The study has shown that a mixture of antibiotics had a beneficial effect on the gut bacteria of a group of mice to the point that it delayed the growth and development of Alzheimer’s , but only in male mice, not in females.
The study, conducted at the University of Chicago (USA), tested how long-term use of antibiotics could reduce inflammation and slow the growth of amyloid plaques in male mice.
Amyloid plaques
Amyloid plaques are a specific feature of Alzheimer’s disease. They are formed when a particular protein within neurons in the brain accumulates and clumps together. These amyloid plaques disrupt brain cell function and lead to Alzheimer’s symptoms.
The experts, led by Sangram S. Sisodia, already knew that people with Alzheimer’s show changes in their gut bacteria , and they had done previous studies showing how gut bacteria might affect Alzheimer’s-like symptoms in rodents.
This research found that changes in the microbiome limited the development of amyloid plaques in male mice, but not in females.
Studying antibiotics and Alzheimer’s
The researchers conducted a new study on a mouse model of Alzheimer’s disease, which scientists call APPPS1-21. They used a combination of antibiotics to see how it affected the formation of amyloid plaques and the activation of microglia in the brains of the rodents. Microglia are immune cells that can cause inflammation in the brain when activated.
The experts found that long-term antibiotic use affected the microbiome of male and female mice differently. They found that the antibiotics reduced the growth of amyloid plaques and changed the microglia to a shape that helps keep the brain healthy, but only in male mice.
For females, microbial changes in the gut affected their immune systems, increasing the production of factors that could increase the activation of microglia . This did not happen in male mice.
To confirm their findings, the researchers transplanted fecal material from male APPPS1-21 mice that had not received the antibiotics into those that had received long-term antibiotic treatment.
The team found that this reset the gut microbiome, which in turn, resulted in increased amyloid plaque formation and microglia activation.
Signs and symptoms of Alzheimer’s
Alzheimer’s disease is not part of the course of aging, although researchers note that increasing age is one of the most important risk factors for the development of the disease.
There is a possibility that genetics could also play a key role. Some research also suggests that Alzheimer’s disease may have connections to a variety of health and lifestyle factors, including obesity, heart disease, high blood pressure, and diabetes.
Alzheimer’s is a disease that progressively worsens over time. Most people who develop this disease experience memory problems early on, which can manifest themselves in many ways.
This type of memory loss can interfere with daily life. As the disease progresses, people with Alzheimer’s can easily repeat questions or get lost. They may also have trouble managing money and paying bills or have difficulty completing everyday tasks at home or at work. In addition, the disease can impair their judgment and some may experience changes in mood or behavior.
Do these results translate to human patients?
There is currently no cure for Alzheimer’s disease, but there are some treatments available to help patients manage symptoms and others that slow the progression of the disease. However, research is being done to find a cure or treatment that stops the disease from progressing.
This new study is promising, but scientists need to do more research to find out what benefit, if any, it could translate to humans.
“Our study shows that antibiotic-mediated disturbances of the gut microbiome have sex-specific influences on amyloid plaque formation and microglial activity in the brain. We now want to investigate whether these results can be attributed to changes in any particular type of bacteria.” explains Sangram S. Sisodia, in the Journal of Experimental Medicine that published the study.
Referencia: Sex-specific effects of microbiome perturbations on cerebral Aβ amyloidosis and microglia phenotypes. Hemraj B. Dodiya, Thomas Kuntz, Shabana M. Shaik, Caroline Baufeld, Jeffrey Leibowitz, Xulun Zhang, Neil Gottel, Xiaoqiong Zhang, Oleg Butovsky, Jack A. Gilbert, Sangram S. Sisodia. Journal of Experimental Medicine. DOI: 10.1084/jem.20182386 | Published 2019
