Enhanced phylogenetic insights into the microbiome of chronic rhinosinusitis through the novel application of long read 16S rRNA gene amplicon sequencing.

INTRODUCTION: 16S rRNA next generation sequencing (NGS) has been the de facto standard of microbiome profiling. A limitation of this technology is the inability to accurately assign taxonomy to a species order. Long read 16S sequencing platforms, including Oxford Nanopore Technologies (ONT), have the potential to overcome this limitation. The paranasal sinuses are an ideal niche to apply this technology, being a low biomass environment where bacteria are implicated in disease propagation. Characterising the microbiome to a species order may offer new pathophysiological insights. METHODOLOGY: Cohort series comparing ONT and NGS biological conclusions. Swabs obtained endoscopically from the middle meatus of 61 CRSwNP patients underwent DNA extraction, amplification and dual sequencing (Illumina Miseq (NGS) and ONT GridION). Agreement, relative abundance, prevalence, and culture correlations were compared. RESULTS: Mean microbiome agreement between sequencers was 61.4%. Mean abundance correlations were strongest at a familial/genus order and declined at a species order where NGS lacked resolution. The most significant discrepancies applied to Corynebacterium and Cutibacterium, which were estimated in lower abundance by ONT. ONT accurately identified 84.2% of cultured species, which was significantly higher than NGS. CONCLUSIONS: ONT demonstrated superior resolution and culture correlations to NGS, but underestimated core sinonasal taxa. Future application and optimisation of this technology can advance our understanding of the sinonasal microenvironment.

Position paper on olfactory dysfunction: 2023

BACKGROUND: Since publication of the original Position Paper on Olfactory Dysfunction in 2017 (PPOD-17), the personal and societal burden of olfactory disorders has come sharply into focus through the lens of the COVID-19 pandemic. Clinicians, scientists and the public are now more aware of the importance of olfaction, and the impact of its dysfunction on quality of life, nutrition, social relationships and mental health. Accordingly, new basic, translational and clinical research has resulted in significant progress since the PPOD-17. In this updated document, we present and discuss currently available evidence for the diagnosis and management of olfactory dysfunction. Major updates to the current version include, amongst others: new recommendations on olfactory related terminology; new imaging recommendations; new sections on qualitative OD and COVID-19 OD; updated management section. Recommendations were agreed by all co-authors using a modified Delphi process. CONCLUSIONS: We have provided an overview of current evidence and expert-agreed recommendations for the definition, investigation, and management of OD. As for our original Position Paper, we hope that this updated document will encourage clinicians and researchers to adopt a common language, and in so doing, increase the methodological quality, consistency, and generalisability of work in this field.

How I do it: Surgical management of maxillary sinus hemangiomas via prelacrimal approach.

Hemangiomas are tumours originating from the vascular endothelium and can be found throughout the body. These are relatively common in the head and neck regions but very rarely seen in sinonasal region. In the nose and sinuses tumours typically are seen on the septum or lateral nasal wall (1-4). These tumours can be quite vascular and bleed during attempted resection. Incomplete resection does result in residual disease or recurrence so the best approach to achieve complete resection is important.

The clinical outcomes of medical therapies in chronic rhinosinusitis are independent of microbiomic outcomes: a double-blinded, randomised placebo-controlled trial.

BACKGROUND: Oral and topical corticosteroids, and antibiotics form the mainstay medical treatment of chronic rhinosinusitis (CRS). Clinical outcomes vary depending on the chosen therapy, resident microbiome and disease phenotype. We conducted a double- blinded, placebo-controlled Randomised Controlled Trial (RCT) to investigate effects of medical therapy on clinical outcomes and associated microbiome shifts. METHODOLOGY: Fifty eligible patients (CRS with and without polyps) were treated for 3 weeks after randomisation into 3 arms: na- mely oral prednisolone, topical budesonide irrigations and oral doxycycline; each with appropriate placebo. Clinical scoring and microbiome swabs were performed on enrolment, at treatment completion and 3-weeks post treatment completion. Microbiome analysis was performed using the llumina-MiSeq next generation sequencing platform and QIME-2 pipeline. RESULTS: Significant improvement in clinical scores was observed in prednisolone and budesonide arms at treatment completion but not with antibiotic. Sub-group analysis showed more pronounced effects in patients with polyposis. Corynebacterium and Staphylococcus species predominated, with variable bacterial relative abundance among different treatments at all time-points. The only significant microbiome finding was an increase in bacterial diversity in topical budesonide group immediately after treatment, which returned to baseline 3-weeks post treatment. CONCLUSION: Clinical improvement was significant with oral and topical steroid but not empirical antibiotic. Although there were some associated microbiome changes with the various treatments, we could not ascertain the consistency of these and whether they do have a clinical significance at all.

The global transcriptomic signature in sinonasal tissues reveals roles for tissue type and chronic rhinosinusitis disease phenotype.

BACKGROUND: RNA sequencing (RNA-Seq) allows the characterization of a global transcriptomic signature in a least-biased fashion, but few studies have applied this method to investigate the pathophysiology of CRS. METHODS: We collected mucosal tissue samples from 6 CRS without nasal polyps (CRSsNP), 6 CRS with nasal polyps (CRSwNP), and 6 control patients. Additional matched polyp samples were collected from the 6 CRSwNP patients. RNA was extracted and sequenced on the Illumina HiSeq-2500. Differential gene expression and pathway analyses were performed. RESULTS: CRSsNP showed evidence of upregulated interferon-mediated immunity, MHC-class-I mediated antigen presentation, CXCR3 binding, neutrophil chemotaxis and degranulation, and potential downregulation of genes related to cilia movement and production. CRSwNP polyp tissue showed upregulation of B-cell mediated immune responses, but reduced expression of genes related to epithelial morphogenesis and haemostasis. Polyps also showed a generalized reduction of positive gene regulation. The sinonasal transcriptomic signature was largely determined by tissue type (polyp versus mucosa) and disease phenotype, with minimal signal originating from the individual patient. CONCLUSION: RNA-Seq is a useful tool to explore the complex pathophysiology of CRS. Our findings stress the importance of tissue selection in molecular research utilizing sinonasal tissue, and demonstrate the limitation of the sNP/wNP paradigm (and the importance of endotyping). On the other hand, classical CRSsNP/wNP disease phenotypes played some role in determining the global transcriptomic signature, and should not be hastily discarded. The value of RNA-Seq-described transcriptomic signatures in exploring endotypes is yet to be explored in future studies.

Zinc-depletion associates with tissue eosinophilia and collagen depletion in chronic rhinosinusitis.

BACKGROUND: Zinc plays an important role in many biological processes. Reduced zinc levels have been found in chronic rhinosinusitis (CRS) patients, however, its role in the pathophysiology of this disease remains unknown. This study examined zinc levels in the serum, mucus and tissue from CRS patients in relation to collagen content and eosinophil infiltration. The effect of zinc depletion on inflammatory cytokine production and collagen synthesis was assessed in vitro. METHODOLOGY: Zinc levels were determined in serum, mucus and tissue from controls, CRS with (CRSwNP) and without nasal polyps (CRSsNP) patients. Tissue zinc levels, collagen and inflammatory cell infiltration was examined using zinquin assays, immunofluorescence and histology on Tissue Micro Arrays. Cytokine expression and collagen synthesis was evaluated in zinc depleted primary human nasal epithelial cells (HNECs) and primary fibroblasts. RESULTS: CRSwNP patients showed reduced tissue zinc levels in correlation with a reduction in collagen content, and increased eosinophil numbers. Zinc depletion of HNECs and fibroblasts induced the production of pro-inflammatory cytokines and MUC5AC and reduced collagen secretion. CONCLUSIONS: These results suggest mucosal zinc depletion associates with tissue eosinophilia and collagen depletion in CRSwNP and induces pro-inflammatory cytokine expression and reduction of collagen synthesis in vitro.

Scoping review of chronic rhinosinusitis proteomics.

BACKGROUND: Progressive advances in proteomic technology has improved our understanding of the chronic rhinosinusitis (CRS) pathogenesis and endotypes. This scoping review aims to present a comprehensive and descriptive analysis of nasal mucosa and mucus proteome of CRS patients. METHODOLOGY: Studies investigating the proteome of nasal mucosa and mucus from healthy and CRS patients via mass spectrometry were included. Critical appraisal of methodological quality was conducted with extraction of protein lists. Gene set enrichment analysis (GSEA) was performed on studies including CRS patients. RESULTS: 2962 proteins were identified in the 21 studies included in this review. Eleven studies investigated the nasal mucus proteome and ten studies investigated the nasal mucosa proteome. Studies demonstrated heterogeneity in patients, sampling and mass spectrometry methodology. Samples from CRS patients suggested a trend in enrichment of immune system and programmed cell death pathways. Increased expression of proteins involved in cellular components including the cytoskeleton and adherens junctions was also present in CRS. CONCLUSIONS: Alterations in the healthy sinonasal proteome may lead to the increased immunological, metabolic and tissue remodeling processes observed in CRS. However, it is difficult to draw significant conclusions from the GSEA due to the heterogeneity present in the limited literature available. These findings allow us to direct further research to better understand CRS pathogenesis and its endotypes.

The persistence of intracellular Staphylococcus aureus in the sinuses: a longitudinal study.

BACKGROUND: Staphylococcus aureus (S. aureus) can reside within the sinonasal mucosa in chronic rhinosinusitis patients and causes recurrent infections. Within the host cell, S. aureus can evade host immune detection enabling its own survival. We hypothesise that S. aureus can persist within the sinonasal epithelium for a prolonged period without immune activation. METHODOLOGY: Patients with chronic rhinosinusitis with nasal polyps (CRSwNP) undergoing two sinus surgeries were included. Immunohistochemistry and Haematoxylin and Eosin stains were used to determine intracellular S. aureus (ICSA) status and inflammatory cell count, respectively. One-way ANOVA and paired t-tests were performed for comparison between ICSA subgroups and within each subgroup, respectively. RESULTS: Histopathological specimens from 34 patients (68 procedures) were included. ICSA positivity (ICSA+) was seen in 43 specimens (63.2%) from 26 (76%) patients. 18 (52.9%) of those were ICSA+ in both operations while 8 (23.5%) patients were ICSA+ in only one of the operations. 8 (23.5%) patients were ICSA negative in both operations. There was no difference in the number of eosinophils, lymphocyte and neutrophils between ICSA subgroups. CONCLUSIONS: This study demonstrated that S. aureus is found intracellularly within CRSwNP tissue at multiple time points without an increase in the number of eosinophils, lymphocytes and neutrophils. This finding supports our hypothesis that ICSA is able to escape from host detection and resides within the sinonasal mucosa despite intense treatment.

Th17 Cytokines Disrupt the Airway Mucosal Barrier in Chronic Rhinosinusitis.

Cytokine mediated changes in paracellular permeability contribute to a multitude of pathological conditions including chronic rhinosinusitis (CRS). The purpose of this study was to investigate the effect of interferons and of Th1, Th2, and Th17 cytokines on respiratory epithelium barrier function. Cytokines and interferons were applied to the basolateral side of air-liquid interface (ALI) cultures of primary human nasal epithelial cells (HNECs) from CRS with nasal polyp patients. Transepithelial electrical resistance (TEER) and permeability of FITC-conjugated dextrans were measured over time. Additionally, the expression of the tight junction protein Zona Occludens-1 (ZO-1) was examined via immunofluorescence. Data was analysed using ANOVA, followed by Tukey HSD post hoc test. Our results showed that application of interferons and of Th1 or Th2 cytokines did not affect the mucosal barrier function. In contrast, the Th17 cytokines IL-17, IL-22, and IL-26 showed a significant disruption of the epithelial barrier, evidenced by a loss of TEER, increased paracellular permeability of FITC-dextrans, and discontinuous ZO-1 immunolocalisation. These results indicate that Th17 cytokines may contribute to the development of CRSwNP by promoting a leaky mucosal barrier.

Association between group 2 innate lymphoid cells enrichment, nasal polyps and allergy in chronic rhinosinusitis.

BACKGROUND: Group 2 innate lymphoid cells (ILC2s) were shown to be involved in the initiation and coordination of Th2-type immune responses in allergic disease animal models. Recently, ILC2s enrichment was noted in chronic rhinosinusitis (CRS) patients; however, the role of ILC2s in coordinating the Th2 response in CRS remains to be elucidated. Here, we characterize the ILC2 compartment in CRS by investigating the correlations between ILC2s, Th2 cells and Th2 cytokines expression in CRS patients. METHODS: We used flow cytometric analysis of sinonasal mucosal tissues of 29 CRS patients and 5 controls to quantify ILC2s and Th2 cells. Messenger RNA expression levels of IL-5, IL-13, IL-25, IL-33, TSLP and GATA3 were determined using qRT-PCR. RESULTS: ILC2s were significantly enriched in nasal polyps (CRSwNP) patients. Multivariate linear regression showed a significant positive association of ILC2 numbers with CRSwNP and allergic CRS and a negative association with the number of previous endoscopic sinus surgeries. Group 2 innate lymphoid cell numbers significantly correlated with Th2 cell frequencies. Messenger RNA expression levels of IL-5 and IL-13 were increased in CRSwNP compared with controls, while mRNA levels of IL-25 and GATA3 were significantly reduced. CONCLUSIONS: Our results characterize the complex interactions between ILC2s and other Th2 response elements in the context of CRS and suggest that ILC2 enrichment occurs in CRSwNP and in allergic CRS patients.

Small-colony variants and phenotype switching of intracellular Staphylococcus aureus in chronic rhinosinusitis.

BACKGROUND: Chronic rhinosinusitis (CRS) has been linked to the gram-positive bacteria Staphylococcus aureus (S. aureus) in its biofilm or intracellular forms. Recent evidence suggests that S. aureus also exists in a small-colony variant (SCV) form as a mechanism of altering its virulence capabilities. The aim of this study was to investigate the presence of SCVs in sinonasal mucosa of CRS patients and whether the phenomenon of phenotype switching can be applied to intracellular epithelial infections. METHODS: Sinonasal specimens were examined for the presence of intramucosal S. aureus and characterized to the strain level. An airway epithelial cell culture infection model was utilized to investigate whether bacteria were capable of alterations in virulence phenotype. RESULTS: Intramucosal organisms harvested from sinonasal biopsies demonstrate phenotypic growth patterns and lack of coagulase activity consistent with SCVs. Intracellular infection of airway epithelial cell cultures with S. aureus led to decreased secretion of enterotoxins and phenotypic growth alterations consistent with SCVs. CONCLUSIONS: Regulation of S. aureus virulence factors is a dynamic process, and exposure to the intracellular environment appears to provide the necessary conditions to enable these alterations in an attempt for the bacterium to survive and persist within host tissues. Further work is required to ascertain whether SCVs in CRS hold a clinically relevant pathogenic role in recalcitrant disease.

Deferiprone and Gallium-Protoporphyrin Chitogel as an antimicrobial treatment: Preclinical studies demonstrating antimicrobial activity for S. aureus infected cutaneous wounds.

Staphylococcus aureus (S. aureus) is one of the most common wound pathogens with increased resistance towards currently available antimicrobials. S. aureus biofilms lead to increase wound chronicity and delayed healing. Chitosan-dextran hydrogel (Chitogel) loaded with the hydroxypyridinone-derived iron chelator Deferiprone (Def) and the heme analogue Gallium-Protoporphyrin (GaPP) have previously been shown to have antimicrobial effects in clinical sinusitis. In this study, the efficacy of Chitogel loaded with Def, GaPP and a combination of Def and GaPP, were investigated in an S. aureus biofilm infected wound murine model over 10 days of treatment. Bacterial wound burden was monitored daily showing a significant decrease in bacterial bioburden on days 6 and 8 when treated with Def-GaPP Chitogel (log10 1.0 and 1.2 reduction vs control, respectively). The current study demonstrates that the combination of Def-GaPP delivered in a Chitogel in vivo is not only effective in reducing S. aureus biofilm infection, but also improves cutaneous healing via effects on reduced inflammation, promotion of anti-inflammatory macrophage phenotype and marked early collagen deposition in the wound bed. This delivery platform presents a promising alternative non-toxic, antibacterial, wound-promoting treatment as a novel approach for the management of S. aureus wound infections that warrants further clinical investigation.

Inflammasome gene expression alterations in Staphylococcus aureus biofilm-associated chronic rhinosinusitis.

BACKGROUND: The role of inflammasomes in chronic inflammation has been the subject of intense research in recent years. Chronic rhinosinusitis (CRS), a persistent inflammatory disease, continues to be investigated hoping that a clearer pathophysiologic description will guide discovery of future treatment modalities. This study investigates the role of inflammasome complexes in CRS patients with Staphylococcus aureus biofilm infection, a key culprit associated with disease severity and recalcitrance. METHODOLOGY: Sinonasal tissue samples were collected from CRS patients with (P+) and without (P-) polyps and controls. S. aureus biofilm status was obtained using fluorescence in situ hybridization and classified as biofilm positive (B+) or negative (B-). RNA was analysed using a Human Inflammasome PCR array, profiling the expression of 84 genes involved in inflammasome function. RESULTS: Sixteen samples were obtained: 5 B+P+, 5 B-P- and 6 controls. Comparing B+P+ vs. controls showed the greatest number of differentially expressed genes. In particular, Absent in Melanoma 2 (AIM2) was consistently and significantly up-regulated in the B+P+ vs. B-P- and controls. In contrast, when comparing the B-P- vs. controls, no genes showed significant changes. CONCLUSION: Our results indicate the involvement of inflammasome complexes and their signalling pathways in CRS patients with polyps and S. aureus biofilms. In particular, AIM2, activated by intracellular double-stranded DNA, is up-regulated in this group, implying that S. aureus may play a role in intracellular triggering of the inflammasome response. Studies with further patient stratification and assessing corresponding protein expression are needed to further characterize the role of inflammasomes in CRS.

Mental workload during endoscopic sinus surgery is associated with surgeons' skill levels.

Introduction: Surgeons' mental workload during endoscopic sinus surgery (ESS) has not been fully evaluated. The assessment was challenging due to the great diversity of each patient's anatomy and the consequence variety of surgical difficulties. In this study, we examined the mental workload of surgeons with various surgical skill levels during ESS under the standardized condition provided by novel-designed 3D sinus models. Materials and methods: Forty-seven participants performed a high-fidelity ESS simulation with 3D-printed sinus models. Surgeons' mental workload was assessed with the national aeronautics and space administration-task load index (NASA-TLX). Associations between the total and subscales score of NASA-TLX and surgical skill index, including the board certification status, the number of experienced ESS cases, and the objective structured assessment of technical skills (OSATS), were analyzed. In addition, 10 registrars repeated the simulation surgery, and their NASA-TLX score was compared before and after the repetitive training. Results: The total NASA-TLX score was significantly associated with OSATS score (p = 0.0001). Primary component analysis classified the surgeons' mental burden into three different categories: (1) the skill-level-dependent factors (temporal demand, effort, and performance), (2) the skill-level-independent factors (mental and physical demand), and (3) frustration. After the repetitive training, the skill-level-dependent factors were alleviated (temporal demand; z = -2.3664, p = 0.0091, effort; z = -2.1704, p = 0.0346, and performance; z = -2.5992, p = 0.0017), the independent factors were increased (mental demand; z = -2.5992, p = 0.0023 and physical demand; z = -2.2509, p = 0.0213), and frustration did not change (p = 0.3625). Conclusion: Some of the mental workload during ESS is associated with surgical skill level and alleviated with repetitive training. However, other aspects remain a burden or could worsen even when surgeons have gained surgical experience. Routine assessment of registrars' mental burdens would be necessary during surgical training to sustain their mental health.

Endoscopic sinus surgery training courses: benefit and problems - a multicentre evaluation to systematically improve surgical training.

BACKGROUND: The aim of this multicentre study was to systematically analyse the strengths and weaknesses in the surgical training for endoscopic sinus surgery (ESS) and identify measures that may improve training. METHODOLOGY: Using a structured questionnaire, 133 participants of ESS courses in seven centres in Germany, Switzerland and Australia were asked about their experiences during their dissection courses and how they perceived their course could be improved. RESULTS: Gaining confidence in handling of instruments and endoscopes was only a problem for participants with little experience in ESS. The majority of the participants, independent from their level of training, considered infundibulotomy and anterior ethmoidectomy as the easiest dissection steps, whilst surgery of the frontal sinus posed a considerable challenge for many surgeons even those with a higher level of training. Participants with and without ESS experience thought that emphasis on anatomy was the most important improvement that could be made during their surgical training. Virtually all participants stated that the course improved their anatomical knowledge, their surgical skills and their confidence when performing ESS. CONCLUSIONS: ESS dissection courses are considered beneficial by surgical trainees. Participants felt that more emphasis on sinus anatomy in conjunction with private study is essential to maximize their skills in surgical dissection. For beginners with ESS, an infundibulotomy and anterior ethmoidectomy were thought to be the best initial procedures to help develop endoscopic surgical skills.

Diversity of immunoglobulin E-encoding transcripts in sinus mucosa of subjects diagnosed with non-allergic fungal eosinophilic sinusitis.

BACKGROUND: The role of allergy in the aetiopathogenesis of chronic rhinosinusitis (CRS) remains controversial. For example, in some cases with sinus fungal infections allergy can be demonstrated by standard tests. In other cases, such signs can be absent despite elevated levels of IgE-positive cells in sinus tissue and the presence of IgE and eosinophils in the sinus mucous. OBJECTIVE: To define the nature of molecular diversity in antibodies of the IgE isotype at the site of local inflammation in subjects diagnosed with non-allergic fungal eosinophilic sinusitis (NAFES). METHODS: The local occurrence and sequence characteristics of IgE-encoding transcripts in NAFES patients were investigated and compared with sequences found in subjects diagnosed with CRS featuring systemic allergy. These sequences have also been compared with other reported IgE-encoding transcriptomes. Results IGHV genes derived from major subgroups 1, 3, 4 and 5 and a diverse set of IGHD and IGHJ genes were shown to create the IgE repertoire in patients diagnosed with NAFES and CRS. The average lengths of the third hypervariable loop in these populations were 15.8 and 14.6 residues. The sequences showed evidence of extensive somatic hypermutation (mutation frequency: NAFES, 6.4 ± 3.2%; CRS, 7.0 ± 4.4%) with substitutions targeted to complementarity-determining regions. These sequence collections thus show extensive similarities to those found in other polyclonal Ig repertoires including those encoding IgE. CONCLUSION AND CLINICAL RELEVANCE: We conclude that sinus IgE-encoding transcripts in subjects diagnosed with NAFES show evidence of conventional IgE responses and we suggest that allergens with characteristics of classical antigens should be investigated for a role in the local response occurring in NAFES. This investigation illustrates that assessment of local immunity might be an important diagnostic tool in conditions like NAFES with no systemic signs of allergy to identify or rule out an allergic component of the patient's disease.

Adaptive immune responses in Staphylococcus aureus biofilm-associated chronic rhinosinusitis.

BACKGROUND: The etiopathogenesis of chronic rhinosinusitis (CRS) is currently an area of intense debate. Recently, biofilms have been proposed as a potential environmental trigger in this disease. In particular, Staphylococcus aureus biofilms appear to be a predictor of severe disease recalcitrant to current treatment paradigms. However, direct causal links between biofilms and host immune activation are currently lacking. This study aimed to document both the adaptive immune responses that characterize S. aureus biofilm-associated CRS and the relative contributions of staphylococcal superantigens and S. aureus biofilms in the inflammatory make-up of this disease. METHODS: A total of 53 disease subjects and 15 controls were recruited. Sinonasal mucosa was collected for the determination of S. aureus and Haemophilus influenzae biofilms and presence of total and superantigen-specific IgE and for the measurement of cytokines that characterize the T-helper pathways. RESULTS: Staphylococcus aureus biofilms and superantigens are significantly associated in CRS patients, suggesting the biofilm may be a nidus for superantigen-eluting bacteria. The presence of S. aureus biofilms is associated with eosinophilic inflammation, across the spectrum of CRS, on the back of a T-helper(2) skewing of the host's adaptive immune response (elevated Eosinophilic Cationic Protein and IL-5). This can be distinguished from the superantigenic effect resulting in the induction of IgE. CONCLUSION: This study provides novel evidence of a link between S. aureus biofilms and skewing of the T-cell response toward the T-helper(2) pathway that is independent of superantigen activities. Further research is required to confirm the cause-effect relationship of this association.

Patient-reported olfactory function following endoscopic sinus surgery with modified endoscopic Lothrop procedure / Draf 3.

OBJECTIVES/HYPOTHESIS: The Modified Endoscopic Lothrop procedure (MELP) or Draf 3 is a complex procedure, performed for chronic frontal sinusitis that is refractory to standard functional endoscopic sinus surgery. The procedure involves drilling of the frontal T (formed by the septum and middle turbinate`s attachment to the skull base) onto the olfactory fossa often with exposure of the first olfactory neuron and may affect olfactory function. This study was performed to assess patients` subjective sense of smell following this procedure. STUDY DESIGN: Prospective study of retrospective data. METHODS: Sixty-eight patients, who underwent modified endoscopic Lothrop by the senior author (PJW) between 2003 and 2008, completed a post-operative questionnaire asking about their perception of olfactory function. All patients had their pre-operative subjective sense of smell documented prior to undergoing surgery. Patient records were reviewed for pertinent medical information such as the presence of asthma, aspirin sensitivity and nasal polyps. RESULTS: This study found that the majority of patients reported improvement in their sense of smell post-operatively, while only a small number reported a negative impact on their smell. Thirty-nine patients reported an improvement in their post-operative smell grade. Twenty patients reported no change in their smell grade, while the remaining 9 patients stated that their sense of smell worsened after surgery. No statistically significant correlation was found between patient outcome and the presence of asthma, nasal polyps, or Samter`s triad. CONCLUSIONS: The Modified endoscopic Lothrop procedure/Draf 3 had a positive effect on subjective sense of smell post-operatively in this cohort of patients.

Prevention of adhesions post-abdominal surgery: Assessing the safety and efficacy of Chitogel with Deferiprone in a rat model.

INTRODUCTION: Adhesions are often considered to be an inevitable consequence of abdominal and pelvic surgery, jeopardizing the medium and long-term success of these procedures. Numerous strategies have been tested to reduce adhesion formation, however, to date, no surgical or medical therapeutic approaches have been successful in its prevention. This study demonstrates the safety and efficacy of Chitogel with Deferiprone and/or antibacterial Gallium Protoporphyrin in different concentrations in preventing adhesion formation after abdominal surgery. MATERIALS AND METHODS: 112 adult (8-10 week old) male Wistar albino rats were subjected to midline laparotomy and caecal abrasion, with 48 rats having an additional enterotomy and suturing. Kaolin (0.005g/ml) was applied to further accelerate adhesion formation. The abrasion model rats were randomized to receive saline, Chitogel, or Chitogel plus Deferiprone (5, 10 or 20 mM), together with Gallium Protoporphyrin (250µg/mL). The abrasion with enterotomy rats were randomised to receive saline, Chitogel or Chitogel with Deferiprone (1 or 5 mM). At day 21, rats were euthanised, and adhesions graded macroscopically and microscopically; the tensile strength of the repaired caecum was determined by an investigator blinded to the treatment groups. RESULTS: Chitogel with Deferiprone 5 mM significantly reduced adhesion formation (p<0.01) when pathologically assessed in a rat abrasion model. Chitogel with Deferiprone 5 mM and 1 mM also significantly reduced adhesions (p<0.05) after abrasion with enterotomy. Def-Chitogel 1mM treatment did not weaken the enterotomy site with treated sites having significantly better tensile strength compared to control saline treated enterotomy rats. CONCLUSIONS: Chitogel with Deferiprone 1 mM constitutes an effective preventative anti-adhesion barrier after abdominal surgery in a rat model. Moreover, this therapeutic combination of agents is safe and does not weaken the healing of the sutured enterotomy site.

Fluticasone Propionate Suppresses Poly(I:C)-Induced ACE2 in Primary Human Nasal Epithelial Cells.

Background: From the first detection in 2019, SARS-CoV-2 infections have spread rapidly worldwide and have been proven to cause an urgent and important health problem. SARS-CoV-2 cell entry depends on two proteins present on the surface of host cells, angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine 2 (TMPRSS2). The nasal cavity is thought to be one of the initial sites of infection and a possible reservoir for dissemination within and between individuals. However, it is not known how the expression of these genes is regulated in the nasal mucosa. Objective: In this study, we examined whether the expression of ACE2 and TMPRSS2 is affected by innate immune signals in the nasal mucosa. We also investigated how fluticasone propionate (FP), a corticosteroid used as an intranasal steroid spray, affects the gene expression. Methods: Primary human nasal epithelial cells (HNECs) were collected from the nasal mucosa and incubated with Toll-like receptor (TLR) agonists and/or fluticasone propionate (FP), followed by quantitative PCR, immunofluorescence, and immunoblot analyses. Results: Among the TLR agonists, the TLR3 agonist Poly(I:C) significantly increased ACE2 and TMPRSS2 mRNA expression in HNECs (ACE2 36.212±11.600-fold change, p<0.0001; TMPRSS2 5.598±2.434-fold change, p=0.031). The ACE2 protein level was also increased with Poly(I:C) stimulation (2.884±0.505-fold change, p=0.003). The Poly(I:C)-induced ACE2 expression was suppressed by co-incubation with FP (0.405±0.312-fold change, p=0.044). Conclusion: The activation of innate immune signals via TLR3 promotes the expression of genes related to SARS-CoV2 cell entry in the nasal mucosa, although this expression is suppressed in the presence of FP. Further studies are required to evaluate whether FP suppresses SARS-CoV-2 viral cell entry.