Parkinson’s and stem cell therapy

Although the underlying cause of Parkinson’s is unknown, scientists do know that Parkinson’s results from the loss of dopamine-producing nerve cells (neurons) in an area of the brain called the substantia nigra. Therefore, researchers are looking into the replacement of those cells as a potential treatment method.

What is cell replacement therapy?

Cell replacement therapy in Parkinson’s involves altering stem cells – special human cells that have the ability to develop into many different cell types – into dopamine-producing neurons. These new dopamine neurons can then be transplanted into the brain of a person with Parkinson’s to replace the dying or lost neurons.

Why is cell replacement therapy a possible treatment for Parkinson’s?

By the time a person is diagnosed with Parkinson’s, they have already lost at least 60% of the dopamine-producing neurons from the area of the brain most affected by Parkinson’s – the substantia nigra. Located in the midbrain, the neurons here are critical for normal motor function as they produce dopamine – a type of neurotransmitter, or molecule that neurons use to communicate with one another. Without these neurons, dopamine levels are reduced, and movement becomes challenging, resulting in the slowness and rigidity associated with Parkinson’s.

Until we have developed methods that can slow or prevent the loss of these neurons in Parkinson’s, cell replacement therapy offers hope by introducing new cells to replace the loss of function. Historically, this area of research was focussed on transplanting dopamine neurons from a donor embryo; however, more sophisticated methods have since been developed, including growing dopamine-producing neurons in the lab through cell culture.

It is important to understand that, by itself, cell transplantation is not curative and will not halt the progression of the condition. It is an experimental method of replacing lost nerve cells. There are, however, promising clinical trials happening which are testing surgical transplantation of dopamine-producing nerve cells into people with Parkinson’s. One of these, STEM-PD, released an update on their ongoing phase 1 trial in mid-2024.

Our Research Update meeting in 2023 highlighted the recent updates in the field of cell replacement therapies for Parkinson’s with Professor Roger Barker. Watch this recording now: