Cell-replacement therapy

Cell-replacement therapy in Parkinson’s involves altering stem cells into dopamine producing nerve cells (or dopaminergic neurons) and transplanting them into a person with Parkinson’s brain to replace dying or lost neurons.

By the time a person is presenting the motor features characteristic of Parkinson’s, and being referred to a neurologist for diagnosis, they have already lost approximately 50% of the dopamine producing neurons in an area of the brain called the midbrain. The dopamine neurons are located in a part of the midbrain called the substantia nigra.

These neurons are critical for normal motor function – without them, movement becomes very inhibited, resulting in the slowness and rigidity associated with Parkinson’s.

And until we have developed methods that can identify Parkinson’s long before these nerve cells are lost and the motor features appear, some form of cell-replacement therapy is required to introduce new cells to take up the lost function.

Cell transplantation represents the most straightforward (but still experimental) method of cell-replacement therapy.

Recent advances in this area of research have shifted away from the old approach to cell transplantation (using dopamine neurons from a donor embryo), and moving towards developing sophisticated methods for growing dopamine-producing neurons in 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 simply an experimental method of replacing lost nerve cells. There are however promising clinical trials happening now which are testing surgical transplantation of dopamine-producing nerve cells into people with Parkinson’s brains – the results of which will be available in the next few years.

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