N-glycan profiling in the study of human aging.

Most secreted proteins produced by the human body are modified by glycosylation. It is well known that the oligosaccharides (glycans) of glycoproteins are important for initiation of various cellular recognition signals that are essential for the maintenance of the ordered social life of each cell within a multi-cellular organism. The sugar chains can be altered by the physiological or pathophysiological condition of the cell. We describe a detailed protocol for the analysis of N-linked glycans in blood via DNA sequencing equipment-Fluorophore Assisted Carbohydrate Electrophoresis (DSA-FACE). The key features of this technique are its robustness, high throughput, high sensitivity and reliable quantification. Based on DSA-FACE technology, we previously reported that N-glycan profiling of the human serum shows substantial changes with increasing age in three major N-glycan structures. We proposed that measurement of the N-glycan level changes could provide a surrogate marker for general health or for age-related disease progression, and for monitoring the improvement of health after therapy.