Evaluating the Role of Otologic Biomarkers to Differentiate Meniere's Disease and Vestibular Migraine

Expression of AQP8 in Serum of Patients With Meniere's Disease and Its Value in Evaluating the Degree of Hydrolabyrinth and Predicting Prognosis

OBJECTIVE

This study aims to explore the role of serum aquaporin 8 (AQP8) expression in evaluating the degree of hydrolabyrinth and predicting prognosis in patients with Meniere's disease.

METHODS

One hundred and five patients diagnosed with Meniere's disease in our hospital were enrolled in the Meniere's disease group. Another 102 healthy subjects were enrolled as the control group. The expression of serum AQP8 mRNA was determined by the quantitative real-time PCR (qRT-PCR) method. Receiver operating characteristic (ROC) curve analysis was carried out to analyse the predictive value of serum AQP8 mRNA expression for poor prognosis in Meniere's disease patients. Multivariate logistic regression was used to analyse the influencing factors of poor prognosis in patients with Meniere's disease.

RESULTS

The expression level of serum AQP8 mRNA in the Meniere's disease group was significantly higher than that in the control group (p < 0.05). In the severe hydrops group, serum AQP8 mRNA expression levels were higher than in the mild hydrops group and the no endolymphatic hydrops group. Additionally, the mild hydrops group had higher serum AQP8 mRNA levels than the no endolymphatic hydrops group (p < 0.05). The disease course, proportion of severe hydrops and serum AQP8 mRNA expression were all higher in the poor prognosis group compared to the good prognosis group (p < 0.05). The area under the curve (AUC) for serum AQP8 mRNA in predicting poor prognosis in Meniere's disease patients was 0.812 (95%CI: 0.702-0.922).

CONCLUSION

AQP8 mRNA is associated with the degree of hydrolabyrinth in patients with Meniere's disease and plays an important role in predicting prognosis.

Verification of Outer Hair Cell Motor Protein, Prestin, as a Serological Biomarker for Mouse Cochlear Damage

The motor protein prestin, found in the inner ear's outer hair cells (OHCs), is responsible for high sensitivity and sharp frequency selectivity in mammalian hearing. Some studies have suggested that prestin could be a serological biomarker for cochlear damage, as OHCs are highly vulnerable to damage from various sources. However, the reported data are inconsistent and lack appropriate negative controls. To investigate whether prestin can be used as a serological biomarker for cochlear damage or stress, we measured prestin quantities in the bloodstreams of mice using ELISA kits from different companies. Wildtype (WT) mice were exposed to different ototoxic treatments, including noise exposure and ototoxic reagents that rapidly kill OHCs. Prestin-knockout (KO) mice were used as a negative control. Our data show that some ELISA kits were not able to detect prestin specifically. The ELISA kit that could detect the prestin protein from cochlear homogenates failed to detect prestin in the bloodstream, despite there being significant damage to OHCs in the cochleae. Furthermore, the optical densities of the serum samples, which correlate to prestin quantities, were significantly influenced by hemolysis in the samples. In conclusion, Prestin from OHCs is not a sensitive and reliable serological biomarker for detecting cochlear damage in mice using ELISA.

Symptom networks analysis among people with Meniere's disease: Application for nursing care

Objectives

This study aimed to explore and visualize the relationships among multiple symptoms in patients with Meniere's disease (MD) and aid clinical nurses in the design of accurate, individualized interventions.

Methods

This study included 790 patients with MD at the Eye and ENT Hospital of Fudan University from October 2014 to December 2021. A self-designed symptom checklist was used to assess 15 MD-related symptoms and construct contemporaneous networks with all 15 symptoms in R software. Qgraph package and Fruchterman-Reingold layout were used for network visualization. Bootstrapping methods were performed to assess network accuracy and stability, and three centrality indices were adopted to describe relationships among symptoms.

Results

Symptom networks showed good accuracy and stability. "Anxiety and nervousness"(98.2%), "aural fullness"(84.4%) and "tinnitus"(82.7%) were the common symptom in MD patients, while "tinnitus", "aural fullness" and "decline in word recognition", were more serious. MD patients with longer disease duration had higher prevalence and severity for all symptoms (P < 0.05). Symptom networks showed good accuracy and stability. "Decline in word recognition," "fatigue," and "anxiety and nervousness" were at the center of the symptom networks, which had the largest strength values and closeness. "Decline in word recognition," "headache," and "spatial discrimination and poor orientation" were the symptoms with the highest betweenness with the strongest bridging effect. The ≥1-year disease group exhibited higher centralities for "drop attack" and "anxiety and nervousness," and a lower centrality for "headache" compared with the <1-year disease group.

Conclusions

The symptom networks of MD patients with varying disease durations were revealed. Clinicians and nurses must provide precision interventions tailored to modifying symptom severity and centrality. Nursing interventions should focus on word recognition issues and associated discomfort in MD patients with multiple symptoms.

Relationship of Serum Prestin Levels to the Severity of Sensorineural Hearing Loss

OBJECTIVE

Prestin is an outer hair cell (OHC) protein responsible for increasing cochlear sensitivity and has been proposed as a biomarker. We aimed to evaluate whether the serum prestin level is related to the severity of chronic sensorineural hearing loss (SNHL).

METHODS

Ninety subjects were recruited from the patient base at Samarra public hospitals and clinics in Iraq from January to October of 2022. They were divided into three groups equally: a group of healthy people without hearing loss (G0), a group with moderate SNHL (G1), and a group with severe SNHL (G2). The subjects ranged from 20 to 80 years of age and included 51 males and 39 females. Blood samples were collected, then serum was separated, and enzyme-linked immunosorbent assays were performed to quantify the levels of prestin.

RESULTS

Hearing thresholds were sequentially statistically higher across the three groups. While prestin levels were significantly higher in G1 and G2 than that in G0, there were no differences between the G1 and G2 levels. Serum prestin levels were positively correlated with hearing thresholds in G1, but not G2.

CONCLUSION

Our results suggest that in the clinical setting, prestin is sensitive to chronic mild to moderate SNHL (i.e., up to 40-60 dB), not more severe loss. This range is consistent with the added sensitivity provided by OHCs in the cochlea and provides support for prestin as a biomarker of OHC-mediated SNHL.

Automated Western Blot Analysis of Ototoxin-Induced Prestin Burst in the Blood after Cyclodextrin Exposure

HYPOTHESIS

Ototoxin cyclodextrin (CDX) will induce a burst in serum prestin when quantified with automated Western blot analysis.

BACKGROUND

In the clinical realm, we primarily rely on audiological measures for diagnosis and surveillance of sensorineural hearing loss (SNHL) and have limited therapeutic options. We have proposed a blood-based biomarker approach to overcome this challenge by measuring the outer hair cell's (OHC) electromotile protein, prestin, in the blood. Previously, we demonstrated a burst in serum prestin after cisplatin exposure using enzyme-linked immunosorbent assayELISA.

METHODS

Guinea pigs were treated with either 3,000 or 4,000 mg/kg CDX, and serum samples were obtained through 3 days after exposure. Serum prestin levels were quantified using automated blot analysis, western and hair cell counts were obtained.

RESULTS

Both 3,000 and 4,000 mg/kg resulted in robust OHC loss, although more variability was seen at the lower dose. Automated Western blot analysis demonstrated that the prestin profile after CDX exposure is different than baseline. Specifically, a new ~134- kDa band accounted for the prestin burst after ototoxin ablation of OHCs at both doses.

CONCLUSIONS

We reproduced the prestin burst seen after cisplatin administration using CDX. Automated Western blot western analysis revealed that a ~a ~ 134- kDa species of prestin is responsible for the burst. We suggest that the induced band may be a prestin dimer, which could serve as a biomarker for early detection of ototoxicity in the clinical setting. These results add further promise to the potential of serum prestin to serve as an ototoxicity biomarker when using therapeutics with ototoxic properties.

Vestibular migraine or Meniere's disease: a diagnostic dilemma

Meniere's disease (MD) represents one of the vertigo disorders characterized by triad symptoms (recurrent vertigo, fluctuating hearing loss, tinnitus or ear fullness). The diagnosis of MD relies on the accurate and detailed taking of medical history, and the differentiation between MD and vestibular migraine (VM) is of critical importance from the perspective of the treatment efficacy. VM is a highly prevalent vertigo condition and its typical symptoms (headache, vestibular symptoms, cochlear symptoms) mimic those of MD. Furthermore, the misdiagnosis in MD and VM could lead to VM patients mistakenly receiving the traumatic treatment protocol designed for MD, and sustaining unnecessary damage to the inner ear. Fortunately, thanks to the advances in examination technologies, the barriers to their differentiation are being gradually removed. These advances enhance the diagnostic accuracy of vertigo diseases, especially VM and MD. This review focused on the differentiation of VM and MD, with an attempt to synthesize existing data on the relevant battery of differentiation diagnosis (covering core symptoms, auxiliary tests [audiometry, vestibular tests, endolymphatic hydrops tests]) and longitudinal follow-up. Since the two illnesses are overlapped in all aspects, no single test is sufficiently specific on its own, however, patterns containing all or at least some features boost specificity.

A bibliometric and visualization study of Meniere's disease: Current status and global hotspots and emerging trends

BACKGROUND

Meniere's disease (MD) is a clinical condition characterized by endolymphatic hydrops. Persistent symptoms negatively affect patients mood, and the underlying etiology remains unclear. It is necessary to comprehensively understand the relevant publications, review the history and current status of research, and analyze hotspots and frontiers of research on MD.

METHODS

We retrieved literature on Meniere's disease from 2003 to 2022 from the Web of Science database and extracted the data. Data visualization and analysis was conducted using Cite Space, VOS viewer, an online web tool, and Microsoft Office Power Point 2019.

RESULTS

In total, 2847 publications were analyzed. The number of annual publications was relatively stable, with an accelerated upward trend over the past 5 years. The country with the most publications was USA (751, 26.38%), while the University of Munich contributed more publications than any other institution (117, 4.11%). The article titled "Diagnostic criteria for Meniere's disease" by Lopez-Escamez J et al in 2015 was the most cited and co-cited publication, and also had the top co-cited references with the strongest citation bursts. Naganawa S was the author with the most publications (85, 2.99%). The top 3 journals and co-cited journals were Otology Neurotology, Acta Oto Laryngologica, and Laryngoscope. Recently, the key theme words were "sensorineural hearing loss," "therapy," "intratympanic injection method," "vestibular-evoked myogenic potentials," "vestibular migraine," "magnetic resonance imaging," and "meniere's disease."

CONCLUSIONS

The US has the largest number of publications and research institutions, many European countries have high-quality journals, and Japan has the highest number of scholars. The international opinion on Meniere's disease is relatively uniform. The stepped-therapy for MD is scientific and clear. Intratympanic injection of steroids and intratympanic injection of gentamicin are commonly used, but steroids are considered safer. Saccular dysfunction may be more common in patients with MD than in those with utricular dysfunctions. It is worth paying attention to study the relationship between MD and vestibular migraine through headache. Progress in magnetic resonance imaging technology is still required for the imaging diagnosis of MD.

High Serum Levels of Otolin-1 in Patients With Benign Paroxysmal Positional Vertigo Predict Recurrence

Background

Otolin-1 is an inner ear-specific protein that is exclusively expressed in otoconia and vestibule and cochlea cells. Recent investigations reported that otolin-1 can cross the blood-labyrinthine barrier and that the levels in serum well-reflected otolith status. Serum otolin-1 levels in patients with benign paroxysmal positional vertigo (BPPV) are significantly elevated compared with healthy controls. We aimed to explore whether otolin-1 can also serve as a biomarker for predicting BPPV recurrence.

Method

Patients at our institution with new-onset of idiopathic BPPV between May, 2017 and May, 2018 were recruited and followed up for 2 years. All demographic data of the patients were collected, and serum levels of otolin-1 and other laboratory indicators were measured and compared according to the recurrence status.

Results

A total of 74 patients, who met the inclusion criteria were enrolled in this study, of which 27 (36.5%) patients had suffered one or more episodes of recurrence after undergoing canal repositioning treatments during the study. The serum levels of otolin-1 in patients with recurrent BPPV were significantly higher than those in patients without recurrent BPPV (363.9 vs. 309.8 pg/ml, p = 0.001). In multivariate analysis comparing the second to fourth quartiles (Q2–Q4) against the first quartile (Q1) of otolin-1, the level of otolin-1 in Q4 could significantly predict BPPV recurrence, and the odds ratio (OR) was elevated by approximately 812% (OR = 9.12; 95% confidence interval [CI]: 1.44–57.9; p = 0.019).

Conclusion

High serum levels of otolin-1 were associated with an increased risk of BPPV recurrence, and further investigation is required to confirm this association and clarify the exact mechanism.

Noise exposure levels predict blood levels of the inner ear protein prestin

Serological biomarkers of inner ear proteins are a promising new approach for studying human hearing. Here, we focus on the serological measurement of prestin, a protein integral to a human’s highly sensitive hearing, expressed in cochlear outer hair cells (OHCs). Building from recent nonhuman studies that associated noise-induced OHC trauma with reduced serum prestin levels, and studies suggesting subclinical hearing damage in humans regularly engaging in noisy activities, we investigated the relation between serum prestin levels and environmental noise levels in young adults with normal clinical audiograms. We measured prestin protein levels from circulating blood and collected noise level data multiple times over the course of the experiment using body-worn sound recorders. Results indicate that serum prestin levels have a negative relation with noise exposure: individuals with higher routine noise exposure levels tended to have lower prestin levels. Moreover, when grouping participants based on their risk for a clinically-significant noise-induced hearing loss, we found that prestin levels differed significantly between groups, even though behavioral hearing thresholds were similar. We discuss possible interpretations for our findings including whether lower serum levels may reflect subclinical levels of OHC damage, or possibly an adaptive, protective mechanism in which prestin expression is downregulated in response to loud environments.