Kosei Hamano

Mutations in the NS5B region of the hepatitis C virus genome correlate with clinical outcomes of interferon-alpha plus ribavirin combination therapy

Background and Aim:  Combination treatments of interferon‐alpha (IFN) and ribavirin (RBV) are more effective than those of IFN alone in hepatitis C virus (HCV) infection. However, mechanisms of the action of the combination regimen are not well understood. To elucidate the viral genetic basis of IFN plus RBV combination therapy, genetic variabilities of HCV‐1b were analyzed.

Assessment of Kupffer cells by ferumoxides-enhanced MR imaging is beneficial for diagnosis of hepatocellular carcinoma: comparison of pathological diagnosis and perfusion patterns assessed by CT hepatic arteriography and CT arterioportography

To investigate the clinical significance of the radiographic assessment of Kupffer cells and hemodynamics in the diagnosis of hepatocellular nodules, both magnetic resonance (MR) imaging enhanced by ferumoxides and CT hepatic arteriography (CTHA)/CT arterioportography (CTAP) were undertaken for 118 patients with 158 primary nodular hepatocellular lesions. The radiographic findings were analyzed in the context of the pathological diagnosis. Among nodules presumed to be pre- or early HCC by CTHA/CTAP, all 13 hyperintense nodules identified by MR imaging (MRI) were found pathologically to be hepatocellular carcinoma (HCC). In contrast, in 14 hypointense nodules, no advanced (moderately or poorly differentiated) HCC was pathologically identified and none of these progressed to advanced HCC during the follow up period (mean: 24 months). Instead, 78% of these cases were pathologically confirmed as dysplastic nodules. For the 16 lesions undetectable by CTHA/CTAP, four of eight (50%) hypointense nodules turned out to be dysplastic nodules and one hyperintense lesion was HCC. Signal intensity by ferumoxides-enhanced MRI showed a strong correlation with the increase or decrease of Kupffer cells assessed by immunohistochemistry. Assessment of Kupffer cells by ferumoxides-enhanced MRI is beneficial for the accurate diagnosis of primary hepatocellular nodules that are considered borderline or early stage HCC by their hemodynamic profile.

Interferon-stimulated gene expression and hepatitis C viral dynamics during different interferon regimens

BACKGROUND/AIMS To address the molecular mechanism for enhanced antiviral efficacy associated with a frequent dosing of interferon (IFN)-beta. METHODS Serum hepatitis C viral (HCV) dynamics, double-stranded RNA-activated protein kinase (PKR) mRNA and MxA mRNA levels in peripheral blood mononuclear cells (PBMC) were analyzed serially in 140 patients who were randomly assigned to a twice daily (3 MU bid) or once daily (6 MU qd) administration group. RESULTS In twice daily group, the rate of HCV decline during the second phase was 2-fold greater than in the once daily group (P=0.04). Peak PKR and MxA gene expression levels in the first phase (observed 4 h after a single administration) were 2-fold higher in the once daily group. However, the expression in the second phase was maintained at a significantly higher level in the twice daily group. Initial and peak expression levels were related to initial viral load. Basal expressions in PBMC were significantly correlated with those in the liver tissue (PKR, r=0.81; MxA, r=0.75, respectively, P<0.0001). CONCLUSIONS Our data suggest that elimination of HCV-infected cells is enhanced by twice daily dosing of IFN-beta, and that this enhanced effect is associated with a higher intracellular expression of PKR and MxA during the second phase.

Core promoter/pre-core mutations are associated with lamivudine-induced HBeAg loss in chronic hepatitis B with genotype C

BACKGROUND/AIMS To clarify the factors associated with the efficacy of lamivudine. METHODS Variables including basic core promoter (BCP) and pre-core (PreC) mutations were evaluated in 60 chronic hepatitis B e antigen (HBeAg)-positive patients with genotype C. Thirty patients were treated with lamivudine and the remaining 30 patients were age- and sex-matched controls. RESULTS Severe fibrosis was significantly more frequent in patients with the BCP-mutant/PreC-wild (MW) and BCP-mutant/PreC-mutant (MM) patterns compared to BCP-wild/PreC-wild (WW) pattern (P=0.02). The cumulative rates of HBeAg loss at 6, 12 and 18 months were significantly higher in the lamivudine group (14.2, 36.3, and 60.9%) compared with the control group (17.6, 17.6, and 24.5%, P=0.03), and was especially pronounced in patients with the MW pattern (P=0.04). The rate of lamivudine-related HBeAg loss was significantly lower in patients with the WW pattern (P=0.03). Factors correlating with HBeAg loss were histological fibrosis and activity, hepatitis B virus-DNA levels, BCP/PreC mutation and lamivudine therapy. Multivariate analysis revealed BCP/PreC mutations and fibrosis were independent factors for HBeAg loss. CONCLUSIONS With specific reference to the genotype C, we found earlier HBeAg loss was expected in patients carrying MM and MW patterns, while the efficacy of lamivudine was limited in patients with the WW pattern.

Sequence elements correlating with circulating viral load in genotype 1b hepatitis C virus infection

The correlation between hepatitis C virus (HCV) genomic sequences and circulating HCV RNA levels was assessed to investigate the genetic elements affecting viral load. The interferon sensitivity-determining region (ISDR) sequence and the serum viral load were strongly correlated in 226 patients examined. Analysis of the entire HCV genome from six patients (three with a high and the others with a low viral load) with similar ISDR sequences identified several candidate residues associated with viral load. The amino acid (aa) sequences of these candidate residues and flanking regions in 67 additional patients revealed that only the residue at aa 962 varied significantly between the HCV patients with low and high serum loads (P=0.042). At this position, alanine was observed more frequently in the patients with a high viral load. In conclusion, our results strongly suggest that serum HCV RNA loads are inversely correlated with amino acid substitutions in the ISDR, and aa 962 was identified as a possible second determinant of serum HCV RNA load.

A case of primary leiomyoma of the liver in a patient without evidence of immunosuppression.

A 31-year-old Japanese male was admitted to our hospital for investigation of an asymptomatic nodular lesion of the liver detected by abdominal ultrasonography (US) during a routine medical examination. Computed tomography (CT) revealed a single, hypovascular mass 35 mm in diameter, within the left lobe of the liver. The tumor demonstrated hypointensity on T1-weighted, and hyperintensity on T2-weighted magnetic resonance (MR) imaging. Hematological and biochemical investigations were normal. There were no abnormalities of the gastrointestinal or urinary tracts. A left lateral segmentectomy of the liver was performed. Pathological examination of the nodule revealed a primary leiomyoma of the liver, with positive immunohistochemical staining for vimentin and desmin antigens. Primary leiomyoma of the liver is rare, with the majority of cases associated with immunodeficiency disorders. This patient had no evidence of any underlying disease. Primary leiomyoma of the liver should be considered when a nodular lesion is found in a patient without evidence of viral hepatitis.

Viral load change and sequential evolution of entire hepatitis C virus genome in Irish recipients of single source-contaminated anti-D immunoglobulin*

Summary.  In hepatitis C virus (HCV) infection, serum viral load is important in the prediction of therapeutic efficacy. However, factors that affect the viral load remain poorly understood. To identify viral genomic elements responsible for the viral load, we investigated samples from a population of Irish women who were iatrogenically infected from a single HCV source by administration of HCV 1b‐contaminated anti‐D immune globulin between 1977 and 1978 (Kenny‐Walsh, N Engl J Med 1999; 340: 1228). About 15 patients were divided into two groups, viral load increasing group (11 patients) and decreasing group (4 patients). Pairs of sera were collected from each patient at interval between 1.1 and 5.8 years. Full‐length sequences of HCV genome were determined, and analyzed for changes in each patient. Sliding window analysis showed that the decreasing group had significantly higher mutation rates in a short segment of NS5B region that may affect the activity of RNA‐dependent RNA polymerase. By comparing each coding regions, significantly higher mutation numbers were accumulated in NS5A region in the increasing group than the decreasing group (0.92 vs 0.16 nucleotides/site/year, P = 0.021). The mutation in certain positions of the HCV genome may be determinant factors of the viral load in a relatively homogeneous patient population.

Laparoscopic ablation therapy for hepatocellular carcinoma. Clinical significance of a newly developed laparoscopic sector ultrasonic probe

Background:  Although a laparoscopic approach for local ablation plays an important role in treating hepatocellular carcinoma (HCC) near the liver surface, precise targeting ablation has been difficult using a conventional linear ultrasonic probe. We have recently developed a sector ultrasonic probe with a guiding tract for precisely targeting tumors.