Blood (POS) untargeted metabolomics raw data

Metabolomic analyses of blood samples from 50 Hunner-type IC/BPS patients and 30 healthy controls were performed at Shanghai Applied Protein Technology Co. Ltd. (Shanghai, China). 100 µL of supernatant was then mixed with 400 µL of ice-cold methanol/acetonitrile (1:1, v/v) to precipitate proteins, followed by vortexing and a second centrifugation at 15,000 × g for 15 min at 4 °C. The resulting supernatant was collected for LC-MS/MS analysis. Using a UHPLC system (1290 Infinity LC, Agilent Technologies) coupled with a quadrupole time-of-flight mass spectrometer (TripleTOF 6600, AB Sciex). Processed data were normalized and subjected to multivariate analysis, including Pareto-scaled principal component analysis (PCA) and orthogonal partial least-squares discriminant analysis (OPLS-DA). Variable importance in projection (VIP) score was calculated from the OPLS-DA model to evaluate each metabolite's contribution to group separation. Metabolites with VIP ≥ 1 and P < 0.05 were considered statistically significant. Functional prediction of differentially abundant metabolites was performed using the Kyoto Encyclopedia of Genes and Genomes (KEGG) database.