New study reveals altered gut bacteria as potential biomarker for preclinical Alzheimer’s disease

Medscape reports that a recent study has discovered notable differences in the composition of gut bacteria between individuals with preclinical Alzheimer’s disease (AD) and those without the condition. These findings have significant implications, as they could pave the way for utilising gut microbiome analysis to identify individuals at a higher risk of developing dementia. Moreover, researchers are optimistic that interventions aimed at modifying the gut microbiome could potentially serve as preventive treatments to help delay cognitive decline in susceptible individuals.

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Lead investigator Gautam Dantas, PhD, acknowledged that it remains uncertain whether the gut influences the brain or vice versa but emphasised the importance of this association. He noted that the changes observed in the gut microbiome may simply be indicative of pathological changes in the brain. Alternatively, it is plausible that the gut microbiome actively contributes to the development of Alzheimer’s disease. In the latter case, interventions such as probiotics or faecal transfers could alter the gut microbiome and the disease’s trajectory.

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Published in Science Translational Medicine on 14 June, the study explores the role of gut microbes in Alzheimer’s disease pathogenesis, particularly during the preclinical phase. By examining 164 cognitively normal adults, including 49 individuals with biomarker evidence of preclinical AD, the researchers identified distinct profiles of gut microbial taxonomy in those with preclinical AD compared to their healthy counterparts. The observed changes in the gut microbiome were found to occur early in the disease process, as they correlated with amyloid and tau biomarkers but not neurodegeneration biomarkers.

Furthermore, the study identified specific microbial taxa associated with preclinical AD, and incorporating these features improved the accuracy, sensitivity, and specificity of machine learning classifiers for predicting preclinical AD status. These findings suggest stool-based markers could complement early preclinical AD screening measures. The simplicity and ease of using the gut microbiome as a screening tool were highlighted by Beau Ances, MD, PhD, a professor of neurology at Washington University in St. Louis.

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Overall, the study provides valuable insights into the potential of analysing the gut microbiome as a biomarker for preclinical Alzheimer’s disease. While further research is necessary to unravel the exact nature of the gut-brain relationship, these findings open up new possibilities for early detection and targeted interventions in the fight against Alzheimer’s.

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