Neutrophils Emigrate from Venules by a Transendothelial Cell Pathway in Response to FMLP

摘要: Circulating leukocytes are thought to extravasate from venules through open interendothelial junctions. To test this paradigm, we injected N-formyl-methionyl-leucyl-phenylalanine (FMLP) intradermally in guinea pigs, harvesting tissue at 5–60 min. At FMLP-injected sites, venular endothelium developed increased surface wrinkling and variation thickness. Marginating neutrophils formed contacts with endothelial cells other neutrophils, sometimes forming chains of linked leukocytes. Adherent projected cytoplasmic processes into the underlying endothelium, especially points thinning. determine pathway by which transmigrated prepared 27 sets serial electron microscopic sections. Eleven these encompassed their entirety openings individual traversed endothelium; 10 11 sets, followed an entirely transendothelial cell course unrelated junctions, findings that were confirmed computer-assisted three-dimensional reconstructions. Having crossed often paused before crossing basal lamina pericytes they also commonly a transcellular pathway. Thus, response FMLP, emigrated cutaneous route both pericytes. It remains be determined whether results can extended inflammatory or stimuli vascular beds.