During normal placental development, a primitive vascular network develops through vasculogenesis and angiogenesis, and is then remodelled through maturation and regression. The mechanism behind this regression is unknown, but data from other systems suggests that it could be due to an endothelial-mesenchymal transition (EndMT). If this is the case, then dysregulated EndMT could lead to increased vascular regression, which could result in placental hypovascularisation. As the placental vasculature is the area of exchange between maternal and fetal circulations, a reduction in its surface area could result in fetal growth restriction (FGR). The hypothesis of this thesis is that EndMT occurs during normal placental development, but is increased during FGR and contributes to placental hypovascularisation. A primary cell model consisting of endothelial and mesenchymal cells was isolated from human first trimester placental villous stroma. These cells were shown to lose CD31 mRNA (n = 1-3) and protein (n = 15) over 4 passages, with no loss of cell viability (n = 8). EndMT-associated transcription factors were also present in these cells at all 4 passages (n = 2-4). When cells were isolated from this mixed cell model based on their CD31-positivity and examined immediately after isolation, a small proportion also expressed αSMA (n = 5). Co-expression of endothelial and mesenchymal markers suggests that an EndMT was occurring. After 24 hours in culture, the proportion of these cells expressing αSMA increased (n = 5), and some cells co-expressed vWF and αSMA, while others lost their CD31-positivity, indicating that these cells had undergone EndMT. Cells isolated based on their CD31-positivity were treated with factors shown to inhibit EndMT in other systems. However, culture with 10µM SB431542 (TGFβ receptor inhibitor; n = 6), 10µM Dorsomorphin (BMP receptor inhibitor; n = 3), or 0.1µM PDGFR-β Tyrosine Kinase Inhibitor IV (n = 3) did not inhibit gain of αSMA by these cells. Culture on Matrigel in endothelial growth medium containing VEGF and FGF also failed to stabilise the endothelial phenotype (n = 3). The possibility that EndMT occurs in placenta in vivo was examined; genes associated with EndMT were shown to be present in placenta (n = 5), and there was limited evidence of CD31 or vWF co-expression with αSMA in tissue. Preliminary evidence was obtained to suggest that expression of EndMT-associated genes was altered in FGR placentas compared to normal. In summary, the data presented in this thesis demonstrate that an EndMT occurs in primary placental microvascular endothelial cells in vitro. Furthermore, these studies provide evidence to suggest that this transition also occurs in vivo and could be altered in placentas from pregnancies complicated by FGR.

Advanced maternal age (AMA) is defined as childbearing in mothers ≥35 years of age and is becoming increasingly prevalent in high income countries. AMA has been associated with increased risk of adverse pregnancy outcomes, particularly stillbirth. Although AMA mothers have higher rates of chromosomal abnormalities and maternal co-morbidities, AMA remains an independent risk factor for stillbirth. Despite these findings, the etiology behind this increased risk is unknown. We hypothesise that an altered maternal environment, including increased oxidative stress and inflammation, due to ageing causes placental dysfunction which increases AMA mothers’ vulnerability to stillbirth. A holistic approach was applied to investigate placental dysfunction in AMA. Firstly, a systematic review and meta-analysis comprehensively reviewed existing data on AMA and associated adverse pregnancy outcomes. Secondly, Manchester Advanced Maternal Age Study (MAMAS), a multi-centre prospective observational cohort study, was conducted to investigate risk factors for composite adverse pregnancy outcome (CAPO) in AMA. MAMAS utilised both uni- and multivariate analysis on demographic and clinical data, and measuring biomarkers of ageing and placental dysfunction by ELISA in maternal circulation during the third trimester of pregnancy. Utero-placental dysfunction was directly investigated in uncomplicated AMA pregnancies by quantifying placental morphology, placental nutrient transport capabilities and both placental and maternal uterine vascular responses. Finally, a C57BL/6J murine model of AMA was developed and characterised to further investigate maternal age on pregnancy outcome and the role of the placenta. In the meta-analysis, maternal age was linearly associated with increased risk of stillbirth and other adverse outcomes strongly associated with placental dysfunction (fetal growth restriction, preeclampsia and placental abruption). In MAMAS, smoking status and primiparity were predictive of CAPO. After adjustment, AMA mothers had an odd ratio of 2.05-3.43 of CAPO compared to 20-30 year old mothers. AMA mothers showed evidence of increased oxidative stress and pro-inflammatory bias. AMA mothers who suffered CAPO showed reduced placental endocrine capacity seen in placental dysfunction. Placentas from uneventful AMA pregnancies showed evidence of accelerated ageing and placental adaptation with increased nutrient transport, increased placental weight but reduced efficiency, and altered vascular function. AMA mice showed many similar aspects to human AMA with increased fetal loss, fetal growth restriction and increased placental size. These studies provide robust evidence for increased incidence of adverse pregnancy outcome due to placental dysfunction in pregnancies of women of AMA. This finding requires the appropriate recognition in a clinical context, with a greater focus on personalised obstetric care in an attempt to reduce stillbirth rates in this high risk population. By optimising antenatal and obstetric care for AMA mothers, we could reduce stillbirth rates by 4.7% - the population attributable risk due to AMA. These studies highlight key areas of future research that will further understanding into stillbirth risk in AMA pregnancy, test predictive models and test therapies and clinical care interventions an ultimately improve pregnancy outcome in mothers of AMA.

De nombreuses données indiquent qu’un petit poids à la naissance, résultant en partie d’une sous-nutrition materno-fœtale, est associé à une augmentation de la morbidité et de la mortalité durant la période néonatale, et conduit également à un risque accru de développer à l'âge adulte un syndrome métabolique (diabète de type 2, obésité, hypertension artérielle et dyslipidémie). Les mécanismes de cette programmation prénatale sont encore mal connus et impliqueraient plusieurs molécules et systèmes physiologiques distincts. De nombreuses études suggèrent que le placenta serait impliqué dans la programmations de ces pathologies métaboliques. En effet, celui-ci constitue un organe de communication entre la mère et son fœtus et participe à la régulation de l'homéostasie fœtale. En raison de la proportion croissante de femmes présentant des troubles de la nutrition durant la grossesse et en lien avec leurs répercussions potentielles chez la descendance, il est nécessaire de mieux comprendre les interactions entre l’alimentation maternelle et l’unité fœto-placentaire et d’identifier les mécanismes impliqués dans les altérations de la croissance fœtale. En conséquent, le placenta constitue un organe de choix pour étudier les interactions entre l’alimentation maternelle et le fœtus au cours de la grossesse. Durant cette thèse, nous avons tenté d’identifier de nouvelles voies moléculaires placentaires impliquées dans le contrôle de la croissance fœtale chez le rat, puis d'étudié l'expression de ces facteurs dans des placentas humains provenant de grossesses impliquant des anomalies de la croissance fœtale. Comme la malnutrition maternelle constitue une part importante dans l'étiologie de la restriction de croissance intra-utérine (RCIU), nous avons utilisé un modèle expérimental effectué chez le rat, qui consiste en une réduction (de 50% à 70%) de la ration alimentaire quotidienne maternelle durant la gestation. Ces régimes conduisent à des troubles de la croissance de l'unité fœto-placentaire révélés par des réductions drastiques du poids du placenta et des poids de naissance à terme. Afin d'identifier de nouvelles voies placentaires impliquées dans RCIU, nous avons utilisé deux méthodologies différentes: une approche protéomique et une évaluation de deux protéines récemment caractérisées.Premièrement, nous avons étudié le protéome placentaire chez le rat RCIU provenant de mères dénutris par une analyse protéomique (2D-PAGE et spectrométrie de masse). Cette stratégie nous a permis de découvrir de nouvelles voies modulées par le RCIU et, étonnamment, des modulations importantes ont été observées pour plusieurs protéines mitochondriales, suggérant un effet ciblé de la dénutrition sur ces organites. Par la suite, en utilisant diverses techniques d'analyses moléculaires, protéomiques et fonctionnelles, nous avons montré que ces organites élaborent une réponse adaptative à la restriction alimentaire maternelle qui pourrait avoir des conséquences sur la régulation de la croissance fœtale. Deuxièmement, nous avons étudié deux autres protéines atypiques: le brain-derived neurotrophic factor et l'hormone apéline. Nos résultats suggèrent que ces deux facteurs pourraient être impliqués, au niveau placentaire, dans le contrôle de la croissance fœtale à la fois chez le rat et chez l'homme. En conclusion, comme les techniques cliniques actuelles ne permettent pas de diagnostiquer avec précision un RCIU, nos résultats pourraient permettre une meilleure compréhension de la physiopathologie placentaire et permettre de développer de nouveaux marqueurs de diagnostique et/ou de traitement dans le but d'améliorer la croissance placentaire et fœtale en conditions pathologiques. / Growing evidences indicate that a small birthweight, resulting from maternal malnutrition or others prenatal alterations, is associated with an increased neonatal morbidity and mortality and may lead to higher propensity to develop a metabolic syndrome (including type 2 diabetes, obesity, hypertension and dyslipidemia) in adulthood. However, the physiopathological mechanisms acting in utero on the programming of the offspring's metabolic profile remain confused and may implicate numerous molecules and physiological systems. Several data suggest that the placental alterations may have long-lasting consequences and could thus contribute to the programming of adult metabolic diseases. The placenta is the primary means of communication and nutrient delivery to the fetus and is also involved in fetal homeostasis. Thus, the placenta may constitute an appropriate organ for investigating how differences in maternal food consumption are sensed by the fetus along the pregnancy. Because of the increasing proportion of women eating inadequately during pregnancy and because such nutritional disturbances may have huge repercussions on adult health of the offspring, we urgently have to better understand how the placenta elaborates adaptive responses to maternal food intake modulations. My PhD aimed at identifying new placental pathways implicated in fetal growth restriction in rat, and investigated in human placental samples, the expression of these factors in pregnancies with fetal growth disturbances.As maternal malnutrition constitutes an important part in the etiology of intrauterine growth restriction (IUGR), we used an experimental model performed in rats which consists of a reduction (from 50% to 70%) of the daily maternal food intake during the gestation. These regimens lead to profound growth disturbances of the feto-placental unit revealed by drastic reductions of both placental and birth weights at term. To identify new placental pathways implicated in IUGR, we have used two different strategies: a proteomic approach and the evaluation of two proteins recently characterized in the placenta.First, we investigated the placental proteome in IUGR rats from undernourished mothers using 2D-PAGE electrophoresis and mass spectrometry identification. This strategy allowed the discovery of new pathways modulated by IUGR. Surprisingly, major modulations were observed for several proteins localized in mitochondria, suggesting specific effects of maternal undernutrition on these organelles. Thereafter, using multiple molecular, proteomic and functional analyses, we have shown that these organelles develop adaptive responses to maternal nutrient restriction that may have functional consequences on the regulation of the fetal growth. Secondly, we studied two others atypical proteins: the brain-derived neurotrophic factor and the hormone apelin. Our findings suggest that both of these factors may be implicated in the control of fetal growth at the placental level in rat and putatively in human. As actual clinical methods do not permit to diagnose precisely fetal growth disturbances, our results may permit to better understand the placental physiological pathways implicated during these pathologies and could lead to the development of markers and/or treatments in order to improve both placental functions and fetal growth.

No description available.

Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 5 uppsatser.

Diss. (sammanfattning) Linköping : Linköpings universitet, 2007. / Härtill 4 uppsatser.

Objectif : Établir le profil psychosocial des femmes enceintes de l'Estrie et évaluer de façon préliminaire si ce profil diffère parmi les grossesses avec issues défavorables. Méthode. Cohorte prospective de 120 femmes enceintes, rencontrées à deux reprises (10-20 et 25-30 semaines), entre août 2004 et mars 2006. Il s'agit d'un questionnaire auto-administré des données démographiques, anthropométriques, des facteurs de risques biomédicaux, ainsi qu'un profil psychosocial comportant 6 dimensions: stress psychologique perçu, ennuis quotidiens, détresse psychologique, locus de contrôle, soutien social, traumatismes dans l'enfance. Les paramètres psychosociaux sont présentés en moyennes ou pourcentages. Le profil psychosocial est comparé entre les grossesses normales et anormales avec les tests t de Student ou le test de Mann Whitney, lorsque approprié. Résultats. Trente trois grossesses (27,5%) ont présenté des issues défavorables (prématurité, restriction de croissance intra-utérine, hypertension gestationnelle, diabète gestationnel). L'analyse du profil psychosocial révèle un score de stress psychologique perçu plus élevé entre 10-20 semaines chez les femmes avec issues défavorables de grossesse (score : 34,2 « 12,3 ; P < 0,01) et chez les femmes avec prématurité (score : 36,1 « 11,2 ; P < 0,02) comparativement à celui des femmes avec grossesses normales (score : 28,6 « 9,6). Par ailleurs, les 5 autres dimensions ne semblaient pas différentes selon les issues de grossesse. Conclusion. Ces résultats préliminaires suggèrent une piste possible reliant la perception de stress maternel durant la grossesse et certaines issues défavorables de grossesse, dont l'accouchement prématuré.

Background: Previous research suggests that vitamin D deficiency during pregnancy may be associated with suboptimal fetal growth, but direct evidence is lacking. Our objectives were 1) to develop a method for measurement of the fetal sphenoidal fontanelle area (FA) and femur volume (FV) using 3D ultrasound; 2) to create normal charts for FA and FV; and 3) to correlate FA and FV with maternal vitamin D concentration. Methods: FA measurement in 3D was evaluated in vitro and in vivo. Different segmentation methods for FV measurement were explored. A novel FV method was described which consists of three linear measurements and a volume equation; this was validated in vitro and also by comparing FV measured sonographically to the true volume assessed by computed tomography (CT), in 6 cases following pregnancy termination. A cohort of 868 uncomplicated pregnancies was selected on the basis of strict inclusion criteria; participants underwent serial ultrasound scans for FV and multilevel modeling was used for the creation of a “prescriptive” FV chart. Finally, a different cohort of 357 healthy pregnant women had serum vitamin D levels and FV ultrasound at 34 weeks gestation and dual emission x-ray absorptiometry (DEXA) of their neonates in order to investigate the prenatal determinants of fetal bone mass. Results: FA measurement was accurate in vitro, but unreliable in vivo and was therefore abandoned. A novel FV method had excellent agreement with CT and superior repeatability compared with segmentation-based methods. A normal FV chart was created and the regression equations for the median and percentile values were presented. Vitamin D demonstrated a significant correlation with FV. Conclusions: FV is a reliable sonographic marker of skeletal growth. Maternal vitamin D deficiency is associated with reduced FV. This finding has public health implications as reduced bone mass may increase the lifetime risk of osteoporosis, through fetal programming.

O objetivo deste estudo foi comparar a morbidade e a mortalidade entre prematuros tardios (34 a 36 semanas e 6 dias de idade gestacional ao nascimento) com e sem restrição do crescimento fetal (RCF). O estudo foi desenvolvido longitudinalmente, envolvendo gestantes que apresentaram parto prematuro, sendo 50 com RCF (Grupo I) e 36, sem RCF (Grupo II), no período de outubro de 2004 a outubro de 2006. Foram avaliados os seguintes resultados pós-natais: peso e idade gestacional (IG) ao nascimento, cesárea, Apgar de quinto minuto, pH do sangue da artéria umbilical ao nascimento, necessidade e tempo de intubação orotraqueal (IOT) e de internação na unidade de terapia intensiva neonatal (UTI). Foram também avaliados: síndrome do desconforto respiratório (SDR), sepse, plaquetopenia, hipoglicemia, hemorragia intracraniana (HIC), icterícia e necessidade de fototerapia, tempo de internação e ocorrência de óbito. Para análise estatística foram utilizados os testes de Qui-Quadrado, exato de Fisher e teste não paramétrico de Kruskal Wallis, adotado nível de significância de 5%. As idades gestacionais avaliadas foram semelhantes nos dois grupos, com média de 35,5 semanas. Observou-se, no grupo I, maior freqüência dos seguintes resultados pós-natais adversos: menor peso ao nascimento (p<0,001), maior incidência de cesárea (92% versus 25% do grupo II; p<0,0001), maior necessidade de internação em UTI (58% versus 33%; p=0,041), maior tempo de internação (p<0,001) e de internação em UTI neonatal (p<0,001), maior ocorrência de HIC (12% versus 0; p=0,037), maior ocorrência de hipoglicemia (p= 24% versus 6%; 0,047) e maior tempo de fototerapia (p=0,005). Os grupos não apresentaram diferenças nos índices de Apgar, pH de cordão, IOT, SDR, plaquetopenia, sepse e icterícia. Não houve casos de doença de membrana hialina, displasia broncopulmonar, hemorragia pulmonar ou óbito neonatal. Pode-se concluir que o grupo de prematuros tardios com RCF apresentou mais complicações neonatais do que o grupo sem RCF / The objective of this study was to compare neonatal morbidity and mortality between late-preterm infants (gestational age at birth: 34 to 36 weeks and 6 days) with and without fetal growth restriction (FGR). A longitudinal study was conducted between October 2004 and October 2006 involving 50 pregnant women with pre-term delivery associated with FGR (group I) and 36 women with spontaneous preterm delivery not associated with FGR (group II). The following postnatal outcomes were evaluated: weight and gestational age at birth, cesarean section rate, 5-minute Apgar score, umbilical artery pH at birth, and need for and duration of orotracheal intubation and hospitalization in the neonatal intensive care unit (NICU), as well as the presence of respiratory distress syndrome (RDS), sepsis, thrombocytopenia, hypoglycemia, intracranial hemorrhage (ICH) and jaundice, need for phototherapy, length of hospital stay, and occurrence of death. The chi-square test, Fishers exact test and nonparametric Kruskal-Wallis test were used for statistical analysis, adopting a level of significance of 5%. Gestational age was similar in groups I and II, with a mean of 35.5 weeks in both groups. A higher frequency of the following adverse postnatal outcomes was observed in group I: lower birth weight (p<0.001), higher incidence of cesarean section (92% versus 25% in group II; p<0.0001), greater need for NICU treatment (58% versus 33%; p=0.041), longer hospital (p<0.001) and NICU stay (p<0.001), higher frequency of ICH (12% versus 0; p=0.037) and hypoglycemia (24% versus 6%; p=0.047), and longer duration of phototherapy (p=0.005). No differences in Apgar scores, cord pH, orotracheal intubation, RDS, thrombocytopenia, sepsis, or jaundice were observed between groups. There were no cases of hyaline membrane disease, bronchopulmonary dysplasia, pulmonary hemorrhage, or neonatal death. In conclusion, the group of late-preterm infants with FGR presented more neonatal complications than the group without FGR

Wang, Xiao. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 32-37). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts also in Chinese.