INTRASTRIATAL TRANSPLANTATION OF RAT ADRENAL CHROMAFFIN CELLS SEEDED ON MICROCARRIER BEADS PROMOTE LONG-TERM FUNCTIONAL RECOVERY IN HEMIPARKINSONIAN RATS

Possible biologic treatments for Parkinson's disease, a disorder cause d by the deterioration of dopaminergic neurons bridging the nigrostria tal system, have recently focused on fetal cell transplantation. Becau se of ethical and tissue availability issues concerning fetal cell tra nsplantation, alternative cell sources are being developed. The adrena l medulla has been used as a cell transplant source because of the cap acity of the cells to provide catecholamines and to transform into a n euronal phenotype. However, adrenal tissue transplants have shown limi ted success, primarily because of their lack of long-term viability. R ecently, seeding adrenal chromaffin cells on microcarrier beads has be en shown to enhance the cell viability following neural transplantatio n. In the present study, we further investigated whether transplantati on of rat adrenal chromaffin cells seeded on microcarrier beads into t he striatum of 6-hydroxydopamine-induced hemimpar-kinsonian rats would result in a sustained functional recovery. Behavioral tests using the apomorphine-induced rotational and elevated body swing tests up to 12 months posttransplantation revealed a significant behavioral recovery in animals that received adrenal chromaffin cells seeded on microcarr ier beads compared to animals that received adrenal chromaffin cells a lone, medium alone, or beads alone. Histological examination of tissue at 14 months posttransplantation revealed evidence of tyrosine hydrox ylase-positive cells and an on-going glial response in animals transpl anted with adrenal chromaffin cells seeded on microcarrier beads, in c ontrast to absence of such immunoreactive responses in the other group s. These findings support a facilitator role for microcarrier beads in transplantation of adrenal chromaffin cells or other cells that are e asily rejected by the CNS. (C) 1998 Academic Press.