Acyl-ghrelin mediated lipid retention and inflammation within in vitro and ex vivo adipose depots

The 28 amino acid hormone, ghrelin, has been found to have various effects on metabolism. This thesis focuses on the pathways integrated into ghrelin’s effect within adipocytes and adipose tissue depots of those with and without Type 2 diabetes. To determine whether acyl-ghrelin plays a role in mediating the metabolic state in an in vitro and ex vivo setting this thesis investigates cellular mechanisms via the analysis of: lipid staining, lipid retention gene expression pathway, inflammatory marker levels and determination of oxidative burden. This project confirms and translates previous murine model findings that establishes a mediatory role for acyl-ghrelin within lipid retention. Furthermore, this mechanism is influenced and magnified within the presence of hyperglycaemia, indicating that the impact of glucose metabolism on acyl-ghrelin and lipid homeostasis may result in the deterioration of dyslipidaemia. In addition to novel findings relating to lipid retention, results indicate that acyl-ghrelin also impacts the inflammatory state. Acyl-ghrelin exposure resulted in a marked decrease in pro-inflammatory marker IL-6, and ghrelin mRNA expression was associated with an increase in IL-10 and total antioxidant status. The promotion of the inflammatory state in the presence of acyl-ghrelin may yield novel therapeutic avenues for acyl-ghrelin combination treatment in the amelioration of the low-grade inflammation present within Type 2 diabetes

Interrupting prolonged sitting with frequent short bouts of light‐intensity activity in people with type 1 diabetes improves glycaemic control without increasing hypoglycaemia: The <scp>SIT‐LESS</scp> randomised controlled trial

AimTo examine the impact of interrupting prolonged sitting with frequent short bouts of light-intensity activity on glycaemic control in people with type 1 diabetes (T1D).Materials and MethodsIn total, 32 inactive adults with T1D [aged 27.9 ± 4.7 years, 15 men, diabetes duration 16.0 ± 6.9 years and glycated haemoglobin 8.4 ± 1.4% (68 ± 2.3 mmol/mol)] underwent two 7-h experimental conditions in a randomised crossover fashion with >7-day washout consisting of: uninterrupted sitting (SIT), or, interrupted sitting with 3-min bouts of self-paced walking at 30-min intervals (SIT-LESS). Standardised mixed-macronutrient meals were administered 3.5 h apart during each condition. Blinded continuous glucose monitoring captured interstitial glucose responses during the 7-h experimental period and for a further 48-h under free-living conditions.ResultsSIT-LESS reduced total mean glucose (SIT 8.2 ± 2.6 vs. SIT-LESS 6.9 ± 1.7 mmol/L, p = .001) and increased time in range (3.9-10.0 mmol/L) by 13.7% (SIT 71.5 ± 9.5 vs. SIT-LESS 85.1 ± 7.1%, p = .002). Hyperglycaemia (>10.0 mmol/L) was reduced by 15.0% under SIT-LESS (SIT 24.2 ± 10.8 vs. SIT-LESS 9.2 ± 6.4%, p = .002), whereas hypoglycaemia exposure (<3.9 mmol/L) (SIT 4.6 ± 3.0 vs. SIT-LESS 6.0 ± 6.0%, p = .583) was comparable across conditions. SIT-LESS reduced glycaemic variability (coefficient of variation %) by 7.8% across the observation window (p = .021). These findings were consistent when assessing discrete time periods, with SIT-LESS improving experimental and free-living postprandial, whole-day and night-time glycaemic outcomes (p < .05).ConclusionsInterrupting prolonged sitting with frequent short bouts of light-intensity activity improves acute postprandial and 48-h glycaemia in adults with T1D. This pragmatic strategy is an efficacious approach to reducing sedentariness and increasing physical activity levels without increasing risk of hypoglycaemia in T1D

Anti-carcinogenic effects of exercise-conditioned human serum: evidence, relevance and opportunities

Regular physical activity reduces the risk of several site-specific cancers in humans and suppresses tumour growth in animal models. The mechanisms through which exercise reduces tumour growth remain incompletely understood, but an intriguing and accumulating body of evidence suggests that the incubation of cancer cells with post-exercise serum can have powerful effects on key hallmarks of cancer cell behaviour in vitro. This suggests that exercise can impact tumour biology through direct changes in circulating proteins, RNA molecules and metabolites. Here, we provide a comprehensive narrative overview of what is known about the effects of exercise-conditioned sera on in vitro cancer cell behaviour. In doing so, we consider the key limitations of the current body of literature, both from the perspective of exercise physiology and cancer biology, and we discuss the potential in vivo physiological relevance of these findings. We propose key opportunities for future research in an area that has the potential to identify key anti-oncogenic protein targets and optimise physical activity recommendations for cancer prevention, treatment and survivorship

The -765G>C Cyclooxygenase-2 Promoter Polymorphism is associated with Type 2 Diabetes Mellitus, Low High-density Lipoprotein and Manifest Angina

Background & Aims: Cycloxygenase-2 (COX-2) catalyses the rate limiting step of prostaglandin biosynthesis. Despite previous studies, it is still unclear whether COX-2 is beneficial or detrimental to cardiovascular risk. The aim of this study was to examine the -765G>C (rs20417) PTGS2 promoter gene variant, which encodes COX-2, in relation to markers of cardiovascular risk in a sample of well-characterised subjects with diabetes mellitus. Methods & Results: We observed that the CC genotype was more prevalent in Type 2 diabetes mellitus compared to Type 1 (84.2 vs 15.8%; p≤0.05), and was significantly associated with clinically manifest angina (GG vs GC vs CC: 14.3% vs 15.6% vs 28.0%; p=0.009) and lower HDL-cholesterol levels (GG vs GC vs CC: 1.3mmol/L vs 1.4mmol/L vs 1.2mmol/L; p=0.032). This is in line with previous studies showing that -765G>C genotype variant alters Sp1 binding, resulting in decreased COX-2 activity which is associated with atherosclerosis. Conclusion: We conclude that the CC genotype may contribute to a reduction of prostaglandin E2 mediated insulin secretion, predisposing those individuals to Type 2 diabetes mellitus. Further prospective work is warranted in order to examine the association between COX-2 and cardiovascular risk

Temporal Effects of Sleeve Gastrectomy on Glucose-Insulin Homeostasis and Incretin Hormone Response at 1 and 6 Months

BackgroundBariatric surgery is an effective treatment for morbid obesity and glycaemic dysfunction.ObjectivesThe aim of the work was to examine both the static and dynamic changes of glucose-insulin homeostasis and incretin hormone response following sleeve gastrectomy (SG) in a sample of 55 participants preoperatively and 1 month and 6 months postoperatively. The focus was on a sample of patients with impaired glucose tolerance and type 2 diabetes (T2D).SettingMorriston Hospital, UK.MethodsProspective study comprising of 55 participants with impaired glucose homeostasis and T2D undergoing SG (mean body mass index [BMI] 50.4 kg/m2, mean glycated haemoglobin [A1C] 7.4%). Serial measurements of glucose, insulin, C-peptide, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic hormone (GIP) were performed during oral glucose tolerance testing preoperatively and 1 and 6 months postoperatively. Areas under the curve (AUC) were examined at 30, 60, and 120 min.ResultsWe observed significant improvements in measures of obesity, as well as static and dynamic measures of glucose, insulin, C-peptide and HOMA. Furthermore, significant increases in GLP-1 response as early as 6 months postoperatively were also seen.ConclusionsTo our knowledge, no study has examined the detailed dynamic changes in glucose and insulin homeostasis in this number of participants undergoing SG in relation to incretin hormones GIP and GLP-1. This current study supports the role of SG for the treatment of obesity-related glucose dysregulation

Passing on the exercise baton: What can endocrine patients learn from elite athletes?

As elite athletes demonstrate through the Olympic motto ‘citius, altius, fortius’, new performance records are driven forward by favourable skeletal muscle bioenergetics, cardiorespiratory, and endocrine system adaptations. At a recreational level, regular physical activity is an effective non-pharmacological therapy in the treatment of many endocrine conditions. However, the impact of physical exercise on endocrine function and how best to incorporate exercise therapy into clinical care are not well understood. Beyond the pursuit of an Olympic medal, elite athletes may therefore serve as role models for showcasing how exercise can help in the management of endocrine disorders and improve metabolic dysfunction.This review summarises research evidence for clinicians who wish to understand endocrine changes in athletes who already perform high levels of activity as well as to encourage patients to exercise more safely. Herein, we detail the upper limits of athleticism to showcase the adaptability of human endocrine-metabolic-physiological systems. Then, we describe the growing research base that advocates the importance of understanding maladaptation to physical training and nutrition in males and females; especially the young. Finally, we explore the impact of physical activity in improving some endocrine disorders with guidance on how lessons can be taken from athletes training and incorporated into strategies to move more people more often

Development and characterization of an in vitro system of the human retina using cultured cell lines

Background: Previously developed in vitro cultures of the human retina have been solo or dual cell cultures. We developed a triple-cell culture in vitro model utilizing a membrane system to produce a better representation of a functional and morphological human retina. Methods: Retinal microvascular endothelial cells (HRMVEC/ACBRI181, Cell systems), retinal pigment epithelium cells (RPE/ARPE-19, ATCC) and Müller glial cells (MIO-M1, UCL) were grown in a triple-culture. Our optimized triple-culture media contained a mix of specific endothelial medium and high glucose Dulbecco's Modified Eagle's medium (DMEM), where all three layers were viable for up to 5 days. Co-culture effect on morphological changes (cell staining) and gene expression of functional genes (pigment epithelial derived factor (PEDF) and vascular endothelial growth factor (VEGF)) were measured from RNA via real time PCR. Expression of tight junction protein 1 (TJP1) was measured in RNA isolated from ARPE-19s, to assess barrier stability. Results: The triple-culture promotes certain cell functionality through up-regulation of TJP1, increasing PEDF and decreasing VEGF expression highlighting its importance for the assessment of disease mechanisms distinct from a solo culture which would not allow the true effect of the native microenvironment to be elucidated. Conclusion: This model's novelty and reliability allows for the assessment of singular cellular function within the retinal microenvironment and overall assessment of retinal health, whilst eliminating the requirement of animal-based models

Acyl-ghrelin mediated lipid retention and inflammation in obesity-related Type 2 diabetes

Acyl-ghrelin has various peripheral effects including the potential role in mediating cellular lipid removal and macrophage polarization. Previous reports are contradictory as to how glycaemia and acyl-ghrelin mediates lipid retention and inflammation within individuals with Type 2 diabetes (T2D). Our aim was to explore acyl-ghrelin levels and ghrelin expression in relation to lipid and inflammatory markers within an ex vivo human model, biopsied visceral adipose tissue.Results indicated that acyl-ghrelin was associated with a decline in key lipid homeostasis genes ABCG1 and LXRβ expression. Within T2D there was also a down regulation of these genes which was independent of acyl-ghrelin levels. Circulatory pro-inflammatory markers (IL-6 and TNFα) had no association with ghrelin expression nor circulating acyl-ghrelin levels. Anti-inflammatory marker (IL-10) and total antioxidant status (TAOS%) were positively associated with ghrelin expression across samples from all groups combined (total sample cohort) and specifically within the obesity sample cohorts.Data supported the hypothesis that hyperglycaemia and acyl-ghrelin have a regulatory role in lipid retention. Furthermore, that both acyl- and desacyl-ghrelin is responsible for a protective inflammatory response; however this response is diminished in T2D