Potential cellular and regenerative approaches for the treatment of Parkinson's disease

The early stages of Parkinson’s disease is normally treated with pharmacotherapeutics, but their ability to control both motor and non-motor symptoms is reduced in advanced stages of the disease. The recent development of new surgical techniques, such as deep brain stimulation, has added to the neurologists armamentarium, but new therapeutic strategies are still required. Viral vectors and stem cells are an increasingly viable alternative. Providing a continuous supply of dopamine in the striatum by using enzymes involved in dopamine synthesis is one option. Alternatively, there are tools that may be both neuroprotective and serve to encourage growth of surviving neurons using either growth factors or by directly replacing lost innervation through the transplantation of primary tissue or stem-cell derived domapinergic neurons. This review summarizes these potential therapeutic approaches and considers the recent EU directives on practical aspects of handling viral vectors, cells and tissues, and in the running of clinical trials in Europe which impact on their development.