Microangiectasias: structural regulators of lymphocyte transmigration.
The migration of lymphocytes into inflammatory tissue requires the migrating cell to overcome mechanical forces produced by blood flow. A generally accepted hypothesis is that these forces are overcome by a multistep sequence of adhesive interactions between lymphocytes and endothelial cells. This hypothesis has been recently challenged by results demonstrating wall shear stress on the order of 20 dyn/cm(2) in vivo and infrequent lymphocyte-endothelial adhesion at wall shear stress >1-2 dyn/cm(2) in vitro. Here, we show that lymphocyte slowing and transmigration in the skin is associated with microangiectasias, i.e., focal structural dilatations of microvessel segments. Microangiectasias are inducible within 4 days of the onset of inflammation and lead to a greater than 10-fold local reduction in wall shear stress. These findings support the hypothesis that a preparatory step to lymphocyte transmigration involves structural adaptations in the inflammatory microcirculation.
Secomb
Timothy W
TW
Department of Physiology, University of Arizona, Tucson, AZ 85724, USA.
Konerding
Moritz A
MA
West
Charles A
CA
Su
Mei
M
Young
Alan J
AJ
Mentzer
Steven J
SJ
D000818:Animals; D001696:Biomechanical Phenomena; D002448:Cell Adhesion; D002465:Cell Movement / Q000502:physiology*; D004730:Endothelium, Vascular / Q000473:pathology / Q000503:physiopathology; D006439:Hemodynamics; D066298:In Vitro Techniques; D007249:Inflammation / Q000097:blood / Q000473:pathology*; D008214:Lymphocytes / Q000473:pathology* / Q000502:physiology*; D008833:Microcirculation / Q000473:pathology / Q000503:physiopathology; D008855:Microscopy, Electron, Scanning; D018715:Microscopy, Video; D012756:Sheep