Steady and pulsatile shear stress induce different three-dimensional endothelial networks through pseudopodium formation
Control of angiogenesis is a major challenge to promotion of vascularization in the field of tissue engineering. In particular, shear stress is recognized as an important mechanical factor controlling new vessel formation. However, the effects of steady and pulsatile shear stress on endothelial cell (EC) network formation remain unclear. Here, we systematically investigated their effects. Compared with pulsatile shear stress, steady shear stress at 1.0 Pa increased cell numbers in EC networks as well as the distribution of networks and pseudopodia in the deep range after 48 h. To further investigate the process of EC network growth, we focused on the effect of flow frequency on network elongation dynamics. Pulsatile shear stress at 1.0 Pa increased the extension and retraction velocities and separation of networks, resulting in the formation of unstable EC networks. In contrast, steady shear stress application resulted in the formation of extended and stable EC networks composed of many cells. Thus, two types of three-dimensional network growth were observed, depending on flow pulsatility. A combination of the type of ECs, such as aortic and microvascular ECs, and flow characteristics, such as flow magnitude and frequency, may have important implications for the construction of well-developed three-dimensional EC networks.
KeywordsFluid shear stress Endothelial cell Three-dimensional network Pseudopodium Angiogenesis
We thank Dr. Junichi Kasuya for helpful discussions. We acknowledge support to R.S. from the Japan Society for Promotion of Science (22680037).
- 11.Helmlinger G, Berk BC, Nerem RM. Calcium responses of endothelial cell monolayers subjected to pulsatile and steady laminar flow differ. Am J Physiol. 1995;269:C367–75.Google Scholar
- 22.Abe Y, Sudo R, Ikeda M, Tanishita K. Three-dimensional network formation of endothelial cells depended on shear stress. Trans Jpn Soc Mech Eng. 2010;76:1061–7.Google Scholar
- 28.Ito K, Sakamoto N, Ohashi T, Sato M. Effects of frequency of pulsatile flow on morphology and integrin expression of vascular endothelial cells. Technol Health Care. 2007;15:91–101.Google Scholar
- 40.Misra S, Fu AA, Puggioni A, Karimi KM, Mandrekar JN, Glockner JF, Juncos LA, Anwer B, McGuire AM, Mukhopadhyay D. Increased shear stress with upregulation of VEGF A and its receptors and MMP 2, MMP 9, and TIMP 1 in venous stenosis of hemodialysis grafts. Am J Physiol Heart Circ Physiol. 2008;294:H2219–30.CrossRefGoogle Scholar