Abstract Experiments in this thesis were conducted to investigate the possibility of bestowing lambs with increased resistance to gastrointestinal parasites through maternal protein and copper supplementation. Reproductive outcomes such as birth weight, haematological parameters and faecal egg counts were used as indices of possible foetal programming. This thesis involved 5 experiments. The first three experiments were done using rats as a preliminary study animal on account of their short generational intervals and high fecundity. The final two experiments involved Merino sheep. The first experiment in Chapter 4 investigated the most optimum larval dose to use in order to elicit a measurable immune response. Weaned offspring were infected with a rat nematode, Nippostrongylus brasiliensis and their response measured by faecal egg counts, parasite recovery from intestines at sacrifice, spleen weights and leucocyte numbers, especially manifested as eosinophilia. There was no significant difference in parasite rejection for rats infected with 1000 larvae/rat. When rats were infected with variable larval doses to determine the optimum dose rate, eosinophilia and spleen weight were significantly increased as dose rate increased from 500 L3 to 2,000 larvae. Based on these results, it was decided to use 1,000 larvae for each rat in Chapter 6. The experiment in Chapter 5 involved feeding diets with 5 graded concentrations of copper (Cu) ranging from deficient (1 ppm diet) to high (16 ppm diet). Rats were fed for 4 weeks before mating after which half of them were sacrificed to determine liver Cu concentrations and haematological parameters. The rest were mated and maintained on their respective Cu diets into the second trimester of pregnancy. Pregnant females were sacrificed on approximately gestational Day 10 to recover foetuses and determine the incidence of foetal defects, foetal Cu status as well as maternal liver copper status. It was determined that most morphological defects occurred for the 1 ppm foetuses and both 2 ppm and 4 ppm had similar incidences of brain enlargements. The 16 ppm copper diet was excessive evidenced by reduced liver iron status and erythrocyte counts to similar levels as for 2 ppm rats although it had no adverse effect on foetal development. Significant differences were found for liver Cu status, erythrocyte counts and spleen weights due to the copper diets. A deficient copper diet containing 1 ppm Cu (LC) and an adequate diet containing 8 ppm Cu (SC) were used for the last rat experiment in Chapter 6 which was funded by the Science and Innovation Award. The LC diets were fed for 4 weeks prior to mating. Rats were then fed LC throughout pregnancy, for the 1st trimester only or for the 1st and 2nd trimesters. Other pregnant females were fed the SC diet throughout pregnancy. Offspring were challenged with 1000 L3 N. brasiliensis and their immune responses measured. Copper deficiency at variable stages of prenatal development caused significant postnatal mortalities but had no effect on response to parasite resistance. However, significant parasite and sex effects were found for parameters such as spleen weight, eosinophilia and weight loss during infection. The foetal brain enlargement caused by the deficient 1 ppm Cu diet was determined to be reversible in vivo upon exposure to a normal 8 ppm Cu diet during gestation. Chapter 7 involved Merino ewes which were fed either a high protein diet (21%) or adequate protein diet (12%) during the first 2 trimesters of pregnancy. Production parameters measured included pregnancy weight gain, fleece yield, protein content in milk as well as birth weight of lambs but none were significantly different. After weaning, the lambs were experimentally infected with 10,000 Haemonchus contortus larvae. Barber’s pole worm is responsible for millions of dollars in production losses in the sheep industry. Responses measured were eosinophilia, faecal egg count, anaemia (PCV) and weight gain/loss during the infection period. No significant differences were found for any parameter tested except for a parasite effect on erythrocyte numbers and PCV. In Chapter 8 Merino ewes were used which were mildly Cu deficient due to grazing on pasture that was copper deficient. Control ewes were supplemented with copper oxide wire particles at mating and mid-pregnancy. The rest of the experiment was the same as for Chapter 7 in terms of Barber’s pole worm larval dose. There were no significant differences in birth weight, weaning weight or ewe fleece weights due to copper status. There were no differences in parasite resistance in the lambs due to maternal Cu status measured by live weights, eosinophil concentrations or faecal egg counts. In conclusion, foetal programming by maternal nutritional supplements for postnatal parasite resistance appears to be impossible. It may be that if a different organ was targeted, such as the spleen, the results would have been different. The thymus appears to be non-programmable during foetal development in rats and sheep. However, it was a worthwhile attempt at conferring resistance to parasites in lambs due to the urgency in combating the global problem of parasite resistance to anthelmintics and the resultant large economic losses that are experienced by the global sheep industry.

Résumé: Le surpoids et l’obésité dans la population pédiatrique sont des préoccupations grandissantes à l’échelle mondiale. Actuellement, au Canada, près de 21 % des jeunes Canadiens âgés de 2 à 5 ans présentent un surpoids et malheureusement, 6 % d’entre eux souffrent d’obésité. De plus, 80 % de ces enfants risquent d’être obèses à l’âge adulte, ce qui mène à plusieurs impacts sur la santé. Afin de prévenir l’obésité infantile, il est important d’identifier des facteurs de risques, notamment ceux se produisant tôt dans la vie. Plusieurs études ont démontré l’importance de l’environnement fœtal dans l’établissement de la santé métabolique à long terme. Le poids à la naissance a souvent été utilisé comme marqueur de l’exposition prénatale. Cependant, le poids à la naissance n’est qu’un marqueur grossier. L’adiposité à la naissance a été identifiée comme un facteur de risque plus important puisqu’elle permet de prédire de l’adiposité durant l’enfance. Les deux déterminants maternels majeurs de la croissance fœtale sont le statut pondéral et la glycémie maternelle. Récemment, une adipokine a été suggérée comme un déterminant potentiel dans la programmation fœtale de l’obésité. La leptine, qui est produite par les adipocytes, joue un rôle important dans la balance énergétique, mais elle semble aussi importante dans le développement de l’obésité postnatale. Durant la grossesse, le placenta produit une large quantité de leptine et la majorité est sécrétée du côté maternel. Appuyés par le fait que la leptine maternelle circulante est le reflet de la sécrétion placentaire de leptine, nous avons émis l’hypothèse que la leptine maternelle serait associée à l’adiposité du nouveau-né, et ce, indépendamment de la glycémie maternelle. Nous avons étudié la leptine durant l’hyperglycémie provoquée par voie orale (HGPO) chez les femmes enceintes au 2e trimestre. Nous avons montré, chez les femmes en surpoids ou obèse, qu’une plus haute leptine maternelle était lié à une adiposité néonatale augmentée à la naissance. D’un autre côté, chez les femmes minces, une glycémie élevée était liée à une adiposité néonatale augmentée. Ces associations sont indépendantes de la parité, du statut tabagique, du gain de poids durant la grossesse, des triglycérides maternels, du mode d’accouchement, du sexe du nouveau-né et de l’âge gestationnel à la naissance. Ces résultats suggèrent une régulation différentielle entre ces deux marqueurs métaboliques maternels et l’adiposité néonatale, selon le statut pondéral pré-grossesse. / Abstract: Worldwide, overweight and obesity in the pediatric population is a growing concern. Almost 21% of Canadian children aged 2 to 5 years are overweight and unfortunately, 6% of them are obese. Among those children, 80% will remain obese in adulthood leading to several health impacts. To prevent childhood obesity, we need to identify risk factors especially those occurring early in life. A particular importance was given to the fetal environment in establishing long-term metabolic health. Therefore, birth weight was often used as a marker of prenatal exposure. However, birth weight is a fairl y crude marker, and neonatal adiposity was previously identified as a stronger predictor of childhood adiposity. Two of the most important maternal determinants of fetal growth are maternal weight status and glycaemia during pregnancy. Recently, an adipoki ne have been suggested as a potential contributor to prenatal programming of obesity. Leptin is produced by adipocytes and plays an important role in energy balance and maybe on programming of postnatal obesity. During pregnancy, the placenta produces large amounts of leptin and 80% is secreted to the maternal side. Support ed by the fact that circulating maternal leptin levels reflects the placenta leptin production, our hypothesis was that maternal leptin levels are associated with neonatal adiposity, inde pendently of maternal glycaemia. We investigated levels of leptin over the course of an oral glucose tolerance test (OGTT) in pregnant women at 2nd trimester. We showed that higher maternal leptinemia is associated with greater adiposity in newborns of mot hers who were overweight/obese when entering pregnancy. While in lean women, higher glycaemia is associated with greater adiposity in newborns. These associations are independent of parity, maternal smoking status, maternal gestational weight gain, maternal triglyceride levels, delivery mode, neonate sex and gestational age at delivery. Those results suggest a differential regulation two important maternal metabolic marker and neonatal adiposity, according to maternal weight status.

<p><font face="TimesNewRomanPSMT"> <p align="left">Nicotine exposure to the fetus through tobacco smoking or nicotine replacement therapy during the whole period of gestation and lactation causes diverse effects on fetal and neonatal lung development, integrity and maturation which compromise the gas exchange function of the lungs and renders this vital organ susceptible to gradual damage and different diseases in latter life. Maternal nicotine exposure during gestation and lactation results in gradual destruction of the lung parenchyma, and this leads to the combination of many small air sacs in one bigger alveoli which is a sign of emphysema. Many researchers speculated that the way in which, nicotine causes emphysema and other damage, is by inducing the formation of many reactive oxygen species (ROS), and creating an imbalance between the oxidants and the antioxidants of the body, which is termed oxidative stress. The aim of this study was to assess the effects of nicotine exposure on the lung of the fetal and neonate rat during gestation and lactation as gas exchanger, and also to see whether the supplementation of tomato juice containing lycopene, a powerful carotenoid antioxidant could protect the lungs against these effects of maternal nicotine exposure.</p> </font></p>

<p>Nicotine exposure to the fetus through tobacco smoking or nicotine replacement therapy during the whole period of gestation and lactation causes diverse effects on fetal and neonatal lung development, integrity and maturation which compromise the gas exchange function of the lungs and renders this vital organ susceptible to gradual damage and different diseases in latter life. Maternal nicotine exposure during gestation and lactation results in gradual destruction of the lung parenchyma, and this leads to the combination of many small air sacs in one bigger alveoli which is a sign of emphysema. Many researchers speculated that the way in which, nicotine causes emphysema and other damage, is by inducing the formation of many reactive oxygen species (ROS), and creating an imbalance between the oxidants and the antioxidants of the body, which is termed oxidative stress. The aim of this study was to assess the effects of nicotine exposure on the lung of the fetal and neonate rat during gestation and lactation as gas exchanger, and also to see whether the supplementation of tomato juice containing lycopene, a powerful carotenoid antioxidant could protect the lungs against these effects of maternal nicotine exposure. In this study pregnant rats have been divided into 4 groups: a group which received nicotine (1mg/kg body weight/day) subcutaneously, a group that received the tomato juice only (6mg/kg body weight/day per os), a third group that received the combination of tomato juice ( 6mg /kg body weight/ day per os) and nicotine (1mg/kg body weight /day subcutaneously ) . The control group that received saline (1mg/kg body weight /day) subcutaneously and water. The injections were done during pregnancy and lactation until weaning at postnatal day 21. The results showed that maternal nicotine exposure during gestation and lactation leads to a gradual damage of the lung parenchyma and slower formation of the alveoli during the equilibrated phase of the lung growth leading to a decrease in the internal surface area required for gas exchange. Supplementation with tomato juice during gestation and lactation prevents all the adverse effects of maternal nicotine exposure on the lungs of the offspring. Since nicotine induce an increase in the oxidant levels of the mother and the fetus, my results imply that lycopene protected the lungs of the offsprings against the oxidants and thus against changes in the program that controls lung development as the animals age. This is supported by the observation that at postnatal day 84 the antioxidant.</p>

<p><font face="TimesNewRomanPSMT"> <p align="left">Nicotine exposure to the fetus through tobacco smoking or nicotine replacement therapy during the whole period of gestation and lactation causes diverse effects on fetal and neonatal lung development, integrity and maturation which compromise the gas exchange function of the lungs and renders this vital organ susceptible to gradual damage and different diseases in latter life. Maternal nicotine exposure during gestation and lactation results in gradual destruction of the lung parenchyma, and this leads to the combination of many small air sacs in one bigger alveoli which is a sign of emphysema. Many researchers speculated that the way in which, nicotine causes emphysema and other damage, is by inducing the formation of many reactive oxygen species (ROS), and creating an imbalance between the oxidants and the antioxidants of the body, which is termed oxidative stress. The aim of this study was to assess the effects of nicotine exposure on the lung of the fetal and neonate rat during gestation and lactation as gas exchanger, and also to see whether the supplementation of tomato juice containing lycopene, a powerful carotenoid antioxidant could protect the lungs against these effects of maternal nicotine exposure.</p> </font></p>

<p>Nicotine exposure to the fetus through tobacco smoking or nicotine replacement therapy during the whole period of gestation and lactation causes diverse effects on fetal and neonatal lung development, integrity and maturation which compromise the gas exchange function of the lungs and renders this vital organ susceptible to gradual damage and different diseases in latter life. Maternal nicotine exposure during gestation and lactation results in gradual destruction of the lung parenchyma, and this leads to the combination of many small air sacs in one bigger alveoli which is a sign of emphysema. Many researchers speculated that the way in which, nicotine causes emphysema and other damage, is by inducing the formation of many reactive oxygen species (ROS), and creating an imbalance between the oxidants and the antioxidants of the body, which is termed oxidative stress. The aim of this study was to assess the effects of nicotine exposure on the lung of the fetal and neonate rat during gestation and lactation as gas exchanger, and also to see whether the supplementation of tomato juice containing lycopene, a powerful carotenoid antioxidant could protect the lungs against these effects of maternal nicotine exposure. In this study pregnant rats have been divided into 4 groups: a group which received nicotine (1mg/kg body weight/day) subcutaneously, a group that received the tomato juice only (6mg/kg body weight/day per os), a third group that received the combination of tomato juice ( 6mg /kg body weight/ day per os) and nicotine (1mg/kg body weight /day subcutaneously ) . The control group that received saline (1mg/kg body weight /day) subcutaneously and water. The injections were done during pregnancy and lactation until weaning at postnatal day 21. The results showed that maternal nicotine exposure during gestation and lactation leads to a gradual damage of the lung parenchyma and slower formation of the alveoli during the equilibrated phase of the lung growth leading to a decrease in the internal surface area required for gas exchange. Supplementation with tomato juice during gestation and lactation prevents all the adverse effects of maternal nicotine exposure on the lungs of the offspring. Since nicotine induce an increase in the oxidant levels of the mother and the fetus, my results imply that lycopene protected the lungs of the offsprings against the oxidants and thus against changes in the program that controls lung development as the animals age. This is supported by the observation that at postnatal day 84 the antioxidant.</p>

Magister Scientiae (Medical Bioscience) - MSc(MBS) / Nicotine exposure to the fetus through tobacco smoking or nicotine replacement therapy during the whole period of gestation and lactation causes diverse effects on fetal and neonatal lung development, integrity and maturation which compromise the gas exchange function of the lungs and renders this vital organ susceptible to gradual damage and different diseases in latter life. Maternal nicotine exposure during gestation and lactation results in gradual destruction of the lung parenchyma, and this leads to the combination of many small air sacs in one bigger alveoli which is a sign of emphysema. Many researchers speculated that the way in which, nicotine causes emphysema and other damage, is by inducing the formation of many reactive oxygen species (ROS), and creating an imbalance between the oxidants and the antioxidants of the body, which is termed oxidative stress. The aim of this study was to assess the effects of nicotine exposure on the lung of the fetal and neonate rat during gestation and lactation as gas exchanger, and also to see whether the supplementation of tomato juice containing lycopene, a powerful carotenoid antioxidant could protect the lungs against these effects of maternal nicotine exposure. In this study pregnant rats have been divided into 4 groups: a group which received nicotine (1mg/kg body weight/day) subcutaneously, a group that received the tomato juice only (6mg/kg body weight/day per os), a third group that received the combination of tomato juice ( 6mg /kg body weight/ day per os) and nicotine (1mg/kg body weight /day subcutaneously ) . The control group that received saline (1mg/kg body weight /day) subcutaneously and water. The injections were done during pregnancy and lactation until weaning at postnatal day 21. The results showed that maternal nicotine exposure during gestation and lactation leads to a gradual damage of the lung parenchyma and slower formation of the alveoli during the equilibrated phase of the lung growth leading to a decrease in the internal surface area required for gas exchange. Supplementation with tomato juice during gestation and lactation prevents all the adverse effects of maternal nicotine exposure on the lungs of the offspring. Since nicotine induce an increase in the oxidant levels of the mother and the fetus, my results imply that lycopene protected the lungs of the offsprings against the oxidants and thus against changes in the program that controls lung development as the animals age. This is supported by the observation that at postnatal day 84 the antioxidant. / South Africa

La restriction de croissance intrautérine (RCIU) est associée à l’apparition de maladies à l’âge adulte et le phénotype de la condition pathologique peut être différent selon le sexe. Notre laboratoire a développé un modèle de RCIU chez le rat en administrant une diète faible en sodium lors du dernier tiers de la gestation entraînant une réduction de l’expansion volémique maternelle et de la perfusion utéroplacentaire. L'activité rénine et la concentration d'aldostérone plasmatique sont augmentées chez la mère et les foetus RCIU. Antérieurement, notre laboratoire a démontré une augmentation de l’expression génique et protéique rénale de la Na+-K+-ATPase-α1 uniquement chez les foetus femelles RCIU. Ainsi, nous émettons l’hypothèse que la diminution du volume circulant chez la rate gestante entraîne une augmentation et une expression différentielle, selon le sexe, des éléments de la cascade de signalisation du récepteur des minéralocorticoïdes (MR) dans les reins de foetus RCIU. L’expression des gènes est réalisée par qRT-PCR et celle des protéines par immunobuvardage de type Western. Bien que les résultats démontrent que la transcription génique de SGK1, α-ENaC et GILZ soit augmentée dans les reins de foetus RCIU, l’expression protéique de SGK1, pSGK1(Thr 256) et α-ENaC est similaire à celle des témoins. La protéine GILZ est indétectable. Pour CNKSR3, aucune différence de l’ARNm ou de la protéine n’a été observée entre les deux groupes. Par contre, même si l’expression génique du MR n’est pas différente, l’expression protéique est diminuée chez les RCIU. Aucun effet du sexe n’a été observé. En conclusion, l’augmentation d'aldostérone plasmatique chez les foetus ayant subi une RCIU stimule la transcription des gènes associés à la voie de réabsorption sodique, mais la quantité protéique demeure inchangée. Ceci suggère qu’il peut avoir des mécanismes de régulation post-transcriptionnelle ou une dégradation accélérée des protéines. Malgré la pertinence du sexe dans le développement de maladies, le sexe n’influence pas l’expression des composantes de la voie de rétention sodique chez le foetus. Il serait important de suivre cette voie en fonction de l’âge et de corréler les expressions génique et protéique avec l’apparition de maladies. / Intrauterine growth restriction (IUGR) contributes to the development of diseases in adulthood, of which some are influenced by sex. Our laboratory has developed an IUGR model in the rat by administering a low-sodium diet during the last third of gestation which leads to a reduced volume expansion and uteroplacental perfusion. Plasma renin activity (PRA) and aldosterone concentration are increased in IUGR dams and foetuses. Previously, our laboratory has shown that gene and protein expression of Na+-K+-ATPase-α1 was increased solely in female IUGR kidneys. Therefore, we hypothesize that the reduced maternal volume will result in an increase and differential expression, influenced by foetal sex, of elements from the mineralocorticoid receptor (MR) pathway. Gene expression is determined by qRT-PCR and for protein, Western blotting is performed. Although results show that gene expression of SGK1, α-ENaC and GILZ is increased in IUGR foetal kidneys, protein expression for SGK1, pSGK1 (Thr256), and α-ENaC is similar to controls. GILZ protein is not detected. For CNKSR3, no difference in mRNA or protein expression is observed between the groups. Gene expression of MR is unchanged, while its protein expression is decreased in IUGR foetuses. In conclusion, the increase in plasma aldosterone in IUGR foetuses stimulates gene transcription of several components of the sodium reabsorption pathway without affecting protein expression. These results suggest that there may be post-transcriptional regulation or a higher protein turnover. Despite the importance of biological sex in the development of disease, it did not affect the expression of elements from the sodium reabsorption pathway in the foetus. It would be important to verify this same pathway in animals of different ages to correlate gene and protein expression with the appearance of diseases.

No description available.

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.