SAN DIEGO, CA — The community of microorganisms living in the human gut, known as the gut microbiome, is increasingly recognized as playing a pivotal role in metabolic conditions such as obesity and neurological diseases including Parkinson’s disease. The findings were presented at Neuroscience 2022, the annual meeting of the Society for Neuroscience and the world’s largest source of emerging news about brain science and health.
The human body hosts trillions of microbes, and the gut microbiome in particular appears to play an important role in human health and disease through several mechanisms. Advances in tools and techniques are allowing researchers to probe how interactions between our gut microbes, environment, and biology could impact a variety of health conditions.
Today’s new findings show that:
- Early life adversity is associated with gut microbial imbalances, inflammation, and brain structure differences with BMI (Johnny Figueroa, Loma Linda University)
- Gut microbiota changes may contribute to abnormally folded proteins traveling from the colon to the brain, leading to the loss of dopaminergic neurons in Parkinson’s disease (Yoon-Seong Kim, Rutgers-Robert Wood Johnson Medical School)
- Oral pesticide exposure can alter dopamine pathways in the brain and lead to changes in the gut microbiome that are relevant to Parkinson’s disease (Timothy R. Sampson, Emory University)
“The neuroscience research presented today illustrates that, when it comes to metabolic and neurological disorders, we cannot target only the brain. Everything that happens in the gut has an impact on the brain,” says Sonia Villapol, assistant professor of neurosurgery at Houston Methodist Research Institute, who studies brain recovery through the lens of peripheral mechanisms, including the gut microbiome. “A better understanding of interactions between the gut and the brain will bring great opportunities for the diagnosis, treatment, and prevention of diseases.”
This research was supported by national funding agencies including the National Institutes of Health and private funding organizations. Find out more about the gut microbiome and the brain on BrainFacts.org.
Press Conference Summary
- Varied mechanisms link the microbes in the gut with the brain, making the gut microbiome an important player in some metabolic and neurological disorders.
- Clinical studies in humans and research with animal models are increasingly finding a role for the gut microbiome in health conditions including obesity and Parkinson’s disease.
Interactions of Early Life Adversity and Brain-Gut Alterations Predict Obesity-Related Complications
Johnny Figueroa, jfigueroa@llu.edu, Abstract 519.13
- Researchers investigated biological factors mediating the potential connections between early life adversity and body mass index in a sample of primarily Hispanic adults. Hispanic Americans are disproportionately affected by obesity, with a rate approaching 50%.
- The researchers showed gut-related factors, inflammatory biomarkers, and neurobiological structures including the hippocampus interact may play a role in the increased body mass index frequently found in individuals exposed to early life adversity.
- The findings reveal potential predictive indicators of early stress-induced obesity. The researchers hope these predictors could prove a target for personalized diet and probiotics to help reduce health disparities.
A New Parkinson’s Disease Model - Intracolonic Rotenone Causes Alterations of Gut Microbiota and Induces α-Synuclein Aggregation in the Brain
Yoon-Seong Kim, yk525@rwjms.rutgers.edu, Abstract 042.15
- Parkinson’s disease is a progressive neurodegenerative disease characterized by the loss of dopaminergic neurons and associated with the abnormal aggregation of the protein α-synuclein in the brain. One hypothesis posits that abnormal α-synuclein can spread from the gut to the brain.
- Researchers developed a mouse model of Parkinson’s disease by treating mice with intracolonic injections of rotenone, an insecticide and herbicide. The treatment led to motor deficits accompanied by loss of brain dopaminergic neurons. - Rotenone-treated mice also showed increased α-synuclein expression in the gut, colon, and brain. They also experienced changes in their gut microbiomes that persisted for up to 22 weeks after treatment.
- Results indicate that abnormal α-synuclein may originate in the colon and move to the brain, leading to dopaminergic neuron loss and motor problems, and that gut microbiota may contribute to this process.
Low-Dose, Oral Insecticide Exposure Impairs Gastrointestinal Function and Disrupts Nigrostriatal Dopamine Circuitry in Mice
Timothy R. Sampson, trsamps@emory.edu, Abstract 447.14
- Emerging associations between Parkinson’s disease, pesticide exposure, and gastrointestinal abnormalities have led to the idea that some cases of the disease may be triggered from within the gut after oral pesticide exposure.
- Mice were treated orally with deltamethrin, an insecticide that disrupts dopamine signaling.
- Deltamethrin treatment resulted in altered motor behaviors and changes in dopamine pathways. In male mice only, deltamethrin exposure triggered intestinal behaviors indicative of constipation.
- Results suggest that oral exposure to deltamethrin in adulthood can lead to functional and molecular changes in the gut and brain relevant to Parkinson’s disease