Removal of the appendix would protect against the onset of Parkinson’s disease. Without this organ, the risk of contracting this brain disease which causes the destruction of neurons is significantly reduced by 20% in people who have surgery. A figure that even rises to 25% for people living in rural areas. In addition, the disease appears later in operated people.
According to the largest epidemiological study conducted on the subject, carried out by Bryan Killinger of the Van Andel Research Institute in Grand Rapids (United States), preventive removal of the appendix would be a good way to reduce by a quarter the risk of developing Parkinson’s disease.
To obtain this surprising result, the scientists – who already had suspicions about this small growth located at the beginning of the colon – examined the health register of nearly 1.7 million Swedes over a period… of fifty-two years. This work confirms that Parkinson’s disease could sometimes have an intestinal origin and be associated with an environmental cause, through, for example, pesticides or bacteria.
A link between intestinal damage and brain damage already established
The link between intestines and Parkinson’s disease is not new: it appeared about fifteen years ago. The clue: digestive problems often precede the muscle tremors and rigidity that mark the disease by several years. But that’s not all. The toxic aggregates of the so-called alpha-synuclein protein found in diseased neurons first appear in the vagus nerve which innervates the digestive tract. They could then go up to the brain via this nerve, the longest in the human body. The proof was made in rats in 2014: it is possible to induce the disease by inoculating these aggregates into the intestinal wall. Better: in patients with ulcers and whose vagus nerve has been severed to reduce gastric acidity, the risk of declaring the disease also seems to be reduced.
Inflammation increases risk of Parkinson’s and other gut diseases
Parkinson’s disease, like Alzheimer’s or prion diseases, appears to be caused by a protein that takes on a pathogenic form during inflammation. However, such inflammation seems to occur more easily in the appendix, where cells of the immune system responsible for controlling the bacteria of the intestinal microbiota are concentrated. The researchers also found more alpha-synuclein aggregates in the appendix of sick patients than in that of healthy people. Why do these toxic aggregates become pathogenic in some people and not in others? The first track seems genetic. This ground predisposing to inflammation is also found for ulcerative colitis, a colon disease also less common in people operated on for appendicitis.
Killinger BA: The vermiform appendix impacts the risk of developing Parkinson’s disease. Sci Transl Med. 2018 Oct 31;10(465).