Inflammation in Parkinson's disease: an update.

Parkinson's disease (PD) is a degenerative neurological disorder characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) of the brain. The loss of the dopaminergic projection from the SNpc deprives the striatum of dopamine and results in a myriad of motor signs, including tremor, rigidity and ataxia. Although the stimulus for the initiation of the degenerative process is not understood, 80% of the dopaminergic neurons in the SNpc must be lost before the clinical symptoms of the disease are observed. This suggests that the degenerative process is initiated many years before clinical presentation of the disease. The neurodegeneration observed in PD is accompanied by inflammatory processes, and it has been suggested that anti-inflammatory drugs may be useful in slowing disease progression once the clinical signs of PD have been observed. This review summarizes and evaluates the progress that has been made in this area of research since 2006.