Stem cell therapy for Parkinson’s: Are we getting closer?
Stem cells hold promise for slowing, or even reversing, the progression of Parkinson’s. For more than a decade, researchers have worked to harness the potential of stem cells to treat Parkinson’s. In this blog, we will take a look at the research, see how far we’ve come and look to the future.
Around 153,000 people live with Parkinson’s in the UK. Whilst the underlying cause of Parkinson’s is unknown, it is widely understood that Parkinson’s results from a lack of dopamine in the brain. Dopamine is a chemical that is produced by cells in an area of the brain called the substantia nigra. It plays an important role in carrying messages between brain cells.
In people with Parkinson’s, the cells in the brain that produce dopamine become damaged, stop working, and are lost over time. This means that there’s not enough dopamine, which can lead to the development of Parkinson’s symptoms.
The brain doesn’t have a way of replacing or even repairing these damaged dopamine cells. So once they’re gone, they’re gone. But what if there was a treatment that could help replace these damaged cells with new healthy cells?
What are stem cells?
Stem cells can develop into many different types of cells. Every cell in your body will have started life as a stem cell.
This ability makes stem cells particularly exciting for researchers. In theory, if we can turn stem cells into any cell in the human body, they could potentially be used to replace damaged or lost cells seen in several medical conditions. Early stage research is currently exploring whether stem cells may one day be beneficial for diabetes, spinal cord injuries and Parkinson’s among others.
Stem cells also help researchers to understand more about different conditions. In Parkinson’s research, we can study dopamine-producing brain cells that have been derived from stem cells. This may uncover answers as to why these cells stop producing dopamine in people with Parkinson’s.
How are stem cells used in research?
There are several different types of stem cells. Many of these have been explored by researchers hoping to find an effective stem cell therapy for Parkinson’s.
Adult stem cells
Adult stem cells were first discovered in the 1960s. They can be found all over the body, including in our brains, and help regenerate old and damaged tissues and cells. However, they can only develop into a limited number of cell types.
For example, a stem cell from the liver only has the instructions to become a new liver cell. In the brain, there are no stem cells that can prevent or repair damage caused by Parkinson’s. Adult stem cells are therefore the least commonly used in Parkinson’s research.
Embryonic stem cells
Embryonic stem cells were discovered in the early 1980s and are found inside developing embryos. They can develop into any type of cell in the human body. Because these cells come from human embryos, there are ethical questions to consider and strict legal guidelines for using embryonic cells for research.
Induced pluripotent stem (iPS) cells
These stem cells are made by scientists in a laboratory. They are created by reverting normal body cells, such as skin cells, back into stem cells. These stem cells can then become any cell in the human body.
This means that it may now be possible to take cells from a person with Parkinson’s, such as skin cells, and turn them into brain cells that can produce dopamine. This should mean that the transplanted cells are less likely to be rejected and cause side effects, because the person would be treated with their own cells.
Using stem cells in medicine has been of interest to scientists for over 50 years. So far, it has taken a global effort of hundreds of researchers to study stem cells in the lab, understand their potential, and consider how they may one day treat medical conditions such as Parkinson’s.
What does the research say?
To understand if stem cell therapy is safe and effective for people with Parkinson’s, large-scale clinical trials must be carried out. Participants have to be monitored for a long time after receiving the treatment, meaning clinical trials can span many years.
Whilst there is no approved stem cell therapy for people with Parkinson’s, there have been some encouraging developments in recent years. And many clinical trials are taking place across the world:
Trial name: Human Embryonic Stem Cell Therapy For Advanced Parkinson’s
Phase: Phase 1
Where: USA and Canada
12 people with Parkinson’s received dopamine-producing cells which had been developed from stem cells. The cells were transplanted into the brain during a surgical procedure. The experimental therapy is called bemdaneprocel or BRT-DA01.
In August 2023, early results from this Phase 1 clinical trial were announced. The results showed that the treatment was well tolerated with no major safety issues or side effects. After 12 months, participants experienced improvements in their Parkinson’s symptoms. Planning is now underway for a Phase 2 study to investigate this promising therapy.
Read the results from the early stage stem cell therapy trial.
Stay up to date with the human embryonic stem cell trial on the ClincialTrials.gov website.
Trial name: STEM-PD
Phase: Phase 1
Where: Sweden (ongoing) and UK (pending approval)
Dopamine-producing brain cells, developed from stem cells, will be transplanted into the brains of 8 people with Parkinson’s via a surgical procedure. The experimental therapy is called the STEM-PD product. The participants will be followed for 36 months, with results expected in 2027.
Read about the approval of the STEM-PD trial back in October 2022.
Stay up to date on the STEM-PD trial on the ClincialTrials.gov website.
Trial name: Mesenchymal Stem Cells as a Disease-modifying Therapy for Parkinson’s
Phase: Phase 2
Where: USA
This study follows a successful Phase 1 trial which took place between 2017 and 2019. The research explores the benefits of stem cells that are derived from the bone marrow of people with Parkinson’s. In the Phase 1 study, 20 people with Parkinson’s received stem cells made from donated bone marrow. The stem cells were delivered to each participant through an injection into the bloodstream. Results showed that the treatment was safe and people on the trial reported an improvement in both movement symptoms and inflammation of cells in the brains.
In the Phase 2 study, 45 people with Parkinson’s received the stem cell treatment. Results are expected in 2024. The trial aims to show whether the therapy is safe and effective as a treatment to slow the progression of Parkinson’s.
Stay up to date on the mesenchymal stem cells trial on the ClinicalTrials.gov website.
Can I take part in a stem cell clinical trial?
Understanding the potential benefits of stem cell therapies for Parkinson’s is only possible if people with the condition take part in clinical trials. However, stem cell therapies are complex and can be invasive. Sometimes trials require participants to undergo brain surgery that cannot be reversed once the study has finished. Making sure that participants are fully prepared and understand what they will be undertaking is of utmost importance from an ethical standpoint.
Due to the complexities of stem cell therapies, and because many clinical trials are still in the early stages of research, many trials select participants rather than actively recruit from the general population.
Currently, there are no stem cell clinical trials that are looking for participants.
We will always share opportunities to get involved in trials through the Research Support Network. You can sign up to receive 2 to 3 emails a month with the latest research news, events and research opportunities.
Sign up to the Research Support Network.
If it sounds too good to be true, it probably is
It’s important to remember that there is currently no known approved stem cell therapy that can stop or reverse Parkinson’s.
Despite this, there are many organisations and agencies that falsely claim they can deliver stem cell treatments for Parkinson’s. These opportunities are often supported by anecdotal evidence only, and lack clinical evidence. They are sometimes described as patient-funded, have a large financial cost, and may require you to travel abroad. When in doubt, please get in touch with us at [email protected].
Stay up to date with stem cell research
Stem cell therapy is an active area of research. To stay up to date, as well as hear about opportunities to get involved in research, sign up to our Research Support Network.