Stria vascularis and vestibular dark cells: characterisation of main structures responsible for inner-ear homeostasis, and their pathophysiological relations

Ciuman, Raphael Richard

doi:10.1017/s0022215108002624

Cited by 62 publications

(56 citation statements)

References 165 publications

(167 reference statements)

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“…(Hibino and Kurachi, 2006) 2) The ionic currents are present within the endolymph, with no leakage. Although marginal cells, transition cells and even epithelial cells may have a role in the maintenance of potassium balance (150 mM) in the endolymph, the current is assumed to come from specific dedicated dark cells located adjacent to the macula structures (Kimura, 1969;Ciuman, 2009). 3) The current flow is local to the structures themselves and is balanced.…”

Section: The Modelsmentioning

confidence: 99%

Magnetic field effects on the vestibular system: calculation of the pressure on the cupula due to ionic current-induced Lorentz force

Antunes

Glover

et al. 2012

Phys. Med. Biol.

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A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. AbstractLarge static magnetic fields may be employed in magnetic resonance imaging (MRI). At high magnetic field strengths (usually from about 3 tesla and above) it is possible for humans to perceive a number of effects. One such effect is mild vertigo. Recently, Roberts et al (Current Biology 21:1635-1640 2011) proposed a Lorentz-force mechanism resulting from the ionic currents occurring naturally in the endolymph of the vestibular system. In the present work a more detailed calculation of the forces and resulting pressures in the vestibular system is carried out using a numerical model. Firstly, realistic 3D finite element conductivity and fluid maps of the utricle and a single semi-circular canal containing the current sources (dark cells) and sinks (hair cells) of the utricle and ampulla were constructed. Secondly, the electrical current densities in the fluid are calculated. Thirdly, the developed Lorentz force is used directly in the Navier-Stokes equation and the trans-cupular pressure is computed. Since the driving force field is relatively large in comparison with the advective acceleration, we demonstrate that it is possible to perform an approximation in the Navier-Stokes equations that reduces the problem to solving a simpler Poisson equation. This simplification allows rapid and easy calculation for many different directions of applied magnetic field. At 7 tesla a maximum cupula pressure difference of 1.6 mPa was calculated for the combined ampullar (0.7 A) and utricular (3.31 A) distributed current sources, assuming a hair-cell resting current of 100 pA per unit. These pressure values are up to an order of magnitude lower than those proposed by Roberts et al using a simplistic model and calculation, and are in good agreement with the estimated pressure values for nystagmus velocities in head rotation/caloric experiments. This modeling work supports the hypothesis that the Lorentz force mechanism is a significant contributor to the perception of magnetic field induced vertigo.

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Section: The Modelsmentioning

confidence: 99%

Magnetic field effects on the vestibular system: calculation of the pressure on the cupula due to ionic current-induced Lorentz force

Antunes

Glover

et al. 2012

Phys. Med. Biol.

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“…This structure may play a role in endolymph volume regulation and be a cause of the lengthy permanence of the GD in the ESp-SM in MD patients [Salt and Rask-Andersen, 2004]. The approach utilized in the present study may also have the advantage over the perilymphatic routes of directly reaching the stria vascularis and vestibular dark cells, the two main structures responsible for endolymph secretion [Ciuman, 2009]. Future research may adopt this route to investigate and treat disorders of inner ear homeostasis related to these two structures.…”

Section: Discussionmentioning

confidence: 95%

Evidence of Gadolinium Distribution from the Endolymphatic Sac to the Endolymphatic Compartments of the Human Inner Ear

Colletti

Mandalà²,

Carner³

et al. 2010

Audiol Neurotol

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To verify whether injection of substances into the endolymphatic sac (ES) diffuses into the endolymphatic compartments of the human inner ear and in particular to the endolymphatic space of the scala media (ESp-SM), as demonstrated in animals, an exploratory investigation with magnetic resonance imaging (MRI) and intraoperative electrocochleographic recordings (ECoG) was conducted in patients with Ménière’s disease (MD) treated with ES decompression. A mixture of dexamethasone and gadolinium (GD) in solution was injected into the ES of 4 patients. The results of the ES injection procedure were compared with administration of the same solution intratympanically (IT, 1 patient) and via a platinotomy in 2 patients. The study was conducted retrospectively at a tertiary referral center. Main outcomes measures were pre- and postintervention complete audiological and neuro-otological evaluation; intraoperative ECoG investigation with evaluation of the morphology of acoustically elicited compound action potentials (CAPs) and 1.5 T MRI evaluations at different follow-up times. Distribution of GD from the ES injection procedure was observed first in the ES, after 24 h in the vestibule and semicircular canals, and after 24–48 h in the ESp-SM in all patients. High signal was detected within the inner ear for 1 week or more (mean: 10 days; range: 7–16 days). Changes in morphology and latency of CAPs were observed within 30 min of the dilatory injection into the ES in all patients. Administration of GD into the vestibule and the IT approach did not distribute the contrast in the ES and GD was observed in the perilymphatic space of the vestibule, cochlea and semicircular canals. No side effects relating to administration of GD into the ES, IT or into the vestibule were observed. To the best of our knowledge this is the first demonstration in humans that drugs injected into the endolymphatic structure of the ES diffuse to the cochlea, presumably into the ESp-SM. The possibility of injecting substances into the endolymphatic space might open up new prospects in the treatment of inner ear disorders. Further studies will be needed to define the limitations of this approach.

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“…Cochlear ionic transport is very sensitive to pH variation: the endocochlear potential may be reduced by an acidification of pH and this could be responsible of a sudden inner-ear dysfunction and hearing loss. 65 According to the data in the literature, endocochlear ions that could be involved in this pathological mechanism, might include the following: K + /Na + ; [28][29][30] Fe 2+ ; [13][14][15]30 Ca 2+ /Mg 2+ ; 34,38 and Cl -. 39 …”

Section: Pathophysiology Of Ssnhl and Inner-ear Electrolytic Disordersmentioning

confidence: 99%

Sudden sensorineural hearing loss: Is there a connection with inner ear electrolytic disorders? A literature review

Ciorba

Corazzi

Bianchini

et al. 2016

Int J Immunopathol Pharmacol

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Electrolytic disorders of the inner ear represent a model that could be implicated in partially explaining the pathogenesis of sudden sensorineural hearing loss (SSNHL). Different types of electrolytes and different inner-ear loci are involved in cochlear homeostasis physiologically, to ensure the maintenance of an ion-balanced cochlear environment allowing a normal hair cell function. It has been hypothesized that a sudden loss of endocochlear potential, due to a rapid disruption of the inner ear fluid osmolality, could be responsible for a deterioration of the hearing function caused by damaged hair cells. The aim of this paper was to review the current literature and identify sources which might validate/fortify the hypothesis that inner ear electrolytic disorders have a role in the etiopathogenesis of SSNHL. The data in the literature underline the importance of ionic homeostasis in the inner ear, but they do not support a direct link between SSNHL and electrolyte disorders/imbalances. There is marginal evidence from otoacoustic emissions research that an indirect link might be present.

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Stria vascularis and vestibular dark cells: characterisation of main structures responsible for inner-ear homeostasis, and their pathophysiological relations

Cited by 62 publications

References 165 publications

Magnetic field effects on the vestibular system: calculation of the pressure on the cupula due to ionic current-induced Lorentz force

Magnetic field effects on the vestibular system: calculation of the pressure on the cupula due to ionic current-induced Lorentz force

Evidence of Gadolinium Distribution from the Endolymphatic Sac to the Endolymphatic Compartments of the Human Inner Ear

Sudden sensorineural hearing loss: Is there a connection with inner ear electrolytic disorders? A literature review

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