The placenta is the culprit in programming chronic disease

s / Placenta 36 (2015) A1eA60 A2 IFPASA. FETAL MEMBRANES e A FOCUS FOR THE FUTURE OR A LEGACY FROM THE PAST? A.M. Carter. University of Southern Denmark, Denmark The fetal membranes of amniotes are allantois, amnion, chorion and yolk sac. The manner of their development and contribution to placentation varies greatly acrossmammals. This is true also of the cavities they enclose, which are the allantoic sac, amniotic sac and exocoelom. In human development, there is an allantoic stalk, but no allantoic sac; the yolk sac is a short-lived structure and the exocoelom is obliterated in the second trimester by expansion of the amnion. The mouse is commonly used as a model of human placentation. Here, too, there is no allantoic sac and the exocoelom does not persist to term. In contrast, the inverted vascular yolk sac supports the embryo until the chorioallantoic placenta is formed and it acts as an accessory placenta through term. It has a string of important functions yet frequently is discarded or ignored either through ignorance or because it has no obvious equivalent in human pregnancy. In ruminants, which are important to veterinary research and as models in fetal physiology, there is yet another pattern that includes transient yolk sac placentation and a persistent allantoic sac. Embryologists of the late 19C, like Hubrecht and Selenka, uncovered the role of fetal membranes in early development and placentation. They feature prominently in the mid-20C accounts of Amoroso and Mossman. This legacy seems largely to have slipped from the collective consciousness of 21C placentologists. Yet the mouse yolk sac may harbour clues to overall placental function and human yolk sac play a critical role in embryonic development. Medical as well as veterinary research might be well served by a closer focus on fetal membranes. KEY1. THE PLACENTA IS THE CULPRIT IN PROGRAMMING CHRONIC DISEASE K. Thornburg, S. Louey. Melinda Pierce and Kevin Kolahi Center for Developmental Health, Knight Cardiovascular Institute, School of Medicine, Oregon Health and Science University, Portland, USA For the first time in US history, a sustained decrease in life expectancy is predicted. The abrupt change in the upward trajectory in life expectancy is related to increases in the prevalence of obesity, diabetes and uncontrolled hypertension, all of which have been increasing since the ‘90s. Children in the US are now the 3rd generation of people who have consumed mostly processed foods to satisfy their energy requirements. Processed foods are generally high in calories and low in nutrients. It is now well known that babies born at the extremes of birthweights are especially prone to developing chronic disease later in life. Because the placenta is the gatekeeper for nutrients entering the fetus and because the vascular bed of the placenta sets the loading conditions of the embryo/fetal heart, the placenta plays a central role in determining risk for later disease. The size and shape of the placenta interact with maternal phenotypic features to determine risk of coronary heart disease, heart failure and sudden death. Lung and colorectal cancers are predicted by placental size and shape. The number of placental cotyledons predicts blood pressure in children and umbilical cord length is associated with an elevated risk for rheumatic heart disease. Placental size, shape and efficiency in a population vary over time for unknown reasons. One can fairly speculate that population level dietary changes over time are the drivers of placentation; animal data are sparse but support the idea. Sex-specific features of placental function have been shown in humans and animals but the role of diet in altering functional changes is unknown. Understanding the interactions between maternal diet, stress, phenotype and sex-specific placental form and function should be a high priority for scientists and funding agencies. Healthy placentas make healthy babies. Healthy babies are the foundation of a healthy population KEY3. AGING AND THE PLACENTA Roger Smith. Mothers and Babies Research Centre, HMRI, Newcastle, NSW,