title: Effect of shear stress on microvessel network formation of endothelial cells with in vitro three-dimensional model.
abstract: Shear stress stimulus is expected to enhance angiogenesis, the formation of microvessels. We determined the effect of shear stress stimulus on three-dimensional microvessel formation in vitro. Bovine pulmonary microvascular endothelial cells were seeded onto collagen gels with basic fibroblast growth factor to make a microvessel formation model. We observed this model in detail using phase-contrast microscopy, confocal laser scanning microscopy, and electron microscopy. The results show that cells invaded the collagen gel and reconstructed the tubular structures, containing a clearly defined lumen consisting of multiple cells. The model was placed in a parallel-plate flow chamber. A laminar shear stress of 0.3 Pa was applied to the surfaces of the cells for 48 h. Promotion of microvessel network formation was detectable after approximately 10 h in the flow chamber. After 48 h, the length of networks exposed to shear stress was 6.17 (+/-0.59) times longer than at the initial state, whereas the length of networks not exposed to shear stress was only 3.30 (+/-0.41) times longer. The number of bifurcations and endpoints increased for networks exposed to shear stress, whereas the number of bifurcations alone increased for networks not exposed to shear stress. These results demonstrate that shear stress applied to the surfaces of endothelial cells on collagen gel promotes the growth of microvessel network formation in the gel and expands the network because of repeated bifurcation and elongation.
authors.affiliation: School of Fundamental Science and Technology, Keio University, Yokohama 223-8522, Japan. akinori@tani.sd.keio.ac.jp
authors.forename: Akinori
authors.initials: A
authors.lastname: Ueda
authors.forename: Masaki
authors.initials: M
authors.lastname: Koga
authors.forename: Mariko
authors.initials: M
authors.lastname: Ikeda
authors.forename: Susumu
authors.initials: S
authors.lastname: Kudo
authors.forename: Kazuo
authors.initials: K
authors.lastname: Tanishita
mesh_terms: D000818:Animals; D002417:Cattle; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D003094:Collagen; D004730:Endothelium, Vascular / Q000166:cytology / Q000502:physiology*; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D005782:Gels; D008833:Microcirculation / Q000502:physiology; D008955:Models, Cardiovascular; D018919:Neovascularization, Physiologic; D011652:Pulmonary Circulation / Q000502:physiology*; D013314:Stress, Mechanical; D013997:Time Factors
chemical_list: D005782:Gels; D016222:Fibroblast Growth Factor 2; D003094:Collagen