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Researchers from Brigham and Women’s Hospital (BWH) have been using both animal models and human cells from patients to tease out the key players involved in the gut-brain connection as well as in the crosstalk between immune cells and brain cells. Their new publication defines a pathway that may help guide therapies for multiple sclerosis and other neurologic diseases.
These findings shows how the gut impacts central nervous system resident cells in the brain,” said corresponding author Francisco Quintana, Ph.D., of the Ann Romney Center for Neurologic Diseases at BWH. The new research focuses on the influence of gut microbes on two types of cells that play a major role in the central nervous system: microglia and astrocytes.
Microglia are an integral part of the body’s immune system, responsible for scavenging the CNS and getting rid of plaques, damaged cells and other materials that need to be cleared. But microglia can also secrete compounds that induce neurotoxic properties on the star-shaped brain cells known as astrocytes. This damage is thought to contribute to many neurologic diseases, including multiple sclerosis.
The byproducts that microbes produce when they break down dietary tryptophan-an amino acid found in turkey and other foods may limit inflammation in the brain through their influence on microglia. To conduct their study, the research team examined gut microbes and the influence of changes in diet in a mouse model of multiple sclerosis. They found that compounds resulting from the breakdown of tryptophan can cross the blood-brain barrier, activating an anti-inflammatory pathway that limits neurodegeneration.
The researchers also studied human multiple sclerosis brain samples, finding evidence of the same pathway and players. Activation of this same pathway has recently been linked to Alzheimer’s disease and glioblastoma.
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