Dr. Kristin Andruska, movement disorders specialist, spoke about “Parkinson’s Disease and the Gut” at the Palo Alto PD Support Group’s first meeting at Channing House, 850 Webster St., Palo Alto in October. The inviting new space for the group, is a well-appointed event room in The Channing House, an independent, not-for-profit Life Care retirement community. Public transportation options include the Palo Alto Shuttle and Stanford Marguerite as well as the train to San Francisco or the South Bay. The support group leader, Robin Riddle, reports plenty of free street parking along Webster, Channing (which runs eastbound only), and Homer (which runs westbound only.) I easily found a parking spot directly in front of the Channing House!
Dr. Kristin Andruska is a board-certified neurologist who completed her fellowship in movement disorders at Stanford University. She completed her neurology residency at Washington University in St. Louis, where she also served as the chief resident of education. She was the recipient of the Irwin Levy Prize for Teaching, and the Abdullah M. Nassief Award for Neurology. Dr. Andruska attended the University of Minnesota School of Medicine, graduating from its prestigious Medical Scientist Training Program with both an MD and PhD. She received her undergraduate degree in biology from the University of Texas at Austin.
She has done significant research in neurology. Her graduate work focused on disease models of spinocerebellar ataxia type 1, a neurodegenerative disease, and her post-graduate work in Parkinson’s focused on alpha-synuclein (the major constituent protein of Lewy bodies) and on Parkinson’s genetics. (adapted from www.parkinsonsinstitute.org)
Dr. Andruska began her talk with an alarming fact that between the years 2005 and 2030, the incidence of Parkinson’s disease is projected to double. Many of those diagnosed will have constipation issues. Dr. Andruska described constipation as “a cardinal non-motor symptom of PD,” referring to early Parkinson’s history in 1817, when James Parkinson (Parkinson’s namesake) noticed that PD patients experienced constipation.
Neurons in the gut and the neurons in the brain are connected by a big nerve called the vagus nerve.
The vagus nerve is one of the cranial nerves that connect the brain to the body, including much of the digestive tract.The vagus nerve performs sensory, motor, and automatic functions. Dr. Andruska’s talk focused on clinical research regarding the vagus nerve and how it relates to PD.
Scientists think the vagus nerve may act like a highway for alpha-synuclein to travel from the gut to the brain. Alpha-synuclein is a bad protein that plays a key role in Parkinson’s disease. This protein is the major component of Lewy bodies — protein clumps that develop inside nerve cells and contribute to neurodegeneration. Alpha synuclein in the gut correlates to Parkinson’s non-motor symptoms like constipation, nausea, loss of smell, and digestive difficulty. It also correlates to motor symptoms in PD.
Dr. Andruska reviewed several studies involving the gut and the vagus nerve including a 2015 large Danish epidemiologic study that followed people who had vagotomy surgery. Vagotomy is a surgery that cuts branches of the vagus nerve that connect to the digestive tract and was once a popular way of treating ulcers. In this study, scientists asked whether vagotomy decreases the risk of Parkinson’s disease. In fact, people who underwent full truncal vagotomy had lower risk of developing PD, compared to a matched non-vagotomy group. Researchers found that this risk reduction was durable, even 35 years after surgery. The study supports the theory that Parkinson’s disease may begin in the gastrointestinal tract and spread through the vagus nerve to the brain.
This is an exciting time for gut-brain research in Parkinson’s. More recently, elegant scientific models have investigated the gut-brain axis in Parkinson’s disease. These experiments suggest that not only the vagus nerve, but also gut bacteria, play an integral role in PD. The Parkinson’s Institute is currently hosting a clinical trial about the gut-brain axis in PD, along with others relevant to LRRK2 and GBA mutations, PD biomarkers, and more.
Thanks to Dr. Andruska, the vagus nerve with all of its nooks and crannies has offered us a wealth of information about the relationship of the gut and the brain to PD!
Dr. Kristin M. Andruska is affiliated with the Parkinson’s Institute and Clinical Center. Call (650) 770-0201 for more information or to book an appointment.