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 :
Gauvin, Robert

En cours de chargement...
Photo de profil

Adresse électronique

Date de naissance

Projets de recherche

Structures organisationnelles

Fonction

Nom de famille

Gauvin

Prénom

Robert

Affiliation

Université Laval. Faculté de médecine

ISNI

ORCID

Identifiant Canadiana

ncf12139335

person.page.name

Résultats de recherche

Voici les éléments 1 - 10 sur 28
  • PublicationRestreint
    Considerations in the choice of a skin donor site for harvesting keratinocytes containing a high proportion of stem cells for culture in vitro
    (Butterworth-Heinemann, 2010-12-03) Germain, Lucie; Larouche, Danielle; Paquet, Claudie; Fugère, Claudia.; Genest, Hervé; Auger, François A.; Gauvin, Robert; Têtu, Félix-Andre; Bouchard, Maurice; Roy, Aphonse; Fradette, Julie; Lavoie, Amélie; Beauparlant, Annie.
    The treatment of severely burned patients has benefited from the grafting of skin substitutes obtained by expansion of epithelial cells in culture. The aim of this study was to evaluate whether the anatomic site chosen for harvesting skin had an impact on the quality of the derived cell cultures. Considering that hair follicles contain epithelial stem cells, we compared hairy skin sites featuring different densities and sizes of hair follicles for their capacity to generate high quality keratinocyte cultures. Three anatomic sites from adult subjects were compared: scalp, chest skin and p-auricular (comprising pre-auricular and post-auricular) skin. Keratin (K) 19 was used as a marker to evaluate the proportion of stem cells. Keratinocytes were isolated using the two-step thermolysin and trypsin cell extraction method, and cultured in vitro. The proportion of K19-positive cells harvested from p-auricular skin was about twice that of the scalp. This K19-positive cell content also remained higher during the first subcultures. In contrast to these in vitro results, the number of K19-positive cells estimated in situ on skin sections was about double in scalp as in p-auricular skin. Chest skin had the lowest number of K19-positive cells. These results indicate that in addition to the choice of an adult anatomic site featuring a high number of stem cells in situ, the quality of the cultures greatly depends on the ability to extract stem cells from the skin biopsy
  • PublicationAccès libre
    In vivo remodeling of fibroblast-derived vascular scaffolds implanted for 6 months in rats
    (Hindawi, 2016-11-24) Tondreau, Maxime; Laterreur, Véronique; Germain, Lucie; Vallières, Karine; Ruel, Jean; Tremblay, Catherine; Bourget, Jean-Michel; Auger, François A.; Gauvin, Robert; Lacroix, Dan.
    There is a clinical need for tissue-engineered small-diameter (<6 mm) vascular grafts since clinical applications are halted by the limited suitability of autologous or synthetic grafts. This study uses the self-assembly approach to produce a fibroblast-derived decellularized vascular scaffold (FDVS) that can be available off-the-shelf. Briefly, extracellular matrix scaffolds were produced using human dermal fibroblasts sheets rolled around a mandrel, maintained in culture to allow for the formation of cohesive and three-dimensional tubular constructs, and decellularized by immersion in deionized water. The FDVSs were implanted as an aortic interpositional graft in six Sprague-Dawley rats for 6 months. Five out of the six implants were still patent 6 months after the surgery. Histological analysis showed the infiltration of cells on both abluminal and luminal sides, and immunofluorescence analysis suggested the formation of neomedia comprised of smooth muscle cells and lined underneath with an endothelium. Furthermore, to verify the feasibility of producing tissue-engineered blood vessels of clinically relevant length and diameter, scaffolds with a 4.6 mm inner diameter and 17 cm in length were fabricated with success and stored for an extended period of time, while maintaining suitable properties following the storage period. This novel demonstration of the potential of the FDVS could accelerate the clinical availability of tissue-engineered blood vessels and warrants further preclinical studies.
  • PublicationRestreint
    Minimal contraction for tissue-engineered skin substitutes when matured at the air–liquid interface
    (John Wiley & Sons, 2013-06-03) Germain, Lucie; Larouche, Danielle; Auger, François A.; Marcoux, Hugo-Bastien; Gauvin, Robert; Guignard, Rina
    The structural stability of skin substitutes is critical to avoid aesthetic and functional problems after grafting, such as contractures and hypertrophic scars. The present study was designed to assess the production steps having an influence on the contractile behaviour of the tissue-engineered skin made by the self-assembly approach, where keratinocytes are cultured on tissue-engineered dermis comprised of fibroblasts and the endogenous extracellular matrix they organized. Thus, different aspects were investigated, such as the assembly method of the engineered dermis (various sizes and anchoring designs) and the impact of epithelial cell differentiation (culture submerged in the medium or at the air–liquid interface). To evaluate the structural stability at the end of the production, the substitutes were detached from their anchorages and deposited on a soft substrate, and contraction was monitored over 1 week. Collected data were analysed using a mathematical model to characterize contraction. We observed that the presence of a differentiated epidermis significantly reduced the amount of contraction experienced by the engineered tissues, independently of the assembly method used for their production. When the epidermis was terminally differentiated, the average contraction was only 24 4% and most of the contraction occurred within the first 12 h following deposition on the substrate. This is 2.2-fold less compared to when the epidermis was cultured under the submerged condition, or when tissue-engineered dermis was not overlaid with epithelial cells. This study highlights that the maturation at the air–liquid interface is a critical step in the reconstruction of a tissue engineered skin that possesses high structural stability
  • PublicationRestreint
    Restoration of the transepithelial potential within tissue-engineered human skin in vitro and during the wound healing process in vivo
    (Mary Ann Liebert, 2010-08-05) Plante, Michel; Germain, Lucie; Roberge, Charles; Auger, François A.; Gauvin, Robert; Dubé, Jean; Goulet, Daniel; Rochette-Drouin, Olivier; Bourdages, Michel; Lévesque, Philippe; Moulin, Véronique
    Normal human epidermis possesses a transepithelial potential (TEP) that varies in different parts of the body (10–60 mV). The role of TEP in normal epidermis is not yet identified; but after skin injury, TEP disruption induces an endogenous direct current electric field (100–200 mV/mm) directed toward the middle of the wound. This endogenous electric field could be implicated in the wound healing process by attracting cells, thus facilitating reepithelialization. However, little is known on the restoration of the TEP during human skin formation and wound healing. In this study, the variations in TEP and Na+/K+ ATPase pump expression during the formation of the epithelium were investigated in vitro using human tissue-engineered human skin (TES) reconstituted by tissue engineering and in vivo with a porcine wound healing model. Results showed that TEP undergoes ascending and decreasing phases during epithelium formation in TES as well as during wound repair within TES. Similar results were observed during in vivo reepithelialization of wounds. The ascending and decreasing TEP values were correlated with changes in the expression of Na+/K+ ATPase pump. The distribution of Na+/K+ ATPase pumps also varied according to epidermal differentiation. Taken together, these results suggest that the variations in the expression of Na+/K+ ATPase pump over time and across epidermis would be a determinant parameter of the TEP, dictating a cationic transport during the formation and restoration of the epidermis. Therefore, this study brings a new perspective to understand the formation and restoration of TEP during the cutaneous wound healing process. This might have important future medical applications regarding the treatment of chronic wound healing.
  • PublicationAccès libre
    Electric potential across epidermis and its role during wound healing can be studied by using an in vitro reconstructed human skin
    (S-N Publications, 2012-02-28) Plante, Michel; Germain, Lucie; Roberge, Charles; Auger, François A.; Gauvin, Robert; Dubé, Jean; Rochette-Drouin, Olivier; Goulet, Daniel; Lévesque, Philippe; Bourdages, Michel; Moulin, Véronique
    Background : After human epidermis wounding, transepithelial potential (TEP) present in nonlesional epidermis decreases and induces an endogenous direct current epithelial electric field (EEF) that could be implicated in the wound re-epithelialization. Some studies suggest that exogenous electric stimulation of wounds can stimulate healing, although the mechanisms remain to be determined. The Problem : Little is known concerning the exact action of the EEF during healing. The mechanism responsible for TEP and EEF is unknown due to the lack of an in vitro model to study this phenomenon. Basic Science Advances : We carried out studies by using a wound created in a human tissue-engineered skin and determined that TEP undergoes ascending and decreasing phases during the epithelium formation. The in vitro TEP measurements over time in the wound were corroborated with histological changes and with in vivo TEP variations during porcine skin wound healing. The expression of a crucial element implicated in Na+ transport, Na+/K+ ATPase pumps, was also evaluated at the same time points during the re-epithelialization process. The ascending and decreasing TEP values were correlated with changes in the expression of these pumps. The distribution of Na+/K+ ATPase pumps also varied according to epidermal differentiation. Further, inhibition of the pump activity induced a significant decrease of the TEP and of the re-epithelization rate. Clinical Care Relevance : A better comprehension of the role of EEF could have important future medical applications regarding the treatment of chronic wound healing. Conclusion : This study brings a new perspective to understand the formation and restoration of TEP during the cutaneous wound healing process.
  • PublicationRestreint
    Tissue reorganization in response to mechanical load increases functionality
    (2005-02-28) Bergeron, François; Langelier, Ève.; Grenier, Guillaume.; Germain, Lucie; Larouche, Danielle; Dupuis, Daniel; Rancourt, Denis; Auger, François A.; Gauvin, Robert; Baker, Kathleen; Rémy-Zolghadri, Murielle
    In the rapidly growing field of tissue engineering, the functional properties of tissue substitutes are recognized as being of the utmost importance. The present study was designed to evaluate the effects of static mechanical forces on the functionality of the produced tissue constructs. Living tissue sheets reconstructed by the self-assembly approach from human cells, without the addition of synthetic material or extracellular matrix (ECM), were subjected to mechanical load to induce cell and ECM alignment. In addition, the effects of alignment on the function of substitutes reconstructed from these living tissue sheets were evaluated. Our results show that tissue constructs made from living tissue sheets, in which fibroblasts and ECM were aligned, presented higher mechanical resistance. This was assessed by the modulus of elasticity and ultimate strength as compared with tissue constructs in which components were randomly oriented. Moreover, tissue-engineered vascular media made from a prealigned living tissue sheet, produced with smooth muscle cells, possessed greater contractile capacity compared with those produced from living tissue sheets that were not prealigned. These results show that the mechanical force generated by cells during tissue organization is an asset for tissue component alignment. Therefore, this work demonstrates a means to improve the functionality (mechanical and vasocontractile properties) of tissues reconstructed by tissue engineering by taking advantage of the biomechanical forces generated by cells under static strain.
  • PublicationRestreint
    A novel cylindrical biaxial computer-controlled bioreactor and biomechanical testing device for vascular tissue engineering
    (Mary Ann Liebert, 2009-04-22) Zaucha, Michael T.; Germain, Lucie; Raykin, Julia; Auger, François A.; Wan, William; Gauvin, Robert; Michaels, Thomas E.; Gleason, Rudolph L.
    It is becoming evident that tissue-engineered constructs adapt to altered mechanical loading, and that specific combinations of multidirectional loads appear to have a synergistic effect on the remodeling. However, most studies of mechanical stimulation of engineered vascular tissue engineering employ only uniaxial stimulation. Here we present a novel computer-controlled bioreactor and biomechanical testing device designed to precisely and simultaneously control mean and cyclic values of transmural pressure (at rates up to 1 Hz and ranges of 40 mmHg), luminal flow rate, and axial length (or load) applied to gel-derived, scaffold-derived, and self-assembly-derived tissue-engineered blood vessels during culture, while monitoring vessel geometry with a resolution of 6.6 μm. Intermittent monitoring of the extracellular matrix and cells is accomplished on live tissues using multi-photon confocal microscopy under unloaded and loaded conditions at multiple time-points in culture (on the same vessel) to quantify changes in cell and extracellular matrix content and organization. This same device is capable of performing intermittent cylindrical biaxial biomechanical testing at multiple time-points in culture (on the same vessel) to quantify changes in the mechanical behavior during culture. Here we demonstrate the capabilities of this new device on self-assembly-derived and collagen-gel-derived tissue-engineered blood vessels.
  • PublicationRestreint
    Biaxial biomechanical properties of self-assembly tissue-engineered blood vessels
    (Royal Society, 2010-06-16) Zaucha, Michael T.; Germain, Lucie; Auger, François A.; Gauvin, Robert; Gleason, Rudolph L.
    Along with insights into the potential for graft success, knowledge of biomechanical properties of small diameter tissue-engineered blood vessel (TEBV) will enable designers to tailor the vessels' mechanical response to closer resemble that of native tissue. Composed of two layers that closely mimic the native media and adventitia, a tissue-engineered vascular adventitia (TEVA) is wrapped around a tissue-engineered vascular media (TEVM) to produce a self-assembled tissue-engineered media/adventia (TEVMA). The current study was undertaken to characterize the biaxial biomechanical properties of TEVM, TEVA and TEVMA under physiological pressures as well as characterize the stress-free reference configuration. It was shown that the TEVA had the greatest compliance over the physiological loading range while the TEVM had the lowest compliance. As expected, compliance of the SA-TEBV fell in between with an average compliance of 2.73 MPa−1. Data were used to identify material parameters for a microstructurally motivated constitutive model. Identified material parameters for the TEVA and TEVM provided a good fit to experimental data with an average coefficient of determination of 0.918 and 0.868, respectively. These material parameters were used to develop a two-layer predictive model for the response of a TEVMA which fit well with experimental data.
  • PublicationAccès libre
    Improved methods to produce tissue-engineered skin substitutes suitable for the permanent closure of full-thickness skin injuries
    (Mary Ann Liebert, 2016-11-01) Germain, Lucie; Larouche, Danielle; Auger, François A.; Martel, Israël; Cantin-Warren, Laurence; Ayoub, Akram; Gauvin, Robert; Guignard, Rina; Desgagné, Maxime; Moulin, Véronique; Lavoie, Amélie
    There is a clinical need for skin substitutes to replace full-thickness skin loss. Our group has developed a bilayered skin substitute produced from the patient’s own fibroblasts and keratinocytes referred to as Self-Assembled Skin Substitute (SASS). After cell isolation and expansion, the current time required to produce SASS is 45 days. We aimed to optimize the manufacturing process to standardize the production of SASS and to reduce production time. The new approach consisted in seeding keratinocytes on a fibroblast-derived tissue sheet before its detachment from the culture plate. Four days following keratinocyte seeding, the resulting tissue was stacked on two fibroblast-derived tissue sheets and cultured at the air–liquid interface for 10 days. The resulting total production time was 31 days. An alternative method adapted to more contractile fibroblasts was also developed. It consisted in adding a peripheral frame before seeding fibroblasts in the culture plate. SASSs produced by both new methods shared similar histology, contractile behavior in vitro and in vivo evolution after grafting onto mice when compared with SASSs produced by the 45-day standard method. In conclusion, the new approach for the production of high-quality human skin substitutes should allow an earlier autologous grafting for the treatment of severely burned patients.
  • PublicationRestreint
    Mechanical properties of tissue-engineered vascular constructs produced using arterial or venous cells
    (Mary Ann Liebert, Inc. Publishers, 2011-04-02) Guillemette, Maxime.; Germain, Lucie; Galbraith, Todd; Larouche, Danielle; Aubé, David; Marcoux, Hugo; Hayward, Cindy Jean; Bourget, Jean-Michel; Auger, François A.; Gauvin, Robert
    There is a clinical need for better blood vessel substitutes, as current surgical procedures are limited by the availability of suitable autologous vessels and suboptimal behavior of synthetic grafts in small caliber arterial graft (<5 mm) applications. The aim of the present study was to compare the mechanical properties of arterial and venous tissue-engineered vascular constructs produced by the self-assembly approach using cells extracted from either the artery or vein harvested from the same human umbilical cord. The production of a vascular construct comprised of a media and an adventitia (TEVMA) was achieved by rolling a continuous tissue sheet containing both smooth muscle cells and adventitial fibroblasts grown contiguously in the same tissue culture plate. Histology and immunofluorescence staining were used to evaluate the structure and composition of the extracellular matrix of the vascular constructs. The mechanical strength was assessed by uniaxial tensile testing, whereas viscoelastic behavior was evaluated by stepwise stress-relaxation and by cyclic loading hysteresis analysis. Tensile testing showed that the use of arterial cells resulted in stronger and stiffer constructs when compared with those produced using venous cells. Moreover, cyclic loading demonstrated that constructs produced using arterial cells were able to bear higher loads for the same amount of strain when compared with venous constructs. These results indicate that cells isolated from umbilical cord can be used to produce vascular constructs. Arterial constructs possessed superior mechanical properties when compared with venous constructs produced using cells isolated from the same human donor. This study highlights the fact that smooth muscle cells and fibroblasts originating from different cell sources can potentially lead to distinct tissue properties when used in tissue engineering applications.