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Expression of nitric oxide synthase in human trophoblast
A.54
Placenta (1993), Vol 14
THE ROLE OF PLACENTAL ANTIOXIDANT ENZYMES. H. Mover and A. Ar, Department of Zoology, Tel-Aviv University, TeI-Aviv 69978 Israel. Intra-uterine development of mammalian embryos depend on supply of nutrients, gas exchange, and excertion of waste products through the placenta. Does the placenta also protect the embryo against reactive oxygen species that may endanger embryonic development? Enzymatic activities (per mg protein) of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) were measured in placenta, embryos and adult tissues of rats. Activity at term of SOD, CAT and GPX in the placenta was one of the lowest found among the different tissues: 25% and 15-50% that of maternal liver and lungs respectively. SOD and CAT activities were similar to the non-pregnant uterus and GPx was 70% lower. At mid gestation, CAT activity was low in both the placenta and embryos: 20% and 30% of the activity at term respectively. SOD activity reached 73% and 62% its term values in placenta and and embryos respectively. GPx was 100% in placenta and 70% in embryos compared with term values. The antioxidant activity of the embryos at term was in the same range as the placenta but lower compared with parallel maternal tissues. It seems that the main protective role of these enzymes in the placenta is during early stages of pregnancy, when the placenta develops faster than the embryos. Near term, the mature embryo is capable of protecting itself by its owen increased tissue enzymatic activity. The placenta is a highly aerobic and metabolically active tissue. Antioxidant enzyme activity is necessary for its owen normal performance. Placental well-being is one of the prequisits for normal e m b r y o n i c development.
EXPRESSION OF NITRIC OXIDE SYNTHASE IN HUMAN TROPHOBLAST. L Myatt, DE Brockman, AW Eis, JS Pollock1. Dept. Ob/Gyn, University of Cincinnati College of Medicine, Cincinnati, OH 45267 and 1Abbott Laboratories, Abbott Park, IL 60064 USA. The vasodilator nitric oxide contributes to maintenance of basal vascular tone and attenuates the actions of vasoconstrictors in the human fetal-placental circulation. We have studied the expression of the constitutive endothelial isoform of nitric oxide synthase (eNOS) in the human fetal-placental unit and primary trophoblast cultures. Frozen sections from umbilical cord, chorionic plate vessels and terminal villi of normotensive term placentae were prepared. Cytotrophoblast was isolated from term placentae purified by percoll gradient centrifugation and immuno purification and cultured up to six days for syncytiotrophoblast formation before fixation. Endothelial NOS was localized by indirect immunofluorescent histochemistry with a monoclonal antibody H32 against the bovine aortic eNOS isoform which shows 94% homology with the human isoform, and FITC labelled 2nd antibody. Intense positive immunofluorescence for eNOS was found in umbilical cord artery and vein endothelium and in syncytiotrophoblast. Endothelial cells of chorionic plate and stem villous vessels were also immunopositive, whereas capillary endothelium of terminal villi which has no underlying smooth muscle, was not. No positive immunostaining was found in single cytotrophoblast cells in culture; however, following aggregation and fusion to syncytiotrophoblast, positive eNOS immunostaining became apparent. NOS expression in trophoblast appears to be related to cellular differentiation and may serve to produce nitric oxide which prevent platelet adhesion and aggregation in the intervillous space.
Placenta (1993), Vol 14
THE ROLE OF PLACENTAL ANTIOXIDANT ENZYMES. H. Mover and A. Ar, Department of Zoology, Tel-Aviv University, TeI-Aviv 69978 Israel. Intra-uterine development of mammalian embryos depend on supply of nutrients, gas exchange, and excertion of waste products through the placenta. Does the placenta also protect the embryo against reactive oxygen species that may endanger embryonic development? Enzymatic activities (per mg protein) of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) were measured in placenta, embryos and adult tissues of rats. Activity at term of SOD, CAT and GPX in the placenta was one of the lowest found among the different tissues: 25% and 15-50% that of maternal liver and lungs respectively. SOD and CAT activities were similar to the non-pregnant uterus and GPx was 70% lower. At mid gestation, CAT activity was low in both the placenta and embryos: 20% and 30% of the activity at term respectively. SOD activity reached 73% and 62% its term values in placenta and and embryos respectively. GPx was 100% in placenta and 70% in embryos compared with term values. The antioxidant activity of the embryos at term was in the same range as the placenta but lower compared with parallel maternal tissues. It seems that the main protective role of these enzymes in the placenta is during early stages of pregnancy, when the placenta develops faster than the embryos. Near term, the mature embryo is capable of protecting itself by its owen increased tissue enzymatic activity. The placenta is a highly aerobic and metabolically active tissue. Antioxidant enzyme activity is necessary for its owen normal performance. Placental well-being is one of the prequisits for normal e m b r y o n i c development.
EXPRESSION OF NITRIC OXIDE SYNTHASE IN HUMAN TROPHOBLAST. L Myatt, DE Brockman, AW Eis, JS Pollock1. Dept. Ob/Gyn, University of Cincinnati College of Medicine, Cincinnati, OH 45267 and 1Abbott Laboratories, Abbott Park, IL 60064 USA. The vasodilator nitric oxide contributes to maintenance of basal vascular tone and attenuates the actions of vasoconstrictors in the human fetal-placental circulation. We have studied the expression of the constitutive endothelial isoform of nitric oxide synthase (eNOS) in the human fetal-placental unit and primary trophoblast cultures. Frozen sections from umbilical cord, chorionic plate vessels and terminal villi of normotensive term placentae were prepared. Cytotrophoblast was isolated from term placentae purified by percoll gradient centrifugation and immuno purification and cultured up to six days for syncytiotrophoblast formation before fixation. Endothelial NOS was localized by indirect immunofluorescent histochemistry with a monoclonal antibody H32 against the bovine aortic eNOS isoform which shows 94% homology with the human isoform, and FITC labelled 2nd antibody. Intense positive immunofluorescence for eNOS was found in umbilical cord artery and vein endothelium and in syncytiotrophoblast. Endothelial cells of chorionic plate and stem villous vessels were also immunopositive, whereas capillary endothelium of terminal villi which has no underlying smooth muscle, was not. No positive immunostaining was found in single cytotrophoblast cells in culture; however, following aggregation and fusion to syncytiotrophoblast, positive eNOS immunostaining became apparent. NOS expression in trophoblast appears to be related to cellular differentiation and may serve to produce nitric oxide which prevent platelet adhesion and aggregation in the intervillous space.