Rapid and reliable determination of the halogenating peroxidase activity in blood samples

Flemmig, Jörg; Schwarz, Pauline; Bäcker, Ingo; Leichsenring, Anna; Lange, Franziska; Arnhold, Jürgen

doi:10.1016/j.jim.2014.09.003

Cited by 9 publications

(8 citation statements)

References 36 publications

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“…the formation of hypochlorous acid, HOCl) of one of the most abundant neutrophil enzymes, namely myeloperoxidase (MPO). By using a standardised method the erythrocyte amount in the samples was diminished and the chlorinating MPO activity was measured by using the dye aminophenyl fluorescein (APF) [ 37 , 55 ]. To our knowledge such a repeated evaluation of the MPO activity whereby especially its HOCl-producing activity is addressed was not performed in an animal model before.…”

Section: Discussionmentioning

confidence: 99%

“…by α1AGP plasma levels or the scoring of clinical symptoms. In fact, in previous studies where we applied the same leukocyte enrichment method we observed that neutrophils from mice and rats, unlike human cells, do not show considerably increased FSC- or SSC-values during flow cytometry analysis [ 37 ].…”

Section: Discussionmentioning

confidence: 99%

“…Since neutrophils are much less abundant in mice and rats than in man [ 68 , 72 ] we expect that the determination of the HOCl-producing MPO activity could provide a suitable new marker for clinical studies on RA in man. This fact, the small amount of blood necessary for this analysis [ 37 ] and the assumption that the innate immune system, neutrophils and MPO may play a bigger role in RA as classically assumed [ 6 , 9 , 56 ] provide further arguments for considering the activity of this enzyme in future studies on rheumatoid arthritis.…”

Section: Discussionmentioning

confidence: 99%

“…Every two weeks about 500 μl of blood were taken from the retrobulbar venous plexus of the animals under anaesthesia (see 2.3 ). The blood was collected in small sample tubes containing 200 U Heparin, stored at 4°C in the dark with gentle agitation and analysed within 24 h. For the quick depletion of the erythrocytes from the blood samples and a subsequent staining of the MPO-positive leukocytes for flow cytometry analysis a previously published protocol was used with slight modifications [ 37 ]. Briefly, for each blood sample 100 μl were transferred to a 15 ml tube and two subsequent hypotonic lysis steps were performed by adding 2 ml Millipore water and, after 60 s, 5 ml PBS (10 mM, pH 7.4).…”

Section: Methodsmentioning

confidence: 99%

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Long-Term Effects of (–)-Epigallocatechin Gallate (EGCG) on Pristane-Induced Arthritis (PIA) in Female Dark Agouti Rats

et al. 2016

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Rheumatoid arthritis (RA)—a widespread chronic inflammatory disease in industrialized countries—is characterized by a persistent and progressive joint destruction. The chronic pro-inflammatory state results from a mutual activation of the innate and the adaptive immune system, while the exact pathogenesis mechanism is still under discussion. New data suggest a role of the innate immune system and especially polymorphonuclear granulocytes (PMNs, neutrophils) not only during onset and the destructive phase of RA but also at the chronification of the disease. Thereby the enzymatic activity of myeloperoxidase (MPO), a peroxidase strongly abundant in neutrophils, may be important: While its peroxidase activity is known to contribute to cartilage destruction at later stages of RA the almost MPO-specific oxidant hypochlorous acid (HOCl) is also discussed for certain anti-inflammatory effects. In this study we used pristane-induced arthritis (PIA) in Dark Agouti rats as a model for the chronic course of RA in man. We were able to shown that a specific detection of the HOCl-producing MPO activity provides a sensitive new marker to evaluate the actual systemic inflammatory status which is only partially detectable by the evaluation of clinical symptoms (joint swelling and redness measurements). Moreover, we evaluated the long-term pharmacological effect of the well-known anti-inflammatory flavonoid epigallocatechin gallate (EGCG). Thereby only upon early and continuous oral application of this polyphenol the arthritic symptoms were considerably diminished both in the acute and in the chronic phase of the disease. The obtained results were comparable to the treatment control (application of methotrexate, MTX). As revealed by stopped-flow kinetic measurements, EGCG may regenerate the HOCl-production of MPO which is known to be impaired at chronic inflammatory diseases like RA. It can be speculated that this MPO activity-promoting effect of EGCG may contribute to the pharmacological mode of action of this polyphenol.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Long-Term Effects of (–)-Epigallocatechin Gallate (EGCG) on Pristane-Induced Arthritis (PIA) in Female Dark Agouti Rats

et al. 2016

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“…In these experiments, we used aminophenyl-fluorescein (APF) as a substrate for MPO and hydroxyl-phenyl fluorescein (HPF) for assessments of peroxynitrite-driven oxidants. 42, 43 In both cases, highly fluorescent products were formed after oxidation reactions driven by MPO or ONOO – , respectively. We observe a ~2 fold higher oxidative potency detectable in the presence of MDSC from tumor-bearing animals compared to control non-activated cells (Fig.…”

Section: Resultsmentioning

confidence: 99%

Targeting myeloid regulators by paclitaxel-loaded enzymatically degradable nanocups

et al. 2018

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Tumor microenvironment is characterized by immunosuppressive mechanisms associated with the accumulation of immune regulatory cells - myeloid-derived suppressor cells (MDSC). Therapeutic depletion of MDSC has been associated with inhibition of tumor growth and therefore represents an attractive approach to cancer immunotherapy. MDSC in cancer are characterized by enhanced enzymatic capacity to generate reactive oxygen and nitrogen species (RONS) which have been shown to effectively degrade carbonaceous materials. We prepared enzymatically openable nitrogen-doped carbon nanotube cups (NCNC) corked with gold nanoparticles and loaded with paclitaxel as a therapeutic cargo. Loading and release of paclitaxel was confirmed through electron microscopy, Raman spectroscopy and LC-MS analysis. Under the assumption that RONS generated by MDSCs can be utilized as a dual targeting and oxidative degradation mechanism for NCNC, here we report that systemic administration of paclitaxel loaded NCNC delivers paclitaxel to circulating and lymphoid tissue MDSC resulting in the inhibition of growth of tumors (B16 melanoma cells inoculated into C57BL/6 mice) in vivo. Tumor growth inhibition was associated with decreased MDSC accumulation quantified by flow cytometry that correlated with bio-distribution of gold-corked NCNC resolved by ICP-MS detection of residual gold in mouse tissue. Thus, we developed a novel immunotherapeutic approach based on unique nanodelivery vehicles, which can be loaded with therapeutic agents that are released specifically in MDSC via NCNC selective enzymatic "opening" affecting change in the tumor microenvironment.

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Myeloperoxidase – ein neuer Marker zur Erforschung von Entzündungen?

2015

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Rapid and reliable determination of the halogenating peroxidase activity in blood samples

Cited by 9 publications

References 36 publications

Long-Term Effects of (–)-Epigallocatechin Gallate (EGCG) on Pristane-Induced Arthritis (PIA) in Female Dark Agouti Rats

Long-Term Effects of (–)-Epigallocatechin Gallate (EGCG) on Pristane-Induced Arthritis (PIA) in Female Dark Agouti Rats

Targeting myeloid regulators by paclitaxel-loaded enzymatically degradable nanocups

Myeloperoxidase – ein neuer Marker zur Erforschung von Entzündungen?

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