Figure 4.
CSF metabolic profile analysis in REP and NEP. (A) Donut chart showing HMDB-based classification of all annotated metabolites. (B) PCA plot depicting metabolic variation between REP and NEP groups. (C) PLS-DA score plot illustrating distinct clustering of REP and NEP samples. (D) Validation of the PLS-DA classification model through permutation testing (n = 1000), with an empirical p-value of 0.044. (E) Important features with VIP > 1 identified by PLS-DA model. (F) Pathway analysis of metabolites with VIP > 1 in REP compared to NEP. CSF, cerebrospinal fluid; NEP, non-epilepsy; REP, refractory epilepsy; KEGG, Kyoto Encyclopedia of Genes and Genomes; HMDB, Human Metabolome Database; PCA, principal component analysis; PLS-DA, partial least-squares regression discriminant analysis; VIP, variable importance in projection.