title: A delayed type of three-dimensional growth of human endothelial cells under simulated weightlessness.
abstract: 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 beta(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.
authors.affiliation: Institute of Clinical Pharmacology and Toxicology, CBF/CCM, Charité-Universitätsmedizin , Berlin, Berlin, Germany. daniela.grimm@farm.au.dk
authors.forename: Daniela
authors.initials: D
authors.lastname: Grimm
authors.forename: Manfred
authors.initials: M
authors.lastname: Infanger
authors.forename: Kriss
authors.initials: K
authors.lastname: Westphal
authors.forename: Claudia
authors.initials: C
authors.lastname: Ulbrich
authors.forename: Jessica
authors.initials: J
authors.lastname: Pietsch
authors.forename: Peter
authors.initials: P
authors.lastname: Kossmehl
authors.forename: Sonia
authors.initials: S
authors.lastname: Vadrucci
authors.forename: Sarah
authors.initials: S
authors.lastname: Baatout
authors.forename: Burkhard
authors.initials: B
authors.lastname: Flick
authors.forename: Martin
authors.initials: M
authors.lastname: Paul
authors.forename: Johann
authors.initials: J
authors.lastname: Bauer
mesh_terms: D000199:Actins / Q000378:metabolism; D015153:Blotting, Western; D002460:Cell Line; D049109:Cell Proliferation; D003470:Culture Media; D003599:Cytoskeleton / Q000378:metabolism / Q000648:ultrastructure; D042783:Endothelial Cells / Q000166:cytology* / Q000201:enzymology / Q000648:ultrastructure; D005109:Extracellular Matrix / Q000378:metabolism / Q000648:ultrastructure; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D006801:Humans; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D018919:Neovascularization, Physiologic; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism; D014404:Tubulin / Q000378:metabolism; D014893:Weightlessness; D018474:Weightlessness Simulation
chemical_list: D000199:Actins; D003470:Culture Media; D016326:Extracellular Matrix Proteins; D019715:Tissue Inhibitor of Metalloproteinase-1; D014404:Tubulin; D020778:Matrix Metalloproteinase 2