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Dive into the research topics where Masato Yoneda is active.

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Featured researches published by Masato Yoneda.


Journal of Gastroenterology | 2007

High-sensitivity C-reactive protein is an independent clinical feature of nonalcoholic steatohepatitis (NASH) and also of the severity of fibrosis in NASH

Masato Yoneda; Hironori Mawatari; Koji Fujita; Hiroshi Iida; Kyoko Yonemitsu; Shingo Kato; Hirokazu Takahashi; Hiroyuki Kirikoshi; Masahiko Inamori; Yuichi Nozaki; Yasunobu Abe; Kensuke Kubota; Satoru Saito; Tomoyuki Iwasaki; Yasuo Terauchi; Shinji Togo; Shiro Maeyama; Atsushi Nakajima

BackgroundThe changes in nonalcoholic fatty liver disease (NAFLD) range over a wide spectrum, extending from steatosis to steatohepatitis (NASH). However, it has remained difficult to differentiate between NASH and nonprogressive NAFLD by clinical examination. We investigated the interrelationships between serum high-sensitivity C-reactive protein (hs-CRP) and the pathogenesis and progression of NASH.MethodsHs-CRP was measured in 100 patients with histologically verified NAFLD (29 with steatosis and 71 with NASH), and a real-time reverse transcriptase-polymerase chain reaction (RT-PCR) analysis was performed to measure the intrahepatic mRNA expressions of CRP and interleukin (IL)-6.ResultsThe results of a multiple regression analysis revealed that in comparison with cases of steatosis, hs-CRP was significantly elevated (P = 0.0048) in cases of NASH. Furthermore, among patients with NASH, hs-CRP was significantly elevated in those with advanced fibrosis compared with that in those with mild fibrosis (P = 0.0384), even after adjustment for age, sex, presence of diabetes, body mass index, visceral fat area, subcutaneous fat area, homeostasis model assessment for insulin resistance, high-density lipoprotein cholesterol, triglyceride, and low-density lipoprotein cholesterol. The results of the RT-PCR analysis showed that intrahepatic mRNA expression of CRP, but not IL-6, was increased in patients with NASH compared with those with steatosis (P = 0.0228).ConclusionsThis is the first report to demonstrate consistent and profound elevation of hs-CRP in cases of NASH compared with in cases of simple nonprogressive steatosis. Our results suggest that hs-CRP may be a clinical feature that not only distinguishes NASH from simple nonprogressive steatosis but also indicates the severity of hepatic fibrosis in cases of NASH.


Journal of Hepatology | 2009

Long-term combination therapy of ezetimibe and acarbose for non-alcoholic fatty liver disease

Yuichi Nozaki; Koji Fujita; Masato Yoneda; Koichiro Wada; Yoshiyasu Shinohara; Hirokazu Takahashi; Hiroyuki Kirikoshi; Masahiko Inamori; Kensuke Kubota; Satoru Saito; Tetsuya Mizoue; Naohiko Masaki; Yoji Nagashima; Yasuo Terauchi; Atsushi Nakajima

BACKGROUND/AIMS Non-alcoholic fatty liver disease (NAFLD) is a hepatic manifestation of metabolic syndrome that is closely associated with multiple factors such as obesity, hyperlipidemia, type 2 diabetes mellitus and hypertension, making it difficult to treat NAFLD effectively using any monotherapy available to date. In this study, we propose a novel combination therapy for NAFLD comprising ezetimibe (EZ), a cholesterol absorption inhibitor, and acarbose (AC), an alpha-glucosidase inhibitor. METHODS C57BL/6J mice were divided into five treatment groups as follows: basal diet (BD), high-fat diet (HFD) only, HFD with EZ (5mg/kg/day), HFD with AC (100mg/kg/day), and HFD with both EZ and AC for 24 weeks. RESULTS Long-term combination therapy with EZ and AC significantly reduced steatosis, inflammation and fibrosis in the liver, compared with long-term monotherapy with either drug, in an HFD-induced NAFLD mouse model; the combination therapy also significantly increased the expression of microsomal triglyceride transfer protein (MTP) and peroxisome proliferators-activated receptor-alpha1 (PPAR-alpha1) in the liver, compared with either monotherapy, which may have led to the improvement in lipid metabolic disorder seen in this model. CONCLUSIONS Combination therapy with EZ and AC for 24 weeks improved the histopathological findings in a mouse model of NAFLD.


Liver International | 2009

Association between angiotensin II type 1 receptor polymorphisms and the occurrence of nonalcoholic fatty liver disease.

Masato Yoneda; Kikuko Hotta; Yuichi Nozaki; Hiroki Endo; Takashi Uchiyama; Hironori Mawatari; Hiroshi Iida; Shingo Kato; Koji Fujita; Hirokazu Takahashi; Hiroyuki Kirikoshi; Noritoshi Kobayashi; Masahiko Inamori; Yasunobu Abe; Kensuke Kubota; Satoru Saito; Shiro Maeyama; Koichiro Wada; Atsushi Nakajima

Background: Nonalcoholic fatty liver disease (NAFLD) is one of the most common causes of chronic liver injury in many countries. Genetic factors are important for the development of NAFLD, as well as environmental factors. Recently an angiotensin II type 1 receptor (AGTR1) has been recognized as important in the aetiology of fibrosis in the liver.


Digestion | 2009

Incidence of Small Bowel Injury Induced by Low-Dose Aspirin: A Crossover Study Using Capsule Endoscopy in Healthy Volunteers

Hiroki Endo; Kunihiro Hosono; Masahiko Inamori; Shingo Kato; Yuichi Nozaki; Kyoko Yoneda; Tomoyuki Akiyama; Koji Fujita; Hirokazu Takahashi; Masato Yoneda; Yasunobu Abe; Hiroyuki Kirikoshi; Noritoshi Kobayashi; Kensuke Kubota; Satoru Saito; Nobuyuki Matsuhashi; Atsushi Nakajima

Background and Aims: Small intestinal toxicity of low-dose aspirin remains unclear. The purpose of this capsule endoscopy study was to assess the incidence of small bowel injury in healthy volunteers treated with short-term low-dose aspirin. Methods: Healthy subjects were randomly assigned to receive low-dose aspirin for 14 days (Aspirin group) or no drugs for 14 days (Control group). The two treatment occasions were separated by a washout period of at least 4 weeks. All subjects underwent capsule endoscopy at the end of each treatment period. Results: After 2 weeks of treatment, the percentages of subjects with small bowel pathology were 80% in the Aspirin group compared with 20% in the Control group (p = 0.023). The incidence of small bowel mucosal breaks in the Aspirin group was higher than that in the Control group, although the difference was not significant (30 vs. 0%; p = 0.210). Conclusions: This is the first pilot study using capsule endoscopy to report on the relation between small bowel injury and low-dose aspirin. Among the healthy subjects, the short-term administration of low-dose aspirin was associated with a mild mucosal inflammation of the small bowel.


Gut | 2008

Effectiveness of antiplatelet drugs against experimental non-alcoholic fatty liver disease

Koji Fujita; Yuichi Nozaki; Koichiro Wada; Masato Yoneda; Hiroki Endo; Hirokazu Takahashi; Tomoyuki Iwasaki; Masahiko Inamori; Yasunobu Abe; Noritoshi Kobayashi; Hiroyuki Kirikoshi; Kensuke Kubota; Satoru Saito; Yoji Nagashima; Atsushi Nakajima

Objective: No effective drugs have been developed to date to prevent or treat non-alcoholic fatty liver disease (NAFLD), although diet modification and exercise to improve obesity have been attempted. Therefore, development of a novel drug/strategy to treat NAFLD is urgently needed. In the present study, a novel concept is proposed for the treatment of NAFLD. Methods: Fisher 344 male rats were given a choline-deficient, l-amino acid-defined (CDAA) diet or a high-fat high-calorie (HF/HC) diet with or without the antiplatelet agents, aspirin, ticlopidine or cilostazol for 16 weeks. Liver steatosis, inflammation and fibrosis, and the possible mechanisms involved were investigated. Results: All three antiplatelet drugs, namely aspirin, ticlopidine and cilostazol, significantly attenuated liver steatosis, inflammation and fibrosis in the CDAA diet group. Of the three agents, cilostazol was the most effective, and the drug also suppressed HF/HC diet-induced liver steatosis. Cilostazol appeared to exert its beneficial effect against NAFLD by suppressing mitogen-activated protein kinase activation induced by oxidative stress and platelet-derived growth factor via intercepting signal transduction from Akt to c-Raf. Conclusion: Antiplatelet agents, especially cilostazol, offer the promise of becoming key agents for the treatment of NAFLD.


Digestive Diseases and Sciences | 2007

Telmisartan, An Angiotensin II Type 1 Receptor Blocker, Controls Progress of Nonalcoholic Steatohepatitis in Rats

Koji Fujita; Masato Yoneda; Koichiro Wada; Hironori Mawatari; Hirokazu Takahashi; Hiroyuki Kirikoshi; Masahiko Inamori; Yuichi Nozaki; Shiro Maeyama; Satoru Saito; Tomoyuki Iwasaki; Yasuo Terauchi; Atsushi Nakajima

The term nonalcoholic steatohepatitis (NASH) has recently been proposed to identify a fatty liver disease accompanied by diffuse fatty infiltration and inflammation. However, no drug therapy has been established for NASH as yet. In the present study, we demonstrate the effect of the angiotensin II type 1 receptor antagonist telmisartan on the development of NASH in a rat model. Telmisartan, but not the angiotensin receptor antagonist valsartan, markedly attenuated hepatic steatosis, inflammation, and fibrosis in these rats. The quantitative parameters of steatosis, inflammation, and fibrosis were also ameliorated by treatment with telmisartan. Compared with telmisartan, the peroxisome proliferator-activated receptor-γ agonist pioglitazone attenuated hepatic steatosis and fibrosis of the liver to a similar degree. However, telmisartan, but not pioglitazone, dramatically decreased both subcutaneous and visceral fat. In conclusion, these results indicated that telmisartan should be the drug of first choice for the treatment of patients with NASH.


BMC Gastroenterology | 2008

Association between PPARGC1A polymorphisms and the occurrence of nonalcoholic fatty liver disease (NAFLD)

Masato Yoneda; Kikuko Hotta; Yuichi Nozaki; Hiroki Endo; Takashi Uchiyama; Hironori Mawatari; Hiroshi Iida; Shingo Kato; Kunihiro Hosono; Koji Fujita; Kyoko Yoneda; Hirokazu Takahashi; Hiroyuki Kirikoshi; Noritoshi Kobayashi; Masahiko Inamori; Yasunobu Abe; Kensuke Kubota; Satoru Saito; Shiro Maeyama; Koichiro Wada; Atsushi Nakajima

BackgroundGenetic factors as well as environmental factors are important in the development of NAFLD and in this study we investigated associations between polymorphisms of peroxisome proliferators-activated receptor γ coactivator 1α polymorphism (PPARGC1A) and NAFLD.AimsWe recruited 115 patients with biopsy-proven NAFLD, 65 with NASH and 50 with simple steatosis, and 441 healthy control subjects and investigated 15 SNPs of PPARGC1A.ResultsSNP rs2290602 had the lowest p value in the dominant mode (p = 0.00095), and the odds ratio for NAFLD (95% CI) was 2.73 (1.48 – 5.06). rs2290602 was significantly associated with NAFLD even when the most conservative Bonferronis correction was applied (p = 0.0143). The frequency of the T allele of rs2290602 was significantly higher in the NASH patients than in the control subjects (p = 0.00093, allele frequency mode), and its frequency in the NASH patients tended to be higher than in the simple steatosis patients (p = 0.09). The results of the real-time RT-PCR study showed that intrahepatic mRNA expression of PPARGC1A was lower in the TT group than in the GG or GT group at SNP rs2290602 (p = 0.0454).ConclusionThis is the first study to demonstrate a significant association between genetic variations in PPARGC1A and NAFLD. This finding suggested that PPARGC1A polymorphism and lower expression of PPARGC1A mRNA in the liver are an important genetic contribution to etiology of NAFLD.


BMC Gastroenterology | 2008

Plasma Pentraxin3 is a Novel Marker for Nonalcoholic Steatohepatitis (NASH)

Masato Yoneda; Takashi Uchiyama; Shingo Kato; Hiroki Endo; Koji Fujita; Kyoko Yoneda; Hironori Mawatari; Hiroshi Iida; Hirokazu Takahashi; Hiroyuki Kirikoshi; Masahiko Inamori; Yuichi Nozaki; Noritoshi Kobayashi; Kensuke Kubota; Satoru Saito; Shiro Maeyama; Mina Sagara; Hiroyuki Aburatani; Tatsuhiko Kodama; Atsushi Nakajima

BackgroundThe changes in the liver in nonalcoholic fatty liver disease (NAFLD) range over a wide spectrum, extending from steatosis to steatohepatitis (NASH). However it has remained difficult to differentiate between NASH and non-progressive NAFLD on the basis of the clinical findings alone.AimsIn this study we investigated the clinical usefulness of plasma Pentraxin3 (PTX3) levels to predict NASH. Plasma PTX3 was measured in 70 patients with histologically verified NAFLD (28 with non-NASH and 42 with NASH) and 10 healthy control subjects.ResultsThe plasma PTX3 level was significantly higher in the NASH cases than in the non-NASH cases (p = 0.0021) and control subjects (p = 0.045). And the plasma PTX3 level was significantly higher in the stages 3–4 NAFLD cases than in the stages 0–2 NAFLD cases (p < 0.0001). The PTX3 values were closely correlated with the stages of liver fibrosis (p < 0.0001, Kruskal-Wallis test). To detect NASH compared with non-NASH, the area under the curve for plasma PTX3 were 0.755, and to detect stages 3–4 NAFLD compared with stages 0–2 NAFLD, the area under the curve for plasma PTX3 were 0.850.ConclusionThis is the first study to demonstrate consistent and profound elevation of plasma PTX3 levels in NASH in comparison with non-NASH. The results suggest that plasma PTX3 levels may not only be laboratory values that differentiate NASH from non-NASH, but marker of the severity of hepatic fibrosis in NASH.


Alcoholism: Clinical and Experimental Research | 2010

Nitric oxide plays a crucial role in the development/progression of nonalcoholic steatohepatitis in the choline-deficient, l-amino acid-defined diet-fed rat model.

Koji Fujita; Yuichi Nozaki; Masato Yoneda; Koichiro Wada; Hirokazu Takahashi; Hiroyuki Kirikoshi; Masahiko Inamori; Satoru Saito; Tomoyuki Iwasaki; Yasuo Terauchi; Shiro Maeyama; Atsushi Nakajima

BACKGROUND The pathogenesis of nonalcoholic steatohepatitis (NASH) is still unclear. Recently, the 2-hit hypothesis was proposed, in which nitric oxide production, representing oxidative stress, was proposed as a very important candidate for the second hit. METHODS The total study period was 10 weeks. A total of 20 rats were randomly divided into 2 groups. Group 1 was administered the Choline-Deficient, l-Amino Acid-Defined diet to produce a NASH model, and Group 2 as control received the Choline-Sufficient, l-Amino Acid-defined diet. The blood and tissue concentrations of nitrate + nitrite were measured using the Griess reagent and the expression levels of inducible nitric oxide synthase (iNOS) proteins and mRNA was determined by Western blotting. RESULTS In regard to nitric oxide (NO) and NO metabolites, there were significant differences in the blood (especially portal venous blood) as well as tissue (liver and visceral fat) concentrations between the 2 animal groups; the amounts of NO metabolites in the tissues were much higher in the NASH models. The level of nitrotyrosine was much markedly higher in the NASH models than in the controls. In regard to the tissue expression of iNOS a significant difference between the 2 groups was found in the visceral fat, especially in the mesenterium. CONCLUSIONS Based on these results, we hypothesize that the iNOS expression and NO levels in the visceral fat increase, with increased diffusion of NO and its metabolites into the liver, resulting in increased nitrotyrosine formation in the liver; this, in turn, induces inflammation, apoptosis, and fibrosis in the liver, which are one of the characteristic features of NASH.


Gastrointestinal Endoscopy | 2008

Differentiating sclerosing cholangitis caused by autoimmune pancreatitis and primary sclerosing cholangitis according to endoscopic duodenal papillary features

Kensuke Kubota; Shingo Kato; Tomoyuki Akiyama; Masato Yoneda; Koji Fujita; Masami Ogawa; Masahiko Inamori; Noritoshi Kobayashi; Satoru Saito; Yukio Kakuta; Hisashi Ohshiro; Atsushi Nakajima

BACKGROUND Differentiating primary sclerosing cholangitis (PSC) and sclerosing cholangitis caused by autoimmune pancreatitis (SC-AIP) is often challenging. Recently, endoscopic findings of the duodenal papilla in cases with AIP or PSC were reported by Unno and Parlak, although the endoscopic differentiation of these 2 conditions has not yet been fully clarified. OBJECTIVE Our purpose was to clarify the endoscopic findings of the duodenal papilla in patients with SC-AIP and those with PSC and to determine criteria for the differentiation of these conditions. DESIGN Case series. SETTING Retrospective. PATIENTS Twenty-seven patients with SC-AIP and 12 patients with PSC who had undergone ERCP were identified from our database. We reviewed these records to determine whether the duodenal papillary findings (swollen papilla/normal papilla/small papilla) might be potentially useful for differentiating SC-AIP and PSC. Immunohistopathological findings for the duodenal papilla were also examined by using immunoglobulin G4 (IgG4) among the infiltrating plasma cells. INTERVENTIONS ERCP, biopsy specimen taken from duodenal papilla. MAIN OUTCOME MEASUREMENTS The presence of a swollen duodenal papilla with IgG4-positive plasma cells was useful for discriminating SC-AIP from with PSC. RESULTS A swollen duodenal papilla was observed in 63% (17/27) of the patients with SC-AIP, whereas there was no swelling of the duodenal papilla of the patients with PSC. A small papilla was recognized in 50% (6/12) of the patients with PSC. IgG4-positive plasma cells in the duodenal papilla were significantly detected in the patients with SC-AIP but not in the patients with PSC. LIMITATION Single-center study. CONCLUSIONS Characteristic duodenal endoscopic papillary features in patients with SC-AIP, such as a swollen duodenal papilla and positive immunostaining for IgG4, might be helpful for discriminating this condition from PSC.

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Koji Fujita

Yokohama City University

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Satoru Saito

Yokohama City University

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Hiroki Endo

Yokohama City University

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Kensuke Kubota

Yokohama City University

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Yuichi Nozaki

Yokohama City University

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