Effects of Hyperglycemia on Angiogenesis in Human Placental Endothelial Cells.

The placenta is a temporary organ that provides communication between the mother and fetus. Maternal diabetes and abnormal placental angiogenesis may be linked. We investigated the angiogenesis mechanism resulting from VEGF and glucose stimulation in PECs obtained from human term placenta. Immunohistochemistry was performed to characterize PECs obtained from human term placenta. D-glucose was added to the medium containing PECs to establish normoglycemic and hyperglycemic conditions. The expression levels of VEGF, VEGFR-1 and VEGFR-2 genes and proteins in PECs from the control and experimental groups were analyzed by RT-PCR and Western blotting, respectively. With 48-hours incubation, gene expressions increased due to hyperglycemia, while protein levels increased due to the combined effect of VEGF and hyperglycemia. While VEGFR-2 gene expression and protein amounts increased in 24-hours due to the combined effect of VEGF and hyperglycemia, the effect of VEGF stimulation and glucose level on VEGFR-2 decreased in 48-hour incubation with time. VEGF, VEGFR-1 and VEGFR-2 genes and proteins were affected by hyperglycemic conditions in PECs. Hyperglycemia occurring in various conditions such as gestational diabetes mellitus and diabetes mellitus may affect VEGF, VEGFR-1 and VEGFR-2 genes and proteins of PECs derived from human term placenta.

Are innate lymphoid cells friend or foe in human pregnancy?

Innate lymphoid cells (ILCs) are involved in the innate immune system because they lack specific antigen receptors and lineage markers. ILCs also display phenotypic and characteristic features of adaptive immune cells. Therefore, ILCs are functional in essential interactions between adaptive and innate immunity. ILCs are found in both lymphoid and nonlymphoid tissues and migrate to the area of inflammation during the inflammatory process. ILCs respond to pathogens by producing a variety of cytokines and are involved in the barrier defense of antigens and in many immunological processes such as allergic events. Recent research has shown that ILCs are functional during human pregnancy and have been suggested to be essential for the healthy progression of pregnancy. In this review, we focus on the role of ILCs in human pregnancy by discussing the relationship between ILCs and the pregnancy microenvironment, specifically summarizing the role of ILCs in physiological and pathological pregnancies.

Effects of Stevioside on the Expressions of GLUT 1, GLUT 3, and GLUT 4 Proteins in Diabetic Rat Placenta.

The placenta provides maternal-fetal nutrient transport. The primary source of energy for fetus development is glucose and maternal-fetal glucose transport occurs through glucose transporters (GLUTs). Stevioside, a component of Stevia rebaudiana Bertoni, is used for medicinal and commercial purposes. We aim to determine the effects of stevioside on GLUT 1, GLUT 3, and GLUT 4 proteins expressions in diabetic rat placentas. The rats are divided into four groups. A single dose of streptozotocin (STZ) is administered to form the diabetic groups. Pregnant rats receive stevioside to form the stevioside and diabetic + stevioside groups. According to immunohistochemistry results, GLUT 1 protein is found in both the labyrinth and junctional zones. GLUT 3 protein is limited in the labyrinth zone. GLUT 4 protein is detected in trophoblast cells. According to Western blotting results, on the 15th and 20th days of pregnancy, there is no difference in the expression of GLUT 1 protein between groups. On the 20th day of pregnancy, the expression of GLUT 3 protein in the diabetic group is statistically higher compared to the control group. On the 15th day and 20th day of pregnancy, the expression of GLUT 4 protein in the diabetic group is statistically lower compared to the control group. Insulin levels in blood samples derived from rat abdominal aorta are determined by the ELISA method. According to the ELISA results, there is no difference in insulin protein concentration between groups. Stevioside treatment reduces GLUT 1 protein expression under diabetic conditions.

Human placental trophoblast progenitor cells (hTPCs) promote angiogenesis and neurogenesis after focal cerebral ischemia in rats.

INTRODUCTION: Reduction of blood flow below a threshold value in brain regions locally or globally is called cerebral ischemia and proper treatment requires either the restoration of normal blood flow and/or the administration of neuroprotective therapies. Human trophoblast progenitor cells (hTPCs) give rise to the placenta and are responsible for the invasion and vascular remodeling of the maternal vessels within the uterus. Here, we tested whether hTPCs promoted to differentiate along neural lineages may exhibit therapeutic properties in the setting of cerebral ischemia in vivo. MATERIALS AND METHODS: Cerebral ischemia was generated in rats via middle cerebral artery occlusion and, after 24 h, hTPCs were injected systemically via tail vein. Animals were sacrified at Day 3 or 11. RESULTS: TTC staining indicated that infarct volumes were smaller in hTPC treated animals. Visible myelin recovery was observed in the hTPC injected group with Luxol Fast Blue staining. On Day 11 after hTPC transplantation, DLX5 and VEGF expression, as well as 2 and 10 d after hTPC transplantation, NKX2.2 were significantly increased; while LHX6, Olig1, PDGFRα, VEGFR1 and VEGFR2 showed trends toward improved expression in brain tissue via immunoblot analysis. Neuron-like differentiated cells were positive for both NeuN and Cresyl Violet staining. CONCLUSION: Here, we demonstrate for the first time that hTPCs enhance the expression of angiogenic and neurogenic factors in rat brain after stroke. Transplantation of hTPCs could form the basis of novel therapeutic approaches for the treatment of stroke in the clinical setting.

Contribution of Human Trophoblast Progenitor Cells to Neurogenesis in Rat Focal Cerebral Ischemia Model.

OBJECTIVE: : A decrease in the blood flow below a current level in the brain results in ischemia. Studies demonstrated that human trophoblast progenitor cells (hTPCs) contribute to the treatment of many diseases. Therefore, hTPCs might be a promising source to repair ischemia in cerebral ischemia models. For this purpose, we evaluated the expression of many neurogenesis markers by performing hTPC transplantation after focal cerebral ischemia in rats. METHODS: : hTPCs, isolated from the term placentae, were characterized by immunofluorescent staining and differentiated into neuron-like cells. Differentiation was confirmed with immunostaining of GFAP and NeuN proteins. Cerebral ischemia models were generated in rats via middle cerebral artery occlusion and, after 24 hours, hTPCs were injected via the tail vein. Animals were sacrificed on day 3 or day 11. Immunohistochemical analysis was performed with proteins associated with neurogenesis and neuronal development, such as DLX2, DLX5, LHX6, NGN1, and NGN2, Olig1, Olig2, and PDGFRα. RESULTS: : According to our results, hTPCs may alleviate ischemic damage in the brain and contribute to the neurogenesis after ischemia. CONCLUSIONS: : Based on our findings, this topic should be further investigated as the hTPC-based therapies may be a reliable source that can be used in the treatment of stroke and ischemia.

Does fresh or frozen embryo transfer affect imprinted gene expressions in human term placenta?

Our research aimed to compare the epigenetic alterations between placentae of in vitro fertilization (IVF) patients and spontaneous pregnancies. Additionally, the expression levels of proliferation markers (PCNA, Ki67) and glucose transporter proteins (GLUT1, GLUT3) were assessed in control and IVF placentae to examine the possible consequences of epigenetic alterations on placental development. Control group placentae were obtained from spontaneous pregnancies of healthy women (n = 16). IVF placentae were obtained from fresh (n = 16) and frozen (n = 16) embryo transfer pregnancies. A group of maternal and paternal imprint genes H19, IGF2, IGF2, IGF2R, PHLDA2, PLAGL1, MASH2, GRB10, PEG1, PEG3, and PEG10 were detected by Real-Time PCR. Additionally, PCNA, Ki67, GLUT1, and GLUT3 protein levels were assessed by immunohistochemistry and western blot. In the fresh embryo transfer placenta group (fETP), gene expression of paternal PEG1 and PEG10 was upregulated compared with the control group. Increased gene expression in paternal PEG1 and maternal IGFR2 genes was detected in the frozen embryo transfer placenta group (FET) compared with the control group. Conversely, expression levels of H19 and IGF2 genes were downregulated in the FET group. On the other hand, GLUT3 and PCNA expression was increased in FET group placentae. IVF techniques affect placental imprinted gene expressions which are important for proper placental development. Imprinted genes are differently expressed in fresh ET placentae and frozen ET placentae. In conclusion, these data indicate that altered imprinted gene expression may affect glucose transport and cell proliferation, therefore play an important role in placental development.

Effects of amnion derived mesenchymal stem cells on fibrosis in a 5/6 nephrectomy model in rats.

Chronic kidney disease (CKD) is characterized by disruption of the glomerulus, tubule and vascular structures by renal fibrosis. Mesenchymal stem cells (MSC) ameliorate CKD. We investigated the effects of human amnion derived MSC (hAMSC) on fibrosis using expression of transforming growth factor beta (TGF-ß), collagen type I (COL-1) and bone morphogenetic protein (BMP-7). We also investigated levels of urinary creatinine and nitrogen in CKD. We used a 5/6 nephrectomy (5/6 Nx) induced CKD model. We used 36 rats in six groups of six animals: sham group, 5/6 Nx group, 15 days after 5/6 Nx (5/6 Nx + 15) group, 30 days after 5/6 Nx (5/6 Nx + 30) group, transfer of hAMSC 15 days after 5/6 Nx (5/6 Nx + hAMSC + 15) group and transfer of hAMSC 30 days after 5/6 Nx (5/6 Nx + hAMSC + 30) group. We isolated 106 hAMSC from the amnion and transplanted them via the rat tail vein into the 5/6 Nx + hAMSC + 15 and 5/6 Nx + hAMSC + 30 groups. We measured the expression of BMP-7, COL-1 and TGF-ß using western blot and immunohistochemistry, and their gene expressions were analyzed by quantitative real time PCR. TGF-ß and COL-1 protein, and gene expressions were increased in the 5/6 Nx +30 group compared to the 5/6 Nx + hAMSC + 30 group. Conversely, both protein and gene expression of BMP-7 was increased in 5/6 Nx + hAMSC + 30 group compared to the 5/6 Nx groups. Increased TGF-ß together with decreased BMP-7 expression may cause fibrosis by epithelial-mesenchymal transition due to chronic renal injury. Increased COL-1 levels cause accumulation of extracellular matrix in CKD. Levels of urea, creatinine and nitrogen were increased significantly in 5/6 Nx + 15 and 5/6 Nx + 30 groups compared to the hAMSC groups. We found that hAMSC ameliorate CKD.

Effects of Human Placental Amnion Derived Mesenchymal Stem Cells on Proliferation and Apoptosis Mechanisms in Chronic Kidney Disease in the Rat.

BACKGROUND AND OBJECTIVES: The feature of chronic kidney failure (CKF) is loss of kidney functions due to erosion of healthy tissue and fibrosis. Recent studies showed that Mesenchymal stem cells (MSCs) differentiated into tubular epithelial cells thus renal function and structures renewed.Furthermore, MSCs protect renal function in CKF. Therefore, we aimed to investigate whether human amnion-derived mesenchymal stem cells (hAMSCs) can repair fibrosis and determine the effects on proliferation and apoptosis mechanisms in chronic kidney failure. METHODS AND RESULTS: In this study, rat model of CKF was constituted by applying Aristolochic acid (AA). hAMSCs were isolated from term placenta amnion membrane and transplanted into tail vein of rats. At the end of 30 days and 60 days of recovery period, we examined expressions of PCNA, p57 and Parp-1 by western blotting. Immunoreactivity of PCNA, Ki67, IL-6 and Collagen type I were detected by immunohistochemistry. Besides, apoptosis was detected by TUNEL. Serum creatinine and urea were measured. Expressions of PCNA and Ki67 increased in hAMSC groups compared with AA group. Furthermore, expressions of PARP-1 apoptosis marker and p57 cell cycle inhibitory protein increased in AA group significantly according to control, hAMSC groups and sham groups. IL-6 proinflammatory cytokine increased in AA group significantly according to control, hAMSCs groups and sham groups. Expressions of Collagen type I protein reduced in hAMSCs groups compared to AA group. After hAMSC treatment, serum creatinine and urea levels significantly decreased compared to AA group. After injection of hAMSC to rats, Masson’s Trichrome and Sirius Red staining showed fibrosis reduction in kidney. CONCLUSIONS: According to our results hAMSCs can be ameliorate renal failure.

Rapamycin administration during normal and diabetic pregnancy effects the mTOR and angiogenesis signaling in the rat placenta.

OBJECTIVE: The mammalian target of rapamycin (mTOR) signaling pathway has newly been recommended to be a nutrient sensor in the placenta. It is speculated that mTORC1 may be activated in diabetes, associated with increased placental nutrient availability. Thus, we aimed to investigate the mTOR signaling pathway both in diabetic and non-diabetic placenta and searched for the alterations of angiogenic factors VEGF, VEGFR1 and VEGFR2. METHODS: Streptozotocin (STZ) was administered by intravenous injection in doses of 60 mg/kg body weight and STZ injected rats were exposed to Everolimus (Rapamycin analog) and sacrificed at gestational days 14 and 20. mTORC1 and mTORC2 target proteins and angiogenic factors were analyzed at protein and mRNA levels in the placenta. Soluble VEGF A and Insulin protein levels were determined in blood serum. RESULTS: Placenta and embryo weights were altered after STZ and/or Rapamycin administration. mTOR pathway inhibition was confirmed by decreased p70S6K (Thr389) phosphorylation levels. We found that maternal diabetic environment led to an increase in Akt phosphorylation at 14th and decrease at 20th gestational days. Serum levels of Insulin in 14 th and 20 th days of gestation were decreased in Rapamycin and diabetic groups. On the other side serum levels of Soluble VEGF were increased in 14 th and decreased in 20 th days of pregnancy. CONCLUSION: According to our results, it might be suggested that angiogenesis related proteins will be related with placental growth regulation and mTOR may be a candidate pathway mediating the process in normal and diabetic pregnancy.

Effect of glucocorticoids on mechanisms of placental angiogenesis.

The benefits of antenatal glucocorticoid (GC) treatment to promote human fetal lung maturation are well established. However, reports have emerged indicating that maternal exposure to high concentrations of circulating GCs alters placental and fetal development. Because many adult-onset metabolic and cardiovascular disorders have their origins in utero, the importance of prenatal conditions should be considered in detail. Therefore, this review aims to present an overview of the GC effect on placental and fetal development, specifically with regard to mechanisms of placental angiogenesis. We assumed that GC overexposure affects fetal development by altering placental angiogenesis. Disturbances in the development of the villous tree and pathological changes in the villous vascular system with insufficient uteroplacental blood flow have been linked to the pathogenesis of intrauterine growth retardation. Moreover, low birth weight is a serious risk factor known to correlate with an increased risk of adult-onset diseases. Although there have been many circumstances in which maternal GCs are elevated, we focused on exogenous synthetic GCs that are applied for therapeutic reasons. However, some questions about the use of steroids remain unanswered, which will require further studies that lead us to review alterations in placental angiogenesis under the perspective of GC overexposure.

Determination of PCNA, cyclin D3, p27, p57 and apoptosis rate in normal and dexamethasone-induced intrauterine growth restricted rat placentas.

Intrauterine growth restriction (IUGR) is a major clinical problem, which causes perinatal morbidity and mortality. One of the reasons for IUGR is abnormal placentation. In rats, fetal-placental exposure to maternally administered glucocorticoids decreases birth weight and placental weight. Proper placental development depends on the proliferation and differentiation of trophoblasts. Our knowledge about the mitotic regulators that play key roles in synchronizing these events is limited. Also the mechanisms underlying the placental growth inhibitory effects of glucocorticoids have not been elucidated. The aim of this study was to investigate the immunolocalization, mRNA and protein levels of proliferating cell nuclear antigen (PCNA), cyclin D3, p27 and p57 in normal and dexamethasone-induced IUGR Wistar rat placentas by reverse transcriptase polymerase chain reaction (RT-PCR), immunohistochemistry and Western blot. We also compared apoptotic cell numbers at the light microscopic level via terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling (TUNEL) and transmission electron microscopy. Glucocorticoid levels were higher in IUGR rats than in control rats after 60 and 120min of injection. We showed reduced gene and protein expressions of PCNA and cyclin D3 and increased expressions of p27 and p57 in IUGR placentas compared to control placentas. Apoptotic cell number was higher in the placentas of the IUGR group. In brief we found that maternal dexamethasone treatment led to a shift from cell proliferation to apoptosis in IUGR placentas. Dexamethasone induced placental and embryonal abnormalities which could be associated with reduced expressions of PCNA and cyclin D3, increased expressions of p27 and p57 and increased rate of apoptosis in IUGR placentas.

Glucocorticoid exposure altered angiogenic factor expression via Akt/mTOR pathway in rat placenta.

During pregnancy, glucocorticoids (GCs) are used for fetal lung maturation in women at risk of preterm labor. Exogenous GCs do not have exclusively beneficial effects and repeated use of GCs remains controversial. It has been observed that GC exposed rats have smaller placentas and intrauterine growth retarded fetuses. In this study, we questioned whether or not glucocorticoids effect placental angiogenesis mechanisms. One of the most important signaling pathways among several downstream of VEGFR-2 is PI3K/Akt which subsequently activates the mammalian target of rapamycin. Therefore, we hypothesized that overexposure to GCs may adversely affect placental angiogenesis mechanisms by regulating pro-angiogenic factors and their receptors via Akt/mTOR pathway. According to our results Dexamethasone, a synthetic glucocorticoid, administration led to a decrease in VEGF, PIGF expression during pregnancy. VEGFR2 expression was first decreased at gestational day 14 and afterwards increased at gestational days 16, 18 and 20 in rat placentas. These results are in accordance with the reduced phosphorylation of Akt, 4EBP1 and p70S6K. Dexamethasone injection also resulted in a reduction of VEGF, VEGFR1, and VEGFR2 mRNA expression at gestational days 14 and 20, but PIGF mRNA expression was not altered. Growth retarded fetuses seen in Dexamethasone treated pregnancies, may be a result of altered angiogenic factor expression of the placenta mediated via altered mTOR pathway signaling.

The expression of cell cycle related proteins PCNA, Ki67, p27 and p57 in normal and preeclamptic human placentas.

Placenta is a transitional area making many physiological activities between mother and fetus and therefore, it is a critical organ influencing the outcome of pregnancy. Fetal growth is directly related to placental development. Accurate placental development depends on coordinated action of trophoblasts' proliferation, differentiation and invasion. Information on cell cycle related proteins that control these events is limited and how they are affected in preeclampsia is not fully understood yet. Therefore, in this study, in order to understand the role of cell cycle regulators in preeclamptic placentas we aimed to determine the spatio-temporal immunolocalizations of cell cycle regulators in preeclamptic and normal human term placentas. Term placentas were obtained from women diagnosed with preeclampsia and from normal pregnancies with informed consent following cesarean deliveries. Placental samples were stained via immunohistochemistry with PCNA, Ki67, p27, p57, vimentin and cytokeratin 7 antibodies and were examined by light microscopy. PCNA and Ki67 staining intensities significantly increased in villous parts, significantly decreased in basal plates of PE group and did not change in chorionic plates. Staining intensities of cell cycle inhibitors p27 and p57 significantly increased in all parts of preeclamptic placentas compared to control. Placental abnormalities of preeclamptic placentas might be associated with proliferation and cell cycle arrest mechanisms' alterations occurred in preeclampsia.

Immunolocalization of cell cycle proteins (p57, p27, cyclin D3, PCNA and Ki67) in intrauterine growth retardation (IUGR) and normal human term placentas.

Placental development involves a series of events that depend on the coordinated action of proliferation, differentiation and invasion of trophoblasts. Studies on cell cycle related proteins controlling these events are fairly limited. It is still not fully determined how placental tissue proliferation is affected by intrauterine growth retardation (IUGR). Information on cell cycle related proteins that control these events is limited and how they are affected in IUGR is not fully understood. The aim of this study was to understand the role of cell cycle regulators in IUGR placentas and to determine the spatio-temporal immunolocalization of these cell cycle regulators in human IUGR and normal term placentas. Placental samples were stained immunohistochemically with PCNA, Ki67, cyclin D3, p27 and p57 antibodies and were examined by light microscopy. In all regions of IUGR placentas, PCNA, Ki67 and cyclin D3 staining intensities were statistically significantly decreased compared to normal controls. p27 staining intensity of the IUGR group was statistically significantly increased in villous parts and chorionic plates in comparison with the normal term placentas. Moreover, p57 staining intensity was statistically significantly increased in all parts of the IUGR group compared to controls. The observed placental abnormalities in IUGR placentas may be associated with arrest mechanisms affecting cell proliferation and cell cycle alterations in IUGR.

Immunohistochemical distribution of cell cycle proteins p27, p57, cyclin D3, PCNA and Ki67 in normal and diabetic human placentas.

The placenta is a regulator organ for many metabolic activities between mother and fetus. Therefore, fetal growth is directly related to the placental development. Placental development is a series of events that depend on the coordinated action of trophoblasts' proliferation, differentiation and invasion. Studies on cell cycle related proteins which control these events are fairly limited. How placental tissue proliferation is affected by diabetes is not exactly known yet. Therefore in this study, the immunohistochemical localizations of cell cycle related proteins like PCNA, Ki67, cyclin D3, p27 and p57 in the differentiation, proliferation and apoptosis mechanisms of normal and diabetic placentas were investigated. Information on cell cycle related proteins that control these events is limited and how they are affected in diabetes mellitus is not fully understood yet. Therefore, in this study, to understand the role of cell cycle regulators in diabetic placentas we aimed to determine the spatio-temporal immunolocalizations of cell cycle regulators in diabetic and normal human term placentas. Term placentas were obtained from diabetic women and from normal pregnancies with informed consent following caesarean deliveries. Placental samples were stained via immunohistochemistry with PCNA, Ki67, cyclin D3, p27 and p57 antibodies and were examined by light microscopy. When compared to control placentas, PCNA, Ki67 and cyclin D3 staining intensities significantly increased in villous parts of diabetes group. Moreover, Ki67 and cyclin D3 stainings also significantly increased in basal plates and chorionic plate respectively. In chorionic plates, p27 and p57 staining intensities significantly decreased in diabetic group. p57 staining also significantly decreased in villous parts of diabetic placentas. Placental abnormalities seen in diabetic placentas could be associated with proliferation and cell cycle arrest mechanisms' alterations occurred in diabetes mellitus.

The PI3K/Akt and MAPK-ERK1/2 pathways are altered in STZ induced diabetic rat placentas.

Diabetic pregnancy is associated with complications such as early and late embryonic death, fetal growth disorders, placental abnormalities, and embryonal-placental metabolic disorders. Excessive apoptosis and/or changes of proliferation mechanisms are seen as a major event in the pathogenesis of diabetes-induced embryonic death, placental weight and structural anomalies. Akt and ERK1/2 proteins are important for placental and fetal development associated with cellular proliferation and differentiation mechanisms. The mechanism underlying the placental growth regulatory effects of hyperglycemia have not been elucidated. Moreover, it is still not determined how Akt and ERK1/2 proteins related proliferation and apoptosis mechanisms are influenced by Streptozotocin (STZ) induced diabetic rat placental development. The aim of this study was to investigate the expression levels and spatio-temporal immunolocalizations of Akt, p-Akt, ERK1/2 and p-ERK1/2 proteins in normal and STZ-treated diabetic rat placental development. In order to compose the diabetic group, pregnant females were injected with a single dose of 40 mg/kg STZ intraperitonally seven days before their sacrifice at 12th, 14th, 16th, 18th and 20th day of their gestation. We found that maternal diabetic environment led to a decrease in ERK1/2 and Akt phosphorylation during rat placental development. It could be said that MAPK-ERK1/2 and PI3K/Akt cell signaling pathways are affected from hyperglycemic conditions in rat placentas. In conclusion, hyperglycemia-induced placental and embryonal developmental abnormalities could be associated with reduction of Akt and ERK1/2 phosphorylation.

Location of proliferating cell nuclear antigen and p53 protein in human first trimester and term placenta.

OBJECTIVE: To examine immunohistochemically the distribution of cell-cycle regulators p53 and proliferating cell nuclear antigen (PCNA), which are in close cooperation with each other in first trimester and term human placentas. STUDY DESIGN: Human first trimester placental tissue was obtained by curettage from legal abortions obtained for social reasons, and human term placental tissue was obtained. Neither the interrupted pregnancy nor the obstetrical history showed any abnormalities. A total of 12 tissue samples were analyzed: n = 6 (6-12 weeks), n = 6 (38-40 weeks). Tissues were evaluated by immunohistochemical study. RESULTS: In the first trimester p53 expression was at a normal level, and p53 immunolabeling was present in syncytiotrophoblast and extravillous trophoblast cells found in the cell column. Very few villous stroma cells were p53 positive. PCNA was present intensely in the cytotrophoblast and in extravillous trophoblast found in the cell column. In term placentas p53 immunolabeling was very low and was expressed in only a limited number of syncytiotrophoblast cells. PCNA was at a normal level in villous and extravillous tissue. PCNA was decreased when compared with the first trimester and was present in syncytiotrophoblast and cytotrophoblast cells. A small number of endothelial cells and villous stromal cells were positive. CONCLUSION: We think that the immunohistochemical distribution of PCNA and p53 are strongly coordinated with each other in villous and extravillous cells in human placenta. This finding may be useful in the explanation of placental pathologies.

Triamcinolone up-regulates GLUT 1 and GLUT 3 expression in cultured human placental endothelial cells.

The placenta is a glucocorticoid target organ, and glucocorticoids (GCs) are essential for the development and maturation of fetal organs. They are widely used for treatment of a variety of diseases during pregnancy. In various tissues, GCs have regulated by glucose transport systems; however, their effects on glucose transporters in the human placental endothelial cells (HPECs) are unknown. In the present study, HPECs were cultured 24 h in the presence or absence of 0.5, 5 and 50 µmol · l(-1) of synthetic GC triamcinolone (TA). The glucose carrier proteins GLUT 1, GLUT 3 and GC receptor (GR) were detected in the HPECs. We showed increased expression of GLUT 1 and GLUT 3 proteins and messenger RNA (mRNA) levels (p < 0.05) after 24-h cell culture in the presence of 0.5, 5 and 50 µmol · l(-1) of TA. In contrast, GR protein and mRNA expressions were down-regulated (p < 0.05) with 0.5, 5 and 50 µmol · l(-1) of TA 24-h cell culture. The results demonstrate that GCs are potent regulators of placental GLUT 1 and GLUT 3 expression through GR. Excessive exposure to GCs causes maternal and fetal hypoglycemia and diminished fetal growth. We speculate that to compensate for fetal hypoglycemia and diminished fetal growth, the expression of placental endothelial glucose transporters might be increased.

Immunolocalization of PCNA, Ki67, p27 and p57 in normal and dexamethasone-induced intrauterine growth restriction placental development in rat.

Intrauterine growth restriction (IUGR) is a major clinical problem which causes perinatal morbidity and mortality. Although fetuses with IUGR form a heterogeneous group, a major etiological factor is abnormal placentation. Despite the fact that placental development requires the coordinated action of trophoblast proliferation and differentiation, there are few studies on cell cycle regulators, which play the main roles in the coordination of these events. Moreover it is still not determined how mechanisms of coordination of proliferation and differentiation are influenced by dexamethasone-induced IUGR in the placenta. The aim of the study was to investigate the spatial and temporal immunolocalization of proliferating cell nuclear antigen (PCNA), Ki67, p27 and p57 in normal and IUGR placental development in pregnant Wistar rats. The study demonstrated altered expressions of distinct cell cycle proteins and cyclin dependent kinase inhibitors (CKIs) in IUGR placental development compared to control placental development. We found reduced immunostaining of PCNA and Ki67 and increased immunostaining of p27 and p57 in the dexamethasone-induced IUGR placental development compared to control placental development. In conclusion, our data show that the cell populations in the placenta stain for a number of cell cycle related proteins and that these staining patterns change as a function of both gestational age and abnormal placentation.

Expression of glucocorticoid receptor and glucose transporter-1 during placental development in the diabetic rat.

In various tissues, glucocorticoids (GCs) are known to downregulate glucose transport systems; however, their effects on glucose transporters (GLUTs) in the placenta of a diabetic rat are unknown. Glucocorticoid hormone action within the cell is regulated by the glucocorticoid receptor (GR). Thus, this study was designed to investigate the relationship between GR and glucose transporter expression in the placenta of the diabetic rat. Our immunohistochemical results indicated that GR and glucose transporter protein 1 (GLUT 1) are expressed ubiquitously in the trophoblast and endothelial cells of the labyrinthine zone, where maternal fetal transport takes place in the rat placenta. Expression of GR in the junctional zone of the rat placenta was detected in giant cells, and in some spongiotrophoblast cells, but not in the glycogen cells. GLUT 1 was present, especially in glycogen cells during early pregnancy, and in the spongiotrophoblast cells of the junctional zone during late pregnancy. Amounts of GR and GLUT 1 protein were increased towards the end of gestation both in the control and the diabetic placenta. However, at days 17 and 19 of gestation, only the placental GR protein was significantly increased in the streptozotocin-induced diabetic rats compared to control rats. Diabetes led to a significant decrease in placental weight at gestation day 15. In contrast, at gestational days 17 and 21, the weights of the diabetic placenta were significantly increased as compared with the controls. Moreover, diabetes induced fetus intrauterine growth retardation at gestational days 13, 17 and 21. In conclusion, the localization pattern of GR and GLUT 1 proteins in the same cell types led us to believe that there might be a relationship between GR and GLUT 1 expressions at the cellular level. GLUT 1 does not play a pivotal role in diabetic pregnancies. However, placental growth abnormalities during diabetic pregnancy may be related to the amount of GR.