京都大学 / 0048 / 新制・論文博士 / 博士(医学) / 乙第13069号 / 論医博第2124号 / 新制||医||1019(附属図書館) / 33220 / 京都大学大学院医学研究科医学専攻 / (主査)教授 小川 修, 教授 篠原 隆司, 教授 斎藤 通紀 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM

Call number: LD2668 .T4 1938 B42

Our limited understanding of the molecular mechanisms driving the onset of normal human parturition makes it difficult to identify ‘what goes wrong’ in conditions such as preterm labour (PTL), preterm prelabour rupture of membranes (PPROM) and postpartum haemorrhage (PPH). This incomplete understanding seriously hampers the development of effective ways to predict, prevent and treat parturition complications, which are a cause of significant neonatal and maternal morbidity. Two principal barriers to improving our understanding are 1) the great complexity of both the molecular interactions initiating parturition and the aetiology of parturition complications, and 2) the difficulty in generating relevant high quality molecular and epidemiological data. To help make sense of this complexity, data should be analysed comprehensively to maximise the amount of useful information gleaned from it. This thesis aimed to explore the use of specialist methods to analyse novel and previously published data to study the molecular mechanisms initiating human parturition and the epidemiology of parturition complications. The molecular mechanisms initiating parturition were explored through a gene expression microarray of labouring and non-labouring myometrial tissue. This is the largest microarray of its kind to date. Functional analysis and a network graph approach were used to reveal genes and molecular pathways associated with labour. The first ever meta-analysis of similar myometrial microarray datasets was also conducted to assess the reliability and generalisability of the results. This work supported the hypothesis that labour is associated with inflammatory events in the myometrium. A computer model of an inflammatory signalling pathway associated with infection-induced PTL was then built to provide proof of concept that such models can be used to study parturition. The model was based on published data and described lipopolysaccharide-induced activation of the transcription factor Nuclear Factor kappa B (NF-κB). This is the first attempt to generate a dynamic kinetic model that has relevance to the molecular mechanisms of PTL, and the first model of this pathway to explicitly include molecular interactions upstream of NF-κB activation. The epidemiology of complications at parturition was explored using three methods. Firstly, a novel approach was developed to use network graphs to visualise and analyse a dataset of nearly 50,000 birth records. The approach provided a quick and effective way to preliminarily explore relationships between exposures and pregnancy outcomes in an unbiased data-driven manner. Secondly, a record-linkage study of two datasets of birth records was conducted to determine risk factors for PPH, including intergenerational transmission of risk. This confirmed several known risk factors of PPH and showed that women whose mothers or grandmothers had PPH do not appear to be at increased risk themselves. Finally, a systematic review and meta-analysis of three randomised controlled trials investigated the effectiveness of fetal assessment methods in improving maternal and neonatal outcomes following PPROM. The review concluded that there is currently insufficient evidence on the benefits and harms of any method of fetal assessment, and further randomised controlled trials are required.

published_or_final_version / abstract / Obstetrics and Gynaecology / Master / Master of Philosophy

In mammals, development of a new organism requires fertilisation of the female egg by sperm. The resulting zygote develops into the blastocyst stage as it travels towards the uterus. Within the uterus, the blastocyst invades the maternal tissues and establishes access to the maternal blood supply. This process is called implantation and is absolutely essential for the further development of the conceptus and establishment of pregnancy. Successful implantation requires a proper preparation of the uterus and the embryo as well as a molecular dialogue between the embryo and the uterine tissues. Female mice that have a disruption in the Plcβ1 gene are infertile. In the course of this Thesis it became apparent that the main cause of their infertility is their inability to implant their embryos. PLCβ1 protein is a mediator of G-protein coupled receptor (GPCR) signalling and it is involved in the production of second messengers essential for downstream transmission of signals. A host of reproductive functions are under the control of GPCR signalling. In this PhD Thesis the infertile phenotype of Plcβ1 knockout (KO) female mice was investigated to identify the reproductive processes affected by the lack of a functional PLCβ1 protein. A combination of histological, molecular biology and in vivo techniques were utilised to show that at the time of implantation, embryos fail to attach to the uterine epithelium of KO uteri. In addition, it was demonstrated that estrogen signalling and components of the endocannabinoid metabolism, both key processes for successful implantation are severely altered in KO uteri. These observations show that KO uteri fail to prepare for implantation. In addition, the KO reproductive tract exerts a detrimental effect on pre- and peri- implantation embryo development. Currently, failure of implantation is thought to be one of the major causes of infertility in women and up to this date there are no successful treatments. The results of this project expand our current knowledge on the physiology of implantation and provide cues for the development of diagnostic markers and treatments for the women who are unable to conceive.

Ovarian hyperstimulation is achieved through ovarian gonadotropin stimulation, and thus associated with supraphysiological levels of oestrogen and progesterone. To investigate the effects of exogenous gonadotropins on the expression of TGF b1 and TGF b2, which have been recognized as possible modulators of many endometrial functions, FSH and hCG were superimposed upon the normal hormonal milieu of the cycling rat, prior to mating. Endometrial tissue was collected at 4.5, 5.5 and 6.5 days after mating. ELISA was performed to estimate blood oestrogen and progesterone levels and immunohistochemistry was undertaken to localize TGF b1 and TGF b2 in the uterine endometrium. Apart from the known detrimental effects of hyperstimulation on gross morphology, hormone levels and endometrial histology, the hyperstimulation was also found to affect TGF b expression. An increase in the expression of TGF b2 was distinct in the glandular epithelium of the hyperstimulated animals, while regionalized expression of both TGF b1 and TGF b2 was prominent in the stroma. In conclusion, hyperstimulation affects the expression of both TGF b1 and TGF b2, which may contribute to the disruption of the endometrial environment required for successful embryo implantation.

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Die vorliegende Arbeit stellt die Powerdopplersonographie an Hand von Vergleichen und Gegenüberstellungen in deskriptiver Weise als nicht invasive Methode vor. Insgesamt wurden bei sechs klinisch-gynäkologisch gesunden Warmblutstuten 16 abgeschlossene, spontane und regelmäßige Zyklen mittels transrektalem Ultraschall aufgezeichnet. Es wurden 10590 dopplersonographische Messdaten ausgewertet, hinzu kamen 9601 powerdopplersonographische Bilddateien, die mittels Pixelanalysesoftware ANALYSIS PRO 1.1 analysiert wurden.