Figure 2.

The sialoglycan level trends in normal pregnancy period and preeclampsia. (A) The sialoglycan level curves in normal pregnancy amniotic fluid were simulated based on the results of normal pregnant women by Magdalena et al (14). The α2,3-sialoglycans refer to the glycans detected by Maackia amurensis (MAA). The α2,6-sialoglycans refer to the glycans detected by Sambucus nigra (SNA). The relative amounts of α2,3-sialoglycans and α2,6-sialoglycans were positively related to the age of pregnancy. The α2,3-sialoglycans and α2,6-sialoglycans both reach the highest point during the post-date pregnancy. The α2,3-sialoglycans are significantly elevated in post-date pregnancy compared to the 3rd trimester (the blue curve). The α2,6-sialoglycans gradually rise from the 2nd trimester to the perinatal period, and thereafter decrease to a level similar to that of the 3rd trimester during delivery (the orange curve). (B) The sialic acid levels change while preeclampsia. Compared to the normal pregnancy, the concentration of total sialic acid in the saliva significantly increased; the total sialic acid levels in serum showed no significant difference (marked with †); levels of α2,6-sialoglycans in the syncytium elevated, while that of α2,3-sialoglycans in the endothelium of terminal villi decreased. (C) Sialoglycans play roles in gamete transit and fertilization. The negatively charged sialoglycan coat of sperm renders them to escape the immune-mediated clearance and assists in sperm maturation and fertilization within the FRT.