GFAP and Alzheimer disease: Meng et al. combined plasma proteomics, metabolomics, and gut and saliva metagenomics across clinically stratified AD groups and linked severity to coordinated changes that included NEFL and GFAP in plasma, amino-acid, and lipid shifts and microbiome features such as Paraprevotella clara; machine learning models predicted ADAS-Cog severity from integrated features [30].