Effects of pramipexole treatment on the α-synuclein content in serum exosomes of Parkinson's disease patients

Advances approaches in the treatment of Parkinson's disease are needed. The study was aimed to evaluate the therapeutic value of the new dopamine receptor agonist pramipexole. The effects of pramipexole on serum exosomes were investigated, and the possible mechanisms of action of the drug were explored. Initially, 68 patients were included in the study, of whom 3 cases did not complete the study. The remaining 65 patients were administered pramipexole at increasing doses starting at 0.25 mg twice a day for the 1st week, and reaching 1.5 mg three times daily at the 8th week. The doses were tapered during the course of the following 4 weeks. The total scores of the motor examination of the unified Parkinson's disease rating scale III (UPDRS III) and the total scores of the daily life activity in UPDRS II were compared before and after treatment. The relative expression amounts of α-synuclein in serum exosomes were then calculated by western blot analysis. Scores of UPDRS III and UPDRS II following treatment were significantly lower than the scores prior to treatment, and the difference was statistically significant (P<0.05). The relative expression of α-synuclein in serum exosomes was also found to be significantly lower after treatment (P<0.05). The relative expression of α-synuclein in the effective treatment group was significantly lower than that in the ineffective treatment group, and the difference was statistically significant (P<0.05). The relative expression of α-synuclein in serum exosomes was significantly correlated with treatment effects (P<0.05). In conclusion, pramipexole was effective and safe as a treatment for Parkinson's disease. The therapeutic effect of pramipexole may be associated with its reducing effect on the relative expression of α-synuclein in serum exosomes.