OM Pathogenesis Research Articles

Predominant Bacterial and Viral Otopathogens Identified Within the Respiratory Tract and Middle Ear of Urban Australian Children Experiencing Otitis Media Are Diversely Distributed.

BackgroundOtitis media (OM) is one of the most common infections in young children, arising from bacterial and/or viral infection of the middle ear. Globally, Streptococcus pneumoniae and non-typeable Haemophilus influenzae (NTHi) are the predominant bacterial otopathogens. Importantly, common upper respiratory viruses are increasingly recognized contributors to the polymicrobial pathogenesis of OM. This study aimed to identify predominant bacteria and viruses in the nasopharynx, adenoids and middle ears of peri-urban/urban South-East Queensland Australian children, with and without clinical history of chronic otitis media with effusion (COME) and/or recurrent acute otitis media (RAOM).MethodsSixty children, 43 diagnosed with OM and 17 controls with no clinical history of OM from peri-urban/urban South-East Queensland community were recruited to the study. Respiratory tract bacterial and viral presence were examined within nasopharyngeal swabs (NPS), middle ear effusions (MEE) and adenoids, using real-time polymerase chain reaction (RT-PCR) and bacterial culture.ResultsAt least one otopathogen present was observed in all adenoid samples, 86.1% and 82.4% of NPS for children with and without OM, respectively, and 47.1% of the MEE from the children with OM. NTHi was the most commonly detected bacteria in both the OM and control cohorts within the adenoids (90.0% vs 93.8%), nasopharynx (67.4% vs 58.8%) respectively, and in the MEE (OM cohort 25.9%). Viruses were detected in all adenoid samples, 67.4% vs 47.1% of the NPS from the OM and control cohorts, respectively, and 37% of the MEE. Rhinovirus was the predominant virus identified in the adenoids (85.0% vs 68.8%) and nasopharynx (37.2% vs 41.2%) from the OM and control cohorts, respectively, and the MEE (19.8%).ConclusionsNTHi and rhinovirus are predominant otopathogens within the upper respiratory tract of children with and without OM from peri-urban and urban South-East Queensland, Australia. The presence of bacterial otopathogens within the middle ear is more predictive of concurrent URT infection than was observed for viruses, and the high otopathogen carriage within adenoid tissues confirms the complex polymicrobial environment in children, regardless of OM history.

The Roles of NOD-like Receptors in Innate Immunity in Otitis Media.

Acute otitis media (AOM) can persist or lead to various complications in individuals in which the innate immune system is impaired. In this context, impaired expression of nucleotide-binding oligomerization domain (NOD)-like receptor (NLR), an intracellular pathogen-recognition receptor (PRR), is involved in the etiology of OM in humans and animals, affecting its development, severity, chronicity, recurrence, and associated complications. To assess this relationship, we reviewed literature reports relating NLR expression patterns with the pathophysiology and clinical features of OM in the larger context of impaired innate immunity. We summarized the results of published studies on the expression of NLRs in animals and humans in acute otitis media (AOM), otitis media with effusion (OME), chronic otitis media (COM) with cholesteatoma, and COM without cholesteatoma. NLRs were expressed mainly in association with bacterial infection in AOM, OME, COM with cholesteatoma, and COM without cholesteatoma. In addition, expression of NLRs was affected by the presence or absence of bacteria, fluid characteristics, disease recurrence, tissue type, and repeated surgery. Various factors of the innate immune system are involved in the pathogenesis of OM in the middle ear. NLRs are expressed in AOM, OME, COM with cholesteatoma, and COM without cholesteatoma. Impaired NLR expression induced the development, chronicity and recurrence of OM and exacerbated associated complications, indicating that NLRs have important roles in the pathogenesis of OM.

GM-1111 reduces radiation-induced oral mucositis in mice by targeting pattern recognition receptor-mediated inflammatory signaling.

PurposeOral mucositis (OM) is a common, painful side effect of radiation therapy used for the treatment of head and neck cancer (HNC). Activation of the innate immune system upon irradiation has been identified as a key precipitating event of OM. To better understand OM’s pathogenesis, we studied pattern recognition receptors (PRRs) and their downstream pro-inflammatory cytokines in a mouse model of radiation-induced OM. We also tested therapeutic efficacy of GM-1111 that targets innate immune system to reduce radiation-induced OM.Methods and materialsThe pathogenesis of OM was studied in a single X-ray induced mouse model. The severity of OM was measured by visual and microscopical examinations. The irradiation-induced changes of PRRs and their downstream effector cytokine gene expression levels were determined. The efficacy of GM-1111 to reduce OM was tested in single and fractionated irradiation mouse models. The impact of the drug on tumor response to radiation therapy was also tested in a mouse model of human HNC.ResultsRadiation-induced tissue ulcerations were radiation-dosage and -time dependent. The lesions showed selective increases in PRR and pro-inflammatory cytokine gene expression levels. Once daily administration of GM-1111 (≥30 mg/kg, s.c.) significantly reduced the severity and the incidence of OM. The drug had little effect on PRRs but significantly inhibited downstream pro-inflammatory cytokine genes. GM-1111 did not interfere radiation therapy to induce HNC SCC-25 tumor regression. Instead, we observed significant drug-induced tumor regression.ConclusionsRadiation induces tissue damages. The increased expression levels of PRRs and their downstream pro-inflammatory cytokine genes in the damaged tissues suggest their important contribution to the pathogenesis of OM. Drug GM-1111 that targets these innate immune molecules may be a potential drug candidate as an intervention for OM.

Dysregulation of immune response in otitis media

ObjectiveOtitis media (OM) is a common reason for children to be prescribed antibiotics and undergo surgery but a thorough understanding of disease mechanisms is lacking. We evaluate the evidence of a dysregulated immune response in the pathogenesis of OM.MethodsA comprehensive systematic review of the literature using search terms [otitis media OR glue ear OR AOM OR OME] OR [middle ear AND (infection OR inflammation)] which were run through Medline and Embase via Ovid, including both human and animal studies. In total, 82 955 studies underwent automated filtering followed by manual screening. One hundred studies were included in the review.ResultsMost studies were based on in vitro or animal work. Abnormalities in pathogen detection pathways, such as Toll-like receptors, have confirmed roles in OM. The aetiology of OM, its chronic subgroups (chronic OM, persistent OM with effusion) and recurrent acute OM is complex; however, inflammatory signalling mechanisms are frequently implicated. Host epithelium likely plays a crucial role, but the characterisation of human middle ear tissue lags behind that of other anatomical subsites.ConclusionsTranslational research for OM presently falls far behind its clinical importance. This has likely hindered the development of new diagnostic and treatment modalities. Further work is urgently required; particularly to disentangle the respective immune pathologies in the clinically observed phenotypes and thereby work towards more personalised treatments.

Panel 7 – Pathogenesis of otitis media – a review of the literature between 2015 and 2019

ObjectiveTo perform a comprehensive review of the literature from July 2015 to June 2019 on the pathogenesis of otitis media. Bacteria, viruses and the role of the microbiome as well as the host response are discussed. Directions for future research are also suggested. Data sourcesPubMed database of the National Library of Medicine. Review methodsPubMed was searched for any papers pertaining to OM pathogenesis between July 2015 and June 2019. If in English, abstracts were assessed individually for their relevance and included in the report. Members of the panel drafted the report based on these searches and on new data presented at the 20th International Symposium on Recent Advances in Otitis Media. ConclusionsThe main themes that arose in OM pathogenesis were around the need for symptomatic viral infections to develop disease. Different populations potentially having different mechanisms of pathogenesis. Novel bacterial otopathogens are emerging and need to be monitored. Animal models need to continue to be developed and used to understand disease pathogenesis. Implications for PracticeThe findings in the pathogenesis panel have several implications for both research and clinical practice. The most urgent areas appear to be to continue monitoring the emergence of novel otopathogens, and the need to develop prevention and preventative therapies that do not rely on antibiotics and protect against the development of the initial OM episode.

Lack of the hyaluronan receptor CD44 affects the course of bacterial otitis media and reduces leukocyte recruitment to the middle ear

BackgroundCD44 is a multifunctional molecule that plays major roles in both leukocyte recruitment and tissue proliferation. Since mucosal hyperplasia and leukocyte infiltration of the middle ear cavity are major features of otitis media, we evaluated the role of CD44 in the pathophysiology and course of this disease in a mouse model of middle ear infection. Expression of genes related to CD44 function were evaluated using gene arrays in wild-type mice. The middle ears of mice deficient in CD44 were inoculated with non-typeable Haemophilus influenzae. Histopathology and bacterial clearance were compared to that seen in wild-type controls.ResultsWe observed strong up-regulation of CD44 and of genes related to its role in leukocyte extravasation into the middle ear, during the course of acute otitis media. Mice deficient in CD44 exhibited reduced early mucosal hyperplasia and leukocyte recruitment, followed by delayed resolution of infection and persistent inflammation.ConclusionsCD44 plays an important role in OM pathogenesis by altering the mucosal growth and neutrophil enlistment. Targeted therapies based on CD44 could be useful adjuncts to the treatment of middle ear infections.

Abstract 465: Regulation of HMGB1 release protects chemoradiotherapy-associated mucositis

Abstract Oral mucositis (OM) is a common complication in cancer patients undergoing anticancer treatment. Despite the clinical and economic consequences of OM, there are no drugs available for its fundamental control. Here, we show that high-mobility group box 1 (HMGB1), a “danger signal” that acts as a potent innate immune mediator, plays a critical role in the pathogenesis of OM. In addition, we investigated treatment of OM through HMGB1 blockade using NecroX-7 (tetrahydropyran-4-yl)-[2-phenyl-5-(1,1-dioxo-thiomorpholin-4-yl)methyl-1Hindole-7-yl]amine). NecroX-7 ameliorated basal-layer epithelial cell death and ulcer size in OM induced by chemotherapy or radiotherapy. This protective effect of NecroX-7 was mediated by inhibition of HMGB1 release and downregulation of mitochondrial oxidative stress. Additionally, NecroX-7 inhibited the HMGB1-induced release of TNF-α, IL-1β and MIP-1β, as well as the expression of p53-upregulated modulator of apoptosis (PUMA) and the excessive inflammatory microenvironment, including nuclear factor kB (NF-kB) pathways. In conclusion, our findings suggest that HMGB1 plays a key role in the pathogenesis of OM; therefore, blockade of HMGB1 by NecroX-7 may be a novel therapeutic strategy for OM. Citation Format: Keon-Il Im, Young-Sun Nam, Nayoun Kim, YuneJin Song, Young-Woo Jeon, Jung-Yeon Lim, Seok-Goo Cho. Regulation of HMGB1 release protects chemoradiotherapy-associated mucositis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 465.

Association of microRNA 146 with middle ear hyperplasia in pediatric otitis media

ObjectiveToll-like receptor signaling activated by bacterial otitis media pathogens in the middle ear has been shown to play a key role in OM susceptibility, pathogenesis and recovery. Recent studies implicate microRNA 146 (miR-146) in regulation of inflammation via negative feedback of toll-like receptor signaling (TLR) in a wide variety of tissues, however its involvement in otitis media is unknown. MethodsHuman middle ear epithelial cells were stimulated with proinflammatory cytokines, interleukin 1 beta or tumor necrosis factor alpha, for two to twenty-four hours. Middle ear biopsies were collected from children with otitis media with effusion (n = 20), recurrent otitis media (n = 9), and control subjects undergoing cochlear implantation (n = 10). miR-146a, miR-146b expression was assayed by quantitative PCR (qPCR). Expression of miR-146 targets involved in TLR signaling, IRAK1 and TRAF6, was assayed by qPCR in middle ear biopsies. Middle ear biopsies were cryosectioned and epithelial thickness measured by a certified pathologist. ResultsProinflammatory cytokines induced expression of miR-146 in middle ear epithelial cells in vitro. Middle ear miR-146a and miR-146b expression was elevated in otitis media patients relative to control subjects and correlated with middle ear epithelial thickness. A trend towards inverse correlation was observed between miR-146 and TRAF6 expression in the clinical population. ConclusionsThis report is the first to assess miRNA expression in a clinical population with OM. Findings herein suggest miR-146 may play a role in OM.

The Impact of Health Insurance Status on the Presentation, Local Management, and Outcomes of Patients With Head and Neck Cancer in the United States

12; Table 1 Adjusted outcomes for head and neck cancer patients according to health insurance status Insured Medicaid Uninsured HR 95% CI HR 95% CI HR 95% CI Overall mortality 1.00 – 1.55 1.49-1.62 1.48 1.38-1.58 Cause-specific mortality 1.00 – 1.60 1.55-1.69 1.65 1.52-1.79 Abbreviations: CI Z confidence interval; HR Z hazard ratio. International Journal of Radiation Oncology Biology Physics 870 mg x 7 wks (nZ4); 90 mg x 6 weeks (nZ4); 90 mg x 7 wks (nZ6). Efficacy: SOM duration, incidence through 6 wks/60 Gy, severity, and onset appeared markedly improved from historical controls (Table 1); overall SOM incidence (50% vs 70%) was also reduced. GC4419 efficacy was related to treatment duration (Table 1), but not absolute daily dose. Safety: A true maximum tolerated dose was not reached. Gr 3 gastroenteritis and Gr 3 nausea/vomiting (1 each, 112 mg/d x 3 or 6 wks) were considered dose-limiting. Dose-related Gr 1-2 peri-infusional facial tingling was attributable to GC4419. Other AEs were consistent with known effects of IMRT/CDDP. PK: Dose-related Cmax and AUC; plasma t1/2 approximately 2 hours. Biomarkers: Cy levels were associated with GC4419 dose and WHO severity, consistent with known OM pathogenesis. Conclusion: When GC4419 was given throughout IMRT, SOM was less frequent, briefer, delayed, and less severe than expected. GC4419-related toxicity was mild-to-moderate and acceptable in combination with IMRT/ CDDP. Doses of 30 and 90 mg/d were chosen for a future randomized, placebo-controlled trial. Author Disclosure: C.M. Anderson: Employee; University of Iowa Hospitals & Clinics. Uncompensated, involved in design of randomized Phase 2 trial of GC4419; Galera Therapeutics, Inc. B.G. Allen: Physician scientist, employed and self-funded through grants; University of Iowa Hospitals & Clinics. Research Grant; ASTRO. W. Sun: None. C.M. Lee: Partner; Cancer Care Northwest, Gamma Knife of Spokane. Speaker’s Bureau; Bayer Pharmaceuticals, Bristal Myers Squibb. Partnership; Kobold Medical Devices, Provenir Publishing. Committee Member; Sacred Heart Medical Center. S. Agarwala: None. M. Venigalla: None. L. Greenberg: None. D. Adkins: None. Y. Chen: None. W. Zhen: None. D. Mould: President; Projections Research Inc. Consultant; Projections Research Inc. J. Holmlund: Independent Contractor; Galera Therapeutics, Inc. Consultant; Baxalta, Prometheus Labs. Stock Options; Galera Therapeutics, Inc. Ad-hoc reviewer; Aspire IRB. J. Brill: Employee; Incyte Corporation. Stock Options; Galera Therapeutics, Inc, Incyte Corporation. S. Sonis: Senior Surgeon; Brigham and Women’s Hospital. Consultant; Clinical Assistance Programs. Stock; Inform Genomics. Partnership; BioInsight Diagnostics. Advisor; Galera. Board Member; Inform Genomics. J. Buatti: Research Grant; NIH.

Lovastatin protects keratinocytes from DNA damage-related pro-apoptotic stress responses stimulated by anticancer therapeutics

BackgroundOral mucositis (OM) is a relevant adverse effect of anticancer therapy involving ionizing radiation (IR) and doxorubicin (Doxo). Because DNA damage of keratinocytes is causative for the pathogenesis of OM, we aim to identify pharmacological measures for geno- and cytoprotection of keratinocytes. MethodsWe investigated the influence of the lipid-lowering drug lovastatin on cell death, proliferation and DNA damage response (DDR) mechanisms of human keratinocytes following treatment with IR and Doxo. ResultsLovastatin protected keratinocytes from the cytotoxic and genotoxic effects of IR and Doxo as shown by a diminished induction of apoptosis as well as a reduced formation and slightly improved repair of DNA damage following Doxo and IR treatment, respectively. Lovastatin selectively blocked the activation of Chk1 and ATR kinases following treatment with IR, Doxo and the ribonucleotide reductase inhibitor hydroxyurea, indicating that the statin antagonizes ATR/Chk1-regulated replicative stress responses. Part of the cytoprotective activity of lovastatin seems to rest on a delayed entry of lovastatin treated cells into S-phase. Yet, because the statin also protected non-proliferating keratinocytes from IR- and Doxo-induced cytotoxicity, cell cycle independent protective mechanisms are involved, too. ConclusionsLovastatin attenuates pro-toxic DNA damage-related responses of keratinocytes stimulated by OM-inducing anticancer therapeutics. The data encourage forthcoming in vivo and clinical studies addressing the usefulness of statins in the prevention of OM.

SNP-Based Bayesian Networks Define Oral Mucositis Risk in Patients Receiving Stomatotoxic Conditioning Regimens for Autologous Hematopoietic Stem Cell Transplantation

Abstract 735Oral mucositis (OM) is a clinically significant toxicity that occurs in approximately 40% of patients who receive standard conditioning regimens prior to autologous hematopoietic stem cell transplantation (aHSCT) as treatment for hematological malignancies. Not only does OM have broad symptomatic consequences, but its presence is associated with higher rates of local and systemic infection, longer hospital stays, and higher costs of care. Accurate prediction of patients at risk for OM would provide opportunities for directed prophylactic intervention.Given the biological complexities underlying OM pathogenesis, standard phenotypically directed risk assessment has largely defaulted to gene-based approaches. Typically candidate gene or genome-wide association studies (GWAS) have been used with mixed results. The former are hypothesis driven and thereby limited by current knowledge, while the latter are directed by expression thresholds and arbitrary linkages and, as such, are subject to high false-positive rates. In this study we applied a novel analytical approach in which we constructed a learned Bayesian network (BN) derived from single nucleotide polymorphism (SNP)-array outputs.Medical records of patients who underwent aHSCT for treatment of lymphoma or multiple myeloma (MM) at the DFCI from January 1, 2009, to July 1, 2010, were reviewed by trained study staff to identify individuals who did or did not develop OM (defined as > 2 consecutive days of a WHO score >2). Following informed consent, self-collected DNA (saliva) samples were obtained using a Genotek collection system. DNA was isolated and checked for quality. SNP arrays were processed using an Infinium DNA Analysis BeadChip (Illumina; ∼1.1 million SNPs).One hundred fifty-three adult patients (mean age 57 yrs; 42% female; 98% Caucasian) were included in the training set. Eighty-two MM patients received high-dose melphalan and the remainder were treated with BCNU, cyclophosphamide and etoposide (lymphomas). One hundred two patients were OM-negative.An 82 SNP BN was developed and was found to have a predictive accuracy for OM of 99.3% and an area under (AU) the Receiver Operator Characteristic (ROC) curve of 99.7%.These results support the concept that BN present a novel and effective way to identify specific aggregates of SNPs which are strongly associated with the risk of developing side effects from chemotherapy regimens. The fact that BNs are learned, rather than directed, inclusive of all SNPs, and provide cross-validation as the network is being built, results in a robust predictive SNP cluster that is likely to be more accurate in subsequent validation studies than has been the case with more conventional approaches. Clinical application of this methodology should result in prospective identification of patients at high risk for OM and thereby direct appropriate prophylactic interventions. Disclosures:Sonis:Inform Genomics, Inc.: Consultancy, Equity Ownership, Founding Partner Other. Alterovitz:Inform Genomics, Inc.: Consultancy, Equity Ownership.

Comparative Analysis of the Humoral Immune Response to Moraxella catarrhalis and Streptococcus pneumoniae Surface Antigens in Children Suffering from Recurrent Acute Otitis Media and Chronic Otitis Media with Effusion

A prospective clinical cohort study was established to investigate the humoral immune response in middle ear fluids (MEF) and serum against bacterial surface proteins in children suffering from recurrent acute otitis media (rAOM) and chronic otitis media with effusion (COME), using Luminex xMAP technology. The association between the humoral immune response and the presence of Moraxella catarrhalis and Streptococcus pneumoniae in the nasopharynx and middle ear was also studied. The levels of antigen-specific IgG, IgA, and IgM showed extensive interindividual variation. No significant differences in anti-M. catarrhalis and anti-S. pneumoniae serum and MEF median fluorescence intensity (MFI) values (anti-M. catarrhalis and antipneumococcal IgG levels) were observed between the rAOM or COME groups for all antigens tested. No significant differences were observed for M. catarrhalis and S. pneumoniae colonization and serum IgG levels against the Moraxella and pneumococcal antigens. Similar to the antibody response in serum, no significant differences in IgG, IgA, and IgM levels in MEF were observed for all M. catarrhalis and S. pneumoniae antigens between OM M. catarrhalis- or S. pneumoniae-positive and OM M. catarrhalis- or S. pneumonia-negative children suffering from either rAOM or COME. Finally, results indicated a strong correlation between antigen-specific serum and MEF IgG levels. We observed no significant in vivo expressed anti-M. catarrhalis or anti-S. pneumoniae humoral immune responses using a range of putative vaccine candidate proteins. Other factors, such as Eustachian tube dysfunction, viral load, and genetic and environmental factors, may play a more important role in the pathogenesis of OM and in particular in the development of rAOM or COME.

Multi-species bacterial biofilm and intracellular infection in otitis media

BackgroundBacteria which are metabolically active yet unable to be cultured and eradicated by antibiotic treatment are present in the middle ear effusion of children with chronic otitis media with effusion (COME) and recurrent acute otitis media (rAOM). These observations are suggestive of biofilm presence or intracellular sequestration of bacteria and may play a role in OM pathogenesis. The aim of this project is to provide evidence for the presence of otopathogenic bacteria intracellularly or within biofilm in the middle ear mucosa of children with COME or rAOM.MethodsMiddle ear mucosal biopsies from 20 children with COME or rAOM were examined for otopathogenic bacteria (either in biofilm or located intracellularly) using transmission electron microscopy (TEM) or species specific fluorescent in situ hybridisation (FISH) and confocal laser scanning microscopy (CLSM). One healthy control biopsy from a child undergoing cochlear implant surgery was also examined.ResultsNo bacteria were observed in the healthy control sample. In 2 of the 3 biopsies imaged using TEM, bacteria were observed in mucus containing vacuoles within epithelial cells. Bacterial species within these could not be identified and biofilm was not observed. Using FISH with CLSM, bacteria were seen in 15 of the 17 otitis media mucosal specimens. In this group, 11 (65%) of the 17 middle ear mucosal biopsies showed evidence of bacterial biofilm and 12 demonstrated intracellular bacteria. 52% of biopsies were positive for both biofilm and intracellular bacteria. At least one otopathogen was identified in 13 of the 15 samples where bacteria were present. No differences were observed between biopsies from children with COME and those with rAOM.ConclusionUsing FISH and CLSM, bacterial biofilm and intracellular infection with known otopathogens are demonstrated on/in the middle ear mucosa of children with COME and/or rAOM. While their role in disease pathogenesis remains to be determined, this previously undescribed infection pattern may help explain the ineffectiveness of current treatment strategies at preventing or resolving COME or rAOM.

HIF–VEGF Pathways Are Critical for Chronic Otitis Media in Junbo and Jeff Mouse Mutants

Otitis media with effusion (OME) is the commonest cause of hearing loss in children, yet the underlying genetic pathways and mechanisms involved are incompletely understood. Ventilation of the middle ear with tympanostomy tubes is the commonest surgical procedure in children and the best treatment for chronic OME, but the mechanism by which they work remains uncertain. As hypoxia is a common feature of inflamed microenvironments, moderation of hypoxia may be a significant contributory mechanism. We have investigated the occurrence of hypoxia and hypoxia-inducible factor (HIF) mediated responses in Junbo and Jeff mouse mutant models, which develop spontaneous chronic otitis media. We found that Jeff and Junbo mice labeled in vivo with pimonidazole showed cellular hypoxia in inflammatory cells in the bulla lumen, and in Junbo the middle ear mucosa was also hypoxic. The bulla fluid inflammatory cell numbers were greater and the upregulation of inflammatory gene networks were more pronounced in Junbo than Jeff. Hif-1α gene expression was elevated in bulla fluid inflammatory cells, and there was upregulation of its target genes including Vegfa in Junbo and Jeff. We therefore investigated the effects in Junbo of small-molecule inhibitors of VEGFR signaling (PTK787, SU-11248, and BAY 43-9006) and destabilizing HIF by inhibiting its chaperone HSP90 with 17-DMAG. We found that both classes of inhibitor significantly reduced hearing loss and the occurrence of bulla fluid and that VEGFR inhibitors moderated angiogenesis and lymphangiogenesis in the inflamed middle ear mucosa. The effectiveness of HSP90 and VEGFR signaling inhibitors in suppressing OM in the Junbo model implicates HIF–mediated VEGF as playing a pivotal role in OM pathogenesis. Our analysis of the Junbo and Jeff mutants highlights the role of hypoxia and HIF–mediated pathways, and we conclude that targeting molecules in HIF–VEGF signaling pathways has therapeutic potential in the treatment of chronic OM.

Immunopathogenesis of polymicrobial otitis media.

The synergistic relationship between URT viruses and bacteria in OM pathogenesis is not fully understood, but overall is predicated on viral impairment of airway defenses.

Mechanism of action of benzydamine in the treatment of oral mucositis

8040 Background: BZD has been proposed as a topical intervention for radiation-induced (RT) OM. BZD has been reported to have a range of biological activities that intervere with many of the mechanisms that are thought to be of importance in the pathogenesis of RT-induced OM. The objective of this study was to define the mechanisms by which BZD attenuates RT-induced OM. Methods: The effect of topically applied BZD on selected morphological and biological parameters was studied in temporal fashion to develop a descriptive pattern of events from which suggestions of mechanisms could be derived. 60 golden Syrian hamsters were randomized into 3 groups (G1 placebo n=32, G2 BZD n=32, G3 no treatment n=4). G1 and G2 animals were treated qd on day (d) 0 (day of RT) and then qid for 28d by injection into the left buccal cheek pouch. A single 37Gy radiation dose was administered to the left buccal pouch of all animals on d0. Four animals from G1 and G2 were sacrificed on d1,4,8,12,16,18 and 28, their left buccal pouches removed and the tissue studies for a variety of histological and immunohistochemical outcomes and markers. Results: Topical application of 0.15% BZD resulted in macroscopic attenuation of OM. A biphasic response characterized many study endpoints. Histological outcomes reflected tissue injury. BZD modified epithelial proliferation, but not differentiation. Observed changes correlated with a reduction in tissue levels of interleukin (IL)-1beta and tumor necrosis factor-alpha, but not IL-6. Preferential antiapoptotic activity was seen in epithelium and connective tissue of BZD-treated animals. Endothelial expression of COX-2 was altered by BZD. Conclusions: BZD’s effect in this model correlated with its selective attenuation of pro-inflammatory cytokines and its modification of epithelial and connective tissue apoptosis. These data do not indicate whether these effects are mechanistic drivers of OM or downstream markers of a more fundamental biological effect. Author Disclosure Employment or Leadership Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration McNeil Consumer and Specialty Pharmaceuticals Biomodels LLC, McNeil

A multinational, randomized phase iii trial of iseganan hcl oral solution for reducing the severity of oral mucositis in patients receiving radiotherapy for head-and-neck malignancy

PurposeOral mucositis (OM) causes significant morbidity during the course of radiotherapy (RT) treatment of head-and-neck cancer. It is hypothesized that infection plays a role in the development of OM. We tested the efficacy of iseganan HCl (iseganan), a synthetic peptide with broad-spectrum antimicrobial activity, for preventing RT-associated OM. MethodsA multinational, randomized, double-blind, controlled trial was performed on patients receiving primary RT, primary chemoradiotherapy or postoperative RT. Patients were randomized to receive iseganan oral solution plus standard-of-care oral hygiene (SOC), placebo plus SOC, or SOC alone throughout the RT administration period. The severity of OM was assessed by NCI-CTC scoring and clinical symptoms by patient questionnaire. ResultsA total of 545 patients were randomized to the study. Nine percent of the patients in both the iseganan and placebo groups did not develop ulcerative OM (Grades 2, 3, 4) (p = 0.998) whereas only 2% of the patients receiving SOC alone remained free of oral ulceration (p = 0.049). The maximum severity of mouth pain and difficulty swallowing did not differ in patients treated with iseganan or placebo. However, patients in both intervention groups reported less mouth pain and difficulty swallowing than did patients receiving SOC alone. Nausea was the only adverse event that occurred with ≥5% increased frequency in the iseganan group than in either the placebo or SOC groups (51% vs. 42% vs. 46%). Adverse events leading to study drug discontinuation and death did not differ significantly between groups. ConclusionIseganan oral solution was safe but did not reduce the risk for developing ulcerative OM relative to placebo. Intensified oral hygiene or the administration of the vehicle used to deliver study drug in this trial appears to have reduced the risk and severity of OM. Our results suggest that antimicrobial intervention may not meaningfully affect the pathogenesis of radiation-induced OM.

Bacterial otitis media: pathogenetic considerations.

A variety of exciting and important new observations regarding the pathogenesis of nontypable H. influenzae infection have been made in the past decade. The interactions between mucin and OMPs show a high degree of specificity. Multiple adhesins have been identified on the bacterial surface. Colonization of the upper respiratory tract is a dynamic process. Immunodominant, antigenically heterogeneous OMPs are the targets of strain-specific immune responses, accounting in part for the recurrent nature of OM in otitis-prone children. The LOS of nontypable H. influenzae displays a remarkable degree of antigenic and phase variation and may be involved in molecular mimicry of host antigens. Finally nontypable H. influenzae not only lives on the mucosal surface but also clearly has been demonstrated to enter epithelial cells and remain viable in intracellular and intercellular locations in the human upper respiratory tract. These areas of investigation have important implications in understanding the pathogenesis of OM. Elucidating mechanisms of pathogenesis will be important in guiding development of novel ways to prevent OM.

Effect of lacto-N-neotetraose, asialoganglioside-GM1 and neuraminidase on adherence of otitis media-associated serotypes ofStreptococcus pneumoniaeto chinchilla tracheal epithelium

The adherence ofStreptococcus pneumoniae(Spn) otitis media-associated serotypes 3, 6A and 14 to ciliated chinchilla respiratory epithelium was investigated using a whole organ perfusion technique. We demonstrated that Spn adhere to chinchilla tracheal epithelium within 30 min and exhibit saturation kinetics indicating that the effect being observed is receptor mediated. Inhibition of adherence was achieved by prior incubation of Spn with lacto-N-neotetraose (LNnT) or asialoganglioside GM1 (aGM1), recognized by glycoconjugate analogs of known Spn receptors. Neuraminidase treatment of the tracheae increased Spn adherencein vitroand reversed the inhibition effect of LNnT suggesting that neuraminidase treatment resulted in an increase in the number of available receptors for Spn. The chinchilla trachea organ perfusion culture system used in this study imitates eustachian tube conditions more closely than isolated cell culture systems and is a useful model for investigating the role of Spn adherencein vitroin the pathogenesis of OM.

Role of viruses in middle-ear disease.

Taken together, there is ample evidence suggesting a role for viruses in the pathogenesis of OM. This evidence comes from numerous studies performed in animals and in vitro cell cultures, as well as in adults and children with URI and OM. Viruses induce host immune and inflammatory responses that result in pathology of the ET and the middle ear, and predispose the host in various ways to secondary bacterial infection. A suggested mechanism for the pathogenesis of OM following respiratory viral infection is presented in Figure 1.