Parkinson's Disease | Stem Cells Australia
Condition
Parkinson’s Disease
Parkinson’s disease (PD) is a condition in the brain that kills off neurons that produce a chemical called ‘dopamine’. Dopamine is an important chemical responsible for communication between neurons within the brain. The cell death happens mostly in the ‘substantia nigra’ which is a main dopamine-producing region in the brain.
Dopamine is important for smooth movements, muscle control, and thinking. Less dopamine in the brain means people affected by PD have symptoms like muscle stiffness, tremors, slowing of movement, balance problems, and sometimes depression or sleep disorders. The drug called Levodopa (L-DOPA) is the most common drug used to treat PD. L-DOPA is converted into dopamine, which helps compensate for the lost dopamine-producing neurons and control some of the patient’s symptoms.
Around 5% of cases of PD are inherited genetically, but what causes it in the other 95% of cases is still unknown.
How could stem cells help?
Although the underlying cause of Parkinson's disease is unknown, scientists do know which cells and areas of the brain are involved, and can use stem cells in the following three ways:
Understanding the disease
Scientists are taking cells from patients with PD, and using these stem cells to produce neurons with the disease in the lab. The diseased neurons act as a powerful tool to study how Parkinson’s disease works.
Developing New Drugs
By making cells from patients with Parkinson’s disease, and using these stem cells to produce diseased neurons in the lab, scientists can screen for substances that could be developed into new drugs to treat the disease.
Replacing Lost Cells
Stem cell research also potentially offers a way to provide replacement ‘healthy’ dopamine producing neurons to replenish those lost to the disease. Although new cell treatments from stem cells are still not approved for PD patients, results from previous clinical trials involving the transplantation of young brain cells from human fetuses into people with PD has shown promising results.
Scientists can now make dopamine-producing neurons from human stem cells. Neurons made from human stem cells mature into human dopamine-producing neurons, survive and function after transplanting them into rats, mice, and monkeys. More research is required to determine whether such an approach could work in people with PD.
What are the challenges?
Scientists are still trying to understand the genetics behind PD. At present only 5% of PD cases are linked to genetics. This makes it very difficult to understand the exact causes of PD.
Although the medications we have for PD are very useful, they begin to lose effectiveness after several years. Stem cell treatments potentially offer a way to provide new neurons that can replace the neurons lost to the disease.
Stem cell treatments in humans are still not approved for the treatment of PD. Studies done in animals have shown that human dopamine neurons from human stem cells are safe and appear to function like the neurons in the substantia nigra. However, it still needs to be shown from clinical trial research that this kind of treatment is effective and beneficial to people with PD. Further evidence is required before cell therapies are routinely available for PD patients.
Where can I find out more about clinical trials?
There are a number of sites that list clinical trials, including the clinicaltrials.gov registry. Please note that the scientific justification for the intervention and the credentials of those offering the service may have NOT been fully evaluated by this registry and may not be a legitimate trial.
Please consult with your medical specialist or general practitioner as they are best placed to advise you on whether you would be a good candidate for a trial given your circumstances.
Please note: Although some clinics may claim to already offer stem cell treatments for PD, there are serious questions about the scientific rationale and the safety of many of these approaches. Currently, there are no proven, safe and effective stem cell treatment for this disease available in Australia, the EU, US or elsewhere.
Some of this material has been adapted from factsheets produced by EuroStemCell.org under a Creative Commons license.
Where else can I go to find out more?
Parkinson's Disease & Stem Cells Fact Sheet
International Society for Stem Cell Research