Transplantation of central nervous tissue

The inability of the central nervous system (CNS) to regenerate after injury has long been known. However, extensive research into regeneration during the past 2 decades has demonstrated a degree of CNS plasticity that was heretofore thought impossible. Subsequently, research into CNS transplantation has documented the ability of transplanted CNS tissues to survive, develop processes, elongate, organize into anatomically correct configurations, and establish electrophysiologically and secretorly functional synaptic connections with the host tissue. This review focuses on current trends and techniques in CNS transplantation, with special emphasis on target tissue transplantation, peripheral nerve-axonal bridge transplantation, and neuronal replacement by transplantation. Although the majority of CNS transplantation research remains in the domain of the neurobiologists, a substantial amount is beginning to reach the level of practical clinical application. The capability of transplanting neurons to correct CNS abnormalities, whether due to disease, trauma, or genetic defects, has enormous neurosurgical implications.