Whole-body volatile organic compound profiling reveals metabolic pathway perturbations in a murine polymicrobial sepsis model: a feasibility study

Sepsis rewires host metabolism, and these changes may be readable in the volatile organic compounds (VOCs) released from the body. Whether whole-body VOC profiles can be mapped onto specific disrupted biochemical pathways has not been tested. In this discovery-phase, single-time-point feasibility study, polymicrobial sepsis was induced by cecal ligation and puncture (CLP) in C57BL/6 mice (14 CLP, 10 sham controls). Whole-body headspace gases were collected 12 h after surgery and analysed by thermal desorption-gas chromatography-mass spectrometry. After preprocessing, 113 features were tested univariately with Benjamini-Hochberg correction and by orthogonal partial least squares discriminant analysis (OPLS-DA). Candidate VOCs (FDR < 0.1, |log2FC| > 0.26, VIP > 1.0) were annotated against PubChem, KEGG COMPOUND, and the Human Metabolome Database. OPLS-DA separated the groups (R2X = 0.489, R2Y = 0.981, Q2 = 0.777; P = 0.001 by 1,000 permutations), and leave-one-out cross-validation classified 95.8% of animals correctly, though n = 24. Of 54 candidate VOCs, 18 had established endogenous origins; 16 fell and 2 rose in septic mice. Pathway mapping indicated four perturbed domains: lipid peroxidation (12 depleted VOCs), ketone body metabolism (3 decreased), cholesterol/isoprenoid metabolism (isoprene, decreased), and putative gut microbiota-associated metabolism (toluene and carbon disulfide, increased). All 18 endogenous VOCs kept candidate status after environment-derived VOCs were removed. Because whole-body headspace volatiles superimpose tissue metabolism, ventilation, activity, and background, these results suggest the septic volatilome may be mapped onto distinct pathway perturbations; ventilation and activity effects cannot be excluded. These findings generate testable hypotheses for non-invasive metabolic phenotyping in sepsis.