Evaluation of the antioxidant activity of passion fruit (Passiflora edulis and Passiflora alata) extracts on stimulated neutrophils and myeloperoxidase activity assays
; Serteyn, Didier ; et al
in Food Chemistry (2011), 128Detailed reference viewed: 130 (14 ULg)
Specific Immuno Extraction Followed by Enzymatic Detection (SIEFED), a new tool to measure active myeloperoxidase in complex media and to screen potential inhibitors of this enzyme.
Serteyn, Didier ; Mouithys-Mickalad, Ange ; et al
in The 7th International Human Peroxidase Meeting, 22-25 May 2011, Brussels (2011, May 25)
A method called SIEFED (“Specific Immuno Extraction Followed by Enzymatic Detection”) was developed for the specific measurement of myeloperoxidase (MPO) activity without interference of the sample medium ... [more ▼]
A method called SIEFED (“Specific Immuno Extraction Followed by Enzymatic Detection”) was developed for the specific measurement of myeloperoxidase (MPO) activity without interference of the sample medium. In this method, MPO is first extracted out of aqueous or biological samples by its capture by immobilized anti-MPO antibodies. A washing step then allows to eliminate the solution or biological fluid with interfering materials (proteins, lipids, reducing or oxidizing molecules, ...) and in a last step the activity of MPO bound to its antibodies is measured by using a sensitive detection system containing a fluorogenic substrate, hydrogen peroxide and nitrite as reaction enhancer. SIEFED is a method of choice to measure easily, quantitatively, and specifically the active part of MPO present in biological samples or complex media. Results obtained with this technique applied to biological samples emphasize the importance to distinguish the total MPO concentration of a sample obtained by ELISA from the active part of MPO, which is the real witness of the oxidant potential of the enzyme. SIEFED is also a powerful tool to study compounds or natural extracts that could have an inhibitory effect on the activity of MPO. Since the potential inhibitor is first incubated with the enzyme solution, and further eliminated by washing after the immunocapture of MPO, the tested compound or extract cannot interfere with the chromogenic substrate used to measure the activity of MPO or with products derived from the enzyme activity. Thus, an inhibitory effect could only be attributed to a direct interaction of the tested compound with the enzyme, either on the active site or another key position of the structure. In conclusion, the SIEFED technique opens new perspectives to study pathologies in which the release of active MPO is relevant and to select interesting compounds or extracts able to modulate the MPO activity. [less ▲]Detailed reference viewed: 129 (21 ULg)
Effect of benzoic acid analogs on myeloperoxidase activity measured by a new technique to study their direct interaction with the enzyme.
Franck, Thierry ; ; Mouithys-Mickalad, Ange et al
Poster (2011, May)
Myeloperoxidase (MPO) plays a key role in inflammatory response and constitutes a target for new drug development. The effects of some benzoic acid analogs were studied on the specific activity of human ... [more ▼]
Myeloperoxidase (MPO) plays a key role in inflammatory response and constitutes a target for new drug development. The effects of some benzoic acid analogs were studied on the specific activity of human MPO measured by SIEFED (“Specific Immunologic Extraction Followed by Enzymatic Detection”), an original method that consists of incubation of the compound with MPO, followed by capture of the enzyme by specific antibodies, washing (elimination of the compounds) and enzymatic detection of the immunocaptured enzyme. The compounds tested at 10-4, 10-5 and 10-6 M were studied in terms of structure activity relationship. Gallic acid (3,4,5-trihydroxybenzoic acid) with 3 hydroxyl groups had an important dose dependent inhibitory effect on MPO activity. Other molecules with less or without hydroxyl groups [3,4-dihydroxybenzoic acid, 2-hydroxybenzoic acid (salicylic acid) and benzoic acid] had rather an activator effect at 10-5 and 10-6 M. 2,4,6-Trihydroxybenzoic acid, with two hydroxyl groups adjacent to the carboxyl group, had a less efficient inhibitory effect. Caffeic acid (3,4-dihydroxycinnamic acid) with a propenoic acid group presented a dose dependent inhibitory effect on MPO activity contrary to its analog 3,4-dihydroxybenzoic acid. The esterification of the carboxyl group of gallic acid to obtain propyl gallate induced an activation of MPO at 10-5 and 10-6 M. Finally, the substitution of one or two hydroxyl groups by methoxyl ones (ferulic and syringic acids) decreased the efficiency of the molecules on the enzyme inhibition. The SIEFED technique appears as an innovative pharmacological tool to study the direct interaction of compounds with MPO. Number and position of hydroxyl groups and the extension of the carboxyl group of benzoic acid play a crucial role in the inhibition of MPO activity probably by facilitating the interaction with the active site or another elements of the enzyme structure. [less ▲]Detailed reference viewed: 62 (5 ULg)
Modulating effects of acepromazine on the reactive oxygen species production by stimulated equine neutrophils
Sandersen, Charlotte ; Mouithys-Mickalad, Ange ; de la Rebière de Pouyade, Geoffroy et al
in Veterinary Anaesthesia & Analgesia (2011), 38
To investigate the effect of acepromazine (ACP) on reactive oxygen species (ROS) production by stimulated equine neutrophils.Detailed reference viewed: 28 (8 ULg)
Flow cytometric detection of myeloperoxidase in horse neutrophils: a novel technique in equine diagnostic research.
; Franck, Thierry ; et al
in Veterinary Immunology and Immunopathology (2011), 144(3-4), 417-22
Myeloperoxidase (MPO) is a protein of interest due to its involvement in equine pathologies. Until now, results in equine diagnostic research were achieved through extracellular MPO detection. However ... [more ▼]
Myeloperoxidase (MPO) is a protein of interest due to its involvement in equine pathologies. Until now, results in equine diagnostic research were achieved through extracellular MPO detection. However, studying the cellular MPO content in neutrophils has revealed important insights in human diseases. This study aimed to develop a technique for the specific detection of MPO on the single cell level defining a flow cytometric protocol for the detection of both equine surface-bound and cellular MPO. Both indirect and direct labeling techniques are described which include the comparison of two secondary antibodies and two linking-fluorochromes, respectively. [less ▲]Detailed reference viewed: 21 (4 ULg)
Clinical significance of active myeloperoxidase in carotid atherosclerotic plaques
GACH, Olivier ; Magne, Julien ; Franck, Thierry et al
in International Journal of Cardiology (2011), 152(1), 149-151Detailed reference viewed: 56 (16 ULg)
Coll2-1, Coll2-1NO2 and myeloperoxidase concentrations in the synovial fluid of equine tarsocrural joints affected with osteochondrosis.
Verwilghen, Denis ; ; et al
in Veterinary Research Communications (2011), 35(7), 401-8
The measurement of biomarkers that reflect cartilage breakdown is a powerful tool for investigating joint damage caused by disease or injury. Particularly in cases of osteochondrosis, synovial ... [more ▼]
The measurement of biomarkers that reflect cartilage breakdown is a powerful tool for investigating joint damage caused by disease or injury. Particularly in cases of osteochondrosis, synovial concentrations of these biomarkers may reveal the presence of osteoarthritic changes. Coll2-1, Coll2-1 NO2 and myeloperoxidase have recently been introduced in equine osteoarticular research but comparison between the concentrations of these markers in OCD affected and healthy joints has not been made. Therefore, this study aimed at reporting the synovial concentrations of these biomarkers in joints affected with osteochondral fragments in the tarsocrural joint compared to unaffected joints. Myeloperoxidase and Coll2-1NO2 revealed to have similar levels between affected joints and controls. However, in contrast to previous studies using C2C the present study demonstrated that synovial levels of Coll2-1 were significantly elevated in tarsocrural joints affected with osteochondrosis. Thus, Coll2-1 may be an earlier marker of cartilage degeneration than other cartilage degradation markers that have been previously used in equine medicine. [less ▲]Detailed reference viewed: 26 (6 ULg)
Relationship between arthroscopic joint evaluation and the levels of Coll2-1, Coll2-1NO(2), and myeloperoxidase in the blood and synovial fluid of horses affected with osteochondrosis of the tarsocrural joint.
Verwilghen, Denis ; ; et al
in Osteoarthritis and Cartilage (2011), 19(11), 1323-9
OBJECTIVE: To evaluate the levels of plasmatic and synovial Coll2-1, Coll2-1NO(2) and myeloperoxidase (MPO) in horses with osteochondral lesions of the tarsocrural joint and to investigate how these ... [more ▼]
OBJECTIVE: To evaluate the levels of plasmatic and synovial Coll2-1, Coll2-1NO(2) and myeloperoxidase (MPO) in horses with osteochondral lesions of the tarsocrural joint and to investigate how these levels relate to arthroscopic findings of inflammation and degeneration. MATERIALS AND METHODS: Venous blood and synovial fluid samples were collected from 63 horses presented for arthroscopic removal of osteochondral fragments in the tarsocrural joint. Prior to removal of the osteochondral fragment, an exploration of the joint was performed and an inflammatory and degenerative score was determined. The blood and synovial levels of Coll2-1, Coll2-1NO(2) and MPO were also measured. The effects of the arthroscopic evaluation (inflammatory and degenerative classes) on the blood and synovial markers were evaluated using a linear model (GLM procedure), and correlations between biochemical markers in the blood and synovial fluid and the arthroscopic evaluation (inflammatory and degenerative classes) were established (Pearson's correlations). RESULTS: Significantly higher levels of Coll2-1 were detected in synovial fluid of higher degenerative classes. There was a significant correlation between the degenerative score and the synovial levels of Coll2-1 (r=0.27). According to the logistic regression model, there was a significant effect of the degenerative class on synovial levels of Coll2-1. CONCLUSIONS: Coll2-1 correlates well with the degenerative state of tarsocrural joints as evaluated by arthroscopy. This marker can therefore be classified as a burden-of-disease marker in the assessment of joint disease in horses. [less ▲]Detailed reference viewed: 29 (9 ULg)
Inhalation with NDS27 attenuates pulmonary neutrophilic inflammation in recurrent airway obstruction
Sandersen, Charlotte ; ; Franck, Thierry et al
in Veterinary Record : Journal of the British Veterinary Association (2011)Detailed reference viewed: 70 (25 ULg)
Do polyamines increase the antioxidant capacity of hyperhydric shoots ?
Franck, Thierry ; Tabart, Jessica ; Kevers, Claire et al
in 4th international workshop - cost action FA0605 - Book of abstracts - Limassol 17-19 November (2011)Detailed reference viewed: 42 (5 ULg)
Benefits of napping and an extended duration of recovery sleep on alertness and immune cells after acute sleep restriction.
; ; et al
in Brain, Behavior & Immunity (2011), 25(1), 16-24
Understanding the interactions between sleep and the immune system may offer insight into why short sleep duration has been linked to negative health outcomes. We, therefore, investigated the effects of ... [more ▼]
Understanding the interactions between sleep and the immune system may offer insight into why short sleep duration has been linked to negative health outcomes. We, therefore, investigated the effects of napping and extended recovery sleep after sleep restriction on the immune and inflammatory systems and sleepiness. After a baseline night, healthy young men slept for a 2-h night followed by either a standard 8-h recovery night (n=12), a 30-min nap (at 1 p.m.) in addition to an 8-h recovery night (n=10), or a 10-h extended recovery night (n=9). A control group slept 3 consecutive 8-h nights (n=9). Subjects underwent continuous electroencephalogram polysomnography and blood was sampled every day at 7 a.m. Leukocytes, inflammatory and atherogenesis biomarkers (high-sensitivity C-reactive protein, interleukin-8, myeloperoxidase, fibrinogen and apolipoproteins ApoB/ApoA), sleep patterns and sleepiness were investigated. All parameters remained unchanged in the control group. After sleep restriction, leukocyte and - among leukocyte subsets - neutrophil counts were increased, an effect that persisted after the 8-h recovery sleep, but, in subjects who had a nap or a 10-h recovery sleep, these values returned nearly to baseline. Inflammatory and atherogenesis biomarkers were unchanged except for higher myeloperoxidase levels after sleep restriction. The increased sleepiness after sleep restriction was reversed better in the nap and extended sleep recovery conditions. Saliva cortisol decreased immediately after the nap. Our results indicate that additional recovery sleep after sleep restriction provided by a midday nap prior to recovery sleep or a sleep extended night can improve alertness and return leukocyte counts to baseline values. [less ▲]Detailed reference viewed: 62 (3 ULg)
Modulatory activities of Agelanthus dodoneifolius (Loranthaceae) extracts on stimulated equine neutrophils and myeloperoxidase activity
; ; et al
in International Journal of Molecular Medicine (2011), 28Detailed reference viewed: 40 (4 ULg)
Association between Myeloperoxidase concentration in equine frozen semen and post thawing parameters
Ponthier, Jérôme ; Franck, Thierry ; Detilleux, Johann et al
in Reproduction in Domestic Animals (2010), 45(5), 811-816
Despite improvement of techniques, semen of 20% of stallions remains unfreezable. Recent studies focused on impact of reactive oxygen species and oxidant enzymes on semen characteristics. Myeloperoxidase ... [more ▼]
Despite improvement of techniques, semen of 20% of stallions remains unfreezable. Recent studies focused on impact of reactive oxygen species and oxidant enzymes on semen characteristics. Myeloperoxidase (MPO) is a pro-oxidant enzyme contained in and released by neutrophils during degranulation or after cell lysis. It is responsible for the formation of hypochlorous acid, a strong oxidant agent which could damage spermatozoa. The aim of this study was to determine the relation between MPO concentration and characteristics of frozen semen from stallions. Thirty five straws from different stallions were analyzed. Post-thawing spermatozoal concentration, progressive and total motility were determined by CASA. Freezability was determined according to post-thawing progressive motility (over or under 15%). Percent of alive spermatozoa and abnormal forms were determined after Eosin-Nigrosin and Diff-Quick® staining respectively. Post-thawing MPO concentration was measured by ELISA. Our study shows that frozen thawed semen contains large amounts of free MPO. We also observed that post-thawing MPO ELISA assay can be used as an indicator of equine semen freezability. High MPO concentration samples showed lower total and progressive motility. A higher proportion of abnormal head shape associated with acrosome reaction was observed in our late examinations of the high concentration MPO group. Our results show that MPO adversely affects total and progressive motility of equine semen. A negative correlation between normal motile forms and MPO concentration was also observed. The effect of MPO on dead or abnormal forms remains to be precised. [less ▲]Detailed reference viewed: 145 (54 ULg)
Antioxidant activity of Passiflora edulis and Passiflora alata fruits
; ; Serteyn, Didier et al
in Planta Medica (2010, September), 76(12), 1274-1275Detailed reference viewed: 84 (7 ULg)
Kit for the sequential measurement of (1) the enzymatically active fraction and (2) the total amount of an enzyme
Serteyn, Didier ; ; Franck, Thierry et al
The present invention is related to a combined kit for sequential measurement of the enzymatically active fraction and total amount of an enzyme [(such as myeloperoxidase (MPO)] in a sample, and that find ... [more ▼]
The present invention is related to a combined kit for sequential measurement of the enzymatically active fraction and total amount of an enzyme [(such as myeloperoxidase (MPO)] in a sample, and that find improved applications in veterinary and human health fields. [less ▲]Detailed reference viewed: 30 (7 ULg)
Development of an enzyme-linked immunosorbent assay for equine neutrophil elastase measurement in blood: Preliminary application to colic cases.
de la Rebière de Pouyade, Geoffroy ; Franck, Thierry ; Salciccia, Alexandra et al
in Veterinary immunology and immunopathology (2010)
Equine neutrophil elastase (NE) is a protease released in inflammatory diseases and participating in tissue destruction. To measure NE in horse plasma to assess its role in pathological conditions, we ... [more ▼]
Equine neutrophil elastase (NE) is a protease released in inflammatory diseases and participating in tissue destruction. To measure NE in horse plasma to assess its role in pathological conditions, we purified elastase from equine neutrophils by a double step chromatography and obtained a pure protein of 27kDa, 4kDa smaller than the NE 2A previously purified (Scudamore et al., 1993; Dagleish et al., 1999), which was likely to be NE 2B. We developed an ELISA by using two specific polyclonal antibodies obtained from rabbit and guinea pig. The sandwich complex was detected using a secondary antibody conjugated to alkaline phosphatase. The ELISA showed good precision and accuracy, with intra- and inter-assay coefficients of variation below 10% for equine NE concentrations ranging from 1.875 to 60ng/ml. A stable plasma NE value, unaffected by the delay of centrifugation (over 4h), was obtained with plasma from EDTA anticoagulated blood. The mean value (+/-SEM) measured in 37 healthy horses was 32.53+/-4.6ng/ml. NE level in plasma of horses with colic at the time of admission was significantly higher than in healthy horses. Our results indicate that the ELISA technique we developed to measure plasmatic NE is a powerful tool for studying the role of elastase in equine inflammatory disease. In future, the application will be extended to other equine biological fluids. [less ▲]Detailed reference viewed: 65 (9 ULg)
Is neutrophil elastase associated with myeloperoxidase concentration and post-thawing parameters in equine frozen semen?
Ponthier, Jérôme ; de la Rebière de Pouyade, Geoffroy ; et al
in Animal Reproduction Science (2010), 121S
Non sperm cells concentration is higher in unfreezable semen. A relation between non-sperm cells in fresh semen and MPO and post thawing quality has been observed. Neutrophil Elastase seems to have no ... [more ▼]
Non sperm cells concentration is higher in unfreezable semen. A relation between non-sperm cells in fresh semen and MPO and post thawing quality has been observed. Neutrophil Elastase seems to have no effect on semen characteristics and to be not associated with on-sperm cells and freezability. [less ▲]Detailed reference viewed: 99 (34 ULg)
EFFECT OF DIFFERENT ANOXIA/REOXYGENATION MODELS ON MITOCHONDRIAL COMPLEX I ACTIVITY OF CULTURED EQUINE SKELETAL MUSCLE CELLS: ESR AND OXYGRAPHIC STUDIES.
Ceusters, Justine ; Mouithys-Mickalad, Ange ; Niesten, Ariane et al
Poster (2010)Detailed reference viewed: 27 (10 ULg)
Specific immuno-extraction followed by enzymatic detection (SIEFED) of myeloperoxidase and mitochondrial complex I in muscular microbiopsies: preliminary results in endurance horses
Franck, Thierry ; Votion, Dominique ; Ceusters, Justine et al
in Equine Veterinary Journal. Supplement (2010), 42(Suppl. 38), 296-302Detailed reference viewed: 37 (15 ULg)
La microbiopsie musculaire : un nouvel outil pour le suivi sportif et la détection précoce des dysfonctions musculaires
Votion, Dominique ; Fraipont, Audrey ; et al
in 36ème Journée de la Recherche Equine (2010)
The objective of this study was to confirm the practical value of high-resolution respirometry (HRR) applied to biopsies to determine, in horses, the level of training, their athletic ability and for the ... [more ▼]
The objective of this study was to confirm the practical value of high-resolution respirometry (HRR) applied to biopsies to determine, in horses, the level of training, their athletic ability and for the early detection of muscular dysfunction. Materials and methods – The muscle mitochondrial respiration was determined by HRR in 20 endurance horses and 10 trotters sampled at the triceps brachii at different stages of their training. Results – Training increases mitochondrial respiration, in addition, the best performers had the highest rate of respiration. A trotter had abnormally low levels of muscle mitochondrial respiration for its level of training. This horse has presented several episodes of rhabdomyolysis during its racing season. Discussion – The biopsy is easily achievable by the attending veterinarian. This study shows that the athletic ability of horses is closely linked to respiratory muscle function, and suggests the value of HRR for performance prediction. In addition, the RHR has the ability to demonstrate mitochondrial dysfunction potentially responsible for exercise-induced rhabdomyolysis. [less ▲]Detailed reference viewed: 242 (48 ULg)