J. Exp. Med: antibiotic treatment can reduce Alzheimer's symptoms in male mice

May 18, 2019 / Biovalley / University of Chicago researchers have shown that the type of bacteria living in the gut can affect the development of Alzheimer's symptoms in mice The study, published in the Journal of experimental medicine on May 16, shows that long-term antibiotic treatment can reduce inflammation by changing intestinal microflora, thus slowing down the growth of amyloid plaques in the brain of male mice, but the same treatment has no effect on female mice The bacterial communities that live in the gastrointestinal tract, the gut microbiota, are generally harmless, but because they affect the activity of the human immune system, these bacteria can affect a wide range of diseases, even distant tissues, such as the brain Source: Professor sangram s sisodia, director of the center for molecular neurobiology at the University of Chicago, J exp Med, explained: "recent evidence suggests that gut bacteria may play an important role in a variety of neurological diseases, including autism, multiple sclerosis, Parkinson's disease and Alzheimer's disease "Alzheimer's disease is characterized by the formation of amyloid plaques and the activation of microglia, the immune cells present in the brain These cells can help clear amyloid plaques, but their activation may also aggravate the disease by causing neuritis The gut microbiome of Alzheimer's patients has changed, and sisodia and his colleagues have previously reported that gut bacteria may affect the development of these symptoms in rodents Long term antibiotic treatment limited the formation of amyloid plaques and reduced microglial activation in male (rather than female) mice expressing mutant proteins associated with familial Alzheimer's disease "While compelling, our published study of the role of intestinal microbiota in amyloid plaque formation is limited to one mouse "Sisodia said In this new study, sisodia and his colleagues studied the effect of antibiotics on app s1-21, another Alzheimer's mouse model The long-term use of mixed antibiotics again reduced the amyloid plaques in male mice, but had no effect on female mice Antibiotic treatment also appears to have altered the activation of microglia in male mice, transforming them from a form believed to promote neurodegeneration to a form that helps maintain a healthy brain To prove that the improvement in Alzheimer's symptoms is caused by changes in the intestinal microbiota, the researchers transplanted untreated rat feces into antibiotic treated animals This process restored the intestinal microflora and led to the formation of amyloid plaques and the increase of microglia activation But why do changes in gut microbiome affect only male mice? Sisodia and his colleagues found that long-term antibiotic treatment changed intestinal bacteria in male and female mice in different ways The change of microbiome in female mice results in the production of several kinds of proinflammatory factors which may affect the activation of microglia "Our study shows that antibiotic mediated intestinal microbiome interference has selective and gender specific effects on the formation of amyloid plaques and microglia activity in the brain," sisodia said "We now want to see if these results can be attributed to changes in any particular type of bacteria (BIOON Com) reference: dodiya et al Sex specific effects of microorganisms on cerebellal a β aminoidosis and microglia phenotype s, J exp Med 2019 Doi: 10.1084/jem.20182386