Effect of maternal hypercholesterolemia on fetal sterol metabolism in the Golden Syrian hamster

The fetus obtains a significant amount of cholesterol from de novo synthesis. Studies have suggested that maternal cholesterol may also contribute to the cholesterol accrued in the fetus. Thus, the present studies were completed to determine whether diet-induced maternal hypercholesterolemia would affect fetal sterol metabolism. To accomplish this, maternal plasma cholesterol concentrations were increased sequentially by feeding hamsters 0.0%, 0.12%, 0.5%, and 2.0% cholesterol. At 11 days into a gestational period of 15.5 days, cholesterol concentrations and sterol synthesis rates were measured in the three fetal tissues: the placenta, yolk sac, and fetus. In the placenta and yolk sac, the cholesterol concentration increased significantly when dams were fed as little as 0.12% cholesterol (P < 0.0167), and sterol synthesis rates decreased in dams fed at least 0.5% or 2% cholesterol, respectively (P < 0.0167). In the fetus, changes in fetal cholesterol concentration and sterol synthesis rates occurred only when dams were fed at least 0.5% cholesterol, which corresponded to a greater than 2-fold increase in maternal plasma cholesterol concentrations. When the cholesterol concentration in the fetal tissues in each animal was plotted as a function of maternal plasma cholesterol concentration, a linear relationship was found (P < 0.001). These studies demonstrate that sterol homeostasis in fetal tissues, including the fetus, is affected by maternal plasma cholesterol concentration in a gradient fashion and that sterol metabolism in the fetus is dependent on sterol homeostasis in the yolk sac and/or placenta.