Objetivo: Analisar através de metodologia molecular a microbiota fecal de recém-nascidos (RN) saudáveis, em aleitamento materno exclusivo. Materiais e métodos: Amostras fecais de dez RN foram avaliadas no 2º, 7º e 30º dias de vida (DV), através de sequenciamento do 16S rDNA bacteriano. Real-time PCR para bifidobacterias foi empregado nas amostras de 30 dias. Resultados: A diversidade bacteriana fecal aumentou do 2º para o 30º DV. E. coli predominou no 2º e 7º DV, e Clostridium no 30º DV. Usando real-time PCR, bifidobacterias foram identificadas em todas as amostras de 30 dias. Conclusão: Enterobacterias predominaram na primeira semana de vida. Aos 30 DV observou-se uma maior diversidade bacteriana, com predomínio de Clostridium.. A técnica inicial não permitiu identificar bifidobacterias. / Purpose: To evaluate by molecular methodology the fecal microbiota of healthy newborns, exclusively breastfed. Materials and methods: Fecal samples from ten neonates were analyzed on 2nd, 7th and 30th day of life, using 16S rDNA sequencing and real-time PCR for bifidobacteria. Results: The fecal bacteria diversity increased from the second to the 30th day of life. E. coli was predominant in the fecal samples from the 2nd and 7th day of life, and Clostridium.in the samples of the 30th day. Using real-time PCR bifidobacteria were identified in all 30th day samples. Conclusion: Enterobacteria were predominant in the first week of life. On 30th day of life a greater bacterial diversity was observed with predominance of Clostridium. The initial technique didnt allow the identification of bifidobacteria.

Em Medicina Veterinária, os avanços em Neonatologia são escassos quando comparados aos da Medicina Humana. Dentre as possíveis causas para esta situação atual destacam-se as particularidades fisiológicas deste período. Os objetivos do presente estudo foram: estabelecer os valores normais de algumas variáveis laboratoriais de neonatos nascidos de parto eutócico, identificar eventuais alterações metabólicas maternas e dos neonatos nascidos em diferentes condições obstétricas, verificar os efeitos da administração de ocitocina sob variáveis neonatais e maternas e mensurar os níveis de cortisol materno e neonatal como forma de estudar as diferentes situações de estresse no momento do parto. Vinte e nove fêmeas caninas foram alocadas em 3 grupos, de acordo com o tipo de parto: eutocia (grupo 1), distocia corrigida por manobras obstétricas ou cesariana (grupo 2) e indução de contrações uterinas com ocitocina (grupo 3). Cinqüenta e um neonatos foram avaliados por meio do sistema Apgar e temperatura corpórea ao nascimento, 5 minutos e 1 hora após o nascimento, bem como por avaliação hemogasométrica, dosagem de cortisol e glicemia ao nascimento e após 1 hora. A avaliação materna constituiu no controle da pressão arterial, monitorização cardíaca, glicemia e dosagem de cortisol em momentos pontuais no pré, intra e pós-parto. Os neonatos dos distintos grupos apresentaram acidose mista associada à hipóxia ao nascimento, com maior comprometimento metabólico nos filhotes do grupo 3. Após 1 hora, recuperaram-se do componente respiratório, mantendo apenas o quadro de acidose metabólica por maior comprometimento da hipóxia. A avaliação neonatal pelo escore Apgar demonstrou que filhotes do grupo 2 nascem em maior depressão que neonatos dos grupos 1 e 3, porém todos apresentam adequada recuperação após 1 hora. Nas parturientes, a administração de ocitocina favoreceu a elevação da pressão arterial para níveis normais durante o trabalho de parto, bem como o aumento da glicemia. Neonatos nascidos por manobra obstétrica ou cesariana apresentaram maior concentração de cortisol plasmático ao nascimento, em comparação aos grupos 1 e 3. Contudo, todos os neonatos apresentaram redução significativa dos níveis de cortisol após 1 hora do nascimento. Por outro lado, foi possível verificar maior concentração sérica deste hormônio após o término do parto nas fêmeas submetidas à infusão de ocitocina. Em conclusão, a administração de ocitocina é responsável por maiores alterações metabólicas em neonatos; na parturiente, a administração de ocitocina promove alterações na pressão arterial, glicemia e aumento da liberação de cortisol; a manobra obstétrica ou cesariana promove maior estresse neonatal ao nascimento. / Studies accomplishing canine neonatology are scarce in Veterinary Medicine comparing to Human Neonatology due to the particularity of this refered period. The aims of the present study were to establish standard laboratorial values of the canine neonate, identify metabolic changes of bitches and neonates born under different obstetric conditionsl, verify the consequences of dystocia treated medically by oxytocin administration on maternal and neonatal variables and to measure maternal and neonatal cortisol levels on distinc stress situations during parturition. Twenty nine canine females were allocated into 3 groups according to the obstetric conditions: eutocia (group 1; n=10), manipulative obstetric assistance or cesarean section (group 2; n=10) and maternal dystocia treated with oxytocin (group 3; n=9). Fifty one neonates were submitted to a clinical evaluation by Apgar scoring and body temperature measurement immediately after birth, at 5 and 60 minutes postnatal; and hemogasometric evaluation, blood glucose and cortisol assay immediately after birth and 60 minutes postnatal. Maternal noninvasive arterial blood pressure, blood glucose and cardiac monitoring were peformed during the first stage of labor, intra-partum, immediately after the last puppy was born and 1 hour later. Neonates from distinct groups showed mixed acidosis in addition to hypoxemia at birth. Neonates remained under metabolic acidosis even after 1 hour of birth due to a detrimental effect on hypoxia. Comparing the results among groups, puppies from group 2 showed significantly lower Apgar score at birth. However, 1 hour later all neonates showed full recovery. Dams subjected to oxytocin infusion showed an increase in blood pressure, hence switching to a normotension status and also presented higher glucose level during parturition. Manipulative obstetric assistance or cesarean section arised neonatal cortisol levels at birth. However, all neonates exhibited significantly lower cortisol concentration after 1 hour of birth. Bitches of group 3 showed significantly higher cortisol level immediatly after whelping. In conclusion, dystocia treated medically by oxytocin infusion resulted in more intense metabolic alterations compared to neonates born under eutocia; oxytocin administration promotes blood pressure enhance, glucose alterations and increase in maternal stress; manipulative obstetric assistance or cesarean section increased neonatal cortisol release at birth.

Estima-se que a mortalidade neonatal canina nas primeiras semanas de vida seja de 30%, em razão de diversas causas, dentre elas falhas de assistência neonatal. Em Medicina Humana, protocolos de assistência cardio-respiratória ao recém-nascido estão bem estabelecidos e são utilizados de rotina. Porém, os cuidados direcionados aos neonatos debilitados em Medicina Veterinária são, em geral, empíricos e passíveis de causar traumas e contusões. Deste modo, objetivou-se comparar o padrão do aparelho respiratório ao nascimento e a evolução durante a primeira hora de vida em neonatos nascidos em eutocia via vaginal ou cesariana eletiva; propor um protocolo de conduta para a avaliação do aparelho respiratório de neonatos nascidos em eutocia ou cesariana, por meio da auscultação cardio-torácica, do escore Apgar, hemogasometria, avaliação radiográfica pulmonar e da determinação do surfactante no líquido amniótico; relacionar o exame clínico geral com a avaliação específica do aparelho respiratório; estabelecer a análise de maior sensibilidade e especificidade na identificação de distúrbios respiratórios neonatais; quantificar os fosfolipídeos lecitina (L) e esfingomielina (E) no líquido amniótico; estabelecer a relação L/E, como indício de maturidade pulmonar. Utilizou-se 41 neonatos divididos em 2 grupos conforme a condição obstétrica: eutocia (1) ou cesariana eletiva (2). Foram avaliados o escore Apgar, temperatura corpórea e exame físico completo aos 0, 5 e 60 minutos pós-natal; hemogasometria venosa aos 0 e 60 minutos do nascimento e padrão radiográfico pulmonar ao nascimento. Houve significativo aumento dos valores de Apgar no decorrer da primeira hora de vida. Entretanto, o grupo 2 apresentou escore inferior ao nascimento e após 5 minutos. A temperatura corpórea neonatal apresentou significativa queda ao longo da primeira hora de vida, para ambos os grupos, com hipotermia após 5 e 60 minutos do nascimento. A auscultação pulmonar indicou irregularidade do padrão respiratório, presença de ruído respiratório de moderado a intenso e episódios de agonia respiratória, com evolução satisfatória ao longo da primeira hora de vida para ambos os grupos. Filhotes nascidos de cesariana apresentaram maior percentual de alterações radiográficas, com moderada a intensa opacificação pulmonar difusa, com pouca ou nenhuma definição da silhueta cardíaca e luz dos brônquios principais. Ao nascimento e após 1 hora, todos os neonatos apresentaram acidemia, sendo esta do tipo mista para o grupo 1 e do tipo respiratória para o grupo 2. Após 60 minutos houve parcial evolução do desequilíbrio ácido-básico em ambos os grupos. Não houve diferença estatística entre a relação L/E dos grupos 1 e 2 com valores de 7,29 (±3,55) e 5,89 (±4,87), respectivamente. Conclui-se que o padrão de análise do aparelho respiratório neonatal variou conforme a condição obstétrica; as variáveis de maior sensibilidade e especificidade para identificação de neonatos com distúrbios respiratórios ao nascimento foram auscultação torácica associada à avaliação hemogasométrica das variáveis pH e pCO2; os fosfolipídeos lecitina e esfingomielina presentes no líquido amniótico foram quantificados e a relação L/E estabelecida e indicou maturidade pulmonar independente da condição obstétrica. / Technical and scientific deficit related to veterinary neonatology is conspicuous. It is known that the canine mortality rate is up to 30% in the first weeks of life. In Human Medicine, neonatal cardio-respiratory assistance is well established and widely used. Thus, the objectives of the present study were to compare the respiratory system pattern at birth and its evolution during the first hour of life in puppies born through eutocia or cesarian section; to standardize neonatal respiratory system assessment under distinct obstetrics conditions; to correlate clinical general variables to the specific respiratory ones; to identify the most sensible and specific variables in order to attain neonatal respiratory diagnosis; to quantify the phospholipids lecithin (L) and sphingomielin (S) in amniotic fluid; to establish the L/S ratio and its correlation with lung maturity. Forty-one canine neonates were allocated into 2 groups according to the whelping condition: group 1 - eutocia and group 2 - elective cesarean section. The following assessments were performed at 0, 5 and 60 minutes after birth: Apgar score and rectal temperature. Venous hemogasometric evaluation was attained after birth and 1 hour later. Lung x-ray was performed between 0 and 5 minutes of life. Group 2 neonates showed lower vitality, with Apgar score significantly inferior at birth and after 5 minutes. Nevertheless, there was full satisfactory recovery at 5 minutes in both groups, with the Apgar score superior to 7. There was a significant reduction in rectal temperature with hypothermia at 5 and 60 minutes of birth in both groups. Respiratory pattern was irregular at lung auscultation, with mild to moderate sounds, but all neonates evolved properly among the first hour of life. Lung x-rays indicated relevant alterations in 17% of the puppies of group 1 and 30% of group 2. Cardiac silhouette and the main caudal bronchi were clearly visualized and the image of the thymus appeared like an enlarged domed volume in cranial mediastin, adjacent to the heart. The radiographic findings ranged from mild to moderate diffuse or restricted opacification of pulmonary parenchyma. Little or no definition of the cardiac silhouette, the main bronchi and the vagueness of the thymus were all findings consistent with pulmonary edema. All puppies presented acidemia at 0 and 60 minutes after birth, with partial recovery of the acid-base disorder in both groups during the first hour of life. L/S ratio was 7,29 (±3,55) for group 1 and 5,89 (±4,87) for group 2, with no statistical difference between them. In conclusion, obstetric condition influences neonatal respiratory pattern evaluation; lung auscultation associated with pH and pCO2 hemogasometric values, which were more sensible and specific to identify respiratory disorders at birth; lecithin and sphingomielin were quantified in the amniotic fluid; L/S ratio was established and indicated lung maturity regardless of the whelping condition.

Objetivo: Analisar através de metodologia molecular a microbiota fecal de recém-nascidos (RN) saudáveis, em aleitamento materno exclusivo. Materiais e métodos: Amostras fecais de dez RN foram avaliadas no 2º, 7º e 30º dias de vida (DV), através de sequenciamento do 16S rDNA bacteriano. Real-time PCR para bifidobacterias foi empregado nas amostras de 30 dias. Resultados: A diversidade bacteriana fecal aumentou do 2º para o 30º DV. E. coli predominou no 2º e 7º DV, e Clostridium no 30º DV. Usando real-time PCR, bifidobacterias foram identificadas em todas as amostras de 30 dias. Conclusão: Enterobacterias predominaram na primeira semana de vida. Aos 30 DV observou-se uma maior diversidade bacteriana, com predomínio de Clostridium.. A técnica inicial não permitiu identificar bifidobacterias. / Purpose: To evaluate by molecular methodology the fecal microbiota of healthy newborns, exclusively breastfed. Materials and methods: Fecal samples from ten neonates were analyzed on 2nd, 7th and 30th day of life, using 16S rDNA sequencing and real-time PCR for bifidobacteria. Results: The fecal bacteria diversity increased from the second to the 30th day of life. E. coli was predominant in the fecal samples from the 2nd and 7th day of life, and Clostridium.in the samples of the 30th day. Using real-time PCR bifidobacteria were identified in all 30th day samples. Conclusion: Enterobacteria were predominant in the first week of life. On 30th day of life a greater bacterial diversity was observed with predominance of Clostridium. The initial technique didnt allow the identification of bifidobacteria.

Le Syndrome de Prader Willi (SPW) est une pathologie neurodéveloppementale d’origine génétique présentant un tableau clinique complexe et évoluant avec l’âge.Elle est caractérisée par des déficits sensori-moteurs présents dès la naissance se manifestant par une hypotonie, une absence du réflexe de succion et des troubles respiratoires incluant des apnées obstructives et centrales constituant la première cause de mortalité. Les patients présentent un certain degré d’altération cognitive et un déficit de comportement associé aux troubles du spectre autistique (TSA). Des déficits sensoriels, se manifestent dès la naissance et sont caractérisés par un seuil élevé à la douleur, une altération de la thermosensibilité et de la thermorégulation se manifestant par des épisodes d’hyper- ou d’hypothermie pouvant être fatals chez le nourrisson. Ces déficits sont une caractéristique fondamentale du diagnostic des TSA et sont retrouvées chez 90% des patients autistes. Mon travail de thèse a consisté à étudier la physiopathologie de la fonction respiratoire et la thermosensibilité néonatales et leur altération dans la pathologie neurodéveloppementale. Ces études ont été rendues possibles grâce à l’utilisation de deux modèles murins:les Ndn-/- et Ml2+/-p.Ndn est impliqué dans le SPW et l’étude des souris Ndn-/-,a permis de décrypter l’origine des déficits sérotoninergiques responsables des troubles respiratoires.Ml2,est impliqué dans le SPW et le syndrome de Schaaf Yang (SSY) et l’investigation des souris Ml2+/-p a mis en évidence l’existence d’un déficit de thermosensibilité néonatale et démontré l’implication du système ocytocinergique dans la modulation de cette fonction sensorielle. / Prader Willi Syndrome (PWS) is a neurodevelopemental genetic disease with a symptomatology which evolves with age. This pathology is mainly characterized by sensory motor defects at birth such as severe infantile hypotonia with poor suck and failure to thrive and respiratory disturbances including both obstructive and central sleep apnea which represent the most common cause of death. PWS patients also have some cognitive impairment and behavioral disturbances, overlapping with autism spectrum disorder (ASD). Sensory deficits, are already present at birth and are characterized by high pain threshold and a defect in thermosensibility and thermoregulation manifested by episode of hypo- or hyperthermia which can be fatal in newborns. Moreover, these deficits are a core aspect of ASD affecting 90 % of children. My thesis work consisted in studying the pathophysiology of respiratory function during the early postnatal stages as well as neonatal thermosensitivity and its alteration in neurodevelopmental pathology. These studies were made possible by the use of two mouse models: Ndn-/- and Magel2+/-p mice. Ndn is involved in PWS and summarizing the respiratory disorders found in patients. Ml2 is involved in both SPW and Schaaf Yang syndrome (SYS), a recently discovered pathology overlapping with ASD. Ndn-/-mice allowed me to decipher the underlying mechanism behind the serotonin deficits responsible for respiratory disorders, thus allowing me to develop an effective therapeutic strategy. The investigation of Ml2+/-p mice revealed neonatal cool sensitivity deficit and demonstrated the involvement of the oxytocinergic system in the modulation of this sensory function.

Background: Maternal perinatal mental health has been shown to be associated with adverse consequences for the mother and the child. However, studies considering the effect of DSM-IV anxiety disorders beyond maternal self-perceived distress during pregnancy and its timing are lacking. Aims: To examine the role of maternal anxiety disorders with an onset before birth and self-perceived distress during pregnancy for unfavourable maternal, obstetric, neonatal and childhood outcomes. Study design: DSM-IV mental disorders and self-perceived distress of 992 mothers as well as obstetric, neonatal and childhood outcomes of their offspring were assessed in a cohort sampled from the community using the Munich-Composite International Diagnostic Interview. Logistic regression analyses revealed associations (odds ratios) between maternal anxiety disorders and self-perceived distress during pregnancy with maternal depression after birth and a range of obstetric, neonatal and childhood psychopathological outcomes. Results: Lifetime maternal anxiety disorders were related to offspring anxiety disorders, but not to offspring externalizing disorders. Analyses focussing on maternal DSM-IV anxiety disorders before birth yielded associations with incident depression after birth. In addition, self-perceived distress during pregnancy was associated with maternal depression after birth, preterm delivery, caesarean section, separation anxiety disorder, ADHD, and conduct disorder in offspring. Conclusion: Findings confirm the transmission of anxiety disorders from mother to offspring. Apart from maternal anxiety, self-perceived distress during pregnancy also emerged as a putative risk factor for adverse outcomes. The finding that maternal anxiety disorders before birth yielded less consistent associations, suggests that self-perceived distress during pregnancy might be seen as a putative moderator/mediator in the familial transmission of anxiety.

No description available.

A world-wide series of epidemiological studies has demonstrated that there is an association between being born small and the risk of visceral obesity, a more central deposition of subcutaneous fat and insulin resistance in adult life. In the lamb, intrauterine growth restriction (IUGR) results in a low birth weight and an increased visceral fat mass by 45d of postnatal life. In this thesis I have investigated the effect of IUGR on adipose tissue development and function during fetal and early postnatal life in the sheep. IUGR was induced by removal of the majority of endometrial caruncles in non pregnant ewes prior to mating which resulted in the subsequent placental restriction of fetal growth (PR). Fetal blood samples were collected from 116d gestation and visceral perirenal adipose tissue (PAT) collected from PR and control fetuses at 145d. In lambs IUGR was defined as a birth weight less than 2 standard deviations below the mean of a cohort of singleton Merino lambs. Blood samples were collected throughout the first 3 weeks of life and PAT and subcutaneous adipose tissue (SAT) was collected at 21 d. It was determined whether IUGR alters the expression of genes which regulate adipogenesis (IGF1, IGFR1, IGF2, IGFR2, PPARy, and RXRα), adipocyte metabolism (LPL, G3PDH, GAPDH) and adipokine signalling (leptin, adiponectin) in adipose tissue depots before and after birth using qRT-PCR. PR fetuses were hypoglycaemic, hypoinsulinaemic, hypoxic, and had a lower body weight than Control fetuses. The expression of both IGF1 and leptin mRNA in PAT, the major fetal adipose depot, was lower in the PR fetuses, although there was no difference in the expression of other adipokine or adipogenic genes in PAT between PR and control fetuses. Thus restriction of placental and hence fetal substrate supply results in decreased IGF1 and leptin expression in fetal visceral adipose tissue which may alter the functional development of the perirenal fat depot and contribute to altered leptin signalling in the growth restricted newborn and the subsequent emergence of an increased visceral adiposity. At 21d of postnatal life there was no increase in the relative mass of perirenal or subcutaneous fat in IUGR lambs compared with controls. Thus, this study has investigated the effect of IUGR on the development of adipose tissue prior to the development of an obese phenotype. At 21d of life there was a sex specific effect of IUGR on the expression of PPARy and leptin mRNA in perirenal visceral fat such that PPARy and leptin mRNA expression was decreased in male IUGR lambs, but not females. Interestingly PAT mass was greater in females than males, independent of birth weight. Plasma insulin concentrations during the first 24h after birth predicted the size of the adipocytes and expression of adiponectin in visceral adipose tissue in both males and females at 21d. Thus, the nutritional environment before, and immediately after birth, may program adipocyte growth and gene expression in visceral adipose tissue. The differential effect of sex and birth weight on PPARy and leptin expression in visceral fat may be important in the subsequent development of visceral obesity and the insulin resistant phenotype in later life. At 21d of life there was no difference between Control and IUGR lambs in the relative mass of subcutaneous fat, or the expression of PPARy, RXRα, leptin, adiponectin, LPL, G3PDH, and GAPDH in subcutaneous fat at 21d of life. We have shown that the growth of the subcutaneous fat depot is related to plasma glucose, insulin and leptin concentrations, and to the development of perirenal fat. Thus, in contrast to perirenal adipose tissue, the postnatal, but not the fetal nutritional environment, programs subcutaneous adipocyte growth and gene expression. This thesis speculates that there may be a factor secreted from visceral fat that influences the development of the subcutaneous fat depot. At 21d of life there was also an effect of sex, but not IUGR, on the expression of IGF mRNA in adipose tissue. Male lambs had a higher expression of IGF1 mRNA in both PAT and SAT, and a higher expression of IGF1R and IGF2R in SAT compared with female lambs. It is likely that these differences in IGF mRNA levels reflect sexual dimorphism of the GH-IGF axis. When male and female lambs were combined there was a higher expression of IGF1 mRNA in SAT compared with PAT, and a higher expression of IGF2, IGF1R and IGF2R mRNA in PAT compared with SAT. These differences in IGF mRNA expression provide a potential mechanism to explain the sex and depot specific variations in mitogenic potency of IGF1 and proliferative capacities of preadipocytes, the regional variation in adipocyte metabolism, and the difference in incidence of visceral obesity between men and women in adult life. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1347421 / Thesis (Ph.D.) - University of Adelaide, School of Molecular and Biomedical Science, 2008

A world-wide series of epidemiological studies has demonstrated that there is an association between being born small and the risk of visceral obesity, a more central deposition of subcutaneous fat and insulin resistance in adult life. In the lamb, intrauterine growth restriction (IUGR) results in a low birth weight and an increased visceral fat mass by 45d of postnatal life. In this thesis I have investigated the effect of IUGR on adipose tissue development and function during fetal and early postnatal life in the sheep. IUGR was induced by removal of the majority of endometrial caruncles in non pregnant ewes prior to mating which resulted in the subsequent placental restriction of fetal growth (PR). Fetal blood samples were collected from 116d gestation and visceral perirenal adipose tissue (PAT) collected from PR and control fetuses at 145d. In lambs IUGR was defined as a birth weight less than 2 standard deviations below the mean of a cohort of singleton Merino lambs. Blood samples were collected throughout the first 3 weeks of life and PAT and subcutaneous adipose tissue (SAT) was collected at 21 d. It was determined whether IUGR alters the expression of genes which regulate adipogenesis (IGF1, IGFR1, IGF2, IGFR2, PPARy, and RXRα), adipocyte metabolism (LPL, G3PDH, GAPDH) and adipokine signalling (leptin, adiponectin) in adipose tissue depots before and after birth using qRT-PCR. PR fetuses were hypoglycaemic, hypoinsulinaemic, hypoxic, and had a lower body weight than Control fetuses. The expression of both IGF1 and leptin mRNA in PAT, the major fetal adipose depot, was lower in the PR fetuses, although there was no difference in the expression of other adipokine or adipogenic genes in PAT between PR and control fetuses. Thus restriction of placental and hence fetal substrate supply results in decreased IGF1 and leptin expression in fetal visceral adipose tissue which may alter the functional development of the perirenal fat depot and contribute to altered leptin signalling in the growth restricted newborn and the subsequent emergence of an increased visceral adiposity. At 21d of postnatal life there was no increase in the relative mass of perirenal or subcutaneous fat in IUGR lambs compared with controls. Thus, this study has investigated the effect of IUGR on the development of adipose tissue prior to the development of an obese phenotype. At 21d of life there was a sex specific effect of IUGR on the expression of PPARy and leptin mRNA in perirenal visceral fat such that PPARy and leptin mRNA expression was decreased in male IUGR lambs, but not females. Interestingly PAT mass was greater in females than males, independent of birth weight. Plasma insulin concentrations during the first 24h after birth predicted the size of the adipocytes and expression of adiponectin in visceral adipose tissue in both males and females at 21d. Thus, the nutritional environment before, and immediately after birth, may program adipocyte growth and gene expression in visceral adipose tissue. The differential effect of sex and birth weight on PPARy and leptin expression in visceral fat may be important in the subsequent development of visceral obesity and the insulin resistant phenotype in later life. At 21d of life there was no difference between Control and IUGR lambs in the relative mass of subcutaneous fat, or the expression of PPARy, RXRα, leptin, adiponectin, LPL, G3PDH, and GAPDH in subcutaneous fat at 21d of life. We have shown that the growth of the subcutaneous fat depot is related to plasma glucose, insulin and leptin concentrations, and to the development of perirenal fat. Thus, in contrast to perirenal adipose tissue, the postnatal, but not the fetal nutritional environment, programs subcutaneous adipocyte growth and gene expression. This thesis speculates that there may be a factor secreted from visceral fat that influences the development of the subcutaneous fat depot. At 21d of life there was also an effect of sex, but not IUGR, on the expression of IGF mRNA in adipose tissue. Male lambs had a higher expression of IGF1 mRNA in both PAT and SAT, and a higher expression of IGF1R and IGF2R in SAT compared with female lambs. It is likely that these differences in IGF mRNA levels reflect sexual dimorphism of the GH-IGF axis. When male and female lambs were combined there was a higher expression of IGF1 mRNA in SAT compared with PAT, and a higher expression of IGF2, IGF1R and IGF2R mRNA in PAT compared with SAT. These differences in IGF mRNA expression provide a potential mechanism to explain the sex and depot specific variations in mitogenic potency of IGF1 and proliferative capacities of preadipocytes, the regional variation in adipocyte metabolism, and the difference in incidence of visceral obesity between men and women in adult life. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1347421 / Thesis (Ph.D.) - University of Adelaide, School of Molecular and Biomedical Science, 2008

Le projet de ma thèse a consisté à étudier chez les nouveau-nés la réponse des cellules épithéliales intestinales (IEC) en microARN (miR) et en peptides antimicrobiens (PAM) dans le contexte de l’infection par Cryptosporidium parvum. Ce protozoaire monoxène se développe uniquement dans les IEC et affecte plus particulièrement les nouveau-nés et les individus immunodéprimés. Nous avons étudié la réponse en miR dans les IEC après infection par C. parvum. La comparaison des réponses obtenues dans les IEC in vitro et in vivo nous a permis de montrer que l’expression du miR-181d-5p est diminuée durant l’infection et que cette diminution d’expression lèverait l’inhibition de l’expression des facteurs anti-apoptotiques OPG et BCL2, favorisant la survie du parasite dans les IEC. Nous avons également caractérisé l’impact de C. parvum sur l’expression des PAM chez le nouveau-né et leur rôle durant l’infection. Nous avons mis en évidence que l’infection entraine une forte modification de l’expression des PAM. Notre attention a été retenue par la diminution, surprenante, de l’expression de la chimiokine antimicrobienne CCL20 et de la cathélicidine CRAMP au cours de l’infection. Pour ces deux peptides, nous avons montré qu’une administration aux souriceaux réduisait significativement la charge parasitaire. Nous avons pu montrer que la protection induite par ces deux molécules antimicrobiennes résultait de leur activité parasiticide sur C. parvum. Ainsi, leur diminution d’expression semble être favorable au développement du parasite et nous avons suggéré qu’elle puisse être induite par le parasite pour échapper à cette activité parasiticide avec notamment la modulation de certains miR. / The aim of my thesis was to study in the mouse model, the intestinal epithelial cell (IEC) response during neonatal Cryptosporidium parvum infection with a focus on microRNAs (miR) and antimicrobial peptides (AMP) response. C. parvum is a protozoan parasite that affects preferentially newborn, young or immunocompromised adult and completes its life cycle only in IECs. In a first part, we studied the expression of miRs in IEC during C. parvum infection. We compared the responses between in vitro infected IEC and IECs purified from infected neonatal mice and observed a decrease of miR-181d-5p expression. This reduced expression of miR-181d-5p was associated with an upregulation of the mRNA coding for two putative targets OPG and BCL2 which are anti-apoptotic agents that may favor parasite survival in IEC. This functional relation between miR-181d-5p and OPG was next demonstrated by using reporter dual-luciferase assay. In a second part of my thesis, we characterized the AMP expression profile and studied their role during C. parvum infection in neonates. We showed that infection up-regulates a broad expression of AMP except for CCL20 and CRAMP cathelicidin for which mRNA expression was decreased. We next choose to focus our work on these two molecules and reported that administration of CCL20 and CRAMP to infected neonatal mice significantly reduced the number of parasites in the intestine through a direct killing activity on free stages of the parasite. As the decreased expression of these two AMPs during infection seems to favor the development of the parasite, this could be an escape mechanism developed by C. parvum that may occur through the modulation of miR.