Pharmacological intervention with oxidative burst in human neutrophils.

In this study we investigated the effect of five therapeutically used drugs and four natural polyphenolic compounds on the mechanism of oxidative burst of human neutrophils concerning their participation in the generation of reactive oxygen species (ROS). The compounds investigated decreased the oxidative burst of whole blood in the rank order of potency: N-feruloylserotonin > quercetin > curcumin > arbutin > dithiaden > carvedilol. The generation of intracellular reactive oxygen species in isolated neutrophils decreased in the same rank order, while carvedilol was ineffective.

On the pharmacology of oxidative burst of human neutrophils.

The effect of three therapeutically used drugs and five polyphenolic compounds on the mechanism of oxidative burst was compared in whole blood and isolated neutrophils at cellular and molecular level. In 10 microM concentration, the compounds investigated decreased the oxidative burst of whole blood in the rank order of potency: N-feruloylserotonin (N-f-5HT) > curcumin (CUR) > quercetin (QUER) > arbutin (ARB) > resveratrol (RES) > dithiaden (DIT) > carvedilol (CARV) > brompheniramine (BPA). The ratio between the percentage inhibition of extracellular versus intracellular chemiluminescence (CL) followed the rank order QUER > N-f-5HT > RES > CUR > DIT and is indicative of the positive effect of the compounds tested against oxidative burst of neutrophils, demonstrating suppression of reactive oxygen species extracellularly with minimal alteration of intracellular reactive oxygen species (ROS).

Arbutin and decrease of potentially toxic substances generated in human blood neutrophils.

Neutrophils, highly motile phagocytic cells, constitute the first line of host defense and simultaneously they are considered to be central cells of chronic inflammation. In combination with standard therapeutic procedures, natural substances are gaining interest as an option for enhancing the effectiveness of treatment of inflammatory diseases. We investigated the effect of arbutin and carvedilol and of their combination on 4β-phorbol-12β-myristate-13α-acetate- stimulated functions of human isolated neutrophils.

Quercetin inhibits degranulation and superoxide generation in PMA stimulated neutrophils.

Activated neutrophils represent the main source of myeloperoxidase (MPO), superoxide (SO) and subsequently derived oxygen metabolites. They have important microbicidal activities, however in inflammatory conditions they may secondarily attack surrounding tissues. Overproduction of reactive oxygen species, prolonged or excessive liberation of MPO and other effective yet also toxic substances from neutrophils may participate in disturbed apoptosis, intensify the inflammatory processes and result in serious human diseases.

Effect of stilbene derivative on superoxide generation and enzyme release from human neutrophils in vitro.

Neutrophils represent the body's primary line of defense against invading pathogens. They most rapidly reach the site of injury or infection, liberate antimicrobial proteins, proteases and produce reactive oxygen species. Prolonged or excessive liberation of these very effective and toxic substances could intensify the inflammatory process and enhance tissue damage in many diseases, such as allergies, infections and rheumatoid arthritis.

Modulation of metabolic activity of phagocytes by antihistamines.

The purpose of the study was to investigate the effects of H(1)-antihistamines of the 1(st) generation (antazoline, bromadryl, brompheniramine, dithiaden, cyclizine, chlorcyclizine, chlorpheniramine, clemastine) and the 2(nd) generation (acrivastine, ketotifen, and loratadine) on the respiratory burst of phagocytes. Reactive oxygen species generation in neutrophils isolated from rat blood was measured using luminol-enhanced chemiluminescence. Changes in nitrite formation and iNOS protein expression by RAW 264.

In vivo effect of pinosylvin and pterostilbene in the animal model of adjuvant arthritis.

Objective: The aim of this study was to evaluate the effects of pinosylvin (PIN) and pterostilbene (PTE), natural substances from the stilbenoid group, on the development of adjuvant arthritis in rats.

Methods: Adjuvant arthritis (AA) was induced by a single intradermal injection of Mycobacterium butyricum in incomplete Freund's adjuvant in male Lewis rats. Our experiments included healthy intact animals as reference controls, arthritic animals without any drug administration, and arthritic animals with administration of PIN and PTE in the oral daily dose of 30 mg/kg b.

H1-antihistamines and oxidative burst of professional phagocytes.

Objectives: We analysed and compared the effect of five H1-antihistamines on stimulated oxidative burst at extra- and intracellular level of isolated and stimulated human polymorphonuclear leukocytes.

Design: Oxidative burst of isolated human neutrophils was studied by means of luminol and isoluminol enhanced chemiluminescence.

Results: The following rank order of potency for H1-antihistamines to decrease chemiluminescence was evaluated extracellularly: dithiaden> loratadine> chlorpheniramine> brompheniramine> pheniramine and at intracellular site: loratadine> dithiaden.

Carvedilol and adrenergic agonists suppress the lipopolysaccharide-induced NO production in RAW 264.7 macrophages via the adrenergic receptors.

The interaction of adrenergic agonists and/or antagonists with the adrenergic receptors expressed on immunologically active cells including macrophages plays an important role in regulation of inflammatory responses. Our study investigated the effects of carvedilol, a unique vasodilating beta-adrenergic antagonist, and endogenous adrenergic agonists (adrenalin, noradrenalin, and dopamine) and/or antagonists (prazosin, atenolol) on lipopolysaccharide-stimulated nitric oxide (NO) production from murine macrophage cell line RAW 264.7.

Effect of carvedilol on the production of reactive oxygen species by HL-60 cells.

Objectives: The generation of reactive oxygen species (ROS) by phagocytes is one of the irreplaceable microbicidal tools of innate immunity. It has been reported in our previous studies that short-term treatment by carvedilol ex vivo inhibits ROS generation. The purpose of this study was to investigate the long-term effect of carvedilol on phagocytes.

Effect of the extract from salivary glands of Lucilia sericata on human neutrophils.

Objectives: There is incomplete information about host immune response to maggot therapy, nowadays increasingly used to clean chronic wounds from necrotic debris and infection. Maggots are applied to the wound during the inflammatory phase. At the same time neutrophils infiltrate the inflammatory site as the first defense line of the organism.

Inhibition of superoxide generation and myeloperoxidase release by carvedilol after receptor and nonreceptor stimulation of human neutrophils.

Objectives: To compare three stimuli which activate human neutrophils with different signal transduction mechanisms, in order to better localize the effect of the beta-adrenoceptor antagonist carvedilol (CARV) on superoxide generation (O2*-) and myeloperoxidase release (MPO). The effect of CARV [0.1-100 micromol/l] on O2*- generation and MPO release from isolated human neutrophils was studied after specific receptor activator N-formyl-methionyl-leucyl-phenylalanine (fMLP) and nonreceptor phorbol-12-myristate-13-acetate (PMA) and calcium ionophor (A23187) stimuli.

Effect of carvedilol on reactive oxygen species and enzymes linking innate and adaptive immunity.

Objectives: Neutrophils and macrophages are critical components of our innate host defenses. They are a potential source of nitric oxide (NO) and superoxide, known to play an important role in many physiological processes including defense, immune and inflammatory responses. Myeloperoxidase (MPO), a major NO scavenger and a marker of oxidative stress, as well as increased inducible nitric oxide synthase (iNOS) expression, may affect the NO-superoxide balance, critical for cellular redox balance in the cardiovascular system at physiologic conditions.

On the pharmacology and toxicology of neutrophils.

Objectives: To study the effect of H1-antihistamines dithiaden (Dit) and loratadine (Lor) and compare it with that of histamine (His) on phorbolmyristate acetate (PMA) stimulated chemiluminescence (CL) of whole blood, isolated neutrophils, release of myeloperoxidase (MPO), and on superoxide (SO) generation.

Methods: Luminol- and isoluminol-enhanced CL was applied for measuring the oxidative burst, spectrophotometry was used for determination of MPO (o-dianisidine) and SO generation (superoxide dismutase inhibition of cytochrome c).

Results: Dit and Lor dose-dependently inhibited CL of whole blood and significantly decreased oxidative burst both at the extra- and intracellular sites of neutrophils.

In vitro effect of carvedilol on professional phagocytes.

Aim: Superfluous reactive nitrogen and oxygen species generation is implicated in the damage of tissues at sites of inflammation where activated neutrophils and macrophages are involved. This study was conducted to investigate whether the beneficial effects of carvedilol involve modulation of respiratory burst, degranulation-myeloperoxidase release and inducible nitric oxide synthase (iNOS) expression.

Methods: Spectrophotometry and chemiluminescence were used to evaluate the effect of carvedilol on opsonized zymosan (0.

Inhibitory effect of stobadine on FMLP-induced chemiluminescence in human whole blood and isolated polymorphonuclear leukocytes.

The chemiluminescence (CL) technique with luminol and isoluminol was used to characterize the effect of stobadine on reactive oxygen metabolites (ROM) generation in human whole blood and in isolated polymorphonuclear leukocytes (PMNL) stimulated with N-formyl-methionyl-leucyl-phenyl-alanine (FMLP). In whole blood and in isolated PMNL, stobadine in the concentrations of 1, 10 and 100 micromol/L significantly inhibited the CL signal after FMLP, which activated predominantly extracellular generation of ROM. The same concentrations of stobadine were effective on CL in a cell-free system.

Influence of carvedilol on superoxide generation and enzyme release from stimulated human neutrophils.

Activation of neutrophils induces generation of reactive oxygen species and release of granule enzymes, which not only participate in the bactericidal mechanisms of these cells, but also in possible tissue damage. We studied the effect of carvedilol (CARV) [0.1-100 micromol/l], an antihypertensive and cardiovascular drug with antioxidative properties, on superoxide generation (SO) and myeloperoxidase (MPO) release from isolated human neutrophils stimulated with fMLP, a specific receptor activator, or with PMA, a receptor bypassing stimulus.

Stobadine-modulated human neutrophil functional responsiveness: effect on particular and soluble stimulation.

The effect of stobadine on degranulation (myeloperoxidase release) and on oxidative burst, measured as superoxide anion production, was investigated in human neutrophils activated with receptor-specific (fMLP, opsonized zymosan) and nonreceptor stimuli (PMA, A 23187). Wortmannin, a specific inhibitor of 1-phosphatidylinositol 3-kinase, significantly inhibited fMLP-stimulated generation only. This effect was pronounced by stobadine.

Effect of stobadine on opsonized zymosan stimulated generation of reactive oxygen species in human blood cells.

To predict more precisely the effect of stobadine, a pyridoindole antioxidant agent, in the whole organism, we studied its effect on opsonized zymosan-stimulated free radical generation in whole blood, on superoxide generation in the mixture of PMNL : platelets (1:50), as well as on superoxide generation and myeloperoxidase release in isolated PMNL. Without stimulation, stobadine had no effect on reactive oxygen species (ROS) generation and myeloperoxidase release. Stobadine in a concentration of 10 or 100 micromol/l significantly decreased luminol-enhanced chemiluminescence in opsonized zymosan-stimulated whole blood.

Comparison of isoproterenol-induced changes in lysosomal enzyme activity in vivo and in vitro.

Isoproterenol was used as a drug which, when administered in high doses, is able to induce lysosomal enzyme activity changes in in vivo conditions. We correlated lysosomal enzyme activity in the absence and presence of isoproterenol, obtained in whole animals and in HeLa and HepG2 cells in tissue culture. In vivo experiments: male Wistar rats (270-300 g) were treated subcutaneously with isoproterenol in various doses.

Effect of stobadine on oxygen free radical generation in stimulated human polymorphonuclear leukocytes.

The generation both superoxide and a mixture of reactive oxygen species was recorded in a suspension of human polymorphonuclear leukocytes stimulated with phorbol myristate acetate. While stobadine dose-dependently decreased chemiluminescence, only its highest concentration used reduced significantly superoxide generation. The results suggest that stobadine is a more effective scavenger of free radicals rather than a quencher of superoxide anion.