References of "Lekeux, Pierre"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailLes tests de bronchoprovocation à la métacholine dans le diagnostic de l'hyperréactivité bronchique chez le cheval asymptomatique
Frippiat, Thibault ULg; Frellstedt, Linda ULg; Bustin, Jean-Clément ULg et al

in Proceedings de la 38ème Journée de la Recherche Equine (2012)

The clinical examination and the ancillary tests at the disposal from the veterinarian may be poor diagnostics in horses suffering from subclinical inflammatory airway disease or in clinical remission of ... [more ▼]

The clinical examination and the ancillary tests at the disposal from the veterinarian may be poor diagnostics in horses suffering from subclinical inflammatory airway disease or in clinical remission of recurrent airway obstruction (RAO). The objective of this study was to determine whether the methacholine bronchoprovocation test -which is daily used for diagnosis of asymptomatic human asthma- may be used as an applicable and repeatable method for the diagnosis of an increased susceptibility to bronchospasm in horses. The test, realised on 8 horses (6 with RAO history and 2 controls) presents a good feasibility and significant repeatability. Dust exposure increased the bronchoreactivity, while it did not affect other clinical and functional parameters or inflammatory markers. In the future, the bronchoprovocation test could therefore find its place in clinicat practice for the detection of asymptomatic horses which are susceptible to develop bronchospasm in poor environmental conditions. [less ▲]

Detailed reference viewed: 82 (18 ULg)
Full Text
Peer Reviewed
See detailResident CD11b(+)Ly6C(-) Lung Dendritic Cells Are Responsible for Allergic Airway Sensitization to House Dust Mite in Mice.
Mesnil, Claire ULg; Sabatel, Catherine ULg; Marichal, Thomas ULg et al

in PLoS ONE (2012), 7(12), 53242

Conventional dendritic cells (DCs) are considered to be the prime initiators of airway allergy. Yet, it remains unclear whether specific DC subsets are preferentially involved in allergic airway ... [more ▼]

Conventional dendritic cells (DCs) are considered to be the prime initiators of airway allergy. Yet, it remains unclear whether specific DC subsets are preferentially involved in allergic airway sensitization. Here, we systematically assessed the respective pro-allergic potential of individually sorted lung DC subsets isolated from house dust mite antigen (HDM)-treated donor mice, following transfer to naive recipients. Transfer of lung CD11c(+)CD11b(+) DCs, but not CD11c(+)CD11b(-)CD103(+) DCs, was sufficient to prime airway allergy. The CD11c(+)CD11b(+) DC subpopulation was composed of CD11c(+)CD11b(+)Ly6C(+) inflammatory monocyte-derived cells, whose numbers increase in the lungs following HDM exposure, and of CD11c(+)CD11b(+)Ly6C(-) DCs, which remain stable. Counterintuitively, only CD11c(+)CD11b(+)Ly6C(-) DCs, and not CD11c(+)CD11b(+)Ly6C(+) DCs, were able to convey antigen to the lymph nodes and induce adaptive T cell responses and subsequent airway allergy. Our results thus support that lung resident non-inflammatory CD11c(+)CD11b(+)Ly6C(-) DCs are the essential inducers of allergic airway sensitization to the common aeroallergen HDM in mice. [less ▲]

Detailed reference viewed: 27 (10 ULg)
Full Text
Peer Reviewed
See detailIncreased hypoxia-inducible factor 1alpha expression in lung cells of horses with recurrent airway obstruction.
Toussaint, Marie ULg; Fievez, Laurence ULg; Desmet, Christophe ULg et al

in BMC Veterinary Research (2012), 8(1), 64

ABSTRACT: BACKGROUND: Recurrent airway obstruction (RAO, also known as equine heaves) is an inflammatory condition caused by exposure of susceptible horses to organic dusts in hay. The immunological ... [more ▼]

ABSTRACT: BACKGROUND: Recurrent airway obstruction (RAO, also known as equine heaves) is an inflammatory condition caused by exposure of susceptible horses to organic dusts in hay. The immunological processes responsible for the development and the persistence of airway inflammation are still largely unknown. Hypoxia-inducible factor (Hif) is mainly known as a major regulator of energy homeostasis and cellular adaptation to hypoxia. More recently however, Hif also emerged as an essential regulator of innate immune responses. Here, we aimed at investigating the potential involvement of Hif1-alpha in myeloid cells in horse with recurrent airway obstruction. RESULTS: In vitro, we observed that Hif is expressed in equine myeloid cells after hay dust stimulation and regulates genes such as tumor necrosis factor alpha (TNF-alpha), interleukin-8 (IL-8) and vascular endothelial growth factor A (VEGF-A). We further showed in vivo that airway challenge with hay dust upregulated Hif1-alpha mRNA expression in myeloid cells from the bronchoalveolar lavage fluid (BALF) of healthy and RAO-affected horses, with a more pronounced effect in cells from RAO-affected horses. Finally, Hif1-alpha mRNA expression in BALF cells from challenged horses correlated positively with lung dysfunction. CONCLUSION: Taken together, our results suggest an important role for Hif1-alpha in myeloid cells during hay dust-induced inflammation in horses with RAO. We therefore propose that future research aiming at functional inactivation of Hif1 in lung myeloid cells could open new therapeutic perspectives for RAO. [less ▲]

Detailed reference viewed: 28 (1 ULg)
Full Text
Peer Reviewed
See detailAssessing fitness in endurance horses
Fraipont, Audrey ULg; Van Erck, Emmanuelle; Ramery, Eve ULg et al

in Canadian Veterinary Journal = Revue Vétérinaire Canadienne (2012), 53

A field test and a standardized treadmill test were used to assess fitness in endurance horses. These tests discriminated horses of different race levels: horses participating in races of 120km and more ... [more ▼]

A field test and a standardized treadmill test were used to assess fitness in endurance horses. These tests discriminated horses of different race levels: horses participating in races of 120km and more showed higher values of VLA4 (velocity at which blood lactate reached 4 mmol/L) and V200 (velocities at which heart rates reached 200 beats per min) than horses of lower race levels. [less ▲]

Detailed reference viewed: 61 (15 ULg)
Full Text
Peer Reviewed
See detailMyeloid HIF-1alpha prevents airway allergy in mice by promoting macrophage-mediated immunosuppression
Toussaint, Marie ULg; Fievez, Laurence ULg; Lekeux, Pierre ULg et al

in Proceedings of the 1st Scientific Meeting of the Faculty of Veterinary Medicine (2011, December 09)

Detailed reference viewed: 22 (9 ULg)
Full Text
Peer Reviewed
See detailExercise and epinephrine affect equine leukocytes distribution and gene expression in a distinct but closely related pattern
Ramery, Eve ULg; Schoenecker, Julie; Art, Tatiana ULg et al

in Veterinary Clinical Pathology (2011, December), 40(4), 583-584

Background: In horses-athletes, exercise has been shown to be an important regulator of immune cells and their functions, and catecholamines to be essential components of the physiological response to ... [more ▼]

Background: In horses-athletes, exercise has been shown to be an important regulator of immune cells and their functions, and catecholamines to be essential components of the physiological response to exercise. Objectives: The purpose of the present study was to compare immunological reactions and molecular events during exercise and epinephrine infusion. Methods: Horses were submitted to exercise or epinephrine infusion for 10 min. Blood samples were collected at T0, T5, Tl0, T20 and T40 min for biochemistry and haematology at T0 and T20 min for RNA extraction and microarray analysis. Results: In both protocols, packed-cell-volume and neutrophils peaked at T5 and T10, and returned to baseline at T40. Lymphocytes increased at T5 with exercise and at T20 with epinephrine and then remained high until the end of the protocols. Between T0 and T20, 55 probes, coding for 25 genes, and 19 probes, coding for 11 genes, were differentially regulated with epinephrine and exercise respectively (P<0.001). Ten of the genes over-expressed with epinephrine were related to inflammatory response and leukocytes trafficking and activation. Among the genes with the highest significant fold changes following exercise were FOS, DUSP-1 and CXCL1. FOS was over-expressed in both conditions. Among genes differentially regulated, Ingenuity software identified 3 overlapping functional networks with epinephrine and 1 functional network with exercise that overlapped the 3 epinephrine networks. Conclusions: Circulating leukocytes distribution and gene expression are rapidly affected following exercise and epinephrine infusion. Distinct but closely-related sets of gene activities were shown to be altered with exercise and epinephrine, with lesser changes in the immunological pattern with physical stress than epinephrine alone, arguing for compensatory mechanisms in exercise. [less ▲]

Detailed reference viewed: 75 (14 ULg)
Full Text
Peer Reviewed
See detailDNA released from dying host cells mediates aluminum adjuvant activity
Marichal, Thomas ULg; Ohata, Keiichi; Bedoret, Denis et al

in Nature Medicine (2011), 17

Aluminum-based adjuvants (alum) are widely used in human vaccination, although little is understood of their mechanisms of action. Here, we report that, in mice, alum causes the release of host cell DNA ... [more ▼]

Aluminum-based adjuvants (alum) are widely used in human vaccination, although little is understood of their mechanisms of action. Here, we report that, in mice, alum causes the release of host cell DNA, which acts as a potent endogenous immunostimulatory signal mediating alum adjuvant activity. Furthermore, we propose that host DNA signaling differentially regulates IgE and IgG1 production upon alum immunization. Indeed, we support that host DNA induces primary B cell responses, including IgG1 production, through Interferon Response Factor (Irf) 3-independent mechanisms, and 'canonical' type 2 T cell responses associated with IgE isotype switching and peripheral effector responses through Irf3-dependent mechanisms. The finding that host cell DNA is a damage-associated molecular pattern relaying alum adjuvant activity may thus help in the comprehension of the mechanisms of action of current vaccines and in the design of novel adjuvants. [less ▲]

Detailed reference viewed: 128 (26 ULg)
Peer Reviewed
See detailInterferon Response Factor-3 is essential for house dust mite-induced airway allergy
Marichal, Thomas ULg; Bedoret Denis; Mesnil Claire et al

in Proceedings of the Belgian Thoracic Society Annual Meeting (2011, May 23)

Detailed reference viewed: 52 (15 ULg)
See detailIRF3 is essential for house dust mite-induced airway allergy in mice
Marichal, Thomas ULg; Bedoret, Denis; Mesnil, Claire ULg et al

in Proceedings GIGA-Day 2011 (2011, May)

Detailed reference viewed: 20 (9 ULg)
See detailInterferon Response Factor 3 is essential for house dust mite-induced airway allergy
Marichal, Thomas ULg; Bedoret, Denis; Mesnil, Claire et al

Conference (2011, May)

Detailed reference viewed: 12 (0 ULg)
Peer Reviewed
See detailRelease and innate immune detection of host cell DNA mediate the adjuvant activity of aluminum salts
Marichal, Thomas ULg; Ohata, K; Bedoret, D et al

Poster (2011)

Detailed reference viewed: 14 (1 ULg)
Peer Reviewed
See detailRelease and innate immune detection of host cell DNA mediate the adjuvant activity of aluminum salts
Marichal, Thomas ULg; Ohata, K; Bedoret, Denis et al

Conference (2011)

Detailed reference viewed: 8 (1 ULg)
Peer Reviewed
See detailSelf-DNA release mediates the adjuvant effects of aluminum salts
Marichal, Thomas ULg; Ohata, K; Bedoret, Denis et al

Poster (2011)

Detailed reference viewed: 4 (0 ULg)
Full Text
Peer Reviewed
See detailLe microdamier d’expression : un outil performant dans la compréhension de la réponse
Schoeneker, Julie; Art, Tatiana ULg; Pirottin, Dimitri ULg et al

in Annales de Médecine Vétérinaire (2011), 154

Malgré de multiples études, les interrelations entre l’exercice, le stress et la réponse immune sont peu définies. Or, la compréhension de ces interrelations pourrait jouer un rôle très important dans ... [more ▼]

Malgré de multiples études, les interrelations entre l’exercice, le stress et la réponse immune sont peu définies. Or, la compréhension de ces interrelations pourrait jouer un rôle très important dans l’amélioration de la santé et des résultats sportifs des athlètes. En effet, l’exercice peut être reconnu comme un stress. Il induit des modifications de l’équilibre homéostatique qui peuvent à leur tour altérer la réponse immunitaire de l’hôte et donc sa susceptibilité aux maladies. L’adrénaline est la molécule essentielle de tout processus de stress. La technologie des microdamiers, outil majeur d’investigation transcriptomique, permet l’étude de l’expression génique de l’ensemble du génome. Son utilisation devrait donc permettre de mieux caractériser et définir les interrelations entre l’exercice, le stress et la réponse immune. Cette revue recense les interrelations connues entre la réponse immune à un stress adrénergique d’une part et la réponse immune à l’exercice d’autre part. Elle considère en outre la contribution potentielle des microdamiers à une meilleure compréhension des effets d’un stress, et plus particulièrement celui lié à l’exercice, sur l’immunité. [less ▲]

Detailed reference viewed: 43 (12 ULg)
Full Text
See detailInvestigation of the innate immunity in the lower respiratory tract in exercising horses
Frellstedt, Linda ULg; Gosset, Philippe; Desmet, Christophe ULg et al

in Proceedings of the 1st Scientific Meeting of the Faculty of Veterinary Medicine (2011)

Detailed reference viewed: 37 (8 ULg)
Full Text
Peer Reviewed
See detailResults of a haplotype-based GWAS for recurrent laryngeal neuropathy in the horse.
Dupuis, Marie-Capucine ULg; Zhang, Zhiyan ULg; Druet, Tom ULg et al

in Mammalian Genome : Official Journal of the International Mammalian Genome Society (2011)

Recurrent laryngeal neuropathy (RLN) is a major upper-airway disease of horses that causes abnormal respiratory noise during exercise and can impair performance. Etiopathogenesis remains unclear but ... [more ▼]

Recurrent laryngeal neuropathy (RLN) is a major upper-airway disease of horses that causes abnormal respiratory noise during exercise and can impair performance. Etiopathogenesis remains unclear but genetic factors have been suspected for many decades. The objective of this study was to identify risk loci associated with RLN. To that end we genotyped 234 cases (196 Warmbloods, 20 Trotters, 14 Thoroughbreds, and 4 Draft horses), 228 breed-matched controls, and 69 parents with the Illumina Equine SNP50 BeadChip. Using these data, we quantified population structure and performed single-marker and haplotype-based association studies, as well as family-based linkage analyses. We accounted for population stratification by modeling a random polygenic background effect with covariance structure estimated from genome-wide SNP data. Using the haplotype-based approach, we identified two genome-wide suggestive loci in Warmbloods, respectively on chromosomes 21 (p = 1.62 x 10(-6)) and 31 (p = 1.69 x 10(-5)). The two signals were driven by the enrichment of a "protective" haplotype in controls compared to cases. [less ▲]

Detailed reference viewed: 32 (10 ULg)