Memory loss has various causes, however, some attribute the frequency to age. But, after the first symptoms appeared in a 19-year-old young man, everything seemed to indicate that the memory loss went further. Due to the situation, although scientists were already investigating the cause and how to counteract the effects or symptoms, it was now vitally important to know what caused it.
About 20 years before the first symptoms of Alzheimer’s disease begin, toxic proteins that are responsible for its appearance begin to be deposited in the brain. Although Alzheimer’s is an age-dependent disease in which memory loss is very common, determining its origin was complicated; it was recently discovered that intestinal microbes play a key role.
Beyond memory loss, it is also present in young people
Scientists have discovered that transplanting gut microbes from people with Alzheimer’s disease into healthy rats causes the animals to develop symptoms of the disease. The result could pave the way for new treatments and confirms what many have long argued: that the gut microbiome plays a key role in Alzheimer’s. The study was the result of an international collaboration and was led by Professor Yvonne Nolan from the APC Microbiome Ireland research center based at University College Cork.
“People with Alzheimer’s are usually diagnosed at or after the onset of cognitive symptoms, which may be too late, at least for current therapeutic approaches. Understanding the role of gut microbes during prodromal (or early-stage) dementia, before the possible onset of symptoms, may open avenues for the development of new therapies, or even individualized intervention,” Nolan explained in a statement.
The team recruited 69 Alzheimer’s disease patients and 64 control subjects and collected blood and stool samples from them. The stool samples were prepared for a procedure called fecal microbiota transplantation (FMT), which is exactly what it sounds like. The lucky ones in this case were a group of young adult male rats, selected to eliminate any effects of natural aging.
Once the rats were pretreated with antibiotics to deplete their microbiota, FMT was performed. Ten days later, the rats began a program of behavioral testing. Subsequently, samples of their intestinal tissues, brain tissues, blood, and feces were also collected for analysis. The result was clear. Human patients were found to have higher levels of inflammation-promoting bacteria in their fecal samples, which correlated with their degree of cognitive impairment or memory loss. Transferring these gut microbes to the rats caused them to develop symptoms associated with dementia.
“The memory tests we investigate are based on the growth of new nerve cells in the hippocampal region of the brain. We saw that animals with gut bacteria from people with Alzheimer’s produced fewer new nerve cells and had memory problems, leading to memory loss,” Nolan said.
This story was written in Spanish by Perla Vallejo in Ecoosfera
