A Potential Role for GSK3ß in Glucose-Driven Intrauterine Catch-Up Growth in Maternal Obesity.

Obesity and unhealthy nutrition are increasing and affect women of childbearing age and hence during pregnancy. Despite normal or even high birth weight, the offspring suffers from long-term metabolic risks. We hypothesized that fetal growth is disturbed during different intrauterine phases. Underlying molecular events remain elusive. Female mice were fed either a standard diet (SD) or a high-fat diet (HFD) after weaning until mating and during pregnancy. Pregnant mice were euthanized at gestational day (G)15.5 and G18.5, and fetuses and placentas were removed for analysis. HFD fetuses displayed intrauterine growth restriction (IUGR) at G15.5, which disappeared until G18.5, indicating intrauterine catch-up growth during that time period. Main placental findings indicate decreased canonical Wnt-GSK3ß signaling and lower proliferation rates at G18.5, which goes along with a smaller placental transfer zone. On the other hand, glucose depots (glycogen cluster) in HFD placentas decreased more strongly between G15.5 and G18.5 compared with placentas from SD mothers, and the glucose transporter protein GLUT-1 was increased at G18.5 in the HFD group. Maternal diet-induced obesity causes an IUGR phenotype at the beginning of the third week (G15.5) in our mouse model. This phenotype is reversed by the end of the third week (G18.5) despite a smaller placental transfer zone, probably based on GSK3ß-mediated increased glucose mobilization in the placenta and hence an increased glucose supply to the fetus.

Maternal obesity attenuates predelivery inflammatory reaction in C57BL/6N mice.

Inflammation and oxidative stress are known to increase before labour. Whether gonadal white adipose tissue (gWAT) participates in this process and whether labour-related processes in placental and adipose tissue are altered in obese women is unknown. In our mouse model, lean mice display elevated placental inflammation and oxidative stress towards the end of pregnancy, accompanied by an increased expression of pro-inflammatory factors in gWAT. Obese mice also display elevated levels of pro-inflammatory factors and oxidative stress in placentas shortly before birth. However, placental infiltration with leukocytes and an increase in gWAT pro-inflammatory factor expression in obese dams are lacking.