A Delayed Type of Three-Dimensional Growth of Human Endothelial Cells Under Simulated Weightlessness

• Published in: Tissue engineering. Part A Vol. 15; no. 8; pp. 2267 - 2275
• Main Authors: Grimm, Daniela, Infanger, Manfred, Westphal, Kriss, Ulbrich, Claudia, Pietsch, Jessica, Kossmehl, Peter, Vadrucci, Sonia, Baatout, Sarah, Flick, Burkhard, Paul, Martin, Bauer, Johann
• Format: Journal Article
• Language: English
• Published: United States Mary Ann Liebert, Inc 01.08.2009
• Subjects: Actins - metabolism; Blotting, Western; Cell adhesion & migration; Cell growth; Cell Line; Cell Proliferation; Cellular biology; Culture Media; Cytoskeleton - metabolism; Cytoskeleton - ultrastructure; Endothelial Cells - cytology; Endothelial Cells - enzymology; Endothelial Cells - ultrastructure; Extracellular Matrix - metabolism; Extracellular Matrix - ultrastructure; Extracellular Matrix Proteins - metabolism; Gravity; Humans; Matrix Metalloproteinase 2 - metabolism; Neovascularization, Physiologic; Original Articles; Tissue engineering; Tissue Inhibitor of Metalloproteinase-1 - metabolism; Tubulin - metabolism; Weightlessness; Weightlessness Simulation
• ISSN: 1937-3341; 1937-335X
• DOI: 10.1089/ten.tea.2008.0576

Endothelial cells (ECs) form three-dimensional (3D) aggregates without any scaffold when they are exposed to microgravity simulated by a random positioning machine (RPM) but not under static conditions at gravity. Here we describe a delayed type of formation of 3D structures of ECs that was initiated when ECs cultured on a desktop RPM remained adherent for the first 5 days but spread over neighboring adherent cells, forming little colonies. After 2 weeks, tube-like structures (TSs) became visible in these cultures. They included a lumen, and they elongated during another 2 weeks of culturing. The walls of these TSs consisted mainly of single-layered ECs, which had produced significantly more β 1 -integrin, laminin, fibronectin, and alpha-tubulin than ECs simultaneously grown adhering to the culture dishes under microgravity or normal gravity. The amount of actin protein was similar in ECs incorporated in TSs and in ECs growing at gravity. The ratio of tissue inhibitor of metalloproteinases-1 to matrix metalloproteinase-2 found in the supernatants was lower at the seventh than at the 28th day of culturing. These results suggest that culturing ECs under conditions of modeled gravitational unloading represents a new technique for studying the formation of tubes that resemble vascular intimas.