Toshiji Saibara
Kōchi University
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Featured researches published by Toshiji Saibara.
Journal of Gastroenterology and Hepatology | 2007
Shivakumar Chitturi; Geoffrey C Farrell; Etsuko Hashimoto; Toshiji Saibara; George K. K. Lau; José D. Sollano
Non‐alcoholic fatty liver disease (NAFLD) is the most common liver disorder in Western industrialized countries, affecting 20–40% of the general population. Large population‐based surveys in China, Japan, and Korea indicate that the prevalence of NAFLD is now 12% to 24% in population subgroups, depending on age, gender, ethnicity, and location (urban versus rural). There is strong evidence that the prevalence of NAFLD has increased recently in parallel with regional trends in obesity, type 2 diabetes, and metabolic syndrome; and that further increases are likely. The relationship between NAFLD, central obesity, diabetes, and metabolic syndrome is clearly evident in retrospective and prospective Asian studies, but the strength of association with these metabolic risk factors is only appreciated when regional definitions of anthropometry are used. Pathological definition of NAFLD, particularly its activity and the extent of liver fibrosis, requires histological examination, but liver biopsy is often not appropriate in this disorder for logistic reasons. An alternative set of operational definitions is proposed here. Clinicians need guidelines as how best to diagnose and manage NAFLD and its associated metabolic disorders in countries with scant healthcare resources. The Asia–Pacific Working Party (APWP) for NAFLD was convened to collate evidence and deliberate these issues. Draft proposals were presented and discussed at Asia–Pacific Digestive Week at Cebu, Philippines, in late November 2006, and are published separately in this issue of the Journal as an Executive Summary. The present document reviews the reasoning and evidence behind the APWP‐NAFLD proposals for definition, assessment, and management of NAFLD in the Asia–Pacific region.
Clinical Gastroenterology and Hepatology | 2011
Kohichiroh Yasui; Etsuko Hashimoto; Yasuji Komorizono; Kazuhiko Koike; Shigeki Arii; Yasuharu Imai; Toshihide Shima; Yoshihiro Kanbara; Toshiji Saibara; Takahiro Mori; Sumio Kawata; Hirofumi Uto; Shiro Takami; Yoshio Sumida; Toshinari Takamura; Miwa Kawanaka; Takeshi Okanoue
BACKGROUND & AIMS Nonalcoholic steatohepatitis (NASH) can progress to hepatocellular carcinoma (HCC). We aimed to characterize the clinical features of NASH patients with HCC. METHODS In a cross-sectional multicenter study in Japan, we examined 87 patients (median age, 72 years; 62% male) with histologically proven NASH who developed HCC. The clinical data were collected at the time HCC was diagnosed. RESULTS Obesity (body mass index ≥25 kg/m(2)), diabetes, dyslipidemia, and hypertension were present in 54 (62%), 51 (59%), 24 (28%), and 47 (55%) patients, respectively. In nontumor liver tissues, the degree of fibrosis was stage 1 in 10 patients (11%), stage 2 in 15 (17%), stage 3 in 18 (21%), and stage 4 (ie, liver cirrhosis) in 44 (51%). The prevalence of cirrhosis was significantly lower among male patients (21 of 54, 39%) compared with female patients (23 of 33, 70%) (P = .008). CONCLUSIONS Most patients with NASH who develop HCC are men; the patients have high rates of obesity, diabetes, and hypertension. Male patients appear to develop HCC at a less advanced stage of liver fibrosis than female patients.
Journal of Clinical Investigation | 2000
Yoshihisa Nemoto; Katsumi Toda; Masafumi Ono; Kiyomi Fujikawa-Adachi; Toshiji Saibara; Saburo Onishi; Hideaki Enzan; Teruhiko Okada; Yutaka Shizuta
Hepatic steatosis is a frequent complication in nonobese patients with breast cancer treated with tamoxifen, a potent antagonist of estrogen. In addition, hepatic steatosis became evident spontaneously in the aromatase-deficient (ArKO) mouse, which lacks intrinsic estrogen production. These clinical and laboratory observations suggest that estrogen helps to maintain constitutive lipid metabolism. To clarify this hypothesis, we characterized the expression and activity in ArKO mouse liver of enzymes involved in peroxisomal and mitochondrial fatty acid beta-oxidation. Northern analysis showed reduced expression of mRNAs for very long fatty acyl-CoA synthetase, peroxisomal fatty acyl-CoA oxidase, and medium-chain acyl-CoA dehydrogenase, enzymes required in fatty acid beta-oxidation. In vitro assays of fatty acid beta-oxidation activity using very long (C24:0), long (C16:0), or medium (C12:0) chain fatty acids as the substrates confirmed that the corresponding activities are also diminished. Impaired gene expression and enzyme activities of fatty acid beta-oxidation were restored to the wild-type levels, and hepatic steatosis was substantially diminished in animals treated with 17beta-estradiol. Wild-type and ArKO mice showed no difference in the binding activities of the hepatic nuclear extracts to a peroxisome proliferator response element. These findings demonstrate the pivotal role of estrogen in supporting constitutive hepatic expression of genes involved in lipid beta-oxidation and in maintaining hepatic lipid homeostasis.
Journal of Gastroenterology and Hepatology | 2007
Jian-Gao Fan; Toshiji Saibara; Shivakumar Chitturi; Byong Ik Kim; Joseph J.Y. Sung; A Chutaputti
The risk factors and settings for non‐alcoholic fatty liver disease (NAFLD) in Asians are reviewed comprehensively. Based particularly on large community‐based studies using ultrasonography, case–control series and prospective longitudinal studies, the prevalence of NAFLD in Asia is between 12% and 24%, depending on age, gender, locality and ethnicity. Further, the prevalence in China and Japan has nearly doubled in the last 10–15 years. A detailed analysis of these data shows that NAFLD risk factors for Asians resemble those in the West for age at presentation, prevalence of type 2 diabetes mellitus (T2DM) and hyperlipidemia. The apparent differences in prevalence of central obesity and overall obesity are related to criteria used to define waist circumference and body mass index (BMI), respectively. The strongest associations are with components of the metabolic syndrome, particularly the combined presence of central obesity and obesity. Non‐alcoholic fatty liver disease appears to be associated with long‐standing insulin resistance and likely represents the hepatic manifestation of metabolic syndrome. Not surprisingly therefore, Asians with NAFLD are at high risk of developing diabetes and cardiovascular disease. Conversely, metabolic syndrome may precede the diagnosis of NAFLD. The increasing prevalence of obesity, coupled with T2DM, dyslipidemia, hypertension and ultimately metabolic syndrome puts more than half the worlds population at risk of developing NAFLD/non‐alcoholic steatohepatitis/cirrhosis in the coming decades. Public health initiatives are clearly imperative to halt or reverse the global ‘diabesity’ pandemic, the underlying basis of NAFLD and metabolic syndrome. In addition, a perspective of NAFLD beyond its hepatic consequences is now warranted; this needs to be considered in relation to management guidelines for affected individuals.
Hepatology | 2007
Akira Hirose; Masafumi Ono; Toshiji Saibara; Yasuko Nozaki; Kosei Masuda; Akemi Yoshioka; Masaya Takahashi; Naoaki Akisawa; Shinji Iwasaki; Jude A. Oben; Saburo Onishi
Nonalcoholic steatohepatitis (NASH) is now the most frequent cause of chronic liver impairment in developed countries and is a suggested causative factor in the development of cryptogenic cirrhosis and hepatocellular carcinoma. At present there is no effective and accepted therapy for NASH. The renin‐angiotensin system is involved in hepatic fibrosis through activation of hepatic stellate cells, major fibrogenic cells in the liver. Hepatic stellate cells are activated by liver injury to express excessive matrix proteins and profibrogenic cytokines such as transforming growth factor–beta 1. Medicines that inhibit this pathway may be of therapeutic potential in NASH. Using a methionine‐choline–deficient rat model of NASH, we studied the potential utility of an angiotensin II type 1 receptor blocker (ARB), olmesartan, on biochemical, histologic, and antioxidant measures of disease activity. ARB significantly attenuated increases in aspartate aminotransferase, activation of hepatic stellate cells, oxidative stress, expression of transforming growth factor–beta 1, expression of collagen genes, and liver fibrosis. Conclusion: Our observations strongly suggest a potential preventive role for ARB in the progression of nonalcoholic steatohepatitis. (HEPATOLOGY 2007.)
PLOS ONE | 2012
Takahisa Kawaguchi; Yoshio Sumida; Atsushi Umemura; Keitaro Matsuo; Meiko Takahashi; Toshinari Takamura; Kohichiroh Yasui; Toshiji Saibara; Etsuko Hashimoto; Miwa Kawanaka; Sumio Watanabe; Sumio Kawata; Yasuharu Imai; Miki Kokubo; Toshihide Shima; Hyohun Park; Hideo Tanaka; Kazuo Tajima; Ryo Yamada; Fumihiko Matsuda
Background Nonalcoholic fatty liver disease (NAFLD) includes a broad range of liver pathologies from simple steatosis to cirrhosis and fibrosis, in which a subtype accompanying hepatocyte degeneration and fibrosis is classified as nonalcoholic steatohepatitis (NASH). NASH accounts for approximately 10–30% of NAFLD and causes a higher frequency of liver-related death, and its progression of NASH has been considered to be complex involving multiple genetic factors interacting with the environment and lifestyle. Principal Findings To identify genetic factors related to NAFLD in the Japanese, we performed a genome-wide association study recruiting 529 histologically diagnosed NAFLD patients and 932 population controls. A significant association was observed for a cluster of SNPs in PNPLA3 on chromosome 22q13 with the strongest p-value of 1.4×10−10 (OR = 1.66, 95%CI: 1.43–1.94) for rs738409. Rs738409 also showed the strongest association (p = 3.6×10−6) with the histological classifications proposed by Matteoni and colleagues based on the degree of inflammation, ballooning degeneration, fibrosis and Mallory-Denk body. In addition, there were marked differences in rs738409 genotype distributions between type4 subgroup corresponding to NASH and the other three subgroups (p = 4.8×10−6, OR = 1.96, 95%CI: 1.47–2.62). Moreover, a subgroup analysis of NAFLD patients against controls showed a significant association of rs738409 with type4 (p = 1.7×10−16, OR = 2.18, 95%CI: 1.81–2.63) whereas no association was obtained for type1 to type3 (p = 0.41). Rs738409 also showed strong associations with three clinical traits related to the prognosis of NAFLD, namely, levels of hyaluronic acid (p = 4.6×10−4), HbA1c (p = 0.0011) and iron deposition in the liver (p = 5.6×10−4). Conclusions With these results we clearly demonstrated that Matteoni type4 NAFLD is both a genetically and clinically different subset from the other spectrums of the disease and that the PNPLA3 gene is strongly associated with the progression of NASH in Japanese population.
Virchows Archiv | 1994
Hideaki Enzan; H. Hara; H. Himeno; S. Iwamura; Toshiji Saibara; Saburo Onishi; Y. Yamamoto
To identify Ito cells in normal and pathological adult human livers, immunohistochemical studies were performed by the avidin-biotin-peroxidase complex method using monoclonal antibodies for α-smooth muscle actin (ASMA), desmin, and vimentin. Fifty one needle biopsies, 7 surgically resected specimens, and 5 autopsy specimens were studied. In the normal adult liver vascular smooth muscle cells and pericytes, together with perisinusoidal cells with thin cytoplasmic processes were positive for ASMA. These latter cells formed a loose and discontinuous layer along the sinusoidal walls. Immunoelectron microscopy showed that the ASMA-positive perisinusoidal cells were Ito cells containing fat droplets. The other sinusoidal lining cells were negative for ASMA. In chronic liver disease, ASMA-positive Ito cells showed an increase in number, size, and the intensity of immunostaining in areas of piecemeal necrosis), and formed a continuous cellular network. These cells were dendritic in shape with irregularly elongated cytoplasmic processes and contained an increased amount of microfilaments, in association with loss of the characteristic fat droplets. Thus, their ultrastructural features corresponded to those of myofibroblastic cells. Ito cells showed no staining for desmin in both normal and pathological livers. These results indicate that immunohistochemistry using an anti-ASMA antibody is a sensitive and reliable method for the identification of both normal and transformed Ito cells in adult human livers.
BMC Gastroenterology | 2012
Yoshio Sumida; Masato Yoneda; Hideyuki Hyogo; Yoshito Itoh; Masafumi Ono; Hideki Fujii; Yuichiro Eguchi; Yasuaki Suzuki; Noriaki Aoki; Kazuyuki Kanemasa; Koji Fujita; Kazuaki Chayama; Toshiji Saibara; Norifumi Kawada; Kazuma Fujimoto; Yutaka Kohgo; Toshikazu Yoshikawa; Takeshi Okanoue
BackgroundA reliable and inexpensive noninvasive marker of hepatic fibrosis is required in patients with nonalcoholic fatty liver disease (NAFLD). FIB4 index (based on age, aspartate aminotransferase [AST] and alanine aminotransferase [ALT] levels, and platelet counts) is expected to be useful for evaluating hepatic fibrosis. We validated the performance of FIB4 index in a Japanese cohort with NAFLD.MethodsThe areas under the receiver operating characteristic curves (AUROC) for FIB4 and six other markers were compared, based on data from 576 biopsy-proven NAFLD patients. Advanced fibrosis was defined as stage 3-4 fibrosis. FIB4 index was assessed as: age (yr) × AST (IU/L)/(platelet count (109/L) × √ALT (IU/L))ResultsAdvanced fibrosis was found in 64 (11%) patients. The AUROC for FIB4 index was superior to those for the other scoring systems for differentiating between advanced and mild fibrosis. Only 6 of 308 patients with a FIB4 index below the proposed low cut-off point (< 1.45) were under-staged, giving a high negative predictive value of 98%. Twenty-eight of 59 patients with a FIB4 index above the high cut-off point (> 3.25) were over-staged, giving a low positive predictive value of 53%. Using these cutoffs, 91% of the 395 patients with FIB-4 values outside 1.45-3.25 would be correctly classified. Implementation of the FIB4 index in the Japanese population would avoid 58% of liver biopsies.ConclusionThe FIB4 index was superior to other tested noninvasive markers of fibrosis in Japanese patients with NAFLD, with a high negative predictive value for excluding advanced fibrosis. The small number of cases of advanced fibrosis in this cohort meant that this study had limited power for validating the high cut-off point.
Journal of Hepatology | 1994
Saburo Onishi; Tateo Sakamaki; Takashi Maeda; Shinichi Iwamura; Akira Tomita; Toshiji Saibara; Yasutake Yamamoto
The association between human leukocyte antigens and primary biliary cirrhosis is controversial, but major histocompatibility complex class II antigen DR8 was recently reported to be associated with increased susceptibility for primary biliary cirrhosis in some Caucasians and Japanese. Accordingly, we performed DNA typing of HLA class II genes in Japanese patients with primary biliary cirrhosis. The genotypes of HLA DRB1, DRB3-5, DQA and DQB were determined by polymerase chain reaction and subsequent hybridization with sequence specific oligonucleotides in 31 primary biliary cirrhosis patients and 215 racially matched local controls. DR8 was found in 24 of the 31 primary biliary cirrhosis patients and was highly concentrated in DRB1*0803. The gene frequency of DRB1*0803 was significantly increased in the patients (35.5% vs 7.4%, relative risk = 6.84, p < 0.0001). DQA1*0103 and DQB1*0601 were also increased in the primary biliary cirrhosis patients, in relation to linkage disequilibrium with DRB1*0803 on the same haplotype. In contrast, DQA1*0102 showed a significantly lower frequency in the primary biliary cirrhosis patients (p < 0.05). These data suggest that DRB1*0803 is one of the HLA class II genes related to an increased risk of primary biliary cirrhosis in Japanese individuals.
Microscopy Research and Technique | 1997
Hideaki Enzan; Hiromi Himeno; Makoto Hiroi; Hiroshi Kiyoku; Toshiji Saibara; Saburo Onishi
To elucidate sinusoidal cell structure and function under normal conditions and their behavior in diseased settings, an understanding of their developmental aspects is needed.