Effects of Ionic and Nonionic Contrast Media on Endothelium and on Arterial Thrombus Formation

1996 ◽  
Vol 37 (3P2) ◽  
pp. 954-961 ◽  
Author(s):  
R. M. Barstad ◽  
M. S. Buchmann ◽  
M. J. A. G. Hamers ◽  
L. Örning ◽  
U. Ørvim ◽  
...  

Background: The aims of the present study were to investigate whether ionic and nonionic contrast media (CM) affect: 1) the procoagulant and fibrinolytic activities of cultured human vessel endothelium; and 2) early events of tissue-factor-induced arterial thrombus formation under conditions which may follow a percutaneous transluminal coronary angioplasty (PTCA) procedure. The following 3 CM were studied: iohexol (nonionic monomer, Omnipaque); iodixanol (nonionic dimer, Visipaque); and ioxaglate (ionic dimer, Hexabrix). Saline (0.9%) and glucose (40 vol%) were used as control. Methods and Results: Exposing endothelium to 40 vol% CM for 10 min did not affect the selected parameters of cellular procoagulant (tissue factor), anticoagulant (thrombomodulin), fibrinolytic (tissue plasminogen activator) or antifibrinolytic (plasminogen activator inhibitor-1) activity or antigen. However, ioxaglate had a profound impact on the cell morphology, which was noted already after one minute of exposure. The cells contracted and rounded, exposing large areas of extracellular matrix. Iohexol showed this phenomenon to a considerably lesser extent, whereas iodixanol induced a slight swelling of the cells without detectable exposure of extracellular matrix. The effect of the respective CM on tissue-factor-driven thrombus formation at an arterial shear rate of 2600 s−1 was studied in an ex vivo parallel-plate perfusion chamber device. In this model, human native blood was passed over a tissue factor/phospholipid-rich surface following 30 s exposure to 100% CM. The CM was washed out by nonanticoagulated blood drawn directly from an antecubital vein by a pump positioned distal to the perfusion chamber. Such a pre-exposure of the procoagulant surface to iodixanol reduced the fibrin deposition around the platelet thrombi by 50% (p<0.01). However, iohexol and ioxaglate did not affect fibrin deposition. None of the 3 CM affected the recruitment of platelets in the thrombi, since similar values were obtained with pre-exposure to 40 vol% of saline. Conclusion: Iodixanol appears to be most biocompatible with endothelium, and has a moderate inhibitory effect on fibrin deposition in flowing blood. This differs from iohexol, and in particular from ioxaglate, which induce endothelial changes in morphology with no effect on fibrin deposition. Since none of the CM affected the platelet aggregate formation, and since ioxaglate has been reported to have stronger anticoagulant and antithrombotic properties than iodixanol or iohexol in in vitro assays, it is apparent that these properties were not reflected in thrombus formation under the experimental conditions of high arterial shear.

1996 ◽  
Vol 37 (6) ◽  
pp. 954-961 ◽  
Author(s):  
R. M. Barstad ◽  
M. S. Buchmann ◽  
M. J. A. G. Hamers ◽  
L. Örning ◽  
U. Ørvim ◽  
...  

2011 ◽  
Vol 31 (8) ◽  
pp. 1772-1780 ◽  
Author(s):  
Erik W. Holy ◽  
Marc Forestier ◽  
Eva K. Richter ◽  
Alexander Akhmedov ◽  
Florian Leiber ◽  
...  

Blood ◽  
1991 ◽  
Vol 77 (5) ◽  
pp. 1006-1012 ◽  
Author(s):  
AB Kelly ◽  
UM Marzec ◽  
W Krupski ◽  
A Bass ◽  
Y Cadroy ◽  
...  

Abstract To determine the role of thrombin in high blood flow, platelet- dependent thrombotic and hemostatic processes we measured the relative antithrombotic and antihemostatic effects in baboons of hirudin, a highly potent and specific antithrombin, and compared the effects of heparin, an antithrombin III-dependent inhibitor of thrombin. Thrombus formation was determined in vivo using three relevant models (homologous endarterectomized aorta, collagen-coated tubing, and Dacron vascular graft) by measuring: (1) platelet deposition, using gamma camera imaging of 111In-platelets; (2) fibrin deposition, as assessed by the incorporation of circulating 125I-fibrinogen; and (3) occlusion. The continuous intravenous infusion of 1, 5, and 20 nmol/kg per minute of recombinant hirudin (desulfatohirudin) maintained constant plasma levels of 0.16 +/- 0.03, 0.79 +/- 0.44, and 3.3 +/- 0.77 mumol/mL, respectively. Hirudin interrupted platelet and fibrin deposition in a dose-dependent manner that was profound at the highest dose for all three thrombogenic surfaces and significant at the lowest dose for thrombus formation on endarterectomized aorta. Thrombotic occlusion was prevented by all doses studied. In contrast, heparin did not inhibit either platelet or fibrin deposition when administered at a dose that maximally prolonged clotting times (100 U/kg) (P greater than .1), and only intermediate effects were produced at 10-fold that dose (1,000 U/kg). Moreover, heparin did not prevent occlusion of the test segments. Hirudin inhibited platelet hemostatic function in concert with its antithrombotic effects (bleeding times were prolonged by the intermediate and higher doses). By comparison, intravenous heparin failed to affect the bleeding time at the 100 U/kg dose (P greater than .5), and only minimally prolonged the bleeding time at the 1,000 U/kg dose (P less than .05). We conclude that platelet-dependent thrombotic and hemostatic processes are thrombin-mediated and that the biologic antithrombin hirudin produces a potent, dose-dependent inhibition of arterial thrombus formation that greatly exceeds the minimal antithrombotic effects produced by heparin.


Blood ◽  
1989 ◽  
Vol 74 (5) ◽  
pp. 1644-1650 ◽  
Author(s):  
BS Schwartz ◽  
JD Bradshaw

Abstract Fibrin is a hallmark of immune-mediated tissue lesions. The presence of fibrin in such lesions implies both the formation of fibrin via coagulation and the accompanying restriction of fibrinolysis, allowing fibrin to persist. Previous work has shown that human monocytes exposed to an inflammatory stimulus such as lipopolysaccharide (LPS) produce both tissue factor (TF) and plasminogen activator inhibitor--type 2 (PAI-2). These two proteins favor fibrin deposition, and evidence implies that cellular production of these two molecules may be linked. Another proinflammatory process pertinent to immune-mediated tissue damage and fibrin deposition is the response to alloantigen. Peripheral- blood mononuclear cells (PBM), consisting of lymphocytes and monocytes together, responded to alloantigen stimulation with differential expression of TF and PAI-2. PBM exposed to alloantigen developed high levels of TF activity, with no concomitant increase in PAI-2 activity or antigen. Alloantigen-stimulated PBM did not accumulate intracellular PAI-2, nor did they degrade PAI-2 added to cultures. This lack of PAI-2 production was not due to inadequate stimulation, as tritiated thymidine uptake and TF production demonstrated recognition of, and a vigorous reaction to, alloantigen. The divergent TF and PAI-2 responses of PBM exposed to alloantigen was maintained over 5 days and was reflected by mRNA profiles. These results imply that under specific physiologically relevant conditions, the procoagulant and antifibrinolytic effectors of inflammatory mononuclear cells can be independently regulated. This would imply more flexibility to monocyte mechanisms that favor fibrin deposition than previously thought.


1998 ◽  
Vol 79 (01) ◽  
pp. 162-168 ◽  
Author(s):  
J. P. Bossavy ◽  
K. S. Sakariassen ◽  
A. Barret ◽  
B. Boneu ◽  
Y. Cadroy

SummaryNo quantitative, simple and non-radioactive method has been described for measuring the platelet content of experimental thrombi. The aim of the present study was to develop a simple method for quantifying platelets in thrombi formed on thrombogenic surfaces in flowing native human blood. To test the relevance of this new method, the effect of unfractionated heparin on arterial thrombus formation was investigated. Tissue factor (TF)- and collagen-coated coverslips were exposed to non-anticoagulated blood at an arterial wall shear rate (2,600 s–1) for 1 to 4 min. Platelet deposition was quantified by measuring the P-selectin (PS) and β-thromboglobulin (βTG) content of dissolved plasmin-digested thrombi using immunoenzymoassays; fibrin deposition was determined by measuring the D-dimer levels. These results were compared to those established by morphometrical analysis.Morphometric evaluation showed that fibrin deposition was maximum on TF by 1 min perfusion time. Platelets deposited subsequently and reached a maximum at 3 min. On collagen, platelets deposited directly on the collagen fibrils without detectable fibrin deposit. Platelet deposition increased from 1 to 4 min. Platelet deposition quantified by PS was correlated to the values obtained by morphometry (r = 0.72, r = 0.67, p <0.001, on TF and collagen, respectively). As compared to PS, βTG measurements gave an underestimation of the size of the thrombus platelet number. Unfractionated heparin infused through a mixing device proximal to the perfusion chamber to obtain plasma concentrations of 0.5, 1 and 3 IU/ml, reduced fibrin deposition on TF-coated coverslips in a dose-dependent manner (77% reduction at 3 IU/ml, p <0.01), but had no significant effect on platelet deposition (33% at 3 IU/ml, p >0.05). In contrast, heparin had no effect on fibrin or platelet deposition on collagen-coated coverslips.Thus, a new quantitative and simple method for measuring platelet deposition in flowing blood has been developed and characterized. Utilizing this system, we have demonstrated that unfractionated heparin did not inhibit arterial thrombus formation either on procoagulant or on proaggregant surface.


2002 ◽  
Vol 93 (3) ◽  
pp. 829-833 ◽  
Author(s):  
Yves Cadroy ◽  
Fabien Pillard ◽  
Kjell S. Sakariassen ◽  
Claire Thalamas ◽  
Bernard Boneu ◽  
...  

We have investigated the effect of moderate and strenuous exercise on experimental arterial thrombus formation in men. Thrombogenesis was measured in 15 sedentary healthy male volunteers at rest or immediately after two standardized exercise tests performed for 30 min on a bicycle ergometer. The exercises were performed at a constant load corresponding to either 50 or 70% maximal oxygen uptake. Thrombus formation was induced ex vivo by exposing a collagen-coated coverslip in a parallel plate perfusion chamber to native nonanticoagulated blood for 3 min. The shear rate at the collagen surface was 2,600 s−1. Platelet and fibrin deposition was quantified by immunoenzymatic methods. The results show that moderate exercise did not affect arterial thrombus formation. In contrast, platelet thrombus formation on collagen was increased on the average by 20% after 30 min at 70% maximal oxygen uptake ( P = 0.03). Fibrin deposition on collagen remained unchanged with exercise, regardless of its intensity. Thus, with the use of a clinically relevant human experimental model of thrombosis, the present study suggests that exercise of heavy intensity may increase the risk for arterial thrombogenesis in sedentary young healthy male volunteers.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 218-218
Author(s):  
T. Regan Baird ◽  
David Gailani ◽  
Bruce Furie ◽  
Barbara C. Furie

Abstract Tissue factor exposure at sites of vascular injury results in the generation of factor Xa and thrombin. A current model of blood coagulation suggests that the amount of thrombin generated through this pathway is limited by the inhibition of the factor VIIa-tissue factor complex by tissue factor pathway inhibitor in the presence of factor Xa. The initial thrombin activates a number of hemostatic proteins including factor XI. Factor XIa then activates factor IX leading to generation of the tenase complex to maintain the thrombin flux. While in vitro studies support this hypothesis the importance of factor XI for thrombus formation in vivo remains unclear. We have examined thrombus formation upon laser injury to the arterioles (30–50 μm diameter) of the cremaster muscle in living mice lacking factor XI using digital multi-channel fluorescence intravital microscopy. Platelets were labeled with Alexa 488 conjugated murine CD41 Fab fragments by systemic infusion of the antibody. Maximum platelet accumulation in factor XI null mice (median of 35 thrombi in 4 mice) is only 25% of that of wild type mice (median of 40 thrombi in 4 mice) after injury (p<0.03). The time course of platelet accumulation is similar between both genotypes. Maximum platelet accumulation occurs in approximately 90 seconds (p<0.2). Fibrin deposition was observed simultaneously using an Alexa 660 conjugated anti-fibrin antibody that does not recognize fibrinogen. Maximum fibrin deposition in factor XI null mice is 50% that of wild type mice (p<0.001) and the rate of fibrin generation is slower in factor XI null mice. However, the time to achieve half maximal fibrin deposition is approximately the same in factor XI null mice (77 sec) compared to wild type mice (63.5 sec, p<0.09). These data suggest that the primary difference in response to laser induced injury between the factor XI null mice and wild type mice is the level of thrombin generated and supports the hypothesis that factor XI participates in maintaining thrombin flux after inhibition of the factor VII-tissue factor. The model above postulates a single source of tissue factor, the vessel wall, and further, that the tissue factor-factor VIIa complex formed from the exposed tissue factor is rapidly inactivated by tissue factor pathway inhibitor after the appearance of the initial factor Xa formed. In addition it has been suggested that a rapidly growing thrombus blocks access to vascular wall tissue factor. However we have recently observed that there is a P-selectin and P-selectin glycoprotein ligand 1 dependent pathway of blood coagulation that recruits blood borne tissue factor into a growing thrombus at sites of laser-induced vessel injury. Both vessel wall and blood borne tissue factor are required for normal thrombus formation. Our data suggest that although tissue factor is continuously recruited to the growing thrombus, factor XIa plays a significant role in thrombin generation.


2019 ◽  
Vol 8 (12) ◽  
pp. 2072 ◽  
Author(s):  
Luca Liberale ◽  
Erik W. Holy ◽  
Alexander Akhmedov ◽  
Nicole R. Bonetti ◽  
Fabian Nietlispach ◽  
...  

CANTOS reported reduced secondary atherothrombotic events in patients with residual inflammatory risk treated with the inhibitory anti-IL-1β antibody, Canakinumab. Yet, mechanisms that underlie this benefit remain elusive. Recent work has implicated formation of neutrophil extracellular traps (NETosis) in arterial thrombosis. Hence, the present study explored the potential link between IL-1β, NETs, and tissue factor (TF)—the key trigger of the coagulation cascade—in atherothrombosis. To this end, ST-elevation myocardial infarction (STEMI) patients from the Swiss multicenter trial SPUM-ACS were retrospectively and randomly selected based on their CRP levels. In particular, 33 patients with STEMI and high C-reactive protein (CRP) levels (≥ 10 mg/L) and, 33 with STEMI and low CRP levels (≤ 4 mg/L) were investigated. High CRP patients displayed elevated circulating IL-1β, NETosis, and NET-associated TF plasma levels compared with low CRP ones. Additionally, analysis of patients stratified by circulating IL-1β levels yielded similar results. Moreover, NETosis and NET-associated TF plasma levels correlated positively in the whole population. In addition to the above, translational research experiments provided mechanistic confirmation for the clinical data identifying IL-1β as the initial trigger for the release of the pro-coagulant, NET-associated TF. In conclusion, blunted TF presentation by activated neutrophils undergoing NETosis may provide a mechanistic explanation to reduced secondary atherothrombotic events as observed in canakinumab-treated patients in CANTOS.


2011 ◽  
Vol 33 (1) ◽  
pp. 6-15 ◽  
Author(s):  
Nicholas Pugh ◽  
Gavin E. Jarvis ◽  
Annelize Koch ◽  
Kjell S. Sakariassen ◽  
Bill Davis ◽  
...  

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