Dysregulation of immune response in otitis media

Pathophysiology-Informed Design of Negatively Charged Liposomes for Enhanced Antibiotic Delivery across the Intact Tympanic Membrane in Acute Otitis Media Treatment

Acute otitis media (AOM) is a leading cause of oral antibiotic prescriptions for children in the U.S., often resulting in systemic side effects and contributing to antibiotic resistance. Local delivery of antibiotics across an intact tympanic membrane (TM) to treat the infection in the middle ear is challenging due to the impermeable TM, which blocks most molecules via the outermost stratum corneum layer. Recent research has identified liposomes encapsulating antibiotics as a highly promising approach to overcoming the intact TM during AOM, demonstrating superior delivery efficiency. However, their design principles remain elusive, especially regarding the desirable surface charge. While previous research has identified positive surface charge as being more effective for crossing healthy stratum corneum, this study illustrates the opposite is true during infection. We compared hydrogel formulations containing positively and negatively charged liposomes in terms of their in vitro release, permeation across intact TM ex vivo, in vivo AOM treatment efficacy, and tissue-level biocompatibility using an established chinchilla model. Our results indicate that negatively charged liposomes outperformed positively charged ones, successfully eradicating 100% of AOM cases. We attributed this to interactions between the negatively charged liposomes and the immune response to infection. Specifically, the complement activation, which triggers neutrophils' phagocytosis, is enhanced in response to the negatively charged liposomes. Our findings highlight an opportunity to improve delivery efficiency by considering the pathophysiology more wholistically during the design of drug delivery vehicles.

The Role of Eustachian Tube Dysfunction in Recurrent Chronic Otitis Media: A Cross-Sectional Study of Anatomical and Functional Variations

Background/Objectives: Recurrent chronic otitis media (rCOM) is a major cause of hearing impairment, often linked to Eustachian tube (ET) dysfunction. Anatomical abnormalities, such as ET narrowing and obstructions, and functional impairments, including poor pressure regulation, play significant roles in rCOM recurrence. This study aimed to (1) identify anatomical variations of the ET in patients with rCOM using high-resolution imaging; (2) evaluate ET functional status using tympanometry, tubomanometry, and ET function tests; and (3) assess the correlation between anatomical variations and functional impairments in predicting rCOM recurrence. Methods: A cross-sectional study was conducted on 212 patients with rCOM and 212 controls. High-resolution CT and MRI were used to assess ET anatomy, while functional status was evaluated using tympanometry, tubomanometry, and Valsalva maneuver tests. Statistical analyses, including t-tests, Pearson correlation, and Cox proportional hazards models, were applied to examine the relationship between anatomical and functional impairments and rCOM recurrence. Results: Significant anatomical differences were observed in the rCOM group, including ET narrowing (24.53% vs. 11.32%, p = 0.014) and curvature (32.08% vs. 14.15%, p < 0.001). Functional impairments were also more prominent in rCOM patients, with higher ET opening pressure (120.56 ± 14.34 dPa vs. 85.78 ± 12.98 dPa, p < 0.001) and lower Valsalva maneuver success rates (62.32% vs. 89.56%, p < 0.001). Cox regression indicated that anatomical and functional impairments significantly predicted faster recurrence (HR for tympanometry peak pressure = 1.56, p < 0.001). Conclusions: The ETs anatomical and functional impairments are significant predictors of rCOM recurrence. A combined assessment of these factors can improve diagnostic accuracy and guide more targeted interventions to prevent recurrence.

A Systematic Review and Meta-Analysis of the Efficacy of Antimicrobial Chemoprophylaxis for Recurrent Acute Otitis Media in Children

OBJECTIVES

Acute otitis media (AOM) is a common childhood infection. Recurrent AOM affects a subset of children, resulting in an adverse impact on quality of life, socioeconomic disadvantage, and risk of long-term sequelae. Antimicrobial chemoprophylaxis is used in some settings but is increasingly controversial due to an awareness of adverse long-term effects and contribution to global antibiotic resistance.

DESIGN AND SETTING

A comprehensive literature search was undertaken using Medline (1946-October 2023) and Embase (1974-October 2023). The primary aim was to assess the efficacy of antimicrobial chemoprophylaxis on AOM episodes in children < 18 years of age. Bias and quality assessment was performed. Dichotomous data were analysed using risk ratio with 95% confidence intervals. Meta-analysis was carried out using random-effects models for pooled analysis, independent of heterogeneity. Heterogeneity was assessed using the I 2 statistic.

MAIN OUTCOME MEASURES

The effect of antimicrobial chemoprophylaxis in children with rAOM on the number of individual AOM episodes.

SECONDARY OUTCOMES

assessment of antimicrobial agents and outcomes in children with risk factors.

RESULTS

Assessment of qualitative data was performed on 20 studies (n = 2210). No controlled trials were identified post-multivalent pneumococcal conjugate vaccine (PCV) introduction, restricting current generalisability. Quantitative meta-analysis on nine pre-PCV studies (n = 1087) demonstrated antimicrobial chemoprophylaxis reduced any episode of AOM with a risk ratio 0.59 (95% CI 0.45-0.77).

CONCLUSION

Families and clinicians must balance marginal short-medium term benefit (based on pre-PCV data), and the potential for adverse effects to that individual, and the societal risk of antimicrobial resistance with prolonged antibiotic use.

Mapping Human Immunity and the Education of Waldeyer's Ring

The development and deployment of single-cell genomic technologies have driven a resolution revolution in our understanding of the immune system, providing unprecedented insight into the diversity of immune cells present throughout the body and their function in health and disease. Waldeyer's ring is the collective name for the lymphoid tissue aggregations of the upper aerodigestive tract, comprising the palatine, pharyngeal (adenoids), lingual, and tubal tonsils. These tonsils are the first immune sentinels encountered by ingested and inhaled antigens and are responsible for mounting the first wave of adaptive immune response. An effective mucosal immune response is critical to neutralizing infection in the upper airway and preventing systemic spread, and dysfunctional immune responses can result in ear, nose, and throat pathologies. This review uses Waldeyer's ring to demonstrate how single-cell technologies are being applied to advance our understanding of the immune system and highlight directions for future research.

17β-estradiol Attenuates the Middle Ear Inflammatory Response to Nontypeable Haemophilus influenzae

OBJECTIVES

17β-estradiol (E2) is a steroidal hormone with immunomodulatory functions that play a role in infectious and inflammatory diseases. E2 was recently identified as the leading upstream regulator of differentially expressed genes in a comparative RNA sequencing study of pediatric patients with otitis media (OM) versus OM-free counterparts and may therefore play a role in the inflammatory response to bacterial otopathogens during pediatric OM. This study examined the effect of E2 on bacterial-induced inflammatory cytokine expression in an in vitro pediatric OM model.

METHODS

An immortalized middle ear (ME) epithelial cell line, ROM-SV40, was developed from a pediatric recurrent OM patient. The culture was exposed to E2 at physiological levels for 1-48 h prior to 6 h-stimulation with nontypeable Haemophilus influenzae (NTHi) whole cell lysate. TNFA, IL1B, IL6, and IL8 were assayed by qPCR and ELISA.

RESULTS

E2 pretreatment (24 h) abrogated NTHi induction of IL6; a longer pretreatment (1-10 nM, 48 h) abrogated IL1B induction (p < 0.05). E2 pretreatment (5 nM, 48 h) abrogated NTHi-induced IL8 secretion (p = 0.017).

CONCLUSION

E2 pretreatment partially rescued NTHi-induced cytokine production by ME epithelia. These data support a role for E2 in moderating the excessive inflammatory response to middle ear infection that contributes to OM pathophysiology.

LEVELS OF EVIDENCE

NA Laryngoscope, 134:3815-3819, 2024.

A semi-quantitative visual lateral flow immunoassay for SARS-CoV-2 antibody detection for the follow-up of immune response to vaccination or recovery

The lateral flow immunoassay (LFIA) technique is largely employed for the point-of-care detection of antibodies especially for revealing the immune response in serum. Visual LFIAs usually provide the qualitative yes/no detection of antibodies, while quantification requires some equipment, making the assay more expensive and complicated. To achieve visual semi-quantification, the alignment of several lines (made of the same antigen) along a LFIA strip has been proposed. The numbering of the reacting lines has been used to correlate with the quantity of some biomarkers in serum. Here, we designed the first semiquantitative LFIA for detecting antibodies and applied it to classify the immune response to SARS-CoV-2 raised by vaccination or natural infection. We used a recombinant spike receptor-binding domain (RBD) as the specific capture reagent to draw two test lines. The detection reagent was selected among three possible ligands that are able to bind to anti-spike human antibodies: the same RBD, staphylococcal protein A, and anti-human immunoglobulin G antibodies. The most convenient detector, adsorbed on gold nanoparticles, was chosen based on the highest correlation with an antibody titre of 171 human sera, measured by a reference serological method, and was the RBD (Spearman's rho = 0.84). Incorporated into the semiquantitative LFIA, it confirmed the ability to discriminate high- and low-titre samples and to classify them into two classes (Dunn's test, P < 0.05). The proposed approach enabled the semiquantification of the immune response to SARS-CoV-2 by the unaided eye observation, thus overcoming the requirement of costly and complicated equipment, and represents a general strategy for the development of semiquantitative serological LFIAs.

Association of iron deficiency with chronic suppurative otitis media in adults

BACKGROUND

Chronic suppurative otitis media (CSOM) is a prevalent chronic inflammatory disease globally. Current research suggests a possible association between anaemia and the development of CSOM.

OBJECTIVES

The objective of this trial was to investigate the relationship between iron metabolism and chronic suppurative otitis media (CSOM) in adults aged 20-60 years.

MATERIALS AND METHODS

A consecutive sampling case-control study was used. The study participants were divided into a case group (42 children diagnosed with CSOM) and a control group (42 children with normal ears). Haemoglobin (Hb), Hematocrit (Hct), mean corpuscular volume of erythrocytes (MCV), serum iron level (SI), unsaturated iron-binding capacity (UIBC), total iron-binding capacity (TIBC), transferrin (TF), ferritin (Fer) were tested in all the participants, and the results were compared with the normal ranges of the World Health Organization (WHO). The comparative analysis of cases and controls was performed using the Fisher extract test, independence t-test, or Mann-Whitney U test. p-value <.05 was considered statistically significant for correlation.

RESULTS

There were 61 patients with CSOM and 61 controls included in the study. In the case group, 16 out of 61 patients (26.2%) had low ferritin levels and in the control group, 1 out of 61 patients (1.6%) had low ferritin levels (p < .001). In the case group, 6 (9.8%) of 61 patients had IDA, and in the control group, there were no patients with IDA among 61 patients (p = .027). There were significant differences in SI, UIBC, and Fer parameters between the groups.

CONCLUSIONS

In adult patients, the incidence of iron deficiency was higher in CSOM patients than in controls. Iron deficiency may be considered a potential risk factor for chronic suppurative otitis media, and serum iron parameters should be evaluated in these CSOM patients and further studies should be conducted to better understand the potential link between iron deficiency and CSOM.

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.

Recurrent Acute Otitis Media Could Be Related to the Pro-Inflammatory State That Causes an Incorrect Diet

Introduction: Acute Otitis Media (AOM) is the most commonly-occurring bacterial complication in childhood. After making certain corrections to the patients’ dietary habits, which we found to be excessively high in animal-based and industrially-processed foods, we observed a significant reduction in recurrent colds and their bacterial complications. We promote an original way of treating these diseases, since until now the conventional treatment is based on pharmacological and surgical treatment. From our point of view, the mucosa that covers the entire ENT area is in a pro-inflammatory and hyper-reactive state, as a consequence of the alterations produced by an inadequate diet. For us there is no difference in the nutritional treatment of the different mucous membranes that cover the ENT area. The purpose of the study was to assess the effects of the Traditional Mediterranean Diet (TMD) on patients diagnosed with Recurring Acute Otitis Media (RAOM). Methods: prospective pre-postest comparison study with 48 girls and 42 boys aged 1–5 years, each of whom had been and included on the 1-year programme “Learning to eat the Mediterranean Way”, designed to encourage the adoption of the TMD. We studied clinical and therapeutic variables and various anthropometric parameters. Results: all the symptomatic indicators studied (number and intensity of episodes of otitis and emergency admissions) showed a positive and statistically significant evolution in RAOM. By the end of the study, none of the patients met the criteria for classification as RAOM, and 60% percent of patients did not present any further episodes of AOM. In line with the above, the use of anti-microbial drugs and symptomatic treatments reduced considerably; the use of antibiotics dropped from 4.30 occasions/patient/year, to 0.66 (p < 0.001), and the used of symptomatic treatments dropped from 7.63 to 2.75 (p < 0.001). The level of family satisfaction was very high. Conclusions: the adoption of the Traditional Mediterranean Diet has been demonstrated to significantly reduce occurrence of acute otitis media and may contribute to the treatment of patients diagnosed with recurrent acute otitis media.

Evaluation of Caspase-1, Interleukin-1β, and Interleukin-18, in the Middle Ear Effusion in Children With Otitis Media With Effusion

Objectives: The present study aimed to assess the expression of caspase-1 and caspase-1-dependent processing of cytokines, such as interleukin (IL)-1β and IL-18, in the middle ear effusion of children with otitis media with effusion (OME) in order to identify the potential role of inflammasomes in OME. Methods: This study included 29 children scheduled for myringotomy with the insertion of tympanostomy tubes due to OME. Middle ear effusion (MEE) was collected during the surgery. Caspase-1, IL-1β, and IL-18 were assayed using enzyme-linked immunosorbent assay kits. The levels were compared between those with mucoid and serous MEE and those with and without a history of ventilation tube insertion. Results: Caspase-1, IL-1β, and IL-18 were detected in all samples. The caspase-1, IL-1β, and IL-18 levels did not significantly differ between mucoid samples and serous samples. No statistical significances were discovered in caspase-1, IL-1β, and IL-18 levels between with and without a history of ventilation tube groups. There was a significant negative correlation between IL-1β and IL-18 and the duration of OME (p < 0.05). However, no significant correlation was found between caspase-1 and disease duration. Conclusions: Inflammasomes may participate in the inflammatory process of OME. IL-1β and IL-18 levels in the MEE decreased over time.