Parkinson's disease has long been considered a brain disease, but several studies have pointed to the digestive system. A study published Wednesday in the United States is particularly interested in the small body that is considered unnecessary attachment.
The authors of this study, based on the medical data of 1.7 million Swedes followed for half a century, found that those who had removed the appendix early in life had a risk of developing Parkinson's disease by 19%. The effect seems to be specific to Swedes living in rural areas. For them, the risk is reduced by 25%, while in urban areas risk reduction can not be observed.
In the case of those who developed Parkinson's disease, researchers found that appendectomy (removal of the attachment) was linked to an average of three and a half years on average, says senior author Viviane Labrie, of the Van Andel Research Institute in Michigan, during a conference call with the press on Tuesday.
"Our work suggests that the annex could play a role in the beginning of Parkinson's disease," she explained, noting that this role was probably not exclusive.
Parkinson's patients also suffer from gastrointestinal problems such as constipation, a decade or more before symptoms such as tremors and other engine problems. This has caused the scientific community to be interested in the digestive system.
The attachment is a storage site for intestinal bacteria and also plays a role in the immune response. It is also the "reservoir" of a key protein in Parkinson's disease called alpha-synuclein, especially in an abnormal form.
But this protein is abundant in the attachment to all, sick or not. This suggests researchers that the abnormal protein sometimes succeeds in flying from the appendage to the brain, where it would cause damage.
"This protein does not like to stay in one place," said Viviane Labrie. "She may move from neuron to neuron".
And just a nerve, the vagus nerve, connects the digestive tract to the brain. Experiments have shown that the protein can take this pathway.
"If it goes into the brain, it can penetrate and develop until it has neurotoxic effects that can lead to Parkinson's disease," said the researcher.
The authors of the study warned the press that it was not advisable to recommend anyone to remove the attachment. "We do not say that if you have removed, you will not have Parkinson's disease," warns Viviane Labrie.
But this work provides a further clue to the role of the small organ, which one day could lead to treatments, to neutralize this reservoir.
At the moment, a causal link has not been established. As is the case with studies of this type, many factors that can not be explained explain the difference between those who have been ablated and others.