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Bernd Jilma

Publications and source records attributed to Bernd Jilma.

At least 73 records · Page 4Linked to original sources
PubMed2003

Validation of a novel tissue factor assay in experimental human endotoxemia.

BACKGROUND: Nuclear factor kappa B (NF-kappa B) activation and tissue factor (TF) expression may contribute to lethality in sepsis. Inappropriate in vivo expression of TF is likely responsible for fibrin deposition in sepsis-associated disseminated intravascular coagulation (DIC). Clinical assessment of TF expression has remained a major challenge. No point-of-care assays are currently available to measure the level of TF activity in whole blood. The current study examined the suitability of the TiFaCT assay as a point-of-care assay to detect TF expression. METHODS: 30 healthy male volunteers received 2 ng/kg of LPS. Tissue factor-dependent coagulation was quantified with a novel assay called tissue factor clotting time (TiFaCT), and by measurement of activation markers of downstream coagulation. RESULTS: Ex vivo addition of anti-TF antibodies to blood slightly increased clotting times at 0-24 h (p<0.01) indicating that some tissue factor activity was present in whole blood at any time. LPS bolus infusion decreased TiFaCT clotting time by -23% compared to baseline (p<0.01), when in vivo clotting increased, as demonstrated by a 10-fold increase in prothrombin fragment levels (F1+2). Ex vivo incubation with LPS considerably shortened TiFaCT (from 1000s to 400s as compared to control incubation; p<0.01). This effect was blunted at 2-4 h after LPS infusion (i.e. the time of monocytopenia), but twofold enhanced 24 h after LPS challenge (p<0.01). CONCLUSIONS: In summary, the TiFaCT assay was validated in our in vivo model of LPS-induced coagulation. It detected minute quantities of circulating TF even at baseline. TiFaCT is shortened at times of in vivo thrombin generation.

Adult↗
PubMed2003

Influence of tiapride on platelet counts in healthy volunteers and patients with movement disorders.

BACKGROUND: The selective D2 antagonist tiapride is administered in various movement disorders. Furthermore, there are indications that tiapride increases platelet counts. AIM: To characterize tiapride's potential to increase platelet counts in healthy subjects and patients with movement disorders. METHODS: In Part A, 10 healthy volunteers received tiapride (300 mg/day) for 21 days in a longitudinal, prospective, open trial. One hundred healthy subjects served as controls. Part B was a retrospective analysis of 15 patients with movement disorders on tiapride [Huntington's disease (n=6), Morbus Little (n=3), hyperkinetic syndromes of undetermined etiology (n=3), blepharospasm (n=1), cervical dystonia (n=1), perioral dyskinesia (n=1)] and 15 age- and sex-matched controls. RESULTS: Part A: Although serum prolactin levels increased by 526+/-14%, confirming good drug compliance, tiapride elicited only minor changes in platelet counts. Part B: Platelet counts correlated positively with the dose of tiapride (100-800 mg/day; r=.67; P=.007). Platelet counts were significantly higher in patients on tiapride compared to healthy age-matched controls (P<.001). Four patients responded to an increase in the tiapride dosage with an increase in platelet count by 97-173 cells/nl. CONCLUSION: Three weeks of treatment with tiapride (300 mg/day) is insufficient to elevate platelet counts to a clinically relevant extent in young healthy volunteers. However, in elderly patients with movement disorders tiapride treatment is associated with markedly increased platelet counts.

Administration, Oral↗
PubMed2003

Levels of adhesion molecules do not decrease after 3 months of statin therapy in moderate hypercholesterolaemia.

Studies in animals and humans indicate a pivotal role for adhesion molecules (AMs) in the pathogenesis of atherosclerosis. Whereas an association between hypercholesterolaemia and AM expression has been suggested, it is unclear whether lowering cholesterol decreases AM expression and release. We compared the effects of a 3-month treatment with standard doses of three different statins (atorvastatin, simvastatin and pravastatin) on plasma levels of circulating AM (cAM) in 75 hypercholesterolaemic patients in a randomized clinical trial. Plasma levels of circulating (c)E-selectin, circulating intercellular adhesion molecule-1 (cICAM-1) and circulating vascular cell adhesion molecule-1 (cVCAM-1) were measured before and after 3 months of therapy. None of the statins lowered plasma cAM levels and pooled analyses of all patients showed a 1.7% [95% confidence interval (CI), -1.4-4.9%] increase in cE-selectin, a 2.1% (95% CI, -0.2-4.4%) increase in cICAM-1, and a 2.7% (95% CI, -0.6-6.1%) increase in cVCAM-1 levels. cAM levels did not decrease, even in patients with a >50% decrease ( n =19) in low-density lipoprotein cholesterol levels. This study provides strong evidence that 3 months of therapy with three different statins does not decrease cAM levels, despite normalization of cholesterol levels, and a minor decrease in C-reactive protein levels in patients with moderate hypercholesterolaemia.

Adult↗
PubMed2003

Glycoprotein Ib polymorphisms influence platelet plug formation under high shear rates.

Platelet polymorphisms (Kozak, VNTR and HPA-2) within glycoprotein (GP)Ib alpha may be associated with an increased risk of arterial thrombosis. However, the functional role of these polymorphisms has not been clarified. Their influence on platelet plug formation under high shear rates was, therefore, examined in 233 healthy individuals. Collagen-adrenaline-induced closure time was shorter in carriers of the C/D versus C/C VNTR allele and in homozygotes with the (-5)T/T versus (-5)C/T Kozak genotype as determined by novel polymerase chain reaction methods. The HPA-2 genotype had no effects, and the density of GPIb alpha molecules was not influenced by GPIb alpha genotypes.

Adult↗
PubMed2003

Endotoxaemia modulates Toll-like receptors on leucocytes in humans.

The modulation of Toll-like receptors (TLR) 1, 2 and 4 was studied during experimental human endotoxaemia. Healthy volunteers received 2 ng/kg of lipopolysaccharide (LPS) endotoxin (n = 10). TLR1, 2 and 4 expression occurred on monocytes and neutrophils, with monocytes expressing higher baseline levels of TLR2. LPS infusion downmodulated TLR4 expression on neutrophils, with maximal downregulation occurring at 24 h (-62% from baseline; P < 0.03 versus baseline). Monocyte TLRs were upregulated in vivo (TLR1 and 2), and in vitro (TLR1, 2 and 4) 8 h after LPS bolus (P < 0.05 versus baseline). Therefore, neutrophils and monocytes differentially express surface TLRs, and endotoxaemia differentially regulates TLR expression.

Adult↗
PubMed2003

Activation of calcium-dependent calmodulin by calcium(II)3(3,5-diisopropylsalicylate)6(H2O)6 decreases thrombin receptor activating peptide-induced P-selectin expression.

We examined the influence of 3,5-diisopropylsalicylic acid (3,5-DIPS) and calcium(II)3 (3,5-diisopropylsalicylate)6 (H2 O)6 [Ca(II)3 (3,5-DIPS)6 ], a new activator of calcium-dependent calmodulin-triggered nitric oxide synthase, on thrombin-induced platelet P-selectin expression. Citrated whole blood samples were incubated with either ethanol vehicle, 3,5-DIPS, or Ca(II)3 (3,5-DIPS)6. These whole blood samples were also co-incubated with thrombin receptor activating peptide (TRAP) or adenosine diphosphate (ADP), to up-regulate P-selectin (CD62P) on platelets. Both TRAP and ADP up-regulated P-selectin on platelets compared with platelets in whole blood samples that were not incubated with either platelet activator. Co-incubation of whole blood samples with TRAP, ADP together with 3,5-DIPS, or Ca(II)3 (3,5-DIPS)6 revealed that Ca(II)3 (3,5-DIPS)6 caused a decrease in platelet P-selectin expression for TRAP, ADP, and no-activator co-incubated samples of whole blood. Incubation of platelets with 3,5-DIPS also caused a decrease in ADP-induced up-regulation of P-selectin but failed to affect TRAP or no-activator-treated platelets. Incubation of whole blood with Ca(II)3 (3,5-DIPS)6 induced some hemolysis. We found that hemolysis increases basal P-selectin expression on platelets. We therefore conclude that Ca(II)3 (3,5-DIPS)6 decreased not only basal, but also hemolysis-induced P-selectin expression on platelets. In contrast, incubation of haemolysed whole blood with SIN-1 (standard nitric oxide-releasing drug) had no effect on P-selectin expression. In summary, Ca(II)3 (3,5-DIPS)6, a new calmodulin-dependent nitric oxide synthase activator, decreases P-selectin expression of human platelets in response to thrombin receptor activation. Improved calcium-dependent calmodulin activators may become useful drugs for the treatment of disorders associated with platelet activation, and P-selectin may decrease expression due to hemolysis.

Adenosine Diphosphate↗
PubMed2003

Evaluation of antiinflammatory and antiadhesive effects of heparins in human endotoxemia.

OBJECTIVE: Cytokines and adhesion molecules have a decisive role in the development of early inflammatory response as well as the late sequelae of sepsis. Because L-selectin-deficient mice are protected from lethal endotoxemia, blockade of L-selectin may provide a useful therapeutic option in human sepsis. Heparin has immunomodulatory properties and effectively inhibits L- and P-selectin binding in vitro. We therefore investigated whether clinically applied doses of unfractionated or low-molecular-weight heparin affect early inflammatory response in human endotoxemia. DESIGN: The study was randomized, double-blinded, placebo-controlled, in three parallel groups consisting of 30 healthy male volunteers. SETTING: University medical center. INTERVENTIONS: All subjects received a 2-ng/kg intravenous bolus of lipopolysaccharide and 10 mins later unfractionated heparin, low-molecular-weight heparin, or placebo as bolus primed continuous infusion for 6 hrs. MEASUREMENTS AND MAIN RESULTS: Lipopolysaccharide infusion induced similar increases of tumor necrosis factor-alpha, interleukin-6, interleukin-8, C-reactive protein, and soluble E-selectin levels in all treatment groups. CD11b expression increased by approximately 400%, but L-selectin decreased by 41% in the placebo arm 6 hrs after lipopolysaccharide infusion. Interestingly, both heparins (in particular unfractionated heparin) decreased L-selectin down-regulation as compared with placebo. Similarly, the decrease in lymphocyte counts was significantly less in the unfractionated heparin group during the first 24 hrs (p <.05 vs. placebo) CONCLUSIONS: Heparins displayed little effects on cytokine production and endothelial cell activation in endotoxemia. Of note, however, unfractionated heparin reduced L-selectin down-regulation and lymphocytopenia. These could present novel mechanisms of action of unfractionated heparin.

Adult↗
PubMed2003

Enalapril does not alter adhesion molecule levels in human endotoxemia.

The angiotensin-converting enzyme inhibitor (ACE-I) enalapril has been shown to lower elevated levels of circulating adhesion molecules (cAM) in critically ill patients. To delineate the mechanisms of this possibly beneficial effect of enalapril, we studied the acute effects of enalapril in a well-defined model of endotoxin-triggered, cytokine-mediated cAM up-regulation. In a randomized, controlled trial, 30 healthy male volunteers received 2 ng/kg lipopolysaccharide (LPS) after pretreatment with placebo or 20 mg/day enalapril for 5 days or with a single dose of 20 mg of enalapril 2 h before LPS infusion. LPS infusion increased TNF levels 300-fold above normal, circulating (c) E-selectin levels by 425% (CI, 359%-492%), and P-selectin, VCAM-1, ICAM-1, and von Willebrand factor levels by 47%-74%. LPS infusion also enhanced ICAM-1 and CD11b expression 2- to 3-fold on monocytes. However, no differences were seen between treatment groups (P > 0.05), despite 95% inhibition of ACE activity by enalapril. Inhibition of ACE activity by enalapril does not influence plasma indices of endothelial activation after endotoxin infusion in healthy individuals. Our results do not support the concept of a beneficial clinical effect of enalaprilat in septicemia.

Adult↗
PubMed2003

Regulation of Fas (APO-1, CD95) and Fas ligand expression in leukocytes during systemic inflammation in humans.

A potential role of Fas/FasL in sepsis is suggested by recent clinical studies showing that Fas and FasL could serve as markers for severity of sepsis. We sought to determine the effect of endotoxin infusion on expression of Fas and FasL. Healthy volunteers (n = 30) received 2 ng/kg endotoxin i.v. Endotoxin infusion decreased Fas expression on neutrophils and monocytes by 15-20% at 2-4 h in vivo and also in vitro. A rebound increase in Fas (30%) was seen on neutrophils at 24 h, and soluble FasL levels increased by 100% at 24 h. Fas mRNA levels increased 6-fold 4-6 h after endotoxin infusion as measured by real-time polymerase chain reaction. In contrast, FasL-mRNA levels in circulating leukocytes decreased by >80% 2h after lipopolysaccharide infusion. In summary, low-grade endotoxemia induces early down-modulation of Fas on leukocytes, followed by a several-fold increase in Fas-mRNA expression leading to later Fas surface upregulation on neutrophils. The upregulation of Fas expression, Fas mRNA, and later in FasL and sFas levels in endotoxemia replicates the increased fas levels found in septic patients.

Adult↗
PubMed2003

Blockade of GPIIb/IIIa by eptifibatide and tirofiban does not alter tissue factor induced thrombin generation in human endotoxemia.

Activated platelets facilitate thrombin generation by providing a catalytic surface on which coagulation activation occurs. The glycoprotein (GP) IIb/IIIa receptor might play a major role in this process as shown by in vitro and animal experiments. However, it is controversial whether the GPIIb/IIIa receptor facilitates tissue factor-induced thrombin generation in humans as well. We therefore investigated whether two clinically used GPIIb/IIIa antagonists (tirofiban and eptifibatide) may blunt TF-induced coagulation in humans. Thirty male volunteers received 2 ng/kg endotoxin and standard doses of eptifibatide, tirofiban or placebo over 5 hours in a randomized, double-blind, placebo-controlled, double-dummy parallel-group trial. Markers of thrombin generation (prothrombin fragment 1+2, thrombin-antithrombin complexes), fibrinolysis (D-dimer, plasmin-antiplasmin complexes) as well as inflammatory markers (interleukin-6, tumor necrosis factor-alpha) were measured by enzyme linked immunoasssays, TF-mRNA expression was quantified by RT-PCR. Neither eptifibatide nor tirofiban influenced LPS-induced coagulation activation or fibrinolytic activity. Additionally, the increase of TNF-alpha and IL-6 was similar in all groups. In conclusion, GPIIb/IIIa blockade with eptifibatide or tirofiban did not influence TF-induced coagulation activation in human low grade endotoxemia.

Adult↗
PubMed2003

Regulation of protease-activated receptor 1 (PAR1) on platelets and responsiveness to thrombin receptor activating peptide (TRAP) during systemic inflammation in humans.

Thrombin is a coagulation protease that activates platelets, endothelial cells, leukocytes and mesenchymal cells. Thrombin signaling is mediated at least in part by protease-activated receptors (PARs). As little is known about the in vivo regulation of PAR1, this study aimed to characterize the effects of systemic thrombin formation during human endotoxemia on the regulation of PAR1 and the associated responsiveness of human platelets to thrombin receptor activating peptide (TRAP). Endotoxin (2 ng/kg) was infused into 40 healthy men to study the regulation of PAR1 in systemic human inflammation. The SPAN12 antibody was used to determine the in vivo regulation of PAR1. To measure whether modulation of the PAR1 receptor may be associated with altered platelet reactivity, whole blood was stimulated with TRAP ex vivo. Thrombin generation was determined by prothrombin (F(1+2)) fragment. F(1+2) levels increased almost 9-fold from 0.5+/-0.1 nmol/L to 4.5+/-1.9 nmol/L at 4 h (p<0.001). PAR1 decreased by approximately 8% (p<0.001) within 2 h after endotoxin infusion and stayed at those levels until 6 h. Concomitantly, TRAP induced P-selectin expression maximally decreased by 18% (p<0.001) at 6 h. In conclusion, PAR1 expression is down-regulated on platelets during systemic thrombin formation induced by inflammation in humans which results in decreased responsiveness to subsequent stimulation of the PAR1 receptor.

Adult↗
PubMed2002

Effect of factor X inhibition on coagulation activation and cytokine induction in human systemic inflammation.

Anticoagulants have gained increasing attention in the treatment of sepsis. This study used danaparoid to investigate the role of factor Xa in endotoxin-induced coagulation and inflammation and its effectiveness when coagulation activation has already occurred. Thirty healthy volunteers were enrolled in the randomized, placebo-controlled trial. Subjects received 2 ng/kg endotoxin and danaparoid 10 min or 3 h thereafter or placebo. Endotoxin increased prothrombin fragment 1+2 (F(1+2)) levels from 0.5 to 7.0 nmol/L at 5 h in the placebo group. Early danaparoid infusion inhibited endotoxin-induced thrombin formation: maximum F(1+2) levels reached only 1.8 nmol/L (P<.01, vs. baseline or placebo). Delayed danaparoid infusion effectively blocked further thrombin formation. However, danaparoid did not alter endotoxin-induced changes in the fibrinolytic system, cytokine levels, activation of leukocytes, or tissue factor expression on monocytes. Danaparoid therefore selectively attenuates endotoxin-induced coagulopathy, even with delayed administration when coagulation activation is well under way.

Adult↗
PubMed2002

Point of care measurement of lepirudin and heparin anticoagulation during systemic inflammation.

BACKGROUND: The number of indications for recombinant human hirudin lepirudin therapy has increased in recent years, and now includes acute coronary syndromes and heparin-induced thrombocytopenia. Hence, point of care monitoring appears desirable for therapy with lepirudin. As CoaguChek Plus (CCP) provides a rapid bedside test to monitor therapy with other anticoagulants, we aimed to determine its suitability for lepirudin therapy. METHODS: Forty-four healthy volunteers received a 2 ng/kg endotoxin infusion (to induce coagulation) together with clinically relevant doses of lepirudin or heparin in a prospective, placebo-controlled, randomised fashion. Measurements of CCP-partial thromboplastin time (aPTT) were compared to laboratory STA-aPTT. RESULTS: As expected, baseline values of CCP-aPTT were shorter than STA-aPTT. Lepirudin increased CCP-aPTT 3-fold, and STA-aPTT 2-fold 1 h after bolus infusion. During lepirudin infusion, the correlation between CCP-aPTT and STA-aPTT was excellent (r=0.86-0.92). Both methods were equally sensitive to over-anticoagulation with heparin. Acute systemic inflammation had little effects on CCP-aPTT. CONCLUSION: CCP-aPTT is suitable for longitudinal point of care monitoring of lepirudin therapy. As baseline values of CCP-aPTT are shorter than STA-aPTT, it is recommended not to indiscriminately change between methods in the follow-up of individual patients.

Adult↗
PubMed2002

Human monocyte stimulation by experimental whole body hyperthermia.

The thermal effect of fever, an evolutionarily conserved acute-phase response, has been associated with better survival and a shorter duration of disease in cases of infection. The molecular consequence of this beneficial fever response is poorly understood. To determine the influence of hyperthermia on human monocytes, which are important for the recognition and elimination of pathogens, twelve healthy volunteers were immersed in a 39.5 degrees C hot water bath to increase their body temperature. The expression of the endotoxin receptor CD14 and the complement receptor CD11b increased after the hot water bath (P < 0.05), whereas the expression of the selectin CD62L, which mediates the initial attachment of leukocytes at the endothelium during inflammation, was downregulated after hyperthermia (P < 0.05). Comparable changes in monocyte receptor expression were observed after in vitro hyperthermia. Furthermore, 3 hours after in vivo hyperthermia, the response of monocytes to endotoxin was enhanced in an ex vivo lipopolysaccharide stimulation assay, as expressed by a greater TNF-alpha release (P < 0.05). We conclude that the thermal effect of fever directly activates monocytes, which increases their ability to respond to bacterial challenge.

Adult↗
PubMed2002

Leukocyte scintigraphy with 99mTc-exametazime-labeled leukocytes is not useful for follow-up of systemic vasculitis.

BACKGROUND: The prognosis of systemic vasculitis, for instance Wegener's granulomatosis (WG), was greatly improved by the introduction of immunosuppressive treatment. However, relapses are frequent and predictors are scarce. 111In-leukocytes have been found to indicate unknown manifestations of WG and to predict later relapse. We prospectively investigated the value of 99mTc-Exametazime (99mTc-HMPAO)-labeled leukocytes with regard to specific patterns and for their usefulness in the follow-up of patients with WG. METHODS: The vasculitis group consisted of 8 patients with WG and 2 with idiopathic necrotizing glomerulonephritis (ING). Seven patients with different inflammatory diseases served as controls. Leukocyte labeling with 99mTc-HMPAO was done using a slightly modified Hammersmith protocol. Cell viability after labeling was verified in vivo by the exclusion of early lung and splenic uptake and in vitro by means of propidium iodide and FACS analysis. Static gamma camera images from the head, chest, abdomen, and pelvis were obtained up to 18 hours after injection of approximately 300 MBq 99mTc-HMPAO-labeled leukocytes. Scintigrams were analyzed visually; for semiquantitative analysis ROIs were drawn over the nasal region, the right lung, kidneys, and liver. RESULTS: Increased nasal leukocyte accumulation was found in 7/8 patients with WG and in 2/2 patients with ING. Of 2 patients who had a relapse 6 months later, one presented with, and one without nasal uptake. The kidney/liver ratio was higher in controls (0.24 +/- 0.07 vs. 0.37 +/- 0.11, p < 0.05). Distinct to moderate lung uptake was observed in 2 patients with WG and in one with ING. No correlation was found between scintigraphic results, medication, ANCA status or cretinine levels. CONCLUSION: Nasal leukocyte accumulation is increased in systemic vasculitis, independent of the immunosuppressive treatment and later clinical course. However, this finding is not specific for vasculitis. 99mTc-HMPAO leukocyte scintigraphy failed to indicate or exclude a later relapse and is therefore not suitable as a diagnostic tool in the management of patients with systemic vasculitis.

Adult↗
PubMed2002

Response to vWF-coated beads and soluble p-selectin to characterize apheresis platelets: a comparison of three cell separators.

BACKGROUND: Plateletpheresis technologies differ among various cell separators. Differences in centrifugation force, centrifugation time, and platelet concentration in the platelet concentrate may affect platelet activation and function. STUDY DESIGN AND METHODS: In a three-way crossover design, 12 donors were randomly assigned to three types of cell separators, two continuous flow systems (Amicus DN, Fenwall Division, Baxter and Spectra LRS, Gambro BCT) and one intermittent flow system (MCS+, Haemonetics). The response to vWF-coated beads was determined in the peripheral blood and fresh platelet concentrates to obtain information about the initiating step of platelet aggregation, that is, platelet adhesion. Levels of soluble p-selectin were measured as a marker of platelet activation. RESULTS: Platelet yield and concentration of platelets were higher in platelet concentrates obtained with the Amicus DN than with the Spectra LRS or the MCS+. Maximal aggregation was significantly higher in platelets from the Amicus DN than in platelets from the Spectra LRS or the MCS+. Higher concentrations of soluble p-selectin were seen in platelet concentrates obtained with the Amicus DN than in concentrates from the Spectra LRS or the MCS+, but they did not differ after correction for the number of platelets per component. CONCLUSIONS: Different plateletpheresis procedures induced distinct changes of platelet function. Platelets collected using the Amicus DN retained the strongest adhesion capacity irrespective of their activation.

Adult↗