Using funds raised by the Meniere’s Research Fund Inc., and more specifically, by Lachlan Cameron who ran the river Rhine in 2013, the Meniere’s Research Laboratory has built the first “Light Sheet Fluorescence Microscope” in Australia. This type of microscope allows the research team to virtually “section” through the inner ear, taking 1000s of high-resolution images which can then be re-constructed to produce a 3D image of the ear. The technique involves first making an ear ‘optically-transparent’ using chemicals, and then passing the inner ear tissue en bloc through a thin (5 micron) 2D sheet of laser light, which only illuminates a single 2D slice of the tissue at any one time, which can then be imaged using a high-resolution camera.
The team is currently using this camera to image the changes in the volume of endolymph in their experimental models of Endolymphatic Hydrops. Prior to using this microscope, they had to rely on either histological sections (i.e. physically slicing up the ear and then viewing each slice under a traditional microscope – which is both inaccurate with respect to the inner ear morphology, and laborious), or they had to use high-resolution Xray Micro-CT imaging (which produces similar results as those obtained by the light-sheet microscope, but was expensive to perform).
The new Light-Sheet Microscope will allow the team to more effectively investigate the causes of Endolymphatic Hydrops, and they are also hoping to incorporate techniques that will allow them to use ‘fluorescent biomarkers’ to quantify the biochemical changes that occur within the inner ear during endolymphatic hydrops development.
16 May 2013 – Emeritus Professor W P R Gibson AM resigned as President to become Secretary. Mr Leo Tutt was appointed President. By unanimous agreement of the Committee.
The 2013 Fund Raising Appeal was launched at the end of April 2013.
25 January 2013 – Dr Yasuhiro Chihara following completion of his two year appointment to the Meniere’s Research team, was farewelled prior to his departure to Japan and to an appointment in Singapore. He will be sadly missed as his contribution was greatly appreciated.
4 December 2012 – Several donors contributed to a scholarship fund to be named “The Bruce Kirkpatrick Meniere’s Research Scholarship Fund”. The annual award of a prize for the best essay on this research will be determined by a committee chaired by Emeritus Professor W P R Gibson AM.
27 January 2013 – Laboratory Research: The Ménière’s Research laboratory at The University of Sydney, headed by Dr Daniel Brown, was successful in landing a National Health & Medical Research Committee project grant award, for $307,000 to help them continue with their experimental animal work in the laboratory. Furthermore, the group’s collaborative research with Prof Ian Curthoys from the University of Sydney also landed a $300,000 “Garnett Passe & Rodney Williams Foundation” project grant. These grants will enable the Ménière’s research group to continue their research into the physiological mechanisms underlying the primary symptoms of Ménière’s. The group have already published 2 scientific papers in 2013, with 2 more currently under editorial review, and several more in the publication pipeline.
Brown DJ, Chihara Y, Curthoys IS, Wong Y, Bos M. 2013. Changes in cochlear function during acute endolymphatic hydrops development in guinea pigs. Hearing Research, 296, 96-106 Chihara Y, Wong Y, Curthoys IS, Brown DJ. 2013. The effect of systemic administration of desmopressin on cochlear function in guinea pigs. Acta Otolaryngologica, in publication.
This funding and publication success comes on the back of the group’s recent discovery and demonstration first, that the systemic anti-diuretic hormone vasopressin has little impact on cochlear and vestibular function in laboratory animals, and second, that abrupt changes in both cochlear and vestibular function occur during experiments designed to mimic the development of endolymphatic hydrops (the hallmark of Ménière’s Disease). This later research demonstrated episodes of hearing recovery along with vestibular dysfunction. Previous researchers had theorized that such an event would occur if the endolymphatic compartment of the inner ear ruptured with hydrops: the so called “Rupture theory” of Ménière’s vertigo attacks. However, the Ménière’s research team provided evidence that there is no rupture, but instead, the functional changes may be related to a sudden opening of physiological valves that separate the hearing organ (the cochlea) from the balance organ (the vestibular system). To visualize structural changes in the inner ear causing what the group believes to be similar to a Ménière’s vertigo attack, they used high resolution X-Ray imaging of the inner ear, along with a kind of dye to demonstrate conclusively that severe endolymphatic hydrops does not cause a rupture.
These results do at least two things for us; they provide a clearer picture of what is happening in a Ménière’s sufferer’s ear, and they also identify fundamental mechanisms in the ear that regulate endolymph volume, such as protein channels which open when the endolymphatic compartment swells. The group believes the pathology of these fluid regulation mechanisms is the cause of Ménière’s Disease. Now that they have a way of monitoring the function of these mechanisms in the ear when they are stressed, the next phase of the Ménière’s group’s research will be to test drugs and treatments aimed directly at manipulating these physiological mechanisms. This will hopefully provide an effective cure for endolymphatic hydrops and Ménière’s.
Clinical Trials: Over the last year and a half, the Ménière’s Research Laboratory at The University of Sydney has been investigating the feasibility of running a clinical trial to test if antiviral drugs can provide an effective treatment for Ménière’s symptoms. While the group still aims to perform such a trial, there have been several hurdles to overcome, primarily due to the difficulty and expense of running placebo-controlled drug trials such as these, particularly given the fluctuating nature of Ménière’s Disease which will ultimately require numerous sufferers to be treated, each over the course of a full year. The Ménière’s Research group is now looking for additional funding to engage the NHMRC Clinical Trials Centre to redesign and oversee the progress of the trial. For more information on the progress of the clinical trial, keep an eye on the Ménière’s Research Fund Inc. website, or contact Prof William Gibson or Dr Daniel Brown at The University of Sydney.
Dr Chihara: Dr Yasuhiro Chihara (or “Yas”) finished his 2 year sponsored work VISA contract with The University of Sydney at the end of January 2013, returning to Japan briefly with his wife Yoshie and 3 children (including 5 month old Yoshihro – born in Sydney) before he is expected to take up a new clinical position in Singapore. It has been an extremely fruitful 2 years with Dr Chihara at the Ménière’s laboratory, with the group already publishing several papers and with numerous more in the works. The Ménière’s laboratory will continue to collaborate with Dr Chihara for many years to come, as we wish him all the best for his new placement in Singapore.