Introdução: Modelos experimentais em suíno são essenciais para pesquisa e treinamento em transplante de fígado. No entanto, este animal apresenta instabilidade hemodinâmica grave durante a fase anepática, exigindo um curto período anepático (não apropriado para fins de treinamento) ou o uso de circulação extracorpórea (que está associado a significativas complicações intra-operatórias). Além disso, a maioria dos modelos em suíno é alogênico, o que não é nem eticamente nem economicamente adequado para treinamento cirúrgico. Objetivo: Desenvolver e testar um modelo de autotransplante hepático em suínos sem o uso de circulação extracorpórea. Métodos: Onze porcos da raça Sus domesticus foram submetidos a cirurgia simulada (SHAM; n = 3) ou autotransplante de fígado (grupo experimental (GE); n = 8) sem o uso de circulação extracorpórea. Após a realização de uma incisão em \"J\", o hilo hepático foi inteiramente dissecado abaixo do nível da artéria gastroduodenal e o fígado completamente mobilizado. A aorta supracelíaca foi então dissecada através do pilar esquerdo do diafragma. Nenhuma outra etapa foi realizada no grupo SHAM. No GE, a partir de então, procedeu-se o autotransplante ortotópico de fígado empregando-se a técnica convencional com duas anastomoses de veia cava, semelhante à técnica clássica utilizada na prática clínica. Durante a fase anepática, foi utilizando o clampeamento da aorta supracelíaca a fim de manter a estabilidade hemodinâmica e evitar o uso do by-pass. Os animais foram submetidos a eutanásia 1h após o término do procedimento cirúrgico. Parâmetros hemodinâmicos e exames laboratoriais foram sistematicamente coletados em 4 tempos distintos: basal, pré-reperfusão, 5min após reperfusão e ao término do experimento. Foi realizada a análise histopatológica do enxerto após a reperfusão. A análise estatística foi feita comparando amostras relacionadas, no GE, e duas amostras independentes, entre os grupos. Resultados: Empregando a técnica por nós padronizada, obteve-se 100% de sobrevida dos animais, todos estáveis hemodinamicamente. Os tempos médios de observação pós-reperfusão e anepático foram de 136±12,50min e 47,88±8,03min, respectivamente. Não houve diferença estatística na pressão arterial média (PAM) entre o início e término do experimento no GE, nem entre os grupos durante a fase anepática. Ao término do experimento, a PAM foi significantemente maior no grupo SHAM quando comparado ao GE. A análise comparativa dos exames laboratoriais entre os grupos demonstrou que o pH, o bicarbonato e o base excess foram significantemente inferiores no GE 5min após a reperfusão e ao término do experimento. O lactato mostrou-se ser significantemente inferior ao término do experimento no grupo SHAM. Conclusão: De acordo com os métodos utilizados no presente estudo, desenvolveu-se um modelo de autotransplante de fígado em suínos sem a utilização de mecanismo de circulação extracorpórea. Para tanto, utilizou-se o clampeamento da aorta supracelíaca durante o período anepático. O modelo proposto é factível por cirurgiões em treinamento e com baixa mortalidade / Background: Experimental swine models have been essential for liver transplantation research and training. However, it experiences severe hemodynamic instability during the anhepatic phase, requiring either a short anhepatic phase (not appropriate for training purposes) or an extracorporeal circulation (which is linked to significant intraoperative complications). Furthermore, most of swine models are allograft ones, which is neither ethically nor financially suitable for surgical training. Objective: To develop and test a liver autotransplantation model in pig without venovenous bypass. Methods: Eleven Sus domesticus pigs underwent either sham surgery (SHAM group; n=3) or liver autotransplantation without venovenous bypass (experimental group (GE); n=8) by resident or fellow from Digestive Organs Transplant Division. After performing a rightsided J-shaped incision, hepatic hilum was entirely dissected under the level of the gastroduodenal artery and liver completely mobilized. Supraceliac aorta was then dissected through the diaphragm\'s left crus. No further step was performed in SHAM group. In the GE, thereafter, a liver autotransplantation was performed applying conventional bicaval anastomosis technique, similar to the classic technique used in clinical setting. During anhepatic phase, supraceliac aorta cross-clamping maneuver was carried out to sustain hemodynamic stability and avoid venovenous bypass. Animals underwent euthanasia one hour after the end of surgical procedure. Hemodynamic variables and blood samples were systematically collected at 4 different times: baseline, pre-reperfusion, 5min after reperfusion and at the end of experiment. Histological analysis of the graft was performed after reperfusion. Statistical analysis was accomplished comparing related samples in the GE and two independent samples between groups. Results: Applying the technique standardized by us, 100% survival was accomplished, all the animals hemodynamically stable. The mean post-reperfusion observation and anhepatic phase times were 136 ± 12.50 min and 48.38 ± 7.80 min, respectively. There was no statistical difference in mean arterial pressure (MAP) between baseline and the end of the experiment time in the GE, nor between the groups during the anhepatic phase. At the end of the experiment, MAP was significantly higher in the SHAM group compared to the experiment group. Blood samples statistical analysis between groups showed that pH, bicarbonate and base excess were significantly lower at 5 min post-reperfusion time and at the end of the experiment in the GE. The lactate was shown to be significantly lower in the SHAM group at the end of the experiment. Conclusion: According to the methods applied in the present study, a model of liver autotransplantation in swine was developed without the use of an extracorporeal circulation mechanism. For this purpose, supraceliac aortic cross-clamping maneuver was carried out during the anhepatic phase. The advocated model is feasible for training purpose with low mortality

INTRODUÇÃO: A fistula esofagorrespiratória é complicação temida do câncer esofágico avançado. A paliação com prótese metálica autoexpansível é método amplamente empregado, porém com resultados conflitantes. OBJETIVO: Identificar fatores associados ao insucesso clínico do tratamento da fístula esofagorrespiratória maligna com prótese metálica autoexpansível. MÉTODOS: Estudo retrospectivo através da análise de banco de dados elaborado de forma prospectiva de pacientes submetidos ao tratamento da fístula esofagorrespiratória maligna com prótese metálica autoexpansível entre janeiro de 2009 e fevereiro de 2016 em hospital terciário dedicado ao tratamento do câncer. Foram coletados dados quanto à: características demográficas, nível de albumina sérica, capacidade funcional do paciente, doença pulmonar infecciosa em atividade no momento da passagem da prótese, tratamentos oncológicos prévios, momento do diagnóstico da fístula, tamanho e localização do trajeto fistuloso. RESULTADOS: Um total de 71 pacientes foram incluídos no estudo (55 homens, idade média de 59 anos). Insucesso clínico ocorreu em 44.3% dos pacientes. ECOG 3 ou 4, desenvolvimento da fístula durante o tratamento do câncer esofágico e diâmetro da fístula >= 1 cm foram fatores preditivos do insucesso clínico. ECOG 3 ou 4, doença pulmonar infecciosa em atividade no momento da passagem da prótese e tratamento oncológico prévio com radioterapia foram fatores preditivos de menor sobrevida. O grau de disfagia melhorou significativamente 15 dias após a passagem da prótese. A taxa total de eventos adversos foi de 30%. Migração da prótese e a oclusão da mesma por crescimento tumoral nas extremidades da prótese foram os eventos adversos mais comumente observados. CONCLUSÃO: A prótese metálica autoexpansível é um método terapêutico efetivo para o tratamento da fístula esofagorrespiratória maligna, no entanto, ECOG 3 ou 4, desenvolvimento da fístula durante o tratamento do câncer esofágico e diâmetro da fístula >= 1cm foram fatores preditivos do insucesso clínico após a passagem da prótese / INTRODUCTION: Malignant esophagorespiratory fistula is a serious and life-threatening complication of esophageal cancer. Self-expandable metal stents placement is a well accepted palliative treatment, however, with conflicting results. OBJECTIVE: To identify risk factors associated with clinical failure after self-expandable metal stents placement for the treatment of malignant esophagorespiratory fistula. METHODS: This was a retrospective analysis of a prospectively maintained database used at a tertiary cancer hospital, with patients treated with SEMS placement for MERF between January 2009 and February 2016. The following variables were collected: patient demographics, serum albumin level, Eastern Cooperative Oncology Group (ECOG) performance status, pulmonary infection, previous oncologic treatment, moment of diagnosis of the malignant esophagorespiratory fistula, size and classification of the fistulous tract. RESULTS: A total of 71 patients (55 males, mean age 59 years) were considered for the final analysis. Clinical failure occurred in 44.3% of the patients. ECOG 3 or 4, fistula development during esophageal cancer treatment and fistula diameter >= 1cm were factors associated with increased risk of clinical failure. ECOG 3 or 4, pulmonary infection at the time of SEMS placement and prior radiation therapy were predictive factors associated with lower overall survival. Dysphagia scores improved significantly 15 days after stent insertion. The overall stent-related adverse events rate was 30%. Stent migration and occlusion due to tumor overgrowth were the most commonly seen adverse events. CONCLUSION: SEMS placement is a reasonable treatment option for MERF, however, ECOG 3 or 4, fistula development during esophageal cancer treatment or large fistula diameter may be independent predictors of clinical failure after stenting

INTRODUÇÃO: Obesidade é, hoje, considerada uma pandemia, com cerca de 500 milhões de obesos no mundo, com cerca de 2,8 milhões de mortes por ano. A cirurgia de bypass gástrico é um importante tratamento para obesidade, porém, não é isenta de riscos. O dispositivo temporário de exclusão duodeno jejunal - DTED (EndoBarrier Gastrointestinal Liner® GIDynamics, Inc. Lexington, MA), apresenta-se como uma nova forma de tratamento endoscópico da obesidade. Apesar dos bons resultados, os mecanismos de ação do DTED ainda não foram estudados, podendo as alterações humorais e do esvaziamento gástrico promovidas, ser os principais responsáveis pelos resultados obtidos. OBJETIVO: Estudar as alterações promovidas pelo DTED no esvaziamento gástrico, e a relação destas alterações com os resultados clínicos de perda de peso e controle do diabetes tipo 2. MÉTODOS: Vinte e cinco obesos e com diabetes tipo 2, que fizeram uso do DTED por período mínimo de 16 semanas e máximo de 24 semanas, realizaram teste de esvaziamento gástrico cintilográfico, antes, durante a 16ª semana de uso e após 4 semanas de retirada do DTED. Foram obtidas medidas de peso e hemoglobina glicada. As médias e desvio-padrão de retenção gástricas foram obtidas e comparadas entre os três exames realizados, e, após, comparados entre os pacientes que obtiveram e os que não obtiveram melhora no parâmetro clínico selecionado (perda de peso maior que 10%, e hemoglobina glicada menor que 7%). Também se avaliou subjetivamente a sensação de saciedade e quantidade de alimento ingerido durante a 16ª semana de uso do dispositivo. RESULTADOS: Quando avaliadas médias de retenção, nota-se que, na 16ª semana de uso, há maior retenção para a primeira, segunda e quarta horas quando comparados ao baseline (1ª h 74 ± 16,3 % p=0,001, 2ª h 45 ± 25% p < 0,001; 4ª 15 ± 15,8% p < 0,001). Não há diferença estatística entre as retenções na 16ª semanas entre os pacientes que atingiram e os que não atingiram o controle do diabetes (p=0,73), entre os que perderam mais de 10% de peso e os que não perderam (p=0,275). Durante a 16ª semana de uso, 23 pacientes (92%) referiram maior sensação de saciedade precoce e maior saciação, e todos referiram comer em menor volume de em relação ao período prévio à colocação do dispositivo. CONCLUSÕES: O DTED causa lentificação no esvaziamento gástrico, reversível após sua retirada, porém esta alteração no esvaziamento gástrico, mesmo sendo sintomática, com aumento de saciedade e saciação, e com diminuição do volume de alimento ingerido, não tem relação com a perda de peso e melhora do diabetes / INTRODUCTION: Obesity is now considered a pandemic, with about 500 million obese worldwide, with about 2.8 million deaths per year. The gastric bypass surgery is an important treatment for obesity, however, not without risks. The temporary duodenal jejunal exclusion device - DTED (EndoBarrier ® Gastrointestinal Liner GIDynamics, Inc. Lexington, MA), presents itself as a new form of endoscopic treatment of obesity. Despite the good results, the mechanisms of action of DTED have not been studied, and the humoral changes and changes in gastric emptying promoted by the device maybe are the main mechanisms of action of the device. OBJECTIVE: To study the changes introduced by DTED in gastric emptying, and the relationship of these changes with clinical outcomes of weight loss and control of type 2 diabetes. METHODS: Twenty five obese patients with type 2 diabetes who used the DTED for a minimum of 16 weeks and maximum 24 weeks underwent a scintigraphic gastric emptying test, before, during the 16th week of treatment and after 4 weeks of withdrawal the DTED. Measurements of weight, glycated hemoglobin were obtained. The mean and standard deviation of gastric retention were obtained and compared between the three tests, and after, compared between patients who were and those who showed no improvement in selected clinical parameters (weight loss greater than 10%, and lower glycated hemoglobin 7%). Also, a subjective evaluation of the feeling of satiety and amount of food ingested during the 16 weeks of device use was done. RESULTS: When evaluated average retention , we note that in the 16th week of use there is greater retention for the first, second and fourth hour compared to baseline (1st h 74 ± 16.3 % p = 0.001, 2nd h 45 ± 25 % p < 0.001 4th 15.8 ± 15 %, p < 0.001). There is no statistical difference among patients who achieved and those who have not reached the control of diabetes (p = 0.73) or among those who lost more than 10 % by weight and not lost (p = . 0.275) during the 16th week of treatment , 23 patients (92%) reported greater sense of early satiety and satiation greater, and all reported eating less volume of food in relation to the period prior to devide placement. CONCLUSIONS: The DTED cause delay in gastric emptying, reversible after withdrawal, though this change in gastric emptying, even being symptomatic with increased satiety and satiation , decreasing the volume of food ingested , has no relation to weight loss and improved diabetes

O objetivo deste trabalho foi avaliar a aplicação clínica e a efetividade da coagulação com plasma de argônio(CPA) usada para realizar a ablação do esôfago de Barrett. A presença desta moléstia é considerada uma condição pré maligna com potencial para o desenvolvimento do adenocarcinoma de esôfago. Um estudo clínico prospectivo foi realizado com um grupo de 30 pacientes portadores de esôfago de Barrett, diagnosticado por meio de endoscopia digestiva alta e histologia. 25 pacientes eram do sexo masculino com idade variando entre 12 e 72 anos (média = 47,1) e 5 pacientes eram do sexo feminino cuja idade variou entre 45 e 60( média=49.9). Os pacientes eram submetidos à cirurgia antirefluxo e depois encaminhados para o tratamento com a CPA. O tratamento era realizado sob sedação em regime ambulatorial. Os pacientes eram submetidos a sessões com intervalos de 30 dias até obter o desaparecimento completo da lesão à endoscopia. Após três meses eram realizadas biópsias para o controle de cura. O tamanho médio da área aplicada mostrou correlação com a sintomatologia e o aparecimento de complicações.Uma área maior que quatro cm correlacionou-se positivamente com estas variáveis. O número médio de sessões foi de 1 a 6 (média=2,1). O tempo médio de seguimento variou entre 29 dias a 4 anos com média de 1 ano e 4 meses. Em dois casos houve presença de epitélio de Barrett sob o neo revestimento que foi tratado novamente com bom resultado. As complicações ocorreram em 2 casos (6,6%) de estenose de esôfago e um caso(3,3%) de pneumo mediastino todas tratadas com bons resultados. O índice de sucesso com ablação total foi de 93,4%. Não houve mortalidade neste estudo. / The aim of this study is to determine the effectiveness of the Argon Plasma Coagulation (APC) in ablation therapy of specialized columnar epithelium in Barrett´s esophagus. The presence of Barrett´s epithelium is considered a premalignant condition with potential development of adenocarcinoma. The incidence of esophageal adenocarcinoma has been rising for the past 3 decades A prospective study performed with a group of 30 patients(25 men/5 women) with 47 years mean age (range 12 to72) for the men and 49,9 years mean age ( range 45 to 60) for the women presented with Barrett´s esophagus demonstrated by endoscopy and histology.They were referred to us after antireflux surgery and were assimptomatic at the beginning of the study. Application of APC was carried out under sedation (midazolan and meperidine) with a gas flow of 2,5 l/min & 70 w. The Barrett\'s epithelium was coagulated from the most proximal to the gastrointestinal junction to the most distal limit. The maximum size treated each time was 4 cm long. Special care was taken on coagulation of the visible small islands of remaining intestinal metaplasia tissue. The treatment performed in large areas, bigger than 4 cm led to the increasing rate of complications and transient symptoms. The patients returned monthly to new session until complete ablation of the Barrett´s esophagus was showed by endoscopy. Then, 3 months later after that, a extensive random biopsies were taken to histology search for Barrett\'s. The mean number of APC sessions was 2,1 (range 1 to 6). In two cases, endoscopy showed absence of intestinal metaplasia but histology shows small islands of intestinal metaplasia under the neosquamous epithelium. Two(6,6%) esophageal stenosis and one (3,3%) pneumomediastin case have been occurred. The follow up ranged to 27days to 4 years (mean one year and four months). Reepitelialization with squamous epithelium indistinguishable of the esophageal mucosa was demonstrated by endoscopy in 93,4%. There has been no relapse or evidence of the development of dysplasia. No deaths or major complication occurred in this study.

蠕動是一種能夠幫助食物通過胃腸道以及促進胃腸道產生能動性的類似波浪的收縮運動。它由一種叫做Cajal (ICC)間質細胞的起搏器細胞產生的慢波所控制。ICCs亦幫助由腸神經系統(ENS)到平滑肌的信息傳導。嚙齒動物和人類實驗表明，老化所導致的ICC細胞數量下降和腸神經退化與排便睏難和便秘有關。通過研究ICC和ENS在正常老化情況下和加速膽碱能神經元喪失的阿爾茲海默症(AD)老鼠模型(Tg2576)中的變化，我們對治療神經退化性疾病也許會有新的認識。本課題的目的在于，研究老化情況下正常老鼠模型及澱粉樣前體蛋白質(APP)過量表達下的AD老鼠模型的胃腸道在形態及功能上的變化。 / 六個月大的Tg2576和同齡野生型對照的全樣載片免疫組化實驗顯示， 十二指腸 (P < 0.05)和迴腸 (P < 0.01)中的腸神經細胞顯著降低，迴腸 (P < 0.001)中的GFAP陽性的腸神經膠質細胞也顯著消失。S100陽性的腸神經膠質細胞在胃竇（胃部中的起搏區域）(P < 0.05), 迴腸 (P < 0.05)和結腸 (P < 0.05)中顯著喪失。這些結果表明，在早期的AD階段，ENS已經出現變質。ICC細胞數量在六個月大的Tg2576和同齡野生型對照的所有腸胃部分並沒有顯著性差異 (P > 0.05)。同時，早期AD階段的基本蠕動節奏也並沒有發生改變。除此之外，結腸和十二指腸的GFAP/S100陽性的腸神經膠質細胞比例並沒有顯著增加，表明在早期AD階段，可能出現了炎症。 / 利用石蠟切片進行β澱粉樣蛋白免疫組化，天狼猩紅溶液化驗和硫代黃素T溶液化驗可以測試不溶的澱粉樣斑塊是否存在。結果指出在六個月大的Tg2576所有腸胃部分都觀察到澱粉樣斑塊聚集而在不同的腸胃部分聚集的程度都有所分別。除了結腸外，六個月大的野生型對照所有腸胃部分都觀察不到澱粉樣斑塊聚集。澱粉樣斑塊形成的增長可能和早期AD階段出現的腸神經細胞和腸神經膠質細胞喪失互相關聯。 / 應用電泳轉移酶標免疫印斑技術，測試六個月大的Tg2576和同齡野生型對照的迴腸和結腸中，膽碱乙酰轉移酶 (ChAT，出自興奮神經元)， 神經元型一氧化氮合酶(nNOS，出自抑制神經元)， 膠質細胞源性神經營養因子 (GDNF， 出自腸神經膠質細胞)和可溶解的β澱粉樣蛋白寡聚體的表達是否改變。和野生型對照相比，Tg2576的nNOS的表達在迴腸 (P < 0.05) 而不是結腸 (P > 0.05) 中顯著增加。而ChAT，GDNF和各β澱粉樣蛋白寡聚體 (十二聚物，九聚物和六聚物)在六個月大的Tg2576和同齡野生型對照之間並沒有顯著改變 (P > 0.05)。綜上結果表明，在早期AD階段，腸胃道中的抑制信號有所增加，但是β澱粉樣蛋白寡聚體可能不是引致腸胃道中的腸神經細胞和腸神經膠質細胞喪失的原因。 / 在腸胃道的組織學和生化實驗之後，我們利用了微電極陣列 (MEA) 系統來量度出自胃竇和迴腸的慢波信號。量度出來的主導頻率(DF)和功率分佈可以成為測量在老化的ICR老鼠和早期AD階段下腸胃道的功能有沒有變化的參數。在硝苯地平存在下，尼古丁顯著地刺激三個月大 (P < 0.05) 和 六個月大 (P < 0.05) 的ICR老鼠中胃竇和迴腸的慢波活動但未能引起十二個月大 (P > 0.05) 的ICR老鼠中的慢波活動，說明神經退化可能在十二個月的年齡開始。附加了河豚毒素的情況下，尼古丁不能再刺激三個年齡組中胃竇和迴腸的慢波活動 (P > 0.05)，由此證明了尼古丁是對腸神經細胞起作用再去激發ICC的活動。六個月大的Tg2576和同齡野生型對照之間的胃竇和迴腸的基准讀數沒有顯著分別 (P > 0.05)。然而，尼古丁顯著地增加野生型對照中胃竇和迴腸的DF和胃電過速範圍 (P < 0.05) 但是不能刺激Tg2576中胃竇和迴腸的電流活動 (P > 0.05)，示意在早期AD階段腸胃道中已經出現了腸神經細胞和/或腸神經膠質細胞喪失。 / 綜上所言，研究結果提出AD老鼠模型有形態學，生物化學和功能上的轉變。本課題提供了在研究神經退化疾病上的基礎，也支持ENS是中樞神經系統早期病變前的關口這個假設。 / Peristalsis is the wave-like contraction that moves food along the gastrointestinal (GI) tract and generates GI motility. Peristalsis is modulated by slow waves that originate from pacemaker cells called interstitial cell of Cajal (ICC). ICCs also modulate and transduce inputs from the enteric nervous system (ENS) to the smooth muscle. Recent studies in rodents and humans demonstrated that a decrease in ICC number and enteric neurodegeneration during ageing is associated with difficult bowel movements and constipation. By studying ICC and the ENS during normal aging and in a mouse model (Tg2576) of Alzheimer’s disease (AD) where cholinergic loss may be exaggerated, we may gain new perspectives on the treatment of degenerative diseases. The aim of the present study therefore, was to investigate the morphological and functional changes of the GI tract of mice during ageing and in an AD mouse model over-expressing amyloid precursor protein (APP) using an isolated tissue approach. / Whole mount immunohistochemistry of 6-month-old Tg2576 mice and their age-matched wild type (WT) controls revealed that there were significant losses of enteric neurons in the duodenum (P < 0.05) and ileum (P < 0.001), and of GFAP-positive enteric glial cells in the ileum (P < 0.001). There was also a loss of S100-positive glial cells in the antrum (pacemaker region in the stomach) (P < 0.05), ileum (P < 0.05) and colon (P < 0.05). These results indicated the alteration of the ENS during the early stages of AD. There were no differences in ICC arears of all GI regions between 6-month-old Tg2576 mice and their age-matched WT controls (P > 0.05), and there was no alteration of basal peristaltic rhythm during the early stages of AD. The non-significant increase of GFAP to S100 enteric glial cell ratio in the duodenum and colon might indicate an ongoing inflammatory process in these two GI regions during the early stages of AD. / The presence of insoluble amyloid plaques was studied using Aβ immunohistochemistry, Sirius red assay and Thioflavin-T assay on paraffin wax sections. The aggregation of amyloid plaques was observed in all the GI regions of 6-month-old Tg2576 mice and the levels of amyloid plaque varied in different regions. No amyloid plaques were found in the GI tract of 6-month-old WT animals excepting the colon. The increase in formation of amyloid plaques might be correlated to the losses of enteric neurons and enteric glial cells during the early stages of AD. / Western blot analysis was performed on frozen sections of tissues from the ileum and colon to investigate whether there were changes in choline acetyltransferase (ChAT, from excitatory neurons), neuronal nitric oxide synthase (nNOS, from inhibitory neurons), glial cell line-derived neurotrophic factor (GDNF, from enteric glia) and soluble Aβ oligomers between 6-month-old Tg2576 mice and WT controls. nNOS expression significantly increased in the ileum (P < 0.05) but not in the colon (P > 0.05) of Tg2576 mice compared with WT controls. There were no differences in the expressions of ChAT, GDNF and Aβ oligomers (docecamer, nonamer and hexamer) in the ileum and colon between Tg2576 mice and WT controls (P > 0.05). These results imply that there is an increase in the inhibitory signal in the GI tract during the early stages of AD but soluble Aβ oligomers might not be the cause of neuronal and glial losses in the GI tract. / Following histological and biochemical studies of different GI regions, slow wave signals from the antrum and ileum were measured using a microelectrode array (MEA) system. The dominant frequencies (DFs) and power distributions were measured and these served as parameters for measuring functional changes in the GI tract during ageing in ICR mice and the early stages of AD. In the presence of nifedipine, nicotine significantly stimulated the slow wave activities in the antrum and ileum of 3-month-old (P < 0.05) and 6-month-old (P < 0.05) ICR mice but failed to trigger the slow wave activities in 12-month-old (P > 0.05) ICR mice, suggesting the neurodegeneration might begin with the age between 6 and 12 months. With the addition of tetrodotoxin, nicotine failed to stimulate the slow wave activities in the antrum and ileum of three age groups (P > 0.05) and it showed that nicotine only acted on enteric neurons to trigger the ICC activities. There were no differences in the antral and ileal baseline recordings between 6-month-old Tg2576 mice and their age-matched WT controls (P > 0.05). However, nicotine significantly increased DFs and tachygastria ranges of the antrum and ileum in WT controls (P < 0.05) but failed to increase electrical activitiy of the antrum and ileum in Tg2576 mice (P > 0.05), thus suggesting a loss of neuronal and/or glial cells in the GI tract during the early stages of AD. / In conclusions, these findings suggest the mouse model for AD has morphological, biochemical and functional changes in the GI tract. The present studies provide a foundation for the investigation of degenerative diseases and support the hypothesis that the ENS may be the gateway for the early pathological changes in the central nervous system. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Hui, Chin Wai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 180-200). / Abstracts also in Chinese. / PUBLICATIONS RELATED TO THE WORK IN THIS THESIS --- p.i / ABSTRACT --- p.ii / 摘要 --- p.iv / ACKNOWLEDGEMENTS --- p.vi / LIST OF ABBREVIATIONS --- p.vii / Chapter CHAPTER 1 --- Introduction --- p.1 / Chapter 1.1 --- General introduction --- p.1 / Chapter 1.2 --- Interstitial cells of Cajal (ICCs) as electrical pacemaker cells in GI tract --- p.1 / Chapter 1.2.1 --- ICC subtypes in GI tract --- p.2 / Chapter 1.3 --- Hypotheses of slow wave generation --- p.4 / Chapter 1.3.1 --- Mechanisms of the NSCC pacemaking hypothesis --- p.5 / Chapter 1.3.2 --- Mechanisms of the alternative hypothesis --- p.6 / Chapter 1.4 --- Involvement of ion channels in slow wave generation of ICC --- p.6 / Chapter 1.4.1 --- Calcium channels --- p.6 / Chapter 1.4.2 --- Sodium channels --- p.7 / Chapter 1.4.3 --- Potassium channels --- p.7 / Chapter 1.4.4 --- Chloride channels --- p.8 / Chapter 1.4.5 --- Non-selective cation channels --- p.8 / Chapter 1.5 --- Distribution of several types of receptors in ICC --- p.11 / Chapter 1.5.1 --- Purinergic receptors --- p.11 / Chapter 1.5.2 --- Muscarinic receptors --- p.11 / Chapter 1.5.3 --- Tachykinin receptors --- p.12 / Chapter 1.5.4 --- Vasoactive intestinal peptide receptors --- p.12 / Chapter 1.5.5 --- Serotonin receptors --- p.13 / Chapter 1.6 --- Introductions and functions of enteric nervous system --- p.15 / Chapter 1.6.1 --- Interaction amongst the central, peripheral and enteric nervous system: brain-gut axis --- p.15 / Chapter 1.6.2 --- Enteric neuronal subtypes in the GI tract --- p.15 / Chapter 1.6.2.1 --- Motor neurons --- p.16 / Chapter 1.6.2.2 --- Interneurons --- p.16 / Chapter 1.6.2.3 --- Intrinsic primary afferent neurons --- p.18 / Chapter 1.6.3 --- Enteric glial cells --- p.18 / Chapter 1.6.3.1 --- Enteric glial subtypes in the GI tract --- p.18 / Chapter 1.6.3.2 --- Communication between enteric neurons and glial cells --- p.19 / Chapter 1.6.3.3 --- Possible functions of enteric glial cells in the GI tract --- p.19 / Chapter 1.6.3.3.1 --- Secretion of neurotrophic factors --- p.20 / Chapter 1.6.3.3.2 --- Secretion of reduced glutathione --- p.20 / Chapter 1.6.3.3.3 --- Secretion of transforming growth factor-beta 1 --- p.21 / Chapter 1.7 --- Interactions amongst ICC, enteric neurons and enteric glial cells --- p.21 / Chapter 1.8 --- Gastrointestinal disorders --- p.22 / Chapter 1.8.1 --- Mechanisms for cell depletion --- p.22 / Chapter 1.8.1.1 --- Autoimmune attack --- p.22 / Chapter 1.8.1.2 --- Hyperglycaemia and diabetes mellitus --- p.24 / Chapter 1.8.1.3 --- Oxidative stress --- p.25 / Chapter 1.8.1.4 --- Ageing --- p.26 / Chapter 1.9 --- Alzheimer’s disease --- p.28 / Chapter 1.9.1 --- Genetics and pathogenesis of Alzheimer’s disease --- p.28 / Chapter 1.9.1.1 --- Aggregation of amyloid beta protein --- p.29 / Chapter 1.9.1.2 --- Genetic factors of AD --- p.29 / Chapter 1.9.1.3 --- Tau hyperphosphorylation and neurofibrillary tangles --- p.31 / Chapter 1.9.2 --- Current treatment for Alzheimer’s disease --- p.33 / Chapter 1.9.2.1 --- Symptomatic treatment --- p.33 / Chapter 1.9.2.2 --- Disease-modifying treatment --- p.34 / Chapter 1.9.2.3 --- Other potential drugs for AD treatment --- p.35 / Chapter 1.9.3 --- Possible animal models for AD investigation --- p.36 / Chapter 1.9.4 --- Possible correlations between Alzheimer’s disease and the enteric nervous system --- p.36 / Chapter 1.10 --- Aim of study --- p.37 / Chapter CHAPTER 2 --- Investigation into the morphologies of enteric nervous system and interstitial cell of Cajal in Tg2576 mice --- p.38 / Chapter 2.1 --- Introduction --- p.38 / Chapter 2.1.1 --- Molecular markers for ICC, ENC, and EGC --- p.38 / Chapter 2.1.2 --- Aims and objectives --- p.39 / Chapter 2.2 --- Materials and methods --- p.41 / Chapter 2.2.1 --- Animals --- p.41 / Chapter 2.2.2 --- Tissue preparation --- p.41 / Chapter 2.2.3 --- Immunohistochemistry --- p.42 / Chapter 2.2.4 --- Image acquisition and analysis --- p.43 / Chapter 2.3 --- Results --- p.44 / Chapter 2.3.1 --- General observations --- p.44 / Chapter 2.3.2 --- Area and pattern of ICCs and the ENS in the stomach --- p.46 / Chapter 2.3.3 --- Area and pattern of ICCs and the ENS in the duodenum --- p.52 / Chapter 2.3.4 --- Area and pattern of ICCs and the ENS in the jejunum --- p.56 / Chapter 2.3.5 --- Area and pattern of ICCs and the ENS in the ileum --- p.60 / Chapter 2.3.6 --- Area and pattern of ICCs and the ENS in the colon --- p.66 / Chapter 2.4 --- Discussion --- p.70 / Chapter 2.4.1 --- Major findings --- p.70 / Chapter 2.4.2 --- Possible alterations of the ENS during AD --- p.70 / Chapter 2.4.3 --- Morphological changes of the ENS in relation to genotype --- p.71 / Chapter 2.4.4 --- Morphological changes of ICCs in relation to genotype --- p.72 / Chapter 2.4.5 --- Morphological changes of the ENS and ICCs in relation to GI regions --- p.72 / Chapter 2.4.6 --- Inflammatory conditions in different GI regions --- p.73 / Chapter 2.5 --- Conclusion --- p.74 / Chapter CHAPTER 3 --- Formation of amyloid plaques in the brain and the GI tract of Tg2576 mice --- p.75 / Chapter 3.1 --- Introduction --- p.75 / Chapter 3.1.1 --- The absence of amyloid plaques in rodents --- p.75 / Chapter 3.1.2 --- Overexpression of human APP in transgenic mice --- p.76 / Chapter 3.1.3 --- Distribution of human APP and Aβ deposition in human and transgenic mice --- p.77 / Chapter 3.1.4 --- Transgene and promoter in Tg2576 mouse --- p.77 / Chapter 3.1.5 --- Methods for Aβ plaque detection --- p.78 / Chapter 3.1.6 --- Aim and objectives --- p.78 / Chapter 3.2 --- Materials and methods --- p.80 / Chapter 3.2.1 --- Animals --- p.80 / Chapter 3.2.2 --- Tissue processing --- p.80 / Chapter 3.2.3 --- Preparation of paraffin wax blocks and slide sections --- p.81 / Chapter 3.2.4 --- Aβ immunohistochemistry --- p.82 / Chapter 3.2.5 --- Sirius red assay --- p.83 / Chapter 3.2.6 --- Thioflavin-T assay --- p.84 / Chapter 3.2.7 --- Image acquisition --- p.84 / Chapter 3.3 --- Results --- p.85 / Chapter 3.3.1 --- Aβ immunohistochemistry --- p.85 / Chapter 3.3.1.1 --- The absence of positive immunoreactivity in the brain --- p.85 / Chapter 3.3.1.2 --- The presence of positive immunoreactivity in the GI tract of Tg2576 mice --- p.85 / Chapter 3.3.2 --- Sirius red assay --- p.92 / Chapter 3.3.2.1 --- The presence of positive immunoreactivity in the brain of Tg2576 mice --- p.92 / Chapter 3.3.2.2 --- Characteristics of Sirius red staining in the GI tract --- p.92 / Chapter 3.3.2.3 --- The presence of positive immunoreactivity in the GI tract of Tg2576 mice --- p.92 / Chapter 3.3.3 --- Thioflavin-T assay --- p.98 / Chapter 3.3.3.1 --- The presence of positive immunoreactivity in the brain of Tg2576 mice --- p.98 / Chapter 3.3.3.2 --- The presence of positive immunoreactivity in the GI tract of Tg2576 mice --- p.98 / Chapter 3.4 --- Discussion --- p.104 / Chapter 3.4.1 --- The presence of a small amount of amyloid plaques in the brain of young Tg2576 mice --- p.104 / Chapter 3.4.2 --- The presence of amyloid plaques in the GI tract --- p.104 / Chapter 3.4.3 --- Plaque formation in relation to genotype --- p.105 / Chapter 3.4.4 --- Possible effects of amyloid plaques in the brain and GI tract --- p.106 / Chapter 3.5 --- Conclusion --- p.108 / Chapter CHAPTER 4 --- Expression of Aβ oligomers, ChAT, nNOS and GDNF in the GI tract of Tg2576 mice --- p.109 / Chapter 4.1 --- Introduction --- p.109 / Chapter 4.1.1 --- Common and peripheral types of ChAT --- p.109 / Chapter 4.1.2 --- Three subtypes of NOS --- p.111 / Chapter 4.1.3 --- Functions of glial cell line-derived neurotrophic factor in the ENS --- p.112 / Chapter 4.1.4 --- Neurotoxicity of soluble Aβ peptides --- p.113 / Chapter 4.1.5 --- Aims and objectives --- p.113 / Chapter 4.2 --- Materials and methods --- p.115 / Chapter 4.2.1 --- Animals --- p.115 / Chapter 4.2.2 --- Preparation of materials --- p.115 / Chapter 4.2.3 --- Sample preparation --- p.117 / Chapter 4.2.4 --- Separating and stacking gels preparation --- p.118 / Chapter 4.2.5 --- Western blot --- p.119 / Chapter 4.2.6 --- Image acquisition and analysis --- p.120 / Chapter 4.3 --- Results --- p.122 / Chapter 4.3.1 --- Increase in nNOS expression in the ileum of Tg2576 mice --- p.122 / Chapter 4.3.2 --- No changes in the expressions of Aβ oligomers, ChAT, nNOS and GDNF in the colon of Tg2576 mice --- p.122 / Chapter 4.4 --- Discussion --- p.127 / Chapter 4.4.1 --- The absence of “cholinergic hypothesis of AD in the GI tract of Tg2576 mice --- p.127 / Chapter 4.4.2 --- Increased expression of nNOS in the ileum of Tg2576 mice --- p.128 / Chapter 4.4.3 --- Neuronal and glial losses may be related to the reduced GDNF expression --- p.129 / Chapter 4.4.4 --- No relationship between the Aβ oligomers and neuronal damages in the GI tract --- p.129 / Chapter 4.5 --- Conclusion --- p.129 / Chapter CHAPTER 5 --- Microelectrode array (MEA) study on slow wave activity in the GI tract --- p.131 / Chapter 5.1 --- Introduction --- p.131 / Chapter 5.1.1 --- Components in peristalsis-controlling unit --- p.131 / Chapter 5.1.2 --- Techniques in evaluating slow wave activity --- p.131 / Chapter 5.1.2.1 --- Patch clamp --- p.132 / Chapter 5.1.2.2 --- Calcium imaging --- p.132 / Chapter 5.1.3 --- Application of microelectrode array in evaluating slow wave activity --- p.134 / Chapter 5.1.4 --- Aims and objectives --- p.136 / Chapter 5.2 --- Methods and materials --- p.137 / Chapter 5.2.1 --- Animals --- p.137 / Chapter 5.2.2 --- Tissue preparation --- p.137 / Chapter 5.2.3 --- Electrical recordings --- p.138 / Chapter 5.2.4 --- Analysis and Statistics --- p.139 / Chapter 5.3 --- Results --- p.142 / Chapter 5.3.1 --- Experiments on ICR mice --- p.142 / Chapter 5.3.1.1 --- Nicotine stimulates the slow wave activity in the antrum in the presence of NIF but not in the presence of NIF and 500 nM TTX --- p.142 / Chapter 5.3.1.2 --- Nicotine stimulates the slow wave activity in the ileum in the presence of NIF but only partially stimulates activity in the presence of NIF and 500 nM TTX --- p.152 / Chapter 5.3.1.3 --- The use of 1 μM TTX completely blocked the nicotine stimulation in the ileum --- p.160 / Chapter 5.3.1.4 --- The dominant frequency of baseline increased in the ileum of 12-month-old ICR but not in the antrum in the presence of NIF --- p.162 / Chapter 5.3.2 --- Experiments on Tg2576 mice and their wild type controls --- p.164 / Chapter 5.3.2.1 --- No differences in both antral and ileal baseline DFs between 6- month-old non-transgenic and Tg2576 mice --- p.164 / Chapter 5.3.2.2 --- Nicotine stimulates slow wave activity in the antrum of 6-month-old wild type controls but not of Tg2576 mice --- p.164 / Chapter 5.3.2.3 --- Nicotine stimulates slow wave activity in the ileum of 6-month-old wild type controls but not of Tg2576 mice --- p.167 / Chapter 5.4 --- Discussion --- p.171 / Chapter 5.4.1 --- Pharmacological effects of nicotine in the GI tract --- p.171 / Chapter 5.4.2 --- Excitatory effects of nicotine in the slow wave activities of the stomach and ileum --- p.172 / Chapter 5.4.3 --- Changes of ICC functions and neuronal activities during ageing --- p.174 / Chapter 5.4.4 --- Enteric neurodegeneration leads to alteration in the ENS function in Tg2576 mice --- p.175 / Chapter 5.4.5 --- Conclusion --- p.176 / Chapter CHAPTER 6 --- Concluding discussion --- p.177 / REFERENCES --- p.180

INTRODUÇÃO: A fistula esofagorrespiratória é complicação temida do câncer esofágico avançado. A paliação com prótese metálica autoexpansível é método amplamente empregado, porém com resultados conflitantes. OBJETIVO: Identificar fatores associados ao insucesso clínico do tratamento da fístula esofagorrespiratória maligna com prótese metálica autoexpansível. MÉTODOS: Estudo retrospectivo através da análise de banco de dados elaborado de forma prospectiva de pacientes submetidos ao tratamento da fístula esofagorrespiratória maligna com prótese metálica autoexpansível entre janeiro de 2009 e fevereiro de 2016 em hospital terciário dedicado ao tratamento do câncer. Foram coletados dados quanto à: características demográficas, nível de albumina sérica, capacidade funcional do paciente, doença pulmonar infecciosa em atividade no momento da passagem da prótese, tratamentos oncológicos prévios, momento do diagnóstico da fístula, tamanho e localização do trajeto fistuloso. RESULTADOS: Um total de 71 pacientes foram incluídos no estudo (55 homens, idade média de 59 anos). Insucesso clínico ocorreu em 44.3% dos pacientes. ECOG 3 ou 4, desenvolvimento da fístula durante o tratamento do câncer esofágico e diâmetro da fístula >= 1 cm foram fatores preditivos do insucesso clínico. ECOG 3 ou 4, doença pulmonar infecciosa em atividade no momento da passagem da prótese e tratamento oncológico prévio com radioterapia foram fatores preditivos de menor sobrevida. O grau de disfagia melhorou significativamente 15 dias após a passagem da prótese. A taxa total de eventos adversos foi de 30%. Migração da prótese e a oclusão da mesma por crescimento tumoral nas extremidades da prótese foram os eventos adversos mais comumente observados. CONCLUSÃO: A prótese metálica autoexpansível é um método terapêutico efetivo para o tratamento da fístula esofagorrespiratória maligna, no entanto, ECOG 3 ou 4, desenvolvimento da fístula durante o tratamento do câncer esofágico e diâmetro da fístula >= 1cm foram fatores preditivos do insucesso clínico após a passagem da prótese / INTRODUCTION: Malignant esophagorespiratory fistula is a serious and life-threatening complication of esophageal cancer. Self-expandable metal stents placement is a well accepted palliative treatment, however, with conflicting results. OBJECTIVE: To identify risk factors associated with clinical failure after self-expandable metal stents placement for the treatment of malignant esophagorespiratory fistula. METHODS: This was a retrospective analysis of a prospectively maintained database used at a tertiary cancer hospital, with patients treated with SEMS placement for MERF between January 2009 and February 2016. The following variables were collected: patient demographics, serum albumin level, Eastern Cooperative Oncology Group (ECOG) performance status, pulmonary infection, previous oncologic treatment, moment of diagnosis of the malignant esophagorespiratory fistula, size and classification of the fistulous tract. RESULTS: A total of 71 patients (55 males, mean age 59 years) were considered for the final analysis. Clinical failure occurred in 44.3% of the patients. ECOG 3 or 4, fistula development during esophageal cancer treatment and fistula diameter >= 1cm were factors associated with increased risk of clinical failure. ECOG 3 or 4, pulmonary infection at the time of SEMS placement and prior radiation therapy were predictive factors associated with lower overall survival. Dysphagia scores improved significantly 15 days after stent insertion. The overall stent-related adverse events rate was 30%. Stent migration and occlusion due to tumor overgrowth were the most commonly seen adverse events. CONCLUSION: SEMS placement is a reasonable treatment option for MERF, however, ECOG 3 or 4, fistula development during esophageal cancer treatment or large fistula diameter may be independent predictors of clinical failure after stenting

Ο φαρμακευτικός κλάδος μπορεί να επωφεληθεί, με την βοήθεια της σημερινής τεχνολογίας των ηλεκτρονικών υπολογιστών και συγκεκριμένα των βάσεων δεδομένων. Σκοπός της διπλωματικής εργασίας είναι η κάλυψη των αναγκών της Ελληνικής συνταγογραφίας των φαρμάκων. Συγκεκριμένα οι φαρμακευτικές βάσεις δεδομένων, που ήδη υπάρχουν, δεν χρησιμοποιούν την τεχνολογία αναζήτησης των αλληλεπιδράσεων των φαρμάκων. Για το σκοπό αυτό σχεδιάστηκε και υλοποιήθηκε ένα μοντέλο βάσεων δεδομένων, που υποστηρίζει πλήρως τις αλληλεπιδράσεις των φαρμάκων, σύμφωνα με τις οδηγίες του εθνικού συνταγολογίου φαρμάκων (Ε.Ο.Φ). Έπειτα έγινε η εισαγωγή των φαρμάκων και δοκιμάστηκε η ακεραιότητα του συστήματος για την επιτυχή λειτουργία των αλληλεπιδράσεων μεταξύ φαρμάκων, καθώς μια εσφαλμένη αλληλεπίδραση μπορεί να αποβεί μοιραία για κάποιους ασθενείς. Τέλος αυτή η διπλωματική εργασία μπορεί να χρησιμοποιηθεί από φαρμακοποιούς και ιατρούς για την ασφαλέστερη και αποτελεσματικότερη συνταγογράφηση. / The pharmaceutical branch can profit, with the help of current technology of computers and concretely with the use of data bases. The purpose of this diplomatic work is to cover the needs of the Greek prescription on medicines. Particularly the pharmaceutical data bases, that already exist, do not use the search technology of interactions in medicines. For this aim it was drawn and implemented a model of data bases, that completely supports the interactions of medicines, according to the directives of national organization for medicines (N.O.M). The next step was the insertion of medicines and test the integrity of system for the successful operation of interactions between medicines, while a mistaken in interaction it can be turns out fatal for certain patients. Finally this diplomatic work can be used from pharmacists and doctors for secure and more effective prescription.

Background: The endocrine pancreas contains multiple cell types co-localized into clusters called the Islets of Langerhans. The predominant cell types include alpha and beta cells, which produce glucagon and insulin, respectively. The regulated release of these hormones maintains whole body glucose homeostasis, essential for normal metabolism and to prevent diabetes and complications from the disease. Given the heterogeneous nature of islet composition and absence of unique surface markers, many previous studies have focused on the whole islet. Sorting islet cells by intracellular hormone expression overcomes this limitation and provides pure populations of individual islet cell subsets, specifically alpha and beta cells. This technique provides the framework for characterizing human islet composition and will work towards identifying the genetic changes alpha and beta cells undergo during development, growth, and proliferation. Methods: Human islets obtained from cadaveric donors are dissociated into a single cell suspension, fixed, permeabilized, and labeled with antibodies specific to glucagon, insulin, and somatostatin. Individual alpha, beta, and delta cell populations are simultaneously isolated using fluorescence activated cell sorting. Candidate gene expression and microRNA profiles have been obtained for alpha and beta cell populations using a quantitative nuclease protection assay. Thus far, RNA has been extracted from whole islets and beta cells and subjected to next generation sequencing analysis. Results: The ratio of beta to alpha cells significantly increases with donor age and trends higher in female donors; BMI does not appear to significantly alter the ratio. Further, we have begun to investigate the unique gene expression profiles of alpha and beta cells versus whole islets, and have characterized the microRNA profiles of the two cell subsets. Conclusions: By establishing methods to profile multiple characteristics of alpha and beta cells, we hope to determine how gene, miRNA, and protein expression patterns change under environmental conditions that lead to beta cell failure or promote beta cell development, growth, and proliferation.

Protein folding in the endoplasmic reticulum (ER) is essential for proper cellular function. However, the sensitive environment in the ER can be perturbed by both pathological processes as well as by physiological processes such as a large biosynthetic load placed on the ER. ER stress is a specific type of intracellular stress caused by the accumulation of immature or abnormal misfolded or unfolded proteins in the ER. Simply defined, ER stress is a disequilibrium between ER load and folding capacity. Cells have an adaptive response that counteracts ER stress called the "Unfolded Protein Response” (UPR). The ability to adapt to physiological levels of ER stress is especially important for maintaining ER homeostasis in secretory cells. This also holds true for pancreatic β-cells, which must fold and process large amounts of the hormone insulin. Pancreatic β-cells minimize abnormal levels of glycemia through adaptive changes in the production and regulated secretion of insulin. This process is highly sensitive, so that small degrees of hypo- or hyperglycemia result in altered insulin release. The frequent fluctuation of blood glucose levels in humans requires that β-cells control proinsulin folding in the ER with exquisite sensitivity. Any imbalance between the load of insulin translation into the ER and the actual capacity of the ER to properly fold and process the insulin negatively affects the homeostasis of β-cells and causes ER stress. In this dissertation, we show that Inositol Requiring 1 (IRE1), an ER-resident kinase/endoribonuclease and a central regulator of ER stress signaling, is essential for maintaining ER homeostasis in pancreatic β-cells. Importantly, IRE1 has a crucial function in the body’s normal production of insulin in response to high glucose. Phosphorylation and subsequent activation of IRE1 by transient exposure to high glucose is coupled to insulin biosynthesis, while inactivation of IRE1 by siRNA or inhibition of IRE1 phosphorylation abolishes insulin biosynthesis. IRE1 signaling under these physiological ER stress conditions utilizes a unique subset of downstream components of IRE1 and has a beneficial effect on pancreatic β-cell homeostasis. In contrast, we show that chronic exposure of β-cells to high glucose causes pathological levels of ER stress and hyperactivation of IRE1, leading to the degradation of insulin mRNA. The term “glucose toxicity” refers to impaired insulin secretion by β-cells in response to chronic stimulation by glucose and is characterized by a sharp decline in insulin gene expression. However, the molecular mechanisms of glucose toxicity are not well understood. We show that hyperactivation of IRE1 caused by chronic high glucose treatment or IRE1 overexpression leads to insulin mRNA degradation in pancreatic β-cells. Inhibition of IRE1 signaling using a dominant negative form of the protein prevents insulin mRNA degradation in β-cells. Additionally, islets from mice heterozygous for IRE1 retain expression of more insulin mRNA after chronic high glucose treatment than do their wild-type littermates. This work suggests that the rapid degradation of insulin mRNA could provide immediate relief for the ER and free up the translocation machinery. Thus, this mechanism may represent an essential element in the adaptation of β-cells to chronic hyperglycemia. This adaptation is crucial for the maintenance of β-cell homeostasis and may explain in part why the β-cells of diabetic patients with chronic hyperglycemia stop producing insulin without simply undergoing apoptosis. This work implies that prolonged activation of IRE1 signaling is involved in the molecular mechanisms underlying glucose toxicity. This work therefore reveals two distinct activities elicited by IRE1 in pancreatic β-cells. IRE1 signaling activated by transient exposure to high glucose enhances proinsulin biosynthesis, while chronic exposure of β-cells to high glucose causes hyperactivation of IRE1, leading to the degradation of insulin mRNA. Physiological IRE1 activation by transient high glucose levels in pancreatic β cells has a beneficial effect on insulin biosynthesis. However, pathological IRE1 activation by chronic high glucose or experimental drugs negatively affects insulin gene expression. In the future, a system to induce a physiological level of IRE1 activation, and/or reduce the pathological level of IRE1 activation could be used to enhance insulin biosynthesis and secretion in people with diabetes, and may lead to the development of new and more effective clinical approaches to the treatment of this disorder.

INTRODUÇÃO: Obesidade é, hoje, considerada uma pandemia, com cerca de 500 milhões de obesos no mundo, com cerca de 2,8 milhões de mortes por ano. A cirurgia de bypass gástrico é um importante tratamento para obesidade, porém, não é isenta de riscos. O dispositivo temporário de exclusão duodeno jejunal - DTED (EndoBarrier Gastrointestinal Liner® GIDynamics, Inc. Lexington, MA), apresenta-se como uma nova forma de tratamento endoscópico da obesidade. Apesar dos bons resultados, os mecanismos de ação do DTED ainda não foram estudados, podendo as alterações humorais e do esvaziamento gástrico promovidas, ser os principais responsáveis pelos resultados obtidos. OBJETIVO: Estudar as alterações promovidas pelo DTED no esvaziamento gástrico, e a relação destas alterações com os resultados clínicos de perda de peso e controle do diabetes tipo 2. MÉTODOS: Vinte e cinco obesos e com diabetes tipo 2, que fizeram uso do DTED por período mínimo de 16 semanas e máximo de 24 semanas, realizaram teste de esvaziamento gástrico cintilográfico, antes, durante a 16ª semana de uso e após 4 semanas de retirada do DTED. Foram obtidas medidas de peso e hemoglobina glicada. As médias e desvio-padrão de retenção gástricas foram obtidas e comparadas entre os três exames realizados, e, após, comparados entre os pacientes que obtiveram e os que não obtiveram melhora no parâmetro clínico selecionado (perda de peso maior que 10%, e hemoglobina glicada menor que 7%). Também se avaliou subjetivamente a sensação de saciedade e quantidade de alimento ingerido durante a 16ª semana de uso do dispositivo. RESULTADOS: Quando avaliadas médias de retenção, nota-se que, na 16ª semana de uso, há maior retenção para a primeira, segunda e quarta horas quando comparados ao baseline (1ª h 74 ± 16,3 % p=0,001, 2ª h 45 ± 25% p < 0,001; 4ª 15 ± 15,8% p < 0,001). Não há diferença estatística entre as retenções na 16ª semanas entre os pacientes que atingiram e os que não atingiram o controle do diabetes (p=0,73), entre os que perderam mais de 10% de peso e os que não perderam (p=0,275). Durante a 16ª semana de uso, 23 pacientes (92%) referiram maior sensação de saciedade precoce e maior saciação, e todos referiram comer em menor volume de em relação ao período prévio à colocação do dispositivo. CONCLUSÕES: O DTED causa lentificação no esvaziamento gástrico, reversível após sua retirada, porém esta alteração no esvaziamento gástrico, mesmo sendo sintomática, com aumento de saciedade e saciação, e com diminuição do volume de alimento ingerido, não tem relação com a perda de peso e melhora do diabetes / INTRODUCTION: Obesity is now considered a pandemic, with about 500 million obese worldwide, with about 2.8 million deaths per year. The gastric bypass surgery is an important treatment for obesity, however, not without risks. The temporary duodenal jejunal exclusion device - DTED (EndoBarrier ® Gastrointestinal Liner GIDynamics, Inc. Lexington, MA), presents itself as a new form of endoscopic treatment of obesity. Despite the good results, the mechanisms of action of DTED have not been studied, and the humoral changes and changes in gastric emptying promoted by the device maybe are the main mechanisms of action of the device. OBJECTIVE: To study the changes introduced by DTED in gastric emptying, and the relationship of these changes with clinical outcomes of weight loss and control of type 2 diabetes. METHODS: Twenty five obese patients with type 2 diabetes who used the DTED for a minimum of 16 weeks and maximum 24 weeks underwent a scintigraphic gastric emptying test, before, during the 16th week of treatment and after 4 weeks of withdrawal the DTED. Measurements of weight, glycated hemoglobin were obtained. The mean and standard deviation of gastric retention were obtained and compared between the three tests, and after, compared between patients who were and those who showed no improvement in selected clinical parameters (weight loss greater than 10%, and lower glycated hemoglobin 7%). Also, a subjective evaluation of the feeling of satiety and amount of food ingested during the 16 weeks of device use was done. RESULTS: When evaluated average retention , we note that in the 16th week of use there is greater retention for the first, second and fourth hour compared to baseline (1st h 74 ± 16.3 % p = 0.001, 2nd h 45 ± 25 % p < 0.001 4th 15.8 ± 15 %, p < 0.001). There is no statistical difference among patients who achieved and those who have not reached the control of diabetes (p = 0.73) or among those who lost more than 10 % by weight and not lost (p = . 0.275) during the 16th week of treatment , 23 patients (92%) reported greater sense of early satiety and satiation greater, and all reported eating less volume of food in relation to the period prior to devide placement. CONCLUSIONS: The DTED cause delay in gastric emptying, reversible after withdrawal, though this change in gastric emptying, even being symptomatic with increased satiety and satiation , decreasing the volume of food ingested , has no relation to weight loss and improved diabetes