Intratympanic Dexamethasone in the Treatment of Ménière's Disease: A Comparison of Two Techniques

In silico pharmacological study of AQP2 inhibition by steroids contextualized to Ménière's disease treatments

Ménière's disease (MD) is characterized by an abnormal dilatation of the endolymphatic compartment called endolymphatic hydrops and is associated with fluctuating hearing losses and vertigo. Corticosteroid treatment is typically administered for its anti-inflammatory effects to MD patients. However, we recently described for the first time a direct interaction of two corticosteroids (dexamethasone and cortisol) with human AQP2 which strongly inhibited water fluxes. From these initial studies, we proposed an AQPs Corticosteroids Binding Site (ACBS). In the present work, we tested the interaction of 10 molecules associated to the steroid family for this putative ACBS. We observed a wide diversity of affinity and inhibitory potential of these molecules toward AQP2 and discussed the implications for inner ear physiology. Among the tested compounds, cholecalciferol, calcitriol and oestradiol were the most efficient AQP2 water permeability inhibitors.

Bifenestral surgical and chemical labyrinthectomy, a new effective ablative surgical approach to intractable vertigo in Ménière Disease elderly Patients

INTRODUCTION

In this article, the bi-fenestral surgical chemical labyrinthectomy is introduced as a surgical demolition technique for treating resisting incurable forms of Meniere's disease in patients aged over 70 and/or with low hearing residues refractory to medical treatment.

MATERIALS AND METHODS

The results on participants fitting the inclusion criteria (n = 16) were reported using anamnesis (frequency of the crisis), Dizziness Handicap Inventory (DHI) and Functional Level Scale (FLS) before and after the intervention.

RESULTS

Vertigo control was achieved in all patients of this case series. A difference of 57 and 3.67 in mean DHI (from 68 (SD 16,7) to 11 (SD 14)) and FLS (from 4,68 (SD 0,7) to 0,1 (SD 0,3)) scores respectively were seen after an average of 16.28 months. Contextually tinnitus was reported to improve in seven patients (43,75%), aggravate in three (18,75%) and remain unchanged in the remaining six(37,5%).

CONCLUSION

Bi-fenestral surgical chemical labyrinthectomy appears a safe, immediate, and effective demolition treatment for vertigo control in a restricted class of patients affected by intractable Meniere disease.

A Perspective for Ménière’s Disease: In Silico Investigations of Dexamethasone as a Direct Modulator of AQP2

Ménière’s disease is a chronic illness characterized by intermittent episodes of vertigo associated with fluctuating sensorineural hearing loss, tinnitus and aural pressure. This pathology strongly correlates with a dilatation of the fluid compartment of the endolymph, so-called hydrops. Dexamethasone is one of the therapeutic approaches recommended when conventional antivertigo treatments have failed. Several mechanisms of actions have been hypothesized for the mode of action of dexamethasone, such as the anti-inflammatory effect or as a regulator of inner ear water homeostasis. However, none of them have been experimentally confirmed so far. Aquaporins (AQPs) are transmembrane water channels and are hence central in the regulation of transcellular water fluxes. In the present study, we investigated the hypothesis that dexamethasone could impact water fluxes in the inner ear by targeting AQP2. We addressed this question through molecular dynamics simulations approaches and managed to demonstrate a direct interaction between AQP2 and dexamethasone and its significant impact on the channel water permeability. Through compartmentalization of sodium and potassium ions, a significant effect of Na+ upon AQP2 water permeability was highlighted as well. The molecular mechanisms involved in dexamethasone binding and in its regulatory action upon AQP2 function are described.

[Topical drug administration to the inner ear. Modern state of the problem and development perspectives]

The work assessed modern methods of drug delivery through biological barriers to the lesion, in particular, through the most studied - skin. The main advantages and disadvantages of the existing methods for the topical administration of drugs into the inner ear - intra-imperial and intra-labyrinth delivery are analyzed. A brief review of medicinal substances for topical administration to the inner ear, both widely used (for example, aminoglycosides, steroid drugs) and undergoing clinical trials, is given. An assessment is made of the prospects for the use of transmembrane drug delivery to the inner ear using an electric field, which has a combined electro-creative and iontophoretic effect.

European Position Statement on Diagnosis, and Treatment of Meniere's Disease

Meniere Disease keeps challenges in its diagnosis and treatment since was defined by Prosper Meniere at the beginning of 19th Century. Several classifications and definition were made until now and speculations still exist on its etiology. As the etiology remains speculative the treatment models remain in discussion also. The European Academy of Otology and Neurotology Vertigo Guidelines Study Group intended to work on the diagnosis and treatment of Meniere's disease and created the European Positional Statement Document also by resuming the consensus studies on it. The new techniques on diagnosis are emphasized as well as the treatment models for each stage of the disease are clarified by disregarding the dilemmas on its treatment. The conservative, noninvasive and invasive therapeutic models are highlighted.

Future of Implantable Auditory Devices

The advances in technology leading to rapid developments in implantable auditory devices are constantly evolving. Devices are becoming smaller, less visible, and more efficient. The ability to preserve hearing outcomes with cochlear implantation will continue to evolve as surgical techniques improve with the use of continuous feedback during the procedure as well as with intraoperative delivery of drugs and robot assistance. As engineering methods improve, there may one day be a totally implantable aid that is self-sustaining in hearing-impaired patients making them indistinguishable from patients without hearing loss.

Intratympanic Therapies in Ménière Disease: Evaluation of Outcomes and Early Vertigo Control

OBJECTIVE

To evaluate outcomes of intratympanic (IT) dexamethasone and gentamicin in Ménière Disease (MD).

METHODS

Charts of adult patients with unilateral definite MD receiving IT gentamicin or dexamethasone from 2005 to 2017 were retrospectively reviewed. All patients had at least 6 months follow-up. Failure in each group was defined as the need for more aggressive therapy. Prior to 2011, all patient received IT gentamicin, administered as primary therapy after failure of conservative treatment measures. Gentamicin was administered every 2 weeks, up to three injections, until vertigo control was achieved. Beginning in 2011, the treatment protocol shifted to IT dexamethasone as initial treatment, with gentamicin used for dexamethasone failures. Dexamethasone was administered weekly for up to three injections. Treatments could be repeated if symptoms recurred.

RESULTS

Thirty-three patients received IT dexamethasone, and 70 patients received IT gentamicin. Dexamethasone patients received a mean of 3.3 injections compared to 2.7 in the gentamicin group (P = 0.011). There were 12 (38%) failures in the dexamethasone group and only seven (10%) gentamicin failures (P = 0.025). No patients failed both treatments. The mean time to failure in the dexamethasone group was 5 months, whereas in the gentamicin group it was 27 months. Change in pure tone audiometry from baseline was not different between treatment groups (P = 0.30).

CONCLUSION

Subjects receiving IT gentamicin required fewer injections and had a significantly longer time to failure than IT dexamethasone. Audiometric outcomes were similar between the groups. The use of IT gentamicin as initial therapy for early and long-term control of MD is safe and effective.

LEVEL OF EVIDENCE

3 Laryngoscope, 129:216-221, 2019.

RNA-sequencing study of peripheral blood mononuclear cells in sporadic Ménière's disease patients: possible contribution of immunologic dysfunction to the development of this disorder

To date, the pathogenesis of Ménière's disease (MD) remains unclear. This study aims to investigate the possible relationship between potential immune system-related genes and sporadic MD. The whole RNA-sequencing (RNA-seq) technology was used to analyse the transcriptome of peripheral blood mononuclear cells of three MD patients and three control individuals. Of 366 differentially expressed genes (DEGs), 154 genes were up-regulated and 212 genes were down-regulated (|log₂ fold change| > 1 and P < 0·05). Gene ontology (GO) enrichment analysis illustrated that immune relevant factors played a key role in the pathogenesis of MD. Of 366 DEGs, we focused upon analysing the possible immune-related genes, among which the significantly up-regulated genes [glutathione S-transferase mu 1 (GSTM1), transmembrane protein 176 (TMEM176)B, TMEM176A] and down-regulated genes [solute carrier family 4 member (SLC4A)10 and SLC4A1] especially drew our attention. The mRNA expression levels of GSTM1, TMEM176B, TMEM176A, SLC4A1 and SLC4A10 were analysed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The serum concentration of GSTM1, TMEM176B and SLC4A10 proteins were measured by enzyme-linked immunosorbent assay (ELISA). Considering the results of qRT-PCR and ELISA, it was noteworthy that GSTM1 exhibited the highest fold change between two groups, which was consistent with the deep sequencing results by RNA-seq. In conclusion, our study first offers a new perspective in MD development on the basis of RNA expression patterns, suggesting that immune factors might be involved in the MD pathogenesis. Remarkably, GSTM1 might be a possible candidate gene for the diagnostic biomarker of MD and provides the basis for further biological and functional investigations.