Simple Summary The detection of colorectal cancer (CRC) at an early stage is increasing due to the implementation of screening programs. Local excision of early CRC is potentially curative, however... Show moreSimple Summary The detection of colorectal cancer (CRC) at an early stage is increasing due to the implementation of screening programs. Local excision of early CRC is potentially curative, however the identification of early lesions at high risk of regional metastases remains challenging, and greatly influencing therapy decision making. Variations in sugar molecules has been associated with development and progression in various cancer types including CRC. Therefore, we examined these sugar signatures, so-called N-glycans, in different stages of progression of CRC starting from epithelium to pre-cancerous and cancerous tissue. We report that the sugar signatures clearly differentiate each step of CRC progression, especially between pre-cancerous and cancerous tissue. We also observed some of the glycosylation signatures of the cancerous areas to be spreading into the tumor microenvironment. The increase incidence of early colorectal cancer (T1 CRC) last years is mainly due to the introduction of population-based screening for CRC. T1 CRC staging based on histological criteria remains challenging and there is high variability among pathologists in the scoring of these criteria. It is crucial to unravel the biology behind the progression of adenoma into T1 CRC. Glycomic studies have reported extensively on alterations of the N-glycomic pattern in CRC; therefore, investigating these alterations may reveal new insights into the development of T1 CRC. We used matrix-assisted laser desorption ionization (MALDI) mass spectrometry imaging (MSI) to spatially profile the N-glycan species in a cohort of pT1 CRC using archival formalin-fixed and paraffin-embedded (FFPE) material. To generate structural information on the observed N-glycans, CE-ESI-MS/MS was used in conjunction with MALDI-MSI. Relative intensities and glycosylation traits were calculated based on a panel of 58 N-glycans. Our analysis showed pronounced differences between normal epithelium, dysplastic, and carcinoma regions. High-mannose-type N-glycans were higher in the dysplastic region than in carcinoma, which correlates to increased proliferation of the cells. We observed changes in the cancer invasive front, including higher expression of alpha 2,3-linked sialic acids which followed the glycosylation pattern of the carcinoma region. Show less
Background Degeneration of shoulder muscle tissues often result in tearing, causing pain, disability and loss of independence. Differential muscle involvement patterns have been reported in tears... Show moreBackground Degeneration of shoulder muscle tissues often result in tearing, causing pain, disability and loss of independence. Differential muscle involvement patterns have been reported in tears of shoulder muscles, yet the molecules involved in this pathology are poorly understood. The spatial distribution of biomolecules across the affected tissue can be accurately obtained with matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI). The goal of this pilot study was to decipher the metabolic landscape across shoulder muscle tissues and to identify signatures of degenerated muscles in chronic conditions. Methods Paired biopsies of two rotator cuff muscles, torn infraspinatus and intact teres minor, together with an intact shoulder muscle, the deltoid, were collected during an open tendon transfer surgery. Five patients, average age 65.2 +/- 3.8 years, were selected for spatial metabolic profiling using high-spatial resolution (MALDI-TOF) and high-mass resolution (MALDI-FTICR) MSI in negative or positive ion mode. Metabolic signatures were identified using data-driven analysis. Verifications of spatial localization for selected metabolic signatures were carried out using antibody immunohistology. Results Data-driven analysis revealed major metabolic differences between intact and degenerated regions across all muscles. The area of degenerated regions, encompassed of fat, inflammation and fibrosis, significantly increased in both rotator cuff muscles, teres minor (27.9%) and infraspinatus (22.8%), compared with the deltoid (8.7%). The intact regions were characterized by 49 features, among which lipids were recognized. Several of the identified lipids were specifically enriched in certain myofiber types. Degenerated regions were specifically marked by the presence of 37 features. Heme was the most abundant metabolite in degenerated regions, whereas Heme oxygenase-1 (HO-1), which catabolizes heme, was found in intact regions. Higher HO-1 levels correlated with lower heme accumulation. Conclusions Degenerated regions are distinguished from intact regions by their metabolome profile. A muscle-specific metabolome profile was not identified. The area of tissue degeneration significantly differs between the three examined muscles. Higher HO-1 levels in intact regions concurred with lower heme levels in degenerated regions. Moreover, HO-1 levels discriminated between dysfunctional and functional rotator cuff muscles. Additionally, the enrichment of specific lipids in certain myofiber types suggests that lipid metabolism differs between myofiber types. The signature metabolites can open options to develop personalized treatments for chronic shoulder muscles degeneration. Show less
The work presented in this thesis describes the improvement and application of on-tissue chemistry for in-situ biomolecular analysis using matrix assisted-laser desorption/ionization mass... Show moreThe work presented in this thesis describes the improvement and application of on-tissue chemistry for in-situ biomolecular analysis using matrix assisted-laser desorption/ionization mass spectrometry imaging (MALDI-MSI). We have proposed new methodologies, applying on-tissue (enzymatic) chemistry, to increase the molecular information obtained in a MALDI-MSI analysis. We have also developed an automated histology-guided MSI platform, based on state-of-the-art image processing tools, to facilitate high mass and spatial resolution MALDI-MSI while maintaining reasonable data loads and acquisition times. We have shown the importance of these methods in a clinical biomarker discovery study on myxoid liposarcoma tissues. Show less
