Human Hepatic Tissue Research Articles

SAT-296 - Phosphoproteomic Analysis of Intracellular Signaling in the Human Hepatic Tissue of Patients with Non-Alcoholic Fatty Liver Disease and Fibrosis

SAT-296 - Phosphoproteomic Analysis of Intracellular Signaling in the Human Hepatic Tissue of Patients with Non-Alcoholic Fatty Liver Disease and Fibrosis

Increased hepatocellular protein carbonylation in human end-stage alcoholic cirrhosis

ObjectiveOxidative stress is a significant contributing factor in the pathogenesis of alcoholic liver disease (ALD). In the murine models of chronic alcohol consumption, induction of oxidative stress results in increased peroxidation of polyunsaturated fatty acids to form highly reactive electrophilic α/β unsaturated aldehydes that post-translationally modify proteins altering activity. Data are presented here suggesting that oxidative stress and the resulting carbonylation of hepatic proteins is an ongoing process involved in alcohol-induced cirrhosis. MethodsUsing age-matched pooled hepatic tissue obtained from healthy humans and patients with end stage cirrhotic ALD, overall carbonylation was assessed by immunohistochemistry and LC-MS/MS of streptavidin purified hepatic whole cell extracts treated with biotin hydrazide. Identified carbonylated proteins were further evaluated using bioinformatics analyses. ResultsUsing immunohistochemistry and Western blotting, protein carbonylation was increased in end stage ALD occurring primarily in hepatocytes. Mass spectrometric analysis revealed a total of 1224 carbonylated proteins in normal hepatic and end-stage alcoholic cirrhosis tissue. Of these, 411 were unique to cirrhotic ALD, 261 unique to normal hepatic tissue and 552 common to both groups. Bioinformatic pathway analysis of hepatic carbonylated proteins revealed a propensity of long term EtOH consumption to increase post-translational carbonylation of proteins involved in glutathione homeostatic, glycolytic and cytoskeletal pathways. Western analysis revealed increased expression of GSTA4 and GSTπ in human ALD. Using LC-MS/MS analysis, a nonenaldehyde post-translational modification was identified on Lysine 235 of the cytoskeletal protein vimentin in whole cell extracts prepared from human end stage ALD hepatic tissue. Conclusions: These studies are the first to use LC-MS/MS analysis of carbonylated proteins in human ALD and begin exploring possible mechanistic links with end-stage alcoholic cirrhosis and oxidative stress.

Virosomes of hepatitis B virus envelope L proteins containing doxorubicin: synergistic enhancement of human liver-specific antitumor growth activity by radiotherapy.

Bionanocapsules (BNCs) are hollow nanoparticles consisting of hepatitis B virus (HBV) envelope L proteins and have been shown to deliver drugs and genes specifically to human hepatic tissues by utilizing HBV-derived infection machinery. The complex of BNCs with liposomes (LPs), the BNC–LP complexes (a LP surrounded by BNCs in a rugged spherical form), could also become active targeting nanocarriers by the BNC function. In this study, under acidic conditions and high temperature, BNCs were found to fully fuse with LPs (smooth-surfaced spherical form), deploying L proteins with a membrane topology similar to that of BNCs (ie, virosomes displaying L proteins). Doxorubicin (DOX) was efficiently encapsulated via the remote loading method at 14.2%±1.0% of total lipid weight (mean ± SD, n=3), with a capsule size of 118.2±4.7 nm and a ζ-potential of −51.1±1.0 mV (mean ± SD, n=5). When mammalian cells were exposed to the virosomes, the virosomes showed strong cytotoxicity in human hepatic cells (target cells of BNCs), but not in human colon cancer cells (nontarget cells of BNCs), whereas LPs containing DOX and DOXOVES (structurally stabilized PEGylated LPs containing DOX) did not show strong cytotoxicity in either cell type. Furthermore, the virosomes preferentially delivered DOX to the nuclei of human hepatic cells. Xenograft mice harboring either target or nontarget cell-derived tumors were injected twice intravenously with the virosomes containing DOX at a low dose (2.3 mg/kg as DOX, 5 days interval). The growth of target cell-derived tumors was retarded effectively and specifically. Next, the combination of high dose (10.0 mg/kg as DOX, once) with tumor-specific radiotherapy (3 Gy, once after 2 hours) exhibited the most effective antitumor growth activity in mice harboring target cell-derived tumors. These results demonstrated that the HBV-based virosomes containing DOX could be an effective antitumor nanomedicine specific to human hepatic tissues, especially in combination with radiotherapy.

Correlation between the dielectric properties and biological activities of human ex vivo hepatic tissue

Dielectric properties are vital biophysical features of biological tissues, and biological activity is an index to ascertain the active state of tissues. This study investigated the potential correlation between the dielectric properties and biological activities of human hepatic tissue with prolonged ex vivo time through correlation and regression analyses. The dielectric properties of 26 cases of normal human hepatic tissue at 10 Hz to 100 MHz were measured from 15 min after isolation to 24 h at 37 °C with 90% humidity. Cell morphologies, including nucleus area (NA) and alteration rate of intercellular area (ICAR), were analyzed as indicators of biological activities. Conductivity, complex resistivity, and NA exhibited opposing changes 1 h after isolation. Relative permittivity and ex vivo time were not closely correlated (p > 0.05). The dielectric properties measured at low frequencies (i.e. <1 MHz) were more sensitive than those measured at high frequencies in reflecting the biological activity of ex vivo tissue. Highly significant correlations were found between conductivity, resistivity and the ex vivo time (p < 0.05) as well as conductivity and the cell morphology (p < 0.05). The findings indicated that establishing the correlation between the dielectric properties and biological activities of human hepatic tissue is of great significance for promoting the role of dielectric properties in biological science, particularly in human biology.

Targeted label-free approach for quantification of epoxide hydrolase and glutathione transferases in microsomes

The aim of this study was to investigate the expression and organ distribution of cytochrome P450 (CYP450) enzymes, microsomal epoxide hydrolase (MEH), and microsomal glutathione-S-transferase (MGST 1, 2, 3) in human liver, lung, intestinal, and kidney microsomes by targeted peptide-based quantification using nano liquid chromatography–tandem multiple reaction monitoring (nano LC-MRM). Applying this method, we analyzed 16 human liver microsomes and pooled lung, kidney, and intestine microsomes. Nine of the CYP450s (CYP1A2, 2B6, 2C8, 2C9, 2C19, 2D6, 2E1, 3A4, 3A5) could be quantified in liver. Except for CYP3A4 and 3A5 existing in intestine, other CYP450s had little content (<0.1pmol/mg protein) in extrahepatic tissues. MEH and MGSTs could be quantified both in hepatic and in extrahepatic tissues. The highest concentrations of MEH and MGST 1, 2 were found in liver; conversely MGST 3 was abundant in human kidney and intestine compared to liver. The targeted proteomics assay described here can be broadly and efficiently utilized as a tool for investigating the targeted proteins. The method also provides novel CYP450s, MEH, and MGSTs expression data in human hepatic and extrahepatic tissues that will benefit rational approaches to evaluate metabolism in drug development.

Classification and prediction of HCC tissues by Raman imaging with identification of fatty acids as potential lipid biomarkers.

Patients with hepatocellular carcinoma (HCC) can only be treated curatively at early stages and then have a favorable prognosis of this often fatal disease. For this reason, an early detection and diagnostic confirmation are crucial. Raman imaging spectroscopy is a promising technology for high-resolution visualization of the spatial distribution of molecular composition in tissue sections. The aim of this study was to investigate molecular information of liver tissue by Raman imaging for classification and diagnostic prediction. Unstained cryosections of human hepatic tissues (23 patients) were measured by Raman spectroscope in the regions of HCC (n = 12) and fibrosis (n = 17). The acquired data set was used to generate a random forest classification model with 101 iterations of sevenfold cross-validation. The models obtained during cross-validation were also used to predict regions of tumor margin (n = 8) aside from independent testing. Raman spectra differed between malignant and non-malignant tissue regions. Based on these spectral data, a random forest classification model calculated a prediction accuracy of 86 % (76 % sensitivity and 93 % specificity). The ten most important variables were identified at 2895, 2856, 1439, 1298, 1080, 1063, 1023, 937, 920, and 719 cm(-1). In this study, Raman imaging spectroscopy was applied successfully for liver tissue to differentiate, classify, and predict with high accuracy malignant and non-malignant tissue regions. Furthermore, the most important differences were identified as the Raman signature of fatty acids. The demonstrated results highlight the enormous potential which vibrational spectroscopy techniques have for the future diagnostics and prognosis estimation of HCC.

Correlations between transmembrane 4 L6 family member 5 (TM4SF5), CD151, and CD63 in liver fibrotic phenotypes and hepatic migration and invasive capacities.

Transmembrane 4 L6 family member 5 (TM4SF5) is overexpressed during CCl4-mediated murine liver fibrosis and in human hepatocellular carcinomas. The tetraspanins form tetraspanin-enriched microdomains (TEMs) consisting of large membrane protein complexes on the cell surface. Thus, TM4SF5 may be involved in the signal coordination that controls liver malignancy. We investigated the relationship between TM4SF5-positive TEMs with liver fibrosis and tumorigenesis, using normal Chang hepatocytes that lack TM4SF5 expression and chronically TGFβ1-treated Chang cells that express TM4SF5. TM4SF5 expression is positively correlated with tumorigenic CD151 expression, but is negatively correlated with tumor-suppressive CD63 expression in mouse fibrotic and human hepatic carcinoma tissues, indicating cooperative roles of the tetraspanins in liver malignancies. Although CD151 did not control the expression of TM4SF5, TM4SF5 appeared to control the expression levels of CD151 and CD63. TM4SF5 interacted with CD151, and caused the internalization of CD63 from the cell surface into late lysosomal membranes, presumably leading to terminating the tumor-suppressive functions of CD63. TM4SF5 could overcome the tumorigenic effects of CD151, especially cell migration and extracellular matrix (ECM)-degradation. Taken together, TM4SF5 appears to play a role in liver malignancy by controlling the levels of tetraspanins on the cell surface, and could provide a promising therapeutic target for the treatment of liver malignancies.

β-catenin is overexpressed in hepatic fibrosis and blockage of Wnt/β-catenin signaling inhibits hepatic stellate cell activation

β-catenin, a core component of Wnt/β-catenin signaling, has been shown to be an important regulator of cellular proliferation and differentiation. Abnormal activation of Wnt/β-catenin signaling promotes tissue fibrogenesis. In the present study, the role of β-catenin during liver fibrogenesis was analyzed and the functional effects of β-catenin gene silencing in hepatic stellate cells (HSCs) using small interfering (si)RNA were investigated. The expression of β-catenin in human hepatic fibrosis tissues of different grades and normal human hepatic tissues was examined using immunohistochemistry. To inhibit the Wnt/β-catenin signaling pathway, siRNA for β-catenin was developed and transiently transfected into HSC-T6 cells using Lipofectamine 2000. β-catenin expression was evaluated by quantitative polymerase chain reaction (qPCR) and western blot analysis. The expression of collagen types I and III was evaluated by qPCR and immunofluorescent staining. Cellular proliferation and the cell cycle were analyzed using a methyl thiazolyl tetrazolium assay. Apoptosis was assessed by Annexin V staining. A higher expression level of β-catenin was identified in the patients with high-grade hepatic fibrosis in comparison with that of the normal controls. Additionally, β-catenin siRNA molecules were successfully transfected into HSCs and induced inhibition of β-catenin expression in a time-dependent manner. β-catenin siRNA treatment also inhibited synthesis of collagen types I and I in transfected HSCs. Furthermore, compared with those of the control group, siRNA-mediated knockdown of β-catenin in HSC-T6 cells inhibited cell proliferation and resulted in cell apoptosis. This study suggests a significant functional role for β-catenin in the development of liver fibrosis and demonstrates that downregulation of the Wnt/β-catenin signaling pathway inhibits HSC activation. Thus, this study provides a novel strategy for the treatment of hepatic fibrosis.

Lymphotoxin-β receptor signalling links steatohepatitis, hyper-lipidemia and atherosclerosis

Lymphotoxin-β receptor signalling links steatohepatitis, hyper-lipidemia and atherosclerosis

Engineering of human hepatic tissue with functional vascular networks

Although absolute organ shortage highlights the needs of alternative organ sources for regenerative medicine, the generation of a three-dimensional (3D) and complex vital organ, such as well-vascularized liver, remains a challenge. To this end, tissue engineering holds great promise; however, this approach is significantly limited by the failure of early vascularization in vivo after implantation. Here, we established a stable 3D in vitro pre-vascularization platform to generate human hepatic tissue after implantation in vivo. Human fetal liver cells (hFLCs) were mixed with human umbilical vein endothelial cells (HUVECs) and mesenchymal stem cells (hMSCs) and were implanted into a collagen/fibronectin matrix composite that was used as a 3-D carrier. After a couple of days, the fluorescent HUVECs developed premature vascular networks in vitro, which were stabilized by hMSCs. The establishment of functional vessels inside the pre-vascularized constructs was proven using dextran infusion studies after implantation under a transparency cranial window. Furthermore, dynamic morphological changes during embryonic liver cell maturation were intravitaly quantified with high-resolution confocal microscope analysis. The engineered human hepatic tissue demonstrated multiple liver-specific features, both structural and functional. Our new techniques discussed here can be implemented in future clinical uses and industrial uses, such as drug testing.

Elimination of non-specific staining in immunohistochemistry of human liver tissues by modulation of antibody–antigen binding microenvironment

Immunohistochemistry (IHC) is a method of routine use in histopathology for the diagnosis and differentiated diagnosis of liver diseases. IHC staining in human hepatic tissue is often obstructed by the presence of non-specific antibody interactions, the cause of high background staining. Cognizant of previous encounters with high levels of background in human hepatic tissue when using polyclonal antibodies, the potential causes were systemattically investigated by testing the impact of different antibody variants and assay conditions. Firstly, IHC was performed on hepatic tissue with immunized and non-immunized polyclonal antibodies and it was demonstrated that immunized antibodies pervaded the samples with non-specific staining, while non-immunized antibodies produced insignificant background. Following, the primary antibody was co-incubated with different concentrations of protein blocks, acid/base solutions, crystalline ionic compounds, and combinations of these individual components in order to assess their potency in removing background staining. Optimization of these assay conditions revealed that background could be significantly reduced by the addition of sodium chloride to primary antibody solution and/or protein block to sodium azide-stabilized Tris-HCl buffer, while little beneficial effect was observed from co-incubating the primary antibody with non-serum protein block/goat serum, hydrochloric acid/sodium hydroxide, or a higher concentration of peroxidase block. Together, the results suggest that hepatic background in IHC is mainly attributed to strong ionic interactions between the light chains of polyclonal antibodies and polar molecules specifically prevalent in hepatic tissue, which can be reduced by increasing the ionic strength of the antibody–antigen reaction microenvironment. Thus, the findings can enhance the specificity of hepatic tissue immunoassays and improve IHC studies in human liver tissues using polyclonal antibodies.

Bioactivation of nevirapine to a reactive quinone methide: implications for liver injury.

Nevirapine (NVP) treatment is associated with a significant incidence of liver injury. We developed an anti-NVP antiserum to determine the presence and pattern of covalent binding of NVP to mouse, rat, and human hepatic tissues. Covalent binding to hepatic microsomes from male C57BL/6 mice and male Brown Norway rats was detected on Western blots; the major protein had a mass of ∼55 kDa. Incubation of NVP with rat CYP3A1 and 2C11 or human CYP3A4 also led to covalent binding. Treatment of female Brown Norway rats or C57BL/6 mice with NVP led to extensive covalent binding to a wide range of proteins. Co-treatment with 1-aminobenzotriazole dramatically changed the pattern of binding. The covalent binding of 12-hydroxy-NVP, the pathway that leads to a skin rash, was much less than that of NVP, both in vitro and in vivo. An analogue of NVP in which the methyl hydrogens were replaced by deuterium also produced less covalent binding than NVP. These data provide strong evidence that covalent binding of NVP in the liver is due to a quinone methide formed by oxidation of the methyl group. Attempts were made to develop an animal model of NVP-induced liver injury in mice. There was a small increase in ALT in some NVP-treated male C57BL/6 mice at 3 weeks that resolved despite continued treatment. Male Cbl-b–/– mice dosed with NVP had an increase in ALT of >200 U/L, which also resolved despite continued treatment. Liver histology in these animals showed focal areas of complete necrosis, while most of the liver appeared normal. This is a different pattern from the histology of NVP-induced liver injury in humans. This is the first study to report hepatic covalent binding of NVP and also liver injury in mice. It is likely that the quinone methide metabolite is responsible for NVP-induced liver injury.

Serotonin modulates hepatic 6-phosphofructo-1-kinase in an insulin synergistic manner

Human and rat hepatic tissue express many serotonin (5-HT) receptor subtypes, such as 5-HT1B, 5-HT2A, 5-HT2B and 5-HT7 receptors, which mediate diverse effects. 5-HT is known to regulate several key aspects of liver biology including hepatic blood flow, innervations and wound healing. 5-HT is also known to enhance net glucose uptake during glucose infusion in fasted dogs, but little is known about the ability of 5-HT to control hepatic glucose metabolism, especially glycolysis. This study addresses the potential of 5-HT to regulate PFK activity and the mechanisms related to the enzyme activity. Based on our results, we are the first to provide evidence that 5-HT up-regulates PFK in mouse hepatic tissue. Activation of the enzyme occurs through the 5-HT2A receptor and phospholipase C (PLC), resulting in PFK intracellular redistribution and favoring PFK association to the cytoskeletal f-actin-enriched fractions. Interestingly, 5-HT and insulin act in a synergistic manner, likely because of the ability of insulin to increase fructose-2,6-bisphosphate because the presence of this PFK allosteric regulator enhances the 5-HT effect on the enzyme activity. Together, these data demonstrate the ability of 5-HT to control hepatic glycolysis and present clues about the mechanisms involved in these processes, which may be important in understanding the action of 5-HT during the hepatic wound healing process.

Comparative analysis of the human hepatic and adipose tissue transcriptomes during LPS-induced inflammation leads to the identification of differential biological pathways and candidate biomarkers

BackgroundInsulin resistance (IR) is accompanied by chronic low grade systemic inflammation, obesity, and deregulation of total body energy homeostasis. We induced inflammation in adipose and liver tissues in vitro in order to mimic inflammation in vivo with the aim to identify tissue-specific processes implicated in IR and to find biomarkers indicative for tissue-specific IR.MethodsHuman adipose and liver tissues were cultured in the absence or presence of LPS and DNA Microarray Technology was applied for their transcriptome analysis. Gene Ontology (GO), gene functional analysis, and prediction of genes encoding for secretome were performed using publicly available bioinformatics tools (DAVID, STRING, SecretomeP). The transcriptome data were validated by proteomics analysis of the inflamed adipose tissue secretome.ResultsLPS treatment significantly affected 667 and 483 genes in adipose and liver tissues respectively. The GO analysis revealed that during inflammation adipose tissue, compared to liver tissue, had more significantly upregulated genes, GO terms, and functional clusters related to inflammation and angiogenesis. The secretome prediction led to identification of 399 and 236 genes in adipose and liver tissue respectively. The secretomes of both tissues shared 66 genes and the remaining genes were the differential candidate biomarkers indicative for inflamed adipose or liver tissue. The transcriptome data of the inflamed adipose tissue secretome showed excellent correlation with the proteomics data.ConclusionsThe higher number of altered proinflammatory genes, GO processes, and genes encoding for secretome during inflammation in adipose tissue compared to liver tissue, suggests that adipose tissue is the major organ contributing to the development of systemic inflammation observed in IR. The identified tissue-specific functional clusters and biomarkers might be used in a strategy for the development of tissue-targeted treatment of insulin resistance in patients.

Tissue engineering of vascularised human liver organoids: study of morphology phenotypic expression and metabolomics of transitional co-cultures of hepatic/endothelial progenitors

IntroductionTissue architecture and hepatic cell morphology reflect the functional differentiation of the liver. Differentiated functions of hepatocytes, depend on complex, hetereotypic cell-cell/cell-matrix interactions mediated by cell adhesion molecules (CAMs) in...

Human Liver Cells Expressing Albumin and Mesenchymal Characteristics Give Rise to Insulin-Producing Cells

Activation of the pancreatic lineage in the liver has been suggested as a potential autologous cell replacement therapy for diabetic patients. Transcription factors-induced liver-to-pancreas reprogramming has been demonstrated in numerous species both in vivo and in vitro. However, human-derived liver cells capable of acquiring the alternate pancreatic repertoire have never been characterized. It is yet unknown whether hepatic-like stem cells or rather adult liver cells give rise to insulin-producing cells. Using an in vitro experimental system, we demonstrate that proliferating adherent human liver cells acquire mesenchymal-like characteristics and a considerable level of cellular plasticity. However, using a lineage-tracing approach, we demonstrate that insulin-producing cells are primarily generated in cells enriched for adult hepatic markers that coexpress both albumin and mesenchymal markers. Taken together, our data suggest that adult human hepatic tissue retains a substantial level of developmental plasticity, which could be exploited in regenerative medicine approaches.

Up-regulation and subcellular localization of hnRNP A2/B1 in the development of hepatocellular carcinoma

BackgroundHepatocellular carcinoma (HCC) is one of the world's leading causes of death among cancer patients. It is important to find a new biomarker that diagnoses HCC and monitors its treatment. In our previous work, we screened a single-chain antibody (scFv) N14, which could specifically recognize human HepG2 HCC cells but not human non-cancerous liver LO2 cells. However, the antigen it recognized in the cells remained unknown.MethodsRecombinant scFv N14 antibody was expressed as an active antibody. Using this antibody with a combination of immunological and proteomic approaches, we identified the antigen of scFv N14 antibody as the heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNP A2/B1). The expression of hnRNP A2/B1 in HCC cells was then investigated by semi-quantitative RT-PCR and immunohistochemistry.ResultsWe found that the up-regulation of hnRNP A2/B1 was measured at both transcriptional and translational levels in rat HCC cells but not in rat hepatic cells. We also found that in various human hepatic tissues, hnRNP A2/B1 was highly expressed in both human hepatitis virus positive liver tissues and human HCC tissues but not in normal liver tissues. Interestingly, we observed that the localization of hnRNP A2/B1 in HCC cells was altered during the development of HCC. In human hepatitis virus infected tissues hnRNP A2/B1 resides exclusively in the nuclei of hepatocytes. However, when the HCC progressed from a well differentiated to a poorly differentiated stage, hnRNP A2/B1 was increasingly localized in the cytoplasm. In contrast, the HCC tissues with hnRNP A2/B1 highly expressed in the nucleus decreased.ConclusionsThis work is the first to show that hnRNP A2/B1 is the antigen specifically recognized by the scFv N14 antibody in HCC cells. The over-expression of hnRNP A2/B1 was confirmed in cultured human and rat HCC cell lines, human virus related hepatitis liver tissues and human HCC tissues. The increased localization of hnRNP A2/B1 in the cytoplasm of HCC cells was revealed during the dedifferentiation of hepatocellular carcinoma. Therefore, we suggest that the increased expression and cytoplasmic localization of hnRNP A2/B1 can be used as a diagnostic biomarker to assess the risk of human liver cancer.

Effect of hepatocyte growth factor gene transfection on biological features of lymphoma cells

To investigate the biological effect of hepatocyte growth factor (HGF) on HGF gene-transfected Raji cells. Total RNA was extracted from human hepatic tissue, HGF gene cDNA was amplified by RT-PCR, and then cloned into vector pVITRO2-mcs to construct recombinant eukaryotic expression vector pVITRO2-mcs-HGF. The recombinant vector was transfected to Raji cells, and the stably transfected cells were selected by homomycin B in serial passages, and confirmed by real-time fluorescent quantitative PCR, ELISA, immunocytohistochemistry. The biological features of transfected Raji cells were evaluated by semisolid culture. RT-PCR results showed that Raji cells were transfected successfully with recombinant eukaryotic expression vector pVITRO2-mcs-HGF. HGF mRNA and protein were expressed successfully in Raji cells. Expression of HGF gene enhanced proliferation, metastasis and invasion of Raji cells. HGF gene has been cloned and recombined to construct recombinant eukaryotic expression vector pVITRO2-mcs-HGF successfully. Transfected HGF may change the biological features of Raji cells.

Electrical impedance characterization of normal and cancerous human hepatic tissue

The four-electrode method was used to measure the ex vivo complex electrical impedance of tissues from 14 hepatic tumors and the surrounding normal liver from six patients. Measurements were done in the frequency range 1–400 kHz. It was found that the conductivity of the tumor tissue was much higher than that of the normal liver tissue in this frequency range (from 0.14 ± 0.06 S m−1 versus 0.03 ± 0.01 S m−1 at 1 kHz to 0.25 ± 0.06 S m−1 versus 0.15 ± 0.03 S m−1 at 400 kHz). The Cole–Cole models were estimated from the experimental data and the four parameters (ρ0, ρ∞, α, fc) were obtained using a least-squares fit algorithm. The Cole–Cole parameters for the cancerous and normal liver are 9 ± 4 Ω m−1, 2.2 ± 0.7 Ω m−1, 0.5 ± 0.2, 140 ± 103 kHz and 50 ± 28 Ω m−1, 3.2 ± 0.6 Ω m−1, 0.64 ± 0.04, 10 ± 7 kHz, respectively. These data can contribute to developing bioelectric applications for tissue diagnostics and in tissue treatment planning with electrical fields such as radiofrequency tissue ablation, electrochemotherapy and gene therapy with reversible electroporation, nanoscale pulsing and irreversible electroporation.

S1288 Pre-Operative Biliary Drainage in Periampullary Malignancy Does Not Increase the Rates of Postoperative Complication

Background&Aims: Maintenance of intracellular pH is crucial to normal cell function, as many cellular processes have a narrow pH optimum. Tumor cells possess high-glycolytic activity and produce acidic metabolites. Moreover, tumor cells often exist in a hypoxic microenvironment with a lower extracellular pH than that of surrounding normal cells. To survive in this harsh environment, tumor cells must exhibit a dynamic cytosolic pH regulatory system. In this study, we made an investigation on expressions of H+-regulated channels/ exchangers in native human hepatic carcinoma. Methods: The mRNA expressions of Na+/ H+ exchanger (NHE), H+-K+ ATPase, and vacuolar H+-ATPase (V-ATPase) subunit c were examined by real time PCR. The protein expressions were analyzed by Western Blot. The protein expression and intracellular distribution of V-ATPase subunit c was further analyzed by immunohistochemistry. Results: The expressions of mRNA and protein of H+-K+ ATPase were not detected in native human hepatic carcinoma and normal hepatic tissues. The mRNA and protein expression levels of NHE1 and NHE3 were similar in native human hepatic carcinoma and normal hepatic tissues. However, the mRNA and protein expression levels of V-ATPase subunit c in native human hepatic carcinoma were markedly increased, compared with normal hepatic tissues. Immunohistochemistry analysis further confirmed the enhanced expression of V-ATPase subunit c on the plasma membrane of hepatic carcinoma cells. Conclusion: The results demonstrated that the expression of V-ATPase in human hepatic carcinoma is markedly increased, indicating V-ATPase is possibly involved in the regulation of intracellular pH of hepatic carcinoma cells. V-ATPase may represent a potential target for a novel pharmacotherapy of hepatic carcinoma.