Parkinson’s is a progressive neurological condition, affecting over 150,000 people in the UK. It is considered to be the fastest growing neurological condition in the world, with the number of people affected expected to double by 2050.
The condition is characterised by the build-up of a protein known as alpha-synuclein, in the form of clumps called ‘Lewy bodies’. Lewy bodies contain misfolded alpha-synuclein, and are found in areas of the brain where neurons die in Parkinson’s, including the substantia nigra.
Neurons in the substantia nigra are responsible for producing dopamine, a brain chemical that controls movement, as well as other bodily functions. When these neurons begin to die, the brain doesn’t have enough dopamine. People who have Parkinson’s therefore typically experience motor symptoms such as tremor, rigidity and slowness of movement.
People with Parkinson’s may also experience a range of non-motor symptoms, including pain, memory problems, and mental health issues.
Parkinson’s and dementia
Up to 80% of people who have Parkinson’s will eventually develop dementia. Parkinson’s dementia is very similar to another type of dementia, called dementia with Lewy bodies. The protein alpha-synuclein is implicated in both, Lewy bodies are present and the two conditions share the same symptoms.
The main difference is the timing of when symptoms start. If motor symptoms have been present for at least a year before symptoms of dementia, a diagnosis of Parkinson’s dementia will be given, but if dementia symptoms start at the same time or before motor symptoms, dementia with Lewy bodies will be diagnosed. The two conditions are sometimes grouped under an umbrella term of ‘Lewy body dementia’.
What causes Parkinson’s?
We don’t yet know exactly what causes Parkinson’s, but scientists believe it is a complex mix of age, genetic and lifestyle factors. Age is the biggest risk factor, and research has identified over 90 genes that can increase the risk of developing Parkinson’s.
There is also some evidence to suggest that exposure to certain environmental risks, such as some pesticides, can cause Parkinson’s. Conversely, studies have reported a reduced risk associated with certain lifestyle factors, such as physical activity.
How is Parkinson’s treated?
Currently, Parkinson’s is treated through drugs that help to manage the symptoms of the condition. These therapies will either increase the amount of dopamine in the brain, act as a substitute for dopamine, or prevent the breakdown of dopamine. As the condition progresses, treatment will become less effective as there are fewer neurons for the dopamine to act on.
After medication stops working, some people may be eligible for deep brain stimulation, a type of surgical treatment where electrodes are implanted into the brain to help with motor symptoms. There are currently no available therapies that slow or stop Parkinson’s from progressing, though research is ongoing to develop effective disease modifying therapies.
How are UK DRI researchers helping to advance the field of Parkinson’s research?
Earlier diagnosis
Dr Cynthia Sandor (UK DRI at Imperial) is working on ways to detect Parkinson’s at an earlier stage of the disease. By the time someone starts experiencing symptoms of Parkinson’s, they have already lost 50% of neurons in the substantia nigra, so earlier diagnosis is key to ensuring future treatments can be administered when they are most likely to be effective. A study conducted by Ann-Kathrin Schalkamp, a member of Dr Sandor’s lab found that data from smart watches could detect Parkinson’s years before a clinical diagnosis. Dr Sandor is building on these findings, looking at digital and blood biomarkers, and how these can be harnessed to help diagnose Parkinson’s earlier.
Fixing brain connections
Dr Dayne Beccano-Kelly (UK DRI at Cardiff) studies communication between neurons in Parkinson’s, using model systems. His team aim to decipher how miscommunication arises at the earliest stages of Parkinson’s, and find new ways of correcting it before significant loss of cells in the brain, and symptoms appear.
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Deciphering Parkinson’s one cell at a time
Prof Mina Ryten (UK DRI at Cambridge) is harnessing genetics and other detailed molecular analyses to understand why Parkinson’s starts and how it progresses. The Ryten lab focuses on the human brain transcriptome – a readout of all the genes present in cells in the brain. By studying the transcriptome at the level of individual cells in health and disease, Prof Ryten hopes to identify the cells, genes and processes which drive Parkinson’s and could reveal new therapeutic targets.
Brain first or body first?
Dr Tim Bartels (UK DRI at UCL) and his team are looking into the link between the gut-brain axis, and Parkinson’s. Emerging evidence suggests that in some people, Parkinson’s starts in the brain, whilst in others, it begins in the enteric nervous system of the gut. Dr Bartels’s team are looking into whether it is possible to detect Parkinson’s in the gut at the very earliest stage, before it has begun to affect the brain.
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Source: Parkinson's UK & Cure Parkinson's
Article published: 11 April 2024
Banner image: Peter Kindersley via Centre for Ageing Better