Tomoyuki Shiozawa
Juntendo University
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Featured researches published by Tomoyuki Shiozawa.
Circulation | 2015
Takuma Yoshihara; Kazunori Shimada; Kosuke Fukao; Eiryu Sai; Yayoi Sato-Okabayashi; Rie Matsumori; Tomoyuki Shiozawa; Hamad Alshahi; Tetsuro Miyazaki; Hiroyuki Daida
BACKGROUND Dietary intake of ω3 polyunsaturated fatty acids (ω3-PUFAs) reduces progression of atherosclerosis and prevents future cardiovascular events. Macrophages are key players in the pathogenesis of aortic aneurysm. The effects of ω3-PUFAs on abdominal aortic aneurysm (AAA) formation and macrophage-mediated inflammation remain unclear. METHODS AND RESULTS: The AAA model was developed by angiotensin II infusion in apolipoprotein E-deficient mice. Mice were supplemented with eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA). The development of AAA lesions and macrophage infiltration in the aorta were analyzed. Gene expression of inflammatory markers in aortic tissues and peritoneal macrophages were measured by using quantitative polymerase chain reaction. AAA formation and macrophage infiltration were significantly suppressed after EPA and DHA administration. EPA administration and DHA administration significantly decreased the expression of tumor necrosis factor-α, monocyte chemoattractant protein-1, transforming growth factor-β, matrix metalloproteinases (MMP)-2, MMP-9, and vascular cell adhesion molecule-1 in the aortas. The expression of arginase 2, which is a marker of pro-inflammatory macrophages, was significantly lower and that of Ym1, which is a marker of anti-inflammatory macrophages, and was significantly higher after EPA and DHA administration. The same trends were observed in peritoneal macrophages after EPA and DHA administration. CONCLUSIONS Dietary intake of EPA and DHA prevented AAA development through the inhibition of aortic and macrophage-mediated inflammation.
International Journal of Vascular Medicine | 2015
Hamad Al Shahi; Kazunori Shimada; Katsumi Miyauchi; Takuma Yoshihara; Eiryu Sai; Tomoyuki Shiozawa; Ryo Naito; Tatsuro Aikawa; Shohei Ouchi; Tomoyasu Kadoguchi; Tetsuro Miyazaki; Hiroyuki Daida
Objective. We evaluated inflammatory cytokines and chemokine in peripheral blood mononuclear cells (PBMCs) in patients with either acute coronary syndrome (ACS) or stable coronary artery disease (CAD). Methods. We enrolled 20 ACS patients and 50 stable CAD patients without previous history of ACS who underwent cardiac catheterization. Patients with an estimated glomerular filtration rate of ≤30 mL/min/1.73 m2 and C-reactive protein of ≥1.0 mg/dL were excluded. Blood samples were collected from the patients just before catheterization, and PBMCs were isolated from the whole blood. The levels of inflammatory cytokines and chemokine were measured by using real-time quantitative polymerase chain reaction and immunoassays. Results. The expression of tumor necrosis factor alpha (TNF-α), interleukin- (IL-) 6, IL-10, IL-23A, IL-27, and IL-37 was significantly higher in the ACS group than in the CAD group (P < 0.05). In contrast, the expression of IL-33 was significantly lower in the ACS group than in the CAD group (P < 0.05). The ACS patients had higher plasma levels of TNF-α, IL-6, and IL-10 in the ACS group than in the CAD group. Conclusion. Circulating levels of pro-/anti-inflammatory cytokines, including IL-23A, IL-27, IL-33, and IL-37, may be associated with the pathogenesis of atherosclerosis in ACS patients.
Journal of Atherosclerosis and Thrombosis | 2017
Tatsuro Aikawa; Tetsuro Miyazaki; Kazunori Shimada; Yurina Sugita; Megumi Shimizu; Shohei Ouchi; Tomoyasu Kadoguchi; Yasutaka Yokoyama; Tomoyuki Shiozawa; Masaru Hiki; Shuhei Takahashi; Hamad Al Shahi; Shizuyuki Dohi; Atsushi Amano; Hiroyuki Daida
Aim: Omega-3 polyunsaturated fatty acids (PUFAs) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been reported to reduce the risk of cardiovascular disease. However, whether omega-3 PUFAs are involved in the pathogenesis of abdominal aortic aneurysms (AAA) remains unclear. Methods: We analyzed 67 consecutive patients admitted for the elective surgical repair of AAA. We investigated the association of serum EPA and DHA levels as well as the EPA/AA ratio with the size of AAA assessed using three-dimensional reconstructed computed tomography images. Results: Mean patient age was 70 ± 9 years and 60 patients were male. Serum EPA and DHA levels were 75.2 ± 35.7 µg/mL and 146.1 ± 48.5 µg/mL, respectively. EPA/AA ratio was 0.44 ± 0.22, which was lower than those in healthy Japanese subject and equivalent to those in Japanese patients with coronary artery disease as previously reported. Mean of the maximum AAA diameter was 56.4 ± 8.9 mm, and serum EPA levels and EPA/AA ratio negatively correlated with it (r = −0.32 and r = −0.32, respectively). Multiple liner regression analysis showed that EPA levels were significant independent factor contributing to the maximum AAA diameter. Furthermore, low serum EPA levels and low EPA/AA ratio were significantly associated with the growth rate of AAA diameter (r = −0.43 and r = −0.33, respectively). Conclusion: EPA levels in patients with AAA were relatively low. Low serum EPA levels and EPA/AA ratio were associated with the size and growth rate of AAA.
Journal of Arrhythmia | 2017
Sayaka Komatsu; Masataka Sumiyoshi; Seiji Miura; Yuki Kimura; Tomoyuki Shiozawa; Keiko Hirano; Fuminori Odagiri; Haruna Tabuchi; Hidemori Hayashi; Gaku Sekita; Takashi Tokano; Yuji Nakazato; Hiroyuki Daida
Paroxysmal atrioventricular block (P‐AVB) is a well‐known cause of syncope; however, its underlying mechanism is difficult to determine. This study aimed to evaluate a new ECG index, the “vagal score (VS),” to determine the mechanism of P‐AVB.
Frontiers in Physiology | 2018
Tomoyasu Kadoguchi; Kazunori Shimada; Hiroshi Koide; Tetsuro Miyazaki; Tomoyuki Shiozawa; Shuhei Takahashi; Tatsuro Aikawa; Shohei Ouchi; Kenichi Kitamura; Yurina Sugita; Al Shahi Hamad; Mitsuhiro Kunimoto; Yayoi Sato-Okabayashi; Koji Akita; Kikuo Isoda; Hiroyuki Daida
Background: Muscle wasting is a debilitating phenotype associated with chronic heart failure (CHF). We have previously demonstrated that angiotensin II (AII) directly induces muscle wasting in mice through the activation of NADPH oxidase (Nox). In this study, we tested the hypothesis that deficiency of NADPH oxidase 4 (Nox4), a major source of oxidative stress, ameliorates AII-induced muscle wasting through the regulation of redox balance. Methods and Results: Nox4 knockout (KO) and wild-type (WT) mice were used. At baseline, there were no differences in physical characteristics between the WT and KO mice. Saline (vehicle, V) or AII was infused via osmotic minipumps for 4 weeks, after which, the WT + AII mice showed significant increases in Nox activity and NOX4 protein compared with the WT + V mice, as well as decreases in body weight, gastrocnemius muscle weight, and myocyte cross-sectional area. These changes were significantly attenuated in the KO + AII mice (27 ± 1 vs. 31 ± 1 g, 385 ± 3 vs. 438 ± 13 mg, and 1,330 ± 30 vs. 2281 ± 150 μm2, respectively, all P < 0.05). The expression levels of phospho-Akt decreased, whereas those of muscle RING Finger-1 (MuRF-1) and MAFbx/atrogin-1 significantly increased in the WT + AII mice compared with the WT + V mice. Furthermore, nuclear factor erythroid-derived 2-like 2 (Nrf2) and the expression levels of Nrf2-regulated genes significantly decreased in the WT + AII mice compared with the WT + V mice. These changes were significantly attenuated in the KO + AII mice (P < 0.05). Conclusion: Nox4 deficiency attenuated AII-induced muscle wasting, partially through the regulation of Nrf2. The Nox4–Nrf2 axis may play an important role in the development of AII-induced muscle wasting.
Nutrients | 2017
Shohei Ouchi; Tetsuro Miyazaki; Kazunori Shimada; Yurina Sugita; Megumi Shimizu; Azusa Murata; Takao Kato; Tatsuro Aikawa; Shoko Suda; Tomoyuki Shiozawa; Masaru Hiki; Shuhei Takahashi; Hiroshi Iwata; Takatoshi Kasai; Katsumi Miyauchi; Hiroyuki Daida
The clinical significance of polyunsaturated fatty acids (PUFAs) in acute decompensated heart failure (ADHF) in various nutritional statuses remains unclear. For this study, we enrolled 267 patients with ADHF admitted to the cardiac intensive care unit at Juntendo University hospital between April 2012 and March 2014. The association between long-term mortality, the geriatric nutritional risk index (GNRI), and levels of PUFAs, including eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), dihomo-gamma-linolenic acid (DGLA), and arachidonic acid (AA) was investigated. The median age was 73 (64–82) years, and mortality was 29% (62 patients). The event-free survival rates for all-cause death were higher in patients with high PUFA levels or GNRI than in those with low PUFA levels or GNRI (p < 0.05 for all). In particular, high DGLA in the low-GNRI group and high DHA or AA in the high-GNRI group were associated with high event-free survival (p < 0.05 for all). After accounting for confounding variables, DHA, DGLA, and AA, but not EPA, were associated with long-term mortality (p < 0.01 for all). This study concludes that in patients with ADHF, decreased levels of DHA, DGLA, and AA are independently associated with long-term mortality in the various nutritional statuses.
Journal of Atherosclerosis and Thrombosis | 2017
Masaru Hiki; Tetsuro Miyazaki; Kazunori Shimada; Yurina Sugita; Megumi Shimizu; Tatsuro Aikawa; Shohei Ouchi; Tomoyuki Shiozawa; Kiyoshi Takasu; Shuhei Takahashi; Atsutoshi Takagi; Katsumi Miyauchi; Hiroyuki Daida
Aim: Polyunsaturated fatty acids (PUFAs) take part in various biological events linked to the pathogenesis of venous thromboembolism (VTE), including inflammation, endothelial dysfunction, and hypercoagulability. Several studies have demonstrated the association between PUFAs and the occurrence of VTE. However, the role of PUFAs in the pathogenesis of VTE remains unclear. Methods: We enrolled 45 patients with acute VTE and 37 age-, gender-, and body mass indexmatched healthy volunteers to examine their PUFA levels. Serum omega 3 (eicosapentaenoic acid: EPA and docosahexaenoic acid: DHA) and omega 6 (dihomogammalinolenic acid: DGLA and arachidonic acid: AA) fatty acids levels were measured within 24 h of admission. Results: Patients with VTE showed significantly higher AA and lower EPA levels, and lower EPA/AA ratios than the controls. Multivariate analysis revealed that AA was an independent marker for VTE. In addition, we divided the patients based on their median age (58 years old). The younger patients with VTE showed significantly lower EPA/AA levels than their age-matched controls, whereas older patients with VTE showed a significantly higher AA/DGLA levels than the older controls. Conclusions: High serum AA levels and low EPA levels are associated with the development of acute VTE, suggesting that the imbalance of PUFAs may be a potential therapeutic target for preventing acute VTE.
Journal of Heart and Cardiology | 2016
Tomoyuki Shiozawa; Kazunori Shimada; Gaku Sekita; Hidemori Hayashi; Haruna Tabuchi; Sayaka Komatsu; Tetsuro Miyazaki; Katsumi Miyauchi; Jun Shitara; Takuma Yoshihara; Eiryu Sai; Masayuki Shiozaki; Kosuke Fukao; Yoshifumi Fukushima; Shinichiro Yamagami; Satoru Suwa; Youichi Katoh; Yasumasa Fujiwara; Hiroshi Ikeda; Masataka Sumiyoshi; Yuji Nakazato; Hiroyuki Daida; Ommega Internationals
Objective: Psychological triggers, such as emotional stress, increase the incidence of acute cardiovascular events. The association between soccer championships and risk of cardiovascular events remains controversial. A World Cup Soccer (WCS) match involving a national team might be a strong enough trigger to induce cardiovascular events. However, there are no reports of a multicenter study that has investigated the relationship between watching WCS and cardiac arrhythmia. Methods: We assessed 25 patients who were evaluated for ischemic changes and/or arrhythmia using 24-h Holter electrocardiography in four cardiology divisions during WCS 2014. The patients were divided into two groups: the watching (W) group consisted of 7 patients who watched WCS on live television and the Non-Watching (NW) group consisted of 18 patients who did not watch WCS. Heart rates, arrhythmia, and ischemic changes were evaluated. Results: There were no differences in the clinical characteristics, heart rates, premature atrial contraction frequencies, and ischemic changes between the two groups. Although there were no differences in total Premature Ventricular Contractions (PVCs), the frequency of PVCs during matches (61 ± 101 vs. 7 ± 8, P = 0.03) and 1 hour before matches (15 ± 17 vs. 3 ± 5, P = 0.01) were significantly higher in the W group than in the NW group. No sustained ventricular tachycardia or fibrillation was observed. Conclusions: A significant association between watching WCS and frequency of PVCs was observed in patients with/or suspected of having cardiovascular disease. Received Date: February 13, 2016 Accepted Date: March 28, 2016 Published Date: April 01, 2016 Citation: Shimada, K., et al. Watching National Team Matches in World Cup Soccer 2014 on Television was Associated with Increasing Frequency of Premature Ventricular Contractions. (2016) J Heart Cardiol 2(1): 17-21. DOI: 10.15436/2378-6914.16.022 Journal of Heart and Cardiology Open Access Review Article Copyrights:
Journal of Arrhythmia | 2013
Takashi Tokano; Yuji Nakazato; Tomoyuki Shiozawa; Hirokazu Konishi; Masaru Hiki; Yoshiteru Kato; Sayaka Komatsu; Miki Yamase; Kaoru Komatsu; Hidemori Hayashi; Gaku Sekita; Satoru Suwa; Fumiyasu Bito; Kyoko Kizu; Masataka Sumiyoshi; Hiroyuki Daida
Lead implantation using the cephalic vein (CV) cutdown technique has been well established, but is not always expected to achieve high success rates. We studied the relationship between preoperative CV venography and the success rate of lead implantation.
Cardiovascular Diabetology | 2016
Shuhei Takahashi; Kazunori Shimada; Katsumi Miyauchi; Tetsuro Miyazaki; Eiryu Sai; Manabu Ogita; Shuta Tsuboi; Hiroshi Tamura; Shinya Okazaki; Tomoyuki Shiozawa; Shohei Ouchi; Tatsuro Aikawa; Tomoyasu Kadoguchi; Hamad Al Shahi; Takuma Yoshihara; Makoto Hiki; Kikuo Isoda; Hiroyuki Daida