Human milk oligosaccharides (HMO) are bioactive polysaccharides found in breast milk. The best research has been done on their contribution to the development of a healthy infantile intestinal flora, as HMO are absorbed into the child’s gastrointestinal tract through breastfeeding. In addition, they were detected in the mother’s bloodstream early in pregnancy, which is why they play an important role for mother and child even before birth.
In a recently published work, researchers at Med Uni Graz were able to show that changes in the maternal sugar metabolism caused by gestational diabetes are associated with changes in the HMO profile in the blood. The team is now investigating whether this also has an impact on umbilical cord blood and placental blood vessel formation.
Consequences of elevated maternal blood sugar levels
Gestational diabetes is a disorder of the maternal sugar metabolism that occurs for the first time during pregnancy. It affects up to ten percent of all pregnancies and is characterized by elevated maternal blood sugar levels. Gestational diabetes can have acute and long-term consequences for the health of both the mother and the child.
As with other forms of diabetes, high blood sugar can affect how blood vessels and the cells that line them (endothelial cells) work. The placenta forms at the beginning of pregnancy and continues to develop. It transports oxygen, nutrients and also HMO to the child and removes waste products. In the process, their blood vessel system is constantly being expanded and redesigned, one of the basic factors being extensive new blood vessel formation (angiogenesis). Maternal metabolic disorders such. B. Gestational diabetes can affect processes of angiogenesis and consequently lead to structural changes in the blood vessel system of the placenta.
Function in maternal and child circulation
At the University Clinic for Gynecology and Obstetrics at Med Uni Graz, Evelyn Jantscher-Krenn researches the occurrence, function and influence of HMOs on mother and child. In an earlier study, the researcher and her colleagues were able to show that HMO can already be detected in the maternal circulation during pregnancy. They get into the child’s blood via the placenta, which raises questions about their importance for the blood vessels of the placenta. Its composition varies from person to person and is similar to that in breast milk. It depends on genetic factors, the week of pregnancy and the mother’s metabolic status.
The researchers have already been able to show that in a group of overweight and obese women, those who developed gestational diabetes had increased concentrations of a specific HMO, 3’sialyllactose (3’SL). “We are investigating whether gestational diabetes can also lead to changes in HMO in the child’s circulatory system and what effects polysaccharides have on the cells of the placenta,” says Evelyn Jantscher-Krenn.
Effects on placenta?
In a new, recently published study, the research team examined the composition and concentration of HMO in infant cord blood after delivery. The study participants were divided into two groups: mothers after uncomplicated pregnancies with normal sugar metabolism and mothers with gestational diabetes. The concentration of 3’SL in the child’s umbilical cord blood was significantly increased after gestational diabetes, which shows that an altered maternal metabolism also leads to altered HMO concentrations in the child’s bloodstream.
Furthermore, the influence of HMO on the angiogenesis of the placenta was investigated. For this purpose, endothelial cells were obtained from the placenta after healthy pregnancies and the process of angiogenesis was analyzed in vitro with the addition of HMO. This included the reorganization of cell shape, cell movement, the ability to divide and multiply, and the formation of sprouts. Both a pool of different HMOs and 3’SL alone stimulated the mentioned steps of angiogenesis in vitro.
“Possibly in the context of gestational diabetes there is an adaptation of the HMO compositions, which stimulate the formation of new blood vessels in the placenta in order to ensure the child’s care. If these effects on placental blood vessel cells also apply in vivo, HMO could play an important role for the regulation of angiogenesis for mother, placenta and child – even in a healthy pregnancy,” says the researcher. In the future, they want to find out which mechanisms underlie the influence of HMO on blood vessel formation.
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