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Resource Types :
chapitre d'ouvrage


chapitre d'ouvrage


A defined chapter or section of a book, usually with a separate title or number. [Source: http://purl.org/spar/fabio/BookChapter]

Terme retenu

capítulo de libro
Teil eines Buches
book part
chapitre d'ouvrage
capitolo di libro

Terme alternatif

book chapter
chapter in book
capitulo de libro
parte de libro
chapitre de livre
partie d'ouvrage

Terme spécifique


Terme générique

Terme relié

Broad Match: http://purl.org/eprint/type/Book
Exact Match: http://purl.org/spar/fabio/BookChapter
Exact Match: http://purl.org/eprint/type/BookItem

Résultats de recherche

Voici les éléments 1 - 10 sur 14
  • PublicationAccès libre
    What is new in mechanical properties of tissue-engineered organs
    (Springer, 1999-01-01) Germain, Lucie; Auger, François A.; Berthod, François; Goulet, Francine
    Tissue engineering is a promising new field based on expertise in cell biology, medicine and mechanical engineering. It raises exciting hopes of producing autologous tissue substitutes to replace altered organs. This challenge involves highly specialized technology in order to provide the proper shape to the tissue and promote the maintenance of its native physiological properties. Primary cell populations may lose some of their functional and morphological properties in vitro in the absence of a proper environment. In order to maintain cell integrity, a three-dimensional matrix that mimics the in vivo environment as closely as possible was developed, according to the type of tissue produced [1, 5, 18, 26, 27, 29, 34, 35].
  • PublicationRestreint
    A truly new approach for tissue engineering : the LOEX self-assembly technique
    (SpringerLink, 2002-01-01) Grenier, Guillaume.; Germain, Lucie; Auger, François A.; Rémy-Zolghadri, Murielle
    Tissue engineering has created several original and new avenues in the biomedical sciences. There is ongoing progress, but the tissue-engineering field is currently at a crossroads in its evolution; the validity of this technique is weIl established. Thus, new clinical applications must appear rapidly, within a few years, so that it will have a true impact on patient care. The self-assembly approach of the Laboratoire d'Organogénèse Expérimentale (LOEX) should be at the forefront.
  • PublicationRestreint
    Tissue Engineering of Cornea
    (Marcel Dekker, 2004-06-23) Giasson, Claude-J.; Guérin, Sylvain; Salesse, Christian; Germain, Lucie; Auger, François A.; Carrier, Patrick
    The cornea is the transparent barrier between the eye and the environment. Tissue-engineered corneas are currently developed to replace wounded or diseased corneas. Various experimental applications are also foreseen for these tissues reconstructed in vitro by tissue engineering. This article covers the first human corneas reconstructed by tissue engineering from normal human cells and the different models used for the production of human and animal corneas in vitro. Corneal injury and the activation of the complex wound«hea]ing mechanisms are also addressed. Finally, we will attempt to provide the reader with a brief look toward the future of corneal tissue engineering, including the challenges that lie ahead as well as the potential experimental and clinical applications of this field.
  • PublicationAccès libre
    Alignment of cells and extracellular matrix within tissue-engineered substitutes
    (Intech, 2013-01-01) Guillemette, Maxime.; Germain, Lucie; Bourget, Jean-Michel; Veres, Teodor; Auger, François A.
    Most of the cells in our body are in direct contact with extracellular matrix (ECM) components which constitute a complex network of nano-scale proteins and glycosaminoglycans. Those cells constantly remodel the ECM by different processes. They build it by secreting different proteins such as collagen, proteoglycans, laminins or degrade it by producing factors such as matrix metalloproteinase (MMP). Cells interact with the ECM via specific receptors, the integrins [1]. They also organize this matrix, guided by different stimuli, to generate patterns, essential for tissue and organ functions. Reciprocally, cells are guided by the ECM, they modify their morphology and phenotype depending on the protein types and organization via bidirectional integrin signaling [2-4]. In the growing field of tissue engineering [5], control of these aspects are of the utmost importance to create constructs that closely mimic native tissues. To do so, we must take into account the composition of the scaffold (synthetic, natural, biodegradable or not), its organization and the dimension of the structure. The particular alignment patterns of ECM and cells observed in tissues and organs such as the corneal stroma, vascular smooth muscle cells (SMCs), tendons, bones and skeletal muscles are crucial for organ function. SMCs express contraction proteins such as alpha-smoothmuscle (SM)-actin, desmin and myosin [6] that are essential for cell contraction [6]. To result in vessel contraction, the cells and ECM need to be organized in such a way that most cells are elongated in the same axis. For tubular vascular constructs, it is suitable that SMCs align in the circumferential direction, as they do in vivo [7, 8]. Another striking example of alignment is skeletal muscle cells that form long polynuclear cells, all elongated in the same axis. Each cell generates a weak and short contraction pulse but collectively, it results in a strong, long and sustained contraction of the muscle and, in term, a displacement of the member. In the corneal stroma, the particular arrangement of the corneal fibroblasts (keratocytes) and ECM is essential to keep the transparency of this tissue [9-13]. Tendons also present a peculiar matrix alignment relative to the muscle axis. It gives a substantial resistance and exceptional mechanical properties to the tissue in that axis [14, 15]. Intervertebral discs [16], cartilage [17], dental enamel [18], and basement membrane of epithelium are other examples of tissues/organs that present peculiar cell and matrix organization. By reproducing and controlling those alignment patterns within tissue-engineered substitutes, a more physiological representation of human tissues could be achieved. Taking into account the importance of cell microenvironment on the functionality of tissue engineered organ substitutes, one can assume the importance of being able to customise the 3D structure of the biomaterial or scaffold supporting cell growth. To do so, some methods have been developed and most of them rely on topographic or contact guidance. This is the phenomenon by which cells elongate and migrate in the same axis as the ECM. Topographic guidance was so termed by Curtis and Clark [19] to include cell shape, orientation and movement in the concept of contact guidance described by Harrison [20] and implemented by Weiss [21, 22]. Therefore, if one can achieve ECM alignment, cells will follow the same pattern. Inversely, if cells are aligned on a patterned culture plate, the end result would be aligned ECM deposition [23]. The specific property of tissues or materials that present a variation in their mechanical and structural properties in different axis is called anisotropy. This property can be evaluated either by birefringence measurements [24, 25], mechanical testing in different axis [26], immunological staining of collagen or actin filaments [23] or direct visualisation of collagen fibrils using their self-fluorescence around 488 nm [27, 28]. Several techniques have been recently developed to mimic the specific alignment of cells within tissues to produce more physiologically relevant constructs. In this chapter, we will describe five different techniques, collagen gel compaction, electromagnetic field, electro‐spinning of nanofibers, mechanical stimulation and microstructured culture plates.
  • PublicationRestreint
    Défis et perspectives de la médecine régénératrice cardiovasculaire
    (John Libbey Eurotext, 2008-01-01) Germain, Lucie; D’Orléans-Juste, Pedro; Labbé, Raymond; Auger, François A.
    Le présent chapitre sera consacré aux diverses méthodes de génie tissulaire ayant trait à la reconstruction des vaisseaux sanguins (in vitro) avec une visée clinique (in vivo). Toutefois, nous dédierons quelques lignes à l’utilisation de ces substituts vasculaires comme modèle in vitre pour des études parfois très pointues et complexes, dans les applications suivantes : physiologie, pathophysiologie, pharmacologie et toxicologie. Ainsi, un tour d’horizon non exhaustif des travaux de la reconstruction vasculaire au plan mondial s’accompagnera de notre expérience unique au Laboratoire d’Organogenèse EXpérimentale (LOEX). En effet, notre groupe est l’un des rares, sinon le seul, groupes de recherche à effectuer en parallèle des travaux en génie tissulaire tant sur les microvaisseaux (capillaires) que les artères de petit calibre (s 5 mm) [5, 6]. Ces deux aspects vasculaires du génie tissulaire répondent à deux impératifs cliniques. En premier lieu, les micro-vaisseaux permettent d’entrevoir une vascularisation préimplantatoire des organes reconstruits. Ainsi, les espoirs de survie de divers substituts seraient grandement améliorés puisqu'il s’agit là d’une des principales pierres d’achoppement de ce domaine. En second lieu, la création de vaisseaux cultivés de petits calibres répond à un besoin clinique, tels des pontages cardiaques et infrapoplités où les prothèses synthétiques sont inutilisables en raison d’une fréquence plus élevée de thrombose. Ainsi, le cahier de charge de ces substituts vasculaires (SV) obtenus par génie tissulaire est très exigeant comme démontre le Tableau I. Enfin, notons, dans un registre entièrement différent, que notre programme de recherche sur la reconstruction des valves cardiaques se poursuit actuellement [7].
  • PublicationRestreint
    A full spectrum of functional tissue-engineered blood vessels : from macroscopic to microscopic
    (Springer, 2003-01-01) Grenier, Guillaume.; Germain, Lucie; Auger, François A.; Rémy-Zolghadri, Murielle
    Tissue engineering has created several original and new avenues of investigation in biology (Auger et al., 2000). This new domain of research in biotechnology was introduced in the l980$ as a life-saving procedure for burn patients. The successful engrai‘tment of autologous living epidermis was the first proof of concept of this powerful approach. From the efforts in this field, two schools of thought emerged. A first one is the seeding of cells into various gels or scatTolds in which the cells secrete and/or reorganize the surrounding extracellular matrix (ECM), and a second one, the coaxing of cells onto the secretion of an abundant autologous ECM, thus creating their own environment in the absence of any exogenous material. This latter methodology, which we called the “self assembly approach,” takes advantage of the ability of cells to recreate in vitro tissue-like structures when appropriately cultured (Auger et al., 2000). The conditions entail particular media composition and adapted mechanical straining ol‘ these three-dimensional structures. Our own experience with the culture of autologous epidermal sheets gave us some insight in the property of cells to recreate such in rim: tissue-like structures. This expertise led us to develoP tissue-engineered structures on the basis ol‘ the following two concepts: the living substitutes that we created have no artificial biomaterial, and the ECM is either a biological one repopulated by the ceiis or an ECM neosynthesized by the cells themselves. Such living substitutes have distinct advantages because of their cellular composition that confer to them superior physiologicai characteristics when implanted into the human body, that is, their ability to renew themselves over time and their healing property if they are damaged. Moreover, the presence of autologous cells in the living reconstructed tissue should facilitate its interactions with the surrounding host environment. Here, we describe our own experience in the reconstruction of a full spectrum of blood vessels by tissue engineering: macroscopic and microscopic. We applied the self-assembly approach with some impressive results to the reconstruction of a small-diameter blood vessel and the use of a cell-seeded scaffold leading to the formation of capillary-like structures in a full-thickness skin. The following highlights the major points for the generation of these organs.
  • PublicationAccès libre
    Tissue Engineering
    (Marcel Dekker, 2004-01-01) Germain, Lucie; Auger, François A.
    There is little doubt that tissue engineering is a revolutionary addition to the therapeutic armamentarium of medicine. The dilemma of adequately repairing either failing or traumatized organs has been looming larger as patients either become older or are in dire need of grafts. Compounding some of the intrinsic problems of transplantation is the chronic shortage of tissues and organs. Tissue engineering allows the hope of a regular creation of spare parts for the human body. This is a most significant approach to reconstruct, replace, or repair organs in a way that could not be foreseen 25 years ago. Reconstructive medicine is, in a way, not a very recent concept. If one stays away from punctilious definitions, one of its forms, reconstructive surgery, has been practiced for quite some time, with a surge of development after the Second World War. In 1970s, the development of microsurgery allowed distant tissue transfer and reimplantation.[1-5] Since then, the introduction of various biomaterials has allowed vast and diversified types of reconstruction of the human body. Vascular grafts and prosthetic articulation are two prominent examples. However, tissue engineering does open a radically new chapter in reconstructive medicine, for it is now deemed possible to reconstruct in the laboratory human living tissues and organs for either in-vivo, ex-vivo, and even invitro applications. This new domain of biotechnology is remarkably multidisciplinary, bringing together cell and molecular biologists, biochemists, engineers, pharmacologists, physicians, and others. When the aim of tissue engineers is to obtain grafts for in-vivo applications, then the biological and mechanical functions are of utmost importance. In some subdivisions of the field, one can essentially choose between a biological function, as in cell therapy, and a principally mechanical function, as in the use of tissue templates (Fig. 1). Tissue-engineered substitutes are three-dimensional reconstructions that can be implanted into the human body, leading to rapid host integration and acceptance. These substitutes must have at least minimal biological and mechanical functions for such a reparative role.
  • PublicationRestreint
    Principles of living organ reconstruction by tissue engineering
    (Marcel Dekker, 2004-01-01) Germain, Lucie; Auger, François A.; Berthod, François; Goulet, Francine; Moulin, Véronique
    Tissue engineering is a novel sector arising from the biomaterial field, which is developing rapidly as a result of the dramatic cIinicalneed for organ replacement,since there is unfortunately an ever-growing lack of organs for transplantation. Various approaches are presently being developed in different laboratories and companies based on the utilization of biomaterials, extracellular matrix components, and cellsto produce substitutesto aJlowthe replacement of wounded or diseased tissues. Theorgan reconstructionby tissue engineering presented in this chapter are of living tissues. This concept entails that the various cells incorporated in our constructs or tissues are not only readily dividing, but also metabolically active. Thus, mesenchymal cells (fibroblasts, smooth muscle cells) incorporated into the stromal component of these substitutes are also significantly involved in the reorganization of the extracellular matrix. Furthermore, the interactions between the mesenchymal cells and the epithelial cells improve the very nature, structure, and function of the resulting organ. Lastly, the presence of living cells, within the in vitro engineered tissues, adds the benefit of tissue remodeling and healing after transplantation in vivo. The source of cells that can be used for tissue reconstruction is dictated by the foreseen application. Autologous cells will be necessary for the production of living tissue substitutes when striving for permanent replacement of organs in order to prevent any histocompatibility mismatch and the ensuing predictable rejection (e.g., skin grafting for full-thickness burns). However, the rejection process has been shown to vary with the type of cells involved, and it may be possible to graft allogeneic engineered tissue under some appropriate conditions. But in such cases as keratinocytes, dentritic cells and endothelial cells that are privileged targets for rejection, autologous ceIls are necessary to permanently replace tissues encompassing these cells. ln sharp contrast, when the living tissue substitute is destined to improve wound healing, such as in the case of uIcers,allogeneic cells are sufficientsince they act as a temporary coverage, enhancing the natural healing process, and will be replaced over time by cells from the receiver. The firststep in reconstructing a living organ by tissue engineering in vitro is the isolation and culture of each cell type. The most stringent conditions must be met during this step since it has a direct impact on the quality of the desired tissue engineered product. The ideal cellsource for tissue reconstructionshouldprovide celIswith extensive proliferation potential (self-renewal capacity) and appropriate differentiation abilities (able to give rise to a differentiated progeny). Each cell culture method must be characterized in such a manner to ensure that the isolation method and culture conditions (e.g., culturé medium and growth factors) during the growth as weil as during the maturation period are the most appropriate to conserve cell purity and phenotype. This chapter wilI focus on the various approachesdevelopedover the years by the Laboratoire d'Organogénèse Expérimental (LOEX) (Hôpital du Saint-Sacrement, Chauq, Quebec) to obtain three-dimensional tissues such as reconstructed epidermis, skin, blood vessel, comea, bronchi, and ligament.
  • PublicationRestreint
    Tissue-Engineered Ligament
    (Springer, 1997-01-01) Germain, Lucie; Rancourt, Denis; Auger, François A.; Normand, Albert; Goulet, Francine; Caron, Charlotte
    Tissue bioengineering has attracted considerable interest in the biological and medical fields, notably in orthopaedics. In United States alone at least 90 000 patients per year undergo ligament reconstruction [39]. As is often reported, in contrast with the medial collateral ligament, anterior cruciate ligament (ACL) regeneration is hampered in vivo [32, 42, 48]. In the young and active population reconstruction is often the best therapeutic option when indicated. Many clinical studies have attempted to develop new therapeutic alternatives such as allografts [4, 5] and synthetic prosthesis using carbon fiber, knitted Dacron and braided polypropylene (Ligament Augmentation Device) [13]. Patellar tendon and tensor fascia have frequently been used to replace torn ACL [5]. The success of the reconstruction depends on multiple factors such as the type of tissue used for the reconstruction, surgical technique, fixation of the graft; and revascularization of the transplanted tissues, progressively ensheathed in a vascular synovial envelope [5]. The tendon should finally acquire some ligament properties; and the word “ligamentization” was given by Amiel et al. [2] to describe this physiological phenomenon in vivo postgrafting.
  • PublicationRestreint
    Tissue engineering of human cornea
    (CRC Press, 2014-03-27) Guillemette, Maxime.; Giasson, Claude-J.; Guérin, Sylvain; Germain, Lucie; Auger, François A.; Gaudreault, Manon.; Proulx, Stéphanie; Carrier, Patrick; Chirila, Traian
    The cornea is a well-organized tissue composed of three cell types (epithelial, stromal and endothelial cells), each having an important role for its functionality. This chapter will address different tissue engineering approaches to the reconstruction of either partial or full-thickness living corneal substitutes that can be used either as in vitro models for woundhealing studies, or in vivo, eventually replacing the donor cornea for transplantation in humans. Isolation of the proper cells, followed by appropriate culture conditions, and assembly into a three-dimensional tissue construct, are the first steps required for producing a functional corneal substitute.