Introduction: The placenta is essential for fetal development and pregnancy prolongation. Its dysfunction can lead to short and long-term health consequences for mother and child. A subset of diseases resulting from placental dysfunction have been collectively termed placental-mediated diseases (PMD) - which includes the common and serious hypertensive disorder of pregnancy preeclampsia (PE), among others. PMDs are independent risk factors for maternal cardiovascular disease (CVD) in later life. This thesis presents a multi-pronged body of work, which includes: 1) A systematic review, aimed at summarizing the current state of knowledge on the risk for future maternal CVD after PMDs; 2) A cohort study, aimed at assessing the utility of placenta pathology examination at delivery to identify women at high lifetime risk for CVD following PE; and 3) An assessment of an immunohistochemistry screening panel for 3 placenta protein markers of interest, aimed at determining if these markers can accurately identify women deemed to be at high-risk for future CVD following a PE pregnancy. Methods: 1) We searched 4 databases for observational studies evaluating clinical and biochemical markers of CVD risk and/or a subsequent calculated risk score based on these parameters in women with a history of PMD. We excluded interventional studies and studies measuring these outcomes during or prior to pregnancy. 2) A cohort study was established across two clinical sites (Kingston, Ottawa), in which patients with PE (N=85) underwent cardiovascular risk assessments at 6-months postpartum. The placentas from these pregnancies also underwent detailed placenta histopathology examination to determine the presence, absence, and severity of 35 distinct placental lesions. The associations between distinct placental lesions and estimated lifetime cardiovascular risk were evaluated by odds ratios (OR) and receiver operator curve analysis (ROC). 3) Immunohistochemistry (IHC) analysis was performed on placental samples from a subset of the previously described cohort (N=41; Ottawa site only). Protein expression for FLT-1, ENG, and CD68 was quantified. Using a multivariate logistic regression model, the association between placenta protein expression, with and without clinical and placenta pathology findings, and cardiovascular risk was assessed. Results: 1) The search yielded 11,039 articles of which 104 met our inclusion criteria. All PMD types demonstrated evidence of increased CVD risk markers at varying timepoints postpartum. At least one study per PMD type had non-optimal measures of systolic blood pressure, BMI, and total cholesterol. 2) In the analysis of placenta pathology lesions within the cohort of individuals with PE, lesions of maternal vascular malperfusion (MVM) were found to be associated with elevated life-time risk for maternal CVD at 6 months postpartum (OR: 3.10[1.20-7.92]). We also found that adding these lesions to a logistic regression model improved the predictive accuracy for elevated maternal lifetime CVD risk (AUC: 73.0, sensitivity: 78.4%, specificity: 51.6%). 3) Individually, no significant differences were found in FLT-1, ENG, and CD68 expression between the individuals deemed to be at high and low-risk for lifetime CVD. Although, when added to a model that included placenta pathology lesions and clinical data the predictive accuracy for elevated maternal lifetime CVD risk increased (AUC: 1.0, sensitivity: 100%, specificity: 100%). Conclusions: In conclusion, this thesis provides further evidence of the utility of assessing placenta features in the prediction of future maternal CVD. This is evidenced by the association between PMDs, placental pathology, and placental protein biomarkers with elevated risk profiles for lifetime CVD. Thus, specific placental phenotypes of PMDs may be at increased risk for CVD. The use of placental data should be further explored as a triage strategy to identify these high-priority of women following delivery.

INTRODUÇÃO: A restrição de crescimento fetal (RCF) representa uma das principais complicações da gravidez e está associada a elevadas taxas de morbimortalidade perinatal. A frequência de desfechos desfavoráveis neonatais está diretamente relacionada à gravidade da RCF, sendo que os casos de pior evolução estão relacionados com peso abaixo do percentil 3. O mecanismo do crescimento fetal não está totalmente esclarecido, mas resulta da interação entre potencial genético de crescimento e fatores placentários, maternos e ambientais. Dentre os fatores etiológicos, o desenvolvimento anormal da placenta e a diminuição da perfusão uteroplacentária são as principais causas de RCF. Este estudo teve por objetivo avaliar volume e índices de vascularização placentários, por meio da ultrassonografia tridimensional (US3D), em gestações com RCF grave, e as correlações dos parâmetros placentários com valores de normalidade e dopplervelocimetria materno-fetal. MÉTODOS: Foram avaliadas 27 gestantes cujos fetos apresentavam peso estimado abaixo do percentil 3 para a idade gestacional. Por meio da US3D, utilizando-se a técnica VOCAL, foram mensurados o volume placentário (VP) e os índices vasculares: índice de vascularização (IV), índice de fluxo (IF) e índice de vascularização e fluxo (IVF). Os dados foram comparados com a curva de normalidade para a idade gestacional e peso fetal descrita por De Paula e cols. (2008, 2009). Desde que os volumes placentários variam durante a gravidez, os valores observados foram comparados com os valores esperados para a idade gestacional e peso fetal. Foram criados os índices volume observado/ esperado para a idade gestacional (Vo/e IG) e volume placentário observado/ esperado para o peso fetal (Vo/e PF). Os parâmetros placentários foram correlacionados com índice de pulsatilidade (IP) médio de (AUt) e IP de artéria umbilical (AU), e avaliados segundo a presença de incisura protodiastólica bilateral em AUt. RESULTADOS: Quando comparadas à curva de normalidade, as placentas de gestação com RCF grave apresentaram VP, IV, IF e IVF significativamente menores (p < 0,0001 para todos os parâmetros). Houve correlação inversa estatisticamente significante da média do PI de AUt com o Vo/e IG (r= -0,461, p= 0,018), IV (r= -0,401, p= 0,042) e IVF (r= -0,421, p= 0,048). No grupo de gestantes que apresentavam incisura protodiastólica bilateral de artérias uterinas, Vo/e IG (p= 0,014), Vo/e PF (p= 0,02) e IV (p= 0,044) foram significativamente mais baixos. Nenhum dos parâmetros placentários apresentou correlação significativa com IP de AU. CONCLUSÕES: Observou-se que o volume e os índices de vascularização placentários apresentam-se diminuídos nos fetos com RCF grave. IP médio de AUT apresenta correlação negativa com Vo/e IG, IV e IVF, e Vo/e IG, Vo/e PF e IV apresentaram-se reduzidos nos casos de incisura bilateral. Não houve correlação significativa dos parâmetros placentários com IP de AU / INTRODUCTION: Fetal growth restriction (FGR) is a major complication of pregnancy and it is associated with high rates of perinatal morbidity and mortality. The frequency of neonatal adverse outcome is directly related to the severity of FGR and the cases of poor prognosis are related to weight below the 3rd percentile. Abnormal placental development and decreased uteroplacental perfusion is one of the main causes of FGR. This study aimed to evaluate placental volume and vascular indices by three-dimensional ultrasonography (3DUS) in pregnancies with severe FGR, and their correlation with normal values and maternal-fetal doppler. METHODS: We studied 27 pregnant women whose fetuses had estimated weight below the 3rd percentile for gestational age. Placental volume (PV) and placental indices- vascularity index (VI), flow index (FI) and vascularization and flow index (VFI)- were measured by the 3DUS using the VOCAL technique. These were compared to volume and vascularization normogram described by De Paula e cols. (2008, 2009). Since placental volumes vary throughout pregnancy, the observed values were compared to the expected values at the gestational age and to fetal weight. The observed-to-expected placental volume ratio for gestacional age (PVR-GA) and the observed-to-expected placental volume ratio for fetal weight (PVR-FW) were calculated. Placental parameters were correlated with uterine arteries (UtA) mean pulsatility index (PI) of umbilical artery(UA) PI and they were also evaluated according to the presence of bilateral protodiastolic notch in UtA. RESULTS: Compared to normal curve, the placentas of severe FGR pregnancies showed PV, VI, FI and VFI significantly lower (p < 0,0001 for all parameters). There was a statistically significant inverse correlation of UtA mean PI to PVR-GA (r= - 0,461, p= 0,018), VI(r= -0,401, p= 0,042) and VFI(r= -0,421, p= 0,048. In the group of women who had bilateral protodiastolic notch in UtA, PVR-GA (p= 0,014), PVR-FW (p= 0,02) and VI (p= 0,044) were significantly lower. None of placental parameters correlated significantly with UA PI. CONCLUSIONS: Volume and placental vascularization indices are decreased in fetuses with severe FGR. UtA mean PI has a negative correlation with PVR-GA, VI and VFI, and PVR-GA, PVR-FW and VI are decreased in cases with UtA bilateral notch. There was no correlation of placental parameters to UA PI

INTRODUÇÃO: A restrição de crescimento fetal (RCF) representa uma das principais complicações da gravidez e está associada a elevadas taxas de morbimortalidade perinatal. A frequência de desfechos desfavoráveis neonatais está diretamente relacionada à gravidade da RCF, sendo que os casos de pior evolução estão relacionados com peso abaixo do percentil 3. O mecanismo do crescimento fetal não está totalmente esclarecido, mas resulta da interação entre potencial genético de crescimento e fatores placentários, maternos e ambientais. Dentre os fatores etiológicos, o desenvolvimento anormal da placenta e a diminuição da perfusão uteroplacentária são as principais causas de RCF. Este estudo teve por objetivo avaliar volume e índices de vascularização placentários, por meio da ultrassonografia tridimensional (US3D), em gestações com RCF grave, e as correlações dos parâmetros placentários com valores de normalidade e dopplervelocimetria materno-fetal. MÉTODOS: Foram avaliadas 27 gestantes cujos fetos apresentavam peso estimado abaixo do percentil 3 para a idade gestacional. Por meio da US3D, utilizando-se a técnica VOCAL, foram mensurados o volume placentário (VP) e os índices vasculares: índice de vascularização (IV), índice de fluxo (IF) e índice de vascularização e fluxo (IVF). Os dados foram comparados com a curva de normalidade para a idade gestacional e peso fetal descrita por De Paula e cols. (2008, 2009). Desde que os volumes placentários variam durante a gravidez, os valores observados foram comparados com os valores esperados para a idade gestacional e peso fetal. Foram criados os índices volume observado/ esperado para a idade gestacional (Vo/e IG) e volume placentário observado/ esperado para o peso fetal (Vo/e PF). Os parâmetros placentários foram correlacionados com índice de pulsatilidade (IP) médio de (AUt) e IP de artéria umbilical (AU), e avaliados segundo a presença de incisura protodiastólica bilateral em AUt. RESULTADOS: Quando comparadas à curva de normalidade, as placentas de gestação com RCF grave apresentaram VP, IV, IF e IVF significativamente menores (p < 0,0001 para todos os parâmetros). Houve correlação inversa estatisticamente significante da média do PI de AUt com o Vo/e IG (r= -0,461, p= 0,018), IV (r= -0,401, p= 0,042) e IVF (r= -0,421, p= 0,048). No grupo de gestantes que apresentavam incisura protodiastólica bilateral de artérias uterinas, Vo/e IG (p= 0,014), Vo/e PF (p= 0,02) e IV (p= 0,044) foram significativamente mais baixos. Nenhum dos parâmetros placentários apresentou correlação significativa com IP de AU. CONCLUSÕES: Observou-se que o volume e os índices de vascularização placentários apresentam-se diminuídos nos fetos com RCF grave. IP médio de AUT apresenta correlação negativa com Vo/e IG, IV e IVF, e Vo/e IG, Vo/e PF e IV apresentaram-se reduzidos nos casos de incisura bilateral. Não houve correlação significativa dos parâmetros placentários com IP de AU / INTRODUCTION: Fetal growth restriction (FGR) is a major complication of pregnancy and it is associated with high rates of perinatal morbidity and mortality. The frequency of neonatal adverse outcome is directly related to the severity of FGR and the cases of poor prognosis are related to weight below the 3rd percentile. Abnormal placental development and decreased uteroplacental perfusion is one of the main causes of FGR. This study aimed to evaluate placental volume and vascular indices by three-dimensional ultrasonography (3DUS) in pregnancies with severe FGR, and their correlation with normal values and maternal-fetal doppler. METHODS: We studied 27 pregnant women whose fetuses had estimated weight below the 3rd percentile for gestational age. Placental volume (PV) and placental indices- vascularity index (VI), flow index (FI) and vascularization and flow index (VFI)- were measured by the 3DUS using the VOCAL technique. These were compared to volume and vascularization normogram described by De Paula e cols. (2008, 2009). Since placental volumes vary throughout pregnancy, the observed values were compared to the expected values at the gestational age and to fetal weight. The observed-to-expected placental volume ratio for gestacional age (PVR-GA) and the observed-to-expected placental volume ratio for fetal weight (PVR-FW) were calculated. Placental parameters were correlated with uterine arteries (UtA) mean pulsatility index (PI) of umbilical artery(UA) PI and they were also evaluated according to the presence of bilateral protodiastolic notch in UtA. RESULTS: Compared to normal curve, the placentas of severe FGR pregnancies showed PV, VI, FI and VFI significantly lower (p < 0,0001 for all parameters). There was a statistically significant inverse correlation of UtA mean PI to PVR-GA (r= - 0,461, p= 0,018), VI(r= -0,401, p= 0,042) and VFI(r= -0,421, p= 0,048. In the group of women who had bilateral protodiastolic notch in UtA, PVR-GA (p= 0,014), PVR-FW (p= 0,02) and VI (p= 0,044) were significantly lower. None of placental parameters correlated significantly with UA PI. CONCLUSIONS: Volume and placental vascularization indices are decreased in fetuses with severe FGR. UtA mean PI has a negative correlation with PVR-GA, VI and VFI, and PVR-GA, PVR-FW and VI are decreased in cases with UtA bilateral notch. There was no correlation of placental parameters to UA PI

Made available in DSpace on 2014-07-29T15:04:33Z (GMT). No. of bitstreams: 1 Dissertacao Raphaela Maioni Xavier.pdf: 942765 bytes, checksum: 101261116404b23fe8473b4c0bb5ae74 (MD5) Previous issue date: 2011-03-25 / The etiopathogenesis of gestational hypertension has been widely studied, but it is not very well established in medical literature. Due to the low uteroplacental perfusion, light to moderate hypertension in the third trimester of pregnancy may be an adaptive response of the maternal organism in order to keep adequate blood flow in the fetal compartment. This paper aims to identify the socioeconomic factors of the parturients with gestational hypertension associated with the maternal and fetal conditions, as well as the gross placental pathological changes. The study was conducted in a federal public maternity hospital in Goiânia, in the state of Goiás, between March 2009 and February 2010. Placental and clinical data of 61 parturients with and without diagnosis (control group) of gestational hypertension were collected. 18 placentas of parturients with chronic hypertension (CH) (29.5%), 11 with gestational hypertension (HGE) (18%), 3 with eclampsia (4.9%), 28 of pre-eclampsia (PE) (45.9%), and 1 diagnosed with HELLP Syndrome (1.63%). The main placental changes found were: hematomas, presence of fibrin, fibrosis, infarction, calcifilaxis and areas of detachment. There was statistically significant difference concerning the occurrence of infarction on the maternal side of women with eclampsia (p = 0.047). The deposit of fibrin on the maternal side of the placentas of women with gestational hypertension was significantly larger than that of the women in the control group (p = 0.008). Calcifilaxis was larger on the maternal side of the placentas of women in the control group when compared to the group with gestational hypertension (p = 0.056). A statistically significant result was obtained when analyzing the presence of fibrin in the groups of PE and control (p = 0.024). There was a significantly larger deposit of fibrin on the fetal side of the placentas of women with HGE than of those in the control group (p = 0.048). Hypertensive disorders of pregnancy are studied as a worldwide problem of public health and rank third among the causes of maternal death in the world and first in Brazil. This is the reason why this study was carried out taking into consideration the need of an increasingly humanized obstetric care focused on the main placental changes and their impact on maternal and fetal vitality in the puerperium. / A etiopatogênese da doença hipertensiva específica da gestação (DHEG) tem sido amplamente estudada, porém não se encontra muito bem estabelecida na literatura. Devido à baixa perfusão uteroplacentária, quadros hipertensivos leves a moderados no terceiro trimestre da gravidez podem ser uma resposta adaptativa do organismo materno para que seja mantido fluxo sanguíneo adequado no compartimento fetal. O objetivo deste estudo foi identificar os fatores sócio-econômicos das parturientes com doença hipertensiva da gestação associados às condições maternas e fetais, bem como as alterações anatomopatológicas macroscópicas placentárias. O estudo foi realizado em uma maternidade pública federal na cidade de Goiânia, Goiás, no período de março de 2009 a fevereiro de 2010. Foram coletados dados placentários e dados de prontuários de parturientes com ou sem diagnóstico (grupo controle) de doença hipertensiva específica da gestação totalizando 61 partos. Obtivemos 1 placenta de parturiente com diagnóstico de Síndrome HELLP (1,7%), 3 casos de eclâmpsia (4,9%), 11 de HG (18%),18 de HC (29,5%) e 28 de PE (45,9%). As principais alterações placentárias encontradas foram: hematomas, presença de fibrina, áreas de fibrose, infarto, calcifilaxia, áreas de descolamento. Na face materna houve diferença estatisticamente significante em relação à ocorrência de infarto na face materna de mulheres com eclâmpsia (p = 0, 047). Houve depósito de fibrina significativamente maior na face materna de placentas de mulheres com hipertensão gestacional comparada aquelas do grupo controle (p = 0,008). A calcificação foi maior na face materna das placentas de mulheres do grupo controle quando comparadas ao grupo com Hipertensão gestacional (p = 0,056). Obteve-se um resultado estatisticamente significante ao analisar a presença de fibrina nos grupos de PE e nos controles (p = 0,024). Houve um depósito significativamente maior de fibrina na face fetal das placentas de mulheres com HG comparadas aquelas do grupo controle (p = 0,048). As doenças hipertensivas específicas da gestação são estudadas como um problema de saúde pública mundial representando a terceira causa de mortalidade materna no mundo e a primeira no Brasil. Por esse motivo, o presente estudo foi realizado a partir da necessidade de uma assistência obstétrica cada vez mais humanizada e voltada para as principais alterações placentárias e suas repercussões na vitalidade materna e fetal no ciclo gravídico puerperal.

Des travaux antérieurs effectués dans notre laboratoire ont démontré une corrélation entre les niveaux circulants de peroxyde d'hydrogène (H[indice inférieur 2]O[indice inférieur 2]) et d'hormone gonadotrophine chorionique humaine (hCG) chez des femmes souffrant de prééclampsie (Kharfi et al, . 2005). Le peroxyde d'hydrogène étant surtout connu pour ses effets cytotoxiques, nous avons déterminé quels étaient ses effets sur des cellules placentaires in vitro, en rapport aux conditions retrouvées in vivo chez des femmes prééclamptiques. Pour ce faire, nous avons développé un modèle d'étude de cellules trophoblastiques in vitro, avec lequel nous avons pu évaluer les effets du peroxyde d'hydrogène sur la fonction placentaire via la production d'hCG, sur la production de TNF-[alpha] comme marqueur inflammatoire et sur l'oxyde nitrique (NO) comme facteur vasodilatateur. Nos résultats nous ont permis de constater divers effets du peroxyde d'hydrogène sur les cytotrophoblastes in vitro, effets qui peuvent être corrélés avec les niveaux constatés chez la femme prééclamptique. Premièrement, nous avons pu observer une augmentation de la production d'hCG sous l'effet de faibles concentrations de peroxyde d'hydrogène (<50 [micro]M), alors que des concentrations plus élevées diminuent l'activité placentaire en diminuant la sécrétion d'hCG, démontrant son action cytotoxique à plus forte dose. Ceci a également été constaté par une augmentation de l'apoptose. Le peroxyde d'hydrogène a aussi démontré ses effets sur la production par les cytotrophoblastes de facteurs pro-inflammatoires, tel le TNF-[alpha], ainsi que de son récepteur, le TNFR2, qui sont tous deux augmentés après traitement. Le peroxyde d'hydrogène semble aussi avoir une influence sur la production de médiateurs vasodilatateurs tel l'oxyde nitrique, dont la diminution est observée in vitro avec des concentrations croissantes d'H[indice inférieur 2]O[indice inférieur 2]. Le stress oxydatif dans la prééclampsie, représenté dans notre modèle in vitro par le peroxyde d'hydrogène, semble donc être central dans la physiopathologie de cette maladie, puisqu'on peut lui attribuer en partie la variation d'importants facteurs. Toutefois, les moyens de la prise en charge de cette condition pathologique doivent être soigneusement déterminés, puisque le peroxyde d'hydrogène paraît avoir tout de même un rôle physiologique important à jouer, d'où l'intérêt de parler d'équilibre oxydatif.

Regulation of the growth and differentiation of trophoblast cells is critical for successful embryo implantation and placentation. Cytokines are key players in these processes, as well as modulating the maternal immune response to prevent rejection of the conceptus. This thesis focused on the investigation of the cytokine interleukin (IL) - 33 and its receptor, ST2. ST2 has two isoforms, a functional cell surface receptor (ST2L) and a soluble decoy receptor (sST2). Previous work in this laboratory had shown that the human placenta expresses both IL-33 and sST2 at term. The aim of this thesis was to investigate IL-33 and ST2 in early pregnancy, the time when trophoblast is at its most active, with a view to better understanding their role. IL-33 and ST2 mRNA and protein were examined in 14 first trimester placentas from 6-12 weeks of gestation. IL-33 was localized to cells in the villous stroma, whereas ST2 was present in the syncytiotrophoblast, villous cytotrophoblast and the invasive extravillous cytotrophoblast of the cell columns. Secretion of sST2, but not IL-33, by the placenta was found. Investigation of pre-implantation embryos showed the presence of ST2, but not IL-33 protein. Decidualized endometrium was investigated as a potential source of IL-33 and sST2 at the maternal-fetal interface and, although mRNA for both was present, no protein could be found. The key finding was that sST2, rather than ST2L, was the predominant isoform in the placenta. This led us to reconsider the hypothesis that IL-33/ST2 interactions in the placenta are important for successful pregnancy and raised the possibility that they may have independent roles. Using trophoblast cell lines as a model, it was shown that sST2 binds to trophoblast cells, significantly inhibits their proliferation and stimulates their invasion in vitro. This is the first report of this novel role for sST2 in pregnancy. Thus these studies have shown that sST2 may play an important role in implantation and placentation through controlling trophoblast invasion.

Lopinavir (LPV) is a potent protease inhibitor specific for HIV-1. However, LPV has poor placental penetration due to substrate activity for efflux transporter by P-glycoprotein (P-gp). Since fatty acid transporters are highly expressed in the placenta during pregnancy, we designed fatty acid ester prodrug of lopinavir as substrates of fatty acid transporter in order to improve their uptake into placenta. Seven dicarboxylic acid esters of lopinavir have been made in our lab. The structures were characterized by 1H-NMR, 13C-NMR, LC-MS/MS, HRMS, IR and melting points. After making the prodrugs, an LC-MS/MS method with high specificity and sensitivity, as well as simultaneous quantitative analyses of lopinavir and SLPV, GLPV and DLPV in the BeWo cells methanol extraction was established and validated. The uptake of prodrugs (SLPV, GLPV and DLPV) in the BeWo cells was then determined. GLPV has the highest uptake followed by SLPV and then DLPV. The results suggest that the carbon length of the promoiety may have a positive relationship with the uptake. Ideal prodrugs should be stable before they reach placenta and can be hydrolyzed in the placenta and/or in fetal plasma. We did a series of stability and hydrolysis studies in human tissue fractions. The results showed that GLPV and SLPV were very stable in HIC, HLC and human adult plasma. DLPV was stable in HIC, HLC, but can be hydrolyzed in human adult plasma. GLPV and SLPV cannot be hydrolyzed in either human placenta or fetal plasma, while DLPV can be hydrolyzed in both human placenta and fetal plasma. Anti-HIV activities study of prodrugs was also conducted. The results showed that the EC50 of three prodrugs (GLPV, SLPV and DLPV) are 0.86 μM, 0.84 μM and 0.05 μM, which are much lower than 50 μM (The active drug criteria for this assay). It suggests that prodrugs have apparently anti-HIV activity. DLPV has comparable apparent anti-HIV activity to LPV (<0.02 μM). After incubation with CEM-SS cells for 6 days, almost half of DLPV was hydrolyzed into LPV. Therefore, the high anti-HIV potent of DLPV may be due to the anti-HIV activity of generated LPV.

Background: Intra-amniotic infections (IAIs) are common complications of labor and delivery. If inadequately treated, these infections can lead to significant morbidity and mortality in the mother and the fetus. Intrapartum aminoglycoside (AG) administration is recommended for the management of IAIs. AGs are known to cross the placenta and achieve bactericidal concentrations in fetal serum. However, the highest and most persistent fetal levels are achieved in renal tissue. So, the fetus may be vulnerable to the nephrotoxic effects of AGs. Megalin, a 600 kDaendocytic receptor, is responsible for the uptake of AGs into renal proximal tubular epithelial cells. This receptor is also expressed in human term placenta and it is reasonable to speculate that it is similarly involved in the placental transport of AGs. However, the mechanisms responsible for placental AG uptake and transport have not yet been characterized. Objective: To evaluate the role of megalin in the transport of AGs across human placenta. Specific aims: (1) To assess and compare megalin expression in term and preterm placental villous tissue, and (2) assess the functional activity of megalin in in vitro placental models. Methods: (1) Following IRB approval, placental tissue samples were collected from pregnant women undergoing term or preterm deliveries. Placental villous tissueswere used to quantify megalin expression by western blotting and q-PCR (2) The human choriocarcinoma cell line (BeWo cells) were grown on Transwell plates, and then megalin expression and function were assessed. Results: Megalin protein and mRNA expression were confirmed in samples of human placental villous tissues. Megalin mRNA expression declined steeply with gestational age till week 31 of gestation then it plateaued thereafter. Also, the expression in the early preterm (n=2) was six fold higher than that of both late preterm (n=3) and term placenta (n=10) (p<0.05). The uptake of 3H-gentamicin by the BeWo cells was time-dependent, saturable (Vmax=42.9 ± 4.9 nmol/mg protein/min; Km=2.93±0.68mM) and partially inhibited by megalin inhibitors. Conclusion: Megalin is expressed in human placental villous tissues as well as the BeWo cells. When grown on Transwell® plates, the BeWo cells appear to be the most appropriate model to study the in vitro transport of AGs across the apical membrane. Time, temperature and concentration dependence of gentamicin uptake in the BeWo cells indicate protein-mediated transport. The inhibition data are consistent with megalin-mediated endocytosis of AGs.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.