by Ho Wai-chun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references. / Abstract also in Chinese. / Title / Dedication / Abstract --- p.i / Table of Contents --- p.iv / Glossary of abbreviation used in the thesis --- p.vi / List of figures --- p.viii / List of tables --- p.xvii / Acknowledgement --- p.xix / Statement of Originality --- p.xx / Chapter Chapter 1 ...... --- Introduction --- p.14 / Chapter Chapter 2...... --- Basic Principle / Chapter 2.1 --- The liver - a vital organ --- p.2-1 / Chapter 2.2 --- Blood supply to the liver --- p.2-7 / Chapter 2.3 --- Normal arterial anatomy of the coeliac axis --- p.2-11 / Chapter 2.4 --- Common anomalies of the coeliac axis --- p.2-17 / Chapter 2.5 --- Previous classification of coeliac anomaies --- p.2-24 / Chapter 2.6 --- Knowledge of arterial anomaly in relation to surgery --- p.2-31 / Chapter 2.7 --- Trans-catheter treatment of hepatocellular carcinoma --- p.2-33 / Chapter 2.8 --- Prevalence of hepatocellular carcinoma in H.K Chinese --- p.2-42 / Chapter 2.9 --- Management of hepatocellular carcinoma in Hong Kong --- p.2-43 / Chapter Chapter 3...... --- Definitions --- p.3-1 / Chapter Chapter 4...... --- Objectives of the study --- p.4-1 / Chapter Chapter 5...... --- "Materials, methods and subjects" / Chapter 5.1 --- Materials --- p.5-1 / Chapter 5.2 --- Methods --- p.5-3 / Chapter 5.3 --- Subjects --- p.5-10 / Chapter Chapter 6...... --- Results / Chapter 6.1 --- Coeliac axis --- p.6-5 / Chapter 6.2 --- Common hepatic artery --- p.6-9 / Chapter 6.3 --- Proper hepatic artery --- p.6-11 / Chapter 6.4 --- Right hepatic artery --- p.6-12 / Chapter 6.5 --- Middle hepatic artery --- p.6-20 / Chapter 6.6 --- Left hepatic artery --- p.6-28 / Chapter 6.7 --- Gastroduodenal artery --- p.6-33 / Chapter 6.8 --- Right gastric artery --- p.6-37 / Chapter 6.9 --- Left gastric artery --- p.5-45 / Chapter 6.10 --- Splenic artery --- p.6-49 / Chapter 6.11 --- Summary of results --- p.6-51 / Chapter Chapter 7...... --- Discussion / Chapter 7.1 --- Introduction --- p.74 / Chapter 7.2 --- Selective Internal Radiation --- p.7-3 / Chapter 7.3 --- Coeliac axis --- p.7-10 / Chapter 7.4 --- Common hepatic & proper hepatic artery --- p.7-7 / Chapter 7.5 --- Right hepatic artery --- p.7-14 / Chapter 7.6 --- Middle hepatic artery --- p.7-18 / Chapter 7.7 --- Left hepatic artery --- p.7-25 / Chapter 7.8 --- Gastroduodenal artery --- p.7-30 / Chapter 7.9 --- Right gastric artery --- p.7-35 / Chapter 7.10 --- Left gastric artery --- p.7-43 / Chapter 7.11 --- Splenic artery --- p.7-45 / Chapter 7.12 --- Comparison with the golden classics --- p.7-47 / Chapter 7.13 --- Comparison of subjects with HCC & without HCC --- p.7-50 / Chapter 7.14 --- Comparison of the male group and the female group --- p.7-51 / Chapter Chapter 8...... --- Conclusions / References --- p.B-1 / Bibliography --- p.B-1 / Appendix I Schematic diagram of histological anatomy of the liver --- p.A-l / Appendix II Embryology --- p.A-2 / "Appendix III Percentages of occurrence of the different types of coeliac axis, by Michels' study" --- p.A-3 / "Appendix IV Percentages of occurrence of the different types of the hepatic arterial blood supply, by Michels' study" --- p.A-4 / Appendix V No. of deaths from malignant liver cancer in Hong Kong froml984 to1993 --- p.A-5 / Appendix VI Flow chart for HCC management in PWH of Hong Kong --- p.A-6 / Appendix VII Comparison with Michels' study --- p.A-7 / Appendix VIII Comparison of the group with HCC and the group without HCC --- p.A-8 / Appendix IX Comparison of the male and female group --- p.A-9

Thesis (doctoral)--University of Lund, 1981. / Includes bibliographical references.

Introdução: A atresia biliar (AB) inclui obstrução completas das vias biliares extra-hepáticas e uma colangiopatia intra-hepática progressiva, cirrogênica. A natureza da colangiopatia destes processos permanece obscura. Uma arteriopatia levando a colangiopatia isquêmica explicaria a natureza progressiva da lesão biliar. A imunolocalização do fator de crescimento endotelial vascular A (VEGFA) em ramos arteriais e ductos biliares intra-hepáticos e do porta hepatis dos pacientes com AB sugere isquemia nestas estruturas. A ocorrência de hipóxia hepatobiliar na AB necessita ser esclarecida. Objetivo: Determinar a presença de hipóxia nos fígados de pacientes com AB, analisando a expressão gênica dos fatores induzidos por hipóxia (HIF) -1α e -2α. Métodos: Estudo de amostras de biópsias em cunha coletadas na laparotomia exploradora de pacientes com AB isolada sem IgM+ para citomegalovírus (n= 32) comparando com lactentes com colestase intra-hepática (CIH, n= 09), pareados por idade. Uma amostra foi ultracongelada (análise molecular) e outra, parafinizada (análises histológica e imunoistoquímica). Por PCRq, usando sondas TaqMan®, avaliaram-se as expressões gênicas de: HIF1-α, HIF2-α, proteína quimiotática de monócitos 1 (MCP1) (marcador de fibrose biliar), citoqueratina 19 (CK19) (marcador de colangiócitos). O gene normalizador foi 18S ribossômico. Por morfometria, foram quantificadas as extensões de fibrose e reação ductular. Dados clínico-laboratoriais foram prospectivamente coletados. Resultados: O grupo AB, comparado à CIH, apresentou maior expressão de HIF1-α e HIF2-α. No grupo AB, a expressão do HIF1-α correlacionou-se positivamente com a bilirrubina total (BT) sérica. Dois subgrupos de AB foram detectados quanto à expressão dos HIFs: alta (hiHIF, expressão 3x maior que a mediana da CIH) e baixa (loHIF). Pacientes hiHIF-1α eram mais velhos e com maiores níveis de BT e bilirrubina direta (BD) que loHIF-1α. O subgrupo hiHIF-2α apresentou expressão de CK19 inferior a do loHIF-2α. As demais variáveis foram semelhantes nos subgrupos HIFs. Conclusão: Na AB ocorre hipóxia tecidual hepática. Os dados sugerem a existência de hipóxia tecidual progressiva nos fígados afetados pela AB, associada ao desaparecimento de ductos biliares e à piora do quadro obstrutivo biliar. / Background: Biliary atresia (BA) includes a complete obstruction of the extrahepatic biliary tract and progressive intrahepatic cholangiopathy, and the nature of these processes remains unclear. An arteriopthy, leading to an ischemic cholangiopathy, can be involved. The immunolocalization of vascular endothelial growth factor A (VEGFA) in arterial branches and bile ducts both within the liver and at porta hepatis from patients with BA suggests ischemia in these structures. The occurrence of hypoxia in the hepatobiliary system in BA needs to be elucidated. Aim: To determinate the presence of hypoxia in the livers from patients with BA, by analyzing the gene expression of hypoxia-inducible factor (HIF) -1α and -2α. Methods: Liver biopsy specimens collected at exploratory laparotomy of age-matched patients with isolated, cytomegalovirus IgM-negative BA (n=32) and intrahepatic cholestasis (IHC, n=9) were evaluated. A sample was ultrafrozen (molecular analysis) and the other was paraffin-embedded (for histological and morphometric analyzes). Gene expression of: HIF-1α, HIF-2α, monocyte chemoattractant protein 1 (MCP1) (biliary fibrosis marker) and cytokeratin 19 (CK19) (cholangiocyte marker) were evaluated by PCRq using TaqMan® probes. The normalizing gene was 18S ribosomal. The extents of fibrosis and ductular reaction were assessed by morphometry. Clinical and laboratory data were prospectively collected. Results: There was higher HIF-1α and HIF-2α expression in BA in comparison with IHC. In BA, the HIF-1α expression was positively correlated with total serum bilirubin (TB). Two groups were observable in BA regarding HIFs: higher (hiHIF, considering as cutoff point a value higher than 3x the median of expression in IHC) and lower (loHIF). Patients with hiHIF-1α were older and presented increased levels of TB and direct-reacting serum bilirubin (DB) than loHIF-1α. Patients with hiHIF-2α presented CK19 expression lower than in loHIF-2α. The other variables were similar in subgroups HIFs. Conclusion: In BA there is hypoxia in the liver tissue, which seems to be progressive and associated with the disappearance of bile ducts and worsening biliary obstruction.

Introdução: A atresia biliar (AB) inclui obstrução completas das vias biliares extra-hepáticas e uma colangiopatia intra-hepática progressiva, cirrogênica. A natureza da colangiopatia destes processos permanece obscura. Uma arteriopatia levando a colangiopatia isquêmica explicaria a natureza progressiva da lesão biliar. A imunolocalização do fator de crescimento endotelial vascular A (VEGFA) em ramos arteriais e ductos biliares intra-hepáticos e do porta hepatis dos pacientes com AB sugere isquemia nestas estruturas. A ocorrência de hipóxia hepatobiliar na AB necessita ser esclarecida. Objetivo: Determinar a presença de hipóxia nos fígados de pacientes com AB, analisando a expressão gênica dos fatores induzidos por hipóxia (HIF) -1α e -2α. Métodos: Estudo de amostras de biópsias em cunha coletadas na laparotomia exploradora de pacientes com AB isolada sem IgM+ para citomegalovírus (n= 32) comparando com lactentes com colestase intra-hepática (CIH, n= 09), pareados por idade. Uma amostra foi ultracongelada (análise molecular) e outra, parafinizada (análises histológica e imunoistoquímica). Por PCRq, usando sondas TaqMan®, avaliaram-se as expressões gênicas de: HIF1-α, HIF2-α, proteína quimiotática de monócitos 1 (MCP1) (marcador de fibrose biliar), citoqueratina 19 (CK19) (marcador de colangiócitos). O gene normalizador foi 18S ribossômico. Por morfometria, foram quantificadas as extensões de fibrose e reação ductular. Dados clínico-laboratoriais foram prospectivamente coletados. Resultados: O grupo AB, comparado à CIH, apresentou maior expressão de HIF1-α e HIF2-α. No grupo AB, a expressão do HIF1-α correlacionou-se positivamente com a bilirrubina total (BT) sérica. Dois subgrupos de AB foram detectados quanto à expressão dos HIFs: alta (hiHIF, expressão 3x maior que a mediana da CIH) e baixa (loHIF). Pacientes hiHIF-1α eram mais velhos e com maiores níveis de BT e bilirrubina direta (BD) que loHIF-1α. O subgrupo hiHIF-2α apresentou expressão de CK19 inferior a do loHIF-2α. As demais variáveis foram semelhantes nos subgrupos HIFs. Conclusão: Na AB ocorre hipóxia tecidual hepática. Os dados sugerem a existência de hipóxia tecidual progressiva nos fígados afetados pela AB, associada ao desaparecimento de ductos biliares e à piora do quadro obstrutivo biliar. / Background: Biliary atresia (BA) includes a complete obstruction of the extrahepatic biliary tract and progressive intrahepatic cholangiopathy, and the nature of these processes remains unclear. An arteriopthy, leading to an ischemic cholangiopathy, can be involved. The immunolocalization of vascular endothelial growth factor A (VEGFA) in arterial branches and bile ducts both within the liver and at porta hepatis from patients with BA suggests ischemia in these structures. The occurrence of hypoxia in the hepatobiliary system in BA needs to be elucidated. Aim: To determinate the presence of hypoxia in the livers from patients with BA, by analyzing the gene expression of hypoxia-inducible factor (HIF) -1α and -2α. Methods: Liver biopsy specimens collected at exploratory laparotomy of age-matched patients with isolated, cytomegalovirus IgM-negative BA (n=32) and intrahepatic cholestasis (IHC, n=9) were evaluated. A sample was ultrafrozen (molecular analysis) and the other was paraffin-embedded (for histological and morphometric analyzes). Gene expression of: HIF-1α, HIF-2α, monocyte chemoattractant protein 1 (MCP1) (biliary fibrosis marker) and cytokeratin 19 (CK19) (cholangiocyte marker) were evaluated by PCRq using TaqMan® probes. The normalizing gene was 18S ribosomal. The extents of fibrosis and ductular reaction were assessed by morphometry. Clinical and laboratory data were prospectively collected. Results: There was higher HIF-1α and HIF-2α expression in BA in comparison with IHC. In BA, the HIF-1α expression was positively correlated with total serum bilirubin (TB). Two groups were observable in BA regarding HIFs: higher (hiHIF, considering as cutoff point a value higher than 3x the median of expression in IHC) and lower (loHIF). Patients with hiHIF-1α were older and presented increased levels of TB and direct-reacting serum bilirubin (DB) than loHIF-1α. Patients with hiHIF-2α presented CK19 expression lower than in loHIF-2α. The other variables were similar in subgroups HIFs. Conclusion: In BA there is hypoxia in the liver tissue, which seems to be progressive and associated with the disappearance of bile ducts and worsening biliary obstruction.

Introdução: A atresia biliar (AB) inclui obstrução completas das vias biliares extra-hepáticas e uma colangiopatia intra-hepática progressiva, cirrogênica. A natureza da colangiopatia destes processos permanece obscura. Uma arteriopatia levando a colangiopatia isquêmica explicaria a natureza progressiva da lesão biliar. A imunolocalização do fator de crescimento endotelial vascular A (VEGFA) em ramos arteriais e ductos biliares intra-hepáticos e do porta hepatis dos pacientes com AB sugere isquemia nestas estruturas. A ocorrência de hipóxia hepatobiliar na AB necessita ser esclarecida. Objetivo: Determinar a presença de hipóxia nos fígados de pacientes com AB, analisando a expressão gênica dos fatores induzidos por hipóxia (HIF) -1α e -2α. Métodos: Estudo de amostras de biópsias em cunha coletadas na laparotomia exploradora de pacientes com AB isolada sem IgM+ para citomegalovírus (n= 32) comparando com lactentes com colestase intra-hepática (CIH, n= 09), pareados por idade. Uma amostra foi ultracongelada (análise molecular) e outra, parafinizada (análises histológica e imunoistoquímica). Por PCRq, usando sondas TaqMan®, avaliaram-se as expressões gênicas de: HIF1-α, HIF2-α, proteína quimiotática de monócitos 1 (MCP1) (marcador de fibrose biliar), citoqueratina 19 (CK19) (marcador de colangiócitos). O gene normalizador foi 18S ribossômico. Por morfometria, foram quantificadas as extensões de fibrose e reação ductular. Dados clínico-laboratoriais foram prospectivamente coletados. Resultados: O grupo AB, comparado à CIH, apresentou maior expressão de HIF1-α e HIF2-α. No grupo AB, a expressão do HIF1-α correlacionou-se positivamente com a bilirrubina total (BT) sérica. Dois subgrupos de AB foram detectados quanto à expressão dos HIFs: alta (hiHIF, expressão 3x maior que a mediana da CIH) e baixa (loHIF). Pacientes hiHIF-1α eram mais velhos e com maiores níveis de BT e bilirrubina direta (BD) que loHIF-1α. O subgrupo hiHIF-2α apresentou expressão de CK19 inferior a do loHIF-2α. As demais variáveis foram semelhantes nos subgrupos HIFs. Conclusão: Na AB ocorre hipóxia tecidual hepática. Os dados sugerem a existência de hipóxia tecidual progressiva nos fígados afetados pela AB, associada ao desaparecimento de ductos biliares e à piora do quadro obstrutivo biliar. / Background: Biliary atresia (BA) includes a complete obstruction of the extrahepatic biliary tract and progressive intrahepatic cholangiopathy, and the nature of these processes remains unclear. An arteriopthy, leading to an ischemic cholangiopathy, can be involved. The immunolocalization of vascular endothelial growth factor A (VEGFA) in arterial branches and bile ducts both within the liver and at porta hepatis from patients with BA suggests ischemia in these structures. The occurrence of hypoxia in the hepatobiliary system in BA needs to be elucidated. Aim: To determinate the presence of hypoxia in the livers from patients with BA, by analyzing the gene expression of hypoxia-inducible factor (HIF) -1α and -2α. Methods: Liver biopsy specimens collected at exploratory laparotomy of age-matched patients with isolated, cytomegalovirus IgM-negative BA (n=32) and intrahepatic cholestasis (IHC, n=9) were evaluated. A sample was ultrafrozen (molecular analysis) and the other was paraffin-embedded (for histological and morphometric analyzes). Gene expression of: HIF-1α, HIF-2α, monocyte chemoattractant protein 1 (MCP1) (biliary fibrosis marker) and cytokeratin 19 (CK19) (cholangiocyte marker) were evaluated by PCRq using TaqMan® probes. The normalizing gene was 18S ribosomal. The extents of fibrosis and ductular reaction were assessed by morphometry. Clinical and laboratory data were prospectively collected. Results: There was higher HIF-1α and HIF-2α expression in BA in comparison with IHC. In BA, the HIF-1α expression was positively correlated with total serum bilirubin (TB). Two groups were observable in BA regarding HIFs: higher (hiHIF, considering as cutoff point a value higher than 3x the median of expression in IHC) and lower (loHIF). Patients with hiHIF-1α were older and presented increased levels of TB and direct-reacting serum bilirubin (DB) than loHIF-1α. Patients with hiHIF-2α presented CK19 expression lower than in loHIF-2α. The other variables were similar in subgroups HIFs. Conclusion: In BA there is hypoxia in the liver tissue, which seems to be progressive and associated with the disappearance of bile ducts and worsening biliary obstruction.

The site of confluence of the artery and the portal vein in the liver still appears to be controversial. Anatomical studies suggested a presinusoidal or an intrasinusoidal confluence in the first, second or even final third of the sinusoids. The objective of this investigation was to study the problem with functional biochemical techniques. Rat livers were perfused through the hepatic artery and simultaneously either in the orthograde direction from the portal vein to the hepatic vein or in the retrograde direction from the hepatic vein to the portal vein. Arterial how was linearly dependent on arterial pressure between 70 cm H2O and 120 cm H2O at a constant portal or hepatovenous pressure of 18 cm H2O. An arterial pressure of 100 cm H2O was required for the maintenance of a homogeneous orthograde perfusion of the whole parenchyma and of a physiologic ratio of arterial to portal how of about 1:3. Glucagon was infused either through the artery or the portal vein and hepatic vein, respectively, to a submaximally effective ''calculated'' sinusoidal concentration after mixing of 0.1 nmol/L. During orthograde perfusions, arterial and portal glucagon caused the same increases in glucose output. Yet during retrograde perfusions, hepatovenous glucagon elicited metabolic alterations equal to those in orthograde perfusions, whereas arterial glucagon effected changes strongly reduced to between 10% and 50%. Arterially infused trypan blue was distributed homogeneously in the parenchyma during orthograde perfusions, whereas it reached clearly smaller areas of parenchyma during retrograde perfusions. Finally, arterially applied acridine orange was taken up by all periportal hepatocytes in the proximal half of the acinus during orthograde perfusions but only by a much smaller portion of periportal cells in the proximal third of the acinus during retrograde perfusions. These findings suggest that in rat liver, the hepatic artery and the portal vein mix before and within the first third of the sinusoids, rather than in the middle or even last third.

121 9. Summárý Purpose: This study was designed to evaluate the role of interventional radiology in liver transplantation programme. The aim is to present our experience, technical outcomes and long-term clinical results with chemoembolization of hepatocellular carcinoma in patients before liver transplantation and with percutaneous treatment of vascular and biliary complication after orthotopic liver transplantation. Methods: Twenty five patients (17 men, 8 women, mean age 57.76 years) with HCC were scheduled for TACE prior to liver transplantation from 2008 to 2012. Twenty three procedures were performed, 7 c-TACE in 2008 and 16 DEB TACE in next years. Thirty patients (13 men, 17 women, mean age 46.4 years) with biliary strictures after liver transplantation without endoscopic access possibility were treated with balloon dilatation and biliary duct drainage from 1996 and 2010. Twenty patients (13 men, 7 women, mean age 45.25 years) were treated with PTA/stent due to hepatic artery stenosis after liver transplantation between 1996 and 2011. Stents were placed to the hepatic/celiac artery in 16 PTAs, balloon dilatation alone was performed in 7 stenosis due to tortuosity of the vessel. Results: Liver transplantation was performed to 20 patients after TACE. Only one patient (4.5 %) was excluded from waiting...

Nos transplantes intervivos de fígado em adultos, o enxerto possui apenas uma artéria segmentar, cujo calibre e extensão são geralmente pequenos. Assim, a distância entre essa artéria do enxerto e a artéria hepática do receptor geralmente é grande e os calibres desproporcionais, tornando tecnicamente difícil a reconstrução arterial hepática. Nestes casos, pode-se utilizar um autoenxerto vascular de interposição para facilitar o procedimento, evitando-se assim complicações cirúrgicas. Objetivo: O presente trabalho se propôs a comparar a artéria mesentérica inferior (AMI), artéria esplênica (AE), artéria epigástrica inferior (AEI), ramo descendente da artéria circunflexa femoral lateral (ACFL) e artéria hepática própria (AHP) como opções de autoenxerto de interposição em transplantes de fígado intervivos em adultos. Método: Foram dissecados 16 cadáveres frescos e coletados as referidas artérias de cada um deles. As variáveis estudadas foram diâmetro do orifício proximal, do distal e comprimento. O diâmetro proximal da AHP e os diâmetros distais AE, AMI, AEI e ramo descendente da ACFL foram comparados ao diâmetro distal da AHD. Os diâmetros proximais e distais da AE, AEI e ramo descendente da ACFL foram comparados entre si para avaliar ganho de calibre. Resultados: Todas as artérias, exceto a AMI, apresentaram diferença estatisticamente significante em relação à AHD quanto à diâmetro. Em termos de ganho de calibre, as artérias apresentaram diferença estatisticamente significante. Todas as artérias, exceto a AHP, apresentaram comprimento de 3 cm. Conclusão: A AMI apresentou a melhor compatibilidade de diâmetro com a AHD e comprimento suficiente para uso como autoenxerto. A AHP, AE, AEI e o ramo descendente da ACFL apresentam calibre estatisticamente diferente da AHD. Destas, somente a AHP não apresentou média de comprimento suficiente para uso em transplante de fígado intervivos / In living donor liver transplantation, the graft presents only a segmental artery, which usually has small diameter and short extension. In these cases, an interpositional arterial autograft can be used in order to obtain vascular extension and better diameter compatibility, making the procedure easier and avoiding surgical complications. Aim: We compared the inferior mesenteric artery (IMA), the splenic artery (SA), the inferior epigastric artery (IEA), the descending branch of the lateral circumflex femoral artery (LCFA) and the proper hepatic artery (PHA) as options of interpositional autograft in living donor liver transplantation. Method: Segments of at least 3 cm of all five arteries were harvested from 16 fresh adult cadavers from both genders through standardized dissection. The analyzed measures were proximal and distal diameter and length. The proximal diameter of RHA and the distal diameter of SA, IMA, IEA and the LCFA were compared to the distal diameter of the RHA. The proximal and distal diameters of the SA, IEA and the LCFA were compared to study caliber gain of each artery. Results: All arteries, except the IMA, showed statistical significant difference in relation to the RHA in terms of diameter. Regarding caliber gain, the arteries demonstrated statistical significant difference. All arteries, except PHA, presented length equal to 3 cm. Conclusion: The IMA demonstrated the best compatibility with the RHA in terms of diameter and has shown sufficient length to be employed as interpositional graft. The PHA, the SA, the IEA and the LCFA presented statistically significant different diameters when compared to the RHA. Among these vessels, only the PHA did not show sufficient mean length

INTRODUÇÃO: O transplante hepático é o único tratamento efetivo para uma variedade de doenças hepáticas irreversíveis. No entanto, o número limitado de doadores pediátricos leva ao uso de enxertos hepáticos de doadores adultos, com necessidade de anastomoses vasculares mais complexas. Essas anastomoses tornam-se complicadas pela diferença no calibre dos vasos entre o doador e o receptor, resultando em alterações do fluxo sanguíneo, estenose da anastomose venosa ou arterial e trombose. Os efeitos para regeneração hepática decorrentes da privação do fluxo sanguíneo pela veia porta ou pela artéria hepática não estão completamente elucidados. Experimentalmente, quando um lobo do fígado não recebe o fluxo venoso portal, é observada atrofia deste segmento e hipertrofia do restante do órgão perfundido. Embora existam vários modelos experimentais para estudo da regeneração hepática, poucos são focados em animais em crescimento. Além disso, os efeitos regenerativos de drogas como o tacrolimus e a insulina precisam ser pesquisados, com o objetivo de encontrar um tratamento ideal para a insuficiência hepática ou um método de estimular a regeneração do fígado após ressecções ou transplantes parciais. O objetivo do presente estudo é descrever modelos de regeneração hepática em ratos em crescimento com: 1) ausência de fluxo hepático arterial e 2) redução do fluxo portal. Adicionalmente, o estudo avalia o efeito pró-regenerativo do tacrolimus e da insulina nesses modelos descritos. MÉTODOS: cento e vinte ratos (entre 50 e 100g de peso) foram divididos em 6 grupos, de acordo com o tipo de intervenção cirúrgica: Grupo 1, incisão abdominal sem intervenção hepática; Grupo 2, hepatectomia a 70%; Grupo 3, hepatectomia a 70% + estenose de veia porta; Grupo 4, hepatectomia a 70% + ligadura da artéria hepática; Grupo 5, hepatectomia a 70% + estenose de veia porta + insulina; Grupo 6, hepatectomia a 70% + estenose de veia porta + tacrolimus. Os animais dos grupos 1 ao 4 foram subdivididos em 5 subgrupos de acordo com o momento da morte: 1, 2, 3, 5 e 10 dias após a intervenção cirúrgica. Os animais dos grupos 5 e 6 foram subdividos em 2 subgrupos de acordo com o momento da morte: 2 e 10 dias após a intervenção cirúrgica. Os lobos hepáticos remanescentes foram submetidos à análise histomorfométrica, imuno-histoquímica e molecular. RESULTADOS: Verificou-se que no grupo com hepatectomia a 70% houve recuperação do peso do fígado no terceiro dia com aumento da atividade mitótica, enquanto que no grupo com estenose portal não se observou esse fenômeno (p < 0,001). A insulina e o tacrolimus promoveram aumento do peso do fígado e do índice mitótico. A atividade mitótica foi considerada aumentada nos animais dos grupos hepatectomia, hepatectomia + ligadura da artéria, insulina e tacrolimus; e esse parâmetro estava reduzido no grupo submetido à hepatectomia + estenose portal (p < 0,001). A expressão de interleucina 6 estava presente em todos os animais, sendo significativamente maior nos grupos hepatectomia, hepatectomia + ligadura da artéria e significativamente menor no grupo hepatectomia + estenose portal. Entretanto, a administração de tacrolimus ou insulina recuperou os níveis teciduais de interleucina 6 no grupo com estenose portal. CONCLUSÕES: No presente estudo foi padronizado um modelo simples e facilmente reprodutível para estudar a regeneração hepática em ratos em crescimento com redução do fluxo arterial ou venoso para o fígado. Foi demonstrado que a administração de insulina ou tacrolimus é capaz de reverter os efeitos deletérios da estenose portal na regeneração hepática. A obstrução do fluxo arterial não afetou a capacidade regenerativa hepática / BACKGROUND/PURPOSE: Liver transplantation is an effective treatment for a variety of irreversible liver diseases. However, the limited number of pediatric donor livers leads to the use of adult livers, which usually require more complex vascular anastomoses. These anastomoses are complicated by differences in vessel caliber between donors and recipients, resulting in vascular flow anomalies, stenosis of the venous or arterial anastomosis and thrombosis . The effects of portal vein or hepatic arterial flow privation in hepatic regeneration have not been completely elucidated. Experimentally, when a liver lobe is deprived of portal vein flow, atrophy is observed with hypertrophy of the other perfused parts of the organ, and interleukin-6 (IL-6) is required for normal liver regeneration. Although several experimental models are currently used to study the liver regeneration mechanisms, few studies have focused on the growing animal. In addition, the regenerative effects of drugs (e.g., tacrolimus and insulin) have been experimentally studied, aiming to find an ideal treatment for hepatic failure or a method of stimulating liver regeneration after extensive resection or partial transplants. The aim of the present investigation was to describe the new models of liver regeneration in growing rats with: 1) absence of arterial blood hepatic inflow and 2) reduced portal flow. Additionally, it was studied whether tacrolimus or insulin could have any pro-regenerative effect under such conditions. METHODS/MATERIALS: one hundred and twenty rats (50-100 g body weight) were divided into 6 groups based on the intervention type: Group 1 (sham), abdominal incision without intervention; Group 2, 70% hepatectomy; Group 3, 70% hepatectomy + portal vein stenosis; Group 4, 70% hepatectomy + ligation of the hepatic artery; Group 5, 70% hepatectomy + portal vein stenosis + insulin; and Group 6, 70% hepatectomy + portal vein stenosis + tacrolimus. Animals in groups 1 to 4 were subdivided into 5 groups according to the moment of death: 1, 2, 3, 5 and 10 days after surgical intervention. The animals in groups 5 and 6 were subdivided into 2 other groups according to the moment of death: 2 and 10 days after surgical intervention. The remnant liver lobes were harvested for morphological, histological histomorphometric, immunohistochemical and molecular analyses. RESULTS: it was verified that the hepatectomy group regained liver weight on the third day and had increased mitotic activity, and the portal vein stenosis prevented these phenomena, as well as the increased mitotic index (P < 0.001). In addition, insulin and tacrolimus promoted a significant increase of liver weight. Mitotic activity was considerably increased in the hepatectomy, hepatectomy + arterial ligature, insulin and tacrolimus groups and this parameter was reduced by portal vein stenosis. The expression of the interleukin-6 (IL-6) gene was present in all the animal groups. Tissue levels of IL- 6 were significantly increased by hepatectomy and hepatectomy + hepatic artery ligature; portal vein stenosis prevented this change. However, the administration of tacrolimus or insulin could recuperate the tissue levels of IL-6. CONCLUSION: In the present study a simple and highly reproducible model was standardized to study liver regeneration with portal vein or hepatic artery blood inflow reduction in growing rats. It was demonstrated that insulin or tacrolimus administration may partially reverse the harmful effects of portal vein stenosis. The obstruction of the arterial flow did not affect liver regeneration

INTRODUÇÃO: O transplante hepático é o único tratamento efetivo para uma variedade de doenças hepáticas irreversíveis. No entanto, o número limitado de doadores pediátricos leva ao uso de enxertos hepáticos de doadores adultos, com necessidade de anastomoses vasculares mais complexas. Essas anastomoses tornam-se complicadas pela diferença no calibre dos vasos entre o doador e o receptor, resultando em alterações do fluxo sanguíneo, estenose da anastomose venosa ou arterial e trombose. Os efeitos para regeneração hepática decorrentes da privação do fluxo sanguíneo pela veia porta ou pela artéria hepática não estão completamente elucidados. Experimentalmente, quando um lobo do fígado não recebe o fluxo venoso portal, é observada atrofia deste segmento e hipertrofia do restante do órgão perfundido. Embora existam vários modelos experimentais para estudo da regeneração hepática, poucos são focados em animais em crescimento. Além disso, os efeitos regenerativos de drogas como o tacrolimus e a insulina precisam ser pesquisados, com o objetivo de encontrar um tratamento ideal para a insuficiência hepática ou um método de estimular a regeneração do fígado após ressecções ou transplantes parciais. O objetivo do presente estudo é descrever modelos de regeneração hepática em ratos em crescimento com: 1) ausência de fluxo hepático arterial e 2) redução do fluxo portal. Adicionalmente, o estudo avalia o efeito pró-regenerativo do tacrolimus e da insulina nesses modelos descritos. MÉTODOS: cento e vinte ratos (entre 50 e 100g de peso) foram divididos em 6 grupos, de acordo com o tipo de intervenção cirúrgica: Grupo 1, incisão abdominal sem intervenção hepática; Grupo 2, hepatectomia a 70%; Grupo 3, hepatectomia a 70% + estenose de veia porta; Grupo 4, hepatectomia a 70% + ligadura da artéria hepática; Grupo 5, hepatectomia a 70% + estenose de veia porta + insulina; Grupo 6, hepatectomia a 70% + estenose de veia porta + tacrolimus. Os animais dos grupos 1 ao 4 foram subdivididos em 5 subgrupos de acordo com o momento da morte: 1, 2, 3, 5 e 10 dias após a intervenção cirúrgica. Os animais dos grupos 5 e 6 foram subdividos em 2 subgrupos de acordo com o momento da morte: 2 e 10 dias após a intervenção cirúrgica. Os lobos hepáticos remanescentes foram submetidos à análise histomorfométrica, imuno-histoquímica e molecular. RESULTADOS: Verificou-se que no grupo com hepatectomia a 70% houve recuperação do peso do fígado no terceiro dia com aumento da atividade mitótica, enquanto que no grupo com estenose portal não se observou esse fenômeno (p < 0,001). A insulina e o tacrolimus promoveram aumento do peso do fígado e do índice mitótico. A atividade mitótica foi considerada aumentada nos animais dos grupos hepatectomia, hepatectomia + ligadura da artéria, insulina e tacrolimus; e esse parâmetro estava reduzido no grupo submetido à hepatectomia + estenose portal (p < 0,001). A expressão de interleucina 6 estava presente em todos os animais, sendo significativamente maior nos grupos hepatectomia, hepatectomia + ligadura da artéria e significativamente menor no grupo hepatectomia + estenose portal. Entretanto, a administração de tacrolimus ou insulina recuperou os níveis teciduais de interleucina 6 no grupo com estenose portal. CONCLUSÕES: No presente estudo foi padronizado um modelo simples e facilmente reprodutível para estudar a regeneração hepática em ratos em crescimento com redução do fluxo arterial ou venoso para o fígado. Foi demonstrado que a administração de insulina ou tacrolimus é capaz de reverter os efeitos deletérios da estenose portal na regeneração hepática. A obstrução do fluxo arterial não afetou a capacidade regenerativa hepática / BACKGROUND/PURPOSE: Liver transplantation is an effective treatment for a variety of irreversible liver diseases. However, the limited number of pediatric donor livers leads to the use of adult livers, which usually require more complex vascular anastomoses. These anastomoses are complicated by differences in vessel caliber between donors and recipients, resulting in vascular flow anomalies, stenosis of the venous or arterial anastomosis and thrombosis . The effects of portal vein or hepatic arterial flow privation in hepatic regeneration have not been completely elucidated. Experimentally, when a liver lobe is deprived of portal vein flow, atrophy is observed with hypertrophy of the other perfused parts of the organ, and interleukin-6 (IL-6) is required for normal liver regeneration. Although several experimental models are currently used to study the liver regeneration mechanisms, few studies have focused on the growing animal. In addition, the regenerative effects of drugs (e.g., tacrolimus and insulin) have been experimentally studied, aiming to find an ideal treatment for hepatic failure or a method of stimulating liver regeneration after extensive resection or partial transplants. The aim of the present investigation was to describe the new models of liver regeneration in growing rats with: 1) absence of arterial blood hepatic inflow and 2) reduced portal flow. Additionally, it was studied whether tacrolimus or insulin could have any pro-regenerative effect under such conditions. METHODS/MATERIALS: one hundred and twenty rats (50-100 g body weight) were divided into 6 groups based on the intervention type: Group 1 (sham), abdominal incision without intervention; Group 2, 70% hepatectomy; Group 3, 70% hepatectomy + portal vein stenosis; Group 4, 70% hepatectomy + ligation of the hepatic artery; Group 5, 70% hepatectomy + portal vein stenosis + insulin; and Group 6, 70% hepatectomy + portal vein stenosis + tacrolimus. Animals in groups 1 to 4 were subdivided into 5 groups according to the moment of death: 1, 2, 3, 5 and 10 days after surgical intervention. The animals in groups 5 and 6 were subdivided into 2 other groups according to the moment of death: 2 and 10 days after surgical intervention. The remnant liver lobes were harvested for morphological, histological histomorphometric, immunohistochemical and molecular analyses. RESULTS: it was verified that the hepatectomy group regained liver weight on the third day and had increased mitotic activity, and the portal vein stenosis prevented these phenomena, as well as the increased mitotic index (P < 0.001). In addition, insulin and tacrolimus promoted a significant increase of liver weight. Mitotic activity was considerably increased in the hepatectomy, hepatectomy + arterial ligature, insulin and tacrolimus groups and this parameter was reduced by portal vein stenosis. The expression of the interleukin-6 (IL-6) gene was present in all the animal groups. Tissue levels of IL- 6 were significantly increased by hepatectomy and hepatectomy + hepatic artery ligature; portal vein stenosis prevented this change. However, the administration of tacrolimus or insulin could recuperate the tissue levels of IL-6. CONCLUSION: In the present study a simple and highly reproducible model was standardized to study liver regeneration with portal vein or hepatic artery blood inflow reduction in growing rats. It was demonstrated that insulin or tacrolimus administration may partially reverse the harmful effects of portal vein stenosis. The obstruction of the arterial flow did not affect liver regeneration