title: A microscopic and macroscopic study of aging collagen on its molecular structure, mechanical properties, and cellular response.
abstract: During aging, collagen structure changes, detrimentally affecting tissues' biophysical and biomechanical properties due to an accumulation of advanced glycation end-products (AGEs). In this investigation, we conducted a parallel study of microscopic and macroscopic properties of different-aged collagens from newborn to 2-yr-old rats, to examine the effect of aging on fibrillogenesis, mechanical and contractile properties of reconstituted hydrogels from these collagens seeded with or without fibroblasts. In addition to fibrillogenesis of collagen under the conventional conditions, some fibrillogenesis was conducted alongside a 12-T magnetic field, and gelation rate and AGE content were measured. A nondestructive indentation technique and optical coherence tomography were used to determine the elastic modulus and dimensional changes, respectively. It was revealed that in comparison to younger specimens, older collagens exhibited higher viscosity, faster gelation rates, and a higher AGE-specific fluorescence. Exceptionally, only young collagens formed highly aligned fibrils under magnetic fields. The youngest collagen demonstrated a higher elastic modulus and contraction in comparison to the older collagen. We conclude that aging changes collagen monomer structure, which considerably affects the fibrillogenesis process, the architecture of the resulting collagen fibers and the global network, and the macroscopic properties of the formed constructs.
authors.affiliation: 1Institute for Science and Technology in Medicine, Keele University, Stoke-on-Trent, ST4 7QB, UK. y.yang@keele.ac.uk.
authors.forename: Samantha L
authors.initials: SL
authors.lastname: Wilson
authors.forename: Marie
authors.initials: M
authors.lastname: Guilbert
authors.forename: Josep
authors.initials: J
authors.lastname: Sulé-Suso
authors.forename: Jim
authors.initials: J
authors.lastname: Torbet
authors.forename: Pierre
authors.initials: P
authors.lastname: Jeannesson
authors.forename: Ganesh D
authors.initials: GD
authors.lastname: Sockalingum
authors.forename: Ying
authors.initials: Y
authors.lastname: Yang
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D003094:Collagen / Q000737:chemistry* / Q000378:metabolism*; D017127:Glycation End Products, Advanced / Q000378:metabolism; D015394:Molecular Structure; D051381:Rats
chemical_list: D017127:Glycation End Products, Advanced; D003094:Collagen
keywords: AGEs; contraction; elastic modulus; fiber alignment; fibrillogenesis