OBJECTIVE: Type 2 diabetes (T2D), the most common type of diabetes characterized by high blood glucose and insulin resistance, results from both genetic and environmental factors. Our lab has proposed that chronic excess nutrients induce insulin hypersecretion from the pancreatic ß-cell, contributing to hyperinsulinemia, a prequel to T2D. Normal glucose-stimulated insulin secretion (GSIS) is oscillatory, a feature that is lost in patients with T2D. In this thesis we examine the oscillatory secretion profiles of clonal pancreatic ß-cells cultured in normal and excess nutrients that mimic conditions of T2D. We also begin to examine oscillations in protein phosphorylation that may contribute to normal ß-cell metabolism and GSIS, but if altered might potentially lead to impaired insulin secretion. METHODS: Nutrient regulation of oscillatory insulin release was studied in clonal pancreatic β-cells (INS-1) cultured in multiwell plates in both low (4 mM) and high (11 mM) glucose. Insulin secretion was stimulated in cells from multiwell plates one well at a time at 30 sec intervals and sampled simultaneously at the end of the timecourse. Insulin secretion and insulin content were measured using a homogenous time-resolved fluorescence (HTRF) insulin kit (Cisbio). Protein was extracted from these same cells for analysis of time-dependent phosphorylation by western blot using specific antibodies. Protein phosphorylation was detected using SuperSignal West Femto chemiluminescence reagent (ThermoFisher) and imaged on an iBright Imaging System (Invitrogen). RESULTS: Insulin secretion from INS-1 cells grown in separate plates and in 4 mM glucose oscillated with a period of 8.2  0.5 min compared to 5.0  0.5 min in cells cultured at 11 mM glucose. The amplitude of oscillations was 40.4  11.5 and 14.6  1.5 for cells cultured in 4 and 11 mM glucose respectively. Oscillations in secretion from cells cultured in 4 and 11 mM glucose in the same plate were not different in period but different in amplitude due in part to reduced insulin content. Oscillation in the phosphorylation patterns of acetyl-CoA carboxylase (ACC) and myristoylated alanine rich C kinase substrate (MARCKS) were measured in cells cultured in 4 mM glucose and both exhibited a peak in phosphorylation that occurred at the nadir of the insulin oscillation between peaks of insulin release. CONCLUSION: Insulin secretion from pancreatic ß-cells is affected by nutrient status as excess nutrients decrease the amplitude of oscillations in insulin release. The period of oscillations can also be affected. Oscillations in protein phosphorylation are consistent with both ACC and MARCKS contributing to normal GSIS. These initial studies provide evidence of the suitability of this model system to correlate oscillations in protein activity to exocytosis. Future studies focused on the effects of low and high glucose will potentially reveal new important therapeutic targets that may help prevent/reverse/ameliorate insulin hypersecretion leading to insulin resistance and T2D.

No description available.

(1) Adipsin is an adipokine that may link increased fat mass and adipose tissue dysfunction to obesity-related cardiometabolic diseases. Here, we investigated whether adipsin serum concentrations and adipose tissue (AT) adipsin mRNA expression are related to parameters of AT function, obesity and type 2 diabetes (T2D). (2) Methods: A cohort of 637 individuals with a wide range of age and body weight (Age: 18–85 years; BMI: 19–70 kg/m2) with (n = 237) or without (n = 400) T2D was analyzed for serum adipsin concentrations by ELISA and visceral (VAT) and subcutaneous (SAT) adipsin mRNA expression by RT-PCR. (3) Results: Adipsin serum concentrations were significantly higher in patients with T2D compared to normoglycemic individuals. We found significant positive univariate relationships of adipsin serum concentrations with age (r = 0.282, p < 0.001), body weight (r = 0.264, p < 0.001), fasting plasma glucose (r = 0.136, p = 0.006) and leptin serum concentrations (r = 0.362, p < 0.001). Neither VAT nor SAT adipsin mRNA expression correlated with adipsin serum concentrations after adjusting for age, sex and BMI. Independent of T2D status, we found significantly higher adipsin expression in SAT compared to VAT (4) Conclusions: Our data suggest that adipsin serum concentrations are strongly related to obesity and age. However, neither circulating adipsin nor adipsin AT expression reflects parameters of impaired glucose or lipid metabolism in patients with obesity with or without T2D.

L’hypertension artérielle essentielle (HTA) est une pathologie complexe, multifactorielle et à forte composante génétique. L’impact de la variabilité dans le nombre de copies sur l’HTA est encore peu connu. Nous envisagions que des variants dans le nombre de copies (CNVs) communs pourraient augmenter ou diminuer le risque pour l’HTA. Nous avons exploré cette hypothèse en réalisant des associations pangénomiques de CNVs avec l’HTA et avec l’HTA et le diabète de type 2 (DT2), chez 21 familles du Saguenay-Lac-St-Jean (SLSJ) caractérisées par un développement précoce de l’HTA et de la dyslipidémie. Pour la réplication, nous disposions, d’une part, de 3349 sujets diabétiques de la cohorte ADVANCE sélectionnés pour des complications vasculaires. D’autre part, de 187 sujets de la cohorte Tchèque Post-MONICA (CTPM), choisis selon la présence/absence d’albuminurie et/ou de syndrome métabolique. Finalement, 134 sujets de la cohorte CARTaGENE ont été analysés pour la validation fonctionnelle. Nous avons détecté deux nouveaux loci, régions de CNVs (CNVRs) à effets quantitatifs sur 17q21.31, associés à l’hypertension et au DT2 chez les sujets SLSJ et associés à l’hypertension chez les diabétiques ADVANCE. Un modèle statistique incluant les deux variants a permis de souligner le rôle essentiel du locus CNVR1 sur l’insulino-résistance, la précocité et la durée du diabète, ainsi que sur le risque cardiovasculaire. CNVR1 régule l’expression du pseudogène LOC644172 dont le dosage est associé à la prévalence de l’HTA, du DT2 et plus particulièrement au risque cardiovasculaire et à l’âge vasculaire (P<2×10-16). Nos résultats suggèrent que les porteurs de la duplication au locus CNVR1 développent précocement une anomalie de la fonction bêta pancréatique et de l’insulino-résistance, dues à un dosage élevé de LOC644172 qui perturberait, en retour, la régulation du gène paralogue fonctionnel, MAPK8IP1. Nous avons également avons identifié six CNVRs hautement hérités et associés à l'HTA chez les sujets SLSJ. Le score des effets combinés de ces CNVRs est apparu positivement et étroitement relié à la prévalence de l’HTA (P=2×10-10) et à l’âge de diagnostic de l’HTA. Dans la population SLSJ, le score des effets combinés présente une statistique C, pour l’HTA, de 0.71 et apparaît aussi performant que le score de risque Framingham pour la prédiction de l’HTA chez les moins de 25 ans. Un seul nouveau locus de CNVR sur 19q13.12, où la délétion est associée à un risque pour l’HTA, a été confirmé chez les Caucasiens CTPM. Ce CNVR englobe le gène FFAR3. Chez la souris, il a été démontré que l’action hypotensive du propionate est en partie médiée par Ffar3, à travers une interférence entre la flore intestinale et les systèmes cardiovasculaire et rénal. Les CNVRs identifiées dans cette étude, affectent des gènes ou sont localisées dans des QTLs reliés majoritairement aux réponses inflammatoires et immunitaires, au système rénal ainsi qu’aux lésions/réparations rénales ou à la spéciation. Cette étude suggère que l’étiologie de l’HTA ou de l’HTA associée au DT2 est affectée par des effets additifs ou interactifs de CNVRs. / Essential hypertension (HT) is a multifactorial complex disease with a strong genetic component. However, little is known about the effects of copy number variance on HT. We hypothesized common Copy Number Variants (CNVs) could increase or decrease the risk for HT. We performed GWAS of CNVs with HT and, with HT and Type 2 Diabetes (T2D), in 21 families of the Saguenay-Lac-St-Jean region of Quebec (FC) affected by early-onset hypertension and dyslipidemia. Replication was tested in a cohort of 3349 unrelated diabetic subjects of Caucasian origin from the ADVANCE trial. Replication was also tested in 187 individuals from the Czech Post-Monica (CPM) cross-sectional survey, ascertained by the presence/absence of albuminuria and/or metabolic syndrome. We performed locus-specific transcriptional analyses in 134 subjects from the CARTaGENE population cohort. We identified two CNV Regions (CNVRs), at 17q21.31, associated with HT and T2D in FC and associated with hypertension in ADVANCE diabetics. A statistical model of association including both CNVRs underlined the main effect size of CNVR1 on insulin resistance, T2D early onset and duration, and risk for cardiovascular diseases (CVD). CNVR1 appeared to influence LOC644172 expression, whose transcript abundance was associated with the prevalence of HT and T2D, and strongly with the risk of CVD and vascular age (P<2×10-16). Our results suggest carriers of copy-number gain at these 17q21.31 loci, principally at the CNVR1 locus, undergo premature β-cell functional deregulation and insulin resistance, due to increase dosage of the LOC644172 pseudogene, which might in turn affect the regulation of expression of its functional paralog, MAPK8IP1. We also report six different CNVR loci, highly heritable and contributing to the risk of hypertension, in French Canadians. The combined CNV risk score appeared robustly related to prevalence of hypertension (p=2×10-10) and age at diagnosis of hypertension. In FC, this combined CNV risk score model showed a C-statistic of 0.71 for HT and appeared as powerful as Framingham HT risk score in predicting hypertension in individuals aged less than 25. We validated the association of a new locus, 19q13.12 deletion-CNVR, with hypertension, in CPM. FFAR3 surrounds this 19q13.12 deletion-CNVR. It has been demonstrated that in mice, a portion of propionate hypotensive effect is mediated by Ffar3, and involves a cross-talk between the gut microbiota and the renal-cardiovascular system. The identified CNVRs appear to influence genes and QTLs mainly related to immune and inflammatory responses and renal damaged and repair. Some CNVRs are exclusive to primates. This study suggests that additive and interactive actions of multiple copy-number variants are involved in the etiology of hypertension or of hypertension associated with T2D.

Background: People with intellectual disabilities (ID) remain at high risk of developing type 2 diabetes (T2D) due to lifestyle associated risk factors such poor diets and low physical activity levels. Interventions have been adapted which target ongoing T2D self-management. However, there are no adapted programmes which prevent T2D through reducing risk factors. The present research project addresses this gap through a three-phase study on the existing literature, theoretical basis, and process evaluation of a T2D prevention programme. Methods: Phase 1: The literature reviews identified that the support needs of people with ID with T2D are currently not being met. Appropriate training needs to be delivered so that people with ID can self-manage or reduce the risk of T2D effectively. Given the early onset of T2D in people with ID and their often shorter lifespan, there is rationale for a preventative agenda in T2D education. Four potential mainstream intervention programmes were identified, and the self-efficacy model was found to be the most prevalent successfully implemented theoretical model. Phase 2: Nine sub-themes were identified following analysis of the data: 1) "Mastery through knowledge"; 2) "Mastery through tools and strategies"; 3) "Mastery through autonomy"; 4) "Influence of social setting"; 5) "Positive social comparisons"; 6) "Positive and negative self-statements"; 7) "Feedback from Caregivers"; 8) "Adjustment experiences"; 9) "Symptom awareness". These were mapped onto Bandura's (1977) Four Sources of efficacy enhancement model and were consistentwith its proposed mechanisms. The Four Sources model serves as a useful mode of enquiry for exploring people with ID's experiences and perceptions of self-managing diabetes. It also confirms the appropriateness of ssself-efficacy as a potential intervention component for this population. However, additional support may be required for people with ID to reflect meaningfully on their experiences and thus have a sense of self-efficacy. Phase3: 96% of invited students agreed to participate. The Walking Away programme was positively received, and some short-term impact was described, yet there were limitations to accessibility of the program due to the complexity of the language and materials. Suggestions for further adaptations regarding materials and content were provided, and there was perceived scope for a long-term implementation built into college curriculum. Results: Phase One: The literature reviews identified that the support needs of people with ID with T2D are currently not being met. Appropriate training needs to be delivered so that people with ID can self-manage or reduce the risk of T2D effectively. Given the early onset of T2D in people with ID and their often shorter lifespan, there is rationale for a preventative agenda in T2D education. Four potential mainstream intervention programmes were identified, and the self-efficacy model was found to be the most prevalent successfully implemented theoretical model. Phase Two: Nine sub-themes were identified following analysis of the data: 1) "Mastery through knowledge"; 2) "Mastery through tools and strategies"; 3) "Masterythrough autonomy"; 4) "Influence of social setting"; 5) "Positive social comparisons"; 6) "Positive and negative self-statements"; 7) "Feedback from Caregivers"; 8) "Adjustment experiences"; 9) "Symptom awareness". These were mapped onto Bandura's (1977) Four Sources of efficacy enhancement model and were consistent with its proposed mechanisms. The Four Sources model serves as a useful mode of enquiry for exploring people with ID's experiences and perceptions of self-managing diabetes. It also confirms the appropriateness of self-efficacy as a potential intervention component for this population. However, additional support may be required for people with ID to reflect meaningfully on their experiences and thus have a sense of self-efficacy. Phase Three: 96% of invited students agreed to participate. The Walking Away programme was positively received, and some short-term impact was described, yet there were limitations to accessibility of the program due to the complexity of the language and materials. Suggestions for further adaptations regarding materials and content were provided, and there was perceived scope for a long-term implementation built into college curriculum. Phase Three: 96% of invited students agreed to participate. The Walking Away programme was positively received, and some short-term impact was described, yet there were limitations to accessibility of the program due to the complexity of the language and materials. Suggestions for further adaptations regarding materials and content were provided, and there was perceived scope for a long-term implementation built into college curriculum. Conclusions: The findings provide basis for a further trial incorporating the suggested adaptations. A self-efficacy informed prevention programme was highly acceptability to students and teaching staff. Further education colleges provided a supportive setting and yielded a rich sample.

L’hypertension artérielle essentielle (HTA) est une pathologie complexe, multifactorielle et à forte composante génétique. L’impact de la variabilité dans le nombre de copies sur l’HTA est encore peu connu. Nous envisagions que des variants dans le nombre de copies (CNVs) communs pourraient augmenter ou diminuer le risque pour l’HTA. Nous avons exploré cette hypothèse en réalisant des associations pangénomiques de CNVs avec l’HTA et avec l’HTA et le diabète de type 2 (DT2), chez 21 familles du Saguenay-Lac-St-Jean (SLSJ) caractérisées par un développement précoce de l’HTA et de la dyslipidémie. Pour la réplication, nous disposions, d’une part, de 3349 sujets diabétiques de la cohorte ADVANCE sélectionnés pour des complications vasculaires. D’autre part, de 187 sujets de la cohorte Tchèque Post-MONICA (CTPM), choisis selon la présence/absence d’albuminurie et/ou de syndrome métabolique. Finalement, 134 sujets de la cohorte CARTaGENE ont été analysés pour la validation fonctionnelle. Nous avons détecté deux nouveaux loci, régions de CNVs (CNVRs) à effets quantitatifs sur 17q21.31, associés à l’hypertension et au DT2 chez les sujets SLSJ et associés à l’hypertension chez les diabétiques ADVANCE. Un modèle statistique incluant les deux variants a permis de souligner le rôle essentiel du locus CNVR1 sur l’insulino-résistance, la précocité et la durée du diabète, ainsi que sur le risque cardiovasculaire. CNVR1 régule l’expression du pseudogène LOC644172 dont le dosage est associé à la prévalence de l’HTA, du DT2 et plus particulièrement au risque cardiovasculaire et à l’âge vasculaire (P<2×10-16). Nos résultats suggèrent que les porteurs de la duplication au locus CNVR1 développent précocement une anomalie de la fonction bêta pancréatique et de l’insulino-résistance, dues à un dosage élevé de LOC644172 qui perturberait, en retour, la régulation du gène paralogue fonctionnel, MAPK8IP1. Nous avons également avons identifié six CNVRs hautement hérités et associés à l'HTA chez les sujets SLSJ. Le score des effets combinés de ces CNVRs est apparu positivement et étroitement relié à la prévalence de l’HTA (P=2×10-10) et à l’âge de diagnostic de l’HTA. Dans la population SLSJ, le score des effets combinés présente une statistique C, pour l’HTA, de 0.71 et apparaît aussi performant que le score de risque Framingham pour la prédiction de l’HTA chez les moins de 25 ans. Un seul nouveau locus de CNVR sur 19q13.12, où la délétion est associée à un risque pour l’HTA, a été confirmé chez les Caucasiens CTPM. Ce CNVR englobe le gène FFAR3. Chez la souris, il a été démontré que l’action hypotensive du propionate est en partie médiée par Ffar3, à travers une interférence entre la flore intestinale et les systèmes cardiovasculaire et rénal. Les CNVRs identifiées dans cette étude, affectent des gènes ou sont localisées dans des QTLs reliés majoritairement aux réponses inflammatoires et immunitaires, au système rénal ainsi qu’aux lésions/réparations rénales ou à la spéciation. Cette étude suggère que l’étiologie de l’HTA ou de l’HTA associée au DT2 est affectée par des effets additifs ou interactifs de CNVRs. / Essential hypertension (HT) is a multifactorial complex disease with a strong genetic component. However, little is known about the effects of copy number variance on HT. We hypothesized common Copy Number Variants (CNVs) could increase or decrease the risk for HT. We performed GWAS of CNVs with HT and, with HT and Type 2 Diabetes (T2D), in 21 families of the Saguenay-Lac-St-Jean region of Quebec (FC) affected by early-onset hypertension and dyslipidemia. Replication was tested in a cohort of 3349 unrelated diabetic subjects of Caucasian origin from the ADVANCE trial. Replication was also tested in 187 individuals from the Czech Post-Monica (CPM) cross-sectional survey, ascertained by the presence/absence of albuminuria and/or metabolic syndrome. We performed locus-specific transcriptional analyses in 134 subjects from the CARTaGENE population cohort. We identified two CNV Regions (CNVRs), at 17q21.31, associated with HT and T2D in FC and associated with hypertension in ADVANCE diabetics. A statistical model of association including both CNVRs underlined the main effect size of CNVR1 on insulin resistance, T2D early onset and duration, and risk for cardiovascular diseases (CVD). CNVR1 appeared to influence LOC644172 expression, whose transcript abundance was associated with the prevalence of HT and T2D, and strongly with the risk of CVD and vascular age (P<2×10-16). Our results suggest carriers of copy-number gain at these 17q21.31 loci, principally at the CNVR1 locus, undergo premature β-cell functional deregulation and insulin resistance, due to increase dosage of the LOC644172 pseudogene, which might in turn affect the regulation of expression of its functional paralog, MAPK8IP1. We also report six different CNVR loci, highly heritable and contributing to the risk of hypertension, in French Canadians. The combined CNV risk score appeared robustly related to prevalence of hypertension (p=2×10-10) and age at diagnosis of hypertension. In FC, this combined CNV risk score model showed a C-statistic of 0.71 for HT and appeared as powerful as Framingham HT risk score in predicting hypertension in individuals aged less than 25. We validated the association of a new locus, 19q13.12 deletion-CNVR, with hypertension, in CPM. FFAR3 surrounds this 19q13.12 deletion-CNVR. It has been demonstrated that in mice, a portion of propionate hypotensive effect is mediated by Ffar3, and involves a cross-talk between the gut microbiota and the renal-cardiovascular system. The identified CNVRs appear to influence genes and QTLs mainly related to immune and inflammatory responses and renal damaged and repair. Some CNVRs are exclusive to primates. This study suggests that additive and interactive actions of multiple copy-number variants are involved in the etiology of hypertension or of hypertension associated with T2D.

No description available.

Elevated serum levels of trimethylamine N-oxide (TMAO) were first associated with increased risk of cardiovascular disease (CVD) 10 years ago. Research has since defined that serum TMAO accumulation is controlled by the diet-microbiome-liver-kidney axis. Choline related nutrients are consumed in excess during over-nutrition from a Western diet. The resultant elevated serum TMAO is investigated across various chronic metabolic diseases and many tissue types. While TMAO is most clearly linked to CVD mechanisms in vascular tissue, its molecular effects on metabolic tissues are unclear. Here we report the current standing of TMAO research in metabolic disease context across relevant metabolic tissues including liver, kidney, brain, adipose, and muscle tissues. This review explores the variable TMAO effects in healthy and diseased conditions. Since impaired pancreatic β-cell function is a hallmark of metabolic disease pathogenesis which are largely unexplored in TMAO research, the following primary research results investigate TMAO effects on in vitro functional β-cell mass in relation to healthy and type 2 diabetes (T2D) conditions. Although we hypothesized that TMAO would aggravate functional β-cell mass, the data demonstrate that TMAO improves the T2D phenotype by increasing insulin secretion and production and reducing oxidative stress. Therefore, this work provides crucial support for the emerging context dependent molecular effects of TMAO during metabolic disease progression.