Parkinson’s disease (PD) is a progressive neurodegenerative disease characterized by the loss of dopaminergic neurons in the brain. These neurons produce dopamine, a chemical that is needed to control movement and other functions. People with Parkinson’s have lower levels of dopamine and, as a result, experience a range of motor symptoms, including tremors, rigidity, bradykinesia (slowness of movement), and postural instability. Additionally, non-motor symptoms such as depression, cognitive impairment, and sleep disturbances can occur. These impact the overall quality of life.
Parkinson’s disease treatment has seen nominal improvements in more than 60 years. Current therapies focus on relieving symptoms but do not slow or stop the progression of the disease. Despite these challenges, we and others have continued to press on in finding ways to help people living with Parkinson’s disease better manage their symptoms and slow or halt disease progression.
Here we summarize a handful of the latest advancements in the field and how cell therapy is ushering in a new era of treatment options.
The current standard of care for PD treatments have focused on symptom management through medications such as dopamine agonists and antagonists, which replenish dopamine levels in the brain, as well as other drugs that mimic or enhance dopamine’s effects. While these treatments provide symptomatic relief, they do not address the underlying cause of neurodegeneration, lose effectiveness over time, and often cause side effects including involuntary, erratic movements known as dyskinesias.
Many of the recent innovations in the PD field have focused on improving externally administered dopamine therapies. For example, patients can now use pumps that supply a constant stream of dopamine. By offering a more consistent delivery, the pumps reduce the duration during which patients experience symptoms such as tremor, rigidity, and dyskinesias. Non-pharmaceutical therapies such as deep brain stimulation and focused ultrasounds are additional available treatment options that have shown benefit in helping patients better manage their motor symptoms. symptoms.
In terms of diagnostic tools, a new assay that has garnered interest is the alpha-synuclein seed amplification test, which detects alpha-synuclein clumps in spinal fluid or skin and can potentially help to diagnose disease at an earlier stage.
The Potential of New Modalities:
While these therapies benefit the surviving neurons, they do not address the underlying loss of dopaminergic neurons. New modalities, including gene therapies and cell therapies, could open the door to additional treatment options.
Gene Therapy
While gene therapies are often associated with treating genetic diseases, such as sickle cell disease and Duchenne muscular dystrophy, they also hold potential for treating other diseases such as Parkinson’s disease.
For example, some researchers are using viral vectors to deliver therapeutic genes into the brain that can promote dopamine production or provide neuroprotective effects to affected neurons, helping to protect them against degradation. Other gene therapies produce enzymes that could potentially enhance how the brain responds to conventional medicines such as levodopa. While the field is still early and there are no FDA-approved gene therapies for Parkinson’s disease, several trials are currently underway, some showing potentially encouraging results.
Cell Therapy
The rise of cell therapy has breathed new life and optimism into treating diseases that were once thought to be out of reach, PD included. New technologies have facilitated the development of bioprocesses that allow pluripotent stem cells to be differentiated into various cell types. Several types of cell therapies are currently in development. Each type of therapy has its strengths and challenges, and ongoing research aims to further refine differentiation techniques to achieve safe, effective, and long-lasting treatments. As with gene therapy, there is not yet an FDA-approved cell therapy for PD; however, multiple clinical trials are similarly underway, with some showing potential patient benefit.
Compared to treatments like dopamine agonists and antagonists, which mainly address symptoms, cell therapy for PD seeks to restore function by replacing lost neurons, generating dopamine in a way that more closely mimics natural physiological processes. Once transplanted, these new neurons could potentially integrate into the brain’s neural network and continue to function over the long term, reducing the need for ongoing medication.
While challenges remain, including ensuring the safety, functionality, and long-term survival of transplanted cells, ongoing research and clinical trials continue to advance the field. With continued progress, new modalities such as cell therapies and gene therapies could potentially offer Parkinson’s patients a chance at not only symptom relief but also a significant improvement in their quality of life and a slowing or even reversal of disease progression.
