No description available.

The use of adult hepatic stem cells for the treatment of diabetes, based both on the close embryological association of the pancreas and liver, and on a putative shared tissue stem cell, has been proposed by a number of studies. This study investigated the capacity of hepatic oval cells to differentiate into pancreatic endocrine cells in the presence of pancreatic mesoderm. The GaIN model of hepatic injury was used to induce oval cell activation in Male Sprague-Dawley rats. A viable and significant oval cell population could not however, be isolated and propagated in culture. In order to continue experimentation, a PHeSC-A2 cell line, derived from normal adult porcine liver, was cultured with quail pancreatic mesoderm in the GFRM-Ham s F12.ITS culture system. Cells demonstrating positive immulocalization of the pancreatic markers, insulin and glucagon, were identified as PHeSC-A2-derived, by visual assessment of their nuclear morphology. Techniques used to confirm these results and preclude the derivation of the pancreatic endocrine cells from pancreatic endodermal contamination, proved ineffectual. The tentative results obtained in this study have lead to the following postulations: firstly, the PHeSC-A2 cell line may possess a higher level of potentiality than previously demonstrated; secondly, this potential may be due to the shared embryological origins of the pancreas and liver, and thirdly, permissive signaling from pancreatic mesoderm may have the capacity to induce the differentiation of hepatic oval cells into pancreatic endocrine cells. Further research is required to confirm the results obtained in this study and to substantiate the aforementioned propositions.

Made available in DSpace on 2015-03-26T13:47:25Z (GMT). No. of bitstreams: 1 texto completo.pdf: 795172 bytes, checksum: d8766c35c169f6531bce61562c21c96d (MD5) Previous issue date: 2003-08-29 / The capybara, an herbivorous rodent of simple stomach, has been pointed out in the market of meats for having an excellent zootechnical performance. It has appreciated meat, valuable carcass, high reproductive potential and presents efficient food usage. The last item must be a consequence of the cecotrophy, which makes the cecum, an important organ in the digestive physiology of such animal. To carry out this study, ten adult capybaras from Cachoeirinhas` Farm in Viçosa-MG, were used. From them it was obtained data regarding the anatomy, histology and quantification of endocrine cells and nervous ganglia of the cecum. Fragments of the apex, body and base of the cranial taenia and of the area of ileocecal transition were collected. Macroscopically, the cecum is voluminous, sacciform, presenting a medium volumetrical capacity of 3,6 ± 1,7 l, and a medium length of 70 ± 16,2 cm completing a total of 25% of whole large intestine that measured 2,8 ± 0,6 m on the average. The cecum histologically showed straight tubulous glands with average length of 0,2 ± 0,02 mm, of prismatic simple mucous secretor epithelium, a highly vascularized submucosal tunic with nervous ganglia observed clearly, a developed and with numerous myenterics ganglia muscular tunic. Quantitatively, the cecum presented a medium number of 2,0 ± 1,0 submucosals ganglia/mm2, 6,7 ± 3,0 myenterics ganglia/mm2, 173,1 ± 60,8 argyrophylics cells/mm2, 207,8 ± 68,3 argentaffins cells/mm2 and 55,7 ± 27,4 serotonin immunoreactive cells/mm2. / A capivara, um roedor herbívoro de estômago simples, vem sendo apontada no mercado de carnes por ter um excelente desempenho zootécnico. Sua carne é apreciada e sua carcaça valiosa, apresenta elevado potencial reprodutivo e manifesta eficiente aproveitamento dos alimentos. Este, provavelmente seja conseqüência da realização da cecotrofia, que faz do ceco, importante órgão na fisiologia digestiva deste animal. Neste trabalho, utilizaram-se dez capivaras adultas, provenientes do criatório da Fazenda Cachoeirinha localizada no município de Viçosa-MG, das quais obtiveram-se dados a respeito da anatomia, histologia e quantificação de células endócrinas e gânglios nervosos do ceco. Foram coletados fragmentos do ápice, corpo, base, da tênia cranial e da região de transição íleo-cecal. Macroscopicamente, o ceco é volumoso, saculado, apresentando capacidade volumétrica média de 3,6 ± 1,7 l e comprimento médio de 70 ± 16,2 cm correspondente a 25% do intestino grosso com média de 280 ± 60 cm. Histologicamente, o ceco apresentou glândulas simples tubulosas de tamanho médio de 0,2 ± 0,02 mm, com epitélio simples cilíndrico secretor de muco, uma única submucosa altamente vascularizada contendo gânglios nervosos de fácil visualização, uma túnica muscular desenvolvida e com numerosos gânglios mioentéricos. Quantitativamente o ceco apresentou um número médio de 2,0 ± 1,0 gânglios submucosos/mm2, 6,7 ± 3,0 gânglios mioentéricos/mm2, 173,1 ± 60,8 células argirófilas/mm2, 207,8 ± 68,3 células argentafins/mm2 e 55,7 ± 27,4 células imunorreativas à serotonina/mm2.

京都大学 / 0048 / 新制・論文博士 / 博士(医学) / 乙第13377号 / 論医博第2211号 / 新制||医||1047(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 長船 健二, 教授 妹尾 浩, 教授 稲垣 暢也 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM

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No description available.

Studies on pancreatic cell physiology rely on the investigation of exocrine and endocrine cells in vitro. Particularly, in the case of the exocrine tissue these studies have suffered from a reduced functional viability of acinar cells in culture. As a result not only investigations on dispersed acinar cells and isolated acini were limited in their potential, but also prolonged studies on pancreatic exocrine and endocrine cells in an intact pancreatic tissue environment were unfeasible. To overcome these limitations, we aimed to establish a pancreas tissue slice culture platform to allow long-term studies on exocrine and endocrine cells in the intact pancreatic environment. Mouse pancreas tissue slice morphology was assessed to determine optimal long-term culture settings for intact pancreatic tissue. Utilizing optimized culture conditions, cell specificity and function of exocrine acinar cells and endocrine beta cells were characterized over a culture period of 7 days. We found pancreas tissue slices cultured under optimized conditions to have intact tissue specific morphology for the entire culture period. Amylase positive intact acini were present at all time points of culture and acinar cells displayed a typical strong cell polarity. Amylase release from pancreas tissue slices decreased during culture, but maintained the characteristic bell-shaped dose-response curve to increasing caerulein concentrations and a ca. 4-fold maximal over basal release. Additionally, endocrine beta cell viability and function was well preserved until the end of the observation period. Our results show that the tissue slice culture platform provides unprecedented maintenance of pancreatic tissue specific morphology and function over a culture period for at least 4 days and in part even up to 1 week. This analytical advancement now allows mid -to long-term studies on the cell biology of pancreatic disorder pathogenesis and therapy in an intact surrounding in situ.

White adipose plays a major role in the regulation of whole body metabolism through the storage and hydrolysis of triglycerides and by secretion of adipokines. The function of endocrine cells is highly dependent on the unfolded protein response (UPR), a homeostatic signaling mechanism that balances the protein folding capacity of the endoplasmic reticulum (ER) with the cell's secretory protein load. Here we demonstrate that the adipocyte UPR pathway is necessary for its secretory functions, and can thus play a crucial role in the control of whole body energy homeostasis. ER protein folding capacity is dependent both on the number of available chaperones as well as on their activity, which requires a sufficient ATP supply. In 3T3-L1 adipocytes, mitochondrial biogenesis occurred in parallel with induction of the UPR; therefore, we tested whether it was necessary for efficient ER function. Inhibition of mitochondrial ATP synthesis through depletion of Tfam, a mitochondrial transcription factor, or treatment with inhibitors of oxidative phosphorylation, demonstrate that ER function is sensitive to acute changes in adenine nucleotide levels. In addition, adenylate kinase 2 (AK2), which regulates mitochondrial adenine nucleotide interconversion, is markedly induced during adipocyte and B cell differentiation. AK2 depletion impairs induction of the UPR and secretion in both cell types. Interestingly, cytosolic adenylate kinase 1 (AK1) does not have the same effect upon UPR induction. We show that adenine nucleotides promote proper ER function and alterations in specific aspects of ATP synthesis can impair UPR signaling. Understanding the complex energetic regulation of the UPR may provide insight into the relationship between UPR and disease.

But de l’étudeL’atrésie intestinale est une anomalie congénitale définie par une perte de la continuité digestive. Malgré une restauration chirurgicale précoce de cette continuité, surviennent durant les premiers mois de vie des troubles de la motilité digestive et des surinfections bactériennes chez un tiers des patients. Ces troubles fonctionnels étaient attribués jusque là principalement à des altérations du système nerveux entérique. Le but de cette étude était de confirmer cette hypothèse mais également d’élargir le champ des explorations aux autres composants du tube digestif.Matériel et méthodesLe modèle animal de l’atrésie chez le rat initialement décrit dans notre équipe a été utilisé pour caractériser les anomalies d’expression génique par transcriptomique. L’étude portait également sur la maturation digestive chez des fœtus de rat contrôle entre un stade de développement embryonnaire E15 et E21. Des modifications en amont et en aval de l’obstruction ont été étudiées en prélevant deux segments successifs de 1 cm par cette approche globale transcriptomique puis précisées par RT-PCRq et confirmées par des techniques immunohistochimiques et de microscopie électronique. RésultatsChez les fœtus témoins, l’expression génique montre une décroissance physiologique pour le SNE et une augmentation pour les systèmes neuroendocrine et épithélial de E15 à E21. Concernant les fœtus avec atrésie, les modifications concernent quasi exclusivement le segment d’amont avec une augmentation du calibre intestinal, de l’épaisseur musculaire et une accélération globale de la maturation. Une redistribution des sous types neuronaux est constatée dans le segment d’amont ainsi qu’une augmentation de l’expression du système neuro endocrine. Pour ces deux systèmes, le segment d’aval est peu modifié. Des modifications importantes du système épithélial sont observées en amont comme en aval avec pour conséquence probable une altération de la barrière intestinale et du système anti infectieux.ConclusionCes résultats montrent que les changements prédominent dans le segment en amont de l’atrésie alors que le segment d’aval était parfois considéré comme le plus pathologique. De plus, il a été retrouvé des changements inattendus du système neuroendocrine et épithélial qui sous tendent une implication non exclusive du SNE. D’autres recherches sont nécessaires pour confirmer ces données et les exploiter dans une démarche thérapeutique. / Aim of the studyIntestinal atresia is a rare congenital affection with postoperative motility disorders, leading sometimes to death. Previous related studies mainly focused on enteric nervous system (ENS) alterations as it was identified to cause abnormal peristalsis. The aim of the study was to expertise the underlying pathological conditions of intestinal atresia using a global approach, before focusing on ENS and neuroendocrine cells in order to precise the presumptive involvement of the different layers of the intestinal wall.MethodsPreliminary transcriptomic approach was elected to screen global gene expression involved in intestinal development and atresia-linked disorders in the rat model previously described by our team. Rat embryos were assigned to atretic group and controls embryos at different stages of development ED15, ED17, ED19 and ED21. Two successive intestine samples of 1 cm were harvested in the proximal segment and in the distal one. The pattern of gene expression was further assessed by immunohistochemistry, electron microscopy and RT-qPCR. Main resultsA physiological decrease in gene expression for enteric nervous system markers and an increase for neuroendocrine and epithelial system was observed on controls from stages ED15 to ED21. Regarding affected embryos, structural modifications concerned the proximal segment with increased muscular layer and a significant disruption including global accelerated maturation was observed in the proximal segment with increased gene expression of neuroendocrine system. Distal segment was comparable to controls for the two systems. Important modifications were noted concerning the epithelial system with consequent abnormalities of the gut barrier and anti infectious functions.ConclusionsFetal intestinal obstruction results in a disrupted gut development predominant in the proximal segment. The distal segment and the ENS were poorly concerned by theses changes. Neuroendocrine and epithelial cells underwent significant unexpected changes, supporting the evidence that ENS do not play an exclusive role in the pathways of intestinal motility disorders.

Studies on pancreatic cell physiology rely on the investigation of exocrine and endocrine cells in vitro. Particularly, in the case of the exocrine tissue these studies have suffered from a reduced functional viability of acinar cells in culture. As a result not only investigations on dispersed acinar cells and isolated acini were limited in their potential, but also prolonged studies on pancreatic exocrine and endocrine cells in an intact pancreatic tissue environment were unfeasible. To overcome these limitations, we aimed to establish a pancreas tissue slice culture platform to allow long-term studies on exocrine and endocrine cells in the intact pancreatic environment. Mouse pancreas tissue slice morphology was assessed to determine optimal long-term culture settings for intact pancreatic tissue. Utilizing optimized culture conditions, cell specificity and function of exocrine acinar cells and endocrine beta cells were characterized over a culture period of 7 days. We found pancreas tissue slices cultured under optimized conditions to have intact tissue specific morphology for the entire culture period. Amylase positive intact acini were present at all time points of culture and acinar cells displayed a typical strong cell polarity. Amylase release from pancreas tissue slices decreased during culture, but maintained the characteristic bell-shaped dose-response curve to increasing caerulein concentrations and a ca. 4-fold maximal over basal release. Additionally, endocrine beta cell viability and function was well preserved until the end of the observation period. Our results show that the tissue slice culture platform provides unprecedented maintenance of pancreatic tissue specific morphology and function over a culture period for at least 4 days and in part even up to 1 week. This analytical advancement now allows mid -to long-term studies on the cell biology of pancreatic disorder pathogenesis and therapy in an intact surrounding in situ.