Fetal transplantation for the treatment of neurodegenerative diseases - Current status and future potential

Patients with neurodegenerative diseases currently have few treatment options. However, neurotransplantation represents one potential treatment avenue. Animal studies using lesion-induced models of neurodegenerative disorders such as Parkinson's disease, Huntington's disease and Alzheimer's disease have shown that transplantation of appropriate fetal tissue can improve motor and cognitive deficits. Clinical trials of transplantation for Parkinson's disease and, recently, Huntington's disease have demonstrated limited success in controlling symptoms, with some patients exhibiting greater improvement than others. Among the many factors that may influence the clinical success of transplantation, graft volume has recently been shown to correlate with motor improvement. Additional factors such as the age of the transplanted tissue or the disease stage of the host must also be investigated. Other potential means of improving the symptoms of neurodegenerative diseases include gene transfer or administration of neurotrophic factors, either through direct infusion or by transplantation of biological sources. Currently, however, these treatment strategies are still under development and have not been assessed clinically. Continued refinement of the technique of neurotransplantation, possibly in combination with these alternative approaches, promises steady improvement in the treatment options for patients with neurodegenerative disease.