A recent study conducted by scientists from the Icahn School of Medicine at Mount Sinai, NY, uncovers fresh details about the links between Parkinson’s disease and inflammatory bowel disease (IBD). In agreement with previous work, they show that variants of a gene called LRRK2 are important in both conditions. They also identify new genes and pathways that Parkinson’s and IBD share.
The authors hope that uncovering these common biochemical pathways might provide new insights into potential treatments for both conditions. Parkinson’s is a neurodegenerative condition which affects a region of the brain known as substantia nigra. As it progresses, there is a reduction in dopamine, which produces symptoms that include stiffness and tremors.
However, experts have long known about links between Parkinson’s and the gut. More recently, some research has shown that people with IBD have an increased risk of developing Parkinson’s later in life. Scientists want to understand why.
One of the hallmarks of Parkinson’s disease is Lewy bodies within the brain which are mostly formed of a protein known as alpha-synuclein. This protein buildup is a tell-tale sign of Parkinson’s, but it is unclear whether Lewy bodies themselves are toxic or the buildup is part of the body’s defense mechanisms.The presence of alpha-synuclein in the gut’s nervous system supports the hypothesis that Parkinson’s pathology might start in the gut and spread to the brain via the vagus nerve.
Beyond protein buildup, previous research has also noted associations between alterations in a gene called LRRK2 and both IBD and Parkinson’s. To date, LRRK2 is the most well-established genetic link between the two conditions. 14 genes, including LRRK2, as potential candidates for further validation in clinical settings for future targeted therapies were identified. Given the shared mechanisms underlying IBD and Parkinson’s, researchers want to test whether medications used for one of these conditions could apply to another leading to drug repurposing. Along these lines, previous studies have shown that treatment with anti-TNF therapy, which is a common treatment for IBD, reduces the risk of developing Parkinson’s.
According to research, this suggests that “reducing peripheral inflammation could be a prudent way to prevent Parkinson’s. Optimizing these drugs and testing them in clinical trials would be an important next step. Research is ongoing into the use of non-steroidal anti-inflammatory drugs (NSAIDs), corticosteroids, and other anti-inflammatory agents to slow Parkinson’s progression.
For instance, anti-inflammatory drugs or autophagy enhancers could be explored for their efficacy in both IBD and Parkinson’s. Although scientists have much more work to do, developing a deeper understanding of how IBD and Parkinson’s work is an important next step along the path to better treatments for both.
