Regenerating Liver Tissue Research Articles

Evaluating the mitochondrial structure and gene expression profile of regenerated liver tissues in mice after 85% partial hepatectomy.

Partial hepatectomy (PH) is the primary method used for treating liver injury and transplantation. The regeneration process after hepatectomy requires an adequate energy supply, and mitochondria serve as the primary source of energy. Alterations in genes related to the respiratory chain complex may impact the liver regeneration process. The aim of this study was the changes in mitochondrial structure and mitochondrial function in 85% PH. A PH (up to 85%) model was developed using male C57BL/6 mice, and the regenerated liver tissue was harvested after 24 hours. Hematoxylin and eosin staining and transmission electron microscopy were used for morphological studies. In terms of proliferation, a positive proliferating cell nuclear antigen (PCNA) rate was detected via immunohistochemistry. Real-time polymerase chain reaction was performed to identify differentially expressed genes (DEGs), which were screened using a P value of <0.05 and a |fold change| of ≥1.5. The Hiplot online tool was used for generating a volcano plot and conducting correlation analyses. R software was employed for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses for the DEGs. A combined Search Tool for the Retrieval of Interacting Genes/Proteins (STRING)-Cytoscape method was used for protein-protein interaction (PPI) network analyses, whereas cytoHubba was used to the screen core DEGs. After 85% PH, we observed steatosis, an increased PCNA positivity rate, mitochondrial swelling, and a reduced number of cristae due to cristae disintegration. We screened 30 DEGs that were associated with different processes, including oxidation-reduction, oxidoreductase activity, electron transfer activity, organelle envelope, inner mitochondrial membrane processes, and oxidative phosphorylation as well as those involved in nonalcoholic fatty liver disease (NAFLD). We identified a total of six hub genes: COX4I1, ATP5B, UQCRC2, CYC1, ATP5O, and ATP5A1. The 85% PH model promotes mitochondrial complex protein expression, thereby providing energy for liver regeneration. The enriched genes were associated with oxidation-reduction, electron transfer activity, and inner mitochondrial membrane processes.

Unsaturated or saturated dietary fat-mediated steatosis impairs hepatic regeneration following partial hepatectomy in mice.

Partial hepatectomy is a preferred treatment option for many patients with hepatocellular carcinoma however, pre-existing pathological abnormalities originating from hepatic steatosis can alter the decision to perform surgery or postoperative outcomes as a consequence of the impact steatosis has on liver regeneration. The aim of this study was to investigate the role of a saturated or unsaturated high fat diet-mediated steatosis on liver regeneration following partial hepatectomy. Mice were fed a low-fat control diet (CD, 13% fat), lard-based unsaturated (LD, 60% fat) or milk-based saturated high fat diet (MD, 60% fat) for 16 weeks at which time partial hepatectomy (approx. 70% resection) was performed. At days-2 and 7 post hepatectomy, one hour prior to euthanization, mice were injected with 5-bromo-2'-deoxyuridine in order to monitor hepatic regeneration. Serum was collected and assessed for levels of ALT and AST. Resected and regenerated liver tissue were examined for inflammation-indicative markers employing RT-PCR, Western blots, and histological methods. Mice fed LD or MD exhibited higher NAFLD scores, increased expression of inflammatory cytokines, neutrophil infiltration, macrophage accumulation, increased apoptosis, and elevated levels of serum ALT and AST activities, a decrease in the number of BrdU-incorporated-hepatocytes in the regenerated livers compared to the mice fed CD. Mice fed MD showed significantly lower percent of BrdU-incorporated hepatocytes and a higher trend of inflammation compared to the mice fed LD. A diet rich in saturated or unsaturated fat results in NASH with decreased hepatic regeneration however unsaturated fat diet cause lower inflammation and higher regeneration than the saturated fat diet following partial hepatectomy in mice.

Bevacizumab Does Not Inhibit the Formation of Liver Vessels and Liver Regeneration Following Major Hepatectomy: A Large Animal Model Study.

Patients with unresectable liver colorectal cancer metastases are treated with neoadjuvant chemotherapy often accompanied by biological therapy aimed at reducing the mass of metastases and thus increasing the chances of resectability. Bevacizumab comprises an anti-VEGF (vascular endothelial growth factor) humanized IgG monoclonal antibody that is used for biological therapy purposes. It acts to inhibit angiogenesis, thereby slowing down the growth of metastases. Due to its being administered systematically, bevacizumab also exerts an effect on the surrounding healthy liver parenchyma and potentially limits the process of neovascularization and thus regeneration of the liver. Since the remnant liver volume forms an important factor in postoperative morbidity and mortality following a major hepatectomy, we decided to study the effect of bevacizumab on vascular and biliary microarchitecture in healthy liver parenchyma and its ability to regenerate following major hepatectomy. We performed an experiment employing a large animal model where a total of 16 piglets were divided into two groups (8 piglets in the control group and 8 piglets in the experimental group with bevacizumab). All the animals were subjected to major hepatectomy and the experimental group was given bevacizumab prior to hepatectomy. All the animals were sacrificed after 4 weeks. We performed biochemical analyses at regular time intervals during the follow-up period. Histological examination of the liver tissue was performed following sacrifice of the animals. No statistical difference was shown between groups in terms of the biochemical and immunohistochemical parameters. The histological examination of the regenerating liver tissue revealed the higher length density of sinusoids in the experimental group. Bevacizumab does not act to impair liver regeneration following hepatectomy.

Astragaloside IV Suppresses Hepatic Proliferation in Regenerating Rat Liver after 70% Partial Hepatectomy via Down-Regulation of Cell Cycle Pathway and DNA Replication.

Astragaloside IV (AS-IV) is one of the major bio-active ingredients of huang qi which is the dried root of Astragalus membranaceus (a traditional Chinese medicinal plant). The pharmacological effects of AS-IV, including anti-oxidative, anti-cancer, and anti-diabetic effects have been actively studied, however, the effects of AS-IV on liver regeneration have not yet been fully described. Thus, the aim of this study was to explore the effects of AS-IV on regenerating liver after 70% partial hepatectomy (PHx) in rats. Differentially expressed mRNAs, proliferative marker and growth factors were analyzed. AS-IV (10 mg/kg) was administrated orally 2 h before surgery. We found 20 core genes showed effects of AS-IV, many of which were involved with functions related to DNA replication during cell division. AS-IV down-regulates MAPK signaling, PI3/Akt signaling, and cell cycle pathway. Hepatocyte growth factor (HGF) and cyclin D1 expression were also decreased by AS-IV administration. Transforming growth factor β1 (TGFβ1, growth regulation signal) was slightly increased. In short, AS-IV down-regulated proliferative signals and genes related to DNA replication. In conclusion, AS-IV showed anti-proliferative activity in regenerating liver tissue after 70% PHx.

Mesenchymal Stromal Cell Therapy in Novel Porcine Model of Diffuse Liver Damage Induced by Repeated Biliary Obstruction.

In liver surgery, biliary obstruction can lead to secondary biliary cirrhosis, a life-threatening disease with liver transplantation as the only curative treatment option. Mesenchymal stromal cells (MSC) have been shown to improve liver function in both acute and chronic liver disease models. This study evaluated the effect of allogenic MSC transplantation in a large animal model of repeated biliary obstruction followed by partial hepatectomy. MSC transplantation supported the growth of regenerated liver tissue after 14 days (MSC group, n = 10: from 1087 ± 108 (0 h) to 1243 ± 92 mL (14 days); control group, n = 11: from 1080 ± 95 (0 h) to 1100 ± 105 mL (14 days), p = 0.016), with a lower volume fraction of hepatocytes in regenerated liver tissue compared to resected liver tissue (59.5 ± 10.2% vs. 70.2 ± 5.6%, p < 0.05). Volume fraction of connective tissue, blood vessels and bile vessels in regenerated liver tissue, serum levels of liver enzymes (AST, ALT, ALP and GGT) and liver metabolites (albumin, bilirubin, urea and creatinine), as well as plasma levels of IL-6, IL-8, TNF-α and TGF-β, were not affected by MSC transplantation. In our novel, large animal (pig) model of repeated biliary obstruction followed by partial hepatectomy, MSC transplantation promoted growth of liver tissue without any effect on liver function. This study underscores the importance of translating results between small and large animal models as well as the careful translation of results from animal model into human medicine.

Machine Perfusion of the Liver: A Review of Clinical Trials.

Although efforts have been made by transplant centers to increase the pool of available livers by extending the criteria of liver acceptance, this practice creates risks for recipients that include primary non-function of the graft, early allograft dysfunction and post-operative complications. Donor liver machine perfusion (MP) is a promising novel strategy that not only decreases cold ischemia time, but also serves as a method of assessing the viability of the graft. In this review, we summarize the data from liver machine perfusion clinical trials and discuss the various techniques available to date as well as future applications of machine perfusion. A variety of approaches have been reported including hypothermic machine perfusion (HMP) and normothermic machine perfusion (NMP); the advantages and disadvantages of each are just now beginning to be resolved. Important in this effort is developing markers of viability with lactate being the most predictive of graft functionality. The advent of machine perfusion has also permitted completely ischemia free transplantation by utilization of in situ NMP showed promising results. Animal studies that focus on defatting steatotic livers via NMP as well as groups that work on regenerating liver tissue ex vivo via MP. The broad incorporation of machine perfusion into routine clinical practice seems incredible.

NAIP expression increases in a rat model of liver mass restoration.

The neuronal apoptosis inhibitory protein (NAIP) is a constituent of the NLRC4 inflammasome, which plays a key role in innate immunity, and an antiapoptotic protein. Recently, we reported the previously undescribed role of NAIP in cell division. The liver is one of the body's most actively regenerative organs. Given the novel mitotic role of NAIP, we examined its expression in hepatic mass restoration. The major liver lobe of Wistar rats was removed, and samples from both newly formed liver tissue, assessed by positive Ki67 immunostaining, and the remnant, intact liver lobes from hepatectomized rats were taken 3 and 7days after surgery. Naip5 and Naip6 mRNA levels were significantly higher in regenerating hepatic tissue than in intact liver lobe tissue, and this increase was also observed at the protein level. Naip5 and Naip6 mRNA in situ hybridization showed that this increase occurred in the hepatic parenchyma. The histology of the regenerated liver tissue was normal, with the exception of a noticeable deficiency of hepatic lobule central veins. The results of this study suggest the involvement of NAIP in liver mass restoration following partial hepatectomy.

Hepatic stellate cells contribute to liver regeneration through galectins in hepatic stem cell niche

BackgroundAs a critical cellular component in the hepatic stem cell niche, hepatic stellate cells (HSCs) play critical roles in regulating the expansion of hepatic stem cells, liver regeneration, and fibrogenesis. However, the signaling of HSCs, particularly that involved in promoting hepatic stem cell expansion, remains unclear. While the overexpression of galectins has been identified in regenerating liver tissues, their involvement in cell-cell interactions between HSCs and hepatic stem cells remains to be elucidated.MethodsTo generate a liver regeneration rat model and establish a hepatic oval cell microenvironment as a stem cell niche, 2-acetylaminofluorene treatment plus partial hepatectomy was performed. Immunofluorescence staining was conducted to detect the emergence of hepatic stem cells and their niche. Liver parenchymal cells, non-parenchymal cells, and HSCs were isolated for gene and protein expression analysis by qPCR or western blotting. To evaluate the effect of galectins on the colony-forming efficiency of hepatic stem cells, c-Kit−CD29+CD49f+/lowCD45−Ter-119− cells were cultured with recombinant galectin protein, galectin antibody, galectin-producing HSCs, and galectin-knockdown HSCs.ResultsFollowing liver injury, the cytokeratin 19+ ductal cells were robustly induced together with the emergence of OV6+CD44+CD133+EpCAM+ hepatic stem cells. The activated desmin+ HSCs were recruited around the periportal area and markedly enriched in the galectin-positive domain compared to the other non-parenchymal cells. Notably, the HSC fraction isolated from regenerating liver was accompanied by dramatically elevated gene and protein expression of galectins. Hepatic stem cells co-cultured with HSCs significantly enhanced colony-forming efficiency. Conversely, single or double knockdown of galectin-1 and galectin-3 led into a significant function loss, impaired the co-cultured hepatic stem cells to attenuated colony size, inhibited colony frequency, and reduced total cell numbers in colonies. On the other hand, the promotive function of galectins was further confirmed by recombinant galectin protein supplementation and galectins blocking antibodies.ConclusionsOur findings, for the first time, demonstrated that galectins from activated HSCs contribute to hepatic stem cell expansion during liver regeneration, suggesting that galectins serve as important stem cell niche components.

A comparative study of the effect of irreversible electroporation and radiofrequency ablation on rat liver neovascularization

Objective To investigate the difference of hepatic microvessel density, neovascularization of regenerating liver tissue after ablation of two ways of irreversible electroporation and radiofrequency ablation in rats. Methods 90 male Sprague-Dawley rats were randomly divided into 3 groups, including the control group (n=30), the irreversible electroporation group (n=30) and the radiofrequency ablation group (n=30). 3, 7 and 10 days were executed after the operation and draw material, expression of vascular endothelial growth factor(VEGF) and CD34 in tissue was studied by immunohistochemistry, and the microvascular density of tissue and VEGF positive cells were measured. Results The microvascular density of 3, 7 and 10 days in the control group was 50.3±12.5, 54.6±11.9 and 58.2±14.7, the microvascular density of the radiofrequency ablation group was 18.4±4.7, 17.3±5.1 and 18.1±5.9, respectively. The microvascular density of the irreversible electroporation group was 42.8±10.4, 45.6±10.2 and 49.2±13.8, respectively. The positive cells of VEGF in control group was 50, 56 and 57 at 3, 7 and 10 days, and 32, 30 and 33 at 3, 7 and 10 days in radiofrequency ablation group, 44, 43 and 45 at 3, 7 and 10 days in irreversible electroporation group; expression of VEGF and CD34 in 3, 7, 10 d and the microvascular density of ablation area in radiofrequency ablation group was significantly lower than those in control group after irreversible electroporation and radiofrequency ablation. No significant differences were found between irreversible electroporation group and control group. Conclusion The irreversible electroporation can effectively protect the microvessels in the ablation area, ensure the tissue’s blood supply after the ablation, and provide a guarantee for the repair and regeneration of the tissue. Key words: Liver; Ablation techniques; Electroporation; Neovascularization

Optimized Ki-67 staining in murine cells: a tool to determine cell proliferation.

The reliable analysis of the cell cycle status has become increasingly relevant for scientific and clinical work, especially for the determination of tumor cell growth. One established method to characterize the proliferation activity of cells is the analysis of the Ki-67 protein. Ki-67 is expressed in the nucleus during the whole cell cycle except for the G0 phase. Several different protocols exist for the examination of the Ki-67 protein in tissue and cell culture, but most of them are defined for human cells. For the analysis of the Ki-67 protein in murine tissue and cell culture there is a variety of protocols existing which recommend different fixation and permeabilization reagents or special kits. In this study, we established a reliable protocol for Ki-67 staining in murine cells and tissue based on PFA fixation, which can be used not only for flow cytometry but also for immunofluorescence microscopy analysis. We tested our protocol successfully with three different Ki-67 anti-mouse antibodies in cell culture, regenerating liver tissue and mouse melanoma tumor to demonstrate the general applicability.

The basis of liver regeneration: A systems biology approach

IntroductionLiver regeneration is a normal response to liver injury. The aim of this study was to determine the molecular basis of liver regeneration, through an integrative analysis of high-throughput gene expression datasets. MethodsWe identified and curated datasets pertaining to liver regeneration from the Gene Expression Omnibus, where regenerating liver tissue was compared to healthy liver samples. The key dysregulated genes and pathways were identified using Ingenuity Pathway Analysis software. There were three eligible datasets in total. ResultsIn the early phase after hepatectomy, inflammatory pathways such as Nrf2 oxidative stress-mediated response and cytokine signaling were significantly upregulated. At peak regeneration, we discovered that cell cycle genes were predominantly expressed to promote cell proliferation. Using the Betweenness centrality algorithm, we discovered that Jun is the key central gene in liver regeneration. Calcineurin inhibitors may inhibit liver regeneration, based on predictive modeling. ConclusionThere is a paucity of human literature in defining the molecular mechanisms of liver regeneration along a time continuum. Nonetheless, using an integrative computational analysis approach to the available high-throughput data, we determine that the oxidative stress response and cytokine signaling are key early after hepatectomy, whereas cell cycle control is important at peak regeneration. The transcription factor Jun is central to liver regeneration and a potential therapeutic target. Future studies of regeneration in humans along a time continuum are needed to better define the underlying mechanisms, and ultimately enhance care of patients with acute and chronic liver failure while awaiting transplant.

Subcutaneous Inoculation of Echinococcus multilocularis Induces Delayed Regeneration after Partial Hepatectomy

Alveolar echinococcosis (AE) is caused by the larval stage of echinococcus multilocularis (E. multilocularis), and hepatectomy is the main modality in hepatic AE patients. Liver regeneration after partial hepatectomy (PHx) in such patients is challenging, and further investigation is needed. Thus far, knowledge regarding the possible impact of E. multilocularis on liver regeneration after PHx is limited. Herein, a subcutaneous infection model of E. multilocularis was developed in C57 BL/6 mice, and after 3 months, PHx was performed. Plasma and liver samples were harvested under inhalational isofluorane (2%) anaesthesia at designated post-PHx time points (0, 24, 48, 96 and 168 h). The parameters included the future remnant liver/body weight ratio (FLR/BW), liver function tests (AST and ALT) and related cytokines (TNF-α, IL-6, Factor V, HMGB1, TGF-β, TSP-1, and TLR4) and proteins (MyD88 and STAT3). To assess the proliferation intensity of hepatocytes, BrdU, Ki67 and PAS staining were carried out in regenerated liver tissue. The FLR/BW in the infected group from 48 h after surgery was lower than that in the control group. The BrdU positive hepatocyte proportions reached their peak at 48 h in the control group and 96 h in the infected group and then gradually decreased. During the first 48 h after surgery, both the AST and ALT levels in the infected group were lower; however, these levels were altered from 96 h after surgery. In the infected group, the concentrations and mRNA expression levels of the pre-inflammatory cytokines TNF-α and IL-6 demonstrated a delayed peak. Moreover, post-operatively, the TGF-β and TSP-1 levels showed high levels in the infected group at each different time-point compared to those in the control group; however, high levels of TGF-β were observed at 96 h in the control group. The MyD88 and STAT3 protein expression levels in the infected group were markedly higher than those in the control group 96 h after surgery. Delayed liver regeneration after PHx was observed in the C57 BL/6 mice with the subcutaneous infection of E. multilocularis in the current study. This phenomenon could be partially explained by the alteration in the pro-inflammatory cytokines in the immunotolerant milieu induced by chronic E. multilocularis infection.

Loss of BCAA Catabolism during Carcinogenesis Enhances mTORC1 Activity and Promotes Tumor Development and Progression

Tumors display profound changes in cellular metabolism, yet how these changes aid the development and growth of tumors is not fully understood. Here we use a multi-omic approach to examine liver carcinogenesis and regeneration, and find that progressive loss of branched-chain amino acid (BCAA) catabolism promotes tumor development and growth. In human hepatocellular carcinomas and animal models of liver cancer, suppression of BCAA catabolic enzyme expression led to BCAA accumulation in tumors, though this was not observed in regenerating liver tissues. The degree of enzyme suppression strongly correlated with tumor aggressiveness, and was an independent predictor of clinical outcome. Moreover, modulating BCAA accumulation regulated cancer cell proliferation invitro, and tumor burden and overall survival invivo. Dietary BCAA intake in humans also correlated with cancer mortality risk. In summary, loss of BCAA catabolism in tumors confers functional advantages, which could be exploited by therapeutic interventions in certain cancers.

The Basis of Liver Regeneration: A Systems Biology Approach

Introduction and aim. Liver regeneration is a normal response to liver injury. The aim of this study was to determine the molecular basis of liver regeneration, through an integrative analysis of high-throughput gene expression datasets. Material and methods. We identified and curated datasets pertaining to liver regeneration from the Gene Expression Omnibus, where regenerating liver tissue was compared to healthy liver samples. The key dysregulated genes and pathways were identified using Ingenuity Pathway Analysis software. There were three eligible datasets in total. Results. In the early phase after hepatectomy, inflammatory pathways such as Nrf2 oxidative stress-mediated response and cytokine signaling were significantly upregulated. At peak regeneration, we discovered that cell cycle genes were predominantly expressed to promote cell proliferation. Using the Betweenness centrality algorithm, we discovered that Jun is the key central gene in liver regeneration. Calcineurin inhibitors may inhibit liver regeneration, based on predictive modeling. Conclusion. There is a paucity of human literature in defining the molecular mechanisms of liver regeneration along a time continuum. Nonetheless, using an integrative computational analysis approach to the available high-throughput data, we determine that the oxidative stress response and cytokine signaling are key early after hepatectomy, whereas cell cycle control is important at peak regeneration. The transcription factor Jun is central to liver regeneration and a potential therapeutic target. Future studies of regeneration in humans along a time continuum are needed to better define the underlying mechanisms, and ultimately enhance care of patients with acute and chronic liver failure while awaiting transplant.

Ubiquitin‑like protein FAT10 regulates DNA damage repair via modification of proliferating cell nuclear antigen.

In response to DNA damage, proliferating cell nuclear antigen (PCNA) has an important role as a positive regulator and as a scaffold protein associated with DNA damage bypass and repair pathways by serving as a platform for the recruitment of associated components. As demonstrated in the present study, the ubiquitin-like modifier human leukocyte antigen F locus adjacent transcript 10 (FAT10), which binds to PCNA but has not previously been demonstrated to be associated with the DNA damage response (DDR), is induced by ultraviolet/ionizing radiation and VP-16 treatment in HeLa cells. Furthermore, DNA damage enhances FAT10 expression. Immunoprecipitation analysis suggested PCNA is modified by FAT10, and the degradation of FATylated PCNA located in the cytoplasm is regulated by the 26S proteasome, which is also responsible for the upregulation of nuclear foci formation. Furthermore, immunofluorescence experiment suggested FAT10 co-localizes with PCNA in nuclear foci, thus suggesting that FATylation of PCNA may affect DDR via the induction of PCNA degradation in the cytoplasm or nucleus. In addition, immunohistochemistry experiment suggested the expression levels of FAT10 and PCNA are enhanced in HCC tissues compared with healthy liver tissues; however, the expression of FAT10 is suppressed in regenerated liver tissues, which express high levels of PCNA, thus suggesting that the association between FAT10 and PCNA expression is only exhibited in tumor tissues. In conclusion, the results of the present study suggest that FAT10 may be involved in DDR and therefore the progression of tumorigenesis.

Effects of pharmacological inhibition of plasminogen binding on liver regeneration in rats.

The fibrinolysis system is thought to play an important role in liver regeneration. We previously found that plasminogen (Plg) is localized to the cell surface of regenerating liver tissue as well as proliferating hepatocytes in vitro. Here, we investigated the significance of Plg binding to the cell surface during liver regeneration. Pre-administration of tranexamic acid (TXA), which is a competitive inhibitor of Plg binding, to hepatectomized rats mildly delayed restoration of liver weight in vivo. Although binding of Plg to the cell membrane decreased following TXA administration, TXA showed little effect on hepatocyte proliferation in rats. We also discovered that Plg treatment did not stimulate proliferation of primary rat hepatocytes in vitro. These results suggest that Plg/plasmin potentiates liver regeneration via a pathway distinct from those through which hepatocyte proliferation is stimulated.

Preliminary profiling of microRNA in the normal and regenerating liver of Chiloscyllium plagiosum

Liver is a vital organ present in animals for detoxification, protein synthesis, digestion and other functions and its powerful regenerative capacity is well known. C. plagiosum is an abundant fish that is representative of the cartilaginous class in the southeast coastal region of China and its liver accounts for >70% of the fish's visceral weight and contains many bioactive substances. MicroRNAs (microRNAs) play important roles in a wide range of biological processes in eukaryotes, including cell proliferation, differentiation, apoptosis. However, microRNAs in response to liver regeneration has not been well studied. This study aimed to identify the microRNAs that participate in liver regeneration and other liver-related diseases and to improve our understanding of the mechanisms of liver regeneration in sharks. To this end, normal and regenerating liver tissues from C. plagiosum were harvested 0, 3, 6, 12 and 24h after partial hepatectomy (pH) and were sequenced using the Illumina/Solexa platform. In total, 309 known microRNAs and 590 novel microRNAs were identified in C. plagiosum. There were many microRNAs differentially expressed in the normal and regenerating livers between time points. Using target prediction and GO analysis, most of the differentially expressed microRNAs were assigned to functional categories that may be involved in regulating liver regeneration, such as cell proliferation, differentiation and apoptosis. The microRNA expression profile of liver regeneration will pave the way for the development of effective strategies to fight against liver disease and other related disease.

Hepatocyte growth factor and epidermal growth factor activity during later stages of rat liver regeneration upon interferon α-2b influence.

IntroductionLiver regeneration is a complex, highly coordinated process which can be disturbed by the impact of the anti-proliferative interferon α activity. In the model of partial hepatectomy (PH) in the rat the expression of HGF and EGF genes and their molecules’ tissue concentrations were analyzed in the later stages of liver regeneration (48-120 h).Material and methods40 three-month-old male Wistar rats were randomized to groups of 20 animals each. The rats of the study group (IFN/H) were injected subcutaneously with IFNα-2b, while the control group was injected with 0.5 ml of 0.9% NaCl (NaCl/H). In the liver tissue samples obtained during hepatectomy and autopsy (regenerating liver mass) the expression of HGF and EGF genes was estimated with the Q-PCR method and the analysis of HGF and EGF molecule concentrations in tissue homogenates was conducted with the ELISA method.ResultsHGF but not EGF expression was significantly higher at 48 h after PH, while EGF expression was higher in normal than in regenerating liver tissue at 120 h. The analyses of correlations between expression of HGF and EGF in regenerating liver tissue, both normal and upon IFNα-2b influence, together with correlations between those factors genes’ expression and HGF and EGF tissue concentrations in analyzed samples, showed no significant differences.ConclusionsHGF and EGF are not significantly involved in regulation of later stages of rat liver regeneration. IFNα-2b does not impact expression of their genes or the presence of these growth factor molecules in regenerating liver tissue.

Biomaterials and Culture Technologies for Regenerative Therapy of Liver Tissue.

Regenerative approach has emerged to substitute the current extracorporeal technologies for the treatment of diseased and damaged liver tissue. This is based on the use of biomaterials that modulate the responses of hepatic cells through the unique matrix properties tuned to recapitulate regenerative functions. Cells in liver preserve their phenotype or differentiate through the interactions with extracellular matrix molecules. Therefore, the intrinsic properties of the engineered biomaterials, such as stiffness and surface topography, need to be tailored to induce appropriate cellular functions. The matrix physical stimuli can be combined with biochemical cues, such as immobilized functional groups or the delivered actions of signaling molecules. Furthermore, the external modulation of cells, through cocultures with nonparenchymal cells (e.g., endothelial cells) that can signal bioactive molecules, is another promising avenue to regenerate liver tissue. This review disseminates the recent approaches of regenerating liver tissue, with a focus on the development of biomaterials and the related culture technologies.

The Impact of Tumor Cell Proliferation on Occult Micrometastases, Tumor Recurrence and Patient Outcome Following Resection for Liver Malignancies

Liver resection is currently considered to be essential part of the curative treatment of primary and secondary liver malignancies. However, long-term survival in these patients is limited by the high incidence of tumor recurrence. Recent clinical and experimental studies have indicated that cellular and molecular mechanisms associated with liver regeneration after partial hepatectomy may have a proliferative effect on occult micrometastases and circulating tumor cells and are thus responsible for recurrent disease. Growth factors and cytokines involved in liver regeneration have also been shown to influence tumour growth and metastasis. However, the underlying mechanisms explaining the interactions between regenerating liver tissue and tumour cell proliferation remain unclear. The development of modern agents specifically targeting these processes may improve disease-free and overall survival rates after oncological hepatectomy.