Endocrine Abstracts

Background/objective: We have shown that expression of maternal serum human chorionic gonadotrophin (hCG) oligossacharides in uncomplicated pregnancy differs from that seen in pregnancy complicated by maternal type1 diabetes mellitus. Whether this observed oligosaccharide heterogeneity in type1 diabetes is specific to hCG or represents a more general phenomenon amongst placental oligosaccharides is not known. The oligosaccharide distribution in placentas from pregnancies complicated by type 1 diabetes may be related to the morphofunctional alterations observed in the placental components of such pregnancies, ultimately providing adverse conditions for the foetus.

Method: We used a lectin affinity histochemical evaluation of the distribution of glycoconjugates in human placentas from physiological pregnancies and from pregnancies of women with type1 diabetes. Concanavalin A, Lens culinaris agglutinin, wheat germ agglutinin and peanut agglutinin (Con A, LCA, WGA, and PNA respectively) were tested for their binding to villous sycytiotrophoblasts (VSCT), villous endothelial cells (EC) and extravillous decidual trophoblasts (EVT) in fixed sections of placenta. Lectin binding and intensity was assessed by an histopathologist, blinded to the clinical outcome, using Quickscore Method. Comparison of samples was by t-test for unpaired samples.

Results: Comparing data from control (group1) and diabetes (group 2) populations

1. Greater LCA affinity in VSCT (P<0.05) and EC (P<0.05), group 1 versus group 2

2. Reduced PNA affinity in EC (P<0.05), group 1 versus group 2

3. Similar LCA and WGA affinity in groups 1 and 2

Conclusion: In type1 diabetes changes in the distribution of oligosaccharides may be related to altered structure and function of the placenta. The findings of this study indicate modified physiological pathways in pathological pregnancies; the need for further research is required to gain a more comprehensive understanding of how cell populations are affected by pathological conditions, in order to understand the role of oligosaccharide structure in normal pregnancies.