Adult Human Liver Research Articles

Immunohistochemical profile of ezrin and radixin in human liver epithelia during fetal development and pediatric cholestatic diseases

Ezrin and radixin are actin-binding proteins that contribute to the integrity of epithelia. Abnormalities of bile secretion occur primarily in cholestatic liver diseases and are associated with changes in cell cytoskeleton. Expression of these proteins during liver development and in cholestatic liver diseases remains poorly investigated. Ezrin and radixin expression was analyzed in fetal, adult and pediatric cholestatic human liver (i.e. biliary atresia, sclerosing cholangitis) by immunohistochemistry. In adult and fetal livers, ezrin was expressed exclusively in the cells of the biliary lineage (i.e. biliary epithelial cells and ductal cells) whereas radixin was located not only in hepatocytes but also in cells of the biliary lineage. In the lobule of mature livers, radixin displayed a zonal distribution with predominant expression in the periportal region. In cholestatic diseases, both proteins were expressed in cells of the ductular reaction. An aberrant expression of ezrin was detected in hepatocytes of cirrhotic nodules with a CK7-positive pattern and in malignant hepatocytes in a course of cholestatic disease toward cancer. Among the components of the liver epithelial cells, ezrin was exclusively expressed in biliary phenotype cells, while radixin was found in biliary and hepatocytic lineages, with a periportal zonal expression. In cholestatic diseases, ezrin was expressed in hepatocytes supporting the appearance of a biliary phenotype.

Isolation of Viable Human Hepatic Progenitors from Adult Livers Is Possible Even After 48 Hours of Cold Ischemia

Liver transplantation, utilized routinely for end-stage liver disease, has been constrained by the paucity of organ donors, and is being complemented by alternative strategies such as liver cell transplantation. One of the most promising forms of liver cell transplantation is hepatic stem cell therapies, as the number of human hepatic stem cells (hHpSCs) and other early hepatic progenitor cells (HPCs) are sufficient to provide treatment for multiple patients from a single liver source. In the present study, human adult livers were exposed to cold ischemia and then processed after <24 or 48 h. Cells positive for epithelial cell adhesion molecule (EpCAM), a marker on early lineage stage HPCs, were immunoselected and counted. Approximately 100,000 EpCAM(+) cells/gram of tissue was obtained from surgical resection of livers subjected to cold ischemia up to 24 h and comparable numbers, albeit somewhat lower, were obtained from those exposed to 48 h of cold ischemia. The yields are similar to those reported from livers with minimal exposure to ischemia. When cultured on plastic dishes and in Kubota's Medium, a serum-free medium designed for early lineage stage HPCs, colonies of rapidly expanding cells formed. They were confirmed to be probable hHpSCs by their ability to survive and expand on plastic and in Kubota's Medium for months, by co-expression of EpCAM and neural cell adhesion molecule, minimal if any albumin expression, with EpCAM found throughout the cells, and no expression of alpha-fetoprotein. The yields of viable EpCAM(+) cells were surprisingly large, and the numbers from a single donor liver are sufficient to treat approximately 50-100 patients given the numbers of EpCAM(+) cells currently used in hepatic stem cell therapies. Thus, cold ischemic livers for up to 48 h are a new source of cells that might be used for liver cell therapies.

EpCam-specific Gold Nanoparticles for Detection, Live-imaging and Rapid Enrichment of Adult Human Liver Progenitor Cells

EpCam-specific Gold Nanoparticles for Detection, Live-imaging and Rapid Enrichment of Adult Human Liver Progenitor Cells

Cultivation and characterisation of human adult liver progenitor cells from patient samples

Aims: Our work centres around human adult liver progenitor cells isolated from primary human hepatocytes received from our clinical cooperation partner at MHH. Hepatocyte samples were isolated by a two-step collagenase perfusion treatment of liver biopsies obtained during liver surgery and cultivated on Collagen-coated culture plates.

A Study of the Normal Morphological Variations of Adult Nigerian Human Cadaveric Liver

Many a times, both anatomist and morbid anatomist have been called upon to use physical features of organs of human body to determine the sex of an individual. This study was conducted to determine the variations in the morphology of an adult human cadaveric liver in Nigeria. Collections of adult human livers 62 (38 male and 24 female) of > 25 years of age was carried out for a period 3 years between March, 2008 and February, 2010 at the gross anatomy laboratories of University of Maiduguri and Abuja. The data were analyzed using percentage and two ways Analysis Of Variance (ANOVA) methods. The studied samples were all found to be darkish-brown, wedged shaped, and firm and friable. The commonest mean weight for male was 1516±0.1g greater than that of female 1333±0.1g. The male mean length was 26.4±0.1cm; width, 15.7±0.2cm; and thickness, 6.0±0.2cm being greater than that of female length, 25.4±0.2 cm; width, 15.0±0.1cm and thickness, 5.5±0.2cm respectively. There was no sex significant variations, P>0.05 in all the studied parameters. This study may be useful in sex determination, studying, research and surgical purposes; and also as diagnostic stools during forensic investigations. However, physiological, pathological, genetic and environmental factors may be responsible for the differences in the weight in both sexes and populations, and require further evaluation.

Ontogeny, distribution and potential roles of 5-hydroxymethylcytosine in human liver function.

BackgroundInterindividual differences in liver functions such as protein synthesis, lipid and carbohydrate metabolism and drug metabolism are influenced by epigenetic factors. The role of the epigenetic machinery in such processes has, however, been barely investigated. 5-hydroxymethylcytosine (5hmC) is a recently re-discovered epigenetic DNA modification that plays an important role in the control of gene expression.ResultsIn this study, we investigate 5hmC occurrence and genomic distribution in 8 fetal and 7 adult human liver samples in relation to ontogeny and function. LC-MS analysis shows that in the adult liver samples 5hmC comprises up to 1% of the total cytosine content, whereas in all fetal livers it is below 0.125%. Immunohistostaining of liver sections with a polyclonal anti-5hmC antibody shows that 5hmC is detected in most of the hepatocytes. Genome-wide mapping of the distribution of 5hmC in human liver samples by next-generation sequencing shows significant differences between fetal and adult livers. In adult livers, 5hmC occupancy is overrepresented in genes involved in active catabolic and metabolic processes, whereas 5hmC elements which are found in genes exclusively in fetal livers and disappear in the adult state, are more specific to pathways for differentiation and development.ConclusionsOur findings suggest that 5-hydroxymethylcytosine plays an important role in the development and function of the human liver and might be an important determinant for development of liver diseases as well as of the interindividual differences in drug metabolism and toxicity.

CITED1 Expression in Liver Development and Hepatoblastoma

Hepatoblastoma, the most common pediatric liver cancer, consists of epithelial mixed embryonal/fetal (EMEF) and pure fetal histologic subtypes, with the latter exhibiting a more favorable prognosis. Few embryonal histology markers that yield insight into the biologic basis for this prognostic discrepancy exist. CBP/P-300 interacting transactivator 1 (CITED1), a transcriptional co-activator, is expressed in the self-renewing nephron progenitor population of the developing kidney and broadly in its malignant analog, Wilms tumor (WT). In this current study, CITED1 expression is detected in mouse embryonic liver initially on post-coitum day 10.5 (e10.5), begins to taper by e14.5, and is undetectable in e18.5 and adult livers. CITED1 expression is detected in regenerating murine hepatocytes following liver injury by partial hepatectomy and 3,5-diethoxycarbonyl-1,4-dihydrocollidine. Importantly, while CITED1 is undetectable in normal human adult livers, 36 of 41 (87.8%) hepatoblastoma specimens express CITED1, where it is enriched in EMEF specimens compared to specimens of pure fetal histology. CITED1 overexpression in Hep293TT human hepatoblastoma cells induces cellular proliferation and upregulates the Wnt inhibitors Kringle containing transmembrane protein 1 (KREMEN1) and CXXC finger protein 4 (CXXC4). CITED1 mRNA expression correlates with expression of CXXC4 and KREMEN1 in clinical hepatoblastoma specimens. These data show that CITED1 is expressed during a defined time course of liver development and is no longer expressed in the adult liver but is upregulated in regenerating hepatocytes following liver injury. Moreover, as in WT, this embryonic marker is reexpressed in hepatoblastoma and correlates with embryonal histology. These findings identify CITED1 as a novel marker of hepatic progenitor cells that is re-expressed following liver injury and in embryonic liver tumors.

Ectopic Overexpression of COTE1 Promotes Cellular Invasion of Hepatocellular Carcinoma

Family with sequence similarity 189, member B (FAM189B), alias COTE1, a putative oncogene selected by microarray, for the first time was here found to be significantly up-regulated in hepatocellular carcinoma (HCC) specimens and HCC cell lines. mRNA expression of COTE1 in HCC samples and cell lines was detected by reverse transcription-polymerase chain reaction (RT-PCR) and real-time PCR, while protein expression of COTE1 in HCC tissues was assessed by immunohistochemistry. In addition, invasion of HCC cells was observed after overexpressing or silencing COTE1. In the total of 48 paired HCC specimens, compared with the adjacent non-cancer tissues, the expression of COTE1 was up-regulated in 31 (p<0.01). In HCC cell lines, COTE1 expression was significantly higher than in normal human adult liver (p<0.01). Overexpression of COTE1 enhanced HCC-derived LM6 and MHCC-L cellular invasion in vitro. In contrast, COTE1 knockdown via RNAi markedly suppressed these phenotypes, as documented in LM3 and MHCC-H HCC cells. Mechanistic analyses indicated that COTE1 could physically associate with WW domain oxidoreductase (WWOX), a tumor suppressor. COTE1 may be closely correlated with invasion of hepatocellular carcinoma (HCC) cells and thus may serve as an effective target for gene therapy.

Perivascular Mesenchymal Progenitors in Human Fetal and Adult Liver

The presence of mesenchymal stem cells (MSCs) has been described in various organs. Pericytes possess a multilineage differentiation potential and have been suggested to be one of the developmental sources for MSCs. In human liver, pericytes have not been defined. Here, we describe the identification, purification, and characterization of pericytes in human adult and fetal liver. Flow cytometry sorting revealed that human adult and fetal liver contains 0.56%±0.81% and 0.45%±0.39% of CD146(+)CD45(-)CD56(-)CD34(-) pericytes, respectively. Of these, 41% (adult) and 30% (fetal) were alkaline phosphatase-positive (ALP(+)). In situ, pericytes were localized around periportal blood vessels and were positive for NG2 and vimentin. Purified pericytes could be cultured extensively and had low population doubling times. Immunofluorescence of cultures demonstrated that cells were positive for pericyte and mesenchymal cell markers CD146, NG2, CD90, CD140b, and vimentin, and negative for endothelial, hematopoietic, stellate, muscle, or liver epithelial cell markers von Willebrand factor, CD31, CD34, CD45, CD144, CD326, CK19, albumin, α-fetoprotein, CYP3A7, glial fibrillary acid protein, MYF5, and Pax7 by gene expression; myogenin and alpha-smooth muscle actin expression were variable. Fluorescence-activated cell sorting analysis of cultures confirmed surface expression of CD146, CD73, CD90, CD10, CD13, CD44, CD105, and ALP and absence of human leukocyte antigen-DR. In vitro differentiation assays demonstrated that cells possessed robust osteogenic and myogenic, but low adipogenic and low chondrogenic differentiation potentials. In functional in vitro assays, cells had typical mesenchymal strong migratory and invasive activity. In conclusion, human adult and fetal livers harbor pericytes that are similar to those found in other organs and are distinct from hepatic stellate cells.

Hematopoietic chimerism in liver transplantation patients and hematopoietic stem/progenitor cells in adult human liver

Liver transplantation (LT) is a cure for many liver diseases. Blood chimerism of donor origin can develop after LT, which raises the possibility of the existence of hematopoietic stem/progenitor cells (HSPCs) in the liver. We characterized the blood chimerism in a large cohort of 249 LT patients and analyzed putative HSPCs in adult human livers. The overall incidence of chimerism was 6.43%, of which 11.11% was among short-term (1 day to 6 months) and 3.77% was among long-term (6 months to 8 years) LT patients. Hematopoietic Lin(-) CD34(+) CD38(-) CD90(+) populations have been demonstrated to generate long-term lymphomyeloid grafts in transplantations. In human adult livers, we detected Lin(-) CD34(+) CD38(-) CD90(+) populations accounting for 0.03% ± 0.017% of the total single liver cells and for 0.05% ± 0.012% of CD45(+) liver cells. Both Lin(-) CD34(+) and Lin(-) CD45(+) liver cells, from extensively perfused human liver grafts, were capable of forming hematopoietic myeloid-lineage and erythroid-lineage methylcellulose colonies. More importantly, Lin(-) CD45(+) or CD45(+) liver cells could be engrafted into hematopoietic cells in an immunodeficient mouse model. These results are the first evidence of the presence of putative HSPC populations in the adult human liver, where the liver is a good ectopic niche. The discovery of the existence of HSPCs in the adult liver have implications for the understanding of extramarrow hematopoiesis, liver regeneration, mechanisms of tolerance in organ transplantation, and de novo cancer recurrence in LT patients. The human adult liver contains a small population of HSPCs. In LT patients, there are two types of chimerisms: transient chimerism, resulting from mature leucocytes, and long-term chimerism, derived from putative HSPCs in the liver graft.

Human Liver Stem Cell-Derived Microvesicles Inhibit Hepatoma Growth in SCID Mice by Delivering Antitumor MicroRNAs

Microvesicles (MVs) play a pivotal role in cell-to-cell communication. Recent studies demonstrated that MVs may transfer genetic information between cells. Here, we show that MVs derived from human adult liver stem cells (HLSC) may reprogram in vitro HepG2 hepatoma and primary hepatocellular carcinoma cells by inhibiting their growth and survival. In vivo intratumor administration of MVs induced regression of ectopic tumors developed in SCID mice. We suggest that the mechanism of action is related to the delivery of microRNAs (miRNAs) from HLSC-derived MVs (MV-HLSC) to tumor cells on the basis of the following evidence: (a) the rapid, CD29-mediated internalization of MV-HLSC in HepG2 and the inhibition of tumor cell growth after MV uptake; (b) the transfer by MV-HLSC of miRNAs with potential antitumor activity that was downregulated in HepG2 cells with respect to normal hepatocytes; (c) the abrogation of the MV-HLSC antitumor effect after MV pretreatment with RNase or generation of MVs depleted of miRNAs; (d) the relevance of selected miRNAs was proven by transfecting HepG2 with miRNA mimics. The antitumor effect of MV-HLSC was also observed in tumors other than liver such as lymphoblastoma and glioblastoma. These results suggest that the delivery of selected miRNAs by MVs derived from stem cells may inhibit tumor growth and stimulate apoptosis. Stem Cells2012;30:1985–1998

Efficient replication of primary or culture hepatitis C virus isolates in human liver slices: A relevant ex vivo model of liver infection

The development of human cultured hepatitis C virus (HCV) replication-permissive hepatocarcinoma cell lines has provided important new virological tools to study the mechanisms of HCV infection; however, this experimental model remains distantly related to physiological and pathological conditions. Here, we report the development of a new ex vivo model using human adult liver slices culture, demonstrating, for the first time, the ability of primary isolates to undergo de novo viral replication with the production of high-titer infectious virus as well as Japanese fulminant hepatitis type 1, H77/C3, and Con1/C3. This experimental model was employed to demonstrate HCV neutralization or HCV inhibition, in a dose-dependent manner, either by cluster of differentiation 81 or envelope protein 2-specific antibodies or convalescent serum from a recovered HCV patient or by antiviral drugs. This new ex vivo model represents a powerful tool for studying the viral life cycle and dynamics of virus spread in native tissue and also allows one to evaluate the efficacy of new antiviral drugs.

A novel peptide with a potential to enhance sorafenib’s therapeutic effects in hepatocellular carcinoma.

e13505 Background: Hepatocellular carcinoma (HCC) is the third leading cause of cancer related deaths worldwide, with chemotherapy or targeted therapy such as sorafenib achieving limited success. Recently stem cell factor SALL4 has emerged as a novel oncogene associated with leukemogenesis and is also implicated in many solid tumors. We have observed that SALL4 is not expressed in adult human liver tissues, but expressed in 30-40% of liver cancer, and this is associated with poorer prognosis and overall survival. We further tested whether inhibition of SALL4 function could be used for HCC treatment. Methods: A novel peptide blocking SALL4 function was designed and used to treat HCC lines with or without SALL4 expression. This is followed by evaluation for binding affinity, tumor growth inhibitory activity and mechanism of action. Treated cells were then transplanted in vivo into NOD/SCID mice and monitored for tumor growth. Comparison and/or combination of peptide with sorafenib were also carried out. Further modification of the peptide was done to allow for in vivo administration. Results: The peptide can effectively block SALL4 function. When used to treat HCC cell lines, it showed inhibitory effects in SNU398 cells (SALL4 expression), but not SNU387 cells (non-SALL4 expression). Post-xenotransplant, mice which received cells treated with peptide had slower rate of tumor growth (p=0.028) and lower tumor burden at dissection 26 days post transplant (p=0.048). Searching for its mechanism of action, we discovered that the peptide could affect the PTEN/AKT pathway, which was validated by western blot. When the peptide was combined with sorafenib, decreased cell viability was observed (p=0.03), suggestive of at least an additive effect between the peptide and sorafenib. Modification of peptide with TAT-protein showed similar inhibition of growth in vitro and was tested for further in-vivo usage through intraperitoneal injection. Conclusions: Our proof-of-principle studies have showed that a peptide blocking the function of stem cell factor SALL4 can be used as a novel approach for treating HCC. Combined with sorafenib, it may be able to enhance cell death and potentially lead to better outcomes in HCC patients.

The Phenotypic Characteristic of Liver-Derived Stem Cells From Adult Human Deceased Donor Liver

Liver transplantation is the only effective treatment for end-stage liver disease. Because of the limited donor availability, attention has been focused on the possibility to restore liver mass and function through cell transplantation. Stem cells are a promising source for liver repopulation after cell transplantation, but whether or not the adult liver contains hepatic stem cells is highly controversial. Several studies have suggested the presence of stem cells in the adult normal human liver. However, a population with stem cell properties has not yet been isolated. The purpose of this study was to identify and characterize progenitor cells in normal adult human liver. We isolated and expanded human liver stem cells (HLSCs) from a donated liver not suitable for liver transplantation or characterizing them by fluorescence-activated cell sorter, polymerase chain reaction, and immunofluorescence assay. HLSCs expressed the mesenchymal stem cell markers CD29, CD73, CD44, CD90, CD105, and CD166 but not the hematopoietic stem cell markers CD34, CD45, and CD117. HLSCs were also positive for vimentin and nestin, a stem cell marker. The absence of staining for cytokeratin-19, CD117, and CD34 indicated that HLSCs were not oval stem cells. In addition, HLSCs expressed CD26, and in a small percentage of cells, cytokeratin-8 and cytokeratin-18, indicating a partial commitment to hepatic cells. We concluded that HLSCs expressed several mesenchymal but not hematopoietic stem cell markers as well as CD26 and CK18, indicating a partial commitment to hepatic cells.

Abstract 3299: Hematopoietic chimerism in liver transplantation patients and hematopoietic stem/progenitor cells in adult human liver

Abstract Liver transplantation (LT) is a cure for many liver diseases. Blood chimerism of donor origin can develop after LT, which raises the possibility of existence of hematopoietic stem/progenitor cells (HSPCs) in liver. We characterized the blood chimerism in a large cohort of 226 LT patients and analyzed putative HSPCs in adult human livers. The overall incidence of chimerism was 6.19%, of which 10.3% was among short-term (one day to six months) and 3.6% was among long-term (six months to eight years) LT patients. Hematopoietic LinαCD34+CD38αCD90+ population has been demonstrated to generate long-term multipotent grafts in transplantations. In human adult livers, we detected LinαCD34+CD38αCD90+ population accounting for 0.056% ± 0.05% of the total single liver cells and for 0.06% ± 0.05% of CD45+ liver cells. Both LinαCD34+ and LinαCD45+ liver cells from extensive perfused human liver graft were capable of forming hematopoietic myeloid-lineage and erythroid-lineage methylcellulose colonies. More importantly, LinαCD45+ or CD45+ liver cells could be engrafted into hematopoietic cells in an immunodeficient mouse model. These results are the first evidence of presence of the putative HSPC population in adult human liver, where liver is a good ectopic niche. The discovery of existence of HSPCs in adult liver will have new implications for understanding of extra-marrow hematopoiesis, liver regeneration, mechanisms of tolerance in organ transplantation and de novo cancer recurrence in LT patients. Conclusion: Human adult liver contains small population of HSPCs. In LT patients, there are two types of chimerism: transient chimerism resulting from mature leucocytes and long-term chimerism deriving from putative HSPCs in the liver graft. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3299. doi:1538-7445.AM2012-3299

Role of Lefty in the anti tumor activity of human adult liver stem cells

Recent studies demonstrated that factors derived from embryonic stem cells inhibit the tumorigenicity of a variety of cancer cell lines. Embryonic stem cell-secreted Lefty, an inhibitor of Nodal-signalling pathway, was implicated in reprogramming cancer cells. Whether adult stem cells exhibited similar properties has not been explored. The aim of the present study was to investigate whether the conditioned medium (CM) derived from adult stem cells influence in vitro and in vivo tumor growth by a Nodal-dependent pathway. In particular we compared the anti-tumor effect of CM from human liver stem cells (HLSC) with that of bone marrow-derived mesenchymal stem cells (MSC). We found that HLSC-CM inhibited the in vitro growth and promoted apoptosis in HepG2 cells that expressed a deregulated Nodal pathway. The effect of HLSC-CM was related to the presence of Lefty A in the CM of HLSC. Silencing Lefty A in HLSC or Lefty A blockade with a blocking peptide abrogated the anti-proliferative and pro-apoptotic effect of HLSC-CM. Moreover, the administration of human recombinant Lefty A protein mimicked the effect of HLSC-CM indicating that Nodal pathway is critical for the growth of HepG2. At variance of HLSC, bone marrow-derived MSC did not express and release Lefty A and the MSC-CM did not exhibited an anti-tumor activity in vitro, but rather stimulated proliferation of HepG2. In addition, the intra-tumor administration of HLSC-CM was able to inhibit the in vivo growth of HepG2 hepatoma cells implanted subcutaneously in SCID mice. At variance, HLSC-CM derived from Lefty A silenced HLSC was unable to inhibit tumor growth. In conclusion, the results of present study suggest that Lefty A may account for the tumor suppressive activity of HLSC as a result of an inhibition of the Nodal-signalling pathway by a mechanism similar to that described for embryonic stem cells.

Flavin-containing monooxygenase 3 gene polymorphisms in Turkish population

Flavin-containing monooxygenases (FMOs) represent the second most important human monooxygenase system, after cytochrome P450s (CYPs) and catalyze the oxygenation of many chemicals containing nitrogen-, sulphur-, phosphorous-, selenium- and other nucleophilic heteroatoms. FMO3 is the prominent FMO form in adult human liver. For FMO3, both interindividual variability within a single ethnic group and variability between ethnic groups have been reported. In our study, three prevalent functional FMO3 variants (E158K, V257M, and E308G) were genotyped in healthy Turkish people by polymerase chain reaction (PCR)–restriction fragment length polymorphism (RFLP) methods. The frequencies of alleles and haplotypes were compared with those obtained from different populations. It was found that FMO3 158K, 257M and 308G alleles, demonstrate impaired metabolism toward many FMO3 substrates, were observed frequently in Turkish population similar to the other populations. Also, the frequencies of haplotypes were determined based on individual allelic frequencies and it was observed that the most common haplotypes were haplotip EVE and KVE (E158K/V257M/E308G), which together accounted for 80% of all haplotypes. The obtained data from the present study could be useful for further studies assessing sensitivity to therapeutic drugs, environmental toxicants and common disease.

Development of a tissue-equivalent human liver phantom for 90Y-microsphere dosimetry studies and testing of other local ablation therapies.

244 Background: 90Y-microsphere brachytherapy for unresectable hepatic cancers is an increasingly popular therapy. The beta radiation dosimetry involved is not well understood and there is lack of pre and post treatment planning capabilities. Methods: A phantom was developed with tissue equivalent electron density, accurate anthropomorphic size, shape and volume to an adult human liver, with similar properties in response to heat, cold, radiation and diagnostic imaging as human liver tissue. Space-occupying masses were created to accommodate implantation of microspheres to simulate a human treatment. Imaging included MRI, CT and SPECT gamma scans pre and post implantation of 90Y-microspheres. Results: A phantom was produced that was shaped from a mold of an adult human liver. A mass with a different density than the liver was created in the right lobe that had a 3mm – 6mm rim for microsphere implantation. A known quantity of 99mTc was implanted into the left lobe. 90Y-microspheres of known activity were implanted in the periphery of the right lobe tumor. CT contrast was mixed with the microspheres to improve localization on subsequent CT scans. The electron density of the phantom was identical to human liver. Microsphere implantation was limited to the outer 6 mm of the right lobe tumor and 99mTc limited to the left lobe. Spatial resolution in 3D was excellent on all three modalities (MRI, CT and SPECT gamma). Conclusions: A human liver phantom as described will be a useful tool in future studies of beta radiation dosimetry, cross sectional and nuclear imaging and tissue responses. The next generation phantom is being developed with blood vessel-like branching channels to allow fluids to pass into and through the phantom similar in scale and diameter to hepatic vessels and tumors.

Lower Expression of HNF4α and PGC1α Might Impair Rifampicin-mediated CYP3A4 Induction under Conditions Where PXR Is Overexpressed in Human Fetal Liver Cells

Pregnane X receptor (PXR) mRNA was detected in HepG2 cells by RT-PCR, but not in human fetal liver (HFL) cells. CYP3A4 was induced by rifampicin (RIF), mifepristone (RU486), clotrimazole (CTZ), and dexamethasone (DEX) in HepG2 cells, while these PXR ligands with the exception of DEX did not induce CYP3A4 mRNA expression in HFL cells. Ad-PXR infection increased mRNA levels of PXR and CYP3A4 in both cells despite the absence of PXR ligands. Similar results were observed in reporter gene assays. However, in HFL cells, RIF-mediated CYP3A4 induction was insufficient compared with HepG2 cells, despite PXR overexpression. The expression levels of five coactivators (HNF4α, PGC1α, SRC1, CBP, and P300) related to CYP3A4 expression in HepG2, HFL cells, and human adult liver were analyzed by RT-PCR. Expression levels of HNF4α and PGC1α in HFL cells were downregulated to 20% of those in the human adult liver. On the other hand, the expression level of HNF4α in HepG2 cells was higher than that in HFL cells, although PGC1α expression level was almost the same as that in HFL cells. HNF4α mRNA expression level in HepG2 cells was 57% of that in human adult liver, and the level in HFL cells was 30% of that in HepG2 cells. These results suggested that lower expression of HNF4α and PGC1α may impair RIF-mediated CYP3A4 induction under conditions of PXR overexpression in HFL cells.

Anatomy of the retrohepatic segment of the inferior vena cava and the ostia venae hepaticae with its clinical significance

The present study was undertaken to provide morphological data regarding the retrohepatic segment of the inferior vena cava (RHIVC) and ostia venae hepaticae with an emphasis on the clinical significance of the observations made. This was an observational study conducted on 160 apparently healthy, randomly selected, cadaveric adult human livers fixed in 10% formalin. The distribution of the hepatic venous openings was studied by dividing the interior of the RHIVC into 16 quadrants. These openings were classified as large, medium, small and very small openings based on their diameter and were also classified as single/double/triple/quadruple according to the number of veins opening into them. The median length of RHIVC was 7.3 cm (6.2-8.4) and was directed obliquely with respect to the vertical axis of the liver in 92.5% of cases. A total of 1,376 ostia venae hepaticae were observed, and the median number of openings per liver was 7 (5-9). The right hepatic vein had a single opening in 156 (97.5%) and the left and middle hepatic veins had a common opening in 144 (90%) cases. A longitudinal area on the anterior wall of the RHIVC, to the right side of the midline, was relatively avascular with 10.1% of the venous openings, of which 70% were single openings of the right dorsal vein having a small diameter (0.1-0.5 cm). During liver hanging maneuver, rightward direction of the dissecting forceps would avoid injury to the caudate vein and allow access to the safe avascular space in the RHIVC.