A critical review of the current status and possible developments in brain transplantation.

Abstract

Currently much interest is focussed on the possibilities for treatment of neurodegenerative disorders by transplantation of specific transmitter releasing cells to the central nervous system. The term “neurodegenerative” is used to describe disorders characterized by cell loss in the central nervous system and includes Parkinson’s disease, Huntington’s disease, Alzheimer’s disease and amyotrophic lateral sclerosis. They all have in common that their exact etiology and pathogenesis is unknown and that they curtail both the quality and quantity of life. They often slowly progress to a state of severe incapacitation of the sufferer with neurological symptoms related to which specific cell type(s) and neurotransmitter systems are affected. Since no therapy can be offered against the basic etiologies, the treatment, if any, is directed towards symptomatic relief (for comprehensive reviews the reader is referred to Calne 1994). The exciting progress made by biomedical science during the last two decades in understanding the basic mechanisms of growth, behaviour and function of neural transplants in the mammalian central nervous system has opened the possibility for a different and, at least in theory, curative therapeutic strategy aiming at repairing the brain (Dunnett and Bjorklund 1994). The concept may include possibilities for either a partial or even total recovery of function by replacement of lost cell populations to restore specific neurotransmitter systems, neural circuits or to remyelinate fibers in demyelination disorders.