Quantitative fluorescence microscopy on single capillaries: alpha-lactalbumin transport

Huxley, Virginia H.; Curry, F. E.; Adamson, Roger H.

doi:10.1152/ajpheart.1987.252.1.h188

Cited by 125 publications

(141 citation statements)

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“…A pertinent aspect of the model is the boundary condition describing movement of INS-647 from the plasma to the interstitial space. We described the boundary behavior of INS-647 with equations describing either diffusion (25), fluid-phase transport (26), or Michaelis-Menten kinetics. We then solved the diffusion equation with the different boundary conditions to generate models that described these potential mechanisms of INS-647 transport.…”

Section: Resultsmentioning

confidence: 99%

Insulin exits skeletal muscle capillaries by fluid-phase transport

Williams¹,

Valenzuela²,

Kahl³

et al. 2018

Journal of Clinical Investigation

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Section: Resultsmentioning

confidence: 99%

Insulin exits skeletal muscle capillaries by fluid-phase transport

Williams¹,

Valenzuela²,

Kahl³

et al. 2018

Journal of Clinical Investigation

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“…Huxley et al demonstrated that when the solute permeability coefficient (P s ) is plotted against pressure, it is apparent that the transcapillary solute flux increases as capillary hydrostatic pressure is increased, even though the solute permeability was unchanged. Extrapolation of this regression line shows that a significant flux occurs when the net filtration pressure is zero, indicating that both diffusive and solvent drag (convective) forces determine the flux of solute across vessel wall [32]. This convective flux may be the key to understanding changes in permeability in diabetes.…”

Section: Measurement Of Microvascular Permeability In Diabetes Mellitusmentioning

confidence: 96%

A Role for the Endothelial Glycocalyx in Regulating Microvascular Permeability in Diabetes Mellitus

Perrin

Harper

Bates

2007

Cell Biochem Biophys

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Diabetic angiopathy is a major cause of morbidity and mortality in diabetes mellitus. Endothelial dysfunction and associated alterations in blood flow, pressure and permeability are widely accepted phenomena in the diabetic milieu and are understood to lead to microangiopathy. Despite the clinical importance of diabetic microangiopathy, the mechanisms of pathogenesis remain elusive. In particular, much is yet to be understood about the nature of the putative increased permeability with respect to diabetes. Microvessel permeability is intrinsically difficult to measure and a surrogate (solute or solvent flux) is usually reported, the measurement of which is hampered by haemodynamic factors, such as flow rate, hydrostatic pressure gradient, solute concentration and surface area available for exchange. Very few studies describing the measurement of permeability with respect to diabetes have controlled for all these factors. As a result, the nature of the increased microvessel permeability in diabetes mellitus and indeed its causes are poorly understood. Recent studies have shown that hyperglycaemia can alter the glycocalyx structure, and parallel findings have shown that the apparent increase in permeability demonstrated in hyperglycaemia may be due to an increase in the permeability of the vessels to water, and not an increase in protein permeability, an effect attributable to altered glycocalyx. This review focuses on the current understanding of microvascular permeability in terms of the endothelial glycocalyxfibre-matrix theory, those methods used to determine permeability in the context of diabetes, and the more recent developments in our understanding of elevated microvascular permeability in the diabetic circulation.

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“…A detailed description of the methods and assumptions used to measure fluorescent solute flux (J s) crossing the walls of single perfused vessels and to calculate apparent permeability coefficients [solute permeability (Ps)] has been previously published (9,10,19). Ps includes both diffusive and convective components of Js between blood and tissue.…”

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confidence: 99%

Albumin modulates S1P delivery from red blood cells in perfused microvessels: mechanism of the protein effect

Adamson

Clark

Radeva

et al. 2014

American Journal of Physiology-Heart and Circulatory Physiology

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Adamson RH, Clark JF, Radeva M, Kheirolomoom A, Ferrara KW, Curry FE. Albumin modulates S1P delivery from red blood cells in perfused microvessels: mechanism of the protein effect. Am J Physiol Heart Circ Physiol 306: H1011-H1017, 2014. First published February 15, 2014 doi:10.1152/ajpheart.00829.2013.-Removal of plasma proteins from perfusates increases vascular permeability. The common interpretation of the action of albumin is that it forms part of the permeability barrier by electrostatic binding to the endothelial glycocalyx. We tested the alternate hypothesis that removal of perfusate albumin in rat venular microvessels decreased the availability of sphingosine-1-phosphate (S1P), which is normally carried in plasma bound to albumin and lipoproteins and is required to maintain stable baseline endothelial barriers (Am J Physiol Heart Circ Physiol 303: H825-H834, 2012). Red blood cells (RBCs) are a primary source of S1P in the normal circulation. We compared apparent albumin permeability coefficients [solute permeability (P s)] measured using perfusates containing albumin (10 mg/ml, control) and conditioned by 20-min exposure to rat RBCs with P s when test perfusates were in RBC-conditioned protein-free Ringer solution. The control perfusate S1P concentration (439 Ϯ 46 nM) was near the normal plasma value at 37°C and established a stable baseline P s (0.9 Ϯ 0.4 ϫ 10 Ϫ6 cm/s). Ringer solution perfusate contained 52 Ϯ 8 nM S1P and increased P s more than 10-fold (16.1 Ϯ 3.9 ϫ 10 Ϫ6 cm/s). Consistent with albumin-dependent transport of S1P from RBCs, S1P concentrations in RBC-conditioned solutions decreased as albumin concentration, hematocrit, and temperature decreased. Protein-free Ringer solution perfusates that used liposomes instead of RBCs as flow markers failed to maintain normal permeability, reproducing the "albumin effect" in these mammalian microvessels. We conclude that the albumin effect depends on the action of albumin to facilitate the release and transport of S1P from RBCs that normally provide a significant amount of S1P to the endothelium. albumin; endothelium; permeability; sphingosine-1-phosphate; vascular WE AND OTHERS have demonstrated that red blood cells (RBCs) are an important source of the plasma phospholipid sphingosine-1-phosphate (S1P), which acts continuously to maintain normal vascular permeability (7,9,24,34,43,50). The aim of the present experiments was to investigate the mechanisms that control the delivery of S1P from RBCs to the endothelium in intact microvessels. Our specific focus was the action of albumin as a carrier of S1P and as a modulator of vascular permeability. It has been known for many decades that the presence of albumin in vascular perfusates stabilizes the endothelial barrier (13,14,18,23,25,28,46). Removal of plasma proteins from perfusates increases vascular permeability and results in loss of the endothelial glycocalyx (11,29,32,33).The common interpretation of the action of albumin is that it forms part of the permeability barrier by electrostatic bindin...

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Quantitative fluorescence microscopy on single capillaries: alpha-lactalbumin transport

Cited by 125 publications

References 0 publications

Insulin exits skeletal muscle capillaries by fluid-phase transport

Insulin exits skeletal muscle capillaries by fluid-phase transport

A Role for the Endothelial Glycocalyx in Regulating Microvascular Permeability in Diabetes Mellitus

Albumin modulates S1P delivery from red blood cells in perfused microvessels: mechanism of the protein effect

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