Your appendix may be useless, but it could give you Parkinson’s

It has recently been reported that Parkinson’s Disease (PD) may stem from the appendix, not the brain, and that having your appendix removed earlier in life can reduce the likelihood of later developing the condition. Parkinson’s is a progressive neurological condition that worsens over time and affects around one in every 350 adults in the UK. Symptoms include: tremors, slow movement and various psychological symptoms such as depression and memory problems.

Up until now it was thought to originate from a build-up of alpha- synuclein protein, a toxic compound, that forms clumps and aggregates that spread along neurons. This build-up results in a loss of nerve cells and a reduction of dopamine in the region of the brain (the substantial nigra) that controls body movement. However, increasing evidence shows that this process may begin in the nerves of the gut.

Dr Viviane Labrie of the Van Angel Research Institute in Michigan carried out an investigation by looking at healthcare records of 1.6 million Swedish people over 52 years. The risk of developing PD for individuals who had undergone appendectomies (the removal of the appendix) as young adults decreased by 19.3 per cent compared to the general population.

Further studies show that individuals living in rural areas are at a greater risk for PD, possibly due to a greater exposure to pesticides that may contribute to the development of the disease. This study was included in the investigation and the results showed that the risk of developing PD had decreased by 24 per cent in rural residents who had an appendectomy as young adults. There was no benefit for urban city dwellers. Furthermore, PD onset was shown to be delayed on average by 3.6 years in individuals who had an appendectomy at least 30 years before developing the condition.

However, findings show that once an individual had developed PD, the severity of the symptoms were not altered between those who had had an appendectomy and those who had not. This implies that the appendix might be a precursor to a clinical onset of symptoms.

Labrie’s team analysed appendixes taken from subjects with and without PD. They found aggregates of clumped a-synuclein in the organ’s fibres in nearly all of the individuals (46 of the 48 subjects examined). This study showed that the appendix contains an abundance of proteins that are analogous to the abnormal proteins that are found in the nerve cells of patients with Parkinson’s.

Despite being considered a ‘useless’ organ of our evolutionary past, these results signify that the appendix could be the source of pathogenic forms of a-synuclein, that travel along the vagus nerve (the main nerve that connects the gut to the brain) and may potentially contribute to PD initiation and development. If this is the case, further research investigating new ways to prevent excessive a-synuclein aggregates in the appendix could be applied as an alternative form of therapy to combat Parkinson’s disease.

The appendix clearly does not explain the whole story, however; otherwise, removing it would prevent all cases of Parkinson’s. Therefore people should not rush to have their appendix removed. “We’re not advocating appendectomy as a form of protecting against Parkinson’s disease”, said Labrie, as the study has only indicated an association, not a cause-and-effect relationship between individuals who receive appendectomies and a reduced risk of Parkinson’s.

Image: Hey Paul Studios via Flickr

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