Dresden 2011 – scientific programme
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BP: Fachverband Biologische Physik
BP 5: Tissue Dynamics \& Developmental Processes
BP 5.4: Talk
Monday, March 14, 2011, 15:00–15:15, ZEU 250
Fluidization of tissues due to cell division and apoptosis — •Jonas Ranft1,2, Markus Basan1, Jens Elgeti1, Jean-François Joanny1, Jacques Prost3, and Frank Jülicher2 — 1Institut Curie, 26 rue d’Ulm, 75005 Paris, France — 2Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Str. 38, 01187 Dresden, Germany — 3ESPCI, 10 rue Vauquelin, 75005 Paris, France
Throughout development, tissues grow due to continuous cell division. In later stages, tissues can reach a homeostatic state in which cell division and cell death balance on average. In addition to genetic regulation, the mechanics of tissues play an important role in these processes. We develop a continuum description of tissue dynamics in order to account for the stress distribution and cell flows on large scales [1]. In the absence of cell division and apoptosis, we consider the tissue to behave as an elastic solid. Cell division and apoptosis introduce stress sources which in general are anisotropic. By combining cell number balance with dynamic equations for the stress source, we show that the tissue effectively behaves as a visco-elastic fluid with a relaxation time set by the rates of division and apoptosis. We find that close to the homeostatic state, the compressional modulus of the tissue vanishes on long time scales. We discuss the effects of fluctuations in cell division and apoptosis and compare our results to simulations of multicellular systems. This approach can be extended to a two-component description of tissues that takes the extracellular fluid explicitly into account.
[1] Ranft et al., PNAS, 2010 Nov 15. (Epub ahead of print)