Singer-songwriter Neil Diamond’s recent decision to cancel his 50th anniversary tour due to a diagnosis of Parkinson’s disease (PD) shone a spotlight on a condition for which treatment has changed little since Diamond’s first hit Solitary Man in 1966. But while a Parkinson’s disease diagnosis has often seemed to herald an unremittingly gloomy future, research has been moving forward and things are finally changing for the better.
As clinical neurologist Nicola Pavese, Professor of Clinical Neuroscience and Deputy Director of the Clinical Ageing Research Unit at Newcastle University, points out, ‘With increasing understanding of the underlying mechanisms we now have real grounds for optimism.’
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Too little, too late
‘One of the biggest problems with Parkinson’s disease has always been that by the time the classic motor or movement symptoms – things such as shaking (tremor), slowness of movement and rigidity or stiff muscles – are apparent, more than 70% of cells in the area of the brain affected have been lost,’ explains Professor Pavese.
As a result researchers are increasingly turning attention to non-motor symptoms – constipation, sleep disturbance and loss of sense of smell – they believe could be clues to a process that begins years, or even decades, before motor symptoms kick in. Their ultimate aim is to come up with a simple way to pinpoint people at risk of or with Parkinson’s disease at an early stage so they can be prescribed brain-protective drugs – in much the same way statins are prescribed to those with high cholesterol to help prevent a heart attack.
Learn more about anosmia - loss of smell
Parkinson’s disease and gut bacteria link
‘One of the hallmarks of Parkinson’s disease is the build-up of clumps of a rogue protein called alpha-synuclein in the brain,’ explains Professor David Dexter, Deputy Director of Research at Parkinson’s UK. But it is now thought that things may start to go wrong with alpha-synuclein in the gut where changes may be sparked by some, as yet unknown, environmental factor, which then spreads from cell to cell until it reaches the brain. The fact that people with Parkinson’s disease often complain of constipation and other digestive problems years before developing the disease, as well as the recent discovery that Parkinson’s disease patients have different gut bacteria from healthy people, lends weight to this idea.
Learn more about gut disorders
Iron: the Jekyll and Hyde element
In other research, scientists are hunting for clues as to what causes alpha-synuclein build-up in the brain. As Professor Dexter explains, ‘We suspect an accumulation of iron in the brain could be a culprit. Iron is a Jekyll and Hyde element in that while too little can cause health problems, too much can lead to the release of toxic chemicals that attack cells and cause proteins to clump together.’
A large multi-centre European trial to see whether a drug called a chelator, which removes excess iron from the body, could slow down Parkinson’s disease is under way. The drug, deferiprone, is already used to treat iron overload in people with some blood disorders.
‘If deferiprone turns out to be successful in slowing Parkinson’s disease, because it is already on the market it won’t have to go through the lengthy testing new drugs normally need, so it could be available in the foreseeable future,’ observes Professor Pavese. It could be available in three to four years.
Scientists have also found a way to detect iron deposits in several areas of the brainstem of PD patients using a specialised scanning technique, a finding that could lead to a potential test for Parkinson’s disease. Meanwhile, the Michael J Fox Foundation is offering $2m to the first team to develop a radioactive ‘tracer’ to detect alpha-synuclein build-up for use with a type of brain scan called PET (positron emission tomography).
How much iron do you need?
Sleep clue to Parkinson’s disease
Another fascinating – and revealing – recent finding is that people suffering a sleep disturbance in which they ‘act out’ dreams by shouting, thrashing about or lashing out during the rapid eye movement (REM) phase when most dreams occur, often develop Parkinson’s disease. This fits in with observations that clumps of alpha-synuclein gather in parts of the brain that regulate sleep. The condition – known as idiopathic rapid eye movement sleep behaviour disorder (iRBD) – typically affects men aged 50 to 70 years.
In collaboration with Danish and Spanish researchers, Professor Pavese and his team recently discovered that people with iRBD have high levels of brain inflammation, which they think may damage brain cells. The next step is to determine which patients with iRBD go on to develop Parkinson’s disease. ‘We hope to identify a window during which medications to halt or delay the progress of Parkinson’s disease can be given,’ he says.
Loss of smell and Parkinson’s disease
Over the past seven years, Parkinson’s UK has also been funding researchers to devise a simple ‘scratch and sniff’ stick designed to detect the loss of smell people with Parkinson’s often experience. ‘A classic sign is loss of the ability to smell basil on pizza, for example,’ says Professor Dexter. Other smells include banana, liquorice, pineapple, soap, bubble gum, mint, cinnamon, apple and lemon. The trial is due to expand this year. Watch this space!
Learn more about anosmia, or loss of smell
Other studies into Parkinson’s disease
Other scientists are hunting for genetic clues to Parkinson’s disease. Research is focused on finding a way to detect it with a blood test. A study to try to develop a vaccine against alpha-synuclein, designed to trigger the body to generate antibodies that bind and remove small clumps of the protein, is to begin next year.
Elsewhere, researchers are investigating new ways to deliver drugs currently used to treat Parkinson’s disease, in an attempt to avoid side effects. For example, taking the dopamine substitute levodopa by placing it under the tongue may reduce ‘off’ episodes (when the drug doesn’t work properly), which leave people with Parkinson’s disease rigid and unable to move and/or communicate.
With a wealth of studies in the pipeline, we could be on the verge of finding many new ways to screen for, detect and treat Parkinson’s, making the future look so much brighter for those affected.
Learn more about drug treatments for Parkinson's disease
Need to know
What is Parkinson’s disease?
It is a chronic, degenerative neurological disorder that affects an estimated 145,000 people in the UK. Symptoms usually appear after the age of 50. It affects men more than women.
What causes Parkinson’s disease?
The progressive death and depletion of nerve cells in the brain that produce the chemical messenger dopamine, which is involved, among other things, in controlling movement. Exactly what triggers the death of these cells is unknown but it is thought to be due to a combination of both genetic and environmental factors.
What are the signs and symptoms of Parkinson’s disease?
Tremor or shaking, slowed movement and muscle stiffness are the classic trio. Increasingly recognised early symptoms include sleep problems, constipation and a reduced sense of smell. Other symptoms may include mood changes, difficulty swallowing, fatigue, changes in sensation, restless legs and bladder problems. People with Parkinson’s disease often develop memory problems or dementia.
How is Parkinson’s disease treated?
Levodopa, a chemical that is converted to dopamine in the brain, is the mainstay. Other medications may be used instead of or alongside, which either mimic the actions of dopamine or prevent its breakdown in the brain. Deep Brain Stimulation (DBS) involves implanting electrodes into the brain to change some electrical signals that cause symptoms; it can help with disabling tremors, bouts of ‘wearing off’ and other side effects of levodopa.
Three ways to help yourself if you have Parkinson’s disease
A healthy diet rich in wholegrains, vegetables, fruit and pulses can help combat oxidative stress and damage to cells as well as helping reduce the constipation that is often a feature of Parkinson’s disease.
Sleep problems may be due to Parkinson’s disease itself or to symptoms such as tremor or restless legs. Going to bed and getting up at the same time every day, having a wind-down routine, banishing the TV and electronic devices from your bedroom, limiting naps and keeping an eye on your caffeine and fluid intake can all help.
Exercise can help to improve motor symptoms of Parkinson’s disease and ease fatigue. Low-intensity exercise improves walking in people with Parkinson’s disease: yoga, swimming, walking and dance are all good options.
Can you help?
Researchers are looking for both people with Parkinson’s disease and healthy volunteers to take part in trials. Find out more at www.michaeljfox.org or www.parkinsons.org.uk
If you or someone you care for has Parkinson’s disease, call Parkinson’s UK free helpline on 0808 800 0303.
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