PLATELET ALTERATIONS IN RESPONSE TO REPETITIVE, SHORT-DURATION LAMINAR SHEAR STRESS

1987 ◽  
Author(s):  
J H Joist ◽  
J E Bauman ◽  
S P Sutera
Keyword(s):  
Shear Stress ◽  
Pulse Duration ◽  
Platelet Rich Plasma ◽  
Pulse Amplitude ◽  
Pulse Number ◽  
Dense Granule ◽  
Laminar Shear Stress ◽  
Ramp Function ◽  
Laminar Shear ◽  
Granule Release

We examined platelet aggregation (PAG = loss of single platelets), platelet dense granule release, and platelet injury (LDH loss) in normal human citrated platelet-rich plasma subjected to biologically more relevant repetitive, laminar shear stress of 25 and 50 dyn/cm2 in a computer-controlled cone-plate viscometer. Shear pulse duration (1-3 sec), shear pulse ramp function (rate of shear stress increase and decrease per pulse, 0.6-4 sec), number of shear pulses (1-20) and pauses between shear pulses (0-5 sec) were varied in different combinations to assess the effects of each variable on platelet alterations. Maximum PAG (92±8%) was observed with three 1 sec shear pulses, 0.6 sec ramp function and 1 sec between shear pause. PAG decreased with increasing ramp function, increasing number of shear pulses (>10), and increasing pause duration. Rapid platelet deaggregation (starting at 5 sec) was observed after a single 1 sec shear exposure. The rate of deaggregation decreased with increasing shear pulse number, increasing shear pulse amplitude, and increasing shear pulse duration. In contrast to PAG, dense granule release increased progressively with increasing shear pulse number, duration, and amplitude. No appreciable platelet injury (LDH loss) was observed under the conditions used. The findings indicate that massive reversible PAG can be induced by a single 1 sec shear pulse and that the extent of PAG with more prolonged, repetitive shear exposure is largely a function of platelet deaggregation rather than PAG. Thus, data previously reported from our laboratory and other investigators using prolonged (>5 sec) exposure of platelets to shear stress may require reevaluation.

Potentiation by red blood cells of shear-induced platelet aggregation: relative importance of chemical and physical mechanisms

Blood ◽  
1984 ◽  
Vol 64 (6) ◽  
pp. 1200-1206 ◽  
Author(s):  
RC Reimers ◽  
SP Sutera ◽  
JH Joist
Keyword(s):  
Shear Stress ◽  
Platelet Aggregation ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Platelet Rich Plasma ◽  
Adenine Nucleotides ◽  
Laminar Shear Stress ◽  
Platelet Surface ◽  
Surface Transport ◽  
Laminar Shear

Abstract Evidence has been reported to indicate that red blood cells (RBCs) may potentiate platelet adherence and platelet aggregation (PAG) in different flow systems in vitro as well as hemostatic platelet plug formation in response to vascular injury. In this study, we demonstrate that RBCs enhance PAG induced by well-defined, low-intensity, uniform, laminar shear stress. Potentiation by RBCs of shear-induced PAG was associated with appreciable loss of adenine nucleotides from 14C- adenine-labeled RBCs, the extent of which increased with increasing RBC concentration. The concentrations of RBC-derived ADP measured in the medium after shear, as determined by both high pressure liquid chromatography and the luciferin/luciferase system, were within the range of concentrations of ADP which may trigger PAG or potentiate PAG induced by low concentrations of other platelet agonists in the aggregometer. To assess the relative contribution of chemical (ADP) and physical (platelet surface transport) mechanisms in the RBC-mediated potentiation of shear-induced PAG, aliquots of citrated platelet-rich plasma (C-PRP) were exposed to shear stress in the presence of untreated RBCs or RBCs exposed to an antihemolytic concentration (5 mumol/L) of the membrane stabilizing agent, chlorpromazine (CPZ). Potentiation of shear-induced PAG in the RBC-CPZ system was significantly less than that in the untreated RBC system. However, CPZ- induced reduction of PAG potentiation was associated with an increase rather than a decrease in loss of adenine nucleotides from RBC. Furthermore, shear-induced PAG in C-PRP as well as ADP- and collagen- induced PAG in C-PRP in the aggregometer was significantly inhibited by 5 mumol/L CPZ, indicating that the observed reduced potentiation of shear-induced PAG by RBCs in the presence of CPZ was due to a direct inhibitory effect of the drug on platelets rather than a reduction of shear-induced liberation of ADP from RBCs. When aliquots of C-PRP were exposed to shear stress in the presence of RBCs completely depleted of ADP by fixation in 1% glutaraldehyde, potentiation of PAG was approximately half of that observed with intact RBCs. These findings indicate that both RBC-derived ADP and RBC-mediated platelet surface transport are involved in the potentiation by RBCs of PAG induced by laminar shear stress.

scholarly journals Potentiation by red blood cells of shear-induced platelet aggregation: relative importance of chemical and physical mechanisms

Blood ◽  
1984 ◽  
Vol 64 (6) ◽  
pp. 1200-1206 ◽  
Author(s):  
RC Reimers ◽  
SP Sutera ◽  
JH Joist
Keyword(s):  
Shear Stress ◽  
Platelet Aggregation ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Platelet Rich Plasma ◽  
Adenine Nucleotides ◽  
Laminar Shear Stress ◽  
Platelet Surface ◽  
Surface Transport ◽  
Laminar Shear

Evidence has been reported to indicate that red blood cells (RBCs) may potentiate platelet adherence and platelet aggregation (PAG) in different flow systems in vitro as well as hemostatic platelet plug formation in response to vascular injury. In this study, we demonstrate that RBCs enhance PAG induced by well-defined, low-intensity, uniform, laminar shear stress. Potentiation by RBCs of shear-induced PAG was associated with appreciable loss of adenine nucleotides from 14C- adenine-labeled RBCs, the extent of which increased with increasing RBC concentration. The concentrations of RBC-derived ADP measured in the medium after shear, as determined by both high pressure liquid chromatography and the luciferin/luciferase system, were within the range of concentrations of ADP which may trigger PAG or potentiate PAG induced by low concentrations of other platelet agonists in the aggregometer. To assess the relative contribution of chemical (ADP) and physical (platelet surface transport) mechanisms in the RBC-mediated potentiation of shear-induced PAG, aliquots of citrated platelet-rich plasma (C-PRP) were exposed to shear stress in the presence of untreated RBCs or RBCs exposed to an antihemolytic concentration (5 mumol/L) of the membrane stabilizing agent, chlorpromazine (CPZ). Potentiation of shear-induced PAG in the RBC-CPZ system was significantly less than that in the untreated RBC system. However, CPZ- induced reduction of PAG potentiation was associated with an increase rather than a decrease in loss of adenine nucleotides from RBC. Furthermore, shear-induced PAG in C-PRP as well as ADP- and collagen- induced PAG in C-PRP in the aggregometer was significantly inhibited by 5 mumol/L CPZ, indicating that the observed reduced potentiation of shear-induced PAG by RBCs in the presence of CPZ was due to a direct inhibitory effect of the drug on platelets rather than a reduction of shear-induced liberation of ADP from RBCs. When aliquots of C-PRP were exposed to shear stress in the presence of RBCs completely depleted of ADP by fixation in 1% glutaraldehyde, potentiation of PAG was approximately half of that observed with intact RBCs. These findings indicate that both RBC-derived ADP and RBC-mediated platelet surface transport are involved in the potentiation by RBCs of PAG induced by laminar shear stress.

Epigenetic histones modification and cardiovascular lineage programming in mouse embryonic stem cells exposed to laminar shear stress

2006 ◽  
Vol 45 (3) ◽  
pp. e56
Author(s):  
Barbara Illi ◽  
Alessandro Scopece ◽  
Simona Nanni ◽  
Antonella Farsetti ◽  
Liliana Morgante ◽  
...  
Keyword(s):  
Stem Cells ◽  
Shear Stress ◽  
Embryonic Stem Cells ◽  
Embryonic Stem ◽  
Mouse Embryonic Stem Cells ◽  
Laminar Shear Stress ◽  
Laminar Shear

scholarly journals Laminar shear stress upregulates endothelial Ca2+-activated K+ channels KCa2.3 and KCa3.1 via a Ca2+/calmodulin-dependent protein kinase kinase/Akt/p300 cascade

2013 ◽  
Vol 305 (4) ◽  
pp. H484-H493 ◽  
Author(s):  
Jun Takai ◽  
Alexandra Santu ◽  
Haifeng Zheng ◽  
Sang Don Koh ◽  
Masanori Ohta ◽  
...  
Keyword(s):  
Shear Stress ◽  
Transcriptional Activation ◽  
Static Condition ◽  
Fold Increase ◽  
Laminar Shear Stress ◽  
Human Coronary Artery ◽  
Intracellular Ca ◽  
Kinase Cascade ◽  
Dependent Protein ◽  
Laminar Shear

In endothelial cells (ECs), Ca2+-activated K+ channels KCa2.3 and KCa3.1 play a crucial role in the regulation of arterial tone via producing NO and endothelium-derived hyperpolarizing factors. Since a rise in intracellular Ca2+ levels and activation of p300 histone acetyltransferase are early EC responses to laminar shear stress (LS) for the transcriptional activation of genes, we examined the role of Ca2+/calmodulin-dependent kinase kinase (CaMKK), the most upstream element of a Ca2+/calmodulin-kinase cascade, and p300 in LS-dependent regulation of KCa2.3 and KCa3.1 in ECs. Exposure to LS (15 dyn/cm2) for 24 h markedly increased KCa2.3 and KCa3.1 mRNA expression in cultured human coronary artery ECs (3.2 ± 0.4 and 45 ± 10 fold increase, respectively; P < 0.05 vs. static condition; n = 8–30), whereas oscillatory shear (OS; ± 5 dyn/cm2 × 1 Hz) moderately increased KCa3.1 but did not affect KCa2.3. Expression of KCa2.1 and KCa2.2 was suppressed under both LS and OS conditions, whereas KCa1.1 was slightly elevated in LS and unchanged in OS. Inhibition of CaMKK attenuated LS-induced increases in the expression and channel activity of KCa2.3 and KCa3.1, and in phosphorylation of Akt (Ser473) and p300 (Ser1834). Inhibition of Akt abolished the upregulation of these channels by diminishing p300 phosphorylation. Consistently, disruption of the interaction of p300 with transcription factors eliminated the induction of these channels. Thus a CaMKK/Akt/p300 cascade plays an important role in LS-dependent induction of KCa2.3 and KCa3.1 expression, thereby regulating EC function and adaptation to hemodynamic changes.

scholarly journals Laminar Shear Stress Inhibits Endothelial Cell Metabolism via KLF2-Mediated Repression of PFKFB3

2015 ◽  
Vol 35 (1) ◽  
pp. 137-145 ◽  
Author(s):  
Anuradha Doddaballapur ◽  
Katharina M. Michalik ◽  
Yosif Manavski ◽  
Tina Lucas ◽  
Riekelt H. Houtkooper ◽  
...  
Keyword(s):  
Shear Stress ◽  
Endothelial Cell ◽  
Cell Metabolism ◽  
Laminar Shear Stress ◽  
Laminar Shear ◽  
Endothelial Cell Metabolism

Endothelial albumin permeability is shear dependent, time dependent, and reversible

1991 ◽  
Vol 260 (6) ◽  
pp. H1992-H1996 ◽  
Author(s):  
H. Jo ◽  
R. O. Dull ◽  
T. M. Hollis ◽  
J. M. Tarbell
Keyword(s):  
Shear Stress ◽  
Endothelial Cell ◽  
Fluorescein Isothiocyanate ◽  
Vascular Wall ◽  
Laminar Shear Stress ◽  
Aortic Endothelial Cells ◽  
Transendothelial Permeability ◽  
Steady Laminar Shear Stress ◽  
Laminar Shear

Altered permeability of vascular endothelium to macromolecules may play a role in vascular disease as well as vascular homeostasis. Because the shear stress of flowing blood on the vascular wall is known to influence many endothelial cell properties, an in vitro system to measure transendothelial permeability (Pe) to fluorescein isothiocyanate conjugated bovine serum albumin under defined physiological levels of steady laminar shear stress was developed. Bovine aortic endothelial cells grown on polycarbonate filters pretreated with gelatin and fibronectin constituted the model system. Onset of 1 dyn/cm2 shear stress resulted in a Pe rise from 5.1 +/- 1.3 x 10(-6) cm/s to 21.9 +/- 4.6 X 10(-6) cm/s at 60 min (n = 6); while 10 dyn/cm2 shear stress increased Pe from 4.8 +/- 1.5 X 10(-6) cm/s to 50.2 +/- 6.8 X 10(-6) cm/s at 30 min and 49.6 +/- 8.9 X 10(-6) cm/s at 60 (n = 9). Pe returned to preshear values within 120 and 60 min after removal of 1 and 10 dyn/cm2 shear stress, respectively. The data show that endothelial cell Pe in vitro is acutely sensitive to shear stress.

scholarly journals SENCR stabilizes vascular endothelial cell adherens junctions through interaction with CKAP4

2018 ◽  
Vol 116 (2) ◽  
pp. 546-555 ◽  
Author(s):  
Qing Lyu ◽  
Suowen Xu ◽  
Yuyan Lyu ◽  
Mihyun Choi ◽  
Christine K. Christie ◽  
...  
Keyword(s):  
Shear Stress ◽  
Endothelial Cell ◽  
Noncoding Rna ◽  
Rna Binding ◽  
Adherens Junctions ◽  
Vascular Endothelial Cell ◽  
Membrane Integrity ◽  
Laminar Shear Stress ◽  
Loss Of Function ◽  
Laminar Shear

SENCR is a human-specific, vascular cell-enriched long-noncoding RNA (lncRNA) that regulates vascular smooth muscle cell and endothelial cell (EC) phenotypes. The underlying mechanisms of action of SENCR in these and other cell types is unknown. Here, levels of SENCR RNA are shown to be elevated in several differentiated human EC lineages subjected to laminar shear stress. Increases in SENCR RNA are also observed in the laminar shear stress region of the adult aorta of humanized SENCR-expressing mice, but not in disturbed shear stress regions. SENCR loss-of-function studies disclose perturbations in EC membrane integrity resulting in increased EC permeability. Biotinylated RNA pull-down and mass spectrometry establish an abundant SENCR-binding protein, cytoskeletal-associated protein 4 (CKAP4); this ribonucleoprotein complex was further confirmed in an RNA immunoprecipitation experiment using an antibody to CKAP4. Structure–function studies demonstrate a noncanonical RNA-binding domain in CKAP4 that binds SENCR. Upon SENCR knockdown, increasing levels of CKAP4 protein are detected in the EC surface fraction. Furthermore, an interaction between CKAP4 and CDH5 is enhanced in SENCR-depleted EC. This heightened association appears to destabilize the CDH5/CTNND1 complex and augment CDH5 internalization, resulting in impaired adherens junctions. These findings support SENCR as a flow-responsive lncRNA that promotes EC adherens junction integrity through physical association with CKAP4, thereby stabilizing cell membrane-bound CDH5.

scholarly journals Endothelial Barrier Function is co-regulated at Vessel Bifurcations by Fluid Forces and Sphingosine-1-Phosphate

2020 ◽  
Author(s):  
Ehsan Akbari ◽  
Griffin B. Spychalski ◽  
Miles M. Menyhert ◽  
Kaushik K. Rangharajan ◽  
Shaurya Prakash ◽  
...  
Keyword(s):  
Shear Stress ◽  
Fluid Flow ◽  
Barrier Function ◽  
Endothelial Barrier ◽  
Laminar Shear Stress ◽  
Endothelial Barrier Function ◽  
Fluid Forces ◽  
Sphingosine 1 Phosphate ◽  
Laminar Shear ◽  
Vessel Bifurcations

AbstractSphingosine-1-phosphate (S1P) is a blood-borne bioactive lipid mediator of endothelial barrier function. Prior studies have implicated mechanical stimulation due to intravascular laminar shear stress in co-regulating S1P signaling in endothelial cells (ECs). Yet, vascular networks in vivo consist of vessel bifurcations, and this geometry produces hemodynamic forces that are distinct from laminar shear stress. However, the role of these forces at vessel bifurcations in regulating S1P-dependent endothelial barrier function is not known. In this study, we implemented a microfluidic platform that recapitulates the flow dynamics of vessel bifurcations with in situ quantification of the permeability of microvessel analogues. Co-application of S1P with impinging bifurcated fluid flow, which was characterized by approximately zero shear stress and 38 dyn cm-2 stagnation pressure at the vessel bifurcation point, promotes vessel stabilization. Similarly, co-treatment of carrier-free S1P with 3 dyn cm-2 laminar shear stress is also protective of endothelial barrier function. Moreover, it is shown that vessel stabilization due to laminar shear stress, but not bifurcated fluid flow, is dependent on S1P receptor 1 or 2 signaling. Collectively, these findings demonstrate the endothelium-protective function of fluid forces at vessel bifurcations and their involvement in coordinating S1P-dependent regulation of vessel permeability.

scholarly journals Primary cilia of human endothelial cells disassemble under laminar shear stress

2004 ◽  
Vol 164 (6) ◽  
pp. 811-817 ◽  
Author(s):  
Carlo Iomini ◽  
Karla Tejada ◽  
Wenjun Mo ◽  
Heikki Vaananen ◽  
Gianni Piperno
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Primary Cilia ◽  
Umbilical Vein ◽  
Intraflagellar Transport ◽  
Mechanical Stimuli ◽  
Laminar Shear Stress ◽  
Human Endothelial Cells ◽  
Umbilical Vein Endothelial Cells ◽  
Laminar Shear

We identified primary cilia and centrosomes in cultured human umbilical vein endothelial cells (HUVEC) by antibodies to acetyl-α-tubulin and capillary morphogenesis gene-1 product (CMG-1), a human homologue of the intraflagellar transport (IFT) protein IFT-71 in Chlamydomonas. CMG-1 was present in particles along primary cilia of HUVEC at interphase and around the oldest basal body/centriole at interphase and mitosis. To study the response of primary cilia and centrosomes to mechanical stimuli, we exposed cultured HUVEC to laminar shear stress (LSS). Under LSS, all primary cilia disassembled, and centrosomes were deprived of CMG-1. We conclude that the exposure to LSS ends the IFT in cultured endothelial cells.

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