Glycan labeling strategies and their use in identification and quantification

Most methods for the analysis of oligosaccharides from biological sources require a glycan derivatization step: glycans may be derivatized to introduce a chromophore or fluorophore, facilitating detection after chromatographic or electrophoretic separation. Derivatization can also be applied to link charged or hydrophobic groups at the reducing end to enhance glycan separation and mass-spectrometric detection. Moreover, derivatization steps such as permethylation aim at stabilizing sialic acid residues, enhancing mass-spectrometric sensitivity, and supporting detailed structural characterization by (tandem) mass spectrometry. Finally, many glycan labels serve as a linker for oligosaccharide attachment to surfaces or carrier proteins, thereby allowing interaction studies with carbohydrate-binding proteins. In this review, various aspects of glycan labeling, separation, and detection strategies are discussed

Glycosylation of plasma IgG in colorectal cancer prognosis

In this study we demonstrate the potential value of Immunoglobulin G (IgG) glycosylation as a novel prognostic biomarker of colorectal cancer (CRC). We analysed plasma IgG glycans in 1229 CRC patients and correlated with survival outcomes. We assessed the predictive value of clinical algorithms and compared this to algorithms that also included glycan predictors. Decreased galactosylation, decreased sialylation (of fucosylated IgG glycan structures) and increased bisecting GlcNAc in IgG glycan structures were strongly associated with all-cause (q < 0.01) and CRC mortality (q = 0.04 for galactosylation and sialylation). Clinical algorithms showed good prediction of all-cause and CRC mortality (Harrell’s C: 0.73, 0.77; AUC: 0.75, 0.79, IDI: 0.02, 0.04 respectively). The inclusion of IgG glycan data did not lead to any statistically significant improvements overall, but it improved the prediction over clinical models for stage 4 patients with the shortest follow-up time until death, with the median gain in the test AUC of 0.08. These glycan differences are consistent with significantly increased IgG pro-inflammatory activity being associated with poorer CRC prognosis, especially in late stage CRC. In the absence of validated biomarkers to improve upon prognostic information from existing clinicopathological factors, the potential of these novel IgG glycan biomarkers merits further investigation

Glycomics using mass spectrometry

Mass spectrometry plays an increasingly important role in structural glycomics. This review provides an overview on currently used mass spectrometric approaches such as the characterization of glycans, the analysis of glycopeptides obtained by proteolytic cleavage of proteins and the analysis of glycosphingolipids. The given examples are demonstrating the application of mass spectrometry to study glycosylation changes associated with congenital disorders of glycosylation, lysosomal storage diseases, autoimmune diseases and cancer

Data Standardization within Pediatrics: BPCRN’s analysis of trials identifying cross-cutting data points

Background/Aims: The conect4children (c4c) consortium, funded by Innovative Medicines Initiative (IMI2), was created in 2018 consisting of 20 national networks within Europe to facilitate and optimize clinical trials in children. One of the main aims of c4c is to improve standardization and reusability of trial data. A partnership was formed between c4c and the Clinical Data Interchange Standards Consortium (CDISC) to develop a novel Pediatric User Guide (PUG), involving a standardized definition of each cross-cutting pediatric-specific data point which is routinely collected in clinical trials. Method: A pediatric resident, a data manager and clinical research coordinator (CRC) of a university site were involved from the Belgian Paediatric Clinical Research Network. A review of the clinical trials performed between 2018 and December 2020 collected recurring pediatric-specific data points. More than 20 meetings were held to discuss these findings and identify priorities for standardized definition and inclusion in a paediatric data standard. For the review of the first selection of harmonized definitions, the national hub shared the call for experts with 15 sites. Two experienced sub-specialized experts reviewed the collected cross-cutting pediatric harmonized definitions. Results: For the first phase of harmonized definitions, within SPD-D.R.U.G. (clinical trial unit in Ghent University Hospital) around 51 trials were reviewed and over 35 cross-cutting data definitions were added. The pediatric resident added additional 5 suggestions and prioritization of clinical practice based on the experience of over 10 clinical trials. In the second phase, the two experts from Ghent University hospital reviewed the subset of harmonized definitions for priorities in the final inclusion. Conclusion: Clinical Trial Unit and national expertise requests in the development as well as translation of a paediatric data standard within an academic clinical setting is beneficial in the development of clinically realistic data standards