Stress incontinence (SI) is more common in white women (61%) than in black African women (27%). Previous studies have demonstrated that collagen XVII is increased and the collagen I:III ratio is decreased in continent black women compared to white suggesting better adhesiveness and elasticity in the tissue of black women. We decided to examine this concept further and analyse the elastin content in paraurethral vaginal tissue of black and white women with or without stress incontinence. A further study was set up to examine if topical oestrogen could increase elastin and change associated components of white women with pelvic organ prolapse (POP). Oestrogen treatment has been shown to increase pro-mmp2 and new collagen formation in SI women, therefore it seemed possible that such treatment could affect the collagen and elastin components of POP favourably. The clinical symptoms of POP and surgical outcome may also be improved. The first study examined the elastin content by histochemistry in paraurethral vaginal tissue while the second study assessed how locally applied oestrogen (Vagifem) given over three months influenced the mRNA expression of MMP2, elastin and collagen XVII and also elastin, collagen I and collagen III protein content of vaginal skin from women with POP. In the racial comparison study black controls showed a highly significant increase in elastin content compared with white controls (p<0.01). For SI to occur in black women a severe insult that reduces elastin production appears to be necessary as black women with SI showed significantly lower elastin content compared with black controls (p<0.05). After application of topical oestrogen to white women with POP it was shown that mRNA for MMP2 is up-regulated (p<0.01) while that for ER alpha receptor is not (p=NS). The message for collagen XVII was down-regulated (p<0.01) while collagen I and III protein were increased significantly (p<0.001 in both cases). The mRNA for elastin was significantly increased (p<0.05) after treatment but the increase in elastin protein staining did not quite reach significance. In conclusion, black women have higher elastin content in vaginal tissue compared to white and this may contribute to the lower incidence of SI in black women. Topical oestrogen over a short period has remodelling effects on key factors of the extracellular matrix of vaginal tissue. Although significant rises in elastin mRNA were shown but not protein, this treatment over longer term application could enhance some of the changes seen. This research provides evidence that black women have beneficial characteristics of vaginal skin that could resist SI and POP. Oestrogen treatment with refinements for white women could mimic black characteristics and alleviate POP symptoms.

No description available.

Coordination of uterine contractions during labour is critical for successful delivery. The mechanisms underlying this coordination are not fully understood. Propagation of contraction signals has previously been observed to occur through transmission of electrical excitation waves. This thesis aims to examine the histological microarchitecture of the muscular layer of the uterus (myometrium) and determine how this structure affects the propagation of excitation by means of in silico three-dimensional reconstruction of the myometrium and numerical simulations of a spatially structured excitation-relaxation model. A key aim of the in silico reconstruction of the smooth muscle architecture of the myometrium is to identify structural features that correspond to the control of excitation behaviour in the myometrium. This examination is aided by analysis of excitation patterns observed in multi-electrode array recordings. The reconstruction is subsequently used as a basis for simulating electrical activity in the myometrium. Novel structural features are identified here that are located at the initiation points of electrical activity and are proposed to be the pacemaker sites in rat myometrium. Furthermore, boundary of low connectivity across the mesometrial border was observed in the rat, which corresponds to the termination of excitation waves observed in multielectrode array recordings. In addition, bridges of smooth muscle cells connecting the inner and outer layers of the myometrium were observed in both rat and human myometrium. Taken together these three features suggest a novel mechanism for control of contraction in the rat myometrium; an analogous mechanism is proposed for the human myometrium. The results presented in this thesis could provide an explanation for the patterns of excitation propagation observed in human and rat uteri. Further refinements of the methods used here are outlined and expected to generate a more detailed visualisation of the structures underpinning these mechanisms.

Background: Gestational diabetes mellitus (GDM) is defined as any degree of glucose intolerance that occurs or is first recognised during pregnancy. The prevalence of GDM is 1-28% globally and 11% in China. Although GDM can cause severe maternal and neonatal outcomes, there is no consensus worldwide as to whether universal or selective screening of expectant mothers should be recommended. In 2010, The International Association of Diabetes and Pregnancy Study Groups (IADPSG) recommended that all pregnant women should be screened via a one-step universal screening approach for GDM, using a 75g oral glucose tolerance test (OGTT) with reduced thresholds. Despite ongoing debate over the efficacy and use of the IADPSG approach, China was the first country to adopt the new screening approach. A number of observational studies have shown that the new IADSPG approach is clinically more effective. However, reservations exist as to the associated increase in health costs and inconvenience to pregnant women. Aim: To assess and explore the best screening approach for GDM both globally and in China. Methods: The research involved three projects. Project I (Chapter 3) was a systematic review of the effectiveness and cost-effectiveness of universal versus selective screening for GDM, which followed a standard systematic review procedure for Diagnostic Test Accuracy studies. Project II (Chapter 4) was a Q methodology study to investigate the pregnant women’s attitudes towards and experience of the IADPSG one-step screening approach for GDM in China. A total of 30 pregnant women who visited the hospital for antenatal care in 2014 were recruited to participate in the study. The Q methodology study was undertaken using the FlashQ software and were analysed using the PQMethod software. Project III (Chapter 5) was a case-control study to establish and assess a risk score algorithm in order to improve the IADPSG approach for GDM screening in China. Medical records of 550 pregnant women (272 GDM cases and 278 controls) who had given birth in the year 2013 at the Chengdu First People’s Hospital were retrospectively collected and analysed. Univariable analysis and multiple logistic regression analysis were used to identify GDM risk factors and to formulate the risk score algorithm. A Receiver Operating Characteristic (ROC) curve was employed to assess the effectiveness of the risk score algorithm for GDM screening. Results: The systematic review (Chapter 3) included 28 effectiveness studies, four cost studies and one cost-effectiveness study. Seven out of the 28 effectiveness studies and the cost-effectiveness study favoured selective screening. The Q methodology study (Chapter 4) suggested that the participants agreed as to the importance and necessity of the IADPSG one-step GDM screening for all pregnant women. However, the non-GDM women felt somewhat burdened in undertaking the fasting and 2-hour oral Glucose Tolerance Test (OGTT) for GDM under the IADPSG approach. The participants also desired more information on GDM and OGTT both before and after the test. The case-control study (Chapter 5) identified age, height, body mass index (BMI), family history of diabetes, waist circumference, previous deliveries and blood pressure before 24th week of gestation to be risk factors for GDM in the Chinese population. Subsequently, a risk score algorithm was established, whereby the use of the risk score to select high-risk women for screening could help to exclude nearly half (45%) of non-GDM women from the OGTT while still diagnosing 80% of the GDM cases. Conclusion: Universal screening for GDM is recommended for areas where GDM prevalence is relatively high and where economic constraints circumscribing implementation of the approach do not exist. For areas where GDM prevalence is low, it is recommended that current practice, whether it is universal or selective screening, should be retained until more robust evidence emerges. The IADPSG one-step universal screening was viewed positively in terms of importance and necessity by participants of the study, and they felt that GDM screening is necessary to be undergone by every pregnant woman. At the same time, the non-GDM women also felt strongly that the two-hour OGTT requiring 3 blood samples over the test period was inconvenient and burdensome. Alternatively, the use of a risk score-based selective IADPSG approach was observed to be conducive to the exemption of nearly half (45%) of non-GDM women from the OGTT test while still diagnosing 80% of the GDM cases in China. A future validation cohort from other parts of China is required to affirm the effectiveness of this risk scoring algorithm.

Gestational diabetes mellitus (GDM), defined as glucose intolerance first identified during pregnancy, is an escalating problem worldwide which affects 5-20% of all pregnant women. It is associated with long-term consequences such as obesity, metabolic syndrome and type 2 diabetes in both the mother and affected offspring, the latter mediated in part by birthweight (“diabetes begets diabetes”). However, selective screening strategies based on established risk factors for GDM, accurately identify only around 60% of cases suggesting that there are other mechanisms involved. The aim of my thesis was to investigate the role of 2 novel biomarkers, vitamin B12 (B12) and glucagon-like peptide (GLP-1) in the development of GDM and related metabolic outcomes. A systematic review and meta-analysis showed that B12 insufficiency in pregnancy was in the order of 20-30% across the world and was associated with marginally higher, but significant, odds of low birthweight babies but these findings may be isolated to high-risk countries. In a local UK population, B12 insufficiency was independently associated with obesity, 2.6-fold higher risk of GDM and fetal macrosomia. A nationwide survey of women of child-bearing age confirmed that 12% were B12 insufficient with associated hyperhomocysteinaemia, despite apparently adequate dietary intakes of B12. This warrants urgent review of the recommended nutrient intake guidelines to optimise B12 status prior to conception. In the second part of my thesis, it was shown that overall GLP-1 response during a diagnostic glucose tolerance test is reduced in GDM women compared to controls, with a decrease in the early phase particularly predictive of post-prandial glucose levels. This potentially provides a novel mechanism to explain the delayed first phase insulin response which has been noted in GDM and T2D. Finally, to better understand how GLP-1 may exert a protective effect on the vascular complications of hyperglycaemia, a basic science project was carried out which demonstrated that liraglutide, a GLP-1 receptor agonist, enhanced the AMPK and phospho-AKT signaling pathways thereby contributing to the reduction of oxidative cell damage. In summary, this thesis supports the hypothesis there are multiple mechanisms which give rise to GDM (e.g. predominant insulin resistance or insulin secretion or combination of factors) and biomarkers such as B12 and GLP-1 can be clinically useful in identification of high-risk women. If proven in larger prospective studies, with measurements of the biomarkers from early pregnancy, these markers may be used to risk-stratify these women with the ultimate goal of reducing the transgenerational perpetuation of diabetes.

Pre-eclampsia is an important and serious condition affecting 2-8% of pregnancies worldwide and carries with it significant associated risk of morbidity and mortality for both mother and child. It is characterised by new onset hypertension after the 20th week of gestation with accompanying proteinuria. Resolution of symptoms should occur following delivery. Several pathophysiological mechanisms are common to both pre-eclampsia and cardiovascular disease, and the link between pre-eclampsia and cardiovascular disease later in life has been established. While the underlying pathophysiological mechanisms of pre-eclampsia are complex, endothelial dysfunction is a key component. Increased arterial stiffness and hypertension have also been documented. Endothelial dysfunction has been shown to extend beyond childbirth, into the postpartum period. Studies evaluating endothelial dysfunction at even longer time-points following an affected pregnancy have produced conflicting results. Results from biomarker studies have supported the concept of endothelial dysfunction throughout pregnancy and the postpartum period, but as more time elapses between index pregnancy and biomarker sampling, these results also vary. Cardiac imaging and electrocardiographic studies have also contributed to knowledge about the normal physiology of pregnancy and changes which are associated with hypertensive disorders of pregnancy during pregnancy, the postpartum period and beyond. The main focus of this thesis was to investigate the possible mechanisms behind the link between pre-eclampsia and future cardiovascular disease. The aim was to investigate women who were free from cardiovascular disease for any evidence of subclinical vascular damage long-term following a pre-eclamptic pregnancy. Overall women recruited to this study would be older than women who participated in the majority of previously published studies on this theme. Before embarking on the investigation of subclinical vascular damage in women with a history of pre-eclampsia, a link was confirmed between a history of pre-eclampsia and cardiovascular disease up to 30 years from time of index pregnancy. This was accomplished using record-linkage in a large Scottish cohort; the Generation Scotland Family Health Study (GS:SFHS). Following on from this, ECGs available in women with and without a remote history of pre-eclampsia in the GS:SFHS cohort were assessed for any obvious differences. There was a more leftward shift in the QRS-axis in these women and a trend towards a longer corrected QT interval (QTc) which approached statistical significance, but after adjusting for other co-variates, pre-eclampsia did not independently predict QTc. Investigations for subclinical vascular damage were carried out by means of non-invasive vascular function studies in women recruited from three different cohorts (blood pressure clinics, GS:SFHS and the previous Proteomics in Pre-eclampsia (PIP) study of women during pregnancy). Time since index pregnancy varied between 1-30 years. Flow-mediated dilatation (FMD) was performed to assess for endothelial dysfunction, pulse wave analysis (PWA) and pulse wave velocity (PWV) assessed arterial stiffness, and carotid ultrasound was performed to establish whether there was any evidence of atherosclerosis. After adjusting for other co-variates, I was able to demonstrate the presence of endothelial dysfunction many years after pregnancy in women with a history of pre-eclampsia in comparison with those who experienced a normotensive pregnancy. There was also a significantly higher presence of carotid plaque in women with a history of pre-eclampsia. To investigate whether the findings from the vascular study translated to findings in biomarker studies of women with a history of pre-eclampsia in comparison with controls, samples from the vascular studies cohort and from the wider GS:SFHS cohort were used. Markers of inflammation, angiogenesis, cardiac damage and collagen turnover were studied. A significantly higher vascular endothelial growth factor (VEGF) was detected in women with a history of pre-eclampsia. Pre-eclampsia is associated with an increased risk of cardiovascular disease, and endothelial dysfunction is evident later on in life. Larger studies are required to further investigate the vascular and biomarker results, and studies including more thorough cardiac assessment (such as echocardiography) in this population should also be considered. The studies described found no evidence of one single component to explain the relationship between pre-eclampsia and cardiovascular disease later in life. This is not unexpected as pre-eclampsia is a complex condition with multiple contributing factors and it is likely that the increased cardiovascular risk later in life is likewise multifactorial in origin.

Background Preterm labour and post-partum haemorrhage are leading causes of pregnancy morbidity and mortality. Previous work identified potassium channels expressed in myometrium and hypothesized modulation of channels with greater expression in MSMC than VSMC will influence contractility and avoid cardiovascular effects. By combining calcium channel blockers with potassium channel openers an enhanced tocolytic effect is anticipated. VU590 inhibits Kir 7.1 and it was hypothesised would elicit a contractile effect with therapeutic potential for post-partum haemorrhage. Aim To determine the effect of select potassium channel openers and a specific potassium channel blocker in myometrial contractility. Methods Human and murine myometrial strips were used in contractility organ bath experiments. Select combined doses were tested in myometrial small arteries using wire myography. Western blotting was carried out to determine the gestational and labour-state expression of potassium channels in human myometrium and myometrial small arteries. Results Pinacidil demonstrated a relaxatory effect on both myometrial and vascular smooth muscle. Riluzole reduced contractility alone and greater inhibition in combination with nifedipine than nifedipine alone. Riluzole appeared to have a mild effect on myometrial arteries. Kir 7.1 showed a trend of diminished expression by gestation and was downregulated in term and preterm labour states. VU590 elicited a significant increase contractility characterised by a prolonged contraction phase of up to 6.7±1.9 hrs (VU590 10 µM). A gestational-dependent effect was seen on murine myometrium. Conclusion The combination of nifedipine with potassium channel openers has a more potent effect on reducing contractility than either compound alone. Riluzole combined with nifedipine warrants further investigation for potential tocolytic therapy. VU590 augments spontaneous contractions profoundly in human myometrium in vitro and could have potential therapeutic benefits in the treatment of postpartum haemorrhage.

No description available.

No description available.

No description available.