Media release

From: AAAS

Large clinical study connects the gut microbiome with a risk of preclinical Alzheimer’s disease

The composition of the gut microbiome and the presence of certain bacterial species may correlate with early markers of preclinical Alzheimer’s disease, according to a longitudinal clinical study involving 164 people. The findings add to a growing body of evidence implicating the importance of the gut microbiome in the early stages of Alzheimer’s disease, and may help researchers develop more accurate models to predict the risk of the disorder. The human gut microbiome is a vast and extremely diverse community of organisms that is essential to health, metabolism, and well-being. Disruptions to the microbiome have now been linked to a plethora of disorders, and some research suggests that gut dysbiosis may even contribute to the development of neurodegenerative conditions. However, more research is needed to flesh out the connection between the gut microbiome and specific markers of Alzheimer’s disease. Aura Ferreiro and colleagues examined a cohort of 164 cognitively normal people with and without preclinical Alzheimer’s disease – defined as the asymptomatic presence of abnormal amyloid and tau proteins in the brain. Interestingly, the scientists found that people with preclinical Alzheimer’s disease had a different microbiome composition, such as a higher quantity of the bacterial species Dorea formicigenerans, as well as more active microbial pathways involved in the degradation of the amino acids arginine and ornithine. Ferreiro et al. then integrated these microbiome features to improve the accuracy and sensitivity of machine learning tests that predict preclinical Alzheimer’s disease, which they validated in 65 of the 164 study participants. “Microbiome markers in stool might complement early screening measures for preclinical [Alzheimer’s disease],” Ferreiro et al. say, adding that their work also raises the possibility of targeting gut-directed interventions to at-risk groups.