Publications by authors named "Lieubeau B"

Article Synopsis
  • - Diabetes is a significant public health issue influenced by genetic and environmental factors, with some models, like monogenic forms in mice, helping to understand the disease better.
  • - A study involving NOD mice with a specific genetic mutation (Akt2 invalidation) showed that these mice developed severe hyperglycemia early on, particularly in males, without the influence of an autoimmune response.
  • - The research found that the HYP mice exhibited hyperinsulinemia before hyperglycemia and had lower insulin levels in their pancreas compared to NOD mice, suggesting that failure of beta cells is a key factor in the development of diabetes.
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Hair cortisol is a stress indicator and could be used to assess the pigs' exposure to stressors in the weeks/months prior to non-invasive hair sampling. The main aim of this study was to describe the hair cortisol concentration (HCC) variability between individuals within a batch, between farms and between batches within a farm. The secondary aim was to determine how the number of sampled pigs influences the characterization of HCC within a batch.

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Nowadays, most pigs are raised indoors, on intensive farms providing a poor environment. In these conditions, the risk of the occurrence of damaging behaviours is high, with dramatic consequences for animal health and welfare as well as economic losses for farmers. Early-life conditions may predispose individuals to develop damaging behaviours later in life.

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Background: Multiple antigenic stimulations are crucial to immune system training during early post-natal life. These stimulations can be either due to commensals, which accounts for the acquisition and maintenance of tolerance, or to pathogens, which triggers immunity. In pig, only few works previously explored the influence of natural exposition to pathogens upon immune competence.

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Background: Muscular dystrophies (MDs) are inherited diseases in which a dysregulation of the immune response exacerbates disease severity and are characterized by infiltration of various immune cell types leading to muscle inflammation, fiber necrosis and fibrosis. Immunosuppressive properties have been attributed to mesenchymal stem cells (MSCs) that regulate the phenotype and function of different immune cells. However, such properties were poorly considered until now for adult stem cells with myogenic potential and advanced as possible therapeutic candidates for MDs.

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Background: The incidence of inflammatory bowel disease (IBD) is increasing worldwide, emphasizing the need of relevant models, as dogs spontaneously affected by IBD may be, for better knowledge of the disease's physiopathology.

Methods: We studied 22 client-owned dogs suffering from IBD without protein loss and 14 control dogs. Biopsies were obtained from the duodenum, ileum, and colon.

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Article Synopsis
  • The study investigates how selecting pigs based on their HPA axis activity can enhance animal robustness and health, aiming to align with sustainable farming practices.
  • Researchers conducted an experiment with Large White pigs, comparing hematologic and immune parameters between low and high HPA responders at six weeks of age.
  • Results showed that high HPA pigs had better immune cell counts and responses, but by eight weeks, both groups showed similar immune parameters, suggesting high cortisol levels in HPA pigs don't harm their immune system.
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Features of intensive farming can seriously threaten pig homeostasis, well-being and productivity. Disease tolerance of an organism is the adaptive ability in preserving homeostasis and at the same time limiting the detrimental impact that infection can inflict on its health and performance without affecting pathogen burden . While disease resistance (DRs) can be assessed measuring appropriately the pathogen burden within the host, the tolerance cannot be quantified easily.

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Background: Canine MuStem cells have demonstrated regenerative efficacy in a dog model of muscular dystrophy, and the recent characterization of human counterparts (hMuStem) has highlighted the therapeutic potential of this muscle-derived stem cell population. To date, these cells have only been generated in research-grade conditions. However, evaluation of the clinical efficacy of any such therapy will require the production of hMuStem cells in compliance with good manufacturing practices (GMPs).

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After intra-arterial delivery in the dystrophic dog, allogeneic muscle-derived stem cells, termed MuStem cells, contribute to long-term stabilization of the clinical status and preservation of the muscle regenerative process. However, it remains unknown whether the human counterpart could be identified, considering recent demonstrations of divergent features between species for several somatic stem cells. Here, we report that MuStem cells reside in human skeletal muscle and display a long-term ability to proliferate, allowing generation of a clinically relevant amount of cells.

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Adrenergic receptor agonists and antagonists are extensively used as drugs in medicine for a broad spectrum of indications. We examined the consequences of β2-adrenergic stimulation of murine dendritic cells (DCs) on CD4 T cell activation. We demonstrated in vitro that treatment of LPS-matured DCs with the β2-agonist salbutamol reduced their ability to trigger OT-II T cell proliferation specific for ovalbumin antigen.

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The cross-talk between sympatho-adreno-medullar axis and innate immunity players was mainly studied in rodents. In intensive husbandry, pigs are exposed to multiple stressors inducing repeated releases of catecholamines that bind to adrenoreceptors (AR) on target cells. Among adrenoreceptors, the β2-AR is largely expressed by immune cells including macrophages.

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Article Synopsis
  • Pig husbandry involves intensive breeding, exposing piglets to stress from events like early weaning and mixing, which can weaken their immune systems and lead to increased antibiotic use.
  • This study focused on how acute social stress affects the immune response of piglets selected for their differing HPA axis activity, showing stressed piglets had higher cortisol levels and altered immune responses.
  • Findings suggest that high-responding piglets may have better immune responses and resistance to pathogens compared to low-responders, indicating that selecting for robustness could improve overall pig health in stressful environments.
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In humans, CXCR1 and CXCR2 are two homologous proteins that bind ELR+ chemokines. Both receptors play fundamental roles in neutrophil functions such as migration and reactive oxygen species production. Mouse Cxcr1 and Cxcr2 genes are located in an insulin-dependent diabetes genetic susceptibility locus.

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Background: The bone marrow may be involved in human atopic diseases, as shown by the release of CD34+ cells into the peripheral blood.

Hypothesis/objectives: The aim was to determine the numbers of CD34+ cells in atopic dogs.

Animals: The following three groups of dogs were studied: 27 dogs with nonfood-induced atopic dermatitis (NFICAD); 16 dogs with nonallergic inflammatory diseases; and 13 healthy control dogs.

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Gene silencing approaches have the potential to become a powerful curative tool for a variety of monogenic diseases caused by gain-of-function mutations. Classical osteogenesis imperfecta (OI), a dominantly inherited bone dysplasia, is characterized in its more severe forms by synthesis of structurally abnormal type I collagen, which exerts a negative effect on extracellular matrix. Specific suppression of the mutant (Mut) allele would convert severe OI forms to the mild type caused by a quantitative defect in normal collagen.

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Duchenne muscular dystrophy (DMD) is a genetic progressive muscle disease resulting from the lack of dystrophin and without effective treatment. Adult stem cell populations have given new impetus to cell-based therapy of neuromuscular diseases. One of them, muscle-derived stem cells, isolated based on delayed adhesion properties, contributes to injured muscle repair.

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We have previously demonstrated that CD34(+) cells isolated from fetal mouse muscles are an interesting source of myogenic progenitors. In the present work, we pinpoint the tissue location of these CD34(+) cells using cell surface and phenotype markers. In order to identify the myogenic population, we next purified different CD34(+) subsets, determined their expression of relevant lineage-related genes, and analyzed their differentiation capacities in vitro and in vivo.

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Cyclophosphamide (CTX) was previously shown to induce the recruitment of immunosuppressive myeloid cells in mouse. In the non-obese diabetic (NOD) mouse, which develops spontaneously type I diabetes, CTX is widely known to accelerate the autoimmune process. Our data demonstrated that CTX actually did mobilize an immunosuppressive myeloid CD11b(+) Ly-6G(-) population in the NOD mouse spleen in addition to a well-identified neutrophil CD11b(+) Ly-6G(+) population.

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In recent years, several investigators have shown that transfer of dendritic cells (DC) prevents diabetes development in non-obese diabetic (NOD) mice. Accumulating evidences showing that DC cultured in medium containing fetal calf serum (FCS) can induce a dominant unspecific immune response in tumor models after i.v.

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Establishment and maintenance of transgenic mouse strains require being able to distinguish homozygous from heterozygous animals. To date, the developed real-time quantitative PCR techniques are often complicated, time-consuming and expensive. Here, we propose a very easy and rapid method with a simple data analysis to determine zygosity in transgenic mice.

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In vitro approaches have extensively been developed to study reparative dentinogenesis. While dental pulp is a source of unidentified progenitors able to differentiate into odontoblast-like cells, we investigated the effect of two media; MEM (1.8 mM Ca and 1 mM Pi) and RPMI 1640 (0.

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Regenerative dental pulp strategies require the identification of precursors able to differentiate into odontoblast-like cells that secrete reparative dentin after injury. Pericytes have the ability to give rise to osteoblasts, chondrocytes, and adipocytes, a feature that has led to the suggestion that odontoblast-like cells could derive from these perivascular cells. In order to gain new insights into this hypothesis, we investigated the effects of dexamethasone (Dex), a synthetic glucocorticoid employed to induce osteogenic differentiation in vitro, in a previously reported model of human dental pulp cultures containing pericytes as identified by their expression of smooth muscle actin (SMA) and their specific ultrastructural morphology.

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For physiological and practical reasons the dog is a large animal model used increasingly to study the pathogenesis of human diseases and new therapeutic approaches, in particular for immune disorders. However, some immunological resources are lacking in this model, especially concerning dendritic cells. The aim of our study was to develop an efficient method to generate dendritic cells (DC) in vitro from dog peripheral blood mononuclear cells (PBMC) and to characterize their functional, structural and ultrastructural properties.

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We have demonstrated previously the ability of apoptotic cells to prime a functional immune response using an i.p. vaccination protocol with apoptotic cells and interleukin 2, before injecting a lethal dose of tumor cells into syngeneic rats.

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