Stem Cells in Neurodegeneration

The neural stem cell niche in the adult brain is a complex environment formed by several types of cells, a particular type of extracellular matrix and specific molecular cues. Ageing is characterized by reduced neurogenesis, due to altered neurotrophin signaling, activation of senescence programmes within the niche, imbalanced growth factor signalling. A recent concept is that blood-born ageing factors signal or cross the blood brain barrier to negatively influence the neurogenesis. Neurodegenerative diseases are an appealing target for regenerative medicine and stem cell transplant was held for quite some time in high consideration and brought about high hopes for the replacement of lost cells and tissue function restoration. One of the major drawbacks is that most transplanted cells differentiate on glial line; therefore, new strategies were implemented. From transplantation of committed neuronal progenitors, to neurosphere transplant or autologous mesenchymal stem cells, these strategies are presented and some of the drawbacks highlighted in the present chapter.

Keywords: Alzheimer’s disease, Hippocampus, Neural precursors, Neurodegeneration, Parkinson’s disease, Stem cells, Subventricular zone.