320 resultados para Myeloperoxidase (MPO)


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Decreased survival in patients with cystic fibrosis has been related to FEV1, BMI, and infection with Burkholderia cepacia complex (BCC). We have assessed the relationship of blood, sputum, and urine inflammatory markers to lung function, BMI, colonization with B cenocepacia (Bc), and patient survival. Thirty-nine stable cystic fibrosis (CF) patients (10 with Bc) were enrolled in a study to determine the effect of alpha-1-antitrypsin on airways inflammation. Pre-treatment measurements were used in this study. Demographics, sputum microbiology, heart rate, oxygen saturation, lung function were recorded. Blood samples were obtained for white blood count (WBC), C-Reactive Protein (CRP), and plasma neutrophil elastase/AAT complexes (pNEC). Neutrophil elastase (NE), neutrophil elastase/AAT complexes (sNEC), interleukin-8 (IL-8), TNF-receptor 1 (sTNFr), and myeloperoxidase (MPO) were measured in sputum and urinary desmosine concentration determined. Patients with Bc had significantly higher levels of pNEC, 332?±?91.4 ng/ml (mean?±?SEM) versus 106?±?18.2 ng/ml (P?=?0.0005) and sNEC, 369?±?76.6 ng/ml versus 197?±?36.0 ng/ml compared to those who were not. Five deaths were reported at the end of 1 year, (four with Bc) (P?=?0.011). Patients who subsequently died had significantly lower lung function FEV1, 1.2?±?0.2 L versus 2.0?±?0.1 L (P?=?0.03) and FVC, 2?±?0.3 L versus 3.1?±?0.2 L (P?=?0.01), compared to those that survived. There was significantly higher NE activity, 3.6?±?1.6 U/ml versus 1.5?±?0.6 U/ml (P?=?0.03), pNEC, 274?±?99 ng/ml versus 142?±?30 ng/ml (P?=?0.05), MPO, 163?±?62 mcg/ml versus 54?±?6.9 mcg/ml (P?=?0.03), and urinary desmosines 108?±?19.9 pM/mg creatinine versus 51.1?±?3.3 pM/mg creatinine (P?=?0.001), in those patients who subsequently died compared to those that survived. These data suggest there is increased neutrophil degranulation in patients infected with Bc and these patients have a poor outcome.

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Several authors have shown that neutrophil generation of reactive oxygen species (ROS) declines with advancing age. Similar changes have also been suggested in monocytes. In both cases alterations in second messenger activity have been implicated as the most likely explanation for these observations. The aim of this study was to investigate the effect of age on phagocyte ROS generation, stimulated by the direct activation of protein kinase C (PKC). Venous blood was drawn from normal healthy subjects, cells were separated on a double density gradient into mononuclear and polymorphonuclear (pmn) cells. Phorbol myristate acetate (PMA) was employed as a cell stimulus. Superoxide generation was measured by cytochrome c reduction and myeloperoxidase (MPO) products by measurement of peak luminol chemiluminescence (CL). Fifty-eight subjects, 25 males and 33 females, were studied, median age 49 years (range 26-88 years). Polymorphonuclear cell superoxide generation was significantly higher in males and there was a trend towards higher pmn MPO product generation in males. Using Spearman's ranked correlation coefficient, monocyte superoxide generation was negatively correlated with age (r = -0.473, P <0.001). No changes in the generation of MPO products was found. There were also trends towards a negative correlation of pmn cytochrome c reduction and peak luminol CL with age in males but not females. Since PMA directly activates protein kinase C, reduced monocyte superoxide generation with increasing age appears to be related to alterations in the ROS generating system downstream of the cell receptor. Impaired monocyte superoxide generation may have implications for non-specific defence against certain infections and early tumour growth in the elderly. Factors underlying these changes in monocyte function therefore require further study.

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Antibodies to neutrophil cytoplasmic antigens (ANCA) are good serological markers for patients with mainly vasculitic conditions. Two main types of ANCAs have been detected, the first termed cytoplasmic antineutrophil cytoplasmic antibody (cANCA) are mainly associated with patients with Wegener's granulomatosis, the other termed perinuclear antineutrophil cytoplasmic antibody (pANCA) are mainly associated with patients with renal vasculitis, rheumatic and collagen disorders. These antibodies are against various constituents of neutrophil granules. In patients with myelodysplasia, defects in normal granulocyte development are seen. We report a series of twelve patients with myelodysplasia of whom at least four showed a low titre and one a high titre of pANCA. Two of these patients also had demonstrable activity against myeloperoxidase (MPO). None of these patients had any evidence of systemic or cutaneous vasculitis or of any autoimmune disorder. There was no pANCA positivity in an age matched control group.

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The role of hydrogen sulfide (H2 S) in inflammation remains unclear with both pro- and anti-inflammatory actions of this gas described. We have now assessed the effect of GYY4137 (a slow-releasing H2 S donor) on lipopolysaccharide (LPS)-evoked release of inflammatory mediators from human synoviocytes (HFLS) and articular chondrocytes (HAC) in vitro. We have also examined the effect of GYY4137 in a complete Freund's adjuvant (CFA) model of acute joint inflammation in the mouse. GYY4137 (0.1-0.5 mM) decreased LPS-induced production of nitrite (NO2 (-) ), PGE2 , TNF-a and IL-6 from HFLS and HAC, reduced the levels and catalytic activity of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) and reduced LPS-induced NF-?B activation in vitro. Using recombinant human enzymes, GYY4137 inhibited the activity of COX-2, iNOS and TNF-a converting enzyme (TACE). In the CFA-treated mouse, GYY4137 (50 mg/kg, i.p.) injected 1 hr prior to CFA increased knee joint swelling while an anti-inflammatory effect, as demonstrated by reduced synovial fluid myeloperoxidase (MPO) and N-acetyl-ß-D-glucosaminidase (NAG) activity and decreased TNF-a, IL-1ß, IL-6 and IL-8 concentration, was apparent when GYY4137 was injected 6 hrs after CFA. GYY4137 was also anti-inflammatory when given 18 hrs after CFA. Thus, although GYY4137 consistently reduced the generation of pro-inflammatory mediators from human joint cells in vitro, its effect on acute joint inflammation in vivo depended on the timing of administration.

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Activated neutrophils generate the potent oxidant hypochlorous acid (HOCl) from the enzyme myeloperoxidase (MPO). A proposed bio-marker for MPO-derived HOCl in vivo is 3-chlorotyrosine, elevated levels of which have been measured in several human inflammatory pathologies. However, it is unlikely that HOCl is produced as the sole oxidant at sites of chronic inflammation as other reactive species are also produced during the inflammatory response. The work presented shows that free and protein bound 3-chlorotyrosine is lost upon addition of the pro-inflammatory oxidants, HOCl, peroxynitrite, and acidified nitrite. Furthermore, incubation of 3-chlorotyrosine with activated RAW264.7 macrophages or neutrophil-like HL-60 cells resulted in significant loss of 3-chlorotyrosine. Therefore, at sites of chronic inflammation where there is concomitant ONOO- and HOCl formation, it is possible measurement of 3-chlorotyrosine may represent an underestimate of the true extent of tyrosine chlorination. This finding could account for some of the discrepancies reported between 3-chlorotyrosine levels in tissues in the literature. (c) 2008 Elsevier Inc. All rights reserved.

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Hydroquinone (HQ) is an environmental contaminant which causes immune toxicity. In this study, the effects of exposure to low doses of HQ on neutrophil mobilization into the LPS-inflamed lung were investigated. Male Swiss mice were exposed to aerosolized vehicle (control) or 12.5, 25 or 50 ppm HQ (1 h/day for 5 days). One hour later, oxidative burst, cell cycle. DNA fragmentation and adhesion molecules expressions in circulating neutrophils were determined by flow cytometry, and plasma malondialdehyde (MDA) levels were measured by HPLC. Also, 1 h later the last exposures, inflammation was induced by LPS inhalation (0.1 mg/ml/10 min) and 3 h later, the numbers of leukocytes in peripheral blood and in the bronchoalveolar lavage fluid (BALF) were determined using a Neubauer chamber and stained smears; adhesion molecules expressed on lung microvessel endothelial cells were quantified by immunohistochemistry; myeloperoxidase (MPO) activity was measured in the lung tissue by colorimetric assay; and cytokines in the BALF were determined by ELISA. In vivo HQ exposure augmented plasma MDA levels and oxidative activity of neutrophils, but did not cause alterations in cell cycle and DNA fragmentation. Under these conditions, the number of circulating leukocytes was not altered, but HQ exposure reduced LPS-induced neutrophil migration into the alveolar space, as these cells remained in the lung tissue. The impaired neutrophil migration into BALF may not be dependent on reduced cytokines secretions in the BALF and lung endothelial adhesion molecules expressions. However, HQ exposure increased the expression of beta(2) and beta(3) integrins and platelet-endothelial cell adhesion molecule-1 (PECAM-1) in neutrophils, which were not further enhanced by fMLP in vitro stimulation, indicating that HQ exposure activates circulating neutrophils, impairing further stimulatory responses. Therefore, it has been shown, for the first time, that neutrophils are target of lower levels of in vivo HQ exposure, which may be considered in host defense in infectious diseases. (C) 2011 Elsevier Ireland Ltd. All rights reserved.

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This work explored the role of inhibition of cyclooxygenases (COXs) in modulating the inflammatory response triggered by acute kidney injury. C57Bl/6 mice were used. Animals were treated or not with indomethacin (IMT) prior to injury (days -1 and 0). Animals were subjected to 45 min of renal pedicle occlusion and sacrificed at 24 h after reperfusion. Serum creatinine and blood urea nitrogen, reactive oxygen species (ROS), kidney myeloperoxidase (MPO) activity, and prostaglandin E2 (PGE(2)) levels were analyzed. Tumor necrosis factor (TNF)-alpha, t-bet, interleukin (IL)-10, IL-1 beta, heme oxygenase (HO)-1, and prostaglandin E synthase (PGES) messenger RNA (mRNA) were studied. Cytokines were quantified in serum. IMT-treated animals presented better renal function with less acute tubular necrosis and reduced ROS and MPO production. Moreover, the treatment was associated with lower expression of TNF-alpha, PGE(2), PGES, and t-bet and upregulation of HO-1 and IL-10. This profile was mirrored in serum, where inhibition of COXs significantly decreased interferon (IFN)-gamma, TNF-alpha, and IL-12 p70 and upregulated IL-10. COXs seem to play an important role in renal ischemia and reperfusion injury, involving the secretion of pro-inflammatory cytokines, activation of neutrophils, and ROS production. Inhibition of COX pathway is intrinsically involved with cytoprotection.

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Apocynin, a methoxy-substituted catechol (4-hydroxy-3-methoxyacetophenone), originally extracted from the roots of Picrorhiza kurroa, has been extensively used as a non-toxic inhibitor of the multienzymatic complex NADPH oxidase. We discovered that the analogous methoxy-substituted catechol, 4-Fluoro-2-methoxyphenol (F-apocynin), in which the acetyl group present in apocynin was changed to a fluorine atom, was significantly more potent as an inhibitor of NADPH oxidase activity, myeloperoxidase (MPO) chlorinating activity and phagocytosis of microorganisms by neutrophils; it was also as potent as apocynin in inhibiting tumor necrosis factor-alpha (TNF alpha) release by peripheral blood mononuclear cells. We attribute the increased potency of F-apocynin to its increased lipophilicity, which could facilitate the passage of the drug through the cell membrane. The inhibition of MPO chlorination activity, phagocytosis and TNF alpha release shows that apocynin and F-apocynin actions are not restricted to reactive oxygen species inhibition, but further studies are needed to clarify if these mechanisms are related. Like apocynin, F-apocynin did not show cell toxicity, and is a strong candidate for use in the treatment of inflammatory diseases. (C) 2011 Elsevier B.V. All rights reserved.

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Chronic chagasic cardiac patients are exposed to oxidative stress that apparently contributes to disease progression. Benznidazole (BZN) is the main drug used for the treatment of chagasic patients and its action involves the generation of reactive species. 41 patients with Chagas` heart disease were selected and biomarkers of oxidative stress were measured before and after 2 months of BZN treatment (5 mg/kg/day) and the subsequent antioxidant supplementation with vitamin E (800 UI/day) and C (500 mg/day) during 6 months. Patients were classified according to the modified Los Andes clinical hemodynamic classification in groups IA, IB, II and III, and the activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione S-transferase (GST) and glutathione reductase (GR), as well as the contents of reduced glutathione (GSH), thiobarbituric acid reactive species (TBARS), protein carbonyl (PC), vitamin E and C and nitric oxide (NO), myeloperoxidase (MPO) and adenosine deaminase (ADA) activities were measured in their blood. Excepting in group III, after BZN treatment SOD, CAT, GPx and GST activities as well as PC levels were enhanced while vitamin E levels were decreased in these groups. After antioxidant supplementation the activities of SOD, GPx and GR were decreased whereas PC, TBARS, NO, and GSH levels were decreased. In conclusion, BZN treatment promoted an oxidative insult in such patients while the antioxidant supplementation was able to attenuate this effect by increasing vitamin E levels, decreasing PC and TBARS levels, inhibiting SOD, GPx and GR activities as well as inflammatory markers, mainly in stages with less cardiac involvement. (C) 2009 Elsevier Ireland Ltd. All rights reserved.

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Background
Intervention of the biliary system is frequently done in patients with obstructive jaundice and is associated with significant morbidity and mortality. The pathogenesis is unknown.
Materials and methods
A rat model of bile duct ligation (BDL) for 2 weeks was established in which biliary intervention was feasible by injection of normal saline through an indwelling catheter in the bile ducts. Plasma levels of C-C chemokine MCP-1 and C-X-C chemokine MIP-2 were measured by using ELISA. Blood monocytes, Kupffer cells, and neutrophils in the liver were characterized with antibodies to ED1, ED2, and myeloperoxidase (MPO). Lipid peroxidation was measured by malondialdehyde contents and apoptosis by TUNEL stain of the liver.
Results
Biliary intervention resulted in an increase of plasma MCP-1 and MIP-2 proteins by 1 h, which declined to normal level by 3 h in both sham and BDL rats. The levels in BDL rats were significantly higher than in sham at most points. There was a transient increase of ED1- and ED2-positive cells and MPO-staining cells in sham rat liver by 1 h after intervention. ED2-positive cells increased significantly by 1 h, while ED1- and MPO-positive cells decreased, yet insignificantly after intervention in BDL rats. The cell counts in BDL were constantly higher than in sham. Malondialdehyde increased precipitously in BDL by 3 h and was significantly higher than in sham throughout the study period. Parenchymal liver injury, manifested by elevated ALT, as well as apoptosis and necrosis of liver cells, was significantly increased in BDL rats, but not in sham rats.
Conclusion
Biliary intervention augments chemokine expression, precipitates lipid peroxidation, and aggravates liver injury in cholestatic rats.

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The effects of estrogen and ovariectomy on indexes of muscle damage after 2 h of complete hindlimb ischemia and 2 h of reperfusion were investigated in female Sprague-Dawley rats. The rats were assigned to one of three experimental groups: ovariectomized with a 17-estradiol pellet implant (OE), ovariectomized with a placebo pellet implant (OP), or control with intact ovaries (R). It was hypothesized that following ischemia-reperfusion (I/R), muscle damage indexes [serum creatine kinase (CK) activity, calpain-like activity, inflammatory cell infiltration, and markers of lipid peroxidation (thiobarbituric-reactive substances)] would be lower in the OE and R rats compared with the OP rats due to the protective effects of estrogen. Serum CK activity following I/R was greater (P < 0.01) in the R rats vs. OP rats and similar in the OP and OE rats. Calpain-like activity was greatest in the R rats (P < 0.01) and similar in the OP and OE rats. Neutrophil infiltration was assessed using the myeloperoxidase (MPO) assay and immunohistochemical staining for CD43-positive (CD43+) cells. MPO activity was lower (P < 0.05) in the OE rats compared with any other group and similar in the OP and R rats. The number of CD43+ cells was greater (P < 0.01) in the OP rats compared with the OE and R rats and similar in the OE and R rats. The OE rats had lower (P < 0.05) thiobarbituric-reactive substance content following I/R compared with the R and OP rats. Indexes of muscle damage were consistently attenuated in the OE rats but not in the R rats. A 10-fold difference in serum estrogen content may mediate this. Surprisingly, serum CK activity and muscle calpain-like activity were lower (P < 0.05) in the OP rats compared with the R rats. Increases in serum insulin-like growth factor-1 content (P < 0.05) due to ovariectomy were hypothesized to account for this finding. Thus both ovariectomy and estrogen supplementation have differential effects on indexes of I/R muscle damage.

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BACKGROUND: 50% to 60% of the people who have recovered from the first episode of depression experience a relapse. The immune system of the people suffering from depression is in a permanent state of pathological pro-inflammatory readiness. There are some reports that depressive episodes cause sensitization of immune-inflammatory pathways and that staing of depression (e.g. number of depressive episodes) is correlated with immune-inflammatory markers. The main objective of the study was to delineate whether recurrent major depression (rDD) is characterized by alterations in selected immune-inflammatory biomarkers as compared with first episode of depression (ED-I), i.e. expression of mRNA and enzymatic activity of manganese superoxide dismutase (MnSOD, SOD-2), myeloperoxidase (MPO), inducible nitric oxide synthase (iNOS, NOS-2), and cyclooxygenase-2 (COX-2). METHODS: The study was carried out in a group of 131 patients: ED-I group - 42 patients, rDD group - 89 patients. Depression severity was assessed with the 17-item Hamilton Depression Rating Scale (HDRS). The number of depression episodes and the disease duration periods were recorded in each patient. For the patients, HDRS was administered at admission during the symptomatic phase, which would generally be either before or shortly after modification of the previous antidepressant drug regimen. Reassessment of the mental condition was conducted after 8 weeks of the pharmacological treatment also with the use of the HDRS scale. RESULTS: No significant statistical differences were found between the analysed groups as regards the intensity of depressive disorders. No differences in the expression of MnSOD, MPO, COX-2 and i-NOS genes on the level of both mRNA and protein were observed between both groups. No significant interrelation was noticed between the number of depression episodes experienced and the expression of selected genes on the mRNA level and protein level. CONCLUSIONS: There is no significant difference in MnSOD, MPO, COX-2 and i-NOS between patients with recurrent depressive disorders and those in a first episode of depression. These findings suggest that these enzymes are trait markers of depression and are not related to staging of depression.

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The release of reactive oxygen specie (ROS) by activated neutrophil is involved in both the antimicrobial and deleterious effects in chronic inflammation. The objective of the present investigation was to determine the effect of therapeutic plasma concentrations of non-steroidal anti-inflammatory drugs (NSAIDs) on the production of ROS by stimulated rat neutrophils. Diclofenac (3.6 µM), indomethacin (12 µM), naproxen (160 µM), piroxicam (13 µM), and tenoxicam (30 µM) were incubated at 37ºC in PBS (10 mM), pH 7.4, for 30 min with rat neutrophils (1 x 10(6) cells/ml) stimulated by phorbol-12-myristate-13-acetate (100 nM). The ROS production was measured by luminol and lucigenin-dependent chemiluminescence. Except for naproxen, NSAIDs reduced ROS production: 58 ± 2% diclofenac, 90 ± 2% indomethacin, 33 ± 3% piroxicam, and 45 ± 6% tenoxicam (N = 6). For the lucigenin assay, naproxen, piroxicam and tenoxicam were ineffective. For indomethacin the inhibition was 52 ± 5% and diclofenac showed amplification in the light emission of 181 ± 60% (N = 6). Using the myeloperoxidase (MPO)/H2O2/luminol system, the effects of NSAIDs on MPO activity were also screened. We found that NSAIDs inhibited both the peroxidation and chlorinating activity of MPO as follows: diclofenac (36 ± 10, 45 ± 3%), indomethacin (97 ± 2, 100 ± 1%), naproxen (56 ± 8, 76 ± 3%), piroxicam (77 ± 5, 99 ± 1%), and tenoxicam (90 ± 2, 100 ± 1%), respectively (N = 3). These results show that therapeutic levels of NSAIDs are able to suppress the oxygen-dependent antimicrobial or oxidative functions of neutrophils by inhibiting the generation of hypochlorous acid.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Introduction: In this report, we propose the application of the p-iodophenol-enhanced luminol chemiluminescent technique to the determination of peroxidase (myeloperoxidase and/or platelet peroxidase) activity in blasts of minimally differentiated acute myeloblastic leukemia (AML-M0) and acute megakaryoblastic leukemia (AML-M7).Methods: the frozen blast cells from 29 patients were thawed and submitted to the optimized protocol.Results: All cases of AML-M7 and AML-M0 exhibited integrated light emission greater than 73 (10(2) mV x s), which was the arbitrary cutoff point set for the discrimination between AML and acute lymphoblastic leukemia (ALL) (mean + 3 x s.d. of ALL samples, n = 10). In addition, five out of seven cases of AML-M0 showed results above the Cutoff point.Conclusion: This highly sensitive enhanced chemiluminescent technique may be applied to discriminate between ALL and AML-M7 or AML-M1 cases, and most AML-M0 cases. It is very simple, cheap and easy to perform compared to other procedures used to measure MPO activity in AML-leukemias including AML-M7 and AML-M0.