cells of nasal tissues. TNF-α prominently inhibited the expression of GRα mRNA from 6 to 24 h in HNECs. GRα protein was decreased from 12 to 24 h. Treatment with QNZ, SB203580, or dexamethasone inhibited the TNF-α and interleukin (IL)-6 mRNA expression and increased the GRα levels.

Conclusion

TNF-α induced changes in the GR isoforms' expression in HNECs, and it was mediated through p65-NF-κB and p38-MAPK signal transduction pathways, which could be considered a promising neutrophilic CRS treatment.

Major basic protein deposited at intra mucosal epithelium with probable eosinophilic chronic rhinosinusitis

Background

Eosinophilic chronic rhinosinusitis (ECRS) is diagnosed by Japanese Epidemiological Survey of Refractory Eosinophilic Chronic Rhinosinusitis (JESREC) scoring system and histopathological eosinophil counts of dissected nasal polyps. Patients with low JESREC score and small number of tissue eosinophils are diagnosed with non-ECRS (NECRS). Due to the 2 parameters of this diagnostic system, chronic rhinosinusitis is to be divided to 4 groups and some patients fall into the 2 groups other than ECRS and NECRS: probable ECRS (pECRS) and probable non-ECRS (pNECRS). We attempted to clarify clinical and histopathological similarities and differences, especially concerning major basic protein (MBP), among those groups.

Methods

One hundred twenty-eight patients treated by endoscopic sinus surgery was included. Clinical characteristics were compared among each group, and immunohistological analysis for MBP was performed to 35 randomly selected patients. MBP deposition at intra mucosal epithelium was evaluated by semiquantificational approach.

Results

ECRS patients showed significantly higher comorbidity rate with allergic rhinitis (36 patients, 78.3%), asthma (36 patients, 78.3%) compared with other groups. Also, percentage of the patients complaining olfactory dysfunction (42 patients, 91.3%) was significantly higher (p < 0.001). Lund-Mackay score (mean, 14.5; 6–24) and recurrence rate (27 patients, 61.4%) was the highest in ECRS patients. Regarding pECRS, the number of patients with olfactory dysfunction (5 patients, 55.6%) was higher than pNECRS and NECRS groups. Also, comorbidity of asthma and percentage of blood eosinophils tended to be higher than those 2 groups. MBP score of pECRS group was significantly higher than NECRS (p < 0.05), despite of smaller tissue eosinophil counts.

Conclusion

pECRS might share some characteristics with ECRS although tissue eosinophil count was significantly smaller compared with ECRS. The results of this study have shown that MBP score in pECRS nasal polyps was significantly higher than NECRS patients and close to ECRS. That might suggest that eosinophils have existed in the nasal polyps of pPECRS patients at some point before surgery.

Expression of Estrogen Receptor-alpha in Nasal Polyps and the Effects of Dexamethasone on Estrogen Receptor-alpha Expression in RPMI 2650 Cells

BACKGROUND

Studies have reported that epithelial cell proliferation may be involved in the pathogenesis of nasal polyps (NPs). Estrogen receptor (ER)-α, one type of ER, is related to anti-inflammatory action and cell survival in certain tissues. In this study, we examined the presence or absence of ER-α in NPs and healthy inferior turbinate mucosae. We also investigated the effect of dexamethasone on ER-α expression, cell viability, and apoptosis in RPMI 2650 cells.

METHODS

Immunohistochemical staining and Western blot analysis were conducted to determine the expression of ER-α in 15 NPs and 15 healthy inferior turbinate mucosae. After treating RPMI 2650 cells with dexamethasone, ER-α expression was analyzed using Western blot analysis and cell viability was determined using the MTT assay. Western blot analysis and annexin V-phycoerythrin (PE) staining were used to examine apoptotic cell death.

RESULTS

Western blot analysis showed that ER-α expression was upregulated in 13 of the 15 NP tissues. Immunohistochemical staining for ER-α confirmed the results of the Western blot analysis. When RPMI 2650 cells were treated with dexamethasone, both ER-α expression and cell viability were decreased. Furthermore, the treatment of RPMI 2650 cells with dexamethasone increased apoptotic cell death, as shown by increased levels of BAX and cleaved caspase-3, decreased levels of Bcl-2, and an increased percentage of positive annexin V-PE stained cells.

CONCLUSION

ER-α expression was higher in NPs than in healthy inferior turbinate mucosae. When RPMI 2650 cells were treated with dexamethasone, ER-α expression was downregulated, cell viability decreased, and apoptosis increased. The decreased cell viability may be related, at least in part, to the decreased ER-α protein levels, which likely contributed to the induction of apoptotic cell death in RPMI 2650 cells.

In Vitro Treatment with 2-APB Inhibits the Inflammation in Nasal Polyps

OBJECTIVE

Glucocorticoids are considered the main treatment option for chronic rhinosinusitis with nasal polyps (CRSwNP), but their effect rate ranges from 60.9% to 80%. Novel therapeutic means should be studied. The purpose of this study was to investigate the expression of Orai1 in nasal polyps (NPs) and the influence of intervention of Orai1 on NPs after in vitro treatment of 2-aminoethoxydiphenyl borate (2-APB).

STUDY DESIGN

Prospective cross-sectional study.

SETTING

University hospital.

SUBJECTS AND METHODS

Nasal biopsy samples were obtained from normal subjects or subjects with CRSwNP. We studied the localization of Orai1 protein in NPs by using immunohistochemistry. Then these tissues in cultures were maintained in the absence or presence of dexamethasone (DEX) or 2-APB. Orai1 was examined by Western blot, enzyme-linked immunosorbent assay (ELISA), and real-time reverse transcription-polymerase chain reaction (RT-PCR). Inflammatory mediators including interleukin (IL)-1β, IL-5, eosinophil cation protein (ECP), leukotriene (LT)C4, interferon (IFN)-γ, and dermatophagoides pteronyssinus (DP)-specific immunoglobulin E (sIgE) as well as mucins (MUCs) including MUC5B and MUC7 in cultures were analyzed with ELISA and real-time RT-PCR.

RESULTS

The expression of Orai1 was localized to cytoplasmic membrane of inflammatory cells and submucosal glandular cells and was upregulated in NPs compared with normal nasal mucosa. Orai1 was decreased in NPs after in vitro treatment of 2-APB but not after DEX intervention. The levels of inflammatory mediators and mucins were reduced more after 2-APB treatment when compared with those after DEX treatment.

CONCLUSION

Orai1 may play crucial roles in NP formation, and the intervention of Orai1 may inhibit NP development.

Upper airway stem cells: understanding the nose and role for future cell therapy

The nose together with the paranasal sinuses has an approximate surface area of 100 to 200 cm(2) in adults, which is lined with pseudostratified columnar ciliated epithelium. It serves several important physiological functions such as conditioning and filtration of the inspired air and the provision of end organ for the sense of smell. It is also a physical and immunological barrier as it is the first site of interaction between the host tissue and foreign invaders (viruses, bacteria, and allergens). Our understanding of the complex cellular events occurring in response to inhaled agents during the development of common airway diseases has been significantly enhanced by the current status of in vivo and in vitro nasal experimental models. This will allow the development of novel therapeutic strategies designed to improve the physiological and immune defense functions of the nasal epithelium, as well as novel therapies for other common nasal diseases.

Dexamethasone Induces Apoptosis of Nasal Polyp-Derived Tissue Cultures Through JNK and p38 MAPK Activation

Objectives

Glucocorticoids, such as dexamethasone (DEX), increase apoptosis in a variety of white cells in nasal polyps and apoptosis is an important factor in the resolution of inflammation. However, the mechanism of glucocorticoids induced apoptosis in nasal polyp remains unclear. In this study the authors evaluated which pathways were engaged in apoptosis induced by DEX in an ex vivo model of nasal polyps.

Methods

Nasal polyp tissues were cultured using an air-liquid interface method. Cultures were maintained in the absence or presence of DEX (10 or 100 µM) for 24 hours. To investigate the involvement of the apoptotic signaling pathways in nasal polyp, such as caspase cascades, Fas-FasL signaling pathway, mitochondrial pathway and p38 mitogen-activated protein kinase (MAPK)/JNK pathway, the authors performed reverse transcription-polymerase chain reaction and Western blotting.

Results

The expression ratios of FasL, activated form of caspase-8, caspase-9, and caspase-3 were significantly higher in DEX-treated polyps (P<0.01). In the Bcl-2 family expression, the anti-apoptotic molecules, Bcl-2 and Bcl-XL decreased, but pro-apoptotic molecules, Bax increased, and Bid and Bad were activated. In the conventional MAPKs, JNK, and the phospho-p38 MAPK were significantly higher, but phospho-extracellular signal-regulated kinase (ERK)1/2 was significantly lower in DEX-treated polyps (P<0.01).

Conclusion

DEX induces apoptosis of nasal polyp via caspase cascades, Fas-FasL signaling pathway, mitochondrial pathway and p38 MAPK/JNK pathway.

Systemic prednisone administration selectively alters granulocyte subsets in nasal polyps from aspirin-exacerbated respiratory disease and chronic rhinosinusitis patients

BACKGROUND

Nasal polyps (NPs) are hallmark inflammatory lesions of sinusitis. Despite the spectrum of NP conditions, cellular differences between NPs from patients with chronic rhinosinusitis with NPs (CRSwNP) and aspirin-exacerbated respiratory disease (AERD) are poorly understood. NPs are associated with abundant eosinophils; the contributions of neutrophil and basophil granulocytes are less defined. We therefore sought to assess granulocyte subpopulations, and differential effects following prednisone pretreatment, within NPs of CRSwNP and AERD patients.

METHODS

NPs, adjacent ethmoid sinus tissue, and peripheral blood mononuclear cells (PBMCs) were obtained from patients undergoing endoscopic sinus surgery. Samples from 5 cohorts: CRSwNP ± prednisone (n = 6 each), AERD ± prednisone (n = 6 each), and controls (n = 9), were analyzed by high-dimensional flow cytometry to gate granulocyte populations. Specimens were also assessed using immunohistochemistry (IHC) staining.

RESULTS

Systemic prednisone administration was associated with a lower frequency of eosinophils (p < 0.0001, n = 6) in NPs in both CRSwNP and AERD patients, whereas a decrease in neutrophils (p = 0.0070, n = 6) in NPs was only observed in CRSwNP patients after prednisone treatment. In contrast, steroids do not alter basophil proportions (p = 0.48, n = 6) within NPs from either group. No significant shift in granulocyte subsets after steroid treatment was identified in the adjacent ethmoid mucosa or PBMCs from the same patients. Immunohistochemistry (IHC) staining supported these findings.

CONCLUSION

Granulocyte subpopulations are focally affected within NPs by systemic steroid exposure, without notable granulocyte alterations in the surrounding regional tissues. These data provide direct insights into the cellular effects of routine prednisone exposure in CRS patients, and highlight a unique microenvironment present within NP lesions.

Nasal polyposis in lung transplant recipients with cystic fibrosis

BACKGROUND

Chronic rhinosinusitis with nasal polyposis is common in patients with cystic fibrosis (CF). There are still many open questions regarding factors related to this condition. Furthermore, the prevalence of nasal polyposis and its implications for the outcomes in lung transplant recipients with cystic fibrosis are unknown.

METHODS

All CF patients who underwent lung transplantation at our centre between November 1992 and December 2009 were included. Nasal polyp status was determined endoscopically at time sinus surgery and its relationships to gender, age at lung transplantation, Liou raw score, body mass index, FEV1%predicted, diabetes mellitus, pre-transplant pseudomonas colonisation of the sinuses and the lungs, pre-transplant corticosteroid use and type of mutation of the CFTR gene were analysed. The post-transplant survival times and the incidence of bronchiolitis obliterans syndrome in patients with or without nasal polyposis were compared.

RESULTS

Nasal polyps were found in 19% (17 patients) of the 89 lung transplant recipients, whose data was available for statistical analysis. None of the factors analysed was related to the nasal polyp status. The post-transplant survival times and the incidence of bronchiolitis obliterans syndrome did not significantly differ between patients with or without nasal polyposis.

CONCLUSIONS

CF-related nasal polyposis occurs in a relevant fraction of lung transplant recipients. A specific effect of nasal polyposis on post-transplant outcome could not be confirmed. Nevertheless, there was a trend to NP recurrence in patients with post-transplant sinonasal pseudomonas colonisation and is a tendency of less chronic rejection in CF patients with nasal polyps.

The effects of systemic, topical, and intralesional steroid treatments on apoptosis level of nasal polyps

OBJECTIVE

The purpose of this study was to compare the apoptotic responses to systemic, topical, and intrapolyp injection of glucocorticoid with no treatment in nasal polyps.

STUDY DESIGN

Prospective, randomized controlled study.

SETTING

Tertiary training hospital.

SUBJECTS AND METHODS

The study was performed on 48 patients with nasal polyposis in the Department of Otorhinolaryngology between 2008 and 2009. Patients were assigned to 1 of 4 groups of 12 patients. Group A was treated with oral methylprednisolone 1 mg/kg/d, and the dose was tapered gradually. Group B received 0.3 mL triamcinolone acetonide (40 mg/mL), which was injected into polyp tissue. Group C was treated with topical 55 µg triamcinolone acetonide 2 times daily for 1 month. Group D received no medication. Samples were collected endoscopically after the seventh day for groups A and B, the first month for group C, and the first visit for group D. Apoptotic indexes were determined using the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling method.

RESULTS

Statistically significant differences in apoptotic index were found between each steroid-medicated group and the control group (P (D-A) = .0001; P (D-B) = .003; P (D-C) = .026) and between groups A and C (P (A-C) = .012). Group B did not differ significantly from either group A or C (P (A-B) = .11; P (B-C) = .75).

CONCLUSIONS

The apoptotic index in nasal polyps treated with systemic, topical, and intrapolyp injection forms of glucocorticoids was higher than that in the control group. Systemic steroid treatment induced the most apoptosis.

Lactoferrin inhibits the growth of nasal polyp fibroblasts

The aim of this study was to evaluate the effects of lactoferrin (LF) on the growth of fibroblasts derived from nasal polyps. We showed that the proliferation of fibroblasts was inhibited in a dose-dependent manner by both native and recombinant LF. The greatest inhibition of proliferation was caused by human milk-derived, iron-saturated LF. The inhibition of fibroblast proliferation was not species specific because bovine LF also was active. The interaction between LFs and a putative cell receptor did not depend on the sugar composition of the glycan moiety of the LF molecule because lactoferrins of different origins were active and the addition of monosaccharides to the cultures did not block proliferation. However, the treatment of fibroblasts with sodium chlorate (an inhibitor of glycosaminoglycan sulfation) or the addition of heparin abolished the inhibitory effect of LF, suggesting that LF binds heparan sulfate-containing proteoglycans. The significance of LF in nasal excretions in controlling polyp formation is discussed.

Bax-gene transfer enhances apoptosis by steroid treatment in human nasal fibroblasts

Gene therapy has become a focus not only in the study of cancer but also lifestyle-related diseases. In case of chronic rhinosinusitis with nasal polyps and aspirin-induced asthma, nasal polyps poorly respond to a local administration of steroid. The Bax and Bcl-2 proteins play important roles in the regulation of apoptosis. The treatment of steroid (prednisone) induced apoptosis in the fibroblast. The Bax accelerates apoptosis. Apoptosis is very important in the anti-inflammatory mechanism. In this study, we investigated whether the overexpression of Bax in human fibroblasts influences apoptosis by treatment with a steroid (prednisolone) in vitro. Human nasal fibroblasts were isolated from small pieces of nasal polyp and were transfected with a bax gene-bearing mammalian expression vector. Human nasal fibroblasts were transiently transfected with the expression vector hBaxpcDNA3 (Bax-NF) or native pcDNA3 (Neo-NF). Both transfectants (Bax-NF, Neo-NF) and wild-type-nasal fibroblast (wt-NF) were cultured in conditioning medium and treated with each concentration of prednisolone for 72 h. Prednisolone at a concentration of 10 ng/ml decreased the viability of Bax-NF compared to that of Bax-NF in the absence of prednisolone. The cytotoxicity of prednisolone to Bax-NF was significantly higher than that to Neo-NF or wt-NF (p < 0.01) and the susceptibility of Bax-NF to prednisolone was about 1,000 times that of Neo-NF or wt-NF. We found that the transfer of the exogenous bax gene enhanced the induction of apoptosis by steroid-treatment in human nasal fibroblasts. Therefore, we suggest that exogenous Bax protein expression by gene transfer might be useful for the treatment of nasal polyps. We will further the preclinical study in improving steroids dose and in adopting to transfer bax gene to the nasal polyps by intranasal injection, thus providing a more effective and safer way for the nasal polyps that poorly respond to a local administration of steroids.

Preoperative treatment with topical corticoids and bleeding during primary endoscopic sinus surgery

OBJECTIVE

To find out whether the constant preoperative use of a topical corticoid (mometasone furoate [MF]) could really improve the operative field quality and decrease bleeding during endoscopic sinus surgery (ESS).

STUDY DESIGN

Double-blind, randomized controlled trial.

SETTING

Tertiary referral center.

SUBJECTS AND METHODS

Seventy patients with chronic rhinosinusitis (CRS) with and without polyps underwent ESS under standardized general anesthesia with equal randomization into two groups. During four weeks within the preoperative period, 35 cases were treated with MF, while the other half received placebo matching sprays. Total blood loss, operation time, and surgical field quality were recorded.

RESULTS

Intraoperative blood loss in the MF-treated group was 142.8 mL, less than in the control group (170.6 mL). The difference between the groups is 27.7 mL (95% confidence interval [CI] 3.5-51.92), statistically significant: P = 0.025. Time of surgery was 59 minutes in the MF group and 70 minutes in the control group. The difference was 11.2 minutes (95% CI 2.82-19.51), which is statistically significant: P = 0.009. The quality of the endoscopic surgical field was significantly better for patients treated with MF. Treatment with topical corticoid enables significantly reduced bleeding, decreased operation time, and improved endoscopic vision during ESS for CRS.

CONCLUSION

The use of topical corticoid (MF) in the preoperative period can improve endoscopic vision, reduce bleeding, and decrease operation time in CRS patients with and without polyps undergoing ESS, but our sample size cannot exclude small, and possibly trivial, group differences.

Released intranasal eosinophilic major basic protein as a diagnostic marker for polypoid chronic rhinosinusitis

OBJECTIVE: To investigate the hypothesis that eosinophil major basic protein is released in high concentrations in the nasal mucus of patients with polypoid chronic rhinosinusitis.

STUDY DESIGN: Single center, open, prospective trial.

SETTING: Medical University of Graz, Austria.

SUBJECTS AND METHODS: Patients with polypoid chronic rhinosinusitis (n = 23) were compared to three different control groups: patients with chronic rhinosinusitis-like symptoms but without general mucosal thickening, patients who underwent functional endoscopic sinus surgery for reasons other than chronic rhinosinusitis, and patients without sinus disease (total n = 21). Mucus was harvested from each patient using a standardized technique and analyzed for eosinophil major basic protein with an enzyme-linked immunosorbent assay.

RESULTS: In the patient group with polypoid chronic rhinosinusitis, 20 of 23 (87%) were positive for eosinophil major basic protein. In contrast, only one control patient was positive, whereas the remainder had no detectable amount of eosinophil major basic protein in the mucus ( P = 0.001 vs chronic rhinosinusitis).

CONCLUSION: Toxic eosinophil major basic protein levels are elevated in polypoid chronic rhinosinusitis patients compared to control groups that have similar clinical presentations but upon closer examination turn out not to have chronic rhinosinusitis. In the future, the detection of eosinophil major basic protein in nasal mucus may become a sensitive and specific marker for chronic rhinosinusitis and a helpful diagnostic tool.

© 2010 American Academy of Otolaryngology-Head and Neck Surgery Foundation. All rights reserved.

Narrow-band UVB phototherapy of nasal polyps: results of a pilot study

Nasal polyposis (NP) is characterized by high recurrence rate despite medical and/or surgical treatment. The major mechanism of action of ultraviolet B light (UVB) is induction of apoptosis in inflammatory cells. Therefore phototherapy may represent a new therapeutic approach in NP. A pilot feasibility study was performed to assess the tolerability and clinical efficacy of UVB phototherapy in NP. Thirteen subjects with bilateral grade 1-3 NP were enrolled in an open-labeled prospective pilot study. Patients were exposed to gradually increasing doses of UVB light over a 12 week period (3 exposures/week). Subjects rated their nasal obstruction symptom scores weekly on a visual analogue scale from 0 to 6. The NOSE quality of life questionnaire was used at baseline and end of treatment period. Adverse events were monitored by endoscopy. Ten subjects completed the study. Nasal obstruction symptom scores and quality of life (NOSE) improved at end of treatment compared to baseline. Treatments were well tolerated and no device related adverse events were reported. The results suggest that phototherapy may represent a potential new treatment option in nasal polyps.

Overexpression of glucocorticoid receptor-beta in severe allergic rhinitis

OBJECTIVE

To clarify the role of glucocorticoid receptor-beta in resistance to glucocorticoid therapy for allergic rhinitis, we studied 37 tissue samples from 20 patients with severe allergic rhinitis, and samples from age-matched controls.

METHODS

Patients were treated with intranasal fluticasone for 6 months and inferior turbinectomy was performed for patients with poor response to glucocorticoid treatment. The expression of glucocorticoid receptor-alpha (GR-alpha), glucocorticoid receptor-beta (GR-beta), and nuclear factor-kappaB (NF-kappaB) in nasal mucosa was studied immunohistochemically.

RESULTS

GR-alpha and NF-kappaB were expressed to a similar extent in patients and controls, but GR-beta was expressed significantly more in patients, resulting in an increased GR-beta/GR-alpha ratio.

CONCLUSION

Our findings suggest that GR-beta plays an important role in resistance to glucocorticoid therapy for allergic rhinitis, and its expression might be used as an additional parameter indicating steroid resistance in allergic rhinitis.

Mechanism of action of glucocorticoids in nasal polyposis

Glucocorticoids (GC) are the drugs of choice for the clinical treatment of nasal polyposis, according to the medical literature. Its mechanism of action in the regression of clinical symptoms and polyps, however, is not fully understood. The topical and/or systemic use of glucocorticoids lead to variable expression of cytokines, chemokines and lymphokines, as well as changes in cells. It is known that GC suppresses the expression of pro-inflammatory cytokines, chemokines and adhesion molecules such as ICAM-1 and E-selectin; GC also stimulate the transcription of anti-inflammatory cytokines such as TGF-b. GC suppress pro-fibrotic cytokines related to polyp growth, such as IL-11, the basic fibroblast growth factor (b-FGF), and the vascular endotelial growth factor (VEGF). The action of GC depends fundamentally on their interaction with receptors (GR); certain subjects have a degree of resistance to its effect, which appears to be related with the presence of a b isoform of GR. GC also act variably on the genes involved in immunoglobulin production, presentation, and antigen processing.

AIM

We present a review of the literature on the mechanisms of GC action in nasal polyosis.

CONCLUSION

Understanding the mechanism of action of GC in nasal polyposis will aid in the development of new, more efficient, drugs.

Apoptosis, airway inflammation and anti-asthma therapy: from immunobiology to clinical application

T lymphocyte apoptosis is essential for maintaining immune system homeostasis. Experimental evidence suggests apoptosis control mechanisms may be impaired in inflammatory conditions, particularly airway Th2-type allergic diseases. This review briefly examines the mucosal immune system homeostasis and common apoptotic pathways and discusses impaired apoptosis, allergy, airway inflammation, remodelling and fibrosis. Finally, the paper presents an update on pharmacological targeting of apoptosis to control airway inflammation in patients with allergic asthma.

Topical furosemide versus oral steroid in preoperative management of nasal polyposis

The efficacy of topical nasal furosemide treatment has been shown in the protection of nasal polyp recurrence. The aim of the study was to compare the effect of oral steroid, as standard preoperative treatment, and inhaled furosemide, as alternative treatment, for 7 days preoperatively in terms of subjective improvement of nasal symptoms, polyp size reduction, inflammation in the polyp tissue, and intraoperative blood loss. A group of 40 patients with nasal polyposis entered the study and they were randomly allocated to 7-day preoperative treatment with either oral methylprednisolon (1 mg/kg/day) or topical furosemide by inhalation (6.6 mmol/l solution). Subjective scores of rhinosinusitis symptoms, polyp scores at endoscopy, and biopsy of the most superficial polyp were taken at inclusion. All procedures were repeated on day 7. Intraoperative blood loss was estimated (scores 0-10) by the surgeon at the operation. Eosinophils, mastocytes, and oedema were quantified by histomorphometry. Subjective symptoms and endoscopy scores did not differ significantly between the groups after the treatment although improvement of olfaction was insignificantly better in the steroid group. Steroid treatment significantly reduced eosinophil count, with no effect on mastocytes and oedema. Furosemide treatment did not affect inflammatory cells count significantly, but it has significantly reduced oedema in previously unoperated patients. No difference in intraoperative bleeding was observed between the groups.

Ultrastructural investigation of epithelial damage in asthmatic and non-asthmatic nasal polyps

Nasal polyposis is a poorly understood chronic inflammatory disease often associated with asthma. As nasal polyps and asthma both are associated with massive eosinophil infiltration, they may share a common pathophysiological mechanism. Many genetic and autoimmune diseases may result from altered expression or function of cell adhesion molecules such as desmosomes. A transmission electron microscopical study was carried out on tissue from 15 patients suffering from nasal polyps, to investigate if there are changes in desmosomes in nasal polyps from asthmatic and/or allergic patients versus non-asthmatic versus non-allergic patients. In allergic patients the damage to columnar cells was more extensive than in non-allergic patients. Massive infiltration of eosinophils was observed in epithelium and connective tissue in all groups. No significant difference in thickness of the basal lamina was found between any of the groups. All patients had dilated capillaries in the connective tissue. The intercellular space between the epithelial cells was smallest in the asthmatic non-allergic group. The relative length of columnar cell or basal cell desmosomes was reduced in patients with asthma or allergy, compared to non-allergic, non-asthmatic patients. Hence, there appears to be a weakness in the desmosomes in asthmatics and allergics. Epithelial shedding may play an important role in the pathophysiological process of a multifactorial disease such as asthma.

The role of the eosinophil in nasal diseases

PURPOSE OF REVIEW

The eosinophil is involved in physiologic and pathologic processes, such as asthma, parasitic diseases, granulomatous disorders, fibrosis, malignant tumors and several sino-nasal diseases.

RECENT DEVELOPMENTS

Recent data on the structure and function of the eosinophil provides additional information regarding the pathophysiology and the treatment options of these diseases. In this paper the most recently acquired data on the role of the eosinophil in allergic rhinitis (with or without bronchial asthma), chronic sinusitis (with or without nasal polyposis) and allergic fungal sinusitis are reviewed.

SUMMARY

The data provides evidence regarding the pivotal role of the eosinophil in sino-nasal diseases. Possible ways to target the eosinophils are discussed.

Pathophysiological effects of glucocorticoids on nasal polyps: an update

PURPOSE OF REVIEW

The exact mechanisms by which glucocorticoids exert their beneficial effects on nasal polyps are not clearly defined. Nasal polyps, asthma and allergic rhinitis share common features such as mucosal infiltration with eosinophils and mast cells as well as local IgE production. The present review is an update on the pathophysiological mechanisms of glucocorticoids on nasal polyps described during the last 2 years.

RECENT FINDINGS

The reduction of leukocyte numbers in nasal polyps following glucocorticoid treatment depends on several mechanisms, for example altered balance between the two isoforms of the human glucocorticoid receptors, GRalpha and GRbeta. Another explanation may be inhibition of CD4+ T by CD8+ T cells. Increased expression of the antiinflammatory cytokine transforming growth factor beta may contribute to this. A DNA microarray study which examined the expression of some 22 000 genes showed increased expression of several antiinflammatory genes in nasal polyps after treatment with glucocorticoids. The antiinflammatory gene that increased most was uteroglobin (also known as Clara cell protein 16) which is abundantly expressed in airway secretions and thought to have an important role in regulating inflammation.

SUMMARY

Glucocorticoids affect both pro and antiinflammatory pathways in nasal polyps. Upregulation of antiinflammatory genes such as transforming growth factor beta and uteroglobin may play an important role. Elucidation of these mechanisms may help us to understand not only the effects of glucocorticoids on nasal polyps, but also on related disorders such as allergic rhinitis and asthma.