Pathways of macromolecular extravasation across microvascular endothelium in response to VPF/VEGF and other vasoactive mediators.
Microcirculation
; 6(1): 23-44, 1999 Mar.
Article
em En
| MEDLINE
| ID: mdl-10100187
ABSTRACT
OBJECTIVE:
The goal of these studies was to define the anatomic pathways by which circulating macromolecules extravasate from the hyperpermeable microvessels that supply tumors and from normal venules that have been rendered hyperpermeable by vasoactive mediators.METHODS:
Extravasation pathways of circulating macromolecular tracers were followed by several morphological techniques light and fluorescence microscopy, transmission electron microscopy of routine as well as ultrathin and serial sections, computer-assisted three-dimensional reconstructions, and morphometry. RESULTS ANDDISCUSSION:
Macromolecules extravasated across tumor microvessels or across normal venules rendered hyperpermeable by VPF/VEGF, histamine, or serotonin by three primary pathways 1) Vesiculo-vacuolar organelles (VVOs), clusters of cytoplasmic vesicles and vacuoles that span endothelial cytoplasm from lumen to ablumen; 2) trans-endothelial cell (EC), pores, and 3) fenestrae. We also present data concerning the structure and function of VVOs as well as evidence that VVOs form as the result of linking together and fusion of caveolae-sized unit vesicles. Under suitable conditions VVOs also afforded a pathway for macromolecular transport in the reverse direction, i.e., from vascular ablumen to lumen. Finally, in addition to opening VVOs to the passage of macromolecules, mediators such as VPF/VEGF may also induce structural rearrangements of VVOs, transforming them into trans-EC pores or fenestrae.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Permeabilidade Capilar
/
Endotélio Vascular
/
Fatores de Crescimento Endotelial
/
Linfocinas
Limite:
Animals
/
Humans
Idioma:
En
Revista:
Microcirculation
Assunto da revista:
ANGIOLOGIA
Ano de publicação:
1999
Tipo de documento:
Article
País de afiliação:
Estados Unidos
País de publicação:
EEUU
/
ESTADOS UNIDOS
/
ESTADOS UNIDOS DA AMERICA
/
EUA
/
UNITED STATES
/
UNITED STATES OF AMERICA
/
US
/
USA