In vitro validation of duct differentiation in developing embryonic mouse pancreas

BACKGROUND: Early embryonic pancreatic epithelia have the capacity for either endocrine or exocrine lineage commitment. Recent studies demonstrated the pluripotential nature of these undifferentiated cells. Isolated pancreatic epithelia grown under the renal capsule formed primarily islets. However, when these same epithelia were grown in a basement-membrane-rich gel (Matrigel) they formed mostly ducts. Currently, there is no model for in vitro pancreatic duct formation and therefore, the mechanism of duct morphogenesis has never been described. The purpose of this study was to provide such a model by characterizing the expression of two duct markers, carbonic anhydrase II (CAII) and the cystic fibrosis transmembrane conductance regulator (CFTR), in isolated undifferentiated pancreatic epithelia grown in vitro. MATERIALS AND METHODS: We microdissected embryonic pancreases at Embryonic Days (E)9.5-11.5 and performed RT-PCR for CAII and CFTR on E9.5 whole pancreases, E10. 5 and E11.5 epithelia, as well as E11.5 epithelia grown for 7 days in Matrigel. Next we performed in situ hybridization for CAII and CFTR and immunohistochemistry for CAII on E11.5 epithelia grown for 7 days in Matrigel. RESULTS: Early, undifferentiated embryonic pancreatic epithelium does not express CAII and CFTR by RT-PCR. When E11.5 epithelia were grown for 7 days in Matrigel, however, gene expression for both markers is upregulated as ducts form. Furthermore, CAII was seen by IHC and both CAII and CFTR were seen by in situ hybridization in the ducts after 7 days in Matrigel. CONCLUSIONS: These data validate our in vitro system as a model for studying the mechanism of normal pancreatic duct differentiation and may potentially help us to understand the faulty mechanism involved in pancreatic ductal carcinogenesis.     

Induction of immune tolerance in patients with hemophilia A and inhibitors treated with porcine VIIIC by home therapy

Home therapy with porcine factor VIIIC was safe and effective when administered to five hemophilic patients over periods of 8 1/2, 6, 4, 3 1/2, and 2 years. No significant transfusion reactions occurred. Before treatment with porcine factor VIIIC, all five had high-level, high- responding anti-human VIIIC inhibitors initially lacking anti-porcine factor VIIIC activity. Although specific anti-porcine VIIIC inhibitors arose in all patients, these were generally transient, and only one patient became refractory to treatment. We believe that porcine factor VIIIC is the treatment of choice in patients whose inhibitors do not cross-react. All five patients lost their original anti-human VIIIC inhibitors after starting treatment with porcine VIIIC, permitting the reintroduction of human VIIIC in three of them. There has been no recurrence of anti-human VIIIC inhibitor activity during 2 to 3 years of regular treatment with human VIIIC in these patients. This suggests that tolerance to human VIIIC has arisen as a result of treatment with porcine VIIIC. Porcine VIIIC may have a role in the desensitization of some factor VIIIC inhibitor patients.     

Locus assignment of two alpha-globin structural mutants from the Caribbean basin: alpha Fort de France (alpha 45 Arg) and alpha Spanish Town (alpha 27 Val)

Two alpha-globin structural mutants were mapped to their encoding loci by in vitro translation of hybrid-selected alpha 1- and alpha 2-globin mRNA. The more highly expressed mutant, alpha Spanish Town (alpha 27Val), is encoded at the alpha 2 locus and the less expressed mutant, alpha Fort de France (alpha 45Arg), is encoded at the alpha 1 locus. These results further define the distribution of alpha-globin structural mutations within the alpha-globin gene cluster and substantiate the dominant role of the alpha 2-globin locus in alpha- globin expression.     

Seroprevalence of hepatitis B and C viruses in moderate and severe COVID-19 inpatients: A cross-sectional study at a referral center in Mexico

Introduction and ObjectivesThe emergence of SARS-CoV-2, which causes the coronavirus disease (COVID-19) has caused a great impact on healthcare systems worldwide, including hepatitis B and C viruses screening and elimination programs. The high number of COVID-19 hospitalizations represent a great opportunity to screen patients for hepatitis B virus (HBV) and hepatitis C virus (HCV), which was the aim of this study.Material and MethodsCross-sectional, retrospective study performed between April 2020 and 20201 at a referral center in Mexico dedicated to the care of adults with severe/critical COVID-19. We retrieved clinical, demographic, and laboratory results from each patient´s medical records, including antibodies against HCV (anti-HCV), HBV surface antigen (HBsAg), antibodies against the HBV core antigen (anti-HBcAg), and antibodies against HBsAg (anti-HBsAg).ResultsOut of 3620 patients that were admitted to the hospital, 24 (0.66%), 4 (0.11%), and 72 (1.99%) tested positive for anti-HCV, HBsAg, and anti-HBcAg, respectively. Of all seronegative patients, 954 (27%) had undetectable anti-HBsAg and 401 (12%) had anti-HBsAg at protective levels. Blood transfusion was the most relevant risk factor. Only 9.7% of the anti-HBc positive, 25% of the HBsAg positive, and 52% of the anti-HCV positive were aware of their serological status.ConclusionsIn this study we found a prevalence of anti-HCV of 0.66%, HBsAg in 0.11%, and isolated anti-HBcAg in 1.99%. We also found that HBV vaccination coverage has been suboptimal and needs to be reinforced. This study gave us a trustworthy insight of the actual seroprevalence in Mexico, which can help provide feedback to the Hepatitis National Elimination Plan.     

Retinoid signaling directs secondary lineage selection in pancreatic organogenesis

BACKGROUND/PURPOSE: Retinoid signaling plays an important role in many differentiation pathways. Retinoid signaling has been implicated in the induction of differentiation by pancreatic ductal cancer cell lines and in patients with pancreatic cancer. The authors wished to better understand the role of retinoid signaling in pancreatic development. METHODS: Embryonic pancreas was harvested from mice at serial gestational ages and immunohistochemical analysis was performed for retinoic acid receptors (RAR-alpha, RAR-beta, RAR-gamma), and retinoid X receptors (RXR-alpha, RXR-beta, and RXR-gamma). Also, early embryonic pancreases were cultured for 7 days with exogenous 9-cis retinoic acid (9cRA) or all-trans retinoic acid (atRA) and analyzed histologically and immunohistochemically. RESULTS: Retinoid receptors were expressed in a lineage-specific distribution, with stronger expression for many in the exocrine compartment. The receptors were not often expressed until late gestation. Exogenous 9cRA induced predominantly ducts instead of acini, plus more mature endocrine (islet) architecture. Exogenous atRA induced predominantly acini instead of ducts, with no apparent endocrine effect. CONCLUSIONS: Retinoids may have an important role in pancreatic differentiation, with a particular effect on secondary lineage selection between ductal and acinar phenotype. Because the control of ductal versus acinar differentiation has been implicated strongly in the pathogenesis of pancreatic ductal carcinoma, these results may lay the groundwork for studies in the mechanism of induced differentiation of pancreatic ductal cancer by retinoids.