Brain repair for Parkinson's disease: is the answer in the matrix?

Abstract

Two hundred years after James Parkinson first described the cardinal motor symptoms of the disorder that would later bear his name, there is still an irrefutable need for a therapy that targets the underlying pathophysiology of the disease and not solely its symptoms. Parkinson’s disease (PD) is classically characterised by Lewy body formation and a relatively selective degeneration of nigrostriatal dopaminergic neurons (Schapira and Jenner, 2011). The loss of dopaminergic neurons from the substantia nigra pars compacta causes a consequential depletion of the neurotransmitter dopamine from the striatum, and it is this loss that causes the motor symptoms experienced by patients. To date, all treatments for this condition are symptomatic in that they simply endeavour to correct the neurochemical and/or electrical anomalies caused by striatal dopaminergic deafferentation in an attempt to improve motor function (LeWitt and Fahn, 2016). While such symptomatic approaches show extraordinary efficacy in the early years after initiating treatment, the underlying disease pathology continues to progress, and eventually their efficacy subsides. In view of this, there remains an urgent need for an alternative treatment approach that is capable of protecting or repairing the brain in order to provide a more sustained benefit to patients.