2025 Volume 4 Issue 2 Pages 107-116
Lipidomics research has accelerated in recent years because of advances in mass spectrometry technology. Imaging mass spectrometry (IMS) is a powerful technique to obtain comprehensive molecular information for identification of lipids and their localization in tissues to explore the underlying pathogenesis of skin diseases, including atopic dermatitis, asteatosis, and ichthyosis. The aim of this study was to compare and perform molecular localization analysis of porcine and human skin lipids by high-resolution matrix assisted laser desorption/ionization (MALDI)-IMS using 9-Aminoacridine (9AA) matrix. 9AA was vapor-deposited onto the thinly sliced skin samples as a matrix to promote ionization of the analyte molecule following laser irradiation. We successfully visualized various skin lipids of both species localized in three different skin layers (stratum corneum, viable epidermis, and dermis) by this method. Molecules with peaks at m/z 465.305, 474.361, and 659.394 were mainly localized in the stratum corneum, those with peaks at m/z 184.076, 273.042, 378.159, 570.228, and 579.228 were localized in the viable epidermis, and those with peaks at m/z 607.361, 615.201, 659.192, 687.545, and 703.571 were localized in the dermis in both species. However, peaks at m/z 465.305 and 659.394 were assigned to cholesterol sulfate and were localized exclusively in the stratum corneum in porcine skin, but abundant in the granular layer in human skin. In conclusion, we performed MALDI-IMS using 9AA matrix and found most of the lipid molecules in porcine and human skin showed similar distributions. However, there were some differences including the localization of cholesterol sulfate.
