Human Milk Oligosaccharides: Emerging Roles in Gestational Diabetes

Human milk oligosaccharides, unconjugated, soluble oligosaccharides produced by the mammary gland, have a multitude of functional properties with potential long-lasting effects on immune system or metabolism. Traditionally studied in human milk, we now know that HMOs are also detectable already in early in gestation in maternal blood, urine, amniotic fluid and cord blood 1-5. This suggests intense HMO exposure to mother and child, independent of breastfeeding, and thus, biological roles for HMOs in pregnancy. How HMOs are influenced by maternal factors such as the glucometabolic status, and whether altered HMO profiles affect pregnancy outcomes or fetal/maternal programming remains to be investigated. Previously, we found that a specific HMO, 3’-sialyllactose (3’SL), in maternal serum predicted subsequent gestational diabetes mellitus (GDM) in an at-risk cohort of overweight and obese pregnant women 2. In another study in normal weight women, we showed that 3’SL in cord blood was increased after pregnancies complicated with GDM. 3’SL promoted in vitro angiogenesis in feto-placental endothelial cells 3, suggesting roles in placental adaptation to meet hyperglycemia induced increases in fetal supply needs. In a recent study in a well characterized prospective pregnancy cohort, we found maternal serum 3’SL concentrations significantly increased during an oral glucose tolerance test (OGTT), and negatively associated with insulin sensitivity. These changes in 3’SL upon glucose load might also suggest roles for HMOs in mediating metabolic adaptations during healthy pregnancy. This talk will recapitulate the emerging roles of HMOs in GDM as potential biomarkers and/or mediators of adaptations and programming events during pregnancy.