Hemorheological aspects of the endothelium-plasma interface

Copley, Alfred L.

doi:10.1016/0026-2862(74)90094-6

Cited by 52 publications

(23 citation statements)

References 62 publications

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“…However, during perfusion of the frog mesentery with a Ringer's solution containing Evans blue, which has a high affinity for albumin, Chambers and Zweifach [18] observed "thin strands and sheets of a faintly colored blue, translucent material … sloughing off the inner surface of the capillary." About 20 years later, Copley [21,22] studied the endothelium-plasma interface and developed a concept ( Fig. 1) in which the endothelial surface is covered by a thin molecular layer and an immobile sheet of plasma.…”

Section: Introductionmentioning

confidence: 99%

“…For the rabbit arteries investigated, such measurements yielded values of glycocalyx thickness 654 Fig. 1 Structure of the endothelial surface and the blood flowing adjacent to it according to Copley [21]. A thin layer molecular layer is directly attached to the endothelial cell membrane, which Copley assumed to consist mainly of fibrin (endoendothelial fibrin film).…”

Section: Introductionmentioning

confidence: 99%

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The endothelial surface layer

Pries

Secomb

Gaehtgens

2000

Pflugers Arch - Eur J Physiol

767

708

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The endothelial lining of blood vessels presents a large surface area for exchange of materials between blood and tissues, and is critically involved in many other processes such as regulation of blood flow, inflammatory responses and blood coagulation. It has long been known that the luminal surface of the endothelium is lined with a glycocalyx, a layer of membrane-bound macromolecules which has been determined by electron microscopy to be several tens of nanometers thick. However, investigations in vivo have indicated the presence of a much thicker endothelial surface layer (ESL), with an estimated thickness ranging from 0.5 microm to over 1 microm, that restricts the flow of plasma and can exclude red blood cells and some macromolecular solutes. The evidence for the existence of the ESL, hypotheses about its composition and biophysical properties, its relevance to physiological processes, and its possible clinical implications are considered in this review.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The endothelial surface layer

Pries

Secomb

Gaehtgens

2000

Pflugers Arch - Eur J Physiol

767

708

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“…In view of its predominant polysaccharide constituents, Bennett termed it the “glycocalyx,” as derived from the Latin for “sweet husk.” In view of its labile nature and complement of proteins adsorbed from the blood stream, it has often been referred to as the endothelial surface layer . The function and molecular composition of the glycocalyx have long been viewed as a principal determinant of vascular homeostasis . Studies by electron microscopy have suggested that the fine structure of the glycocalyx consists of a network of glycoproteins on the order of 50–100 nm thick, with a characteristic spacing of 20 nm that accounts for the resistance to filtration of small molecules .…”

Section: Introductionmentioning

confidence: 99%

Shear‐Dependent Adhesion of Leukocytes and Lectins to the Endothelium and Concurrent Changes in Thickness of the Glycocalyx of Post‐Capillary Venules in the Low‐Flow State

Lipowsky

Lescanic

2013

Microcirculation

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Objectives To elucidate shear dependent effects of deformation of the endothelial glycocalyx on adhesion of circulating ligands in post-capillary venules, and delineate effect of matrix metalloproteases (MMPs). Methods Adhesion of leukocytes (WBCs) and lectin-coated fluorescently labeled microspheres (FLMs, 0.1 μm diameter), to endothelium (EC) of post-capillary venules in mesentery was examined during acute reductions in shear rates (γ̇, hemorrhagic hypotension). Adhesion was examined with or without superfusion with 0.5 μM doxycycline to inhibit MMPs. Thickness of the glycocalyx was measured by exclusion of fluorescent 70 kDa dextran from the EC surface. Results During superfusion with Ringers, rapid reductions in γ̇ resulted in a significant rise in WBC adhesion and a two-fold rise in microsphere adhesion. With addition of doxycycline WBC and FLM adhesion increased two-fold under high and low flow conditions. FLM adhesion was invariant with γ̇ throughout the network in the normal (high) flow state. With reductions in γ̇, thickness of the glycocalyx increased significantly, with or without doxycycline. Conclusions The concurrent increase in WBC and FLM adhesion with increased thickness of the glycocalyx during reductions in shear suggests that glycocalyx core proteins recoil from their deformed steady state configuration, which increases exposure of binding sites for circulating ligands.

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“…Flowing RBCs may interact with macromolecules on the endothelial surface of microvessels [46], and the RBCs may temporarily stick on the surface [47]. The shear stress may change the interaction through the alteration of spatial organization of the macromolecules on the endothelial surface [48].…”

Section: Blood Flow Structuring Under the In Vitro Conditionsmentioning

confidence: 99%

Blood Flow Structure Related to Red Cell Flow: Determinant of Blood Fluidity in Narrow Microvessels

Mchedlishvili

Maeda²

2001

Jpn.J.Physiol

112

104

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Blood advancing in living capillaries (5 to 10 m in diameter) and in the adjoining arterioles and venules (10 to 25 m in diameter) itself represents a specific substance hardly comparable with fluids in a usual understanding of this term. Its greatest part comprises the deformed red blood cells (RBCs) whose size is similar to luminal diameters of the microvessels. The RBCs (comprising great majority of the forming elements in microvessels) are disposed in the normal flow not chaotically, but in a certain order that was identified therefore as "blood flow structure (or structuring) in microvessels" [1][2][3].The specific regime of the RBCs flow in blood vessels changes from larger to smaller luminal diameters. Thus in vessels larger than 0.2 mm, the blood flow can be treated as a homogenous suspension with little error. By contrast, in arterioles or venules smaller than 25 m, and especially in capillaries (whose diameters are smaller than 8 m in humans), the RBCs are not uniformly dispersed, especially because of the presence of a parietal plasma layer containing no cells; thus the blood flow is specifically structured (Fig. 1). Disorders of this kind inevitably lead to the disturbance of normal blood rheological properties in the microvessels.Japanese Journal of Physiology Vol. 51, No. 1, 2001 19Japanese Journal of Physiology, 51, 19-30, 2001 Key words: RBC axial flow, parietal plasma layer, RBC aggregation, RBC deformation, plasma viscosity. Abstract:The review article deals with phenomena of the blood flow structure (structuring) in narrow microvessels-capillaries and the adjacent arterioles and venules. It is particularly focused on the flow behavior of red blood cells (RBCs), namely, on their specific arrangements of mutual interaction while forming definite patterns of self-organized microvascular flow. The principal features of the blood flow structure in microvessels, including capillaries, include axial RBC flow and parietal plasma layer, velocity profile in larger microvessels, plug (or bolus) flow in narrow capillaries, and deformation and specific behavior of the RBCs in the flow. The actual blood flow structuring in microvessels seems to be a most significant factor in the development of pathological conditions, including arterial hypertension, brain and cardiac infarctions, inflammation, and many others. The blood flow structuring might become a basic concept in determining the blood rheological properties and disorders in the narrow microvessels. No solid theoretical (biorheological) basis of the blood flow structuring in microvessel has been found, but in the future it might become a foundation for a better understanding of the mechanisms of these properties under normal and pathological conditions in the narrowest microvessels 5 to 25 m large. It is also a topic for further biorheological research directed to find the background of actual physiopathological phenomena in the microcirculation.

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Hemorheological aspects of the endothelium-plasma interface

Cited by 52 publications

References 62 publications

The endothelial surface layer

The endothelial surface layer

Shear‐Dependent Adhesion of Leukocytes and Lectins to the Endothelium and Concurrent Changes in Thickness of the Glycocalyx of Post‐Capillary Venules in the Low‐Flow State

Blood Flow Structure Related to Red Cell Flow: Determinant of Blood Fluidity in Narrow Microvessels

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