Personne :
Lefèvre, Thierry

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Adresse électronique
Date de naissance
Projets de recherche
Structures organisationnelles
Nom de famille
Université Laval. Département de chimie
Identifiant Canadiana

Résultats de recherche

Voici les éléments 1 - 2 sur 2
  • Publication
    Accès libre
    Using infrared and raman microspectroscopies to compare ex vivo involved psoriatic skin with normal human skin
    (SPIE, 2015-06-17) Lefèvre, Thierry; Auger, Michèle; Laroche, Gaétan; Leroy, Marie; Pouliot, Roxane
    Psoriasis is a chronic dermatosis that affects around 3% of the world’s population. The etiology of this autoimmune pathology is not completely understood. The barrier function of psoriatic skin is known to be strongly altered, but the structural modifications at the origin of this dysfunction are not clear. To develop strategies to reduce symptoms of psoriasis or adequate substitutes for modeling, a deep understanding of the organization of psoriatic skin at a molecular level is required. Infrared and Raman microspectroscopies have been used to obtain direct molecular-level information on psoriatic and healthy human skin biopsies. From the intensities and positions of specific vibrational bands, the lipid and protein distribution and the lipid order have been mapped in the different layers of the skin. Results showed a similar distribution of lipids and collagen for normal and psoriatic human skin. However, psoriatic skin is characterized by heterogeneity in lipid/protein composition at the micrometer scale, a reduction in the definition of skin layer boundaries and a decrease in lipid chain order in the stratum corneum as compared to normal skin. A global decrease of the structural organization is exhibited in psoriatic skin that is compatible with an alteration of its barrier properties.
  • Publication
    Accès libre
    A comparative study between human skin substitutes and normal human skin using Raman microspectroscopy
    (Minerals, Metals and Materials Society, 2014-02-12) Labbé, Jean-François; Jean, Jessica; Auger, Michèle; Ouellet, Marise; Laroche, Gaétan; Leroy, Marie; Pouliot, Roxane; Lefèvre, Thierry
    Research in the field of bioengineered skin substitutes is motivated by the need to find new dressings for people affected by skin injuries (burns, diabetic ulcers), and to develop adequate skin models to test new formulations developed in vitro. Thanks to advances in tissue engineering, it is now possible to produce human skin substitutes without any exogenous material, using the self-assembly method developed by the Laboratoire d’Organogénèse Expérimentale. These human skin substitutes consist of a dermis and a stratified epidermis (stratum corneum and living epidermis). Raman microspectroscopy has been used to characterize and compare the molecular organization of skin substitutes with normal human skin. Our results confirm that the stratum corneum is a layer rich in lipids which are well ordered (trans conformers) in both substitutes and normal human skin. The amount of lipids decreases and more gauche conformers appear in the living epidermis in both cases. However, the results also show that there are fewer lipids in the substitutes and that the lipids are more organized in the normal human skin. Concerning the secondary structure of proteins and protein content, the data show that they are similar in the substitutes and in the normal human skin. In fact, the epidermis is rich in α-keratin, whereas the dermis contains mainly type I collagen.