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Le Kremlin-Bicêtre, France

Gonzales E.,Center Hospitalier University Of Bicetre | Gonzales E.,University Paris - Sud | Grosse B.,University Paris - Sud | Cassio D.,University Paris - Sud | And 4 more authors.
Journal of Hepatology | Year: 2012

Background & Aims: Progressive familial intrahepatic cholestasis type 2 (PFIC2) is due to mutations in ABCB11 encoding the canalicular bile salt export pump (BSEP) of hepatocyte. Liver transplantation is usually required. 4-phenylbutyrate (4-PB) has been shown in vitro to retarget some selected mutated apical transporters. After an in vitro study in a hepatocellular polarized line, we tested 4-PB treatment in a child with a homozygous p.T1210P BSEP mutation. Methods: Can 10 cells were transfected with plasmids encoding wild type Bsep (Bsepwt) and mutated p.T1210P Bsep (Bsep T1210P), both tagged with GFP. Then, cells were treated with 4-PB at 37 or 27 °C, immunostained and analyzed using confocal microscopy. The child received 4-PB orally in two divided doses and BSEP liver immunostaining was performed before and after 4-PB as well as bile analysis. Results: In Can 10 cells, in contrast to Bsepwt-GFP, BsepT1210P-GFP was not detected at the canalicular membrane but in the endoplasmic reticulum. 4-PB as well as incubation at 27 °C partially corrected BsepT1210P-GFP targeting to the canalicular membrane, while combined treatments resulted in normal canalicular localization. In the child, we showed that 4-PB improved clinical and biological parameters of cholestasis and liver function. Also, canalicular expression of p.T1210P BSEP mutant was partially corrected as was biliary bile acid excretion. Conclusions: The results illustrate for the first time the therapeutic potential of a clinically approved chaperone drug in a selected patient with PFIC2 and support that bile secretion improvement might be due to the ability of 4-PB to retarget mutated BSEP. © 2012 European Association for the Study of the Liver. Source


Dubory A.,Laboratoire Detude Of La Microcirculation | Dubory A.,Bicetre Universitary Hospital | Laemmel E.,Laboratoire Detude Of La Microcirculation | Badner A.,University of Toronto | And 6 more authors.
Journal of Visualized Experiments | Year: 2015

Reduced spinal cord blood flow (SCBF) (i.e., ischemia) plays a key role in traumatic spinal cord injury (SCI) pathophysiology and is accordingly an important target for neuroprotective therapies. Although several techniques have been described to assess SCBF, they all have significant limitations. To overcome the latter, we propose the use of real-time contrast enhanced ultrasound imaging (CEU). Here we describe the application of this technique in a rat contusion model of SCI. A jugular catheter is first implanted for the repeated injection of contrast agent, a sodium chloride solution of sulphur hexafluoride encapsulated microbubbles. The spine is then stabilized with a custom-made 3D-frame and the spinal cord dura mater is exposed by a laminectomy at ThIX-ThXII. The ultrasound probe is then positioned at the posterior aspect of the dura mater (coated with ultrasound gel). To assess baseline SCBF, a single intravenous injection (400 μl) of contrast agent is applied to record its passage through the intact spinal cord microvasculature. A weight-drop device is subsequently used to generate a reproducible experimental contusion model of SCI. Contrast agent is re-injected 15 min following the injury to assess post-SCI SCBF changes. CEU allows for real time and in-vivo assessment of SCBF changes following SCI. In the uninjured animal, ultrasound imaging showed uneven blood flow along the intact spinal cord. Furthermore, 15 min post-SCI, there was critical ischemia at the level of the epicenter while SCBF remained preserved in the more remote intact areas. In the regions adjacent to the epicenter (both rostral and caudal), SCBF was significantly reduced. This corresponds to the previously described “ischemic penumbra zone”. This tool is of major interest for assessing the effects of therapies aimed at limiting ischemia and the resulting tissue necrosis subsequent to SCI. © 2015 Journal of Visualized Experiments. Source


Claperon A.,French Institute of Health and Medical Research | Claperon A.,University Pierre and Marie Curie | Debray D.,French Institute of Health and Medical Research | Debray D.,University Pierre and Marie Curie | And 12 more authors.
Clinics and Research in Hepatology and Gastroenterology | Year: 2013

Aim: Ezrin and radixin are actin-binding proteins that contribute to the integrity of epithelia. Abnormalities of bile secretion occur primarily in cholestatic liver diseases and are associated with changes in cell cytoskeleton. Expression of these proteins during liver development and in cholestatic liver diseases remains poorly investigated. Methods: Ezrin and radixin expression was analyzed in fetal, adult and pediatric cholestatic human liver (i.e. biliary atresia, sclerosing cholangitis) by immunohistochemistry. Results: In adult and fetal livers, ezrin was expressed exclusively in the cells of the biliary lineage (i.e. biliary epithelial cells and ductal cells) whereas radixin was located not only in hepatocytes but also in cells of the biliary lineage. In the lobule of mature livers, radixin displayed a zonal distribution with predominant expression in the periportal region. In cholestatic diseases, both proteins were expressed in cells of the ductular reaction. An aberrant expression of ezrin was detected in hepatocytes of cirrhotic nodules with a CK7-positive pattern and in malignant hepatocytes in a course of cholestatic disease toward cancer. Conclusions: Among the components of the liver epithelial cells, ezrin was exclusively expressed in biliary phenotype cells, while radixin was found in biliary and hepatocytic lineages, with a periportal zonal expression. In cholestatic diseases, ezrin was expressed in hepatocytes supporting the appearance of a biliary phenotype. © 2013 . Source

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