Search

Numerous therapeutic options are available for Luminal, HER2-enriched and Normal-like breast cancers. However, only chemotherapy can be used for triple-negative breast cancers. Moreover, regardless of breast cancer subtypes, there are many cases of absence of responsiveness and treatment resistances. In some cases, resistance comes from the presence of cancer stem cells (CSC) within the tumor. A possible therapeutic approach consists of targeting the energy metabolism often modified in cancer cells and CSC. Thiazolidinediones (TZD) are studied in this context since they display an anticancer activity and can induce alterations of the energy metabolism. Our laboratory studies troglitazone (TGZ) from which we could obtain several derivatives displaying a higher efficiency and a lower toxicity towards human hepatocytes. Desulfurylated derivatives of TGZ have been synthetized recently. First we performed a structure-activity relationship study in order to determine the impact of the sulfur atom on the anticancer activity. We observed that desulfurylated derivatives of TGZ displayed a higher efficiency towards breast cancer cells. and the most active compound was EP13, one of the desulfurylated TDZ derivatives, on breast cancer cells. The most active compound, EP13, combined different potentiating chemical modifications and the removal of the sulfur moiety from the TZD cycle. Unlike TGZ, EP13 induces apoptosis of MDA-MB-231 cells. Then we showed that EP13 disrupted energy metabolism of MDA-MB-231 cells by inducing alteration of mitochondrial respiratory chain function, associated with reactive oxygen species (ROS) production in MDA-MB-231 cells. A glycolysis stimulation seems to compensate secondarily the mitochondrial respiration alteration. EP13 at low doses was able to potentiate doxorubicin and 5-fluorouracil actions on MDA-MB-231 cells. Finally, we established a 3D cell culture model, which could allow enrichment in CSC. EP13 could alter the establishment of mammospheres from MDA-MB-231 and MCF-7 cells. This work suggests a potential interest of EP13 for the development of therapeutic strategies targeting energy metabolism. It remains to establish if there is a link between modifications of energy metabolism and EP13-induced apoptosis and to use the mammosphere experimental model to determine if EP13 can affect breast CSC.; De nombreuses options thérapeutiques existent pour les cancers du sein luminaux, HER2 et normal like. En revanche, seule la chimiothérapie est utilisée pour les cancers du sein triple-négatifs. Par ailleurs, quels que soient les sous-types de cancer du sein, il existe des cas d’absence de réponse et des phénomènes de résistance aux traitements. Ces derniers peuvent être associés à la présence de cellules souches cancéreuses (CSC) au sein des tumeurs. Une des pistes thérapeutiques est de cibler le métabolisme énergétique souvent modifié dans les cellules cancéreuses et les CSC. Les thiazolidinediones (TZD) sont étudiées dans ce contexte car elles présentent une action anticancéreuse pouvant résulter d’une altération du métabolisme énergétique. Notre laboratoire s’intéresse à la troglitazone (TGZ) dont plusieurs dérivés présentent une efficacité accrue et une toxicité réduite envers les hépatocytes. Des dérivés désoufrés de la TGZ ont récemment été synthétisés. Nous avons d’abord réalisé une étude des relations structure activité afin d’évaluer l’importance du soufre dans l’action anticancéreuse. Nous avons montré que la suppression du soufre au niveau du cycle TZD améliore l’efficacité anticancéreuse des composés sur des lignées de cellules cancéreuses mammaires. Le dérivé le plus actif est EP13, composé qui combine différentes modifications chimiques potentialisatrices et l’absence de soufre. Il induit l’apoptose des cellules MDA-MB-231. Puis, nous avons étudié l’effet d’EP13 sur le métabolisme énergétique des cellules MDA-MB-231. Il induit une altération du fonctionnement de la chaîne respiratoire associée à la production d’espèces réactives de l’oxygène (ERO) dans les cellules MDA-MB-231. Une stimulation de la glycolyse permet de compenser l’altération de la respiration mitochondriale. De faibles concentrations d’EP13 potentialisent l’action de la doxorubicine et du 5-fluorouracile dans les cellules MDA-MB-231. Enfin nous avons établi un modèle de culture cellulaire 3D (mammosphères), qui permettrait un enrichissement en CSC. EP13 est capable d’affecter les mammosphères constituées à partir de cellules MDA-MB-231 et MCF-7. EP13 se présente comme un candidat potentiel pour des stratégies thérapeutiques visant à cibler le métabolisme énergétique. Il reste à déterminer s’il existe un lien entre la modification du métabolisme énergétique et l’effet anti-cancéreux et à exploiter le modèle des mammosphères pour déterminer si EP13 affecte aussi les CSC.

Lifestyle modifications, especially weight loss, are efficient on NASH liver injury, however rarely followed in clinical practice. The target population of pharmacologic treatments is represented by patients with NASH and fibrosis. Out of histological improvement, efficacy of treatments should be assessed through liver morbi-mortality benefit, but also on extrahepatic events, such as cardiovascular. Among anti-diabetic treatments, glitazones et GLP-1 agonists have shown efficacy on histological liver injury. Vitamin E is efficient on liver injury but at the cost of prostate cancer and stroke over risk. About 60 new molecules are under investigation in NASH and have 4 different types of mechanism of action: metabolic, oxidative stress/apoptosis, anti inflammatory and anti fibrotic. A phase 3 trial evaluating obeticholic acid have shown a 72 weeks duration treatment improved significantly fibrosis.

A major challenge in oncology is the treatment of triple-negative breast cancer (ER-, PR-, HER2-) as no targeted therapy are available. These tumors present often a chemotherapy resistance and a higher relapse incidence. 78% of them do not express claudin 1 and display a poor prognosis. Claudin 1 is involved in cell-cell adhesion and may be a tumor suppressor gene in breast cancer. In this context, we study if claudin 1 re-expression could be a possible approach. In the laboratory, we developed derivatives thaziolidinediones (TZD) compounds, which increase claudin 1 expression and lead to apoptosis of breast cancer cells. The goals of my thesis is 1) to characterize the involvement of claudin 1 in their pro-apoptotic effect 2) to study their mechanism of action 3) to determine if claudin 1 could sensitize the TNBC cells to the chemotherapy agents. During my thesis, we showed that claudin 1 overexpression and the compound Δ2-TGZ induce apoptosis of TNBC « claudin 1-low » MDA-MB-231 and Hs578T cells. Claudin 1 is involved in the pro-apoptotic effect of Δ2-TGZ in MDA-MB-231 cells. Then, we demonstrated that Δ2-TGZ and AB186 lead to early action through a modification of cell morphology followed an expression of claudin 1 at the membrane and an inhibition of cell migration before the apoptosis process. In addition, claudin 1 overexpression decreases the cell migration through the loss of stress fibers and the formation of cell junctions. We showed that claudin 1 overexpression potentialize the pro-apoptotic effect of Δ2-TGZ in MDA-MB-231 cells. Finally, we observed that claudin 1 sensitize the MDA-MB-231 cells to 5-FU. In fine, our data allowed a better understanding of Δ2-TGZ and AB186 mechanism of action and identification of claudin 1 as a promising target in TNBC « claudin 1-low »; Un défi majeur en cancérologie est le traitement des tumeurs mammaires dites triple-négatives (ER-, PR-, HER2-). Elles sont le plus souvent résistantes aux traitements conventionnels et présentent un haut risque de récidive. De plus, l’absence de cibles thérapeutiques ne permet pas le développement de thérapie spécifique. 78% de ces tumeurs expriment faiblement la claudine 1 et sont de très mauvais pronostic. Cette protéine est impliquée dans l'adhérence des cellules entre elles et pourrait jouer un rôle suppresseur de tumeur dans les cancers mammaires. Dans ce contexte, nous étudions si sa réexpression pourrait être une piste de traitement. Au laboratoire, nous avons développé des dérivés de la famille des thiazolidinediones (TZD) qui stimulent l’expression de la claudine 1 et induisent l’apoptose des cellules cancéreuses mammaires. Les objectifs de ma thèse ont consisté 1) à déterminer l’implication de la claudine 1 dans l’effet pro-apoptotique de ces composés 2) à l’étude de leurs mécanismes d’action 3) évaluer si l’expression de la claudine 1 pourrait sensibiliser les cellules cancéreuses triple-négatives aux agents de chimiothérapie. Au cours de cette thèse, nous avons montré que la surexpression de la claudine 1 et le composé Δ2-TGZ induisent l’apoptose des cellules triple-négatives « claudin 1-low » MDA-MB-231 et Hs578T. De plus, la claudine 1 est impliquée dans l’effet pro-apoptotique de la Δ2-TGZ dans les cellules MDA-MB-231. Par ailleurs, nous avons démontré que les dérivés TGZ, la Δ2-TGZ et l’AB186, agissent de manière précoce en modifiant la morphologie des cellules suivie d’une réexpression de la claudine 1 membranaire et d’une inhibition de la migration cellulaire avant même d’induire la mort cellulaire par apoptose. De plus, la surexpression de la claudine 1 inhibe la migration cellulaire associée à la perte des fibres de stress et la formation des jonctions intercellulaires. Nous avons également montré que la réexpression de la claudine 1 sensibilise les cellules MDA-MB-231 à l’agent de chimiothérapie, le 5-FU. L’ensemble des résultats de thèse a permis de mieux comprendre le mécanisme d’action de la Δ2-TGZ et de l’AB186 sur les cellules cancéreuses mammaires mais aussi d’identifier la claudine 1 comme cible potentielle prometteuse dans les cellules triple-négatives « claudin 1-low »

A major challenge in oncology is the treatment of triple-negative breast cancer (ER-, PR-, HER2-) as no targeted therapy are available. These tumors present often a chemotherapy resistance and a higher relapse incidence. 78% of them do not express claudin 1 and display a poor prognosis. Claudin 1 is involved in cell-cell adhesion and may be a tumor suppressor gene in breast cancer. In this context, we study if claudin 1 re-expression could be a possible approach. In the laboratory, we developed derivatives thaziolidinediones (TZD) compounds, which increase claudin 1 expression and lead to apoptosis of breast cancer cells. The goals of my thesis is 1) to characterize the involvement of claudin 1 in their pro-apoptotic effect 2) to study their mechanism of action 3) to determine if claudin 1 could sensitize the TNBC cells to the chemotherapy agents. During my thesis, we showed that claudin 1 overexpression and the compound Δ2-TGZ induce apoptosis of TNBC « claudin 1-low » MDA-MB-231 and Hs578T cells. Claudin 1 is involved in the pro-apoptotic effect of Δ2-TGZ in MDA-MB-231 cells. Then, we demonstrated that Δ2-TGZ and AB186 lead to early action through a modification of cell morphology followed an expression of claudin 1 at the membrane and an inhibition of cell migration before the apoptosis process. In addition, claudin 1 overexpression decreases the cell migration through the loss of stress fibers and the formation of cell junctions. We showed that claudin 1 overexpression potentialize the pro-apoptotic effect of Δ2-TGZ in MDA-MB-231 cells. Finally, we observed that claudin 1 sensitize the MDA-MB-231 cells to 5-FU. In fine, our data allowed a better understanding of Δ2-TGZ and AB186 mechanism of action and identification of claudin 1 as a promising target in TNBC « claudin 1-low », Un défi majeur en cancérologie est le traitement des tumeurs mammaires dites triple-négatives (ER-, PR-, HER2-). Elles sont le plus souvent résistantes aux traitements conventionnels et présentent un haut risque de récidive. De plus, l’absence de cibles thérapeutiques ne permet pas le développement de thérapie spécifique. 78% de ces tumeurs expriment faiblement la claudine 1 et sont de très mauvais pronostic. Cette protéine est impliquée dans l'adhérence des cellules entre elles et pourrait jouer un rôle suppresseur de tumeur dans les cancers mammaires. Dans ce contexte, nous étudions si sa réexpression pourrait être une piste de traitement. Au laboratoire, nous avons développé des dérivés de la famille des thiazolidinediones (TZD) qui stimulent l’expression de la claudine 1 et induisent l’apoptose des cellules cancéreuses mammaires. Les objectifs de ma thèse ont consisté 1) à déterminer l’implication de la claudine 1 dans l’effet pro-apoptotique de ces composés 2) à l’étude de leurs mécanismes d’action 3) évaluer si l’expression de la claudine 1 pourrait sensibiliser les cellules cancéreuses triple-négatives aux agents de chimiothérapie. Au cours de cette thèse, nous avons montré que la surexpression de la claudine 1 et le composé Δ2-TGZ induisent l’apoptose des cellules triple-négatives « claudin 1-low » MDA-MB-231 et Hs578T. De plus, la claudine 1 est impliquée dans l’effet pro-apoptotique de la Δ2-TGZ dans les cellules MDA-MB-231. Par ailleurs, nous avons démontré que les dérivés TGZ, la Δ2-TGZ et l’AB186, agissent de manière précoce en modifiant la morphologie des cellules suivie d’une réexpression de la claudine 1 membranaire et d’une inhibition de la migration cellulaire avant même d’induire la mort cellulaire par apoptose. De plus, la surexpression de la claudine 1 inhibe la migration cellulaire associée à la perte des fibres de stress et la formation des jonctions intercellulaires. Nous avons également montré que la réexpression de la claudine 1 sensibilise les cellules MDA-MB-231 à l’agent de chimiothérapie, le 5-FU. L’ensemble des résultats de thèse a permis de mieux comprendre le mécanisme d’action de la Δ2-TGZ et de l’AB186 sur les cellules cancéreuses mammaires mais aussi d’identifier la claudine 1 comme cible potentielle prometteuse dans les cellules triple-négatives « claudin 1-low »

The absence of response and the resistance of cancer cells to therapies are strong arguments for the development of new therapeutic strategies. Data from the literature suggest that it could be interesting to target energy metabolism of cancer cells. In this context, thiazolidinediones (TZDs) display antiproliferative effects that could be the result of energy metabolism alteration. During this PhD, we aimed at determining if Δ2-Troglitazone (Δ2-TGZ) could modify energy metabolism of breast cancer cells. The experiments performed previously used a culture medium containing 1% of fetal calf serum (FCS) that is rather a stress inducing condition that can disturb cell metabolism. Thus, we first characterized the effects of Δ2-TGZ in a 10% FCS containing medium. In this case, Δ2-TGZ still decreases cell proliferation of breast cancer cells, but it requires high doses. Besides, Δ2-TGZ induces cell cycle arrest instead of apoptosis. Then, we have shown that Δ2-TGZ induced modifications of energy metabolism, which are due to a decrease in oxidative phosphorylation. We also observed an increase in glycolytic activity that is probably a compensatory mechanism. During this part of our work, we have also characterized the mechanisms involved in the anticancer activity of 2-deoxyglucose. We have shown that in breast cancer cells, this compound acts not only by glycolysis inhibition but also by protein N-glycosylation alteration. We have now to determine the part of metabolic alterations that are involved in the anti-cancer effects of Δ2-TGZ; L’absence de réponse et la résistance des cellules cancéreuses mammaires aux thérapies actuelles justifient de développer de nouveaux traitements. Une stratégie prometteuse consiste à cibler le métabolisme énergétique des cellules cancéreuses. Dans ce contexte, des thiazolidinediones (TZD) présentent des effets antiprolifératifs qui pourraient résulter d’une atteinte du métabolisme énergétique. Notre laboratoire étudie des TZD dérivées de la troglitazone (TGZ). Durant cette thèse, nous avons cherché à déterminer si la Δ2-Troglitazone (Δ2-TGZ) modifie le métabolisme énergétique des cellules cancéreuses mammaires. Jusqu’à présent, les expériences menées au laboratoire étaient réalisées dans un milieu de culture contenant 1% de sérum de veau fœtal (SVF) qui crée un stress peu propice à l’étude du métabolisme. Nous avons donc d’abord caractérisé les effets de la Δ2-TGZ dans un milieu de culture contenant 10% SVF. Dans ces conditions, la Δ2-TGZ diminue toujours la prolifération des cellules cancéreuses mammaires, mais les doses requises sont plus élevées. En outre, la Δ2-TGZ induit des effets cytostatiques plutôt que l’apoptose. Nous avons ensuite montré que la Δ2-TGZ induit une perturbation du métabolisme énergétique, consistant en un blocage de la respiration mitochondriale que les cellules semblent compenser en stimulant la glycolyse. En parallèle, nous avons caractérisé le mode d’action du 2-désoxyglucose dont l’action antiproliférative dans les cellules cancéreuses mammaires est due à l’inhibition de la glycolyse et à la perturbation de la N-glycosylation des protéines. Il reste à déterminer la part des altérations métaboliques dans l’action anti-cancéreuse de la Δ2-TGZ

The absence of response and the resistance of cancer cells to therapies are strong arguments for the development of new therapeutic strategies. Data from the literature suggest that it could be interesting to target energy metabolism of cancer cells. In this context, thiazolidinediones (TZDs) display antiproliferative effects that could be the result of energy metabolism alteration. During this PhD, we aimed at determining if Δ2-Troglitazone (Δ2-TGZ) could modify energy metabolism of breast cancer cells. The experiments performed previously used a culture medium containing 1% of fetal calf serum (FCS) that is rather a stress inducing condition that can disturb cell metabolism. Thus, we first characterized the effects of Δ2-TGZ in a 10% FCS containing medium. In this case, Δ2-TGZ still decreases cell proliferation of breast cancer cells, but it requires high doses. Besides, Δ2-TGZ induces cell cycle arrest instead of apoptosis. Then, we have shown that Δ2-TGZ induced modifications of energy metabolism, which are due to a decrease in oxidative phosphorylation. We also observed an increase in glycolytic activity that is probably a compensatory mechanism. During this part of our work, we have also characterized the mechanisms involved in the anticancer activity of 2-deoxyglucose. We have shown that in breast cancer cells, this compound acts not only by glycolysis inhibition but also by protein N-glycosylation alteration. We have now to determine the part of metabolic alterations that are involved in the anti-cancer effects of Δ2-TGZ, L’absence de réponse et la résistance des cellules cancéreuses mammaires aux thérapies actuelles justifient de développer de nouveaux traitements. Une stratégie prometteuse consiste à cibler le métabolisme énergétique des cellules cancéreuses. Dans ce contexte, des thiazolidinediones (TZD) présentent des effets antiprolifératifs qui pourraient résulter d’une atteinte du métabolisme énergétique. Notre laboratoire étudie des TZD dérivées de la troglitazone (TGZ). Durant cette thèse, nous avons cherché à déterminer si la Δ2-Troglitazone (Δ2-TGZ) modifie le métabolisme énergétique des cellules cancéreuses mammaires. Jusqu’à présent, les expériences menées au laboratoire étaient réalisées dans un milieu de culture contenant 1% de sérum de veau fœtal (SVF) qui crée un stress peu propice à l’étude du métabolisme. Nous avons donc d’abord caractérisé les effets de la Δ2-TGZ dans un milieu de culture contenant 10% SVF. Dans ces conditions, la Δ2-TGZ diminue toujours la prolifération des cellules cancéreuses mammaires, mais les doses requises sont plus élevées. En outre, la Δ2-TGZ induit des effets cytostatiques plutôt que l’apoptose. Nous avons ensuite montré que la Δ2-TGZ induit une perturbation du métabolisme énergétique, consistant en un blocage de la respiration mitochondriale que les cellules semblent compenser en stimulant la glycolyse. En parallèle, nous avons caractérisé le mode d’action du 2-désoxyglucose dont l’action antiproliférative dans les cellules cancéreuses mammaires est due à l’inhibition de la glycolyse et à la perturbation de la N-glycosylation des protéines. Il reste à déterminer la part des altérations métaboliques dans l’action anti-cancéreuse de la Δ2-TGZ

National audience; Le cancer du sein est un problème majeur de santé publique. En France, il représente la première cause de décès par cancer chez la femme. L'existence de tumeurs mammaires qui ne répondent pas aux traitements ou qui acquièrent une résistance, justifie le développement de nouveaux composés à action anticancéreuse. Une stratégie en pleine expansion est de "repositionner" d’anciennes molécules déjà utilisées cliniquement pour de nouveaux usages thérapeutiques. Notre équipe travaille depuis plusieurs années sur le repositionnement de la troglitazone (TGZ), un agoniste synthétique du récepteur PPARgamma initialement utilisé comme antidiabétique mais qui présentait aussi des effets anticancéreux décrits dès les années 90. Cet antidiabétique a dû être retiré du marché en raison de son hépato-toxicité. En tenant compte du mécanisme d’action de la TGZ, de sa métabolisation et des effets secondaires sur les hépatocytes, nous avons développé et breveté de nouveaux composés. Ces dérivés insaturés n’activent plus PPARgamma, ils ont une activité anticancéreuse accrue et sont moins toxiques pour les hépatocytes humains. Nos recherches actuelles sont dédiées à la compréhension du mécanisme d’action de ces dérivés. Nous nous focalisons sur l’atteinte du métabolisme énergétique d’une part et la réexpression de la claudine 1, protéine des jonctions cellulaires, d’autre part. Des études in vivo sont en cours. L'utilisation de ces composés seuls ou en association avec d'autres agents anticancéreux pourrait constituer une piste thérapeutique novatrice pour les tumeurs triple-négatives, en particulier les tumeurs « claudin 1 low » qui sont de mauvais pronostic.

National audience; Malgré les sommes toujours plus colossales investies dans la recherche et le développement par les entreprises pharmaceutiques, peu de nouvelles entités moléculaires sont effectivement mises sur le marché. Il est ainsi nécessaire de développer des approches originales pour la découverte de nouvelles molécules actives. Parmi celles-ci, le «drug reprofiling» est une démarche intéressante. Elle consiste à identifier et à développer de nouveaux usages pour des médicaments existants. Par exemple, les molécules de la famille des glitazones qui sont utilisées pour le traitement du diabète ont montré une activité antiproliférative. L’effet anticancéreux a été confirmé par des méta-analyses dans des cohortes de patients diabétiques traités par ces composés, mais aussi en bithérapie avec des inhibiteurs de tyrosine kinase. En suivant cette démarche, nous avons développé des analogues de la troglitazone qui avait montré une activité antiproliférative sur diverses lignées de cellules cancéreuses. Nous avons optimisé sa structure de façon à 1) augmenter son activité antiproliférative et 2) diminuer sa toxicité envers les cellules non cancéreuses et 3) augmenter sa stabilité métabolique. En effet, les molécules obtenues ont montré une activité de l’ordre du micromolaire sur diverses lignées cellulaires cancéreuses alors que des hépatocytes non cancéreux y sont complètement insensibles. Corrélativement, la demi-vie (t½) du composé leader est nettement supérieure à celle du composé parent après administration par voie iv à des souris.

Management of type 1 diabetes essentially relies upon intensive insulin therapy adjusted according to careful home blood glucose monitoring. The potential role of oral antidiabetic agents is controversial and what so ever is limited in type 1 diabetes. Nevertheless, metformin may still be useful in the presence of obesity and/or insulin resistance while acarbose could reduce the amplitude of glycaemic fluetuations, namely postprandial hyperglycaemia and late postmeal glycaemic nadir. Both drugs may also minimize weight gain that results from intensive insulin therapy. Finally, inhibitors of dipeptidyl peptidase-4 (glitpins), by inhibiting glucagon secretion, and inhibitors of renal SGLT2 cotransporters, thus promoting glucosuria independently of insulin, might also be beneficial in type 1 diabetes, although specific studies are still ongoing to verify this hypothesis.

One of the main goals of the anti-cancer research is to develop new therapeutic option for resistant tumor. In this context, the recent discovery of thiazolidinedione devoid of PPARγ activity with a strong anti-cancer effect opens new perspectives. In a previous study, the laboratory showed that an inactive derivative of PPARγ, the Δ2-TGZ, induce a proteasome-dependent degradation of estrogen receptor α in PPARγ-independent way. Thus, during my thesis we aimed 1) to participate in the study of new compounds less toxic and more effective to inhibit the proliferation of mammary cancer cells, 2) to better understand PPARγ-independent mechanisms involved in the anti-cancer effect of the TZD. In the present work, we characterise new compounds more effective than Δ2-TGZ to inhibit the proliferation of the breast cancer cells MCF-7 and MDA-MB-231 and are less toxic on primary culture of human hepatocytes. We pursued the study on mechanisms involved in PPARγ-independent antiproliferative activity of Δ2-TGZ. We showed that Δ2-TGZ is able to induce endoplasmic reticulum stress as soon as 3 hours and apoptosis in later times 48 hours of treatment. Nevertheless we could not conclude of the existence of a link between these two pathways. Finally, we studied the effect of the biotinylation of a natural ligand of PPARγ: the 15d-PGJ2. This modification drive to an increased effect of the 15d-PGJ2 on the anti-proliferative effect of breast cancer cells, reticulum endoplasmic stress and death by apoptosis. These effects are partially PPARγ-dependent for reticulum endoplasmic stress and only PPARγ-independent for apoptosis. This work highlighted new promising tools of breast cancers treatment., L'un des enjeux majeurs de la recherche anti-cancéreuse est de développer de nouvelles thérapies en direction des tumeurs réfractaires aux traitements conventionnels. Dans ce contexte, l'identification récente de l'activité anti-tumorale PPARγ-indépendante des thiazolidinediones ouvre de nouvelles perspectives thérapeutiques. Au sein du laboratoire, il a été montré qu'un analogue inactif de la TGZ, la Δ2-TGZ, induit une dégradation protéasome-dépendante du récepteur α aux oestrogènes de manière PPARγ-indépendante. A partir de ces données, les objectifs de ma thèse ont été 1) de participer à la caractérisation de nouveaux composés à activité anti-cancéreuse 2) de mieux comprendre les mécanismes PPARγ-indépendants mis en jeu dans l'effet anti-cancéreux des TZD. Lors de ce travail de thèse, nous avons caractérisé de nouveaux composés plus efficaces que la Δ2- TGZ pour l'inhibition de la prolifération des cellules cancéreuses mammaires MCF-7 et MDA-MB-231 et faiblement toxiques sur des cultures primaires d'hépatocytes humains. De plus, nous avons montré que la Δ2-TGZ est capable d'induire un stress du réticulum endoplasmique à des temps précoces dès 3 heures et une apoptose à des temps plus tardifs 48 heures. Cependant, nous n'avons pas pu conclure à l'existence d'un lien entre les deux mécanismes. Enfin, nous avons montré que la biotinylation d'un ligand naturel de PPARγ, la 15d-PGJ2, accroît son effet anti-prolifératif sur les cellules cancéreuses mammaires MCF-7 et MDA-MB-231 et conduit à un stress du réticulum endoplasmique et à une mort par apoptose. Ces effets sont partiellement dépendants de PPARγ pour le stress du réticulum endoplasmique mais strictement PPARγ-indépendants pour l'apoptose. Ce travail pourrait permettre de constituer de nouveaux outils thérapeutiques dans le traitement du cancer du sein.

The ligands of PPARγ nuclear receptors (15-deoxy-D12,14-Prostaglandin J2 (15d-PGJ2) andthiazolidinediones (TZDs) : troglitazone (TGZ), ciglitazone (CGZ)) show antiproliferative effects onbreast cancer cell lines. Several studies suggest that the anti-cancer effects are PPARγ-independent.Our work is focused on the comprehension of such mechanisms of action.Our study has shown the induction of the transcription factor EGR1 (Early Growth Response gene 1)by some PPARγ ligands (TGZ, CGZ, 15d-PGJ2, and D2-TGZ (PPARg inactive agonist)) in thehormone-dependent breast cancer cells MCF7. This early effect is PPARγ-independent. It is associatedwith the almost immediate release of intracellular calcium followed by the activation of ERK1/2.EGR1 induction also occurs in the hormone-independent breast cancer cells MDA-MB-231 treatedwith D2-TGZ. However, EGR1 induction plays only a partial role in the antiproliferative effect.Data analysis of DNA array has suggested the induction of an endoplasmic reticulum stress (ER) inMCF7 cells treated with D2-TGZ. Complementary data have confirmed this result in MCF7 cells andin MDA-MB-231 cells. However, the role of ER stress in the antiproliferative effect is still to bedetermined.Finally, we have tested the hypothesis of a link between EGR1 and ER stress. Indeed, EGR1 is alsoearly induced by other ER stress inductors. Diverse conditions where EGR1 is inhibited suggest apossible regulation of ATF3 expression by EGR1., Les ligands des récepteurs nucléaires PPARγ (15-deoxy-D12,14-Prostaglandine J2 (15d-PGJ2) et lesthiazolidinediones (TZDs) : troglitazone (TGZ), ciglitazone (CGZ)) exercent un effet antiprolifératifsur les lignées cancéreuses mammaires. Plusieurs études suggèrent que les effets anticancéreux sontliés à des effets PPARγ-indépendants. Notre travail s’inscrit dans la compréhension de telsmécanismes d’action.Notre étude a montré une induction du facteur de transcription EGR1 (Early Growth Response gene 1)par certains ligands de PPARγ (TGZ, CGZ, 15d-PGJ2 et D2-TGZ (agoniste inactif de PPARg)) dansles cellules cancéreuses mammaires hormono-dépendantes MCF7. Cet effet est précoce et PPARγ-indépendant. Il est lié à une libération quasi immédiate de calcium intracellulaire suivie de l’activationdes ERK1/2. L’induction d’EGR1 a aussi lieu dans les cellules hormono-indépendantes MDA-MB-231 exposées à la D2-TGZ. Cependant, l’induction d’EGR1 ne joue qu’un rôle partiel dans l’effetantiprolifératif.Les données d’une analyse par puce à ADN ont suggéré l’induction d’un stress du réticulumendoplasmique (RE) dans les cellules MCF7 exposées à la D2-TGZ. Des analyses complémentairesont confirmé que la D2-TGZ induit un tel stress dans les cellules MCF7 et MDA-MB-231. Cependant,le rôle du stress du RE dans l’effet antiprolifératif de la D2-TGZ reste à déterminer.Nous avons enfin testé l’hypothèse d’un lien entre EGR1 et stress du RE. En effet, EGR1 est aussiinduit précocement par d’autres inducteurs de stress du RE. Les diverses situations où l’inductiond’EGR1 est inhibée suggèrent une régulation possible de l’expression du facteur de transcriptionATF3 par EGR1.

The ligands of PPARγ nuclear receptors (15-deoxy-D12,14-Prostaglandin J2 (15d-PGJ2) andthiazolidinediones (TZDs) : troglitazone (TGZ), ciglitazone (CGZ)) show antiproliferative effects onbreast cancer cell lines. Several studies suggest that the anti-cancer effects are PPARγ-independent.Our work is focused on the comprehension of such mechanisms of action.Our study has shown the induction of the transcription factor EGR1 (Early Growth Response gene 1)by some PPARγ ligands (TGZ, CGZ, 15d-PGJ2, and D2-TGZ (PPARg inactive agonist)) in thehormone-dependent breast cancer cells MCF7. This early effect is PPARγ-independent. It is associatedwith the almost immediate release of intracellular calcium followed by the activation of ERK1/2.EGR1 induction also occurs in the hormone-independent breast cancer cells MDA-MB-231 treatedwith D2-TGZ. However, EGR1 induction plays only a partial role in the antiproliferative effect.Data analysis of DNA array has suggested the induction of an endoplasmic reticulum stress (ER) inMCF7 cells treated with D2-TGZ. Complementary data have confirmed this result in MCF7 cells andin MDA-MB-231 cells. However, the role of ER stress in the antiproliferative effect is still to bedetermined.Finally, we have tested the hypothesis of a link between EGR1 and ER stress. Indeed, EGR1 is alsoearly induced by other ER stress inductors. Diverse conditions where EGR1 is inhibited suggest apossible regulation of ATF3 expression by EGR1.; Les ligands des récepteurs nucléaires PPARγ (15-deoxy-D12,14-Prostaglandine J2 (15d-PGJ2) et lesthiazolidinediones (TZDs) : troglitazone (TGZ), ciglitazone (CGZ)) exercent un effet antiprolifératifsur les lignées cancéreuses mammaires. Plusieurs études suggèrent que les effets anticancéreux sontliés à des effets PPARγ-indépendants. Notre travail s’inscrit dans la compréhension de telsmécanismes d’action.Notre étude a montré une induction du facteur de transcription EGR1 (Early Growth Response gene 1)par certains ligands de PPARγ (TGZ, CGZ, 15d-PGJ2 et D2-TGZ (agoniste inactif de PPARg)) dansles cellules cancéreuses mammaires hormono-dépendantes MCF7. Cet effet est précoce et PPARγ-indépendant. Il est lié à une libération quasi immédiate de calcium intracellulaire suivie de l’activationdes ERK1/2. L’induction d’EGR1 a aussi lieu dans les cellules hormono-indépendantes MDA-MB-231 exposées à la D2-TGZ. Cependant, l’induction d’EGR1 ne joue qu’un rôle partiel dans l’effetantiprolifératif.Les données d’une analyse par puce à ADN ont suggéré l’induction d’un stress du réticulumendoplasmique (RE) dans les cellules MCF7 exposées à la D2-TGZ. Des analyses complémentairesont confirmé que la D2-TGZ induit un tel stress dans les cellules MCF7 et MDA-MB-231. Cependant,le rôle du stress du RE dans l’effet antiprolifératif de la D2-TGZ reste à déterminer.Nous avons enfin testé l’hypothèse d’un lien entre EGR1 et stress du RE. En effet, EGR1 est aussiinduit précocement par d’autres inducteurs de stress du RE. Les diverses situations où l’inductiond’EGR1 est inhibée suggèrent une régulation possible de l’expression du facteur de transcriptionATF3 par EGR1.

The European Medicines Agency (EMA) recommended the suspension of the marketing authorisations for sibutramine, a centrally-acting anti-obesity agent, and of rosiglitazone, an oral glucose-lowering compound of the thiazolidinedione family. This decision was taken because of a possible increased cardiovascular risk, mainly ischaemic heart disease, associated with the use of sibutramine or rosiglitazone in patients with pathologies prone to develop cardiovascular complications. The conclusion was that the benefits no longer outweigh the risks. The present paper summarizes the up- and -down history of these two pharmacological compounds, analyzes the data that resulted in such a decision and briefly discusses the future implications regarding the pharmacotherapy of cardiometabolic diseases.

A 61-year-old woman is referred for bilateral diabetic macular edema. Her visual acuity is 20/70 in the right eye and 20/50 in the left eye. She presents a macular edema on both eyes. Her diabetes and her blood pressure are well controlled. We note that the decrease in visual acuity occured when the patient began taking rosiglitazone (Avandia) 4 mg per day. Three months after replacing rosiglitazone by gliclazide (Diamicron), the visual acuity of the patient improves to 20/40 in the right eye and 20/30 in the left eye.

The insulin-sensitizing thiazolidinediones are effective drugs to achieve glycemic control in patients with type 2 diabetes. Results from preclinical studies have demonstrated that activation of PPAR-gamma inhibits primarily bone formation by diverting mesenchymal stem cells to the adipocytic rather than to the osteogenic lineage. In humans studies demonstrated accelerated bone loss, impaired bone mineral density as well as an increased fracture risk for thiazolidinedione users, mostly for women. As a consequence of these observations, clinicians have to carefully assess the fracture risk in patients with type 2 diabetes before starting a therapy with thiazolidinediones.

International audience; Peroxisome proliferators activated receptors (PPAR) are ligand-inducible nuclear transacting factors comprising three subtypes, PPARα, PPARβ/δ and PPARγ, which play a key role in lipids and glucose homeostasis. All PPAR subtypes have been identified in joint or inflammatory cells and their activation resulted in a transcriptional repression of pro-inflammatory cytokines (IL-1, TNFα), early inflammatory genes (NOS2, COX-2, mPGES-1) or matrix metalloproteases (MMP-1, MMP-13), at least for the γ subtype. PPAR full agonists were also shown to stimulate IL-1 receptor antagonist (IL-1Ra) production by cytokine-stimulated articular cells in a subtype-dependent manner. These anti-inflammatory and anti-catabolic properties were confirmed in animal models of joint diseases where PPAR agonists reduced synovial inflammation while preventing cartilage destruction or inflammatory bone loss, although many effects required much higher doses than needed to restore insulin sensitivity or to lower circulating lipid levels. However, these promising effects of PPAR full agonists were hampered by their ability to reduce the growth factor-dependent synthesis of extracellular matrix components or to induce chondrocyte apoptosis, by the possible contribution of immunosuppressive properties to their anti-arthritic effects, by the increased adipocyte differentiation secondary to prolonged stimulation of PPARγ, and by a variable contribution of PPAR subtypes depending on the system. Clinical data are scarce in rheumatoid arthritis (RA) patients whereas thousands of patients worldwilde, treated with PPAR agonists for type 2 diabetes or dyslipidemia, are paradoxically prone to suffer from osteoarthritis (OA). Whereas high dosage of full agonists may expose RA patients to cardiovascular adverse effects, the proof of concept that PPAR agonists have therapeutical relevance to OA may benefit from an epidemiological follow-up of joint lesions in diabetic or hyperlipidemic patients treated for long periods of time with glitazones or fibrates. Additionally, cellular and animal studies are required to assess whether partial agonists of PPAR (SPPARMs) may preserve therapeutical properties with potentially less safety concern.; Les récepteurs activés par les proliférateurs de peroxysomes (PPAR) sont des facteurs de transcription inductibles par des ligands dont il existe trois sous-types, PPARα, PPARβ/δ et PPARγ jouant un rôle primordial dans le métabolisme des lipides et l'homéostasie du glucose. Ces trois sous-types sont également exprimés dans les cellules résidentes de l'articulation et celles de l'infiltrat inflammatoire, et leur activation réprime l'expression de cytokines pro-inflammatoires (IL-1, TNFα), de gènes précoces de l'inflammation (iNOS, COX-2, mPGES-1) ou de métalloprotéases matricielles (MMP-1, MMP-13), tout du moins pour le sous-type γ. Les agonistes de PPAR sont également capables de stimuler la production de l'antagoniste du récepteur à l'IL-1 (IL-1Ra) par les cellules articulaires soumises à un stimulus cytokinique. Ces potentialités anti-inflammatoires et anti-cataboliques ont été confirmées dans des modèles animaux d'arthropathie, dans lesquels les agonistes de PPAR diminuent l'inflammation synoviale et préviennent la destruction du cartilage ou la perte osseuse inflammatoire, même si les posologies requises sont très supérieures à celles permettant de normaliser les taux circulants de lipides ou de rétablir la sensibilité des tissus périphériques à l'insuline. Ces effets prometteurs des agonistes sont cependant pondérés par leur capacité à diminuer l'effet trophique des facteurs de croissance sur la biosynthèse des composants matriciels ou à provoquer une apoptose chondrocytaire, par leur effet immunosuppresseur responsable d'une surestimation des propriétés anti-inflammatoires dans les polyarthrites expérimentales, par le renforcement de la différenciation adipocytaire lors d'une stimulation prolongée de PPARγ, et par la contribution variable des sous-types selon le système expérimental. Les données cliniques restent anecdotiques dans la polyarthrite rhumatoïde alors que, paradoxalement, des milliers de patients qui sont traités quotidiennement par des agonistes de PPAR pour un diabète de type 2 ou une dyslipidémie, souffrent conjointement d'arthrose. Alors que les fortes posologies d'agonistes exposeraient les patients polyarthritiques à un risque important d'effets indésirables, notamment cardiovasculaires, la démonstration de l'intérêt des agonistes de PPAR dans l'arthrose pourrait être apportée par une étude épidémiologique de l'incidence ou de l'évolution de la maladie arthrosique chez les patients diabétiques et/ou dyslipidémiques traités par des glitazones ou des fibrates. Il sera également opportun d'étudier si des agonistes partiels de PPAR permettront de conserver certaines potentialités thérapeutiques tout en diminuant le risque d'effets indésirables.

In 2007, several international studies brought useful information for the daily work of internists in hospital settings. This summary is of course subjective but reflects the interests and questions of the chief residents of the Department of internal medicine who wrote this article like an original trip in medical literature. This trip will allow you to review some aspects of important fields such as heart failure, diabetes, endocarditis, COPD, and quality of care. Besides the growing diversity of the fields covered by internal medicine, these various topics underline also the uncertainty internists have to face in a practice directed towards evidence.

Treatment of type 2 diabetes (T2DM) is based on lifestyle changes and oral antidiabetic agents or insulin. The UKPDS study has confirmed metformin (Met) as the initial monotherapy. Accordingly, Met is widely regarded as the first drug of choice for most patients with T2DM. Safety and efficacy of sulphonylureas (SU) have been confirmed by several clinical trials. Recently, thiazolidinediones (TZD) have addressed some aspects of insulin-resistance that characterized several T2DM patients. However, SU and TZD are associated with various side effects that limit their use in many patients. New agents have been recently developed which potentiate the activity of the incretin (GLP1). GLP1, a gut hormone secreted in response to meal ingestion, is rapidly degraded by dipeptidylpeptidase-4 (DPP-4). GLP1 enhances insulin secretion and inhibits glucagon secretion in a glucose-dependent manner, delays gastric emptying and, in animal studies, preserves beta-cell mass by reducing apoptosis and stimulates of beta-cell proliferation. GLP1 levels are abnormally low in T2DM patients. Two classes of agents based on GLP1 have been launched: DPP-4 inhibitors and DPP-4 resistant GLP1 analogues. Randomized studies confirmed their efficacy to improve glycemic control in T2DM patients. Orally administered DPP-4 inhibitors reduce HbA1c by 0.5-1.1%, without hypoglycaemic events and no weight gain. The sub-cutaneous injected GLP1 analogues (exenatide and liraglutide) show larger reductions in HbA1c by 0.8-1.7% and weight loss but are associated with gastrointestinal side effects contributing to a significant treatment interruption. Several studies support the use of DPP-4 inhibitors in combination with Met as a promising second line treatment.

Type 2 diabetes is a complex disease characterized by a dual defect of insulin secretion and insulin sensitivity, which may vary from patient to patient, but also along the natural history of the disease in a particular patient. Besides the lifestyle changes, the treatment strategy comprises the administration of agents that promote insulin secretion and/or that improve insulin sensitivity. Drugs facilitating weight loss also improve glucose control by reducing insulin resistance. A global approach should be recommended to reduce the high cardiovascular risk of diabetic patients. The present article aims at summarizing our contribution to the development of drugs designed for the treatment of type 2 diabetes.

Cardiovascular diseases continue to be the main cause of death in most industrialized countries. Endothelial dysfunction, a systemic process, is the earliest known marker of atherosclerosis and has become a major focus in acute ischemic disorders. We are investigating the hypothesis that, in these diseases, microvascular and endothelial dysfunctions occur simultaneously and precede the onset of macrovascular disease. We studied, to our knowledge for the first time in the same subjects, microvascular and endothelial functions in 11 patients with type 2 diabetes. 36 metabolic syndrome patients (NCEP-ATPIII criteria) and 25 young obese women matched with healthy controls. Micro vascular morphology and hemodynamics were evaluated non-invasively by means of nailfold videocapillaroscopy. Red blood cell velocity (RBCV, mm/s) was measured at rest and after release from 60 s of arterial occlusion (RBCVmax, mm/s) at the finger base, along with the time to reach RBCVmax (TRBCVmax, s), by video analysis with Cap Image software. Venous occlusion plethysmography was performed after intra-arterial infusions of acetylcholine and sodium nitroprusside to assess endo thelial-dependent and -independent vasodilation, respectively. We found similar results in the three groups of subjects, namely a significant decrease in RBCVmax, an increase in TRBCVmax, and a decrease in endothelial-dependent vasodilation. These findings clearly demonstrate that the two dysfunctions occur simultaneously in these groups of patients. Several mechanisms which could impair micro vascular and endothelial functions are associated with insulin resistance, and drugs that act on insulin resistance might thus be beneficial. Metformin, given to 16 first-degree relatives of patients with type 2 diabetes mellitus, who had the metabolic syndrome and normal glucose tolerance (ADA criteria), improved endothelial-dependent vasodilation and microcirculatory function. Rosiglitazone, given to 18 patients with the metabolic syndrome, enhanced vascular responses by improving endothelial function and increasing adiponectin levels. Increased triglyceride storage is often associated with insulin resistance, contributing to free fatty acid (FFA) overexposure. The two drugs tested here stimulate AMP-activated protein kinase, which promotes FFA oxidation and thus reduces oxidative stress, and might therefore attenuate endothelial lipotoxicity. The results strongly suggest that targeting micro vascular and endothelial dysfunctions in patients with metabolic disorders might help to prevent cardiovascular events, and warrant long-term clinical trials.

The present article aims at summarizing the recent controversy about rosiglitazone (Avandia), an insulin sensitizer used as oral antidiabetic agent in the treatment of type 2 diabetes. We will present and briefly discuss 1) the results of the meta-analysis that raised suspicion about a possible excess of coronary complications with rosiglitazone; 2) the more favourable results of the large prospective clinical trial RECORD, but which are currently limited to an interim analysis; and 3) the reassuring data from several large US databases comparing the cardiovascular prognosis of type 2 diabetic patients treated with different antidiabetic drugs. We will conclude, referring to the recent position statement of the Advisory Committee of the Food and Drug Administration, by providing some practical recommendations.

In last few years, the topic of nuclear receptor has been developed in the field of hepatology allowing envisaging therapeutic strategies for the most frequent chronic liver diseases. Peroxysome proliferator-activated receptors (PPAR) contribute to wide physiological processes within the liver such as lipid/glucid metabolisms, inflammatory response, cell differenciation and cell cycle. In vitro experiments and animal studies showed that PPARalpha discloses anti-inflammatory property and PPARgamma discloses anti-inflammatory, antifibrogenic and antiproliferative properties in the liver. Main available agonists are fibrates (PPARalpha) used for 20 years in cases of lipid metabolism abnormalities and glitazones (PPARgamma) used since 2000 for type 2 diabetes. In terms of therapy, animal studies and human trials have been conducted in steatopathies. However, clinicians have to be aware of potential specific side effects related to glitazones especially on cardiovascular system.

The standard treatment of Cushing disease is surgery. Radiotherapy and steroïdogenesis inhibitors are second-line treatments. The new multi-ligand somatostatin analogs, such as SOM230, having a much higher affinity with several receptors of somatostatin (SSTR1,3, and 5) than octreotid (mostly a SSTR2 receptor) have been synthetized. Some studies have shown that SSTR5 is predominantly expressed in corticotroph pituitary adenomas and that SOM230 has more efficacy than octreotid in the treatment of Cushing disease. It has been suggested that the thiazolinidinediones, PPAR-gamma agonists, might also be useful in the treatment of this disease, but studies are still limited and give conflicting results. In a recent study conducted on dogs, Castillo et al have shown that the retinoïds give encouraging results and might open a new pathway in the treatment of Cushing disease. But further studies, especially on humans, are necessary before conclusions can be reached. Labeur and his team have contributed a study on the use of gamma-interferon on murine pituitary cells and on human and murine corticotroph pituitary adenoma cells, and they have evidenced a 20 to 60% decrease in the production of ACTH in 5 cases out of 7 in the tumoral cells treated--versus the non-treated ones. Eventually, Pivonello and his team have confirmed the D2 dopaminergic receptor expression in corticotroph pituitary cells, mainly in the intermediary zone. Thus they have suggested that the dopaminergic agonists--such as cabergoline-could be used in corticotroph pituitary adenomas derivated from the intermediary zone.

Specific treatment of age-related aortic wall arteriosclerosis and stiffening is lacking. As anti-inflammatory ligands for peroxisome proliferator-activated receptor-gamma have beneficial effects on the arterial wall in atherosclerosis, we investigated whether chronic pioglitazone treatment protects against another form of vascular wall disease, arteriosclerosis. In a rat model of elastocalcinotic arteriosclerosis (hypervitaminosis D and nicotine, VDN), we evaluated whether pioglitazone attenuated arteriosclerosis and its consequences, aortic wall rigidity, increased aortic pulse pressure and left ventricular hypertrophy. In VDN rats, medial calcification was associated with monocyte/macrophage infiltration and induction of TNF-alpha and IL-1B. Pioglitazone decreased TNF-alpha and IL-1B mRNA expression, blunted aortic wall calcification and prevented fragmentation of elastic fibers. Pioglitazone reduced aortic wall stiffness, aortic pulse pressure and left ventricular hypertrophy. Our results may be clinically relevant in elderly patients suffering from aortic wall stiffening and isolated systolic hypertension.

The present article analyses the intimate relationship between diabetes mellitus and congestive heart failure. This relationship is indeed "bidirectional". On the one hand, it is well known that diabetes mellitus, especially type 2 diabetes, predisposes to congestive heart failure due to intricated mechanisms. In most cases, there is a combination of various well-known risk factors, such as obesity, arterial hypertension and coronary heart disease, with a specific diabetic cardiomyopathy, whose pathophysiology is complex. On the other hand, several studies showed that congestive heart failure increases the risk of new type 2 diabetes, probably due to decreased muscular perfusion and excessive neurohumoral response. Remarkably, such a risk could be reduced by a drug capable of inhibiting the renin-angiotensin system, as previously reported in patients with arterial hypertension. The recent launch and the increasing use of thiazolidinediones (glitazones) raise the interest for congestive heart failure in diabetic patients. Indeed, because of their positive effect on insulin resistance and various pleiotropic effects, glitazones may exert some cardiovascular protection; however, both rosiglitazone and pioglitazone are associated with fluid retention, which could reveal or aggravate episodes of congestive heart failure.

Diabetic nephropathy is the leading cause of chronic renal failure (CRF) in Europe. About fifty percent of diabetic subjects develop microalbuminuria, which progresses towards established diabetic nephropathy in one third of patients. The treatment of type 2 diabetes in a patient with CRF is a challenge for the general practitioner, because of the accumulation of drugs and/or specific metabolites. Sulfonylureas are associated with an increased risk of hypoglycaemia. Biguanides may exceptionally cause life-threatening lactic acidosis. Glitazones have an interesting profile since they decrease microalbuminuria and blood pressure. However, their safety is not well defined in the context of CRF In the case of severe CRF, only insulin and repaglinide can be recommended.

The Avandia, tolérance à grande échelle (Avantage) study was an observational study conducted in a large cohort of type 2 diabetic patients (T2D) followed for 12 months. Its aim was to assess in real clinical practice conditions, the tolerability of rosiglitazone, an oral antidiabetic agent of the new thiazolidinedione ("glitazone") class, available in France since May 2002. Study was carried out from December 2002 to January 2005. To be included, T2D seen during the inclusion period should start the rosiglitazone treatment (within eight days prior to 15 days after) in agreement with therapeutic indications and drug datasheet information in force at that time. Patient characteristics, clinical and biological data and adverse events (AE) during the 12-month follow-up were recorded. Among the 3845 T2D enrolled from January to November 2003, 3580 constituted the analyzed population (at least one documented rosiglitazone intake). At inclusion, mean age (+/-S.D.) was 62+/-11 years, 52% were male, mean BMI was 29.9+/-5.3kg/m2 and mean HbA1c was 8.5+/-1.4%. Ongoing antidiabetic treatments were mainly a monotherapy (46% of patients, metformin or a sulfonylurea) or a bitherapy (in 47%). Main reasons to prescribe rosiglitazone were insufficient control of diabetes (91% of patients), associated or not with a poor tolerance to the ongoing oral antidiabetic treatment at inclusion (in 29%) and/or with a contraindication to metformin (in 4%). Two thousand four hundred and twenty-four patients (71%) completed the 12-month follow-up. Along the study, 514 T2D (14%) experienced at least one AE, judged related to the treatment in the physician's opinion for 377 patients (11%). Two hundred and fifteen patients dropped out from the study due to AE. AE notified in more than 1% of patients were: weight gain (n=100 patients; 3% of the cohort), nausea (n=57; 2%), edema (n=55; 2%) and anemia (n=40; 1%). A seriousness criteria was reported for 105 patients (3% of the cohort), including 18 (1%) heart failure. Mean HbA1c level decreased from 8.5+/-1.4% at inclusion to 7.8+/-1.6% at study end. Mean value of the main lipid parameters remained stable. Mean systolic blood pressure (BP) decreased from 137+/-13 to 135+/-12mmHg and diastolic BP from 79+/-8 to 78+/-8mmHg. Mean weight was 82+/-15kg at inclusion and 83+/-17kg at study end (NS), mean waist circumference was not significantly modified. In conclusion, the observational Avantage study, conducted in a large cohort of type 2 diabetic patients treated with rosiglitazone in clinical practice conditions and followed-up for 12 months, confirmed the results of controlled double blind clincal studies, with a clinical and biological tolerability in accordance with the known AE profile and a beneficial effect on metabolic control and arterial blood pressure.

The recent analysis of the French MONICA registries report a reduction in the incidence of fatal MI related to improvement of care whereas the overall incidence of coronary events remain stable, suggesting the need for a better primary prevention. The extensive review of the death certificates and the analysis of the death classification from the same registries indicate an under estimation of MI-related death in the national death registry. It is also confirmed that instead of 50%, approximately 80% of coronary death are explained by the four major risk factors including smoking, hypercholesterolemia, hypertension and diabetes. The international REACH registry has enrolled more than 67 000 individuals including patients with symptomatic atherothrombotic disease and patients with multiple risk factors. The analysis of baseline characteristics and of the one year FU shows a high residual risk and a lack of efficacy of secondary prevention. The existence of a symptomatic disease and the number of symptomatic localization of atherothrombosis are critical factors to predict recurrence of major vascular events Secondary analysis of the INTERHEART study provide the essence of what should any physician know about the relationship between coronary heart disease and smoking, either active or passive. Prevention with respect to this risk factor remains very insufficient. Varenicline, a new nicotinic receptor partial agonist, should help patients involved in smoking cessation program. The established detrimental effects of perioperative smoking represent a unique opportunity to promote smoking cessation in individuals scheduled for surgery. The major cardiovascular impact of second hand smoking has been recently demonstrated by the short-term effects of banning smoking in public places on the incidence of acute coronary events. The SPARCL study has demonstrated the benefit of high dose of atorvastatine to prevent recurrent acute ischemic cerebrovascular event in patients with a prior history of stroke or TIA. In the open ASTEROID study, high doses of rosuvastatine confirm the possibility of reducing the volume of coronary atheroma analyzed by IVUS. The expected benefit of glitazones to reduce the incidence of death, MI and stroke in diabetes patients with a prior history of vascular event has been confirmed in the PROactive study. Pioglitazone provided a clear reduction of recurrent vascular events in diabetes patient with a prior MI at a cost of a significant increase of the risk of heart failure. In the DREAM study, neither ramipril nor rosiglitazone have reduced the incidence of cardiovascular events significantly. The moderate benefit of the fenofibrate to prevent cardiovascular events in the FIELD study, which was carried out in diabetics mostly in primary prevention, needs to be considered after adjustment on statin use in a higher proportion of patients of the placebo group. Postprandial hyperglycaemia, analyzed by the peak of glycaemia after a load in glucose, has been confirmed as a more powerful independent predictive factor of the risk of cardiovascular event than fasting glycaemia. The systematic screening postprandial hyperglycaemia represents an interesting strategy for primary prevention which warrants further investigation. If obesity is a risk factor whose impact on morbi-mortality is well established, a French study shows that body mass index has an unfavourable influence on the cognitive functions in middle-aged men and women.

This article summarizes an important study published in 2006 in the field of the prevention of diabetes mellitus. It is the DREAM study which evaluate the therapeutic effects of rosiglitazone and ramipril versus placebo in the prevention of type 2 diabetes in high risk patients: glucose intolerance or impaired fasting glucose. In this clinical study, more than 5000 patients were followed during 3 years. The risk of diabetes was reduced with rosiglitazone of 62% (NNT 9). In the field of negative effects the risk of cardiac insufficiency was multiplied by 7 (NNH 250) but stayed a rare event (to 0,5% of the treated subjects). The ramipril had no preventive effect for the prevention of type 2 diabetes but induced a higher frequency of return towards the normoglycaemia. This treatment can be recommended for these high risk subjects.

ADOPT ("A Diabetes Outcome Progression Trial") is a double-blind, controlled clinical trial that aims at assessing the efficacy of rosiglitazone, as compared to metformin or glibenclamide, in maintaining long-term glycaemic control in patients with recently diagnosed type 2 diabetes. It randomized 4,360 patients who were followed for a median of 4.0 years. The cumulative incidence of monotherapy failure (defined as a confirmed level of fasting plasma glucose level of more than 180 mg/dl) averaged at 5 years 15% with rosiglitazone, 21% with metformin, and 34% with glibenclamide. This represents a risk reduction for rosiglitazone of 32% as compared to metformin and 63% as compared to glibenclamide (P0.001 for both comparisons). Rosiglitazone was associated with more weight gain and edema, metformin with a higher incidence of gastrointestinal events and glibenclamide with a higher risk of hypoglycaemia (P0.001). In conclusion, ADOPT showed better glycaemic durability with rosiglitazone monotherapy, compared to metformin or glibenclamide. The potential risks and benefits, the profile of adverse events, and the costs of the three drugs should all be considered to help inform the choice of pharmacotherapy for patients with type 2 diabetes.

DREAM ("Diabetes Reduction Assessment with ramipril and rosiglitazone Medication") is a double-blind randomised placebo-controlled clinical trial with a 2-by-2 factorial design aiming to study the effects of an ACE inhibitor (ramipril 15 mg/day) and/or a thiazolidinedione (rosiglitazone 8 mg/day) on the development of diabetes or death (primary outcome) and on the regression to normoglycaemia (secondary outcome) in 5269 adults aged 30 years or more with impaired fasting glucose and/or impaired glucose tolerance, and no previous cardiovascular disease. There was no statistical evidence of an interaction between the ramipril and the rosiglitazone arms. After a mean follow up of 3 years, the use of ramipril does not significantly reduce the incidence of diabetes or death but does significantly increase regression to normoglycaemia. In contrast, the treatment with rosiglitazone reduces by almost 60% the incidence of type 2 diabetes and increases the likelihood (+70%) of regression to normoglycaemia. Whether it is a true prevention effect or simply a treatment effect remains to be determined when participants will be retested after a washout period. Cardiovascular event rates were rather low and much the same in all treatment groups, except a higher rate of heart failure in the rosiglitazone group. These results suggest that the routine inhibition of the renin-angiotensin system for the express purpose of preventing diabetes is not indicated in individuals not at high risk for cardiovascular disease and appear to confirm the promises of the glitazone use in the very early stage of the natural history of type 2 diabetes.

PPARgamma has been recently described as being a gene of susceptibility for Intestinal Bowel Diseases (IBD) as NOD2/CARD15 gene. IBD are pathologies due to an abnormal immune response, in genetically predisposed patients, to the bacteria of the intestinal flora. PPARgamma, known for its significant role in adipogenesis, is strongly expressed by the epithelial cells of the colon mucosa. PPARgamma is implicated in the regulation of inflammation. Indeed, agonists of this nuclear receptor decrease strongly the intensity of inflammation during experimental colitis induced by chemical agents. A deficit of PPARgamma in patients with ulcerative colitis has been highlighted, that could in part explain the acute inflammation. In addition, bacteria, including those of the commensal flora, are able to regulate PPARgamma. Toll Like Receptor-4 (TLR-4), responsible for the recognition of bacterial motif as lipopolysaccharide (LPS), is implicated in PPARgamma regulation and its anti-inflammatory properties. All these arguments make of PPARgamma a very interesting therapeutic target for the treatment of IBD.

Drug treatment of 2 diabetes is intended to normalize glycosylated hemoglobin levels (HbA(1c)6.5%) and thereby prevent the development of micro- and macrovascular complications. Oral antidiabetic agents target the metabolic abnormalities that cause diabetes. The two principal families of oral antidiabetic agents - insulin sensitizers and insulin secretagogues - can be taken together. Thiazolidinediones or glitazones (insulin sensitizers) improve peripheral tissue sensitivity to insulin. Metformin (an insulin sensitizer) reduces hepatic glucose production. Sulfonylureas and meglitinides (insulin secretagogues) stimulate insulin secretion and can cause hypoglycemia. GLP-1 (Glucagon-Like Peptide-1) analogs and DPP-IV (dipeptidyl-peptidase-IV) inhibitors are new drug classes currently under development.

The 5' AMP-activated protein kinase (AMPK) is a sensor of cellular energy homeostasis well conserved in all eukaryotic cells. AMPK is activated by rising AMP and falling ATP, either by inhibiting ATP production or by accelerating ATP consumption, by a complex mechanism that results in an ultrasensitive response. AMPK is a heterotrimeric enzyme complex consisting of a catalytic subunit alpha and two regulatory subunits beta and gamma. AMP activates the system by binding to the gamma subunit that triggers phosphorylation of the catalytic alpha subunit by the upstream kinases LKB1 and CaMKKbeta. Once activated, it switches on catabolic pathways (such as fatty acid oxidation and glycolysis) and switches off ATP-consuming pathways (such as lipogenesis) both by short-term effect on phosphorylation of regulatory proteins and by long-term effect on gene expression. Dominant mutations in the regulatory gamma subunit isoforms cause hypertrophy of cardiac and skeletal muscle providing a link in human diseases caused by defects in energy metabolism. As well as acting at the level of the individual cell, the system also regulates food intake and energy expenditure at the whole body level, in particular by mediating the effects of adipokines such as leptin and adiponectin. Moreover, the AMPK system is one of the probable target for the anti-diabetic drug metformin and rosiglitazone. The relationship between AMPK activation and beneficial metabolic effects provides the rationale for the development of new therapeutic strategies. Thus, pharmacological AMPK activation may, through signaling, metabolic and gene expression effects, reduce the risk of Type 2 diabetes, metabolic syndrome and cardiac diseases.

This year, two prospective randomized studies aimed at the reduction of composite cardiovascular endpoints in type 2 diabetic patients. The PROactive study estimated the impact of pioglitazone in the secondary prevention. The significant reduction of the primary composite endpoint was not obtained: reduction of the relative risk (RR) of 10 % (p= 0.095). However, the secondary composite endpoint was significantly reduced RR 16 % (p = 0.027). The FIELD study also had the same objectives. The primary composite endpoint was not significantly reduced in spite of a RR of 11% while the reduction of RR was significant for the secondary composite endpoint (p = 0.035). These studies reveal the difficulties and the complexity of the secondary prevention of atherosclerosis for patients already treated with effective molecules.

PROactive is a prospective, randomised controlled trial in 5238 patients with type 2 diabetes who had evidence of macrovascular disease. Patients were assigned to oral pioglitazone titrated from 15 mg to 45 mg or matching placebo, to be taken in addition to their glucose-lowering drugs and other medications. After a mean follow up of 34.5 months, pioglitazone reduced the composite of all-cause mortality, non-fatal myocardial infarction, and stroke (intention to treat analysis: hazard ratio = 0.84; 95% CI: 0.72-0.98; p = 0.027). Various favourable metabolic effects could contribute to this cardiovascular protection, i.e. an absolute 0.5 % reduction in HbA1c, a 9% increase in HDL cholesterol, a 13% decline of triglycerides, and a 3 mm Hg reduction in systolic blood pressure in the pioglitazone group compared to placebo. The requirement of insulin was reduced by almost 50% in the pioglitazone group as compared to the placebo group. The incidence of cases of oedema and congestive heart failure was higher in the pioglitazone group. In conclusion, in patients with type 2 diabetes who are at high cardiovascular risk, pioglitazone improves cardiovascular outcome, and reduces the need to add insulin to glucose-lowering regimens compared to placebo.

Type 2 diabetes has a complex pathophysiology, combining a defect of insulin secretion by the pancreas, an increased glucose production by the liver and a reduced insulin-mediated glucose uptake by the skeletal muscle. Each of these abnormalities can be partially reversed by a specific drug, an agent promoting insulin secretion (sulphonylurea or glinide), metformin and a thiazolidinedione (glitazone), respectively. Therefore, a triple oral therapy, targeting simultaneously the three main metabolic abnormalities of type 2 diabetes, deserves special attention. Recent clinical trials have shown both the efficacy and safety of this triple oral therapy. However, its precise place remains to be better specified in the overall management of type 2 diabetes.

Insulin resistance has a genetic background and its phenotypic expression is triggered by fat diet, lack of physical activity and obesity. It provokes a stress on B cells, tends to increase blood glucose levels, is intimately associated with the metabolic syndrome and represents a major cardiovascular risk factor. Insulin resistance may be favourably influenced by simple life-style changes. If necessary, drugs may be prescribed, such as metformin, the first choice antidiabetic oral agent in overweight individuals, or thiazolidinediones (glitazones), new insulin sensitizers with promising effects. New molecules are currently developed, especially PPAR alpha/gamma or pan-agonists. Targeting insulin resistance has several objectives: reducing hyperglycaemia in type 2 diabetic patients, protecting B cells in order to prevent type 2 diabetes in at risk individuals and limiting the progressive metabolic deterioration in diabetic patients, finally, and perhaps most importantly, ameliorating the global cardiovascular prognosis.

Type 2 diabetes is a complex disease combining several disturbances in various organs, especially a defect of insulin secretion by the pancreas, an increased production of glucose by the liver and a reduced insulin-mediated glucose uptake by the skeletal muscle. Each of these abnormalities can be, at least partially, reversed by a specific pharmacological approach, an agent promoting insulin secretion (sulphonylurea, glinide), metformin and a thiazolidinedione (glitazone), respectively. A triple oral therapy with "sulphonylurea (glinide)--metformin--glitazone", targeting simultaneously the three main metabolic abnormalities of type 2 diabetes, deserves special attention. Promising results have been observed in recent clinical trials as far as blood glucose control and some other cardiovascular risk factors are concerned. The precise place of such oral triple therapy remains to be specified, at a late stage to delay the shift to insulin or earlier in the natural history of the disease, to avoid the decline of the number and/or function of beta cells and the resulting metabolic deterioration.