Metabolomic Profiling Reveals Distinct Plasma Metabolic Signatures in Acne Patients with and without Depression
Si-Yu Chen1, Zheng-Qun Wang2, Qian Tang1
1Department of Dermatology, The Affiliated Hospital, Southwest Medical University, Luzhou, Sichuan, 646099, People's Republic of China.
Background:
Acne vulgaris is common and often accompanied by depression, but their linking mechanisms remain unclear. Metabolomic profiling helps identify biomarkers and perturbed pathways, so this study explores metabolic associations/pathways in acne comorbid with depression via untargeted metabolomics.
Methods:
Seventy-four acne patients were grouped by Patient Health Questionnaire-9 (PHQ-9) scores (≥10: depressive, n=21; <10: non-depressive, n=53). Their plasma was pretreated with cold methanol/acetonitrile, analyzed via Agilent 1290 Ultra-High Performance Liquid Chromatography (UHPLC)-AB Triple TOF 6600 Liquid Chromatography-Mass Spectrometry (LC-MS). Data were processed by XCMS; metabolites annotated via Human Metabolome Database (HMDB)/METLIN. Principal Component Analysis (PCA), Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were used.
Results:
We identified differential metabolites using Fold Change (FC) analysis combined with statistical significance testing, defining those with FC > 1.5 (upregulated) or FC < 0.67 (downregulated) and p < 0.05 as significant. Volcano plots and hierarchical clustering heatmaps clearly visualize these metabolites, showing distinct clustering patterns that distinguish the two groups. OPLS-DA modeling further revealed 24 key differential metabolites (VIP > 1 and p < 0.05), including 16 in positive ion mode (eg, hypoxanthine, taurine, L-tryptophan) and 8 in negative ion mode (eg, L-ascorbic acid, palmitic acid). Notably, Clustering patterns aligned with these metabolites (eg, upregulated hypoxanthine, downregulated L-ascorbic acid), confirming reliable differences. KEGG annotated 41 core pathways, with protein digestion and absorption (lowest p-value, annotated with 7 key amino acids) as a top-ranked pathway. Five amino acid metabolism-related pathways were upregulated, indicating enhanced amino acid turnover in acne patients with depression; all metabolites in the protein digestion and absorption pathway were also upregulated in this group.
Conclusion:
Hypoxanthine, taurine and branched-chain amino acids may be biomarkers for acne-depression comorbidity. Protein digestion/absorption could be a new prognostic marker/therapeutic target, with metabolic-neuroendocrine imbalance underlying the comorbidity.
