Tetsuro Miyazaki

Dr. Tetsuro Miyazaki


Research Focus & Metrics

Academic Career Length

23Years (2004-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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10 September 2011 in Cardiovascular Diabetology
Verified
Journal Article
Open access
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KFKosuke FUKAO
Kosuke FUKAO
KSKazunori Shimada
Kazunori Shimada
MHMakoto Hiki
Makoto Hiki
TKTakashi Kiyanagi
Takashi Kiyanagi
KHKuniaki Hirose
Kuniaki Hirose
HDHiroyuki Daida
Hiroyuki Daida
Background: Hypertension is associated with impaired glucose tolerance and insulin resistance. Medical treatment that interferes with various steps in the renin-angiotensin system improves glucose tolerance and insulin resistance. However, it remains unclear if long-acting calcium channel blockers (CCBs) such as azelnidipine and amlodipine affect glucose tolerance and insulin resistance in clinical practice. Methods: Seventeen non-diabetic patients with essential hypertension who had controlled blood pressure levels using amlodipine (5 mg/day) were enrolled in this study. After randomization, either azelnidipine (16 mg/day) or amlodipine (5 mg/day) was administered in a crossover design for 12-weeks. At baseline and the end of each CCB therapy, samples of blood and urine were collected and 75 g oral glucose tolerance test (OGTT) was performed. In addition, hematopoietic progenitor cells (HPCs) were measured at each point by flow cytometry and endothelial functions were measured by fingertip pulse amplitude tonometry using EndoPAT. Results: Although blood pressure levels were identical after each CCB treatment, the heart rate significantly decreased after azelnidipine administration than that after amlodipine administration (P < 0.005). Compared with amlodipine administration, azelnidipine significantly decreased levels of glucose and insulin 120 min after the 75 g OGTT (both P < 0.05). Serum levels of high-sensitivity C-reactive protein (P = 0.067) and interleukin-6 (P = 0.035) were decreased. Although endothelial functions were not different between the two medication groups, the number of circulating HPCs was significantly increased after azelnidipine administration (P = 0.016). Conclusions: These results suggest that azelnidipine treatment may have beneficial effects on glucose tolerance, insulin sensitivity, the inflammatory state, and number of circulating progenitor cells in non-diabetic patients with essential hypertension.

27 February 2013 in Cardiovascular Diabetology
Verified
Journal Article
Open access
PDF file
RIRyoko Ichikawa
Ryoko Ichikawa
MDMasao Daimon
Masao Daimon
TMTetsuro Miyazaki
Tetsuro Miyazaki
TKTakayuki Kawata
Takayuki Kawata
SMSakiko Miyazaki
Sakiko Miyazaki
HDHiroyuki Daida
Hiroyuki Daida
Background: We hypothesized that clinical factors other than glycemic control may influence abnormal cardiac function in patients with type 2 diabetes mellitus (T2DM). We aimed to investigate the independent factors for abnormal cardiac function among clinical factors in T2DM.Methods: We studied 148 asymptomatic patients with T2DM without overt heart disease. Echocardiographic findings were compared between diabetic patients and 68 age-matched healthy subjects. Early (E) and late (A) diastolic mitral flow velocity and early diastolic mitral annular velocity (e’) were measured for assessing left ventricular (LV) diastolic function. We evaluated insulin resistance, non-esterified fatty acid, high-sensitive CRP, estimated glomerular filtration rate, waist/hip ratio, abdominal visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT) and other clinical characteristics in addition to glycemic control. VAT and SAT were quantified by computed tomography.Results: In T2DM, E/A and e’ were significantly lower, and E/e’, left atrial volume and LV mass were significantly greater than in control subjects. In multivariate liner regression analysis, VAT was an independent determinant of left atrial volume (β =0.203, p=0.011), E/A (β =−0.208, p=0.002), e’ (β =−0.354, p<0.001) and E/e’ (β=0.220, p=0.003). Age was also an independent determinant, whereas fasting plasma glucose and hemoglobin A1c levels were not. In addition to systolic blood pressure, waist-hip ratio (β=0.173, p=0.024) and VAT/SAT ratio (β=0.162, p=0.049) were independent determinants of LV mass.Conclusion: Excessive visceral fat accompanied by adipocyte dysfunction may play a greater role than glycemic control in the development of diastolic dysfunction and LV hypertrophy in T2DM.

21 November 2017 in Cardiovascular Diabetology
Verified
Journal Article
Open access
PDF file
SOShohei Ouchi
Shohei Ouchi
KSKazunori Shimada
Kazunori Shimada
TMTetsuro Miyazaki
Tetsuro Miyazaki
STShuhei Takahashi
Shuhei Takahashi
YSYurina Sugita-Yamaguchi
Yurina Sugita-Yamaguchi
HDHiroyuki Daida
Hiroyuki Daida
Diabetes mellitus is considered an important risk factor for cardiovascular diseases. High hemoglobin A1c (HbA1c) levels, which indicate poor glycemic control, have been associated with occurrence of cardiovascular diseases. There are few parameters which can predict cardiovascular risk in patients with well-controlled diabetes. Low 1,5-anhydroglucitol (1,5-AG) levels are considered a clinical marker of postprandial hyperglycemia. We hypothesized that low 1,5-AG levels could predict long-term mortality in acute coronary syndrome (ACS) patients with relatively low HbA1c levels. The present study followed a retrospective observational study design. We enrolled 388 consecutive patients with ACS admitted to the cardiac intensive care unit at the Juntendo University Hospital from January 2011 to December 2013. Levels of 1,5-AG were measured immediately before emergency coronary angiography. Patients with early stent thrombosis, no significant coronary artery stenosis, malignancy, liver cirrhosis, a history of gastrectomy, current steroid treatment, moderately to severely reduced kidney function (estimated glomerular filtration rate < 45 ml/min/1.73 m2; chronic kidney disease stage 3B, 4, and 5), HbA1c levels ≥ 7.0%, and those who received sodium glucose co-transporter 2 inhibitor therapy were excluded. During the 46.9-month mean follow-up period, nine patients (4.5%) died of cardiovascular disease. The 1,5-AG level was significantly lower in the cardiac death group compared with that in the survivor group (12.3 ± 5.3 vs. 19.2 ± 7.7 µg/ml, p < 0.01). Kaplan–Meier survival analysis showed that low 1,5-AG levels were associated with cardiac mortality (p = 0.02). Multivariable Cox regression analysis showed that 1,5-AG levels were an independent predictor of cardiac mortality (hazard ratio 0.76; 95% confidence interval 0.41–0.98; p = 0.03). Low 1,5-AG levels, which indicate postprandial hyperglycemia, predict long-term cardiac mortality even in ACS patients with HbA1c levels < 7.0%.

1 November 2014 in Journal of Cardiology
Verified
Journal Article
Closed access
HMHiroshi Masuda
Hiroshi Masuda
TMTetsuro Miyazaki
Tetsuro Miyazaki
KSKazunori Shimada
Kazunori Shimada
NTNaoto Tamura
Naoto Tamura
RMRan Matsudaira
Ran Matsudaira
HDHiroyuki Daida
Hiroyuki Daida

8 November 2018 in Nutrients
Verified
Journal Article
Open access
PDF file
YSYurina Sugita-Yamaguchi
Yurina Sugita-Yamaguchi
TMTetsuro Miyazaki
Tetsuro Miyazaki
KSKazunori Shimada
Kazunori Shimada
MSMegumi Shimizu
Megumi Shimizu
MKMitsuhiro Kunimoto
Mitsuhiro Kunimoto
HDHiroyuki Daida
Hiroyuki Daida
Background: Delirium is a common occurrence in patients admitted to the intensive care unit and is related to mortality and morbidity. Malnutrition is a predisposing factor for the development of delirium. Nevertheless, whether the nutritional status on admission anticipates the development of delirium in patients with acute cardiovascular diseases remains unknown. Objective: This study aims to assess the correlation between the nutritional status on admission using the nutritional index and the development of delirium in the coronary intensive care unit. Design: We examined 653 consecutive patients (mean age: 70 ± 14 years) admitted to the coronary intensive care unit of Juntendo University Hospital between January 2015 and December 2016. We evaluated three nutritional indices frequently used to assess the nutritional status, i.e., Geriatric Nutritional Risk Index (GNRI), Prognostic Nutritional Index (PNI), and Controlling Nutritional Status (CONUT). We defined delirium as patients with a delirium score >4 using the Intensive Care Delirium Screening Checklist. Results: Delirium was present in 58 patients. All nutritional indices exhibited a tendency for malnutrition in the delirium group compared with the non-delirium group (GNRI, 86.5 ± 9.38 versus 91.6 ± 9.89; PNI, 36.4 ± 6.95 versus 41.6 ± 7.62; CONUT, 5.88 ± 3.00 versus 3.61 ± 2.56; for all, p < 0.001). Furthermore, the maximum delirium score increased progressively from the low- to the high-risk group, as evaluated by each nutritional index (GNRI, PNI, CONUT; for all, p < 0.001). A multivariate analysis revealed that the PNI and CONUT were independent risk factors for the occurrence of delirium. Conclusions: A marked correlation exists between the nutritional index on admission, especially PNI and CONUT, and the development of delirium in patients with acute cardiovascular diseases, suggesting that malnutrition assessment upon admission could help identify patients at high risk of developing delirium.

28 November 2008 in Lipids in Health and Disease
Verified
Journal Article
Open access
PDF file
NYNaotake Yanagisawa
Naotake Yanagisawa
KSKazunori Shimada
Kazunori Shimada
TMTetsuro Miyazaki
Tetsuro Miyazaki
AKAtsumi Kume
Atsumi Kume
YKYohei Kitamura
Yohei Kitamura
HDHiroyuki Daida
Hiroyuki Daida
Deterioration of peroxisomal β-oxidation activity causes an accumulation of very long chain saturated fatty acids (VLCSFA) in various organs. We have recently reported that the levels of VLCSFA in the plasma and/or membranes of blood cells were significantly higher in patients with metabolic syndrome and in patients with coronary artery disease than the controls. The aim of the present study is to investigate the effect of VLCSFA accumulation on inflammatory and oxidative responses in VLCSFA-accumulated macrophages derived from X-linked adrenoleukodystrophy (X-ALD) protein (ALDP)-deficient mice. Elevated levels of VLCSFA were confirmed in macrophages from ALDP-deficient mice. The levels of nitric oxide (NO) production stimulated by lipopolysaccharide (LPS) and interferon-γ (IFN-γ), intracellular reactive oxygen species (ROS), and pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interluekin-6 (IL-6), and interleukin-12p70 (IL-12p70), were significantly higher in macrophages from ALDP-deficient mice than in those from wild-type mice. The inducible NO synthase (iNOS) mRNA expression also showed an increase in macrophages from ALDP-deficient mice. These results suggested that VLCSFA accumulation in macrophages may contribute to the pathogenesis of inflammatory diseases through the enhancement of inflammatory and oxidative responses.