Immunolocalization of neuropeptide Y in human pancreatic endocrine tumors.

Neuropeptide Y (NPY) is a 36 amino acid peptide known to inhibit glucose-stimulated insulin secretion. NPY has recently been shown to be synthetized within rat islets of Langerhans and to be secreted in a differentiated rat insulin-secreting cell line, and as to this date the localization of NPY in human endocrine pancreas has not been reported. As NPY shares high amino acid sequence homology with peptide YY (PYY) and pancreatic polypeptide (PP), the polyclonal antibodies raised against these peptides often cross-react with each other. To demonstrate the presence of NPY in the human endocrine pancreas, we used a highly specific monoclonal antibody raised against NPY and another against its C-flanking peptide (CPON). We studied three cases of hyperplasia of Langerhans islets and 11 cases of endocrine tumors of the pancreas. NPY and CPON were detected in all three cases of hyperplasia. For the 11 pancreatic tumors, five and nine of the tumors were positive for the antibodies NPY and CPON, respectively. The two negative tumors for CPON immunoreactivity were differentiated insulinomas, which showed no evidence of other hormonal secretion. In normal Langerhans islet, NPY and CPON immunoreactivities were colocalized in glucagon-producing cells (alpha-cells) and in a few insulin-secreting cell (beta-cells).(ABSTRACT TRUNCATED AT 250 WORDS)

Syndrome métabolique, une maladie mitochondriale? [Metabolic syndrome, a mitochondrial disease?]

Le syndrome métabolique (SM) associe dyslipidémie, hypertension, intolérance au glucose, état pro-inflammatoire/prothrombotique et surpoids, dont nous vous présentons une hypothèse physiopathologique émergente. Des recherches récentes ont montré que des dysfonctions mitochondriales induisent l'accumulation intracellulaire d'acylCoA et de diacylglycérol, inactivant la signalisation de l'insuline par un effet direct sur les transporteurs du glucose insulino-dépendants. Un défaut de la phosphorylation oxydative conduirait à l'insulino-résistance. Des atteintes de la fonction mitochondriale sont présentes dans le muscle, le foie, le pancréas et les vaisseaux sanguins et contribuent aux manifestations cliniques. Ces observations des atteintes mitochondriales nous montrent un lien entre la clinique et la physiopathologie du SM. The metabolic syndrome is a cluster of metabolic risk factors including: atherogenic dyslipidemia, elevated blood pressure, high plasma glucose and a prothrombotic and proinflammatory state, frequently associated to overweight. Impaired cell metabolism has been suggested as a relevant pathophysiological process. Indeed, the accumulation of intracellular fatty acylCoA and diacylglycerol, which then activate critical signal transduction pathways that ultimatly lead to suppression of insulin signalisation. Therefore a defect in mitochondrial function may be responsible for insulin resistance. Moreover, mitochondrial dysfunction has been found to take place in organs such as skeletal muscle, liver, pancreas and smoth vascular cells suggesting that mitochondrial defect could play a critical role in the occurence of cardiovascular diseases.

Reduced atrial emptying after orthotopic heart transplantation masquerading as restrictive transmitral Doppler flow pattern?

BACKGROUND: An elevated early (E) to late (A) diastolic filling velocities ratio, typically seen in advanced diastolic dysfunction, has also been observed after cardioversion of atrial fibrillation as a consequence of the depressed left atrial (LA) contractility. We hypothesized that the impaired LA contractile function demonstrated after orthotopic cardiac transplantation (OCT) could also lead to this "pseudorestrictive" pattern. METHOD: E/A ratio related to the tissue Doppler early mitral annular velocity (Ea) as preload-independent index of LV relaxation was evaluated in all consecutive OCT patients between 2005 and 2007. RESULTS: The study population comprised 48 patients 97 ± 77 months after OCT. Thirty-two patients (67%) had an E/A ratio > 2. LV systolic function and myocardial relaxation assessed by the Ea velocity were similar compared to patients with normal ratio (61 ± 6% vs. 60 ± 12%, P = 0.854 and 15 ± 4 cm/s vs. 14 ± 3 cm/s, r = 0.15, P = 0.323, respectively). On the other hand, the proportion of the recipient and donor LA cuffs as estimated by the recipient/global LA area ratio and the LA emptying fraction significantly correlated with the E/A ratio (r = 0.40, P = 0.005 and r =-0.33, P = 0.022, respectively). CONCLUSION: Our study shows that there is a high prevalence of elevated E/A ratio after standard OCT which seems mainly related to reduced LA contractility. Recognition of this "pseudorestrictive" pattern may avoid misdiagnosis of diastolic dysfunction.

Neural regulation of pancreatic islet cell mass and function.

Intracellular glucose signalling pathways control the secretion of glucagon and insulin by pancreatic islet α- and β-cells, respectively. However, glucose also indirectly controls the secretion of these hormones through regulation of the autonomic nervous system that richly innervates this endocrine organ. Both parasympathetic and sympathetic nervous systems also impact endocrine pancreas postnatal development and plasticity in adult animals. Defects in these autonomic regulations impair β-cell mass expansion during the weaning period and β-cell mass adaptation in adult life. Both branches of the autonomic nervous system also regulate glucagon secretion. In type 2 diabetes, impaired glucose-dependent autonomic activity causes the loss of cephalic and first phases of insulin secretion, and impaired suppression of glucagon secretion in the postabsorptive phase; in diabetic patients treated with insulin, it causes a progressive failure of hypoglycaemia to trigger the secretion of glucagon and other counterregulatory hormones. Therefore, identification of the glucose-sensing cells that control the autonomic innervation of the endocrine pancreatic and insulin and glucagon secretion is an important goal of research. This is required for a better understanding of the physiological control of glucose homeostasis and its deregulation in diabetes. This review will discuss recent advances in this field of investigation.

Off-pump transapical mitral valve-in-ring implantation.

OBJECTIVES: The study aimed to evaluate the feasibility of off-pump transapical mitral valve-in-ring implantation and to test the performance of a custom-made self-expandable stent valve, in comparison with the standard SAPIEN valve. METHODS: Acute experiments were performed in five pigs. Animals (mean weight 58.4 ± 7.3 kg) underwent mitral valve annuloplasties under cardiopulmonary bypass using 26-mm rings (SJM?). Then, a 30-mm custom-made self-expandable stent valve or a 23-mm balloon-expandable transcatheter heart valve (Edwards SAPIEN XT?) was deployed within the annuloplasty rings through a transatrial access and under direct vision. Subsequently, the stent valves were inserted transapically under fluoroscopic guidance and off pump. RESULTS: The procedural success of transatrial and transapical mitral valve-in-ring procedures was 100% (10 of 10). Mean transatrial and transapical procedure time was 2.0 ± 1.1 and 22.0 ± 5.7 min, respectively. Haemodynamic status during transapical implantation remained stable, and differences in data collected before and after the stent-valve deployment were not statistically significant. Mean mitral annulus diameter and mean mitral orifice area in the group of self-expandable stent valves were 2.60 ± 0.02 cm and 4.16 ± 0.48 cm(2), respectively, whereas in the SAPIEN group they were 1.95 ± 0.18 cm and 2.26 ± 0.20 cm(2), respectively. Trace or mild regurgitation was detected only in the self-expandable stent-valve group. Mean gradients were 4.1 ± 4.5 mmHg across the self-expandable stent valves and 1.0 ± 0 mmHg across the SAPIEN valves. Postmortem examination confirmed adequate positioning of the self-expandable valves and the SAPIEN valves within the annuloplasty ring. CONCLUSIONS: Off-pump transapical mitral valve-in-ring implantation is safe and feasible. Transapical access may represent the ideal option for valve-in-ring procedures in cases of recurrent mitral regurgitation after mitral valve repair, in high-risk patients. Owing to the supra-annular profile of the valve components, our custom-made nitinol stent valve provides nearer to normal functional area than the SAPIEN valve.

Effects of age, birth cohort and period of death on Swiss cancer mortality, 1951-1984.

Swiss death certification data over the period 1951-1984 for total cancer mortality and 30 major cancer sites in the population aged 25 to 74 years were analysed using a log-linear Poisson model with arbitrary constraints on the parameters to isolate the effects of birth cohort, calendar period of death and age. The overall pattern of total cancer mortality in males was stable for period values and showed some moderate decreases in cohort values restricted to the generations born after 1930. Cancer mortality trends were more favourable in females, with steady, though moderate, declines in both cohort and period values. According to the estimates from the model, the worst affected generation for male lung cancer was that born around 1910, and a flattening of trends or some moderate decline was observed for more recent cohorts, although this decline was considerably more limited than in other European countries. There were decreases in cohort and period values for stomach, intestine and oesophageal cancer in both sexes and (cervix) uteri in females. Increases were observed in both cohort and period trends for pancreas and liver in males and for several other neoplasms, including prostate, brain, leukaemias and lymphomas, restricted, however, for the latter sites, to the earlier cohorts and hence partly attributable to improved diagnosis and certification in the elderly. Although age values for lung cancer in females were around 10-times lower than in males, upward trends in female lung cancer cohort values were observed in subsequent cohorts and for period values from the late 1960's onwards. Therefore, future trends in female lung cancer mortality should continue to be monitored. The application of these age/period/cohort models thus provides a summary guide for the reading and interpretation of cancer mortality trends, although it cannot replace careful inspection of single age-specific rates.

Alzheimer disease: curly fibers and tangles in organs other than brain.

The filamentous brain lesions that define Alzheimer disease (AD) consist of senile plaques and neurofibrillary tangles. Undulated pathological filaments--curly fibers or neuropil threads--also occur in the neuropil. Beta-amyloid precursor proteins are synthesized by many cells outside the central nervous system and recently, deposition of beta-amyloid-protein was reported to occur in non-neuronal tissues. In addition, increasing data claim the importance of chronic inflammation in the pathogenesis of AD. These observations suggest that AD may be a widespread systemic disorder. Here we report that pathological argyrophilic filaments with histochemical properties of amyloid showing striking morphological similarity to curly fibers and/or tangles accumulate not only in ependymal layer and in epithelial cells of choroid plexus, but also in several other organs (e.g. liver, pancreas, ovary, testis, thyroid) in AD. The ependyma, choroid plexus, and various organs of 39 autopsy cases were analyzed. In search of curly fiber and tangle-like changes in organs other than brain, 395 blocks from 21 different tissues of 24 AD cases, 5 cases with discrete or moderate AD-type changes, and 10 control cases were investigated. We found in non-neuronal cells "curly fibers" or "tangles" immunoreactive with antibodies to P component, Tau-protein, ubiquitin, fibronectin, and Apolipoprotein-E, but lacking immunoreactivity with antibodies to neurofilament proteins. Ultrastructurally they consist of densely packed straight and paired helical filaments and closely resemble neurofibrillary tangles and neuropil threads. These observations indicate that the formation of "curly fibers" and "tangles" is not unique to the central nervous system. The results suggest that AD might be a systemic disorder or that similar fibrillary changes to tangles and curly fibers may also be associated with other amyloidosis than beta-amyloidosis. Further investigations are necessary to understand the pathogenetic interest of these fibrillary changes outside the CNS.

Localized interstitial granuloma annulare induced by subcutaneous injections for desensitization.

We describe a patient with interstitial granuloma annulare associated with subcutaneous injection therapy (SIT) for desensitization to a type I allergy. Asymptomatic, erythematous, violaceous annular patches were located at the injection sites on both her arms. Medical history revealed perennial rhinoconjonctivitis treated with SIT (Phostal Stallergen® cat 100% and D. pteronyssinus/D.farinae 50%:50%).

The role of microRNAs in the development of type 2 diabets

Pancreatic ß cells are highly specialized endocrine cells located within the islets of Langerhans in the pancreas. Their main role is to produce and secrete insulin, the hormone essential for the regulation of glucose homeostasis and body's metabolism. Diabetes mellitus develops when the amount of insulin released by ß cells is not sufficient to cover the metabolic demand. In type 1 diabetes (5-10% of diagnoses) insulin deficiency is caused by the autoimmune destruction of pancreatic ß cells. Type 2 diabetes (90% of diagnoses) results from a genetic predisposition and from the presence of adverse environmental conditions. The combination of these factors reduces insulin sensitivity of peripheral target tissues, causes impairment in ß-cell function and can lead to partial loss of ß cells. The development of novel therapeutic strategies for the treatment of diabetes necessitates the comprehension of the cellular processes involved in dysfunction and loss of ß cells. My thesis was focused on the involvement in the physiopathological processes leading to the development of diabetes of a class of small regulatory RNA molecules, called microRNAs (miRNAs) that post- transcriptionally regulate gene expression. Global miRNA profiling in pancreatic islets of two animal models of diabetes, the db/db mice and mice that were fed a high fat diet (HFD), characterized by obesity and insulin resistance, led us to identify two groups of miRNAs displaying expression changes under pre-diabetic and diabetic conditions. Among the miRNAs already upregulated in pre-diabetic db/db mice and HFD mice, miR- 132 was found to have beneficial effects on pancreatic ß cell function and survival. Indeed, mimicking the upregulation of miR-132 in primary pancreatic islet cells and ß-cell lines improved glucose- induced insulin secretion and favored survival of the cells upon exposure to pro-apoptotic stimuli such as palmitate and cytokines. MiR-132 was found to exert its action by enhancing the expression of MafA, a transcription factor essential for ß-cell function, survival and identity. On the other hand, up-regulation of miR-199a-5p and miR-199a-3p was detectable only in the islets of diabetic db/db mice and resulted in impaired insulin secretion and sensitization of the cells to apoptosis. MiR-199a- 5p was found to decrease insulin secretion by inducing the expression of granuphilin, a potent inhibitor of ß cell exocytosis. In contrast, miR-199a-3p was demonstrated to directly target and reduce the expression of two key ß-cell genes, mTOR and cMET, resulting in impaired ß-cell adaptation to metabolic demands and loss by apoptosis. Our findings suggest that miRNAs are important players in the onset of type 2 diabetes. MiRNA expression is adjusted in pancreatic ß cells exposed to a diabetogenic environment. These changes initially concern miRNAs responsible for adaptive processes aimed at compensating the onset of insulin resistance, but later such changes can be overlapped by modifications in the level of several additional miRNAs that favor ß-cell failure and the onset of type 2 diabetes.

Diffuse nesidioblastosis with hypoglycemia mimicking an insulinoma: a case report.

INTRODUCTION: We describe a case of diffuse nesidioblastosis in an adult patient who presented with exclusively fasting symptoms and a focal pancreatic 111In-pentetreotide uptake mimicking an insulinoma. CASE PRESENTATION: A 23-year-old Caucasian man had severe daily fasting hypoglycemia with glucose levels below 2mmol/L. Besides rare neuroglycopenic symptoms (confusion, sleepiness), he was largely asymptomatic. His investigations revealed low venous plasma glucose levels, high insulin and C-peptide levels and a 72-hour fast test that were all highly suggestive for an insulinoma. Abdominal computed tomography and magnetic resonance imaging did not reveal any lesions. The sole imagery that was compatible with an insulinoma was a 111In-somatostatin receptor scintigraphy that showed a faint but definite focal tracer between the head and the body of the pancreas. However, this lesion could not be confirmed by endoscopic ultrasonography of the pancreas. Following duodenopancreatectomy, the histological findings were consistent with diffuse nesidioblastosis. Postoperatively, the patient continued to present with fasting hypoglycemia and was successfully treated with diazoxide. CONCLUSION: In the absence of gastrointestinal surgery, nesidioblastosis is very rare in adults. In addition, nesidioblastosis is usually characterized by post-prandial hypoglycemia, whereas this patient presented with fasting hypoglycemia. This case also illustrates the risk for a false positive result of 111In-pentetreotide scintigraphy in the case of nesidioblastosis. Selective arterial calcium stimulation and venous sampling is the most reliable procedure for the positive diagnosis of insulinoma or nesidioblastosis and should be used to confirm any suspicion based on imaging modalities.

In rats, oral oleoyl-DHEA is rapidly hydrolysed and converted to DHEA-sulphate

Background: Dehydroepiandrosterone (DHEA) released by adrenal glands may be converted to androgens and estrogens mainly in the gonadal, adipose, mammary, hepatic and nervous tissue. DHEA is also a key neurosteroid and has antiglucocorticoid activity. DHEA has been used for the treatment of a number of diseases, including obesity; its pharmacological effects depend on large oral doses, which effect rapidly wanes in part because of its short half-life in plasma. Since steroid hormone esters circulate for longer periods, we have studied here whether the administration of DHEA oleoyl ester may extend its pharmacologic availability by keeping high circulating levels. Results: Tritium-labelled oleoyl-DHEA was given to Wistar male and female rats by gastric tube. The kinetics of appearance of the label in plasma was unrelated to sex; the pattern being largely coincident with the levels of DHEA-sulfate only in females, and after 2 h undistinguishable from the results obtained using labelled DHEA gavages; in the short term, practically no lipophilic DHEA label was found in plasma. After 24 h only a small fraction of the label remained in the rat organs, with a different sex-related distribution pattern coincident for oleoyl- and free- DHEA gavages. The rapid conversion of oleoyl-DHEA into circulating DHEA-sulfate was investigated using stomach, liver and intestine homogenates; which hydrolysed oleoyl-DHEA optimally near pH 8. Duodenum and ileum contained the highest esterase activities. Pure hog pancreas cholesterol-esterase broke down oleoyl-DHEA at rates similar to those of oleoyl-cholesterol. The intestinal and liver esterases were differently activated by taurocholate and showed different pH-activity patterns than cholesterol esterase, suggesting that oleoyl-DHEA can be hydrolysed by a number of esterases in the lumen (e.g. cholesterol-esterase), in the intestinal wall and the liver. Conclusion: The esterase activities found may condition the pharmacological availability (and depot effect) of orally administered steroid hormone fatty acid esters such as oleoyl-DHEA. The oral administration of oleoyl-DHEA in order to extend DHEA plasma availability has not been proved effective, since the ester is rapidly hydrolysed, probably in the intestine itself, and mainly converted to DHEA-sulfate at least in females.

Involvement of the RasGAP derived fragment N in the resistance of pancreatic beta cells towards apoptosis

RESUME DESTINE AUX NON SCIENTIFIQUESLe diabète est une maladie associée à un excès de glucose (sucre) dans le sang. Le taux de glucose sanguin augmente lorsque l'action d'une hormone, l'insuline, responsable du transport du glucose du sang vers les tissus de l'organisme diminue, ou lorsque les quantités d'insuline à disposition sont inadéquates.L'une des causes communes entre les deux grands types de diabète connus, le type 1 et le type 2, est la disparition des cellules beta du pancréas, spécialisées dans la sécrétion d'insuline, par mort cellulaire programmée aussi appelée apoptose. Alors que dans le diabète de type 1, la destruction des cellules beta est causée par notre propre système immunitaire, dans le diabète de type 2, la mort de ces cellules, est principalement causée par des concentrations élevées de graisses saturés ou de molécules impliquées dans l'inflammation que l'on rencontre en quantités augmentées chez les personnes obèses. Etant donné l'augmentation épidémique du nombre de personnes obèses de par le monde, on estime que le nombre de personnes diabétiques (dont une majorité sont des diabétiques de type 2), va passer de 171 million en l'an 2000, à 366 million en l'an 2030, expliquant la nécessité absolue de mettre au point de nouvelles stratégies thérapeutique pour combattre cette maladie.L'apoptose est un processus complexe dont la dérégulation induit de nombreuses affections allant du cancer jusqu'au diabète. L'activation de caspase 3, une protéine clé contrôlant la mort cellulaire, était connue pour systématiquement mener à la mort cellulaire programmée. Ces dernières années, notre laboratoire a décrit des mécanismes de survie qui sont activés par caspase 3 et qui expliquent sans doute pourquoi son activation ne mène pas systématiquement à la mort cellulaire. Lorsqu'elle est faiblement activée, caspase 3 clive une autre protéine appelée RasGAP en deux protéines plus courtes dont l'une, appelée le fragment Ν a la particularité de protéger les cellules contre l'apoptose.Durant ma thèse, j'ai été impliqué dans divers projets destinés à mieux comprendre comment le fragment Ν protégeait les cellules contre l'apoptose et à savoir s'il pouvait être utilisé comme outil thérapeutique dans les conditions de survenue d'un diabète expérimental. C'est dans ce but que nous avons créé une souris transgénique, appelée RIP-N, exprimant le fragment Ν spécifiquement dans les cellules beta. Comme attendu, les cellules beta de ces souris étaient plus résistantes à la mort induite par des composés connus pour induire le diabète, comme certaines molécules induisant l'inflammation ou les graisses saturées. Nous avons ensuite pu montrer que les souris RIP-N étaient plus résistantes à la survenue d'un diabète expérimental que ce soit par l'injection d'une drogue induisant l'apoptose des cellules beta, que ce soit dans un fond génétique caractérisé par une attaque spontanée des cellules beta par le système immunitaire ou dans le contexte d'un diabète de type 2 induit par l'obésité. Dans plusieurs des modèles animaux étudiés, nous avons pu montrer que le fragment Ν protégeait les cellules en activant une voie protectrice bien connue impliquant successivement les protéines Ras, PI3K et Akt ainsi qu'en bloquant la capacité d'Akt d'activer le facteur NFKB, connu pour être délétère pour la survie de la cellule beta. La capacité qu'a le fragment Ν d'activer Akt tout en prévenant l'activation de NFKB par Akt est par conséquent particulièrement intéressante dans l'intégration des signaux régulant la mort cellulaire dans le contexte de la survenue d'un diabète.La perspective d'utiliser le fragment Ν comme outil thérapeutique dépendra de notre capacité à activer les signaux protecteurs induits par le fragment Ν depuis l'extérieur de la cellule ou de dériver des peptides perméables aux cellules possédant les propriétés du fragment N.2 SUMMARYDiabetes mellitus is an illness associated with excess blood glucose. Blood glucose levels raise when the action of insulin decreases or when insulin is provided in inappropriate amounts. In type 1 diabetes (T1D) as well as in type 2 diabetes (T2D), the insulin secreting beta cells in the pancreas undergo controlled cell death also called apoptosis. Whereas in T1D, beta cells are killed by the immune system, in T2D, they are killed by several factors, among which are increased blood glucose levels, increased levels of harmful lipids or pro-inflammatory cytokines that are released by the dysfunctional fat tissue of obese people. Given the epidemic increase in the number of obese people throughout the world, the number of diabetic people (a majority of which are type 2 diabetes) is estimated to rise from 171 million affected people in the year 2000 to 366 million in 2030 explaining the absolute requirement for new therapies to fight the disease.Apoptosis is a very complex process whose deregulation leads to a wide range of diseases going from cancer to diabetes. Caspase 3 although known as a key molecule controlling apoptosis, has been shown to have various other functions. In the past few years, our laboratory has described a survival mechanism, that takes place at low caspase activity and that might explain how cells that activate their caspases for reasons other than apoptosis survive. In such conditions, caspase 3 cleaves another protein called RasGAP into two shorter proteins, one of which, called fragment N, protects cells from apoptosis.We decided to check whether fragment Ν could be used as a therapeutical tool in the context of diabetes inducing conditions. We thus derived a transgenic mouse line, called RIP-N, in which the expression of fragment Ν is restricted to beta cells. As expected, the beta cells of these mice were more resistant ex-vivo to cell death induced by diabetes inducing factors. We then showed that the RIP-N transgenic mice were resistant to streptozotocin induced diabetes, a mouse model mimicking type 1 diabetes, which correlated to fewer number of apoptotic beta cells in the pancreas of the transgenic mice compared to their controls. The RIP-N transgene also delayed overt diabetes development in the NOD background, a mouse model of autoimmune type 1 diabetes, and delayed the occurrence of obesity induced hyperglycemia in a mouse model of type 2-like diabetes. Interestingly, fragment Ν was mediating its protection by activating the protective Akt kinase, and by blocking the detrimental NFKB factor. Our future ability to activate the protective signals elicited by fragment Ν from the outside of cells or to derive cell permeable peptides bearing the protective properties of fragment Ν might condition our ability to use this protein as a therapeutic tool.3 RESUMELe diabète est une maladie associée à un excès de glucose plasmatique. La glycémie augmente lorsque l'action de l'insuline diminue ou lorsque les quantités d'insuline à disposition sont inadéquates. Dans le diabète de type 1 (D1) comme dans le diabète de type 2 (D2), les cellules beta du pancréas subissent la mort cellulaire programmée aussi appelée apoptose. Alors que dans le D1 les cellules beta sont tuées par le système immunitaire, dans le D2 elles sont tuées par divers facteurs parmi lesquels on trouve des concentrations élevées de glucose, d'acides gras saturés ou de cytokines pro-inflammatoires qui sont sécrétées en concentrations augmentées par le tissu adipeux dysfonctionnel des personnes obèses. Etant donné l'augmentation épidémique du nombre de personnes obèses de par le monde, on estime que le nombre de personnes diabétiques (dont une majorité sont des diabétiques de type 2), va passer de 171 million en l'an 2000, à 366 million en l'an 2030, justifiant la nécessité absolue de mettre au point de nouvelles stratégies thérapeutique pour combattre cette maladie.L'apoptose est un processus complexe dont la dérégulation induit de nombreuses affections allant du cancer jusqu'au diabète. Caspase 3, bien que connue comme étant une protéine clé contrôlant l'apoptose a bien d'autres fonctions démontrées. Ces dernières années, notre laboratoire a décrit un mécanisme de survie qui est activé lorsque caspase 3 est faiblement activée et qui explique probablement comment des cellules qui ont activé leurs caspases pour une autre raison que l'apoptose peuvent survivre. Dans ces conditions, caspase 3 clive une autre protéine appelée RasGAP en deux protéines plus courtes dont l'une, appelée le fragment Ν a la particularité de protéger les cellules contre l'apoptose.Nous avons donc décidé de vérifier si le fragment Ν pouvait être utilisé comme outil thérapeutique dans les conditions de survenue d'un diabète expérimental. Pour se faire, nous avons créé une souris transgénique, appelée RIP-N, exprimant le fragment Ν spécifiquement dans les cellules beta. Comme attendu, les cellules beta de ces souris étaient plus résistantes ex-vivo à la mort induite par des facteurs pro-diabétogènes. Nous avons ensuite pu montrer que les souris RIP-N étaient plus résistantes à la survenue d'un diabète induit par la streptozotocine, un drogue mimant la survenue d'un D1 et que ceci était corrélée à une diminution du nombre de cellules en apoptose dans le pancréas des souris transgéniques comparé à leurs contrôles. L'expression du transgène a aussi eu pour effet de retarder la survenue d'un diabète franc dans le fond génétique NOD, un modèle génétique de diabète de type 1 auto-immun, ainsi que de retarder la survenue d'une hyperglycémie dans un modèle murin de diabète de type 2 induit par l'obésité. Dans plusieurs des modèles animaux étudiés, nous avons pu montrer que le fragment Ν protégeait les cellules en activant la kinase protectrice Akt ainsi qu'en bloquant le facteur délétère NFKB. La perspective d'utiliser le fragment Ν comme outil thérapeutique dépendra de notre capacité à activer les signaux protecteurs induits par le fragment Ν depuis l'extérieur de la cellule ou de dériver des peptides perméables aux cellules possédant les propriétés du fragment

Infectious Disease Burden after Solid Organ Transplantation (SOT) in the Swiss Transplant Cohort Study (STCS).

Infectious diseases (ID) are a major cause of morbidity and mortality after SOT. Since May 2008, the STCS has registered 95% of all SOT recipients in Switzerland. The extensive data set includes pre- and post-transplant variables that are prospectively collected at transplantation, 6 months post-transplant, and yearly thereafter. All ID events are recorded using internationally validated defi nitions. We obtained data from 1101 patients (79 heart, 685 kidney, 29 kidney-pancreas, 212 liver, and 96 lung transplants). So far the median observation times were 0.8 (IQR 0.3-1.4; heart); 1.1 (0.6-1.8, kidney); 1.1 (0.6-1.9, kidney-pancreas); 1.0 (0.5-1.7, liver); and 0.9 years (0.5-1.5, lung). The highest rates of proven or probable ID events were seen in lung (76%), followed by liver (64%), heart (62%), kidney-pancreas (62%), kidney (58%). During the observation period, ID was the cause of death in 19 patients (1.7%). Rates of infections per person-years according to pathogen and type of transplantation are shown in Figure 1. The data indicate that virus infections are only second after bacteria whereas fungi occur at relatively low rates. This prospective and standardized long-term collection of all ID events will allow a comprehensive assessment of the burden of ID across all SOT types in Switzerland. Regular analysis will identify new trends, serve as a quality control and help design anti-infectious interventions aiming at increasing safety and improving overall transplantation outcome.

Expression of Chemokine Receptors in Uveal Melanoma

Purpose:Chemokine receptors are transmembrane G coupled proteins that might be involved in the directional metastatic migration of tumor cells to specific organs. CXCR4 and CCR7 have been implicated in the selective metastasis of cutaneous melanoma cells to lung and lymph node, respectively. CCR6 is expressed in metastases from colon, ovarian and thyroid carcinomas to the liver where its ligand, CCL20, is constitutively expressed. As uveal melanomas frequently metastasize to the liver, we hypothesized that specific chemokine receptors and their respective ligands might be involved in metastasis of uveal melanoma to the liver. Methods:Tissue microarrays were constructed using 100 non irradiated primary uveal melanomas and 84 liver metastases, as well as 12 non liver metastases, collected from the files of Jules Gonin Eye Hospital and Pathology Institute, University of Lausanne. Immunohistochemistry was performed using anti-human CXCR4, SDF1, CCR7, CCL21 and CCR6 antibodies. Results:CXCR4 expression was detected in 36% of primary uveal melanomas and in 63% of liver metastases but no expression was found in metastases to other organs, except for one pancreatic metastasis. SDF1 expression was detected in 3% of primary uveal melanomas and in 26% of liver metastases, as well as in pancreas, lymph node and breast metastases. CCR6 expression was observed in the majority of primary uveal melanomas and liver metastases (73 and 88%, respectively). In addition, CCR6 was also detected in 9 metastases to other organs (pancreas, thyroid, lymph node, skin and breast). CCR7 and CCL21 were neither detected in primary uveal melanoma, nor in the metastases. Conclusions:Chemokine receptors CCR6 and CXCR4 are expressed in a large number of primary uveal melanomas and in uveal melanoma metastases to the liver. CCR6 is also expressed in a small number of metastases to other organs. These findings form the basis for further studies on the potential involvement of CXCR4 and CCR6 in the selective metastasis of uveal melanoma to the liver.