Seitetsu Yoon

Comparative Sequence Analysis of the Core Protein and Its Frameshift Product, the F Protein, of Hepatitis C Virus Subtype 1b Strains Obtained from Patients with and without Hepatocellular Carcinoma

ABSTRACT The core protein of hepatitis C virus (HCV) has been implicated in hepatocarcinogenesis. In order to determine whether there is a correlation between mutations of the core protein and the development of hepatocellular carcinoma (HCC), the core protein-coding sequence of the viral genome of HCV subtype 1b (HCV-1b) obtained from patients with and without HCC was analyzed. We found that 12 (40.0%) of 30 HCV-1b isolates from patients with HCC but none of 29 isolates from patients without HCC had a point mutation(s) in an N-terminal region of 20 residues. Similarly, 10 (33.3%) of 30 isolates from patients with HCC had mutations in a limited region between residues 141 and 160, whereas only 2 (6.9%) of 29 isolates from patients without HCC did. The differences between the two groups were statistically significant. The mutations were found in isolates from both cancerous and adjacent noncancerous tissues of patients with HCC, suggesting that the mutations were present before the development of HCC. The other regions of the core protein of some isolates also had mutations, but no significant difference was observed between isolates from patients with HCC and those from patients without HCC. The F protein, a frameshift product that is still hypothetical for HCV-1b strains, showed more sequence diversity than the core protein among the isolates analyzed, but there were no significant differences in the mutation rates or positions between isolates from patients with HCC and isolates from patients without HCC, except for a short N-terminal sequence of ∼11 residues that is shared with the core protein.

Clinical significance of serum hyaluronic acid as a fibrosis marker in chronic hepatitis C patients treated with interferon‐α: Histological evaluation by a modified histological activity index scoring system

Abstract The aim of the present study was to investigate the histological changes effected by interferon (IFN) treatment and to evaluate the clinical significance of serum hyaluronic acid (HA) as a marker of fibrosis. Forty‐nine patients with chronic hepatitis C treated with IFN‐α were divided into three groups according to the existence of viraemia: sustained complete responders (CR), complete responders with relapse (PR) and non‐responders (NR). Needle biopsy sections of the liver taken before and at the end of IFN treatment were assessed according to the modified histological activitindex (HAI) scoring system. Serum fibrosis markers, including HA, were measured at needle biopsies. Biopsies of CR at the end of treatment showed a significant improvement in fibrosis and necroinflammatory scores. More significant correlation was observed between fibrosis scores and serum levels of HA before IFN treatment (r= 0.607, P < 0.0001) than those between fibrosis scores, on the one hand, and pepride of type III procollagen (PIIIP; r= 0.531, P= 0.0004) or type IV collagen 7S domain (type IV‐C; r= 0.241, P= 0.1062) on the other. Moreover, serum HA levels fell significantly in patients in whom fibrosis improved (P= 0.011). This is the first paper describing the advantages of the modified HAI scoring system over others in estimating the effect of IFN‐α; the results also indicate that serum HA can be useful in monitoring liver fibrosis in chronic hepatitis C patients treated with IFN‐α.

Identification of Hepatitis C Virus (HCV) Subtype 1b Strains That Are Highly, or Only Weakly, Associated with Hepatocellular Carcinoma on the Basis of the Secondary Structure of an Amino-Terminal Portion of the HCV NS3 Protein

ABSTRACT The NS3 protein of hepatitis C virus subtype 1b (HCV-1b) isolates obtained from 89 patients with hepatocellular carcinoma (HCC) and 78 patients without HCC were analyzed. On the basis of the secondary structure of the amino-terminal 120 residues of NS3, HCV-1b isolates were classified into group A, group B, and an indeterminate group, each of which was further divided into a number of subgroups, such as A1-1, A1-2, A2-1, A2-2, B1-1, B1-2, B2-1, B2-2, C-1, C-2, and C-3. HCV-1b isolates of subgroup B1-1 were found in 53 (59.6%) of 89 patients with HCC and 19 (24.4%) of 78 patients without HCC, with the difference between the two patient groups being statistically significant (P < 0.00001). Although the number of isolates was small, subgroup B2-1 was also highly associated with HCC, with all five isolates in that subgroup being found in patients with HCC (P < 0.05). On the other hand, HCV-1b isolates of subgroup A1-1 were associated only weakly with HCC; they were found in 6 (6.7%) of 89 patients with HCC and in 25 (32.1%) of 78 patients without HCC, with the difference between the two patient groups being statistically significant (P < 0.0001). The other subgroups, such as A1-2, A2-1, B1-2, C-1, C-2, and C-3, were moderately associated with HCC; their distribution patterns among patients with HCC did not differ significantly from those among patients without HCC. Taken together, our results suggest that HCV-1b isolates of subgroups B1-1 and B2-1 are highly associated with HCC and that this secondary structure analysis may be useful for predicting the relative risk of developing HCC.

Significance of Serum Matrix Metalloproteinases and Their Inhibitors on the Antifibrogenetic Effect of Interferon-Alfa in Chronic Hepatitis C Patients

Objective and Methods: The imbalance between matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMPs) is considered to be an important determination of deposition and breakdown of the extracellular matrix. To investigate the antifibrogenetic effect of interferon-α (IFN-α) treatment on factors regulating hepatic fibrosis, serum MMP-1, MMP-2, TIMP-1 and TIMP-2 levels were measured by the one-step sandwich enzyme immunoassay in 27 patients with chronic hepatitis C and compared with the histological status of the patients before and at the end of treatment. Results: After 6 months of IFN-α treatment, the histological status of liver fibrosis showed improvement in 9 patients (IF group) and no change or a worsening in 18 patients (NIF group). Compared with pretreatment levels, in the IF group, IFN treatment caused a significant increase in the MMP-1/TIMP-1 ratio. In the NIF group, however, the MMP-1/TIMP-1 ratio tended towards a decrease; moreover, there was not only a significant increase in TIMP-2 levels but also a tendency towards an increase in TIMP-1 levels. Conclusion: These results suggested that an elevated MMP-1/TIMP-1 ratio may ameliorate liver fibrosis by interferon in cases of chronic hepatitis C, whereas elevated levels of TIMP-1 and TIMP-2 might impede improvement.

Downregulation of stomach cancer-associated protein tyrosine phosphatase-1 (SAP-1) in advanced human hepatocellular carcinoma.

SAP-1 (stomach cancer-associated protein tyrosine phosphatase-1) is a transmembrane-type protein tyrosine phosphatase that has been implicated as a negative regulator of integrin-mediated signaling. The potential role of this enzyme in hepatocarcinogenesis has now been investigated by examining its expression in 32 surgically excised human hepatocellular carcinoma (HCC) specimens. Both immunohistochemical and immunoblot analyses revealed that normal liver tissue, as well as tissue affected by chronic hepatitis or cirrhosis, contained substantial amounts of SAP-1. The expression level of SAP-1 in 75% of well-differentiated HCCs was similar to or higher than that observed in the surrounding noncancerous tissue. In contrast, the abundance of SAP-1 in 85.7% of moderately differentiated HCCs and in all poorly differentiated HCCs was greatly reduced compared with that in the adjacent tissue. Indeed, SAP-1 was almost undetectable in 83.3% of poorly differentiated HCCs. Furthermore, expression of recombinant SAP-1 in two highly motile human HCC cell lines resulted in a change in morphology and a marked reduction in both migratory activity and growth rate. In conclusion, these results indicate that SAP-1 expression is downregulated during the dedifferentiation of human HCC, and that this downregulation may play a causal role in disease progression.

Sequence Heterogeneity in NS5A of Hepatitis C Virus Genotypes 2a and 2b and Clinical Outcome of Pegylated-Interferon/Ribavirin Therapy

Pegylated-interferon plus ribavirin (PEG-IFN/RBV) therapy is a current standard treatment for chronic hepatitis C. We previously reported that the viral sequence heterogeneity of part of NS5A, referred to as the IFN/RBV resistance-determining region (IRRDR), and a mutation at position 70 of the core protein of hepatitis C virus genotype 1b (HCV-1b) are significantly correlated with the outcome of PEG-IFN/RBV treatment. Here, we aimed to investigate the impact of viral genetic variations within the NS5A and core regions of other genotypes, HCV-2a and HCV-2b, on PEG-IFN/RBV treatment outcome. Pretreatment sequences of NS5A and core regions were analyzed in 112 patients infected with HCV-2a or HCV-2b, who were treated with PEG-IFN/RBV for 24 weeks and followed up for another 24 weeks. The results demonstrated that HCV-2a isolates with 4 or more mutations in IRRDR (IRRDR[2a]≥4) was significantly associated with rapid virological response at week 4 (RVR) and sustained virological response (SVR). Also, another region of NS5A that corresponds to part of the IFN sensitivity-determining region (ISDR) plus its carboxy-flanking region, which we referred to as ISDR/+C[2a], was significantly associated with SVR in patients infected with HCV-2a. Multivariate analysis revealed that IRRDR[2a]≥4 was the only independent predictive factor for SVR. As for HCV-2b infection, an N-terminal half of IRRDR having two or more mutations (IRRDR[2b]/N≥2) was significantly associated with RVR, but not with SVR. No significant correlation was observed between core protein polymorphism and PEG-IFN/RBV treatment outcome in HCV-2a or HCV-2b infection. Conclusion: The present results suggest that sequence heterogeneity of NS5A of HCV-2a (IRRDR[2a]≥4 and ISDR/+C[2a]), and that of HCV-2b (IRRDR[2b]/N≥2) to a lesser extent, is involved in determining the viral sensitivity to PEG-IFN/RBV therapy.

Correlation between Secondary Structure of an Amino-Terminal Portion of the Nonstructural Protein 3 (NS3) of Hepatitis C Virus and Development of Hepatocellular Carcinoma

Correlation between sequence variation of hepatitis C virus (HCV) and development of hepatocellular carcinoma (HCC) has not yet been demonstrated. In the present study, we analyzed sequence diversity of the NS3 protein of HCV and its possible correlation with HCC. On the basis of secondary structure of an amino‐terminal portion of NS3, HCV subtype 1b (HCV‐1b) isolates were classified into two groups, A and B. Group A isolates were found in 4 (11%) of 36 patients with HCC, and 22 (63%) of 35 patients without HCC. On the other hand, group B isolates were found in 32 (89%) of 36 patients with HCC, and 12 (34%) of 35 patients without HCC. The distribution patterns of those groups were significantly different between patients with and without HCC (P<0.001). HCV isolates of group B were found in both tumor and adjacent non‐tumor tissues obtained from patients with HCC, suggesting that the emergence of group B isolates was not a result of, but rather a possible causative factor for development of HCC. Taken together, our present results suggest that HCV‐1b strains of group B are highly associated with HCC and that the secondary structure analysis of NS3 would be useful to predict high risk for development of HCC in HCV‐1b‐infected patients.

Response to Interferon-α in Chronic Hepatitis B With and Without Precore Mutant Strain Detected by Mutation Site–specific Assay

Goals: We investigated whether the presence of precore mutant (stop codon mutation at codon 28) affects the response to interferon-α in patients with chronic hepatitis B. Background: Mutations of hepatitis B virus (HBV) may influence the response to treatment. The association of precore mutant with the response to interferon is controversial. Study: Thirty-one Japanese patients with hepatitis B e antigen–positive chronic hepatitis were treated with natural interferon-α. HBV DNA with the precore mutation was assayed in serum using a mutation site–specific assay before and after treatment. Results: Before treatment, precore mutant was detected in 22 cases (group A) and not detected in 9 cases (group B). Serum HBV DNA level before treatment was not different between the 2 groups. At the end of treatment, serum HBV DNA was decreased to undetectable levels in 13% (4 of 31). Six months after treatment, the percentage of cases with loss of hepatitis B e antigen and a decrease in the transaminase level to within the normal range was significantly higher in group B than in group A (67%, 18%, P = 0.015). Conclusions: Chronic hepatitis without precore mutant strain before treatment is more responsive to IFN-α.

Successful rescue of severe recurrent hepatitis C with interferon and ribavirin in a liver transplant patient

BACKGROUND Rapid graft dysfunction caused by hepatitis C virus (HCV) reinfection, although uncommon, is a disastrous complication in liver transplant patients. Finding an effective therapy for this subgroup of patients with severe recurrent HCV is a priority. METHOD We describe a successful rescue of a 46-year-old man with recurrent hepatitis C (HCV genotype 1b) using long-term interferon (IFN) and ribavirin. The patient had a very aggressive type of posttransplantation HCV infection, as judged by biochemical and histologic findings. RESULTS Despite high pretreatment values of serum alanine aminotransferase (ALT; peak value of 901 IU/L) and HCV-RNA (2.3 x 10(6) copies/ml), the combination therapy with IFN and ribavirin produced a rapid normalization of the serum ALT values, accompanied by the clearance of serum HCV-RNA. Although HCV-RNA reappeared in the serum at 3 months, the patient had continued ALT normalization and histological improvement with follow-up of over 26 months to date after the initiation of the combination therapy. CONCLUSION This observation suggests that IFN in combination with ribavirin may offer an effective therapeutic option for liver transplant patients with severe recurrent hepatitis C.

A case of acute pancreatitis complicating salmonella enteritis

SummaryWe report a case of acute pancreatitis complicating Salmonella enteritis. A 43-yr-old woman who was admitted to our department because of Salmonella enteritis developed clinical acute pancreatitis with laboratory and radiographic signs on the fourth hospital day. She was free from symptoms on the eighth hospital day, but her elevated serum amylase and lipase levels persisted for more than 2 mo. In this case, clinical acute pancreatitis was a complication of bacterial enteritis caused by Salmonella enteritidis, and it was characterized by onset a few days after the onset of enteritis and by sustained elevation of serum pancreatic enzyme levels.