Facilitated by substantial advances in analytical methods, plasma N-glycans have emerged as potential candidates for biomarkers. In the recent years, several investigations could link aberrant plasma N-glycosylation to numerous diseases. However, due to often limited specificity and sensitivity, only a very limited number of glycan biomarkers were approved by the authorities up to now.
The inter-individual heterogeneity of the plasma N-glycomes often mask small disease related changes in conventional large cross-sectional cohort studies, with a one-time per person sampling approach. This problem could be overcome by a longitudinal sampling approach, detecting already small changes during disease progression by monitoring the plasma N-glycome of individuals over time.
To evaluate this, we collected blood plasma samples of five healthy donors over a time period of up to six years. The plasma N-glycome was analyzed by utilizing multiplexed capillary gel electrophoresis with laser induced fluorescence detection (xCGE-LIF) as core technology . By using this miniaturized electrokinetic separation technique with up to 96 capillaries in parallel, assisted by a 96-well format sample preparation and an automated data analysis by glyXtool™, a massive reduction of analysis time and costs per sample could be achieved.
We could demonstrate that the individual’s N-glycome is remarkably stable over a period of several years and free of seasonal changes. Furthermore, we could demonstrate that the inter-individual differences of the N-glycome are enormous, but by looking at the progression of the plasma N-glycome of a single person, small changes could be detected and linked to lifestyle and environmental factors. Consequently, we could show that a longitudinal sampling approach (taking time-series from individuals) can be beneficial compared to large-scale studies, where small disease related changes in the N-glycome are often hidden within the inter-individual variation of the N-glycome .