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Angiopoietin‐1 modifies multiple microvessel permeability coefficients in non‐inflamed vessels
Author(s) -
Salmon Andrew,
Harper Steven,
Bates David
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.926.2
Subject(s) - microvessel , microcirculation , chemistry , permeability (electromagnetism) , vascular permeability , angiopoietin 2 , angiogenesis , endocrinology , medicine , biology , vascular endothelial growth factor , biochemistry , membrane , vegf receptors
Angiopoietin‐1 (Ang1) is widely expressed by pericytes and induces constitutive phosphorylation of the endothelial cell receptor Tie2. Ang1 reduces neutrophil adhesion and solute flux following inflammatory stimulation. We examined the hitherto untested hypothesis that Ang1 modifies permeability coefficients in non‐inflamed microvessels. Continuous microvessel hydraulic conductivity ( L P : x10 7 cm.s −1 .cmH 2 O −1 ) and reflection coefficient (σ) were measured in frog mesenteric microvessels with the Landis‐Michel assay. Ang1 (200 ng.ml −1 ) caused a significant rise in σ (vehicle: 0.78±0.03; Ang1: 0.91±0.03; p<0.05, paired t‐test (n=10)) and a significant reduction in L P (vehicle: 2.0±0.9; Ang1: 1.2±0.9; p<0.05, Wilcoxon (n=11)). Fenestrated microvessel L P ‐area product ( L P A : nl.min −1 .mmHg −1 ), measured in isolated rat glomeruli with an oncometric assay, also reduced significantly in response to Ang1 (vehicle: 1.0±0.1 (n=31); Ang1: 0.8±0.1(n=30); p<0.05, unpaired t‐test). Ang1 may induce a plethora of changes in different microvessels that alter resistance to water and albumin movement, or may modify a determinant of microvascular permeability coefficients that is common to both continuous and fenestrated microvessels.