Other options for cell regeneration are bone-marrowderived
cells, which can differentiate into neurons and
pancreatic islet cells [65,66]. The introduction of bonemarrow-
derived stromal cells into the chinchilla inner ear,
albeit without preselection for inner-ear progenitors,
resulted in the upregulation of neural and glial markers
[46]. Bone marrow from the recipient patient could be
obtained from a biopsy, enabling an autologous transplant
that would not require immunosuppression, a technique
that has been used with myoblasts for cell transplantation
in the heart [67]. Moreover, bone-marrow-derived stem
cells are fully renewable and could provide adequate cell
numbers for transplantation. An alternative option for
autologous transplantation could be provided by the
nuclear transfer of a somatic cell nucleus to an enucleated
oocyte, to generate ES cells from an in vitro-generated
blastocyst [68]. Inner-ear cells made from such ES cells
would be fully compatible with the donor. These approaches
have yet to be undertaken for inner-ear cells, but might be
required for the development of therapeutic techniques to
be used in human patients.