Hayato Nakagawa

Radiofrequency Ablation for Hepatocellular Carcinoma: 10-Year Outcome and Prognostic Factors

OBJECTIVES:Radiofrequency ablation (RFA) is widely performed for hepatocellular carcinoma (HCC). However, there has been no report on 10-year outcome of RFA. The objective of this study was to report a 10-year consecutive case series at a tertiary referral center.METHODS:We performed 2,982 RFA treatments on 1,170 primary HCC patients and analyzed a collected database.RESULTS:Final computed tomography images showed complete tumor ablation in 2,964 (99.4%) of 2,982 treatments performed for the 1,170 primary HCC patients. With a median follow-up of 38.2 months, 5- and 10-year survival rates were 60.2% (95% confidence interval (CI): 56.7–63.9%) and 27.3% (95% CI: 21.5–34.7%), respectively. Multivariate analysis demonstrated that age, antibody to hepatitis C virus (anti-HCV), Child-Pugh class, tumor size, tumor number, serum des-γ-carboxy-prothrombin (DCP) level, and serum lectin-reactive α-fetoprotein level (AFP-L3) were significantly related to survival. Five- and 10-year local tumor progression rates were both 3.2% (95% CI: 2.1–4.3%). Serum DCP level alone was significantly related to local tumor progression. Five- and 10-year distant recurrence rates were 74.8% (95% CI: 71.8–77.8%) and 80.8% (95% CI: 77.4–84.3%), respectively. Anti-HCV, Child-Pugh class, platelet count, tumor size, tumor number, serum AFP level, and serum DCP level were significantly related to distant recurrence. There were 67 complications (2.2%) and 1 death (0.03%).CONCLUSIONS:RFA could be locally curative for HCC, resulting in survival for as long as 10 years, and was a safe procedure. RFA might be a first-line treatment for selected patients with early-stage HCC.

Deletion of Apoptosis Signal-Regulating Kinase 1 Attenuates Acetaminophen-Induced Liver Injury by Inhibiting c-Jun N-Terminal Kinase Activation

BACKGROUND & AIMS Acetaminophen (APAP) overdose is the most frequent cause of drug-induced liver failure. C-jun N-terminal kinase (JNK) is thought to play a central role in APAP-induced liver injury, although its upstream activator has not yet been identified. Apoptosis signal-regulating kinase 1 (ASK1) is a member of the mitogen-activated protein kinase kinase kinase family and is important for stress-induced JNK activation. We tested the hypothesis that ASK1 was involved in APAP-induced JNK activation and liver injury. METHODS ASK1-deficient (ASK1(-/-)) mice and wild-type (WT) mice were given 300 mg/kg of APAP. Serum alanine aminotransferase levels and liver histology were assessed. To investigate the involvement of ASK1 in direct hepatocellular damage and the subsequent inflammatory response, we used primary hepatocytes and splenocytes from WT and ASK1(-/-) mice. RESULTS In ASK1(-/-) mouse liver, APAP toxicity was attenuated significantly and the prolonged activation of JNK was inhibited. In addition, thioredoxin, a direct ASK1 inhibitor, dissociated from ASK1 after APAP overdose with concomitant ASK1 activation. Although the prolonged activation of p38 also was attenuated in ASK1(-/-) mice, the p38 signaling pathway was not likely to be involved in APAP-induced liver injury. Primary hepatocyte culture also revealed that ASK1 and JNK, but not p38, contributed to direct APAP-induced cellular damage. CONCLUSIONS Our data suggest that ASK1 is activated by APAP overdose, most likely via a mechanism involving thioredoxin-ASK1 dissociation, and that it plays a role in APAP-induced liver injury through JNK activation.

Constitutive NF-κB Activation in Colorectal Carcinoma Plays a Key Role in Angiogenesis, Promoting Tumor Growth

Purpose: Nuclear factor κB (NF-κB) is an important transcription factor in various biological processes. Constitutive NF-κB activation has been noted in many tumors, including colorectal cancers. However, the precise role of this activation in colorectal cancer is unclear. Experimental Design: Constitutive NF-κB activation was evaluated in colorectal cancer tissues and cell lines. To inhibit NF-κB activation, we established cancer cells with stable knockdown of IκB kinase γ (NF-κB essential modulator), which is the regulatory subunit of the IκB kinase complex, by RNA interference. Cell growth and apoptosis were evaluated in wild-type cells (WT) and knocked-down cells (KD). Microarray and protein array analysis were also done. To determine involvement of angiogenesis, human umbilical vein endothelial cells were used. By s.c. transplantation of the cells into nude mice, tumor sizes, vascularity, and chemodrug sensitivity were analyzed. Results: Constitutive NF-κB activation was observed in 40% of colorectal cancer tissues and 67% of cell lines. Cell proliferation was not different between WT and KD in vitro, whereas apoptosis mediated by tumor necrosis factor-α and 5-fluorouracil were increased in KD. Several angiogenic chemokines were decreased in KD. Human umbilical vein endothelial cells incubated in WT supernatant showed more branch points than in KD, suggesting that constitutive NF-κB activation was involved in angiogenesis. Subcutaneous tumor expansion was suppressed to 23% in KD, and vessels were also decreased. By 5-fluoruracil treatment, tumor expansion was suppressed to a greater extent in KD (to 6%) than in WT (to 50%). Conclusion: NF-κB inhibition may represent a potent treatment modality in colorectal cancer, especially in cases with constitutive NF-κB activation.

ER Stress Cooperates with Hypernutrition to Trigger TNF-Dependent Spontaneous HCC Development

Endoplasmic reticulum (ER) stress has been implicated in the pathogenesis of viral hepatitis, insulin resistance, hepatosteatosis, and nonalcoholic steatohepatitis (NASH), disorders that increase risk of hepatocellular carcinoma (HCC). To determine whether and how ER stress contributes to obesity-driven hepatic tumorigenesis we fed wild-type (WT) and MUP-uPA mice, in which hepatocyte ER stress is induced by plasminogen activator expression, with high-fat diet. Although both strains were equally insulin resistant, the MUP-uPA mice exhibited more liver damage, more immune infiltration, and increased lipogenesis and, as a result, displayed classical NASH signs and developed typical steatohepatitic HCC. Both NASH and HCC development were dependent on TNF produced by inflammatory macrophages that accumulate in the MUP-uPA liver in response to hepatocyte ER stress.

Hybrid Periportal Hepatocytes Regenerate the Injured Liver without Giving Rise to Cancer

Compensatory proliferation triggered by hepatocyte loss is required for liver regeneration and maintenance but also promotes development of hepatocellular carcinoma (HCC). Despite extensive investigation, the cells responsible for hepatocyte restoration or HCC development remain poorly characterized. We used genetic lineage tracing to identify cells responsible for hepatocyte replenishment following chronic liver injury and queried their roles in three distinct HCC models. We found that a pre-existing population of periportal hepatocytes, located in the portal triads of healthy livers and expressing low amounts of Sox9 and other bile-duct-enriched genes, undergo extensive proliferation and replenish liver mass after chronic hepatocyte-depleting injuries. Despite their high regenerative potential, these so-called hybrid hepatocytes do not give rise to HCC in chronically injured livers and thus represent a unique way to restore tissue function and avoid tumorigenesis. This specialized set of pre-existing differentiated cells may be highly suitable for cell-based therapy of chronic hepatocyte-depleting disorders.

Cutting Edge: The IκB Kinase (IKK) Inhibitor, NEMO-Binding Domain Peptide, Blocks Inflammatory Injury in Murine Colitis

Inflammatory mediators such as TNF-α, IL-6, and IL-1 are important in the pathogenesis of inflammatory bowel diseases and are regulated by the activation of NF-κB. The aim of the present study was to investigate whether the NF-κB essential modulator (NEMO)-binding domain (NBD) peptide, which has been shown to block the association of NEMO with the IκB kinaseβ subunit (IKKβ) and inhibit NF-κB activity, reduces inflammatory injury in mice with colitis. Two colitis models were established by the following: 1) inclusion of dextran sulfate sodium salt (DSS) in the drinking water of the mice; and 2) a trinitrobenzene sulfonic acid enema. Marked NF-κB activation and expression of proinflammatory cytokines were observed in colonic tissues. The NBD peptide ameliorated colonic inflammatory injury through the down-regulation of proinflammatory cytokines mediated by NF-κB inhibition in both models. These results indicate that an IKKβ-targeted NF-κB blockade using the NBD peptide could be an attractive therapeutic approach for inflammatory bowel disease.

Serum IL-6 levels and the risk for hepatocarcinogenesis in chronic hepatitis C patients: an analysis based on gender differences

Interleukin‐6 (IL‐6) may play a role in the pathogenesis of hepatocellular carcinoma (HCC). Recently, it was reported in mouse models that estrogen‐mediated inhibition of IL‐6 production explains the gender disparity in HCC. We conducted a retrospective cohort study to examine whether this hypothesis is applicable to human HCC. We enrolled 330 patients with chronic hepatitis C whose serum samples were collected between January 1994 and December 2002. Serum IL‐6 concentrations were measured and patients were divided into three groups according to IL‐6 levels: low, middle, and high. We evaluated the association between serum IL‐6 levels and the risk of subsequent HCC development, including subgroup analysis on each gender. During the follow‐up period (mean 9.0 yr), HCC developed in 126 patients. The incidence rates differed significantly among the three groups (p = 0.015), increasing in accordance with serum IL‐6 levels. However, unexpectedly, this tendency was significant only in female patients. In a multivariate analysis, higher serum IL‐6 level was an independent risk factor for HCC development in female patients, with a hazard ratio of 1.61. Although female patients showed a weak negative correlation between serum IL‐6 levels and estradiol levels, the lower risk of HCC in female patients cannot be fully explained by estrogen‐mediated inhibition of IL‐6 production. In conclusion, higher serum IL‐6 level was an independent risk factor for HCC development in female but not male chronic hepatitis C patients. Measurement of serum IL‐6 levels may provide useful information for predicting future HCC development in female chronic hepatitis C patients.

Sarcopenia, intramuscular fat deposition, and visceral adiposity independently predict the outcomes of hepatocellular carcinoma

BACKGROUND & AIMS Obesity defined by body mass index (BMI) significantly increases the risk of hepatocellular carcinoma (HCC). In contrast, not only obesity but also underweight is associated with poor prognosis in patients with HCC. Differences in body composition rather than BMI were suggested to be true determinants of prognosis. However, this hypothesis has not been demonstrated conclusively. METHODS We measured skeletal muscle index (SMI), mean muscle attenuation (MA), visceral adipose tissue index, subcutaneous adipose tissue index, and visceral to subcutaneous adipose tissue area ratios (VSR) via computed tomography in a large-scale retrospective cohort of 1257 patients with different stages of HCC, and comprehensively analyzed the impact of body composition on the prognoses. RESULTS Among five body composition components, low SMI (called sarcopenia), low MA (called intramuscular fat [IMF] deposition), and high VSR (called visceral adiposity) were significantly associated with mortality, independently of cancer stage or Child-Pugh class. A multivariate analysis revealed that sarcopenia (hazard ratio [HR], 1.52; 95% confidence interval [CI], 1.18-1.96; p=0.001), IMF deposition (HR, 1.34; 95% CI, 1.05-1.71; p=0.020), and visceral adiposity (HR, 1.35; 95% CI, 1.09-1.66; p=0.005) but not BMI were significant predictors of survival. The prevalence of poor prognostic body composition components was significantly higher in underweight and obese patients than in normal weight patients. CONCLUSIONS Sarcopenia, IMF deposition, and visceral adiposity independently predict mortality in patients with HCC. Body composition rather than BMI is a major determinant of prognosis in patients with HCC.

Visceral fat accumulation is an independent risk factor for hepatocellular carcinoma recurrence after curative treatment in patients with suspected NASH

Background and Aim: Visceral fat accumulation reportedly increases the risk of hepatocellular carcinoma (HCC) development in patients with chronic liver disease. However, it has not beeen fully elucidated whether visceral fat accumulation increases the risk of HCC recurrence after curative treatment in patients with suspected non-alcoholic steatohepatitis (NASH). Therefore this was investigated in the current study. Methods: 62 patients with naïve HCC with suspected NASH were enrolled. All were curatively treated with percutaneous radiofrequency ablation between 1999 and 2006. The visceral fat area (VFA) was determined in each patient from CT images, taken at the time of HCC diagnosis. Patients were divided into two groups based on VFA: the high VFA group (>130 cm2 in males, >90 cm2 in females, n = 27) and the others (n = 35). The effects of VFA on HCC recurrence were analysed together with other factors including patients’ background, tumour-related factors and liver function-related factors. Results: The cumulative recurrence rates differed significantly between the two groups; 15.9, 56.5 and 75.1% at 1, 2 and 3 years, respectively, in the high VFA group, and 9.7, 31.1 and 43.1%, respectively, in the controls (p = 0.018). Multivariate analysis indicated visceral fat accumulation (risk ratio 1.08, per 10 cm2, p = 0.046) and older age (risk ratio 1.06 per 1 year, p = 0.04) as independent risk factors of HCC recurrence. Conclusions: Visceral fat accumulation is an independent risk factor of HCC recurrence after curative treatment in patients with suspected NASH.

p62, Upregulated during Preneoplasia, Induces Hepatocellular Carcinogenesis by Maintaining Survival of Stressed HCC-Initiating Cells

p62 is a ubiquitin-binding autophagy receptor and signaling protein that accumulates in premalignant liver diseases and most hepatocellular carcinomas (HCCs). Although p62 was proposed to participate in the formation of benign adenomas in autophagy-deficient livers, its role in HCC initiation was not explored. Here we show that p62 is necessary and sufficient for HCC induction in mice and that its high expression in non-tumor human liver predicts rapid HCC recurrence after curative ablation. High p62 expression is needed for activation of NRF2 and mTORC1, induction of c-Myc, and protection of HCC-initiating cells from oxidative stress-induced death.