Originally Posted by Tupelo3

You have to remember, as TexasTom wrote, that it is misfolded a-syn that is the culprit, not properly folded a-syn which is an essential protein that enables neurotransmitters in the body. Another issue is, which TexasTom didn't get exactly right, is that misfolded a-syn is not an actual prion (e.g. Creutzfeldt-Jakob disease), but rather prion-like. There is a difference as a prion is self-derived, self-sustaining, and infectious. Alpha synuclein, being prion-like, is believed like other neurological misfolded proteins (e.g. amyloid, tau, etc.) to be what is now referred to as a transcellular prionoid. Prionoids are proteins that demonstrate prion-like propagation between cells within a disease context (e;g. Alzheimer's or PD) but have limited evidence for organism infection or transmission.

PubMed Central Image Viewer.

With regard to blood filtering, it would the misfolded prionoid a-syn that you would want to remove, not necessarily all a-syn. This is what the vaccines we have been following target. I'm not aware of any research showing that people on dialysis have a lower instance of Parkinson's. Alternatively, I have seen research that shows that people with end-stage-renal-disease (ESRD) have a significantly higher chance of developing PD. These people would all be on dialysis.