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Axon Morphology Changes in Peripheral Cochlear Nerve Axons Due to Vestibular Schwannoma

(2017) Eggink, M.C.

Sporadic vestibular schwannoma (VS) are the most common tumor within the cerebellopontine angle (CPA). VS patients present with sensorineural hearing loss in 95% of the cases, however the exact mechanism behind this is unknown. The theory of mechanical compression of the cochleovestibular nerve within the internal auditory canal (IAC) cannot fully account for this hearing loss. A recent theory postulates the secretion of molecules and extracellular vesicles by the tumor, shown to decrease the amount of spiral ganglion cell-bodies (SGCs) and hair cells in the cochlea. The morphology and therefore possible effect of these secretions on the peripheral nerve fibers in the osseous spiral lamina (OSL) has yet to be examined. A better understanding of the underlying pathology could lead to new therapies and treatment strategies for patients with VS. For this study, histopathologic slides from the human temporal bone archive of the Massachusetts Eye and Ear Infirmary (MEEI) were analyzed to quantify the density of the fibers in the OSL of 7 patients with sporadic and untreated VS, and 1 control. The density was found to be significantly lower on the side ipsilateral to the tumor than on the unaffected, contralateral side (p<0.01). A (p<0.01)larger tumor volume was correlated with a lower density , consistent with tumor compression of the cochlear nerve and/or a volume-related secretion of In conclusion, this study confirms the existence of cochlear pathology in neurotoxins.VS patients, with possible implications for cochlear implantation. This novel study required a method development, which posed clear limitations. Further studies should be done in a larger cohort, with specific staining of nerve fibers for more accurate quantification and analysis of the morphology.





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ID 3563
Moeder ID 3463
Volgorde Eggink, M.C.
Naam EgginkMC
Publiceren yes
OAI-naam Student_thesis
Path root/geneeskunde/2017/EgginkMC/
Gemaakt op: 2017-08-28 14:32:59
Gemodificeerd op: 2017-08-28 14:32:59
Digitaal ID 59a4299c0efb7
Afstudeerrichting opleiding/afstudeerrichting 1
Studierichting Studierichting 1
Titel Axon Morphology Changes in Peripheral Cochlear Nerve Axons Due to Vestibular Schwannoma
Ruilverkeer mogelijk no
Printen in opdracht no
Aantal pagina's 34
Publicatiejaar 2017
Taal en
Engelse samenvatting Sporadic vestibular schwannoma (VS) are the most common tumor within the cerebellopontine angle (CPA). VS patients present with sensorineural hearing loss in 95% of the cases, however the exact mechanism behind this is unknown. The theory of mechanical compression of the cochleovestibular nerve within the internal auditory canal (IAC) cannot fully account for this hearing loss. A recent theory postulates the secretion of molecules and extracellular vesicles by the tumor, shown to decrease the amount of spiral ganglion cell-bodies (SGCs) and hair cells in the cochlea. The morphology and therefore possible effect of these secretions on the peripheral nerve fibers in the osseous spiral lamina (OSL) has yet to be examined. A better understanding of the underlying pathology could lead to new therapies and treatment strategies for patients with VS. For this study, histopathologic slides from the human temporal bone archive of the Massachusetts Eye and Ear Infirmary (MEEI) were analyzed to quantify the density of the fibers in the OSL of 7 patients with sporadic and untreated VS, and 1 control. The density was found to be significantly lower on the side ipsilateral to the tumor than on the unaffected, contralateral side (p<0.01). A (p<0.01)larger tumor volume was correlated with a lower density , consistent with tumor compression of the cochlear nerve and/or a volume-related secretion of In conclusion, this study confirms the existence of cochlear pathology in neurotoxins.VS patients, with possible implications for cochlear implantation. This novel study required a method development, which posed clear limitations. Further studies should be done in a larger cohort, with specific staining of nerve fibers for more accurate quantification and analysis of the morphology.
Nederlandse samenvatting Eenzijdige vestibulaire schwannomen (VS) zijn de meest voorkomende tumoren van de brughoek. In 95% van de gevallen presenteert de patiënt zich met perceptief gehoorverlies maar het precieze mechanisme hiervan is niet bekend. De lang geldende consensus over gehoorverlies door mechanische druk van de tumor op de vestibulocochleaire zenuw binnen de inwendige gehoorgang, kan het patroon van gehoorverlies niet volledig verklaren. Recent onderzoek wijst naar tumorsecreties die schade veroorzaken in de spirale ganglion cellichamen (SGCs) en haarcellen van de cochlea. De morfologie van perifere uitlopers in the lamina spiralis ossea (OSL) is echter nog niet eerder geanalyseerd, wat waardevol kan zijn voor het ontwikkelen van nieuwe therapieën. Voor deze studie is de dichtheid van vezels in de OSL geanalyseerd in 7 patiënten, met eenzijdige onbehandelde VS, en 1 controle, geselecteerd uit het os temporale archief van de Massachusetts Eye and Ear Infirmary (MEEI). De dichtheid was significant lager aan de ipsilaterale kant dan aan de onaangedane, contralaterale kant (p<0.01). Een groter tumor volume werd gecorreleerd met lagere dichtheden (p<0.01), wat kan wijzen op tumor compressie van de nervus vestibulocochlearis of een volume-afhankelijke afscheiding van tumorsecreties. Concluderend bevestigt deze studie de aanwezigheid van cochleaire pathologie in patiënten met een VS. Door de noodzaak om een nieuwe methode te ontwikkelen, zijn er veel beperkingen aan de studie. Een toekomstige studie met een groter cohort en specifieke kleuringen naar zenuwvezels, kan hopelijk meer uitsluitsel geven over de precieze aantallen en morfologie van de perifere uitlopers in de OSL.
Onderwijsinstelling Medical Sciences
Type embargo abstract openbaar, scriptie op aanvraag
Auteur(s) Eggink, M.C.
UMCG begeleider(s) Faculty supervisor:; Free, dr. R.H. MD, ENT UMCG; GIPS-M supervisor:; Kallenberg, professor C.G.M. chairman GIPS-M
Begeleider(s) opleidingsinstelling External supervisor:; Stankovic, Professor K. MMD, PhD, FACS, ENT MEEI; Stankovic Laboratory,; Massachusetts Eye and Ear Infirmary, Boston USA
Auteur(s) Eggink, M.C.
UMCG begeleider(s) Faculty supervisor:; Free, dr. R.H. MD, ENT UMCG; GIPS-M supervisor:; Kallenberg, professor C.G.M. chairman GIPS-M


 
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