No abstract

The present study investigated the neuroanatomical and behavioral effects of human stem cell transplants into the striatum of quinolinic acid (QA)-lesioned rats. Twenty-four rats received unilateral QA (200 nM/microl) injections into the striatum. One week later, rats were transplanted with stem cells derived from human fetal cortex (12 weeks postconception) that were either 1) pretreated in culture media with the differentiating cytokine ciliary neurotrophic factor (CNTF; n = 9) or 2) allowed to grow in culture media alone (n=7). Each rat was injected with a total of 200,000 cells. A third group of rats (n=8) was given a sham injection of vehicle. Rats transplanted with human stem cells performed significantly better over the 8 weeks of testing on the cylinder test compared with those treated with vehicle (P < or = 0.001). Stereological striatal volume analyses performed on Nissl-stained sections revealed that rats transplanted with CNTF-treated neurospheres had a 22% greater striatal volume on the lesioned side compared with those receiving transplants of untreated neurospheres (P = 0.0003) and a 26% greater striatal volume compared with rats injected with vehicle (P < or = 0.0001). Numerous human nuclei-positive cells were visualized in the striatum in both transplantation groups. Grafted cells were also observed in the globus pallidus, entopeduncular nucleus, and substantia nigra pars reticulata, areas of the basal ganglia receiving striatal projections. Some of the human nuclei-positive cells coexpressed glial fibrillary acidic protein and NeuN, suggesting that they had differentiated into neurons and astrocytes. Taken together, these data demonstrate that striatal transplants of human fetal stem cells elicit behavioral and anatomical recovery in a rodent model of Huntington's disease.

Glial cell line-derived neurotrophic factor (GDNF) has been shown to increase the survival and functioning of dopamine neurons in a variety of animal models and some recent human trials. However, delivery of any protein to the brain remains a challenge due to the blood/brain barrier. Here we show that human neural progenitor cells (hNPC) can be genetically modified to release glycosylated GDNF in vitro under an inducible promoter system. hNPC-GDNF were transplanted into the striatum of rats 10 days following a partial lesion of the dopamine system. At 2 weeks following transplantation, the cells had migrated within the striatum and were releasing physiologically relevant levels of GDNF. This was sufficient to increase host dopamine neuron survival and fiber outgrowth. At 5 weeks following grafting there was a strong trend towards functional improvement in transplanted animals and at 8 weeks the cells had migrated to fill most of the striatum and continued to release GDNF with transport to the substantia nigra. These cells could also survive and release GDNF 3 months following transplantation into the aged monkey brain. No tumors were found in any animal. hNPC can be genetically modified, and thereby represent a safe and powerful option for delivering growth factors to specific targets within the central nervous system for diseases such as Parkinson's.

No abstract

The use of human neural progenitor cells (hNPC) has been proposed to provide neuronal replacement or astrocytes delivering growth factors for brain disorders such as Parkinson's and Huntington's disease. Success in such studies likely requires migration from the site of transplantation and integration into host tissue in the face of ongoing damage. In the current study, hNPC modified to release glial cell line derived neurotrophic factor (hNPC GDNF ) were transplanted into either intact or lesioned animals. GDNF release itself had no effect on the survival, migration or differentiation of the cells. The most robust migration and survival was found using a direct lesion of striatum (Huntington's model) with indirect lesions of the dopamine system (Parkinson's model) or intact animals showing successively less migration and survival. No lesion affected differentiation patterns. We conclude that the type of brain injury dictates migration and integration of hNPC which has important consequences when considering transplantation of these cells as a therapy for neurodegenerative diseases.