We study the long-range dynamics induced by cell division in an endothelial monolayer under non-flow conditions. In healthy blood vessels with a laminar blood flow, the endothelial cell division rate is low, only sufficient to replace apoptotic cells. The division rate increases significantly when the flow is turbulent or stopped. We find that cell divisions induce long-range, well-ordered vortex patterns extending several cell diameters away from the division site. We model these observations by a hydrodynamic continuum model simulating division as a local pressure increase in a non-nematic, meso-scale turbulent state. In order to describe the injected energy by cell motion in the tissue we assume an effective negative local viscosity stabilized by a higher order term. The effective negative viscosity thus models the motion of individual cells 'against' the viscous forces.

Mogens H. Jensen is a Professor of Biophysics and Complex Systems, at the Niels Bohr Institute, University of Copenhagen and the Head of Biocomplexity Section. He received his PhD under supervision of Prof. P. Bak in 1984 and was a postdoc with Prof. L. Kadanoff at University of Chicago. Prof. Jensen is Secretary General of Royal Danish Academy of Science and Letters and has published 230 papers. He has received the Physics Prize of Norway in 2011, the Ole Roemer Prize from the Royal Danish Academy of Sciences in 1993.