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Personne :
Deschambeault, Alexandre

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Structures organisationnelles

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Deschambeault

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Alexandre

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Centre LOEX de l'Université Laval, CHU de Québec, Hôpital du Saint-Sacrement

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ncf11851578

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Résultats de recherche

Voici les éléments 1 - 3 sur 3
  • PublicationRestreint
    Surface topography induces 3D self-orientation of cells and extracellular matrix resulting in improved tissue function
    (RSC Pub., 2009-01-15) Guillemette, Maxime.; Cui, Bo; Germain, Lucie; Roy, Emmanuel; Veres, Teodor; Auger, François A.; Giasson, Claude J.; Gauvin, Robert; Esch, Mandy B.; Carrier, Patrick; Deschambeault, Alexandre; Dumoulin, Michel; Toner, Mehmet
    The organization of cells and extracellular matrix (ECM) in native tissues plays a crucial role in their functionality. However, in tissue engineering, cells and ECM are randomly distributed within a scaffold. Thus, the production of engineered-tissue with complex 3D organization remains a challenge. In the present study, we used contact guidance to control the interactions between the material topography, the cells and the ECM for three different tissues, namely vascular media, corneal stroma and dermal tissue. Using a specific surface topography on an elastomeric material, we observed the orientation of a first cell layer along the patterns in the material. Orientation of the first cell layer translates into a physical cue that induces the second cell layer to follow a physiologically consistent orientation mimicking the structure of the native tissue. Furthermore, secreted ECM followed cell orientation in every layer, resulting in an oriented self-assembled tissue sheet. These self-assembled tissue sheets were then used to create 3 different structured engineered-tissue: cornea, vascular media and dermis. We showed that functionality of such structured engineered-tissue was increased when compared to the same non-structured tissue. Dermal tissues were used as a negative control in response to surface topography since native dermal fibroblasts are not preferentially oriented in vivo. Non-structured surfaces were also used to produce randomly oriented tissue sheets to evaluate the impact of tissue orientation on functional output. This novel approach for the production of more complex 3D tissues would be useful for clinical purposes and for in vitro physiological tissue model to better understand long standing questions in biology.
  • PublicationAccès libre
    Characterization of wound reepithelialization using a new human tissue–engineered corneal wound healing model
    (Association for Research in Vision and Ophthalmology, 2008-04-01) Giasson, Claude-J.; Guérin, Sylvain; Germain, Lucie; Giroux-Talbot, Mariève; Auger, François A.; Carrier, Patrick; Deschambeault, Alexandre
    Purpose. The reepithelialization of the corneal surface is an important process for restoring the imaging properties of this tissue. The purpose of the present study was to characterize and validate a new human in vitro three-dimensional corneal wound healing model by studying the expression of basement membrane components and integrin subunits that play important roles during epithelial cell migration and to verify whether the presence of exogenous factors could accelerate the reepithelialization. Methods. Tissue-engineered human cornea was wounded with a 6-mm biopsy punch, and the reepithelialization from the surrounding margins was studied. Biopsy samples of the reepithelialized surface were harvested 3 days after wounding and were processed for histologic, electron microscopic, and immunofluorescence analyses. The effects of fibrin and epithelial growth factor (EGF) on wound reepithelialization were also studied. Results. Results demonstrated that this in vitro model allowed the migration of human corneal epithelial cells on a natural extracellular matrix. During reepithelialization, epithelial cell migration followed a consistent wavelike pattern similar to that reported for human corneal wound healing in vivo. This model showed a histologic appearance similar to that of native tissue as well as expression and modulation of basement membrane components and the integrin subunits known to be main actors during the wound healing process. It also allowed quantification of the reepithelialization rate, which was significantly accelerated in the presence of fibrin or EGF. The results indicated that αvβ6 integrin expression was increased in the migrating epithelial cells compared with the surrounding corneal tissue. Conclusions. The similarity observed with the in vivo wound healing process supports the use of this tissue-engineered model for investigating the basic mechanisms involved in corneal reepithelialization. Moreover, this model may also be used as a tool to screen agents that affect reepithelialization or to evaluate the effect of growth factors before animal testing.
  • PublicationAccès libre
    Reconstruction of a human cornea by the self-assembly approach of tissue engineering using the three native cell types
    (Éditeur non identifié, 2010-10-29) Giasson, Claude-J.; Guérin, Sylvain; Germain, Lucie; Audet, Caroline; Auger, François A.; Uwamaliya, Jeanne d'Arc; Proulx, Stéphanie; Carrier, Patrick; Deschambeault, Alexandre
    Purpose: The purpose of this study was to produce and characterize human tissue-engineered corneas reconstructed using all three corneal cell types (epithelial, stromal, and endothelial cells) by the self-assembly approach. Methods: Fibroblasts cultured in medium containing serum and ascorbic acid secreted their own extracellular matrix and formed sheets that were superposed to reconstruct a stromal tissue. Endothelial and epithelial cells were seeded on each side of the reconstructed stroma. After culturing at the air-liquid interface, the engineered corneas were fixed for histology and transmission electron microscopy (TEM). Immunofluorescence labeling of epithelial keratins, basement membrane components, Na+/K+-ATPase α1, and collagen type I was also performed. Results: Epithelial and endothelial cells adhered to the reconstructed stroma. After 10 days at the air-liquid interface, the corneal epithelial cells stratified (4 to 5 cell layers) and differentiated into well defined basal and wing cells that also expressed Na+/K+-ATPase α1 protein, keratin 3/12, and basic keratins. Basal epithelial cells from the reconstructed epithelium formed many hemidesmosomes and secreted a well defined basement membrane rich in laminin V and collagen VII. Endothelial cells formed a monolayer of tightly-packed cells and also expressed the function related protein Na+/K+-ATPase α1. Conclusions: This study demonstrates the feasibility of producing a complete tissue-engineered human cornea, similar to native corneas, using untransformed fibroblasts, epithelial and endothelial cells, without the need for exogenous biomaterial.