La prématurité et la restriction de croissance fœtale (RCF) sont deux pathologies néonatales fréquentes, qui ont en commun des difficultés d'adaptation à la naissance, avec le développement d'une tubulopathie chez le prématuré, et le développement d'une hypertension artérielle (HTA) a l'âge adulte. L’objectif de ce travail était d’évaluer l'implication des voies de signalisation corticostéroïdes rénales dans la survenue de ces complications dans un modèle murin de prématurité induite par des lipopolysaccharides, et un modèle de RCF par exposition périnatale a la dexaméthasone. Dans ce travail nous avons montré que ces deux pathologies programment la survenue d’une HTA à l’âge adulte chez les mâles, associée à des altérations franches de la signalisation corticostéroïde rénale en période périnatale et une augmentation de la sensibilité rénale aux glucocorticoïdes à l’âge adulte. Dans le modèle de prématurité, nous avons identifié la transmission transgénérationelle d’anomalies de régulation de la pression artérielle chez les mâles jusqu’à la 3ème génération de souris, associée à une hypométhylation du promoteur de GILZ et une augmentation d’expression de GILZ. Notre étude a permis l’identification de potentiels mécanismes moléculaires impliqués dans la programmation fœtale de l’HTA, sur plusieurs générations, ce qui pourrait aboutir à une meilleure prise en charge des patients nés prématurés ou avec une RCF, et de leurs descendants. / Preterm birth and fetal growth restriction (IUGR) are prevalent neonatal diseases, which both induce poor perinatal adaptation, including the development of tubulopathy in premature infants, and the development of high blood pressure in adults. The objective of this work was to evaluate the involvement of renal corticosteroid signaling pathways in the development of these complications in a lipopolysaccharide-induced mouse model of preterm birth, and a dexamethasone-induced model of IUGR. In this work, we have shown that these two pathologies program the development of hypertension in former preterm and IUGR male mice, associated with strong alterations of renal corticosteroid signaling in the perinatal period, and an increase in renal sensitivity to glucocorticoids in adulthood. Moreover, we have identified a transgenerational inheritance of altered blood pressure regulation induced by preterm birth, in males, up to the 3rd generation of mice, associated with GILZ promoter hypomethylation and increased GILZ expression.Our study has identified potential molecular mechanisms involved in the fetal programming of hypertension, over several generations. These findings could facilitate better management of patients born prematurely

La restriction de croissance intra-utérine (RCIU) est une conséquence immédiate d’un environnement utérin défavorable qui prédispose les individus atteints à de plus grands risques de développer des maladies cardiométaboliques une fois adulte. L’environnement fœtal s’ajoute ainsi à l’hérédité, au sexe et au mode de vie comme facteur déterminant de la santé cardiométabolique. Afin de mieux comprendre les différents aspects de cette prédisposition, notre laboratoire a développé un modèle animal de RCIU asymétrique recréant une diminution de la perfusion placentaire. La caractérisation des animaux a mis en évidence des différences dans la physiologie cardiovasculaire des individus adultes avec des dissemblances selon le sexe, ainsi qu’une différence dans l’expression de plusieurs gènes impliqués dans le métabolisme lipidique chez le fœtus. A partir de ces données, nous émettons l’hypothèse que le cœur fœtal RCIU subit une reprogrammation métabolique, conséquence du stress causé par l’environnement fœtal défavorable. Nous nous attendons aussi à une régulation différente du métabolisme entre les mâles et les femelles. Pour répondre à cette hypothèse, nous avons tout d’abord déterminé la contribution du métabolisme lipidique dans les cœurs fœtaux RCIU ainsi que sa régulation. Ensuite, nous avons approfondi les conséquences d’un métabolisme lipidique élevé dans les cœurs fœtaux RCIU. Le sexe des animaux a été pris en compte dans nos travaux. L’ensemble de ces travaux démontrent une plus grande utilisation du métabolisme lipidique chez les fœtus RCIU, impliquant une activation du récepteur nucléaire PPARα et du coactivateur PGC1a par une abondance d’acides gras (AG) à longue chaîne dans les cœurs fœtaux RCIU. L’activation de PPARα entraine une augmentation de l’expression de nombreux gènes impliqués dans l’oxydation des AG et de la biogenèse mitochondriale. Les mitochondries des cœurs fœtaux RCIU femelles montrent de plus grandes capacités de production d’ATP, comparées aux femelles témoins, mais aucune différence n’a été montrée chez les mâles. Un tel dysmorphisme a également été observé dans l’augmentation des capacités d’oxydation des AG à très longues chaînes chez les femelles RCIU, mais pas chez les mâles. L’augmentation de l’expression de Pdk4 dans les cœurs fœtaux RCIU confirme le fort métabolisme lipidique et suggère une abondance d’acétyl-CoA, molécule intermédiaire à plusieurs voies métaboliques, dont la production de corps cétoniques. Nous avons montré une synthèse intracardiaque de corps cétoniques chez les fœtus RCIU, sans élévation de la cétolyse, causant une accumulation d’acétoacétate et de β-hydroxybutyrate (bHB). Enfin, l’exploration des rôles signalétiques du bHB nous a permis d’observer une régulation positive de ce corps cétonique sur le métabolisme lipidique, par une activation de PPARα. En conclusion, ce projet de thèse a contribué à mieux comprendre les mécanismes d’adaptation métabolique des cœurs fœtaux à une RCIU causée par une diminution de la perfusion placentaire en fonction du sexe. Notre travail ouvre également la voie à de nouvelles avenues de recherche sur le rôle signalétique des corps cétoniques et des AG à longue chaîne dans la programmation des maladies cardiométaboliques. / An unfavorable womb environment often leads to intrauterine growth restriction (IUGR), which is known to increase the likelihood of developing cardiometabolic diseases later in life. The fetal environment is thus added to other factors such as heredity, sex and lifestyle that have an impact on cardiometabolic health. To investigate IUGR predisposed condition, our laboratory has developed an animal model of asymmetric IUGR by decreasing placental perfusion. Our findings using this animal model have highlighted sex-dependent differences in the cardiovascular physiology of IUGR adults, and specific changes in the expression of key genes involved in lipid metabolism in IUGR fetuses. Therefore, we hypothesize that the IUGR fetal heart undergoes a metabolic remodeling in response to the stress caused by the unfavorable uterine environment. We also expect selective metabolic changes in males and females. To verify this hypothesis, we addressed the contribution and regulation of lipid metabolism in IUGR fetal hearts. We also thoroughly investigated the consequences of a high lipid metabolism in IUGR fetal hearts. Changes between males and females were also considered. This study shows an increased use of lipid metabolism in IUGR fetuses, which involves the transcriptional activation of the nuclear receptor PPARα and the coactivator PGC1 in response to accumulated levels of specific long-chain fatty acids (FA) in IUGR fetal hearts. Activation of PPARα lead to an increase in the expression of critical genes involved in the oxidation of FAs and mitochondrial biogenesis. Mitochondrial respiration analysis demonstrated a greater ATP production capability in female IUGR fetal hearts compared to control females, a finding not observed in males. The increased expression of Pdk4 in IUGR fetal hearts attests such a strong lipid metabolism and suggests an abundance of acetyl-CoA, an intermediate molecule to several metabolic pathways, including the production of ketone bodies. Indeed, our results indicate an increased intracardiac synthesis of ketone bodies in IUGR fetuses without inducing ketolytic genes, resulting in significant accumulation of acetoacetate and β-hydroxybutyrate (bHB). Moreover, we provide evidence of a signaling role of bHB with a positive regulation of lipid metabolism through the transcriptional activation of PPARα. In conclusion, this thesis contributes to a better understanding of the mechanisms involved in the metabolic adaptation of fetal hearts to IUGR and highlights selective changes according to sex. Our study also paves the way for new research avenues on the signaling role of ketone bodies and long-chain FAs on the programming of cardiometabolic diseases.

The aim of this study was to investigate gene expression of cardiovascular miRNAs in peripheral blood of mothers after delivery. MiRNAs are small non-coding RNAs, which significantly modulate posttranscriptional adjustments of mRNA and thus regulate gene expression across biological processess. Dysregulation of miRNAs is associated with many pathological phenomena, thanks that we can use them for diagnosis and potentionaly we can treat these diseases by the manipulation of miRNA gene expression. We examined gene expression of circulating miRNAs associated with cardiovascular diseases, and we investigated, how the expression profile depends on pregnancy course and manifestation of pregnancy-related complications. For this purpose we examined material from 221 mothers 3-10 years after delivery. A group with identical pregnancy-related complication was always compared with a group of mothers after physiological pregnancy. Gene expression of 29 cardiovascular miRNAs in peripheral blood was studied using reverse transcription and quantitative real-time PCR. It was confirmed, that the expression profile of miRNAs differed between pregnancy-related complications and physiological controls. We also confirmed, that the profile of gene expression discovered at mothers 3-10 years after delivery was different...

Contexte : Près de 2,5 millions de nouveau-nés meurent chaque année et plus de 80 % d'entre eux ont un petit poids à la naissance (PPN). Le PPN est une entité clinique complexe impliquant le retard de croissance in utero (RCIU) et la naissance prématurée (NPM). Les nouveau-nés survivants sont exposés à un risque élevé de morbidités périnatales graves (telles que la dysplasie broncho-pulmonaire, l'entérocolite nécrosante, l'encéphalopathie néonatale) en raison des effets dévastateurs de l'inflammation utéro-fœtale sur les organes fœtaux vulnérables. Il n'existe actuellement aucun traitement efficace pour la protection fœtale ante partum. Parmi les nombreux médiateurs pro-inflammatoires, l'IL-1β se distingue par ses effets délétères. Notre laboratoire a conçu un nouvel antagoniste allostérique du récepteur de l'IL-1, Rytvela, qui s'est avéré efficace contre la NPM lorsqu'il est administré en prophylaxie. Objectif : Cette étude vise à mieux caractériser Rytvela en évaluant son efficacité dans la prévention de la NPM et du RCIU lorsqu'il est administré après l'insulte inflammatoire initiale selon un cadre clinique plus réaliste. Méthodes : Des souris gravides CD-1 ont reçu une injection d'agents pro-inflammatoires/pro-travail, soit l’IL-1β (1 μg i.u.) ou le LPS (10 μg i.p.) aux jours 16-17 de la gestation. Rytvela (2 mg/kg/jour s.c.) a été administré à différents intervalles de temps (0,5h, 2h, 4h, 6h) après l’induction inflammatoire. Le taux de NPM, la survie et le poids des souriceaux ont été évalués. Des analyses histologiques des poumons, intestins et cerveau des nouveau-nés ont été réalisées. Résultats : Toutes les grossesses traitées avec Rytvela ont été menées à terme dans le modèle de l’IL-1β, alors que le taux de NPM était de 57 % dans le groupe non traité. La survie, la croissance et le poids des souriceaux ont été considérablement améliorés avec Rytvela administré 0,5 h post-inflammation (avec une survie presque doublée des portées). L'analyse histologique a révélé dans tous les modèles une morphogenèse fœtale protégée, y compris une alvéolarisation pulmonaire préservée, des villosités intestinales intactes et un arbre cérébrovasculaire protégé associé à une masse cérébrale préservée. Conclusion : Rytvela est efficace dans la prévention de la NPM et du RCIU lorsqu'il est administré en post-inflammatoire. Il présente un effet maximal lorsqu'il était administré rapidement (0,5 h après IL-1β/LPS) et maintenait des effets protecteurs fœtaux significatifs avec une administration retardée (jusqu'à 6 h après IL-1β/LPS). Rytvela améliore la survie et la santé néonatale en préservant l'intégrité et la croissance des tissus fœtaux. Par conséquent, Rytvela est un nouveau prototype thérapeutique prometteur et sécuritaire pour le traitement de la NPM et du RCIU. / Background: Over 2.5 million newborns die yearly and more than 80% of them are of low birthweight (LBW). LBW is a complex clinical entity involving fetal growth restriction (FGR) and preterm birth (PTB). Surviving neonates face a higher risk of serious perinatal morbidities (such as bronchopulmonary dysplasia, necrotizing enterocolitis, neonatal encephalopathy) due to the devastating effects of utero-fetal inflammation on vulnerable fetal organs. There is currently no efficient treatment for fetal antepartum protection. Among the many proinflammatory mediators, IL-1β stands out for its detrimental effects. The host lab has designed a novel allosteric IL-1 receptor antagonist, Rytvela, which has been shown to be effective against PTB when administered prophylactically. Objective: This study aims to further characterize Rytvela by evaluating its efficacy in preventing PTB and FGR when administered after the initial inflammatory insult according to a more realistic clinical setting. Methods: Pregnant CD-1 mice were injected with proinflammatory/prolabour agents, either IL-1β (1 μg i.u.) or LPS (10 μg i.p.) on days 16-17 of gestation. Rytvela (2 mg/kg/day s.c.) was administered at different time intervals (0.5, 2, 4, 6 h) after initial inflammatory insults. PTB rate, neonatal survival, and weight were assessed. Histological analyses of the lungs, intestines, and brain of the neonates were performed. Results: All pregnancies treated with Rytvela were carried to term in the IL-1β model, while the PTB rate was 57% in the untreated group. Pup survival, growth and weight were considerably improved with Rytvela administered 0.5h post-inflammatory insults (with a nearly 2-fold increase in litters survival). Histological analysis revealed in all models a protected morphogenesis of vulnerable fetal organs including preserved lung alveolarization, intact intestinal villi integrity, and protected cerebrovascular tree associated with preserved brain mass. Conclusion: Rytvela is efficient in preventing PTB and FGR when administered post-inflammatory insults. It exhibited maximum effect when administered promptly (0.5h post-IL-1β/LPS) and maintained significant fetal protective effects with delayed administration (up to 6h post- IL-1β/LPS). Rytvela improved birth outcome by preserving fetal tissue integrity and growth. Hence, Rytvela is a promising new and safe therapeutic prototype for treatment of PTB and FGR.

As gestações gemelares monocoriônicas e diamnióticas (MCDA) apresentam maior risco de restrição de crescimento fetal (RCF) e complicações perinatais. O objetivo deste estudo foi avaliar a morbidade e mortalidade perinatal em gestações gemelares MCDA: na presença de RCF e dopplervelocimetria de artéria umbilical normal e anormal; nos diferentes padrões de dopplervelocimetria de artéria umbilical (doppler normal, índice de pulsatilidade aumentado, fluxo diastólico intermitente de artéria umbilical, diástole zero e diástole reversa) e na presença de RCF seletiva e não seletiva. Estudo retrospectivo, com levantamento dos casos no período entre 2004 e 2011, no Setor de Gestações Múltiplas da Clínica Obstétrica do HCFMUSP. Desta forma, foram inseridas 48 gestações gemelares, com 60 fetos abaixo do percentil 10 de uma curva específica para gêmeos. Casos que apresentaram malformações fetais (n=36) ou síndrome da transfusão fetofetal (n=43) não foram incluídos no estudo. O grupo com RCF e dopplervelocimetria anormal apresentou menor média de idade gestacional no parto (33,39 versus 35,48, p <0,001), menor média de peso ao nascimento (1137,12 gramas versus 1675,77 gramas, p < 0,001), maior frequência de internação em Unidade de terapia intensiva (UTI) neonatal (69,23% versus 19,23%, p = 0,0003), maior frequência de doença respiratória (73,08 versus 34,62, p = 0,005) e maior frequência de óbito intrauterino e neonatal (p = 0,025). Na avaliação dos diferentes padrões de dopplervelocimetria da artéria umbilical (normal, índice de pulsatilidade aumentado, fluxo diastólico intermitente, diástole zero e diástole reversa), os grupos diferiram em relação à média da idade gestacional no parto (35,48; 34,22; 33,33; 33,15 e 32,45 semanas, p < 0,001), frequência de internação em UTI neonatal (19,23; 50,00; 50,00; 85,71 e 100,00%, p < 0,001) e desfecho com alta hospitalar (96,15; 100,00; 83,33; 71,43 e 25,00%, p < 0,001). O grupo com diástole reversa apresentou os piores resultados perinatais. Na avaliação da RCF seletiva, não foi observada diferença significativa em relação à idade gestacional no parto (33,4 versus 33,4, p = 0,953), mas houve maior necessidade de intubação orotraqueal (62,5% versus 32,3%, p = 0,001) e ventilação mecânica (75,0% versus 41,2%, p = 0,0006) em relação ao grupo de RCF não seletiva. No grupo RCF seletiva houve maior número de casos de dopplervelocimetria de artéria umbilical com índice de pulsatilidade aumentada, fluxo intermitente, diástole zero e reversa (p = 0,005). Como conclusão o estudo demonstrou maior morbidade e mortalidade perinatal no grupo com dopplervelocimetria anormal com diferença significativa em relação aos padrões distintos de dopplervelocimetria e piores resultados na presença de diástole reversa. O grupo de RCF seletiva apresentou maior frequência de anormalidades na dopplervelocimetria de artéria umbilical e morbidade neonatal em relação ao grupo com RCF não seletiva / Monochorionic diamniotic (MCDA) twin pregnancies have and increased risk for intrauterine growth restriction (IUGR) and perinatal complications. The aim of this study is to evaluate perinatal morbidity and mortality in MCDA twin pregnancies: in the presence of IUGR with normal and abnormal umbilical artery dopplervelocimetry; in different umbilical artery flow patterns (normal dopplervelocimetry, increased pulsatility index, intermittent flow pattern, absent end diastolic flow and reversed end diastolic flow) and in the presence of selective and non-selective IUGR. This was a retrospective study in the Multiple Pregnancy Unit at the Obstetric Clinic of HCFMUSP, between 2004 and 2011. The study included 48 twin pregnancies, where 60 fetuses weighted less than the 10th percentile according to twins charts. Cases with fetal malformation (n=36) or twin to twin transfusion syndrome (n=43) were not included in the study. The group with IUGR and abnormal umbilical artery Doppler presented lower mean gestational age at delivery (33.39 versus 35.48, p <0.001), lower mean birthweight (1137.12 g versus 1675.77 g, p < 0.001), higher need of neonatal intensive care unit (NICU, 69.23% versus 19.23%, p = 0.0003), higher frequency of respiratory disease (73.08 versus 34.62, p = 0.005) and higher incidence of intrauterine and neonatal death (p = 0.025). In the different umbilical artery flow patterns (normal dopplervelocimetry, increased pulsatility index, intermittent flow pattern, absent end diastolic flow and reversed end diastolic flow) the group differ in relation to gestational age at delivery (35.48; 34.22; 33.33; 33.15 and 32.45 weeks; p < 0.001), need of NICU (19.23; 50.00; 50.00; 85.71 and 100,00%; p < 0.001) and alive at hospital discharge (96.15; 100,00; 83.33; 71.43 and 25,00%; p < 0.001). The group with reversed and diastolic flow presented the worse perinatal outcome. In the selective and non-selective IUGR groups, no difference was observed in relation to gestational age at delivery (33.4 versus 33.4 weeks, p = 0.953), however there was higher need for orotracheal intubation (62.5% versus 32.3%, p = 0.001) and mechanical ventilation (75.0% versus 41.2%, p = 0.0006) in the selective IUGR group. Abnormal umbilical artery Doppler such as increased pulsatility index, intermittent blood flow, absent and reversed flow were more frequent in the selective IUGR group (p = 0.005). As conclusion, the study demonstrated higher perinatal morbidity and mortality in the IUGR group with abnormal umbilical artery Doppler with significant difference in relation to Doppler patterns and the worse outcome was related to reversed diastolic flow pattern. The selective IUGR group presents higher frequency of abnormal umbilical artery dopplervelocimetry and neonatal morbidity compared to non- selective IUGR group

Uterine NK (uNK) cells are a distinct subset of NK cells in the decidua of humans and rodents during pregnancy, which are essential for remodelling of the spiral arteries supplying the feto-placental unit. Similarly to peripheral NK cells, uNK cells express Natural Killer receptors (NKRs) that engage MHC class I molecules. Evidence from human genetic association studies suggests that, in the presence of allogeneic cognate paternal MHC class I ligands, inhibitory uterine NKRs are associated with disorders of pregnancy arising from impaired decidual vascular remodelling. Conversely, enhancement of human uNK cell activity through activating NKRs is associated with high birth weight. Evidence from mouse models corroborates that uNK cell activity is modulated by interactions between NKRs and MHC class I, but has largely focussed on the effect of paternal MHC. In this study, the contribution of maternal immunogenetic regulation of NK cell function to reproductive outcome was assessed independently of parental MHC disparity in mice. To evaluate the role of NKR genes in isolation, I used congenic B6.BALB-TC1 (TC1) mice that differ from C57BL/6 (B6) mice only within the region of chromosome six encoding NKRs that recognise MHC class I. Absence of a major inhibitory NKR for self-MHC, Ly49I, in TC1 mice causes a compensatory shift in the NKR repertoire expressed and preserves a majority subpopulation of educated NK cells. B6 and TC1 splenic and uterine NK cells are similarly functionally reactive and mature, and no significant differences could be detected in spiral arterial remodelling or fetal growth between these strains in MHC-syngeneic matings. This supports data from human immunogenetic studies showing that maternal uterine NKRs are not associated with differences in pregnancy outcome in the absence of novel paternal MHC class I ligands, and highlights the importance of maternal and paternal co-regulation of uNK cell activity during pregnancy. No mouse models of uNK cell activation are currently available with which to corroborate human immunogenetic associations between activating uterine NKRs and high birth weight. Male m157-transgenic (m157-Tg) mice, which ubiquitously express viral m157 glycoprotein ligands for the activating NKR Ly49H, were mated with B6 females. Exclusive expression of m157 glycoprotein by trophoblast improved placental efficiency, but did not enhance fetal growth. Some fertility clinics surmise that uNK cell activation initiates the pathogenesis of spontaneous abortion. It has been suggested that this may occur due to reduced expression by human uNK cells of miR-483-3p, which stimulates endogenous insulin-like growth factor (IGF)-1 production and uNK cell cytotoxicity in vitro. It is demonstrated here that neither miR-483-3p nor IGF-1 regulate murine NK cell development, maturation or function. No discernible reproductive phenotype is evident in miR-483 deficient females. It can be inferred that post-transcriptional control by miR-483 is not biologically relevant to murine NK cell function. Although m157-Tg mice may provide an interesting model to further study uNK cell-mediated placental adaptations, it remains important to identify a murine model of enhanced uNK cell function to corroborate human immunogenetic associations with high birth weight and to challenge the supposition that uNK cell activation is harmful to pregnancy.

As gestações gemelares monocoriônicas e diamnióticas (MCDA) apresentam maior risco de restrição de crescimento fetal (RCF) e complicações perinatais. O objetivo deste estudo foi avaliar a morbidade e mortalidade perinatal em gestações gemelares MCDA: na presença de RCF e dopplervelocimetria de artéria umbilical normal e anormal; nos diferentes padrões de dopplervelocimetria de artéria umbilical (doppler normal, índice de pulsatilidade aumentado, fluxo diastólico intermitente de artéria umbilical, diástole zero e diástole reversa) e na presença de RCF seletiva e não seletiva. Estudo retrospectivo, com levantamento dos casos no período entre 2004 e 2011, no Setor de Gestações Múltiplas da Clínica Obstétrica do HCFMUSP. Desta forma, foram inseridas 48 gestações gemelares, com 60 fetos abaixo do percentil 10 de uma curva específica para gêmeos. Casos que apresentaram malformações fetais (n=36) ou síndrome da transfusão fetofetal (n=43) não foram incluídos no estudo. O grupo com RCF e dopplervelocimetria anormal apresentou menor média de idade gestacional no parto (33,39 versus 35,48, p <0,001), menor média de peso ao nascimento (1137,12 gramas versus 1675,77 gramas, p < 0,001), maior frequência de internação em Unidade de terapia intensiva (UTI) neonatal (69,23% versus 19,23%, p = 0,0003), maior frequência de doença respiratória (73,08 versus 34,62, p = 0,005) e maior frequência de óbito intrauterino e neonatal (p = 0,025). Na avaliação dos diferentes padrões de dopplervelocimetria da artéria umbilical (normal, índice de pulsatilidade aumentado, fluxo diastólico intermitente, diástole zero e diástole reversa), os grupos diferiram em relação à média da idade gestacional no parto (35,48; 34,22; 33,33; 33,15 e 32,45 semanas, p < 0,001), frequência de internação em UTI neonatal (19,23; 50,00; 50,00; 85,71 e 100,00%, p < 0,001) e desfecho com alta hospitalar (96,15; 100,00; 83,33; 71,43 e 25,00%, p < 0,001). O grupo com diástole reversa apresentou os piores resultados perinatais. Na avaliação da RCF seletiva, não foi observada diferença significativa em relação à idade gestacional no parto (33,4 versus 33,4, p = 0,953), mas houve maior necessidade de intubação orotraqueal (62,5% versus 32,3%, p = 0,001) e ventilação mecânica (75,0% versus 41,2%, p = 0,0006) em relação ao grupo de RCF não seletiva. No grupo RCF seletiva houve maior número de casos de dopplervelocimetria de artéria umbilical com índice de pulsatilidade aumentada, fluxo intermitente, diástole zero e reversa (p = 0,005). Como conclusão o estudo demonstrou maior morbidade e mortalidade perinatal no grupo com dopplervelocimetria anormal com diferença significativa em relação aos padrões distintos de dopplervelocimetria e piores resultados na presença de diástole reversa. O grupo de RCF seletiva apresentou maior frequência de anormalidades na dopplervelocimetria de artéria umbilical e morbidade neonatal em relação ao grupo com RCF não seletiva / Monochorionic diamniotic (MCDA) twin pregnancies have and increased risk for intrauterine growth restriction (IUGR) and perinatal complications. The aim of this study is to evaluate perinatal morbidity and mortality in MCDA twin pregnancies: in the presence of IUGR with normal and abnormal umbilical artery dopplervelocimetry; in different umbilical artery flow patterns (normal dopplervelocimetry, increased pulsatility index, intermittent flow pattern, absent end diastolic flow and reversed end diastolic flow) and in the presence of selective and non-selective IUGR. This was a retrospective study in the Multiple Pregnancy Unit at the Obstetric Clinic of HCFMUSP, between 2004 and 2011. The study included 48 twin pregnancies, where 60 fetuses weighted less than the 10th percentile according to twins charts. Cases with fetal malformation (n=36) or twin to twin transfusion syndrome (n=43) were not included in the study. The group with IUGR and abnormal umbilical artery Doppler presented lower mean gestational age at delivery (33.39 versus 35.48, p <0.001), lower mean birthweight (1137.12 g versus 1675.77 g, p < 0.001), higher need of neonatal intensive care unit (NICU, 69.23% versus 19.23%, p = 0.0003), higher frequency of respiratory disease (73.08 versus 34.62, p = 0.005) and higher incidence of intrauterine and neonatal death (p = 0.025). In the different umbilical artery flow patterns (normal dopplervelocimetry, increased pulsatility index, intermittent flow pattern, absent end diastolic flow and reversed end diastolic flow) the group differ in relation to gestational age at delivery (35.48; 34.22; 33.33; 33.15 and 32.45 weeks; p < 0.001), need of NICU (19.23; 50.00; 50.00; 85.71 and 100,00%; p < 0.001) and alive at hospital discharge (96.15; 100,00; 83.33; 71.43 and 25,00%; p < 0.001). The group with reversed and diastolic flow presented the worse perinatal outcome. In the selective and non-selective IUGR groups, no difference was observed in relation to gestational age at delivery (33.4 versus 33.4 weeks, p = 0.953), however there was higher need for orotracheal intubation (62.5% versus 32.3%, p = 0.001) and mechanical ventilation (75.0% versus 41.2%, p = 0.0006) in the selective IUGR group. Abnormal umbilical artery Doppler such as increased pulsatility index, intermittent blood flow, absent and reversed flow were more frequent in the selective IUGR group (p = 0.005). As conclusion, the study demonstrated higher perinatal morbidity and mortality in the IUGR group with abnormal umbilical artery Doppler with significant difference in relation to Doppler patterns and the worse outcome was related to reversed diastolic flow pattern. The selective IUGR group presents higher frequency of abnormal umbilical artery dopplervelocimetry and neonatal morbidity compared to non- selective IUGR group

Le retard de croissance intra-utérin (RCIU) est une complication fréquente de la grossesse qui se traduit à la naissance par un poids et/ou une taille inférieurs au dixième percentile par rapport à l’âge gestationnel. Il représente un problème majeur de santé publique avec une augmentation de la morbi-mortalité néonatale et un risque accru de développer des maladies cardiovasculaires et un diabète à l’âge adulte. Le RCIU humain est une pathologie complexe et multifactorielle avec une physiopathologie incomplètement élucidée dans près de 30 à 40% des cas. L’objectif de ce travail a été de progresser sur la physiopathologie du RCIU humain et de proposer des gènes candidats impliqués. J’ai analysé les perturbations d’expression génique dans des placentas issus de grossesses avec et sans RCIU, participé à la caractérisation d’un modèle animal de rate gestante soumise à un régime hypoprotidique, mis au point et validé un modèle cellulaire de cellules JEG-3 transformées par surexpression du gène PDX1 et/ou déplétées en acides aminés constituant un modèle important des effets du RCIU. J’ai étudié le rôle et l’implication de plusieurs gènes candidats : IMP3, les Cullines et PDX1. J’ai enfin participé à l’identification de nouveaux gènes soumis à empreinte dans le placenta. Ce travail de thèse a confirmé le rôle essentiel de l’apoptose et des régulations épigénétiques, plus particulièrement les modifications de profil de méthylation de l’ADN, dans le RCIU. L’analyse transcriptomique des placentas humains de grossesse avec RCIU a confirmé le rôle essentiel de 3 gènes : la leptine, IGFBP1 et RBP4. Enfin l’utilisation de notre modèle cellulaire a permis de confirmer l’implication de PDX1 dans le RCIU, PDX1 contrebalance les effets transcriptomiques de la déplétion en acides aminés sur les cellules JEG en culture. En extrapolant ces résultats à la pathologie humaine, on peut émettre l’hypothèse que l’induction placentaire de PDX1 en situation de RCIU permettrait de contrebalancer ou de limiter les effets délétères du RCIU pour la survie du fœtus. La leptine, IGFBP, RBP4 et PDX1 sont de bons candidats à la fois pour l’origine du RCIU et également pour la prédiction de l’évolution possible vers un syndrome métabolique chez les adultes anciens RCIU. Des études complémentaires sur le rôle et l’implication de ces 4 gènes dans la physiopathologie du RCIU ainsi que dans la programmation fœtale des pathologies cardiovasculaires, de l’obésité et de l’intolérance glucidique à l’âge adulte restent nécessaires. / Intra-uterine growth restriction (IUGR) is a frequent complication of pregnancy that leads to a baby with a birth weight and/or size below the 10th percentile for a given gestational age. IUGR represents a major public health problem associated with neonatal increased morbidity and mortality and an increased risk to develop cardiovascular pathologies and diabetes in adulthood. Human IUGR is a complex and multi-factorial pathology with an incompletely characterised physiopathology in up to 30 to 40% of cases. The goal of this work was to improve the knowledge on the physiopathology of IUGR and to propose implicated candidate genes.I analysed modulations of gene expression in placentas from pregnancies with and without IUGR, participated to the characterisation of an IUGR animal model of female rat fed with a hypoprotidic diet during gestation, set up and validated a cellular model of JEG-3 cells transformed by over-expression of the PDX1 gene and/or depletion of amino acids to provide a handy model of IUGR effects. I studied the role and implication of candidate genes: IMP3, the Cullin family and PDX1. Finally I participated to the identification of new imprinted genes in the human placenta. This thesis work confirmed the essential role of apoptosis and epigenetic regulations, in particular modifications of DNA methylation profiles, in IUGR. Transcriptomic analysis of human placentas from IUGR and control pregnancies confirmed the crucial role of 3 genes: leptin, IGFBP1 and RBP4. Finally, the use of our cellular model strengthened the role of PDX1 in IUGR, where it counterbalances the transcriptomic effects of amino acid depletion in cultured JEG-3 cells. By extrapolating these results to the human pathology, we can suggest the hypothesis that the placental induction of PDX1 in IUGR could counterbalance or limit the deleterious effects of IUGR on the foetus’ survival. Leptin, IGFBP1, RBP4 and PDX1 are good candidates to explain the origin of IUGR as well as to predict the potential evolution towards a metabolic syndrome in adults that suffered from IUGR. Complementary studies on the role and function of these 4 genes in IUGR physiopathology and also in foetal programming of cardiovascular pathologies, obesity and glucidic intolerance in adulthood remain necessary.

L’insuffisance placentaire par défaut de vascularisation est une pathologie fréquente de la grossesse, de diagnostic difficile, avec des complications potentiellement graves (retard de croissance intra utérin, prééclampsie). L’objectif de ce travail de Thèse a été de développer l’IRM fonctionnelle multiparamétrique pour l’exploration du placenta à 4.7 T chez la rate gestante. Matériel et méthode : L’IRM de diffusion (SE- EPI DWI) avec analyse IVIM et l’IRM dynamique avec injection de gadolinium (DCE) et haute résolution temporelle (< 1s) ont été développées puis étudiées sur un modèle murin contrôlé d’hypoperfusion placentaire par ligature du pédicule vasculaire utérin gauche au 17ème jour de gestation. Les paramètres obtenus sur les placentas hypoperfusés de la corne gauche ligaturée étaient comparés à ceux des placentas normaux de la corne droite. L’effet de l’hyperoxygénation maternelle était étudié en diffusion. Résultats : Ont été étudiés 73 placentas, dont 23 pathologiques (n= 10 rates) en diffusion et 53 placentas, dont 11 pathologiques (n=12 rates) en DCE. Les paramètres significativement diminués du côté hypoperfusé étaient le coefficient apparent de diffusion (ADC), la fraction de perfusion (f) en diffusion et le flux sanguin maternel (F) en DCE. Sous hyperoxygénation maternelle, l’ADC et le coefficient de diffusion (D) augmentaient et f diminuait. Les paramètres obtenus en diffusion et en DCE n’étaient pas nettement corrélés entre eux. Conclusion : Un outil d’IRM fonctionnelle placentaire multiparamétrique a été développé à 4.7 T chez la rate gestante. La DWI comme la DCE apparaissent complémentaires pour le diagnostic d’hypoperfusion placentaire. / Placental insufficiency caused by deficient vascularization is common during pregnancy, difficult to diagnose and can lead to severe materno-fetal complications (intrauterine growth restriction, preeclampsia). The aim of this work was to develop multi-parametric functional magnetic resonance imaging (MRI) to assess the placenta at 4.7 T on a murine model. Materials and methods : Diffusion-weighted imaging (SE-EPI-DWI) with the intravoxel incoherent motion (IVIM) analysis and dynamic contrast enhanced MRI (DCE) with a high-time resolution (<1 s) were developed and evaluated on a controlled rat model of reduced placental perfusion, achieved by ligation of the left uterine vascular pedicle on the 17th embryonic day. Parameters from the placentas in the left ligated horn were compared to those from the normal placentas in the non ligated horn. The effect of maternal hyperoxygenation on placental microvascularization was studied with DWI.Results: For DWI, 73 placentas were examined, 23 from the ligated side (n=10 rats). For DCE, 53 placentas were analysed, 11 from the ligated side (n=12 rats). In the uterine horn with reduced perfusion, the apparent diffusion coefficient (ADC), the perfusion fraction (f) obtained with DWI and the placental blood flow (F) obtained with DCE were significantly decreased. Under maternal hyperoxygenation, ADC and the diffusion coefficient (D) increased whereas f decreased. DWI and DCE parameters were not significantly correlated with each other. Conclusion: Multi-parametric MRI has been developed for murine placental analysis at 4.7T. DWI and DCE are complementary tools for the diagnosis of reduced placental perfusion.

Die Entwicklung eines Embryos und Fetus beeinflusst die Anfälligkeit für kardiovaskuläre Erkrankungen im weiteren Verlauf des Lebens entscheidend. Zugrundeliegende Mechanismen sind jedoch weitestgehend unbekannt. Unter Zuhilfenahme eines neuen Mausmodells für intrauterine kardiale Wachstumsretardierung zielt die vorliegende Dissertation auf die Identifikation adaptiver Wachstumsmechanismen ab, welche die Anpassung der Organgröße und die Aufrechterhaltung einer normalen Herzfunktion ermöglichen. Vielzählige Gene des Aminosäure (AS)-Metabolismus und der Proteinhomeostase zeigten eine vermehrte Expression in neugeborenen Mausherzen nach gestörter Embryonalentwicklung. Es wurde angenommen, dass sowohl die AS-Verfügbarkeit als auch die Aktivität der mechanistic target of rapamycin (mTOR) Signalkaskade entscheidend für eine normale Herzentwicklung und postnatales kompensatorisches Wachstum sind. Der mTOR Komplex 1 (mTORC1) wurde in prä- und perinatalen Mäusen mittels Rapamycin-Behandlung trächtiger Weibchen inhibiert. Die Auswirkungen einer prä- und postnatalen AS-Restriktion wurden anhand einer Niedrigproteindiät untersucht. Rapamycin-behandelte Neugeborene zeichneten sich durch vermindertes Gesamtwachstum sowie Entwicklungsverzögerung aus. Dabei war die kardiale Entwicklung besonders betroffen. Kardiale Proliferationsraten waren nicht verändert, die verminderte Herzgröße wurde jedoch auf eine verringerte Kardiomyozytengröße sowie eine erhöhte Apoptoserate zurückgeführt. Die intrauterine AS-Restriktion wurde überraschend gut von den Mausherzen toleriert. Zusammenfassend konnte gezeigt werden, dass die mTOR Signalkaskade essentiell für eine normale Herzentwicklung sowie kompensatorisches kardiales Wachstum ist. Darüber hinaus stellt die pränatale Rapamycin-Behandlung möglicherweise ein neues Modell der intrauterinen Wachstumsretardierung dar, welches Untersuchungen von Programmierungs-Mechanismen vor allem während der fötalen und perinatalen Herzentwicklung ermöglicht. / Intrauterine development influences the susceptibility to cardiovascular disease in adulthood, although the underlying molecular mechanisms are vastly unknown. Utilizing a new mouse model of impaired heart development, this thesis aims at identifying pre- and postnatal adaptive growth mechanisms to restore organ size and allow normal cardiac function. Unbiased functional annotation of genes differentially expressed in neonatal hearts after impaired intrauterine development revealed numerous gene clusters involved in amino acid (AA) metabolism and protein homeostasis. It was hypothesized that both AA availability and mechanistic target of rapamycin (mTOR) pathway activation are crucial for normal heart development and compensatory cardiac growth. mTOR complex 1 (mTORC1) was inhibited in fetal and neonatal mice by rapamycin treatment of pregnant dams. The effects of pre- and postnatal AA restriction were studied by feeding dams a low protein diet (LPD) throughout pregnancy and keeping the offspring on LPD postnatally. Rapamycin treated neonates were characterized by overall growth restriction and developmental delay, where cardiac development was especially affected (reduction of heart size, weight and heart weight to body weight ratio, severe thinning and noncompaction of the ventricular myocardium as well as immature myocardial morphology). While proliferation rates were unaffected, the reduced neonatal heart size was attributed to decreased cardiomyocyte size and increased apoptosis. Strikingly, the murine heart appeared to be surprisingly resistant to intrauterine AA restriction. In conclusion, the data revealed mTOR being essential for normal as well as compensatory cardiac development and growth. Moreover, prenatal rapamycin treatment might represent a new model of intrauterine growth restriction, which potentially allows the investigation of developmental programming mechanisms within the heart particularly in the fetal and neonatal phase of development.