title: Collagen fibril structure is affected by collagen concentration and decorin.
abstract: Collagen fibrils were obtained in vitro by aggregation from acid-soluble type I collagen at different initial concentrations and with the addition of decorin core or intact decorin. All specimens were observed by scanning electron microscopy and atomic force microscopy. In line with the findings of other authors, lacking decorin, collagen fibrils undergo an extensive lateral association leading to the formation of a continuous three-dimensional network. The addition of intact decorin or decorin core was equally effective in preventing lateral fusion and restoring the normal fibril appearance. In addition, the fibril diameter was clearly dependent on the initial collagen concentration but not on the presence/absence of proteoglycans. An unusual fibril structure was observed as a result of a very low initial collagen concentration, leading to the formation of huge, irregular superfibrils apparently formed by the lateral coalescence of lesser fibrils, and with a distinctive coil-structured surface. Spots of incomplete fibrillogenesis were occasionally found, where all fibrils appeared made of individual, interwined subfibrils, confirming the presence of a hierarchical association mechanism.
authors.affiliation: Department of Human Morphology, Insubria University, Varese, Italy. mario.raspanti@uninsubria.it
authors.forename: Mario
authors.initials: M
authors.lastname: Raspanti
authors.forename: Manuela
authors.initials: M
authors.lastname: Viola
authors.forename: Myriam
authors.initials: M
authors.lastname: Sonaggere
authors.forename: Maria Enrica
authors.initials: ME
authors.lastname: Tira
authors.forename: Ruggero
authors.initials: R
authors.lastname: Tenni
mesh_terms: D003094:Collagen / Q000737:chemistry* / Q000648:ultrastructure; D058575:Decorin; D016326:Extracellular Matrix Proteins / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D011487:Protein Conformation; D011509:Proteoglycans / Q000737:chemistry*
chemical_list: C546878:DCN protein, human; D058575:Decorin; D016326:Extracellular Matrix Proteins; D011509:Proteoglycans; D003094:Collagen