Tissue engineering for reconstructing the central dopaminergic nigro-striatal pathway in Parkinson’s disease: Cutting edge cell culture studies

Although neurotransplantation of primary fetal cells into the striatum of patients with Parkinson’s disease (PD) has been reported to be effective, poor clinical outcome and severe side effects lower clinical long-term results. A major drawback of cell replacement therapies in PD is the low cell survival and lacking regeneration of the neuronal circuitries due to the ectopic transplantation of cells into the host striatum. More anatomic and functional integration could potentially be reached by an orthotopic cell transplantation into their natural position within the rostral mesencephalon at the site of the Substantia nigra, where dopaminergic cells get lost in PD. The aim of the thesis was to provide the scientific basis for the use of injectable bioscaffols containing chemo-attractants promoting cell survival, differentiation and axo-dendritic outgrowth of dopaminergic cells. With the so called “bridging” transplantation technology an artificial axon pathway between the substantia nigra and the striatum with targeted nigro-striatal re-innervation should be generated. Thereby, the central dopaminergic nigro-striatal pathway would be reconstructed enabling a fully integration of grafted neurons into the basal ganglia circuitries. The main focus of the thesis was to explore the influence of bioscaffolds on cell survival and morphology of dopaminergic neurons in vitro. The investigations included isolation of primary fetal mesencephalic cells and fetal mesencephalic neural stem cells (NSCs) from embryonic (E14) mouse brain and their culture on ECM compounds and starPEG-heparin hydrogels. Initial characterizations of the gels showed separate as well as simultaneous immobilization and release of growth factors demonstrating that hydrogels could serve as an efficient storage and delivery system for growth factors. The axo-dendritic outgrowth of dopaminergic cells including primary branching, total branching and neurite elongation; cell survival studies; cell type analysis and cell migration were analyzed by ...