ALBERT

Description:    Mechanisms underlying the unique survival property of human spiral neurons are yet to be explored. P75 (p75 NTR ) is a low affinity receptor for neurotrophins and is known to interact with Trk receptors to modulate ligand binding and signaling. Up-regulation of this receptor was found to be associated with apoptosis as well as with cell proliferation. Its distribution and injury-induced change in expression pattern in the cochlea have been mainly studied in rodents. There is still no report concerning p75 NTR in post-natal human inner ear. We analyzed, for the first time, p75 NTR expression in five freshly fixed human cochleae by using immunohistochemistry techniques, including myelin basic protein (MBP) as a myelin sheath marker and TrkB as the human spiral neuron marker, and by using thin optical sectioning of laser confocal microscopy. The inner ear specimens were obtained from adult patients who had normal pure tone thresholds before the surgical procedures, via a trans-cochlear approach for removal of giant posterior cranial fossa meningioma. The expression of p75 NTR was investigated and localized in the glial cells, including Schwann cells and satellite glial cells in the Rosenthal canal, in the central nerve bundles within the modiolus, and in the osseous spiral lamina of the human cochleae. The biological significance of p75 NTR in human cochlea is discussed. Content Type Journal Article Category Regular Article Pages 1-9 DOI 10.1007/s00441-012-1395-7 Authors Wei Liu, Department of Surgical Sciences, Section of Otolaryngology, Uppsala University Hospital, 751 85 Uppsala, Sweden Rudolf Glueckert, Department of Otolaryngology and University Clinics Innsbruck (TILAK), University of Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria Anders Kinnefors, Department of Otolaryngology, Uppsala University Hospital, 75185 Uppsala, Sweden Annelies Schrott-Fischer, Department of Otolaryngology, University of Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria Mario Bitsche, Division of Clinical and Functional Anatomy, Department of Anatomy, Histology and Embryology, University of Innsbruck, Muellerstr. 59, A 6020 Innsbruck, Austria Helge Rask-Andersen, Department of Otolaryngology, Uppsala University Hospital, 75185 Uppsala, Sweden Journal Cell and Tissue Research Online ISSN 1432-0878 Print ISSN 0302-766X