The Journal of Neuroscience, August 1, 1998, 18(15):6040-6047
Optimal Effectiveness of BDNF for Fetal Nigral Transplants
Coincides with the Ontogenic Appearance of BDNF in the Striatum
David M.
Yurek1,
Susan
B.
Hipkens1,
Stanley J.
Wiegand2, and
C. Anthony
Altar2
1 Department of Surgery/Neurosurgery and Anatomy and
Neurobiology, University of Kentucky College of Medicine, Lexington,
Kentucky 40536, and 2 Regeneron Pharmaceuticals, Inc.,
Tarrytown, New York 10591
Transplantation of fetal nigral dopamine neurons into the caudate
and putamen of Parkinson's disease patients produces limited symptomatic relief. One approach to augment the outgrowth and function
of nigral grafts includes exposure of the graphs to neurotrophic factors; however, the temporal requirements for optimizing these actions are unknown. The present study characterized the ontogeny of
brain-derived neurotrophic factor (BDNF) in the rat striatum and used
this information to define and evaluate three distinct periods of BDNF
infusion into fetal nigral grafts transplanted into the striatum of
rats with experimental Parkinson's disease. At postnatal day 1 (P1), BDNF and dopamine were measured at 17 and 27% of peak
levels, respectively, that occurred at P27 for both. Both compounds
showed their greatest surge between P7 and P20, increasing from 40% to
~95% of peak levels. Exogenous BDNF infused into transplants during
weeks 1 and 2 after the transplantation, which coincide with the
developmental period embryonic day 14 (E14)-P7 for transplanted
tissue, did not improve rotational behavior or enhance fiber outgrowth
of transplanted dopamine neurons. Delaying the BDNF infusion until
transplanted tissue was approximately P8-P21 greatly enhanced the
effect on rotational behavior and doubled the area of dopamine fiber
outgrowth from the transplants. Delaying the infusion until
transplanted tissue was approximately P36-P49 failed to augment fiber
outgrowth and decreased the behavioral function of transplants. Thus,
the optimal effect of exogenous BDNF on the development of dopamine
neurons in fetal nigral transplants occurs at a postnatal age when
endogenous dopamine and BDNF show the greatest increases during the
normal development of the striatum.
Key words:
brain-derived neurotrophic factor; development; dopamine; Parkinson's disease; neural transplantation; neurotrophic factor; fiber outgrowth
Copyright © 1998 Society for Neuroscience 0270-6474/98/18156040-08$05.00/0