Abstract
Angiogenesis is the growth of new capillaries from existing vasculature. Vascular network formation is known to be regulated by the biophysical and biochemical signals emanating from the microenvironment. However, it is not clear how endothelial cells integrate these signals to drive the capillary morphogenesis. In this study, human umbilical endothelial cells (HUVECs) were seeded on scaffolds with varying stiffness and capillary formation was quantified. Our study revealed that cells formed well defined networks on compliant gels. Increase in stiffness resulted in a decrease in sprouting. VEGF was encapsulated within the scaffolds at concentrations ranging from 0 to 100 ng/mL to investigate the interplay between VEGF concentration profiles and matrix stiffness in guiding network formation. Quantitative analysis revealed that while VEGF disrupted sprout formation on compliant substrates, it elicited a sprouting response in cells seeded on scaffolds of intermediate rigidity. Additionally, we also observed that a minimum cell density is required for the formation of well-connected vascular networks.
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Acknowledgments
The authors would like to thank Dr. Wonsuk Kim and Jacob Mack for their help in performing the mechanical testing of the samples and Mao Ye for his help in SEM imaging. We would also like to thank University of Michigan-Dearborn and University of Michigan-Ann Arbor: Office of the Vice President for Research for the financial support.
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Associate Editor K. A. Athanasiou oversaw the review of this article.
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Wu, Y., Al-Ameen, M.A. & Ghosh, G. Integrated Effects of Matrix Mechanics and Vascular Endothelial Growth Factor (VEGF) on Capillary Sprouting. Ann Biomed Eng 42, 1024–1036 (2014). https://doi.org/10.1007/s10439-014-0987-7
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DOI: https://doi.org/10.1007/s10439-014-0987-7