Stephan Hornykewycz

Propofol reduces the migration of human leukocytes through endothelial cell monolayers

OBJECTIVE To test propofol and the solvent of propofol on leukocyte function in the presence of endothelial cell monolayers. The interactions of leukocytes with endothelial cells play a tremendous role during inflammation. Previous studies have investigated the influence of propofol on leukocytes. DESIGN Prospective, controlled study. SETTING University research laboratories. SUBJECTS Seven independent experiments were performed to investigate the influence of propofol (0.4, 4, and 40 ng/mL) on the migration of human leukocytes through human endothelial cell monolayers. Moreover, the authors tested the solvent of propofol on leukocyte migration. INTERVENTIONS Human endothelial cell monolayers and/or human leukocytes were preincubated with clinically relevant higher and lower concentrations of propofol. The amount of leukocyte migration after 3 hrs was measured with a fluorometer. MEASUREMENTS AND MAIN RESULTS Human endothelial cells isolated from umbilical veins were cultured on microporous membranes until they formed an endothelial cell monolayer. Leukocytes were separated by standard procedures. The migration of leukocytes through monolayers of endothelial cells using the clinically relevant concentration of propofol was reduced to 93% +- 3.8% (so; p < .05) when the leukocytes but not the endothelial cell monolayers were preincubated with propofol. Leukocyte migration was reduced to 80% - 5.9% (p < .05) when only monolayers of endothelial cells were treated with propofol, and was reduced to 73% + 10.4% (p < .05) when both leukocytes and monolayers of endothelial cells were treated with propofol. The higher and lower concentrations showed a dose-dependent effect. The solvent of propofol had no significant effect. CONCLUSION The authors investigated the influence of propofol and its solvent on the interaction between both cell systems-leukocytes and endothelial cells. Propofol is able to reduce significantly the migration of leukocytes through endothelial cell monolayers. The use of different doses revealed a dose-dependent effect. The current model allowed treatment of one cell type: leukocyte or endothelial cell. The results of this investigation indicate that the influence of propofol on leukocyte migration affects endothelial cells more than leukocytes.

Concentration of Endogenous tPA Antigen in Coronary Artery Disease Relation to Thrombotic Events, Aspirin Treatment, Hyperlipidemia, and Multivessel Disease

Tissue plasminogen activator (tPA) is the major plasminogen activator responsible for dissolving blood clots found in blood vessels. However, elevated concentrations of tPA antigen were found to be related to adverse events in patients with coronary artery disease (CAD). Considerable controversy about the significance of these results exists. The goal of this cross-sectional study was to identify independent determinants for tPA antigen concentrations in patients with CAD, to possibly clarify the above paradoxical relationship. The baseline tPA antigen concentrations of 366 patients with angiographic evidence of coronary sclerosis were determined. Univariate analysis showed that age (P=0.013), angiographic extent of disease (P<0.001), presence of angina at rest (P<0.001), diabetes mellitus (P=0.004), hypercholesterolemia (P=0. 045), hypertriglyceridemia (P=0.015), and chronic intake of nitrates (P<0.001) were significantly and positively related to tPA antigen concentration, while the chronic intake of aspirin was inversely related to tPA antigen (P<0.001). In addition, plasminogen activator inhibitor type 1 (PAI-1) activity was found to be significantly and positively associated with tPA antigen concentration (P<0.001). A multivariate analysis identified chronic low-dose aspirin therapy (P<0.001), PAI-1 activity (P<0.001), hypertriglyceridemia (P=0.005), the type of angina (P=0.026), multivessel disease (P=0.041), and hypercholesterolemia (P=0.043) as significant and independent determinants of tPA antigen. While hypertriglyceridemia and hypercholesterolemia both are related to the underlying disease, the type of angina and the number of involved vessels are linked to the severity and extent of disease, and all of them are indicators of a prothrombotic state found during the progression of CAD. In contrary, low-dose aspirin rather would decrease the likelihood of thrombotic events. The relation of tPA antigen to PAI-1 activity furthermore underlines the relation between tPA antigen concentration and a prothrombotic state. Therefore, the positive or-in case of aspirin therapy-negative correlation of these parameters with tPA antigen concentration would indicate that thrombus formation and simultaneous endothelial cell activation might be major determinants for tPA antigen concentration in CAD.

Hydroxyethyl starch reduces the chemotaxis of white cells through endothelial cell monolayers

BACKGROUND: Polymorphonuclear leukocytes (PMNs) play a tremendous role during inflammatory processes. PMNs have to pass a monolayer of endothelial cells to migrate into the extravascular space. Hydroxyethyl starch (HES) is frequently used as a volume expander in critically ill patients.

Homocysteine Plasma Levels in Young Patients with Coronary Artery Disease: Relation to History of Acute Myocardial Infarction and Anatomical Extent of Disease

Although there is considerable epidemiologic evidence for a relationship between plasma homocysteine (Hcy) levels and cardiovascular disease, not all prospective studies have shown such a relationship. Furthermore, data concerning the role of hyperhomocysteinemia in patients with premature coronary artery disease (CAD) are rare. It was the aim of the study to investigate a possible association between Hcy plasma levels in young patients with the extent of CAD and the history of myocardial infarction (MI). A cohort of 94 patients was examined for conventional risk factors and the history of previous transmural MI. Furthermore, coronary angiography was performed to assess the anatomical extent of vessel disease. Plasma Hcy levels were measured by use of a commercial enzyme-linked immunosorbent assay. Only a history of previous MI was significantly associated with hyperhomocysteinemia. There was no relationship between elevated Hcy levels and the anatomical extent of vessel disease in patients with premature CAD. Our data may indicate that hyperhomocysteinemia represents an independent risk factor for acute coronary thrombosis rather than for the development of coronary sclerosis. Thereby, hyperhomocysteinemia may influence the clinical situation after plaque rupture not only by prothrombotic action but also by favouring endothelial dysfunction and vasospasm.

EVALUATION OF BEDSIDE PROTHROMBIN TIME AND ACTIVATED PARTIAL THROMBOPLASTIN TIME MEASUREMENT BY COAGULATION ANALYZER COAGUCHECK PLUS® IN VARIOUS CLINICAL SETTINGS

In the present study CoaguCheck Plus (CCP), a coagulation test system using whole blood, was evaluated with respect to its comparability with widely distributed conventional routine coagulation assays. A correlation of r = 0.997 (p < 0.0001) was found between INR of CCP-prothrombin time (CCP-PT) and Thrombotest (KC-1 analyzer) in patients on oral anticoagulant therapy. A correlation of r = 0.899 (p < 0.001) between CCP-aPTT and Actin ES aPTT (STA analyzer) was found in heparinized patients. Impaired hepatic hepatic coagulation factor synthesis in liver cirrhosis patients was detected by CCP-PT with a sensitivity of 0.75 and by Normotest (STA analyzer) with a sensitivity of 0.92. Those patients with normal CCP-PT values and liver disease had, only mild reductions (> 30% of normals) in coagulation factors II, V, VII or X. CCP-aPTT was also performed in patients with a deficiency in the so called endogenous coagulation factors VIII, IX, XI and XII. CCP-aPTT showed a sensitivity similar to that of Actin FS aPTT in the detection even of mild deficiencies in factors VIII, IX and XII; factor XI deficiency was however detected only in patients with severe (< 12% of normals) disease; lupus anticoagulants were detected with a high sensitivity.

Tissue-type plasminogen activator and Type-1 plasminogen activator inhibitor in patients with coronary artery disease — Relations to clinical variables and cardiovascular risk factors

Summary In this study we investigated associations of the fibrinolytic parameters t-PA antigen and PAI-1 activity in 317 patients with angiographically proven coronary artery disease with gender, age classes, angiographic extent of disease, symptom class and history of myocardial infarction as clinical parameters, as well as with the established cardiovascular risk factors: smoking, arterial hypertension, cholesterol levels, triglyceride levels, obesity and diabetes mellitus, by use of univariate and multifactorial analysis, respectively. While PAI-1 activity was only associated with unstable angina, t-PA antigen was significantly associated with hypertriglyceridemia, unstable angina, and angiographic extent of disease.

Thrombus formation on the balloon of heparin-bonded pulmonary artery catheters: an ultrastructural scanning electron microscope study.

Objective: To investigate heparin‐bonded pulmonary artery catheters with respect to thrombus formation and platelet aggregation at the balloon and the shaft using a scanning electron microscope in critically ill patients. Design: Prospective study. Settings: Critical care unit and research laboratories. Patients: Pulmonary artery catheters were inserted in critically ill patients (n = 10). Interventions: Pulmonary artery catheters were removed after 24, 48, 72, or 120 hrs, and the ultrastructure was investigated in specialized research laboratories. Measurements and Main Results: Balloon and shaft were investigated using a scanning electron microscopic technique. Area of thrombus formation was quantified using image analysis. Heparin release of the catheters was measured. The frequency of balloon inflations was investigated in in vitro experiments by inflating catheters different times (0, 10, 20, and 30 times). Twenty‐four hours after catheter insertion, scanning electron microscopic images showed thrombus formation and platelet aggregation at the site of the balloon. Seventy‐two hours after catheter insertion, a thrombus started to detach. The areas of thrombus formation did not differ, but thrombus organization changed dramatically 72 and 120 hrs after catheter insertion. The shaft was colonized by single cells only. Cracks of the balloon could be observed after 72 hrs, whereas no cracks could be found in in vitro controls. In vitro, heparin release of the pulmonary artery catheters decreased significantly after 24 hrs. Conclusions: Scanning electron microscopic images of heparin‐bonded pulmonary artery catheters demonstrate thrombus formation on the balloon 24 hrs after pulmonary artery catheter insertion, increasing dramatically at 72 and 120 hrs. The shaft was colonized by single cells only. The thrombus size is not significantly different during the observation time, but the grade and quality of thrombus formation differ.

Pre-existing anticardiolipin antibodies and development of restenosis after coronary balloon angioplasty : predictive value for a complicated course?

Immune mechanisms play a critical role in cardiovascular disease. Cardiolipins are candidate autoantigens with a prothrombotic activity of their corresponding antibodies. We investigated the influence of pre-existing immunoglobulin (Ig)M and IgG anticardiolipin (aCL) antibodies on restenosis after coronary balloon angioplasty and their interaction with tissue plasminogen activator, plasminogen activator inhibitor type-1, von Willebrand factor and lipoprotein (a) in 132 patients with stable angina pectoris using immunoassays. Thirty percent of patients developed angiographically proven restenosis estimated by three independent experienced angiographers; 12% of all patients developed recurrent restenoses at the same site during a follow-up period of 2 years. Circulating IgM aCL antibodies categorized by quartiles predicted recurrent restenoses (logistic regression, for trend P < 0.04) with an increase of relative risk (RR) per quartile of 2.09. The predictive value of IgM aCL antibodies was unchanged adjusting for established cardiovascular risk factors (P = 0.028, RR = 2.69), extent of coronary artery disease (P = 0.014, RR = 2.73) and inflammatory parameters (P = 0.025, RR = 2.79), but lost significance adjusting for other prothrombotic parameters (P = 0.24, RR = 1.76). IgM aCL antibodies positively correlated with lipoprotein (a) (r = 0.23, P = 0.04). However, there was no significant interaction between their influences on recurrent restenoses. The other prothrombotic parameters did not predict single or recurrent restenoses. In conclusion, IgM aCL antibodies may help to identify a group of patients at high risk for recurrent restenoses after coronary balloon angioplasty.

Laboratory monitoring of success and failure of thrombolytic therapy in acute myocardial infarction

Summary In clinical practice it would be desirable to monitor the clinical course and outcome of thrombolytic therapy by use of non-invasive laboratory methods. From the test systems available, the determination of specific myocardial necrosis markers seem to be at the moment of highest clinical value. Markers of thrombin activation might indicate failure of therapy and/or tendency for thrombotic reocclusion with all commercially available fibrin specific or non-specific thrombolytic agents but have failed to be of prognostic value for the individual patient or have not been investigated in sufficient numbers of patients. No clinical usefulness has been found so far for determination of markers of plasmin activation. Accordingly, specific control parameters of thrombolytic therapy with rt-PA have not been shown to be useful as predictive marker for clinical outcome of thrombolytic therapy in the individual patient with acute myocardial infarction. However, determination of t-PA and PAI-1 plasma levels is of interest with respect to investigation of pathophysiological contexts and their influence on efficacy of thrombolysis and should, therefore, be taken into account in clinical trials using t-PA or related substances for thrombolytic therapy.