Effects of Bacterial-Derived Extracellular Vesicles in Rodent Models of Obesity, Metabolic Dysfunction-Associated Steatotic Liver Disease and Insulin Resistance/type 2 Diabetes. A Systematic Review

Obesity, metabolic-associated steatotic liver disease (MASLD) and insulin resistance/type II diabetes (IR/T2D) share gut microbiota dysbiosis as an etiological factor. Bacteria-derived extracellular vesicles (EVs) have emerged as a promising strategy to modulate gut microbiota composition. To systematically review preclinical in vivo evidence on the effects of bacterial-derived EVs in obesity, MASLD and IR/T2D in rats and mice. Following PRISMA guidelines (PROSPERO registration CRD420261293767), a systematic search was conducted in PubMed/Medline, Web of Science, Scopus and EMBASE® from inception until January 2026 for controlled in vivo studies in mice and rats. Nine studies met inclusion criteria, all of which were conducted in dietary mice models; no eligible rat studies, or genetically-induced models were identified. EVs administration generally reduced body and adipose tissue weight, hepatic lipid accumulation, improved glycaemic control, and modulated gut microbiota composition. Bacterial EVs show promise for preventing and treating obesity-related metabolic disorders, although evidence remains limited and heterogeneous.