TY - JOUR
T1 - The influence of collagen-glycosaminoglycan scaffold relative density and microstructural anisotropy on tenocyte bioactivity and transcriptomic stability
AU - Caliari, Steven R.
AU - Weisgerber, Daniel W.
AU - Ramirez, Manuel A.
AU - Kelkhoff, Douglas O.
AU - Harley, Brendan A.C.
N1 - Funding Information:
The authors would like to acknowledge Dr. Allison Stewart (Veterinary Sciences, UIUC) for providing equine tendon cells, Karen Doty (Veterinary Sciences, UIUC) for sectioning of GMA embedded samples, Donna Epps for sectioning and staining of paraffin embedded samples, and the IGB Core Facilities for the use of their real-time PCR system. We are grateful for the funding for this study provided by the Chemistry–Biology Interface Training Program NIH NIGMS T32GM070421 (SRC) , the Chemical and Biomolecular Engineering Dept. (BAH) , and the Institute for Genomic Biology (BAH) at the University of Illinois at Urbana-Champaign. This research was carried out in part in the Frederick Seitz Materials Research Laboratory Central Facilities, University of Illinois, which is partially supported by the US Department of Energy under grants DE-FG02-07ER46453 and DE-FG02-07ER46471 .
PY - 2012/7
Y1 - 2012/7
N2 - Biomaterials for orthopedic tissue engineering must balance mechanical and bioactivity concerns. This work describes the fabrication of a homologous series of anisotropic collagen-GAG (CG) scaffolds with aligned tracks of ellipsoidal pores but increasing relative densities (ρ */ρ s), and we report the role scaffold relative density plays in directing tenocyte bioactivity. Scaffold permeability and mechanical properties, both in tension and compression, were significantly influenced by relative density in a manner predicted by cellular solids models. Equine tenocytes showed greater levels of attachment, metabolic activity, soluble collagen synthesis, and alignment as well as less cell-mediated scaffold contraction in anisotropic CG scaffolds of increasing relative density. Notably, the lowest density scaffolds experienced significant cell-mediated contraction with associated decreases in tenocyte number as well as loss of microstructural integrity, aligned contact guidance cues, and preferential tenocyte orientation over a 14 day culture period. Gene expression analyses suggested tenocyte de-differentiation in the lowest density scaffold while indicating that the highest density scaffold supported significant increases in COMP (4-fold), tenascin-C (3-fold), and scleraxis (15-fold) expression as well as significant decreases in MMP-1 (9-fold) and MMP-13 (13-fold) expression on day 14. These results suggest that anisotropic scaffold relative density can help to modulate the maintenance of a more tendon-like microenvironment and aid long-term tenocyte transcriptomic stability. Overall, this work demonstrates that relative density is a critical scaffold parameter, not only for insuring mechanical competence, but also for directing cell transcriptomic stability and behavior.
AB - Biomaterials for orthopedic tissue engineering must balance mechanical and bioactivity concerns. This work describes the fabrication of a homologous series of anisotropic collagen-GAG (CG) scaffolds with aligned tracks of ellipsoidal pores but increasing relative densities (ρ */ρ s), and we report the role scaffold relative density plays in directing tenocyte bioactivity. Scaffold permeability and mechanical properties, both in tension and compression, were significantly influenced by relative density in a manner predicted by cellular solids models. Equine tenocytes showed greater levels of attachment, metabolic activity, soluble collagen synthesis, and alignment as well as less cell-mediated scaffold contraction in anisotropic CG scaffolds of increasing relative density. Notably, the lowest density scaffolds experienced significant cell-mediated contraction with associated decreases in tenocyte number as well as loss of microstructural integrity, aligned contact guidance cues, and preferential tenocyte orientation over a 14 day culture period. Gene expression analyses suggested tenocyte de-differentiation in the lowest density scaffold while indicating that the highest density scaffold supported significant increases in COMP (4-fold), tenascin-C (3-fold), and scleraxis (15-fold) expression as well as significant decreases in MMP-1 (9-fold) and MMP-13 (13-fold) expression on day 14. These results suggest that anisotropic scaffold relative density can help to modulate the maintenance of a more tendon-like microenvironment and aid long-term tenocyte transcriptomic stability. Overall, this work demonstrates that relative density is a critical scaffold parameter, not only for insuring mechanical competence, but also for directing cell transcriptomic stability and behavior.
KW - Collagen
KW - Gene expression
KW - Relative density
KW - Scaffold
KW - Tendon
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U2 - 10.1016/j.jmbbm.2011.12.004
DO - 10.1016/j.jmbbm.2011.12.004
M3 - Article
C2 - 22658152
AN - SCOPUS:84861676302
SN - 1751-6161
VL - 11
SP - 27
EP - 40
JO - Journal of the Mechanical Behavior of Biomedical Materials
JF - Journal of the Mechanical Behavior of Biomedical Materials
ER -