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Biomolecules and Tissue Properties
Published in Joseph W. Freeman, Debabrata Banerjee, Building Tissues, 2018
Joseph W. Freeman, Debabrata Banerjee
Biglycan also interacts with transforming growth factor-β (TGF-β). TGF-β is a profibrotic key mediator in tissue fibrosis. TGF-β is one of the key profibrotic cytokines. It is chemotactic for fibroblasts, induces the synthesis of matrix proteins and glycoproteins, and inhibits collagen degradation by induction of protease inhibitors and reduction of metalloproteases. Biglycan has been shown to inhibit TGF-β in vitro. It has been suggested that biglycan (and other similar proteoglycans) may be able to sequester an overwhelming amount of TGF-β into the matrix and thereby control its biological effects.
Ex vivo study correlating the stiffness of the ovine patellar tendon to age and weight
Published in International Biomechanics, 2022
Françoise Kayser, Edoardo Bori, Sophie Fourny, Fanny Hontoir, Peter Clegg, Alexandra Dugdale, Bernardo Innocenti, Jean-Michel Vandeweerd
Proteoglycans also are involved in viscoelastic changes in aged tendons. Decorin is the most abundant proteoglycan in the small leucine-rich proteoglycan family (SLRP) in tendons. Decorin regulates the assembly of collagen I which is the primary structural unit and transmits mechanical force (Xu et al. 2018). The absence of decorin leads to an abnormal collagen fibrillogenesis, decreased tendon strength and stiffness (Danielson et al. 1997). Decorin and biglycan are essential regulators of collagen fibril and matrix assembly and provide overlapping functions rather than single deficiency-related abnormalities. A study in a both decorin and biglycan gene expression knockout mouse model showed changes in structural properties as a shift to larger diameter fibrils with increased heterogeneity, and altered mechanical properties as decreased stiffness (Robinson et al. 2017). A study carried out on old rats found decreased proteoglycan 4 and elastin mRNA expression in tendons was responsible for the increased tendon stiffness observed with ageing through reduced gliding properties of fascicular sheets (Kostrominova and Brooks 2013).
A human pericardium biopolymeric scaffold for autologous heart valve tissue engineering: cellular and extracellular matrix structure and biomechanical properties in comparison with a normal aortic heart valve
Published in Journal of Biomaterials Science, Polymer Edition, 2018
Frantisek Straka, David Schornik, Jaroslav Masin, Elena Filova, Tomas Mirejovsky, Zuzana Burdikova, Zdenek Svindrych, Hynek Chlup, Lukas Horny, Matej Daniel, Jiri Machac, Jelena Skibová, Jan Pirk, Lucie Bacakova
GAGs are formed from long unbranched chains of repeating disaccharides (N-acetylglucosamine or N-acetylgalactosamine and either uronic acid or galactose). Proteoglycans are formed when GAGs are connected by covalent linkage to a protein core [58]. GAGs (hyaluronan, heparin sulfate, chondroitin sulfate, dermatan sulfate, keratin sulfate) and proteoglycans (decorin, biglycan, versican) were found in all layers, but preferentially in the lamina spongiosa of the NAV leaflets. GAGs connected to fiber-fiber and fiber-matrix interactions at low force levels are able to hydrate the spongiosa layer by binding water molecules by negatively-charged sulfated and carboxylated polysaccharides, and they provide viscoelasticity by dampening the vibrations. In this way, GAGs allow for the compressibility of the leaflets and permit changes in the arrangement of the collagen and of the elastic fibers in the NAV leaflet during cuspal flexure [56,59,60]. GAGs were found uniformly in all layers of the fibrous HP, but in higher amounts in the inner serosal part.