Tomohiro Tanaka

Musashino Red Cross Hospital, Tokyo, Tokyo-to, Japan

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Publications (7)39.2 Total impact

  • Article: Changes in hepatitis C viral load during first 14 days can predict the undetectable time point of serum viral load by pegylated interferon and ribavirin therapy
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    ABSTRACT: Aim:  In the treatment of chronic hepatitis C, pegylated interferon (PEG-IFN) and ribavirin combination therapy must be continued for an adequate duration to improve the rate of sustained virological response. We attempted to predict the time point at which serum hepatitis C virus (HCV) RNA are undetectable during combination therapy.Methods:  Patients with HCV genotype 1b were enrolled in a model preparation (n = 35) and a validation group (n = 70). All patients received PEG-IFN-α-2b/ribavirin combination therapy for at least 48 weeks, and serological samples were screened a minimum of 17 times during the therapy. Serum HCV RNA were measured by the Abbott RealTime HCV assay. Using the HCV dynamics model described by Neumann et al., we used multiple linear regression analysis to select factors that affected the undetectable time point.Results:  Difference in viral load between weeks 1 and 2 was the only predictive factor for the undetectable time point of serum HCV RNA (r2 = 0.67, P < 0.0005), and we derived the following prediction equation: undetectable time point (week) = 13.495 × (viral load at day 14 [log IU/mL] − viral load at day 7 [log IU/mL]) + 25.456. The equation was applicable to the validation group.Conclusion:  We created a formula for predicting the undetectable time point from viral load measurements early in PEG-IFN-α-2b/ribavirin combination therapy. An early response reflects sensitivity to therapy, and the estimation of an undetectable time point would be useful for determining the optimal duration of treatment for chronic hepatitis C patients.
    Hepatology Research 02/2011; 41(3):217 - 224. · 2.20 Impact Factor
  • Article: Hepatic steatosis in chronic hepatitis C is a significant risk factor for developing hepatocellular carcinoma independent of age, sex, obesity, fibrosis stage and response to interferon therapy
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    ABSTRACT: Aim:  Hepatic steatosis is linked to development of hepatocellular carcinoma (HCC) in non-viral liver disease such as non-alcoholic steatohepatitis. The present study aimed to assess whether hepatic steatosis is associated with the development of HCC in chronic hepatitis C.Methods:  We studied a retrospective cohort of 1279 patients with chronic hepatitis C who received interferon (IFN) therapy between 1994 and 2005 at a single regional hospital in Japan. Of these patients, 393 had a sustained virological response (SVR) and 886 had non-SVR to IFN therapy. After IFN therapy, these patients were screened for development of HCC every 6 months. The average period of observation was 4.5 years.Results:  HCC developed in 68 patients. The annual incidence of HCC was 2.73% for patients with a steatosis grade of 10% or greater and 0.69% for patients with a steatosis grade of 0–9%. On multivariate analysis, higher grade of steatosis was a significant risk factor for HCC independent of older age, male sex, higher body mass index (BMI), advanced fibrosis stage and non-SVR to IFN therapy. The adjusted risk ratio of hepatic steatosis was 3.04 (confidence interval 1.82–5.06, P < 0.0001), which was higher than that of older age (1.09), male sex (2.12), non-SVR to IFN (2.43) and higher BMI (1.69).Conclusion:  Hepatic steatosis is a significant risk factor for development of HCC in chronic hepatitis C independent of other known risk factors, which suggest the possibility that amelioration of hepatic steatosis may prevent hepatocarcinogenesis.
    Hepatology Research 08/2010; 40(9):870 - 877. · 2.20 Impact Factor
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    Article: Effect of aging on risk for hepatocellular carcinoma in chronic hepatitis C virus infection.
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    ABSTRACT: An increase in the aging population is an impending problem. A large cohort study was carried out to determine the influence of aging and other factors on hepatocarcinogenesis in patients treated with interferon. Biopsy-proven 2547 chronic hepatitis C patients registered at our referral center since 1992 were included. Of these, 2166 were treated with interferon-based therapy. Incidences of hepatocellular carcinoma (HCC) associated with interferon were analyzed by Kaplan-Meier and person-years methods for an average follow-up of 7.5 years. Factors associated with HCC risk were determined by Cox proportional hazard analysis. HCC developed in 177 interferon-treated patients. The risk for HCC depended on age at primary biopsy and increased more than 15-fold after 65 years of age. Even when stratified by stage of fibrosis, the cumulative and annual incidences of HCC were significantly higher in older patients than in younger patients (P < 0.001) at the same stage of fibrosis, except for cirrhosis. Progression of fibrosis over time was significantly accelerated in older patients. The impact of viral eradication on HCC prevention was less significant in older patients than in younger patients. Multivariate analysis confirmed that age, gender, liver fibrosis, liver steatosis, total cholesterol level, fasting blood sugar level, baseline and postinterferon alpha-fetoprotein level, and virological response to interferon were independent risk factors associated with HCC. Aging was the strongest risk factor for a nonvirological response to interferon-based antiviral therapy. Conclusion: Elderly patients are at a higher risk for HCC. Hepatitis C viral eradication had a smaller effect on hepatocarcinogenesis in older patients. Patients should therefore be identified at an earlier age and treatment should be initiated.
    Hepatology 08/2010; 52(2):518-27. · 11.66 Impact Factor
  • Article: A predictive model of response to peginterferon ribavirin in chronic hepatitis C using classification and regression tree analysis.
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    ABSTRACT: Aim: Early disappearance of serum hepatitis C virus (HCV) RNA is the prerequisite for achieving sustained virological response (SVR) in peg-interferon (PEG-IFN) plus ribavirin (RBV) therapy for chronic hepatitis C. This study aimed to develop a decision tree model for the pre-treatment prediction of response. Methods: Genotype 1b chronic hepatitis C treated with PEG-IFN alpha-2b and RBV were studied. Predictive factors of rapid or complete early virological response (RVR/cEVR) were explored in 400 consecutive patients using a recursive partitioning analysis, referred to as classification and regression tree (CART) and validated. Results: CART analysis identified hepatic steatosis (<30%) as the first predictor of response followed by low-density-lipoprotein cholesterol (LDL-C) (>/=100 mg/dL), age (<50 and <60 years), blood sugar (<120 mg/dL), and gamma-glutamyltransferase (GGT) (<40 IU/L) and built decision tree model. The model consisted of seven groups with variable response rates from low (15%) to high (77%). The reproducibility of the model was confirmed by the independent validation group (r(2) = 0.987). When reconstructed into three groups, the rate of RVR/cEVR was 16% for low probability group, 46% for intermediate probability group and 75% for high probability group. Conclusions: A decision tree model that includes hepatic steatosis, LDL-C, age, blood sugar, and GGT may be useful for the prediction of response before PEG-IFN plus RBV therapy, and has the potential to support clinical decisions in selecting patients for therapy and may provide a rationale for treating metabolic factors to improve the efficacy of antiviral therapy.
    Hepatology Research 04/2010; 40(4):251-60. · 2.20 Impact Factor
  • Article: [Epithelioid hemangioendothelioma of the liver diagnosed by laparoscopy guided biopsy].
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    ABSTRACT: A 35-year-old woman was admitted to our hospital for right upper quadrant pain and multiple liver tumor were detected by diagnostic imaging. Tumors located near the surface of the liver which accompanied capsular retraction. Diagnostic laparoscopy showed multiple white tone tumors with retraction of the adjacent liver capsule. Tumor targeted biopsy was performed. The pathologic diagnosis of epithelioid hemangioendothelioma (EHE) was made by the positive staining of factor VIII-related antigen. EHE tend to locate in peripheral and extend to the liver capsule. Therefore, we face difficulties in getting biopsy sample safely. Here we report a useful case of laparoscopic examination and biopsy in the diagnosis of EHE.
    Nippon Shokakibyo Gakkai zasshi The Japanese journal of gastro-enterology 12/2008; 105(11):1640-7.
  • Article: Potential relevance of cytoplasmic viral sensors and related regulators involving innate immunity in antiviral response.
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    ABSTRACT: Clinical significance of molecules involving innate immunity in treatment response remains unclear. The aim is to elucidate the mechanisms underlying resistance to antiviral therapy and predictive usefulness of gene quantification in chronic hepatitis C (CH-C). We conducted a human study in 74 CH-C patients treated with pegylated interferon alpha-2b and ribavirin and 5 nonviral control patients. Expression of viral sensors, adaptor molecule, related ubiquitin E3-ligase, and modulators were quantified. Hepatic RIG-I, MDA5, LGP2, ISG15, and USP18 in CH-C patients were up-regulated at 2- to 8-fold compared with nonhepatitis C virus patients with a relatively constitutive Cardif. Hepatic RIG-I, MDA5, and LGP2 were significantly up-regulated in nonvirologic responders (NVR) compared with transient (TR) or sustained virologic responders (SVR). Cardif and RNF125 were negatively correlated with RIG-I and significantly suppressed in NVR. Differences among clinical responses in RIG-I/Cardif and RIG-I/RNF125 ratios were conspicuous (NVR/TR/SVR = 1.3:0.6:0.4 and 2.3:1.3:0.8, respectively). Like viral sensors, ISG15 and USP18 were significantly up-regulated in NVR (4-fold and 2.3-fold, respectively). Multivariate and receiver operator characteristic analyses revealed higher RIG-I/Cardif ratio, ISG15, and USP18 predicted NVR. Lower Cardif in NVR was confirmed by its protein level in Western blot. Also, transcriptional responses in peripheral blood mononuclear cells to the therapy were rapid and strong except for Cardif in not only a positive (RIG-I, ISG15, and USP18) but also in a negative regulatory manner (RNF125). NVR may have adopted a different equilibrium in their innate immune response. High RIG-I/Cardif and RIG-I/RNF125 ratios and ISG15 and USP18 are useful in identifying NVR.
    Gastroenterology 06/2008; 134(5):1396-405. · 11.68 Impact Factor
  • Article: The presence of steatosis and elevation of alanine aminotransferase levels are associated with fibrosis progression in chronic hepatitis C with non-response to interferon therapy.
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    ABSTRACT: Interferon (IFN) therapy leads to regression of hepatic fibrosis in chronic hepatitis C patients who achieve a sustained virologic response (SVR), while the beneficial effect is limited in those who fail to do so. The aim of the present study was to define factors associated with progression of fibrosis in patients who do not achieve a SVR. Fibrosis staging scores were compared between paired liver biopsies before and after IFN in 97 chronic hepatitis C patients who failed therapy. The mean interval between biopsies was 5.9 years. Factors associated with progression of fibrosis were analyzed. Fibrosis progressed in 23%, remained unchanged in 47% and regressed in 29%. Steatosis and a high average alanine aminotransferase (ALT) between biopsies were independent factors for progression of fibrosis with risk ratios of 5.53 and 4.48, respectively. Incidence and yearly rate of progression of fibrosis was 64% and 0.22+/-0.29 fibrosis units per year in those with both risk factors compared to 8% and -0.04+/-0.17 fibrosis units per year in those negative for both factors. Hepatic steatosis and elevated ALT levels are risk factors for progression of fibrosis in chronic hepatitis C patients who fail to achieve a SVR to IFN therapy and therefore may be therapeutic targets to halt the potentially progressive disease.
    Journal of Hepatology 06/2008; 48(5):736-42. · 9.26 Impact Factor