Academic literature on the topic 'Dysplastic hepatocytes'

Tumor hemodynamics of carcinogenic hepatocytes nodules, that is, low grade dysplastic nodules, high grade dysplastic nodules, early hepatocellular carcinomas (HCCs), and progressed HCCs, change during multistep dedifferentiation of the nodules. Morphometric analyses of inflow vessels of these nodules indicate that the portal veins of carcinogenic hepatocyte nodules monotonically decrease whereas the arteries bitonically change, first decrease and then increase. Findings on imaging techniques depicting these changes in tumor blood inflows, especially intra-arterial contrast-enhanced computed tomography, closely related not only to the histological differentiation of the nodules but also to the outcomes of the nodules. Histological analyses of connections between the vessels within the tumors and those in the surrounding livers and findings on imaging techniques indicate that drainage vessels of HCC change from hepatic veins to hepatic sinusoids and then to portal veins during multistep hepatocarcinogenesis. Understanding of tumor hemodynamics through radio-pathological correlations will be helpful in drawing up therapeutic strategies for carcinogenic hepatocyte nodules arising in cirrhosis.

Small fish models have been used for decades in carcinogenicity testing. Demonstration of common morphological changes associated with specific mechanisms is a clear avenue by which data can be compared across divergent phyletic levels. Dimethylnitrosamine, used in rats to model human alcoholic cirrhosis and hepatic neoplasia, is also a potent hepatotoxin and carcinogen in fish. We recently reported some striking differences in the mutagenicity of DMN in lambda cII transgenic medaka fish vs. Big Blue® rats, but the pre-neoplastic and neoplastic commonalities between the two models are largely unknown. Here, we focus on these commonalities, with special emphasis on the TGF- β pathway and its corresponding role in DMN-induced hepatic neoplasia. Similar to mammals, hepatocellular necrosis, regeneration, and dysplasia; hepatic stellate cell and “spindle cell” proliferation; hepatocellular and biliary carcinomas; and TGF-β1 expression by dysplastic hepatocytes all occurred in DMN-exposed medaka. Positive TGF- β1 staining increased with increasing DMN exposure in bile preductular epithelial cells, intermediate cells, immature hepatocytes and fewer mature hepatocytes. Muscle specific actin identified hepatic stellate cells in DMN-exposed fish. Additional mechanistic comparisons between animal models at different phyletic levels will continue to facilitate the interspecies extrapolations that are so critical to toxicological risk assessments.

Background/Aim. The vascular supply of dysplastic nodules (DN) is altered compared with surrounding cirrhotic nodules. Dysplastic nodules contain unpaired arteries which are isolated arteries unaccompained by bille ducts. In adition, capillarization or neovascularization is evident on CD34 and CD31 staining. The investigation of angiogenic profile of regenerative, dysplastic and nodules of hepatocellular carcinoma aimed at assessing whether vascular profile is in reliance to the process of dedifferentiation of hepatocytes during the course of cirrhosis. Methods. Thirty four liver nodules from surgical biopsies of 12 patients previously undiagnosed to have cirrhosis, were classified as regenerative, dysplastic and small hepatocellular carcinomas (HCC). The investigation included 8 large regenerative nodules (LRN), 11 low grade dysplastic nodules (LGDN), 12 high grade dysplastic nodules (HGDN) and 3 early HCC. Serial sections of the nodules and surrounding cirrhotic liver tissue were immunostained against CD34. The vascular counting method was performed. The results were analysed using SPSS computer statistical program. Results. The number of capillary unites showed significant differences among nodular types, with the largest number of capillaries in hepatocellular carcinoma as well as strong reliance to dedifferentiation. Conclusion. There is a significant correlation of sinusoidal capillarization to dediferentiation of the liver tissue during the course of cirrhosis. From diagnostic view, capillary counting may be helpfull to distinguish dysplastic from nondysplastic nodules. The appearance of dysplastic nodules in nonselected surgical biopsies is frequent enough to challenge caution during the follow-up of cirrhotic patients.

Lung resistance-related protein (LRP) plays an important role in chemoresistance of tumor cells probably by altering nuclear-cytoplasmic transport processes. We analyzed the association between LRP expression and hepatocarcinogenesis in humans and rats by RT-PCR, immunoblotting, and immunohistochemistry. LRP was found in hepatocytes and bile epithelia of normal human and rat liver showing distinct interindividual variations. In human tissues, the LRP expression levels of dysplastic liver nodules, hepatocellular adenomas, and carcinomas were highly variable, including decreased but also distinctly increased staining intensities. Mean expression levels, however, were comparable to the surrounding tissue. Considerable levels of LRP mRNA and protein were also found in human hepatoma cell lines. To study LRP expression from the beginning of hepatocarcinogenesis onward, rats were subjected to a tumor initiation/promotion protocol leading to preneoplastic hepatocytes present as single cells or multicellular clones, followed by adenoma and carcinoma. All of the (pre)neoplastic rat liver lesions expressed, comparable to the surrounding tissue, considerable amounts of LRP. We conclude that LRP might be one mechanism involved in the intrinsically high but variable chemoresistance of normal and (pre)neoplastic hepatocytes.

ABSTRACT The hepatobiliary-specific contrast medium (gadoxetic acid – Primovist®) is primarily used to improve detection and characterization of focal hepatic lesions, such as in chronic liver disease patients with suspected hepatocellular carcinoma. Since the contrast medium is selectively taken up by functioning hepatocytes in the late hepatobiliary phase, it helps to detect typical hepatocellular carcinoma, which show low signal intensity on this phase. This imaging feature also assists in differentiating regenerative/dysplastic nodules from early hepatocellular carcinomas (with over 90% accuracy), as well as hypervascular hepatocellular carcinomas from arterial pseudo-enhancement foci. Future perspectives include its use in quantification of hepatic function and fibrosis.

Background/Aim. A study of morphological lesions in the liver of heroin addicts enables a precise overview of the type and degree of the liver damages caused by intravenous (iv) heroin abuse, additive effects of viral infections and alcohol consumption, as well as whether the expressiveness of these lesions depends on the duration of the time period of heroin application. The aim of the study was to investigate histopathological, ultrastructural and morphometric features of the liver of heroin addicts in forensic samples of the liver. Methods. The study involved the autopsy conducted on 40 bodies of iv heroin addicts and 10 control autopsies. The investigated group consisted of liver samples of 36 male subjects and 4 female subjects aged 35-40 years and the control group of 8 male and 2 female cadaveric bodies aged 15-35 years. The liver tissue samples were prepared for light microscopy. Sections of the tissue paraffin blocks 5 ? thick were stained using classical Hematoxylin and Eosin method (H&E), as well as PAS Van Gieson, Gomori, and Congo Red techniques. For investigation purposes of ultrastructural changes, liver tissue was fixed in glutaraldehyde and molded with epon. The analysis was performed using the method of transmission electron microscopy. Morphometric investigation of the liver sinusoidal macrophages was performed by using the M42 test system. Results. In the investigated group of iv heroin addicts, the liver autopsy samples showed degenerative vesicular and fat changes, chronic hepatitis, cirrhosis, sedimentation of pathologic protein amyloidosis, dysplastic changes, reduction in the amount of glycogen in hepatocytes, as well as the change in the number of Kupfer and endothelial cells. The established changes correlated with the duration of iv heroin abuse, whereas sinusoidal macrophages were activated in cases with active hepatitis, and no significant change in their number was found in hepatocytes with alcohol-related fatty changes. Conclusion. The study showed that the most present change in the hepatocytes of drug addicts was vesicular degeneration, and it is the only direct consequence of the effect of heroin. Other morphological changes were present due to viral infections and they correlated with the duration of narcotic abuse. The finding of dysplastic changes in this susceptible population of young people is particularly significant. The forensic significance of the established changes in the liver tissue is in the possibility of their practical application for determination of the immediate cause of death of iv heroin addicts, as well as the differential diagnosis of not only heroin, but also alcohol, sedative and other substances abuse, and all that on the basis of morphological damages of the liver.

Abstract Background.—Hepatocellular carcinoma (HCC) is known to receive its blood supply principally from the hepatic arteries. Recent studies have reported differences in the vascular supply, especially arterial supply among low- and high-grade dysplastic nodules (DNs) (also referred to as adenomatous hyperplasia and macroregenerative nodules) and HCCs. Increased expression of vascular endothelial growth factor (VEGF) has been reported in HCC. In addition, VEGF may play an important role in the early phases of hepatocarcinogenesis. Methods.—We immunohistochemically stained 7 low-grade DNs, 8 high-grade DNs, 11 early HCCs, 17 small HCCs, and 21 advanced HCCs with antibodies against VEGF, α-smooth muscle actin (to identify unpaired arteries, ie, arteries not accompanied by bile ducts, indicative of angiogenesis), CD34 (as a marker of sinusoidal capillarization), and proliferation cell nuclear antigen. Results.—Expression of VEGF was found in the hepatocytes and HCC cells. The degree of VEGF expression increased gradually according to the stepwise development of hepatocarcinogenesis. It was higher in high-grade DNs and early HCCs than in low-grade DNs. The hepatocytes and HCC cells adjacent to peliosis and fibrous septa showed stronger VEGF expression. Angiogenesis, unpaired arteries, and sinusoidal capillarization developed from low-grade DNs and gradually increased. It was highest in HCCs. The proliferation cell nuclear antigen labeling indexes of hepatocytes and HCC cells also increased gradually as hepatocarcinogenesis progressed. Small HCCs showed a higher status of neoangiogenesis and cell proliferation activity than advanced HCCs. The degree of VEGF expression was correlated with angiogenesis and cell proliferation activity. Conclusion.—We conclude that VEGF plays a significant role in angiogenesis, growth, and development of HCC.

Hepatocellular carcinoma (HCC), or primary liver cancer, is the fifth most common cancer worldwide and the third most common cause of cancer mortality (El-Serag 2012). The development of HCC is thought to be a multi-staged process that involves several risk factors including the chronic hepatitis B and C infection, carcinogen exposure, metabolic disease, excessive alcohol consumption and male gender. Accumulation of genetic and epigenetic alterations with DNA-damaged hepatocytes can also contribute to the molecular pathogenesis of HCC. A better understanding of molecular mechanisms associated with HCC could ultimately improve our current strategies for screening and targeted therapy of this disease. Array comparative genomic hybridisation studies in murine diethylnitrosamine (DEN)-induced HCC have identified ccne1 (cyclin E) as a candidate gene associated in accelerated liver carcinogenesis (Teoh et al. 2008). In order to investigate the role of cyclin E and its impact on hepatocyte cell cycle regulation in early HCC development, we employed a well-known and highly reproducible rodent model of DEN-induced hepatocarcinogenesis. C57BL/6J male mice were injected with DEN (10 mg/kg i.p.), age day 12-15. In this model, male animals develop hepatocyte dysplasia at 6 mths and HCC in >90%. Transcript and protein expression of cyclin E was evident as early as 6 mths in dysplastic nodules (DNs), and significantly increased in HCCs. In contrast, there was little or undetectable cyclin E in normal liver and liver surrounding HCCs at all timepoints. Glutathione S transferase-pi form and cyclin E expression co-localised in DNs from liver in mice at 6 and 9 mths. Cyclin E/cdk2 kinase activity was also significantly upregulated in DNs, while increased proliferative activity by cyclin D1 and proliferating cell nuclear antigen (PCNA) in HCCs was observed at 9 mths, a timepoint where there was maximal p53 and p21 tumour suppressor expression. Aberrant cyclin E protein expression, including low molecular weight (LMW) isoforms were detected in HCCs and liver surrounding HCCs. Interestingly, sequencing analyses of p53 revealed a 1093-1361 nucleotide deletion in up to 90% of DNs, causing dysfunctional p53 nuclear localisation and export signalling. Because p53 directly signals to p21, co-immunoprecipitation studies were performed and revealed preferential binding of p21 to cyclin D1, rather than cyclin E, thereby allowing "escape" from the G1/S checkpoint. To directly test whether cyclin E regulates p53 expression in HCCs derived from DEN-treated male mice at 9 mths, we conducted cyclin E knockdown in primary HCC cells. This strategy resulted in increased p53 and p21 expression, as well as significant diminution of Bcl-xL, the p53-induced anti-apoptotic marker. Cell viability tetrazolium/formazan assay was significantly impaired in cyclin E RNAi targeted primary HCC cells. Conversely, chemical inhibition of p53 by pfithrin-α, augmented cyclin E, PCNA and Bcl-xL protein expression whilst cell viability was restored following co-treatment with MG-262, a 26S proteasome inhibitor. In contrast, overexpressing cyclin E in naïve primary hepatocytes enhanced PCNA expression, increased hepatocyte viability, downregulated p53 and its downstream signalling intermediate, p21. We next determined whether miRNA-34, a co-regulator of cyclin E and p53, was instrumental in the reciprocity between cyclin E and p53 as key "drivers"of hepatocarcinogenesis. Dysplastic liver and HCCs obtained from DEN-injected male mice were assayed for miR-34a,b,c. miR-34a and c were significantly upregulated in HCCs and dysplastic liver compared with normal liver. Similar trends were noted for miR-34a,b,c in human hepatitis C-related HCCs when compared with normal human liver. Importantly, this was associated with significantly enhanced cyclin E and p53 mRNA expression in human HCCs compared to normal and cirrhotic liver. In this murine model, there was disproportional and upregulation of functionally active cyclin E, miR-34a,c in DNs and early HCCs with congruent loss of p53 function associated with cell cycle checkpoint failure, diminished apoptosis and increased proliferative drive. In human HCV-related HCCs, miR-34a, p53 and cyclin E transcript levels were universally upregulated. When we performed in vitro experiments in murine primary hepatocytes and primary HCC cells, knocking down or overexpressing cyclin E did not affect miR-34 expression. However, stabilising p53 with MG-262 enhanced miR-34a,c expression (though not significant), whilst inhibiting p53 using pfithrin-α significantly reduced miR-34a,c. miR-34 may provide a plausible link to increased cyclin E expression, activity and increased proliferative drive in dysplastic and neoplastic liver in mice and humans. Gender disparity in human HCC is well described, with a strong male predominance. However, the role of sex hormones in hepatocarcinogenesis remains poorly defined. In order to determine if there are gender differences in the expression of cyclin E, effects on cell cycle regulators and tumour suppressors, dysplastic liver and HCCs were studied in DEN-treated C57BL/6J female mice. These mice displayed a significant reduction in dysplastic hepatocytes compared with intact DEN-treated males at 3, 6 mths, while HCC incidence, number and size of tumours were significantly diminished in females at up to 15 mths. In carcinogen-treated female mice, cyclin E (native and LMW isoforms) protein expression and kinase activity were reduced compared to males at 6-12 mths, with concomitant reduction in hepatocyte proliferation by PCNA and cyclin D1 expression. Unlike male mice, G1/S checkpoint is evident by robust p53-mediated apoptosis. To ascertain if these differences are attributable to the effects of oestradiol/progesterone (E/P) and/or testosterone, we conducted hormonal manipulation studies using the same carcinogen-model by performing ovariectomy in female animals and orchidectomy in male mice, in which some animals received E/P or testosterone supplementation. Castration of DEN-injected male mice resulted in a loss of cyclin E LMW isoforms compared to intact males, diminution of cyclin E kinase activity and phospho-retinoblastoma expression. There was also induction of p53-mediated apoptosis in dysplastic hepatocytes, leading to a reduction in number of DNs by 6 mths. These anti-proliferative and pro-apoptotic effects were magnified by E/P replacement in castrated DEN-treated males. In contrast, testosterone-replacement in ovariectomised-female mice exhibited accelerated hepatocarcinogenesis compared to intact female DEN-treated animals and displayed LMW cyclin E isoforms similar to those detected in DEN-injected intact males. In further analyses, there was increased oestrogen receptor-α (ERα) transcript and protein expression in HCCs derived from DEN-injected intact male mice, and in dysplastic liver from castrated male mice replaced with E/P. E/P replacement and testosterone withdrawal were associated with ERα expression, the loss of cyclin E LMW isoforms, intact cdk2 expression, functional G1/S checkpoint control and induction of p53-mediated apoptotic cell death in preneoplastic hepatocytes. Further, oestrogen (E2) stimulation had varying effects on cell cycle regulation and viability in primary hepatocytes and HCC cells. As there was little to no significant correlation between ERα and its downstream target, c-myc transcript levels, we propose that E2/ERα signalling may be operative via other pathways to subsequently activate p53. These findings open up tantalising avenues to further explore the inter-regulatory signalling pathways between E2/ERα, cell cycle regulators and the tumour suppressor, p53.