A Longitudinal Study to Explore the Impact of Gut Microbiome on Brain Health in Alzheimer's Disease: China Healthy Brain and Gut Microbiome Study (CHBGMS)
Gut microbiota dysfunction is associated with Alzheimer's disease (AD). However, the potential modulatory mechanism remains unclear. Previous studies have shown that gut-derived metabolites short-chain fatty acids (SCFAs) may be the key mediators between gut microbiota and brain, participating in the modulatory pathway gut microbiota-SCFAs-brain networks. In this project, high-throughput targeted metabolomics technique will be used to explore the differences of SCFAs in the spectrum of AD, including cognitively normal individuals, subjective cognitive decline (SCD), mild cognitive impairment (MCI), and AD dementia. Then, the gut microbiome and multi-modal MRI techniques will be combined to elucidate potential interaction mechanisms of gut microbiota-SCFAs-brain networks. Finally, based on multi-omics features extracted from gut microbiome, metabolomics, and neuroimaging after five years, the diagnostic model of SCD due to preclinical AD will be established using machine learning methods.
• Cognitively normal group:
‣ normal performance on standardized cognitive tests;
⁃ with no cognitive complaints or any concerns (worries).
• SCD group:
‣ self-experienced persistent decline in memory, rather than other domains of cognition;
⁃ normal performance on standardized cognitive tests;
⁃ failure to meet the criteria for MCI or dementia;
⁃ age at onset of SCD ≥ 60 years old;
⁃ onset of SCD within the last 5 years;
⁃ concerns (worries) associated with SCD;
⁃ feeling of worse performance than others of the same age group.
• MCI group:
‣ having impaired scores on both measures in at least one cognitive domain (memory, language, or speed/executive function);
⁃ having impaired scores in each of the three cognitive domains (memory, language, or speed/executive function);
⁃ the Functional Activities Questionnaire (FAQ)≥9.
• AD dementia group:
‣ meet the criteria for dementia and have impaired daily functional activities;
⁃ episodic memory deficit; 3) Clinical Dementia Rating (CDR) ≥ 1.