Affiliations: Department of Ophthalmology, Faculty of Medicine,
University of Szeged, Szeged, Hungary
Note: [] Corresponding author: Department of Ophthalmology, Faculty of
Medicine, Albert Szent-Györgyi Clinical Centre, University of Szeged, 6720
Szeged, Korányi fasor 10-11, Hungary. Tel.: +36 62 545786; Fax: +36 62
544573; E-mail: nogradi@opht.szote.u-szeged.hu
Abstract: Loss of spinal motoneurones results in severe functional impairment.
The most successful way to replace missing motoneurones is the use of embryonic
postmitotic motoneurone grafts. It has been shown that grafted motoneurones
survive, differentiate and integrate into the host cord. If grafted
motoneurones are provided with a suitable conduit for axonal regeneration (e.g.
a reimplanted ventral root) the grafted cells are able to grow their axons
along the whole length of the peripheral nerves to reach muscles in the limb
and restore function. Grafted motoneurones show excellent survival in
motoneurone-depleted adult host cords, but the developing spinal cord appears
to be an unfavourable environment for these cells. The long term survival and
maturation of the grafted neurones are dependent on the availability of a nerve
conduit and one or more target muscles, no matter whether these are ectopic
nerve-muscle implants or limb muscles in their original place. Thus, grafted and host motoneurones induce functional recovery of
the denervated limb muscles when their axons regenerate into an avulsed and
reimplanted ventral root. On the other hand, motoneurone-enriched embryonic
grafts placed into a hemisection cavity in the cervical spinal cord induce
axonal regeneration from great numbers of host motoneurones, possibly by the
bridging effect of the grafts. In this case the regenerating host motoneurones
reinnervate their original target muscles while the graft provides few axons
for the reinnervation of muscles. These results suggest that reconstruction of the injured spinal cord
with embryonic motoneurone-enriched spinal cord graft is a feasible method to
improve severe functional motor deficits.
