A metformina é uma droga utilizada para tratamento da diabetes tipo 2. O PPAR-α tem um papel central no controle imunometabólico. Portanto, o objetivo do estudo foi avaliar os efeitos imunometabólicos da dieta hiperlipídica (HFD), em camundongos C57BL6 (WT) e knockout para PPAR-α, tratados com metformina. Métodos: Os animais foram submetidos a uma HFD por 12 semanas, nos últimos dez dias de dieta os animais foram tratados com metformina. A oxidação de palmitato no músculo esquelético, As citocinas, no fígado, no tecido adiposo retroperitoneal, em hepatócitos e macrófagos intraperitoneais foram analisados. Resultados: O tratamento aumentou a oxidação de palmitado no músculo, promoveu um efeito anti-inflamatório no tecido adiposo e reverteu à inflamação dos macrófagos. No fígado e nos hepatócitos, a metformina causou um efeito inflamatório. Conclusão: A inflamação hepática foi induzida pelo tratamento e o efeito principal foi a um potencial aumento na inflamação nos hepatócitos. Os macrófagos tiveram uma resposta anti-inflamatória, assim como o tecido adiposo. / Metformin is a drug used to treatment of type 2 diabetes. PPAR-α plays a central role in immunometabolic control. Therefore, the aim of the study was to evaluate the effects of imumnometabolics of high fat diet (HFD) in C57BL6 mice (WT) and knockout for PPAR-α treated with metformin. Methods: The animals were subjected to a HFD for 12 weeks in the last ten days of diet the animals were treated with metformin. The palmitate oxidation in skeletal muscle, cytokines in the liver, in the retroperitoneal adipose tissue, hepatocytes and intraperitoneal macrophages were analyzed. Results: The treatment increased palmitate oxidation in muscle, it has promoted an anti-inflammatory effect in adipose tissue and macrophages to inflammation reversed. In the liver and hepatocytes, metformin caused an inflammatory effect. Conclusion: The liver inflammation was induced, and treatment was a main effect to a potential increase in inflammation in hepatocytes. Macrophages have an anti-inflammatory response, as well as adipose tissue.

Os tumores de musculatura liso do útero se desenvolvem a partir do miométrio e podem apresentar carcterísticas clínicas malignas e benignas. Dentre eles, o leiomiossarcoma (LMS) é o tumor maligno mais comum, com altas taxas de metástase e recidiva, mesmo sendo diagnosticado em estágios iniciais. Já os leiomiomas (LM) são os tumores benignos mais frequentes em mulheres em idade reprodutiva. Ambos possuem mesma diferenciação celular, porém com comportamentos clínico e biológico bastante distintos, e até o momento não se dispõe de tratamento específico ou curativo. Nesse contexto, a busca por novos alvos moleculares pode contribuir não só para um melhor entendimento dessas neoplasias, como também para a descoberta de novas terapias. Em estudo prévio foi observada a expressão aumentada de FOXO3a nos sarcomas uterinos, em comparação aos LMs e ao miométrio adjacente (MM). Além disso, sua expressão foi crescente de acordo com o potencial de malignidade do tumor. Assim, o objetivo do presente estudo foi avaliar in vitro o efeito de terapia alvo específica para FOXO3a em células de LM e LMS. Para isto, linhagens celulares de MM (ATCC PCS-460-011), LM (THESCs - CRL-4003) e LMS (SK-UT-1 - HTB-114) foram caracterizadas quanto à expressão basal de FOXO3a (gene e proteína) e submetidas a tratamento com Genisteína e Metformina ou inativação do gene por siRNA. Os efeitos dos tratamentos foram avaliados por PCR em tempo real, Western Blot, imunocitoquímica, ensaios de proliferação, migração e apoptose. Nossos resultados mostraram que todos os tratamentos realizados interferiram na capacidade de proliferação e migração das células, com maior inibição após as 48 horas nos LMS e 72h nos LM. O efeito obtido na transfecção com siRNA apresentou maior eficiência após 48 h da transfecção nos LMS e 72h nos LM. Os efeitos da inibição de FOXO3a foram maiores na proliferação e migração dos LM, porém os resultados não foram estatisticamente significativos. Dentre as substâncias testadas, a Metformina apresentou maior efeito sobre a proliferação, migração e viabilidade das linhagens celulares. A Genisteína também apresentou efeito inibitório nas células, porém o controle com veículo também apresentou o mesmo efeito citotóxico. De modo geral, os efeitos obtidos com os fármacos, foram tempo e concentração dependentes. Em conjunto, nossos resultados sugerem um relevante do FOXO3a nos tumores de musculatura lisa uterinos, além de apresentá-lo como potencial alvo para terapia específica / Smooth muscle tumors of the uterus develop from the myometrium and may present benign and malignant clinical features. Among them, leiomyosarcoma (LMS) is the most frequent malignant tumor, with high rates of metastasis and relapse, even when diagnosed in early stages. On the other hand, leiomyomas (LM) are the most frequent benign tumors in women of reproductive age. Both have the same cellular differentiation, but with very different clinical and biological behaviors, and so far no specific or curative treatment is available. In this context, the search for new molecular targets can contribute not only for a better understanding of these neoplasms, but also for the discovery of new therapies. In a previous study, increased expression of FOXO3a in uterine sarcomas was observed, compared to LMs and adjacent myometrium (MM). In addition, its expression was increasing according to the malignancy potential of the tumor. Thus, the aim of the present study was to evaluate in vitro, the effect of specific targeted therapy for FOXO3a on LM and LMS cells. For this, MM (ATCC PCS-460-011), LM (THESCs-CRL-4003) and LMS (SK-UT-1-HTB-114) cell lines were characterized for basal expression of FOXO3a (gene and protein) and subsequently submitted to treatment with metformin and genistein, or silencing of FOXO3a by siRNA. The effects of the treatments were evaluated by real-time PCR, Western Blot, immunocytochemistry, proliferation, migration and apoptosis assays. Our results showed that all treatments interfered in the proliferation and migration capacity of the cells, with greater inhibition after 48 hours for LMS and 72 hours LM. The effect obtained in the transfection with siRNA showed higher efficiency after 48 hours of transfection in LMS and 72 hours in LM. The effects of inhibition of FOXO3a were greater in the proliferation and migration of the LM, but the results were not statistically significant. Among the substances tested, Metformin had a greater effect on proliferation, migration and viability of the cell lines. Genistein also had an inhibitory effect on the cells, but the control with the vehicle also presented the same cytotoxic effect. In general, the effects obtained with the drugs were time and concentration dependent. Together, our results suggest a relevant role of FOXO3a in uterine smooth muscle tumors, in addition to presenting it as a potential target for specific therapy

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Objetivo: A resistÃncia insulÃnica com hiperinsulinemia compensatÃria exerce importante papel fisiopatolÃgico na SÃndrome dos OvÃrios MicropolicÃsticos (SOMP). Neste sentido o uso de substÃncias sensibilizantes à insulina, dentre as quais a melhor estudada à a metformina, tem sido proposto como terapia inicial na patologia. Nosso estudo se propÃe a avaliar a efetividade da metformina na dose de 1.000 mg ao dia por 90 dias, nos parÃmetros antropomÃtricos, metabÃlicos, da morfologia ultrassonogrÃfica ovariana, e dos efeitos colaterais, em pacientes portadoras de SOMP. Pacientes e MÃtodo: Ensaio clÃnico prospectivo, randomizado por tabela de nÃmeros aleatÃrios, duplo-cego e controlado por placebo, com 21 pacientes com SOMP, sendo 13 alocadas no grupo experimental (metformina), e oito alocadas no grupo controle (placebo). Foram analisados e comparados as mÃdias e desvio-padrÃes dos parÃmetros dentro de cada grupo, e entre os grupos, no recrutamento do estudo e apÃs 90 dias de tratamento. Resultados: As mÃdias das medidas basais das variÃveis estudadas foram semelhantes entre os grupos garantindo sua comparabilidade. As pacientes tratadas com metformina obtiveram reduÃÃo significativa de sua circunferÃncia da cintura e glicemia de jejum. Todos os outros parÃmetros analisados nÃo mostraram diferenÃa significativa entre os grupos. Efeitos colaterais foram relatados por 92,31% e 71,43% das pacientes dos grupos experimental e controle, respectivamente. Apenas trÃs (23,07%) pacientes do grupo experimental e nenhuma do grupo controle reportaram efeitos colaterais graves que requereram ajustes da medicaÃÃo. NÃo houve abandono da terapia ou perda de seguimento.ConclusÃo: o uso da metformina na dose de 1.000 mg por 90 dias reduziu significativamente a circunferÃncia da cintura e a glicemia de jejum em pacientes com SOMP, com boa tolerabilidade geral e mÃnima incidÃncia de efeitos colaterais relevantes. Talvez a melhora de parÃmetros mais diretamente relacionados à resistÃncia insulÃnica como a relaÃÃo cintura/quadril requeira doses mais altas e/ou maior tempo de administraÃÃo. / Objectives: Insulin resistance that leads to hyperinsulinaemia plays major pathogenic role in Polycystic Ovary Syndrome. This way, the use of insulin-sensitizing agents, like metformin that has been the most extensively studied drug, is suggested as the initial therapy for the disease. Our aim was to evaluate the effectiveness of metformin 1,000 mg a day for 90 days in anthropometric and metabolic measurements, ovarian ultrasonographic morphology, and side effects, on patients with Polycystic Ovary Syndrome (PCOS). Patients and Method: A randomized, by means of random numbers table, double-bind, placebo-controlled trial, including 21 PCOS patients. Thirteen patients were allocated at the treatment (metformin) group, and eight at the placebo group. The mean and standard-deviation of the measures were taken and analyzed into each group and between the groups on recruitment of the trial and after 90 days. Results: The mean values of the studied baseline characteristics were similar between the groups. The metformin group had significant reductions on waist circumference and fasting glucose. There were no significant differences in any other of the measurements. Side effects were referred by 92.31% and 71.43% of the treatment and placebo groups, respectively. Only three (23.07%) patients of treatment group and none of placebo group referred major side effects that request drug dose adjust. There were no drop-outs or lost of follow up. Conclusions: metformin at doses of 1,000 mg a day for 90 days was effective at waist circumference and fasting glucose reduction on PCOS patients, with good acceptance and mild side effects. Improvement of characteristics more related to insulin resistance, like the waist/hip ratio, probably need higher doses or longer course of use.

Objetivo: Avaliar o controle glicêmico em pacientes que utilizaram metformina ou insulina para tratamento do diabetes gestacional, identificando fatores preditores da necessidade de insulina complementar nas pacientes que tiveram, como terapêutica inicial, a metformina. Método: pacientes com DG que não obtiveram controle glicêmico com dieta e exercícios físicos foram randomizadas para receber metformina (n=46) ou insulina (n=46). Os critérios de inclusão foram: gestação única, realização de dieta e exercícios físicos por período mínimo de uma semana, sem controle glicêmico satisfatório, ausência de fatores de risco para acidose láctica, ausência de anormalidades anatômicas e/ou cromossômicas do produto conceptual. Foram excluídas as gestantes que apresentaram perda de seguimento pré-natal. Resultado: A comparação das médias glicêmicas pré-tratamento medicamentoso não mostrou diferença estatisticamente significativa entre os grupos (p=0,790). Porém, após a introdução dos medicamentos, foram observados médias glicêmicas menores no grupo metformina, ao longo do dia (p=0,020), principalmente, após o jantar (p=0,042). Pacientes que utilizaram metformina tiveram menor ganho de peso (p=0,002) e, também, menor frequência de hipoglicemia neonatal (p=0,032). Doze pacientes do grupo metformina (26,08%) necessitaram de insulina complementar para controle glicêmico. A idade gestacional precoce (odds ratio 0,71, CI95% 0,52-0,97; p=0,032) e a média glicêmica pré-tratamento medicamentoso (odds ratio 1,061, CI95% 1,001-1,124; p=0,046) foram identificadas como preditoras da necessidade de insulina complementar. Conclusão: A metformina foi eficaz em propiciar controle glicêmico adequado, com menor ganho de peso e menor frequência de hipoglicemia neonatal. Foi identificado grupo de pacientes com maior probabilidade de necessitar de complementação com insulina para atingir controle glicêmico / Objective: To evaluate glycemic control in women receiving metformin or insulin for the treatment of gestational diabetes, and to identify factors predicting the need for supplemental insulin in women initially treated with metformin. Methods: Women with gestational diabetes who did not achieve glycemic control with diet and exercise were randomized to receive either metformin (n=46) or insulin (n=46). Criteria for inclusion were singleton pregnancy, diet and exercise for a minimum period of one week without satisfactory glycemic control, absence of risk factors for lactic acidosis, and absence of anatomic and/or chromosome anomalies of the conceptus. Patients who were lost to prenatal follow-up were excluded. Results: Comparison of mean pretreatment glucose levels showed no significant difference between groups (P=.790). However, lower mean glucose levels across the day were observed in the metformin group after introduction of the drug (P=.020), especially after dinner (P=.042). Women using metformin presented less weight gain (P=.002) and a lower frequency of neonatal hypoglycemia (P=.032). Twelve women in the metformin group (26.08%) required supplemental insulin for glycemic control. Early gestational age (OR=0.71, 95%CI: 0.52-0.97; P=.032) and mean pretreatment glucose level (OR=1.061, 95%CI: 1.001-1.124; P=.046) were identified as predictors of insulin need. Conclusion: Metformin was found to provide adequate glycemic controlwith lower mean glucose levels across the day, less weight gain and a lower frequency of neonatal hypoglycemia. Logistic regression analysis showed that gestational age at diagnosis and mean pretreatment glucose level were predictors of the need for supplemental insulin therapy in women initially treated with metformin

O endométrio é a mucosa que reveste o útero. A receptividade uterina é definida como um estado em que o endométrio se encontra receptivo à implantação do blastocisto. E, a preparação do endométrio para a implantação não é somente uma questão de estimulação hormonal adequada, depende da interação entre o blastocisto e o endométrio. Esta interação envolve uma complexa sequência de eventos de sinalização e uma variedade de moléculas. As concentrações de interleucina-8 (IL-8) e interleucina-1β (IL-1β) estão correlacionadas com o processo de implantação. Em humanos, a taxa de insucesso desse processo é alta e ocasionada por diversos fatores. A síndrome dos ovários policísticos (SOP) é um distúrbio endócrino-ginecológico que afeta de 6 a 8 % das mulheres em idade reprodutiva, e se caracteriza, principalmente, por anovulação crônica e hiperandrogenismo, estando diretamente relacionada à infertilidade feminina. Apesar da incerteza sobre a causa primária da SOP, há relatos sobre a importância da hiperinsulinemia na sua promoção. O objetivo deste trabalho foi estabelecer um modelo de hiperinsulinemia e hiperandrogenismo em células estromais endometriais in vitro, simulando características de SOP; identificar o melhor gene normalizador para estudos de expressão gênica em amostras das células em cultivo; avaliar o efeito da metformina sobre a proliferação celular e expressão gênica da IL-8 e IL-1β no modelo proposto. O tecido endometrial foi obtido de pacientes submetidas a histerectomia. A cultura primária das células estromais foi padronizada e as células foram divididas em sete grupos de tratamento: estradiol (G1); estradiol e progesterona (G2); estradiol, progesterona e insulina (G3); estradiol, progesterona e diidrotestosterona (G4); estradiol, progesterona e metformina (G5); estradiol, progesterona, insulina e diidrotestosterona (G6); estradiol, progesterona, insulina, diidrotestosterona e metformina (G7). Foi realizada análise de imunocitoquímica para vimentina para confirmação do cultivo com células estromais. Para avaliar a viabilidade e proliferação celular ao longo do tempo foi utilizado o ensaio de MTT em dois tempos diferentes de cultivo. As extrações de RNA foram realizadas e o cDNA obtido das amostras foi utilizado para a amplificação do mRNA de cinco genes candidatos a normalizadores e para avaliar a expressão dos genes da IL-8 e IL-1β através de PCR em tempo real.O estabelecimento da cultura de células estromais foi confirmado através da coloração positiva para a proteína vimentina. As células mantiveram-se viáveis durante todo o período de cultivo, apresentando aumento significativo na proliferação celular no tempo 8 em relação ao tempo 4 em todos os grupos. O grupo G7 (tratado durante 48 horas com metformina) apresentou uma menor taxa de proliferação em relação aos grupos G2, G3 e G6. Para análise de expressão gênica nestas células, o gene que mostrou os melhores parâmetros de estabilidade de expressão no modelo celular proposto foi o gene HPRT1. Observamos uma maior expressão do gene da IL-8 no grupo G5 tratado durante 48 horas em relação ao mesmo grupo tratado durante o período de 24 horas. Verificou-se maior expressão do gene da IL-1β no grupo G5 quando comparado a todos os outros grupos no período de 48 horas de tratamento com metformina. Entretanto, o grupo G7, também tratado com metformina, não apresentou diferença estatística em relação ao tempo de tratamento em nenhum dos genes estudados. Esses resultados demonstram que o modelo de hiperinsulinemia e hiperandrogenismo em cultura de células estromais endometriais é viável. Neste modelo, em que foram testados cinco genes em relação à sua estabilidade de expressão, o gene HPRT1 apresentou uma boa estabilidade, ao contrário de outros genes frequentemente utilizados como genes de referência. O tratamento com metformina apresentou um efeito antiproliferativo nas células do grupo hiperinsulinêmico e hiperandrogênico. No período de 48 horas aumentou a expressão do gene da IL-1β no grupo tratado somente com o medicamento. Sugerindo uma ação inibitória da insulina sobre a expressão dos genes da IL-8 e IL-1β no grupo hiperinsulinêmico e hiperandrogênico. Mais estudos são necessários para melhor entendimento do efeito da metformina nos fatores envolvidos durante a implantação. / The endometrium is the mucosa lining the uterus. The uterine receptivity is defined as a condition in which the endometrium is receptive to implantation of the blastocyst. The preparation of the endometrium for implantation is not only a matter of proper hormonal stimulation, it depends on the interaction between the blastocyst and the endometrium. This interaction involves a complex sequence of events and a variety of signaling molecules. The concentrations of interleukin-8 (IL-8) and interleukin-1β (IL-1β) are correlated to the implantation process. In humans, the failure rate of this process is high and caused by several factors. The polycystic ovary syndrome (PCOS) is an endocrine-gynecological disorder that affects from 6 to 8 % of women of reproductive age. It is characterized mainly by chronic anovulation and hyperandrogenism and directly related to female infertility. Despite the uncertainty about the primary cause of PCOS, there are reports about the importance of hyperinsulinemia in promoting it. The aim of this study was to establish a model of hyperinsulinemia and hyperandrogenism in endometrial stromal cells in vitro, simulating features of PCOS; to identify the best housekeeping gene for gene expression studies in the cultured cells; to evaluate the effects of metformin on cell proliferation, as well as IL-8 and IL-1β gene expression in the proposed culture model. The human endometrial tissue was obtained from patients undergoing hysterectomy. The primary culture of stromal cells was standardized and divided into seven treatment groups: estradiol (G1); estradiol and progesterone (G2); estradiol, progesterone and insulin (G3); estradiol, progesterone and dihydrotestosterone (G4); estradiol, progesterone and metformin (G5); estradiol, progesterone, insulin and dihydrotestosterone (G6); estradiol, progesterone, insulin, dihydrotestosterone and metformin (G7). Immunocytochemistry analysis for vimentin were performed. Cell viability and proliferation were evaluated by MTT assay at two days in different times of cultivation. RNA extractions were performed and the cDNA obtained from primary culture was used to amplify five candidates to housekeeping genes mRNA and to evaluate IL-8 and IL1β expression by real time PCR. The stromal culture cell establishment was confirmed by positive staining for vimentin. The cells remained viable throughout the cultivation period, with significant cell proliferation increase at day 8 compared to day 4 in all groups. The G7 group (metformin treated for 48 hours) showed lower proliferation rate than G2, G3 and G6 groups. For gene expression analysis in these cells, the gene showing the best parameters of stability of expression was HPRT1. Increased gene expression of IL-8 was observed in G5 group treated for 48 hours compared to the same group during 24 hours. Similarly, the G5 group showed higher IL-1β gene expression when compared to all other groups treated with metformin for 48 hours. However, the G7 group, also metformin treated, did not show statistically significant difference in treatment time of any studied genes. These results suggest that model of hyperinsulinemia and hyperandrogenism in endometrial stromal cells is viable and provides a good cell sampling to molecular analysis under different experimental conditions. In this model, several genes were tested for expression stability. HPRT1 presented the best values, unlike others classical housekeeping genes. The metformin treatment showed an antiproliferative effect on cells in hyperinsulinemic and hyperandrogenic group and at 48 hours increased IL-1β gene expression in the treated group with the drug alone. It suggests an inhibitory action of insulin on these genes expression in the hyperinsulinemic and hyperandrogenic group. More studies are needed to better understand the effect of metformin on the factors involved during implantation.

Les leucémies aiguës lymphoblastiques et les lymphomes de type T sont des cancers très agressifs, génétiquement hétérogènes. Les pronostics sont globalement défavorables et la survie après rechute n’est que de 10%. Les plus fréquentes mutations ont pour conséquence l’activation constitutive de l’axe PI3K/AKT/mTOR favorisant la progression tumorale. La compréhension des mécanismes de la transformation cancéreuse, à l’aide d’un modèle murin (invalidation spécifique de PTEN dans les lymphocytes T), va permettre de proposer de nouvelles cibles potentielles et de futurs traitements ciblés qui peuvent agir seuls ou en combinaison avec les médicaments chimiothérapeutiques et améliorer le pronostic et la survie des patients. Dans un premier temps, je me suis intéressée au fait de cibler à la fois le métabolisme leucémique élevé et l’activation oncogénique de la voie mTOR en utilisant des activateurs du senseur de stress AMPK : metformin, phenformin et AICAR. Puis, comme il est connu que la concentration en acides aminés intracellulaire influe sur la voie mTOR je me suis intéressée à interférer avec l’action du transporteur d’acides aminés LAT-1, dont le gène slc7a5 est fortement surexprimé dans un grand nombre de cancers dont notre modèle de lymphome T tPTEN-/-. Enfin, je me suis intéressée aussi au rôle de la surrexpression du récepteur de la transferrine (CD71) par les cellules tPTEN-/-, qui suggère que ces cellules cancéreuses pourraient avoir développé une addiction au fer, co-facteur essentiel de nombreux processus métaboliques. Globalement, les résultats présentés dans ce mémoire de thèse démontrent l’intérêt de cibler le métabolisme reprogrammé des cellules cancéreuses. / Lymphoids proliferative malignancies of T-cell origin, lymphomas (T-NHL) and acute lymphoblastic leukemias (T-ALL), are genetically heterogeneous and very aggressive diseases. Their prognosis is still unfavourable and relapse-free survival is only 10%. A common feature of T-LL/T-ALL is the frequent (85% of cases) and abnormal activation of the PI3K/AKT/mTOR pathway that promotes tumor progression. A better molecular understanding of tumoral transformation, using a murine model (T-cell-specific depletion of PTEN), will help identify new potential therapeutic targets for future innovative treatments, that could be efficient alone or in combination with current chemotherapeutic drugs to improve prognosis and patients survival. First of all, I was interested in studying the effects of interfering with the high metabolism and the oncogenic activation of the mTOR pathway, by using metformin, phenformin and AICAR that activates the stress and energy sensor AMPK. Next, as it was well known that intracellular amino acids concentration influences the mTOR pathway, I explored the possibility to target the amino acids transporter LAT-1 that is encoded by the slc7a5 gene, upregulated in a large numbers of cancers including our T-lymphoma murine model. Lastly, I also observed an upregulation of the transferrin receptor (CD71) in tPTEN-/- cells, suggesting that cancer cells require high levels of iron uptake, an essential element for numerous metabolic processes, to sustain high proliferation and survival. More generally, the results presented in this manuscript thesis show an interest to target the reprogrammed metabolism of tumor cells.

<p>Excessive weight gain has frequently been reported in adolescents with type 1 diabetes, especially in girls. In general, puberty is associated with reduced insulin sensitivity that is further diminished by overweight. The causes and consequences of excessive weight gain in adolescents with type 1 diabetes are not fully understood. The studies described in this thesis addressed body composition in adolescents with type 1 diabetes and the relationships between physical activity, energy intake and changes in body composition. Furthermore, the effect of metformin as additional therapy on glycaemic control and insulin sensitivity was examined in a randomised placebo-controlled study. Body mass index (BMI) and percentage body fat (%BF) were significantly higher in girls with type 1 diabetes compared to healthy control girls. Mean HbA1c during puberty, but not mean insulin dose, was positively related to BMI at the age of 18 in girls with diabetes. A centralised fat distribution was associated with poor glycaemic control, increased daily dosage of insulin and elevated cholesterol and triglyceride levels. Neither total physical activity nor total energy intake differed between adolescent girls with type 1 diabetes and healthy age-matched control girls. A high dietary fat intake was positively related to gain in %BF in girls with type 1 diabetes. Additional therapy with metformin for three months improved glycaemic control and peripheral insulin sensitivity in adolescents with poorly controlled type 1 diabetes. The improvement in glycaemic control was related to insulin sensitivity at baseline, implying that the most insulin resistant subjects benefited most from the metformin therapy. It is concluded that the excessive weight gain observed in girls with type 1 diabetes is mainly attributable to an increased fat mass and that dietary fat intake is of importance for this gain in body fat. Additional treatment with metformin improves glycaemic control in adolescents with poorly controlled type 1 diabetes.</p>

Excessive weight gain has frequently been reported in adolescents with type 1 diabetes, especially in girls. In general, puberty is associated with reduced insulin sensitivity that is further diminished by overweight. The causes and consequences of excessive weight gain in adolescents with type 1 diabetes are not fully understood. The studies described in this thesis addressed body composition in adolescents with type 1 diabetes and the relationships between physical activity, energy intake and changes in body composition. Furthermore, the effect of metformin as additional therapy on glycaemic control and insulin sensitivity was examined in a randomised placebo-controlled study. Body mass index (BMI) and percentage body fat (%BF) were significantly higher in girls with type 1 diabetes compared to healthy control girls. Mean HbA1c during puberty, but not mean insulin dose, was positively related to BMI at the age of 18 in girls with diabetes. A centralised fat distribution was associated with poor glycaemic control, increased daily dosage of insulin and elevated cholesterol and triglyceride levels. Neither total physical activity nor total energy intake differed between adolescent girls with type 1 diabetes and healthy age-matched control girls. A high dietary fat intake was positively related to gain in %BF in girls with type 1 diabetes. Additional therapy with metformin for three months improved glycaemic control and peripheral insulin sensitivity in adolescents with poorly controlled type 1 diabetes. The improvement in glycaemic control was related to insulin sensitivity at baseline, implying that the most insulin resistant subjects benefited most from the metformin therapy. It is concluded that the excessive weight gain observed in girls with type 1 diabetes is mainly attributable to an increased fat mass and that dietary fat intake is of importance for this gain in body fat. Additional treatment with metformin improves glycaemic control in adolescents with poorly controlled type 1 diabetes.

Recent statistics show that approximately 415 million people worldwide have diabetes. Glycated haemoglobin (HbA1c) measurements were introduced many years ago as the gold standard tool for detecting and monitoring treatment as well as making management decisions for diabetic patients. Glycated haemoglobins are formed by the non-enzymatic glycation of haemoglobin molecules. This non-enzymatic glycation process has been strongly related to pathogenesis of chronic complications associated to diabetes. It was suggested that this glycation process may be moderated by an enzymatic deglycation process thought to involve a deglycating enzyme known as Fructosamine-3-kinase (FN3K), an enzyme that deglycates the glycated haemoglobin in erythrocytes and other glycated proteins in other tissues. FN3K acts through phosphorylation of fructosamines on the third carbon of their sugar moiety, making them unstable and consequently causing them to detach from the protein. The degree of deglycation is thought to depend on the activity of the FN3K enzyme. Moreover, variation in the activity of FN3K between individuals is hypothesised to lead to apparent differences in glycated haemoglobin levels: some individuals have high rates of deglycation so that they tend to have lower average glycaemia than actually the case, while others with low rates of deglycation appear to have higher than actual glycaemia (known as the glycation gap, G-gap). The G-gap has been reported to be associated with alteration of diabetic complications risk. The G-gap reflects the discrepancy between average glycaemia as determined from glycated haemoglobin (measured as HbA1c) and that from the determination of fructosamine. The positive G-gap is defined as a higher level of glycation of proteins than expected whereas a negative G-gap means a lower level of glycation than expected. To explore the role of FN3K in diabetes and other associated morbidities, we decided to divide our research into 3 studies. Each study was categorised according to the type and the source of samples involved. The first study explored the correlation between FN3K activity and protein level with G-gap data; it involved 148 diabetic patients who were recruited at New Cross Hospital, Wolverhampton, selected as having a consistent positive G-gap > +0.5 and a consistent negative G-gap > -0.5 over a minimum of 2 estimations. Age, gender, race and BMI were collected from patients in this study. Blood samples were also 3 collected to measure FN3K activity, protein levels, and markers of CVD in relation to G-gap. The second study involved 23 AECOPD patients who were recruited from St George’s Hospital (London) and were treated with either metformin or a placebo. Serum samples were collected from these patients for a larger study: we assayed those 23 serum samples for FN3K protein levels to explore any possible correlation between FN3K with metformin therapy in COPD patients. The third study utilised 36 human peripheral lung samples from healthy individuals, asymptomatic smokers and stable COPD patients (GOLD 2) who were recruited at The Section of Respiratory Medicine, University Hospital of Ferrara, Italy. Those samples were assessed for FN3K expression by means of immunohistochemistry to explore the difference in FN3K activity between those three categories. It was found that the intracellular activity and protein expression of the FN3K enzyme in diabetic patients negatively correlated with the values of G-gaps where FN3K activity was high in patients with negative G-gap. FN3K serum protein levels were shown to be enhanced with metformin administration in COPD diabetic patients, suggesting a protective role for FN3K enzyme against protein damaged caused by the non-enzymatic glycation of proteins. Therefore, patients with positive G-gap have lower FN3K activity than those with negative G-gap, and in turn they are more susceptible to diabetes related complications. Our data also indicate that metformin has a beneficial effect in reducing damage caused by carbonyl stress from cigarette smoking in COPD patients by the action of FN3K. Our research has demonstrated that FN3K contributes to the protein repair system which protects against damage caused by non-enzymatic glycation. The high activity for the FN3K enzyme was associated with low levels of AGEs and low carbonyl stress levels in observed among patients with diabetes and COPD. In contrast, COPD patients tend to have low FN3K-mediated protection against protein damage in comparison to the normal population. These patients tend to be at risk for developing more complications, particularly CVD complications, than normal, healthy individuals. Treatment with metformin enhances FN3K action in COPD diabetic patients, possibly as a protective enzyme against the damaged caused by the non-enzymatic glycation.

La metformine est utilisée chez les patients et patientes atteints du diabète de type II. Elle est également administrée lors d’une infertilité liée à une insulino-résistance ou à un désordre métabolique. Mon projet de recherche a été d’analyser les effets de cet antidiabétique sur la fonction gonadique administré au stade foetal ou à la puberté. Nous avons montré par une approche in vivo sur deux modèles animaux: 1) qu'une administration orale de metformine à des poulets pré-pubères entraine un retard de puberté. Il se caractérise par une réduction du poids testiculaire, du diamètre des tubes séminifères et par une baisse de la testostérone sérique. 2) qu’une exposition des foetus mâles à de la metformine, chez la souris, conduit une fois adulte a une diminution de la taille des portées de 30%. Ce dysfonctionnement est associé à des marques épigénétiques sur l’ADN et des anomalies morphologiques de la tête des spermatozoïdes. Des techniques à haut débit (protéomique et métabolomique) réalisées sur des cultures de cellules de Sertoli immatures traitées ou non à la metformine ont permis de démontrer : 1) que le traitement mène à un métabolisme cellulaire de type Warburglike. 2) que des protéines présentent des différences d’abondance entre les deux conditions et qu’elles sont impliquées dans l’organisation du cytosquelette, de l’adhésion cellulaire, de la compaction de l’ADN, de la régulation de la réponse cellulaire à l’hypoxie et de l’immunité. Les résultats obtenus suggèrent que les grandes fonctions de sécrétion, de support et de protection des cellules de Sertoli sont modifiées par cet antidiabétique et qu’une exposition in utero à la metformine pourrait agir sur la fertilité et sur le métabolisme. / Metformin is used to treat patients with type II diabetes, it could be also administered to improve infertility associated to insulin-resistance or metabolic disorder. My research project was to analyse the consequence of a metformin exposure on gonad function from fetal to adult period. We showed by an in vivo approach on two animal models: 1) that oral administration of metformin to young chickens delay the puberty. It is characterized by a reduction in the testis weight, diameter of seminiferous tubule and decrease in testosterone level. 2) that mice, exposed in utero with metformin leads at adulte age to a lower fertility. This dysfunction is associated with morphological abnormalities of the sperm head and epigenetic marks on DNA. The second approach used proteomic and metabolomic strategy on cultured Sertoli cells treated or not with metformin. We demonstrated : 1) that the treatment leads to Warburg-like cellular metabolism. 2) that proteins present differences of abundances are involved in cytoskeleton organization, cell adhesion, DNA compaction, reponsiveness to hypoxia and immunity. The results suggest that the main function of secretion, support and protection of germ cell by Sertoli cells are modified by this antidiabetic, and that in utero exposure to metformin could act on the fertility and metabolism.