Prostaglandin, leukotriene, and lipoxin balance in chronic rhinosinusitis with and without nasal polyposis

Interleukin-4 in the Generation of the AERD Phenotype: Implications for Molecular Mechanisms Driving Therapeutic Benefit of Aspirin Desensitization

Aspirin-exacerbated respiratory disease (AERD) is explained in part by over-expression of 5-lipoxygenase, leukotriene C4 synthase (LTC₄S) and the cysteinyl leukotriene (CysLT) receptors (CysLT1 and 2), resulting in constitutive over-production of CysLTs and the hyperresponsiveness to CysLTs that occurs with aspirin ingestion. Increased levels of IL-4 have been found in the sinus mucosa and nasal polyps of AERD subjects. Previous studies demonstrated that IL-4 is primarily responsible for the upregulation of LTC4S by mast cells and the upregulation of CysLT1 and 2 receptors on many immune cell types. Prostaglandin E₂ (PGE₂) acts to prevent CysLT secretion by inhibiting mast cell and eosinophil activation. PGE₂ concentrations are reduced in AERD reflecting diminished expression of cyclooxygenase (COX)-2. IL-4 can inhibit basal and stimulated expression of COX-2 and microsomal PGE synthase 1 leading to decreased capacity for PGE₂ secretion. Thus, IL-4 plays an important pathogenic role in generating the phenotype of AERD. This review will examine the evidence supporting this hypothesis and describe a model of how aspirin desensitization provides therapeutic benefit for AERD patients.

Nonallergic rhinitis and its association with smoking and lower airway disease: A general population study

BACKGROUND

The cause of nonallergic rhinitis (NAR) and its relation to lower airway disease remains unclear. The purpose of this study was to perform a descriptive analysis of the occurrence of rhinitis in a Danish general population with focus on NAR and its association with smoking and lower airway disease.

METHODS

A population-based, cross-sectional study conducted in Copenhagen, Denmark was performed. A random sample from the general population (n = 7931; age, 18-69 years) was invited to a general health examination including measurements of serum-specific immunoglobulin E (IgE) to common aeroallergens; 3471 (44%) persons were accepted. For further analysis, we divided the population into the following groups: (I) negative specific IgE and no rhinitis (controls); (II) negative specific IgE and rhinitis (NAR); (III) positive specific IgE and rhinitis (allergic rhinitis [AR]); and (IV) positive specific IgE but no rhinitis (sensitized).

RESULTS

We found that NAR was associated with asthma (odds ratio [OR] = 2.51 [1.87-3.37]); chronic bronchitis (OR = 2.27 [1.85-2.79]); current smoking (>15 g/day; OR = 1.57 [1.18-2.08]); lower forced expiratory volume in 1 second/forced vital capacity (FEV(1)/FVC) ratios and reduced FEV(1) values. The association with chronic bronchitis was stronger in NAR than in AR, whereas the opposite was true for asthma. FEV(1)/FVC of <70% was not significantly associated to any group.

CONCLUSION

This epidemiological study indicates that both asthma and chronic bronchitis are important comorbidities in NAR confirming the "united airway" hypothesis, and that smoking might be a significant modulator of disease. Although NAR was significantly associated with poor lung function, no significant association with chronic obstructive pulmonary disease was shown.

Expression of arachidonate metabolism enzymes and receptors in nasal polyps of aspirin-hypersensitive asthmatics

BACKGROUND

The pathogenesis of rhinosinusitis in aspirin-exacerbated airway disease is closely linked to the disequilibrium in arachidonic acid metabolism. Although considerable amounts of data concerning impaired eicosanoid production are available, the precise mechanism and pathogenesis of the disease are still unknown. The aim of the present study was to assess the expression of enzymes belonging to the arachidonic acid cascade and receptors for arachidonate derivative metabolites in nasal polyps from aspirin- hypersensitive (AH) and aspirin-tolerant (AT) patients with rhinosinusitis.

METHODS

Cells expressing cysteinyl leukotriene (CysLT) receptors (CysLT(1) and CysLT(2)), arachidonate 5-lipoxygenase, leukotriene B(4) receptor type 1, E-prostanoid receptors (EP(2) and EP(4)), cyclooxygenase (COX)-1 and COX-2 were detected by immunocytochemistry in nasal polyps obtained from 10 AH patients and 18 AT patients.

RESULTS

There was a significantly higher density of cells expressing CysLT(1) and CysLT(2) receptors in nasal polyps from AH patients than from AT patients (p < 0.001). In contrast, the density of cells expressing EP(2) receptor and COX-2 was significantly lower in AH patients than in AT patients (p < 0.02). The number of COX-2-positive epithelial cells was significantly reduced in AH polyps (p < 0.04).

CONCLUSIONS

The elevated number of nasal polyp cells expressing CysLT receptors and lack of cells expressing EP(2) receptor and COX-2 may be related to a more severe course of hyperplastic rhinosinusitis in aspirin hypersensitivity.

Interleukin-13, but not indomethacin, increases cysteinyl-leukotriene synthesis in human lung macrophages

Aspirin-exacerbated respiratory disease (AERD) is associated with constitutively elevated synthesis of bronchoconstrictor cysteinyl-leukotrienes, associated with increased expression of leukotriene (LT)C(4) synthase and Th2 cytokines and airway eosinophilia. We examined whether interleukin-13 can increase LTC(4) synthase gene transcription and cysteinyl-leukotriene synthesis in macrophages isolated from resected human lung tissue and whether an NSAID (indomethacin) can trigger further cysteinyl-leukotriene synthesis in these cells. Overnight culture of human lung macrophages with IL-13 (10 ng/mL) increased spontaneous and ionophore-stimulated production of cysteinyl-leukotrienes by 42% (P = 0.02) and 52% (P = 0.005), respectively, as quantified by enzyme immunoassays, but PCR gene transcription assays did not demonstrate an effect on LTC4S mRNA. The addition of indomethacin (100 μM) did not modulate cysteinyl-leukotriene production in either IL-13-treated or untreated macrophages. We conclude that while IL-13 enhances cysteinyl-leukotriene synthesis in human lung macrophages, it does not replicate the enhanced LTC(4) synthase expression observed in the AERD lung nor confer sensitivity to NSAIDs.

Pathophysiology of Chronic Rhinosinusitis with Nasal Polyp

Background

Chronic rhinosinusitis (CRS) is a common inflammatory condition of the paranasal sinuses and nasal passages. CRS with nasal polyp (CRSwNP) is a subtype of CRS, and the pathogenesis of CRSwNP remains largely unclear.

Methods

This article reviews the literature regarding the pathophysiology of CRSwNP.

Results

Evidence suggests that altered innate immunity, adaptive immunity, tissue remodeling, and/or effects of microorganisms may play a role in the development of CRSwNP. Aberrant arachidonic acid metabolism may also contribute to the pathogenesis of CRSwNP in patients with aspirin-exacerbated respiratory disease.

Conclusion

There have been significant advances in the understanding pathophysiology of CRSwNP. Additional research is needed to elucidate these mechanisms and to determine their relative importance in the pathogenesis of CRSwNP.

Urinary concentrations of 15-epimer of lipoxin A(4) are lower in patients with aspirin-intolerant compared with aspirin-tolerant asthma

BACKGROUND

Although an abnormality in arachidonic acid metabolism may be responsible for aspirin-intolerant asthma (AIA), there is little knowledge about the concentrations of urinary lipoxin A(4) (LXA(4)) and the 15-epimer of LXA(4) (15-epi-LXA(4)) in relation to asthma severity in AIA subjects.

OBJECTIVE

The purpose of this study is to estimate urinary LXA(4) and the 15-epimer concentrations to investigate lipoxins in AIA.

METHODS

In this study, we examined AIA, aspirin-tolerant asthma (ATA) and healthy control groups. The AIA and ATA groups were subdivided into the severe asthma and non-severe asthma subgroups. Urinary LXA(4), 15-epi-LXA(4) and leukotriene E(4) (LTE(4) ) were quantified using enzyme immunoassay after separating these compounds using high-performance liquid chromatography.

RESULTS

The urinary LXA(4) concentration was significantly lower than the 15-epi-LXA(4) concentration in the asthmatic subjects. The AIA group showed significantly lower urinary 15-epi-LXA(4) (P < 0.01) and higher urinary LTE(4) concentrations (P < 0.05) than the ATA group. Comparison of 15-epi-LXA(4) concentrations between the severe asthmatic and non-severe asthmatic subjects in the AIA and ATA groups revealed that the decreased 15-epi-LXA(4) concentration may be related to aspirin intolerance, but not asthma severity. Receiver operator characteristic curves demonstrated that the concentration ratio of LTE(4) to 15-epi-LXA(4) was superior to 15-epi-LXA(4) concentration and LTE(4) concentration as a predictive factor for aspirin intolerance.

CONCLUSIONS AND CLINICAL RELEVANCE

We have demonstrated for the first time that urinary 15-epi-LXA(4) concentration is significantly higher than LXA(4) concentration in both the AIA and ATA groups. 15-Epi-LXA(4) concentration was significantly lower in the AIA group with an increased urinary LTE(4) concentration than in the ATA group. An imbalance between proinflammatory cysteinyl-leukotrienes and anti-inflammatory 15-epi-LXA(4) may be involved in AIA pathogenesis.

Genetics and phenotyping in chronic sinusitis

Chronic sinusitis with nasal polyposis historically has been treated as a single monolithic clinical disorder. Just as asthma is now accepted as numerous heterogeneous diseases, chronic sinusitis should also be viewed as comprising several diseases with varying causes, with each one characterized by distinct histologic and gene and protein expression patterns. This includes recognition of the need to define these diseases based on the presence or absence of an eosinophilic infiltrate but also on additional distinctions based on unique agents that drive their development and perpetuation. As a collection of heterogeneous diseases, proper differential diagnosis is required to delineate appropriate therapeutic intervention. This review will focus on recognized distinct presentations of chronic sinus disease, including distinguishing the clinical presentations, cellular and molecular characteristics, genetic differences, and current treatment options for each.

Reduced expression of COXs and production of prostaglandin E(2) in patients with nasal polyps with or without aspirin-intolerant asthma

BACKGROUND

Researchers have debated whether regulation of the COX enzymes (COX-1 and COX-2), which mediate production of prostaglandins (PGs), affects the pathogenesis of nasal polyps (NPs) and aspirin-intolerant asthma (AIA).

OBJECTIVE

We investigated the roles of PGE(2), COX-1 and COX-2, and PGE(2) receptors in the development of NPs and AIA by measuring their expression in fibroblasts derived from nasal mucosa (NM) and NPs.

METHODS

Fibroblasts were isolated from the NM of subjects without asthma who had septal deviation, turbinate hypertrophy, or both (control subjects, n = 7); NPs of aspirin-tolerant nonasthmatic patients (n = 7); and NPs of patients with asthma who were intolerant of aspirin (n = 7). Polyp samples were collected during endoscopic surgery. Cultures were stimulated with IL-1β (10 ng/mL) for 72 hours. We used ELISA, immunoblotting, and immunofluorescence analyses to measure secretion of PGE(2), expression of COX-1 and COX-2, and expression of the PGE(2) receptors EP1 to EP4.

RESULTS

Compared with NM from control subjects, PGE(2) concentrations were significantly lower in IL-1β-stimulated fibroblasts from patients with NPs who were tolerant to aspirin and even lower in polyps from patients with AIA. Similarly, IL-1β exposure induced the expression of COX-1 and COX-2 in fibroblasts from NM of control subjects, had only moderate effects on fibroblasts from NPs of aspirin-tolerant nonasthmatic patients, and almost no effect on fibroblasts from NPs of patients with AIA. IL-1β also induced expression of EP2 in fibroblasts from control NM but not in fibroblasts from NPs of aspirin-tolerant nonasthmatic patients or those with AIA.

CONCLUSION

Alterations in the COX pathway (ie, reduced production of PGE(2) and lack of upregulation of COX-1, COX-2, and EP2 under conditions of inflammation) are associated with NPs in patients with or without AIA.

T cell inflammatory response, Foxp3 and TNFRS18-L regulation of peripheral blood mononuclear cells from patients with nasal polyps-asthma after staphylococcal superantigen stimulation

BACKGROUND

Staphylococcal superantigens may modulate airway inflammatory disease.

OBJECTIVE

We assessed the effect of Staphylococcus aureus enterotoxin B (SEB) on T cell activation in patients with nasal polyps and asthma, and its possible link to aspirin hypersensitivity.

METHODS

Leucocytes were isolated from five healthy subjects (controls), five asthmatics with nasal polyps without (NP-ATA) and five with aspirin-induced asthma (NP-AIA). Cells were incubated with increasing concentrations of SEB for 4 and 18 h. Release of T(H)1/T(H)2 cytokines was assessed by Cytometric Bead-Array. Foxp3 and TNFRS18-L expression were analysed by qPCR and flow cytometry.

RESULTS

After 4 and 18 h, SEB significantly increased IFN-gamma, IL-4, TNF-alpha, IL-5 and IL-2 concentrations in supernatants of both NP polyp groups compared with controls. Baseline Foxp3 was significantly decreased in both NP-asthma groups. Incubation with SEB for 4 h induced a limited up-regulation of Foxp3 in NP-AIA patients, which was switched off consecutively. Foxp3 was significantly up-regulated in the control group after 18 h, but not in the NP-asthmatic groups. In parallel, TNFRS18-L mRNA significantly increased after 18 h in the NP-asthma groups compared with control subjects. This molecule was highly expressed in CD11c(+)CD14(+) cells and its levels increased after 18 and 24 h culture in the NP-asthma patients.

CONCLUSION

SEB induces both T(H)1 and T(H)2 pro-inflammatory responses in patients with nasal polyps and asthma regardless of the presence of aspirin hypersensitivity. The nature of this response may be linked to a basal deficiency of Foxp3 observed in the NP-asthmatic patients and/or to the up-regulation of TNFRS18-L on monocytes/dendritic cell precursors.

Role of fungal antigens in eosinophilia-associated cellular responses in nasal polyps: a comparison with enterotoxin

BACKGROUND

Fungi and/or Staphylococcus aureus enterotoxins (SEs) may participate in the pathogenesis of eosinophilic inflammation in cases of chronic rhinosinusitis with nasal polyps (CRSwNP). Objective We sought to determine the effects of fungal antigens on eosinophilia-associated cellular responses in nasal polyps.

METHODS

Dispersed nasal polyp cells (DNPCs) were prepared from 13 patients with CRSwNP. DNPCs were cultured with fungal extracts (Aspergillus, Alternaria and Candida) or SEB for 72 h, after which the levels of IL-5, IL-13 and RANTES were measured within the supernatant. Responses to β-d-glucan, mannan and chitin were also examined.

RESULTS

38.5%, 69.2% and 30.8% of DNPCs produced IL-5, IL-13 and RANTES, respectively, in response to 200 μg/mL of Aspergillus. 53.8%, 53.8% and 7.7% of DNPCs produced IL-5, IL-13 and RANTES, respectively, in response to 200 μg/mL of Alternaria. 53.8%, 38.5% and 15.4% of DNPCs produced IL-5, IL-13 and RANTES, respectively, in response to 200 μg/mL of Candida. All DNPCs produced these cytokines in response to 0.1 μg/mL of SEB. SEB induced significantly greater cytokine levels than the fungal extracts. No correlation between cytokine production following exposure to each of the fungal extracts or SEB and various clinical features, including nasal polyp eosinophilia and radiological severity of sinusitis was observed. Neither sensitization to fungus nor comorbidity with bronchial asthma was correlated with the fungal extract-induced cytokine production by DNPCs. β-d-glucan, mannan and chitin did not induce significant cytokine production.

CONCLUSIONS

These results suggest that, although DNPCs produce IL-5, IL-13 and RANTES in response to fungal extracts, fungal antigens including major carbohydrates are less capable of inducing eosinophilia-associated cellular responses in nasal polyps than SEB.

Eosinophilic chronic rhinosinusitis in Japan

Chronic rhinosinusitis is a heterogeneous disease. In Europe and the United States, it has recently been divided into two subgroups: chronic rhinosinusitis with nasal polyps (CRSwNP) and chronic rhinosinusitis without nasal polyps (CRSsNP). The majority of CRSwNP cases have a strong tendency to recur after surgery and show eosinophil-dominant inflammation. However, this definition has proved difficult to apply in Japan and East Asia, because more than half of the CRSwNP cases do not exhibit eosinophil-dominant inflammation in these areas of the world. In Japan in the 1990s, refractory CRSwNP to the standard treatment was focused on in clinical studies and the term "eosinophilic chronic rhinosinusitis" (ECRS) was introduced to identify this subgroup of chronic rhinosinusitis in 2001. ECRS is different from non-ECRS in terms of many clinical features: symptom appearance, occurrence site of nasal polyps, CT scan findings, the histology of nasal polyps, blood examination findings, clinical course after surgery, and co-morbid asthma, etc. In this review, we describe these clinical features and mention how to make a clinical diagnosis of ECRS as well as how to treat it. Finally, we discuss the pathophysiology of ECRS. The concept of ECRS in Japan would be applicable for CRSwNP in other countries including Europe and the United States.

Antileukotrienes in rhinosinusitis and nasal polyposis

Nasal polyposis is a chronic inflammatory disease of the nasal and paranasal sinus mucosa that, despite different hypotheses of its cause, remains poorly understood. The management of nasal polyposis has been the topic of countless frequent controversial debates for many decades. International guidelines generally suggest that first-line treatment should be based on a medical approach with mainly nasal and oral corticosteroids. Surgical procedures are often viewed as adjunctive to medical therapy. Given that antileukotrienes are currently indicated in the treatment of asthma and allergic rhinitis and there exists an increased leukotriene production in nasal polyps, antileukotrienes, especially montelukast, may represent a potential effective therapy for chronic rhinosinusitis, including nasal polyps.

A microarray study of gene expression profiles in nasal polyps

OBJECTIVE

Nasal polyposis (NP) is a multifactorial disease manifesting in chronic inflammation of upper respiratory tract of unknown etiology. We studied mRNA gene expression profiles in NP compared with normal mucosa as well as pointed at genes characteristic of different expression in examined tissues.

MATERIAL AND METHODS

Fifty-three patients with NP (36 eosinophilic and 17 neutrophilic NP) were included into the study. Transcriptional activity of genes was analyzed using oligonucleotide microarray in 17 NP and 8 cases of normal nasal mucosa. A study of mRNA expression of selected genes was performed using QRT-PCR.

RESULTS

We identified 556 genes, which were differentially expressed between the studied and the control group. Among them 217 showed significantly higher expression, whereas 339 lower expression in NP than in controls. The microarray and QRT-PCR results were compatible for 7 of 8 evaluated genes. In NP strongly significant higher transcriptional activity of MMP10, NOS2A, ALOX15 and IL-8 genes was observed. In the control group, significantly higher expression of DMBT1, ALOX12 and LTF genes was detected.

CONCLUSION

The analysis of gene expression in inflammatory changed nasal polyp tissues may become a supplementary method in diagnostics and treatment. Molecular alterations may indicate changes during the clinical course of the disease.

Montelukast in the treatment of asthma as a systemic disease

Asthma affects 300 million people worldwide. The common association of asthma with allergic rhinitis and the presence of proinflammatory mediators in the circulation of patients provide strong evidence for the need to treat asthma as a systemic disease. The leukotriene receptor antagonist montelukast is a disease-specific oral medication that has dual effects on airway smooth muscle cells and inflammatory processes. This review describes recent randomized, controlled studies of montelukast in asthma and allergic rhinitis in adults and children as young as 3 months old. Montelukast treatment consistently produced significant reductions in asthma exacerbations. While many patients may benefit from montelukast as monotheray, combination treatment for chronic asthma with inhaled corticosteroids is advocated as being rational. Significant improvements in symptoms and quality of life were observed in allergic rhinitis patients. Montelukast is well tolerated in patients of all ages. Long-term studies are underway to determine its effects on airway remodeling.

Partial characterization of normal and Haemophilus influenzae-infected mucosal complementary DNA libraries in chinchilla middle ear mucosa

OBJECTIVES

We sought to construct and partially characterize complementary DNA (cDNA) libraries prepared from the middle ear mucosa (MEM) of chinchillas to better understand pathogenic aspects of infection and inflammation, particularly with respect to leukotriene biogenesis and response.

METHODS

Chinchilla MEM was harvested from controls and after middle ear inoculation with nontypeable Haemophilus influenzae. RNA was extracted to generate cDNA libraries. Randomly selected clones were subjected to sequence analysis to characterize the libraries and to provide DNA sequence for phylogenetic analyses. Reverse transcription-polymerase chain reaction of the RNA pools was used to generate cDNA sequences corresponding to genes associated with leukotriene biosynthesis and metabolism.

RESULTS

Sequence analysis of 921 randomly selected clones from the uninfected MEM cDNA library produced approximately 250,000 nucleotides of almost entirely novel sequence data. Searches of the GenBank database with the Basic Local Alignment Search Tool provided for identification of 515 unique genes expressed in the MEM and not previously described in chinchillas. In almost all cases, the chinchilla cDNA sequences displayed much greater homology to human or other primate genes than with rodent species. Genes associated with leukotriene metabolism were present in both normal and infected MEM.

CONCLUSIONS

Based on both phylogenetic comparisons and gene expression similarities with humans, chinchilla MEM appears to be an excellent model for the study of middle ear inflammation and infection. The higher degree of sequence similarity between chinchillas and humans compared to chinchillas and rodents was unexpected. The cDNA libraries from normal and infected chinchilla MEM will serve as useful molecular tools in the study of otitis media and should yield important information with respect to middle ear pathogenesis.

Profile of eicosanoid generation in aspirin-intolerant asthma and anaphylaxis assessed by new biomarkers

BACKGROUND

It has recently demonstrated that a free radical-mediated pathway generates prostaglandins (PGs) and the corresponding prostaglandin enantiomers (ent-PGs). Aspirin-intolerant asthma and anaphylaxis accompany PGD(2) overproduction, possibly associated with mast cell activation via the COX pathway. However, free radical-mediated PG generation in the pathophysiology of these diseases, which can be demonstrated by measuring urinary ent-PGF(2)alpha, has not been reported.

OBJECTIVES

To evaluate the characteristic profile of eicosanoid generation via the COX and/or free radical-mediated pathway underlying aspirin-intolerant asthma and anaphylaxis.

METHODS

A comparative group analysis consisted of asthma (n = 17) and anaphylaxis (n = 8, none with aspirin-induced anaphylaxis) cases. Urinary eicosanoid concentrations were quantified as follows: 2,3-dinor-9alpha,11beta-PGF(2) by gas chromatography-mass spectrometry; leukotriene E(4), 9alpha,11beta-PGF(2), and PGs by enzyme immunoassay.

RESULTS

2,3-Dinor-9alpha,11beta-PGF(2) is a more predominant PGD(2) metabolite in urine than 9alpha,11beta-PGF(2). At baseline, the aspirin-intolerant asthma group (n = 10) had significantly higher leukotriene E(4) and lower PGE(2) concentrations in urine than the aspirin-tolerant asthma group. During the reaction, the urinary concentrations of leukotriene E(4) and PGD(2) metabolites correlatively increased, but with markedly different patterns of the mediator release, in the aspirin-intolerant asthma group and the anaphylaxis group, respectively. The urinary PGD(2) metabolites and primary PGs were significantly decreased in the aspirin-tolerant asthma group. Urinary ent-PGF(2)alpha concentrations were significantly increased in the anaphylaxis group but not the aspirin-intolerant asthma group.

CONCLUSIONS

When assessed by urinary 2,3-dinor-9alpha,11beta-PGF(2), PGD(2) overproduction during aspirin-intolerant bronchoconstriction was clearly identified, regardless of COX inhibition. It is evident that free radical-mediated PG generation is involved in the pathophysiology of anaphylaxis.

Aspirin-sensitive respiratory disease

Aspirin-sensitive respiratory disease (ASRD) is a condition characterized by persistent and often severe inflammation of the upper and lower respiratory tracts. Patients develop chronic eosinophilic rhinosinusitis, nasal polyposis, and asthma. The ingestion of aspirin and other cyclooxygenase-1 (COX-1) inhibitors induces exacerbations of airway disease that may be life-threatening. Thus, aspirin sensitivity is a phenotypic marker for the syndrome, yet nearly all affected individuals can be desensitized by the administration of graded doses of aspirin, leading to long-term clinical benefits. Patients with aspirin sensitivity are often able to tolerate selective COX-2 inhibitors. The pathogenesis of ASRD is underpinned by abnormalities in eicosanoid biosynthesis and eicosanoid receptor expression coupled with intense mast cell and eosinophilic infiltration of the entire respiratory tract. This review focuses on the molecular, cellular, and biochemical abnormalities characterizing ASRD and highlights unanswered questions in the literature and potential future areas of investigation.

Modulation by aspirin of nuclear phospho-signal transducer and activator of transcription 6 expression: Possible role in therapeutic benefit associated with aspirin desensitization

BACKGROUND

Aspirin-exacerbated respiratory disease is characterized by asthma, nasal polyps, and intolerance to aspirin with overexpression of leukotriene (LT) C(4) synthase and cysteinyl leukotriene receptors. Through an unknown mechanism, aspirin desensitization is an effective treatment.

OBJECTIVE

We hypothesized that aspirin desensitization blocks IL-4-induced expression of these LT activities through inhibition of signal transducer and activator of transcription 6 (STAT6)-mediated transcription.

METHODS

Nuclear extracts were derived from THP-1 and normal human monocytes resting and cocultured with aspirin before IL-4 stimulation. Quantitative PCRs were conducted. Electrophoretic mobility shift assays were performed by using oligomers for STAT6 sites within the LT receptor and synthase promoters. Western blots of nuclear extracts were probed by using anti-phospho-STAT6 antibodies.

RESULTS

Upregulation of LT receptor mRNA by IL-4 was negated by aspirin and ketorolac but not by sodium salicylate. The STAT6 site in the LT receptor and synthase promoters was confirmed by using mobility shift assays by competing with unlabeled STAT6 consensus probes and supershifts with anti-STAT6 antibodies. Aspirin and ketorolac decreased the IL-4-inducible expression of nuclear STAT6 observed in mobility shift assays and Western hybridization.

CONCLUSION

The LT receptor and synthase promoters have STAT6-binding sites that are engaged by IL-4-induced nuclear extracts and inhibited by aspirin. Assuming that normal monocytes behave like monocytes from patients with aspirin-exacerbated respiratory disease, inhibition of IL-4-STAT6 might explain a mechanism in aspirin desensitization daily treatment, resulting in downregulation of production and responsiveness to cysteinyl leukotrienes. This biologic activity of aspirin likely reflects COX inhibition because it was shared with ketorolac but not sodium salicylate.

Nasal mucosal expression of the leukotriene and prostanoid pathways in seasonal and perennial allergic rhinitis

BACKGROUND

Leukotrienes (LTs) and prostanoids are potent pro-inflammatory and vasoactive lipid mediators implicated in airway disease, but their cellular sources in the nasal airway in naturally occurring allergic rhinitis (AR) are unclear.

OBJECTIVE

To quantify cellular expression of enzymes of the 5-lipoxygenase (5-LO) and cyclooxygenase (COX) pathways by immunohistochemistry in nasal biopsies from patients with symptomatic perennial AR (PAR, n = 13) and seasonal AR (SAR, n = 14) and from normal subjects (n = 12).

METHODS

Enzymes of the 5-LO pathway (5-LO, FLAP, LT A4 hydrolase, LTC4 synthase) and the COX pathway (COX-1, COX-2, prostaglandin D2 synthase) were immunostained in glycol methacrylate resin-embedded inferior turbinate biopsy specimens, quantified in the lamina propria and epithelium, and co-localized to leucocyte markers by camera lucida.

RESULTS

In the lamina propria of PAR biopsies, median counts of cells expressing FLAP were fourfold higher than in normal biopsies (Mann-Whitney, P = 0.014), and also tended to be higher than in SAR biopsies (P = 0.06), which were not different from normal. PAR biopsies showed threefold more cells immunostaining for LTC4 synthase compared with SAR biopsies (P = 0.011) but this was not significant compared with normal biopsies (P = 0.2). These changes were associated with ninefold more eosinophils (P = 0.0005) with no differences in other leucocytes. There were no significant differences in the lamina propria in immunostaining for 5-LO, LTA4 hydrolase, COX-1, COX-2 or PGD2 synthase. Within the epithelium, increased expression of COX-1 was evident in PAR biopsies (P = 0.014) and SAR biopsies (P = 0.037), associated with more intra-epithelial mast cells in both rhinitic groups (P < 0.02).

CONCLUSIONS

In the nasal biopsies of PAR subjects, increased expression of regulatory enzymes of the cysteinyl-LT biosynthetic pathway was associated with lamina propria infiltration by eosinophils. Seasonal rhinitis biopsies shared only some of these changes, consistent with transient disease. Increased intra-epithelial mast cells and epithelial COX-1 expression in both rhinitic groups may generate modulatory prostanoids.

Important research questions in allergy and related diseases: 3-chronic rhinosinusitis and nasal polyposis - a GALEN study

Chronic rhinosinusitis is one of the most common health care challenges, with significant direct medical costs and severe impact on lower airway disease and general health outcomes. The diagnosis of chronic rhinosinusitis (CRS) currently is based on clinical signs, nasal endoscopy and CT scanning, and therapeutic recommendations are focussing on 2 classes of drugs, corticosteroids and antibiotics. A better understanding of the pathogenesis and the factors amplifying mucosal inflammation therefore seems to be crucial for the development of new diagnostic and therapeutic tools. In an effort to extend knowledge in this area, the WP 2.7.2 of the GA(2)LEN network of excellence currently collects data and samples of 1000 CRS patients and 250 control subjects. The main objective of this project is to characterize patients with upper airway disease on the basis of clinical parameters, infectious agents, inflammatory mechanisms and remodeling processes. This collaborative research will result in better knowledge on patient phenotypes, pathomechanisms, and subtypes in chronic rhinosinusitis. This review summarizes the state of the art on chronic rhinosinusitis and nasal polyposis in different aspects of the disease. It defines potential gaps in the current research, and points to future research perspectives and targets.

Involvement of mitogen-activated protein kinases and nuclear factor kappa B pathways in signaling COX-2 expression in chronic rhinosinusitis

OBJECTIVE

To investigate the signal pathways involved in cyclooxygenase-2 (COX-2) expression in chronic rhinosinusitis (CRS).

METHODS

The expressions of COX-2, p38 mitogen-activated protein kinase (p38MAPK), extracellular signal-regulated kinase (ERK), and nuclear factor kappa B (NF-kappaB) in nasal mucosa were detected by immunohistological stain and polymerase chain reaction (PCR). Their expressions and prostaglandin E2 (PGE(2)) release were determined by PCR, Western blot and enzyme immunoassay (EIA) in human nasal epithelia (HNE) cells after lipopolysaccharide (LPS) induction, and/or small interfering RNA (siRNA) transfection.

RESULTS

Positive protein expressions of COX-2, p38MAPK, ERK, NF-kappaB subunits were detected in epithelial and inflammatory cells. Their mRNA levels were significantly higher in CRS than controls (P < 0.05). The expressions varied in time and concentration-dependent manner in LPS-induced HNE cells. COX-2 expression was suppressed by siRNAs of P38MAPK, ERK, and NF-kappaB; however, COX-2-specific siRNA had no blocking effect on them. SiRNAs of P38MAPK or ERK could block NF-kappaB, but NF-kappaB-specific siRNA had no blocking effect on the former. SiRNA of p38MAPK, or ERK did not inhibit each other.

CONCLUSION

Upregulation of COX-2 expression suggested its role as a mediator in CRS. ERK and p38MAPK pathways were involved in signaling COX-2 through NF-kappaB pathway.

Prostaglandin E(2) suppresses staphylococcal enterotoxin-induced eosinophilia-associated cellular responses dominantly through an E-prostanoid 2-mediated pathway in nasal polyps

BACKGROUND

Recent investigations have revealed that staphylococcal enterotoxins (SEs), COX metabolism, or both might participate in the pathogenesis of eosinophilic airway diseases, such as chronic rhinosinusitis with nasal polyposis.

OBJECTIVE

We sought to determine whether COX metabolism, especially prostaglandin (PG) E(2), plays a significant role in SE-induced cellular responses in nasal polyps.

METHODS

Dispersed nasal polyp cells (DNPCs) were prepared from nasal polyps by means of enzymatic digestion. DNPCs were cultured with SEB in the presence or absence of COX inhibitors (diclofenac and indomethacin) for 72 hours; then the levels of IL-5, IL-13, RANTES, and eotaxin in the supernatants were measured. The effect of PGE(2) on SEB-induced responses by diclofenac-treated DNPCs was examined, especially in terms of receptor specificity.

RESULTS

DNPCs produced significant amounts of IL-5, IL-13, and RANTES in response to SEB. COX inhibitors significantly increased the production of these cytokines. The degree of local eosinophilia was significantly and positively correlated with the changes in IL-5 production induced by diclofenac treatment. PGE(2) significantly and dose-dependently inhibited SEB-induced IL-5, IL-13, and RANTES production by diclofenac-treated DNPCs. E-prostanoid (EP) 2 receptor-selective agonist strongly inhibited the production of all 3 cytokines. EP3 and EP4 receptor-selective agonists partially suppressed these responses, whereas EP1 receptor-selective agonist did not. Interestingly, all of the combined treatments with 2 of the 4 EP receptor-selective agonists significantly inhibited the SEB-induced responses by diclofenac-treated DNPCs.

CONCLUSIONS

These results suggest that PGE(2) inhibits the pathogenesis of SEB-induced eosinophilic inflammation primarily through the EP2-mediated pathway in patients with chronic rhinosinusitis with nasal polyposis.

Chemokine CC-ligand 5 production and eosinophil activation into the upper airways of aspirin-sensitive patients

BACKGROUND

Airway eosinophilia is a hallmark of aspirin-sensitive asthma/rhinitis.

OBJECTIVE

We have investigated chemokine CC-ligand 5 (CCL5) production and its association with eosinophil activation in the upper airways of aspirin-sensitive patients both in vivo and in vitro.

METHODS

Twenty aspirin-sensitive asthma/rhinosinusitis patients, 18 atopic-tolerant asthma/rhinosinusitis patients and 15 healthy control subjects took part in the study. All subjects were challenged with saline and lysine-acetylsalicylic acid (L-asa) on separate occasions. Nasal lavages were obtained at baseline and 120 min after challenge and analysed for mediators' release.

RESULTS

When compared with control subjects, the baseline levels of CCL5 were significantly increased in both sensitive and tolerant patients (there was no significant difference in CCL5 concentrations between these two groups, P>0.05). However, L-asa nasal challenge induced significantly increased levels of CCL5 in the sensitive patients but not in the tolerant subjects (median: 380 vs. 140 pg/mL, P<0.0001). Similarly, the concentrations of both eosinophil cationic protein (ECP) and cysteinil leukotriene (cys-LTs) were increased significantly in the aspirin-sensitive but not in the tolerant patients. There was a trend towards a significant correlation between CCL5 and ECP concentrations in the sensitive patients following L-ASA challenge. On incubation with aspirin, nasal tissue derived from aspirin-sensitive but not that derived from tolerant subjects released increased CCL5 levels in culture. As determined by immunohistochemistry, CCL5 was predominantly localized to the nasal airway epithelium.

CONCLUSION

Altogether, these findings suggest that CCL5 is released in aspirin-sensitive asthma/rhinosinusitis.

Correlation between the prostaglandin D(2)/E(2) ratio in nasal polyps and the recalcitrant pathophysiology of chronic rhinosinusitis associated with bronchial asthma

BACKGROUND

The prevalence of patients with chronic rhinosinusitis (CRS) refractory to traditional therapy appears to be on the increase. In these cases, CRS tends to be associated with bronchial asthma (BA), especially, aspirin-intolerant asthma (AIA). On the other hand, arachidonic acid metabolites have been extensively investigated in the pathogenesis of BA. We sought to assess the role of prostaglandin D(2) (PGD(2)) and prostaglandin E(2) (PGE(2)) in the recalcitrant pathophysiology of CRS.

METHODS

Samples were prepared from the nasal polyps and mucosa of 40 patients undergoing endoscopic sinus surgery (ESS) at our hospital. The nasal polyp specimens obtained from the patients with CRS were divided into three groups, as follows: the CRS-AIA group, consisting of specimens obtained from patients with CRS complicated by AIA, the CRS-ATA group, consisting of specimens obtained from patients with CRS associated with aspirin-tolerant asthma (ATA), and the CRS-NA group, consisting of specimens obtained from CRS patients without BA. PGD(2) and PGE(2) were extracted from the specimens and quantified.

RESULTS

The concentrations of PGD(2) were significantly higher in the nasal polyps of the CRS-ATA group. The concentrations of PGE(2) were lowest in the nasal polyps of the CRS-AIA group. The PGD(2)/PGE(2) ratio was highest in the CRS-AIA group.

CONCLUSIONS

It has previously been reported that CRS complicated by AIA is most likely to be characterized by repeated remissions and relapses, and is thus the most intractable. We may therefore say that the PGD(2)/PGE(2) ratio reflects the intractable nature of CRS.

Hyperleukotrieneuria in patients with allergic and inflammatory disease

Cysteinyl leukotrienes (CysLTs: leukotrienes C(4), D(4), and E(4)) have long been implicated in the pathogenesis of asthma and several allergic diseases. LTE(4) has been identified as a major metabolite of LTC(4), and urinary LTE(4) (U-LTE(4)) is considered as the most reliable analytic parameter for monitoring the endogenous synthesis of CysLTs. From recent studies on the U-LTE(4) associated with adult stable asthma we identified four factors for hyperleukotrieneuria, namely, aspirin intolerance, eosinophilic nasal polyposis (ENP), vasculitis, and severe asthma. In ENP, there is prominent infiltration of eosinophils in the sinus and polyp tissues, which is linked to adult asthma and aspirin sensitivity, and ENP is the most important factor for the overproduction of CysLTs in asthmatics. We also demonstrated that anaphylaxis and eosinophilic pneumonia (EP) are associated with a marked increase in the U-LTE(4) concentration. Under these disease conditions, U-LTE(4) may be one of the candidate biomarkers. Moreover, the changes in U-LTE(4) concentrations may provide valuable information concerning therapeutic targets.

An intranasal selective antisense oligonucleotide impairs lung cyclooxygenase-2 production and improves inflammation, but worsens airway function, in house dust mite sensitive mice

Background

Despite its reported pro-inflammatory activity, cyclooxygenase (COX)-2 has been proposed to play a protective role in asthma. Accordingly, COX-2 might be down-regulated in the airway cells of asthmatics. This, together with results of experiments to assess the impact of COX-2 blockade in ovalbumin (OVA)-sensitized mice in vivo, led us to propose a novel experimental approach using house dust mite (HDM)-sensitized mice in which we mimicked altered regulation of COX-2.

Methods

Allergic inflammation was induced in BALBc mice by intranasal exposure to HDM for 10 consecutive days. This model reproduces spontaneous exposure to aeroallergens by asthmatic patients. In order to impair, but not fully block, COX-2 production in the airways, some of the animals received an intranasal antisense oligonucleotide. Lung COX-2 expression and activity were measured along with bronchovascular inflammation, airway reactivity, and prostaglandin production.

Results

We observed impaired COX-2 mRNA and protein expression in the lung tissue of selective oligonucleotide-treated sensitized mice. This was accompanied by diminished production of mPGE synthase and PGE₂ in the airways. In sensitized mice, the oligonucleotide induced increased airway hyperreactivity (AHR) to methacholine, but a substantially reduced bronchovascular inflammation. Finally, mRNA levels of hPGD synthase remained unchanged.

Conclusion

Intranasal antisense therapy against COX-2 in vivo mimicked the reported impairment of COX-2 regulation in the airway cells of asthmatic patients. This strategy revealed an unexpected novel dual effect: inflammation was improved but AHR worsened. This approach will provide insights into the differential regulation of inflammation and lung function in asthma, and will help identify pharmacological targets within the COX-2/PG system.

Asthma: a syndrome composed of heterogeneous diseases

OBJECTIVE

To review the concept that asthma comprises distinct heterogeneous inflammatory disorders characterized by patients showing different phenotypes with distinct genetic components, environmental causes, and immunopathologic signa-

DATA SOURCES

Ovid MEDLINE and PubMed databases from 1950 to the present time were searched for relevant articles and references regarding the heterogeneity of asthma.

STUDY SELECTION

Articles that described the various phenotypes of asthma were used for this review.

RESULTS

Asthma is unlikely to be a single disease but rather a series of complex, overlapping individual diseases or phenotypes, each defined by its unique interaction between genetic and environmental factors. These conditions include syndromes characterized by allergen-exacerbated, nonallergic, and aspirin-exacerbated factors along with syndromes best distinguished by their pathologic findings (eosinophilic, neutrophilic, pauci-granulocytic), response to therapy (corticosteroid resistant), and natural history (remodeling prone). Additional phenotypes will almost certainly be identified as advances in genetics and other profiling methods are made and will be accompanied by the availability of clear biomarkers for distinguishing among them.

CONCLUSIONS

Responses to asthma medications vary considerably among patients, likely reflecting, at least in part, the differing sensitivities of the various asthma phenotypes. Selecting the best possible treatment course in individual patients will be aided by clearly identifying the different phenotypes. Physicians need to recognize this when making decisions to adjust treatment to improve asthma control.

Cyclooxygenases and the pathogenesis of chronic rhinosinusitis and nasal polyposis

Cyclooxygenase (COX) enzymes catalyze the rate-limiting steps in prostaglandin synthesis. Prostaglandins have an important role in several physiological processes such as maintenance of gastrointestinal integrity and pathological processes such as inflammation and neoplasia. Several mechanisms have been proposed for the development of chronic rhinosinusitis, but the common final pathway seems to be an integrated process involving the mucosal epithelium, matrix, and inflammatory cells and mediators. Upper and lower airway pathologies coexist and share common etiopathogenic mechanisms, and nasal polyposis is often associated with asthma and aspirin sensitivity. The cellular source of COX activity in acute and chronic inflammation, as in chronic rhinosinusitis, is poorly understood. COX theory postulated that inhibition of COX broke down biochemical reactions that lead to the development of asthma attacks. This article focuses on COX in the pathogenesis of chronic rhinosinusitis and nasal polyposis.

Role of staphylococcal superantigens in upper airway disease

PURPOSE OF REVIEW

Chronic rhinosinusitis with nasal polyps often represents a chronic severe inflammatory disease of the upper airways and may serve as a model for lower airway diseases such as late-onset intrinsic asthma. Enterotoxins derived from Staphylococcus aureus have been implicated in the pathophysiology of nasal polyps as disease-modifying factors; recent findings using therapeutic proof-of-concept approaches support this hypothesis.

RECENT FINDINGS

Nasal polyps (chronic rhinosinusitis with nasal polyps) are characterized by a T-helper-2 dominated cytokine pattern that includes interleukin-5 and formation of immunoglobulin E. This is in contrast to chronic rhinosinusitis without polyps, which exhibits T-helper-1 biased cytokine release. It is now evident that the cytokine environment is decisive regarding the impact of S. aureus derived enterotoxins, which function as superantigens. S. aureus enterotoxin B further shifts the cytokine pattern in nasal polyps toward T-helper-2 cytokines (increases greater than twofold for interleukin-2, interleukin-4 and interleukin-5), but it disfavours the T-regulatory cytokines interleukin-10 and transforming growth factor-beta1. Furthermore, S. aureus derived enterotoxins influence local immunoglobulin synthesis and induce polyclonal immunoglobulin E production, which may contribute to severe inflammation via activation of mast cells.

SUMMARY

From this new understanding of chronic rhinosinusitis with nasal polyps, new therapeutic approaches emerge such as anti-interleukin-5, anti-immunoglobulin E, and antibiotic treatment. These may enlarge the nonsurgical armentarium.

Staphylococcus aureus enterotoxin B regulates prostaglandin E2 synthesis, growth, and migration in nasal tissue fibroblasts

BACKGROUND

Superantigens and eicosanoids are important amplifiers and regulators of inflammation in airway diseases. We therefore studied the possible influence of Staphylococcus aureus enterotoxin B (SEB) on the cyclooxygenase (COX) pathway and basic functions of airway structural cells.

METHODS

Fibroblasts were isolated from nasal inferior turbinate tissue and cultured in the presence of different concentrations of SEB. Preincubation with interferon (IFN)-gamma was performed to induce expression of major histocompatibility complex (MHC) class II receptors. Prostaglandin E2 (PGE(2)) production was assayed by enzyme-linked immunosorbent assay, and levels of COX-2 and prostanoid E receptors 1-4 (EP(1-4)) were assayed by real-time polymerase chain reaction. Migration and growth tests were performed, and SEB was localized within the cells by confocal microscopy.

RESULTS

Stimulation with IFN-gamma and SEB significantly down-regulated PGE(2), COX-2, and EP(2) expression but not EP(1), EP(3), or EP(4) expression. The enterotoxin blocked cell growth but increased the fibroblast migration rate. SEB was localized within the cell in the presence and absence of MHC-II, suggesting that mechanisms other than conventional binding may allow the enterotoxin to enter the cell.

CONCLUSIONS

These findings may have major implications for our understanding of the role played by bacterial superantigens in regulating the inflammatory and remodeling mechanisms of upper airway diseases and hence may help elucidate the pathophysiology of these diseases.

Influence of leukotriene gene polymorphisms on chronic rhinosinusitis

BACKGROUND

Chronic rhinosinusitis (CRS) is increasingly viewed as an inflammatory condition of the sinonasal mucosa interacting with bacteria and/or fungi. However, factors conferring susceptibility to disease remain unknown. Advances in genomics offer powerful tools to explore this disorder. The goal of this study was to evaluate the effect of single nucleotide polymorphisms (SNP) on CRS in a panel of genes related to cysteinyl leukotriene metabolism.

METHODS

Severe cases of CRS and postal code match controls were recruited prospectively. A total of 206 cases and 200 controls were available for the present study. Using a candidate gene approach, five genes related to cysteinyl leukotriene metabolism were assessed. For each gene, we selected the maximally informative set of common SNPs (tagSNPs) using the European-derived (CEU) HapMap dataset. These SNPs are in arachidonate 5-lipoxygenase (ALOX5), arachidonate 5-lipoxygenase-activating protein (ALOX5AP), leukotriene C4 synthase (LTC4S), cysteinyl leukotriene receptor 1 (CYSLTR1) and cysteinyl leukotriene receptor 2 (CYSLTR2) genes.

RESULTS

A total of 59 SNPs were genotyped to capture the common genetic variations within these genes. Three SNPs located within the ALOX5, CYSLTR1 and ALOX5AP genes reached the nominal p-value threshold (p < 0.05) for association with CRS. However, none of these SNPs resist multiple testing adjustment.

CONCLUSION

While these initial results do not support that polymorphsims in genes assessed involved in the leukotriene pathways are contributing to the pathogenesis of CRS, this initial study was not powered to detect polymorphisms with relative risk of 2.0 or less, where we could expect many gene effects for complex diseases to occur. Thus, despite this lack of significant association noted in this study, we believe that validation with external populations and the use of better-powered studies in the future may allow more conclusive findings.

Safety of triflusal (antiplatelet drug) in patients with aspirin-exacerbated respiratory diseases

BACKGROUND AND AIMS

Aspirin, a cyclo-oxygenase (COX)-1 and COX-2 inhibitor, is the antiplatelet drug of choice to prevent serious vascular events. Adverse reactions to aspirin are frequent particularly among patients with asthma, chronic rhinosinusitis and nasal polyps. COX-1 inhibitors but not COX-2 inhibitors precipitate asthma attacks. Triflusal is a preferential COX-2 inhibitor antiplatelet agent that is as effective as aspirin in the prevention of serious vascular events. The aim of the study was to assess the tolerability of triflusal in patients with aspirin-exacerbated respiratory disease (AERD).

METHODS

We studied 26 asthma patients [11 males, aged 52 (23-75) years] who had suffered asthma episodes triggered by one or more (23% of patients) nonsteroidal anti-inflammatory drugs. Aspirin sensitivity was confirmed by either intranasal or oral aspirin challenge. All subjects underwent a single-blind, placebo-controlled oral challenge with three doses of triflusal separated by 1 week (first cumulative dose = 225 mg; second cumulative dose = 450 mg; third cumulative dose = 900 mg). Cutaneous, respiratory, general symptoms and lung function were monitored for 4 h in the laboratory and for 24 h at home.

RESULTS

No clinical reactions to triflusal were observed. There were no significant changes in lung function measurements.

CONCLUSION

Our study appears to demonstrate that triflusal is a suitable alternative to aspirin as antiplatelet agent to prevent AERD.

A sheep model for the study of biofilms in rhinosinusitis

BACKGROUND

Bacterial biofllms have been shown in chronic diseases such as cystic fibrosis, cholesteatoma, and otitis media with effusion. Recently, their detection on the mucosal tissue of sinusitis patients has implicated them in the pathogenesis of this condition. We present an animal model using sheep experimentally infected with Staphylococcus aureus to study the possible association between biofilm and sinusitis.

METHODS

Twenty-four sheep underwent bilateral endoscopic sinus surgery to identify their frontal ostia. The frontal sinuses were treated in one of the following ways according to preoperative randomization: (1) ostium left patent, (2) ostium left patent and bacteria instilled, (3) ostium occluded, or (4) ostium occluded and bacteria instilled. The frontal mucosa was harvested at day 7 and examined for biofilm presence using confocal scanning laser microscopy (CSLM) as well as scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

RESULTS

All three modalities showed different rates of biofilm detection. Three-dimensional structures that could be interpreted as biofilms were documented in 86% (n = 36) of the sinuses analyzed using SEM. These structures were seen in all four study groups. The detection rate using the other two modalities was much lower with CSLM, showing biofilms in 48% (n = 20) and TEM in only 29% (n = 12) of the sinuses analyzed. Unlike SEM, these two modalities only detected bacterial biofilms in sinuses randomized to bacterial instillation.

CONCLUSION

The demonstration of bacterial biofilms in this animal model of sinusitis further supports the hypotheses that biofilms may play a role in the pathogenesis of this condition. There is an obvious discrepancy in the sensitivity and specificity of biofilm detection using the three modalities mentioned. CSLM appears to be the most objective technique. The inherent flaws, sampling error, and subjectivity involved in SEM and TEM make these less reliable in documenting biofilm existence.

Confocal Scanning Laser Microscopy Evidence of Biofilms in Patients With Chronic Rhinosinusitis

OBJECTIVES

The recent detection of bacterial biofilms on the sinus mucosa of patients with chronic rhinosinusitis (CRS) has implicated biofilms in the pathogenesis of this condition. Electron microscopy has been the main modality used to document the presence of biofilms on sinus tissue, however, it has inherent problems associated with tissue preparation and sampling. Recently, Confocal Scanning Laser Micrsocopy (CSLM) has emerged as a noninvasive, nondestructive technique for the analysis of biofilms. This study used CSLM as the means of investigating biofilm presence in CRS patients.

STUDY DESIGN AND METHODS

A prospective study comparing the presence of bacterial biofilms on the sinus mucosa of CRS and control patients was conducted using CSLM. Thirty eight CRS patients undergoing endoscopic sinus surgery and nine control patients were enrolled in this study. Demographic and clinical information was recorded from each patient and intraoperatively, sinus culture specimens and mucosal samples were obtained for microbiologic and microscopic examination.

RESULTS

Using previously documented CSLM criteria, bacterial biofilms were found in 17 (44%) of the 38 CRS patients. No biofilm structures were evident in any of the controls. Patients having undergone previous sinus surgery seemed to have a higher incidence of biofilms compared with the incidence for those undergoing their first procedure. The difference however was not statistically significant. No correlation between positive bacterial cultures and biofilm presence was observed.

CONCLUSIONS

The CSLM detection of biofilms in CRS patients and their absence in controls further supports the hypothesis that biofilms may play a role in the pathogenesis of CRS. This study's lower reported incidence of biofilms compared with that of previous studies might reflect the increased accuracy of biofilm detection with CSLM.

Inflammatory mechanisms and remodeling in chronic rhinosinusitis and nasal polyps

Chronic rhinosinusitis (CRS) is presently classified into two subgroups: CRS without and CRS with nasal polyps. A variety of inflammatory mediators, including cytokines and chemokines, as well as adhesion molecules and matrix metalloproteinases, are upregulated in both subgroups of CRS; remodeling is also observed in both. However, there are also characteristic differences. Whereas CRS without nasal polyps has more neutrophilic infiltration, in CRS with nasal polyps (especially when associated with allergy/asthma) eosinophil infiltration is strikingly increased. Although several features of remodeling (eg, squamous metaplasia, basement membrane thickening, collagen deposition, hyperplasia of mucous glands, and goblet cells) are features seen in both subgroups of CRS, epithelial shedding as observed in asthma is not seen in either subgroup. Furthermore, pseudocyst formation seen in CRS with nasal polyps is not seen in CRS without nasal polyps.

Rhinosinusitis: Developing guidance for clinical trials

The Rhinosinusitis Initiative was developed by 5 national societies. The current guidance document is an expansion of the 2004 publication, "Rhinosinusitis: Establishing definitions for clinical research and patient care" and provides templates for clinical trials in antimicrobial, anti-inflammatory, and symptom-relieving therapies for the following: (1) acute presumed bacterial rhinosinusitis, (2) chronic rhinosinusitis (CRS) without nasal polyps, (3) CRS with nasal polyps, and (4) classic allergic fungal rhinosinusitis. In addition to the templates for clinical trials and proposed study designs, the Rhinosinusitis Initiative has developed 6 appendices, which address (1) health outcomes, (2) nasal endoscopy and staging of CRS, (3) radiologic imaging, (4) microbiology, (5) laboratory measures, and (6) biostatistical methods.

Role of prostaglandin D2 and E2 terminal synthases in chronic rhinosinusitis

BACKGROUND

Prostaglandin (PG)D(2) and E(2), two major cyclooxygenase (COX) products, are generated by PGD(2) synthase (PGDS) and PGE(2) synthase (PGES), respectively, and appear to mediate airway inflammation.

OBJECTIVE

We sought to determine the role of PGDS and PGES in the pathophysiology of chronic rhinosinusitis (CRS).

METHODS

The study examined the expression of PGDS and PGES in nasal polyps of 22 CRS patients. As controls, uncinate process mucosae were obtained from 12 CRS patients not having nasal polyps and five subjects without sinusitis. Immunohistochemistry and quantitative real-time PCR were used to evaluate the expression.

RESULTS

Both PGDS and PGES were detected in nasal polyps by immunohistochemistry. Significantly greater levels of PGDS mRNA and lesser levels of PGES mRNA were observed in the nasal polyps as compared with uncinate process mucosae, and an inverse correlation between PGDS and PGES expression was observed. Levels of PGDS mRNA in nasal polyps were positively correlated with degree of infiltration by EG2+ eosinophils, whereas the levels of PGES were inversely correlated. Significantly increased levels of PGDS and conversely decreased levels of PGES were observed in asthmatics as compared with non-asthmatics. In addition, PGDS and PGES levels were positively and inversely correlated with the radiological severity of sinusitis, respectively.

CONCLUSIONS

These results suggest that PGDS and PGES display an opposite and important role in the pathophysiology of CRS such as polyp formation, and more specifically, a biased expression of these synthases might contribute to the development of CRS by affecting eosinophilic inflammation.

Rhinosinusitis: developing guidance for clinical trials

The Rhinosinusitis Initiative was developed by 5 national societies. The current guidance document is an expansion of the 2004 publication "Rhinosinusitis: Establishing definitions for clinical research and patient care" and provides templates for clinical trials in antimicrobial, anti-inflammatory, and symptom-relieving therapies for the following: (1) acute presumed bacterial rhinosinusitis, (2) chronic rhinosinusitis (CRS) without nasal polyps, (3) CRS with nasal polyps, and (4) classic allergic fungal rhinosinusitis. In addition to the templates for clinical trials and proposed study designs, the Rhinosinusitis Initiative has developed 6 appendices, which address (1) health outcomes, (2) nasal endoscopy and staging of CRS, (3) radiologic imaging, (4) microbiology, (5) laboratory measures, and (6) biostatistical methods.

Drug management in chronic rhinosinusitis: identification of the needs

Chronic rhinosinusitis (CRS) is a group of multifactorial diseases characterized by inflammation of the mucosa of the nose and paranasal sinuses with a history of at least 12 weeks of persistent symptoms despite maximal medical therapy. The precise role played by infection and immunoglobin E (IgE)-mediated hypersensitivity remains unclear. Diagnosis of CRS is based upon medical history, nasal endoscopy and computed tomography scan of the sinuses. The CRS with polyps visible in the middle meatus must be distinguished from the CRS without polyps. Based on the current knowledge about the pathogenesis of CRS, it is admitted that an optimal medical treatment must consider all favorizing factors and control efficaciously the inflammation process. In case of failure of medical treatment, endoscopic sinus surgery should be proposed. However, some well-validated data and scientific evidences are missing, even for the most frequently used medications. After a review of the actual definitions and classifications, a short description of the current knowledge about pathogenesis of CRS is provided in order to justify the actual therapeutic rationales and identify the needs for an effective treatment of CRS.

The relationship between rhinosinusitis and asthma sinusitis

Chronic sinusitis comprises numerous disorders characterized by inflammation, mucous gland hyperplasia, and remodeling. Chronic hyperplastic eosinophilic sinusitis (CHES) is characterized by unrestrained proliferation of eosinophils, Th2-like lymphocytes, fibroblasts, goblet cells, and mast cells. The pathology of CHES is similar to that of asthma, and it is frequently diagnosed in association with asthma. It has been reported that exacerbations of CHES occur temporally with worsening of asthma; however, in the absence of well-controlled studies, this linkage remains unproven. In this article, the potential mechanisms linking these two diseases are examined.

Eicosanoid metabolism and eosinophilic inflammation in nasal polyp patients with immune response to Staphylococcus aureus enterotoxins

BACKGROUND

Staphylococcus aureus-derived enterotoxins (SEs) have been implicated in the pathogenesis of airway inflammatory diseases, especially nasal polyposis. However, the exact role of these molecules in the regulation of eicosanoid synthesis in this pathology remains unexplored. We studied the possible impact of SE-induced immune responses on the eicosanoid production in nasal polyp (NP) patients.

METHODS

Tissue sample homogenates from NP patients, with (NP-SEs[+]) and without detectable IgE-antibodies to SEs (NP-SEs[-]; ImmunoCap system), were assayed for IL-5, myeloperoxidase, leukotriene CJD4/E4 (LTC4/D4/E4), LTB4, lipoxin A4, total IgE, and eosinophil cationic protein.

RESULTS

Inflammatory makers, eicosanoids, and total IgE were significantly increased in NP-SEs(+) compared with NP-SEs(-) tissues, with the exception of myeloperoxidase, which was similar in both groups. Eicosanoid concentrations correlated to IL-5 and eosinophil cationic protein; however, only cys-leukotriene levels correlated with IgE-antibodies to SEs, independently of allergy and asthma.

CONCLUSION

Eicosanoid synthesis is up-regulated in polyp tissue of patients with immune response to SEs and seems to be related to the inflammatory reaction induced by these enterotoxins.

Mechanisms of aspirin sensitivity

In some asthma patients, nonsteroidal anti-inflammatory drugs (NSAIDs) induce bronchospasm, rhinorrhea, and nasal obstruction. NSAID-induced reactions appear to be caused by the inhibition of cyclooxygenase-1 (Cox-1); this in turn activates the lipoxygenase pathway, which eventually increases the release of cysteinyl leukotrienes (Cys-LTs) that induces bronchospasm and nasal obstruction. With regard to the metabolism of arachidonic acid (AA) in NSAID-intolerant asthmatic patients, the following changes have been observed: 1) A low production of prostaglandin E2, seemingly due to deficient Cox-2 regulation; 2) an increased expression of leukotriene-C4 synthase; and 3) a reduced production of metabolites (lipoxins) released through the transcellular metabolism of AA. NSAID-intolerant asthmatics have higher basal levels of Cys-LT than NSAID-tolerant asthmatics. Moreover, Cys-LT levels in NSAID-intolerant asthmatics increase remarkably following NSAID provocation testing. There has been no explanation to date that connects all these findings, although an anomaly in the regulation of Cox-2 is probably accountable.

Tissue remodelling in upper airways: where is the link with lower airway remodelling?

Tissue remodelling reported in upper airways include epithelial hyperplasia, increased matrix deposition in the nasal or paranasal lining, matrix degradation and accumulation of plasma proteins. Genetic influences, foetal exposures and early life events may contribute to structural changes such as subepithelial fibrosis from an early age. Other structural alterations are related to duration of the disease and long-term uncontrolled inflammation. Structural changes may increase alteration of the protective functions of the upper airways namely by affecting mucociliary clearance and conditioning of inspired air. The sequences of tissue changes during wound repair of upper airway mucosa after surgery are illustrative of the complexicity of tissue modelling and remodelling and could be considered as an important source of information for a better understanding of the complex relationship between inflammatory reaction, of the subsequent tissue damages and fibroblast metabolism of upper airways.

Bibliography. Current world literature. Nose and paranasal sinuses

PURPOSE OF REVIEW

Patients with advanced head and neck cancer are being treated with chemo-radiotherapy, and life is being prolonged, with or without persistent disease, for longer than was previously. Hypercalcaemia may present in patients with advanced or disseminated head and neck cancer, and, as such, these patients may present to a larger variety of clinicians for advice concerning their symptoms and illness. Modes of presentation of hypercalcaemia and treatment strategies are reviewed.

RECENT FINDINGS

There were previously few large series of head and neck cancer patients diagnosed with hypercalcaemia, which may or may not have been related to their cancer being treated. Investigations, by way of blood/serum calcium level, may identify such patients. Patients with cancer-related hypercalcaemia have a poor prognosis, but many may respond temporarily to treatment when offered, with an improvement of their quality of life and death.

SUMMARY

Hypercalcaemia should and must be considered in all patients who have or possibly have a diagnosis of a head and neck cancer and who present unwell with symptoms of fatigue, lethargy and somnolence. Investigation must include serum calcium (corrected for serum albumin binding) and parathyroid hormone level. Patients may be treated by a combination of rehydration and bisulphonate therapy until the serum calcium is reduced to a level below 3 mmol/l. The majority of patients diagnosed with hypercalcaemia due to head and neck malignancy die of their diseases in the short term, but some may enjoy a prolongation of life with reasonable quality if diagnosed and treated aggressively.

Expression of eicosanoid receptors subtypes and eosinophilic inflammation: implication on chronic rhinosinusitis

Background

Eicosanoid receptors are G-protein-coupled receptors playing an important immunomodulatory role in airway diseases. However, there is little information on the expression of these receptors and their link with eosinophilic inflammation in paranasal sinus diseases. We aimed with this study to investigate the tissue expression of leukotrienes and prostaglandin E2 receptors in chronic rhinosinusitis patients and the link of this regulation with eosinophilic inflammation.

Methods

Samples were prepared from nasal tissue of patients with chronic rhinosinusitis without nasal polyps (CRS, n = 11), with nasal polyps (CRS-NP, n = 13) and healthy subjects (Controls, n = 6). mRNA expression of CysLT₁, CysLT₂, BLT₁, BLT₂, E-prostanoid receptors (EP₁, EP₂, EP₃, EP₄) and sol-IL-5Rα was determined by real-time PCR. Concentrations of PGE2, LTC4/D4/E4, LTB4 and sol-IL-5Rα were determined by ELISA and of ECP by ImmunoCap. Protein expression and tissue localization of eicosanoid receptors and activated eosinophils were evaluated by immunohistochemistry.

Results

CysLT₁ mRNA expression was significantly increased in CRS-NP compared to CRS and controls, and CRS compared to controls, whereas CysLT₂ mRNA was enhanced in both CRS groups without differences between them. Levels of both receptors correlated to the number of activated eosinophils, sol-IL-5Rα, ECP and LTC₄/D₄/E₄ concentrations in the disease groups. PGE₂ protein concentrations and prostanoid receptors EP₁ and EP₃ were down-regulated in the CRS-NP tissue vs. CRS and controls, whereas EP₂ and EP₄ expression was enhanced in CRS and CRS-NP patients vs. controls. No differences in BLT receptors were observed between patients and controls.

Conclusion

CyLTs receptors are up-regulated in nasal polyp tissue and their expression correlate with eosinophilic inflammation supporting previous results. Eicosanoid receptors mRNA pattern observed suggests that down-regulation of EP₁ and EP₃ in CRS-NP and up-regulation EP₂ and EP₄ in CRS and CRS-NP groups may have some role in the development of the diseases and their regulation may not be directly linked to eosinophil activation but involve post-transcriptional events mainly related to other inflammatory cell sources.