Cell therapy is a promising strategy for tissue repair in the central nervous system. In this perspective, several cell types are being considered, including allogenic neuroblasts, embryonic stem cells and induced pluripotent stem cells. The use of allogenic neuroblasts as cell source is limited by logistics and ethical problems whereas transplantation of the last two cell types is hampered by their propensity to generate tumour. In this context, transplantation of xenogeneic neural cells appears as an attractive approach for effective neuronal replacement in case of neurodegenerative disorders.
With the emergence of embryonic and induced pluripotent stem cells as potential cell source in regenerative medicine, little attention has been paid to the possibility of transplanting xenogenic neural cells in the central nervous system. However, recent progress to circumvent the host immune response in the brain has raised encouraging perspectives for intracerebral xenotransplantation as restorative strategy.
To date, most of the immunosuppressive strategies designed for long-term survival of intracerebral neural transplants were based on systemic immunosuppression that has detrimental side-effects. The immunological status of the brain and the presence of the blood–brain barrier raise the possibility of local immunosuppression. This article provides an overview of the strategies recently developed to protect intracerebral neural transplants with special focus on local immunosuppression.
aINSERM, UMR643, France
bCHU de Nantes, Institut de Transplantation-Urologie-Néphrologie, ITUN, France
cUniversité de Nantes, Faculté de Médecine, Nantes, France
dDirezione Sanitaria, Padua General Hospital, Italy
eCORIT (Consorzio per la Ricerca sul Trapianto d'Organi), Padua, Italy
Correspondence to Dr Isabelle Neveu, INSERM UMR643, CHU Hôtel Dieu, 30 Bd Jean Monnet, 44 093 Nantes cedex 01, France Tel: +33 240 087 414; fax: +33 240 087 411; e-mail: Isabelle.Neveu@univ-nantes.fr