Experimental Model of Fungal Sinusitis: A Pilot Study in Rabbits

Impact of Zinc Oxide on the Development of Aspergillus-Induced Maxillary Sinusitis Rabbit Model

Aspergillus fumigatus is commonly found in the airway and is associated with airway inflammatory diseases. Zinc oxide (ZO) is known to be an essential microelement that facilitates fungal survival, growth, and proliferation. This study aimed to investigate the impact of ZO on A. fumigatus-induced fungal sinusitis in rabbits. Twenty-eight New Zealand white rabbits were divided into four groups for this study. Group 1 (6 sides) was treated with intramaxillary phosphate buffer saline (PBS) served as the negative control, Group 2 (6 sides) received intramaxillary PBS and ZO, Group 3 (8 sides) was treated with intramaxillary A. fumigatus alone, and Group 4 (8 sides) treated with intramaxillary A. fumigatus with ZO. After 4 and 12 weeks, sinus mucosal cytokine and transcription factor expressions were determined. A histological analysis was performed to determine inflammatory cell infiltration, number of secretory cells, and mucosal thickness. Fungal biofilm formation was determined using confocal laser microscopy. The intramaxillary instillation of A. fumigatus conidia led to an increase in protein and mRNA expression of interleukin (IL)-1β and IL-8 in the maxillary sinus mucosa. They were associated with mitogen-activated protein kinase and activator protein-1. Furthermore, intramaxillary instillation of fungal conidia resulted in significant enhancement of inflammatory cell infiltration, epithelial thickening, and fungal biofilm formation. However, intramaxillary ZO did not have a significant impact on A. fumigatus-induced cytokine protein and mRNA expression, and inflammatory cell infiltration and epithelial thickness in sinonasal mucosa. While intramaxillary instillation of A. fumigatus increased mucosal inflammation, cytokine production, and biofilm formation, the intramaxillary application of ZO did not have a significant influence on inflammation in the maxillary sinus mucosa.

Fatal Aspergillus flavus rhinitis with gastrointestinal gaseous distension in a Cape porcupine

An adult female Cape porcupine (Hystrix africaeaustralis) was presented because of marked abdominal distension, acute dyspnea, and lethargy. Physical examination and standard radiographs revealed marked and diffuse gaseous dilation of the stomach and intestines of undetermined origin. The porcupine died despite medical therapy and surgical intervention. Postmortem examination revealed chronic fungal (Aspergillus flavus) rhinitis. Given that rodents are obligate nasal breathers, the rhinitis likely resulted in substantial upper airway obstruction leading to aerophagia.

Fungus Ball of the Maxillary Sinus-Modern Treatment by Osteoplastic Approach and Functional Endoscopic Sinus Surgery

PURPOSE

Functional endoscopic sinus surgery (FESS) is considered standard surgical therapy for fungus ball of the maxillary sinus. However, recent findings have indicated an odontogenic etiology, which requires simultaneous treatment of the dental origin. This study presents the authors' treatment results of fungus ball of the maxillary sinus using a combination of FESS and an endoscopically assisted osteoplastic approach through the anterior wall of the maxillary sinus, enabling simultaneous treatment of the dental origin.

MATERIALS AND METHODS

A cohort of 22 patients with histopathologically confirmed fungus ball of the maxillary sinus was retrospectively analyzed. Clinical records and medical imaging data were reviewed to evaluate the etiology, clinical and radiologic findings, and postoperative outcome.

RESULTS

Only 15 patients presented nonspecific clinical symptoms compatible with chronic unilateral maxillary sinusitis. Computed tomography visualized complete opacity of the maxillary sinus in 11 patients and intralesional hyperdensity in 12 patients. An odontogenic association was verified in 18 patients. Twenty-one patients underwent endoscopically assisted osteoplastic surgery through the anterior maxillary sinus wall. In 12 cases, the assumed persistent odontogenic source was treated simultaneously. Depending on the patency of the ostiomeatal complex, the accompanying chronic sinusitis was treated by FESS.

CONCLUSIONS

The present data support the assumption of an odontogenic etiology of fungus ball of the maxillary sinus. Hence, surgical management requires simultaneous treatment of the fungal mass, the odontogenic origin of the disease, and the accompanying chronic sinusitis. To properly treat fungus ball, the authors present a modern treatment concept, using a minimally invasive endoscopically assisted osteoplastic approach through the anterior maxillary wall, for sufficient and necessary surgical treatment.

Maxillary sinus volume: new physiopathological data in fungal ball genesis? A retrospective study

OBJECTIVES

The goal of this study was to compare maxillary sinus (MS) volume in patients with, or without, maxillary fungal ball.

DESIGN

Monocentric retrospective study performed on 115 patient CT scans.

SETTINGS

We defined two groups of patients according to the absence (control group) or the presence (fungal ball group) of unilateral fungal ball in the MS. Sinus 3D reconstruction was created from CT scan.

PARTICIPANTS

Control group: 71 patients (36 women - 50.7%); mean age was 51 years. Fungal ball group: 44 patients (29 women - 65.9%); mean age was 54.5 years.

MAIN OUTCOME MEASURE

The univariate association between MS volume and sinus covariates was tested by anova. Multivariate analysis was made including all variables statistically significant in univariate analysis.

RESULTS

In the control group, mean MS volume was 14 766 mm³ . The volumes of the two MSs were not statistically different in the control group (P = 0.145). In the fungal ball group, mean MS volume was 15 982 mm³ . Fungal ball was found in the smallest MS in 41 of 44 cases. Univariate analysis showed a statistical difference between the pathological and the non-pathological MS volumes (P < 10^-4 ). Multivariate analysis confirmed the correlation between MS volume and the presence of a fungal ball (P < 10^-4 ).

CONCLUSIONS

This study suggests that maxillary fungal ball is associated with a smaller size of the affected MS.

A novel fungus concentration-dependent rat model for acute invasive fungal rhinosinusitis: an experimental study

Background

Acute invasive fungal rhinosinusitis is a lethal infectious process afflicting immunocompromised individuals. Knowledge about this disease is still limited due to the scarcity of animal models designed to study the pathogenesis of this infection. Mast cells are tissue-resident immune cells that participate in a variety of allergic and inflammatory conditions. Limited attention has been given to the role of mast cells in acute invasive fungal rhinosinusitis. Therefore, the objectives of this study were to create a rat model of acute invasive fungal rhinosinusitis based on analyzing the impact of different fungal concentrations on establishing infection, and to observe the changes of mast cells in rats with this disease.

Methods

Sprague–Dawley rats were divided randomly into four groups, three of which were experimental and received different concentrations of Aspergillus fumigatus inoculations, and one was a control group (D). The inoculated Aspergillus fumigatus concentrations were 5 × 10⁷ conidia/ml in group A, 10⁷ conidia/ml in group B, and 10⁶ conidia/ml in group C. Before fungal inoculation, rats were immunosuppressed using cyclophosphamide and cortisone acetate, and had Merocel sponges inserted into the right nares. Hematology and histopathology investigations were then performed.

Results

An acute invasive fungal rhinosinusitis rat model was established successfully with an incidence rate of 90% in group A, 50% in group B and 10% in group C. Aspergillus fumigatus invasion was observed in 20% of the lungs in group A, but was not seen in the remaining groups. In addition, no fungi invaded the orbital tissue, brains, livers, spleens or kidneys of any rat. Compared with the control set, the total number of mast cells in the experimental groups was not significantly increased, but mast cell degranulation, on the other hand, was only found in infected nasal cavities.

Conclusions

This investigation illustrates that various fungal concentrations have different effects on the incidence of acute invasive fungal rhinosinusitis, and it also demonstrates the feasibility of using this model to study the process of fungal rhinosinusoidal invasion. In addition, the results suggest that mast cells may play a role in the protection of sinuses against acute Aspergillus fumigatus infection and in the clearance of established hyphal masses.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-014-0713-y) contains supplementary material, which is available to authorized users.

Review of experimental models: sinusitis in rabbits

Introduction

In order to better understand the pathophysiology of rhinosinusitis, several attempts have been made to create the disease in an animal model. Among the studied rodents each has its advantages and disadvantages. Rabbits are considered more appropriate for studies that require surgical manipulation or invasive procedures.

Objectives

To evaluate the most viable experimental model of rhinosinusitis in rabbits to be adopted in future studies.

Methods

An electronic search for studies with experimental models of rhinosinusitis in rabbits published in English and Portuguese between July of 1967 and January of 2013 was conducted in Medline, Pub Med, Cochrane, and CAPES databases, using the keywords “sinusitis”, “rabbits”, and “polyps”.

Results

A total of 256 studies were retrieved, but in accordance with the inclusion and exclusion criteria, only ten studies were selected. Many different methods of response assessment were used in these studies.

Conclusion

To date, there is no ideal experimental model for induction of acute or chronic rhinosinusitis in rabbits, but the rhinogenic model appears to be the most viable option for the continuity of studies of the disease.

A Novel Model of Invasive Fungal Rhinosinusitis in Rats

Background

Invasive fungal rhinosinusitis (IFRS) is a life-threatening inflammatory disease that affects immunocompromised patients, but animal models of the disease are scarce. This study aimed to develop an IFRS model in neutropenic rats.

Methods

The model was established in three consecutive steps: unilateral nasal obstruction with Merocel sponges, followed by administration of cyclophosphamide (CPA), and, finally, nasal inoculation with Aspergillus fumigatus. Fifty healthy Wistar rats were randomly divided into five groups, with group I as the controls, group II undergoing unilateral nasal obstruction alone, group III undergoing nasal obstruction with fungal inoculation, group IV undergoing nasal obstruction with administration of CPA, and group V undergoing nasal obstruction with administration of CPA and fungal inoculation. Hematology, histology, and mycology investigations were performed.

Results

The changes in the rat absolute neutrophil counts (ANCs) were statistically different across the groups. The administration of CPA decreased the ANCs, whereas nasal obstruction with fungal inoculation increased the ANCs, and nasal obstruction did not change them. Histological examination of the rats in group V revealed the hyphal invasion of sinus mucosa and bone, thrombosis, and tissue infarction. No pathology indicative of IFRS was observed in the remaining groups. Positive rates of fungal culture in tissue homogenates from the maxillary sinus (62.5%) and lung (25%) were found in group V, whereas groups I, II, III, and IV showed no fungal culture in the homogenates.

Conclusion

A rat IFRS model was successfully developed through nasal obstruction, CPA-induced neutropenia, and fungal inoculation. The disease model closely mimics the pathophysiology of anthropic IFRS.

Spectrum of fungal rhinosinusitis; histopathologist's perspective

AIMS

Clinical presentation can provide a clue to the subcategories of fungal rhinosinusitis (FRS); however, tissue examination provides accurate classification. The aim was to analyse the incidence and histopathological spectrum of FRS.

METHODS AND RESULTS

A retrospective analysis of all the cases of rhinosinusitis reported in the last 5 years was carried out. Haematoxylin and eosin-stained sections along with special stains such as periodic acid-Schiff and Grocott's were examined. These cases were subclassified based on the presence of allergic mucin, mycelial elements and tissue reaction. Out of a total of 665 cases of rhinosinusitis, 284 (42.7%) were of FRS. On histopathological examination they were broadly categorized as: (i) non-invasive FRS (n = 171, 60.2%), which included 160 cases (56.3%) of allergic fungal rhinosinusitis (AFRS) and eleven (3.9%) of fungal ball; (ii) invasive FRS (n = 101, 35.6%), which included 48 cases (16.9%) of chronic invasive granulomatous FRS, four (1.4%) of chronic invasive FRS and 49 (17.3%) of acute fulminant FRS; and (iii) mixed pattern FRS, comprising 12 cases (4.25%).

CONCLUSIONS

AFRS is the most common type of FRS. Cases with mixed reaction pattern suggest that different types of FRS represent a progressive spectrum of disease. An exact histopathological categorization of FRS is important as regards treatment.

Mouse model of Aspergillus and Alternaria induced rhinosinusitis

OBJECTIVE

Fungi are known to induce the production of chemical mediators from respiratory epithelial cells and have been increasingly recognized as important pathogens in sinusitis. However, the exact role of fungi in the pathogenesis of rhinosinusitis has not been clearly established. This study was performed to improve our understanding of the role of fungi in the pathogenesis of rhinosinusitis by developing an animal model of fungus induced rhinosinusitis.

METHODS

Fifty mice (C57BL6/J) were divided into five groups. Sham-operated group was the first group. In the second group, Aspergillus versicolor (Group IIa) and Alternaria alternata (Group IIb) (10(6)spores/ml) were inoculated into the nasal cavity. In the third group, fungi were inoculated into the nasal cavity in the presence of mucosal scratch (Group IIIa,b) and the fourth group was a nasal mucosal scratch only (Group IV). The fifth was a negative control (Group V). The fungi were inoculated once a week on six occasions and then the animals were sacrificed at 7 weeks. The histological sections were examined in a blind manner for the appearance of neutrophil clusters and epithelial thickness with hematoxylin-eosin stain, and mucus secreting glands using the Alcian blue/periodic acid Schiff stain.

RESULTS

Non-invasive fungal sinusitis had been induced with increased numbers of neutrophil clusters after Aspergillus and Alternaria exposure. The mice with the mucosal scratch wounds had significantly more inflammatory cell infiltration and epithelial thickening; but eosinophils were not commonly found. The mice with fungal sinusitis had goblet cell hyperplasia and increased mucus secretion in the sinonasal cavity.

CONCLUSIONS

Inoculation of fungi in the nasal cavity induced rhinosinusitis in C57BL6/J mice. This mouse model may be used for better understanding of the role of fungi in the pathogenesis of rhinosinusitis.

[Noninvasive fungal sinusitis (fungus ball)--diagnostic difficulties]

Noninvasive fungal sinusitis (fungus ball) is usually found in one sinus and the most frequently is caused by Aspergillus. Diagnostic criteria are based on histopathology, and fungal cultures are frequently negative. The clinical symptomatology mimics chronic rhinosinusitis and radiology, specially CT and MRI are helpful for making decision of surgery. The authors present 4 cases of fungus ball of the paranasal sinus. In one case clinical symptoms, endoscopic examination of nasal cavity and CT scans suggested foreign body in the maxillary sinus. In other case clinical and radiological evidences made us to thing of neoplasmatic disease of the frontal sinus. In remaining two cases mycetoma was found in the sphenoid sinus. Surgical removal was the treatment in all cases and followed by systemic antifungal therapy in one case because of bone destruction. Histopathology revealed hyphae of Aspergillus without evidence of tissue invasion, fungal cultures in two cases were negative, an in other two Aspergillus fumigatus culture were obtained.

Animal models: an important tool in mycology

Animal models of fungal infections are, and will remain, a key tool in the advancement of the medical mycology. Many different types of animal models of fungal infection have been developed, with murine models the most frequently used, for studies of pathogenesis, virulence, immunology, diagnosis, and therapy. The ability to control numerous variables in performing the model allows us to mimic human disease states and quantitatively monitor the course of the disease. However, no single model can answer all questions and different animal species or different routes of infection can show somewhat different results. Thus, the choice of which animal model to use must be made carefully, addressing issues of the type of human disease to mimic, the parameters to follow and collection of the appropriate data to answer those questions being asked. This review addresses a variety of uses for animal models in medical mycology. It focuses on the most clinically important diseases affecting humans and cites various examples of the different types of studies that have been performed. Overall, animal models of fungal infection will continue to be valuable tools in addressing questions concerning fungal infections and contribute to our deeper understanding of how these infections occur, progress and can be controlled and eliminated.

Comparative study of several sinusitis experimental modelling techniques in rabbits

Experimental models for clinical studies of rhinosinusitis are needed. Aim: to define a reliable, solid and reproducible experimental model for inflammatory rhinosinusitis with no innoculation of infectious agents in rabbits. Study design: Experimental. Material and Method: Twenty 20 rabbits were divided into 4 groups submitted to 4 different interventions: the placement of a unilateral nasal fossa sponge, unilateral obliteration of the nasal ostium with cyanoacrylate, unilateral placement of antigens in the maxillary cavity and unilateral placement of blood in the maxillary cavity. The animals were monitored for 15 days and then anesthetized and sacrificed; the maxillary sinuses were evaluated histologicaly and results were compared with controls and between the intervention groups. Conclusion: Sponje and glue as agents of meatal obstruction and toxoid aplied in the antrum are efficient as methods for rhinosinusitis modeling. Blood was not efficient in producing sinusitis.

Surgical treatment of Aspergillus mycetomas of the maxillary sinus: Review of the literature

The present study reviews the literature concerning the surgical treatment of Aspergillus mycetoma (AM) in the last 20 years to identify a gold standard surgical technique. Aspergillus mycetoma of the maxillary sinus, or mycetoma (fungus ball), is a noninvasive or extramucosal mycotic infection. Surgical removal of the sinus fungal masses to ensure drainage and aeration is performed using the traditional Caldwell-Luc (CL) procedure or endoscopic sinus surgery (ESS). Results of this review suggest that the gold standard surgical technique for AM is ESS with middle meatal antrostomy. General or local antifungal drugs are not indicated. Combined approach with an intraoral surgical access from the anterolateral wall of the maxillary sinus has to be reserved for selected cases in which ESS doesn't permit complete extraction of all fungal concretions or foreign bodies. The CL procedure should be avoided, because it has detrimental consequences for sinus physiology.

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.

Paranasal fungal sinusitis: contributions of histopathology to diagnosis: a report of 60 cases and literature review

Sixty cases of fungal sinusitis are presented from 2 institutions, accumulated from 1971 to 2005. Fifty cases were from a large suburban general hospital and 10 from a major university referral center. Two of the 50 and 3 of the 10, respectively, were immunocompromised patients and had acute fulminant disease. This suggests that encountering the various forms of this disease may, in part, be dependent on the referral nature of the institution. The remainder were immune competent and had chronic symptoms of nasal discharge, stuffiness, and facial pain. Imaging studies frequently showed sinus expansion, opacification, and bone erosion, although no clinical or radiographic features were predictive of extrasinus extension. Chronic fungal sinusitis is principally represented by fungus ball/mycetoma and allergic fungal sinusitis. The recent literature suggests a predominance of or a predominant interest in allergic fungal sinusitis. Hyphal colonies and the presence of allergic mucin with scattered organisms are histologic observations and are the respective keys to these diagnoses. However, the etiologic role of the fungus in chronic cases is not settled. Patients with chronic sinusitis who yield positive sinus cultures only, but have no organisms visualized histologically, are not universally regarded as having fungal sinusitis. The interest in fungal sinusitis has generated a prominent role for the pathologist. An awareness of the various forms of the disease and thorough histopathologic study, including submission of all tissues removed at surgery and recognition of allergic mucin, are essential. Acute fulminant/invasive fungal sinusitis may require frozen section for adequate management.