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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
831

Le rôle de Gas6 dans le métabolisme du glucose

Germain, Amélie 01 1900 (has links)
Gas6 est une protéine sécrétée gamma-carboxylée de façon dépendante à la vitamine K et fonctionne comme un ligand pour les récepteurs tyrosine kinase de la famille TAM : TYRO3, AXL et MERTK. Plusieurs études chez l’humain suggèrent un rôle potentiel de Gas6 dans la résistance à l’insuline et l’obésité. Cependant, le mécanisme par lequel Gas6 influence la sensibilité à l’insuline est toujours inconnu. Selon nos résultats préliminaires, nous avons posé l’hypothèse que GAS6 régule la sensibilité à l’insuline dans le muscle et le tissu adipeux via son interaction avec ses récepteurs à la surface des cellules. Méthodes et résultats : Nous avons observé qu’Axl est le récepteur de Gas6 le plus exprimé dans les adipocytes et les myocytes. De plus, nous avons déterminé qu’AXL et sa cible AKT sont phosphorylés dans les C2C12 différenciées suivant une stimulation avec la protéine Gas6 recombinante. Également, ces événements de phosphorylation sont inhibés par la molécule LDC1267, un inhibiteur des récepteurs TAM. Ensuite, les souris Gas6-/- montrent une augmentation de la tolérance au glucose et de la sensibilité à l’insuline. En contraste, les souris transgéniques surexprimant Gas6 présentent une résistance à l’insuline en comparaison avec les souris de type sauvages. Pour investiguer en profondeur les événements moléculaires en aval de Gas6 et ses récepteurs, nous avons caractérisé le transcriptome dépendant de la signalisation Gas6-récepteurs TAM dans les myotubes en utilisant une expérience de séquençage d’ARN. De façon intéressante, nous avons identifié que plusieurs molécules cibles de la signalisation de l’insuline sont modifiées par Gas6. Ensemble, ces résultats supportent la notion que Gas6 est impliqué dans la régulation de la sensibilité à l’insuline in vivo. Cette fonction se produit lors de son interaction avec au moins un de ses récepteurs, soit Axl, à la surface des myotubes. / Introduction: Gas6 is a secreted protein which is gamma-carboxylated in a vitamin K dependent manner and functions as ligand for the TAM family of receptor tyrosine kinases: TYRO3, AXL and MERTK. A few studies in humans suggest a potential role for Gas6 in insulin resistance and obesity. Nevertheless, the mechanisms by which Gas6 influences insulin resistance remain unknown. Based on our preliminary data, we hypothesized that Gas6 regulates insulin sensitivity in muscle and adipose tissue through its interaction with its receptors. Methods and Results: We observed that Axl is the most highly expressed Gas6 receptor in adipocytes and myocytes. Moreover, we found that Axl and its downstream target AKT are phosphorylated in C2C12 myotubes following stimulation with recombinant Gas6. Importantly, these phosphorylation events are abrogated when cells where pre-treated with LDC1267, a TAM pharmacological inhibitors. In addition, Gas6-/- mice display an improved glucose tolerance, associated with increased insulin sensitivity when compared to wild-type mice. In contrast, Gas6 transgenic mice characterized by increased circulating Gas6 levels (ApoE-Gas6 Tg) have reduced insulin sensitivity. To further investigate the molecular events downstream of Gas6 and of its receptor in muscle cells, we characterized the Gas6/Axl-dependent transcriptome in myotubes using RNAseq. Interestingly, we found that key regulators of the insulin signaling pathway were modulated by Gas6 and Axl. Conclusion and Relevance: Together, these results support the notion that Gas6 is implicated in the regulation of insulin sensitivity in vivo. This function of Gas6 occurs through its interaction with Axl at the surface of myocytes.
832

Améliorer la pharmacocinétique de l’insuline analogue ultrarapide chez des sujets obèses et diabétiques de type 2 / Improve the pharmacokinetic of short-acting insulin analogue in obese subject with type 2 diabetes

Gagnon-Auger, Maude January 2015 (has links)
Résumé: Comparées aux classiques insulines humaines régulières (IHR), les insulines analogues ultrarapides (IAUR) ont été conçues pour mieux synchroniser le pic insulinémique avec l’absorption du repas. Le progrès a été démontré chez les patients diabétiques de type 1, mais le contrôle glycémique s’est peu ou pas amélioré chez les patients diabétiques de type 2 (DT2), qu’ils soient sous IAUR ou IHR. Or ces patients constituent 75 % des utilisateurs d’insuline. L’utilité des IAUR est donc toujours débattue. La dose (donc le volume) injectée et le flot sanguin dans le tissu adipeux sous-cutané (FSTA) sont les facteurs majeurs de l’absorption de l’insuline. Les patients DT2, résistants à l’insuline, s’injectent des doses importantes et leur FSTA est de 50 à 70 % plus faible que celui des sujets sains de poids normal (PN). Nous avons montré que l’absorption sous-cutanée des IAUR est diminuée chez les sujets obèses et DT2 (ODT2) par rapport aux sujets PN, que le volume injecté avait un effet délétère additionnel et que le FSTA peut être augmenté de façon pharmacologique avec un agent vasoactif (AV) chez des sujets résistants à l’insuline. Nous suggérons que l’ajout d’un AV à une IAUR va augmenter le FSTA au site d’injection et donc améliorer sa pharmacocinétique (PK) et sa pharmacodynamie (PD). Pour vérifier cette hypothèse, nous avons 1) évalué la réponse du FSTA à 4 AV chez des sujets PN, obèses non-diabétiques et ODT2; 2) évalué la PK/PD et la biodisponibilité de l’IAUR lispro ± AV chez des sujets ODT2; et 3) caractérisé l’expression des cibles des AV dans le tissu adipeux sous-cutané chez les sujets énumérés en 1). Les 4 AV ont augmenté le FSTA des sujets ODT2, mais moins que celui des autres sujets. L’occurrence de la raréfaction et/ou dysfonction microvasculaire chez les sujets ODT2 pourrait expliquer l’hyporéactivité vasculaire aux AV testés. Le plus actif des AV chez les sujets ODT2 a été ajouté à l’IAUR lispro pour améliorer sont absorption sc. Les PK/PD ont été améliorées seulement chez les sujets ODT2 avec une hémoglobine glycosylée A1c ≥ 8 %; c’est-à-dire 4 sujets sur 8. Chez ces derniers, l’absorption de 30 U + AV a été plus rapide de 14 et 71 min à 20 et 80 % de l’aire sous la courbe totale de la lispro plasmatique, respectivement. Chez les 4 autres sujets ODT2, l’absorption de la lispro semble s’être détériorée avec l’AV. Une interaction chimique a peut-être eu lieu entre l’AV et la lispro, ce qui aurait perturbé son absorption. Selon nos résultats, le niveau de contrôle du diabète, le volume d’injection et les caractéristiques chimiques de l’AV seraient des modulateurs de l’efficacité du concept IAUR + AV. Il nous faut maintenant déterminer l’impact de ces facteurs sur la capacité d’un AV à améliorer l’absorption sc de l’IAUR chez les sujets ODT2. / Abstract: Compared to classic regular human insulin (RHI), short-acting insulin analogues were designed to better synchronize plasma insulin increase to food absorption. Although improvements were noted in subjects with type 1 diabetes, slight to no improvement in glycemic control were observed in subjects with type 2 diabetes (T2D) using SAIA instead of RHI. Nevertheless, they represent 75 % of all insulin users. Consequently, the relative useful-ness of SAIA in T2D patients is currently hotly debated. Injected volume and subcutaneous (sc) adipose tissue blood flow (ATBF) are two main factors involved in insulin absorption. In fact, T2D patients use large doses of insulin because of their resistance to insulin and have an ATBF 50 to 70 % lower than lean healthy subjects. We already showed that SAIA absorption is decreased in obese T2D (OT2D) subjects compared to normal weight healthy subjects and that volume has additional detrimental effects. We also showed that ATBF can be increased pharmacologically with vasoactive agents (VA) in healthy and insulin-resistant subjects. Then we suggest that in OT2D subjects, addition of VA to SAIA preparations will locally increase ATBF, improve insulin sc absorption (Pharmacokinetic - PK) and bioavailability, thus insulin hypoglycemic effect (Pharmacodynamic - PD). To test this hypothesis, we 1) assessed ATBF response of 4 selected VA within three experimental groups (normal weight, obese non-diabetic and OT2D subjects); 2) evaluated insulin PK/PD and bioavailability improvement in OT2D subjects after the addition of the best VA to SAIA lispro and 3) characterized expression of selected VA targets in sc adipose tissue biopsies, within equivalent experimental groups, and compared results with ATBF responses. All 4 VA were able to increase ATBF of OT2D subjects but in a less extend than other subjects. The occurrence of microvascular rarefaction and/or dysfunction in OT2D subjects can explain the hyporeactivity to tested VA. Nevertheless, one VA among others was shown more effective to increase ATBF in OT2D subjects and was then tested (mixed) with SAIA lispro. With the AV, PK/PD were improved only in OT2D subjects with A1c glycated hemoglobin ≥ 8 %; 4 subjects on 8. The sc absorption of 30 U + VA was faster by 14 and 71 min for respectively 20 and 80 % of the total area under the lispro plasmatic curve. But the sc absorption with VA appeared blunted with the other subjects. Maybe detrimental chemical interactions occurred between the VA and lispro, which could impede absorption. Our results suggest that diabetes control state, injection volume, and VA chemical characteristics influence the efficacy of our SAIA + VA concept. Further tests are needed to seize the impact of these factors on VA effectiveness in sc absorption improvement of SAIA in OT2D subjects.
833

The relationship among serum levels of manganese superoxide dismutase and mtDNA 8-hydroxy-2'-deoxyguanosine, and dietary antioxidants intake in Type 2 Diabetes

MCLEAN, MICHAEL ANDREW 03 October 2014 (has links)
Oxidative stress plays a key role in the development of Type 2 Diabetes (T2D). This cross-sectional study examined the relationship among serum levels of manganese superoxide dismutase (MnSOD), 8-hydroxy-2’-deoxyguanosine (8OHdG), dietary antioxidant intakes and glycemic control in African Americans (n=209) and Haitian Americans (n=234) with and without T2D. African Americans had higher BMI (32.8 vs. 29.3 kg/m2), higher energy intake (2148 vs. 1770 kcal), and were more educated as compared to Haitian Americans; all variables were significant at p < .001. Serum levels of 8OHdG and MnSOD for African Americans (1691.0 ± 225.1 pg/ml, 2538.0 ± 1091.8 pg/ml; respectively) were significantly higher than for Haitian Americans (1626.2 ± 222.9, 2015.8 ± 656.3 pg/ml; respectively). 8OHdG was negatively correlated with MnSOD (r = -.167, p < .001) in T2D. Having T2D was negatively correlated with MnSOD (r = -.337; p < .01) and positively correlated with 8OHdG (r = .500; p < .01). African Americans and Haitian Americans with T2D had fasting plasma glucose (FPG) levels of 143.0 ± 61.0 mg/dl and 157.6 ± 65.5 mg/dl, and A1C of 7.5 ± 1.8 % and 8.4 ± 2.4 %, respectively. African Americans and Haitian Americans without T2D had FPG levels of 95.8 ± 13.2 mg/dl and 98.7 ± 16.9 mg/dl, and A1C of 5.9 ± 0.4% and 6.0 ± 0.5%, respectively. Dietary intakes of vitamin C and vitamin D were negatively correlated with FPG (r = -.21; r = -.19, p < .05) respectively. Carotenoids negatively correlated with A1C (r = -.19, p < .05). Lower levels of MnSOD were associated with lower levels of zinc, r = .10, p < .05, and higher levels of carotenoids r = -.10, p < .05. Higher levels of 8OHdG were associated with lower levels of Vitamin D, r = -.14, p < .01, and carotenoids, r = -.09, p < .05. The results demonstrate greater oxidative mtDNA damage in persons with T2D compared to those without T2D and in African Americans compared with Haitian Americans. The inverse relationship between dietary intake of antioxidants and oxidative stress implies a potential to reduce oxidative stress with diet. African Americans were significantly younger (53.3 vs. 55.6 years), had higher BMI (32.8 vs. 29.3 kg/m2), higher energy intake (2148 vs. 1770 kcal), and were more educated as compared to Haitian Americans; all variables were significant at p < .001. Serum levels of 8OHdG and MnSOD for African Americans (1691.0 ± 225.1 pg/ml, 2538.0 ± 1091.8 pg/ml; respectively) were significantly higher than for Haitian Americans (1626.2 ± 222.9, 2015.8 ± 656.3 pg/ml; respectively). 8OHdG was negatively correlated with MnSOD (r = -.167, p < .001) in T2D. Having T2D was negatively correlated with MnSOD (r = -.337; p < .01) and positively correlated with 8OHdG (r = .500; p < .01). African Americans and Haitian Americans with T2D had fasting plasma glucose (FPG) levels of 143.0 ± 61.0 mg/dl and 157.6 ± 65.5 mg/dl, and A1C of 7.5 ± 1.8 % and 8.4 ± 2.4 %, respectively. African Americans and Haitian Americans without T2D had FPG levels of 95.8 ± 13.2 mg/dl and 98.7 ± 16.9 mg/dl, and A1C of 5.9 ± 0.4% and 6.0 ± 0.5%, respectively. Dietary intakes of vitamin C and vitamin D were negatively correlated with FPG (r = -.21; r = -.19, p < .05) respectively. Carotenoids negatively correlated with A1C (r = -.19, p < .05). Lower levels of MnSOD were associated with lower levels of zinc, r = .10, p < .05, and higher levels of carotenoids r = -.10, p < .05. Higher levels of 8OHdG were associated with lower levels of Vitamin D, r = -.14, p < .01, and carotenoids, r = -.09, p < .05. The results demonstrate greater oxidative mtDNA damage in persons with T2D compared to those without T2D and in African Americans compared with Haitian Americans. The inverse relationship between dietary intake of antioxidants and oxidative stress implies a potential to reduce oxidative stress with diet.
834

Effects of Selected Natural Health Products on Drug Metabolism: Implications for Pharmacovigilance

Liu, Rui January 2011 (has links)
Seventeen Cree anti-diabetic herbal medicines and eight Traditional Chinese Medicines have been examined for their potential to cause interactions with drugs, which is considered as a major reason for adverse drug effects. Specifically, the effect of these natural health products was examined on major Phase I drug metabolism enzymes including cytochrome P450, human carboxylesterase-1 and flavin-containing monooxygenases. Several of these natural health products have the potential to cause adverse drug effect through the inhibition of major drug metabolism enzymes. The results indicated that 7 Cree medicines plant extracts inhibited CYP3A4 activity, and 3 of them have been proven to cause potent mechanism-based inactivation of CYP3A4. Seven of eight Traditional Chinese Medicines have been identified as strong CYP3A4 inhibitors; the ethanol extract of Goji has identified as a potent inhibitor for CYP2C9 and 2C19. Goji juice showed universal inhibitory effects on most of the tested enzymes except flavin-containing monooxygenases 3.
835

Potencial do treinamento físico aeróbio para a prevenção do diabetes tipo 2 induzido por dieta de cafeteria: papel do tecido adiposo branco. / Potential of aerobic exercise for the prevention of type 2 diabetes induced by cafeteria diet: role of white adipose tissue

Talita Sayuri Higa 04 December 2012 (has links)
Evidências na literatura demonstraram que o aumento da adiposidade confere maior suscetibilidade ao desenvolvimento de diabetes tipo 2, pois o tecido adiposo branco (TAB) atua na regulação da homeostasia energética e da sensibilidade à insulina através da sua atividade endócrina e de interações com reguladores neuroendócrinos. O treinamento físico aeróbio tem sido fortemente recomendado para a prevenção e tratamento do diabetes tipo 2, pois promove adaptações no metabolismo energético que contribuem diretamente para a melhora da resposta glicêmica e para o controle de peso corporal. Embora esteja claro na literatura o papel do treinamento físico contra o desenvolvimento de distúrbios no metabolismo da glicose e obesidade, uma lacuna de conhecimento ainda existe quando buscamos informações a respeito da participação metabólica do TAB na prevenção do diabetes tipo 2 através do treinamento físico aeróbio. Dessa forma, o presente estudo teve como objetivo testar a hipótese de que o efeito protetor do treinamento físico contra o desenvolvimento de diabetes tipo 2 é mediado por adaptações funcionais do TAB. Para isso, foram utilizados camundongos alimentados com dieta normocalórica e de cafeteria submetidos ou não ao treinamento físico aeróbio. O treinamento físico aeróbio foi eficaz para a prevenção do diabetes tipo 2, e essa resposta foi associada à menor adiposidade corporal resultante do aumento da lipólise e da capacidade oxidativa do TAB induzido pela maior ativação via da AMPK/ACC / Evidence in the literature have shown that increased adiposity confers greater susceptibility to developing type 2 diabetes and white adipose tissue (WAT) acts in the regulation of energy homeostasis and insulin sensibility through its endocrine activity and interaction with neuroendocrine regulators. Aerobic physical training has been strongly recommended for the prevention and treatment of type 2 diabetes because it promotes adaptations in the energy metabolism that contribute directly to the improvement of glycemic metabolism and body weight control. Although it is clear in the literature the role of physical training against the development of disturbances in the glucose metabolism and obesity, the role of WAT to prevent type 2 diabetes through physical training was poorly investigated. Thus, the present study aimed to test the hypothesis that the protective effect of physical training against the development of type 2 diabetes is mediated by functional adaptations of WAT. For this, we used mice fed with control or cafeteria diet and submitted or not to aerobic physical training. The physical training was effective for the prevention of type 2 diabetes, and this response was associated with lower body fat due to increased lipolysis and oxidative capacity of WAT induced by the activation of AMPK/ACC
836

Njurstatus i samband med metforminbehandling och jodkontrast vid DT-undersökningar : En enkätstudie / Renal function in connection with metformin treatment and iodine contrast in CT-examinations

Karlsson, Matilda, Krakys, Evelina January 2020 (has links)
Metformin är förstahandsvalet för behandling av diabetes mellitus typ 2. Genom att öka känsligheten för insulin och minska leverns produktion av glukos har läkemedlet en framgångsrik effekt att sänka blodsockret hos diabetespatienter. Dosen metformin bör på grund av dess utsöndring via njuren anpassas efter patientens njurfunktion. Risken att drabbas av en njurskada efter tillförd jodkontrast administrerad i blodbanan har länge övervärderats och laktatacidos sekundärt till metforminbehandling och kontrastmedel är ovanlig. Därför har Svensk uroradiologisk förening (SURF) kommit med nya rekommendationer för rådande behandlingssituationer gällande metformin i samband med jodkontrastundersökningar. Syfte med studien är att kartlägga hur röntgenkliniker i Sverige arbetar med njurstatus och utsättande av metformin i samband med jodkontrastadministrerade DT-undersökningar med utgångspunkt i SURFs rekommendationer gällande metformin och jodkontrast. Studien är en enkätstudie med kvantitativ ansats som baseras på data från universitetssjukhus och medelstora sjukhus i Sverige. Resultat baseras på 34 klinikers svar och redovisas utifrån varje fråga. Resultatet visar klinikernas svarsfördelning och följsamhet i rekommendationerna. Slutsatsen av studien visar att klinikerna följer rekommendationerna övervägande bra. De flesta klinikerna värderar diabetes mellitus typ 2 patienters njurfunktion i samband med jodkontrastundersökningar.
837

Upplevelse av egenvård hos personer med diabetes mellitus typ 2 : En kvalitativ litteraturöversikt

Johansson, Madeleine, Hedman, Amanda January 2020 (has links)
Bakgrund: Diabetes mellitus typ 2 anses vara en välfärdssjukdom där antalet som har sjukdomen ökar i världen. En viktig del av behandlingen är egenvård där personen med diabetessjukdomen har ett stort egenansvar. Vilket kan innebära livsstilsförändringar med nya rutiner. Sjuksköterskan har ett ansvar att ge personen information och kunskap om sjukdomen för att personen ska kunna utföra egenvården. Egenvården innefattar bland annat att ha kunskap om blodsocker, kost och fysisk aktivitet och hur det påverkar diabetessjukdomen. Syfte: Att beskriva upplevelsen av egenvård hos personer med diabetes mellitus typ 2. Metod: En kvalitativ litteraturöversikt med en sammanställning av 13 vetenskapliga artiklar. Vid analysen följdes Fribergs femstegsanalys. Resultat: I litteraturöversiktens resultat framkom två huvudteman: ”Innebar livsstilsförändringar” och ”Betydelsefullt med stöd”.  Svårigheter som uppstod i egenvården var ändrade kostvanor, fysisk aktivitet och förändrade vardagsrutiner. Resultatet visade att egenvården har en del utmaningar där stöd från omgivningen och hälso- och sjukvårdspersonal kan underlätta hur egenvården upplevdes.  Slutsats: Hanteringen av egenvården innebar förändrade levnadsvanor där anpassningen till det nya livet gick olika fort. Stöd från omgivningen och hälso- och sjukvården hade en stor betydelse i hur egenvården fungerade och upplevdes. / Background: Type 2 diabetes mellitus is a welfare disorder in which the number of people with the disease is increasing in the world. An important part of the treatment is self-care where the person with the diabetes disease has a great responsibility. The nurse has a responsibility to provide the person with information and knowledge about the illness for the person to be able to perform self-care. Aim: To describe the experience of self-care in people with diabetes mellitus type 2. Method: A qualitative literature review with a compilation of 13 scientific articles. The analysis followed Friberg's five-step analysis. Results: The two main themes developed in the literature review's results: "Means lifestyle changes" and "Significant with support". Difficulties that arose in self-care were changing dietary habits, physical activity and changing daily routines. The result showed that self-care has some challenges in which support from the environment and health care personnel can facilitate how self-care was experienced. Conclusion: Managing self-care meant changing living habits where adaptation to the new life went very fast. Support from the environment and health care played a major role in how self-care worked and was experienced.
838

Rôle des interactions entre la mitochondrie et le reticulum endoplasmique dans les défauts de sécrétion d'insuline par les cellules béta pancréatiques au cours du diabète de type 2 / Role of the interaction between the mitochondria and the endoplasmic reticulum in the pancreatic beta cell failure during type 2 diabetes

Dingreville, Florian 19 December 2018 (has links)
La mitochondrie et le réticulum endoplasmique (RE) forment un réseau dans les cellules qui contrôle la fonction et le destin cellulaire. La mitochondrie de la cellule ß pancréatique joue un rôle central dans la sécrétion d’insuline en réponse au glucose de par sa capacité à produire de l’ATP. Le RE lui prend en charge la mise en conformation de l’insuline et joue le rôle de stock calcique. Ces 2 organites se rejoignent au niveau de points de contact appelés Mitochondria Associated endoplasmic reticulum Membranes (MAMs,). Les MAMs sont le siège d’échanges calciques et lipidiques entre les 2 organites. Les altérations de la mitochondrie et du RE ont été montrées comme des facteurs contribuant au développement du diabète de type 2. L’implication des MAMs n’a cependant jamais été étudiée dans la cellule ß.La glucotoxicité provoquée par une exposition chronique à des concentrations élevées de glucose, est un facteur clé de la dysfonction ß pancréatique au cours du diabète de type 2. J’ai pu démontrer que la glucotoxicité augmentait la fission mitochondriale et le nombre de MAMs dans les cellules bêta humaines et INS-1E mais que ces MAMs présentaient des défauts d’échanges calciques, pouvant ainsi contribuer au défaut de la sécrétion d’insuline. J’ai ensuite modulé les MAMs soit via une stimulation aigue au glucose soit par l’utilisation d’un siRNA qui rompt partiellement les contacts entre le RE et la mitochondrie ou par l’utilisation d’un linker qui artificiellement force ces contacts. La stimulation aigue au glucose augmente les MAMs et le transfert de calcium du RE vers la mitochondrie alors que la rupture des contacts diminue la secretion d’insuline. Enfin le linker en forçant les rapprochements RE-mitochondrie mime les effets de la glucotoxicité.Ce travail, constitue la première étude structurelle et fonctionnelle des MAMs dans la cellule ß pancréatique, éclairant leur rôle dans la dysfonction ß pancréatique lors du développement du diabète de type 2 / Mitochondria and endoplasmic reticulum (ER) form a network in cells that control cellular function and fate. Mitochondria play a central role in insulin secretion in ß cell by its ability to product ATP. ER takes in charge of insulin folding and is the major cell calcium store. Both organelles interact at contact sites, defined as mitochondria-associated membranes (MAMs), a multiprotein complex implicated in calcium transfer and lipid exchange . Alterations of mitochondria and ER have been shown to contribute to metabolic disorder such as type 2 diabetes. MAMS were recently implicated in the regulation of glucose homeostasis But the role of MAMs in ß cells is still largely unknown and their implication in glucotoxicity-associated ß cell dysfunction remains to be defined.Here, I report that acute glucose stimulation stimulated ER-mitochondria interactions and calcium (Ca2+) exchange in INS-1E cells, whereas disruption of MAMs altered glucose-stimulated insulin secretion (GSIS). Conversely, chronic incubations with high glucose of either INS-1E cells or human pancreatic islets altered GSIS, and concomitantly reduced ER Ca2+ store, increased mitochondrial Ca2+ and reduced ATP-stimulated ER-mitochondria Ca2+ exchanges, despite an increase of organelle interactions. Furthermore, glucotoxicity-induced perturbations of Ca2+ signalling are associated with ER stress, altered mitochondrial respiration and mitochondria fragmentation, and these organelle stresses may participate to increased organelle tethering, as a protective mechanism. Lastly, sustained induction of ER-mitochondria interactions using a linker induced mitochondrial fission and altered GSIS.Therefore, dynamic organelle coupling participates to GSIS in ? cells and over-time disruption of organelle Ca2+ exchange might be a novel mechanism contributing to glucotoxicity-induced ß cell dysfunction in type 2 diabetes
839

Dietary Factors, Type 2 Diabetes and Diabetic Retinopathy / Facteurs alimentaires, diabète de type 2 et rétinopathie diabétique

Dow, Courtney 12 October 2018 (has links)
Contexte : Le diabète de type 2 (DT2) constitue une pathologie majeure, au lourd fardeau, associ ée à de nombreuses complications, comme la rétinopathie diabétique (RD). Des facteurs modifiables, comme l’alimentation, ont déjà été identifiés pour le DT2 et la RD mais certains aspects de leurs rôles restent à préciser. Objectifs : Les objectifs de cette thèse étaient d’examiner le rôle de l’alimentation, en particulier la consommation d’acides gras (AGs), et des autres facteurs modifiables liés au mode de vie sur le risque de DT2 et de synthétiser, interpréter et analyser la relation entre l’alimentation et la RD. Résultats : Les résultats suggèrent que le rôle des AGs sur le risque de DT2 et de la RD pourrait être différent selon leur type, et même varier au sein d’un groupe comme les AG polyinsaturés (AGPI). Les résultats suggèrent aussi qu’une forte adhésion aux recommandations alimentaires n’est pas associée avec le développement d’un DT2, mais en revanche une forte adhérence aux autres recommandations de santé (concernant le tour de taille, l’activité physique et le statut tabagique) est fortement associée avec un moindre risque de DT2. On a montré qu’avoir un mode de vie sain aurait pu empêcher la survenue de plus de la moitié des cas de DT2. Conclusions : Cette thèse a permis de préciser l’importance et la complexité du rôle de l’alimentation dans le développement du DT2 et de la RD. Elle montre aussi l’impact des comportements sains dans la pathologie de DT2 et confirme que le DT2 est en grande partie, une maladie évitable. Les efforts devraient se focaliser sur la modification des comportements de santé à la fois dans la population générale et atteinte de DT2 et notamment encourager une alimentation modérée et variée. / Background : Type 2 diabetes (T2D) presents a significant health burden that is associated with many complications, such as diabetic retinopathy (DR), that further burden people with diabetes. Modifiable risk factors, such as the diet, have been identified for both T2D and DR; yet certain aspects of the role of the diet remain unclear. Objectives : The main objectives of this thesis were therefore to examine the role and impact of the diet, and in particular, the consumption of fatty acids (FAs), and other modifiable behaviours on the risk of T2D and to summarize, interpret and analyze the relationship between the diet and DR using data from both the E3N and AusDiab cohort studies. Results : The results suggest that the role of FAs on the risk of T2D and DR may differ between and within subgroups, and by individual polyunsaturated fatty acids (PUFAs). The findings also suggest that strongly adhering to national dietary guidelines is not associated with the development of T2D, but strongly adhering to other recommendations for healthy behaviours (for waist circumference, physical activity and smoking) is strongly inversely associated with T2D. Modifiable behaviour could have prevented more than half of the cases of T2D. Conclusions : This work underlines the importance and the complexity of the role of the diet in the development of T2D and DR. It also illustrates the impact of healthy behaviour in the etiology of T2D and confirms that T2D is largely preventable. Efforts should focus on the modification of multiple healthy behaviours in populations, and promote diets that are moderate and widely varied.
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A Technological Solution to Identify the Level of Risk to Be Diagnosed with Type 2 Diabetes Mellitus Using Wearables

Nuñovero, Daniela, Rodríguez, Ernesto, Armas, Jimmy, Gonzalez, Paola 01 January 2021 (has links)
El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / This paper proposes a technological solution using a predictive analysis model to identify and reduce the level of risk for type 2 diabetes mellitus (T2DM) through a wearable device. Our proposal is based on previous models that use the auto-classification algorithm together with the addition of new risk factors, which provide a greater contribution to the results of the presumptive diagnosis of the user who wants to check his level of risk. The purpose is the primary prevention of type 2 diabetes mellitus by a non-invasive method composed of the phases: (1) Capture and storage of risk factors; (2) Predictive analysis model; (3) Presumptive results and recommendations; and (4) Preventive treatment. The main contribution is in the development of the proposed application. / Revisión por pares

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