LC-MS metabolomics reveal skin metabolic signature of psoriasis vulgaris.

Recent metabolic studies have indicated that several metabolites in blood and urine of psoriasis functionally involved in the pathogenesis of psoriasis, but the skin metabonomics research of psoriasis is limited. We aimed to investigate the metabolic profiling of lesional and nonlesional skin and screen out potential biomarkers for psoriasis. We performed liquid chromatography-mass spectrometry (LC-MS)-based nontargeted metabolomic analysis to compare metabolic profile between lesional and nonlesional skin from 12 patients with psoriasis vulgaris. A total of 3463 metabolites were detected, of which 769 (346 named and 423 unnamed) in positive ion mode and 179 (80 named and 99 unnamed) in negative ion mode were significantly different between lesional and nonlesional skin. These different metabolites were mainly derived from amino acid, lipid and nucleotide metabolism, and involved in cell proliferation and apoptosis regulation. Fourteen metabolites (10 upregulated and 4 downregulated) were identified as the most potentially significant biomarkers. Interestingly, seven of them were positively (l-gamma-glutamyl-l-leucine, 2-methylcitric acid, l-palmitoylcarnitine, inosine, eicosapentaenoic acid and 13-hydroxy-octadecaenoic acid) or negatively (l-serine) correlated with disease severity. Significant differences of metabolic characteristics were found between lesional and nonlesional skin, which may contribute to assess the severity of psoriasis and therapeutic responses.