Warding off Alzheimer's disease could one day be as easy as popping antibiotics, suggests a new study.
In the University of Chicago study, long-term treatment with broad spectrum antibiotics decreased levels of amyloid plaques, a hallmark of Alzheimer's disease, and activated inflammatory microglial cells in the brains of mice.
The study also showed significant changes in the gut microbiome after antibiotic treatment, suggesting the composition and diversity of bacteria in the gut play an important role in regulating immune system activity that impacts progression of Alzheimer's disease.
"We're exploring very new territory in how the gut influences brain health," said senior author Sangram Sisodia, adding: "This is an area that people who work with neurodegenerative diseases are going to be increasingly interested in, because it could have an influence down the road on treatments."
Two of the key features of Alzheimer's disease are the development of amyloidosis, accumulation of amyloid-Beta (ABeta) peptides in the brain, and inflammation of the microglia, brain cells that perform immune system functions in the central nervous system. Buildup of ABeta into plaques plays a central role in the onset of Alzheimer's, while the severity of neuro-inflammation is believed to influence the rate of cognitive decline from the disease.
For this study, Sisodia and his team administered high doses of broad-spectrum antibiotics to mice over five to six months. At the end of this period, genetic analysis of gut bacteria from the antibiotic-treated mice showed that while the total mass of microbes present was roughly the same as in controls, the diversity of the community changed dramatically.
The antibiotic-treated mice also showed more than a two-fold decrease in ABeta plaques compared to controls, and a significant elevation in the inflammatory state of microglia in the brain. Levels of important signaling chemicals circulating in the blood were also elevated in the treated mice.
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Sisodia cautioned, "There's probably not going to be a cure for Alzheimer's disease for several generations, because we know there are changes occurring in the brain and central nervous system 15 to 20 years before clinical onset," adding: "We have to find ways to intervene when a patient starts showing clinical signs, and if we learn how changes in gut bacteria affect onset or progression, or how the molecules they produce interact with the nervous system, we could use that to create a new kind of personalized medicine."
The study is published in Scientific Reports.