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A morphometric study of the placenta in pregnancy complicated by insulin-dependent diabetes mellitus
Abstracts: European Placenta Group~Rochester Trophoblast Joint Conference
487
A MORPHOMETRIC STUDY OF THE PLACENTA IN PREGNANCY COMPLICATED BY INSULIN-DEPENDENT DIABETES MELLITUS A. O. Fabamwo, B. L. Sheppard & R. F. Harrison (University College Hospital, Ibadan, Nigeria) In this study, the zonal morphological variations in the horizontal and vertical planes of placentae in term deliveries of diabetic and non-diabetic mothers were investigated. Comparisons of gross microscopic components of parenchyma and non-parenchyma were made in placentae from five non-diabetic pregnancies and Io diabetic pregnancies resulting in five appropriate (AGA) and five large (LGA) for gestational age babies. Ten MSB stained slides were examined from five full-thickness blocks from each placenta. One hundred counts were made for points falling on villous trophoblast, villous fetal capillaries, intervillous space, fibrin, syncytial knots and villous stroma in each of five fields from the parabasal to the subchorionic surface. The results showed that the human placenta comprises regions in the horizontal and vertical planes, with statistically significant differences in distribution of parenchymal and nonparenchymal components. The zonal distribution of parenchymal components affirms the relative importance of the core of the parabasal surface as the site of feto-maternal exchange, and the distribution of fibrin and syncytial knots suggests that the peripheral and subchorionic regions of the placenta are characterized by reduced uteroplacental blood flow and oxygen content. There was no evidence that the presence of maternal diabetes mellitus disrupts this orderly pattern. The placentae from LGA infants were heavier than the others, owing principally to accumulation of non-parenchymal tissue. Placentae from AGA babies had higher proportions of functional parenchyma and microscopic parenchymal components, a betterdeveloped vascularization and an increased response to relative hypoxia than placentae from LGA babies, the latter being able to sustain the growth of the fetus presumably by a relative increase in the functional efficiency of the parenchymal components. There was morphometric evidence of reduced uteroplacental blood flow and relative hypoxia in placentae from diabetic pregnancies. Lack of correlation between maternal blood glucose values and most of the functional morphometric parameters provides evidence for the less important role of maternal glycaemia in altered feto-placental growth in diabetic pregnancies.
GIANT CELLS OF THE PLACENTAL BED MYOMETRIUM IN LATE PREGNANCY B. L. Sheppard & J. Bonnar (St James's Hospital, Dublin, Ireland) Positive identification of a biopsy being taken from the placental bed is based on the presence of interstitial, multinucleate 'giant' trophoblast cells within the myometrium. The need to identify these cells readily has become increasingly important following the recent observations concerning the possible failure o f uteroplacental vessels to undergo complete physiological adaptations in certain complications of pregnancy. In this study, the structure of placental bed giant cells was examined in biopsies taken at caesarean section. The depth of invasion into the myometrium and the distribution of these trophoblast cells from the centre to the periphery of the placental bed were studied in uteri obtained at caesarean hysterectomy. The trophoblast cells were seen interspersed between smooth muscle cells of the myometrium. The multinucleate giant cells contained a cytoplasm rich in rough cisternal endoplasmic reticulum, large mitochondria and fine fibrils. Desmosomes and plasma membrane fragments were often evident within the cytoplasm. The outer cell membrane was very irregular and was often surrounded by a secretory granular material. In the centre of the placental bed, the depth of
487
A MORPHOMETRIC STUDY OF THE PLACENTA IN PREGNANCY COMPLICATED BY INSULIN-DEPENDENT DIABETES MELLITUS A. O. Fabamwo, B. L. Sheppard & R. F. Harrison (University College Hospital, Ibadan, Nigeria) In this study, the zonal morphological variations in the horizontal and vertical planes of placentae in term deliveries of diabetic and non-diabetic mothers were investigated. Comparisons of gross microscopic components of parenchyma and non-parenchyma were made in placentae from five non-diabetic pregnancies and Io diabetic pregnancies resulting in five appropriate (AGA) and five large (LGA) for gestational age babies. Ten MSB stained slides were examined from five full-thickness blocks from each placenta. One hundred counts were made for points falling on villous trophoblast, villous fetal capillaries, intervillous space, fibrin, syncytial knots and villous stroma in each of five fields from the parabasal to the subchorionic surface. The results showed that the human placenta comprises regions in the horizontal and vertical planes, with statistically significant differences in distribution of parenchymal and nonparenchymal components. The zonal distribution of parenchymal components affirms the relative importance of the core of the parabasal surface as the site of feto-maternal exchange, and the distribution of fibrin and syncytial knots suggests that the peripheral and subchorionic regions of the placenta are characterized by reduced uteroplacental blood flow and oxygen content. There was no evidence that the presence of maternal diabetes mellitus disrupts this orderly pattern. The placentae from LGA infants were heavier than the others, owing principally to accumulation of non-parenchymal tissue. Placentae from AGA babies had higher proportions of functional parenchyma and microscopic parenchymal components, a betterdeveloped vascularization and an increased response to relative hypoxia than placentae from LGA babies, the latter being able to sustain the growth of the fetus presumably by a relative increase in the functional efficiency of the parenchymal components. There was morphometric evidence of reduced uteroplacental blood flow and relative hypoxia in placentae from diabetic pregnancies. Lack of correlation between maternal blood glucose values and most of the functional morphometric parameters provides evidence for the less important role of maternal glycaemia in altered feto-placental growth in diabetic pregnancies.
GIANT CELLS OF THE PLACENTAL BED MYOMETRIUM IN LATE PREGNANCY B. L. Sheppard & J. Bonnar (St James's Hospital, Dublin, Ireland) Positive identification of a biopsy being taken from the placental bed is based on the presence of interstitial, multinucleate 'giant' trophoblast cells within the myometrium. The need to identify these cells readily has become increasingly important following the recent observations concerning the possible failure o f uteroplacental vessels to undergo complete physiological adaptations in certain complications of pregnancy. In this study, the structure of placental bed giant cells was examined in biopsies taken at caesarean section. The depth of invasion into the myometrium and the distribution of these trophoblast cells from the centre to the periphery of the placental bed were studied in uteri obtained at caesarean hysterectomy. The trophoblast cells were seen interspersed between smooth muscle cells of the myometrium. The multinucleate giant cells contained a cytoplasm rich in rough cisternal endoplasmic reticulum, large mitochondria and fine fibrils. Desmosomes and plasma membrane fragments were often evident within the cytoplasm. The outer cell membrane was very irregular and was often surrounded by a secretory granular material. In the centre of the placental bed, the depth of