Fecal microbiota transplantation from patients into animals to establish human microbiota-associated animal models: a scoping review

Abstract

Abstract Background Fecal microbiota transplantation (FMT) from humans with specific medical conditions to animal models can demonstrate causality by inducing or exacerbating pathophenotypes, linking the gut microbiota to health outcomes. Methods We conducted a scoping review searching MEDLINE, EMBASE, Scopus, and Web of Science through July 2024 to identify human noninfectious diseases studied using FMT in animal models, investigate FMT methodologies, and assess the feasibility of systematic reviews on the role of the microbiota in specific diseases. Results From 605 reports of 489 studies, we found that inflammatory bowel diseases, irritable bowel syndrome, obesity, colorectal cancer, and depression were the most commonly studied, with cancer research focusing on immunotherapy non-responsiveness. In a random sample of studies, gastrointestinal outcomes were most frequently reported, with remarkably high rates (> 80%) of successful induction of disease-specific alterations for intestinal barrier function, gastrointestinal inflammation, circulating immune parameters, and fecal metabolites. Most studies used C57BL/6 mice and oral gavage administration, with recipients being either germ-free or antibiotic-pretreated. We created tables linking conditions with publications to facilitate future systematic reviews. Conclusions Although human-to-animal FMT studies cover diverse conditions, methodological heterogeneity and inconsistent reporting hinder comparability. Standardized protocols and guidelines are needed. For several conditions, sufficient literature exists to assess the role of the gut microbiota in human health through systematic reviews.

Keywords

• Fecal microbiota transplantation
• Animal model
• Dysbiosis
• Causality
• Etiology
• Research design