Reconstruction of the mouse extrahepatic biliary tree using primary human extrahepatic cholangiocyte organoids.

The treatment of common bile duct (CBD) disorders, such as biliary atresia or ischemic strictures, is restricted by the lack of biliary tissue from healthy donors suitable for surgical reconstruction. Here we report a new method for the isolation and propagation of human cholangiocytes from the extrahepatic biliary tree in the form of extrahepatic cholangiocyte organoids (ECOs) for regenerative medicine applications. The resulting ECOs closely resemble primary cholangiocytes in terms of their transcriptomic profile and functional properties. We explore the regenerative potential of these organoids in vivo and demonstrate that ECOs self-organize into bile duct-like tubes expressing biliary markers following transplantation under the kidney capsule of immunocompromised mice. In addition, when seeded on biodegradable scaffolds, ECOs form tissue-like structures retaining biliary characteristics. The resulting bioengineered tissue can reconstruct the gallbladder wall and repair the biliary epithelium following transplantation into a mouse model of injury. Furthermore, bioengineered artificial ducts can replace the native CBD, with no evidence of cholestasis or occlusion of the lumen. In conclusion, ECOs can successfully reconstruct the biliary tree, providing proof of principle for organ regeneration using human primary cholangiocytes expanded in vitro.

Association of a low-frequency variant in HNF1A with type 2 diabetes in a Latino population.

IMPORTANCE: Latino populations have one of the highest prevalences of type 2 diabetes worldwide. OBJECTIVES: To investigate the association between rare protein-coding genetic variants and prevalence of type 2 diabetes in a large Latino population and to explore potential molecular and physiological mechanisms for the observed relationships. DESIGN, SETTING, AND PARTICIPANTS: Whole-exome sequencing was performed on DNA samples from 3756 Mexican and US Latino individuals (1794 with type 2 diabetes and 1962 without diabetes) recruited from 1993 to 2013. One variant was further tested for allele frequency and association with type 2 diabetes in large multiethnic data sets of 14,276 participants and characterized in experimental assays. MAIN OUTCOME AND MEASURES: Prevalence of type 2 diabetes. Secondary outcomes included age of onset, body mass index, and effect on protein function. RESULTS: A single rare missense variant (c.1522G>A [p.E508K]) was associated with type 2 diabetes prevalence (odds ratio [OR], 5.48; 95% CI, 2.83-10.61; P = 4.4 × 10(-7)) in hepatocyte nuclear factor 1-α (HNF1A), the gene responsible for maturity onset diabetes of the young type 3 (MODY3). This variant was observed in 0.36% of participants without type 2 diabetes and 2.1% of participants with it. In multiethnic replication data sets, the p.E508K variant was seen only in Latino patients (n = 1443 with type 2 diabetes and 1673 without it) and was associated with type 2 diabetes (OR, 4.16; 95% CI, 1.75-9.92; P = .0013). In experimental assays, HNF-1A protein encoding the p.E508K mutant demonstrated reduced transactivation activity of its target promoter compared with a wild-type protein. In our data, carriers and noncarriers of the p.E508K mutation with type 2 diabetes had no significant differences in compared clinical characteristics, including age at onset. The mean (SD) age for carriers was 45.3 years (11.2) vs 47.5 years (11.5) for noncarriers (P = .49) and the mean (SD) BMI for carriers was 28.2 (5.5) vs 29.3 (5.3) for noncarriers (P = .19). CONCLUSIONS AND RELEVANCE: Using whole-exome sequencing, we identified a single low-frequency variant in the MODY3-causing gene HNF1A that is associated with type 2 diabetes in Latino populations and may affect protein function. This finding may have implications for screening and therapeutic modification in this population, but additional studies are required.

[Evaluation of twenty-three episodes of acute thoracic syndrome in patients with sickle cell anemia]. / Evaluación de veintitrés episodios de síndrome torácico agudo en pacientes con drepanocitosis.

INTRODUCTION: Acute thoracic syndrome (pneumonia and/or lung infarction) is a significant cause of morbidity and mortality in sickle cell anemia. OBJECTIVE: To review the clinical manifestations, management and outcome of episodes of acute thoracic syndrome in our hospital. METHODS: We performed a retrospective review of all the episodes of acute thoracic syndrome diagnosed at our center in patients younger than 18 years of age with sickle cell anemia. Clinical, laboratory and radiological findings, outcome and treatment were analyzed. Data from patients < 3 years and > 3 years of age were compared (Fisher's exact test and the Mann-Whitney U test). RESULTS: Twenty-three episodes of acute thoracic syndrome were evaluated in eight out of 12 patients with sickle cell anemia followed-up in our hospital. These episodes represented 36 % of the total time of admission in these patients. The most frequent cause was infection. The most frequent symptoms were fever (87 %), cough (61 %) and cold (35 %) symptoms. Seventy-four percent of the patients were not diagnosed at admission, either because the chest X-ray was normal (52 %) or because it was not performed (22 %) due to the absence of pulmonary manifestations. Patients aged more than 3 years old had more severe episodes, with greater clinical compromise and radiological involvement and increased use of analgesia. Transfusions were administered in 65 % of the episodes and in five patients (> 3 years) a partial exchange transfusion was performed. In five patients corticoid treatment was associated with febrile relapses. CONCLUSIONS: Acute thoracic syndrome is frequent in sickle cell disease and is more severe in children older than 3 years. Its diagnosis requires a high index of suspicion, due to multiple forms of clinical presentations and normal chest radiology at admission.