2/25/2019 7:55:00 AM Study reveals appendix may play role in developing Parkinson's
Dear Doctor: Is it true that there's a link between the appendix and Parkinson's disease? I thought all an appendix ever does is burst sometimes. Does this mean we should get our appendixes removed, the way our parents used to get their tonsils taken out?
Dear Reader: The appendix has always been a bit of a mystery. It's a narrow pouch, between 2 and 4 inches long, that sits in the lower-right quadrant of the abdomen near where the small and large intestines meet. The fact that the appendix serves no obvious purpose in adults had led to it be considered a vestigial organ. That is, an organ that has lost its function over time. As you point out, the appendix is mainly known for its ability to become inflamed. Since perforation then becomes a risk, which would cause infectious materials to spill into the abdominal cavity, an inflamed appendix is often surgically removed.
Ongoing research has shed new light on the appendix. It's known that during gestation, the appendix makes certain types of cells that play a role in normal fetal development. After birth, the appendix takes on some immune functions. And though it was believed the appendix becomes inert in later adulthood, newer studies suggest that one role of the appendix is to harbor beneficial bacteria that are important to intestinal health. Now, with a study recently published in the journal Science Translational Medicine, a potential link between the appendix and Parkinson's disease has emerged.
Parkinson's is a progressive disorder of the nervous system. It arises due to the loss of cells in the brain that produce dopamine and which control movement. Why this happens is not yet known. The symptoms of Parkinson's disease emerge and progress gradually. They include tremors, muscle stiffness, movement that becomes progressively slower, problems with balance, changes to speech and handwriting, and a loss of facial expression.
The brain cells of many people with Parkinson's have been found to contain a protein called alpha-synuclein. This protein clumps together into structures known as Lewy bodies, and is believed to be so toxic to brain cells that it causes their death. This same protein has also been found in the intestines of Parkinson's patients. That's significant because some researchers believe that the vagus nerve, which runs from the gut to the brain, may serve as a pathway along which the toxic proteins can travel.
Because certain gastrointestinal symptoms often precede the motor effects of Parkinson's disease, researchers specifically designed this latest study to explore the potential of a gut-brain connection. In one section of the study, which analyzed the long-term hospital data of 1.7 million Swedish individuals, they found that people who underwent an appendectomy as young adults had a 20 percent lower risk of developing Parkinson's decades later. The study also found accumulations of alpha-synuclein, the protein mentioned earlier, in 46 out of 48 appendixes of healthy individuals.
As to whether all of this points the way to preventative appendectomies, the answer is no. While this research does open up new avenues of study into the causes of Parkinson's disease, it doesn't reach any conclusions. For now, unless it's inflamed, the appendix stays.
Eve Glazier, M.D., MBA, is an internist and associate professor of medicine at UCLA Health. Elizabeth Ko, M.D., is an internist and assistant professor of medicine at UCLA Health. Send your questions to email@example.com, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.