This study applies an established workflow for profiling protein N-glycosylation from dried blood spots (DBS) using ultra-high-performance liquid chromatography with hydrophilic interaction and fluorescence detection (HILIC-UHPLC-FLR). The laboratory protocol described includes physical DBS cutting, protein extraction and enzymatic digestion, fluorescent labeling with 2-aminobenzamide, cleanup steps, and subsequent HILIC-UHPLC-FLR measurement. The method adapts conventional glycomics sample preparation to the DBS matrix to permit N-glycan analysis from small, dried blood specimens.
Authors compared DBS-derived N-glycan profiles with those obtained from plasma and evaluated how different blood preparations affect the DBS N-glycome. The preparations assessed included DBS prepared from fresh whole blood, DBS prepared from frozen whole blood, and DBS prepared from combinations of separated frozen blood cells with corresponding frozen plasma. The manuscript reports that DBS N-glycosylation profiles are comparable across these preparation types, supporting interchangeability of different starting materials for DBS N-glycan analysis.
A central finding is that the DBS N-glycosylation profile is stable regardless of whether DBS were generated from fresh or frozen blood preparations. This stability implies that samples collected or stored under different conditions, including frozen whole blood initially not intended for glycomic analysis, can be repurposed for N-glycan profiling. The ability to analyze retrospective or convenience samples enhances the method's utility for biomarker discovery or large-scale screening where plasma was not archived.
The authors compared DBS N-glycan features in samples from pre-diabetic and diabetic subjects. They report directional trends in several derived glycan traits: fucosylation, bisection, and galactosylation showed an increasing trend in diabetes, while sialylation showed a decreasing trend in diabetes. However, these observed trends did not reach statistical significance in the comparisons reported. The manuscript does not provide peer-reviewed confirmation of diagnostic performance; the findings are presented as preliminary observations in a preprint.
The study emphasizes practical strengths of DBS-based N-glycan profiling: DBS sampling is minimally invasive, easier and cheaper to collect, transport, and store compared with conventional plasma collection, and it reduces biohazard risk. These operational benefits, combined with the reported stability of the N-glycome across different blood preparations, support DBS as an accessible approach for N-glycan biomarker analysis in the context of pre-diabetes and diabetes monitoring. The authors note the principal advantage of repurposing samples not originally collected for glycomics, such as frozen whole blood.
Limitations are noted implicitly by the presentation: the comparisons of glycan traits between pre-diabetes and diabetes yielded non-significant trends, and the report is a preprint that has not undergone peer review. Detailed quantitative results, cohort sizes, and specific statistical metrics are not repeated here and should be consulted in the source document for full appraisal.
Disclosure in the source specifies that G.L. is the founder and owner of Genos Ltd, a company specializing in high-throughput glycomic analysis; I.T-A. is an employee of Genos Ltd; and E.M. was employed by Genos Ltd at the time of the work. Funding declared includes support for E.M. from the European Union’s Horizon 2020 Marie Skłodowska-Curie program (project GlySign). The funder was not involved in study design, data collection, analysis, interpretation, manuscript writing, or publication decisions.
The authors conclude that DBS N-glycan profiling by HILIC-UHPLC-FLR is a feasible, stable, and practical method for analyzing protein N-glycosylation from a variety of blood preparations. While directional glycan changes consistent with diabetes biology were observed (increased fucosylation, bisection, galactosylation; decreased sialylation), these were not statistically significant in the reported comparisons. The combination of ease, low cost, minimal invasiveness, and the capacity to repurpose archived or frozen samples positions DBS N-glycan profiling as a promising approach for larger scale studies and potential implementation in diagnostics and monitoring pathways for pre-diabetes and diabetes, pending further validation and peer-reviewed confirmation.