Depression in HIV and HCV Co-Infected Individuals is Associated with Systematic Differences in the Gut Microbiome and Metabolome. Neurogerm core

Depression is influenced by the structure, diversity, and composition of the gut microbiome. Although depression has been described previously in human immunodeficiency virus (HIV) and hepatitis C (HCV) mono-infections, and to a lesser extent HIV-HCV coinfection, research on the interplay between depression and the gut microbiome in these disease states is limited. Here, we characterized the gut microbiome using 16S rRNA amplicon sequencing of fecal samples from 373 participants who underwent a comprehensive neuropsychiatric assessment, and the gut metabolome on a subset of these participants using untargeted metabolomics with liquid chromatography mass spectrometry. We observed that the gut microbiome and metabolome were distinct between HIV positive and negative individuals. HCV infection had a large association with the microbiome that was not confounded by drug use. Therefore, we classified the participants by HIV and HCV infection status (HIV-monoinfected, HIV-HCV coinfected, or uninfected). The three groups significantly differed in their gut microbiome (unweighted UniFrac distances) and metabolome (Bray Curtis distances). Coinfected individuals also had lower alpha diversity. Within each of the three groups, we evaluated lifetime Major Depressive Disorder (MDD) and current Beck Depression Inventory II. We found that the gut microbiome differed between depression states only in coinfected individuals. Coinfected individuals with a lifetime history of MDD were enriched in primary and secondary bile acids, as well as taxa previously identified in people with MDD. Collectively, we observe persistent signatures associated with depression only in coinfected individuals, suggesting that HCV itself, or interactions between HCV and HIV, may drive HIV-related neuropsychiatric differences.