MALDI mass spectrometry imaging in rheumatic diseases

- Studies using MALDI-MSI on samples from the human joint have been carried out recently.
- This technique has proven usefulness for obtaining complementary information to histology in rheumatic disorders.
- Several peptides and proteins have been identified and localized in cartilage and synovium by MALDI-MSI analysis.
- The snap-frozen method is particularly good for imaging peptides in cartilage slices compared to FFPE samples.
- Specific examples of the tryptic peptide distributions obtained by MALDI-MSI of osteoarthritic cartilage samples are provided.

Mass spectrometry imaging (MSI) is a technique used to visualize the spatial distribution of biomolecules such as peptides, proteins, lipids or other organic compounds by their molecular masses. Among the different MSI strategies, MALDI-MSI provides a sensitive and label-free approach for imaging of a wide variety of protein or peptide biomarkers from the surface of tissue sections, being currently used in an increasing number of biomedical applications such as biomarker discovery and tissue classification. In the field of rheumatology, MALDI-MSI has been applied to date for the analysis of joint tissues such as synovial membrane or cartilage. This review summarizes the studies and key achievements obtained using MALDI-MSI to increase understanding on rheumatic pathologies and to describe potential diagnostic or prognostic biomarkers of these diseases. This article is part of a Special Issue entitled: MALDI Imaging, edited by Dr. Corinna Henkel and Prof. Peter Hoffmann.

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