04.08.2021

IBD sufferers are 30% more likely to develop Parkinson’s

People with irritable bowel disease are at greater risk of developing Parkinson’s than others, but treating the gut trouble early may reduce the threat, a new study finds.

Scientists previously discovered that Parkinson’s and IBD may be linked by a protein that builds up in the brains and guts of people who suffer each respective disease.

Researchers at the Icahn School of Medicine at Mount Sinai further confirmed the link, finding that people with IBD were at a nearly 30 percent higher risk of Parkinson’s.

But the study provided some hope as well: taking certain anti-inflammatory drugs for IBD cut Parkinson’s risks back down by almost 80 percent.

People who suffer from irritable bowel syndrome are at 30 percent greater risk of developing Parkinson's but treating the gut disease early could prevent Parkinson's, a study suggests

People who suffer from irritable bowel syndrome are at 30 percent greater risk of developing Parkinson’s but treating the gut disease early could prevent Parkinson’s, a study suggests

About one percent of people over the US will be affected by Parkinson’s disease after the age of 60, causing tremors and loss of cognition.

Second only to Alzheimer’s, Parkinson’s is a common affliction, but its causes remain poorly understood.

Scientists suspect that the disease arises due to a combination of genetic and environmental factors which cause neurons that produce the key neurotransmitter, dopamine, to die off.

Doctors are still not equipped with Parkinson’s-specific diagnostics, and instead typically identify the disease by its symptoms and the presence of Lewy bodies – clumps of a particular protein found in the brains of Parkinson’s sufferers.

This tough protein, called alpha-synuclein, is inside every Lewy body, and is too difficult for cells to be able to break down. Much current Parkinson’s research is focused on these proteins.

Systemic inflammation – a kind of immune system overreaction – is thought to be linked to Parkinson’s as well.

Scientists believe that inflammation can kill of the dopamine-producing neurons, contributing to the development of Parkinson’s.

The Mount Sinai researchers also published their discovery in January that people with IBD and those with Parkinson’s have mutations in a particular area on their genome.

Someone suffering from either disease has impaired autophagy, a biological process that helps to get rid of cellular waste and damaged cells.

‘Once it is impaired, [that waste] all stays in the cell and damages it and the proteins associated with Parkinson’s build up,’ explains first study Dr Inga Peter.

After discovering this biological link between the diseases – systemic inflammation – Dr Peter and her team thought: ‘Why don’t we look at medications that aim to reduce systemic inflammation to see if they would prevent Parkinson’s?’

That question was the foundation of the new study.

The researchers looked at data on more than 144,000 irritable bowel disease patients and compared them to 720,090 people without the disease.

As expected, they found that Parkinson’s was 28 percent more common among those with IBD than those without the disease.

But when IBD patients were treated with anti-tumor necrosis factor (anti-TNF) therapy, a common drug used to treat the condition, their risks of developing Parkinson’s were 78 percent lower – not just than other IBD patients, but than the general population’s risks.

‘By reducing inflammation, we could potentially prevent Parkinson’s going forward,’ says Dr Peter.

Despite knowing that inflammation raised Parkinson’s risks, doctors previously thought that the drug would not be effective against Parkinson’s because it is not able to cross the blood-brain barrier.

But the new observations from Mount Sinai suggests one of two things, Dr Peter says: the drugs ‘don’t have to cross the barrier, reducing systemic inflammation is good enough…or it’s possible that in patients with IBD, the blood-brain barrier is leaky, like their guts are leaky.’

Either way, ‘the drugs are not harmless,’ she says.

‘They are immunosuppressants, because IBD is the [immune system] overreacting to normal processes and it needs to calm down,’ she says.

Drugs that suppress the immune system leave patients vulnerable to other infections, however.

But, it may be the best hope for preventing Parkinson’s, for which ‘there are currently only drugs to limit or mitigate the symptoms, and nothing that really targets the mechanism of the disease,’ says Dr Peter.

She and her team need next to work out ‘who develops Parkinson’s among IBD patients,’ so that they know who could benefit from the possible preventative treatment, she says.

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