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Background: Calcific aortic stenosis (AS), the most frequent heart valve disorder in developed countries, leads to the calcification and fibrous thickening of the valve. While several studies have addressed the process of valvular calcification, the molecular pathomechanisms of the extensive matrix remodeling remain unclear. Because inflammation is present in stenotic valves, we hypothesized that the proinflammatory cytokine tumor necrosis factor alpha (TNFalpha) might influence cell proliferation and regulate the expression and activation of matrix metalloproteinases (MMPs)--enzymes that are thought to be involved in calcific AS., Methods: Immunohistochemistry for leukocytes, TNFalpha, MMP-1, and the endogenous MMP inhibitor tissue inhibitor of metalloproteinase (TIMP)-1 was performed on human stenotic (n = 19) and control (n = 8) valves. Primary cultures of human aortic valve myofibroblasts were incubated with and without TNFalpha, and cell proliferation was assessed. The expression and activation of MMP-1 were detected by Western blotting and a specific MMP-1 activity assay., Results: Control valves showed scattered macrophages and low expression of TNFalpha, MMP-1, and TIMP-1. In stenotic valves, leukocyte infiltration and a strong, colocalized expression of TNFalpha and MMP-1 were present, while TIMP-1 remained unchanged. Double-label immunofluorescence localized TNFalpha mainly to macrophages. In cultured human aortic valve myofibroblasts, TNFalpha stimulated proliferation and induced a time-dependent increase in MMP-1 expression and activation, while TIMP-1 remained unchanged., Conclusion: The results indicate that matrix remodeling in calcific AS involves the expression and activation of MMPs. Activated leukocytes, by the secretion of TNFalpha, may stimulate valvular myofibroblasts to proliferate and express MMPs, thus regulating actively the matrix remodeling in calcific AS.

Calcific aortic valve stenosis, the main heart valve disease in the elderly, is based on progressive calcification and fibrous thickening of the valve. Several reports addressed the pathogenesis of tissue calcification in this disorder, but few data exist on the molecular mechanisms of the fibrosis and remodeling of the extracellular matrix. The cytokine "receptor activator of nuclear factor kappa B ligand" (RANKL), is expressed in stenotic aortic valves and involved in valvular calcification during calcific aortic valve stenosis. The present study aimed to assess the influence of RANKL on the molecular mechanisms of connective tissue remodeling. In an established cell culture model of primary human aortic valve myofibroblasts, stimulation with RANKL increased cell proliferation as compared to medium alone. Matrix metalloproteinase (MMP)-1 was detectable time-dependently in conditioned media from RANKL-stimulated cells, but absent in media from control cells. MMP-1 activity was increased by RANKL, as measured by collagenase activity assay. Zymography showed an increase in active MMP-2 in RANKL-stimulated cells. These results support the concept that MMPs are involved in the connective tissue remodeling during calcific aortic valve stenosis. RANKL might regulate this process by promoting cell proliferation and MMP expression and activation.

The family of natriuretic peptides comprises several structurally related 22-53-amino acid peptides, such as atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP), which are vasoactive peptides with vasodilator and diuretic properties and play an important role in cardiovascular homeostasis. The salutary cardiovascular effects of natriuretic peptides suggest that ANP and BNP may have a pathophysiological significance in the cardiac dysfunction of septic patients. We determined plasma levels of the stable N-terminal prohormone forms of ANP (NT-proANP) and BNP (NT-proBNP) as well as troponin I (TNI) as a marker of myocardial cell injury by ELISA methods in 19 septic patients and 19 healthy controls at day one of severe sepsis. Left ventricular ejection fraction (LVEF) was determined on day 1 of severe sepsis by echocardiography. Significantly higher concentrations of NT-proANP were measured in non-survivors (mean = 13415 pmol/l +/- SEM = 4295) and survivors (mean = 7386 pmol/l +/- SEM = 1807) as compared to controls (mean = 1404 pmol/l +/- SEM = 181; p<0.001). Levels of NT-proBNP were also significantly higher in non-survivors (mean = 3439 pmol/l +/- SEM = 1246; p<0.05) and survivors (mean = 1009 pmol/l +/- SEM = 263; p<0.001) as compared to controls (mean = 200 pmol/l +/- SEM = 24) and correlated well with an increase in TNI-levels (r = 0.71; p<0.001). NT-proANP and NT-proBNP may serve as useful laboratory markers to indicate myocardial dysfunction and may help to differentiate between survivors and non-survivors of severe sepsis.

Objective and Design: Non-anticoagulant biological activities, such as anti-inflammatory and anti-apoptotic mechanisms of action, have been suggested for recombinant human activated protein C (rhAPC; drotrecogin alfa (activated)). However, these mechanisms are much less characterized and understood than rhAPC's anticoagulant activity. Aim of the study was to determine the effect of rhAPC on the activity of the pro-inflammatory transcription factor nuclear factor kappa B (NF-kappaB) in mononuclear cells isolated from septic patients and to characterize an effect downstream from NF-kappaB activation, such as the release of the NF-kappaB-controlled chemokine Macrophage Inflammatory Protein-1-alpha (MIP-1-alpha)., Subjects: Peripheral blood was obtained from 13 septic patients and from 8 healthy controls., Methods: Mononuclear cells were isolated by Ficoll-Paque density gradient centrifugation and were incubated with or without rhAPC (10 microg/ml) for 2 h for the measurement of NF-kappaB activity in cell lysates or alternatively for 6 h for the determination of MIP-1-alpha levels in supernatants. NF-kappaB activity was measured by an ELISA-based assay directed against the p50 and the p65 subunit of NF-kappaB., Results: RhAPC, at supra-pharmacological concentration (10 microg/ml), significantly inhibited NF-kappaB activity and the release of MIP-1-alpha ex vivo in isolated mononuclear cells from patients with severe sepsis. In mononuclear cells of healthy subjects, however, rhAPC did not change NF-kappaB activity. Basal NF-kappaB activity early in severe sepsis was not predictive for survival., Conclusions: RhAPC at supra-pharmacological concentration (10 microg/ml) inhibits the activity of NF-kappaB in ex vivo isolated mononuclear cells of septic patients as well as the release of MIP-1-alpha, a proinflammatory chemokine regulated by NF-kappaB. These findings may represent immunomodulatory pathways by which rhAPC exerts specific anti-inflammatory activity in vitro in addition to its known anticoagulant and profibrinolytic activity and should be further investigated in an in vivo setting.

Background and Aim of the Study: Calcific aortic stenosis, the major heart valve disease encountered in the elderly, leads to massive calcium deposition in the valve leaflets that morphologically resembles bone formation. Recent studies have demonstrated the expression of various bone-associated proteins in stenotic valves, suggesting that valvular calcification may be an actively regulated process. Bone sialoprotein (BSP), a non-collagenous bone matrix protein, and bone morphogenetic protein-2 (BMP-2), a member of the transforming growth factor cytokine superfamily, are known to participate in the regulation of bone development and maturation. Their pathogenetic role in calcific aortic stenosis is unknown., Methods: Using an immunoperoxidase technique and antibodies against BSP and BMP-2, the expression of BSP and BMP-2 was examined in 16 human aortic valves with calcific aortic stenosis obtained at valve replacement, and in seven normal autopsy controls without signs of aortic stenosis., Results: By semiquantitative scoring, stenotic valves showed a significantly increased staining of BSP in cells and extracellular matrix as compared to control valves (2.7 +/- 0.1 versus 0.6 +/- 0.2 score units, p <0.001). Marked BMP-2 expression was detected in stenotic valves, mostly in cell-rich areas associated with focal calcium deposits, but no specific staining for BMP-2 was detected in control valves (1.5 +/- 0.2 versus 0.0 +/- 0.0 score units, p <0.001)., Conclusion: These results demonstrate for the first time that BSP and BMP-2 are differentially expressed in normal aortic valves and in aortic stenosis, thereby supporting the concept that valvular calcification might be based on an actively regulated process involving BSP and BMP-2.

Introduction: Radiofrequency ablation produces a localized endomyocardial necrosis that may result in release of biochemical markers reflecting myocardial cell damage, inflammation, and tissue reparation. The aim of this study was to determine the extent of rise and time course of markers of inflammation and tissue reparation in patients undergoing radiofrequency catheter ablation., Methods and Results: Serial blood samples were taken from patients with AV nodal reentrant tachycardia (n = 5), Wolff-Parkinson-White syndrome (n = 3), and atrial flutter (n = 5) undergoing radiofrequency ablation. Blood was taken before ablation (day 0, baseline) and at day 1 and day 120 after ablation. The proinflammatory marker interleukin-6 (IL-6), troponin I (TNI), and myoglobin, as well as matrix metalloproteinase-9 (MMP-9), a marker for myocardial healing, were measured by enzyme-linked immunosorbent assay. Levels of IL-6, TNI, myoglobin, and MMP-9 were significantly elevated on day 1 after ablation compared to baseline levels. Seven of the 13 patients had troponin levels greater than the threshold of significant myocardial damage (>0.1 ng/mL) on day 1. Plasma levels of MMP-9 were still elevated on day 120 compared to values before ablation (P = 0.021)., Conclusion: Markers of inflammation, wound healing, and myocardial damage are increased in patients who undergo radiofrequency ablation. Levels of MMP-9, a marker for myocardial healing and repair, are still elevated 120 days after the procedure, suggesting that radiofrequency ablation induces tissue damage leading to a long-term process of reparation.

Several lines of evidence have implicated activated protein C (APC) to be an endogenous inhibitor of the inflammatory septic cascade. APC may exhibit direct anti-inflammatory properties, independent of its antithrombotic effects. Chemokines influence the interaction of monocytes at the endothelium during infection and sepsis and are involved in the molecular events leading to an adverse and lethal outcome of sepsis. Defining regulatory mechanisms on the monocytic release profile of the proinflammatory C-C chemokines macrophage inflammatory protein-1-alpha (MIP-1-alpha) and monocyte chemoattractant protein-1 (MCP-1) might have therapeutic implications for the treatment of sepsis. We established a monocytic cell model of inflammation by the addition of lipopolysaccharide (LPS) and examined the effect of human APC on LPS-stimulated chemokine release from the monocytic cell line THP-1. We found that human APC in supra-physiological concentrations of 2.5-10 microg/ml inhibited the LPS-induced release of the chemokines MIP-1-alpha and MCP-1, as measured by enzyme-linked immunosorbent assays (ELISA) at 6 up to 24 h. In addition to experiments on THP-1 cells, recombinant human APC in concentrations of 50 ng/ml was found to have an inhibiting effect on the release of MIP-1-alpha from freshly isolated mononuclear cells of septic patients. The ability of APC to decrease the release of the C-C chemokine MIP-1-alpha from the monocytic cell line THP-1 and from human monocytes may identify a novel immunomodulatory pathway by which APC exerts its anti-inflammatory action and may contribute to control the inflammatory response in sepsis., (Copyright 2004 Elsevier Ltd.)

Unlabelled: Anesthetics are known to interfere with the production of inflammatory cytokines. In this study, we investigated the effect of xenon and isoflurane on the lipopolysaccharide (LPS)-induced activation of the nuclear transcription factor (NF)-kappaB and production of tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 in vitro. Whole blood was incubated with LPS in the absence or presence of the either xenon (30 and 60 Vol%) and isoflurane (1 and 2 minimum alveolar anesthetic concentration [MAC]). After 4 h, TNF-alpha and IL-6 were assayed in the supernatant. Involvement of NF-kappaB was investigated using isolated monocytes from the blood samples. Whole-cell lysates were prepared, and binding of the NF-kappaB p50 and p65 subunit to its target DNA were measured with an enzyme-linked immunosorbent assay-based NF-kappaB kit. LPS-induced production of TNF-alpha and IL-6 as well as activation of NF-kappaB were significantly increased in the presence of xenon compared with controls. In contrast, isoflurane inhibited the activation of NF-kappaB, which was associated with a decreased production of TNF-alpha and IL-6. Our results demonstrate that xenon and isoflurane have opposite effects on the LPS-induced production of TNF-alpha and IL-6. Furthermore, xenon increases, whereas isoflurane inhibits the activation of NF-kappaB, providing a possible molecular mechanism for the different effects on monocyte TNF-alpha and IL-6 production., Implications: This study has shown that monocytes respond to lipopolysaccharide (LPS) in the presence of xenon with an increased activation of nuclear transcription factor (NF)-kappaB, whereas isoflurane inhibits LPS-induced activation of NF-kappaB. These findings suggest a possible molecular mechanism for the different effects of both anesthetics on monocyte tumor necrosis factor-alpha and interleukin-6 production.

Calcific aortic stenosis is the main heart valve disease in the elderly, leading to massive focal calcification and thickening of the valve cusps. Matrix metalloproteinases (MMPs) are thought to contribute to this process. Therefore, the study assessed the expression of the gelatinases MMP-2 and MMP-9 and the endogenous tissue inhibitor of metalloproteinase (TIMP)-2 as well as the gelatinolytic activity in normal and stenotic valves. Human tricuspid aortic valves with and without calcific aortic stenosis were studied by immunohistochemistry for MMP-2, MMP-9 and TIMP-2. The gelatinolytic activity in native valve sections was assessed by gelatin in situ zymography with or without addition of the MMP activator p-aminophenymercuric acetate (APMA). Staining intensities for MMP-2 and TIMP-2 were elevated in stenotic valves as compared to controls. Minor staining of MMP-9 was present exclusively in stenotic valves. The morphologic distribution of gelatinolytic activity was comparable to the staining pattern of MMP-2, and since MMP-9 immunostaining demonstrated only a low number of positive cells, the observed gelatinolytic activity is likely due to MMP-2. Gelatinolytic activity was low in normal valves but significantly increased by the MMP activator APMA. In contrast, stenotic valves showed a strong basal gelatinolytic activity that could not be significantly enhanced by APMA suggesting that MMP-2 is present as a latent pro-enzyme in normal valves and activated in stenotic valves. Thus, MMP-2 might be involved in the matrix remodeling during calcific aortic stenosis.

Objective: - Recent studies have suggested that valvular calcification in calcific aortic stenosis (AS) may be actively regulated. "Receptor Activator of Nuclear factor kappaB Ligand" (RANKL) and osteoprotegerin (OPG) are members of a cytokine system involved in bone turnover and vascular calcification. Their role in calcific AS is not known., Methods and Results: - By immunohistochemistry using human aortic valves, RANKL was not expressed at relevant levels in controls but detectable in AS. OPG expression was marked in controls but significantly lower in AS. Areas containing focal calcification exhibited significantly less OPG-positive cells as compared to non-calcified regions. Stimulation with RANKL lead to a significant rise in matrix calcification, nodule formation, alkaline phosphatase activity, expression of the bone-type isoenzyme of alkaline phosphatase, and expression of osteocalcin in cultured human aortic valve myofibroblasts. Moreover, RANKL increased DNA binding of the essential osteoblast transcription factor cbfa-1., Conclusion: - RANKL and OPG are differentially expressed in calcific AS. In cultured human aortic valve myofibroblasts, RANKL promotes matrix calcification and induces the expression of osteoblast-associated genes, indicating a transition towards an osteogenic phenotype. These results suggest that the RANKL-OPG pathway may regulate valvular calcification in calcific AS?

Radiofrequency (RF) catheter ablation has been shown to be highly effective in the treatment of supraventricular tachycardias. Atrial natriuretic peptide (ANP) and brain natriuretic peptide (B-type natriuretic peptide; BNP) are secreted by the heart mainly in response to myocardial stretch induced by volume load. The aim of the present study was to determine the time course of the N-terminal prohormone forms of ANP (NT-proANP) and BNP (NT-proBNP) in patients undergoing radiofrequency (RF) catheter ablation for paroxysmal supraventricular tachycardias. Serial blood samples were taken from 13 patients with symptomatic paroxysmal supraventricular tachycardias undergoing RF ablation and from 13 age- and gender-matched healthy controls. Blood was taken before ablation (day 0, baseline), and at day one and day 120 after ablation. Levels of NT-proANP were significantly higher before RF ablation (4862+/-726 pmol/l) as compared to day one (2021+/-220 pmol/l) and day 120 after RF ablation (2470+/-349 pmol/l) (with p<0.01 on day one and p<0.05 on day 120; n=13). The size of the left atrium decreased from 41.0+/-5.5 mm before ablation to 34.9+/-5.9 mm (n=13; p<0.05) on day 120 as measured by M-mode echocardiography. Levels of NT-proBNP showed comparable values before and on day one and day 120 after ablation and were not significantly elevated as compared to healthy controls. NT-proANP levels are increased in patients presenting with paroxysmal supraventricular tachycardias and decrease one day after radiofrequency catheter ablation, possibly reflecting a transient reduction of ANP secretion from injured myocardial cells. Lower NT-proANP levels in the long-term time course may result from reduction of atrial volume load and reconstitution of atrial architecture after successful treatment of supraventricular tachycardias. NT-proANP may serve as a useful laboratory marker to describe the long-term interventional success after RF ablation.

Inflammation within coronary plaques may cause an acute coronary syndrome by promoting rupture and erosion. It was the aim of this study to examine whether markers of inflammation derive from a cardiac or extracardiac source and how their levels develop over time. Blood samples were taken from patients with acute coronary syndromes (ACS) with proven atherosclerotic lesion(s) of the left coronary artery (n=13) and from control patients without coronary artery disease (n=13). Blood was taken from the femoral vein and the coronary sinus vein before and after coronary angioplasty (day 0) and on days 1 and 120. Levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), interleukin-1-receptor antagonist (IL-1 ra) and soluble CD40 ligand (sCD40L) were higher in ACS patients as compared to controls and remained elevated up to day 120. In the long-term time course these markers of inflammation and plaque remodeling slightly decreased in ACS patients. There were no statistically significant differences detectable in the levels of TNF-alpha, IL-6, IL-1 beta, IL-10, IL-1 ra, sCD40L and monocyte chemoattractant protein-1 (MCP-1) in the blood of ACS patients taken from a cardiac source as compared to an extracardiac source (coronary sinus vs. femoral vein). This study demonstrates the importance of a systemic inflammatory condition in patients with ACS, in whom markers of inflammation are increased as compared to controls. During long-term follow-up the pro-inflammatory activity remains elevated in ACS patients, supporting the concept of a systemic rather than a local vascular inflammation contributing to the development of atherosclerosis.

Calcific aortic valve stenosis (AS), the main heart valve disease in the elderly, is characterized by extensive remodeling of the extracellular matrix. Matrix metalloproteinases (MMPs) are upregulated in calcific AS and might modulate matrix remodeling. The regulatory mechanisms are unclear. As recent studies have suggested that calcific AS might result from an inflammatory process involving leukocyte invasion and activation, the present study aimed to elucidate the role of the pro-inflammatory cytokine interleukin (IL)-1 beta on MMP expression and cell proliferation in human aortic valves. Immunohistochemistry for leukocytes, IL-1 beta and MMP-1 was performed on aortic valves with (n=6) and without (n=6) calcification obtained at valve replacement or autopsy. Stenotic valves showed marked leukocyte infiltration and associated expression of IL-1 beta and MMP-1. In control valves only scattered leukocytes, low staining for MMP-1 and no staining for IL-1 beta were present. Double-label immunostaining localized IL-1 beta expression mainly to leukocytes and MMP-1 expression to myofibroblasts. Stimulation of cultured human aortic valve myofibroblasts with IL-1 beta lead to a time-dependently increased expression of MMP-1 and MMP-2 by Western blotting and zymography, whereas MMP-9 remained unchanged. Cell proliferation was increased by IL-1 beta as determined by bromodesoxyuridine incorporation. Thus, IL-1 beta may regulate remodeling of the extracellular matrix in calcific AS.

Background and Aim of the Study: Non-rheumatic, calcific aortic stenosis (AS) is the most prevalent heart valve disease in the elderly. It is based on a chronic inflammatory process with infiltration and activation of leukocytes, and a rise in systemic inflammatory markers. An association with Chlamydia pneumoniae infection has been discussed, but previous studies have yielded divergent results., Methods: Tricuspid aortic valves with calcific AS were obtained from patients undergoing aortic valve replacement. Control valves from patients matched for age and cardiovascular risk factors were obtained at autopsy. Immunohistochemistry was performed using monoclonal antibodies directed against C. pneumoniae and against leukocyte common antigen. Cultured HEp-2 cells infected with C. pneumoniae were used as positive controls., Results: Positive immunostaining for C. pneumoniae was demonstrated in 12 of 14 (86%) stenotic valves and in six of nine (67%) control valves. Immunostained cells were located mainly in cell- and leukocyte-rich areas. Although stenotic valves showed a higher staining intensity as assessed by semiquantitative scoring (1.8 +/- 0.4 versus 0.8 +/- 0.2 units, p < 0.05), there was no statistically significant difference between stenotic and control valves regarding the presence of C. pneumoniae (p = 0.90)., Conclusion: Positive immunostaining for C. pneumoniae was not associated with the presence of calcific AS. As in previous serologic and molecular biology studies, a high prevalence of C. pneumoniae in the adult population was demonstrated, irrespective of heart valve disease. Thus, C. pneumoniae is most likely not involved in the pathogenesis of calcific aortic stenosis.

Objectives: To evaluate clinical and laboratory effects of the administration of recombinant human activated protein C (rhAPC) in the treatment of a 25-year-old patient with septic shock and multiple organ failure secondary to perinephritic abscesses., Interventions: Intravenous administration of rhAPC-or drotrecogin alfa (activated)-(24 mcg/kg/h) for a total of 80 h as an adjunct to antimicrobial therapy, mechanical ventilation, hemodynamic support, hemodiafiltration and surgical intervention., Measurements and Main Results: The administration of rhAPC was associated with a rapid recovery of the patient's clinical condition reflected by decreasing Sepsis-related Organ Failure Assessment (SOFA) scores. Laboratory parameters monitoring inflammation and coagulopathy improved during the treatment. No drug-related adverse events were noted., Conclusions: RhAPC has been observed to have anticoagulant, anti-inflammatory and profibrinolytic properties in vitro and in vivo. This report describes the effects of rhAPC administration on standard laboratory parameters indicating that no single laboratory parameter exists that is capable of monitoring the effects of rhAPC on the coagulation cascade and the clinical course of sepsis. This description of a patient suffering from sepsis-induced multiple organ failure may illustrate a possible beneficial effect of rhAPC on the course of coagulopathy and systemic inflammatory response and provides evidence for rhAPC complementing standard intensive care therapy in severe sepsis.

Matrix metalloproteinase (MMP)-2 and MMP-9 are believed to play a pathophysiologic role in acute myocardial infarction (MI). The time course of their plasma concentrations in correlation with the extent of myocardial damage is unclear. In a prospective study, 20 patients with proven acute MI underwent successful reperfusion within 6 h after the onset of symptoms. The patients were divided into two groups according to the size of their MI, i.e. large or moderate MI. Plasma concentrations of MMP-2, MMP-9 and tissue inhibitor of metalloproteinase (TIMP)-1 were determined on admission, and after 24 h, 48 h, 1 week, 4 weeks, 3 months and 6 months. MMP-2 levels remained unchanged over time in both groups. The plasma concentration of MMP-9 was elevated on admission in patients with large MI versus moderate MI (195 +/- 190 versus 78 +/- 63 ng/ml, p < 0.01) as determined by left ventriculography, and returned to baseline (18 +/- 16 ng/ml) by 1 week after MI. TIMP-1 levels rose slowly in patients with large MI and returned to baseline at 6 months. The ratio of MMP-9 to TIMP-1 was significantly increased on admission in both groups and returned to baseline at 48 h. These data suggest that MMP-9 might play a pathophysiologic role during the early phase of acute MI., (Copyright 2003 S. Karger AG, Basel)

The activated protein C (APC) pathway has been suggested to be a common link between coagulation and inflammation. APC may function to restore hemostasis via modulation of cytokine expression. We investigated the effect of APC on the endothelial expression of monocyte chemoattractant protein-1 (MCP-1), a chemokine that is controlled by the activation of central proinflammatory transcription factors, such as nuclear factor-kappa B (NF-kappaB). We found that human APC (2.5-10 micro g/ml) upregulated the amount of MCP-1-mRNA in human umbilical vein endothelial cells (HUVEC) and caused a time- and dose-dependent increase in MCP-1 protein production (p <0.001 for APC 2.5 micro g/ml at 4 up to 24 h). In this cell culture model MCP-1 induced an improvement of cell migration and wound repair after injury to endothelial monolayers. After stimulation of MCP-1-mRNA-transcription with TNF-alpha (0.1-1 ng/ml), HUVEC's were washed and an inhibitor of gene transcription, Actinomycin D (1 micro g/ml), was added in the presence or absence of APC. HUVEC's receiving APC contained more MCP-1-mRNA than controls after one hour and up to eight hours suggesting an inhibitory effect of APC on MCP-1-mRNA degradation (with APC: 753 +/- 56 atto mol of MCP-1-mRNA per ml of cell lysate vs. 263 +/- 60 atto mol/ml without APC at t =4 h; p <0.001). Electrophoretic mobility shift assays revealed that APC attenuated NF-kappaB DNA-binding capacity implying that NF-kappaB may not be involved in the upregulatory effect of APC on MCP-1 production. The ability of APC to upregulate the production of MCP-1, most likely by increasing the stability of MCP-1-mRNA rather than by transcriptional activation via NF-B, identifies a novel immunomodulatory pathway, by which APC may control the local inflammatory reaction, thereby initiating wound repair and modulating the extent of endothelial injury.