John van Geest Centre for Brain Repair

School of Clinical Medicine



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What is Brain Repair?

Repairing the structure of the brain and spinal cord

Replacing lost neurons

1) Where neurons are permanently lost, there are two potential ways of replacing them. The first is to transplant equivalent neurons taken from a donor brain or spinal cord. The second is to persuade primitive stem cells, which are present in the adult brain or can be transplanted, to turn into new neurons.

Neural transplantation. If a group of neurons are lost, an obvious possibility is to transplant new neurons in their place. This is particularly attractive in diseases such as Parkinson’s disease, in which the lost neurons are all in a small restricted site. Successful neuronal transplantation has not been achieved using neurons from adult donors. However, if neurons are taken from embryos of just the right age, they will survive transplantation. In addition they will grow nerve fibres into the host brain and make functional synaptic connections. In animal models of Parkinson’s disease this cures most of the symptoms of the disease. This has led to several trials of neuronal transplantation using embryonic tissue for human patients with Parkinson’s disease. In almost all these trials the patients have had their disease partially corrected, but in no case has there been complete recovery. Methods for improving the results of these operations are ongoing.

Normal. The substantia nigra is intact, and its nerve fibres connect to the striatum

Parkinson’s disease. Most of the neurons in the substantia nigra have died, and few nerve fibres remain to connect to the striatum

A graft of embryonic substantia nigra has been placed in the striatum. It sends out nerve fibres that innervate the striatum and bring back lost neurological function.

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