TY - JOUR
T1 - The effect of matrix density on the regulation of 3-D capillary morphogenesis
AU - Ghajar, Cyrus M.
AU - Chen, Xiaofang
AU - Harris, Joseph W.
AU - Suresh, Vinod
AU - Hughes, Christopher C.W.
AU - Jeon, Noo Li
AU - Putnam, Andrew J.
AU - George, Steven
PY - 2008/3/1
Y1 - 2008/3/1
N2 - The means by which extracellular matrix density regulates three-dimensional capillary morphogenesis is unclear. To study this phenomenon, we utilized a fibrin-based in vitro assay in which a fibroblast monolayer is plated atop a fibrin gel ∼2.5 mm away from endothelial cell-coated beads within the matrix. Increasing fibrin density from 2.5 to 10 mg/ml resulted in a threefold reduction in capillary network formation. However, distributing fibroblasts throughout the matrix completely eliminated this inhibitory effect, resulting in robustly vascularized matrices suitable for in vivo applications, as functional anastomoses formed between the implanted tissues and host vasculature when implanted into immune-compromised mice. Dense matrices did not stimulate fibroblast-mediated matrix remodeling: differentiation into myofibroblasts, matrix production, and protease secretion were not enhanced by the dense condition. Instead, quantifying diffusivity of FITC-dextran (molecular mass 10, 40, 70, and 150 kDa) through fibrin revealed a two- to threefold decrease within the 10 mg/ml matrices. Thus, distributing a proangiogenic source (fibroblasts) throughout the matrix stimulates capillary network formation by overcoming this diffusion restriction due to significantly reduced diffusion distances. Although roles for matrix stiffness and ligand binding density have previously been identified, our results emphasize the importance of diffusion restrictions in limiting capillary morphogenesis.
AB - The means by which extracellular matrix density regulates three-dimensional capillary morphogenesis is unclear. To study this phenomenon, we utilized a fibrin-based in vitro assay in which a fibroblast monolayer is plated atop a fibrin gel ∼2.5 mm away from endothelial cell-coated beads within the matrix. Increasing fibrin density from 2.5 to 10 mg/ml resulted in a threefold reduction in capillary network formation. However, distributing fibroblasts throughout the matrix completely eliminated this inhibitory effect, resulting in robustly vascularized matrices suitable for in vivo applications, as functional anastomoses formed between the implanted tissues and host vasculature when implanted into immune-compromised mice. Dense matrices did not stimulate fibroblast-mediated matrix remodeling: differentiation into myofibroblasts, matrix production, and protease secretion were not enhanced by the dense condition. Instead, quantifying diffusivity of FITC-dextran (molecular mass 10, 40, 70, and 150 kDa) through fibrin revealed a two- to threefold decrease within the 10 mg/ml matrices. Thus, distributing a proangiogenic source (fibroblasts) throughout the matrix stimulates capillary network formation by overcoming this diffusion restriction due to significantly reduced diffusion distances. Although roles for matrix stiffness and ligand binding density have previously been identified, our results emphasize the importance of diffusion restrictions in limiting capillary morphogenesis.
UR - http://www.scopus.com/inward/record.url?scp=41449114479&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=41449114479&partnerID=8YFLogxK
U2 - 10.1529/biophysj.107.120774
DO - 10.1529/biophysj.107.120774
M3 - Article
C2 - 17993494
AN - SCOPUS:41449114479
VL - 94
SP - 1930
EP - 1941
JO - Biophysical Journal
JF - Biophysical Journal
SN - 0006-3495
IS - 5
ER -