CHICAGO -- Research on gut-brain communication via the immune system may help in the development of novel treatments for neurodegenerative diseases. The findings were presented at Neuroscience 2019, the annual meeting of the Society for Neuroscience and the world's largest source of emerging news about brain science and health.
There is now an increased understanding of the connection between the almost 100 trillion microbes in our intestine (i.e., the "gut" microbiome) and the brain. Recent studies suggest that intestinal bacterial imbalance is connected to disorders like allergies, obesity, cancer, and neurodegenerative diseases like Alzheimer's Disease (AD) and traumatic brain injury (TBI). As this relationship becomes better understood, so too does the potential to use this connection to ameliorate the pathology of neurological diseases.
Today's new findings show that:
- Changes to the gut microbiome induced by antibiotic treatment reduce amyloid beta plaque in the brain and alters the brain's microglia, suggesting a relationship between changes in the microbiome and AD pathology. (Hemraj Dodiya, University of Chicago Medicine)
- Intestinal imbalances in mice with AD improve with a health-promoting probiotic that affects bacterial byproducts and brain activity. (Harpreet Kaur, University of North Dakota)
- A novel therapy for TBI uses a probiotic treatment to prevent gut bacteria loss as well as memory deficits in mice. (Wellington Amaral, University of California, Los Angeles)
- Diet-induced obesity in mice alters immune signaling that controls the permeability of the blood-brain barrier and may be a key mediator in AD neuroinflammation and neurodegeneration. (Malu Tansey, University of Florida Health)
"These are important contributions to our understanding of the complex relationship between the gut and the brain," said press conference moderator Jane A. Foster, PhD, an associate professor at McMaster University who studies the role of immune-brain and gut-brain interactions on neurodevelopment. "The evidence suggests that manipulating gut health can also impact brain health in relevant ways, and that microbiome balance corresponds to improved immune functioning. Continued research in this area has the potential to give us more treatment options for neurodegenerative diseases in the future."
This research was supported by national funding agencies including the National Institutes of Health and private funding organizations. Find out more about Alzheimer's Disease, traumatic brain injury, and other cognitive disorders on BrainFacts.org.
Related Neuroscience 2019 Presentation
Minisymposium: The Gut-Brain Axis in Health and Brain Disease
Sunday, Oct. 20, 1:30 - 4:00 p.m., Room S406A
Gut-Brain Press Conference Summary
- Overall, these studies dive deep into the relationship between the gut and the brain and isolate factors that play an important part in their communication. Additionally, the research focuses on when, how, where, and why the gut and brain interact, and whether the relationship can be effectively manipulated. There is evidence to suggest that a greater intestinal balance and better overall health improve brain function in relevant ways.
Sex-specific Effects of Microbiome Perturbations on Cerebral Aβ Amyloidosis and Microglia Phenotypes in an Alzheimer's Transgenic Mouse Model
Hemraj Dodiya, firstname.lastname@example.org, Abstract 106.01
- The gut microbiome plays a role in "training" the brain's immune cells, or microglia, which strengthen brain circuitry and remove waste products. Changing the microbiome can alter the development and function of microglia.
- In a mouse model with amyloid beta, antibiotic treatment was used to change the microbiota in the gut. In male mice, these changes corresponded with reduced amyloid-beta pathology and altered microglia characteristics; there was no change in female mice. Reversing the antibiotics' effects led to a reversal of symptoms.
- The results suggest that the gut microbiome causes changes in microglia, neuroinflammation, and Alzheimer's pathology in a sex-specific manner.
Effects of Probiotic Supplementation on Serum and Brain Short Chain Fatty Acids in the App NL-G-F Mouse Model of Alzheimer's Disease
Harpreet Kaur, email@example.com, Abstract 106.08
- The relationship between gut microbes and the mechanisms by which they impact health are unknown. Researchers investigated bacterial byproducts called short-chain fatty acids (SCFAs) that are potentially involved in brain-gut communication and anti-inflammation.
- In a mouse model with Alzheimer's disease, researchers used health-promoting probiotics to test if this treatment changed the diseased gut bacteria population and/or lead to changes in the brain. AD mice showed an increase in neuronal activity and bacterial byproducts.
- The results suggest that bacterial imbalance, or dysbiosis, exists in Alzheimer's disease, and demonstrate that dysbiosis correlates with changes in SCFA levels in the brain.
Probiotic Therapeutics Prevent Neurological and Cognitive Deficits in Traumatic Brain Injury in Mice
Wellington Amaral, firstname.lastname@example.org, Abstract 541.12
- TBI is associated with various gastro-intestinal disorders, suggesting a connection between the gut microbiota and TBI. However, the exact relationship is unknown.
- Researchers investigated the ability of a probiotic treatment to protect brain function after TBI. TBI mice treated with a probiotic treatment no longer exhibited memory deficits. Furthermore, TBI mice without the treatment had a significantly less diverse gut microbiome.
- Current research focuses on the exact transmission between microbiota and the brain, and how manipulation of that relationship might help with TBI recovery.
Soluble TNF Mediates Obesogenic Diet-Induced Alterations in Peripheral and Brain Immunophenotype in a Mouse Model of Alzheimer's Disease
Malu Tansey, mgtansey@UFL.edu, Abstract 564.10
- Researchers studied anti-inflammatory mechanisms in the gut and their connection to AD. Tumor necrosis factor (TNF), which is elevated in AD patients, is a cell signaling protein, or cytokine, that regulates gut barrier and blood-brain barrier permeability and inflammation.
- Researchers hypothesized that soluble TNF (sTNF) is a key contributor to AD pathology and metabolic dysfunction. Since the immune system is negatively impacted by a high-fat/high-carbohydrate diet, they used AD mice fed a high-fat diet to assess whether diet-induced obesity alters immune cell population.
- Mice fed a poor diet and with inhibited sTNF signaling had more amyloid beta and more T cells in their brain. This suggests that diet impacts immune cell population via sTNF and may enhance neuroinflammation and neurodegeneration in AD.
About the Society for Neuroscience
The Society for Neuroscience is the world's largest organization of scientists and physicians devoted to understanding the brain and nervous system. The nonprofit organization, founded in 1969, now has nearly 37,000 members in more than 90 countries and over 130 chapters worldwide.