Pour savoir comment effectuer et gérer un dépôt de document, consultez le « Guide abrégé – Dépôt de documents » sur le site Web de la Bibliothèque. Pour toute question, écrivez à corpus@ulaval.ca.
 

Personne :
Xu, Wen

En cours de chargement...
Photo de profil

Adresse électronique

Date de naissance

Projets de recherche

Structures organisationnelles

Fonction

Nom de famille

Xu

Prénom

Wen

Affiliation

Département de chirurgie, Faculté de médecine, Université Laval

ISNI

ORCID

Identifiant Canadiana

ncf11908143

person.page.name

Résultats de recherche

Voici les éléments 1 - 9 sur 9
  • PublicationAccès libre
    Grafting on nude mice of living skinquivalents produced using human collagens
    (Williams & Wilkins Co, 1996-08-15) Germain, Lucie; Xu, Wen; Auger, François A.; López Valle, Carlos Antonio; Guignard, Rina; Rouabhia, Mahmoud; Goulet, Francine
    Autologous epidermal transplantation for human burn management is an example of a significant breakthrough in tissue engineering. However, the main drawback with this treatment remains the fragility of these grafts during and after surgery. A new human bilayered skin equivalent (hSE) was produced in our laboratory to overcome this problem. The aim of the present work was to study skin regeneration after hSE grafting onto nude mice. A comparative study was carried out over a period of 90 days, between anchored bovine skin equivalent, hSE and hSE+, the latter containing additional matrix components included at concentrations similar to those in human skin in vivo. The addition of a dermal layer to the epidermal sheet led to successful graft take, enhanced healing, and provided mechanical resistance to the grafts after transplantation. In situ analysis of the grafts showed good ultrastructural organization, including the deposition of a continuous basement membrane 1 week after surgery.
  • PublicationRestreint
    Reconstructed human skin produced in vitro and grafted on athymic mice
    (Ovid, 2002-06-15) Li, Hui; Germain, Lucie; Xu, Wen; Larouche, Danielle; Juhász, Julianna; Auger, François A.; Pouliot, Roxane
    Background. The best alternative to a split-thickness graft for the wound coverage of patients with extensive burns should be in vitro reconstructed autologous skin made of both dermis and epidermis and devoid of exogenous extracellular matrix proteins and synthetic material. We have designed such a reconstructed human skin (rHS) and present here its first in vivo grafting on athymic mice. Methods. The rHS was made by culturing newborn or adult keratinocytes on superimposed fibrous sheets obtained after culturing human fibroblasts with ascorbic acid. Ten days after keratinocyte seeding, reconstructed skins were either cultured at the air-liquid interface or grafted on athymic mice. We present the macroscopic, histologic, and phenotypic properties of such tissues in vitro and in vivo after grafting on nude mice. Results. After maturation in vitro, the reconstructed skin exhibited a well-developed human epidermis that expressed differentiated markers and basement membrane proteins. Four days after grafting, a complete take of all grafts was obtained. Histological analysis revealed that the newly generated epidermis of newborn rHS was thicker than that of adult rHS after 4 days but similar 21 days after grafting. The basement membrane components (bullous pemphigoid antigens, laminin, and type IV and VII collagens) were detected at the dermo-epidermal junction, showing a continuous line 4 days after grafting. Ultrastructural studies revealed that the basement membrane was continuous and well organized 21 days after transplantation. The macroscopic aspect of the reconstructed skin revealed a resistant, supple, and elastic tissue. Elastin staining and elastic fibers were detected as a complex network in the rHS that contributes to the good elasticity of this new reconstructed tissue. Conclusions. This new rHS model gives supple and easy to handle skins while demonstrating an adequate wound healing on mice. These results are promising for the development of this skin substitute for permanent coverage of burn wounds.
  • PublicationRestreint
    Permanent grafting of living skin substitutes : surgical parameters to control for successful results
    (Ovid, 1996-01-01) Germain, Lucie; Xu, Wen; Auger, François A.; Goulet, Francine
    Autologous mesh grafting, widely used in the treatment of severe burns, remains the most conventional approach for permanent skin replacement. However, during the last decade several types of skin substitutes were reported as suitable alternatives for full-thickness burn wound coverage. The clinical use of such dressings requires new surgical skills to maintain the integrity of the grafts and favor their permanent implantation in vivo. This article reports observations made on nude mice grafted with cultured human skin equivalents. Some parameters such as the quality of adhesion between the implant and the graft bed, the size, the stability and the thickness of the graft, the humidity of the chamber, and the protocol of antibiotic administration were identified as crucial for the success of the surgery. The grafting procedures are described in this paper. These results should be taken into consideration in all transplantations of skin grafts m vivo.
  • PublicationRestreint
    Use of in vitro reconstructed skin to cover skin flap donor site
    (Academic Press, 2002-04-12) Li, Hui; Germain, Lucie; Xu, Wen; Damour, Odile; Auger, François A.; Berthod, François
    Background: The skin flap technique is widely used in reconstructive surgery for the coverage of deep burns of the face, neck, and joints. Facial deformities and joint contractures are avoided by transplanting vascularized full-thickness skin on wounds. The major drawback of this technique is the injury inflicted upon the donor site, which corresponds to a third degree burn. The usual technique to cover the flap donor site is the transplantation of split-thickness autografts. In the case of patients with deep and extensive burns, the harvesting of good quality autografts is often difficult because of multiple scars. In order to avoid additional trauma to the patient by split-thickness skin harvesting, we have experimented the use of a new model ofin vitroreconstructed skin graft for flap donor site coverage in a mouse model. Materials and methods: The reconstructed skin was grafted on the back of nude mice at the skin flap donor site, while flap was used to cover a wound generated on joint of the posterior leg. Results: A 100% graft take was achieved (16 mice were used) and a limited contraction of the reconstructed skin was observed 30 days posttransplantation (78% of the initial surface area of the graft remained). Histological analysis of the graft demonstrated healing of a well differentiated epidermis laying on a dense dermis. Conclusions: Since this technique would prevent additional trauma to the patient while achieving a good healing of the wound, it may be a useful approach in the coverage of skin flap donor site in humans.
  • PublicationRestreint
    Skin stem cell identification and culture : a potential tool for rapid epidermal sheet production and grafting
    (Landes Bioscience, 2018-01-29T18:34:34Z) Michel, Martine; Li, Hui; Germain, Lucie; Xu, Wen; Godbout, Marie-Josée; Fradette, Julie; Rouabhia, Mahmoud
    Stem cells are fascinating. They are a production factory and give rise to the differentiated tissues. During embryonic development, stem cells multiply and differentiate to generate the cellular diversity necessary for the formation of all tissues. The pluripotentiality of embryonic stem cells is very large. Stem cells in the embryo are probably different from those in adults in the sense that some embryonic stem cells are present only transiently and their pluripotentiality is greater than that of adult stem cells which are limited to one compartment, e.g., blood, cutaneous or intestinal epithelial cells. In this chapter, we will concentrate on skin stem cells of postnatal mammals. During the adult life, stem cells are responsible for tissue homeostasis; they proliferate to maintain the number of differentiated cells at a constant level and replace dead cells or cells lost through injury.
  • PublicationRestreint
    Collagen fibril network and elastic system remodeling in a reconstructed skin transplanted on nude mice
    (Elsevier Science, 2001-11-01) Li, Hui; Germain, Lucie; Xu, Wen; Auger, François A.; Damour, Odile; Berthod, François
    Wound healing of deep and extensive burns can induce hypertrophic scar formation, which is a detrimental outcome for skin functionality. These scars are characterized by an impaired collagen fibril organization with fibril bundles oriented parallel to each other, in contrast with a basket weave pattern arrangement in normal skin. We prepared a reconstructed skin made of a collagen sponge seeded with human fibroblasts and keratinocytes and grown in vitro for 20 days. We transplanted it on the back of nude mice to assess whether this reconstructed skin could prevent scar formation. After transplantation, murine blood vessels had revascularized one-third of the sponge thickness on the fifth day and were observed underneath the epidermis at day 15. The reconstructed skin extracellular matrix was mostly made of human collagen I, organized in loosely packed fibrils 5 days after transplantation, with a mean diameter of 45 nm. After 40–90 days, fibril bundles were arranged in a basket weave pattern while their mean diameter increased to 56 nm, therefore exactly matching mouse skin papillary dermis organization. Interestingly, we showed that an elastic system remodeling was started off in this model. Indeed, human elastin deposits were organized in thin fibrils oriented perpendicular to epidermis at day 90 whereas elastic system usually took years to be re-established in human scars. Our reconstructed skin model promoted in only 90 days the remodeling of an extracellular matrix nearly similar to normal dermis (i.e. collagen fibril diameter and arrangement, and the partial reconstruction of the elastic system).
  • PublicationRestreint
    Characterization of a new tissue-engineered human skin equivalent with hair
    (springerLink, 1999-06-01) Michel, Martine; Germain, Lucie; Xu, Wen; L'Heureux, Nicolas; Auger, François A.; Pouliot, Roxane
    We designed a new tissue-engineered skin equivalent in which complete pilosebaceous units were integrated. This model was produced exclusively from human fibroblasts and keratinocytes and did not contain any synthetic material. Fibroblasts were cultured for 35 d with ascorbic acid and formed a thick fibrous sheet in the culture dish. The dermal equivalent was composed of stacked fibroblast sheets and exhibited some ultrastructural organization found in normal connective tissues. Keratinocytes seeded on this tissue formed a stratified and cornified epidermis and expressed typical markers of differentiation (keratin 10, filaggrin, and transglutaminase). After 4 wk of culture, a continuous and ultrastructurally organized basement membrane was observed and associated with the expression of laminin and collagen IV and VII. Complete pilosebaceous units were obtained by thermolysin digestion and inserted in this skin equivalent in order to assess the role of the transfollicular route in percutaneous absorption. The presence of hair follicles abolished the lag-time observed during hydrocortisone diffusion and increased significantly its rate of penetration in comparison to the control (skin equivalent with sham hair insertion). Therefore, this new hairy human skin equivalent model allowed an experimental design in which the only variable was the presence of pilosebaceous units and provided new data confirming the importance of hair follicles in percutaneous absorption.
  • PublicationRestreint
    Cultured epidermal sheet grafting with Hemaseel HMN fibrin sealant on nude mice
    (Elsevier, 1999-12-08) Li, Hui; Germain, Lucie; Brodniewicz, Teresa; Xu, Wen; Auger, François A.
    Grafting of cultured epidermal sheets is a promising technique for skin restoration in extensive burns, but the technique has some limitations, resulting in variable graft takes. These experiments were designed to evaluate the innocuity of HemaseelTM HMN fibrin sealant in the grafting process and in vivo evolution of cultured epidermis. A total of 30 mice were grafted, 15 were controls, 15 received tissue sealant application before the deposition of the cultured human epidermal sheets. Seven days after transplantation, compared to controls, the percentage of graft take over the total surface area grafted was greater in animals that had received the tissue sealant application. No difference was found 14 and 21 days postgrafting. In contrast, the percentage of graft take over the bony area (spinal) was significantly increased in animals grafted with previous application of sealant compared to controls at 7, 14 and 21 days postgrafting. Immunohistological and ultrastructural analysis showed that the evolution of the cultured human epidermis after transplantation was similar in both groups. The basement membrane was well structured 21 days after transplantation. The sealant was present at 4 days but not at 21 days postgrafting. Therefore, we conclude that the application of fibrin sealant before cultured epidermal sheet deposition on nude mouse graft bed is innocuous and enhances their mechanical stability. Since in this nude mouse system HemaseelTM HMN fibrin sealant increased the percentage of graft take over areas difficult to engraft, we think that it may be advantageous in cultured epidermal sheet grafting on burn patients.
  • PublicationAccès libre
    Morphologic and functional properties of bronchial cells isolated from normal and asthmatic subjects
    (American Thoracic Society, 1996-09-01) Boutet, Michel; Tremblay, Nathalie; Germain, Lucie; Chakir, Jamila; Xu, Wen; Boulet, Louis-Philippe; Auger, François A.; Dubé, Jean; Laviolette, Michel; Goulet, Francine
    Recent advances in biomedical sciences have led to the development of various methods for the evaluation of the physiopathology of respiratory diseases. This study reports morphologic and functional features of cells isolated by a new method from bronchial biopsies of normal and asthmatic subjects. Both epithelial and fibroblastic cells were isolated from the same biopsies using collagenase. The cells were cultured for several passages and stored frozen. Two selective culture media were used in order to obtain pure epithelial and fibroblastic cell populations. Immunofluorescence analysis of intermediate filaments, keratins, and vimentin confirmed the type of the isolated cells. The proportions of alpha-actin-expressing cells varied among the fibroblastic cell populations isolated from normal and asthmatic subjects. Interestingly, the population containing high numbers of alpha-actin-expressing cells and presenting the fastest collagen contraction kinetic was isolated from bronchial biopsies of an asthmatic subject. Moreover, the fibroblastic cells that showed the best contractile properties 24 h after their seeding in floating collagen gels were isolated from bronchial biopsies of asthmatic patients having PC20 values below 1 mg/ml. On the basis of these data, we propose a new approach to isolate, culture and characterize human bronchial cells in vitro.