LONG-TERM SURVIVAL OF TRANSPLANTED BASAL FOREBRAIN CELLS FOLLOWING IN-VITRO PROPAGATION WITH FIBROBLAST GROWTH FACTOR-II

The intracerebral transplantation of freshly dissected fetal tissue co ntaining cholinergic neurons of the developing basal forebrain has bee n reported to reverse lesion-induced or age-related cognitive deficits in animal models of cholinergic neuronal degeneration. Grafts of cult ured fetal neurons, however, have generally shown poor cellular surviv al and limited therapeutic benefit. We tested the hypothesis that rece nt advances in the identification of growth factors that promote the s urvival and propagation of fetal precursor cells in vitro would improv e the long-term survival of cultured neurons following intracerebral i mplantation. Dissociated cells from gestational Day 14 rodent basal fo rebrain were grown in chemically defined media supplemented with 28 ng /ml basic fibroblast growth factor. Two weeks postplating, numerous ce lls were present in the cultures and showed iunmunoreactive labeling f or a variety of markers, including glutamic acid decarboxylase, neuron -specific enolase, neurofilament proteins, glial fibrillary acidic pro tein. and, occasionally, choline. acetyltransferase. To determine if c ultured basal forebrain cells would survive intracerebral implantation , the cells were implanted homotypically into the nucleus basalis magn ocellularis. To enhance the potential for graft survival in vivo, cell s were also implanted into the nucleus basalis magnocellularis followi ng an ibotenic acid lesion and into the denervated frontal cortex. Ani mals sacrificed between 2 weeks and 7 months following transplantation showed good and comparable graft survival in all sites. Immunocytoche mical analysis revealed that representative populations of cells obser ved in vitro survived for prolonged periods in vivo even in sites dist al from their normal cellular targets. Thus, neuronal populations expa nded in vitro can successfully survive and maintain cellular phenotype s post-transplantation. These results suggest a potential for isolatin g and growing specific neuronal populations in vitro for intracerebral transplantation. (C) 1996 Academic Press, Inc.