title: Shear resistance of endothelial cells in a pathological environment.
abstract: BACKGROUND
  Endothelial cells (EC) in vivo are strongly influenced by changes of the milieu exterieur. Under pathological conditions EC can become activated e.g. in hypoxic areas or during sepsis. In general, the endothelialization of implant materials is evaluated in vitro under physiological conditions. Though, in patients who receive implant materials pathological conditions are often present. An open question is therefore, how ECs seeded on a body foreign substrate behave in a pathologic microenvironment. In this in vitro study a microenvironment was created mimicking the conditions present in septic patients. To simulate this situation in vitro, serum of patients with septic shock was added to the culture medium of EC cultured on glass. The samples were sheared in a cone-plate rheometer (shear rate of 6 dyn/cm2) with subsequent analysis of the morphology, the microfilament organization and the shear resistance and compared to control cultures of EC without shock serum supplementation. Aim of the study was to investigate whether this in vitro model provides information about the functionality of an EC monolayer on a body foreign surface under pathological conditions.
  
  
  RESULTS
  Septic conditions induced severe changes of the morphology of the adherent cells: there was a strong induction of stress fibers. In addition, lots of cells or cell groups were detached visible as denuded areas in the EC monolayer. After shear stress exposure only 28.7% of EC seeded in cell medium supplemented with serum of septic patients remained adherent (control cells: 96.8%).
  
  
  CONCLUSIONS
  The study demonstrates that the microenvironment is of extreme importance for the behavior of EC and that in vivo pathologies can be simulated in vitro. This opens the possibility to evaluate new implant materials under physiological but more important also under certain pathological conditions - simulating the implant size and the disease of the host.
authors.affiliation: Institute of Biomaterial Science and Berlin-Brandenburg Center for Regenerative Therapies, Helmholtz-Zentrum Geesthacht, Teltow, Germany.
authors.forename: Anne
authors.initials: A
authors.lastname: Krüger-Genge
authors.affiliation: Institute of Biomaterial Science and Berlin-Brandenburg Center for Regenerative Therapies, Helmholtz-Zentrum Geesthacht, Teltow, Germany.|Institute of Clinical Hemostaseology and Transfusion Medicine, University of Saarland, Germany.
authors.forename: Friedrich
authors.initials: F
authors.lastname: Jung
authors.affiliation: Department of Biomaterials, Central Institute for Biomedical Engineering, University of Ulm, Ulm, Germany.
authors.forename: Rosemarie
authors.initials: R
authors.lastname: Fuhrmann
authors.affiliation: Department of Biomaterials, Central Institute for Biomedical Engineering, University of Ulm, Ulm, Germany.
authors.forename: Ralf-Peter
authors.initials: RP
authors.lastname: Franke
mesh_terms: D002478:Cells, Cultured; D003324:Coronary Artery Disease / Q000473:pathology*; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D013314:Stress, Mechanical
keywords: Endothelial cells; in vitro; sepsis; shear rate