ABSTRACT
Systemic dissemination of microbes is critical for progression of many infectious diseases and is associated with most mortality due to bacterial infection. The physical mechanisms mediating a key dissemination step, bacterial association with vascular endothelia in blood vessels, remain unknown. Here, we show that endothelial interactions of the Lyme disease spirochete Borrelia burgdorferi under physiological shear stress mechanistically resemble selectin-dependent leukocyte rolling. Specifically, these interactions are mediated by transfer of mechanical load along a series of adhesion complexes and are stabilized by tethers and catch bond properties of the bacterial adhesin BBK32. Furthermore, we found that the forces imposed on adhesive bonds under flow may be small enough to permit active migration driven by bacterial flagellar motors. These findings provide insight into the biomechanics of bacterial-vascular interactions and demonstrate that disseminating bacteria and circulating host immune cells share widely conserved mechanisms for interacting with endothelia under physiological shear stress.
Subject(s)
Blood Vessels/microbiology , Blood Vessels/pathology , Borrelia burgdorferi/physiology , Host-Pathogen Interactions , Bacterial Adhesion , Bacterial Proteins/metabolism , Biomechanical Phenomena , Endothelial Cells/microbiology , Endothelial Cells/pathology , Humans , Leukocyte Rolling , Models, Biological , Multiprotein Complexes/metabolism , Rotation , Stress, Mechanical , Torque , Venules/pathology , Venules/virologyABSTRACT
Microvenular hemangioma (MVH) is an uncommon benign vascular neoplasm that usually occurs as a solitary asymptomatic red or purple papule, nodule, or plaque with a predilection for the upper extremities. Patients with more than 1 lesion, that is, multiple MVHs, are extremely rare. We describe the clinicopathologic features of 4 Chinese patients who had a rapidly progressive abrupt onset of numerous MVHs numbering in the tens to hundreds. Clinically, the correct diagnosis of MVH could not be made in any of our patients; however, histologic examination revealed the characteristic features of MVH. Immunohistochemical stains were performed in all cases and showed the vessel lining cells to be positive for CD34, CD31, and factor VIII-related antigen. Polymerase chain reaction for human herpesvirus-8 was negative in all cases. The differential diagnosis and review of the literature of patients with multiple MVHs are presented.
