Adult cell therapy for brain neuronal damages and the role of tissue engineering.

No long term effective treatments are currently available for brain neurological disorders such as stroke/cerebral ischemia, traumatic brain injury and neurodegenerative disorders. Cell therapy is a promising strategy, although alternatives to embryonic/foetal cells are required to overcome ethical, tissue availability and graft rejection concerns. Adult cells may be easily isolated from the patient body, therefore permitting autologous grafts to be performed. Here, we describe the use of adult neural stem cells, adrenal chromaffin cells and retinal pigment epithelium cells for brain therapy, with a special emphasis on mesenchymal stromal cells. However, major problems like cell survival, control of differentiation and engraftment remain and may be overcome using a tissue engineering strategy, which provides a 3D support to grafted cells improving their survival. New developments, such as the biomimetic approach which combines the use of scaffolds with extracellular matrix molecules, may improve the control of cell proliferation, survival, migration, differentiation and engraftment in vivo. Therefore, we later discuss scaffold properties required for brain cell therapy as well as new tissue engineering advances that may be implemented in combination with adult cells for brain therapy. Finally, we describe an approach developed in our laboratory to repair/protect lesioned tissues: the pharmacologically active microcarriers.