Tissue sample preparations for preclinical research determined by molecular imaging mass spectrometry using matrix‐assisted laser desorption/ionization

Abstract

Matrix‐assisted laser desorption/ionization ‐ imaging mass spectrometry is an alternative tool, which can be implemented in order to obtain and visualize the “omic” signature of tissue samples. Its application to clinical study enables simultaneous imaging‐based morphological observations and mass spectrometry analysis. Application of fully informative material like tissue allows obtaining the complex and unique profile of analyzed samples. This knowledge leads to diagnosing disease, studying the mechanism of cancer development, selecting the potential biomarkers as well as correlating obtained images with prognosis. Nevertheless, it is worth noticing that this method is found to be objective but the result of the analysis is mainly influenced by the sample preparation protocol, including the collection of biological material, its preservation, and processing. However, the application of this approach requires a special sample preparation procedure. The main goal of the study is to present the current knowledge on the clinical application of matrix‐assisted laser desorption/ionization with imaging mass spectrometry in cancer research, with particular emphasis on the sample preparation step. For this purpose, several protocols based on cryosections and formalin‐fixed paraffin‐embedded tissue were compiled and compared, taking into account the measured metabolites of potential diagnostic importance for a given type of cancer.

Systematic study of tissue section thickness for MALDI MS profiling and imaging

“…18 Currently, the section thickness used in most MALDI MSI reports for biological tissues is 4–20 μm (ref. 1, 6 and 19–21) and the thickness used in each study has typically been based on previous experimental experience. Thus far, most reports on MALDI MSI have used tissue slices with thicknesses in the micrometer range.…”

Sample Preparation Method for MALDI Mass Spectrometry Imaging of Fresh-Frozen Spines

“…Prior work on fresh-frozen tissue was performed by separating the spinal cord from the surrounding bone, then using desorption electrospray ionization (DESI) MSI, − secondary ion mass spectrometry (SIMS) MSI, , or MALDI MSI. , As such, we have aimed to image nondecalcified, fresh-frozen spinal cord while it is still surrounded by the corresponding bone and muscle to best preserve and visualize its native metabolic features. In brief, the MALDI MSI workflow requires successful tissue preparation for data acquisition, making methods for tissue preparation an important area of research in the field. , Sectioning the tissue to a thickness of approximately 8–12 μm, with thinner sections resulting in a better signal-to-noise ratio, is a major requirement of MALDI MSI. For this reason, a method for sectioning the spinal column without disturbing its native chemical architecture is necessary.…”

“…In brief, the MALDI MSI workflow requires successful tissue preparation for data acquisition, making methods for tissue preparation an important area of research in the field. 63 , 64 Sectioning the tissue to a thickness of approximately 8–12 μm, 65 with thinner sections resulting in a better signal-to-noise ratio, 66 is a major requirement of MALDI MSI. For this reason, a method for sectioning the spinal column without disturbing its native chemical architecture is necessary.…”

Spatial lipidomics of fresh-frozen spines

“…In brief, the MALDI MSI workflow requires successful tissue preparation for data acquisition, making methods for tissue preparation an important area of research in the field 63,64 . Sectioning the tissue to a thickness of approximately 8-12 µm 65 , with thinner sections resulting in a better signal-to-noise ratio, 66 is a major requirement of MALDI MSI. For this reason, a method for sectioning the spinal column without disturbing its native chemical architecture is necessary.…”