Gabor Than Award Lecture 2006: Pre-Eclampsia and Villous Trophoblast Turnover: Perspectives and Possibilities

Diagram of cell turnover of the villous trophoblast. Proliferation of stem cell cytotrophoblasts is followed by the induction of early stages of apoptosis culminating in the dissolution of their plasma membrane, fusion and incorporation into the overlying syncytiotrophoblast. Apoptotic progression leads to the accumulation of condensed nuclei into syncytial knots and the shedding of these aggregates into the intervillous spaces. CT, cytotrophoblast; FC, fetal capillary; IVS, intervillous space; MVM, microvillous membrane; SKT, syncytial knot; ST, syncytiotrophoblast. Diagram kindly provided by Dr Carolyn Jones of the Division of Human Development, University of Manchester, UK.

Morphometric analysis of the villous placenta in pre-eclampsia. (A–C) Image manipulations of placental sections. (A) Monochrome image of villous tissue. (B) Image is pseudocoloured using morphometric software. (C) A threshold is applied (red background) and increased sequentially to highlight the syncytiotrophoblast. (D) Pre-eclampsia alone (PE) and pre-eclampsia with superimposed growth restriction (PE x IUGR) showing a reduction in syncytiotrophoblast, corrected for villous area. Idiopathic IUGR had no effect. (E) Irrespective of placental weight, syncytiotrophoblast cover was significantly correlated with birthweight. (Modified from Daayana et al. [66]; reproduced by kind permission of Elsevier Inc.)

Schematic showing the generation of intervillous haemodynamic velocities and turbulences. (A) A reduction in internal luminal diameter (or radius, r) leads to a disproportionate increase in flow velocity (v) under constant flow. (B) The potential outcome of adequate and inadequate transformations of uterine spiral arteries in normal pregnancy and pre-eclampsia. Intra-luminal obstructions such as atherosclerotic plaques may further exaggerate disruptive blood flow entering the intervillous space.