LONG-TERM VIABILITY OF ISOLATED BOVINE ADRENAL-MEDULLARY CHROMAFFIN CELLS FOLLOWING INTRASTRIATAL TRANSPLANTATION

Adrenal medullary grafts generally exhibit poor viability when grafted into the striatum. Previous work in our laboratory demonstrated that chromaffin cells can survive well for up to 2 mo following grafting in to the intact rat striatum after cells are isolated from the nonchroma ffin supporting cell (fibroblasts and endothelial cells) of the adrena l medulla. The aim of the present study was to assess the long-term vi ability of isolated bovine chromaffin cells following grafting into th e intact rat striatum. The viability of grafted bovine adrenal medulla ry chromaffin cells was compared in rats receiving either (a) perfused adrenal medulla; (b) isolated chromaffin cells; or (c) isolated chrom affin cells that were subsequently recombined with their nonchromaffin supporting cells. One year postimplantation, all graft types which in cluded fibroblasts and endothelial cells were infiltrated with macroph ages and demonstrated an abundance of cellular debris. No viable chrom affin cells were observed. In contrast, healthy tyrosine hydroxylase ( TH) and dopamine beta hydroxylase (D beta H) immunoreactive chromaffin cells survived for 1 yr posttransplantation when grafted in isolation from the nonchromaffin constitutents of the adrenal medulla. Good Xen ograft survival was achieved in this group despite the fact that these rats were only immunosuppressed for 1 mo postimplantation. Grafted ce lls demonstrated morphological characteristics of chromaffin cells in situ and these implants were not accompanied by macrophage infiltratio n. These data demonstrate that long-term survival of chromaffin cells can be achieved following intrastriatal implantation an the viability of grafted chromaffin cells is dependent upon the removal of the nonch romaffin supporting cells.