title: Fibroblast viability and phenotypic changes within glycated stiffened three-dimensional collagen matrices.
abstract: BACKGROUND
  There is growing interest in the development of cell culture assays that enable the rigidity of the extracellular matrix to be increased. A promising approach is based on three-dimensional collagen type I matrices that are stiffened by cross-linking through non-enzymatic glycation with reducing sugars.
  
  
  METHODS
  The present study evaluated the biomechanical changes in the non-enzymatically glycated type I collagen matrices, including collagen organization, the advanced glycation end products formation and stiffness achievement. Gels were glycated with ribose at different concentrations (0, 5, 15, 30 and 240 mM). The viability and the phenotypic changes of primary human lung fibroblasts cultured within the non-enzymatically glycated gels were also evaluated along three consecutive weeks. Statistical tests used for data analyze were Mann-Whitney U, Kruskal Wallis, Student's t-test, two-way ANOVA, multivariate ANOVA, linear regression test and mixed linear model.
  
  
  RESULTS
  Our findings indicated that the process of collagen glycation increases the stiffness of the matrices and generates advanced glycation end products in a ribose concentration-dependent manner. Furthermore, we identified optimal ribose concentrations and media conditions for cell viability and growth within the glycated matrices. The microenvironment of this collagen based three-dimensional culture induces α-smooth muscle actin and tenascin-C fibroblast protein expression. Finally, a progressive contractile phenotype cell differentiation was associated with the contraction of these gels.
  
  
  CONCLUSIONS
  The use of non-enzymatic glycation with a low ribose concentration may provide a suitable model with a mechanic and oxidative modified environment with cells embedded in it, which allowed cell proliferation and induced fibroblast phenotypic changes. Such culture model could be appropriate for investigations of the behavior and phenotypic changes in cells that occur during lung fibrosis as well as for testing different antifibrotic therapies in vitro.
authors.affiliation: Department of Pneumology, Unit of Interstitial Lung Diseases, University Hospital of Bellvitge, Barcelona, Spain. vvicens@hotmail.com.|Pneumology Research Group, IDIBELL, University of Barcelona, Barcelona, Spain. vvicens@hotmail.com.
authors.forename: Vanesa
authors.initials: V
authors.lastname: Vicens-Zygmunt
authors.affiliation: Pneumology Research Group, IDIBELL, University of Barcelona, Barcelona, Spain. susanna.estany@gmail.com.
authors.forename: Susanna
authors.initials: S
authors.lastname: Estany
authors.affiliation: Unit of Biophysics and Bioengineering, University of Barcelona, Barcelona, Spain. adai.colom@unige.ch.|Department of Biochemistry, University of Geneva, Science II, Geneva, Switzerland. adai.colom@unige.ch.
authors.forename: Adai
authors.initials: A
authors.lastname: Colom
authors.affiliation: Pneumology Research Group, IDIBELL, University of Barcelona, Barcelona, Spain. anaworboys@yahoo.es.
authors.forename: Ana
authors.initials: A
authors.lastname: Montes-Worboys
authors.affiliation: Pneumology Research Group, IDIBELL, University of Barcelona, Barcelona, Spain. mach_8990@hotmail.com.
authors.forename: Carlos
authors.initials: C
authors.lastname: Machahua
authors.affiliation: Department of Preventive Medicine, University Hospital of Bellvitge, Barcelona, Spain. sanabria.andreajuliana@gmail.com.
authors.forename: Andrea Juliana
authors.initials: AJ
authors.lastname: Sanabria
authors.affiliation: Pneumology Research Group, IDIBELL, University of Barcelona, Barcelona, Spain. rllatjos@bellvitgehospital.cat.|Department of Pathology, University Hospital of Bellvitge, Barcelona, Spain. rllatjos@bellvitgehospital.cat.
authors.forename: Roger
authors.initials: R
authors.lastname: Llatjos
authors.affiliation: Department of Thoracic Surgery, University Hospital of Bellvitge, Barcelona, Spain. iescobar@bellvitgehospital.cat.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Escobar
authors.affiliation: Department of Pneumology, Unit of Interstitial Lung Diseases, University Hospital of Bellvitge, Barcelona, Spain. fmanresa@bellvitgehospital.cat.|Pneumology Research Group, IDIBELL, University of Barcelona, Barcelona, Spain. fmanresa@bellvitgehospital.cat.
authors.forename: Frederic
authors.initials: F
authors.lastname: Manresa
authors.affiliation: Department of Pneumology, Unit of Interstitial Lung Diseases, University Hospital of Bellvitge, Barcelona, Spain. jodorca@bellvitgehospital.cat.|Pneumology Research Group, IDIBELL, University of Barcelona, Barcelona, Spain. jodorca@bellvitgehospital.cat.
authors.forename: Jordi
authors.initials: J
authors.lastname: Dorca
authors.affiliation: Unit of Biophysics and Bioengineering, University of Barcelona, Barcelona, Spain. dnavajas@ub.edu.|Research Network in Respiratory Diseases (Centro de Investigación Biomédica en Red (CIBER) de Enfermedades Respiratorias), ISCIII, Barcelona, Spain. dnavajas@ub.edu.
authors.forename: Daniel
authors.initials: D
authors.lastname: Navajas
authors.affiliation: Unit of Biophysics and Bioengineering, University of Barcelona, Barcelona, Spain. jalcaraz@ub.edu.|Research Network in Respiratory Diseases (Centro de Investigación Biomédica en Red (CIBER) de Enfermedades Respiratorias), ISCIII, Barcelona, Spain. jalcaraz@ub.edu.
authors.forename: Jordi
authors.initials: J
authors.lastname: Alcaraz
authors.affiliation: Department of Pneumology, Unit of Interstitial Lung Diseases, University Hospital of Bellvitge, Barcelona, Spain. mariamolinamolina@hotmail.com.|Pneumology Research Group, IDIBELL, University of Barcelona, Barcelona, Spain. mariamolinamolina@hotmail.com.|Research Network in Respiratory Diseases (Centro de Investigación Biomédica en Red (CIBER) de Enfermedades Respiratorias), ISCIII, Barcelona, Spain. mariamolinamolina@hotmail.com.
authors.forename: Maria
authors.initials: M
authors.lastname: Molina-Molina
mesh_terms: D018929:Cell Culture Techniques / Q000379:methods; D002470:Cell Survival / Q000502:physiology*; D002478:Cells, Cultured; D003094:Collagen / Q000737:chemistry* / Q000502:physiology*; D005109:Extracellular Matrix / Q000737:chemistry / Q000502:physiology; D005347:Fibroblasts / Q000502:physiology*; D006031:Glycosylation; D006801:Humans; D008168:Lung / Q000166:cytology / Q000502:physiology; D010641:Phenotype
chemical_list: D003094:Collagen