Senescence-associated loss of intestinal α1,2-fucose disrupts a modifiable host-microbiome homeostasis axis in people with HIV.

Background: People with HIV (PWH), despite effective antiretroviral therapy (ART), experience disrupted intestinal homeostasis characterized by microbial dysbiosis and impaired intestinal barrier integrity, which contribute to chronic inflammation and aging-associated comorbidities. However, tractable mechanisms contributing to this dysfunction remain poorly defined. Objective: To determine whether acquired loss of intestinal α1,2-fucose, a host-derived intrinsic prebiotic glycan that supports colonization by short-chain fatty acid (SCFA)-producing bacteria essential for intestinal barrier integrity, contributes to microbiome disruption, impaired epithelial resilience, inflammation, and biological aging in PWH. Design: Ileal and colonic biopsies, isolated crypts, stool, and blood from PWH on ART and controls underwent multi-omic analyses. Findings were mechanistically interrogated using stool anaerobic fermentation assays and 3D intestinal organoid models of stress-mediated epithelial disruption. Results: In intestinal tissues, PWH exhibited reduced α1,2-fucosylation and increased senescence-associated expression of the fucose-degrading enzyme α-L-fucosidase. Lower α1,2-fucose tracked with depletion of SCFA-producing bacteria, increased inflammation, and premature biological aging. In anaerobic fermentations, stool from PWH produced fewer SCFAs than controls, whereas supplementation with the human-milk-oligosaccharide-derived α1,2-fucose donor 2'-fucosyllactose restored SCFA production and improved intestinal organoid resilience to stress-mediated disruption. Conclusion: These findings identify acquired loss of intestinal α1,2-fucose as a modifiable host-microbiome mechanism linking epithelial senescence, microbial metabolic dysfunction, impaired barrier resilience, inflammation, and biological aging in treated HIV infection.