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Giuliano Ramadori

Publications and source records attributed to Giuliano Ramadori.

At least 19 recordsLinked to original sources
PubMed2006

x-Irradiation in rat liver: consequent upregulation of hepcidin and downregulation of hemojuvelin and ferroportin-1 gene expression.

PURPOSE: To prospectively analyze hepcidin, hemojuvelin, and ferroportin-1 expression after x-irradiation of rat liver and isolated rat hepatocytes. MATERIALS AND METHODS: The treatment of the rats and this study were approved by the local committee and the public authority on animal welfare. Rat livers in vivo and isolated rat hepatocytes in vitro were irradiated. The total number of rats in this study was 43. RNA extracted from livers (1, 3, 6, 12, 24, and 48 hours after irradiation) and from hepatocytes (1, 3, 6, 12, and 24 hours after irradiation) was analyzed with real-time polymerase chain reaction and Northern blot. Cytokines and prohepcidin in serum of irradiated rats were quantitatively detected with enzyme-linked immunosorbent assay. Sham-irradiated animals served as controls in all experiments. Differences between sham-irradiated and irradiated data groups were tested with analysis of variance and Dunnett post hoc test. RESULTS: In vivo, a significant radiation-induced increase of hepcidin (P=.034), interleukin (IL) 1beta (P=.008), IL-6 (P<.011), and tumor necrosis factor alpha (TNF-alpha) (P=.047) expression could be detected within the first 48 hours after irradiation. Expression of hemojuvelin (P=.008) and ferroportin-1 (P=.002) was significantly decreased. Serum iron levels were decreased because of irradiation (P<.058); prohepcidin serum levels were increased (P=.05). In rat hepatocytes in vitro, hepcidin RNA levels were significantly downregulated after irradiation (P<.001). Incubation of irradiated hepatocytes with IL-1beta, IL-6, or TNF-alpha led to upregulation of hepcidin expression in vitro up to 6 hours after irradiation, with subsequent significant downregulation for incubation with IL-1beta (P<.001). Hemojuvelin expression behaved in a way opposite to that of hepcidin. CONCLUSION: x-Irradiation of the liver induced changes of hepcidin gene expression that are probably induced by acute phase mediators produced within the liver itself.

Animals↗
PubMed2006

Adult-to-adult right lobe living donor liver transplantation: comparison of endoscopic retrograde cholangiography with standard T2-weighted magnetic resonance cholangiography for evaluation of donor biliary anatomy.

AIM: To compare the value of endoscopic retrograde cholangiography (ERC) and standard T2-weighted magnetic resonance cholangiography (MRC) in the evaluation process as adult-to-adult right lobe living donor liver transplantation (LDLTx) demands a successful outcome, and exact knowledge of the biliary tree is implicated to avoid biliary complications, postoperatively. METHODS: After starting the LDLTx program, 18 liver transplant candidates were selected for LDLTx by a stepwise evaluation process. ERC and standard T2-weighted MRC were performed to evaluate the biliary system of the donor liver. The anatomical findings of ERC and MRC mapping were compared using the Ohkubo classification. RESULTS: ERC allowed mapping of the whole biliary system in 15/15 (100%) cases, including 14/15 (93.3%) with biliary variants while routine MRC was only accurate in 2/13 (15.4%) cases. MRC was limited in depicting the biliary system proximal of the hepatic bifurcation. Postoperative biliary complications occurred in 2 donors and 8 recipients. Biliary complications were associated with Ohkubo type C, E or G in 6/8 recipients, and 2/3 recipients with biliary leak received a graft with multiple (>=2) bile ducts. CONCLUSION: Pretransplant ERC is safe and superior over standard MRC for detection of biliary variations that occur with a high frequency. However, precise knowledge of biliary variants did not reduce the incidence of postoperative biliary complications.

Adult↗
PubMed2006

Agrin, a novel basement membrane component in human and rat liver, accumulates in cirrhosis and hepatocellular carcinoma.

Agrin is a multifunctional heparan sulfate proteoglycan originally discovered in the neuromuscular junctions and later observed in numerous other localizations. The presence of agrin in the liver, either healthy or diseased, has formerly not been reported. We detected agrin in minor amounts in the basement membranes of blood vessels and bile ducts in the healthy liver. The proliferation of bile ductules and the formation of new septal blood vessels in liver cirrhosis, as well as neoangiogenesis in the hepatocellular carcinoma (HCC) result in a dramatic increase in the quantity of agrin. Vascular and peribiliary basement membranes were strongly immunopositive for agrin in 29/29 human liver specimens with cirrhosis and HCC. However, sinusoidal walls of regenerative nodules in the cirrhotic liver consistently remained negative. Given the selectivity of agrin for tumor microvessels, agrin immunohistochemistry may prove helpful in recognizing malignant transformation in cirrhotic livers. Similar immunohistochemical observations were made on the liver of rats exposed to a combined cirrhosis/HCC induction treatment. In both human and rats, agrin probably originates from activated myofibroblasts, vascular smooth muscle cells and biliary epithelial cells. Increased agrin expression in human specimens, in the liver of 4/4 treated rats, as well as in isolated rat liver mesenchymal cells was verified by quantitative RT-PCR. Considering that agrin binds various growth factors, and it directly interacts with cell membrane receptors such as alphav-integrins, we hypothesize a stimulatory role for agrin in neoangiogenic processes such as tumor vascularization, and a supportive role in bile ductule proliferation.

Agrin↗
PubMed2006

Expression of AFP and Rev-Erb A/Rev-Erb B and N-CoR in fetal rat liver, liver injury and liver regeneration.

BACKGROUND: Alpha-fetoprotein (AFP) expression can resume in the adult liver under pathophysiological conditions. Orphan nuclear receptors were supposed to regulate AFP gene expression, in vitro. We were interested to study the expression of AFP and orphan nuclear receptors, in vivo. RESULTS: The expression of AFP gene and orphan nuclear receptors in the liver was examined in different rat models: (a) fetal liver (b) liver regeneration [partial hepatectomy (PH) with and without 2-acetyl-aminofluren treatment (2-AAF)], (c) acute liver damage [treatment with CCl4] and (d) acute phase reaction [treatment with turpentine oil]. After PH of 2-AAF treated rats, clusters of AFP positive cells occurred in the periportal region. In the Northern blot analysis, a positive hybridization signal for the full-length AFP-RNA was observed only in liver samples from 2-AAF treated rats after PH. In real-time PCR analysis, the full-length AFP-RNA was highly up regulated in the fetal liver (maximum at day 14: 21,500 fold); after PH of 2-AAF treated rats, the full-length AFP-RNA was also up regulated up to 400 fold (day 7 after PH). The orphan nuclear receptors were down regulated at nearly each time points in all models, also at time point of up regulation of the AFP gene. CONCLUSION: Expression of "fetal" AFP could be demonstrated during liver development and during proliferation of the so-called oval cells. Changes of expression of orphan nuclear receptors, however, did not correlate with AFP expression. Other regulatory pathways were possibly involved in controlling AFP expression, in vivo.

Journal Article↗
PubMed2006

Prospero-related homeobox 1 (Prox1) is a stable hepatocyte marker during liver development, injury and regeneration, and is absent from "oval cells".

The aim of this study was to analyse the changes of Prospero-related homeobox 1 (Prox1) gene expression in rat liver under different experimental conditions of liver injury, regeneration and acute phase reaction, and to correlate it with that of markers for hepatoblasts, hepatocytes, cholangiocytes and oval cells. Gene expression was studied at RNA level by RT-PCR, and at protein level by immunohistochemistry. At embryonal stage of rat liver development (embryonal days (ED) 14-16) hepatoblasts were found to be Prox1(+)/Cytokeratin (CK) 19(+) and alpha-fetoprotein (AFP)(+), at this stage Prox1(-)/CK19(+)/AFP(-) small cells (early cholangiocytes?) were identified. In fetal liver (ED 18-22) hepatoblasts were Prox1(+)/CK19(-)/AFP(+). CK7(+) cholangiocytes were detected at this stage, and they were Prox1(-)/AFP(-). In the adult liver hepatocytes were Prox1(+)/CK19(-)/CK7(-)/AFP(-), cholangiocytes were CK19(+) and/or CK7(+) and AFP(-)/Prox1(-). In models of liver damage and regeneration Prox1 remained a stable marker of hepatocytes. After 2-acetyl-aminofluorene treatment with partial hepatectomy (AAF/PH) the amount of Prox1 specific transcripts was low in the liver, when CK19 and AFP gene expression was high, and at no time point AFP(+)/CK19(+ )"oval cells" were found to be Prox1(+). However, a few Prox1(+)/CK19(+) and a few Prox1(+)/CK7(+ )cells were identified in the liver of AAF/PH-animals, which may represent precursors of hepatocytes, or a precancerous state.

2-Acetylaminofluorene↗
PubMed2006

Cytokine-induced neutrophil chemoattractant-1 is released by the noninjured liver in a rat acute-phase model.

The source of serum cytokine-induced neutrophil chemoattractant (CINC-1) and consequences of its presence in the tissue of synthesis have not been clearly elucidated under acute-phase situation. To pursue this question, turpentine oil (TO) was intramuscularly injected into rats, and RNA and local protein levels of acute-phase cytokines and of CINC-1 were studied in the TO injected gluteal muscle, as well as in noninjured muscle, in the liver, kidney, lung and spleen. The serum levels of acute-phase mediators and of CINC-1 were measured together with total leukocyte subpopulations. Recruitment of inflammatory cells in muscle and in the other organs was investigated by quantitative immunohistochemical methods. The effect of acute-phase mediators, including interferon gamma (IFN-gamma) on the synthesis of CINC-1 in cultured hepatocytes was also investigated at the RNA and protein level. We found that the sera of the TO-treated rats contained elevated levels of IL-6, IL-1beta and CINC-1. Increased serum levels of IFN-gamma were also observed not only in the injured muscle but also and to a higher extent in the liver. However, while neutrophils and mononuclear phagocytes were found in the injured muscle, no inflammatory cells were detected at the non-'inflamed' site, namely, the liver or in the other organs. In vitro, treatment of cultured hepatocytes with IL-1beta led to elevated CINC-1 gene expression. This was true to a lesser extent upon IL-6 and tumor necrosis factor (TNF-alpha) exposure. Interestingly, IFN-gamma did not effect CINC-1 gene expression. These results indicate that CINC-1 behaves as an acute-phase protein and its expression is inducible in hepatocytes. However, CINC-1-production in the liver does not lead to recruitment of inflammatory cells into the organ.

Acute-Phase Reaction↗
PubMed2006

Crosstalk between PDGF and IGF-I receptors in rat liver myofibroblasts: implication for liver fibrogenesis.

Insulin-like growth factor I (IGF-I) and platelet-derived growth factor (PDGF) have been identified as significant mitogens for liver myofibroblasts (LMFs), one of the cell populations playing a role in liver fibrogenesis. In the present work, we aimed to elucidate a possible interaction between PDGF receptor (PDGFR) and IGF-I receptor (IGF-IR) signaling in LMFs. Among different rat liver cells, PDGFR alpha- and beta-subunits were mainly expressed in hepatic stellate cells and LMFs, and were upregulated during their in vitro cultivation. In LMFs, PDGF-BB (10 ng/ml) stimulated DNA synthesis approximately two-fold and this effect was similar to that of IGF-I. IGF-I and PDGF-BB differentially affected IGF-IR and PDGFR signaling. High concentrations of IGF-I decreased levels of IGF-IR and IRS-1 and inhibited the expression and activation of PDGFRalpha. PDGF-BB prevented IGF-I-induced downregulation of the IGF-IR, but did not affect expression of its cognate receptor subunits. Transphosphorylation of PDGFR and IGF-IR was not observed. PDGF effectively activated terminal MAP kinases, PI3 kinase and Akt kinase, whereas IGF-I demonstrated weaker effects. PLCgamma(1) was phosphorylated only in response to PDGF, but not to IGF-I. In rat LMFs, blockade of the IGF-IR via inhibition of the IGF-IR kinase completely abrogated IGF- and PDGF-induced mitogenesis and the ability of PDGF to phosphorylate PLCgamma(1). In conclusion, the presented data demonstrate that the PDGFR signaling requires a functional IGF-IR and that PDGF-BB stabilizes the IGF-IR function through preventing the IGF-I-induced downregulation of the IGF-IR. These interactions might be relevant in vivo for the fibroproliferative response during liver injury.

Animals↗
PubMed2006

Hepcidin and hemojuvelin gene expression in rat liver damage: in vivo and in vitro studies.

In this work, we used two rat models, partial hepatectomy (PH) and CCl(4) administration, to study the changes in iron pathways in response to hepatic damage. Liver injury induced changes in the hepatic gene expression of hepcidin, hemojuvelin (Hjv), several other proteins of iron metabolism, and several cytokines such as IL-1beta, IL-6, TNF-alpha, and IFN-gamma. Hepcidin gene expression was upregulated between 4 and 8 h with a maximum up to 16 h after surgery. However, Hjv gene expression was downregulated at the same time. An early upregulation of hepcidin (3 h) and downregulation of Hjv gene expression was found after CCl(4) administration. Transferrin receptor 1 and ferritin H gene expression was upregulated, whereas ferroportin 1 gene expression was downregulated. Hepatic IL-6 gene expression was upregulated early after PH and reached maximum 8 h after the PH. In CCl(4)-induced liver injury, IL-6, IL-1beta, TNF-alpha, and IFN-gamma upregulation were found at the maximum 12 h after the administration of the toxin. Treatment of isolated rat hepatocytes with IL-6 and, to a lesser extent, with IL-1beta but not with TNF-alpha or IFN-gamma dose dependently upregulated hepcidin and downregulated Hjv gene expression. In hepatic damage, changes of the hepatic gene expression of the main proteins involved in iron metabolism may be induced by locally synthesized mediators.

Animals↗
PubMed2006

Regulation of rat heme oxygenase-1 expression by interleukin-6 via the Jak/STAT pathway in hepatocytes.

BACKGROUND/AIMS: Heme oxygenase-1 (HO-1) can be induced by various stimuli, one of which is interleukin-6 (IL-6). Therefore, the aim of this study was to elucidate the molecular mechanisms responsible for IL-6-dependent HO-1 induction in the liver. METHODS: The IL-6-dependent HO-1 regulation in rat primary hepatocytes and HepG2 hepatoma cells was studied by Northern and Western blot analyses, HO-1 promoter reporter gene assays and EMSA. RESULTS: The HO-1 expression was transcriptionally induced by IL-6 in a time- and dose-dependent manner. Activation of signal transducers and activators of transcription (STAT) factors by the IL-6 receptor was crucial for HO-1 induction. By contrast, negative regulation of HO-1 expression appeared to be mediated through the SH2-domain-containing tyrosine phosphatase-2 (SHP2)/ suppressors of cytokine signaling-3 (SOCS3) binding site within the gp130 IL-6 receptor subunit. Among the three putative STAT binding elements (SBE) in the HO-1 promoter, only the distal one was functional and when deleted, the remaining Luc induction was completely obliterated by the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002. CONCLUSIONS: The HO-1 SBE3 mediates HO-1 gene induction by IL-6 mainly via activation of the Jak/STAT pathway.

Animals↗
PubMed2006

Interferon regulatory factor-1 promoter polymorphism and the outcome of hepatitis C virus infection.

OBJECTIVE: Interferon-alpha (IFN-alpha), an important mediator for the host's innate antiviral defense system, has been approved for the treatment of persistent viral infections. We investigated whether two functional polymorphisms in genes involved in IFN-alpha signaling and effector functions are associated with the natural outcome of hepatitis C virus (HCV) infection and the responsiveness of chronic hepatitis C patients to IFN-alpha therapy. METHODS: Forty-four individuals who had resolved HCV infection spontaneously and 147 patients who developed chronic hepatitis C were analyzed for functional single nucleotide polymorphisms in the promoter regions of the interferon regulatory factor-1 (IRF-1) and myxovirus resistance protein-1 (MxA) genes at positions -300 and -88, respectively. RESULTS: With regard to -300 IRF-1 or -88 MxA genotype distributions or minor allele frequencies, individuals who spontaneously resolved the infection displayed no significant difference compared with those with chronic infections. Among patients with chronic infections, however, the -300AA IRF-1 genotype, associated with a higher IRF-1 transcriptional activity, was absent in patients with chronic HCV genotype 3a infections, with one exception. In contrast to expectations, -300AA IRF-1 individuals with HCV genotype 3a infection were not represented in higher numbers among those with self-limited infections. Regarding IFN-alpha therapy, -300AA IRF-1 chronic hepatitis C genotype 1 patients tend to respond more often than those with the other IRF-1 genotypes. CONCLUSION: Our findings suggest the possibility that the -300AA IRF-1 genotype is associated with outcome in patients with HCV genotype 3 infection. In addition, in HCV genotype-1-infected patients, this genotype appears associated with response to therapy.

Adult↗
PubMed2006

Identification of genes responsive to gamma radiation in rat hepatocytes and rat liver by cDNA array gene expression analysis.

The mechanisms underlying hepatocellular damage after irradiation are obscure. We identified genes induced by radiation in isolated rat hepatocytes in vitro by cDNA array gene expression analysis and then screened in vivo experiments with those same genes using real-time PCR and Western blotting. Hepatocytes were irradiated and cDNA array analyses were performed 6 h after irradiation. The mRNA of differentially expressed genes was quantitatively analyzed by real-time PCR. cDNA array analyses showed an up-regulation of 10 genes in hepatocytes 6 h after irradiation; this was confirmed by real-time PCR. In vivo, rat livers were irradiated selectively. Treated and sham-irradiated controls were killed humanely 1, 3, 6, 12, 24 and 48 h after irradiation. Liver RNA was analyzed by real-time PCR; expression of in vivo altered genes was also analyzed at the protein level by Western blotting. Up-regulation was confirmed for three of the in vitro altered genes (multidrug resistance protein, proteasome component C3, eukaryotic translation initiation factor 2). Histologically, livers from irradiated animals were characterized by steatosis of hepatocytes. Thus we identified genes that may be involved in liver steatosis after irradiation. The methods shown in this work should help to further clarify the consequences of radiation exposure in the liver.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2005

Localization of the sulfate/anion exchanger in the rat liver.

Although the sulfate/anion transporter (sat-1; SLC26A1) was isolated from a rat liver cDNA library by expression cloning, localization of sat-1 within the liver and its contribution to the transport of sulfate and organo sulfates have remained unresolved. In situ hybridization and immunohistochemical studies were undertaken to demonstrate the localization of sat-1 in liver tissue. RT-PCR studies on isolated hepatocytes and liver endothelial and stellate cells in culture were performed to test for the presence of sat-1 in these cells. In sulfate uptake and efflux experiments, the substrate specificity of sat-1 was evaluated. Sat-1 mRNA was found in hepatocytes and endothelial cells. Sat-1 protein was localized in sinusoidal membranes and along the borders of hepatocytes. The canalicular region and bile capillaries were not stained. Sulfate uptake was only slightly affected by sulfamoyl diuretics or organo sulfates. Sulfate efflux from sat-1-expressing oocytes was enhanced in the presence of bicarbonate, indicating sulfate/bicarbonate exchange. Estrone sulfate was not transported by sat-1. Sat-1 may be responsible for the uptake of inorganic sulfate from the blood into hepatocytes to enable sulfation reactions. In hepatocytes and endothelial cells, sat-1 may also supply sulfate for proteoglycan synthesis.

Amino Acid Transport System A↗
PubMed2005

Identification of genes specific to "oval cells" in the rat 2-acetylaminofluorene/partial hepatectomy model.

Under certain conditions liver regeneration can be accomplished by hepatic progenitor cells ("oval cells"). So far, only few factors have been identified to be uniquely regulated by the "oval cell" compartment. Using macroarray analysis in a rat model of oval cell proliferation (treatment with 2-acetylaminofluorene and partial hepatectomy, AAF + PH), we identified 12 differentially expressed genes compared to appropriate control models (AAF treatment and sham operation or AAF treatment alone). Further analysis in models of normal liver regeneration (ordinary PH) and acute phase response (turpentine oil-treated rats) revealed that three out of 12 genes (thymidine kinase 1, Jun-D and ADP-ribosylation factor 4) were not affected by the hepatic acute phase reaction but similarly overexpressed in both "oval cell"-dependant and normal liver regeneration. We characterized Jun-D and ADP-ribosylation factors as novel factors upregulated in oval cells and in non-parenchymal liver cells of normally regenerating livers. However, two out of 12 differentially expressed genes were specifically expressed in oval cells: ras-related protein Rab-3b and Ear-2. On protein level, Rab-3b was increased in total liver homogenates and demonstrated only in clusters of oval cells. We postulate that Ear-2 and Rab-3b may represent novel regulatory factors specifically activated in "oval cells".

2-Acetylaminofluorene↗
PubMed2005

Treatment of genotype 2 and 3 chronic hepatitis C virus-infected patients.

AIM: Before pegylated interferon alpha (IFN) was introduced for the therapy of chronic hepatitis C virus (HCV)-induced hepatitis, conventional thrice weekly IFN therapy was supplemented by ribavirin. Also, at that time, higher and more frequent doses of IFN were expected to be more effective than the standard regimen of 3 MU thrice weekly. As ribavirin significantly increases side effects and negatively influences the quality of life particularly in young patients, we started a prospective non-randomized study with a daily IFN-2a monotherapy as an initial treatment for chronic hepatitis C. METHODS: Forty-six consecutive chronic HCV-infected patients received 3 MU IFN-2a per day as an initial treatment. Patients with genotype 2 or 3 (n = 12) were treated for 24 wk, and patients with genotypes other than 2 or 3 (n = 34) for 48 wk. Treatment outcome was followed up for 48 wk after the end of treatment (EOT). Virological response was defined as the absence of detectable serum HCV-RNA. Patients without virological response at 12 wk after the start of treatment received low-dose ribavirin (10 mg(kg/d)) additionally. RESULTS: During treatment, three genotype 3 patients were excluded from the study due to incompliance. The remaining patients (n = 9) infected with genotype 2 or 3 showed an initial virological response rate of 100%. Six patients (66.7%) were still found to be virus-free at the end of follow-up period. In these patients, initial virological response was evident already after 2 wk of treatment. In contrast, initial virological response occurred first after 4 wk of treatment in the three patients who relapsed (33.3%). In comparison, patients infected with genotypes other than 2 or 3 (n = 34) showed an initial virological response rate of only 23.5% (n = 8), and even in combination with ribavirin a sustained virological response (SVR) rate of only 11.8% (n = 4) could be achieved. CONCLUSION: In chronic HCV-infected patients with genotype 2 or 3, a SVR can be expected after 24 wk of daily dose IFN-2a treatment without ribavirin, if initial virological response develops early. This finding is worth to be confirmed in a prospective randomized study with pegylated IFN.

Adult↗
PubMed2005

Prognostic role of E2F1 and members of the CDKN2A network in gastrointestinal stromal tumors.

PURPOSE: The aim of the current study was to examine the prognostic relevance of the CDKN2A tumor suppressor pathway in gastrointestinal stromal tumors (GIST). EXPERIMENTAL DESIGN: We determined the mRNA expression of p1(INK4A), p14(ARF), CDK4, RB1, MDM2, TP53, and E2F1 by quantitative reverse transcription-PCR in 38 cases of GISTs and correlated the findings with clinicopathologic factors, including mutation analysis of KIT and PDGFRA. RESULTS: The k-means cluster analysis yielded three prognostic subgroups of GISTs with distinct mRNA expression patterns of the CDKN2A pathway. GISTs with low mRNA expression of the CDKN2A transcripts p16(INK4A) and p14(ARF) but high mRNA expression of CDK4, RB1, MDM2, TP53, and E2F1 were associated with aggressive clinical behavior and unfavorable prognosis, whereas GISTs with a low mRNA expression of CDK4, RB1, MDM2, TP53, and E2F1 were not. GISTs with a moderate to high mRNA expression of all examined genes also seemed to be associated with unfavorable prognosis. Regarding mutation analysis, we found significant differences in the KIT/PDGFRA genotype among the three clusters. Univariate analysis revealed high expression of E2F1 to be associated with mitotic count, proliferation rate, KIT mutation, and aggressive clinical behavior. These findings on mRNA level could be confirmed by immunohistochemistry. CONCLUSION: Our findings implicate differential regulation schemes of the CDKN2A tumor suppressor pathway converging to up-regulation of E2F1 as the critical link to increased cell proliferation and adverse prognosis of GISTs.

Adult↗
PubMed2005

Expression of osteoactivin in rat and human liver and isolated rat liver cells.

BACKGROUND/AIMS: The transmembrane glycoprotein osteoactivin is expressed in osteoblasts, dendritic cells and tumor cells. It is suggested to influence osteoblast maturation, cell adhesion and migration. We studied osteoactivin expression within the liver. METHODS: Expression of osteoactivin was analysed by RT-PCR, Northern blotting, in situ hybridisation (ISH) and immunohistochemistry (IHC) comparing normal and acutely injured rat liver [induced by carbon tetrachloride (CCl(4)) administration], liver cell populations, and normal or diseased human liver. RESULTS: By ISH osteoactivin expression was detected in sinusoid-lining cells found by IHC to be positive for the common mononuclear phagocyte marker antibody anti-CD68. While total liver contained only traces, isolated Kupffer cells expressed abundant amounts of osteoactivin mRNA further increasing during culture. In acutely injured rat liver osteoactivin expression was strongly increased reaching maximum of expression 48h after CCl(4). By ISH osteoactivin expression was localised in pericentral inflammatory cells and sinusoid-lining cells again anti-CD68 positive. Dexamethasone and lipopolysaccharide decreased osteoactivin expression in cultured mononuclear phagocytes of normal as well as of acutely injured liver. In human liver osteoactivin was increased in fulminant hepatitis and paracetamol intoxication. CONCLUSIONS: Osteoactivin is expressed at high levels in normal and inflammatory liver macrophages suggesting a significant role in acute liver injury.

Acute Disease↗
PubMed2005

Transcriptome analysis of rat liver regeneration in a model of oval hepatic stem cells.

We have performed serial analysis of gene expression of the regenerating liver. In the rat model of partial hepatectomy and 2-acetamidofluorene treatment liver regeneration recruits hepatic stem cells referred to as oval cells. We analyzed a total of 153,057 tags in livers from normal control (52,343 tags), from sham 2-acetamidofluorene-treated control (50,502 tags), and from the early stage of oval cell proliferation (50,212 tags). Comparative analysis of the three transcriptomes identified 27 up-regulated and 18 down-regulated genes. Real-time PCR analysis confirmed 11 temporally regulated genes that correlate with oval cell development. Interestingly, we found by Western blot protein analysis of regenerating livers that the cell cycle gene Cdc42 was induced concomitant with the proliferation marker cyclin D1 and the oval cell marker alpha-fetoprotein. Our studies provide new insights into the molecular mechanism of liver regeneration through oval cells.

2-Acetylaminofluorene↗