Irreversible electroporation (IRE) is a newly developed non-thermal ablative therapy. During the IRE procedure, the permeability of the cell membrane is irreversibly changed by application of high-energy pulses across the tissue. This induces the breakdown of cell homeostasis, and thereby cell death. Here, we present an in vivo study to demonstrate IRE ablation of gastric tissue and characterize the changes that occur with time therein. No significant complications were observed in the test rats during the experiment. The electroporated tissues exhibited apoptosis at 10, 24 and 48 h after IRE ablation. The apoptosis peaked at 10 h after IRE and then declined, suggesting that the ablated tissue rapidly recovered owing to intense metabolic activity. In addition, the electroporated tissues exhibited morphological changes such as pyknosis and karyorrhexis, while histological analysis showed that the blood vessels were preserved. Interestingly, electroporation greatly affected the mucosa and muscularis propria, but not the submucosa and serosa. This study suggests that IRE could potentially be used as a minimally invasive treatment for early gastric cancer that does not exhibit lymph node metastasis or dysplasia.

Genetically engineered mouse cancer models allow tumors to be imaged in vivo via co-expression of a reporter gene with a tumor-initiating gene. However, differential transcriptional and translational regulation between the tumor-initiating gene and the reporter gene can result in inconsistency between the actual tumor size and the size indicated by the imaging assay. To overcome this limitation, we developed a transgenic mouse in which two oncogenes, encoding P53(R172H) and KRAS(G12D), are expressed together with two reporter genes, encoding enhanced green fluorescent protein (EGFP) and firefly luciferase, in a single open reading frame following Cre-mediated DNA excision. Systemic administration of adenovirus encoding Cre to these mice induced specific transgene expression in the liver. Repeated bioluminescence imaging of the mice revealed a continuous increase in the bioluminescent signal over time. A strong correlation was found between the bioluminescent signal and actual tumor size. Interestingly, all liver tumors induced by P53(R172H) and KRAS(G12D) in the model were hepatocellular adenomas. The mouse model was also used to trace cell proliferation in the epidermis via live fluorescence imaging. We anticipate that the transgenic mouse model will be useful for imaging tumor development in vivo and for investigating the oncogenic collaboration between P53(R172H) and KRAS(G12D).

Routine nucleos(t)ide analogs (NUCs) have not yet been recommended for patients with immune-tolerant (IT) phase in chronic hepatitis B virus (HBV) infection. We aimed to evaluate prognosis of patients in untreated IT-phase (UIT group), compared to those in immune-active phase who achieved virological response by NUCs according to guidelines (VR group). Between 2006 and 2012, patients in UIT or VR groups were included. Cumulative risks of HCC and liver-related events (LREs) development were assessed. Furthermore, propensity-score was calculated based upon age, gender, diabetes and liver stiffness. UIT group (n = 126) showed younger age, lower proportion of male gender and lower LS than VR group (n = 641). UIT group had similar 10-year cumulative risks of HCC (2.7% vs. 2.9%, p = 0.704) and LRE (4.6% vs. 6.1%, p = 0.903) development, compared to VR group. When we re-defined UIT group by the lower ALT cut-offs, 10-year cumulative risks of HCC and LRE development were 2.9% and 4.8%, respectively. Using propensity-score matching and inverse probability treatment weighting analysis, similar results were reproduced. UIT group consistently had similar prognosis compared to VR group. Therefore, further large-scale prospective studies in order to verify rationales of routine NUCs in UIT group are still required.

Sodium taurocholate cotransporting polypeptide (NTCP) was identified as an entry receptor for hepatitis B virus (HBV) infection. The substitution of serine at position 267 of NTCP with phenylalanine (S267F) is an Asian-specific variation that hampers HBV entry in vitro. In this study, we aimed to evaluate the prevalence of S267F polymorphism in Korean patients with chronic hepatitis B (CHB) and its association with disease progression and potential viral evolution in the preS1 domain of HBV. We found that the frequency of the S267F variant of NTCP in CHB patients and controls was 2.7% and 5.7% (P = 0.031), respectively, and that those who had S267F variant were less susceptible to chronic HBV infection. The frequency of the S267F variant in CHB, cirrhosis and hepatocellular carcinoma (HCC) patients was 3.3%, 0.9%, and 3.5%, respectively. Thus, the S267F variant correlated significantly with a lower risk for cirrhosis (P = 0.036). Sequencing preS1 domain of HBV from the patients who had S267F variant revealed no significant sequence change compared to the wild type. In conclusion, the S267F variant of NTCP is clinically associated with a lower risk of chronic HBV infection and cirrhosis development, which implicates suppressing HBV entry could reduce the disease burden.

Non-alcoholic fatty liver disease (NAFLD) is a dominant cause of chronic liver disease, but the exact mechanism of progression from simple steatosis to nonalcoholic steatohepatitis (NASH) remains unknown. Here, we investigated the role of exosomes in NAFLD progression. Exosomes were isolated from a human hepatoma cell line treated with palmitic acid (PA) and their miRNA profiles examined by microarray. The human hepatic stellate cell (HSC) line (LX-2) was then treated with exosome isolated from hepatocytes. Compared with controls, PA-treated hepatocytes displayed significantly increased CD36 and exosome production. The microarray analysis showed there to be distinctive miRNA expression patterns between exosomes from vehicle- and PA-treated hepatocytes. When LX-2 cells were cultured with exosomes from PA-treated hepatocytes, the expression of genes related to the development of fibrosis were significantly amplified compared to those treated with exosomes from vehicle-treated hepatocytes. In conclusion, PA treatment enhanced the production of exosomes in these hepatocytes and changed their exosomal miRNA profile. Moreover, exosomes derived from PA-treated hepatocytes caused an increase in the expression levels of fibrotic genes in HSCs. Therefore, exosomes may have important roles in the crosstalk between hepatocytes and HSCs in the progression from simple steatosis to NASH.