title: Fibrin gels exhibit improved biological, structural, and mechanical properties compared with collagen gels in cell-based tendon tissue-engineered constructs.
abstract: The prevalence of tendon and ligament injuries and inadequacies of current treatments is driving the need for alternative strategies such as tissue engineering. Fibrin and collagen biopolymers have been popular materials for creating tissue-engineered constructs (TECs), as they exhibit advantages of biocompatibility and flexibility in construct design. Unfortunately, a few studies have directly compared these materials for tendon and ligament applications. Therefore, this study aims at determining how collagen versus fibrin hydrogels affect the biological, structural, and mechanical properties of TECs during formation in vitro. Our findings show that tendon and ligament progenitor cells seeded in fibrin constructs exhibit improved tenogenic gene expression patterns compared with their collagen-based counterparts for approximately 14 days in culture. Fibrin-based constructs also exhibit improved cell-derived collagen alignment, increased linear modulus (2.2-fold greater) compared with collagen-based constructs. Cyclic tensile loading, which promotes the maturation of tendon constructs in a previous work, exhibits a material-dependent effect in this study. Fibrin constructs show trending reductions in mechanical, biological, and structural properties, whereas collagen constructs only show improved tenogenic expression in the presence of mechanical stimulation. These findings highlight that components of the mechanical stimulus (e.g., strain amplitude or time of initiation) need to be tailored to the material and cell type. Given the improvements in tenogenic expression, extracellular matrix organization, and material properties during static culture, in vitro findings presented here suggest that fibrin-based constructs may be a more suitable alternative to collagen-based constructs for tissue-engineered tendon/ligament repair.
authors.affiliation: 1 Biomedical Engineering Program, Department of Biomedical, Chemical and Environmental Engineering, College of Engineering and Applied Science, University of Cincinnati , Cincinnati, Ohio.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Breidenbach
authors.forename: Nathaniel A
authors.initials: NA
authors.lastname: Dyment
authors.forename: Yinhui
authors.initials: Y
authors.lastname: Lu
authors.forename: Marepalli
authors.initials: M
authors.lastname: Rao
authors.forename: Jason T
authors.initials: JT
authors.lastname: Shearn
authors.forename: David W
authors.initials: DW
authors.lastname: Rowe
authors.forename: Karl E
authors.initials: KE
authors.lastname: Kadler
authors.forename: David L
authors.initials: DL
authors.lastname: Butler
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000138:chemical synthesis; D002454:Cell Differentiation; D049109:Cell Proliferation; D002478:Cells, Cultured; D003094:Collagen / Q000737:chemistry*; D019245:Compressive Strength / Q000502:physiology; D055119:Elastic Modulus / Q000502:physiology; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005337:Fibrin / Q000737:chemistry*; D048091:Guided Tissue Regeneration / Q000295:instrumentation* / Q000379:methods; D020100:Hydrogels / Q000737:chemistry; D008422:Materials Testing; D040542:Mechanotransduction, Cellular / Q000502:physiology; D051379:Mice; D013234:Stem Cells / Q000166:cytology* / Q000502:physiology; D013314:Stress, Mechanical; D013710:Tendons / Q000166:cytology* / Q000254:growth & development; D013718:Tensile Strength / Q000502:physiology; D023822:Tissue Engineering / Q000295:instrumentation* / Q000379:methods
chemical_list: D001672:Biocompatible Materials; D020100:Hydrogels; D005337:Fibrin; D003094:Collagen