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.