No impact of donor sex on the recurrence of hepatocellular carcinoma after liver transplantation.

BACKGROUND/PURPOSE: We aimed to verify a recent theory that female donors reduced the risk of hepatocellular carcinoma (HCC) recurrence after liver transplantation (LT). METHODS: A total of 1118 recipients registered in the Japanese Liver Transplantation Society database were evaluated for HCC, of whom 446 received a graft from female donors (F-D group) and 672 from male donors (M-D group). RESULTS: Between the groups, donor age, recipient age and sex, positivity of hepatitis viruses, and graft type were different, whereas tumor-related factors were all comparable. The 5-year overall recurrence rates were 14% and 16% in the F-D and M-D groups, respectively (P = 0.59). The 5-year graft recurrence rate was also comparable between the groups (4% and 6%, respectively, P = 0.17). Neither univariate nor multivariate analysis identified donor sex as a significant risk factor for recurrence. Propensity score matching showed similar 5-year overall recurrence rates (15% in the F-D group and 14% in the M-D group, P = 0.63) and graft recurrence rates (5% and 5%, respectively, P = 0.94) between the groups. CONCLUSION: Donor sex did not affect post-LT recurrence of HCC in the Japanese cohort and should not be considered in the process of donor selection or organ allocation.

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-1ß, 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.

Severe liver injury with traumatic cardiac arrest successfully treated by damage control surgery and transcatheter arterial embolization in the hybrid operating room: a case report.

BACKGROUND: The damage control approach is known to reduce the mortality rate in severely injured patients and has now become a common practice. Transcatheter arterial embolization (TAE) has been shown to be useful with combining with damage control laparotomy in identifying and controlling active arterial hemorrhage. Hybrid operating room (OR) allows both damaged control surgery and TAE in the same location in minimal time. We report a case of a patient with three cardiac arrests who was saved by early intervention using damage control surgery (DCS) with interventional radiology (IVR) in the hybrid OR. CASE PRESENTATION: A 46-year-old woman was injured in a collision with a tree while snowboarding. She was eventually transported to hybrid operating room in our hospital with the diagnosis of significant liver laceration and hemorrhagic shock. Damage control surgery was performed with perihepatic packing (PHP) and TAE was conducted to stop active bleeding from right hepatic artery. She experienced 3 times of cardiopulmonary arrest, which was successfully resuscitated on each occasion. Although she had total of 3 times of laparotomy but tolerated well. She was discharged on day 82 of hospitalization and showed no neurological sequelae. CONCLUSION: Saving the life of a patient with severe trauma requires a multidisciplinary approach with cooperation and early information sharing among trauma team members. Sharing treatment strategy with the trauma team and early intervention using DCS with IVR in the hybrid operating room could save the patient's life.

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.

Incidental intrahepatic cholangiocarcinoma in patients undergoing liver transplantation: A multi-center study in Japan.

BACKGROUND: Intrahepatic cholangiocarcinoma had been considered a contraindication for liver transplantation because of poorer outcomes. However, incidental intrahepatic cholangiocarcinoma in the explanted liver has been reported because of the difficulty of obtaining an accurate diagnosis in cirrhotic livers on preoperative imaging. METHODS: We conducted a nationwide survey to analyze the incidence of incidental intrahepatic cholangiocarcinoma and outcomes after liver transplantation, in Japan. RESULTS: Forty-five of 64 institutions (70%) responded to our initial investigation. Between January 2001 and December 2015, 6627 liver transplantations were performed in these 45 institutions, with 19 cases (0.3%) of incidental intrahepatic cholangiocarcinoma reported from 12 transplant centers. Six cases were diagnosed as hepatocellular carcinoma preoperatively. The 1-, 3-, and 5-year recurrence-free survival rates were 79%, 45%, and 45%, respectively. Tumor recurrence after liver transplantation was found in 10 patients (53%). The 1-, 3-, and 5-year overall survival rates were 79%, 63%, and 46%, respectively. CONCLUSIONS: Intrahepatic cholangiocarcinoma at liver transplantation is associated with a high risk of recurrence and poor prognosis, even these tumors are detected incidentally in the explanted liver.

A comparison of laparoscopic procedures performed by novice medical students using 8K ultra-high-definition/two-dimensional and 2K high-definition/three-dimensional monitors.

PURPOSE: 8K Ultra-high-definition (UHD) imaging has been developed in accordance with the progression of imaging technologies. We evaluated laparoscopic procedures performed by novice medical students using 2K/two-dimensional (2D), 2K/three-dimensional (3D) and 8K/2D monitors, with a particular focus on depth perception. METHODS: Nine medical students were enrolled. They performed two tasks using 2K/2D, 2K/3D and 8K/2D monitors. In Task 1, they were asked to grasp three metal rods with forceps using each hand. In Task 2, they were asked to grasp a metal rod with forceps held in the right hand, pass the metal rod through a metal ring and transfer it to their left hand. RESULTS: In Task 1, when performed with the dominant hand, the procedures performed using 2K/3D took a significantly shorter time than those performed using 8K/2D (P = 0.04). However, there was no significant difference among the three groups in the time required for procedures performed by the non-dominant hand. In Task 2, the procedure time with 2K/2D was significantly longer than that with 2K/3D or 8K/2D (P = 0.02). CONCLUSION: 2K/3D showed superior utility to 8K/2D for performing forceps procedures using the dominant hand. However, when the movement of both hands was coordinated ("bi-hand coordination"), the laparoscopic procedures were performed almost as deftly with 8K/2D and 2K/3D.

Rapid Detection of Microbial Contamination in Intravenous Fluids by ATP-Based Monitoring System.

In this study, we investigated four clinical cases of microbial contamination of in-use intravenous infusion fluid, detected by measuring "Adenosine triphosphate (ATP) + adenosine monophosphate (AMP)" ("ATP+AMP") levels. High "ATP+AMP" values correlate with microbial contamination, and by utilizing these values as indicator for microbial contamination possibility, we were able to rapidly detect the contamination and recommend replacement of catheters and administration sets. In three out of four cases, changing the infusion fluid led to improvement in the condition of the patients. "ATP+AMP" levels can be used to confirm microbial contamination of in-use intravenous infusion fluids, as it is fast (several minites) and convenient to measure them.

Phosphorylated vimentin as an immunotherapeutic target against metastatic colorectal cancer.

Colorectal cancer (CRC) patients with metastatic lesions have low 5-year survival rates. During metastasis, cancer cells often obtain unique characteristics such as epithelial-mesenchymal transition (EMT). Vimentin a biomarker contributes to EMT by changing cell shape and motility. Since abnormal phosphorylation is a hallmark of malignancy, targeting phosphorylated vimentin is a feasible approach for the treatment of metastatic tumors while sparing non-tumor cells. Recent evidence has revealed that both CD8 cytotoxic T lymphocytes (CTLs) and also CD4 helper T lymphocytes (HTLs) can distinguish post-translationally modified antigens from normal antigens. Here, we showed that the expression of phosphorylated vimentin was upregulated in metastatic sites of CRC. We also showed that a chemotherapeutic reagent augmented the expression of phosphorylated vimentin. The novel phosphorylated helper peptide epitopes from vimentin could elicit a sufficient T cell response. Notably, precursor lymphocytes that specifically reacted to these phosphorylated vimentin-derived peptides were detected in CRC patients. These results suggest that immunotherapy targeting phosphorylated vimentin could be promising for metastatic CRC patients.

Successful hepatic resection for recurrent hepatocellular carcinoma after lenvatinib treatment: A case report.

BACKGROUND: Lenvatinib has been shown to be noninferior to sorafenib regarding prognosis and recurrence rate in patients with unresectable hepatocellular carcinoma (HCC) who have not received prior systemic chemotherapy. In patients treated with lenvatinib, 40% of cases achieved sufficient tumor reduction to make potential surgery possible. However, the outcomes of such surgery are unknown. We report a successful case of hepatic resection for recurrent HCC after lenvatinib treatment. CASE SUMMARY: A 69-year-old man underwent right anterior sectionectomy for HCC in segment 8 of the liver. Ten months later, he was found to have an intrahepatic HCC recurrence that grew rapidly to 10 cm in diameter with sternal bone metastases. After confirming partial response to lenvatinib administration for 2 mo, a second hepatectomy was performed. Pathological examination showed that 80% of the tumor was necrotic. The patient did not develop any adverse effects under lenvatinib treatment. He was discharged at 25 d after surgery. Radiation therapy for bone metastases continued to be given under lenvatinib, and the patient has remained alive for 1 year after the second hepatectomy. CONCLUSION: The prognosis of patients with recurrent HCC may be improved by liver resection combined with prior lenvatinib therapy.

A Multicenter Japanese Survey Assessing the Long-term Outcomes of Liver Retransplantation Using Living Donor Grafts.

BACKGROUND: Liver transplantation is the most suitable treatment option available for end-stage liver disease. However, some patients require retransplantation, despite medical advances that have led to improved survival. We aimed to compile a definitive, nationwide resource of liver retransplantation data in Japan, seeking to identify the predictors of patient survival posttransplantation. METHODS: Questionnaires were sent to 32 institutions that had conducted 281 retransplantations before 2015. RESULTS: Among the 265 patients included in this study (142 pediatric cases), the average age at primary transplantation was 23 years, and retransplantation was performed after an average of 1468 days. The main indication for retransplantation was graft rejection (95 patients). Living-donor liver transplantation accounted for 94.7% of primary transplantations and 73.2% of retransplantations. Patient survival at 1, 3, or 5 years did not differ by type of transplantation but was better for pediatric (70.8%, 68.3%, and 60.1%, respectively) than for adult (57.2%, 50.4%, and 45.2%, respectively) recipients (P = 0.0003). Small-for-size syndrome, retransplantation within 365 days, and inpatient status at retransplantation were significant predictors of poor survival in pediatric cases. Retransplantation within 365 days and conditions warranting retransplantation were significant predictors of poor survival in adult patients. CONCLUSIONS: In Japan, where >70% of retransplantations are performed using living donors, the indications and timing are different from those in previous reports from other countries, while maintaining comparable survival rates. Considering technical challenges, graft failure within 365 days should be thoroughly restricted to justify the use of living donor.

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.

Long-term growth of intrahepatic papillary neoplasms: A case report.

BACKGROUND: Intraductal papillary neoplasm of the bile duct (IPNB) is a type of tumor that presents in the intra- or extrahepatic bile ducts. Cystic-type intrahepatic IPNB often mimics simple liver cysts, making the diagnosis difficult. Because the growth of IPNB is slow, careful follow-up and timely therapeutic intervention is recommended. There are few reports with a follow-up period longer than a decade; thus, we report the case of a patient with an IPNB that grew for over 13 years. CASE SUMMARY: A 65-year-old man was diagnosed, 13 years prior with a cystic hepatic tumor with abnormal imaging findings. The targeted tumor biopsy results showed no malignancy. Biannual follow-up examinations were performed because of the potential for malignancy. The cystic lesions showed gradual enlargement over 11 years and a 4 mm papillary proliferation appeared on the cyst wall, which is compatible with IPNB. The tumor was observed for another 2 years because of the patient's wishes. The imaging findings showed enlargement to 8 mm and a new 9 mm papillary proliferation of the cystic tumor. Contrast-enhanced ultrasonography showed hyperenhancement during the arterial phase in both cyst walls, indicating intraductal tumor progression in both tumors. Thus, liver segment 8 subsegmentectomy was performed. The pathological findings indicated that the tumors contained mucin, and high-grade atypia was observed in the papillary lesions, showing IPNB. CONCLUSION: The development of IPNB should be monitored in patients with cystic lesions and ultrasonography are useful tool for the evaluation.

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 (HRASV12), 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.

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.

Expanded living-donor liver transplantation criteria for patients with hepatocellular carcinoma based on the Japanese nationwide survey: the 5-5-500 rule - a retrospective study.

Expansion of the liver transplantation indication criteria for patients with hepatocellular carcinoma (HCC) has long been debated. Here we propose new, expanded living-donor liver transplantation (LDLT) criteria for HCC patients based on a retrospective data analysis of the Japanese nationwide survey. A total of 965 HCC patients undergoing LDLT were included, 301 (31%) of whom were beyond the Milan criteria. Here, we applied the Greenwood formula to investigate new criteria enabling the maximal enrollment of candidates while securing a 5-year recurrence rate (95% upper confidence limit) below 10% by examining various combinations of tumor numbers and serum alpha-fetoprotein values, and maintaining the maximal nodule diameter at 5 cm. Finally, new expanded criteria for LDLT candidates with HCC, the 5-5-500 rule (nodule size ≤5 cm in diameter, nodule number ≤5, and alfa-fetoprotein value ≤500 ng/ml), were established as a new regulation with a 95% confidence interval of a 5-year recurrence rate of 7.3% (5.2-9.3) and a 19% increase in the number of eligible patients. In addition, the 5-5-500 rule could identify patients at high risk of recurrence, among those within and beyond the Milan criteria. In conclusion, the new criteria - the 5-5-500 rule - might provide rational expansion for LDLT candidates with HCC.

National survey of de novo malignancy after solid organ transplantation in Japan.

PURPOSE: In Japan, there have been no national surveys on the incidence of de novo malignancy after solid organ transplantation, which is one of the leading causes of death in transplant recipients. METHODS: A questionnaire was distributed to institutions that perform solid organ transplantation in Japan, and clinical information was collected from patients who underwent transplantation between 2001 and 2010 and who exhibited de novo malignancies. RESULTS: Nine thousand two hundred ten solid organ transplants (kidney, 49.9%; liver, 45.9%; heart, 0.9%; lung, 1.2%; pancreas, 1.9%; small intestine, 0.2%) were performed. Four hundred seventy-nine (5.2%) cases of de novo malignancy were identified. The transplanted organs of the patients included the kidney (n = 479, 54.8%), liver (n = 186, 38.8%), heart (n = 5, 0.1%), lung (n = 18, 3.8%), pancreas (n = 9, 1.9%), and small intestine (n = 1, 0.02%). The most common malignancies were post-transplant lymphoproliferative disorder (n = 87) and cancers of the kidney (n = 43), stomach (n = 41), large intestine (n = 41), and lung (n = 36). CONCLUSIONS: This is the first national survey of the incidence of de novo malignancy in Japan. Further study is required to identify the risk of de novo malignancy in organ transplant recipients in comparison to the general population, namely the standardized incidence ratio.

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.

Liver transplantation for biliary atresia: a systematic review.

Biliary atresia (BA) is an idiopathic neonatal cholangiopathy characterized by progressive inflammatory obliteration of the intrahepatic or extrahepatic bile ducts. Although the Kasai operation has dramatically improved the outcomes in children with BA, most patients with BA eventually require liver transplantation (LT) even after undergoing a successful Kasai procedure. The Japanese LT Society (JLTS) was established in 1980 to characterize and follow trends in patient characteristics and the graft survival among all liver transplant patients in Japan. The 1-, 5-, 10-, 15- and 20-year survival rates for the patients and grafts undergoing living donor LT were 91.6, 91.5, 87.1, 85.4 and 84.2 and 90.5, 90.4, 84.6, 82.0 and 79.9%, respectively. LDLT was able to be performed even in patients weighing less than 5 kg with early liver failure following a Kasai operation using a reduced left lateral segments. As LT has been revealed to increase the donor pool and decrease the waiting list mortality with an excellent long-term graft survival, early referral to a transplant center should be considered when at least one complication of cirrhosis occurs during its natural history, especially in adolescents.

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-3ß, respectively, and >60% of CC cases were positive for both phosphorylated glycogen synthase kinase--3ß 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.

Cerebral Infarction by Paradoxical Gas Embolism During Laparoscopic Liver Resection with Injury of the Hepatic Vessels in a Patient without a Right-to-Left Systemic Shunt.

BACKGROUND Carbon dioxide (CO2) is believed to be the safest gas for laparoscopic surgery, which is a standard procedure. We experienced severe cerebral infarction caused by paradoxical CO2 embolism during laparoscopic liver resection with injury of the hepatic vessels despite the absence of a right-to-left systemic shunt. CASE REPORT A 60-year-old man was diagnosed with hepatocellular carcinoma in the right hepatic lobe secondary to alcoholic liver disease. We planned the laparoscopy-assisted liver resection. During the surgery, the root of the right hepatic vein was injured. A 1.5-cm hole was accidentally made in the right hepatic vein, while mobilizing the right hepatic lobe laparoscopically. End-tidal CO2 dropped from 39 to 15.5 mmHg, and systemic blood pressure dropped from 121 to 45 mmHg, returning to normal with the administration of inotropes. The transesophageal echocardiography revealed numerous bubbles in the left atrium and ventricle. The Bispectral Index monitoring system showed low brain activity, suggesting cerebral infarction due to paradoxical gas embolism. The hepatectomy was completed by conversion to open laparotomy. The patient went into a coma and suffered quadriplegia after surgery, despite the cooling of his head and the administration of Thiamylal. Brain MRI revealed cerebral infarction in the broad area of the cerebral cortex right side predominantly, with poor blood flow confirmed by the brain perfusion single-photon emission CT. Rehabilitation was gradually achieved with Botox injections. CONCLUSIONS Cerebral infarction by paradoxical gas embolism is a rare complication in laparoscopic surgery, but it is important to be aware of the risk and to be prepared to treat it.