AUTHOR=Muthumula Chandra Mohan Reddy , Yanamadala Yaswanthi , Gokulan Kuppan , Karn Kumari , Cunny Helen , Sutherland Vicki , Santos Janine H. , Khare Sangeeta TITLE=Effect of in utero and lactational exposure to antiretroviral therapy on the gut microbial composition and metabolic function in aged rat offspring JOURNAL=Experimental Biology and Medicine VOLUME=Volume 250 - 2025 YEAR=2025 URL=https://www.ebm-journal.org/journals/experimental-biology-and-medicine/articles/10.3389/ebm.2025.10468 DOI=10.3389/ebm.2025.10468 ISSN=1535-3699 ABSTRACT=Despite the highly effective impact of antiretroviral therapy (ART) in reducing mother-to-child transmission of human immunodeficiency virus (HIV), there are concerns of long-term impacts of ART on the health of the offspring. The implications of perinatal exposure to antiviral drugs on the gut bacterial population and metabolic function in the offspring is unclear but may influence health outcomes given the various reported effects of the microbiome in human health. This study aims to gain insight into the potential effect of in utero and lactational exposure to ART on gut microbiota populations and short‐chain fatty acids (SCFAs) production in aged rat offspring. Pregnant rats were administered a combination of antiretroviral drugs (abacavir/dolutegravir/lamivudine) at two different dose levels during gestation and throughout lactation, and the fecal bacterial abundance and SCFA levels of the offspring were analyzed when they reached 12 months of age. Our results showed dose-dependent and sex-based differences in fecal microbial abundance at various taxonomic levels. Specifically, we found a decline in Firmicutes in males, and an increase in Actinobacteria among males and females. Furthermore, a sex-specific distribution reorganization of Lactobacillus, Bifidobacterium, and Akkermansia was identified. No significant difference in the concentration of prominent SCFAs and IgA levels were identified. These findings provide preliminary information indicating the need to evaluate perinatal effects of ART more comprehensively on the gut bacterial and metabolic function in future studies, and their potential role in offspring health outcomes.