La régénération osseuse guidée (ROG) est une technique couramment utilisée pour la régénération de perte de substance osseuse. Elle repose sur l’utilisation d’une membrane jouant un rôle de « barrière » en isolant le défaut osseux. Afin de pallier les limites des membranes actuellement utilisées, des recherches récentes tentent de développer de nouvelles membranes dites « bio-actives ». Du fait de ses propriétés biologiques, la membrane amniotique humaine (MAH) pourrait être une alternative aux membranes conventionnellement utilisées pour la ROG. L’objectif principal de ce travail était de déterminer les meilleures conditions d’utilisation de la MAH pour la régénération de pertes de substances osseuses. Dans une première partie expérimentale, l’influence des faces de la MAH appliquées au contact du défaut ainsi que l’effet de la cryopréservation ont été étudiés. Dans une seconde partie expérimentale, une nouvelle méthode de décellularisation de la MAH, simple et reproductible a été développée. Dans une troisième partie expérimentale, la réparation osseuse de défauts de taille non-critiques et critiques a été évaluée en présence de la MAH préservée selon différentes méthodes. Les résultats ont montré que ni les cellules souches contenues dans la MAH, ni la face appliquée au contact du défaut n’avaient d’influence sur la régénération osseuse. La MAH décellularisée/lyophilisée semblait être la méthode de préservation la plus prometteuse en vue de son utilisation en régénération osseuse. / Guided bone regeneration (GBR) is commonly used to repair damaged bone. GBR is based on the application of a membrane which will act as a physical barrier to isolate the intended bone-healing space. The development of bioactive membranes has been suggested to overcome some limitations of the currently used membrane. Due to its biological properties, the human amniotic membrane (HAM) is a new biological membrane option for GBR. This study aimed at investigating the most suitable conditions to use HAM for GBR. First, the influence of both HAM sides and the impact of cryopreservation were studied. Then, a new decellularization process of HAM, that is simple and reproducible, has been developed. In a third part, bone regeneration of non-critical and critical sized defects depending on the preservation method of HAM was assessed in rodents. Results showed that neither stem cells found in HAM, nor the HAM layer used to cover the defect had an influence on its potential for bone regeneration. The most promising results were achieved with the decellularized/lyophilized HAM for the field of bone regeneration.

La greffe de Membrane Amniotique Humaine (MAH) permet la cicatrisation des ulcères pré-perforants de la cornée et de sauver un nombre significatif d'yeux victimes de brûlures chimiques. La MAH est un matériel biologique, son utilisation pour le traitement des maladies de la surface oculaire donne de bons résultats en raison de sa capacité à réduire l'inflammation et promouvoir une épithélialisation rapide. Pour son utilisation en clinique, la MAH doit bien évidemment être stérile, mais aussi facile à transporter du centre préleveur au centre greffeur, et stockable longtemps et facilement. Actuellement en routine à la banque de tissus de Rouen, la membrane amniotique est séparée de l’amnios puis dénudée de leur couche spongieuse. Par la suite cette membrane est conservée par cryopréservation (congélation à –80°C) ce qui complique potentiellement l’acheminement des membranes. Par conséquent, dans le cadre de cette étude avec la Banque Normande de Cornées du CHU de Rouen nous avons développé la lyophilisation des MAH pour faciliter son utilisation et sa distribution. L’étude du mapping de la MAH permettra également de déterminer si le taux de facteurs de croissance est homogène dans la MAH ou s’il dépend sa distance par rapport au cordon ombilical. L’étude de la biocompatibilité in vivo d’un deuxième matériau composé de collagène nous permet également d’envisager une alternative pour une implantation du stroma. Nos analyses protéiques (ELISA et Label-free) des MAH la lyophilisées ne montrent pas de différence significative en terme de quantité et de qualité protéique. L’approche protéomique est complétée par l’analyse de la capacité des cellules épithéliales de cornée humaines (CEC) à se multiplier sur la membrane amniotique lyophilisée in vitro. Nous n’avons pas observé de différence entre la croissance des cellules épithéliales sur la MAH lyophilisée ou congelée. L’analyse du total de protéines extraites montre également que la lyophilisation ne dégrade pas les MAH au niveau protéique.Au niveau structurel les résultats de la microscopie électronique ont montré que la structure du stroma de la MAH est impactée par la lyophilisation. La greffe des MAH a été réalisée sur les ulcères cornéens chez le lapin. Au cours de l’expérimentation les lapins n’ont pas montré de signe d’inflammation, les analyses histologiques ont mis en évidence l’épithélialisation de la surface oculaire. Ce projet est en collaboration avec l‘association ophtalmo sans frontière pour qu’à terme le développement de l’utilisation clinique des MAHL répondant notamment à des besoins humanitaires (Cameroun). Notre étude de la cartographie de la MAH a également montré qu’une variabilité en termes de quantité de protéine existe entre les différents donneurs. Dans cette étude nous avons également montré que la couche spongieuse est une source de facteurs de croissance importante dans le processus de cicatrisation des ulcères cornéens. / The Human Amniotic Membrane (HAM) graft allows the healing of corneal ulcers and rescues a significant number of eyes with chemical burn. HAM is a biological material, its use for the treatment of ocular surface diseases gives good results because of its ability to reduce inflammation and promote rapid epithelialization. For its clinical use, the HAM must of course be sterile, but also easy to transport from the sampling center to the transplant center, and easily storable and for a long time. Currently on routine in the tissue bank of Rouen, the amniotic membrane is separated from the amnion and denuded of its spongy layer. Subsequently this membrane is stored by cryopreservation (freezing at -80 ° C) which potentially complicates the delivery of membranes. Consequently, as part of this study with the Banque Normande de Cornées of Rouen University Hospital, we have developed freeze-drying of HAM to facilitate its use and distribution. The HAM mapping study will also determine whether the level of growth factors is homogeneous in the HAM or whether it depends on its distance from the umbilical cord. The study of the in vivo biocompatibility of a second material composed of collagen also allows us to consider an alternative for implantation at the level of the stroma. Our protein analyzes (ELISA and Label-free) of freeze-dried HAM do not show any significant difference in terms of quantity and protein quality. The proteomic approach is complemented by the analysis of the ability of human corneal epithelial cells (CECs) to multiply on the freeze-dried amniotic membrane in vitro. We did not observe any difference between the epithelial cells growths on freeze-dried or frozen HAM. The analysis of the extracted protein total also shows that freeze-drying does not degrade the HAM at the protein level. At the structural level the electron microscopy results showed that the structure of the MAH stroma is impacted by freeze-drying. The MAH transplant performed on corneal ulcers in rabbits was performed. During the experiment the rabbits did not show any sign of inflammation, the histological analyzes highlighted the epithelialization of the ocular surface.This project is in collaboration with OSF association for the development of the clinical use of MAHL responding in particular to humanitarian needs (Cameroon). Our study of HAM mapping also showed that variability in terms of amount of protein exists between different donors. We have also shown that the spongy layer is an important source of important growth factor in the healing process of corneal ulcers.

Part I: Endothelial cells form the posterior layer of the cornea and are important for maintaining its transparency. Dysfunctional endothelium can only be restored by transplantation. The global shortage of donor corneas requires the search for alternative treatments. The preparation of the graft by tissue engineering methods is complicated by low proliferative capacity of endothelium. To date, no endothelium-specific marker has been defined and the existence of endothelial stem cells has not been confirmed yet. We have prepared a protocol for culturing endothelial cells from research-grade tissue - corneoscleral rims obtained after transplantation or corneas excluded from the transplant process. We monitored localization of selected proteins, including stem cell markers, in native tissue and in primary cell cultures. We prepared up to 6.4 cm2 of endothelium from one cornea/rim, which had cellular features comparable to the native endothelium. This approach can increase the amount of endothelium for research or transplantation purposes. Using indirect immunohistochemistry, we showed that none of the previously proposed endothelial molecular markers is specific for these cells. We detected the expression of stem cell markers throughout the endothelial layer. In the porcine cornea model, we monitored...

Made available in DSpace on 2015-03-26T13:47:07Z (GMT). No. of bitstreams: 1 texto completo.pdf: 803317 bytes, checksum: fc5cc2e40df938c5be793a101a6e3195 (MD5) Previous issue date: 2007-02-15 / União de Ensino Superior de Viçosa - UNIVIÇOSA / The amniotic membrane has been widely used in the repair of corneal ulcers showing good results as it exhibits anti-adhesive effect and bacteriostatics properties, it protects the wound, reduces pain, participates in the epithelization and is not immunogenic. This membrane can be used on corneal ulcers as a graft or a patch depending on its position. A superficial keratectomy was made on all of the 28 animals included in this study. On the resulted corneal ulcer of the 14 animals of the treated group an amniotic membrane was used as patch sutured with its epithelial surface over the experimentally made ulcer. The control group did not receive the patch. The animals were submitted to clinical evaluations 24 hours after the proceedings, at a two-day interval during the first week and at a four-day interval from the second week until 180 days after surgeries. The histological and morphometric analysis were undertaken at 1, 2, 7, 15, 30, 60 e 180 days after surgery. The amniotic membrane s effect as a patch and its incorporation to the cornea were evaluated. The time needed for the corneal repair of the treated group was compared to the control and the time needed for the cornea s complete transparence was observed. Glycerin at 99% was evaluated as a preservation medium and the binocular magnifying glass was evaluated during surgeries. The corneal opacity was always present both in the treated and the control group during 180 days. The membrane retained the inflammatory cells on its surface and provided an improvement on the repair process at the beginning, but at some point it delayed this process and its conclusion. The membrane and the trauma caused by the suture needle leaded to discomfort, conjunctival congestion, ocular secretion and stimulated neovascularization and corneal fibrosis. There was no incorporation of the membrane to the cornea. The glycerin at 99% acted efficiently as a preservation medium when analyzing contamination, but its anti-angiogenesis characteristics were lost. The binocular magnifying glass was efficient during these works proceedings. / A membrana amniótica tem sido amplamente utilizada na reparação de úlceras de córnea, demonstrando resultados satisfatórios por possuir efeito antiadesivo, propriedades bacteriostáticas, promover a proteção da lesão, reduzir a dor, auxiliar na epitelização e não possuir imunogenicidade. Esta membrana pode ser utilizada em lesões da córnea como enxerto ou como bandagem dependendo do seu posicionamento. Neste estudo, foi realizada a ceratectomia superficial em 28 coelhos. No grupo tratado, composto por 14 animas, utilizou-se a membrana amniótica canina como bandagem, suturada com sua face epitelial aplicada sobre o leito da úlcera experimental. O grupo controle não recebeu tratamento. A avaliação clínica foi realizada a partir de 24 horas após a realização dos procedimentos, em intervalos de 2 dias na primeira semana e de 4 dias da segunda semana até os 180 dias de pósoperatório. A avaliação histológica e morfométrica foram realizadas aos 1, 2, 7, 15, 30, 60 e 180 dias após a cirurgia. Observaram-se os efeitos da membrana amniótica como bandagem e sua incorporação à córnea. Comparou-se o tempo de reparação da córnea entre os grupos e verificou-se o período para que a córnea apresentasse transparência completa. Avaliaram-se ainda a eficácia da glicerina a 99% como meio de preservação das membranas e da lupa binocular como instrumento de magnificação do campo operatório nos procedimentos cirúrgicos. A opacidade corneana esteve presente em todos os animais, tanto no grupo tratado como no grupo controle, durante os 180 dias. A membrana atuou contendo as células inflamatórias em sua superfície e promoveu um avanço no início do processo de reparação, porém a partir de determinado momento retardou a sua conclusão; e juntamente com o trauma causado pela agulha de sutura causou desconforto, congestão conjuntival, secreção ocular e estimulou a neovascularização e a fibrose na córnea. Não houve incorporação da membrana à córnea. A glicerina a 99% atuou satisfatoriamente como meio de preservação da membrana no que diz respeito à contaminação, mas suas características antiangiogênicas foram perdidas. A lupa binocular mostrou ser eficiente na realização dos procedimentos cirúrgicos envolvidos neste trabalho.

P.Trošan Ph.D. Thesis Abstract Limbal stem cell deficiency (LSCD) is a disease characterized by the deficiency of stem cells in the limbus, which are responsible for the homeostasis and renewal of the corneal epithelium. This disorder results in corneal neovascularization, chronical inflammation and opacification, which may lead to loss of vision. The most successful treatment is the transplantation of limbal tissue or cultured limbal epithelial cells (LECs) onto the damaged ocular surface. The human amniotic membrane (HAM) is used as the feeder of the LECs culture, as well as for the LSCD treatment. HAM is also widely used in clinical practice, particularly for the treatment of chronic wounds. This dissertation is particularly concerned on cell therapy for LSCD, on preparation of cells suitable for grafting onto the ocular surface, on the improvement of the LECs culture conditions, and on the preparation of appropriate carrier for the transfer of cells onto the damaged cornea. During my work I have used a wide spectrum of methods, e.g. cell cultures (LECs, mesenchymal stem, amniotic epithelial, conjunctival epithelial, goblet and 3T3 cells), immunohisto- and immunocytochemistry, microscopy, proliferation and colony forming assays, reverse transcription and quantitative real-time PCRs and statistical...

In dieser Arbeit wurden Methoden entwickelt und verglichen, um aus Corneoskleralringen langzeitorgankonservierter Hornhäute und intakten, kryokonservierten Amnionmembranen Limbusepithel-Amnion-Transplantate herzustellen. Als erfolgreichste Kultivierungsmethode stellte sich hierbei signifikant die Explantat-Technik mit nach unten gerichtetem Limbusepithel heraus. Hier konnte eine Auswachsrate von 42 % erzielt werden. Es wurde weiterhin gezeigt, dass das ausgewachsene, mehrschichtige Limbusepithel proliferationsfähige TACs (Transient Amplifying Cells) enthält. Weiterhin konnten mittels Regressionsanalyse signifikante Zusammenhänge zwischen Spenderalter, Post-mortem-Zeit, Organkultur-Dauer und der Auswachsrate beschrieben werden. Kurzgefasst wurde die Vermutung bestätigt, dass jede Verlängerung der unterschiedlichen Zeiten eine Verringerung der Auswachsrate zur Folge hat. Die hergestellten Limbusepithel-Amnion-Transplantate könnten für Patienten mit Limbusstammzellinsuffizienz unterschiedlicher Genese verwendet werden.

In dieser Arbeit wurden Methoden entwickelt und verglichen, um aus Corneoskleralringen langzeitorgankonservierter Hornhäute und intakten, kryokonservierten Amnionmembranen Limbusepithel-Amnion-Transplantate herzustellen. Als erfolgreichste Kultivierungsmethode stellte sich hierbei signifikant die Explantat-Technik mit nach unten gerichtetem Limbusepithel heraus. Hier konnte eine Auswachsrate von 42 % erzielt werden. Es wurde weiterhin gezeigt, dass das ausgewachsene, mehrschichtige Limbusepithel proliferationsfähige TACs (Transient Amplifying Cells) enthält. Weiterhin konnten mittels Regressionsanalyse signifikante Zusammenhänge zwischen Spenderalter, Post-mortem-Zeit, Organkultur-Dauer und der Auswachsrate beschrieben werden. Kurzgefasst wurde die Vermutung bestätigt, dass jede Verlängerung der unterschiedlichen Zeiten eine Verringerung der Auswachsrate zur Folge hat. Die hergestellten Limbusepithel-Amnion-Transplantate könnten für Patienten mit Limbusstammzellinsuffizienz unterschiedlicher Genese verwendet werden.