Role of Placental Glucose Transporters in Determining Fetal Growth.

Maternal nutrient availability and its transport through the placenta are crucial for fetal development. Nutrients are transported to the fetus via specific transporters present on the microvillous (MVM) and basal membrane (BM) of the placenta. Glucose is the most abundant nutrient transferred to the fetus and plays a key role in the fetal growth and development. The transfer of glucose across the human placenta is directly proportional to maternal glucose concentrations, and is mediated by glucose transporter family proteins (GLUTs). Maternal glucose concentration influences expression and activity of GLUTs in the MVM (glucose uptake) and BM (glucose delivery). Alteration in the number and function of these transporters may affect the growth and body composition of the fetus. The thin-fat phenotype of the Indian baby (low ponderal index, high adiposity) is proposed as a harbinger of future metabolic risk. We propose that placental function mediated through nutrient transporters contributes to the phenotype of the baby, specifically that glucose transporters will influence neonatal fat. This review discusses the role of various glucose transporters in the placenta in determining fetal growth and body composition, in light of the above hypothesis.

Unravelling the potential of angiogenic factors for the early prediction of preeclampsia.

Preeclampsia is a multisystem, multiorgan hypertensive disorder of pregnancy responsible for maternal and perinatal morbidity and mortality in low- and middle-income countries. The classic diagnostic features hold less specificity for preeclampsia and its associated adverse outcomes, suggesting a need for specific and reliable biomarkers for the early prediction of preeclampsia. The imbalance of pro- and antiangiogenic circulatory factors contributes to the pathophysiology of preeclampsia. Several studies have examined the profile of angiogenic factors in preeclampsia to search for a biomarker that will improve the diagnostic ability of preeclampsia and associated adverse outcomes. This may help in more efficient patient management and the reduction of associated health care costs. This article reviews the findings from previous studies published to date on angiogenic factors and suggests a need to apply a multivariable model from the beginning of pregnancy and continuing throughout gestation for the early and specific prediction of preeclampsia.

Differential Expression of Nerve Growth Factor (NGF) and Brain Derived Neurotrophic Factor (BDNF) in Different Regions of Normal and Preeclampsia Placentae.

Background: Our recent study indicates differential protein levels of neurotrophins and angiogenic factors in various regions of the normotensive and preeclampsia (PE) placenta. These changes may be in a response to differential mRNA expression of neurotrophins.Methods: This study examines the mRNA levels of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) in different regions of the placenta in normotensive control (NC) women and women with PE. Thirty NC women and forty one women with PE (18 delivered at term [T-PE] and 23 delivered preterm [PT-PE]) were included in the study. Placental samples were taken from four regions: central basal (CM), central chorionic (CF), peripheral basal (PM), and peripheral chorionic (PF). The mRNA levels of neurotrophins were measured by quantitative real-time PCR.Results: The BDNF mRNA levels were higher in peripheral fetal region as compared to peripheral basal region in NC (p < 0.05) group, PE group (p < 0.05) and term PE group (p < 0.01). The BDNF mRNA levels were lower in the central basal region of preterm PE group (p < 0.05) as compared to the NC group.Conclusion: The present study indicates that NGF and BDNF are expressed differentially across various regions of the placenta. This has implications for selection of the sampling site in the placenta while carrying out placental studies.

Matrix metalloproteinases-2 (MMP-2) and matrix metalloproteinases -9 (MMP-9) are differentially expressed in different regions of normal and preeclampsia placentae.

Matrix metalloproteinases (MMPs) are involved in the extracellular matrix (ECM) remodeling during human placentation and parturition and have been shown to be associated with oxidative stress. Placental regional changes in oxygen availability and oxidative stress indices may influence regional differences in expression of MMPs. This study examines the protein and mRNA levels of MMP-2 and MMP-9 in different regions of the placenta in normotensive control (NC) women and women with preeclampsia (PE). Fifty-two NC women and 43 women with PE (18 delivered at term [T-PE] and 25 delivered preterm [PT-PE]) were recruited. Placental samples were taken from four regions: central basal (CM), central chorionic (CF), peripheral basal (PM), and peripheral chorionic (PF). MMP protein and mRNA levels were measured by ELISA and quantitative real time PCR, respectively. MMP-2 protein levels were higher in all the placental regions (P < 0.05) from PT-PE group as compared to the respective regions from the NC and T-PE groups. MMP-9 mRNA levels were higher in CM region as compared to CF and PM regions (P < 0.05) in the NC group and compared to CF and PF regions (P < 0.05) in the T-PE group. The MMP-9 mRNA levels were lower in the CF region in the PT-PE and T-PE groups (P < 0.05) as compared to the NC group. Elevated levels of MMP-2 protein levels were observed in all regions of PT-PE placenta possibly influencing the degradation of placental ECM. Lower mRNA expression of MMP-9 both in PT-PE and T-PE may contribute to a disturbed placental vascularization.

VEGF and VEGFR1 levels in different regions of the normal and preeclampsia placentae.

Altered placental angiogenesis is implicated in the pathophysiology of preeclampsia. We have earlier reported placental regional differences in oxidative stress markers and neurotrophins. Oxidative stress and neurotrophins are reported to regulate angiogenesis. This study aims to examine protein and mRNA levels of vascular endothelial growth factor (VEGF) and VEGF receptor 1 (VEGFR1) in four regions [central maternal (CM), central fetal (CF), peripheral maternal (PM), and peripheral fetal (PF)] of the placenta in normotensive control (NC) women (n = 51) and women with preeclampsia (PE) (n = 43) [18 delivered at term (T-PE) and 25 delivered preterm (PT-PE)]. In all groups, CF region reported highest VEGF protein levels compared to all other regions. VEGF mRNA level was higher in CF region as compared to CM region in PE group (p < 0.05). VEGF levels were lower in all regions of PE, T-PE, and PT-PE groups (p < 0.05) as compared to their respective regions in NC group. VEGFR1 levels were lower in CF (p < 0.05) and PF (p < 0.01) regions as compared to CM region only in control. However, VEGFR1 levels were higher in CF (p < 0.05) and PF (p < 0.01) regions of PT-PE group as compared to control. VEGFR1 mRNA level was higher in PM region of PE group and T-PE group (p < 0.05 for both) as compared to control. VEGF levels in the PF region were positively associated with birth weight and placental weight. This study describes placental regional changes in angiogenic factors particularly highlighting increased VEGF in CF region possibly in response to hypoxic conditions prevailing in placenta.

Regional changes of placental vascularization in preeclampsia: a review.

Preeclampsia is characterized by vascular dysfunction and results in maternal and fetal morbidity and mortality. The placenta plays a critical role in the growth and development of the fetus, and recent studies indicate that placental architecture, oxygen availability, and oxidative stress indices vary across different regions of the placenta. Our earlier studies have reported altered maternal angiogenesis and differential placental gene expression and methylation patterns of angiogenic factors in women with preeclampsia when compared with normotensive women. We have also demonstrated lower maternal and placental neurotrophin (NT) levels in women with preeclampsia. Studies suggest that oxidative stress is associated with proteases like matrix metalloproteinases (MMPs) and growth factors like NTs and angiogenic factors known to be involved in the process of angiogenesis. Recently, we have reported regionwise differential oxidative stress, antioxidant enzyme activity, and NT levels in placenta from normotensive control women and women with preeclampsia. The current review describes the regional changes in the placenta and highlights the role of placental oxidative stress in influencing regional differences in the expression of angiogenic factors, MMPs, and NTs. This review discusses the need for further research on various growth factors and proteins involved in the process of placental development across different regions of the placenta. This would help to understand whether regional differences in these factors affect the growth and development of the fetus.

Regional differences in the placental levels of oxidative stress markers in pre-eclampsia.

OBJECTIVE: To examine placental malondialdehyde (MDA), catalase, and glutathione peroxidase (GPx) levels in four placental regions among women with and without pre-eclampsia. METHODS: A cross-sectional study was conducted among women aged 18-35 years with a singleton pregnancy in Pune, India, between May 3, 2013, and June 16, 2014. Three groups were enrolled: normotensive; pre-eclampsia, delivered at term; and pre-eclampsia, delivered preterm. Samples were collected from the central and peripheral placental regions (maternal and fetal sides) immediately after delivery. RESULTS: A total of 60 women were enrolled (35 normotensive; 11 with pre-eclampsia delivered at term; 14 with pre-eclampsia, delivered preterm). MDA levels were higher in all regions of the placenta among the pre-eclampsia versus normotensive groups (P<0.01). MDA levels were higher in the central maternal region than in the central fetal region in the preterm pre-eclampsia group (P=0.023). The MDA levels in the central maternal region were also higher in the preterm than in the term pre-eclampsia group (P=0.014). Catalase activity was lower in the peripheral maternal (P=0.036) and fetal (P=0.050) regions in the preterm pre-eclampsia group versus the normotensive group. The activity of GPx was higher in the peripheral maternal region than in the central fetal region in the normotensive group (P=0.033). CONCLUSION: Pre-eclampsia might be characterized by differential placental oxidative stress and antioxidant enzyme activity.

A longitudinal study of circulating angiogenic and antiangiogenic factors and AT1-AA levels in preeclampsia.

Our earlier studies of preeclampsia (PE) at delivery have demonstrated the alteration of one carbon cycle, reduced placental omega 3 fatty acids, altered circulating levels of angiogenic factors and differential placental gene-specific methylation patterns of angiogenic factors. This study was undertaken to examine changes in the levels of angiogenic factors and angiotensin II type 1 receptor autoantibodies (AT1-AAs) throughout gestation, from early pregnancy until delivery, in women with PE and to examine their association with cord angiogenic factors, blood pressure and infant weight. A total of 81 pregnant women (46 normotensive and 35 with PE) were followed at three different time points during pregnancy: 16-20 weeks (T1), 26-30 weeks (T2) and at the time of delivery (T3). The plasma levels of angiogenic factors and AT1-AAs were determined in the maternal and cord plasma by commercial enzyme-linked immunosorbent assay kits. Maternal plasma levels of vascular endothelial growth factor (VEGF) and placental growth factor (PlGF) were lower (P<0.05 for both), whereas soluble fms-like tyrosine kinase-1 (sFlt-1; P<0.05) and the sFlt-1/PlGF ratio (P<0.01) were higher in early pregnancy in the PE group. Maternal plasma AT1-AA levels were higher (P<0.05) at T2 in women with PE. Cord plasma VEGF and soluble kinase insert domain receptor (sKDR) levels were lower (P<0.01 and P<0.05, respectively), whereas AT1-AA levels were higher (P<0.05) in the PE group. Maternal plasma VEGF levels in early pregnancy were positively associated with systolic blood pressure, whereas the sFlt-1/PlGF ratio at T2 was negatively associated with infant weight in the PE group. Low levels of proangiogenic factors (VEGF and PlGF) and high levels of AT1-AAs and antiangiogenic factors (sFlt-1 and sFlt-1/PlGF ratio) are present in the maternal circulation during early gestation in women with PE.