Preeclampsia and molar pregnancy are two devastating placental pathologies characterized by an immature proliferative trophoblast phenotype accompanied by excessive cell death. It is therefore of paramount importance to study the regulation of cell fate in the placenta, to gain a further understanding of the mechanisms that contribute to these diseases. In this dissertation we report that during normal placental development and in preeclampsia, Matador (Mtd), a pro-apoptotic member of the Bcl-2 family, has a dual function in regulating trophoblast cell proliferation and death. Importantly, we reveal a novel role of Mtd-L in promoting cyclin E1 expression and cell cycle progression. Of clinical importance, we also identify that both cyclin E1 and the CDK inhibitor p27, are increased in severe early onset preeclampsia. However, the inhibitory function of p27 in this pathology may be hampered due to its increased phosphorylation at Ser10, resulting in its nuclear export. Of equal importance, data presented demonstrate that placentae from severe early onset preeclampsia display a molecular profile distinct from late onset preeclampsia or intrauterine growth restricted pregnancies. In the final data chapter we demonstrate that Mtd is highly expressed in molar tissue, where it localizes to both apoptotic and proliferative cells. Our data suggests that an abundance of Mtd and cyclin E1 in conjunction with the low level of p27 may contribute to the hyperproliferative nature of the disorder. The body of work in this dissertation uncovers novel insights into the regulation of trophoblast cell fate. Importantly, the impact of Mtd on cyclin E1 to promote G1-S transition is a novel mechanism found to regulate trophoblast cell proliferation in normal and pathological placentation. Equally important is our identification of molecular differences between placental pathologies that may help to differentiate early and late onset preeclampsia, IUGR and molar pregnancy.

Preeclampsia is one of the most feared pregnancy complications, with a risk of maternal and fetal death and with no ideal therapy readily available. The cause of this strictly pregnancyrelated disease is still unknown and is therefore a great challenge to all researchers in the field of pregnancy-related pathophysiology. Today, the dominating theory of the origin of preeclampsia is defective initial placentation with insufficient penetration of the trophoblasts, leading to impaired maternal blood flow through narrow spiral arteries. However, the cause of this defective trophoblast behavior is not known. The maternal immune system has been proposed to have an influence on both the placentation and the subsequent systemic reactions. Therefore, it is very interesting to study the maternal immune system during preeclampsia, in hope of achieving a better understanding of this puzzling disease. Earlier studies have suggested that normal pregnancy requires a shift to a Th2/antiinflammatory type of immunity, at least directed towards the fetus and placenta, while some pregnancy complications, such as preeclampsia, could be due to a skewed Th1/proinflammatory type of immunity. However, the results from earlier studies designed to test the Th1/Th2 hypothesis in preeclampsia have not been consistent. Therefore, the aim of this thesis was to examine if established preeclampsia is associated with increased innate inflammatory responses and a deviation of adaptive responses towards Th1 when compared with normal pregnancy. Enumerations of cytokine-producing cells from peripheral blood did not show any difference in the production of IFN-γ, IL-4, IL-10 and IL-12 between women with preeclampsia and normal pregnancies. However, a decrease in the spontaneously produced levels of IL-5 was detected in cell cultures on peripheral blood mononuclear cells in women with preeclampsia. Furthermore, a decreased production of IL-10 in response to paternal antigens, believed to represent the fetus, was also detected for the preeclamptic women. Serum analysis showed increased levels of the pro-inflammatory mediators IL-6 and IL-8 during preeclampsia. Also, preeclamptic women displayed increased serum levels of the soluble IL-4 receptor, but no difference in the levels of IL-4 compared to normal pregnant women. This was an elusive finding, since the receptor was originally thought to reflect the levels of IL-4, but has recently been shown to have both agonistic and antagonistic properties on the IL-4 levels. Further studies of the local immune responses in the placenta showed no difference in the immunohistochemical staining of IL-4 and TNF-α between women with preeclampsia and women with normal pregnancies. In general, there were no hallmarks of abnormal morphology in the placental sections examined, regardless of diagnosis. In conclusion, the decreased levels of IL-10 in response to paternal antigens and the systemically increased levels of IL-6 and IL-8 suggest a specific decrease in antiinflammatory responses towards fetal antigens, together with a systemic activation of proinflammatory mediators during preeclampsia. Furthermore, the decreased production of IL-5 also indicates, at least partly, decreased Th2 responses in the established preeclampsia. / Figure 1 on page 6 is republished in the Ph.D. thesis with the kind permisson of Blackwell Publishing (http://www.blackwellpublishing.com). Figure IX on page38, figure XB on page 41, figure XI on page 46 and figure XII on page 47 are all published in the Journal of Reproductive Immunology and republished with kind permisson from Elsevier (http://www.elsevier.com/) in the Ph.D. thesis.

This study investigated whether or not there was an overall difference in the pulmonary oxidative marker, 8-isoprostane (PGF2-a), found in exhaled breath condensate, during pregnancy versus the non-pregnant state. The utility of this information was important secondary to the effect of maternal asthma on pregnancy and outcome, as it has been demonstrated in past studies that overall pregnant females with asthma have been shown to have an increased risk of exacerbation requiring medical intervention.The primary goal of this study sought to determine if there is a difference in PGF2a levels in the exhaled breath condensate of pregnant versus non-pregnant females. In order to achieve this goal a cross-sectional study was performed consisting of two groups and were compared to one another. A group of 16 healthy, non-pregnant females aged 18-35 years old was compared to a group of 6 healthy, pregnant females in their third trimester of pregnancy. Both groups exhaled breath condensate was collected and 8-isoprostane levels determined and compared to each other. Both groups compared did not report a history of environmental allergies, asthma, and smoking. The non-pregnant group showed a mean 8-isoprostane level of 11.513pg/ml (C.I. 8.7633- 14.263). The pregnant group showed a mean 8-isoprostane level of 17.34 pg/ml (C.I. -4.209-38.889).Although a crude observable difference between the means of the two groups was determined, this pilot study did not show a statistically significant difference between the means of the pregnant versus non-pregnant group when they were statistically compared. This finding is primarily due to the small sample size of both groups. A power calculation determined that each group would require 25 participants in order to establish a statistically significant difference in the 8-isoprostane levels in exhaled breath condensate. The implication is that a larger scale study is needed in order to conclusively determine if there is a statistically significant difference between the exhaled breath condensate 8-isoprostane levels in pregnant versus non-pregnant females.

Die Präeklampsie ist eine schwangerschaftsspezifische Erkrankung, deren klinische Zeichen in der Regel erst nach der 20. Schwangerschaftswoche auftreten. Behandlungsmöglichkeiten zur Verminderung von Komplikationen, wie der uterinen Wachstumsretardierung, sind durch ein spätes Erkennen des Krankheitsbildes limitiert. Ziel der Studie war es zu prüfen, ob die parallele Messung von uteriner Perfusion und der maternalen Blutplasmakonzentration der anti-/angiogenen Faktoren PlGF, sFlt-1 und sEndoglin im 2. Trimenon die prädiktive Wertigkeit der Dopplersonographie hinsichtlich der Entwicklung einer Präeklampsie erhöhen kann. Anhand der Ergebnisse weisen Frauen mit gestörter uteroplazentarer Perfusion und einem anschließend komplikationsreichen Verlauf erhöhte Werte an sFlt-1 und sEndoglin sowie erniedrigte Werte an PlGF im Vergleich zu Frauen mit normalem Schwangerschaftsausgang auf. Die zusätzliche Analyse dieser Faktoren konnte die prädiktive Fähigkeit der Dopplersonographie bezüglich einer Präeklampsie erhöhen, insbesondere bei der frühen Form mit Entbindung vor der 34. SSW. Somit können Hochrisikopatientinnen für die Entwicklung einer Präeklampsie durch die Messung von PlGF, sFlt-1 und sEndoglin frühzeitiger erfasst werden. Weitere Studien sind zur Bestimmung eines idealen Messungszeitpunktes, der optimalen Kombination der Faktoren und endgültiger Cutoffwerte notwendig.

In pregnancy, the maternal cardiovascular and placental circulation undergoes structural and functional changes to accommodate the growing fetus, but the mechanisms involved are not fully understood. Nitric oxide (NO) increases in normal pregnancy and lack of NO has been implicated in pregnancy related complications, preeclampsia and fetal growth restriction. Thus, the objective of the thesis was to determine if cardiovascular, uteroplacental and fetoplacental changes observed in human pregnancy also occur in mice and to assess the obligatory role of eNOS in mediating these changes. I showed that like humans, mice exhibit increases in maternal cardiac output, stroke volume, plasma volume, and uterine arterial blood flow, and a transient decrease in arterial pressure during pregnancy. Importantly, I showed that endothelial nitric oxide synthase (eNOS) plays an important role in promoting the progressive increase in maternal cardiac chamber dimensions and output and the enlargement of the aorta during pregnancy in mice. Another novel finding was that eNOS plays an important role in remodeling of the uterine and umbilical vasculatures during pregnancy. The remodeling of the uterine vasculatures, including the uterine and spiral arteries, were blunted in the eNOS KO mice with ko fetuses (KO(ko)) and this likely contributed to elevated vascular resistance and reduced perfusion of the uterine circulation during pregnancy. Impaired spiral artery remodeling may be caused by a deficiency in decidual uterine natural killer cells. Fetal placental vascularization was also impaired in eNOS KO(ko) mice, which likely increased vascular resistance and thereby reduced fetoplacental perfusion. Reduced vascularization may be due to decreased VEGF mRNA and protein expression in KO(ko) placentas. Decreased perfusion in both the uterine and umbilical circulations most likely contributed to elevated placental and fetal hypoxia in the eNOS KO(ko) mice. Interestingly, despite placental hypoxia, eNOS KO(ko) mice do not show the classical signs of preeclampsia including hypertension and proteinuria nor are maternal plasma sFlt1 levels elevated. Nevertheless, eNOS KO(ko) pups are growth restricted at term, and this is mainly due to the fetal genotype. These findings suggest that eNOS plays an essential role during pregnancy in remodeling of the maternal heart, aorta, and uterine and umbilical vasculatures thereby augmenting blood flow to the maternal and fetal sides of the placenta and thereby promoting fetal growth in mice.

No description available.

No description available.

HIV and hypertensive disorders in pregnancy, in particular pre-eclampsia, are the main causes of maternal mortality in South Africa. In HIV associated pre-eclampsia, it is biologically plausible that the immune activation associated with pre-eclampsia may be neutralised by the immune suppression of HIV infection. The precise aetiology of pre-eclampsia is unknown, however leptin has been implicated in its development. Leptin is an adipocyte hormone, also produced by the placenta. It has a role in the development of inflammation. Adipose tissue is reduced in HIV infected individuals, resulting in lower leptin levels with consequent impaired immune function. This study aimed to compare serum and placental leptin levels in HIV infected and uninfected normotensive and pre-eclamptic pregnancies. Since insulin levels may affect the secretion of leptin, the study also compared insulin levels in these pregnancies. Following ethical clearance and hospital permission, 180 participants were recruited during their antenatal period. The groups were HIV- normotensive (n = 30), HIV+ normotensive (n = 60), HIV– pre-eclamptic (n = 30) and HIV+ pre-eclamptic (n = 60). Blood samples were collected ante-natally and placental samples post delivery. Serum leptin and insulin levels were determined by ELISA. Placental leptin levels were determined by ELISA and immunohistochemistry with morphometric image analysis. The placental production of leptin was determined by RT PCR. There was a non-significant increase in serum leptin levels in HIV- pre-eclampsia compared to HIV- normotensive pregnancies (p = 0.42). However leptin was decreased significantly in HIV+ pre-eclampsia compared to HIV- normotensive (p = 0.03). Based on HIV status leptin levels were decreased in HIV+ groups compared to HIV- groups in both pre-eclamptic (p < 0.01) and normotensive pregnancies (p < 0.01). Insulin levels of the HIV positive groups were lower than those of the HIV negative groups (p < 0.001). Insulin levels were also decreased in pre-eclampsia compared to normotensive pregnancies, irrespective of HIV status (p = 0.02). Immunohistochemistry demonstrated an increase in immuno-reactivity of leptin in the exchange villi of pre-eclamptic compared to normotensive placentae, irrespective of HIV status (p < 0.001). Supporting this finding, ELISA also demonstrated elevated leptin levels in the placenta of pre-eclamptic compared to normotensive pregnancies (p < 0.001). Placental leptin levels were similar in both HIV positive and negative pregnancies (p = 0.36). However, the placental leptin mRNA expression was up-regulated in HIV negative pre-eclampsia (p = 0.04) but not in HIV positive pre-eclampsia (p = 1.00). In conclusion, the elevated placental leptin in pre-eclampsia, irrespective of HIV status, is consistent with hypoxia. These elevated levels are not reflected in the maternal serum which raises the possibility of decreased leptin expression by adipose tissue especially in HIV infection where serum leptin levels are decreased. This would negate the increased placental leptin expression in pre-eclampsia. Furthermore, the elevated placental leptin levels are suggestive of an autocrine role of leptin in the placenta. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2013.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Background: Leptin is a new adipose-derived hormone discovered in 1994. It is vital in energy balance and weight regulation in humans. During pregnancy the placenta is an extra source of leptin. The role of leptin in pregnancy is not established. This has generated a lot of interest in leptin research in pregnancy. Leptin is being examined in pathological states that may have origin in adipose tissue and the placenta such as pre-eclampsia, intrauterine growth restriction and obesity. Aim and Method: This study measured concentrations of serum leptin in Black African women during late pregnancy in 68 women with pre-eclampsia, 92 healthy normotensive pregnant women and in 32 healthy non-pregnant women. In each group leptin levels were compared between obese (body mass index, BMI = or > than 30 kgm-2) and lean women. Serum leptin concentrations were measured by radioimmunoassay (RIA) technique. Results: Serum leptin levels were higher in pregnancy compared to non-pregnant women (26.66+/-16.13 ng/ml, 25.89+/-15.83 ng/ml vs 17.97+/-11.98 ng/ml, p=0.02). This is due to firstly, the extra fat accumulated as part of the maternal adaptation to pregnancy and secondlv, to the placenta-derived leptin. Other pregnancy hormones such as insulin, hcG, prolactin and oestrogen may modulate the serum levels of leptin in pregnancy. Simple anthropometric parameters (weight, BMI, circumferences of the mid upper arm (MAC), waist (WC), hip (HC), and thigh (TC) and waist-hip ratio (WHR)) were used to explore the relationship between leptin concentrations and obesity. All the parameters showed a positive correlation with serum leptin concentration in all the groups with the exception of WHR. Weight and BMI showed the greatest correlation both in pregnant (r=0.61 and r=0.58, respectively, p<0.001) and non-pregnant (r=0.74 and 0.79, respectively, p<0.001) women. However we did not find a significant difference in the concentrations of leptin between women with and those without pre-eclampsia (26.66 ng/ml vs 25.89 ng/ml, p=0.95). This probably means that adiposity is the predominant factor influencing levels of leptin in pregnancy. The other factors mentioned above play only a minor role. Indeed the mean serum leptin levels were higher in obese compared to lean women in both pregnant and non-pregnant women. Conclusion: Pregnancy is a hyperleptinaemic state. There is no difference in serum leptin levels between women with pre-eclampsia and healthy normotensive pregnant women. Serum leptin concentration is largely determined by the degree of adiposity both in and outside pregnancy. / Thesis (M.Med.)-University of Natal, Durban, 2001.