Advanced therapies, including cell and gene therapies, are in development for Parkinson's disease. In many cases, the goal is to replace the lost dopamine, which is anticipated to improve motor dysfunctions associated with dopamine loss. This publication casts some doubts on this strategy.
For Mariah J Lelos from Cardiff University, it is not clear the extent to which these therapeutic interventions may impact on the wide range of cognitive symptoms that manifest as the disease progresses.
Although the accepted perception is that cognitive symptoms are predominately non-dopaminergic in origin, in this commentary, Lelos argues that several, specific cognitive processes, such as habit formation, working memory and reward processing, have been reported to be dopamine-dependent.
Furthermore, there is evidence of dopaminergic medications modulating these behaviors in Parkinson disease patients. Finally, the potential for cell and gene advanced therapies to influence these symptoms is considered.
Lelos concludes that dopamine replacement through advanced therapies is likely to improve certain dopamine-dependent symptoms, but only sparse clinical data are currently available and the ability to precisely titrate dopamine transmission is likely to be complex.