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OC12 Candidate stem cell niches in the peribiliary glands (PBGs) of human extra hepatic bile ducts (hEHBDs)
Abstracts of the A.I.S.F. Monothematic Conference 2010 / Digestive and Liver Disease 42S (2010), S311–S318 the main site of ADMA metabolism. The goals of our study were: first, to investigate whether ADMA and SDMA were detectable in bile; second, the effects of ischemia-reperfusion (I/R) injury on biliary ADMA and SDMA excretion; third, to evaluate whether the biliary concentration of ADMA and SDMA could be considered as a marker of liver damage. Methods: Male Wistar rats were subjected to 30-min partial hepatic ischemia by clamping the hepatic artery and the portal vein. After 60-min reperfusion, plasma and bile samples were collected and the concentrations of ADMA, SDMA and arginine (Arg) were measured by HPLC equipped with a fluorescence detector. AST, ALT and Alkaline Phosphatase (AP) levels in serum and bile were also determined. Results: The ADMA, SDMA and Arg levels detected in plasma confirmed data previously reported in rats. Both forms of methylarginenes and Arg were also detected in bile. After I/R injury, a decrease in Arg concentration and no changes in plasma ADMA and SDMA levels were found. On the contrary, a significant increase of ADMA and SDMA was observed in bile at the end of reperfusion associated to a decrease in Arg content. A marked increase in AST, ALT and AP levels in serum and bile after I/R confirmed both hepatocyte and cholangiocyte damage. Conclusions: This study demonstrated, for the first time, that the liver is responsible for the biliary excretion of ADMA and SDMA in unchanged form. In addition an increase in ADMA and SDMA biliary excretion occurs during I/R and both forms of methylarginenes could be considered as a marker of liver injury. These data also allow a step forward in the understanding of the mechanisms involved in the control of ADMA and SDMA levels.
OC12 Candidate stem cell niches in the peribiliary glands (PBGs) of human extra hepatic bile ducts (hEHBDs) G. Carpino 1,2 , V. Cardinale 1 , Y. Wang 3, , M. Gatto 1 , A. Torrice 1 , R. Semeraro 1 , C. Napoli 1 , R. Gentile 1 , G. Mennini 1 , M. Rossi 1 , P.B. Berloco 1 , L.M. Reid 3 , D. Alvaro 1 , E. Gaudio 1 1 “Sapienza” University of Rome, Rome, Italy; 2 University of Rome “Foro Italico”, Rome, Italy; 3 University of North Carolina, Chapel Hill, NC, USA
Background and aim: A stem cells niche has been identified within the human intrahepatic bile duct system at the level of canals of Hering. PBGs are
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tubulo-alveolar glands, found deep within the walls of hEHBDs. Until now, the functions of the PBGs have not been known other than mucous production. However, proliferation of cells within PBGs, observed in chronic diseases or associated with malignancies, follows a pattern similar to that with typical stem cell compartment activation. Our aims are to evaluate if PBGs could represent a stem cell niche within the EHBDs and if the sites of higher density of PBGs overlap with known sites of malignancies. Materials and methods: Common hepatic duct, cystic duct, gallbladder and main bile duct were obtained from normal human adult livers and hepatopancreatic ampulla from pancreas. A survey was done (n= 5 human biliary trees) defining the numbers of PBGs by histology, by marker profiles utilizing immunohistochemistry (IH) and PCR analyses. Results: Hepato-pancreatic ampulla, cystic duct and hepatic duct at hilum contained higher densities of PBGs relative to that found in other sites of the EHBDs. In situ IH demonstrated that PBGs contain cells positive for CK7, CK19, NCAM, CD133/1, insulin, EpCAM, SOX9, SOX 17 and PDX1 and weakly positive for albumin. Progressing deeper in the duct wall, a decreasing of mucin-producing mature cells and an increasing of cells with an endodermal stem cell phenotype could be detected within PBGs. The gallbladder doesn’t contain PBGs, but it does have cells related to those in PBGs. PCR assays of the EHBDs tissue indicated a broad repertoire of endodermal transcription factors and of classic stem/progenitor surface markers other than markers of hepatocytic and pancreatic endocrine lineages. Conclusions: We identified the presence of stem cells with the morphology and the phenotype of endodermal stem cells within PBGs of human EHBDs. The PBGs, as stem cell niches, could play a relevant role in injury repair other than as sites of origin of biliary malignancies (cholangiocarcinoma).
OC12 Candidate stem cell niches in the peribiliary glands (PBGs) of human extra hepatic bile ducts (hEHBDs) G. Carpino 1,2 , V. Cardinale 1 , Y. Wang 3, , M. Gatto 1 , A. Torrice 1 , R. Semeraro 1 , C. Napoli 1 , R. Gentile 1 , G. Mennini 1 , M. Rossi 1 , P.B. Berloco 1 , L.M. Reid 3 , D. Alvaro 1 , E. Gaudio 1 1 “Sapienza” University of Rome, Rome, Italy; 2 University of Rome “Foro Italico”, Rome, Italy; 3 University of North Carolina, Chapel Hill, NC, USA
Background and aim: A stem cells niche has been identified within the human intrahepatic bile duct system at the level of canals of Hering. PBGs are
S315
tubulo-alveolar glands, found deep within the walls of hEHBDs. Until now, the functions of the PBGs have not been known other than mucous production. However, proliferation of cells within PBGs, observed in chronic diseases or associated with malignancies, follows a pattern similar to that with typical stem cell compartment activation. Our aims are to evaluate if PBGs could represent a stem cell niche within the EHBDs and if the sites of higher density of PBGs overlap with known sites of malignancies. Materials and methods: Common hepatic duct, cystic duct, gallbladder and main bile duct were obtained from normal human adult livers and hepatopancreatic ampulla from pancreas. A survey was done (n= 5 human biliary trees) defining the numbers of PBGs by histology, by marker profiles utilizing immunohistochemistry (IH) and PCR analyses. Results: Hepato-pancreatic ampulla, cystic duct and hepatic duct at hilum contained higher densities of PBGs relative to that found in other sites of the EHBDs. In situ IH demonstrated that PBGs contain cells positive for CK7, CK19, NCAM, CD133/1, insulin, EpCAM, SOX9, SOX 17 and PDX1 and weakly positive for albumin. Progressing deeper in the duct wall, a decreasing of mucin-producing mature cells and an increasing of cells with an endodermal stem cell phenotype could be detected within PBGs. The gallbladder doesn’t contain PBGs, but it does have cells related to those in PBGs. PCR assays of the EHBDs tissue indicated a broad repertoire of endodermal transcription factors and of classic stem/progenitor surface markers other than markers of hepatocytic and pancreatic endocrine lineages. Conclusions: We identified the presence of stem cells with the morphology and the phenotype of endodermal stem cells within PBGs of human EHBDs. The PBGs, as stem cell niches, could play a relevant role in injury repair other than as sites of origin of biliary malignancies (cholangiocarcinoma).