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Collaborators Michael Yampolsky, PhD
Collaborators Michael Yampolsky, PhD
 Michael Yampolsky, PhDAssociate Professor - University of Toronto,Department of Mathematics University Profile/Website Downloads (right click and select "save target as") Michael Yampolsky - Biosketch Research Posters (right click and select "save target as") Placental Shapes may Reflect Timing but not Severity of Perturbed Vascular Growth Towards understanding the fetal origins of adult diseases: Analysis of placental shapes Dr. Carolyn Salafia works Prof. Michael Yampolsky from the University of Toronto in developing measures of placental shape and the chorionic surface vasculature that it contains. The placental chorionic vasculature is a complex branching structure laid down in the first months of pregnancy which our measures demonstrate affect fetal growth throughout pregnancy. We are currently assessing a fractal model, perturbations of which reproduce the complex three-dimensional shapes she has measured in complicated pregnancies from a modern birth cohort.1 Fetal programming. Early life influences adult diseases. Such serious public health priorities as diabetes, heart disease, breast and prostate cancer, osteoporosis, and depression have all been related by recent medical studies to the development of the fetus. 2,3 Environmental influences, such as maternal diseases, can cause irreversible metabolic consequences for the fetus, altering susceptibility to later adverse outcomes. This effect is known as fetal programming. Among its well-documented causes are such maternal diseases as diabetes and preeclampsia, and maternal exposure to smoking. Deviation from a normal development of a fetus can also be mark a genetic predisposition to adult health risks. If we can understand the processes by which the fetus is altered and develops risks for lifelong disease, we may be better able to protect the child and the adult. We may also be able to devise obstetric surveillance and interventions to protect the fetus from key intrauterine stresses. Fortunately, every baby is born with a “crystal ball” for determining the problems of its fetal development – the placenta.
Why study the placenta? Before birth, the placenta is our sole source of oxygen and nutrients. It is a principal regulator of fetal growth and health, faithfully recording developmental stressors. After birth it can be immediately assessed, without any interference with the newborn. Recent work 5-7 has established a causal link between maternal stresses and genetic influences adversely affecting the development of the placenta and known adult health risk factors. The structure of the placenta. A typical placenta has a round shape, with the umbilical cord inserted roughly at the centre. From the insertion point, as from a root, grow repeatedly branching blood vessels, forming the vascular tree. The branches of the tree fill the placental disk of a round shape and uniform thickness. However, in about a third of the cases the placenta develops differently. The round disk is replaced by a less regular shape. Most notably, it can become “star-like”, or grow several lobes. As shown in 5, these changes reflect the changes in the underlying vascular tree structure.
Metabolic efficiency of the placenta as a biologically relevant fractal dimension of the vasculature. As shown in 6 the fractal structure of the placental vasculature is manifested in the non-trivial scaling of the birth weight of the fetus with the placental weight. The scaling exponent 1/β (β≈0.75 6) for a normal placenta is a biologically relevant fractal dimension of the placental vascular tree. Abnormal vascular branching results in a higher value of β. 7 The value of β is an important clinical marker, which sensitively responds to such adult health risks as preeclampsia and maternal diabetes, which are known to modify fetal-placental vascular development.
1. C. Salafia, E. Maas, J. Thorp, B. Eucker, J. Pezzullo, D. Savitz. Measures of Placental Growth in Relation to Birth Weight and Gestational Age. American Journal of Epidemiology 162(2005) 2. M.J. Nijland, S.P. Ford, P.W. Nathanielsz. Prenatal origins of adult disease. Curr Opin Obstet Gynecol. 2008 Apr;20(2):132-8. 3. M. Andersen, D. Belangery, R. Droumevaz, J. Li, G. Moss, G. Palauk. Quantifying clinically significant features of placental histology images: a method. Technical report, http://www.sfu.ca/~jlie/MITACS/Report.pdf 4. M. Yampolsky, O. Shlakhter, C. Salafia, D. Haas. Mean surface shape of a human placenta, e-print Arxiv.org, 0807.2995 5. M. Yampolsky, C. Salafia, O. Shlakhter, D. Haas, B. Eucker, J. Thorp. Modeling the variability of shapes of a human placenta, Placenta, 29(2008), 790 - 797. 6. C. Salafia, D. Misra, M. Yampolsky, A. Charles, R. Miller. Allometric metabolic scaling and fetal and placental weight, Placenta, in press. 7. C. Salafia, M. Yampolsky. Metabolic scaling law for fetus and placenta, Placenta, in press.
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