This first paper proposes a link between inflammation and BBB damage, leading to degeneration of dopamine neurons.

http://www.ncbi.nlm.nih.gov/pubmed/20423606
"Additionally, several groups have proposed that dysfunction of the blood-brain barrier (BBB) combined with infiltration of peripheral immune cells play important roles in the degeneration of DA neurons. "

http://boquetespa.com/2010/05/alzhei...%99t-remember/
"Between our brain and the rest of our body is the blood brain barrier (BBB) it is there to protect the brain from whatever is circulating around in our blood. If the body is in a state of chronic inflammation, it eventually compromises our blood brain barrier" ......research has revealed a relationship between inflammation and oxidative stress causing brain cell damage or death, leading to dementia and many other problems like Alzheimer’s disease and even Parkinson’s disease.

Ron