Ultrasonographic detection and assessment of the severity of Crohn's disease recurrence after ileal resection

<p>Abstract</p> <p>Background</p> <p>Recurrence and severity of Crohn's disease mucosal lesions after "curative" ileal resection is assessed at endoscopy. Intramural lesions can be detected as increased wall thickness at Small Intestine Contrast Ultrasonography (SICUS).</p> <p>Aims. To assess after ileal resection whether: 1) SICUS detects recurrence of Crohn's disease lesions, 2) the intestinal wall thickness measured at the level of ileo-colonic anastomosis predicts the severity of endoscopic lesions, 3) the extension of intramural lesions of the neo-terminal ileum is useful for grading severity of the recurrence, 4) the combined measures of wall thickness of the ileo-colonic anastomosis and of the extension of intramural lesions at level of the neo-terminal ileum may predict the endoscopic Rutgeerts score</p> <p>Methods</p> <p>Fifty eight Crohn's disease patients (M 37, age range 19-75 yrs) were prospectively submitted at 6-12 months intervals after surgery to endoscopy and SICUS for a total of 111 observations.</p> <p>Results</p> <p>Six months or more after surgery wall thickness of ileo-colonic anastomosis > 3.5 mm identified 100% of patients with endoscopic lesions (p < 0.0001). ROC curve analysis, combining wall thickness of ileo-colonic anastomosis and the extension of intramural lesions of neo-terminal ileum, discriminated (0.95) patients with, from those without, endoscopic lesions. Performing two multiple logistic regression analyses only wall thickness of ileo-colonic anastomosis and extension of neo-terminal ileum intramural lesions were significantly associated with absence or presence of endoscopic lesions. An ordinal polychotomus logistic model, considering all investigated variables, confirmed that only SICUS variables were associated with endoscopic grading of severity.</p> <p>Conclusions</p> <p>In patients submitted to ileal resection for Crohn's disease non-invasive Small Intestine Contrast Ultrasonography 1) by assessing thickness of ileo-colonic anastomosis accurately detects initial, minimal Crohn's disease recurrence, and 2) by assessing both thickness of ileo-colonic anastomosis and extension of intramural lesions of neo-terminal ileum grades the severity of the post-surgical recurrence.</p

Cholangiocytes derived from human induced pluripotent stem cells for disease modeling and drug validation.

The study of biliary disease has been constrained by a lack of primary human cholangiocytes. Here we present an efficient, serum-free protocol for directed differentiation of human induced pluripotent stem cells into cholangiocyte-like cells (CLCs). CLCs show functional characteristics of cholangiocytes, including bile acids transfer, alkaline phosphatase activity, γ-glutamyl-transpeptidase activity and physiological responses to secretin, somatostatin and vascular endothelial growth factor. We use CLCs to model in vitro key features of Alagille syndrome, polycystic liver disease and cystic fibrosis (CF)-associated cholangiopathy. Furthermore, we use CLCs generated from healthy individuals and patients with polycystic liver disease to reproduce the effects of the drugs verapamil and octreotide, and we show that the experimental CF drug VX809 rescues the disease phenotype of CF cholangiopathy in vitro. Our differentiation protocol will facilitate the study of biological mechanisms controlling biliary development, as well as disease modeling and drug screening.This work was funded by ERC starting grant Relieve IMDs (L.V., N.H.), the Cambridge Hospitals National Institute for Health Research Biomedical Research Center (L.V., N.H., F.S.), the Evelyn trust (N.H.) and the EU Fp7 grant TissuGEN (M.CDB.). FS has been supported by an Addenbrooke’s Charitable Trust Clinical Research Training Fellowship and a joint MRC-Sparks Clinical Research Training Fellowship.This is the author accepted manuscript. The final version is available from Nature Publishing Group via http://dx.doi.org/10.1038/nbt.327

Regulation and deregulation of cholangiocyte proliferation

Cholangiocytes are the epithelial cells which line the intrahepatic biliary tree, a network of interconnecting ducts of increasing diameter from the duct of Hering to the extrahepatic bile ducts [1.], [2.], [3.], [4.], [5.] and [6.]. Cholangiocytes determine the final bile composition through a series of secretory and absorptive processes regulated by a number of hormones and neuropeptides [2.], [3.], [4.] and [5.]. The intrahepatic bile ducts are the target of damage in a group of chronic cholestatic liver diseases recently classified as Vanishing Bile Duct Syndromes [4.], [7.], [8.] and [9.]. These diseases are characterized by the progressive disappearance of intrahepatic bile ducts, which leads to a severe ductopenic condition in the terminal stages [7.], [8.], [8. and [9.]. The residual bile ducts tend to proliferate as a compensatory mechanism (8). Thus, the course of these diseases is characterized by a balance between damage (loss) of bile ducts and compensatory proliferation of the residual ducts. The terminal decompensated stages are characterized by the inefficacy of proliferation to balance for the loss of intrahepatic bile ducts. Therefore, a therapeutic strategy designed to support efficacious cholangiocyte proliferation could delay progression to ductopenia. This represents a challenge for the future. The aim of this review is to focus on current knowledge of the regulation and dysregulation of cholangiocyte proliferation

Molecular identification and functional characterization of Mdr1a in rat cholangiocytes

Background & Aims: The multidrug resistance P-glycoprotein 170 gene products (mdr1a and 1b) are glycosylated plasma membrane proteins that function as adenosine triphosphate- dependent transmembrane export pumps for lipophilic xenobiotics of widely different structure. We assessed whether these P-glycoproteins ave functionally expressed in cholangiocytes. Methods: A reverse-transcription polymerase chain reaction was performed on RNA from a normal rat cholangiocyte cell line using mdr1-specific primers. Northern and Western blot analyses were performed on cholangiocytes immunoisolated from 2-week bile duct-ligated rats and cholangiocytes and isolated cholangiocyte membrane subfractions, respectively. Functional assays were performed in isolated bile duct units from bile duct-ligated rats and incubated with rhodamine 123, a P-glycoprotein substrate, with or without the P-glycoprotein inhibitors verapamil or GF120918, Results: A 400 - base pair fragment with 99% homology to the cytosolic domain of rat intestinal mdr1a (5' 1953-2350 3') was identified that hybridized to a 5.2-kilobase RNA transcript in a normal rat cholangiocyte cell line, isolated rat cholangiocytes, and ileum. Western analysis localized mdr1 to the apical membrane of cholangiocytes. Confocal microscopy showed active secretion of rhodamine 123 into the lumen of isolated bile duct units that was abolished by vanadate and P-glycoprotein competitive antagonists, verapamil and GF120918, in a dose-dependent manner. Conclusions: These findings provide the first molecular and functional evidence for the expression of mdr1a on the luminal membrane of cholangiocytes, where it may have a protective role