Cellular xenotransplantation.
OBJECTIVE
Expectations are high on cellular therapy. Being fundamental to elucidate organogenesis, it is unlikely that embryonic stem cells will be used for clinical purposes. Postembryonic stage, developing cells are, therefore, the front-runner for regenerative medicine. In addition to autologous cells, both allogeneic and xenogeneic cells are hypothetical candidates to treat specific diseases. This review summarizes the current knowledge on immunological and functional aspects of xeno(allo)-cellular transplantation for cardiomyopathy, diabetes, liver failure, neural diseases, and bone regeneration.


RESULTS
Xenocellular transplantation is promising for tissue repair in immunologically privileged sites such as the central nervous system or nonvascularized tissues in which no or moderate immunosuppression is required. In vascularized organs, major immune responses are present when cells are transplanted without additional conditioning. Positive results from encapsulation methods that protect cells from the immune system should further stimulate preclinical research. Also, conditioning immunosuppression could be used to circumvent the initial immune response. Transgenic pigs cells are probably the best xenogeneic substitute for human application, although basic research on innate and noninnate immunity toward pig cells is still required.


CONCLUSIONS
In several fields of medicine, cellular xenotransplantation is slowly emerging as a potential therapeutic tool.
Poncelet
Alain J
AJ
Laboratory of Experimental Surgery, Faculté de Médecine, Cliniques Universitaires Saint-Luc, Université catholique de Louvain, Brussels, Belgium.
Denis
Dufrane
D
Gianello
Pierre
P
D000818:Animals; D001847:Bone Diseases / Q000601:surgery; D002470:Cell Survival; D003922:Diabetes Mellitus, Type 1 / Q000601:surgery; D006085:Graft Survival; D006333:Heart Failure / Q000601:surgery; D022781:Hepatocytes / Q000276:immunology / Q000637:transplantation*; D006801:Humans; D006816:Huntington Disease / Q000601:surgery; D016381:Islets of Langerhans Transplantation; D017093:Liver Failure / Q000601:surgery; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000276:immunology; D009474:Neurons / Q000276:immunology / Q000637:transplantation*; D010300:Parkinson Disease / Q000601:surgery; D044968:Regenerative Medicine; D013552:Swine; D019172:Transplantation Conditioning; D023001:Transplantation Tolerance; D014183:Transplantation, Heterologous; D014184:Transplantation, Homologous