Caffeinated instant coffee prevents an increase in exercise-mediated superoxide anion production in rat peritoneal neutrophils

The present study analyzed the in vivo effects of drinking caffeinated and decaffeinated instant coffee (8% w/v) by adult male Wistar rats submitted to high-intensity exercises. The parameters used in the evaluation were the determination of the activities of NADPH oxidase, myeloperoxidase and other antioxidant enzymes present in neutrophils of rats. It was observed that exercise-induced superoxide anion production depends on the NADPH oxidase activity (estimated by the cytochrome C reduction test) in peritoneal neutrophils (p < 0.05). The intake of caffeinated and decaffeinated instant coffee beverages and of a caffeine solution to 1.67% did not induced changes in the activities of the enzymes myeloperoxidase, superoxide dismutase and glutathione peroxidase (p < 0.05). But consumption of caffeinated instant coffee drink prevented an increase in NADPH oxidase-mediated superoxide production induced by highly intense exercise in rat neutrophils. While the decaffeinated instant coffee drink or caffeine solution alone did not affect NADPH oxidase-mediated superoxide production. We suggest that this activity is associated with the chemical composition and concentration of phenolic compounds and other antioxidant substances formed during roasting. From the obtained results, it was concluded that moderate intake of caffeinated instant coffee (equivalent to a daily human consumption of 4 50-mLcups of coffee) may have beneficial effects on health, contributing to a reduction in superoxide anion generation. Therefore, more research must be conducted to elucidate the mechanism of action of caffeinated coffee on NADPH oxidase in neutrophils.

Neutrophil oxidative burst as a diagnostic indicator of IgG-mediated anaphylaxis

BACKGROUND: IgG-mediated anaphylaxis occurs after infusion of certain monoclonal antibody-based therapeutics. New in vitro tests are urgently needed to diagnose such reactions. We investigated whether allergens trigger neutrophil oxidative burst (OB) and if neutrophil OB occurs due to allergen-specific IgG (sIgG). METHODS: Neutrophil OB was measured by dihydrorhodamine 123 flow cytometry using a leukocyte suspension spiked with a very small patch of the allergen crude extract, Dermatophagoides farinae (Der f). The mean fluorescence intensity ratio of stimulated to unstimulated samples was calculated as the neutrophil oxidative index (NOI). RESULTS: The Der f-specific NOI (Der f-sNOI) showed a time-dependent increase after Der f extract addition. At 15 min activation, higher Der f-sIgG levels were associated with lower Der f-sNOI values in 31 subjects (P < 0.05). This inverse relationship occurs due to the initial blocking effect of free Der f-sIgG. Additionally, neutrophil OB was nearly absent (Der f-sNOI of −1) in two cases: a subject with undetectable Der f-sIgG levels and washed leukocyte suspensions deprived of Der f-sIgG. CONCLUSION: Allergens can trigger neutrophil OB via preexisting allergen-sIgG. Neutrophil OB can be easily measured in a leukocyte suspension spiked with the allergen. This assay can be used to diagnose IgG-mediated anaphylaxis.

Anti-Helicobacter pylori activity and oxidative burst inhibition by the naphthoquinone 5-methoxy-3,4-dehydroxanthomegnin from Paepalanthus latipes

Helicobacter pylori is a bacterium recognized as the major cause of chronic gastritis and peptic ulcers. Infection by H. pylori induces inflammatory responses and pathological changes in the gastric microenvironment. The host Keywords: immune cells (especially neutrophils) release inflammatory mediators and large 5-methoxy-3,4-dehydroxanthomegnin amounts of reactive oxygen species (ROS), which are associated with an increased Helicobacter pyloririsk of developing gastric cancer. In this study, we evaluated the anti-H. pylori and oxidative burst antioxidantactivitiesofa1,4-naphthoquinone-5-methoxy-3,4-dehydroxanthomegnin. Paepalanthus latipes The antimicrobial activity was assessed using a spectrophotometric microdilution technique, and antioxidant activity was assessed by noting the effect of 5-methoxy3,4-dehydroxanthomegnin on the neutrophil oxidative burst using luminol-and lucigenin-amplified chemiluminescence. The results showed that 5-methoxy-3,4dehydroxanthomegnin is a potent anti-H. pylori compound (MIC 64 µg/mL and MBC 128 µg/mL) and a strong antioxidant. 5-Methoxy-3,4-dehydroxanthomegnin decreased luminol- and lucigenin-amplified chemiluminescence, with ED50 values of 1.58±0.09 µg/mL and 5.4±0.15 µg/mL, respectively, reflecting an inhibitory effect on the oxidative burst. These results indicate that 5-methoxy-3,4-dehydroxanthomegnin is a promising compound for the prevention and treatment of diseases caused by H. pylori infection, such as gastritis, peptic ulceration, and gastric cancer, because reactive oxygen intermediates are involved in the pathogenesis of gastric mucosal injury induced by H. pylori infections.

WBC count and functional changes induced by co-administration of clofazimine and clarithromycin, in single and multiple doses, in Wistar rats

Clofazimine and clarithromycin are used to treat leprosy and infections caused by Mycobacterium avium complex. Little data on the toxicity of co-administration of these two drugs are available. Here we evaluated the potential adverse effects of polytherapy with these two drugs in male Wistar rats by determining WBCs counts and other blood cell counts, neutrophilic phagocytosis, and burst oxidative, by flow cytometry. We observed an increase in WBCs, in multiple-dose regimens, and in polymorphonuclear cells, in both single- clarithromycin only and multiple dose regimens. We also observed a reduction in mononuclear cell counts in single and multiple doses. The drugs seem to reverse the mononuclear and polymorphonuclear cell ratio. An increase in oxidative burst was observed in animals treated with the drugs administered either individually or combined. In conclusion, clofazimine and clarithromycin change WBCs counts. Our results may contribute for a better understanding of the mechanisms related to the effects of co-administrating the two drugs.

Clofazimina e laritromicina são utilizadas no tratamento da hanseníase e em infecções causadas pelo complexo Mycobacterium avium. Devido à escassez de dados sobre a toxicidade de esquemas terapêuticos que associam estes fármacos, este estudo teve por objetivo avaliar os efeitos adversos desta terapia, em ratos machos Wistar, por meio da determinação da contagem global e específica de leucócitos e ensaios de fagocitose e burst oxidativo de neutrófilos por citometria de fluxo. Houve aumento do número de leucócitos (dose múltipla) e de células polimorfonucleares (doses única e múltipla) nos grupos tratados com claritromicina em monoterapia ou associada à clofazimina e redução das células mononucleares, em doses única e múltipla, nos mesmos grupos. Os fármacos parecem inverter a proporção entre células mono e polimorfonucleares. Observou-se aumento do burst oxidativo nos animais tratados com os fármacos isolados ou associados. Concluindo, clofazimina e claritromicina provocam alterações leucocitárias e os resultados podem contribuir para melhor entendimento dos mecanismos relacionados aos efeitos da administração dos fármacos em associação.

Age-Related Decrease and a Simple Flow Cytometric Assay of Neutrophil Function / 대한진단검사의학회지

BACKGROUND: We intended to confirm a decline in neutrophil function with aging and to devise a simple neutrophil function test protocol for use in a clinical setting. Reversely, the reliability of this protocol was to be verified by detectability of a decline in neutrophil function with aging. METHODS: Whole blood samples from young (thirties, N=32) and old (sixties, N=32) healthy subjects were incubated with the 7-aminoactinomycin D stained Escherichia coli. The mixture was stained by dihydrorhodamine 123 as an oxidative probe. Two kinds of fluorescence were measured by flow cytometry. RESULTS: Phagocytosis was declined with aging as indicated by a decrease in the percentage (form 28.2+/-9.5% to 21.9+/-10.9%, P<0.05) and the mean fluorescence intensity (MFI) ratio (from 1.67+/-0.27 to 1.51+/-0.27, P<0.05). Oxidative burst had a trend toward a decrease with aging, but the differences were not significant (percentage: from 35.3+/-13.2% to 32.1+/-14.1%, P=0.36; MFI ratio: from 5.26+/-3.23 to 5.08+/-3.55, P=0.84). CONCLUSIONS: The devised protocol in this study could detect a significant decline in neutrophil function with aging, and this protocol may be useful for the assessment of neutrophil function in a clinical setting.

Polymorphonuclear leukocyte functions enhanced by chemotaxis

Human polymorphonuclear leukocytes (PMN) migrate into tissues in response to chemoattractants, yet it is not known whether this process alters the functional capabilities of the PMN. Using recombinant human interleukin-8 (rHIL-8, 100 ng/ml) as a stimulus, we compared a population of PMN that migrated through a polyvinylpyrrolidone-coated polycarbonate filter containing 8.0 microns diameter pores with PMN stimulated in suspension. PMN were analyzed by flow cytometry according to functional and phenotypic criteria. CD11b/CD16 expression was unaltered by chemotaxis. In contrast, chemotaxis enhanced phagocytosis of E. coli, independent of opsonization with IgG. Similarly, chemotaxis increased baseline hydrogen peroxide production. We conclude that the chemotactic motion of PMN "primes" the cell for increased oxidative burst activity and augments the ability of PMN to ingest bacteria. This increased functional capability is distinct from rHIL-8 stimulation and appears to be independent of complement-and Fc-receptor expression.