A comparison of dopaminergic cells from the human NTera2/D1 cell line transplanted into the hemiparkinsonian rat

Human NT cells derived from the NTera2/D1 cell line express a dopaminergic phenotype making them an attractive vehicle to supply dopamine to the depleted striatum of the Parkinsonian patient. In vitro, hNT neurons express tyrosine hydroxylase (TH), depending on the length of time they are exposed to retinoic acid. This study compared two populations of hNT neurons that exhibit a high yield of TH+ cells, MI-hNT and DA-hNT. The MI-hNT and DA-hNT neurons were intrastriatally transplanted into the 6-OHDA hemiparkinsonian rat. Amelioration in rotational behavior was measured and immunohistochemistry was performed to identify surviving hNT and TH+ hNT neurons. Results indicated that both MI-hNT and DA-hNT neurons can survive in the striatum, however, neither maintained their dopaminergic phenotype in vivo. Other strategies used in conjunction with hNT cell replacement are likely needed to enhance and maintain the dopamine expression in the grafted cells.