Chronic suppurative otitis media causes macrophage-associated sensorineural hearing loss

Gram-negative Bacteria are Associated With Sensorineural Hearing Loss in Chronic Otitis Media

OBJECT

Chronic otitis media (COM) is an inflammatory disease that commonly presents with otorrhea and hearing loss. Bacteria-induced inflammation can cause inner ear damage, leading to sensorineural hearing loss (SNHL). This study aimed to compare the prevalence and severity of SNHL in patients with gram-negative versus gram-positive cultures and examine associations between the concentrations of circulating monocytes and neutrophils with bacteria species and SNHL.

METHODS

This was a retrospective study. Cholesteatoma or chronic suppurative otitis media patients with otorrhea were enrolled. Middle ear secretions were collected using sterile swabs under an otoscope, and sent for bacterial detection within 30 min. Pure tone audiometry and circulating leukocyte counts were recorded and analyzed in patients infected with different pathogens. Logistic regression analysis was used to identify the risk factors associated with SNHL.

RESULTS

A total of 137 patients were enrolled, including 45 patients infected with gram-negative bacteria, 41 with gram-positive bacteria, 20 with polymicrobial infection, and 31 with no bacterial growth. Logistic regression analysis showed that bacterial culture positive infections (OR = 7.265, 95% CI 2.219-23.786, p = 0.001) were an independent risk factor for SNHL. Patients with gram-negative bacteria had higher risks of SNHL (p < 0.0001) and more severe hearing loss (p = 0.005) than those with gram-positive bacteria. COM patients infected with gram-negative bacteria showed an increase in circulating monocytes, which correlated with the occurrence of SNHL (p = 0.0343).

CONCLUSION

Gram-negative bacteria are associated with elevated circulating monocyte counts and have a higher risk of severe SNHL.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:3335-3341, 2024.

'We know the lack of services': Service lead's perspective of enablers and barriers to hearing assessment for children in metropolitan, regional and rural Australia: A qualitative study

OBJECTIVE

To explore potential enablers and barriers to accessing paediatric hearing assessment from the perspective of Australian service leads, extending previous studies on this topic from the perspectives of two other stakeholder groups - parents and speech pathologists.

DESIGN

This qualitative study, expanding upon previous mixed-methods studies, applied a pragmatism paradigm.

SETTING

The study was undertaken online via Zoom and included participants who were service leads of organisations that offer hearing assessment in metropolitan, regional, rural and remote parts of Australia.

PARTICIPANTS

Eight Australian service leads participated in semi-structured interviews.

RESULTS

Barriers identified were similar to barriers in previous studies. Three main themes were identified. First, children with hearing loss in Australia are well identified at birth. The second theme focused on the reduced and inconsistent hearing assessment services available after this age. Finally, service leads discussed the importance of embracing technology to solve service access difficulties.

CONCLUSION

Consultation with key stakeholders, to consider the needs of different communities within Australia, will be crucial when identifying new service delivery options.

Epidemiology of Chronic Suppurative Otitis Media in the United States

OBJECTIVE

This study aimed to evaluate the prevalence, incidence, and associated demographic factors of chronic suppurative otitis media (CSOM), utilizing a nationwide healthcare claims database.

METHODS

This retrospective study utilized outpatient administrative claims data from the IBM MarketScan Research Database from 2007 to 2021. The database (11 246 909 584 claims with 148 147 615 unique patients) includes health data from the private-sector, Medicare/Medicaid, managed care providers, and EMR providers. Included patients had a diagnosis of CSOM based on ICD-9-CM and ICD-10-CM codes. Prevalence and health utilization were estimated by age, gender, and geographic region.

RESULTS

In the United States, the estimated CSOM prevalence and incidence was 0.46% and 0.03%, respectively. Among CSOM patients (n = 679 906), mean age (SD) was 8.1 (15.4) years, and 52.8% were male. Most patients (81.1%) were aged 0 to 10 years. CSOM prevalence was lower in females (OR = 0.64, 95% CI 0.64-0.65, P < .001), less common in older age (OR = 0.94, 95% CI 0.94-0.94, P < .001), and highest in the South region (OR = 2.08, 95% CI 2.06-2.09, P < .001).

CONCLUSION

Our results show CSOM prevalence (0.46%) is similar to other developed countries. CSOM prevalence was highest in those aged 0 to 10 years, in males and in the South region. Of note, prevalence and cost are likely significantly underestimated given limitations in accurate ICD-CM coding and the exclusion of uninsured patients. Further epidemiological studies are warranted to characterize the impact of CSOM on the US healthcare system.

Anti-inflammatory properties and characterization of water extracts obtained from Callicarpa kwangtungensis Chun using in vitro and in vivo rat models

Callicarpa kwangtungensis Chun (CK) is a common remedy exhibits anti-inflammatory properties and has been used in Chinese herbal formulations, such as KangGongYan tablets. It is the main component of KangGongYan tablets, which has been used to treat chronic cervicitis caused by damp heat, red and white bands, cervical erosion, and bleeding. However, the anti-inflammatory effects of CK water extract remains unknown. This study assessed the anti-inflammatory effects of CK in vivo and in vitro, characterized its main components in the serum of rats and verified the anti-inflammatory effects of serum containing CK. Nitric oxide (NO), tumour necrosis factor α (TNF-α) and interleukin-6 (IL-6) release by RAW264.7 cells was examined by ELISA and Griess reagents. Inflammation-related protein expression in LPS-stimulated RAW264.7 cells was measured by western blotting. Furthermore, rat model of foot swelling induced by λ-carrageenan and a collagen-induced arthritis (CIA) rat model were used to explore the anti-inflammatory effects of CK. The components of CK were characterized by LC-MS, and the effects of CK-containing serum on proinflammatory factors levels and the expression of inflammation-related proteins were examined by ELISA, Griess reagents and Western blotting. CK suppressed IL-6, TNF-α, and NO production, and iNOS protein expression in LPS-stimulated RAW264.7 cells. Mechanistic studies showed that CK inhibited the phosphorylation of ERK, P38 and JNK in the MAPK signaling pathway, promoted the expression of IκBα in the NF-κB signaling pathway, and subsequently inhibited the expression of iNOS, thereby exerting anti-inflammatory effects. Moreover, CK reduced the swelling rates with λ-carrageenan induced foot swelling, and reduced the arthritis score and incidence in the collagen-induced arthritis (CIA) rat model. A total of 68 compounds in CK water extract and 31 components in rat serum after intragastric administration of CK were characterized. Serum pharmacological analysis showed that CK-containing serum suppressed iNOS protein expression and NO, TNF-α, and IL-6 release. CK may be an anti-inflammatory agent with therapeutic potential for acute and chronic inflammatory diseases, especially inflammatory diseases associated with MAPK activation.

"The barriers are plentiful." Speech-language pathologists' perspectives of enablers and barriers to hearing assessment for children in metropolitan, regional, and rural Australia: A mixed methods study

PURPOSE

Access to hearing assessment is important for children, as poor auditory information can lead to poor speech and oral language development. This study aims to identify enablers and barriers to accessing hearing assessments for Australian children from the perspective of speech-language pathologists (SLPs), comparing access in metropolitan, regional, and rural areas.

METHOD

This is a sequential, explanatory mixed-methods study. Forty-nine participants completed the quantitative survey and 14 participated in semi-structured interviews. The study was undertaken online and included participants from metropolitan, regional, and rural parts of Australian states and territories.

RESULT

Similar accessibility issues were experienced across geographic locations and access to hearing assessment was related to the complexity of individual contexts. Speech-language pathologists felt that awareness and knowledge of hearing loss was low in parents and health professionals. Participants discussed barriers such as long wait times, complex criteria, and inefficient services that lead to compromised outcomes for clients.

CONCLUSION

Barriers to hearing assessment are extensive and multifaceted. Future research might examine the accessibility of the health system in light of the barriers discussed in this research, and whether policies and procedures could be adapted to allow more easily accessible services.

An automatic diagnosis model of otitis media with high accuracy rate using transfer learning

Introduction: Chronic Suppurative Otitis Media (CSOM) and Middle Ear Cholesteatoma are two common chronic otitis media diseases that often cause confusion among physicians due to their similar location and shape in clinical CT images of the internal auditory canal. In this study, we utilized the transfer learning method combined with CT scans of the internal auditory canal to achieve accurate lesion segmentation and automatic diagnosis for patients with CSOM and middle ear cholesteatoma. Methods: We collected 1019 CT scan images and utilized the nnUnet skeleton model along with coarse grained focal segmentation labeling to pre-train on the above CT images for focal segmentation. We then fine-tuned the pre-training model for the downstream three-classification diagnosis task. Results: Our proposed algorithm model achieved a classification accuracy of 92.33% for CSOM and middle ear cholesteatoma, which is approximately 5% higher than the benchmark model. Moreover, our upstream segmentation task training resulted in a mean Intersection of Union (mIoU) of 0.569. Discussion: Our results demonstrate that using coarse-grained contour boundary labeling can significantly enhance the accuracy of downstream classification tasks. The combination of deep learning and automatic diagnosis of CSOM and internal auditory canal CT images of middle ear cholesteatoma exhibits high sensitivity and specificity.

PANEL 3: Otitis media animal models, cell culture, tissue regeneration & pathophysiology

OBJECTIVE

To review and summarize recently published key articles on the topics of animal models, cell culture studies, tissue biomedical engineering and regeneration, and new models in relation to otitis media (OM).

DATA SOURCE

Electronic databases: PubMed, National Library of Medicine, Ovid Medline.

REVIEW METHODS

Key topics were assigned to the panel participants for identification and detailed evaluation. The PubMed reviews were focused on the period from June 2019 to June 2023, in any of the objective subject(s) or keywords listed above, noting the relevant references relating to these advances with a global overview and noting areas of recommendation(s). The final manuscript was prepared with input from all panel members.

CONCLUSIONS

In conclusion, ex vivo and in vivo OM research models have seen great advancements in the past 4 years. From the usage of novel genetic and molecular tools to the refinement of in vivo inducible and spontaneous mouse models, to the introduction of a wide array of reliable middle ear epithelium (MEE) cell culture systems, the next five years are likely to experience exponential growth in OM pathophysiology discoveries. Moreover, advances in these systems will predictably facilitate rapid means for novel molecular therapeutic studies.

Otitis media: Interactions between host and environment, immune and inflammatory responses

OBJECTIVE

To review and highlight progress in otitis media (OM) research in the areas of immunology, inflammation, environmental influences and host-pathogen responses from 2019 to 2023. Opportunities for innovative future research were also identified.

DATA SOURCES

PubMed database of the National Library of Medicine.

REVIEW METHODS

Key topics were assigned to each panel member for detailed review. Search of the literature was from June 2019 until February 2023. Draft reviews were collated, circulated, and discussed among panel members at the 22nd International Symposium on Recent Advances in Otitis Media in June 2023. The final manuscript was prepared and approved by all the panel members.

CONCLUSIONS

Important advances were identified in: environmental influences that enhance OM susceptibility; polymicrobial middle ear (ME) infections; the role of adaptive immunity defects in otitis-proneness; additional genes linked to OM; leukocyte contributions to OM pathogenesis and recovery; and novel interventions in OM based on host responses to infection. Innovative areas of research included: identification of novel bacterial genes and pathways important for OM persistence, bacterial adaptations and evolution that enhance chronicity; animal and human ME gene expression, including at the single-cell level; and Sars-CoV-2 infection of the ME and Eustachian tube.

Influence of CX3CR1 Deletion on Cochlear Hair Cell Survival and Macrophage Expression in Chronic Suppurative Otitis Media

OBJECTIVE

Our objective was to determine whether the receptor CX3CR1 is necessary for the recruitment of macrophages to the cochlea in chronic suppurative otitis media (CSOM) and if its deletion can prevent hair cell loss in CSOM.

BACKGROUND

CSOM is a neglected disease that afflicts 330 million people worldwide and is the most common cause of permanent hearing loss among children in the developing world. It is characterized by a chronically discharging infected middle ear. We have previously demonstrated that CSOM causes macrophage associated sensory hearing loss. The receptor CX3CR1 is expressed on macrophages, which have been shown to be increased at the time point of outer hair cell (OHC) loss in CSOM.

METHODS

In this report, we examine the influence of CX3CR1 deletion (CX3CR1-/-) in a validated model of Pseudomonas aeruginosa (PA) CSOM.

RESULTS

The data show no difference in OHC loss between the CX3CR1-/- CSOM group and CX3CR1+/+ CSOM group (p = 0.28). We observed partial OHC loss in the cochlear basal turn, no OHC loss in the middle and apical turns in both CX3CR1-/- and CX3CR1+/+ CSOM mice at 14 days after bacterial inoculation. No inner hair cell (IHC) loss was found in all cochlear turns in all groups. We also counted F4/80 labeled macrophages in the spiral ganglion, spiral ligament, stria vascularis and spiral limbus of the basal, middle, and apical turn in cryosections. We did not find a significant difference in the total number of cochlear macrophages between CX3CR1-/- mice and CX3CR1+/+ mice (p = 0.97).

CONCLUSION

The data did not support a role for CX3CR1 macrophage associated HC loss in CSOM.