The overall objective of this pilot study was to obtain additional data on potential protective properties of NAC in PD using an in vitro and in vivo approach. In preparation for the clinical trial, we performed a cell tissue culture study using human embryonic stem cell (hESC)-derived midbrain dopamine neurons (mDA) treated with rotenone as a model for PD.
The primary outcome in the cell tissue cultures was the number of cells that survived the insult with the neurotoxin rotenone. In the clinical trial, patients continued standard treatment and were randomized to receive either daily NAC or to be placed on the waiting list. Patients were assessed before and at 3 months after receiving NAC using DaTscan to measure dopamine transporter (DAT) binding and the Unified Parkinson’s Disease Rating Scale (UPDRS) to measure clinical symptoms.
The results of this preliminary study show for the first time a possible direct effect of NAC on the dopamine system in Parkinson’s disease patients, and this observation may be associated with positive clinical effects. A large-scale clinical trial to test the therapeutic efficacy of NAC in this population and to better elucidate the mechanism of action is warranted.