1Comparative Primate Biology Laboratory, University of Illinois at Chicago, 2St. Kitts Biomedical Research Foundation, 3RxGen, 4Departments of Psychiatry and Neurobiology, Yale University, 5Department of Oral Biology, University of Illinois at Chicago
Saturday All day, Plaza Level
Little is known about placental growth and morphology across gestation in nonhuman primates. A rare time-series of 50 vervet monkey (Chlorocebus sabaeus) placentas from the St. Kitts Biomedical Research Foundation was characterized in terms of gross morphology and shifts in efficiency across the latter half of a species-typical 167-day gestation. Although both fetal mass and placental mass increased significantly with gestational age (Pearson’s correlations: r=0.85, p<0.001; r=0.64, p<0.01, respectively), growth was not symmetrical. Placental efficiency during period 2 (d. 131-159) was 43% greater than that of period 1 (d. 83-130) (T-test: t=-3.60, p<0.001), with placental mass accrual slowing at day 130 while fetal mass continued to increase. This suggests there is an important shift in the metabolic capacity of the placenta, perhaps in relation to investment in developmental events such as brain growth. This slowing of gross increases in placental mass is coupled with an expansion of the microscopic surface area of the villi with associated increases in topographical complexity, a mechanism by which nutrient and oxygen exchange increases to support the energetic burden of late gestation brain and somatic growth. A better understanding of how the placenta drives and constrains fetal and brain growth in anthropoid primates is directly relevant to developmental models of human brain evolution
This study was directly funded by an American Association of Physical Anthropologists Career Development Grant and a Building Interdisciplinary Research Careers in Women’s Health (BIRCWH) faculty scholarship from the National Institute of Child Health and Human Development and the National Institutes of Health Office of Research on Women’s Health (K12HD055892).