Butyrate administration is not sufficient to improve immune reconstitution in antiretroviral-treated SIV-infected macaques

Defective gastrointestinal barrier function and, in turn, microbial translocation have been identified as significant contributors to persistent inflammation in antiretroviral (ARV)-treated people living with HIV. Metabolic supplementation of short-chain fatty acids (SCFAs), generally produced by the commensal microbiome, may improve these outcomes. Butyrate is a SCFA that is essential for the development and maintenance of intestinal immunity and has a known role in supporting epithelial integrity. Herein we assessed whether supplementation with the dietary supplement sodium butyrate would improve immune reconstitution and reduce inflammation in ARV-treated, simian immunodeficiency virus (SIV)-infected rhesus macaques. We demonstrate that butyrate supplementation does not significantly improve immune reconstitution, with no differences observed in systemic CD4+ T-cell frequencies, T-cell functionality or immune activation, microbial translocation, or transcriptional regulation. Our findings demonstrate that oral administration of sodium butyrate is insufficient to reduce persistent inflammation and microbial translocation in ARV-treated, SIV-infected macaques, suggesting that this therapeutic may not reduce co-morbidities and co-mortalities in treated people living with HIV.