Gut microbiome alterations in Alzheimer’s patients from Kazakhstan

AbstractBackgroundRecent studies strongly suggest that gut microbiome is capable of influencing brain functions and contribute to the development of Alzheimer’s disease (AD). However, only few studies have characterized the human gut microbiome communities associated with AD. Moreover, reported changes in the gut microbiomes in AD patients from different countries are not similar. Therefore, more research is needed in order to reveal the relationships existing between human microbiomes and AD in different ethnic populations. Here, we report the first pilot case‐control study of diversity and composition of gut microbiomes isolated from the patients diagnosed with AD in comparison with healthy seniors from the Central Asian region.MethodMicrobial DNA was isolated from fecal samples of the patients with confirmed AD (n=11) and healthy age‐ and gender‐matched individuals (n=13). The composition of gut microbiomes were characterized by 16S ribosomal RNA MiSeq sequencing. Data analysis was performed using less operational taxonomic units scripts (LotuS) and R (v4.03).ResultOur results demonstrated that gut microbiota of AD individuals had overall higher α‐diversity compared to healthy controls, although this difference was not significant. The absence of statistical power might be explained by a low sample size. However, we have found significant differences of bacterial abundance at class, order and genus levels. At class level the amount of Bacilli was depleted in AD group; at order level, the relative abundance of Oscillospirales increased, while the abundance of Lactobacillales decreased in AD patients. Among bacterial genera, microbiomes of AD participants were characterized by a preponderance of unknown_Prevotellaceae and unknown_Ruminococcaceae. Linear discriminant analysis (LDA) has revealed that the relative abundances of Eubacterium coprostanoligenes group, Rikenellaceae RC9 gut group, Bacilli RF39, Oscillospirales UCG‐011 were significantly different in AD patients compared to healthy participants.ConclusionStudying the gut microbiome alterations in AD patients is of considerable interest. By focusing on the mechanism of interactions between human microbiota and the brain, we can uncover new pathophysiological pathways leading to the onset and progression of AD, evaluate the contributions of environment and lifestyle to the increase in prevalence of dementia and develop practical recommendations for the prevention and treatment of this severe pathology.