Journal of Neuroscience, Vol 13, 4496-4510, Copyright © 1993 by Society for Neuroscience
Robust survival of isolated bovine adrenal chromaffin cells following intrastriatal transplantation: a novel hypothesis of adrenal graft viability
SB Schueler, JD Ortega, J Sagen and JH Kordower
Department of Anatomy and Cell Biology, University of Illinois School of Medicine, Chicago.
Previous investigations have demonstrated that adrenal chromaffin cells
survive poorly when grafted into the striatum of rodents, nonhuman
primates, and patients with Parkinson's disease. This poor survival has
been attributed to the low levels of endogenous NGF within the striatum.
However, chromaffin cells isolated from the nonchromaffin constituents of
the adrenal medulla (fibroblasts and endothelial cells) have recently been
demonstrated to survive grafting into a number of CNS sites. The present
study determined whether nonchromaffin constituents of the adrenal medulla
may be responsible for poor graft survival. We compared the survival of
intrastriatally grafted isolated bovine chromaffin cells with that observed
following implantation of either perfused adrenal medullary suspensions
containing all adrenal medullary cell types or isolated chromaffin cells
that were then reseeded with autologous fibroblasts and endothelial cells.
Implants of perfused adrenal medullary cells survived poorly and most graft
sites were infiltrated with macrophages. The chromaffin cells in this group
that did survive appeared to be in the process of degeneration. In
contrast, large numbers of isolated chromaffin cells survived for up to 2
months following transplantation. These cells maintained their endocrine
phenotype and stained for all enzymatic markers of catecholamine synthesis
as well as chromogranin A. Morphologically, these cells resembled
chromaffin cells seen in situ and the perigraft region was essentially
devoid of macrophages. When isolated chromaffin cells were reseeded with
autologous fibroblasts and endothelial cells, the implants degenerated and
few, if any, surviving chromaffin cells were observed. Interestingly, these
latter grafts induced a host- derived sprouting response of tyrosine
hydroxylase-immunoreactive fibers. These data demonstrate that large
numbers of adrenal chromaffin cells can survive intrastriatal implantation
in the absence of exposure to exogenous NGF. Rather, the nonchromaffin
cells of the adrenal medulla (fibroblasts and endothelial cells) appear to
compromise the viability of grafted chromaffin cells. Once they are
eliminated from the graft, robust survival of chromaffin cells occurs. If
clinical trials employing adrenal medullary grafts are still to be
considered for the treatment of Parkinson's disease, isolation of the
chromaffin cells should be considered to enhance graft viability.