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Dive into the research topics where Hiroaki Takaya is active.

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Featured researches published by Hiroaki Takaya.


Mediators of Inflammation | 2013

The Effect of Inflammatory Cytokines in Alcoholic Liver Disease

Hideto Kawaratani; Tatsuhiro Tsujimoto; Akitoshi Douhara; Hiroaki Takaya; Kei Moriya; Tadashi Namisaki; Ryuichi Noguchi; Hitoshi Yoshiji; Masao Fujimoto; Hiroshi Fukui

Alcohol is the most common cause of liver disease in the world. Chronic alcohol consumption leads to hepatocellular injury and liver inflammation. Inflammatory cytokines, such as TNF-α and IFN-γ, induce liver injury in the rat model of alcoholic liver disease (ALD). Hepatoprotective cytokines, such as IL-6, and anti-inflammatory cytokines, such as IL-10, are also associated with ALD. IL-6 improves ALD via activation of the signal transducer and activator of transcription 3 (STAT3) and the subsequent induction of a variety of hepatoprotective genes in hepatocytes. IL-10 inhibits alcoholic liver inflammation via activation of STAT3 in Kupffer cells and the subsequent inhibition of liver inflammation. Alcohol consumption promotes liver inflammation by increasing translocation of gut-derived endotoxins to the portal circulation and activating Kupffer cells through the LPS/Toll-like receptor (TLR) 4 pathways. Oxidative stress and microflora products are also associated with ALD. Interactions between pro- and anti-inflammatory cytokines and other cytokines and chemokines are likely to play important roles in the development of ALD. The present study aims to conduct a systemic review of ALD from the aspect of inflammation.


Hepatology Research | 2012

ADAMTS13 activity may predict the cumulative survival of patients with liver cirrhosis in comparison with the Child-Turcotte-Pugh score and the Model for End-Stage Liver Disease score.

Hiroaki Takaya; Masahito Uemura; Yoshihiro Fujimura; Masanori Matsumoto; Tomomi Matsuyama; Seiji Kato; Chie Morioka; Hiromichi Ishizashi; Yuji Hori; Masao Fujimoto; Tatsuhiro Tsujimoto; Hideto Kawaratani; Masahisa Toyohara; Norio Kurumatani; Hiroshi Fukui

Aim:  Decreased plasma ADAMTS13 activity (ADAMTS13:AC) results in accumulation of unusually large von Willebrand factor multimers and platelet thrombi formation. Our aim was to evaluate whether ADAMTS13:AC is a prognostic marker in patients with liver cirrhosis.


Hepatology Research | 2017

Predictive parameter of tolvaptan effectiveness in cirrhotic ascites

Hideto Kawaratani; Hiroshi Fukui; Kei Moriya; Ryuichi Noguchi; Tadashi Namisaki; Masakazu Uejima; Mitsuteru Kitade; Kosuke Takeda; Yasushi Okura; Kosuke Kaji; Norihisa Nishimura; Hiroaki Takaya; Yousuke Aihara; Yasuhiko Sawada; Shinya Sato; Kenichiro Seki; Akira Mitoro; Junichi Yamao; Hitoshi Yoshiji

The efficacy of the vasopressin V2 receptor antagonist tolvaptan for difficult‐to‐treat cirrhotic ascites has recently been reported. However, its effect is variable among patients. This study aimed to clarify the predictive factors for obtaining a good response to tolvaptan in patients with difficult‐to‐treat ascites.


Hepatology Research | 2017

Combination treatment of dipeptidyl peptidase IV inhibitor (sitagliptin) and angiotensin-II type 1 receptor blocker (losartan) suppresses progression in a nondiabetic rat model of steatohepatitis

Yasushi Okura; Tadashi Namisaki; Kei Moriya; Mitsuteru Kitade; Kosuke Takeda; Kosuke Kaji; Ryuichi Noguchi; Norihisa Nishimura; Kenichiro Seki; Hideto Kawaratani; Hiroaki Takaya; Shinya Sato; Yasuhiko Sawada; Naotaka Shimozato; Masanori Furukawa; Keisuke Nakanishi; Saikawa Soichiro; Takuya Kubo; Kiyoshi Asada; Hitoshi Yoshiji

Dipeptidyl peptidase‐4 (DPP4) inhibitors (DPP4‐I) are oral glucose‐lowering drugs for type 2 diabetes mellitus. Previously, we reported that DPP4‐I (sitagliptin) exerted suppressive effects on experimental liver fibrosis in rats. Blockade of the renin–angiotensin system by angiotensin‐II type 1 receptor blocker (losartan), commonly used in the management of hypertension, has been shown to significantly alleviate hepatic fibrogenesis and carcinogenesis. We aimed to elucidate the effects and possible mechanisms of a sitagliptin + losartan combination on the progression of non‐diabetic non‐alcoholic steatohepatitis (NASH) in a rat model.


World Journal of Gastroenterology | 2017

Rifaximin ameliorates hepatic encephalopathy and endotoxemia without affecting the gut microbiome diversity

Kosuke Kaji; Hiroaki Takaya; Soichiro Saikawa; Masanori Furukawa; Shinya Sato; Hideto Kawaratani; Mitsuteru Kitade; Kei Moriya; Tadashi Namisaki; Takemi Akahane; Akira Mitoro; Hitoshi Yoshiji

AIM To determine the efficacy of rifaximin for hepatic encephalopathy (HE) with the linkage of gut microbiome in decompensated cirrhotic patients. METHODS Twenty patients (12 men and 8 women; median age, 66.8 years; range, 46-81 years) with decompensated cirrhosis (Child-pugh score > 7) underwent cognitive neuropsychological testing, endotoxin analysis, and fecal microbiome assessment at baseline and after 4 wk of treatment with rifaximin 400 mg thrice a day. HE was determined by serum ammonia level and number connection test (NCT)-A. Changes in whole blood endotoxin activity (EA) was analyzed by endotoxin activity assay. Fecal microbiome was assessed by 16S ribosome RNA (rRNA) gene sequencing. RESULTS Treatment with rifaximin for 4 wk improved hyperammonemia (from 90.6 ± 23.9 μg/dL to 73.1 ± 33.1 μg/dL; P < 0.05) and time required for NCT (from 68.2 ± 17.4 s to 54.9 ± 20.3 s; P < 0.05) in patients who had higher levels at baseline. Endotoxin activity was reduced (from 0.43 ± 0.03 to 0.32 ± 0.09; P < 0.05) in direct correlation with decrease in serum ammonia levels (r = 0.5886, P < 0.05). No statistically significant differences were observed in the diversity estimator (Shannon diversity index) and major components of the gut microbiome between the baseline and after treatment groups (3.948 ± 0.548 at baseline vs 3.980 ± 0.968 after treatment; P = 0.544), but the relative abundances of genus Veillonella and Streptococcus were lowered. CONCLUSION Rifaximin significantly improved cognition and reduced endotoxin activity without significantly affecting the composition of the gut microbiome in patients with decompensated cirrhosis.


European Journal of Gastroenterology & Hepatology | 2017

Clinical significance of the Scheuer histological staging system for primary biliary cholangitis in Japanese patients.

Tadashi Namisaki; Kei Moriya; Mitsuteru Kitade; Hideto Kawaratani; Kosuke Takeda; Yasushi Okura; Hiroaki Takaya; Norihisa Nishimura; Kenichiro Seki; Kosuke Kaji; Shinya Sato; Yasuhiko Sawada; Junichi Yamao; Akira Mitoro; Masakazu Uejima; Tsuyoshi Mashitani; Naotaka Shimozato; Keisuke Nakanishi; Masanori Furukawa; Soichiro Saikawa; Takuya Kubo; Hitoshi Yoshiji

Background Inadequate response to ursodeoxycholic acid (UDCA) is associated with unfavorable outcomes in patients with primary biliary cholangitis (PBC). We aimed to identify surrogate markers for predicting long-term prognosis and biochemical response to UDCA in patients with PBC. Patients and methods In this single-center, retrospective study, 99 patients with PBC were classified into responders (n=53) and nonresponders (n=46) based on reductions in the &ggr;-glutamyl transpeptidase levels at 1 year after initiating UDCA therapy (Nara criteria). We assessed whether the criteria for patentability by different countries are useful in predicting the prognosis of PBC. The accuracy of Scheuer and Nakanuma staging systems in predicting prognosis and treatment response was compared. Results Nara definition had comparable utility to the Paris-II definition for selecting patients in whom UDCA monotherapy can be safely continued. Patients at Scheuer stage 1 had a significantly better prognosis than those at Scheuer stages 3 or 4 (P<0.05 and 0.0001, respectively). Patients at Nakanuma stage 4 had decreased survival compared with those at stage 1 (P<0.05). The proportion of responders to nonresponders was significantly higher in stages 1–3 PBC than in stage 4 PBC, according to both staging systems (P<0.05 for both). All patients with Scheuer stage 4 PBC were nonresponders, whereas only 28.6% (2/7) of those with Nakanuma stage 4 PBC were responders. Conclusion The Scheuer staging system had greater utility in predicting long-term prognosis and UDCA response than the Nakanuma staging system.


Hepatic Medicine : Evidence and Research | 2018

Management of refractory cirrhotic ascites: challenges and solutions

Hiroshi Fukui; Hideto Kawaratani; Kosuke Kaji; Hiroaki Takaya; Hitoshi Yoshiji

Among the various risky complications of liver cirrhosis, refractory ascites is associated with poor survival of cirrhotics and persistently worsens their quality of life (QOL). Major clinical guidelines worldwide define refractory ascites as ascites that cannot be managed by medical therapy either because of a lack of response to maximum doses of diuretics or because patients develop complications related to diuretic therapy that preclude the use of an effective dose of diuretics. Due to the difficulty in receiving a liver transplantation (LT), the ultimate solution for refractory ascites, most cirrhotic patients have selected the palliative therapy such as repeated serial paracentesis, transjugular intrahepatic portosystemic shunt, or peritoneovenous shunt to improve their QOL. During the past several decades, new interventions and methodologies, such as indwelling peritoneal catheter, peritoneal-urinary drainage, and cell-free and concentrated ascites reinfusion therapy, have been introduced. In addition, new medical treatments with vasoconstrictors or vasopressin V2 receptor antagonists have been proposed. Both the benefits and risks of these old and new modalities have been extensively studied in relation to the pathophysiological changes in ascites formation. Although the best solution for refractory ascites is to eliminate hepatic failure either by LT or by causal treatment, the selection of the best palliative therapy for individual patients is of utmost importance, aiming at achieving the longest possible, comfortable life. This review briefly summarizes the changing landscape of variable treatment modalities for cirrhotic patients with refractory ascites, aiming at clarifying their possibilities and limitations. Evolving issues with regard to the impact of gut-derived systemic and local infection on the clinical course of cirrhotic patients have paved the way for the development of a new gut microbiome-based therapeutics. Thus, it should be further investigated whether the early therapeutic approach to gut dysbiosis provides a better solution for the management of cirrhotic ascites.


BMC Gastroenterology | 2018

Treatment of long-segment Barrett’s adenocarcinoma by complete circular endoscopic submucosal dissection: a case report

Miki Kaneko; Akira Mitoro; Motoyuki Yoshida; Masayoshi Sawai; Yasushi Okura; Masanori Furukawa; Tadashi Namisaki; Kei Moriya; Takemi Akahane; Hideto Kawaratani; Mitsuteru Kitade; Kousuke Kaji; Hiroaki Takaya; Yasuhiko Sawada; Kenichiro Seki; Shinya Sato; Tomomi Fujii; Junichi Yamao; Chiho Obayashi; Hitoshi Yoshiji

BackgroundWe present the first description of en bloc endoscopic submucosal dissection (ESD) for total circumferential Barrett’s adenocarcinoma, predominantly of the long-segment Barrett’s esophagus (LSBE), with a 2-year follow-up and management strategies for esophageal stricture prevention.Case presentationA 59-year-old man was diagnosed with LSBE and Barrett’s adenocarcinoma by esophagogastroduodenoscopy (EGD). A 55-mm-long circumferential tumor was completely resected by ESD. Histopathology revealed a well-differentiated adenocarcinoma within the LSBE superficial muscularis mucosa. For post-ESD stricture prevention, the patient underwent an endoscopic triamcinolone injection administration, oral prednisolone administration, and preemptive endoscopic balloon dilatation. Two years later, there is no evidence of esophageal stricture or recurrence.ConclusionsESD appears to be a safe, effective option for total circumferential Barrett’s adenocarcinoma in LSBE.


Oncology Letters | 2017

Predisposing factors for hepatocellular carcinoma recurrence following initial remission after transcatheter arterial chemoembolization

Akitoshi Douhara; Tadashi Namisaki; Kei Moriya; Mitsuteru Kitade; Kosuke Kaji; Hideto Kawaratani; Kosuke Takeda; Yasushi Okura; Hiroaki Takaya; Ryuichi Noguchi; Norihisa Nishimura; Kenichiro Seki; Shinya Sato; Yasuhiko Sawada; Junichi Yamao; Akira Mitoro; Masakazu Uejima; Tsuyoshi Mashitani; Naotaka Shimozato; Soichiro Saikawa; Keisuke Nakanishi; Masanori Furukawa; Takuya Kubo; Hitoshi Yoshiji

Hepatocellular carcinoma (HCC) is prone to recurrence following curative treatment. The purpose of the present study was to identify the predisposing factors of HCC recurrence following complete remission achieved by transarterial chemoembolization (TACE). A retrospective cohort study of 70 consecutive patients with HCC who underwent TACE as the initial treatment was conducted. The patients were divided into two groups according to their 1-year disease-free survival (DFS) status; the early recurrence group (ER group; n=32), with HCC recurring within 1 year of initial TACE; and the non-early recurrence group (NER group; n=38), who did not experience recurrence within 1 year. The parameters identified as significantly associated with DFS time on univariate analysis were aspartate aminotransferase (AST), alanine aminotransferase and α-fetoprotein levels, as well as the tumor number (P=0.003, P=0.027, P=0.002 and P=0.005, respectively). Multivariate analysis revealed that AST levels and tumor number were significantly associated with a shorter DFS period (P=0.009 and P=0.038, respectively). The Mantel-Haenszel test revealed a significant trend of decreasing DFS with increasing tumor number. Among the patients with HCC in the ER group, locoregional recurrence occurred more frequently in those who received TACE alone compared with those treated with TACE combined with radiofrequency ablation treatment. In summary, multinodularity of HCC is the most potent predictive factor for the recurrence of HCC within 1 year of initial TACE.


Hepatology Research | 2017

Liver fibrosis progression predicts survival in patients with primary biliary cirrhosis.

Tadashi Namisaki; Kei Moriya; Ryuichi Noguchi; Mitsuteru Kitade; Hideto Kawaratani; Junichi Yamao; Akira Mitoro; Motoyuki Yoshida; Masayoshi Sawai; Masakazu Uejima; Tsuyoshi Mashitani; Kosuke Takeda; Yasushi Okura; Kosuke Kaji; Hiroaki Takaya; Yosuke Aihara; Akitoshi Douhara; Norihisa Nishimura; Yasuhiko Sawada; Shinya Sato; Kenichiro Seki; Hitoshi Yoshiji

The prognosis and natural history of primary biliary cirrhosis (PBC) has improved, and the clinical end‐point for PBC needs to be discovered. We aimed to identify surrogate markers for predicting long‐term prognosis in patients with PBC.

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Hitoshi Yoshiji

National Archives and Records Administration

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Kei Moriya

Nara Medical University

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Shinya Sato

Nara Medical University

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Kosuke Kaji

Nara Medical University

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Akira Mitoro

Nara Medical University

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