A new angle on Parkinson’s

There is fresh hope for the treatment of the world’s fastest-growing neurological disease following the discovery that the condition very probably exists as two completely different types.

This suspicion had been simmering for a while, mainly due to the fact that Parkinson’s doesn’t seem to follow the same trajectory in everyone it affects. Parkinson’s is associated with the loss of nerve cells in parts of the brain that help control movement. Now, however, evidence is solidifying of “brain-first” and “body-first” versions of the disease, where the latter involves neuron loss starting outside the brain before working its way into it. Nerve cell depletion in the heart and gut has been observed in persons apparently disease-free, but who subsequently went on to suffer from the condition. 

Neuron die-off is caused by the proliferation of a misfolded form of the protein alpha-synuclein, a protein critical to controlling the release of neurotransmitters such as dopamine at synapses between neurons where communication happens. These misfolded proteins clump in neurons and slowly kill them. It is now widely believed that the nervous system between the gut and brain can carry the misfolded proteins to vulnerable parts of the brain. Some post-mortem analyses of people who had died with Parkinson’s showed the misfolded protein only in the brain stem, strongly implying that it had just reached the brain from somewhere else.

But what about treatment? Under examination now is the treatment of species of the gut microbiome, which are frequently either abnormally elevated or depleted in people with Parkinson’s. This raises the tantalising idea that transplanting healthy bacteria into the gut can be a treatment for symptoms in people with “body-first” Parkinson’s.

More studies and trial testing are under way. But there is a belief in the scientific community that is revolutionising our understanding of the disease. More effective treatment will then be offered by “subtyping” while offering tailored treatments to subgroups with different onsets of the condition.