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Kumar S, Song R, Mishra JS. Elevated gestational testosterone impacts vascular and uteroplacental function. Placenta 2023:S0143-4004(23)00598-2. [PMID: 37977936 PMCID: PMC11087376 DOI: 10.1016/j.placenta.2023.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 11/04/2023] [Accepted: 11/07/2023] [Indexed: 11/19/2023]
Abstract
Maternal vascular adaptations to establish an adequate blood supply to the uterus and placenta are essential for optimal nutrient and oxygen delivery to the developing fetus in eutherian mammals, including humans. Numerous factors contribute to maintaining appropriate hemodynamics and placental vascular development throughout pregnancy. Failure to achieve or sustain these pregnancy-associated changes in women is strongly associated with an increased risk of antenatal complications, such as preeclampsia, a hypertensive disorder of pregnancy. The precise etiology of preeclampsia is unknown, but emerging evidence points to a potential role for androgens. The association between androgens and maternal cardiovascular and placental function merits particular attention due to the notable 2- to 3-fold elevated plasma testosterone (T) levels observed in preeclampsia. T levels in preeclamptic women positively correlate with vascular dysfunction, and preeclampsia is associated with increased androgen receptor (AR) levels in placental tissues. Moreover, animal studies replicating the pattern and magnitude of T increase observed in preeclamptic pregnancies have reproduced key features of preeclampsia, including gestational hypertension, endothelial dysfunction, heightened vasoconstriction to angiotensin II, impaired spiral artery remodeling, placental hypoxia, reduced nutrient transport, and fetal growth restriction. Collectively, these findings suggest that AR-mediated activity plays a significant role in the clinical presentation of preeclampsia. This review critically evaluates this hypothesis, considering both clinical and preclinical evidence.
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Affiliation(s)
- Sathish Kumar
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, 53706, USA; Department of Obstetrics and Gynecology, School of Medicine and Public Health, University of Wisconsin, Madison, WI, 53792, USA.
| | - Ruolin Song
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, 53706, USA
| | - Jay S Mishra
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, 53706, USA
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2
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Mangwiro YTM, Cuffe JSM, Mahizir D, Anevska K, Gravina S, Romano T, Moritz KM, Briffa JF, Wlodek ME. Exercise initiated during pregnancy in rats born growth restricted alters placental mTOR and nutrient transporter expression. J Physiol 2019; 597:1905-1918. [PMID: 30734290 DOI: 10.1113/jp277227] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 01/24/2019] [Indexed: 02/06/2023] Open
Abstract
KEY POINTS Fetal growth is dependent on effective placental nutrient transportation, which is regulated by mammalian target of rapamycin (mTOR) complex 1 modulation of nutrient transporter expression. These transporters are dysregulated in pregnancies affected by uteroplacental insufficiency and maternal obesity. Nutrient transporters and mTOR were altered in placentae of mothers born growth restricted compared to normal birth weight dams, with maternal diet- and fetal sex-specific responses. Exercise initiated during pregnancy downregulated mTOR protein expression, despite an increase in mTOR activation in male associated placentae, and reduced nutrient transporter gene abundance, which was also dependent on maternal diet and fetal sex. Limited changes were characterized with exercise initiated before and continued throughout pregnancy in nutrient transporter and mTOR expression. Maternal exercise during pregnancy differentially regulated mTOR and nutrient transporters in a diet- and sex-specific manner, which likely aimed to improve late gestational placental growth and neonatal survival. ABSTRACT Adequate transplacental nutrient delivery is essential for fetoplacental development. Intrauterine growth restriction and maternal obesity independently alter placental nutrient transporter expression. Although exercise is beneficial for maternal health, limited studies have characterized how the timing of exercise initiation influences placental nutrient transport. Therefore, this study investigated the impact of maternal exercise on placental mechanistic target of rapamycin (mTOR) and nutrient transporter expression in growth restricted mothers and whether these outcomes were dependent on maternal diet or fetal sex. Uteroplacental insufficiency or sham surgery was induced on embryonic day (E) 18 in Wistar-Kyoto rats. F1 offspring were fed a chow or high-fat diet from weaning and at 16 weeks were randomly allocated to an exercise protocol: sedentary, exercised prior to and during pregnancy, or exercised during pregnancy only. Females were mated with normal males (20 weeks) and F2 placentae collected at E20. Exercise during pregnancy only, reduced mTOR protein expression in all groups and increased mTOR activation in male associated placentae. Exercise during pregnancy only, decreased the expression of amino acid transporters in a diet- and sex-specific manner. Maternal growth restriction altered mTOR and system A amino acid transporter expression in a sex- and diet-specific manner. These data highlight that maternal exercise initiated during pregnancy alters placental mTOR expression, which may directly regulate amino acid transporter expression, to a greater extent than exercise initiated prior to and continued during pregnancy, in a diet- and fetal sex-dependent manner. These findings highlight that the timing of exercise initiation is important for optimal placental function.
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Affiliation(s)
- Yeukai T M Mangwiro
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Bundoora, Victoria, 3083, Australia.,Department of Physiology, University of Melbourne, Parkville, Victoria, 3010, Australia
| | - James S M Cuffe
- School of Biomedical Sciences, University of Queensland, St Lucia, Queensland, 4072, Australia
| | - Dayana Mahizir
- Department of Physiology, University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Kristina Anevska
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Bundoora, Victoria, 3083, Australia.,Department of Physiology, University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Sogand Gravina
- Department of Physiology, University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Tania Romano
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Bundoora, Victoria, 3083, Australia
| | - Karen M Moritz
- School of Biomedical Sciences, University of Queensland, St Lucia, Queensland, 4072, Australia.,Child Health Research Centre, University of Queensland, South Brisbane, Queensland, 4101, Australia
| | - Jessica F Briffa
- Department of Physiology, University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Mary E Wlodek
- Department of Physiology, University of Melbourne, Parkville, Victoria, 3010, Australia
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3
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Dubé C, Aguer C, Adamo K, Bainbridge S. A role for maternally derived myokines to optimize placental function and fetal growth across gestation. Appl Physiol Nutr Metab 2017; 42:459-469. [DOI: 10.1139/apnm-2016-0446] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Exercise during pregnancy is associated with improved health outcomes for both mother and baby, including a reduced risk of future obesity and susceptibility to chronic diseases. Overwhelming evidence demonstrates a protective effect of maternal exercise against fetal birth weight extremes, reducing the rates of both large- and small-for-gestational-age infants. It is speculated that this protective effect is mediated in part through exercise-induced regulation of maternal physiology and placental development and function. However, the specific mechanisms through which maternal exercise regulates these changes remain to be discovered. We hypothesize that myokines, a collection of peptides and cytokines secreted from contracting skeletal muscles during exercise, may be an important missing link in the story. Myokines are known to reduce inflammation, improve metabolism and enhance macronutrient transporter expression and activity in various tissues of nonpregnant individuals. Little research to date has focused on the specific roles of the myokine secretome in the context of pregnancy; however, it is likely that myokines secreted from exercising skeletal muscles may modulate the maternal milieu and directly impact the vital organ of pregnancy—the placenta. In the current review, data in strong support of this potential role of myokines will be presented, suggesting myokine secretion as a key mechanism through which maternal exercise optimizes fetal growth trajectories. It is clear that further research is warranted in this area, as knowledge of the biological roles of myokines in the context of pregnancy would better inform clinical recommendations for exercise during pregnancy and contribute to the development of important therapeutic interventions.
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Affiliation(s)
- Chantal Dubé
- Interdisciplinary School of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Céline Aguer
- Institut de recherche de l’Hôpital Montfort, Ottawa, ON K1K 0T1, Canada
- Biochemistry, Microbiology and Immunology department, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Kristi Adamo
- School of Human Kinetics, University of Ottawa, Ottawa, ON K1N 1A2, Canada
- Healthy Active Living and Obesity Research Group, Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON K1H 8L1, Canada
| | - Shannon Bainbridge
- Interdisciplinary School of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
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Fried RL, Mayol NL, McDade TW, Kuzawa CW. Maternal metabolic adaptations to pregnancy among young women in Cebu, Philippines. Am J Hum Biol 2017; 29. [PMID: 28429514 DOI: 10.1002/ajhb.23011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 01/27/2017] [Accepted: 04/01/2017] [Indexed: 12/22/2022] Open
Abstract
OBJECTIVES Evidence that fetal development has long-term impacts on health has increased interest in maternal-fetal nutrient exchange. Although maternal metabolism is known to change during gestation to accommodate fetal nutrient demands, little is known about these modifications outside of a Western, clinical context. This study characterizes maternal metabolic adaptations to pregnancy, and their associations with offspring birth weight (BW), among women living in the Philippines. METHODS Fasting glucose, triglycerides, insulin, leptin, and adiponectin were assessed in 808 participants in the Cebu Longitudinal Health and Nutrition Survey (Metropolitan Cebu, Philippines). Cross-sectional relationships between metabolites and hormones and gestational and lactational status were evaluated. Among the subset of currently pregnant women, associations between maternal glucose and triglycerides and offspring BW were also examined. RESULTS Women in their second and third trimesters had significantly lower fasting glucose and adiponectin compared to nulliparous women, and leptin levels and triglyceride levels were notably higher late in pregnancy (all P < .05). Among pregnant women, fasting glucose was a positive predictor of offspring BW, but only in males (P = .012, R2 = .28). Hormones and metabolites in post-partum women trend back toward levels found in nulliparous women, with some differences by breastfeeding status. CONCLUSIONS We find evidence for marked changes in maternal lipid and carbohydrate metabolism during pregnancy, consistent with known adaptations to support fetal growth. The finding of sex-specific relationships between maternal glucose and offspring BW adds to evidence for greater impacts of the maternal-gestational environment on biology and health in male offspring.
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Affiliation(s)
- Ruby L Fried
- Department of Anthropology, Northwestern University, Evanston, Illinois, 60208
| | - Nanette L Mayol
- USC - Office of Population Studies Foundation, University of San Carlos, Talamban, Cebu City, 6000, Philippines
| | - Thom W McDade
- Department of Anthropology, Northwestern University, Evanston, Illinois, 60208.,Cells 2 Society, The Center for Social Disparities and Health at the Institute for Policy Research, Northwestern University, Evanston, Illinois, 60208
| | - Christopher W Kuzawa
- Department of Anthropology, Northwestern University, Evanston, Illinois, 60208.,Cells 2 Society, The Center for Social Disparities and Health at the Institute for Policy Research, Northwestern University, Evanston, Illinois, 60208
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Fontana R, Della Torre S. The Deep Correlation between Energy Metabolism and Reproduction: A View on the Effects of Nutrition for Women Fertility. Nutrients 2016; 8:87. [PMID: 26875986 PMCID: PMC4772050 DOI: 10.3390/nu8020087] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 01/21/2016] [Accepted: 02/02/2016] [Indexed: 01/01/2023] Open
Abstract
In female mammals, mechanisms have been developed, throughout evolution, to integrate environmental, nutritional and hormonal cues in order to guarantee reproduction in favorable energetic conditions and to inhibit it in case of food scarcity. This metabolic strategy could be an advantage in nutritionally poor environments, but nowadays is affecting women's health. The unlimited availability of nutrients, in association with reduced energy expenditure, leads to alterations in many metabolic pathways and to impairments in the finely tuned inter-relation between energy metabolism and reproduction, thereby affecting female fertility. Many energetic states could influence female reproductive health being under- and over-weight, obesity and strenuous physical activity are all conditions that alter the profiles of specific hormones, such as insulin and adipokines, thus impairing women fertility. Furthermore, specific classes of nutrients might affect female fertility by acting on particular signaling pathways. Dietary fatty acids, carbohydrates, proteins and food-associated components (such as endocrine disruptors) have per se physiological activities and their unbalanced intake, both in quantitative and qualitative terms, might impair metabolic homeostasis and fertility in premenopausal women. Even though we are far from identifying a "fertility diet", lifestyle and dietary interventions might represent a promising and invaluable strategy to manage infertility in premenopausal women.
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Affiliation(s)
- Roberta Fontana
- Department of Pharmacological and Biomolecular Sciences, University of Milan, via Balzaretti 9, Milan 20133, Italy.
- Department of Drug Discovery and Development, Italian Institute of Technology, via Morego 30, Genova 16163, Italy.
| | - Sara Della Torre
- Department of Pharmacological and Biomolecular Sciences, University of Milan, via Balzaretti 9, Milan 20133, Italy.
- Center of Excellence of Neurodegenerative Diseases, University of Milan, via Balzaretti 9, Milan 20133, Italy.
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Dunlap KA, Brown JD, Keith AB, Satterfield MC. Factors controlling nutrient availability to the developing fetus in ruminants. J Anim Sci Biotechnol 2015; 6:16. [PMID: 25908972 PMCID: PMC4407308 DOI: 10.1186/s40104-015-0012-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 03/23/2015] [Indexed: 01/20/2023] Open
Abstract
Inadequate delivery of nutrients results in intrauterine growth restriction (IUGR), which is a leading cause of neonatal morbidity and mortality in livestock. In ruminants, inadequate nutrition during pregnancy is often prevalent due to frequent utilization of exensive forage based grazing systems, making them highly susceptible to changes in nutrient quality and availability. Delivery of nutrients to the fetus is dependent on a number of critical factors including placental growth and development, utero-placental blood flow, nutrient availability, and placental metabolism and transport capacity. Previous findings from our laboratory and others, highlight essential roles for amino acids and their metabolites in supporting normal fetal growth and development, as well as the critical role for amino acid transporters in nutrient delivery to the fetus. The focus of this review will be on the role of maternal nutrition on placental form and function as a regulator of fetal development in ruminants.
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Affiliation(s)
- Kathrin A Dunlap
- Department of Animal Science, Texas A&M University, 2471 TAMU, College Station, Texas 77843 USA
| | - Jacob D Brown
- Department of Animal Science, Texas A&M University, 2471 TAMU, College Station, Texas 77843 USA
| | - Ashley B Keith
- Department of Animal Science, Texas A&M University, 2471 TAMU, College Station, Texas 77843 USA
| | - M Carey Satterfield
- Department of Animal Science, Texas A&M University, 2471 TAMU, College Station, Texas 77843 USA
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7
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Sánchez-Pintos P, Pérez-Muñuzuri A, Cocho JÁ, Fernández-Lorenzo JR, Fraga JM, Couce ML. Evaluation of carnitine deficit in very low birth weight preterm newborns small for their gestational age. J Matern Fetal Neonatal Med 2015; 29:933-7. [PMID: 25777790 DOI: 10.3109/14767058.2015.1024647] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE To verify whether small-for-gestational-age (SGA) preterm newborns represent a special risk group for carnitine deficiency. Secondary outcome includes assessment of longitudinal differences of total carnitine (TC), free carnitine (FC) and acylcarnitines between SGA and appropriate-for-gestational-age (AGA). METHODS A retrospective study to evaluate carnitine and acylcarnitines profile on 144 very-low-birth weight newborns (VLBW), classified as AGA (n = 73) and SGA (n = 71), was performed by tandem mass spectrometry, during their first 5 weeks of life. Carnitine deficiency was defined as FC <40 µmol/L and FC/TC <0.7. RESULTS Carnitine deficiency was observed in the two study groups throughout the monitoring period (maximum FC: 36.05 µmol/L in AGA and 32.24 µmol/L in SGA). FC/TC remains under 0.7 in both with progressive improvement. Unlike expected, a comparatively higher value of TC, FC and total acylcarnitines (tAC) was found in SGA during the first 2 weeks, with significant relevance on day 3-5, especially for tAC (p < 0.001). The only acylcarnitine with persistently lower value in SGA is C5 (p < 0.05 in first 2 weeks). CONCLUSIONS A carnitine deficiency was demonstrated in all VLBW. Although birth weight restriction has been suggested as a risk factor for impaired carnitine status, in our study, SGA was not related with higher carnitine deficiency.
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Affiliation(s)
| | - Alejandro Pérez-Muñuzuri
- b Neonatal Unit, Department of Pediatrics , Complexo Hospitalario Universitario de Santiago de Compostela , Santiago de Compostela , Spain
| | - Jose Ángel Cocho
- c Diagnosis and Treatment Unit of Metabolic Diseases , Complexo Hospitalario Universitario de Santiago de Compostela , Santiago de Compostela , Spain , and
| | | | - Jose María Fraga
- b Neonatal Unit, Department of Pediatrics , Complexo Hospitalario Universitario de Santiago de Compostela , Santiago de Compostela , Spain .,c Diagnosis and Treatment Unit of Metabolic Diseases , Complexo Hospitalario Universitario de Santiago de Compostela , Santiago de Compostela , Spain , and
| | - Maria L Couce
- b Neonatal Unit, Department of Pediatrics , Complexo Hospitalario Universitario de Santiago de Compostela , Santiago de Compostela , Spain .,c Diagnosis and Treatment Unit of Metabolic Diseases , Complexo Hospitalario Universitario de Santiago de Compostela , Santiago de Compostela , Spain , and
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8
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Aiko Y, Askew DJ, Aramaki S, Myoga M, Tomonaga C, Hachisuga T, Suga R, Kawamoto T, Tsuji M, Shibata E. Differential levels of amino acid transporters System L and ASCT2, and the mTOR protein in placenta of preeclampsia and IUGR. BMC Pregnancy Childbirth 2014; 14:181. [PMID: 24886642 PMCID: PMC4060848 DOI: 10.1186/1471-2393-14-181] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 05/22/2014] [Indexed: 12/14/2022] Open
Abstract
Background Sufficient amino acid transport activity (AAT) is indispensable for appropriate fetal growth. Studies suggest that placental nutrient uptake activity is responsive to both maternal and fetal nutrient demands. We hypothesize that under conditions of limited nutrient availability to the fetus, as often present in preeclampsia, intrauterine growth restriction (IUGR), and insufficient weight-gain during pregnancy, a general adaptive response aimed to increase amino acid transport activity may be observed in the placenta. Method A total of 40 placentas from full-term (n = 10) and pre-term (average gestational period = 34.8 weeks, n = 10) normal pregnancies, IUGR (n = 10), and preeclampsia (n = 10) associated pregnancies were looked at by immunohistochemistry followed by relative qualitative scoring to compare expression levels and localization of System L, ASCT2, and mTOR proteins. Result Microvillous syncytiotrophoblast (ST) in placenta of pregnancies complicated by IUGR or preeclampsia (PE) showed significant increases in the levels of System L amino acid transport proteins 4F2hc and LAT1 compared to both full-term control and pre-term (early gestation control) pregnancies seperately (p < 0.05). Elevated mTOR protein was uniquely higher in IUGR placentas compared to full-term controls (P = 0.0026). Total cellular ASCT2 transporter protein levels were similar in all groups, however, levels of ASCT2 protein localized to the ST microvillous membrane (MVM) were significantly lower in IUGR compared to both full-term and pre-term pregnancies (P = 0.0006, 0.03, respectively). Additionally, ASCT2 and mTOR protein levels were positively associated with maternal pre-pregnancy BMI (P = 0.046, 0.048, respectively). Conclusion There are three important findings based upon the present study. First, in conditions of limited nutrient availability, such as PE or IUGR, there is an overall increase in the level of System L and mTOR protein expression in the ST, suggestive of an adaptive response. Second, a decrease in ASCT2 protein at the ST MVM suggests a post-translational event that may decrease AAT activity in IUGR placentas. Third, a physiological link between transporter expression and pre-pregnancy BMI is suggested based upon a positive association observed with ASCT2 and mTOR expression values.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Eiji Shibata
- Department of Obstetrics and Gynecology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Fukuoka, Japan.
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Braun T, Challis JR, Newnham JP, Sloboda DM. Early-life glucocorticoid exposure: the hypothalamic-pituitary-adrenal axis, placental function, and long-term disease risk. Endocr Rev 2013; 34:885-916. [PMID: 23970762 DOI: 10.1210/er.2013-1012] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
An adverse early-life environment is associated with long-term disease consequences. Adversity early in life is hypothesized to elicit developmental adaptations that serve to improve fetal and postnatal survival and prepare the organism for a particular range of postnatal environments. These processes, although adaptive in their nature, may later prove to be maladaptive or disadvantageous if the prenatal and postnatal environments are widely discrepant. The exposure of the fetus to elevated levels of either endogenous or synthetic glucocorticoids is one model of early-life adversity that contributes substantially to the propensity of developing disease. Moreover, early-life glucocorticoid exposure has direct clinical relevance because synthetic glucocorticoids are routinely used in the management of women at risk of early preterm birth. In this regard, reports of adverse events in human newborns have raised concerns about the safety of glucocorticoid treatment; synthetic glucocorticoids have detrimental effects on fetal growth and development, childhood cognition, and long-term behavioral outcomes. Experimental evidence supports a link between prenatal exposure to synthetic glucocorticoids and alterations in fetal development and changes in placental function, and many of these alterations appear to be permanent. Because the placenta is the conduit between the maternal and fetal environments, it is likely that placental function plays a key role in mediating effects of fetal glucocorticoid exposure on hypothalamic-pituitary-adrenal axis development and long-term disease risk. Here we review recent insights into how the placenta responds to changes in the intrauterine glucocorticoid environment and discuss possible mechanisms by which the placenta mediates fetal hypothalamic-pituitary-adrenal development, metabolism, cardiovascular function, and reproduction.
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Affiliation(s)
- Thorsten Braun
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, 1280 Main Street West, HSC 4H30A, Hamilton, Ontario, Canada L8S 4K1.
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10
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Deloison B, Millischer AE, Salomon LJ. IRM placentaire : physiologie et pathologie. ACTA ACUST UNITED AC 2013; 41:394-403. [DOI: 10.1016/j.gyobfe.2013.04.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 04/09/2013] [Indexed: 10/26/2022]
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Boeuf P, Aitken EH, Chandrasiri U, Chua CLL, McInerney B, McQuade L, Duffy M, Molyneux M, Brown G, Glazier J, Rogerson SJ. Plasmodium falciparum malaria elicits inflammatory responses that dysregulate placental amino acid transport. PLoS Pathog 2013; 9:e1003153. [PMID: 23408887 PMCID: PMC3567154 DOI: 10.1371/journal.ppat.1003153] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 11/21/2012] [Indexed: 01/09/2023] Open
Abstract
Placental malaria (PM) can lead to poor neonatal outcomes, including low birthweight due to fetal growth restriction (FGR), especially when associated with local inflammation (intervillositis or IV). The pathogenesis of PM-associated FGR is largely unknown, but in idiopathic FGR, impaired transplacental amino acid transport, especially through the system A group of amino acid transporters, has been implicated. We hypothesized that PM-associated FGR could result from impairment of transplacental amino acid transport triggered by IV. In a cohort of Malawian women and their infants, the expression and activity of system A (measured by Na+-dependent 14C-MeAIB uptake) were reduced in PM, especially when associated with IV, compared to uninfected placentas. In an in vitro model of PM with IV, placental cells exposed to monocyte/infected erythrocytes conditioned medium showed decreased system A activity. Amino acid concentrations analyzed by reversed phase ultra performance liquid chromatography in paired maternal and cord plasmas revealed specific alterations of amino acid transport by PM, especially with IV. Overall, our data suggest that the fetoplacental unit responds to PM by altering its placental amino acid transport to maintain adequate fetal growth. However, IV more profoundly compromises placental amino acid transport function, leading to FGR. Our study offers the first pathogenetic explanation for FGR in PM. Malaria infection during pregnancy can cause fetal growth restriction and low birthweight associated with high infant mortality and morbidity rates. The pathogenesis of fetal growth restriction in placental malaria is largely unknown, but in other pathological pregnancies, impaired transplacental amino acid transport has been implicated. In a cohort of Malawian women and their infants, we found that placental malaria, especially when associated with local inflammation, was associated with decreased expression and activity of an important group of amino acid placental transporters. Using an in vitro model of placental malaria with local inflammation, we discovered that maternal monocyte products could impair the activity of amino acid transporters on placental cells. Amino acid concentrations in paired maternal and cord plasmas revealed specific alterations of amino acid transport by placental malaria, especially with local inflammation. Overall, our data suggest that, more than malaria infection per se, the local inflammation it triggers compromises placental amino acid transport function, leading to fetal growth restriction. Greater understanding of the mechanisms involved, combined with interventions to improve fetal growth in malaria, are important priorities in areas of the world where the co-existence of malaria and maternal malnutrition threatens the health and lives of millions of young babies.
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Affiliation(s)
- Philippe Boeuf
- The University of Melbourne, Department of Medicine-RMH, Parkville, Victoria, Australia.
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Plaks V, Sapoznik S, Berkovitz E, Haffner-Krausz R, Dekel N, Harmelin A, Neeman M. Functional phenotyping of the maternal albumin turnover in the mouse placenta by dynamic contrast-enhanced MRI. Mol Imaging Biol 2011; 13:481-492. [PMID: 20686857 PMCID: PMC3087877 DOI: 10.1007/s11307-010-0390-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Purpose The purpose of this study was to develop a tool for functional phenotyping of the maternal circulation in the mouse placenta. Procedures In utero macromolecular dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) was performed on embryonic day 10.5 (E10.5), E13.5, and E18.5. Fluorescence analysis was also used for validation of the results. Results The initial rate of contrast enhancement revealed an increased maternal blood volume fraction as the pregnancy progressed. Serial imaging of E10.5 and E13.5 placentas revealed a loss of contrast enhancement due to phagocytic uptake. A key application of macromolecular DCE-MRI would be to follow mouse pregnancies during fetal and placental manipulation including embryo transfer, tetraploid complementation, and fetal resorptions. We were able to resolve strain differences in ICR outbred mice carrying both ICR and C57Bl/6J embryos and to differentiate in utero resorptions from functional placentas. Conclusions Our results highlight the importance of the functional in utero analysis of placental vascularization in physiological phenotyping of transgenic mice and suggest MRI, particularly macromolecular DCE-MRI, as a non-invasive tool for the analysis of the placenta.
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Affiliation(s)
- Vicki Plaks
- Biological Regulation, The Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Stav Sapoznik
- Biological Regulation, The Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Elina Berkovitz
- Veterinary Resources, The Weizmann Institute of Science, Rehovot, 76100, Israel
| | | | - Nava Dekel
- Biological Regulation, The Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Alon Harmelin
- Veterinary Resources, The Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Michal Neeman
- Biological Regulation, The Weizmann Institute of Science, Rehovot, 76100, Israel.
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Sathishkumar K, Elkins R, Chinnathambi V, Gao H, Hankins GDV, Yallampalli C. Prenatal testosterone-induced fetal growth restriction is associated with down-regulation of rat placental amino acid transport. Reprod Biol Endocrinol 2011; 9:110. [PMID: 21812961 PMCID: PMC3162507 DOI: 10.1186/1477-7827-9-110] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Accepted: 08/03/2011] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Exposure of pregnant mothers to elevated concentrations of circulating testosterone levels is associated with fetal growth restriction and delivery of small-for-gestational-age babies. We examined whether maternal testosterone crosses the placenta to directly suppress fetal growth or if it modifies placental function to reduce the capacity for transport of nutrients to the fetus. METHODS Pregnant rats were exposed to testosterone propionate (TP; 0.5 mg/kg) by daily subcutaneous injection from gestational days (GD) 15-19. Maternal and fetal testosterone levels, placental nutrient transport activity and expression of transporters and birth weight of pups and their anogenital distances were determined. RESULTS This dose of TP doubled maternal testosterone levels but had no effect on fetal testosterone levels. Maternal daily weight gain was significantly lower only on GD 19 in TP treated dams compared to controls. Placental weight and birth weight of pups were significantly reduced, but the anogenital distance of pups were unaffected by TP treatment. Maternal plasma amino acids concentrations were altered following testosterone exposure, with decreases in glutamine, glycine, tyrosine, serine, proline, and hydroxyproline and increases in asparagine, isoleucine, leucine, lysine, histidine and arginine. In the TP dams, placental system A amino acid transport activity was significantly reduced while placental glucose transport capacity was unaffected. Decreased expression of mRNA and protein levels of slc38a2/Snat2, an amino acid transporter, suggests that reduced transporter proteins may be responsible for the decrease in amino acid transport activity. CONCLUSIONS Taken together, these data suggest that increased maternal testosterone concentrations do not cross the placenta to directly suppress fetal growth but affects amino acid nutrient delivery to the fetus by downregulating specific amino acid transporter activity.
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Affiliation(s)
- Kunju Sathishkumar
- Department of Obstetrics and Gynecology, The University of Texas Medical Branch Galveston, Texas, USA
| | - Rebekah Elkins
- Department of Obstetrics and Gynecology, The University of Texas Medical Branch Galveston, Texas, USA
| | - Vijayakumar Chinnathambi
- Department of Obstetrics and Gynecology, The University of Texas Medical Branch Galveston, Texas, USA
| | - Haijun Gao
- Department of Obstetrics and Gynecology, The University of Texas Medical Branch Galveston, Texas, USA
| | - Gary DV Hankins
- Department of Obstetrics and Gynecology, The University of Texas Medical Branch Galveston, Texas, USA
| | - Chandra Yallampalli
- Department of Obstetrics and Gynecology, The University of Texas Medical Branch Galveston, Texas, USA
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Rosario FJ, Jansson N, Kanai Y, Prasad PD, Powell TL, Jansson T. Maternal protein restriction in the rat inhibits placental insulin, mTOR, and STAT3 signaling and down-regulates placental amino acid transporters. Endocrinology 2011; 152:1119-29. [PMID: 21285325 PMCID: PMC3858644 DOI: 10.1210/en.2010-1153] [Citation(s) in RCA: 133] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The mechanisms underlying reduced fetal growth in response to maternal protein restriction are not well established. Maternal levels of insulin, IGF-I, and leptin are decreased in rats fed a low protein (LP) diet. Because these hormones stimulate placental amino acid transporters in vitro, we hypothesized that maternal protein restriction inhibits placental leptin, insulin/IGF-I, and mammalian target of rapamycin signaling and down-regulates the expression and activity of placental amino acid transporters. Pregnant rats were fed either an isocaloric low protein (LP, 4% protein) or control diet (18% protein) and studied at gestational day (GD)15, GD19, or GD21 (term 23). At GD19 and GD21, placental expression of phosphorylated eukaryotic initiation factor 4E binding protein 1 (Thr-36/46 or Thr-70) and phosphorylated S6 ribosomal protein (Ser-235/236) was decreased in the LP group. In addition, placental expression of phosphorylated S6 kinase 1 (Thr-389), phosphorylated Akt (Thr-308), and phosphorylated signal transducer and activator of transcription 3 (Tyr-705) was reduced at GD21. In microvillous plasma membranes (MVM) isolated from placentas of LP animals, protein expression of the sodium-coupled neutral amino acid transporter (SNAT)2 and the large neutral amino acid transporters 1 and 2 was reduced at GD19 and GD21. MVM SNAT1 protein expression was reduced at GD21 in LP rats. SNAT4 and 4F2 heavy chain expression in MVM was unaltered. System A and L amino acid transporter activity was decreased in MVM from LP animals at GD19 and GD21. In conclusion, maternal protein restriction inhibits placental insulin, mammalian target of rapamycin signaling, and signal transducer and activator of transcription 3 signaling, which is associated with a down-regulation of placental amino acid transporters. We speculate that maternal endocrine and metabolic control of placental nutrient transport reduces fetal growth in response to protein restriction.
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Affiliation(s)
- Fredrick J Rosario
- Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center San Antonio, Mail Code 7836, 7703 Floyd Curl Drive, San Antonio, Texas 78229-3900, USA
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15
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Abstract
The rapid increase in the incidence of chronic non-communicable diseases over the past two decades cannot be explained solely by genetic and adult lifestyle factors. There is now considerable evidence that the fetal and early postnatal environment also strongly influences the risk of developing such diseases in later life. Human studies have shown that low birth weight is associated with an increased risk of CVD, type II diabetes, obesity and hypertension, although recent studies have shown that over-nutrition in early life can also increase susceptibility to future metabolic disease. These findings have been replicated in a variety of animal models, which have shown that both maternal under- and over-nutrition can induce persistent changes in gene expression and metabolism within the offspring. The mechanism by which the maternal nutritional environment induces such changes is beginning to be understood and involves the altered epigenetic regulation of specific genes. The demonstration of a role for altered epigenetic regulation of genes in the developmental induction of chronic diseases raises the possibility that nutritional or pharmaceutical interventions may be used to modify long-term cardio-metabolic disease risk and combat this rapid rise in chronic non-communicable diseases.
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Mühler MR, Clément O, Salomon LJ, Balvay D, Autret G, Vayssettes C, Cuénod CA, Siauve N. Maternofetal pharmacokinetics of a gadolinium chelate contrast agent in mice. Radiology 2010; 258:455-60. [PMID: 21045181 DOI: 10.1148/radiol.10100652] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To determine the maternofetal pharmacokinetics of gadoterate meglumine in mice during the first 48 hours following maternal intravenous injection of a high dose of 0.5 mmol of gadolinium per kilogram. MATERIALS AND METHODS All the studies complied with French law and the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health. Balb/C mice (n = 23) at 16 days of gestation were examined for 48 hours after maternal intravenous administration of 0.5 mmol gadolinium per kilogram of gadoterate meglumine. Gadolinium concentration in the placentas, fetuses, and amniotic fluid was determined by using mass spectrometry, and the total placental and fetal gadolinium content was calculated. Gadoterate meglumine half-life in the different compartments was estimated with one- and two-compartment models. Kruskal-Wallis and Wilcoxon signed-rank tests were used to compare the pharmacokinetic profiles. RESULTS Gadoterate meglumine passed the placental barrier, entering the fetuses and amniotic fluid before being redistributed back to the mother. The placental gadolinium concentration showed two-compartmental decay, with a first half-life of distribution of 47 minutes and a second half-life of elimination of 107 hours. The half-lives in the fetuses and amniotic fluid were, respectively, 4 and 5 hours and followed a monocompartmental model after the initial peak. The maximal gadolinium fetal concentration (31.8 nmol/g) was observed 30 minutes after injection, which corresponded to a total fetal content of 0.077% of the injected dose. CONCLUSION In mice, gadoterate meglumine, an extracellular nonspecific gadolinium chelate contrast medium, passed the placenta before being redistributed back to the mother, resulting in undetectable fetal concentrations after 48 hours.
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Affiliation(s)
- Matthias R Mühler
- INSERM, U970, Paris Cardiovascular Research Center-PARCC, Paris, France.
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17
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Abstract
The foundation for adult health is laid in utero and requires a healthy placenta. A common manifestation of abnormal placental development is impaired fetal growth. While placental pathology is the final common denominator in many cases of fetal growth restriction, a variety of discreet lesions have been described involving both the maternal and fetal circulations at their confluence in the placenta. Detailed examination of the placenta provides a means of elucidating the pathophysiology of poor fetal growth. This is an essential step in developing effective strategies for the prediction, prevention, and possible treatment of the growth restricted fetus.
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Affiliation(s)
- Jeffrey M Dicke
- Division of Maternal-Fetal Medicine and Ultrasound, Depart of Obstetrics and Gynecology, Washington University School of Medicine 660 South Euclid Ave, Maternity Building, 5th Floor, St Louis, Missouri 63110 USA
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18
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Maternal protein restriction with or without folic acid supplementation during pregnancy alters the hepatic transcriptome in adult male rats. Br J Nutr 2010; 103:1711-9. [PMID: 20211039 DOI: 10.1017/s0007114509993795] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Feeding pregnant rats a protein-restricted (PR) diet induces altered expression of candidate genes in the liver of the adult offspring, which can be prevented by supplementation of the PR diet with folic acid (PRF). We investigated the effect of maternal nutrition during pregnancy on the liver transcriptome in their adult male offspring. Pregnant rats were fed control, PR or PRF diets. Male offspring were killed on day 84. The liver transcriptome was analysed by microarray (six livers per maternal dietary group) followed by post hoc analysis of relative mRNA levels and gene ontology. These results were confirmed for selected genes by real-time RT-PCR. There were 311 genes that differed significantly ( >or= 1.5-fold change; P < 0.05) between PR offspring (222 increased) and control offspring, while 191 genes differed significantly between PRF offspring (forty-five increased) compared with offspring of control dams. There were sixteen genes that were significantly altered in both PR and PRF offspring compared with controls. Ion transport, developmental process, and response to reactive oxygen species (RROS) and steroid hormone response (SHR) ontologies were altered in PR offspring. Folic acid supplementation prevented changes within RROS and SHR response pathways, but not in ion transport or developmental process. There was no effect of maternal PR on mRNA expression of imprinted genes. Insulin 1 and Pleckstrin homology-like domain family A member 2 were increased significantly in PRF compared with PR offspring. The present findings show that the pattern of induced changes in the adult liver transcriptome were dependent on maternal protein and folic acid intakes during pregnancy.
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Arroyo JA, Brown LD, Galan HL. Placental mammalian target of rapamycin and related signaling pathways in an ovine model of intrauterine growth restriction. Am J Obstet Gynecol 2009; 201:616.e1-7. [PMID: 19800600 DOI: 10.1016/j.ajog.2009.07.031] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2009] [Revised: 06/13/2009] [Accepted: 07/14/2009] [Indexed: 12/21/2022]
Abstract
OBJECTIVE Both phosphorylated (p) mammalian target of rapamycin (mTOR) and protein S6 kinase 1 (p70S6K) are known to regulate protein synthesis and are affected during intrauterine growth restriction (IUGR). We studied the mTOR pathway during hyperthermia (HT)-induced IUGR in sheep. STUDY DESIGN Beginning at 40 days gestational age, 4 ewes were exposed to HT for 55 days and 4 were exposed for 80 days to induce IUGR. Western blot analyses were performed for mTOR, p70S6K, 4E-binding protein 1, extracellularly regulated kinase (ERK), and AKT. RESULTS HT animals showed: smaller fetuses and placentas near term; reduced placental weight at midgestation; increased p-mTOR, p-ERK, and p-AKT; decreased p70S6K in the near-term cotyledons; decreased p- p70S6K; and increased p-ERK in the caruncles (maternal) near term. CONCLUSION Near-term IUGR ovine cotyledons showed up-regulation of p-mTOR, whereas p70S6K was decreased. This suggests that the changes in placental mTOR signaling proteins could be driven by the fetal stress observed near term in this model of IUGR.
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Affiliation(s)
- Juan A Arroyo
- Division of Perinatal Medicine, Department of Obstetrics and Gynecology, University of Colorado Denver and Health Sciences Center, Aurora, CO 80045, USA.
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20
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Hua X, Zhu LP, Li R, Zhong H, Xue YF, Chen ZH. Effects of Diagnostic Contrast-Enhanced Ultrasound on Permeability of Placental Barrier: A Primary Study. Placenta 2009; 30:780-4. [DOI: 10.1016/j.placenta.2009.06.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Revised: 06/24/2009] [Accepted: 06/25/2009] [Indexed: 11/16/2022]
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21
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López Ramón Y Cajal C, Ocampo Martínez R, Couceiro Naveira E, Martínez M. Amino acids in amniotic fluid in the 15th–16thweeks of gestation and preterm labor. J Matern Fetal Neonatal Med 2009; 20:225-31. [PMID: 17437224 DOI: 10.1080/14767050601134660] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
OBJECTIVE To investigate amino acids in amniotic fluid collected at the time of genetic amniocentesis. METHODS We analyzed 128 fluids from the 15(th) week of gestation and 53 from the 16(th) week of gestation from normal pregnancies, and eight in the 15(th) week and seven in the 16(th) week from pregnancies that lead to preterm deliveries. We calculated the mean values for each week and the ratios between each pair of amino acids. The data for both groups (normal and preterm delivery) were compared. RESULTS The most abundant amino acid in both groups was alanine. The comparisons of the groups showed significant differences for isoleucine in the 15(th) gestational week (p<0.05). Some amino acids had different evolutions between both gestational ages on comparing the normal group and preterm group. Eighteen ratios in the 15(th) week showed significant differences (mainly in the ratios of arginine and taurine), and three in the 16(th) week. CONCLUSIONS The amino acid profiles in amniotic fluid, particularly in the 15(th) week of gestation, showed differences in the pregnancies that lead to preterm delivery.
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22
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Renaud SJ, Graham CH. The Role of Macrophages in Utero-placental Interactions During Normal and Pathological Pregnancy. Immunol Invest 2009; 37:535-64. [DOI: 10.1080/08820130802191375] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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23
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Jansson T, Powell TL. Role of the placenta in fetal programming: underlying mechanisms and potential interventional approaches. Clin Sci (Lond) 2007; 113:1-13. [PMID: 17536998 DOI: 10.1042/cs20060339] [Citation(s) in RCA: 358] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Adverse influences during fetal life alter the structure and function of distinct cells, organ systems or homoeostatic pathways, thereby ‘programming’ the individual for an increased risk of developing cardiovascular disease and diabetes in adult life. Fetal programming can be caused by a number of different perturbations in the maternal compartment, such as altered maternal nutrition and reduced utero–placental blood flow; however, the underlying mechanisms remain to be fully established. Perturbations in the maternal environment must be transmitted across the placenta in order to affect the fetus. Here, we review recent insights into how the placenta responds to changes in the maternal environment and discuss possible mechanisms by which the placenta mediates fetal programming. In IUGR (intrauterine growth restriction) pregnancies, the increased placental vascular resistance subjects the fetal heart to increased work load, representing a possible direct link between altered placental structure and fetal programming of cardiovascular disease. A decreased activity of placental 11β-HSD-2 (type 2 isoform of 11β-hydroxysteroid dehydrogenase) activity can increase fetal exposure to maternal cortisol, which programmes the fetus for later hypertension and metabolic disease. The placenta appears to function as a nutrient sensor regulating nutrient transport according to the ability of the maternal supply line to deliver nutrients. By directly regulating fetal nutrient supply and fetal growth, the placenta plays a central role in fetal programming. Furthermore, perturbations in the maternal compartment may affect the methylation status of placental genes and increase placental oxidative/nitrative stress, resulting in changes in placental function. Intervention strategies targeting the placenta in order to prevent or alleviate altered fetal growth and/or fetal programming include altering placental growth and nutrient transport by maternally administered IGFs (insulin-like growth factors) and altering maternal levels of methyl donors.
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Affiliation(s)
- Thomas Jansson
- Department of Obstetrics and Gynecology, College of Medicine, University of Cincinnati, Cincinnati, OH 45267, USA.
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24
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Abstract
PURPOSE OF REVIEW Modern consumer needs have stimulated a vast expansion in the dietary supplement market, in an attempt to improve general well being and prevent, rather than cure, disease. Isoflavones form a large part of this market. Their oestrogenic properties are still largely unknown and must be thoroughly researched to ensure they cause no adverse effects, particularly on hormone-dependent reproductive physiology. RECENT FINDINGS As a result of the increasing availability of phytoestrogens, research into their actions now covers a very wide field, many of which impact on reproductive potential. Time of exposure is crucial, as is interaction with other dietary components. Their putative role as chemoprotective agents has been expanded in recent years which may have an indirect impact on fertility by decreasing mortality rates in both men and women. SUMMARY Phytoestrogens are still a current research topic in reproduction and fertility. Genistein is a putative therapeutic tool in cancer treatment although this must be considered along with evidence that it may cause DNA damage in sperm, depending on the concentration. The effects of phytoestrogen in the body are not limited to oestrogenic action. Much more epidemiological data are required to interpret current molecular studies, and those of previous years.
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Roos S, Jansson N, Palmberg I, Säljö K, Powell TL, Jansson T. Mammalian target of rapamycin in the human placenta regulates leucine transport and is down-regulated in restricted fetal growth. J Physiol 2007; 582:449-59. [PMID: 17463046 PMCID: PMC2075295 DOI: 10.1113/jphysiol.2007.129676] [Citation(s) in RCA: 200] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Pathological fetal growth is associated with perinatal morbidity and the development of diabetes and cardiovascular disease later in life. Placental nutrient transport is a primary determinant of fetal growth. In human intrauterine growth restriction (IUGR) the activity of key placental amino acid transporters, such as systems A and L, is decreased. However the mechanisms regulating placental nutrient transporters are poorly understood. We tested the hypothesis that the mammalian target of rapamycin (mTOR) signalling pathway regulates amino acid transport in the human placenta and that the activity of the placental mTOR pathway is reduced in IUGR. Using immunohistochemistry and culture of trophoblast cells, we show for the first time that the mTOR protein is expressed in the transporting epithelium of the human placenta. We further demonstrate that placental mTOR regulates activity of the l-amino acid transporter, but not system A or taurine transporters, by determining the mediated uptake of isotope-labelled leucine, methylaminoisobutyric acid and taurine in primary villous fragments after inhibition of mTOR using rapamycin. The protein expression of placental phospho-S6K1 (Thr-389), a measure of the activity of the mTOR signalling pathway, was markedly reduced in placentas obtained from pregnancies complicated by IUGR. These data identify mTOR as an important regulator of placental amino acid transport, and provide a mechanism for the changes in placental leucine transport in IUGR previously demonstrated in humans. We propose that mTOR functions as a placental nutrient sensor, matching fetal growth with maternal nutrient availability by regulating placental nutrient transport.
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Affiliation(s)
- Sara Roos
- Perinatal Center, Department of Physiology, Institute of Neuroscience and Physiology, University of Gothenburg, PO Box 432, SE-405 30 Gothenburg, Sweden.
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Ericsson A, Säljö K, Sjöstrand E, Jansson N, Prasad PD, Powell TL, Jansson T. Brief hyperglycaemia in the early pregnant rat increases fetal weight at term by stimulating placental growth and affecting placental nutrient transport. J Physiol 2007; 581:1323-32. [PMID: 17430988 PMCID: PMC2170823 DOI: 10.1113/jphysiol.2007.131185] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
In pregnant women with type 1 diabetes, suboptimal glucose control in the first trimester is a strong predictor for giving birth to a large fetus. However, the mechanisms underlying this association are unknown. We hypothesized that transient hyperglycaemia in early pregnancy results in (1) increased placental growth and (2) an up-regulation of placental nutrient transport capacity, which leads to fetal overgrowth at term. In order to test this hypothesis, pregnant rats were given intraperitoneal injections of glucose (2 g kg(-1), resulting in a 50-100% increase in blood glucose level during 90 min) or saline (control) in either early or late gestation using four different protocols: one single injection on gestational day (GD) 10 (n=5), three injections on GD 10 (n=8-9), six injections on GD 10 and 11 (n=9-11) or three injections on GD 19 (n=7-8). Multiple injections were given approximately 4 h apart. Subsequently, animals were studied on GD 21. Three glucose injections in early pregnancy significantly increased placental weight by 10%, whereas fetal weight was found to be increased at term in response to both three (9% increase in fetal weight, P<0.05) and six glucose injections (7%, P=0.05) in early gestation. A single glucose injection on GD 10 or three injections of glucose on GD 19 had no effect on placental or fetal growth. In groups where a change in feto-placental growth was observed, we measured placental system A and glucose transport activity in the awake animals on GD 21 and placental expression of the glucose and amino acid transporters GLUT1, GLUT3, SNAT2 (system A), LAT1 and LAT 2 (system L). Placental system A transport at term was down-regulated by six glucose injections in early pregnancy (by -33%, P<0.05), whereas placental mRNA and protein levels were unchanged. No long-term alterations in maternal metabolic status were detected. In conclusion, we demonstrate that transient hyperglycaemia in early pregnancy is sufficient to increase fetal weight close to term. In contrast, brief hyperglycaemia in late pregnancy did not stimulate fetal growth. Increased fetal growth may be explained by a larger placenta, which would allow for more nutrients to be transferred to the fetus. These data suggest that maternal metabolic control in early pregnancy is an important determinant for feto-placental growth and placental function throughout the remainder of gestation. We speculate that maternal metabolism in early pregnancy represents a key environmental cue to which the placenta responds in order to match fetal growth rate with the available resources of the mother.
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MESH Headings
- Amino Acid Transport System A
- Amino Acid Transport System y+/metabolism
- Amino Acid Transport Systems/metabolism
- Amino Acid Transport Systems, Neutral/genetics
- Amino Acid Transport Systems, Neutral/metabolism
- Animals
- Blood Glucose/metabolism
- Diabetes, Gestational/blood
- Diabetes, Gestational/chemically induced
- Diabetes, Gestational/metabolism
- Diabetes, Gestational/pathology
- Disease Models, Animal
- Female
- Fetal Nutrition Disorders/blood
- Fetal Nutrition Disorders/etiology
- Fetal Nutrition Disorders/metabolism
- Fetal Nutrition Disorders/pathology
- Fetal Weight
- Fusion Regulatory Protein 1, Light Chains/metabolism
- Gestational Age
- Glucose
- Glucose Transport Proteins, Facilitative/genetics
- Glucose Transport Proteins, Facilitative/metabolism
- Glucose Transporter Type 1/metabolism
- Glucose Transporter Type 3/metabolism
- Hyperglycemia/blood
- Hyperglycemia/chemically induced
- Hyperglycemia/complications
- Hyperglycemia/metabolism
- Hyperglycemia/pathology
- Insulin/blood
- Large Neutral Amino Acid-Transporter 1/metabolism
- Maternal-Fetal Exchange
- Organ Size
- Placenta/metabolism
- Placenta/pathology
- Pregnancy
- RNA, Messenger/metabolism
- Rats
- Rats, Sprague-Dawley
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Affiliation(s)
- Anette Ericsson
- Perinatal Center, Institute of Neuroscience and Physiology, Gothenburg University, Box 432, s-405 30 Gothenburg, Sweden.
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Jansson N, Pettersson J, Haafiz A, Ericsson A, Palmberg I, Tranberg M, Ganapathy V, Powell TL, Jansson T. Down-regulation of placental transport of amino acids precedes the development of intrauterine growth restriction in rats fed a low protein diet. J Physiol 2007; 576:935-46. [PMID: 16916910 PMCID: PMC1892642 DOI: 10.1113/jphysiol.2006.116509] [Citation(s) in RCA: 142] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Intrauterine growth restriction (IUGR) represents an important risk factor for perinatal complications and for adult disease. IUGR is associated with a down-regulation of placental amino acid transporters; however, whether these changes are primary events directly contributing to IUGR or a secondary consequence is unknown. We investigated the time course of changes in placental and fetal growth, placental nutrient transport in vivo and the expression of placental nutrient transporters in pregnant rats subjected to protein malnutrition, a model for IUGR. Pregnant rats were given either a low protein (LP) diet (n = 64) or an isocaloric control diet (n = 66) throughout pregnancy. Maternal insulin, leptin and IGF-I levels decreased, whereas maternal amino acid concentrations increased moderately in response to the LP diet. Fetal and placental weights in the LP group were unaltered compared to control diet at gestational day (GD) 15, 18 and 19 but significantly reduced at GD 21. Placental system A transport activity was reduced at GD 19 and 21 in response to a low protein diet. Placental protein expression of SNAT2 was decreased at GD 21. In conclusion, placental amino acid transport is down-regulated prior to the development of IUGR, suggesting that these placental transport changes are a cause, rather than a consequence, of IUGR. Reduced maternal levels of insulin, leptin and IGF-1 may link maternal protein malnutrition to reduced fetal growth by down-regulation of key placental amino acid transporters.
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Affiliation(s)
- Nina Jansson
- Perinatal Center, Institute of Neuroscience and Physiology, Göteborg University, Sweden.
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Salomon LJ, Siauve N, Taillieu F, Balvay D, Vayssettes C, Frija G, Ville Y, Cuénod CA, Clément O. In Vivo Dynamic MRI Measurement of the Noradrenaline-induced Reduction in Placental Blood Flow in Mice. Placenta 2006; 27:1007-13. [PMID: 16316684 DOI: 10.1016/j.placenta.2005.10.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2005] [Revised: 10/04/2005] [Accepted: 10/18/2005] [Indexed: 11/19/2022]
Abstract
PURPOSE We developed a new model for in vivo placental perfusion measurements based on dynamic MRI in mice. As noradrenaline has been implicated in the pathogenesis of preeclampsia, we examined whether it reduced placental perfusion in mice, and whether such a reduction could be detected with our MRI model. MATERIALS AND METHODS Mice at 16 days of gestation were injected intramuscularly with saline or noradrenaline solution. A conventional gadolinium chelate was then injected IV, and a single-slice T1-weighed 2D Fast SPGR sequence was acquired for 200 s. Signal intensity was measured on all the images and converted into contrast agent tissue concentrations in the maternal left ventricle (input function) and placentas. A one-compartment model was developed using compartmental and numerical modeling software. Mean blood flow (F) was calculated from a transfer constant. RESULTS Twenty-six mice were studied, yielding a total of 55 MRI measurements of placental perfusion (29 in the control group and 26 in the noradrenaline group). Mean placental blood flow (F) was significantly lower in the noradrenaline group (0.72+/-0.84 ml/min/g of placenta) than in the control group (1.26+/-0.54 ml/min/g of placenta). CONCLUSION Noradrenaline reduces placental perfusion in mice. Our MRI dynamic model might be useful for detecting and investigating abnormal placental blood flow, thereby avoiding the need for invasive procedures and animal sacrifice.
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Affiliation(s)
- L J Salomon
- Faculté de Médecine, Laboratoire de Recherche en Imagerie, Faculté de médecine Necker Enfants Malades, Université Paris Descartes, Paris, France.
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Abstract
Fetal programming occurs when the normal pattern of fetal development is disrupted by an abnormal stimulus or 'insult' applied at a critical point in in utero development. This then leads to an effect, for example diabetes or hypertension, which manifests itself in adult life. As the placenta is the regulator of nutrient composition and supply from mother to fetus and the source of hormonal signals that affect maternal and fetal metabolism, appropriate development of the placenta is crucial to normal fetal development. Placental function evolves in a carefully orchestrated developmental cascade throughout gestation. Disruption of this cascade can lead to abnormal development of the placental vasculature or of the trophoblast. Timing of a developmental 'insult' will be critical in consequent placental function and hence programming of the fetus. The 'insults' that alter placental development include hypoxia and abnormal maternal nutrient status, to which the placenta may adapt by alterations in transporter expression and activity to maintain fetal growth or by epigenetic regulation of placental gene expression. Hypoxia is physiological for organogenesis and placental tissue normally exists in a relatively hypoxic environment, but intrauterine growth restriction (IUGR) and pre-eclampsia are associated with a greater degree of trophoblast hypoxia. The metabolic activity of placental mitochondria leads to oxidative stress even in normal pregnancy which is exacerbated further in IUGR, diabetic and pre-eclamptic pregnancies and may also give nitrative stress known to lead to covalent modification and hence altered activity of proteins. Hypoxia, oxidative and nitrative stress all alter placenta development and may be a general underlying mechanism that links altered placental function to fetal programming.
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Affiliation(s)
- Leslie Myatt
- Department of Obstetrics and Gynecology, University of Cincinnati, College of Medicine, PO Box 670526, Cincinnati, OH 45267, USA.
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Salomon LJ, Siauve N, Taillieu F, Balvay D, Clément O, Vayssettes C, Frija G, Ville Y, Cuénod CA. L’IRM fonctionnelle pour l’étude de la fonction placentaire. ACTA ACUST UNITED AC 2005; 34:666-73. [PMID: 16270004 DOI: 10.1016/s0368-2315(05)82899-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Placental insufficiency, a process due to either poor placental perfusion or permeability, may lead to progressive deterioration in placental function and materno-fetal morbidity. Advances in MR contrast media pharmacokinetic studies of transit through tissues and dynamic MRI allow to characterize organs microcirculation in vivo. Placental function assessment might be achieved using analysis of dynamic contrast enhanced MRI of tracers. A murine model of placental assessment has been constructed. Herein, principles, results and limitations of such techniques are discussed as well as their potential interest and weaknesses in humans.
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Affiliation(s)
- L-J Salomon
- Laboratoire de Recherche en Imagerie, Paris V, Faculté de Médecine Necker
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31
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Salomon LJ, Siauve N, Balvay D, Cuénod CA, Vayssettes C, Luciani A, Frija G, Ville Y, Clément O. Placental Perfusion MR Imaging with Contrast Agents in a Mouse Model. Radiology 2005; 235:73-80. [PMID: 15695621 DOI: 10.1148/radiol.2351040192] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To quantitatively analyze placental perfusion by using magnetic resonance (MR) imaging with contrast agents in a mouse model. MATERIALS AND METHODS Study was conducted according to French law and in full compliance with National Institutes of Health recommendations for animal care. Thirty-six pregnant Balb/c mice at 16 days of gestation were injected intravenously with either a conventional or macromolecular gadolinium chelate, and 1.5-T single-section T1-weighted two-dimensional fast spoiled gradient-echo sequential MR imaging was then performed for 14 minutes. Images were analyzed qualitatively, and parametric map analysis was performed in the resultant 25 mice included in the study. Signal intensity was measured in maternal left ventricle (input function), placenta, and fetus on all images. After converting signal intensity into contrast agent tissue concentrations, a three-compartment model was developed with compartmental and numeric modeling software. Placental perfusion was calculated for conventional (n = 12) and macromolecular (n = 13) gadolinium chelates. Finally, placental and fetal gadolinium concentrations were assayed by means of atomic emission spectrophotometry (n = 15). Perfusion values and placental and fetal gadolinium concentrations for conventional and macromolecular chelates were compared by using an unpaired t test. RESULTS Based on a constant transfer parameter, estimated placental perfusion did not differ between procedures with conventional and macromolecular gadolinium chelates (0.99 mL/min/g +/- 0.5 [standard deviation] and 1.28 mL/min/g +/- 0.6, respectively, P = .22). Likewise, mean placental gadolinium concentrations did not differ after injection of conventional and macromolecular chelates. In contrast, mean fetal gadolinium concentration was 9.83 micromol/L after conventional chelate injection and below detection limit after macromolecular chelate injection. CONCLUSION Placental perfusion can be calculated by using dynamic contrast-enhanced MR imaging, as shown in this mouse model.
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Affiliation(s)
- Laurent J Salomon
- Laboratoire de Recherche en Imagerie, INSERM U494, Faculté de Médecine Necker, Université Paris 5, 156 rue de Vaugirard, 75015 Paris, France
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32
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Abstract
Regulation of fetal growth is multifactorial and complex. Diverse factors, including intrinsic fetal conditions as well as maternal and environmental factors, can lead to intrauterine growth restriction (IUGR). The interaction of these factors governs the partitioning of nutrients and rate of fetal cellular proliferation and maturation. Although IUGR is probably a physiologic adaptive response to various stimuli, it is associated with distinct short- and long-term morbidities. Immediate morbidities include those associated with prematurity and inadequate nutrient reserve, while childhood morbidities relate to impaired maturation and disrupted organ development. Potential long-term effects of IUGR are debated and explained by the fetal programming hypothesis. In formulating a comprehensive approach to the management and follow-up of the growth-restricted fetus and infant, physicians should take into consideration the etiology, timing, and severity of IUGR. In addition, they should be cognizant of the immediate perinatal response of the growth-restricted infant as well as the childhood and long-term associated morbidities. A multi disciplinary approach is imperative, including early recognition and obstetrical management of IUGR, assessment of the growth-restricted newborn in the delivery room, possible monitoring in the neonatal intensive care unit, and appropriate pediatric follow-up. Future research is necessary to establish effective preventive, diagnostic, and therapeutic strategies for IUGR, perhaps affecting the health of future generations.
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Affiliation(s)
- Dara Brodsky
- Beth Israel Deaconess Medical Center and Children's Hospital, Harvard Medical School, Department of Newborn Medicine, Boston, MA 02215, USA.
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Ericsson A, Hamark B, Powell TL, Jansson T. Glucose transporter isoform 4 is expressed in the syncytiotrophoblast of first trimester human placenta. Hum Reprod 2005; 20:521-30. [PMID: 15528266 DOI: 10.1093/humrep/deh596] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Placental glucose transport mechanisms in early pregnancy are poorly understood. The aims of this study were to investigate the expression of glucose transporter (GLUT) isoforms 1, 3 and 4 in first trimester villous tissue, to assess the effects of insulin on glucose uptake and compare them with term. METHODS The expression of GLUT isoforms was investigated using immunohistochemistry, Western blot and reverse transcription (RT)-PCR in trophoblast tissue from terminations at 6-13 weeks gestation and term. The effects of insulin (300 ng/ml, 1 h) on glucose uptake were studied in villous fragments. RESULTS In the first trimester, GLUT1 and GLUT3 were present in the microvillous membrane and the cytotrophoblast, and GLUT4 in perinuclear membranes in the cytosol of the syncytiotrophoblast (ST). GLUT4 protein (48 kDa) and mRNA were identified in trophoblast homogenates. Whereas GLUT1 was expressed abundantly in term placenta, the expression of GLUT3 and 4 was markedly lower at term compared with first trimester. Insulin increased glucose uptake by 182% (n=6, P<0.05) in first trimester fragments, but not in term fragments. CONCLUSIONS The insulin-regulatable GLUT4 is expressed in the cytosol of first trimester ST compatible with a role for GLUT4 in placental glucose transport in early pregnancy. The placental expression pattern of GLUT isoforms in early pregnancy is distinct from that later in pregnancy.
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Affiliation(s)
- A Ericsson
- Department of Physiology and Pharmacology, Perinatal Center, Göteborg University, 405 30 Göteborg, Sweden.
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Maggio L, Zuppa AA, Sawatzki G, Valsasina R, Schubert W, Tortorolo G. Higher urinary excretion of essential amino acids in preterm infants fed protein hydrolysates. Acta Paediatr 2005; 94:75-84. [PMID: 15858965 DOI: 10.1111/j.1651-2227.2005.tb01792.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
AIM Protein hydrolysates have been introduced in preterm formulae, but it is not clear whether they are needed for the feeding of preterm infants. We designed a randomized, controlled trial to test the effects of a preterm formula with hydrolysed cow's milk proteins on short-term growth and urinary and plasma amino acids levels. METHODS Infants with a birthweight < or = 1750 g and gestational age < or = 34 wk fed a conventional preterm infant formula (formula B) or a hydrolysed formula (formula A). Weight was measured daily; length, head circumference, mid-arm circumference and total skinfold thickness were measured weekly. Blood and urine were analysed for amino acid concentrations at start, 14 and 28 d. RESULTS Twenty-one infants met the criteria for randomization. The daily feeding volumes were: formula A 172.8 +/- 5.6 vs formula B 170.1 +/- 2.8 ml/kg/d. Infants fed with formula A showed slower weight gain (17.4 +/- 3.4 vs 20.5 +/- 3.3 g/kg/d; p = 0.045) and lower mean change in Z-scores for weight (-0.18 +/- 0.16 vs 0.00 +/- 0.09; p = 0.009) and for head circumference (-0.06 +/- 0.13 vs 0.06 +/- 0.13; p = 0.049). After 14 d, infants receiving formula A had statistically significant higher urinary levels of essential amino acids compared to infants receiving formula B. CONCLUSION Our results support the hypothesis of less nutritional value of hydrolysed versus conventional preterm formulae. Higher renal excretion of essential amino acids may be one of the mechanisms involved. These findings must be confirmed by further studies with larger sample sizes and protein hydrolysates with different degrees of hydrolysis.
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Affiliation(s)
- L Maggio
- Division of Neonatology, Department of Paediatrics, Catholic University of the Sacred Heart, Rome, Italy.
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Roos S, Powell TL, Jansson T. Human placental taurine transporter in uncomplicated and IUGR pregnancies: cellular localization, protein expression, and regulation. Am J Physiol Regul Integr Comp Physiol 2004; 287:R886-93. [PMID: 15166008 DOI: 10.1152/ajpregu.00232.2004] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Transplacental transfer is the fetus' primary source of taurine, an essential amino acid during fetal life. In intrauterine growth restriction (IUGR), placental transport capacity of taurine is reduced and fetal taurine levels are decreased. We characterized the protein expression of the taurine transporter (TAUT) in human placenta using immunocytochemistry and Western blotting, tested the hypothesis that placental protein expression of TAUT is reduced in IUGR, and investigated TAUT regulation by measuring the Na(+)-dependent taurine uptake in primary villous fragments after 1 h of incubation with different effectors. TAUT was primarily localized in the syncytiotrophoblast microvillous plasma membrane (MVM). TAUT was detected as a single 70-kDa band, and MVM TAUT expression was unaltered in IUGR. The PKC activator PMA and the nitric oxide (NO) donor 3-morpholinosydnonimine decreased TAUT activity (P < 0.05, n = 7-15). However, none of the tested hormones, e.g., leptin and growth hormone, altered TAUT activity significantly. PKC activity measured in MVM from control and IUGR placentas was not different. In conclusion, syncytiotrophoblast TAUT is strongly polarized to the maternal-facing plasma membrane. MVM TAUT expression is unaltered in IUGR, suggesting that the reduced MVM taurine transport in IUGR is due to changes in transporter activity. NO release downregulates placental TAUT activity, and it has previously been shown that IUGR is associated with increased fetoplacental NO levels. NO may therefore play an important role in downregulating MVM TAUT activity in IUGR.
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Affiliation(s)
- S Roos
- Perinatal Center, Dept. of Physiology and Pharmacology, Göteborg Univ., PO Box 432, S-405 30 Göteborg, Sweden.
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Abstract
Intrauterine growth restriction (IUGR) represents an important risk factor for perinatal complications and for adult disease. IUGR is associated with a down‐regulation of placental amino acid transporters; however, whether these changes are primary events directly contributing to IUGR or a secondary consequence is unknown. We investigated the time course of changes in placental and fetal growth, placental nutrient transport in vivo and the expression of placental nutrient transporters in pregnant rats subjected to protein malnutrition, a model for IUGR. Pregnant rats were given either a low protein (LP) diet (n= 64) or an isocaloric control diet (n= 66) throughout pregnancy. Maternal insulin, leptin and IGF‐I levels decreased, whereas maternal amino acid concentrations increased moderately in response to the LP diet. Fetal and placental weights in the LP group were unaltered compared to control diet at gestational day (GD) 15, 18 and 19 but significantly reduced at GD 21. Placental system A transport activity was reduced at GD 19 and 21 in response to a low protein diet. Placental protein expression of SNAT2 was decreased at GD 21. In conclusion, placental amino acid transport is down‐regulated prior to the development of IUGR, suggesting that these placental transport changes are a cause, rather than a consequence, of IUGR. Reduced maternal levels of insulin, leptin and IGF‐1 may link maternal protein malnutrition to reduced fetal growth by down‐regulation of key placental amino acid transporters.
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Abstract
Intrahepatic cholestasis of pregnancy (ICP) affects about 0.7% of deliveries in Britain. It is regarded as a benign condition for the mother but is associated with increased fetal mortality in late pregnancy and early delivery is advised. Ursodeoxycholic acid (UDCA) treatment is beneficial to the mother and does not appear to harm the fetus. ICP is often regarded as a disease of the maternal liver already made 'cholestatic' by high levels of circulating progesterone. We propose that ICP should be considered as a feto-maternal disease involving complex interactions between maternal and fetal bile acid metabolism across the placenta. During the late stages of gestation, when there is a rise in fetal and maternal bile acid levels, the placenta may fail to render potentially hepatotoxic bile acids water soluble and hence excretable. This might cause a vicious cycle leading to further cholestasis in the maternal liver already challenged by progesterone.
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Abstract
Amino acid transport across the human placenta is active, mediated by specific transporters in syncytiotrophoblast plasma membranes. Using functional criteria such as substrate specificity and sodium dependence, approximately 15 transport systems have been identified in the human placenta. Recently, the area of molecular biology of amino acid transporters has evolved rapidly and at least 25 cDNA clones coding for mammalian amino acid transporters or transporter subunits have been identified. The primary objective of this review is to integrate the available functional data on placental amino acid transport systems with recent molecular information on mammalian amino acid transporters. Furthermore, models for the mechanisms for net materno-fetal transfer of amino acids are discussed. Finally, the evidence to suggest that alterations in placental amino acid transport systems may play a crucial role in the regulation of fetal growth are presented briefly.
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Affiliation(s)
- T Jansson
- Perinatal Center, Department of Physiology and Pharmacology, Göteborg University, s-405 30 Göteborg, Sweden
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