Impact of 16S rRNA on Intestinal Flora Alterations and Early Diagnosis in Early Alzheimer's Disease Patients.

Background: Alzheimer's Disease (AD), a complex clinical condition, relies on neuropsychological assessments for early diagnosis. Recently, the gut-brain axis has been recognized as crucial in AD development, with dysbiosis in gut microbiota implicated in disease progression. Utilizing 16S rRNA analysis provides comprehensive monitoring of gut microbiota, potentially revealing biological markers for Early Alzheimer's Disease (EAD). Therefore, this study aimed to investigate the diagnostic impact of 16S ribosomal RNA (rRNA) on changes in intestinal flora among EAD patients.

Methods: This study analyzed stool samples from 50 AD patients and 50 healthy controls between June 2022 and June 2023. Based on the disease stage, patients were categorized into EAD (n = 14) and Late Alzheimer's Disease (LAD) groups (n = 36). The V3-V4 region was sequenced using 16S rRNA quantitative Polymerase Chain Reaction (qPCR) to compare the composition of gut microbiota and differences in abundance among the three experimental groups.

Results: The abundance and diversity of gut microbiota significantly increased in EAD patients compared to the healthy control group. Furthermore, 39 genera showed considerable variations between EAD and LAD patients and healthy controls, with notable increases in the abundance of Bryantella, Gemmiger, Desulfovibrio, Collinsella, and Odoribacter among EAD patients. Additionally, significant differences were observed across the Desulfovibrioales and Verrucomicrobiales, which could help distinguish EAD patients (Area Under the Curve (AUC) range 0.854, 0.966, p < 0.05).

Conclusion: 16S rRNA technology can be used to identify EAD patients, with the Desulfovibrioales and Verrucomicrobiales indicators serving as potential biological markers.