In vitro growth of human endolymphatic sac cells: A transmission electron microscopic and immunohistochemical study in patients with vestibular schwannoma and Meniere's disease

Hypothesis: Human endolymphatic sac cells have been notoriously difficult t o maintain in culture. It was hypothesized that an in vitro environment int ended for growth of keratinocytes would also be suitable for human endolymp h sac cells. Background: Studies on cell physiology of human endolymphatic sac cells hav e been hampered by difficulties in maintaining them in culture. Methods: Human endolymphatic sac cells were taken from 10 patients during t ranslabyrinthine skull base surgery for vestibular schwannoma, one of whom also had Meniere's disease. Cell lines of proliferating epithelial cells we re 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 clon ing 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 abundan t 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 b e produced with the technique described here and may be a valid toot in stu dies of human endolymph sac physiology.