Staphylococcus aureus internalization in mast cells in nasal polyps: Characterization of interactions and potential mechanisms.

BACKGROUND: Chronic rhinosinusitis (CRS) with nasal polyps is a common chronic condition. The exact cause of nasal polyps remains unknown. Recently, we made the novel observation of intracellular localization of Staphylococcus aureus within mast cells in nasal polyps. OBJECTIVE: This follow-up study aimed to further characterize interactions between S aureus and mast cells in this setting and elucidate potential internalization mechanisms with particular emphasis on the role of staphylococcal enterotoxin B (SEB). METHODS: A prospective study was performed using an explant tissue model with ex vivo inferior turbinate mucosa obtained from patients with chronic rhinosinusitis with nasal polyps (n = 7) and patients without CRS (n = 5). Immunohistochemistry was used to characterize S aureus uptake into mast cells and investigate the effects of SEB on this process. An in vitro cell-culture model was used to investigate mast cell-S aureus interactions by using a combination of fluorescent in situ hybridization, confocal laser scanning microscopy, scanning electron microscopy, transmission electron microscopy, and proliferation assays. RESULTS: S aureus was captured by extracellular traps and entered mast cells through phagocytosis. Proliferating intracellular S aureus led to the expansion and eventual rupture of mast cells, resulting in release of viable S aureus into the extracellular space. The presence of SEB appeared to promote internalization of S aureus into mast cells. CONCLUSION: This study provides new insights into the interactions between S aureus and mast cells, including the internalization process, and demonstrates a prominent role for SEB in promoting uptake of the bacteria into these cells.

Alterations in cellular force parameters and cell projections in Nasal polyps-derived fibroblasts.

OBJECTIVE: Chronic Rhinosinusitis with Nasal Polyps (CRSwNP) is a disease that features a mechanical dysfunction involving chronic inflammation and altered tissue remodeling. In this study, we aim to evaluate the fibroblast morphology and its cellular traction force in primary fibroblasts cell cultures obtained from both healthy individuals (n=7) and patients with CRSwNP (n=8). METHODS: Using a Traction-force Microscopy we analyzed parameters of Force/Tension in fibroblasts cultures in both experimental groups. RESULTS: The analysis of the Projected Area of Cell revealed that fibroblasts derived from nasal mucosa of healthy individuals have an area on average 39.24% larger than the fibroblasts obtained from the nasal polyp tissue. We also observed that the parameters directly related to the force of the cell, Max Cumulative Force and Net Contractile Moment, presented a high Force/Tension per unit of area in the fibroblasts derived from the healthy nasal mucosa (on average 41% and 52.54% higher than the fibroblasts of the nasal polyp respectively). CONCLUSION: Our results demonstrate a cellular mechanism that may be associated with the mechanical dysfunction found in the Nasal Polyp tissue. The weak traction force of nasal polyp-derived fibroblast may, in lower dimensions, impact on the remodeling of nasal mucosa in CRSwNP.

Histological aspects of rhinosinusal polyps.

UNLABELLED: Contemporary cohort cross-sectional study. INTRODUCTION: Despite its importance for an accurate diagnosis, histology differences among nasal polyps and its clinical implications are rarely reported in the literature. The existing papers classify polyp samples without concern for prior treatments, which could influence the results attained. AIMS: carry out a morphological study, through light microscopy, of nasal polyps' structural alterations in the absence of any type of prior treatment and histologically classify it in relation to studies published in the literature. MATERIALS AND METHODS: We studied 89 patients with nasosinusal polyps without prior treatment. Polyp samples were collected by outpatient biopsy and analyzed through light microscopy after dyeing with hematoxylin-eosin. RESULTS: Samples were classified in the following way: Edematous or eosinophilic polyp 65 cases (73%); fibro-inflammatory polyp: 16 cases (18%); Polyp with Sero-mucinose gland hyperplasia: 06 cases (6.7%) and polyp with stroma atypia: 2 cases (2.3%). DISCUSSION: eosinophilic pattern prevailed in the patients with nasosinusal polyps of the population studied. This pattern is similar to the ones found in the major studies, which, however, do not mention prior treatment. CONCLUSION: after analyzing the polyps' histological characteristics, we noticed that the untreated polyps present a predominantly eosinophilic pattern.

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.

Regenerating cells in human airway surface epithelium represent preferential targets for recombinant adenovirus.

To investigate the efficiency of adenovirus-mediated gene delivery in regenerating human respiratory epithelium, we have performed infections with an E1- and E3-deleted type 5 recombinant adenovirus containing the Escherichia coli LacZ reporter gene on different culture models of regenerating human nasal polyp surface epithelium. These models included: (i) an ex vivo organ culture of nasal polyp tissue, (ii) an explant outgrowth cell culture, and (iii) an in vitro wound repair model, on dissociated cells. In ex vivo nasal polyp tissue, transduced cells were not detected in normal pseudostratified areas, but were found in areas of the surface epithelium with a morphology reminiscent of regenerating airway tissue. In the explant outgrowth cell culture, adenovirus-infected cells were preferentially detected at the periphery of the outgrowth. These transducible epithelial cells, representative of epithelial cells present in vivo during the process of surface airway epithelium regeneration, were shown to be migrating and poorly differentiated cells, which were proliferating or not. In the in vitro wound repair model, the efficiency of cell transduction was much higher in cells present in the wound area than in those far from the wound area. These results indicate that regenerating cells from human airway surface epithelium represent preferential targets for transgene expression, and suggest that efficiency of CFTR gene transfer by recombinant adenovirus vectors may be higher in regenerating CF airway mucosa than in normal tissue. However, since these cells do not show endogenous CFTR expression, the relevance of their preferential transduction for the functional correction of the ion transport defect in cystic fibrosis needs further investigations.

Lymphangioma presenting as a nasal polyp in an infant.

We describe a pedunculated lymphangioma presenting as an isolated nasal polyp in an 11-month-old male infant with light and electron microscopic findings. This lesion occurring in an infant must be distinguished from more common benign and malignant intranasal masses.

Stromal cell atypia in sinonasal polyposis.

Cellular atypia in stromal cells of nasal polyps is a peculiar response in fibroblasts or fibrohistiocytes to increased intercellular fluid and/or vascular compromise. Adherence to established histologic criteria will eliminate misjudging these cytologic changes as sarcomas.

Malignant transformation in inverted papilloma.

The detection of markers associated with malignancy will help in the early identification of tumors and assessment of the success of treatment in patients suffering from carcinoma. Three characteristics investigated in this study were found to differentiate a premalignant inverted papilloma from a benign simple nasal polyp.

Histologic structure of antrochoanal polyps.

The antrochonanal polyp (ACP) is defined as a maxillary sinus polyp that originates in the maxillary sinus, passes through the sinus ostia, and extends into the choana. The aim of this study was to compare the histologic findings of 40 cases of ACP with those of allergic and non-allergic nasal polyps, and so possibly to elucidate the pathogenesis of ACP. No allergy could be verified in any of the ACP patients. Inflammatory cell infiltration was significantly more severe in the ACP group than in the allergic polyp group. Eosinophilic infiltration was significantly less severe in the ACP group than in the allergic polyp group. Edema was not significantly different between the ACP, allergic, and non-allergic groups. In the ACP group, the presence of submucous glands was significantly less pronounced than in the ordinary nasal polyp groups. The fibrous type was present significantly more often than the infiltrative or granulating type in the ACP group. The histologic findings and clinical features of the ACP indicate that it has little causal relationship with nasal allergy but is all the more intimately associated with inflammatory processes. The paucity of submucous glands suggests that the ACP results from edematous hypertrophy of the respiratory epithelium rather than from distension of the glandular structures.

The nasal mucosa during long-term treatment with beclomethasone dipropionate aerosol. A light-and scanning electron microscopic study of nasal polyps.

Blind examination by light- and scanning electron miscroscope of a total of 142 biopsies from nasal polyps was carried out before and after continuous intranasal treatment with beclomethasone dipropionate aerosol, 400 microgram/day, for a period of 9-36 months. The degree of tissue oedema, the number of infiltrating eosinophil cells and the number of goblet cells in the epithelium decreased significantly. There was no change in the type of surface epithelium during treatment, and no tendency towards squamous cell metaplasia. The study suggests that beclomethasone dipropionate treatment for a period of a few years will not cause atrophic rhinitis.

Evaluation of the potential carcinogenicity and genetic toxicity to humans of the herbicide acetochlor.

Comprehensive toxicological studies of the herbicide acetochlor are presented and discussed. Although it gave a negative profile of responses in the many toxicity tests conducted there were some findings that prompted further investigation. First, although non-mutagenic in the Salmonella assay, acetochlor was clastogenic to mammalian cells treated in vitro. This clastogenic potential was not expressed in vivo in four rodent cytogenetic assays (bone marrow and germ cells). Second, although acetochlor gave a negative response in rat liver UDS assays when tested at the acute MTD, gavage administration of a single, supra-MTD dose (2000 mg/kg) gave a weak positive assay response. This dose-level (2000 mg/kg) was necrotic to the liver, depressed hepatic glutathione levels by up to approximately 80%, altered the metabolism of acetochlor, and was associated with up to 33% lethality. In contrast, reference liver genotoxins such as DMN, DMH and 2AAF were shown to elicit UDS in the absence of such effects, and at approximately 400 x lower dose-levels. Finally, microscopic nasal polypoid adenomas were induced in the rat when acetochlor was administered for two years at the maximum tolerated dose (MTD). The tumours were not life-threatening, they did not metastasize, and no DNA damage was induced in the nasal cells of rats maintained on a diet containing the MTD of acetochlor for either 1 or 18 weeks (comet assay). In order to probe the mechanism of action of these high dose toxicities a series of chemical and genetic toxicity studies was conducted on acetochlor and a range of structural analogues. These revealed the chloroacetyl substructure to be the clastogenic species in vitro. Although relatively inert, this substituent is preferentially reactive to sulphydryl groupings, most evidently, to glutathione (GSH). Similar chemical reactivity and clastogenicity in vitro was observed for two related chemicals bearing a chloroacetyl group, both of which have been defined as non-carcinogens in studies reported by the US.NTP. These collective observations indicate that the source of the clastogenicity of acetochlor in vitro is also the source of its rapid detoxification in the rat in vivo, via reaction with GSH. Metabolic studies of acetochlor are described which reveal the formation of a series of GSH-associated biliary metabolites in the rat that were not produced in the mouse. The metabolism of acetochlor in the rat changes with increasing dose-levels, probably because of depletion of hepatic GSH. It is most likely that a rat-specific metabolite is responsible for the rat nasal tumours observed uniquely at elevated dose-levels. The absence of genetic toxicity to the nasal epithelium of rats exposed acutely or subchronically to acetochlor favours a non-genotoxic mechanism for the induction of these adenomas. The observation of a time- and dose-related increase in S-phase cells in the nasal epithelium is consistent with this conclusion. Despite some confusion caused by the early use of perilethal gavage administrations of acetochlor to rodents, and supra-MTD dietary concentrations in some of the chronic studies, the available MTD data are consistent with acetochlor not posing a genetic or carcinogenic hazard to humans.

The ultrastructure of the nasal polyps in patients with and without cystic fibrosis.

Nasal polyps are commonly associated with cystic fibrosis (CF) and also with idiopathic allergies, asthma, and aspirin intolerance. The pathogenesis of nasal polyp formation is controversial. The present study investigates the ultrastructure of thirteen nasal polyps surgically removed from seven CF patients and six non-CF (NCF) patients with allergic diseases, asthma, and aspirin intolerance. All nasal polyps showed focal edema, hyperplasia, atrophy, or squamous metaplasia of the epithelium. The lamina propria was moderately populated with small blood vessels and mucous glands and showed focal accumulation of inflammatory cells. The CF nasal polyps, however, revealed several specific characteristics: 1) minimal damage to the surface epithelium, 2) presence of a mucus blanket lining the apical epithelium, 3) occasional intracytoplasmic lumens, 4) continuous and fenestrated type capillaries, 5) numerous degranulated mast cells, 6) many plasma cells, often with atypical morphology and intracisternal Russell bodies, and 7) a smaller number of eosinophils as compared to the NCF nasal polyps. The results indicate significant differences between CF and NCF nasal polyps and support the multifactorial pathways theory of nasal polyp formation.

New interpretations in rhinosporidiosis, enigmatic disease of the last nine decades.

Fungal etiology is widely quoted for the disease rhinosporidiosis. Identity of the fungal sporangium and its relationship with the disease have baffled medical scientists and mycologists for several decades. This study provides unequivocal evidence against involvement of fungus in rhinosporidiosis. The so-called sporangium is found to be a unique body containing residue-loaded lysosomal bodies ('spores') for elimination from the system. 'Sporangia' have been redesignated nodular bodies (NB) and 'spores' as spheres of cellular waste (scw). Two carbohydrates, namely defective proteoglycans synthesized intracellularly and an exogenous polysaccharide ingested through diet of tapioca constitute indigestible material in NB and scw. Polysaccharide in NB which has beta, 1-4 glycosidic bonds between mannose residues is not degraded by gastrointestinal enzymes nor in intracellular lysosomes which break only alpha-glycosidic bonds. A link between NB and dry tapioca has been deduced. Rhinosporidiosis is a complex phenotype with perhaps no parallel in medical science. This report erases 99 years (1892-1991) of controversies regarding 'causal organism' of rhinosporidiosis.

Nasal polyps: a comparative study of morphologic and etiopathogenetic aspects.

16 nasal polyps belonging to 10 male subjects aged between 40 and 70, have been removed during the same number of ethmoidectomies; the polyps have been sectioned and specimens of mucosa corresponding to the pedicle and to the different parts of the body have been collected. During the operation parts of the mucosa of the inferior turbinates were removed. All the specimens have been prepared and observed at the scanning electron microscope. The epithelium of the inferior turbinates, of the small polyps and of the apical part of all polyps were almost normal. Marked alterations of the epithelial layer have been observed in bigger polyps. Surface characteristics of nasal polyps seem to be influenced by their relationship with neighbouring structures and by their position in the nasal cavity, but mostly by their size. On the basis of these findings the authors discuss the most recent etiopathogenetic theories of nasal polyps. They finally describe some peculiar findings concerning the mucosal layer of the polyps and of the inferior turbinates of three confirmed allergic subjects and discuss their possible clinical implications.

Exudation into the nasal cavity of carbon particles injected into nasal polyps.

A colloidal carbon solution was prepared by dissolving 50 mg of ultra fine carbon particles (diameter: 21-50 nm) and polyvinylpyrrolidone-- for stabilizing the dispersion--in 1 ml physiological saline, and injected into the nasal polyps of allergic patients. Two hours after injection, the nasal polyps were removed and examined by transmission electron microscopy. Notably, carbon particles could not pass through the epithelial basement membrane and were therefore not observed between the epithelial cells, where no inflammatory cells infiltrated the epithelial layer. However, they passed through the fissure in the basement membrane, which was formed by the penetration of inflammatory cells (eosinophils) into the epithelial layer. Many carbon particles were observed in the interstitial space of the epithelial layer, where a large number of inflammatory cells accumulated. Furthermore, they passed into the nasal cavity along with the interstitial mucous fluid through the opened epithelial junction. A wide pathway from the submucosa to the nasal cavity, through which large-sized particles can pass, was demonstrated in the polyp's mucosa. Moreover, as carbon particles exhibit no chemotaxis, they must move according to the interstitial fluid flow, which suggests that the interstitial fluid flows outwardly from the mucosa during allergy.

[Demonstration of clusters in nasal polyps a light and electron microscopic investigation (author's transl)]. / Nachweis von "clusters" in Nasenpolypen.

Numerous functional studies have shown that lymphocytes and macrophages cooperate during the immune response. Cell clusters, consisting mainly of macrophages and lymphoid cells, were found in nasal polyps in humans, especially the oedematous type. Within the clusters the cells showed close physical contact brought about by microvilli of varying length, suggestive of cellular cooperation. These cell clusters resemble the formations found in vitro and in vivo during immunization procedures.

Noradrenergic innervation of nasal polyps and polypoid mucosae.

In order to study the sympathetic innervation of nasal polyps and polypoid mucosae, the glyoxylic catecholaminergic histofluorescence method was employed in the examination of specimens taken from patients who had nasal disorders with polyps or polypoid mucosae. One percent neutral red was used as a counterstain. Abundant sympathetic fibers were present around the vessels of the pedicle of nasal polyps. However, no sympathetic innervation was found in the body and apex of the polyps. In the microscopical views of polypoid formations, there were no obvious differences between non-diseased nasal mucosa and polypoid mucosa in the distribution of sympathetic innervation. Based on these results, the following conclusions were drawn: (1) The loss of the sympathetic innervation was suggested to an important role in the pathogenesis of nasal polyps. (2) During polypectomy, the polyp had better be removed along with the pedicle for there is abundant sympathetic innervation and it will result in reduced bleeding.

Mast cell ultrastructure in the inferior turbinate and stroma of nasal polyps.

Fourteen unselected adult patients with nasal polyps had ultrastructural examination of mast cells from matching biopsies of the polyp and inferior turbinate. Between three and 10 blocks were examined for each patient in both tissues and every mast cell that had a nucleus was photographed for study. Fifty-three mast cells were found within the stroma of nasal polyps and 54 in the submucosa of the inferior turbinate biopsies. The number of granules ranged between 13 and 167 (mean 60) for polyps and 18 and 148 (mean 61) in the inferior turbinate. The mast cells appeared essentially normal in the inferior turbinate of four patients. The degree of degranulation of the mast cells was calculated as in previous studies and then averaged for both the polyp and the inferior turbinate of each patient. There was greater degranulation in the nasal polyp compared to inferior turbinate (p = 0.03). These results were compared with mast cell degranulation found in the normal nose and in the inferior turbinate of patients with perennial allergic rhinitis which we previously published. The inferior turbinates in these patients were more degranulated than the normal nose (p = 0.0001) but were similar to that found in patients with perennial allergic rhinitis. This suggested that some degree of degranulation may occur throughout the nose in two thirds of the patients with nasal polyps which supports the theory that mast cell reactions are not limited to the polyps in a proportion of patients.

Nasal polyps. Scanning electron microscopy and artifact.

Nasal polyps are grossly oedematous tissue which has undergone considerable shrinkage when processed for scanning electron microscopy (SEM), converting the normally smooth surface into one with undulations. This shrinkage resulted in variable degrees of loss of the surface epithelium and thus gave rise to artifact. In its severest form, the entire surface epithelium was removed and the basement membrane exposed; lesser damage resulted in exposure of the basal cells, giving the previously described 'cobblestone' appearance. When the epithelium was intact, it was typical respiratory in type.

[Nasal polyps: comparative immunological study of polyps with different histopathologic types]. / I polipi naso-sinusali: studio immunoistologico comparativo di formazioni con differente tipologia istopatologica.

Cellular Infiltrate as well as class I and II HLA molecule expression, on 22 nasal polyps and on 12 samples of corresponding hypsilateral mucous membrane were studied by means of immuno-histological methods. These nasal polyps were classified according to their histopathological structure. Five polyps, with a fibrous connective core infiltrated by cells of the monocyte-macrophage lineage, were classified mixed. The remaining seventeen polyps were characterized by the presence of central oedematous connective tissue infiltrated almost exclusively by eosinophils and either contained (glandular type) or did not contain (oedematous type) glands. A comparative study of different types of nasal polyps and corresponding hypsilateral nasal mucous membranes was carried out on atopic and non-atopic patients. No correlation between atopic status and polyp presence or polyp typology was found. On the other hand, different polyp types appear to have a structural correlation with the corresponding hypsilateral mucous membrane regarding infiltrate cell type, oedematous or fibrous connective tissue presence and expression of on HLA antigen positivity pattern. The characteristic histological structure of hypsilateral mucous membranes in patients with different types of polyps appeared to be brought about by a multifactorial etiology involving mucosal hyperreactivity. Lastly, both polyps and parapolypal nasal mucous membranes were found to be infiltrated mainly in the peripheral subepithelial connective tissue by lymphocytes (55%) as well as by other leukocyte types. The presence of growth factors capable of enhancing an increase of fibroblasts, endothelial cells, together with focal distrupture on the basal membrane, might well be a general mechanism responsible for polyp sprouting.