Laboratoire Matière et Systèmes Complexes

Olivier THEODOLY,

Laboratoire Adhésion & Inflammation (LAI), INSERM/CNR RS/AMU, Marseille.

Leukocytes recruitment in the microcirculation

In collaboration with : P Preira, P Nègre, A Lellouch, MP Valignat, P Bongrand (from LAI) ; J Bico (from ESPCI), L Papazian (from AP-HM) ; A Asnacios, F Gallet, S Henon (from MSC).

During the immunological response, leukoytes are recruited from the blood system toward inflammatory zones via complex cascade of events that are difficult to investigate in vivo. After exiting the cappilary bed, leukocytes stop by adherence in the post-capillary veinules, migrate on the vessels walls and eventually cross the endothelium. In an attempt to decipher some mechanical aspects involved in normal and pathological recruitment processes, we use in vitro approaches to control the cellular micro-environments. We investigated the role of adhesion, friction, and deformability in the pathological arrest of leukocytes in the blood cappilaries of the lungs, which is the triggering event of the acute respiratory distress syndrome (ARDS). We also analyzed the role of the hydrodynamic stress on the migration of leukocytes at the inner surface of blood vessels and show how normal T-lymphocyte crawl upstream in opposition to the exerted force.

(left) Forced passage of a circulating leukocyte in a 4µm wide constriction ; (right) Migration of an adherent leukocyte under hydrodynamic and magnetic actuation.