Project Summary/Abstract Liver disease is a leading cause of mortality in persons with HIV (PWH), and PWH suffer a disproportionate burden of non-alcoholic fatty liver disease (NAFLD). While the mechanisms underlying this disparity are not well understood, intestinal dysbiosis and intestinal barrier dysfunction are implicated in the pathogenesis of NAFLD in HIV-negative persons. HIV infection has been shown to alter the intestinal microbiome, change the plasma metabolome and impair intestinal barrier function; however, there are few data on the microbiome and metabolome among PWH with NAFLD. My pilot preliminary data show that hepatic steatosis is associated with differences in the intestinal bacterial community (reduction in butyrate-producing bacteria), bacteria-related metabolites (including phosphatidylcholine), and markers of intestinal barrier dysfunction among PWH on long- term ART. I hypothesize that intestinal dysbiosis in PWH promotes NAFLD through 1) impairment of intestinal barrier function and 2) alteration of the plasma metabolome to promote hepatic lipid deposition. In Aim 1 I will determine whether differences in plasma levels of NAFLD- and bacteria-related metabolites, including phosphatidylcholine and trimethylamine N-oxide, are associated with hepatic steatosis in PWH. In Aim 2 I will determine whether decreased abundance of butyrate-producing gut bacteria and markers of impaired intestinal barrier function are associated with hepatic steatosis in PWH. In Aim 3 I will test the feasibility and limited efficacy of a multi-strain probiotic and prebiotic fiber on NAFLD biomarkers in a prospective trial in PWH. Aims 1 and 2 will leverage existing data and specimens from 134 PWH in the NIH-supported HIV, Adipose Tissue Immunology and Metabolism (HATIM) cohort, which includes metabolomic, microbiome, and imaging studies from participants with a spectrum of metabolic fitness and in the absence of viral hepatitis or excessive alcohol use. Secondary analyses will compare the findings from the HATIM cohort with both HIV-negative controls and PWH with viral hepatitis and heavy alcohol use. The Aim 3 pilot trial will leverage the well-developed infrastructure and large recruitment pool of the Tennessee Center for AIDS Research. Collectively, these Aims address the call for research related to HIV-associated comorbidities, coinfections and complications described in NIH Strategic Plan for HIV and HIV-related Research, and have the potential to inform new microbiome- based diagnostics and treatments that will reduce the burden of NAFLD in PWH. My research and training plan will be supported a multi-disciplinary team of scientists who have a strong record of mentoring young investigators and the world-class training environment and resources available at Vanderbilt University Medical Center. In addition to the benefits to the health of PWH, the proposed K23 studies and training plan will allow me to further my expertise in patient-facing resea...