Natural regression of fibrosis in chronic hepatitis B

The fibrosis of liver cirrhosis was considered to be irreversible before the anti-viral drugs showed that it is reversible when they lead to continuous suppression of viral replication and inflammation. However, several reports previously showed that fibrosis of type B liver cirrhosis was almost completely absorbed after the natural remission of chronic inflammation. This phenomenon might not be limited to exceptional patients, but rather occur commonly, considering the dynamic clinical features of chronic hepatitis B(CHB), where inactive carrier stage normally follows aggravation of hepatitis and progression of fibrosis at the time of HBe Ag seroconversion. Thus, fibrosis levels of CHB as a hepatocellular carcinoma(HCC)-surveillance marker, particularly those of the inactive stage, could be underestimated, because some of them might have been(pre)cirrhotic in the past and recovered with the natural regression of fibrosis. We argue that cirrhosisinduced HCC mechanisms, rather than direct action of viral genome, may be more common than generally considered in CHB patients. This may have some impact on reconsidering the surveillance rationale for HCC in CHB, from where advanced HCCs tended to be missed. In addition, a molecular marker to assess the cancer-prone characteristics of the liver will definitely be needed to resolve the issue.

Oncogenic role of p21 in hepatocarcinogenesis suggests a new treatment strategy

A well-known tumor suppressor, p21, acts parado-xically by promoting tumor growth in some cellular conditions. These conflicting functions have been demonstrated in association with the HBx gene and in hepatocarcinogenesis. The molecular behavior of p21 depends on its subcellular localization. Nuclear p21 may inhibit cell proliferation and be proapoptotic, while cytoplasmic p21 may have oncogenic and anti-apoptotic functions. Because most typical tumor suppressive proteins also have different effects according to subcellular localization, elucidating the regulatory mechanisms underlying nucleo-cytoplasmic transport of these proteins would be significant and may lead to a new strategy for anti-hepatocellular carcinoma(HCC) therapy. Chromosome region maintenance 1(CRM1) is a major nuclear export receptor involved in transport of tumor suppressors from nucleus to cytoplasm. Expression of CRM1 is enhanced in a variety of malignancies and in vitro studies have shown the efficacy of specific inhibition of CRM1 against cancer cell lines. Interestingly, interferon may keep p21 in the nucleus; this is one of the mechanisms of its anti-hepatocarcinogenic function. Here we review the oncogenic property of p21, which depends on its subcellular localization, and discuss the rationale underlying a new strategy for HCC treatment and prevention.

Impact of continuous positive airway pressure therapy for nonalcoholic fatty liver disease in patients with obstructive sleep apnea

BACKGROUND Obstructive sleep apnea(OSA)has been suggested as an independent risk factor for nonalcoholic fatty liver disease(NAFLD),and continuous positive airway pressure(CPAP)is the first-line therapy for OSA.AIM To clarify the efficacy of effective CPAP therapy on NAFLD of OSA patients by serum markers and transient elastography(TE)using FibroScan®(Echosens,Paris,France).METHODS We prospectively enrolled 123 consecutive patients with OSA who met the indications for CPAP.Liver fibrosis and steatosis were assessed using TE.Before and after 6 mo of CPAP therapy,serum markers and TE were assessed for all patients.The mean usage rate of CPAP therapy for 6 mo was arbitrarily calculated in each patient and expressed as“mean compliance index”(m-CI).RESULTS In 50 OSA patients with NAFLD,both aspartate aminotransferase(AST)and alanine aminotransferase(ALT)levels were significantly decreased after 6 mo of CPAP therapy.Univariate analysis showed that decreased body weight(BW),decreased body mass index(BMI),decreased AST level,decreased hemoglobin A1c,and high m-CI were significantly related with improved ALT level.In multivariate regression model adjusted for quantities of BW change during 6 mo of CPAP therapy,high m-CI tended to improve ALT level(P=0.051).All 17 OSA patients with NAFLD,high m-CI and no BMI changes showed significant improvements in AST and ALT levels.Meanwhile,no significant changes in TE data or serum fibrosis markers were seen.CONCLUSION Some NAFLD could be associated with chronic intermittent hypoxia due to OSA independent of BW changes.In those cases,adequate reoxygenation from effective CPAP therapy may improve NAFLD.

Dental pulp cell bank as a possible future source of individual hepatocytes

Mesenchymal stem cells(MSCs) as a source for regenerative medicine are now the subject of much clinical attention. There are high expectations due to their safety, low tumorigenic risk, and low ethical concerns. MSC therapy has been approved for acute graft-versus host diseases since 2015. Tooth-derived MSCs are known to have a great potential in their proliferation and differentiation capacities, even when compared with bone-marrow-derived MSCs. In particular, stem cells from human exfoliated deciduous teeth(SHEDs) are the best candidates for personal cell banking(dental pulp cell bank), because they can be obtained less invasively in the natural process of individual growth. SHEDs are known to differentiate into hepatocytes. There have been several studies showing the effectiveness of SHEDs on the treatment of liver failure in animal models. They may exert their effects either by repopulation of cells in injured liver or by paracrine mechanisms due to their immuneregulatory functions. Moreover, it may be possible to use each individuals' dental pulp cells as a future source of tailor-made differentiated hepatocytes in the context of a bioartificial liver or liver-on-a-chip to screen for drug toxicity.

Regenerative medicine using dental pulp stem cells for liver diseases

Acute liver failure is a refractory disease and its pro-gnosis, if not treated using liver transplantation, is extremely poor. It is a good candidate for regenerative medicine, where stem cell-based therapies play a central role. Mesenchymal stem cells(MSCs) are known to differentiate into multiple cell lineages including hepatocytes. Autologous cell transplant without any foreign gene induction is feasible using MSCs, thereby avoiding possible risks of tumorigenesis and immune rejection. Dental pulp also contains an MSC population that differentiates into hepatocytes. A point worthy of special mention is that dental pulp can be obtained from deciduous teeth during childhood and can be subsequently harvested when necessary after deposition in a tooth bank. MSCs have not only a regenerative capacity but also act in an anti--inflammatory manner via paracrine mechanisms. Promising efficacies and difficulties with the use of MSC derived from teeth are summarized in this review.

Efficacy and safety of telaprevir- and simeprevir-based triple therapies for older patients with chronic hepatitis C

AIMTo evaluate and compare the efficacy and safety of telaprevir (TVR)-and simeprevir (SMV)-based triple therapies in elderly patients, specifically patients aged 66 years or older. METHODSThe present study enrolled 112 and 76 Japanese patients with chronic hepatitis C virus genotype 1b infection who were treated with a 12-wk TVR-based or SMV-based triple therapy, respectively, followed by a dual therapy that included pegylated interferon α and ribavirin (RBV) for 12 wk. The patients were categorized into two groups according to age as follows: A younger group of patients aged ≤ 65 years old and an older group of patients aged > 65 years old. Among the patients treated with TVR-based triple therapy, 34 patients were included in the older group. The median ages were 56 years (range: 28-65 years) in the younger group and 69 years (range: 66-81 years) in the older group. Among the patients treated with SMV-based triple therapy, 39 patients were included in the older group. The median ages were 59 years (range: 36-65 years) in the younger group and 71 years (range: 66-86 years) in the older group. The clinical, biochemical and virological data were analyzed before and during treatment. RESULTSAmong the patients treated with the TVR-based triple therapy, no significant difference in the sustained virological response (SVR) was found between the younger (80.8%) and older (88.2%) groups. The SVR rates for patients with the interleukin 28B (IL28B) (rs8099917) TG/GG-genotypes (73.9% and 60.0% in the younger and older groups, respectively) were significantly lower than for patients with the IL28B TT-genotype (86.3% and 92.9%, respectively). The cumulative exposure to RBV for the entire 24-wk treatment period (as a percentage of the target dose) was significantly higher in the younger group than in the older group (91.7% vs 66.7%, respectively, P vs 81.9%, respectively). A multivariate analysis identified the TT-genotype of IL28B (OR = 8.160; 95%CI: 1.593-41.804, P = 0.012) and the adherence of RBV (> 60%) (OR = 11.052; 95%CI: 1.160-105.273, P = 0.037) as independent factors associated with the SVR. Adverse events resulted in discontinuation of the treatment in 11.3% and 14.7% of the younger and older groups, respectively. Among the patients treated with the SMV-based triple therapy, no significant difference in the SVR rare was found between the younger (81.1%) and older (82.1%) groups. The SVR rates for patients with the IL28B TG/GG-genotypes (77.8% and 64.7% in the younger and older groups, respectively) were significantly lower than for patients with the IL28B TT-genotype (88.2% and 100%, respectively). A multivariate analysis identified the TT-genotype of IL28B as an independent factor associated with the SVR (OR = 9.677; 95%CI: 1.114-84.087, P = 0.040). Adverse events resulted in discontinuation of the treatment in 7.0% and 14.3% of patients in the younger and older groups, respectively. CONCLUSIONBoth TVR- and SMV-based triple therapies can be successfully used to treat patients aged 66 years or older with genotype 1b chronic hepatitis C. Genotyping of the IL28B indicates a potential to achieve SVR in these difficult-to-treat elderly patients.

Direct antiviral agent treatment of decompensated hepatitis C virus-induced liver cirrhosis

Recently, direct antiviral agents(DAAs) have been increasingly used for the treatment of chronic hepatitis C virus(HCV) infections, replacing interferon-based regimens that have severe adverse effects and low tolerability. The constant supply of new DAAs makes shorter treatment periods with enhanced safety possible. The efficacy of DAAs for treatment of compensated liver cirrhosis(LC) is not less than that for treatment of non-cirrhotic conditions. These clinical advantages have been useful in pre- and post-liver transplantation(LT) settings. Moreover, DAAs can be used to treat decompensated HCV-induced LC in elderly patients or those with severe complications otherwise having poor prognosis. Although encouraging clinical data are beginning to appear, the actual efficacy of DAAs for suppressing disease progression, allowing delisting for LT and, most importantly, improving prognosis of patients with decompensated HCV-LC remains unknown. Casecontrol studies to examine the short- or long-term effects of DAAs for treatment of decompensated HCV-LC are urgently need.

Contributions of transgenic mouse studies on the research of hepatitis B virus and hepatitis C virus-induced hepatocarcinogenesis

Transgenic mouse technology has enabled the investigation of the pathogenic effects, including those on development, immunological reactions and carcinogenesis, of viral genes directly in living organism in a real-time manner. Although viral hepatocarcinogenesis comprises multiple sequences of pathological events, that is, chronic necroinflammation and the subsequent regeneration of hepatocytes that induces the accumulation of genetic alterations and hepatocellular carcinoma(HCC), the direct action of viral proteins also play significant roles. The pathogenesis of hepatitis B virus X and hepatitis C virus(HCV) core genes has been extensively studied by virtue of their functions as a transactivator and a steatosis inducer, respectively. In particular, the mechanism of steatosis in HCV infection and its possible association with HCC has been well studied using HCV core gene transgenic mouse models. Although transgenic mouse models have remarkable advantages, they are intrinsically accompanied by some drawbacks when used to study human diseases. Therefore, the results obtained from transgenic mouse studies should be carefully interpreted in the context of whether or not they are well associated with human pathogenesis.

Multicentric occurrence of hepatocellular carcinoma with nonalcoholic steatohepatitis

AIM:To reveal the manner of hepatocellular carcinoma (HCC) development in patients with nonalcoholic steatohepatitis(NASH) focusing on multicentric occurrence (MO) of HCC.METHODS:We compared clinicopathological characteristics between patients with and without MO of HCC arising from NASH background.The clinical features were implicated with reference to the literature available.RESULTS:MO of HCC was identified with histological proof in 4 out of 12 patients with NASH-related HCC(2 males and 2 females).One patient had synchronous MO;an advanced HCC,two well-differentiated HCCs and a dysplastic nodule,followed by the development of metachronous MO of HCC.The other three patients had multiple advanced HCCs accompanied by a well-differentiated HCC or a dysplastic nodule.Of these three patients,one had synchronous MO,one had metachronous MO and the other had both synchronous and metachronous MO.There were no obvious differences between the patients with or without MO in terms of liver function tests,tumor markers and anatomical extent of HCC.On the other hand,all four patients with MO of HCC were older than 70 years old and had the comorbidities of obesity,type 2 diabetes mellitus(T2DM),hypertension and cirrhosis.Although these conditions were not limited to MO of HCC,all the conditions were met in only one of eight patients without MO of HCC.Thus,concurrence of these conditions may be a predisposing situation to synchronous MO of HCC.In particular,old age,T2DM and cirrhosis were suggested to be prerequisite for MO because these factors were depicted in common among two other cases with MO of HCC under NASH in the literature.CONCLUSION:The putative predisposing factors and necessary preconditions for synchronous MO of HCC in NASH were suggested in this study.Further investigations are required to clarify the accurate prevalence and predictors of MO to establish better strategies for treatment and prevention leading to the prognostic improvement in NASH.

Practical Use of Transient Elastography in Screening for Nonalcoholic Steatohepatitis in a Japanese Population

Background and Aims:Fatty infiltration of liver may induce insulin resistance(IR),and a proportion of patients with nonalcoholic fatty liver disease(NAFLD)is diagnosed with nonalcoholic steatohepatitis.Transient elastography is gaining popularity as a means of non-invasively determining both liver stiffness(fibrosis level)and degree of fatty infiltration,expressed as controlled attenuation parameter(CAP)value.Methods:The aims of this study were to investigate the association between IR and level of fatty liver,and to identify the group at a greater risk of nonalcoholic steatohepatitis using transient elastography and other noninvasive fibrosis markers.A total of 169 patients without chronic hepatitis B and C were analyzed.Results:The CAP value was significantly associated with IR(HOMA-IR≥2.5;AUROC=0.81),and the optimal cut-off to discriminate IR was 264 dB/m.The liver stiffness measurement and aspartate aminotransferase-to-platelet ratio index values were significantly higher for CAP≥264 than in CAP<264.The 9 patients among the overall 169 patients(5.3%)and among the 102 NAFLD patients(8.8%)who showed≥264 dB and≥7.0 kPa in transient elastography could represent good candidates for liver biopsy.Conclusions:Evaluation of NAFLD based on CAP values was useful in diagnosing IR.About 9%of NAFLD patients in a Japanese outpatient clinic with a few metabolic complications might be considered good candidates for liver biopsy to confirm nonalcoholic steatohepatitis.