Effect of glycocalyx on shear-dependent albumin uptake in endothelial cells

Ueda, Akinori; Shimomura, Masaki; Ikeda, Mariko; Yamaguchi, Ryuhei; Tanishita, Kazuo

doi:10.1152/ajpheart.00808.2003

Cited by 72 publications

(64 citation statements)

References 39 publications

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“…Accordingly, an albumin-containing perfusate should ‘hook’ into this structure, transmitting shear stress to the vessel wall, while artificial colloids like HES, figuratively speaking, brush only against the top of the glycocalyx molecules [38]. Such a difference is reflected by the similarity in intravascular distribution spaces of HES and red blood cells in vivo, as opposed to those tracers binding to albumin [39, 40]. This interpretation is also in line with our previous work concerning the barrier function of the EG [4, 8, 17], which is also overproportionally enhanced by albumin versus HES [8].…”

Section: Discussionmentioning

confidence: 99%

The Endothelial Glycocalyx Prefers Albumin for Evoking Shear Stress-Induced, Nitric Oxide-Mediated Coronary Dilatation

Jacob¹,

Rehm²,

Loetsch³

et al. 2007

J Vasc Res

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Background: Shear stress induces coronary dilatation via production of nitric oxide (NO). This should involve the endothelial glycocalyx (EG). A greater effect was expected of albumin versus hydroxyethyl starch (HES) perfusion, because albumin seals coronary leaks more effectively than HES in an EG-dependent way. Methods: Isolated hearts (guinea pigs) were perfused at constant pressure with Krebs-Henseleit buffer augmented with 1/3 volume 5% human albumin or 6% HES (200/0.5 or 450/0.7). Coronary flow was also determined after EG digestion (heparinase) and with nitro-L-arginine (NO-L-Ag). Results: Coronary flow (9.50 ± 1.09, 5.10 ± 0.49, 4.87 ± 1.19 and 4.15 ± 0.09 ml/min/g for ‘albumin’, ‘HES 200’, ‘HES 450’ and ‘control’, respectively, n = 5–6) did not correlate with perfusate viscosity (0.83, 1.02, 1.24 and 0.77 cP, respectively). NO-L-Ag and heparinase diminished dilatation by albumin, but not additively. Alone NO-L-Ag suppressed coronary flow during infusion of HES 450. Electron microscopy revealed a coronary EG of 300 nm, reduced to 20 nm after heparinase. Cultured endothelial cells possessed an EG of 20 nm to begin with. Conclusions: Albumin induces greater endothelial shear stress than HES, despite lower viscosity, provided the EG contains negative groups. HES 450 causes some NO-mediated dilatation via even a rudimentary EG. Cultured endothelial cells express only a rudimentary glycocalyx, limiting their usefulness as a model system.

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Section: Discussionmentioning

confidence: 99%

The Endothelial Glycocalyx Prefers Albumin for Evoking Shear Stress-Induced, Nitric Oxide-Mediated Coronary Dilatation

Jacob¹,

Rehm²,

Loetsch³

et al. 2007

J Vasc Res

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“…Vink & Duling (2000) demonstrated that, for anionic molecules, in addition to size, the electric charge has a profound effect on the penetration rate into the EGL. Using cultured endothelial cells, Ueda et al (2004) showed that the albumin uptake for the endothelial cells with a neutralized (no charge) EGL was almost twice that of cells with charged EGL.…”

Section: Introductionmentioning

confidence: 99%

Effects of electric charge on osmotic flow across periodically arranged circular cylinders

2010

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An electrostatic model is developed for osmotic flow across a layer consisting of identical circular cylinders with a fixed surface charge, aligned parallel to each other so as to form an ordered hexagonal arrangement. The expression of the osmotic reflection coefficient is derived for spherical solutes with a fixed surface charge suspended in an electrolyte, based on low-Reynolds-number hydrodynamics and a continuum, point-charge description of the electric double layers. The repulsive electrostatic interaction between the surface charges with the same sign on the solute and the cylinders is shown to increase the exclusion region of solute from the cylinder surface, which enhances the osmotic flow. Applying the present model to the study of osmotic flow across the endothelial surface glycocalyx of capillary walls has revealed that this electrostatic model could account well for the reflection coefficients measured for charged macromolecules, such as albumin, in the physiological range of charge density and ion concentration.Key words: biomedical flows, biological fluid dynamics, low-Reynolds-number flows IntroductionOsmotic flow is generated between solutions of different concentrations that are separated by a porous membrane. When only solvent can enter the pores and the solutes are impermeable, a net volume flux of the solvent, referred to as the osmotic flow, is realized. If the solutes are only partially excluded from the membrane, then an osmotic reflection coefficient, σ v , must be introduced so as to express the solvent flux across the leaky membrane. In this case, the thermodynamic principles yield the following expression for the solvent flux J v per unit cross-sectional area when a hydrostatic pressure difference ( p ∞ ) and osmotic pressure difference ( π ∞ ) are applied across the membranewhere L p is the hydraulic permeability and ∞ denotes the bulk solution conditions on both sides of the membrane. The accompanying expression for the solute flux J s is

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“…Controversy exists also with respect to the dimensions of the glycocalyx on cultured endothelial cells. Findings range from Ϸ40 nm 19 to 2000 nm. 20 The findings of Potter and Damiano even suggest that cultured human umbilical vein endothelial cells (HUVECs) may be devoid of a glycocalyx.…”

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confidence: 99%

The Glycocalyx of the Human Umbilical Vein Endothelial Cell

Chappell¹,

Jacob²,

Paul³

et al. 2009

Circulation Research

191

109

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Abstract-Potter and Damiano recently assessed the hydrodynamic dimensions of the endothelial glycocalyx in vivo (mouse cremaster muscle venules) and in vitro (human umbilical vein and bovine aorta endothelium cultured in perfused microchannels) using fluorescent microparticle image velocimetry (Circ Res. 2008;102:770 -776). Great discrepancy was observed, the glycocalyx presenting a zone of interaction extending Ϸ0.52 m into the vessel lumen in vivo, but only 0.02 to 0.03 m from cultured cells. In an accompanying editorial, Barakat cautioned that the difference in hydrodynamic interaction did not allow one to conclude that the cultured cells totally lack a physical cell surface layer capable of mechanotransduction (Circ Res. 2008;102:747-748 and of endothelial cells grown in culture in perfused microchannels by means of fluorescent microparticle image velocimetry. 1 A great discrepancy was observed between the 2 settings, the glycocalyx presenting a zone of interaction extending Ϸ0.52 m into the vessel lumen in vivo, but only 0.02 to 0.03 m from cultured cells. As pointed out in an accompanying editorial by Barakat, this very intriguing difference in apparent thickness of the glycocalyx does not allow one to conclude that the cultured cells totally lack a cell surface layer. 2 In fact, an appeal is made for some form of direct visualization of the glycocalyx. The studies of Potter and Damiano also do not address the issue of whether there are differences in the molecular thickness or composition of the glycocalyx between in vivo and in vitro endothelial cells. 2 Based on their results, Potter and Damiano caution against inferences made from in vitro studies in the areas of microvascular permeability, inflammation, mechanotransduction, and atherosclerosis, if results from such studies depend on the integrity of the endothelial cell surface chemistry. 2 However, whether the glycocalyx of human endothelial cells might show similar discrepancy between the in vivo and in vitro setting remained to be shown.A healthy vascular endothelium is coated by a variety of transmembrane-and membrane-attached molecules such as syndecans and glypicans, both carrying heparan sulfate and chondroitin sulfate side chains, which together constitute the scaffold of the endothelial glycocalyx. 3,4 The glycocalyx is also made up of many functionally important molecular components such as cell adhesion molecules, eg, integrins and selectins, 3 inflammatory regulators and adsorbed components, eg, of the coagulation system. 5,6 Interaction with plasma colloids conveys mechanosensitivity to the endothelium, contributing to the regulation of vascular tone. 7 Initially, the endothelial glycocalyx was believed to be an insignificant structure with a thickness of only a few tens of Original

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Effect of glycocalyx on shear-dependent albumin uptake in endothelial cells

Cited by 72 publications

References 39 publications

The Endothelial Glycocalyx Prefers Albumin for Evoking Shear Stress-Induced, Nitric Oxide-Mediated Coronary Dilatation

The Endothelial Glycocalyx Prefers Albumin for Evoking Shear Stress-Induced, Nitric Oxide-Mediated Coronary Dilatation

Effects of electric charge on osmotic flow across periodically arranged circular cylinders

The Glycocalyx of the Human Umbilical Vein Endothelial Cell

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