Investigation of potential biomarkers for psoriasis in skin with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and ambient ionization mass spectrometry

Background: Psoriasis is a chronic inflammatory disease with an unclear etiology that affects skin, nails, and joints and often accompanies comorbidities. Recent studies indicate that alterations in metabolites within psoriatic lesions might be linked to inflammation. Studying bioactive lipid mediators or metabolites in skin inflammation and immunity might provide new potential biomarkers and therapeutic prediction factors. Methods: Lipids and peptides in the scale extracts from psoriasis patients and healthy controls were characterized by thermal desorption-electrospray ionizationmass spectrometry and matrix-assisted laser desorption/ionization time-of-flightmass spectrometry, respectively. Principal component analysis (PCA) was then applied to these data to identify potential differences between psoriasis patients and healthy controls. Results: Psoriatic plaques show reduced wax esters and triglycerides and a predominant increase in human neutrophil defensins (HNPs), compared to non-lesional sites of psoriatic patients and healthy control. Additionally, when medical treatments were administered to psoriasis patients, levels of HNPs were significantly reduced, suggesting that they may serve as potential biomarkers to evaluate therapeutic efficacy for psoriasis. Conclusion: Two mass spectrometric techniques were used to rapidly and non-invasively identify and monitor potential biomarkers between psoriasis patients and healthy controls. However, PCA results only showed slight differences, and we intend to broaden the sample base in the future to increase the statistical power of the investigation.