The importance of the gut-brain axis: Parkinson's findings

    Last semester, I took a course called Neural Disease and Degeneration/Regeneration. In that class, we learned a lot about various neurodegenerative diseases that affect our brains such as Alzheimer's disease (AD), Huntington's disease (HD), Amyotrophic Lateral Sclerosis (ALS), and Parkinson's disease (PD). We learned a lot about the biological foundations of these diseases and their pathologies, and I think it has been one of my favorite classes I have taken at Loyola. As someone who hopes to one day do research on neurodegenerative diseases or to become a medical doctor that can help people with these diseases, I found this class especially fascinating because I have met people who have some of these diseases, and know personally how they can impact one's life.

    I used to work at a nursing home and one of the residents had Parkinson's disease, which is characterized by a buildup of α-synuclein that becomes misfolded and behaves in a Prion-like manner. The symptoms of Parkinson's include tremors, muscle rigidity, difficulty with movement, dementia, difficulty speaking, and a plethora of other things that affect quality of life for a person. In Horsager et al.'s publication from 2020, they highlight that there are two subtypes of Parkinson's: one that begins in the brain with α-synuclein buildup and eventually spreads to the peripheral nervous system, and one that begins in the enteric or autonomic nervous system and then spreads to the brain. Previous studies have found that there are links between the brain and gut microbiota. 

    This picture shows the hypothetical model of brain- and body-first PD, where you can see the difference in progression between the two. 

    This is a potentially important finding in the field of disease research as narrowing down the specific type of Parkinson's for each patient can help provide a more individualized approach to treatment and assistance with the disease. Another important finding that these researchers found is that REM sleep behavior disorder before having Parkinsonism symptoms could indicate body-first Parkinson's. Research into the gut-brain axis is really important as it seems to be more and more prevalent in mood disorders and autism as well as Parkinson's, too. 

Jacob Horsager, Katrine B Andersen, Karoline Knudsen, Casper Skjærbæk, Tatyana D Fedorova, Niels Okkels, Eva Schaeffer, Sarah K Bonkat, Jacob Geday, Marit Otto, Michael Sommerauer, Erik H Danielsen, Einar Bech, Jonas Kraft, Ole L Munk, Sandra D Hansen, Nicola Pavese, Robert Göder, David J Brooks, Daniela Berg, Per Borghammer, Brain-first versus body-first Parkinson’s disease: a multimodal imaging case-control study, Brain, Volume 143, Issue 10, October 2020, Pages 3077–3088, https://doi.org/10.1093/brain/awaa238