Spread of Parkinson's to transplanted brain cells observed

Cell transplants can be used to treat a whole host of diseases, offering patients hope of a better and longer life, however, in the case of Parkinson’s, researchers from Lund University,
Sweden, and University College London, UK, have found new evidence to suggest that the disease can eventually spread into healthy grafted cells.

The findings were recently published in the journal Nature Medicine.

In earlier studies, researchers from Lund University and Lund University Hospital found that cells transplanted into the brain of a patient suffering form Parkinson’s can survive for a period
of 10 years. While most of the grafted cells are functionally impaired after this time, patients can still feel long-term symptomatic relief. In the latest study, the researchers found that the
grafted cells can in fact survive a little longer, for as much as 16 years.

Parkinson’s is caused when brain cells that produce a chemical called dopamine die off. Dopamine plays a key role in co-ordinating body movement.

‘Previous studies have shown that transplanted dopamine cells can clearly improve speed of movement, reduce rigidity and the need for medication for at least a decade,’ explains Jia-Yi Li,
Associate Professor of Neurobiology, Neuronal Survival Unit at Lund University. ‘We now see that they also are alive in large numbers, which is very exciting.’

However, Parkinson-like features do eventually appear in the healthy cells. The researchers made this discovery after studying the cases of two patients who had lived for between 11 to 16 years
following a neuron cell transplant. When both patients died (from causes unrelated to grafting), the researchers found that the disease had spread.

‘Our results suggest that key features of Parkinson’s disease pathology slowly transfer from the patient’s brains to the healthy nerve cells in the transplant’, says Professor Patrik Brundin,
Head of the Neuronal Survival Unit at Lund University.

The discovery is expected to help researchers to better understand the disease’s pathogenesis, particularly how it can propagate from host to graft cells. ‘We still do not know the precise
cellular mechanisms, but the findings open up new exciting lines of research. If we can crack the mechanism, we may be able to devise treatments that prevent or slow disease progression in the
future,’ adds Professor Brundin.

In the meantime, the researchers say that cell therapy remains a viable tool. ‘Although we have now found that the grafted cells may be affected by the disease, the pathological changes appear
late,’ says Professor Olle Lindvall of Lund University Hospital. The transplantation of dopamine cells, which are likely to be produced from stem cells, will continue to play an instrumental
role in the treatment of patients with Parkinson’s, according to the professor.

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https://www.nature.com/