Vitamine A et Organogenèse Rénale (identification de nouveaux marqueurs du développement rénal)

Le développement du métanéphros repose sur des interactions moléculaires complexes entre le bourgeon urétéral et le mésenchyme métanéphrique, aboutissant à la formation des canaux collecteurs pour le premier et à la conversion en néphrons du second. La vitamine A par l'intermédiaire de son métabolite actif l'acide rétinoïque, contrôle de manière dose dépendante l'organogenèse rénale. Le but de ce travail de thèse a été d'une part, d'analyser lors d e la néphrogenèse, la répartition cellulaire des enzymes impliquées dans la synthèse (Aldéhyde deshydrogénases Aldh1a1 à 4) et la dégradation de l'acide rétinoïque (Cytochrome P450 26A1 et Bl, Cyp26A1 et B1) et d'autre part, de rechercher de gène différentiellement exprimes après stimulation in vitro de la n éphrogenèse par l'acide rétinoïque. Ainsi nous avons identifié trois gènes, Mortaline-2, Myotrophine et Attractine-like, comme étant de nouveaux marqueurs du développement rénal et ayant une expression sensible à l'acide rétinoïque.PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

Diode laser surgery in a 2-year- old doe with progesterone receptor free vaginal varicose veins

peer reviewedGenital vascular abnormalities described in rabbits are a rare condi-tion and almost exclusively endometrial veinous aneurysms. They are incidental findings unless they are ruptured leading to a life-threatening vaginal bleeding. A 2-year-old female intact Bleu de Ham rabbit was presented with a 2 cm soft purple mass protruding from the vulva and a vaginitis. Under general anaestesia (dexmedetomidine, ketamine, mi-dazolam intramuscularly, propofol, fentanyl intravenously and isoflu-rane gas via an endotracheal tube), this mass and a second one present cranially in the vagina were resected through a ventral episiotomy. A partial thickness incision was made around their pedicles with a surgi-cal diode laser. The doe received meloxicam, buprenorphine, tramadol, metoclopramide, aluminium phosphate post surgery. Trimetoprim sul-famide was added because of purulent rhinitis. Six months after mass removal, the doe was ovariohysterectomized, and no sign of recurrence was observed. The animal was euthanized 6 months later because of gastric stasis, and recurrences were present in the vagina. At histologi-cal examination, both the primary and the recurring lesions were di-agnosed as voluminous varicose veins, and the only uterine anomaly that was found was cystic endometrial hyperplasia. Immunochemistry failed to identify progesterone receptors on the vaginal lesions. Recurrence after ovariohysterectomy and the absence of progesterone receptors in this case suggest that sex hormones are not involved in the etiopathogenesis of vaginal varicose veins in rabbits while they are strongly suspected in vulvar varicose veins in pregnant women. This is the first detailed report of a vaginal localization of varicose veins in a female rabbit and their surgical removal with the aid of a diode laser

In vivo expression of podocyte slit diaphragm-associated proteins in nephrotic patients with NPHS2 mutation

In vivo expression of podocyte slit diaphragm-associated proteins in nephrotic patients with NPHS2 mutation.BackgroundMutations in NPHS2, encoding podocin, are a prevalent cause of autosomal-recessive steroid-resistant nephrotic syndrome (SRNS). Podocin is a protein associated with the slit diaphragm that interacts with nephrin and CD2-associated protein (CD2AP) within lipid rafts.MethodsUsing renal biopsies of six patients, we analyzed the in vivo consequences of different types of NPHS2 mutations on (1) the podocyte expression and distribution of podocin using in situ hybridization and immunohistology and (2) the distribution of related podocyte proteins and glomerular extracellular matrix components.ResultsIn two patients with homozygous 855_856delAA or 419delG mutation, absence of podocyte labeling with the antibodies against the C-terminal domain contrasted with the normal expression of the N-terminal domain of the protein along the glomerular basement membrane (GBM). In patients carrying compound heterozygous mutations or variants (R168S/467_468insT, R138Q/V180M, and R291W/R229Q), or single heterozygous 976_977insA, podocin transcription appeared unchanged but the distribution of the protein was modified. Podocin was restricted to the podocyte body in the patient carrying the R168S/467_468insT mutation whereas strong immunolabeling of the podocyte body was associated with discrete labeling along the GBM in the three others. In all cases, podocin defect was associated with changes in the distribution of nephrin, CD2AP, and α-actinin: the proteins were mainly detected in the podocyte body, with mild expression along the GBM. There were no detectable changes in the distribution of other podocyte proteins or glomerular extracellular matrix components.ConclusionNPHS2 mutations result in profound alteration of podocin expression and/or distribution. Secondary changes in the distribution of nephrin, CD2AP, and α-actinin are additional evidences for the scaffolding role of podocin in the organization of the slit diaphragm

Met and the epidermal growth factor receptor act cooperatively to regulate final nephron number and maintain collecting duct morphology

Ureteric bud (UB) branching during kidney development determines the final number of nephrons. Although hepatocyte growth factor and its receptor Met have been shown to stimulate branching morphogenesis in explanted embryonic kidneys, loss of Met expression is lethal during early embryogenesis without obvious kidney abnormalities. Metfl/fl;HoxB7-Cre mice, which lack Met expression selectively in the UB, were generated and found to have a reduction in final nephron number. These mice have increased Egf receptor expression in both the embryonic and adult kidney, and exogenous Egf can partially rescue the branching defect seen in kidney explants. Metfl/fl;HoxB7-Cre;wa-2/wa-2 mice, which lack normal Egfr and Met signaling, exhibit small kidneys with a marked decrease in UB branching at E14.5 as well as a reduction in final glomerular number. These mice developed progressive interstitial fibrosis surrounding collecting ducts with kidney failure and death by 3-4 weeks of age. Thus, in support of previous in vitro findings, Met and the Egf receptor can act cooperatively to regulate UB branching and mediate maintenance of the normal adult collecting duct

The protective role of macrophage migration inhibitory factor in acute kidney injury after cardiac surgery

Acute kidney injury (AKI) represents the most frequent complication after cardiac surgery. Macrophage migration inhibitory factor (MIF) is a stress-regulating cytokine that was shown to protect the heart from myocardial ischemia-reperfusion injury, but its role in the pathogenesis of AKI remains unknown. In an observational study, serum and urinary MIF was quantified in 60 patients scheduled for elective conventional cardiac surgery with the use of cardiopulmonary bypass. Cardiac surgery triggered an increase in MIF serum concentrations, and patients with high circulating MIF (>median) 12 hours after surgery had a significantly reduced risk of developing AKI (relative risk reduction, 72.7%; 95% confidence interval, 12 to 91.5%; P = 0.03). Experimental AKI was induced in wild-type and Mif-/- mice by 30 min of ischemia followed by 6 or 24 hours of reperfusion, or by rhabdomyolysis. Mif-deficient mice exhibited increased tubular cell injury, increased regulated cell death (necroptosis and ferroptosis), and enhanced oxidative stress. Therapeutic administration of recombinant MIF after ischemia-reperfusion in mice ameliorated AKI. In vitro treatment of tubular epithelial cells with recombinant MIF reduced cell death and oxidative stress as measured by glutathione and thiobarbituric acid reactive substances in the setting of hypoxia. Our data provide evidence of a renoprotective role of MIF in experimental ischemia-reperfusion injury by protecting renal tubular epithelial cells, consistent with our observation that high MIF in cardiac surgery patients is associated with a reduced incidence of AKI.status: publishe

Teaching biosecurity standard operating procedures in the Veterinary Faculty, University of Liege, using eCampus learning platform

peer reviewedIntroduction and aim: In veterinary medicine, biosecurity relies on the implementation and respect of procedures that reduce the risk of the introduction and spread of pathogens. The concept has recently attained great importance in veterinary medicine, especially in veterinary teaching hospitals, with regard to the accreditation processes of Veterinary Education Establishments in Europe. Indeed, standard operating procedures (SOPs) and practices regarding hygiene, biosecurity and infection control were implemented. The main objective of the study was to assess the usefulness of observations in estimating the compliance of veterinary students with biosecurity measures implemented in the necropsy room of a Faculty of Veterinary Medicine (n = 122 observations) and in a private slaughterhouse (n = 56 observations) in Belgium, during day sessions of practical work. Materials and methods: Checklists compiling the biosecurity rules to apply in both contexts were established (31 rules were considered for the necropsy room and 35 for the slaughterhouse). Observations were performed by a single person to ensure standardisation. Results: The level of compliance with biosecurity rules was intermediate and reached 42% vs. 37% for the necropsy room and the slaughterhouse, respectively. No significant difference was observed between these compliance rates. Conclusions: These results are comparable to the estimations reported in human medicine with a compliance rate reported between 33% and 54% for the therapeutic compliance and long-term follow-up of preventive recommendations by patients (Haynes et al., 1979). Increasing staff supervision of students and increasing awareness through education should be encouraged. Concomitant with this study, a biosecurity e-learning platform for veterinary students was implemented in Belgium, at the University of Liege. The follow-up of observations through time could be used to assess the evolution of compliance with biosecurity measures