EXPRESS: Remote ischemic peconditioning and postconditioning reduced cerebral ischemic injury modulating inflammatory responses and metabolic pathways

Remote ischemic conditioning (RIC) mitigates ischemic injury through transient, repetitive vascular occlusion in a limb distant from the injury site. Although its protective effects are recognized, the underlying mechanisms remain incompletely understood. This study investigated the metabolic and inflammatory changes induced by RIC to identify novel cytoprotective targets.We used a mouse model of transient focal cerebral ischemia induced by 60-minute occlusion of the distal middle cerebral artery. Two RIC protocols were applied: RIPerC (remote ischemic perconditioning), consisting of three cycles of 5-minute hindlimb ischemia followed by 5-minute reperfusion during ischemia, and RIPostC (remote ischemic postconditioning), applied after reperfusion. Plasma cytokines were quantified using a multiplex assay, and metabolomic profiles of plasma and brain samples were analyzed by untargeted liquid chromatography-mass spectrometry (LC-MS). Data were evaluated with univariate and multivariate statistical methods.RIC induced moderate changes in the brain metabolome but significantly increased three plasma metabolites: Cer(42:3), HexCer(36:1), and TG(28:0), suggesting systemic metabolic modulation during ischemia-reperfusion. Both RIPerC and RIPostC conferred neuroprotection, likely through regulation of peripheral immune responses.These findings demonstrate that RIPerC and RIPostC protect against ischemic injury by modulating inflammatory and metabolic pathways in systemic circulation and brain, providing insights into ischemic tolerance and biomarker discovery.