Red Blood Cell Aggregation and Microcirculation in Rat Cremaster Muscle

Vicaut, Éric; Hou, Xin; Decuypère, L.; Taccoen, A.; Duvelleroy, M

doi:10.1159/000178201

Cited by 42 publications

(29 citation statements)

References 18 publications

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“…This phenomenon was known since long ago, but the relationship between the RBCs aggregation (as cause) and the increase of resistance disturbing the flow (as result) in microvessels was difficult to prove convincingly because some inevitable factors, such as the pressure gradient and/or the microvascular diameter changes, could always be involved in the living microvascular networks. The effect of the RBCs aggregation on blood flow was largely examined by infusing macromolecules, preferably dextran with high molecular weight, into isolated organs [60][61][62] and in patients with serum hyperviscosity syndrome [63,64]. Under these conditions it was difficult to prove whether the increased flow resistance was due to the RBCs aggregation itself or to the increased plasma viscosity.…”

Section: Rbcs Aggregation As a Factor Inevitably Disturbing Blood Flomentioning

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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Section: Rbcs Aggregation As a Factor Inevitably Disturbing Blood Flomentioning

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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“…Mchedlishvili et al (19) found that administration of Dextran 500 reduced the FCD in the rabbit cerebral cortex dramatically, from ϳ90% to ϳ10%. Vicaut et al (32,33) also found substantial reductions (Ͼ30%) in FCD in rat hearts and cremaster muscle after the infusion of Dextran 480. Both studies indicated that red blood cell aggregation can reduce FCD to a level that would increase the diffusion distance for nutrients and waste products and reduce available surface area for exchange of fluid and solutes.…”

mentioning

confidence: 90%

Effect of erythrocyte aggregation at normal human levels on functional capillary density in rat spinotrapezius muscle

Kim

Popel²,

Intaglietta

et al. 2006

American Journal of Physiology-Heart and Circulatory Physiology

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Previous studies have shown that functional capillary density (FCD) is substantially reduced by erythrocyte aggregation. However, only supranormal levels of aggregability were studied. To investigate the effect of erythrocyte aggregability at the level seen in healthy humans, the FCD of selected capillary fields in rat spinotrapezius muscle was determined with high-speed video microscopy under normal (nonaggregating) conditions and after induction of erythrocyte aggregation with Dextran 500 (200 mg/kg). To examine shear rate dependence, the effect was studied both at normal and reduced arterial pressures (50 and 25 mmHg), the latter achieved by short periods of hemorrhage. In a separate study, volume flow was determined in arterioles (52.1 +/- 3.7 microm) under the same conditions. Before Dextran 500 infusion, FCD fell to 91% and 76% of control values, respectively, when arterial pressure was reduced to 50 and 25 mmHg. After Dextran 500 infusion, FCD was 96% at normal arterial pressure and fell to 79% and 37% of normal control values at 50 and 25 mmHg. All FCD values were significantly lower after dextran infusion. FCD reduction after lowering arterial pressure or dextran infusion appeared to be due to plasma skimming rather than capillary plugging. Reduction of FCD by dextran at reduced pressure was compensated by increased red blood cell flux in capillaries with red blood cell flow. We conclude that the level of aggregability seen in healthy humans is an important determinant of FCD only at reduced arterial pressure.

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“…In vivo experiments using glutaraidehvde (or formaldehyde)-treated erythrocytes have shown the increased flow resis tance in the microvascular network [10][11][12], On the other hand, the physiological influence of erythrocyte aggrega tion on systemic circulation has also been examined in vivo by injecting various macromolecules such as dextrans. However, it is controversial whether the increased viscosity and thus the increased flow resistance is due to the erythrocyte aggregation itself or to the increased plas ma viscosity [13][14][15][16][17],…”

Section: Introductionmentioning

confidence: 99%

Flow Behavior of Erythrocytes in Microvessels and Glass Capillaries: Effects of Erythrocyte Deformation and Erythrocyte Aggregation

Suzuki

Tateishi²,

Soutani³

et al. 1996

Int J Microcirc

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Flow behavior of erythrocytes in microvessels and glass capillaries with an inner diameter of 10-50 µm was compared in relation to erythrocyte deformation and erythrocyte aggregation. This study was focused on the formation of a marginal cell-free layer, and the thickness was determined using an image processor. Human erythrocytes were perfused through a part of microvascular networks isolated from rabbit mesentery and through glass capillaries. Erythrocyte deformability was modified by treating erythrocytes with diamide, diazene-dicarboxylic acid bis[N, N-dimethylamide], and erythrocyte aggregation was accelerated by adding dextran (with a molecular weight of 70,400) to the perfusion medium. The thickness of the cell-free layer increased with an increase of the inner diameter of flow channel, with lowering the hematocrit, and with increasing the flow velocity of erythrocytes, in both microvessels and glass capillaries. Furthermore, the thickness of cell-free layer decreased with decreasing erythrocyte deformability, while it increased with accelerating erythrocyte aggregation. However, the alteration of the cell-free layer in response to the changes of these hemorheological conditions was more sensitive in microvessels than in glass capillaries. The present study concludes that flow behavior of erythrocytes in microvessels is qualitatively similar to, but quantitatively different from those in glass capillaries, as far as evaluated by the change of the thickness of the marginal cell-free layer.

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Red Blood Cell Aggregation and Microcirculation in Rat Cremaster Muscle

Cited by 42 publications

References 18 publications

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

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

Effect of erythrocyte aggregation at normal human levels on functional capillary density in rat spinotrapezius muscle

Flow Behavior of Erythrocytes in Microvessels and Glass Capillaries: Effects of Erythrocyte Deformation and Erythrocyte Aggregation

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