Biomedical subjects
Publications and source records attributed to Kyuichi Tanikawa.
Oxidative stress has recently been shown to play an important role in various liver diseases. Therefore, further studies on oxidative stress in liver diseases are urgently required. In this review, oxidative stress is discussed from the aspects of molecular morphology, metabolism, and aging.
A retrospective survey of Japanese patients histologically diagnosed with chronic hepatitis B was conducted to determine the effectiveness of lamivudine in preventing hepatocellular carcinoma (HCC). Of the 2795 patients who satisfied criteria for analysis after treatment from any of 30 medical institutions, 657 had received lamivudine and the remaining 2138 had not. A Cox regression model with liver biopsy as the starting point revealed seven factors related to HCC: lamivudine therapy, gender, family clustering of hepatitis B, age at liver biopsy, hepatic fibrosis stage, serum albumin level, and platelet count. In a matched case-controlled study, 377 patients in a lamivudine-treated group and 377 matched patients in a non-treated group were selected based on their propensity scores. The mean follow-up period was 2.7 years in the lamivudine group and 5.3 years in the control group. In the lamivudine group, HCC occurred in four patients (1.1%) with an annual incidence rate of 0.4%/(patient/year), whereas in the control group HCC occurred in 50 patients (13.3%) for a rate of 2.5%/(patient/year). A comparison of the cumulative HCC incidence between the two groups by the Kaplan-Meier method showed a significantly lower incidence of HCC in the lamivudine group (p<0.001). These findings suggest that lamivudine effectively reduces the incidence of HCC in patients with chronic hepatitis B.
The possibility of delaying progression to hepatocellular carcinoma in chronic hepatitis C patients with genotype 1 and high viral titers with baseline ALT levels of >/=50IU/L was examined by administration of IFN plus ribavirin combination therapy using ALT normalization as index and IFN monotherapy as control. The rate of sustained ALT normalization (ALT normal at 24 weeks after the end of treatment) was 28.1% with combination therapy and 10.5% with IFN monotherapy (P=0.001). Furthermore, the number of patients with sustained viral response (SVR) and with sustained ALT normalization in non-SVR patients was also significantly higher in the combination therapy versus monotherapy group. Mean ALT values during treatment and for 6 months after the end of treatment were significantly lower with combination therapy versus monotherapy even in virological nonresponders, as well as significantly lower during the post-treatment observation period in patients who relapsed after the end of treatment. Since increase in the rate of sustained ALT normalization and SVR were successfully achieved, inhibition of progression to hepatocellular carcinoma should be studied with long-term IFN and ribavirin combination therapy.
Data on 334 patients with HCV genotype 1b and high viral levels were extracted from two multicenter double-blind studies conducted in Japan comparing IFN alpha-2b plus ribavirin (n = 209) with IFN alpha-2b alone (n = 125) for 24 weeks. HCV RNA assay was conducted before and 4, 12, and 24 weeks after the start and 4, 12, and 24 weeks after the end of treatment. Both sustained viral response (SVR) rate and relapse rate after the end of treatment were analyzed in relation to baseline viral levels and the time of first disappearance of virus. In the combination treatment group, the percentage of patients who were HCV RNA-negative within 4 weeks decreased with increase in baseline viral levels (i.e. 42%, 15%, and 11% were HCV RNA-negative in the groups exhibiting <500, 500 to <850, and >/=850kcopies/mL, respectively). In the IFN monotherapy group, the response rates were lower at 13%, 15%, and 1%, respectively. Disappearance of virus within 12 weeks after the start of combination treatment was indicative of higher probability of SVR. The risk of relapse was more highly correlated with the timing of initial viral disappearance than with baseline HCV levels; it was 4.8 and 10.3 times higher in patients who became HCV-negative at 4-12 and 13-24 weeks compared with in those who were HCV-negative within 4 weeks.
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BACKGROUND: Few comprehensive reviews on the pathogenesis of hepatitis C virus (HCV)-related liver diseases have been presented to the present. This article was to review the pathogenesis and treatment of HCV-related liver diseases. DATA SOURCES: Data presented here are mostly taken from Japanese studies. RESULTS: HCV infection is characterized by persistent inflammation of the liver and frequent development of hepatocellular carcinoma (HCC) in most cases. These characteristic evidences could be explained by immunological alterations and oxidative stress in the hepatocyte caused by HCV infection. Interferon (IFN) treatment is carried out, at present, not only for the elimination of infected HCV for the treatment of chronic liver diseases, but also for both the prevention of HCC and the treatment of advanced HCC with chemotherapy. The treatment for oxidative stress is also important for non-responders to IFN. CONCLUSION: It is important to understand the pathogenesis of HCV-related liver diseases for a successful treatment.
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An anti-diabetic agent, troglitazone, was withdrawn from the market because of its association with liver injury. However, the mechanism of the injury has not been elucidated. We examined, retrospectively, the frequency of the polymorphisms of the cytochrome P450 (CYP) 2C19 and 2D6 genes in eight patients with type 2 diabetes who had troglitazone-induced liver injury and 31 subjects who tolerated troglitazone well. Polymorphisms of CYP 2C19 and 2D6 genes were analyzed by polymerase chain reaction using peripheral white blood cells. The incidence of mutations was compared with known population data for the Japanese. Homozygous or compound heterozygous mutations in CYP 2C19 alleles were found in four of the eight (50.0%) patients with troglitazone-induced liver injury. This rate was significantly higher than that in patients without liver injury (four of 31, 12.9%). The frequency of P450 2D6 mutations was the same in both groups. In conclusion, troglitazone-induced liver injury occurred more frequently in subjects with the CYP 2C19 mutations in Japanese patients.
We treated a patient simultaneously infected with hepatitis E virus and Leptospira interrogans, both acquired in China. Severe hyperbilirubinemia required nearly 200 days to resolve, transminase elevation showed a fluctuating course, and liver biopsy specimens showed fibrosis unusual for hepatitis E. Leptospirosis appeared to have altered the course of hepatitis E virus infection in this patient, even though infection with Leptospira was cleared with antibiotics by 50 days after the onset of the hepatitis symptoms.
T-cell hyporesponsiveness may lead to chronicity of hepatitis C virus (HCV) infection. We evaluated whether interferon (IFN)-gamma injection can bring a Th1-dominant environment to patients with chronic hepatitis C. Seventeen patients with genotype 1b received natural IFN-alpha 5MU daily for the first 2 weeks and three times a week for the next 22 weeks followed by natural IFN-gamma 1 MU daily for 2 weeks. In 4 of 17 patients (23.5%), alanine aminotransferase (ALT) was normalized and 3 of these 4 patients (75.0%) cleared HCV RNA. beta2 microglobulin (BMG), neopterin and soluble (s) Fas increased with IFN-alpha and increased more with IFN-gamma. Serum interleukin (IL)-12, CD4 and CD8 remained unchanged with IFN-alpha but increased after IFN-alpha was replaced by IFN-gamma. IL-10 was not changed either with IFN-alpha or gamma. Productions of IL-2, IFN-gamma and tumor necrosis factor (TNF)-alpha by peripheral blood mononuclear cells did not change by IFN-alpha therapy, however, they were enhanced at the end of IFN-gamma therapy. Productions of IL-2 and 4 were unaffected. These results show that some immune parameters become Th1-dominant by additional IFN-gamma in patients with chronic hepatitis C. Combination of these two IFNs should be explored.
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