Renopathological Microstructure Visualization from Formalin Fixed Kidney Tissue by Matrix-Assisted Laser/Desorption Ionization-Time-of-Flight Mass Spectrometry Imaging

Understanding early stage renal malfunctions with regard to the glomerular filtration processes is essential for nephropathological prescreening strategies and intervention at an early stage. Mass spectrometry imaging (MSI) in combination with histopathology can provide an universal analytical approach. Proteomic and lipidomic aspects of glomerular biocompositions were applied for micro-structural differentiation in healthy rat kidney samples. Usability of commonly used tissue embedding media and the compatibility of histological staining and fixation methods were of interest. It was demonstrated that ultra-thin tissue samples (500 nm, 1 and 10 μm) can be used for lipid and peptide-based differentiation at the glomerular resolution level in formalin-fixed tissue samples in combination with preceding histological staining for correlating optical and molecular mass images.