Preservation Efficacy of a Quercetin and Sucrose Solution for Warm Ischemically Damaged Porcine Liver Grafts

BACKGROUND

The University of Wisconsin (UW) solution is the gold standard for preserving the liver, kidneys, and pancreas. For renal preservation, the addition of the flavonoid, quercetin (QE), to the preservation solution reduces damage to renal tubular cells, and the addition of sucrose (Suc) is also beneficial for preservation. The aim of this study was to investigate the protective effects of QE and Suc on porcine livers in terms of warm and cold injury and to evaluate whether their use improves ischemia-reperfusion (I/R) injury after simple cold storage (CS).

METHODS

We tested porcine livers procured after 30 minutes of warm ischemia followed by preservation for 6 hours under the following 2 conditions: group 1, preserved with the CS/UW solution (n = 4); group 2, preserved with the CS/UW solution containing Que 33.1 μM and Suc 0.1 M (n = 6). All livers were evaluated using an ex vivo isolated liver reperfusion model with saline-diluted autologous blood.

RESULTS

Aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase levels in group 2 were significantly lower at 30 minutes of reperfusion than in group 1. Furthermore, histologic evaluation by hematoxylin and eosin staining showed significantly fewer morphologic changes in group 2 than in group 1, as indicated by the total Suzuki score. Group 2 also had significantly better scores for sinusoidal congestion and hepatocyte cytoplasmic vacuolization.

CONCLUSION

Adding Que and Suc to the UW solution can effectively prevent cold injury in livers donated after circulatory death.

An orally deliverable ornithine-based self-assembling polymer nanomedicine ameliorates hyperammonemia in acetaminophen-induced acute liver injury

l-Ornithine (Orn) is a core amino acid responsible for ammonia detoxification in the body via the hepatic urea cycle. Clinical studies in Orn therapy have focused on interventions for hyperammonemia-associated diseases, such as hepatic encephalopathy (HE), a life-threatening neurological symptom affecting more than 80% of patients with liver cirrhosis. However, its low molecular weight (LMW) causes Orn to diffuse nonspecifically and be rapidly eliminated from the body after oral administration, resulting in unfavorable therapeutic efficacy. Hence, Orn is constantly supplied by intravenous infusion in many clinical settings; however, this treatment inevitably decreases patient compliance and limits its application in long-term management. To improve the performance of Orn, we designed self-assembling polyOrn-based nanoparticles for oral administration through ring-opening polymerization of Orn-N-carboxy anhydride initiated with amino-ended poly(ethylene glycol), followed by acylation of free amino groups in the main chain of the polyOrn segment. The obtained amphiphilic block copolymers, poly(ethylene glycol)-block-polyOrn(acyl) (PEG-block-POrn(acyl)), enabled the formation of stable nanoparticles (NanoOrn(acyl)) in aqueous media. We employed the isobutyryl (iBu) group for acyl derivatization in this study (NanoOrn(iBu)). In the healthy mice, daily oral administration of NanoOrn(iBu) for one week did not induce any abnormalities. In the mice exhibiting acetaminophen (APAP)-induced acute liver injury, oral pretreatment with NanoOrn(iBu) effectively reduced systemic ammonia and transaminases levels compared to the LMW Orn and untreated groups. The results suggest that the application of NanoOrn(iBu) is of significant clinical value with the feasibility of oral delivery and improvement in APAP-induced hepatic pathogenesis. STATEMENT OF SIGNIFICANCE: Liver injury is often accompanied by hyperammonemia, a life-threatening condition characterized by elevated blood ammonia levels. Current clinical treatments for reducing ammonia typically entail the invasive approach of intravenous infusion, involving the administration of l-ornithine (Orn) or a combination of Orn and L-aspartate. This method is employed due to the poor pharmacokinetics associated with these compounds. In our pursuit of enhancing therapy, we have developed an orally administrable nanomedicine based on Orn-based self-assembling nanoparticle (NanoOrn(iBu)), which provides sustained Orn supply to the injured liver. Oral administration of NanoOrn(iBu) to healthy mice did not cause any toxic effects. In a mouse model of acetaminophen-induced acute liver injury, oral administration of NanoOrn(iBu) surpassed Orn in reducing systemic ammonia levels and liver damage, thereby establishing NanoOrn(iBu) as a safe and effective therapeutic option.

Dyrk2 gene transfer suppresses hepatocarcinogenesis by promoting the degradation of Myc and Hras

Background & Aims

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide, and has a poor prognosis. However, the molecular mechanisms underlying hepatocarcinogenesis and progression remain unknown. In vitro gain- and loss-of-function analyses in cell lines and xenografts revealed that dual-specificity tyrosine-regulated kinase 2 (DYRK2) influences tumour growth in HCC.

Methods

To investigate the role of Dyrk2 during hepatocarcinogenesis, we developed liver-specific Dyrk2 conditional knockout mice and an in vivo gene delivery system with a hydrodynamic tail vein injection and the Sleeping Beauty transposon. The antitumour effects of Dyrk2 gene transfer were investigated in a murine autologous carcinogenesis model.

Results

Dyrk2 expression was reduced in tumours, and that its downregulation was induced before hepatocarcinogenesis. Dyrk2 gene transfer significantly suppressed carcinogenesis. It also suppresses Myc-induced de-differentiation and metabolic reprogramming, which favours proliferative, and malignant potential by altering gene profiles. Dyrk2 overexpression caused Myc and Hras degradation at the protein level rather than at the mRNA level, and this degradation mechanism was regulated by the proteasome. Immunohistochemical analyses revealed a negative correlation between DYRK2 expression and MYC and longer survival in patients with HCC with high-DYRK2 and low-MYC expressions.

Conclusions

Dyrk2 protects the liver from carcinogenesis by promoting Myc and Hras degradation. Our findings would pave the way for a novel therapeutic approach using DYRK2 gene transfer.

Impact and Implications

Hepatocellular carcinoma (HCC) is one of the most common cancers, with a poor prognosis. Hence, identifying molecules that can become promising targets for therapies is essential to improve mortality. No studies have clarified the association between DYRK2 and carcinogenesis, although DYRK2 is involved in tumour growth in various cancer cells. This is the first study to show that Dyrk2 expression decreases during hepatocarcinogenesis and that Dyrk2 gene transfer is an attractive approach with tumour suppressive activity against HCC by suppressing Myc-mediated de-differentiation and metabolic reprogramming that favours proliferative and malignant potential via Myc and Hras degradation.

Hepatocyte-specific damage in acute toxicity of sodium ferrous citrate: Presentation of a human autopsy case and experimental results in mice

Acute iron overload is known to exert deleterious effects in the liver, but detailed pathology has yet to be documented. Here, we report pathological findings in an autopsy case of acute iron toxicity and validation of the findings in mouse experiments. In a 39-year-old woman who intentionally ingested a large amount of sodium ferrous citrate (equivalent to 7.5 g of iron), severe disturbance of consciousness and fulminant hepatic failure rapidly developed. Liver failure was refractory to treatment and the patient died on Day 13. Autopsy revealed almost complete loss of hepatocytes, while bile ducts were spared. To examine the detailed pathologic processes induced by excessive iron, mice were orally administered equivalent doses of ferrous citrate. Plasma aminotransferase levels markedly increased after 6 h, which was preceded by increased plasma iron levels. Hepatocytes were selectively damaged, with more prominent damage in the periportal area. Phosphorylated c-Jun was detected in hepatocyte nuclei after 3 h, which was followed by the appearance of γ-H2AX expression. Hepatocyte injury in mice was associated with the expression of Myc and p53 after 12 and 24 h, respectively. Even at lethal doses, the bile ducts were morphologically intact and fully viable. Our findings indicate that acute iron overload induces hepatocyte-specific liver injury, most likely through hydroxyl radical-mediated DNA damage and subsequent stress responses.

Self-assembling polymer-based short chain fatty acid prodrugs ameliorate non-alcoholic steatohepatitis and liver fibrosis

With the preponderance of a high-calorie diet and sedentary lifestyle, the prevalence of non-alcoholic steatohepatitis (NASH), a state of abnormally elevated lipid accumulation in the liver with chronic inflammation, is increasing at an alarming rate worldwide. Hence, cost-effective therapeutic interventions are required to manage this disease at an early stage. Numerous reports have suggested a link between gut microbial dysbiosis, particularly a decrease in the abundance of short-chain fatty acids (SCFA)-producing microbiota and NASH pathogenesis. Considering these low molecular weight (LMW) SCFAs such as acetic, propionic, and butyric acids have been used to inhibit hepatic steatosis in mouse models. However, the poor pharmacokinetic (PK) profile of SCFAs, caused due to their LMW, renders them therapeutically ineffective. Thus, to improve the PK characteristic-based therapeutic efficacy of LMW SCFAs, we designed SCFA-based prodrugs that possess self-assembling characteristics in aqueous media. The designed SCFA prodrugs consist of enzyme-metabolizable amphiphilic block copolymers, [poly(ethylene glycol)-b-poly(vinyl ester)s] conjugated to propionic acid (PA) or butyric acid (BA) by an ester linkage, which self-assemble into stable nanosized micelles several tens of nanometers in diameter (Nano^PA and Nano^BA). Via pharmacological analysis, we confirmed that, after oral administration, LMW BA decreased to a physiological level within 24 h in the liver, whereas BA liberated from Nano^BA was observed until 72 h post-administration, implying a sustained release profile. Here, we evaluated the therapeutic efficacy of Nano^SCFA in a choline-deficient, L-amino acid-defined high-fat diet (CDAHFD)-induced NASH and liver fibrosis mouse model by ad libitum drinking. Nano^SCFA, particularly Nano^BA, exhibited the remarkable potential to ameliorate the phenotypic features of fatty liver disease by reducing hepatic lipogenesis and fibrosis, with negligible adverse effects. In contrast, conventional LMW SCFAs failed to prevent the pathogenesis of fatty liver disease, which plausibly can be explained by their rapid clearance and discernible adverse effects. Mechanistic studies revealed that Nano^BA restored the nuclear expression of PPARα, a transcriptional factor regulating mitochondrial fatty acid oxidation, in the periportal hepatocytes and decreased the CPT1A expression level in the hepatic tissues, reflecting the therapeutic effects of Nano^BA. Taken together, we confirmed that our Nano^SCFA potentially improved the PK properties of SCFAs, and it consequently alleviated NASH symptoms and fibrotic liver compared to LMW SCFAs. Our study establishes Nano^SCFA as a suitable nano-assembled prodrug for NASH treatment.

Applicability of the histidine-tryptophan-ketoglutarate solution as a machine perfusion solution for marginal liver grafts

BACKGROUND AND AIM

There are very few reports comparing the use of the University of Wisconsin solution and histidine-tryptophan-ketoglutarate solution as machine perfusion solutions for marginal liver grafts. We aimed to clarify whether the use of the histidine-tryptophan-ketoglutarate solution in hypothermic machine perfusion improves the split-liver graft function in a large animal model.

METHODS

Porcine split-liver grafts were created by 75% liver resection. Hypothermic machine perfusion experimental groups were divided as follows: Group 1, perfusate, University of Wisconsin gluconate solution (UW group; n = 5), and Group 2, perfusate, histidine-tryptophan-ketoglutarate solution (HTK group; n = 4). After 4 h of preservation, the liver function was evaluated using an isolated liver reperfusion model for 2 h.

RESULTS

In the HTK group, the portal vein and hepatic artery resistance during hypothermic machine perfusion and the portal vein resistance during isolated liver reperfusion were lower than those in the UW group. In addition, the total Suzuki score for hepatic ischemia-reperfusion injury in the HTK group was significantly better than that in the UW group. The number of anti-ETS-related genes staining-positive sinusoid epithelial cell nuclei in the HTK group was higher than that in the UW group (not significant).

CONCLUSIONS

The histidine-tryptophan-ketoglutarate solution can be perfused with lower vascular resistance than the University of Wisconsin solution, reducing shear stress and preventing sinusoid epithelial cell injury in marginal grafts used as split-liver grafts.

A maternal high-fat diet induces fetal origins of NASH-HCC in mice

Maternal overnutrition affects offspring susceptibility to nonalcoholic steatohepatitis (NASH). Male offspring from high-fat diet (HFD)-fed dams developed a severe form of NASH, leading to highly vascular tumor formation. The cancer/testis antigen HORMA domain containing protein 1 (HORMAD1), one of 146 upregulated differentially expressed genes in fetal livers from HFD-fed dams, was overexpressed with hypoxia-inducible factor 1 alpha (HIF-1alpha) in hepatoblasts and in NASH-based hepatocellular carcinoma (HCC) in offspring from HFD-fed dams at 15 weeks old. Hypoxia substantially increased Hormad1 expression in primary mouse hepatocytes. Despite the presence of three putative hypoxia response elements within the mouse Hormad1 gene, the Hif-1alpha siRNA only slightly decreased hypoxia-induced Hormad1 mRNA expression. In contrast, N-acetylcysteine, but not rotenone, inhibited hypoxia-induced Hormad1 expression, indicating its dependency on nonmitochondrial reactive oxygen species production. Synchrotron-based phase-contrast micro-CT of the fetuses from HFD-fed dams showed significant enlargement of the liver accompanied by a consistent size of the umbilical vein, which may cause hypoxia in the fetal liver. Based on these findings, a maternal HFD induces fetal origins of NASH/HCC via hypoxia, and HORMAD1 is a potential therapeutic target for NASH/HCC.

Sorafenib-loaded silica-containing redox nanoparticles for oral anti-liver fibrosis therapy

Liver fibrosis is a chronic disease resulting from repetitive or prolonged liver injury with limited treatment options. Sorafenib has been reported to be a potential antifibrotic agent; however, its therapeutic effect is restricted because of its low bioavailability and severe adverse effects in the gastrointestinal (GI) tract. In this study, we developed sorafenib-loaded silica-containing redox nanoparticles (sora@siRNP) as an oral nanomedicine to treat liver fibrosis. The designed siRNP were prepared by self-assembly of amphiphilic block copolymers, which possess antioxidant nitroxide radicals as a side chain of the hydrophobic segment and porous silica particles in the nanoparticle core. The silica moieties in the core formed a crosslink between the self-assembling block copolymers to afford stable drug absorption, which could be useful in harsh GI conditions after oral drug administration. Based on in vitro evaluation, sora@siRNP exerted antiproliferative and antifibrotic effects against hepatic stellate cells (HSCs) and low toxicity against normal endothelial cells. A pharmacokinetic study showed that siRNP significantly improved the bioavailability and distribution of sorafenib in the liver. In an in vivo study using a mouse model of CCl₄-induced liver fibrosis, oral administration of sora@siRNP significantly suppressed the fibrotic area in comparison to free sorafenib administration. In mice with CCl₄-induced fibrosis, free sorafenib administration did not suppress the expression of α-smooth muscle actin; however, mice treated with sora@siRNP showed significantly suppressed expression of α-smooth muscle actin, indicating the inhibition of HSC activation, which was confirmed by in vitro experiments. Moreover, oral administration of free sorafenib induced severe intestinal damage and increased leakage into the gut, which can be attributed to the generation of reactive oxygen species (ROS). Our antioxidant nanocarriers, siRNP, reduced the adverse effects of local ROS scavenging in the GI tract. Our results suggest that sora@siRNP could serve as a promising oral nanomedicine for liver fibrosis.

Mutant GNAS limits tumor aggressiveness in established pancreatic cancer via antagonizing the KRAS-pathway

BACKGROUND

Mutations in GNAS drive pancreatic tumorigenesis and frequently occur in intraductal papillary mucinous neoplasm (IPMN); however, their value as a therapeutic target is yet to be determined. This study aimed at evaluating the involvement of mutant GNAS in tumor aggressiveness in established pancreatic cancer.

METHODS

CRISPR/Cas9-mediated GNAS R201H silencing was performed using human primary IPMN-associated pancreatic cancer cells. The role of oncogenic GNAS in tumor maintenance was evaluated by conducting cell culture and xenograft experiments, and western blotting and transcriptome analyses were performed to uncover GNAS-driven signatures.

RESULTS

Xenografts of GNAS wild-type cells were characterized by a higher Ki-67 labeling index relative to GNAS-mutant cells. Phenotypic alterations in the GNAS wild-type tumors resulted in a significant reduction in mucin production accompanied by solid with massive stromal components. Transcriptional profiling suggested an apparent conflict of mutant GNAS with KRAS signaling. A significantly higher Notch intercellular domain (NICD) was observed in the nuclear fraction of GNAS wild-type cells. Meanwhile, inhibition of protein kinase A (PKA) induced NICD in GNAS-mutant IPMN cells, suggesting that NOTCH signaling is negatively regulated by the GNAS-PKA pathway. GNAS wild-type cells were characterized by a significant invasive property relative to GNAS-mutant cells, which was mediated through the NOTCH regulatory pathway.

CONCLUSIONS

Oncogenic GNAS induces mucin production, not only via MUC2 but also via MUC5AC/B, which may enlarge cystic lesions in the pancreas. The mutation may also limit tumor aggressiveness by attenuating NOTCH signaling; therefore, such tumor-suppressing effects must be considered when therapeutically inhibiting the GNAS pathway.

Beneficial effects of end-ischemic oxygenated machine perfusion preservation for split-liver transplantation in recovering graft function and reducing ischemia-reperfusion injury

This study examined the efficacy of end-ischemic hypothermic oxygenated machine perfusion preservation (HOPE) using an originally developed machine perfusion system for split-liver transplantation. Porcine split-liver grafts were created via 75% liver resection after 10 min of warm ischemia. In Group 1, grafts were preserved by simple cold storage (CS) for 8 h (CS group; n = 4). In Group 2, grafts were preserved by simple CS for 6 h and end-ischemic HOPE for 2 h (HOPE group; n = 5). All grafts were evaluated using an isolated ex vivo reperfusion model with autologous blood for 2 h. Biochemical markers (aspartate aminotransferase and lactate dehydrogenase levels) were significantly better immediately after reperfusion in the HOPE group than in the CS group. Furthermore, the HOPE group had a better histological score. The levels of inflammatory cytokines (tumor necrosis factor-α, interferon-γ, interleukin-1β, and interleukin-10) were significantly lower after reperfusion in the HOPE group. Therefore, we concluded that end-ischemic HOPE for split-liver transplantation can aid in recovering the graft function and reducing ischemia-reperfusion injury. HOPE, using our originally developed machine perfusion system, is safe and can improve graft function while attenuating liver injury due to preservation.

No significant association between stable iodine intake and thyroid dysfunction in children after the Fukushima Nuclear Disaster: an observational study

PURPOSE

Stable iodine prophylaxis helps prevent childhood thyroid cancer in nuclear emergencies; however, there is limited information on its effect on thyroid function. This study aimed to examine thyroid function and autoimmunity among children and adolescents that took stable iodine after the Fukushima Nuclear Disaster.

METHODS

For this observational study, data were obtained from children and adolescents that underwent thyroid cancer screening at Hirata Central Hospital from April 2012 to March 2018. Participant characteristics, including possible hypothyroidism and hyperthyroidism, were compared between the prophylaxis and no-prophylaxis groups. Multivariable logistic regression models were used to assess for possible hypothyroidism, autoantibodies positive, and hyperthyroidism.

RESULTS

A total of 1,225 participants with stable iodine prophylaxis and 3,946 without prophylaxis were enrolled. Of those participants, blood samples were available for 144 and 1,201 participants in the prophylaxis and no-prophylaxis groups, respectively. There were 17 (11.8%) and 146 cases (12.2%) of possible hypothyroidism or autoantibodies positive cases in the prophylaxis and no-prophylaxis groups, respectively, and there were no cases and 3 cases (0.2%) of possible hyperthyroidism in those two groups, respectively. Multivariable analysis for possible hypothyroidism revealed no association between stable iodine intake and possible hypothyroidism or autoantibodies positive [odds ratio 0.716 (95% confidence interval 0.399-1.284)] (p = 0.262). We did not perform multivariable analysis for hyperthyroidism due to the limited number of cases.

CONCLUSION

Significant adverse effects of stable iodine intake on thyroid function were not observed among children and adolescents 7 years after the Fukushima Nuclear Disaster.

Generation of combined hepatocellular-cholangiocarcinoma through transdifferentiation and dedifferentiation in p53-knockout mice

The two principal histological types of primary liver cancers, hepatocellular carcinoma (HCC) and cholangiocarcinoma, can coexist within a tumor, comprising combined hepatocellular‐cholangiocarcinoma (cHCC‐CCA). Although the possible involvement of liver stem/progenitor cells has been proposed for the pathogenesis of cHCC‐CCA, the cells might originate from transformed hepatocytes that undergo ductular transdifferentiation or dedifferentiation. We previously demonstrated that concomitant introduction of mutant HRAS^V12 (HRAS) and Myc into mouse hepatocytes induced dedifferentiated tumors that expressed fetal/neonatal liver genes and proteins. Here, we examine whether the phenotype of HRAS‐ or HRAS/Myc‐induced tumors might be affected by the disruption of the Trp53 gene, which has been shown to induce biliary differentiation in mouse liver tumors. Hepatocyte‐derived liver tumors were induced in heterozygous and homozygous p53‐knockout (KO) mice by hydrodynamic tail vein injection of HRAS‐ or Myc‐containing transposon cassette plasmids, which were modified by deleting loxP sites, with a transposase‐expressing plasmid. The HRAS‐induced and HRAS/Myc‐induced tumors in the wild‐type mice demonstrated histological features of HCC, whereas the phenotype of the tumors generated in the p53‐KO mice was consistent with cHCC‐CCA. The expression of fetal/neonatal liver proteins, including delta‐like 1, was detected in the HRAS/Myc‐induced but not in the HRAS‐induced cHCC‐CCA tissues. The dedifferentiation in the HRAS/Myc‐induced tumors was more marked in the homozygous p53‐KO mice than in the heterozygous p53‐KO mice and was associated with activation of Myc and YAP and suppression of ERK phosphorylation. Our results suggest that the loss of p53 promotes ductular differentiation of hepatocyte‐derived tumor cells through either transdifferentiation or Myc‐mediated dedifferentiation.

Bacillus subtilis var. natto increases the resistance of Caenorhabditis elegans to gram-positive bacteria

AIMS

This study aimed to investigate the effect of Bacillus subtilis var. natto on the susceptibility of the model host, Caenorhabditis elegans, to bacterial infection.

METHODS AND RESULTS

Caenorhabditis elegans worms were fed with a standard food consisting of Escherichia coli OP50 strain (control) or B. subtilis (natto) during their larval stage. The worms were then infected with pathogenic bacteria. We analyzed their survival time and RNA sequencing-based transcriptome. Upon infection with Staphylococcus aureus and Enterococcus faecalis, the survival time of B. subtilis (natto)-fed worms was longer than that of the control. Transcriptome analyses showed upregulation of genes associated with innate immunity and defense response to gram-positive bacteria in B. subtilis (natto)-fed worms.

CONCLUSIONS

Bacillus subtilis (natto) conferred an increased resistance of C. elegans to gram-positive bacteria. Our findings provided insights into the molecular mechanisms underlying B. subtilis (natto)-regulated host immunity and emphasized its probiotic properties for preventing and alleviating infections caused by gram-positive bacteria.

SIGNIFICANCE AND IMPACT OF THE STUDY

To the best of our knowledge, this is the first study to show that B. subtilis (natto) confers specific resistance against gram-positive bacteria.

Decreased Portal Circulation Augments Fibrosis and Ductular Reaction in Nonalcoholic Fatty Liver Disease in Mice

Nonalcoholic fatty liver disease often progresses to cirrhosis and causes liver cancer, but mechanisms of its progression are yet to be elucidated. Although nonalcoholic fatty liver disease is often associated with abnormal portal circulation, there have not been any experimental studies to test its pathogenic role. Here, whether decreased portal circulation affected the pathology of nonalcoholic steatohepatitis (NASH) was examined using congenital portosystemic shunt (PSS) in C57BL/6J mice. Whereas PSS significantly attenuated free radical-mediated carbon tetrachloride injury, it augmented pericellular fibrosis in the centrilobular area induced by a 0.1% methionine choline-deficient l-amino acid-defined high-fat diet (CDAHFD). PSS aggravated ductular reaction and increased the expression of connective tissue growth factor. Pimonidazole immunohistochemistry of the liver revealed that the centrilobular area of PSS-harboring mice was more hypoxic than that of control mice. Although tissue hypoxia was observed in the fibrotic area in CDAHFD-induced NASH in both control and PSS-harboring mice, it was more profound in the latter, which was associated with higher carbonic anhydrase 9 and vascular endothelial growth factor expression and neovascularization in the fibrotic area. Furthermore, partial ligation of the portal vein also augmented pericellular fibrosis and ductular reaction induced by a CDAHFD. These results demonstrate that decreased portal circulation, which induces hypoxia due to disrupted intralobular perfusion, is an important aggravating factor of liver fibrosis in NASH.

Hepatocyte Mitogen-Activated Protein Kinase Kinase 7 Contributes to Restoration of the Liver Parenchyma Following Injury in Mice

BACKGROUND AND AIMS

Mitogen-activated protein kinase kinase (MKK) 7 and MKK4 are upstream activators of c-Jun NH₂ -terminal kinases (JNKs) and have been shown to be required for the early development of the liver. Although it has been suggested that MKK7 might be involved in the regulation of hepatocyte proliferation, the functional role of MKK7 in the liver has remained unclear.

APPROACH AND RESULTS

Here, we examined phenotypic alterations in liver-specific or hepatocyte/hematopoietic cell-specific MKK7 knockout (KO) mice, which were generated by crossing MKK7^LoxP/LoxP with albumin-cyclization recombination (Alb-Cre) or myxovirus resistance protein 1-Cre mice, respectively. The livers of Alb-Cre^-/+ MKK7^LoxP/LoxP mice developed without discernible tissue disorganization. MKK7 KO mice responded normally to liver injuries incurred by partial hepatectomy or injection of CCl₄ . However, tissue repair following CCl₄ -induced injury was delayed in MKK7 KO mice compared with that of control mice. Furthermore, after repeated injections of CCl₄ for 8 weeks, the liver in MKK7 KO mice showed intense fibrosis with increased protractive hepatocyte proliferation, suggesting that MKK7 deficiency might affect regenerative responses of hepatocytes in the altered tissue microenvironment. MKK7 KO hepatocytes demonstrated normal proliferative activity when cultured in monolayers. However, MKK7 KO significantly suppressed branching morphogenesis of hepatocyte aggregates within a collagen gel matrix. Microarray analyses revealed that suppression of branching morphogenesis in MKK7 KO hepatocytes was associated with a reduction in mRNA expression of transgelin, glioma pathogenesis related 2, and plasminogen activator urokinase-type (Plau); and forced expression of these genes in MKK7 KO hepatocytes partially recovered the attenuated morphogenesis. Furthermore, hepatocyte-specific overexpression of Plau rescued the impaired tissue repair of MKK7 KO mice following CCl₄ -induced injury.

CONCLUSIONS

MKK7 is dispensable for the regenerative proliferation of hepatocytes but plays important roles in repair processes following parenchymal destruction, possibly through modulation of hepatocyte-extracellular matrix interactions.

Construction of a recombinant vaccinia virus expressing Babesia gibsoni thrombospondin-related anonymous protein and evaluation of its immunogenicity in mice

Previously, we have identified a gene encoding thrombospondin-related anonymous protein of Babesia gibsoni (BgTRAP), and have shown that the antisera raised against recombinant BgTRAP expressed in Escherichia coli inhibited the growth of parasites. In the present study, a recombinant vaccinia virus expressing the BgTRAP (VV/BgTRAP) was constructed. A specific band with a molecular mass of 80 kDa, which is similar to that of native BgTRAP on the merozoites of B. gibsoni, was detected in the supernatant of VV/ BgTRAP-infected RK13 cells. Mice inoculated with VV/BgTRAP produced a specific antiBgTRAP response. The antiserum against VV/BgTRAP showed reactivity against the native BgTRAP on parasites. These results indicated that the recombinant vaccinia virus expressing BgTRAP might be a vaccine candidate against canine B. gibsoni infection.

A Novel Preservation Solution Containing Quercetin and Sucrose for Porcine Kidney Transplantation

In organ transplantation, the University of Wisconsin (UW) solution has been the gold standard for organ preservation. Quercetin (Que) has numerous antioxidant and anti-inflammatory activities, and sucrose (Suc) may be effective for cold storage (CS). This study aimed to investigate the in vitro protective effect of Que and Suc on cold injury to the kidney and to determine whether Que + Suc could improve ischemia-reperfusion injury during CS and hypothermic oxygenated perfusion (HOPE) in autologous transplantation models.

METHODS

BHK-21 cells were stored at 4°C for 3 days in UW solution for CS/machine perfusion (CS/MP-UW) with Que (33.1 μM, 3.3 μM, 0.33 μM) and Suc (0.1 M). In a porcine model of renal autologous transplantation, left kidney grafts were preserved under 3 conditions: group 1, CS preservation for 24 hours; group 2, CS preservation for 22 hours and HOPE with CS/MP-UW solution for 2 hours; and group 3, identical preservation as group 2, with Que and Suc added to the solution. Animals were euthanized on day 7 after autologous transplantation.

RESULTS

After 3 days of CS preservation, the CS/MP-UW solution with Que (33.1 μM, 3.3 μM) and Suc showed significant cell protection against cold injury. In the porcine model of renal autologous transplantation, the last blood Cre level and the blood lipid hydroperoxide on posttransplantation day 2 were significantly different between group 1 and group 3. Moreover, the total endothelial, glomerular, tubular, interstitial (EGTI) histology score in the kidney tissue was also significantly different. Regarding the change in renal resistance in HOPE, the decrease observed in group 3 was significantly larger than that in group 2.

CONCLUSIONS

Our results suggest that the addition of Que and Suc to a UW solution can improve kidney preservation and could potentially enhance the outcome of kidney transplantation.

Low bone mineral density due to secondary hyperparathyroidism in the GlatmTg(CAG-A4GALT) mouse model of Fabry disease

Low bone mineral density (BMD)—diagnosed as osteoporosis or osteopenia—has been reported as a new characteristic feature of Fabry disease; however, the mechanism underlying the development of low BMD is unknown. We previously revealed that a mouse model of Fabry disease [Gla^tmTg(CAG‐A4GALT)] exhibits impaired functioning of medullary thick ascending limb (mTAL), leading to insufficient Ca²⁺ reabsorption and hypercalciuria. Here, we investigated bone metabolism in Gla^tmTg(CAG‐A4GALT) mice without marked glomerular or proximal tubular damage. Low BMD was detected by 20 weeks of age via micro‐X‐ray‐computed tomography. Bone histomorphometry revealed that low BMD results by accelerated bone resorption and osteomalacia. Plasma parathyroid hormone levels increased in response to low blood Ca²⁺—not plasma fibroblast growth factor 23 (FGF‐23) elevation—by 5 weeks of age and showed progressively increased phosphaturic action. Secondary hyperparathyroidism developed by 20 weeks of age and caused hyperphosphatemia, which increased plasma FGF‐23 levels with phosphaturic action. The expression of 1α‐hydroxylase [synthesis of 1α,25(OH)₂D₃] in the kidney did not decrease, but that of 24‐hydroxylase [degradation of 1α,25(OH)₂D₃] decreased. Vitamin D deficiency was ruled out as the cause of osteomalacia, as plasma 1α,25(OH)₂D₃ and 25(OH)D₃ levels were maintained. Results demonstrate that secondary hyperparathyroidism due to mTAL impairment causes accelerated bone resorption and osteomalacia due to hyperphosphaturia and hypercalciuria, leading to low BMD in Fabry model mice.

Left ventricular outflow tract pressure gradient changes after carvedilol-disopyramide cotherapy in a cat with hypertrophic obstructive cardiomyopathy

Disopyramide reduces the left ventricular outflow tract (LVOT) pressure gradient and improves symptoms in humans with hypertrophic obstructive cardiomyopathy (HOCM). However, the efficacy of disopyramide in cats has not been reported. We treated a cat with HOCM with carvedilol and disopyramide cotherapy and monitored the changes in LVOT flow velocity and N-terminal pro B-type natriuretic peptide (NT-proBNP) concentration. A 10-month-old neutered male Norwegian Forest cat was referred with a moderate systolic cardiac murmur. Echocardiography revealed thickening of the left ventricular wall, systolic anterior motion of the mitral valve leaflets, and turbulent aortic flow in the LVOT at systole. The LVOT flow velocity was 5.6 m/s. The plasma NT-proBNP concentration exceeded 1,500 pmol/L. The cat was diagnosed with HOCM and the β-blocker carvedilol was started and gradually increased to 0.30 mg/kg, bid. After 57 days, the LVOT flow velocity (4.8 m/s) and plasma NT-proBNP concentration (870 pmol/L) had decreased but remained elevated. Therefore, disopyramide was added at 5.4 mg/kg po bid and increased to 10.9 mg/kg po bid after 22 days. After 141 days of carvedilol and disopyramide treatment, the systolic anterior motion of the mitral valve leaflets had disappeared and the LVOT flow velocity and plasma NT-proBNP concentration had decreased to 0.7 m/s and 499 pmol/L, respectively. No adverse effect has been observed during the follow-up. Disopyramide might relieve feline LVOT obstruction after only partial response to a beta-blocker. Further large-scale studies are required to investigate the efficacy and safety of disopyramide use in cats with moderate to severe HOCM.

Applicability of Hypothermic Oxygenate Machine Perfusion Preservation for Split-Liver Transplantation in a Porcine Model: An Experimental Study

Background

Split-liver transplantation can be useful in situations of limited donor resources. However, novel preservation methods are required to help the recipient recover from severe ischemic reperfusion injury incurred due to receiving a relatively small liver graft.

Material/Methods

Our experiment was performed using porcine livers without warm ischemia time, assuming a brain-dead organ. We made porcine split-liver grafts by 75% liver resection at the back table and divided the specimens into 4 groups. Group 1 was preserved with simple cold storage after splitting (CS; n=3), Group 2 was preserved with hypothermic perfusion preservation (HMP) after splitting (SBP; n=3), Group 3 was preserved with HMP after splitting under perfusion preservation (SDP; n=4), and Group 4 had the whole liver perfused as control grafts (Whole Liver; n=3). To assess potential methods of preservation and their effects, all grafts were evaluated by an ex vivo isolated liver reperfusion model using diluted autologous blood.

Results

Portal vein pressure resistances during reperfusion were low in Group3 (SDP). Hepatic artery pressure resistances during reperfusion were markedly higher in Group 1(CS) than in the other groups. The levels of AST and LDH were high and increased at 2 h after reperfusion in Group 1 (CS). The histological findings show that the liver cell structure was irregular in Group 1 (CS) but remained regular in Groups 2 (SBP) and 3 (SDP). Histological Suzuki scores were also significantly better in Groups 2 (SBP) and 3 (SDP) compared with Group 1 (CS).

Conclusions

Splitting the liver under machine perfusion preservation may help restore the function and reduce ischemia-reperfusion injury.

Impact of human-derived hemoglobin based oxygen vesicles as a machine perfusion solution for liver donation after cardiac death in a pig model

The recent clinical application of perfusion technology for the machine preservation of donation after cardiac death (DCD) grafts has some advantages. Oxygenation has been proposed for the preservation of DCD liver grafts. The aim of this study is to clarify whether the use of HbV-containing preservation solution during the subnormothermic machine perfusion (SNMP) of the liver graft improves the graft function of DCD porcine livers in an ex vivo reperfusion model. Pig livers were excised after 60 minutes of warm ischemic time and were preserved under one of three preservation conditions for 4 hours. The preservation conditions were as follows: 4°C cold storage (CS group; N = 5), Hypothermic machine preservation (HMP) with UW gluconate solution (HMP group; N = 5), SNMP (21°C) with UW gluconate solution (SNMP group; N = 5), SNMP (21°C) with HbVs (Hb; 1.8 mg/dl) perfusate (SNMP+HbV group; N = 5). Autologous blood perfusion was performed for 2 hours in an isolated liver reperfusion model (IRM). The oxygen consumption of the SNMP and SNMP+HbV group was higher than the HMP groups (p < 0.05). During the reperfusion, the AST level in the SNMP+HbV group was lower than that in the CS, HMP and SNMP groups. The changes in pH after reperfusion was significantly lower in SNMP+HbV group than CS and HMP groups. The ultrastructural findings indicated that the mitochondria of the SNMP+HbV group was well maintained in comparison to the CS, HMP and SNMP groups. The SNMP+HbVs preservation solution protected against metabolic acidosis and preserved the liver function after reperfusion injury in the DCD liver.

Impact of Machine Perfusion on Sinusoid Microcirculation of Liver Graft Donated After Cardiac Death

BACKGROUND

The present study examined the impact of oxygenated machine perfusion on preservation of liver grafts donated after cardiac death by measuring sinusoidal endothelial injury and microcirculatory disturbances.

MATERIALS AND METHODS

Fifteen porcine livers were retrieved 60 min after warm ischemia and allocated into three groups as follows: (1) CS group: static cold storage, (2) HMP group: oxygenated hypothermic perfusion preservation, (3) SNMP group: oxygenated subnormothermic perfusion preservation. The liver grafts donated after cardiac death were preserved for 4 h in different treatment conditions mentioned previously, then subject to ex vivo reperfusion for 2 h using diluted allogeneic blood. The hemodynamic parameters, liver function tests, tissue adenosine triphosphate (ATP) levels, and immunohistochemical findings were investigated.

RESULTS

The number of sinusoidal epithelial cells and trabecular structures were maintained after 4 h of preservation in the CS, HMP, and SNMP group. Liver tissue ATP levels after 4 h of preservation in the HMP and SNMP groups were significantly higher compared with that in the CS group. The sinusoidal epithelial cells were significantly exfoliated to a more severe extent in the CS group than in the HMP and SNMP groups. Intrasinusoidal platelet aggregation occurred more frequently in the CS group than in the HMP and SNMP groups.

CONCLUSIONS

The results indicated that oxygenated machine perfusion preservation was important to prevent the depletion of tissue ATP and maintain sinusoidal homeostasis regardless of the perfusate temperature. Our findings suggest oxygenated machine perfusion preservation as an effective alternative to static cold storage.

Successful Treatment of Nivolumab-related Cholangitis with Prednisolone: A Case Report and Review of the Literature

The patient was a 76-year-old man who was treated with nivolumab due to recurrent gastric cancer. A blood examination revealed grade 3 alkaline phosphatase (ALP) elevation. A histopathological examination revealed marked portal infiltration, including eosinophils and CD4+ and CD8+ T lymphocytes, suggesting nivolumab-related cholangitis accompanied by the features of both an immune-related adverse event (irAE) and drug-induced liver injury (DILI) with allergic reaction. The patient's ALP level immediately decreased after the administration of prednisolone. Although nivolumab-related cholangitis, a rare irAE, has been reported to be refractory to steroid therapy, patients with features of irAE and allergic DILI might immediately respond to prednisolone.

Emergence of the Dedifferentiated Phenotype in Hepatocyte-Derived Tumors in Mice: Roles of Oncogene-Induced Epigenetic Alterations

Hepatocellular carcinoma often reactivates the genes that are transiently expressed in fetal or neonatal livers. However, the mechanism of their activation has not been elucidated. To explore how oncogenic signaling pathways could be involved in the process, we examined the expression of fetal/neonatal genes in liver tumors induced by the introduction of myristoylated v‐akt murine thymoma viral oncogene (AKT), HRas proto‐oncogene, guanosine triphosphatase (HRAS^V12), and MYC proto‐oncogene, bHLH transcription factor (Myc), in various combinations, into mouse hepatocytes in vivo. Distinct sets of fetal/neonatal genes were activated in HRAS‐ and HRAS/Myc‐induced tumors: aldo‐keto reductase family 1, member C18 (Akr1c18), glypican 3 (Gpc3), carboxypeptidase E (Cpe), adenosine triphosphate‐binding cassette, subfamily D, member 2 (Abcd2), and trefoil factor 3 (Tff3) in the former; insulin‐like growth factor 2 messenger RNA binding protein 3 (Igf2bp3), alpha fetoprotein (Afp), Igf2, and H19, imprinted maternally expressed transcript (H19) in the latter. Interestingly, HRAS/Myc‐induced tumors comprised small cells with a high nuclear/cytoplasmic ratio and messenger RNA (mRNA) expression of delta‐like noncanonical Notch ligand 1 (Dlk1), Nanog homeobox (Nanog), and sex determining region Y‐box 2 (Sox2). Both HRAS‐ and HRAS/Myc‐induced tumors showed decreased DNA methylation levels of Line1 and Igf2 differentially methylated region 1 and increased nuclear accumulation of 5‐hydroxymethylcytosine, suggesting a state of global DNA hypomethylation. HRAS/Myc‐induced tumors were characterized by an increase in the mRNA expression of enzymes involved in DNA methylation (DNA methyltransferase [Dnmt1, Dnmt3]) and demethylation (ten‐eleven‐translocation methylcytosine dioxygenase 1 [Tet1]), sharing similarities with the fetal liver. Although mouse hepatocytes could be transformed by the introduction of HRAS/Myc in vitro, they did not express fetal/neonatal genes and sustained global DNA methylation, suggesting that the epigenetic alterations were influenced by the in vivo microenvironment. Immunohistochemical analyses demonstrated that human hepatocellular carcinoma cases with nuclear MYC expression were more frequently positive for AFP, IGF2, and DLK1 compared with MYC‐negative tumors. Conclusion: The HRAS signaling pathway and its interactions with the Myc pathway appear to reactivate fetal/neonatal gene expression in hepatocytic tumors partly through epigenetic alterations, which are dependent on the tumor microenvironment.

Serological diversity, molecular characterisation and antimicrobial sensitivity of avian pathogenic Escherichia coli (APEC) isolates from broiler chickens in Kashmir, India

The present study has determined the serological diversity, virulence-gene profile and in vitro antibiogram of avian pathogenic Escherichia coli (APEC) isolates from broiler chickens in India suspected to have died of colibacillosis. The virulence-gene profile of APEC was compared with that of the Escherichia coli isolates from faeces of apparently healthy chickens, called avian faecal E. coli (AFEC). In total, 90 representative isolates of APEC and 63 isolates of AFEC were investigated in the present study. The APEC were typed into 19 serogroups, while some isolates were rough and could not be typed. Most prevalent serogroup was O2 (24.44%). Among the eight virulence genes studied, the prevalence of seven genes (iss, iucD, tsh, cva/cvi, irp2, papC and vat) was significantly higher in APEC than in AFEC isolates. However, there was no significant difference between APEC and AFEC isolates for possession of astA gene. The most frequent gene detected among the two groups of organisms was iss, which was present in 98.88% and 44.44% of APEC and AFEC isolates respectively. The in vitro antibiogram showed that the majority (96.6%) of APEC isolates were resistant to tetracycline, while 82.2% were resistant to cephalexin, 78.8% to cotrimoxazole, 68.8% to streptomycin and 63.3% to ampicillin. However, most of them (84.45%) were sensitive to gentamicin. Thus, it is concluded that APEC from the broiler chickens carried putative virulence genes that attributed to their pathogenicity. Furthermore, the majority of APEC isolates were found to be multi-drug resistant, which, in addition to leading treatment failures in poultry, poses a public health threat.

Mouse Model for Hepatocellular Carcinoma and Cholangiocarcinoma Originated from Mature Hepatocytes

Liver cancer consists of two main histological subtypes, hepatocellular carcinoma and cholangiocarcinoma, both of which have poor prognosis. Therefore, in searching for new therapeutic targets, adequate mouse models to develop and validate therapeutic strategies are urgently needed. Although there are mouse models of liver cancer, each model has shortcomings. To overcome these shortcomings, a mouse model using a hydrodynamic tail vein injection and the Sleeping Beauty transposon was developed. By inducing stable expression of oncogenes in mouse hepatocytes in vivo, the model can easily induce liver cancer with specific characteristics that depend on the oncogenes used to induce carcinogenesis. Here, we describe the details of the methods to induce hepatocellular carcinoma or cholangiocarcinoma from mouse hepatocytes.

Evaluation Using an Isolated Reperfusion Model for Porcine Liver Donated After Cardiac Death Preserved with Oxygenated Hypothermic Machine Perfusion

BACKGROUND Machine perfusion techniques offer a solution to the serious organ shortage. However, to assess the effects of machine perfusion, many detailed studies are required. In this study, an ex vivo reperfusion model using diluted autologous blood was confirmed to evaluate the utility of machine preservation for livers donated after cardiac death (DCD). In particular, beneficial effects of the oxygenated hypothermic machine perfusion (HMP) for DCD porcine livers are evaluated. MATERIAL AND METHODS Porcine livers were procured under warm ischemia time (WIT) of 60 min. The livers were preserved by hypothermic machine perfusion (HMP) or static cold storage (CS) for 4 h. After the preservation, the livers were perfused for 2 h using the ex vivo reperfusion model with diluted blood oxygenated by a membrane oxygenator at 35-38°C. RESULTS At 2 h of ex vivo reperfusion with 60 min of warm ischemic time (WIT), the portal vein pressure for CS was higher than HMP (18.8±15.9 vs. 7.5±3.9 [mmHg] in 60 min). Furthermore, LDH in CS was higher than HMP (528.5±149.8 vs. 194.1±32.2 [IU/L/100 g liver] in 60 min. P<0.05). Lactate after CS (60) was significantly higher than HMP (60) (8.67±0.39 vs. 5.68±0.60 [mmol/L] at 60 min. p<0.01). CONCLUSIONS The ex vivo reperfusion model can be used to evaluate the utility of machine perfusion. Advantages of HMP for DCD livers are evaluated with this model.

Cerebral cystic echinococcosis in Mongolian children caused by Echinococcus canadensis

Recent molecular re-evaluation of Echinococcus granulosus, which causes cystic echinococcosis (CE), has revealed that it is not a single species, but instead consists of 5 cryptic species. Among them, E. granulosus (dog-sheep strain) is predominant (75%) followed by Echinococcus canadensis (22%). The major affected organs, in humans, are the liver (88%) and lungs (11%). Primary cerebral CE comprises less than 1% of all cases. As cerebral CE cases are rare, there are few reports with molecular confirmation of the causative species. This study reports mitochondrial gene analysis from 4 Mongolian pediatric cerebral CE cases. Molecular confirmation was obtained for 3 of the 4 cases, with all 3 cases determined to be due to E. canadensis (G6/G7) infection. None of the cases had other organ involvement. This is only the third report on the molecular identification of the Echinococcus species responsible for cerebral CE, and only the second report of E. canadensis (G6/G7) being the causative agent of cerebral CE.

Medullary thick ascending limb impairment in the GlatmTg(CAG-A4GALT) Fabry model mice

A main feature of Fabry disease is nephropathy, with polyuria an early manifestation; however, the mechanism that underlies polyuria and affected tubules is unknown. To increase globotriaosylceramide (Gb3) levels, we previously crossbred asymptomatic Gla^tm mice with transgenic mice that expressed human Gb3 synthase (A4GALT) and generated the Gla^tmTg(CAG-A4GALT) symptomatic Fabry model mice. Additional analyses revealed that these mice exhibit polyuria and renal dysfunction without remarkable glomerular damage. In the present study, we investigated the mechanism of polyuria and renal dysfunction in these mice. Gb3 accumulation was mostly detected in the medulla; medullary thick ascending limbs (mTALs) were the most vacuolated tubules. mTAL cells contained lamellar bodies and had lost their characteristic structure (i.e., extensive infolding and numerous elongated mitochondria). Decreased expression of the major molecules—Na⁺-K⁺-ATPase, uromodulin, and Na⁺-K⁺-2Cl⁻ cotransporter—that are involved in Na⁺ reabsorption in mTALs and the associated loss of urine-concentrating ability resulted in progressive water- and salt-loss phenotypes. Gla^tmTg(CAG-A4GALT) mice exhibited fibrosis around mTALs and renal dysfunction. These and other features were consistent with pathologic findings in patients with Fabry disease. Results demonstrate that mTAL dysfunction causes polyuria and renal impairment and contributes to the pathophysiology of Fabry nephropathy.—Maruyama, H., Taguchi, A., Nishikawa, Y., Guili, C., Mikame, M., Nameta, M., Yamaguchi, Y., Ueno, M., Imai, N., Ito, Y., Nakagawa, T., Narita, I., Ishii, S. Medullary thick ascending limb impairment in the Gla^tmTg(CAG-A4GALT) Fabry model mice.

Usefulness of ultra-high resolution mapping for detecting epicardial atrial activation during mitral isthmus ablation

We describe a patient with perimitral atrial flutter (PMF) following the atrial fibrillation ablation and the linear ablation at the mitral isthmus (MI). From both the activation and the voltage maps using ultra-high resolution mapping, we detected the epicardial connection through the coronary sinus (CS) within the entire reentrant circuit. Point ablation within the CS, not additional linear MI ablation from the endocardium terminates PMF, with a bidirectional block across the low voltage area at the MI.

The ultrastructural characteristics of porcine hepatocytes donated after cardiac death and preserved with warm machine perfusion preservation

The effects of warm machine perfusion preservation of liver grafts donated after cardiac death on the intracellular three-dimensional ultrastructure of the organelles in hepatocytes remain unclear. Here we analyzed comparatively the ultrastructure of the endomembrane systems in porcine hepatocytes under warm ischemia and successive hypothermic and midthermic machine perfusion preservation, a type of the warm machine perfusion. Porcine liver grafts which had a warm ischemia time of 60 minutes were perfused for 4 hours with modified University of Wisconsin gluconate solution. Group A grafts were preserved with hypothermic machine perfusion preservation at 8°C constantly for 4 hours. Group B grafts were preserved with rewarming up to 22°C by warm machine perfusion preservation for 4 hours. An analysis of hepatocytes after 60 minutes of warm ischemia by scanning electron microscope revealed the appearance of abnormal vacuoles and invagination of mitochondria. In the hepatocytes preserved by subsequent hypothermic machine perfusion preservation, strongly swollen mitochondria were observed. In contrast, the warm machine perfusion preservation could preserve the functional appearance of mitochondria in hepatocytes. Furthermore, abundant vacuoles and membranous structures sequestrating cellular organelles like autophagic vacuoles were frequently observed in hepatocytes after warm machine perfusion preservation. In conclusion, the ultrastructure of the endomembrane systems in the hepatocytes of liver grafts changed in accordance with the temperature conditions of machine perfusion preservation. In addition, temperature condition of the machine perfusion preservation may also affect the condition of the hepatic graft attributed to autophagy systems, and consequently alleviate the damage of the hepatocytes.

Oncogenic Determination of a Broad Spectrum of Phenotypes of Hepatocyte-Derived Mouse Liver Tumors

Activation of the phosphoinositide 3-kinase-AKT, Yes-associated protein (YAP), and MYC pathways is involved in human liver cancers, including hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC). However, the nature of the interactions among these pathways has remained poorly understood. Herein, we demonstrate the coordination of these pathways during the formation of mouse liver tumors induced by hepatocyte-specific somatic integration of myristoylated AKT, mutant YAP, Myc, or their combinations. Although the introduction of YAP or Myc alone was inefficient in inducing tumors, these proteins accelerated tumorigenesis induced by AKT. The generated tumors demonstrated various histological features: low-grade HCC by AKT/Myc, CC by AKT/YAP, and high-grade HCC by AKT/Myc/YAP. CC induced by AKT/YAP was associated with activation of the Notch pathway. Interestingly, the combination of Myc and YAP generated tumors composed of hepatoblast/stem-like cells expressing mRNA for Afp, Dlk1, Nanog, and Sox2 and occasionally forming immature ducts. Finally, immunohistochemical analysis revealed that human HCC and CC were predominantly associated with phosphorylation of S6 and glycogen synthase kinase-3β, respectively, and >60% of CC cases were positive for both phosphorylated glycogen synthase kinase--3β and YAP. Our study suggests that hepatocyte-derived tumors demonstrate a wide spectrum of tumor phenotypes, including HCC, CC, and hepatoblastoma-like, through the combinatory effects of the oncogenic pathways and that the state of the phosphoinositide 3-kinase-AKT pathway is a key determinant of differentiation.