This is not about PD, but pretty impressive and related: Fecal microbiota transplantation associated with 10 years of stability in a patient with SPMS 2018 nn.neurology.org/content/5/...
See chartist 's post on FMT here: healthunlocked.com/cure-par...
I also found a new report on FMT for PD: Fecal microbiota transplant as a potential treatment for Parkinson’s disease – A case series 2021 sci-hub.se/10.1016/j.clineu...