Parkinson's patients show positive response to implants

Dynamic behavior of cells within neurospheres in expanding populations of neural precursors

Large-scale expansion of neural stem and progenitor cells will be essential for clinically treating the large number of patients suffering from neurodegenerative disorders such as Parkinson's disease. Other applications of neural stem cell technology include further research in areas such as neural development or drug testing. Neural stem cells can be grown in vitro as tissue aggregates known as neurospheres, and in the current study, experiments were performed to determine the spatial arrangement and behavior of the cells within the neurosphere structure. A protocol utilizing sulfonated lipophilic fluorescent dyes was developed to effectively label populations of neural stem and progenitor cells without compromising cell density during culture. Cells retained the labels for at least 7 days. Using the labeling protocol, we discovered that the cells within the neurospheres were mobile and, moreover, the cells on the periphery of the neurospheres could migrate into the center of the neurospheres. Most important, the mixing time of two merging neurospheres was observed to be the same order of magnitude as the neural stem cell doubling time (approximately 20 h). This study is the first to show that the neurosphere system is dynamic, and these results will serve as a stepping stone to more in-depth studies of the neurosphere microenvironment.

Large-scale expansion of mammalian neural stem cells: a review

A relatively new approach to the treatment of neurodegenerative diseases is the direct use of neural stem cells (NSCs) as therapeutic agents. The expected demand for treatment from the millions of afflicted individuals, coupled with the expected demand from biotechnology companies creating therapies, has fuelled the need to develop large-scale culture methods for these cells. The rapid pace of discovery in this area has been assisted through the use of animal model systems, enabling many experiments to be performed quickly and effectively. This review focuses on recent developments in expanding human and murine NSCs on a large scale, including the development of new serum-free media and bioreactor protocols. In particular, engineering studies that characterise important scale-up parameters are examined, including studies examining the effects of long-term culture of NSCs in suspension bioreactors. In addition, recent advances in the human NSC system are reviewed, including techniques for the evaluation of NSC characteristics.

Toward full restoration of synaptic and terminal function of the dopaminergic system in Parkinson's disease by stem cells

New therapeutic nonpharmacological methodology in Parkinson's disease (PD) involves cell and synaptic renewal or replacement to restore function of neuronal systems, including the dopaminergic (DA) system. Using fetal DA cell therapy in PD patients and laboratory models, it has been demonstrated that functional motor deficits associated with parkinsonism can be reduced. Similar results have been observed in animal models with stem cell-derived DA neurons. Evidence obtained from transplanted PD patients further shows that the underlying disease process does not destroy transplanted fetal DA cells, although degeneration of the host nigrostriatal system continues. The optimal DA cell regeneration system would reconstitute a normal neuronal network capable of restoring feedback-controlled release of DA in the nigrostriatal system. The success of cell therapy for PD is limited by access to preparation and development of highly specialized dopaminergic neurons found in the A9 and A10 region of the substantia nigra pars compacta as well as the technical and surgical steps associated with the transplantation procedure. Recent laboratory work has focused on using stem cells as a starting point for deriving the optimal DA cells to restore the nigrostriatal system. Ultimately, understanding the cell biological principles necessary for generating functional DA neurons can provide many new avenues for better treatment of patients with PD.