Parkinson’s disease is a neurological disorder with symptoms that become more severe over time. It affects about 1% of people ages 60 years and older in industrialized nations. The exact cause of the disease isn’t known, but experts believe that both genetic and environmental factors play a role.

Parkinson’s disease causes neurons to die in certain parts of your brain, leading to a decrease of dopamine. Dopamine is a neurotransmitter. Cells in your brain release dopamine as a way of sending signals to other nearby cells.

When you have Parkinson’s, a decrease in dopamine activity can lead to such symptoms as:

There’s no cure for Parkinson’s disease. But over the past few decades, researchers have been studying stem cell therapy to provide better treatment options.

Read on to learn more about current and future developments in using stem cell therapy to treat Parkinson’s disease.

Stem cells are special because they’re undifferentiated, meaning they have the potential to become many types of specialized cells.

You might think of stem cells as natural resources for your body. When your body needs a specific type of cell — from bone cells to brain cells — an undifferentiated stem cell can transform to fit the need.

There are three main types of stem cells:

  • Embryonic stem cells: These cells are pluripotent, meaning they can transform into the many types of cells found in your body. As the name suggests, they’re found in embryos.
  • Somatic stem cells: Also called adult stem cells, these mostly perform repair functions. They can still transform, but not into as many types of specialized cells as embryonic stem cells can.
  • Induced pluripotent stem cells (iPSCs): These stem cells are made by genetically changing cells that have already matured.

Stem cell therapy is the use of stem cells — usually from a donor, but sometimes from your own body — to treat a disorder.

Because Parkinson’s disease leads to the death of brain cells, researchers are trying to use stem cells to replace brain cells in the affected areas. This could help treat the symptoms of Parkinson’s disease.

Researchers are exploring various approaches to use stem cells to treat Parkinson’s disease.

The current idea is to introduce stem cells directly into the affected areas of your brain where they can transform into brain cells. These new brain cells could then help regulate dopamine levels, which should improve the symptoms of the disease.

It’s important to note that experts believe this would only be a treatment for Parkinson’s disease and not a cure.

While stem cell therapy has the potential to replace the brain cells destroyed by Parkinson’s disease, the disease would still be present. Parkinson’s disease would likely destroy the implanted stem cells eventually.

It’s unclear right now whether stem cell therapy could be used multiple times to continue to reduce symptoms of Parkinson’s disease or if the effect would be the same after multiple procedures.

Until the discovery of the process of creating iPSCs, the only stem cell therapies for Parkinson’s disease required the use of embryonic stem cells. This came with ethical and practical challenges, making research more difficult.

After iPSCs became available, stem cells have been used in clinical trials for many conditions involving neural damage with overall mixed results.

The first clinical trial using iPSCs to treat Parkinson’s disease was in 2018 in Japan. It was a very small trial with only seven participants. Other trials have been completed using animal models.

So far, trials have shown improvement to symptoms affecting movement as well as nonmotor symptoms such as bladder control.

Some challenges do arise from the source of the stem cells.

Stem cell therapy can be thought of as being similar to an organ transplant. If the iPSCs are derived from a donor, you may need to use immunosuppressant drugs to prevent your body from rejecting the cells.

If the iPSCs are derived from your own cells, your body might be less likely to reject them. But experts believe that this will delay stem cell therapy while the iPSCs are made in a lab. This will probably be more costly than using an established line of tested iPSCs from a donor.

There are many symptoms of Parkinson’s disease. They’re often rated using the Unified Parkinson’s Disease Rating Scale (UPDRS) or the Movement Disorder Society’s updated revision of that scale, the MDS-UPDRS.

Clinical trials today are generally looking to significantly improve UPDRS or MDS-UPDRS scores for people with Parkinson’s disease.

Some trials are testing new delivery methods, such as intravenous infusion or topical applications. Others are looking to determine the safest number of effective doses. And other trials are measuring overall safety while using new medical devices in stem cell therapy.

This is an active area of research. Future trials will help narrow down the most safe and effective approach to stem cell therapy for Parkinson’s disease.

Clinical trials are usually conducted in three phases. Each phase adds more participants, with the first phase usually limited to a few dozen people and several thousand in the third phase. The purpose is to test the treatment’s safety and effectiveness.

Clinical trials testing stem cell therapy for Parkinson’s disease are still in the early phases. If the current trials are successful, it will likely still be 4 to 8 years before this treatment is widely available.

Participating in clinical trials

Ongoing clinical trials for treating Parkinson’s disease using stem cell therapy may be available in your area. If this is something you’re interested in, check back regularly, as new trials may be added later.

Be sure to mention your intentions to a doctor or healthcare professional as well. They may have additional information specific to your circumstances.

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The goal of stem cell therapy for Parkinson’s disease is to replace destroyed brain cells with healthy, undifferentiated stem cells. These stem cells can then transform into brain cells and help regulate your dopamine levels. Experts believe this can relieve many of the symptoms of Parkinson’s disease.

This therapy is still in the early stages of clinical testing. Many trials are either proposed, currently recruiting, or already active. The results of these trials will determine how soon stem cell therapy might become widely available as a treatment for Parkinson’s disease.

At the moment, it’s not believed that stem cell therapy will cure Parkinson’s disease. But it might be an alternative to existing treatments such as drug therapies and deep brain stimulation.