Stem cell transplantation for auditory nerve replacement

Abstract

The successful function of cochlear prostheses depends on activation of auditory nerve. The survival of auditory nerve neurons, however, can vary widely in candidates for cochlear implants and influence implant efficacy. Stem cells offer the potential for improving the function of cochlear prostheses and increasing the candidate pool by replacing lost auditory nerve. The first phase of studies for stem cell replacement of auditory nerve has examined the in vitro survival and differentiation as well as in vivo differentiation and survival of exogenous embryonic and tissue stem cells placed into scala tympani and/or modiolus. These studies are reviewed and new results on in vivo placement of B-5 mouse embryonic stem cells into scala tympani of the guinea pig cochleae with differentiation into a glutamatergic neuronal phenotype are presented. Research on the integration and connections of stem cell derived neurons in the cochlea is described. Finally, an alternative approach is considered, based on the use of endogenous progenitors rather than exogenous stem cells, with a review of promising findings that have identified stem cell-like progenitors in cochlear and vestibular tissues to provide the potential for auditory nerve replacement.

Bone marrow mesenchymal stem cells differentiate into urothelial cells and the implications for reconstructing urinary bladder mucosa

“…When cultured under specific microenvironmental factors, stem cells have the potential to transdifferentiate into corresponding mature cells (Blazejewska et al 2009;Altschuler et al 2008). This approach has also been applied to BMSCs (Coleman et al 2007).…”

The border between the central and the peripheral nervous system in the cat cochlear nerve: A light and scanning electron microscopical study

“…Understanding the structure and function of the CNSePNS border in the cochlear nerve is becoming increasingly relevant because of experimental auditory stem cell transplantation into the spiral ganglion (see e.g., Altschuler et al, 2008;Chen et al, 2007) in order to restore a functional auditory nerve after spiral ganglion cell degeneration (Bao and Ohlemiller, 2010;Shibata et al, 2010) or rupture of the nerve.…”

“…Recently, it has also gained clinical interest because of its relevance to nerve root disorders and regeneration. During development, nerve fibers cross the CNSePNS border in either direction (Berthold and Carlstedt, 1977b;O'Brien et al, 2001) whilst in mature animals, the border is a barrier to regenerating nerve fibers (Carlstedt, 1997;Fraher, 2000), an important issue given the possibility of neural stem cell transplantation into the PNS (see e.g., Altschuler et al, 2008). However, fibers may pass through the border after its removal and subsequent reimplantation of the root (Carlstedt, 1997) or after treatment with trophic factors (Fraher, 2000;Ramer et al, 2000).…”

Comparison of Three Types of Mesenchymal Stem Cells (Bone Marrow, Adipose Tissue, and Umbilical Cord-Derived) as Potential Sources for Inner Ear Regeneration

“…A wide range of stem/ multipotent progenitor cells have been tested for their capability to differentiate toward inner ear sensory cells in vitro and in vivo [3][4][5] . Several groups have shown the possibility of mouse embryonic stem cells (mESCs) to differentiate into hair cells 6,7 and auditory neuron-like cells [8][9][10][11] . Differentiation methods to induce hair cell-like cells from ESCs or induced pluripotent stem cells (iPSCs) seem to be effective but require great proficiency 6,7 .…”