Specialized pro-resolving mediators in obesity and overweight conditions: A systematic review of human and animal evidence on comparative differences and associations.
Obesity and overweight are characterized by persistent low-grade inflammation. Specialized pro-resolving mediators (SPMs), polyunsaturated fatty acid-derived metabolites, actively promote inflammatory resolution, and their dysregulation has been linked to unresolved inflammation and metabolic disturbances in obesity. This systematic review synthesized human and animal evidence on adiposity-related differences and associations in SPMs and SPM precursors. The protocol was prospectively registered in PROSPERO (CRD420251067464). PubMed/MEDLINE, Scopus, Web of Science, and Embase were searched up to 22 May 2026. Eligible studies included human and animal research comparing SPMs and/or SPM precursors between overweight/obese and normal-weight/lean groups or assessing their associations with adiposity indices. Due to heterogeneity across matrices and analytical platforms, findings were synthesized narratively. Twenty-seven unique studies were included, providing 28 experimental datasets (14 animal and 14 human). The most consistent alterations were observed in adipose tissue and circulation, where overweight/obesity was frequently associated with lower concentrations of SPMs and/or SPM precursors. In humans, circulating Resolvin E1 showed reproducible reductions and was inversely associated with adiposity measures in several cohorts. In contrast, selected metabolites, including SPM Lipoxin A4 and the SPM precursors 15-HETE and 18-HEPE, exhibited mixed directionality across studies. Evidence for hepatic and central nervous system compartments was limited and heterogeneous. Overall, available evidence suggests that excess adiposity is associated with altered SPM and precursor profiles, most consistently in adipose tissue and circulation, whereas hepatic and central nervous system findings remain inconsistent. Future studies using standardized quantification and tissue-specific designs are needed to clarify whether targeting pro-resolving pathways has translational potential in obesity-related metabolic dysfunction.