thromboplastin and iodixanol

To investigate the influence of two non-ionic radiographic contrast media with different osmolality on thrombocytic function and the plasmatic coagulation system.. The study was carried out as a randomised, prospective, comparative study with two contrast media in a heart catheter laboratory.. Activating influences on platelet aggregation, procoagulatory or profibrinolytic functions or injury to the endothelium could be ruled out. Apparently, also differences in substance properties, such as the media's ionic character or osmolality had no demonstrable influence on the interaction with haemostatis and blood vessels. An adjuvant, antithrombotic therapy was carried out, which consisted of platelet aggregation inhibitors and heparins.. Our findings agree with the results of recent clinical trials, which demonstrated no relevant disadvantage of non-ionic contrast media as regards thrombotic complications.

Topics: Angioplasty, Balloon, Coronary; Antithrombin III; Contrast Media; Coronary Angiography; Female; Fibrin Fibrinogen Degradation Products; Hemostasis; Humans; Male; Middle Aged; Osmolar Concentration; Peptide Hydrolases; Platelet Aggregation; Prospective Studies; Prothrombin; Thrombomodulin; Thromboplastin; Triiodobenzoic Acids

Islet isolation and purification using a continuous density gradient may reduce the volume of tissue necessary for implantation into patients, therefore minimizing the risks associated with intraportal infusion in islet transplantation. On the other hand, the purification procedure might result in a decreased number of islets recovered due to various stresses such as exposure to cytokine/chemokine. While a Ficoll-based density gradient has been widely used in purification for clinical trials, purification with iodixanol (OptiPrep) has been recently reported in islet transplant series with successful clinical outcomes. The aim of the current study was to compare the effects of the purification method using OptiPrep-based and Ficoll-based density gradients. Human islet isolations were performed using a modified automated method. After the digestion phase, pre-purification digests were divided into two groups and purified using a semiautomated cell processor with either a continuous Ficoll- or OptiPrep-based density gradient. The quantity, purity, viability, and cellular composition of islet preparations from each group were assessed. Cytokine/chemokine and tissue factor production from islet preparations after 48-h culture were also measured. Although islet purity, post-purification IEQ, islet recovery rate, FDA/PI, and fractional β-cell viability were comparable, β-cell mass after 48-h culture significantly improved in the OptiPrep group when compared to the Ficoll group. The production of cytokine/chemokine including IL-1β, TNF-α, IFN-γ, IL-6, IL-8, MIP-1β, MCP-1, and RANTES but not tissue factor from the OptiPrep group was significantly lower during 48-h culture after isolation. Each preparation contained the similar number of ductal cells and macrophages. Endotoxin level in both gradient medium was also comparable. The purification method using OptiPrep gradient media significantly reduced cytokine/chemokine production but not tissue factor from human islet preparations and improved β-cell survival during pretransplant culture. Our results suggest that the purification method using OptiPrep gradient media may be of assistance in increasing successful islet transplantation.

Topics: Adolescent; Adult; Animals; Anti-Inflammatory Agents; Cell Separation; Cell Survival; Cells, Cultured; Centrifugation, Density Gradient; Chemokines; Contrast Media; Cytokines; Female; Humans; Insulin-Secreting Cells; Islets of Langerhans; Islets of Langerhans Transplantation; Male; Mice; Mice, Nude; Middle Aged; Thromboplastin; Triiodobenzoic Acids

There is a dispute about the potential effects of radiographic contrast media (CM) on thrombogenesis. The nonionic CM iohexol triggers platelet beta-thromboglobulin (beta-TG) secretion, and thus may activate the platelets and promote thrombosis. We addressed this topic in a study employing a human model of arterial thrombus formation in the presence of aspirin and heparin. This was a follow-up to our initial study (on thrombus formation in native blood) which did not include antithrombotic drugs. The nonionic CM iohexol (monomer) and iodixanol (dimer) and the ionic CM ioxaglate (dimer) were compared.. Thrombus formation was triggered by a surface rich in either collagen or tissue factor, positioned in a parallel-plate perfusion chamber device at an arterial wall shear rate of 2600 s-1. Blood from healthy volunteers, following ingestion of 1 g aspirin, was mixed with 40 vol% CM and 2.0 IU/ml heparin and passed over the surfaces. Thrombus formation in the presence of either CM showed no difference, despite the fact that iohexol triggered a pronounced platelet beta-TG secretion; iodixanol or ioxaglate were virtually inert.. There was no association between iohexol-induced beta-TG secretion and thrombus formation on collagen (platelet-driven) or on tissue factor (thrombin-driven) in the presence of a standard antithrombotic regimen of aspirin and heparin as used in the clinic. The notion of a thrombotic risk due to platelet activation by iohexol was thus not substantiated by this study.

Topics: Anticoagulants; Aspirin; beta-Thromboglobulin; Blood Platelets; Collagen; Contrast Media; Drug Interactions; Heparin; Humans; In Vitro Techniques; Iohexol; Ioxaglic Acid; Male; Platelet Activation; Thromboplastin; Thrombosis; Triiodobenzoic Acids

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.. 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.. 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.

Topics: Angioplasty, Balloon, Coronary; Cells, Cultured; Contrast Media; Endothelium, Vascular; Female; Humans; Iohexol; Ioxaglic Acid; Male; Plasminogen Activator Inhibitor 1; Thrombomodulin; Thromboplastin; Thrombosis; Tissue Plasminogen Activator; Triiodobenzoic Acids