Park Youngchan, Lee Jong-Young, Lee Eek-Sung
Division of Bio Bigdata, Department of Precision Medicine, Korea National Institution of Health, Korea Disease Control and Prevention Agency, Cheongju, Republic of Korea.
OneOmics Co., Ltd., Bucheon, Republic of Korea.
Osong Public Health Res Perspect. 2025 Apr;16(2):141-151. doi: 10.24171/j.phrp.2024.0329. Epub 2025 Mar 24.
This study aimed to investigate the relationship between blood microbiota, specifically bacterial DNA, and cognitive decline in individuals with subjective cognitive decline (SCD) and amnestic mild cognitive impairment (aMCI). The objective was to identify potential microbial signatures that could serve as biomarkers for cognitive deterioration.
Forty-seven participants were recruited, including 13 with aMCI, 20 with SCD, and 14 normal cognition (NC). Blood samples were collected, and microbial DNA was analyzed using 16S rRNA sequencing on the Illumina MiSeq platform. Bioinformatics analyses-including α- and β-diversity measures and differential abundance testing (using edgeR)-were employed to assess microbial diversity and differences in bacterial composition among groups. Logistic regression models were used to evaluate the predictive impact of the microbiota on cognitive decline.
Microbial diversity differed significantly between groups, with NC exhibiting the highest α-diversity. Both the aMCI and SCD groups showed reduced diversity. Taxa such as Bacteroidia, Alphaproteobacteria, and Clostridia were significantly decreased in the aMCI group compared to NC (p< 0.05). In contrast, Gammaproteobacteria increased significantly in the aMCI group compared to both NC and SCD, indicating progressive microbial changes from SCD to aMCI. No significant differences were found between the NC and SCD groups.
Distinct bacterial taxa-particularly the increase in Gammaproteobacteria along with decreases in Bacteroidia, Alphaproteobacteria, and Clostridia-are associated with the progression of cognitive decline. These findings suggest that blood microbiota could serve as potential biomarkers for the early detection of aMCI. However, the small sample size and the lack of control for confounding factors such as diet and medication limit the findings. Larger studies are needed to validate these results and further explore the role of microbiota in neurodegeneration.
本研究旨在调查血液微生物群，特别是细菌DNA，与主观认知下降（SCD）和遗忘型轻度认知障碍（aMCI）个体认知衰退之间的关系。目的是识别可作为认知衰退生物标志物的潜在微生物特征。
招募了47名参与者，包括13名aMCI患者、20名SCD患者和14名认知正常（NC）者。采集血样，并在Illumina MiSeq平台上使用16S rRNA测序分析微生物DNA。采用生物信息学分析，包括α和β多样性测量以及差异丰度测试（使用edgeR），以评估微生物多样性和各组细菌组成的差异。使用逻辑回归模型评估微生物群对认知衰退的预测影响。
各组之间的微生物多样性存在显著差异，NC组的α多样性最高。aMCI组和SCD组的多样性均降低。与NC组相比，aMCI组中的拟杆菌纲、α变形菌纲和梭菌纲等分类群显著减少（p<0.05）。相比之下，与NC组和SCD组相比，aMCI组中的γ变形菌纲显著增加，表明从SCD到aMCI存在渐进性微生物变化。NC组和SCD组之间未发现显著差异。
不同的细菌分类群，特别是γ变形菌纲的增加以及拟杆菌纲、α变形菌纲和梭菌纲的减少，与认知衰退的进展有关。这些发现表明，血液微生物群可作为早期检测aMCI的潜在生物标志物。然而，样本量小以及缺乏对饮食和药物等混杂因素的控制限制了研究结果。需要更大规模的研究来验证这些结果，并进一步探索微生物群在神经退行性变中的作用。
