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Séminaires MSC
"Matière et Systèmes Complexes"

                      

Lundi 17 décembre 2007 à 11h30
Bâtiment Condorcet, 4ème étage, salle 454 A.


Annemiek Cornelissen
(MSC, Université Paris-Diderot)


Physical self-organised mechanisms in vascular morphogenesis and tissue growth

Vascular morphogenesis, and in more general tissue morphogenesis, requires mechanical forces to position cells and shape the developing organs. In a simplified picture, the addition of all incremental pushes of migrating, dilating and  proliferating cells generates a mechanical stress gradient inside the growing tissue. Such stress gradient can on the one hand serve as a signal for cellular mechanotransducers resulting in gene activation. On the other hand, the dynamically  changing landscape of stress guides the displacing, newly created, growing cellsin an auto-organizing way.

To address the auto-organizing role of stress gradients for vascular morphogenesis, we observed in vivo vascular development in the chicken embryo yolk-sac and in jellyfish (Aurelia Aurita) using video-microscopy. Applying simple mathematical  models, tissue deformation is related to vascular patterning, showing that in-tissue stress gradients are closely associated with the paths taken by the blood vessels.

The second part of my presentation will deal with vascular diameter adaptation and its consequences for oxygen delivery to the tissue. Vascular diameters adapt in response to hemodynamic, metabolic and conducted stimuli. I will show how  these mechanisms work in concert to adequately supply healthy tissue with blood and how this concerted action is impaired in tumor vascular networks.