Levels of oxidized low-density lipoproteins are increased in patients with severe sepsis.

BACKGROUND: It was hypothesized that the inflammatory response of patients with severe sepsis may result in changes of plasma levels of oxidized low-density lipoproteins (ox-LDLs) and that drotrecogin alpha (activated) (DAA) (Xigris, Eli Lilly and Company [Indiana 46285, USA]) may influence ox-LDL levels. MATERIALS AND METHODS: The ox-LDL levels were measured in severe septic patients on day 1, 4, and 7 of severe sepsis. Patients were treated either with or without DAA. RESULTS: The ox-LDL levels increased significantly (P < .05) from day 1 to day 7 (day 1, mean +/- SEM, 25.4 +/- 1.8 U/L; day 4, mean +/- SEM, 34.3 +/- 2.1 U/L; day 7, mean +/- SEM, 38.3 +/- 2.1 U/L) in all patients (n = 68). The ox-LDL levels increased significantly from day 1 to day 7 both in patients treated with (n = 31) and without DAA (n = 37) (P < .001) (DAA-group: day 1, mean +/- SEM, 24.4 +/- 2.8 U/L; day 4, mean +/- SEM, 35.5 +/- 2.9 U/L; day 7, mean +/- SEM, 40.7 +/- 3.2 U/L) (control group: day 1, mean +/- SEM, 26.3 +/- 2.8 U/L; day 4, mean +/- SEM, 33.2 +/- 2.9 U/L; day 7, mean +/- SEM, 36.4 +/- 2.9 U/L). No significant differences of ox-LDL levels were observed between both groups at any point of time (P > .05). CONCLUSIONS: The ox-LDL concentrations increase significantly during the first week of severe sepsis and are not affected by administration of drotrecogin alpha (activated) (Xigris).

Time-course of neopterin levels in patients suffering from severe sepsis treated with and without Drotrecogin-alpha (activated).

Neopterin is secreted by activated monocytes/macrophages upon stimulation with interferon-gamma. The release of this pro-inflammatory mediator permits the activation status of cell-mediated immune system to be examined. We assayed neopterin plasma concentrations in septic patients under treatment with (n=10) and without Drotrecogin-alpha (activated) (n=10) on d 1 and 6 of severe sepsis. In septic patients treated with Drotrecogin-alpha (activated), neopterin levels decreased significantly (p=0.027) from d 1 (baseline) (mean 140.8 nmol/l, +/-standard error of mean (SEM) 106.2) to d 6 (mean 68.9 nmol/l, +/-SEM 46.4). In patients not treated with Drotrecogin-alpha (activated) there was no significant (p=0.96) decrease of neopterin levels from d 1 (mean 147.8 nmol/l, +/-SEM 58.4) to d 6 (mean 139.7 nmol/l, +/-SEM 52.6). Furthermore, neopterin levels showed significant correlations with bilirubin in all patient groups on d 1 of severe sepsis (range of correlation coefficient, r: 0.69-0.88; p<0.05). Neopterin levels correlated significantly with creatinine with regard to all patient groups (range of correlation coefficient, r: 0.73-0.92; p<0.05). In conclusion, Drotrecogin- alpha (activated) was associated with a significant decrease of neopterin plasma levels in septic patients. Neopterin concentrations appear to depend on renal function and enterohepatic circulation.

Matrix-metalloproteinases and their inhibitors are elevated in severe sepsis: prognostic value of TIMP-1 in severe sepsis.

The enzyme group of matrix metalloproteinases (MMPs) and their inhibitors, so-called tissue inhibitors of matrix-metalloproteinases (TIMPs), are crucial mediators responsible for wound repair after parenchymal damage. Little is known about the role of MMPs and TIMPs in severe sepsis. The aim of the present study was therefore to investigate their levels in patients with severe sepsis and to examine their association with prognosis. MMP-2, MMP-9, TIMP-1, TIMP-2 and interleukin-6 (IL-6) plasma levels were measured by ELISA methods in 37 patients on day 1 of severe sepsis. 37 healthy volunteers served as controls. Levels of MMP-9, TIMP-1, TIMP-2 and IL-6 in septic patients were significantly higher compared to healthy controls (p<0.001), whereas MMP-2 levels were not different in patients and controls. TIMP-1 levels were significantly higher in non-survivors (4675+/-435 ng/ml, mean+/-SEM) compared to survivors of severe sepsis (3201+/-249 ng/ml; p<0.01). Septic patients with TIMP-1 values >3200 ng/ml were 4.5 times more likely to die than patients with lower values (RR = 4.5; 95% CI 1.14-17.6, p = 0.014). Our results indicate that MMP-9, TIMP-2 and TIMP-1 are elevated in severe sepsis. Furthermore, TIMP-1 may serve as a useful laboratory marker to predict the clinical outcome of patients presenting with severe sepsis.

Increased plasma levels of NT-proANP and NT-proBNP as markers of cardiac dysfunction in septic patients.

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.

Modulation of myosin filament activation by telokin in smooth muscle liberation of myosin kinase and phosphatase from supramolecular complexes.

The mechanism of telokin action on reversible phosphorylation of turkey gizzard myosin was investigated using a native-like filamentous myosin. This myosin contained endogenous calmodulin (CaM) and myosin light chain kinase (MLCK) at a molar ratio to myosin of about 1 to 40 or less depending on the initial extractions conditions. These levels were sufficient to fully phosphorylate myosin within 20-40 s or less after addition of [gamma-32P]ATP, but when the ATP was depleted, they became dephosphorylated indicating the presence of myosin light chain phosphatase (MLCP). Addition of telokin at the 1 to 1 or higher molar ratio to myosin caused a three- to five-fold inhibition of the initial phosphorylation rates (without reduction of the overall extent of phosphorylation) and produced a similar increase in the rate of dephosphorylation. The inhibition was also observed for myosin filaments free of MLCK and CaM together with constitutively active MLCKs produced by digestion, or by expression of a truncated mammalian kinase as well as for the wild-type enzyme. Thus, neither N- nor C-terminal of MLCK was necessary for interaction of myosin with telokin and the inhibition resulted from telokin-induced change of myosin head configuration within the filament that prevented their ordered, paracrystaline-like, aggregation. Sedimentation of the filamentous myosin in glycerol gradients showed that this change made the filaments less compact and facilitated release of the endogenous MLCK/CaM complex. For a mixture of the filaments with or without the complex, the configuration change resulted in an increase of the phosphorylation rate but not in its inhibition. The increase of the rate resulting from the liberation of the complex was also observed in mixtures of the filamentous myosin with added isolated regulatory light chain (ReLC) or soluble myosin head subfragment. This observation reinforces the above conclusions. The acceleration of the MLCP activity by telokin was shown to result from dissociation of its catalytic subunit from a MLCK/MLCP complex bound to the filamentous myosin. Analogous desensitizing effects of telokin were also demonstrated for the contraction and relaxation cycle of Triton-skinned fibers from guinea pig Teania coli. Taken together, our results indicate that telokin acted as an effective modulator or chaperone of the myosin filament and a scheme for its action in smooth muscle was proposed.

Markers of myocardial damage, tissue healing, and inflammation after radiofrequency catheter ablation of atrial tachyarrhythmias.

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.

Glucose increases endothelial-dependent superoxide formation in coronary arteries by NAD(P)H oxidase activation: attenuation by the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor atorvastatin.

Increased vascular superoxide anion (O(2)(-)) formation is essentially involved in the pathophysiology of atherosclerosis. Chronic hyperglycemia induces endothelial dysfunction, probably due to increased formation of reactive oxygen intermediates. However, little is known about the localization, modulators, and molecular mechanisms of vascular O(2)(-) formation during hyperglycemia. In porcine coronary segments, high glucose significantly increased O(2)(-) formation (1,703.5 +/- 394.9 vs. 834.1 +/- 91.7 units/mg for control, n = 64, P < 0.05; measured by lucigenin-enhanced chemiluminescence). This effect was completely blocked after removal of the endothelium. Coincubation with 10 micromol/l atorvastatin, a lipophilic inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme A reductase, attenuated basal and glucose-induced O(2)(-) formation (328.1 +/- 46.5 and 332.8 +/- 50.3 units/mg, P < 0.05 vs. without atorvastatin). Incubation with mevalonic acid reversed this effect. High glucose increased mRNA expression of the oxidase subunit p22(phox), which was blocked by 10 micromol/l atorvastatin, whereas expression of gp91(phox) was unchanged. In conclusion, glucose-induced increase of vascular O(2)(-) formation is endothelium dependent and is probably mediated by increased p22(phox) subunit expression. Beneficial effects of statins in diabetic patients may be explained in part by attenuation of vascular O(2)(-) formation independent of lipid lowering.