Renal dysfunction is a major cause of morbidity and mortality in hepatology patients. In cirrhosis, portal hypertension-related renal dysfunction evolves in parallel with advancing disease, and has important prognostic implications. Similarly, in acute liver failure, acute kidney injury is associated with increased mortality and may impact on distant organ function by driving cardiac, lung, brain, as well as liver injury. Liver transplantation is the definitive treatment for portal hypertension-related renal dysfunction in cirrhosis and acute kidney injury in acute liver failure. Yet, liver transplantation itself is complicated by both acute kidney injury and chronic kidney disease. Despite the frequency of occurrence and devastating consequences of renal dysfunction in liver disease, treatment options remain limited and there is a desperate need for advancement of scientific understanding. In this thesis I have studied 3 main aspects of renal dysfunction in liver disease. Firstly, I examined the systemic haemodynamic and renal effects of acute endothelin-1 receptor antagonism in patients with advanced portal hypertensionrelated renal dysfunction. In a randomised, double-blind, placebo controlled, crossover study of patients with refractory ascites acute combined endothelin-A and endothelin-B receptor antagonism caused a fall in glomerular filtration rate despite no change in systemic haemodynamics or total renal blood flow, and a marked reduction in urinary flow rate. These findings are consistent with a reno-protective role for endothelin-1 in portal hypertension-related renal dysfunction. Secondly, I explored the hypothesis that the acute renal dysfunction that occurs in acute liver failure is distinct from the hepatorenal syndrome of cirrhosis, and instead the systemic inflammatory response may be a critical determinant. I demonstrated that the systemic inflammatory response syndrome is associated with acute kidney injury in acute liver failure patients. Importantly, this relationship was independent of the presence of infection and of severity of liver injury. Thereafter, in patients superurgently transplanted for acute liver failure I found that, in contrast to patients undergoing elective liver transplantation, pre-transplant acute kidney injury was not associated with the development of chronic kidney disease. The results support an alternative pathophysiological process underlying the renal injury that occurs in acute liver failure. Finally, I examined the long-term decline in renal function and progression to chronic kidney disease in liver transplant recipients. I observed that patients have a clinically relevant decline in glomerular filtration rate beyond the initial post-operative period, and current focus of chronic kidney disease prevention. Mulivariate modelling identified several potentially modifiable patient factors associated with a faster rate of decline. The studies presented have helped to further our knowledge of portal hypertensionrelated renal dysfunction, acute kidney injury in acute liver failure and chronic kidney disease after liver transplantation. By doing so, we have moved one step closer to improving patient morbidity and mortality as a result of renal dysfunction in liver disease.

Inflammatory bowel disease is an incurable disease of the gastrointestinal tract of unknown aetiology. The two distinct types are Crohn's disease and ulcerative colitis. Both diseases have an imbalance of pro-and anti-inflammatory cytokines, such as interleukin-1β, interleukin-1ra and interleukin 10. Transforming growth factor beta (TGF-β) is upregulated in active disease, though upregulation also might contribute to mucosal healing and downregulation of inflammation. A treatment option which has been successfully used in Crohn's disease, alone or with corticosteroids, is nutritional therapy in the form of enteral defined formula diets, elemental or polymeric. This improves inflammatory activity as well as the nutritional status of the patient with Crohn's disease. In paediatric Crohn's disease patient's growth retardation may also be reversed. The actual mechanism by which liquid enteral diets improve inflammatory symptoms and heal the intestinal mucosal wall is not known. Hypotheses include exclusion of dietary antigens, improvement of nutritional status, alteration of bacterial flora, low lipid content and their low residue, reducing intestinal obstruction. The current study attempted to answer the question whether enteral diet and its modifications might directly influence the inflammatory response in intestinal tissue affected by inflammatory bowel disease. Intestinal endoscopic biopsies from patients with Crohn's disease, ulcerative colitis and control patients were incubated in an in-vitro organ culture model for 24 hours with elemental diet and modified enteral diets. The diets used were modified in nitrogen composition using casein or whey instead of amino acids in elemental diet. Other enteral diets were modified in fatty acid composition using fish oil, sunflower oil, safflower oil, canola oil, olive oil, fractionated coconut oil, unfractionated coconut oil and soya oil, but keeping the amino acid composition of elemental diet. The viability of tissue after 24 hours culture was established by bromodeoxyuridine uptake. Anti-and pro-inflammatory cytokines were measured in culture fluid by enzyme-linked immunoassay (ELISA) and anti-and pro-inflammatory cytokine ratios of IL1ra /IL1β and IL10/IL1β were used as a marker of in vitro inflammatory balance. In a further experiment biopsies were incubated with enteral diets containing colostrum and enteral diet containing whey extract enriched with TGF-β. Immunohistochemistry for TGF-β was performed to detect differences in TGF-V1 expression as a percentage of immunostained tissue area per mm². The results of these experiments show that enteral diets have a direct anti-inflammatory response in-vitro with an increase in anti-/pro-inflammatory cytokine ratio of IL1ra/IL1β and to some extent in IL10/IL1β. This response was different in Crohn's disease and ulcerative colitis affected tissue and was also dependent on the specific modified diet. Amino acid modified diets had an immuno-modulatory effect in Crohn's disease but not in ulcerative colitis and specific fatty acid modulated diets also produced disease and fatty acid specific response. Enteral diet modified by sunflower oil showed significant increases in the anti-/pro-inflammatory ratio in Crohn's disease and to some extent in ulcerative colitis, whereas incubation with enteral diet modified by fish oil was only anti-inflammatory in ulcerative colitis but not in Crohn's disease. The results also showed that diets containing growth factors, as in the case of colostrum and whey extract enriched with TGF-β, led to a significant upregulation in TGF-β expression in tissues affected with Crohn's disease but not with ulcerative colitis. These experiments have shown that amino acid and fatty acid modified diets can have a direct and disease specific impact on in-vitro intestinal inflammatory response in inflammatory bowel disease. Hence, by dietary modulation, it is possible to downregulate intestinal inflammatory response, and further adaptation of defined formulae diet is possible. It may also be possible to use some formulations to treat ulcerative colitis such as fish oil enriched diet, but further research into precise mechanisms of action and palatability is required.

Background: Paracetamol overdose (POD) remains a pressing clinical problem as despite the availability of a safe and effective antidote, patients continue to die or require a liver transplant. Recent evidence suggests that toxicity after POD may be more than a simple direct toxic effect as has previously been accepted and that Kupffer cells and cytokine4s such as TNF-a are involved in the pathogenesis of liver injury. Paracetamol and Hepatocyte Apoptosis Examination of liver in patients after POD revealed hepatocyte apoptosis occurring alongside striking regenerative activity. Apoptosis is important for several reasons. First, at this time paracetamol is undetectable in serum and paracetamol metabolites should be cleared from the liver, so apoptosis is not directly induced by paracetamol. Second, the rate of apoptosis represents a significant rate of cell loss from the liver. Third, the apoptosis occurs despite the background of regeneration. Paracetamol and TNF-a: Some, but not all, studies support a role for TNF-a in inducing liver injury after paracetamol overdose. In a murine model, TNF-a was elevated in serum after POD but inhibition of TNF-a action did not alter survival or liver injury. However, TNF-a augmented paracetamol toxicity in vitro by increasing rates of both apoptosis and necrosis; TNF-a also lowered the threshold for toxicity. Paradoxically, while TNF-a had no apparent effect on hepatocytes in the absence of paracetamol, pretreatment with TNF-a protected against subsequent paracetamol toxicity. Paracetamol and Kupffer Cells: Kupffer cells modulate toxic hepatic injury induced by several agents including paracetamol. Co-culture experiments comparing hepatocytes alone or in culture with Kupffer cells showed no differences in toxicity. However, production of TNF-a by macrophages was augmented by paracetamol and was further significantly elevated in co-culture with hepatocytes. The levels of TNF-a in these experiments was similar to the concentration of recombinant TNF-a which augmented paracetamol toxicity in hepatocytes alone in previous studies but in this model no difference in toxicity was noted. This finding suggests that Kupffer cells produce TNF-a in response to high doses of paracetamol, that hepatocytes behave differently in coculture than when grown alone and that the differences in response may relate to soluble factors produced by Kupffer cells. Conclusions: These studies offer new insights into mechanisms of hepatocyte death by apoptosis and regeneration in the context of drug-induced liver injury. A model is presented whereby toxin-induced activation of Kupffer cells with resulting production of cytokines modulates hepatocyte responses and alters the course of disease.

Acute Pancreatitis (AP) is inflammatory disease characterised by the pathological activation of the digestive enzymes and extensive necrosis of the pancreases and surrounding tissue, which currently has no effective treatment. Pathological agents like the bile acid taurolithocholic acid-3-sulfate (TLC-S) have been shown to induce necrosis of pancreatic acinar cells by causing intracellular calcium (Ca2+) to reach cytotoxic concentrations. TLC-S acts on elements of the secondary Ca2+ messenger pathways normally used in physiological signalling to achieve these Ca2+ increases. Nicotinic acid adenine dinucleotide phosphate (NAADP) is the most novel of these secondary Ca2+ messengers to be identified and several recent advancements have been made regarding its activity. This study has used these advancements to better characterise NAADP-induced Ca2+ release in PAC, and its role in both physiological and pathological Ca2+ signalling. NAADP-induced Ca2+ release was found to involve the activity of both Two-pore channel (TPC) and Ryanodine receptor (RyR) Ca2+ channels; with a varying involvement of the 2 TPC and 3 RyR isoforms. The NAADP antagonist Ned-19 completely inhibited Ca2+ responses to a physiological concentration of the secretagogue cholecystokinin (CCK) and had a protective effect against a pathological concentration of CCK. The size of the Ca2+ response to TLC-S was significantly inhibited in the presence of Ned-19, and the antagonist significantly reduced the amount of necrosis induced. Another related bile acid, cholate, was found to have a similar necrotic effect to PAC as a result of pathological increases in cytosolic Ca2+. While neither Ned-19 or GSK-7975A (an inhibitor of store-operated Ca2+ entry) alone had a significant effect on cholate-induced necrosis, a combination of the two did have a protective effect. These findings suggest that Ned-19 may provide a potential therapeutic solution to AP, though it may need to be used in combination with inhibitors of other Ca2+ signalling to be effective.

Smoking, excessive alcohol consumption and illicit drug use are prevalent within the Cystic Fibrosis population, with these behaviours having adverse health effects upon patients regardless of their treatment adherence. Previous quantitative research highlighting the incidence, prevalence and effects of these behaviours within the Cystic Fibrosis population demonstrates the need for more effective health promotion measures to be integrated into Cystic Fibrosis care. Therefore, attempting to reduce occurring risky health behaviours specifically within the Cystic Fibrosis population, this doctoral research aimed to identify influential factors associated with these behaviours. This research utilised qualitative methods to explore beliefs associated with risky health behaviours within the adult Cystic Fibrosis population. This first phase of data collection was followed by another qualitative study exploring Cystic Fibrosis adolescents' understanding of, and beliefs about risky health behaviours. Both phases of data collection highlight that a desire to be normal, acceptance of Cystic Fibrosis and awareness of risks are influential in initiation and engagement of risky health behaviours. Both adult and paediatric participants reported a lack of awareness regarding adverse health effects of risky behaviours, demonstrating the need for more effective health promotion and encouragement of healthier lifestyles. Accordingly, to create a corresponding intervention, the researcher has listened to how Cystic Fibrosis Specialist Nurses perceive the issue of risky health behaviours within the population, along with gaining Cystic Fibrosis health care professionals' views on what interventions are needed to reduce the occurrence of such behaviours. The researcher presently plans to collaborate with health care professionals to design an intervention, which would consist of continuous professional development for health care professionals to improve awareness on risky health behaviours within the Cystic Fibrosis population, and would inform patients regarding the Cystic Fibrosis-specific adverse effects of risky health behaviours via interdisciplinary collaboration and scholarship between psychology and technology. Overall this research has provided practical insight into policy change for the prevention and reduction of risky health behaviours within the Cystic Fibrosis population nationally and internationally by informing current advice and practice.

Obesity and fatty liver disease are characterised by an imbalance between energy intake and energy expenditure. Genetic and environmental factors strongly contribute to impaired energy homoeostasis and can trigger metabolic disorders such as hypertension, hyperglycaemia and hypercholesterolemia which are associated with type 2 diabetes, cardiovascular diseases and metabolic syndrome. The mechanisms underpinning obesity and its co-morbidity are poorly understood but dysregulation of lipid metabolism is likely to contribute and can be studied by metabolic profiling using UPLC-MS. Moreover, the host-gut axis has a strong influence on obesity and fatty liver disease development by modulation of metabolic pathways. The analytical quality of the metabolic profiling methods is critical to understand the aetiopathogenesis of obesity. Hence the aim of this PhD project is to investigate lipid metabolism in obesity and fatty liver disease. I developed and optimised a strategy for characterising the global lipid profile of plasma based on isopropanol precipitation and supplemented this with the development of a targeted assay for obtaining in depth profile of bile acids (BAs) (n=145) since BAs are known to play a specific role in obesity and fatty liver disease. Furthermore, BAs can provide insight into the role of the gut microbiota in obesity as they are metabolised by the gut microbiota. The analytical pipeline for lipid and BA analysis are subsequently applied for two human clinical studies. i) The metabolic signatures associated with subcutaneous and visceral obesity were investigated. A significant increase of LPC (16:0), unconjugated BAs and sulphated BAs with a decrease of PC (16:0/20:3), taurine conjugates was observed in visceral obesity compared to subcutaneous obesity. ii) Subtle disease progression in fatty liver disease, NAFLD and NASH was evaluated. A significant increase of triacylglycerols, hyocholic acid and tauro-conjugated BAs with a decrease of phosphocholines were observed in NASH compared to NAFLD. This phD project illustrated that metabonomic instrumentations (UPLC-MS and UPLC-MS/MS) are non-invasive and powerful analytical techniques to diagnose obesity and fatty liver disease. In addition, metabonomic analysis of urine and blood samples may offer the possibility to optimise individual diagnosis and management of patients with obesity and fatty liver disease.

Metabolic flexibility is defined as the ability of an organism to adapt from fuel oxidation to fuel availability. It is well established that obesity results in loss of metabolic flexibility, however, the exact mechanism remains unclear. Therefore, it is critical to understand the mechanism underlying metabolic flexibility to tackle the epidemic of obesity. An energy-restricted diet will lead to weight loss. However, little is known regarding the mechanisms behind the improvement in metabolic flexibility with weight loss following an energy-restricted diet. In investigation 1, I compared the effects of an energy-restricted diet and a control diet over 12 weeks on overweight and obese volunteers to elucidate the underlying mechanism of metabolic flexibility. The results demonstrated that weight loss is associated with significant reductions in body fat composition, waist circumference, hip circumference, visceral fats, blood pressure, and an improvement in postprandial insulin sensitivity. This translates into an improvement in metabolic health and metabolic flexibility. However, the underlying mechanism remained unclear. Furthermore, dietary modification using short chain fatty acids provides an attractive avenue to improve metabolic flexibility. However, the evidence for the role of short chain fatty acids in improving human metabolic flexibility is lacking. In order to investigate the effects of short chain fatty acids on metabolic flexibility, I used encapsulated sodium propionate, which is a novel method to explore its effects on glucose homeostasis. Investigation 2 consists of two parts. The first part of the study was to demonstrate the pharmacokinetic profile of encapsulated sodium propionate. The results demonstrated no significant changes in serum propionate concentrations following ingestion of encapsulated sodium propionate. The second part of the study was designed to establish the most effective dose of sodium propionate in improving glucose homeostasis. Results from this part of the study demonstrated no significant change in beta cell function.

The global obesity epidemic is a multifactorial problem associated with severe health consequences. The lifestyle behaviours of diet and physical activity are learned early, often tracking into adulthood. Identifying preventive interventions to establish children’s healthy lifestyle behaviours, in line with recommended guidelines, is a public health priority. The ‘Food Dudes’ programme is a well-evidenced behaviour change intervention, producing large and lasting increases in children’s consumption of fruit and vegetables in primary school settings. An extension of the programme, targeting physical activity, is the novel ‘Dynamic Dudes’intervention, recently trialled in primary schools. This thesis aimed to develop and evaluate a ‘Super Dynamic Food Dudes’ intervention, underpinned by the same behavioural principles as the respective primary school programmes. Chapter 1 provides a detailed literature review and identifies a paucity of such interventions. Chapter 2 modified and evaluated the Food Dudes Early Years intervention designed to increase pre-school children’s consumption of fruit and vegetables. To identify a suitable activity measurement tool, Chapter 3 validated use of the consumer-grade Fitbit Zip accelerometer to measure pre-school children’s step counts. Chapter 4 and Chapter 5 describe the development and feasibility of two physical activity components, interactive stories and in-class exercise DVDs, respectively, which were later integrated in a controlled pilot of the new physical activity intervention in Chapter 6. Drawing on outcomes and process evaluation from the preceding chapters, Chapter 7 describes and justifies further modifications to the interventions. Chapter 8 presents a controlled evaluation of the finalised two-pronged multi-component intervention in the school setting, with extension to the home. Main short-term outcomes were large and significantly greater increases in consumption of fruit and vegetables, and physical activity, in the intervention conditions, compared to the control conditions, replicating findings in primary school children. The pre-school multi-component intervention provides a promising method of preventing childhood obesity.

Inflammatory Bowel Disease (IBD) is a condition causing inflammation in the gastrointestinal tract which can be debilitating for patients, causing bowel/digestive issues and also more systemic symptoms such as fatigue and pain. IBD affects significant numbers of people and is increasing in prevalence worldwide. This thesis aimed to develop a greater understanding of patients’ experiences of living with IBD, with a particular interest in self-conscious emotions. Literature review: Pain manifestation is a common experience in IBD, yet no systematic reviews have been conducted into psychological and social factors associated with pain in this population. The current review examined 16 quantitative studies identified from searching five databases, and identified that pain correlated with quality of life (QOL), psychological distress, specific thinking and coping styles, and family responses to patient communications. However, methodological weaknesses of the included studies precluded firm conclusions from being drawn. Further investigation in this area with more robust study designs (including improved pain measurement) is recommended. Empirical study: The research study investigated experiences of self-conscious emotions in people living with IBD. Fifteen people took part in semi-structured interviews which were analysed using thematic analysis (Braun & Clarke, 2006). Two themes, each with three sub-themes, were developed to interpret participants’ experiences, which included a spectrum of self-conscious emotions including embarrassment, shame, humiliation and guilt. These are discussed from an evolutionary, relational position, with implications for clinicians working therapeutically with this population also outlined. Suggestions for additional study in this area are considered, including further investigation of the consequences of self-conscious emotions for relationships. Critical Appraisal: The critical appraisal details reflections on the research process, including learning points that the researcher intends to take forward in her career.

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