Ultrastructure of endothelial cells of fetal capillaries of placentae of women with pregnancy induced hypertension

The present study aimed to compare the ultra structural features of endothelial cells of fetal terminal capillaries of placentae from hypertensive (n=10) and non-hypertensive (n=10) pregnancies. The ultrastructural features of endothelial cells of terminal capillaries from the fetal surface of each placenta were examined under the electron microscope. Micrographs of 8 different endothelial cells from each placenta were-prepared for evaluation by stereological analysis using a coherent double lattice test system. The volume fractions of different organelles and cytosol in endothelial cells of placental fetal capillaries of both hypertensive and non-hypertensive pregnancies were deter­ mined by counting the number of grid intersection points falling on the endothelial cell cytoplasm, mitochondria, rough endoplasmic reticulum and glycogen deposits. Ultrastructural changes were noted in endothelial cells of capillaries of placentae of mothers with pregnancy induced hypertension. Statistical analysis showed that the volume fractions of the organelles and the amount of cytoplasm of endothelial cells of placentae from hypertensive pregnancies were significantly higher than those from non-hypertensive pregnancies. There was a significant increase in some of the organelles and the capacity of cytoplasm of endothelial cells of placentae from hypertensive pregnancies when compared to normotensive pregnancies. These findings may be attributed to compensatory mechanisms operating as a response to hypoxia caused by reduced maternal blood flow to the placenta.