PROJECT ABSTRACT: Among people with HIV infection (PWH), hazardous drinking is a common, modifiable risk factor for cardiovascular disease (CVD) and death. Both alcohol and HIV cause gut dysbiosis. Gut dysbiosis is associated with systemic inflammation and harmful metabolites, each of which is associated with CVD and death. However, the specific bacterial shifts that drive dysbiosis and its harmful effects among PWH who drink are unclear. Our overarching model posits that alcohol associated gut dysbiosis leads to a reduction in specific species of butyrate-producing bacteria, lowering butyrate levels and increasing trimethylamine N-oxide (TMAO). These mechanisms contribute to microbial translocation and vascular inflammation. Ultimately, these processes promote CVD and excess mortality. This application leverages rich existing data from three fully harmonized NIAAA cohort studies (ACME HIV, U01AA026222; TMAO HIV, R01AA025859; META HIV, P01AA029542) in response to NOT-AA-23-011 requesting proposals for use of existing data and biospecimens in alcohol research. We hypothesize that alcohol associated gut dysbiosis will be characterized by reductions in butyrate-producing species (Aim 1); that reductions in these species will associate with increased levels of microbial translocation, inflammation, and harmful metabolites (Aim 2); and that reductions in butyrate-producing species will associate with greater subclinical CVD dysfunction, CVD risk, and mortality risk (Aim 3). Prior studies examining alcohol associated dysbiosis in PWH are limited in two major ways: (1) they rely on 16S characterization of the gut microbiome, which cannot provide granular (i.e., species level) data; or (2) they employ whole genome sequencing (WGS) to collect species level data, but only in small samples. Our application is innovative because it addresses both limitations by utilizing WGS in three existing, fully harmonized NIAAA-funded studies involving 583 PWH who consume alcohol with >1700 longitudinal fecal specimens. Extant data include alcohol measures (AUDIT; Timeline Followback, TLFB; phosphatidyl ethanol, PEth), stored serum/plasma and fecal samples, 16S gut microbiome data, and serum biomarkers for metabolites (e.g., TMAO), microbial translocation (e.g., LBP), inflammation (e.g., IL-6), VACS Index (mortality) and Reynolds Risk (CVD) scores, and echocardiograms. New data to be generated are WGS on all fecal samples from the three studies. Specific Aims are as follows: Aim 1: To characterize alcohol associated dysbiosis using WGS, employing longitudinal fecal specimens. Aim 2: To test the relations of the gut microbiome at species/strain-level with markers of microbial translocation, inflammation, and harmful metabolites. Aim 3: To test the association of species/strain-level changes in butyrate-producing and other gut bacteria with subclinical CVD markers, CVD risk, and mortality risk. IMPACT: Precision medicine approaches utilizing gut microbiota profiles at the...