Search results for "myeloperoxidase"
showing 10 items of 74 documents
Allopurinol Protective Effect of Renal Ischemia by Downregulating TNF-α, IL-1β, and IL-6 Response
2016
Allopurinol is a well-known antioxidant that protects tissue against ischemia and reperfusion injury, blocking purine catabolism, and possibly reducing TNF-α and other cytokines. It also plays a significant role in reducing the inflammatory processes by inhibiting chemotaxis and other inflammatory mediators. The objective of this study was to define the role of allopurinol regarding kidney ischemic injury particularly as to its effect on inflammatory molecules such as TNF-α, IL-1β, and IL-6 response. One hundred and twenty five rats were subjected to warm renal ischemia. Five more animals were included as sham. Animal survival and plasma levels of lipid peroxidation, myeloperoxidase, lactat…
Influence of Dimerization of Apocynin on Its Effects in Experimental Colitis
2017
Apocynin has been widely used as an inhibitor of the nicotinamide adenine dinucleotide phosphate oxidase (NADPH-oxidase) system and shows promise as an anti-inflammatory drug. Diapocynin, the dimeric product generated by the oxidation of apocynin in the presence of myeloperoxidase (MPO), is supposed to be its active form. In this study, diapocynin has been chemically synthesized and its activity on several inflammatory mediators in LPS-stimulated RAW 264.7 macrophages and its anti-inflammatory effect on ulcerative colitis induced by dextran sodium sulfate (DSS) in mice analyzed. We found that diapocynin showed higher inhibitory activity than apocynin. The dimer reduced ROS production, TNF-α…
Bacteria-Derived Compatible Solutes Ectoine and 5α-Hydroxyectoine Act as Intestinal Barrier Stabilizers to Ameliorate Experimental Inflammatory Bowel…
2015
Earlier studies showed that the compatible solute ectoine (1) given prophylactically before induction of colitis by 2,4,6-trinitrobenzenesulfonic acid (TNBS) in rats prevented histological changes induced in the colon and the associated rise in inflammatory mediators. This study was therefore conducted to investigate whether ectoine (1) and its 5α-hydroxy derivative (2) would also be effective in treating an already established condition. Two days after inducing colitis in rats by instilling TNBS/alcohol in the colon, animals were treated orally once daily for 1 week with either 1 or 2 (50, 100, 300 mg/kg). Twenty-four hours after the last drug administration rats were sacrificed. Ulcerativ…
Protein oxidation in chronic kidney disease.
2013
An imbalance between oxidative processes and antioxidant systems has been widely demonstrated in chronic kidney diseases (CKD). In this study we enrolled 26 healthy subjects, 27 patients with CKD on conservative treatment (CT-CKD) with various degrees of renal failure, and 31 CKD subjects in haemodialysis treatment (HD-CKD), evaluated before and after a standard haemodialysis session. In each group we measured protein carbonyl groups (PC) as an index of protein oxidation, lipid peroxidation (TBARS) and two plasma markers of leukocyte activation, elastase and myeloperoxidase (MPO). In CT-CKD subjects the PC level was significantly higher than in normal controls, and it was negatively correla…
Increased Circulating Levels of 3-Nitrotyrosine Autoantibodies
2012
3-nitrotyrosine formation is an oxidative protein modification that was first discovered in vivo in the early 1990s by Beckman and colleagues.1,2 The biological relevance of this process was extensively investigated in the subsequent years and further facilitated by the development of 3-nitrotyrosine–specific antibodies.3 Protein tyrosine nitration is mainly mediated by 3 biochemical processes (Figure): (1) by peroxynitrite (ONOO−) formation,4–6 the reaction product of nitric oxide (•NO) and superoxide (•O2−); (2) by a (myelo)peroxidase-catalyzed nitrogen dioxide radical (•NO2) formation from hydrogen peroxide and nitrite;7,8 and (3) by a nonspecific formation of the nitrogen dioxide radica…
A novel rat model of chronic fibrosing cholangitis induced by local administration of a hapten reagent into the dilated bile duct is associated with …
2000
Abstract Background/Aim: The cholangiopathies represent hepatobiliary diseases in which bile-duct epithelial cells are targets for destructive processes, including immune-mediated damage. We describe a novel rat model of chronic fibrosing cholangitis induced by administration of the hapten reagent 2,4,6-trinitrobenzenesulfonic acid (TNBS) into the dilated bile duct. Methods: The common bile duct was dilated due to a mild stenosis in 8-week-old female Lewis rats. TNBS (50 mg/kg) was injected during a second laparotomy. Results: TNBS-treatment reproducibly resulted in chronic fibrosing cholangitis. In retrograde cholangiography the bile ducts showed irregularities, beading and strictures. Alk…
Inhibition of phospholipase A2 activities and some inflammatory responses by the marine product ircinin
1996
The marine product ircinin has been tested for its effects on secretory and cytosolic phospholipase A2 (PLA2) activities in vitro as well as for inhibition of cellular functions in human neutrophils and inflammatory responses in mice. Ircinin inhibited Naja naja venom, human synovial recombinant, bee venom and zymosan-injected rat air pouch PLA2 with IC50 values in the microM range, similar to those of the known inhibitor scalaradial. On the other hand, ircinin was less active on cytosolic PLA2 from human monocytes and decreased potently the release of LTB4 in human neutrophils. This marine product affected weakly human neutrophil functions like superoxide generation and degranulation. In t…
Elastase, myeloperoxidase, nitric oxide metabolites and oxidative status in subjects with clinical stable chronic renal failure on conservative treat…
2009
We evaluated, in a group of 41 CRF undialyzed subjects (29 men and 12 women, mean age 64.1 +/- 11.3 years), some parameters that reflect leukocyte activation (elastase, myeloperoxidase - MPO), plasma NO metabolites (NO(x)) and the oxidative status (lipid peroxidation expressed as thiobarbituric acid-reactive substances (TBARS) and total antioxidant status (TAS). Elastase was determined, on plasma separated from fasting venous blood, as elastase/alpha1-proteinase inhibitor complex. MPO was evaluated employing the Myeloperoxidase ELISA kit. The NO production was evaluated by a micromethod. The oxidation of polyunsaturated fatty acids was evaluated in plasma by detection of the thiobarbituric …
Involvement of secretory phospholipase A2 activity in the zymosan rat air pouch model of inflammation.
1996
1. In the zymosan rat air pouch model of inflammation we have assessed the time dependence of phospholipase A2 (PLA2) accumulation in the inflammatory exudates as well as cell migration, myeloperoxidase activity, prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) levels. 2. A significant increase in PLA2 activity was detected in 1,200 g supernatants of exudates 8 h after injection of zymosan into rat air pouch. This event coincided with peaks in cell accumulation (mainly neutrophils) and myeloperoxidase activity in exudates and was preceded by a rise in eicosanoid levels. 3. This enzyme (without further purification) behaved as a secretory type II PLA2 with an optimum pH at 7-8 units, lack o…
Plasma myeloperoxidase levels in acute brain ischaemia and high grade carotid stenosis.
2020
Myeloperoxidase (MPO) is an important oxidative enzyme participating in different stages of cardiovascular disease and predicts prognosis. Little is known about its role in acute cerebrovascular events and carotid plaque vulnerability. In this study, the aim was to assess plasma MPO levels in acute stroke patients and their correlation to stroke severity and stroke outcome.Plasma MPO levels were assessed in patients presenting with acute brain ischaemia within 36 h of symptom onset (n = 144, mean age 64.7 ± 11.6 years, 67% men) and in patients with moderate-to-severe carotid stenosis undergoing carotid artery stenting (n = 51, mean age 66.3 ± 8.4 years, 75% men). Patients presenting with ac…