Neural stem cells and the aging brain : part 2

Abstract

Neural stem cells have a number of potential applications in treating neurodegenerative disorders. Neurons lost duri~g the disease process may be replaced either by facilitating the proliferation of neural stem cells already present in the brain (endogenous replacement) or else by transplantation of neural stem cells in the damaged area of the brain (exogenous replacement). For transplantation to be viable, cells have to fulfill three important criteria. Firstly, the transplanted cells must survive the procedure. Secondly, the transplanted neural stem cell has to develop in the required type of brain cell and finally, the transplanted cell must make the necessary connections to survive and be part of the existent neural network. If transplantation occurs in a diseased brain, the newly transplanted cell must also survive in the dis eased environment. Although recent studies using animal models showed promising results, exogenous transplantation of neural stem cells is still a long way to go. One of the major limitations is that it is still difficult to produce the type of replacement cell needed following differentiation in vivo.