Mitochondrial Immunometabolism in Sepsis: From Oxidative Stress and mtDAMP Signaling to Biomarker-Guided Therapy

Sepsis is a life-threatening syndrome characterized by a dysregulated host response to infection and progressive organ dysfunction. Although early antimicrobial therapy, source control, hemodynamic resuscitation, and organ support remain the foundations of care, these approaches do not directly reverse the cellular mechanisms that connect systemic inflammation to multi-organ failure. Mitochondrial dysfunction has emerged as a central mechanism linking impaired oxygen utilization, oxidative and nitrosative stress, immune-cell metabolic reprogramming, inflammatory amplification, and organ injury. During sepsis, inflammatory mediators, nitric oxide, microcirculatory abnormalities, calcium dysregulation, and metabolic stress converge on mitochondria, impairing oxidative phosphorylation and promoting mitochondrial reactive oxygen species/reactive nitrogen species (ROS/RNS) generation. When mitochondrial quality-control programs, including fission, fusion, mitophagy, and mitochondrial biogenesis, fail to restore network integrity, damaged mitochondria accumulate and become persistent sources of oxidative stress and danger signals. Mitochondrial damage-associated molecular patterns, particularly mitochondrial DNA, oxidized mitochondrial DNA, cardiolipin, ATP, and N-formyl peptides, activate innate immune pathways such as TLR9-MyD88-NF-kappaB, the NLRP3 inflammasome, and cGAS-STING signaling. In parallel, mitochondrial metabolism shapes macrophage activation, neutrophil function, T-cell competence, pyruvate-lactate handling through the pyruvate dehydrogenase complex, and the transition between hyperinflammation and immunosuppression. Clinical translation remains challenging because sepsis is biologically heterogeneous and mitochondrial dysfunction is dynamic, tissue-specific, and influenced by disease stage. This review synthesizes current knowledge on mitochondrial dysfunction in sepsis, emphasizing oxidative and nitrosative stress, mitochondrial quality control, mitochondrial damage-associated molecular pattern (DAMP) signaling, immunometabolism, organ-specific injury, candidate biomarkers, clinical translational strategies for mitochondria-targeted therapy, and future approaches based on multi-omics and artificial intelligence-assisted patient stratification. We argue that future therapeutic development should move beyond nonspecific antioxidant supplementation toward time-sensitive, phenotype-informed, and biomarker-guided mitochondrial medicine.