Regenerative Therapies for Parkinson's Disease: An Update.

Parkinson's disease is the second most common neurodegenerative disorder. It is characterised by a typical movement disorder that occurs in part because of the selective degeneration of the dopaminergic neurons of the substantia nigra pars compacta. Current treatment for the motor disorder of Parkinson's disease consists of dopaminergic medications, but these come with significant adverse effects, themselves an important part of the clinical course of Parkinson's disease, particularly in advanced stages. Therefore, treatment is needed that can restore dopaminergic tone in the striatum in a physiological and targeted manner to avert these side effects. A number of potential regenerative treatments have been developed with a view to achieving this. Following decades of optimisation and development of stem-cell-based treatments and viral gene delivery, clinical trials are on the horizon. For these treatments to be widely useful, they must be clinically effective, cost efficient and safe, and a number of practical aspects regarding storage and delivery of treatment must be optimised. Many barriers have been overcome, and the field of regenerative medicine for Parkinson's disease is now increasingly focussed on how these treatments will be delivered, demonstrating the significant progress that has been made and the optimism surrounding these approaches.