Diagnostic imaging of equine thoracolumbar disorders

Equine thoracolumbar conditions represent a major cause of poor performance and locomotor disorders in sports and race horses. Advances in diagnostic imaging during the last 15 years allow today to diagnose most equine back lesions in the standing sedated horse. Radiography is the first choice imaging modality due to its high diagnostic performance. Ultrasonography is a complementary modality to further investigate back soft tissues and the caudal lumbar area not evaluable radiographically in the standing horse. Bone scintigraphy is a more complex and expensive technique and is usually dedicated to complicated clinical cases. The most frequent injuries diagnosed using these 3 modalities are kissing spines, osteo-arthrosis of the synovial intervetebral joints, vertebral spondylosis and muscle injuries. Clinical significance of these lesions should be interpreted with care considering the clinical signs exhibited by the horse but also its sports or racing useLes affections vertébrales thoracolombaires représentent une cause fréquente de baisse de performances et/ou de troubles locomoteurs chez les chevaux de sport et de courses. Le développement des techniques d’imagerie ces 15 dernières années permet aujourd’hui au vétérinaire équin de diagnostiquer un grand nombre de lésions affectant la colonne thoracolombaire sur le cheval debout tranquillisé. La radiographie du dos du cheval constitue la modalité d’imagerie de premier choix par sa capacité diagnostique élevée. L’échographie complète la radiographie dans l’exploration des tissus mous et de la région lombaire caudale, cette dernière n’étant pas accessible par radiographie sur le cheval debout. La scintigraphie, technique plus onéreuse et plus contraignante, est envisagée pour des cas cliniques complexes. Les lésions les plus fréquemment diagnostiquées avec ces techniques d’imagerie sont représentées par les conflits et fractures des processus épineux, les arthroses synoviales intervertébrales, les spondyloses vertébrales et les lésions musculaires. La signification clinique de ces lésions doit être évaluée en considérant les signes cliniques du patient mais également sa discipline sportiv

Modulation of pro-inflammatory activation of monocytes and dendritic cells by aza-bis-phosphonate dendrimer as an experimental therapeutic agent

INTRODUCTION: Our objective was to assess the capacity of dendrimer aza-bis-phosphonate (ABP) to modulate phenotype of monocytes (Mo) and monocytes derived dendritic cells (MoDC) activated in response to toll-like receptor 4 (TLR4) and interferon γ (IFN- γ) stimulation. METHODS: Mo (n = 12) and MoDC (n = 11) from peripheral blood of healthy donors were prepared. Cells were preincubated or not for 1 hour with dendrimer ABP, then incubated with lipopolysaccharide (LPS; as a TLR4 ligand) and (IFN-γ) for 38 hours. Secretion of tumor necrosis factor α (TNFα), interleukin (IL) -1, IL-6, IL-12, IL-10 and IL-23 in the culture medium was measured by enzyme-linked immunosorbent assay (ELISA) and Cytokine Bead Array. Differentiation and subsequent maturation of MoDC from nine donors in the presence of LPS were analyzed by flow cytometry using CD80, CD86, CD83 and CD1a surface expression as markers. RESULTS: Mo and MoDC were orientated to a pro-inflammatory state. In activated Mo, TNFα, IL-1β and IL-23 levels were significantly lower after prior incubation with dendrimer ABP. In activated MoDC, dendrimer ABP promoted IL-10 secretion while decreasing dramatically the level of IL-12. TNFα and IL-6 secretion were significantly lower in the presence of dendrimer ABP. LPS driven maturation of MoDC was impaired by dendrimer ABP treatment, as attested by the significantly lower expression of CD80 and CD86. CONCLUSION: Our data indicate that dendrimer ABP possesses immunomodulatory properties on human Mo and MoDC, in TLR4 + IFN-γ stimulation model, by inducing M2 alternative activation of Mo and promoting tolerogenic MoDC

Plasmodium falciparum Adhesion on Human Brain Microvascular Endothelial Cells Involves Transmigration-Like Cup Formation and Induces Opening of Intercellular Junctions

Cerebral malaria, a major cause of death during malaria infection, is characterised by the sequestration of infected red blood cells (IRBC) in brain microvessels. Most of the molecules implicated in the adhesion of IRBC on endothelial cells (EC) are already described; however, the structure of the IRBC/EC junction and the impact of this adhesion on the EC are poorly understood. We analysed this interaction using human brain microvascular EC monolayers co-cultured with IRBC. Our study demonstrates the transfer of material from the IRBC to the brain EC plasma membrane in a trogocytosis-like process, followed by a TNF-enhanced IRBC engulfing process. Upon IRBC/EC binding, parasite antigens are transferred to early endosomes in the EC, in a cytoskeleton-dependent process. This is associated with the opening of the intercellular junctions. The transfer of IRBC antigens can thus transform EC into a target for the immune response and contribute to the profound EC alterations, including peri-vascular oedema, associated with cerebral malaria

Curing inflammatory diseases using phosphorous dendrimers

International audienceDifferent types of water-soluble phosphorous dendrimers have been synthesized and display many different biological properties. It has been shown in particular that phosphorous dendrimers of first generation functionalized with azabisphosphonate terminal functions are able to stimulate the human immune system ex vivo. These dendrimers are internalized by monocytes within a few seconds, and induce their anti-inflammatory activation. The presence of the dendrimers induces also the inhibition of the differentiation of monocytes into osteoclasts, the maturation of dendritic cells, and inhibits the proliferation of the proinflammatory CD4+ T lymphocytes. Finally, after 2–3 weeks of culture of peripheral blood mononuclear cells, amplifications by several tens of natural killer cells is observed. In view of all these properties, the influence of these azabisphosphonate-dendrimers has been tested in vivo with several animal models, against different chronic or acute inflammatory diseases, such as multiple sclerosis, rheumatoid arthritis, uveitis, and psoriasis, but also against myeloid leukemia, a hematological cancer. The hematological safety has been demonstrated in mice, as there is no platelet aggregation, no hemolysis, and no disturbance in the hematological formula. The safety of the azabisphosphonate-dendrimer has been assessed also with non-human primates (cynomolgus monkeys) which received repeated injections, as a de-risking pre-clinical test. Biochemical, hematological, and all immunological parameters in peripheral blood remained within a normal physiological range throughout the study, and all survived well. Other phosphorous dendrimers also display anti-inflammatory properties in vivo, in particular dendrimers functionalized with mannose derivatives, which prevent acute lung diseases when given orally (per os) to mice

Regulatory activity of azabisphosphonate-capped dendrimers on human CD4+ T cell proliferation enhances ex-vivo expansion of NK cells from PBMCs for immunotherapy

International audienceBACKGROUND: Adoptive cell therapy with allogenic NK cells constitutes a promising approach for the treatment of certain malignancies. Such strategies are currently limited by the requirement of an efficient protocol for NK cell expansion. We have developed a method using synthetic nanosized phosphonate-capped dendrimers allowing such expansion. We are showing here that this is due to a specific inhibitory activity towards CD4+ T cell which could lead to further medical applications of this dendrimer. METHODS: Mononuclear cells from human peripheral blood were used to investigate the immunomodulatory effects of nanosized phosphonate-capped dendrimers on interleukin-2 driven CD4+T cell expansion. Proliferation status was investigated using flow cytometry analysis of CFSE dilution and PI incorporation experiments. Magnetic bead cell sorting was used to address activity towards individual or mixed cell sub-populations. We performed equilibrium binding assay to assess the interaction of fluorescent dendrimers with pure CD4+ T cells. RESULTS: Phosphonate-capped dendrimers are inhibiting the activation, and therefore the proliferation; of CD4+ T cells in IL-2 stimulated PBMCs, without affecting their viability. This allows a rapid enrichment of NK cells and further expansion. We found that dendrimer acts directly on T cells, as their regulatory property is maintained when stimulating purified CD4+ T cells with anti-CD3/CD28 microbeads. Performing equilibrium binding assays using a fluorescent analogue, we show that the phosphonate capped-dendrimers are specifically interacting with purified CD4+ T cells. Ultimately, we found that our protocol prevents the IL-2 related expansion of regulatory T cells that would be deleterious for the activity of infused NK cells. CONCLUSION: High yield expansion of NK cells from human PBMCs by phosphonate-capped dendrimers and IL-2 occurs through the specific inhibition of the CD4+ lymphocyte compartment. Given the specificity of the interaction of dendrimers with CD4+ T cell, we hypothesize that regulatory activity may signal through a specific receptor that remains to be identified. Therefore phosphonate-capped dendrimers constitute not only tools for the ex-vivo expansion of NK cells in immunotherapy of cancers but their mode of action could also lead to further medical applications where T cell activation and proliferation need to be dampened

Anti-inflammatory and immunosuppressive activation of human monocytes by a bioactive dendrimer

International audienceThe monocyte-macrophage (MPhi) lineage can undergo different pathways of activation. The classical priming by IFN-gamma, then triggering by LPS, conducts MPhi toward proinflammatory responses, whereas the alternative activation by IL-4, IL-10, IL-13, or glucocorticoids directs them toward an anti-inflammatory, immunosuppressive phenotype. Recently, we have shown that synthetic phosphorus-containing dendrimers activate human monocytes. Here, we analyzed the gene expression of monocytes activated by an acid azabisphosphonic-capped, phosphorus-containing dendrimer by comparison with untreated monocytes. We found that 78 genes were up-regulated, whereas 62 genes were down-regulated. Analysis of these genes directed the hypothesis of an alternative-like, anti-inflammatory activation of human monocytes. This was confirmed by quantitative RT-PCR and analysis of the surface expression of specific markers by flow cytometry. Functional experiments of inhibition of CD4(+) T-lymphocyte proliferation in MLR indicated that dendrimer-activated monocytes (da-monocytes) have an immune-suppressive phenotype similar to the one induced by IL-4. Moreover, da-monocytes preferentially enhanced amplification of CD4(+) T cells, producing IL-10, an immunosuppressive cytokine. Therefore, phosphorus-containing dendrimers appear as new nanobiotools promoting an anti-inflammatory and immunosuppressive activation of human monocytes and thus, prove to be good candidates for innovative, anti-inflammatory immunotherapies

Dendrimers ended by non-symmetrical azadiphosphonate groups: Synthesis and immunological properties

International audienceThe synthesis and characterization of new series of phosphorus-containing dendrimers ended by non-symmetrical azamonophosphonates, or azadiphosphonates, or azadiphosphonic acid salts are reported. The sodium salts of the non-symmetrical azadiphosphonic dendrimers are soluble in water. Their influence towards human immune blood cells is assayed ex vivo

Frequency and route of administration in the treatment of experimental arthritis by phosphorus-based dendrimer

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