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In Vitro Growth of Human Endolymphatic Sac Cells: A Transmission Electron Microscopic and Immunohistochemical Study in Patients with Vestibular Schwannoma and Ménière's Disease

Hypothesis Human endolymphatic sac cells have been notoriously difficult to maintain in culture. It was hypothesized that an in vitro environment intended for growth of keratinocytes would also be suitable for human endolymph sac cells. Background Studies on cell physiology of human endolymphatic sac cells have been hampered by difficulties in maintaining them in culture. Methods Human endolymphatic sac cells were taken from 10 patients during translabyrinthine skull base surgery for vestibular schwannoma, one of whom also had Ménière's disease. Cell lines of proliferating epithelial cells were obtained after trypsinization and growth in a 3:1 mixture of Dulbecco's modified Eagle medium and Ham's F12 medium supplemented with 10% fetal calf serum. Fibroblast overgrowth was counteracted by the use of so-called cloning rings. During various stages, cells were investigated with transmission electron microscopy and/or immunohistochemistry. Results Proliferation took place after 2 to 3 days of primary cell culture. The cells were cytokeratin-positive and pleomorphic, and they had abundant polarized microvillus-like projections, numerous coated cytoplasmic pits and vesicles, and a well-developed rough endoplasmic reticulum. Conclusion Cell lines of proliferating human endolymphatic sac cells can be produced with the technique described here and may be a valid tool in studies of human endolymph sac physiology.