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Dive into the research topics where Asako Miyaki is active.

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Featured researches published by Asako Miyaki.


British Journal of Sports Medicine | 2009

Effect of 12 weeks of moderate–intensity resistance training on arterial stiffness: a randomised controlled trial in women aged 32–59 years

Mutsuko Yoshizawa; Seiji Maeda; Asako Miyaki; Maiko Misono; Yoko Saito; Kai Tanabe; Shinya Kuno; Ryuichi Ajisaka

Background: Resistance training has been increasingly incorporated into the overall exercise programme because of its effect on muscle strength, functional capacity and osteoporosis. High-intensity resistance training increases arterial stiffness. However, the effect of moderate-intensity resistance training on arterial stiffness is unknown. Objective: To determine whether 12 weeks of moderate-intensity resistance training increases arterial stiffness in middle-aged women. Methods: 35 middle-aged women (age range 32 to 59 years) volunteered to participate. The subjects were randomly assigned to one of three groups: resistance training (RT) group, aerobic exercise training (AET) group or control group. The RT and AET groups performed 12 weeks of moderate-intensity resistance training or aerobic exercise training (two days/week). Results: In the RT group, one-repetition maximum strength significantly increased after the intervention. Interestingly, aortic (carotid–femoral) pulse wave velocity (PWV; an index of arterial stiffness), and peripheral (femoral–ankle) PWV did not change with moderate-intensity resistance training. In contrast, in the AET group, carotid–femoral PWV significantly decreased after the intervention. Resistance training and aerobic exercise training did not affect blood pressure. Conclusions: This study found that moderate-intensity resistance training did not increase arterial stiffness in middle-aged women, which may have great importance for health promotion with resistance training.


Angiology | 2009

Effect of weight reduction with dietary intervention on arterial distensibility and endothelial function in obese men

Asako Miyaki; Seiji Maeda; Mutsuko Yoshizawa; Maiko Misono; Yoko Saito; Hiroyuki Sasai; Takayuki Endo; Yoshio Nakata; Kiyoji Tanaka; Ryuichi Ajisaka

Obesity and reduction in central arterial distensibility, respectively, have been identified as powerful and independent risk factors for cardiovascular disease. However, the effect of weight reduction on central arterial function in obese subjects has not yet been clarified. We investigated whether low-calorie diet-induced weight reduction affects central arterial distensibility and endothelial function in middle-aged obese men. Twelve obese men (age: 45+2 yrs, BMI: 30+1 kg/m 2) completed a 12-week dietary intervention. Caloric restriction induced significantly weight loss and decrease in BMI. After the program, carotid arterial compliance significantly increased and b-stiffness index and aortic pulse-wave velocity remarkably decreased. Concentrations of plasma endothelin-1 (ET-1) significantly decreased and plasma nitric oxide (NO) markedly increased after the program. Weight reduction by low-calorie diet in obese men increases central arterial distensibility, which may contribute to the improvement in endothelial function, as noted by a decrease in ET-1 and an increase in NO.


American Journal of Physiology-heart and Circulatory Physiology | 2009

Additive beneficial effects of lactotripeptides and aerobic exercise on arterial compliance in postmenopausal women

Mutsuko Yoshizawa; Seiji Maeda; Asako Miyaki; Maiko Misono; Youngju Choi; Nobutake Shimojo; Ryuichi Ajisaka; Hirofumi Tanaka

Central arterial compliance plays an important role in the functional abilities of the vasculature. Two active tripeptides, valine-proline-proline and isoleucine-proline-proline, were isolated from sour milk and were referred to as lactotripeptides (LTP). Because LTP appears to act as an angiotensin-converting enzyme inhibitor, it is plausible to hypothesize that LTP improves arterial compliance. We determined the effects of LTP ingestion alone or in combination with regular aerobic exercise on arterial compliance. A total of 55 postmenopausal women (50-65 yr old) were randomly divided into four groups: placebo, LTP, exercise and placebo (Ex + placebo), or exercise and LTP (Ex + LTP). LTP or placebo was administered orally for 8 wk. The exercise groups completed an 8-wk moderate aerobic exercise intervention. There were no differences in baseline arterial compliance and most other key dependent variables among the groups. Carotid arterial compliance increased significantly in the LTP (0.93 + or - 0.07 vs. 0.99 + or - 0.08 mm(2)/mmHg x 10(-1)), Ex + placebo (0.92 + or - 0.04 vs. 1.00 + or - 0.05 mm(2)/mmHg x 10(-1)), and Ex + LTP groups (0.86 + or - 0.06 vs. 1.00 + or - 0.06 mm(2)/mmHg x 10(-1)), whereas no such changes were observed in the placebo control group (0.86 + or - 0.06 vs. 0.85 + or - 0.07 mm(2)/mmHg x 10(-1)). The magnitude of increases in carotid arterial compliance was significantly greater in the Ex + LTP group (19 + or - 4%) than in other groups. The improvements in arterial compliance with LTP were associated with the corresponding reductions in arterial blood pressure and plasma angiotensin II concentrations. We concluded that LTP ingestion improves carotid arterial compliance and that the combination of LTP ingestion and regular exercise is additive and synergistic in improving arterial compliance in postmenopausal women.


Nutrition Research | 2012

Curcumin ingestion and exercise training improve vascular endothelial function in postmenopausal women.

Nobuhiko Akazawa; Youngju Choi; Asako Miyaki; Yoko Tanabe; Jun Sugawara; Ryuichi Ajisaka; Seiji Maeda

Vascular endothelial function is declines with aging and is associated with an increased risk of cardiovascular disease. Lifestyle modification, particularly aerobic exercise and dietary adjustment, has a favorable effect on vascular aging. Curcumin is a major component of turmeric with known anti-inflammatory and anti-oxidative effects. We investigated the effects of curcumin ingestion and aerobic exercise training on flow-mediated dilation as an indicator endothelial function in postmenopausal women. A total of 32 postmenopausal women were assigned to 3 groups: control, exercise, and curcumin groups. The curcumin group ingested curcumin orally for 8 weeks. The exercise group underwent moderate aerobic exercise training for 8 weeks. Before and after each intervention, flow-mediated dilation was measured. No difference in baseline flow-mediated dilation or other key dependent variables were detected among the groups. Flow-mediated dilation increased significantly and equally in the curcumin and exercise groups, whereas no changes were observed in the control group. Our results indicated that curcumin ingestion and aerobic exercise training can increase flow-mediated dilation in postmenopausal women, suggesting that both can potentially improve the age-related decline in endothelial function.


American Journal of Cardiology | 2009

Effect of Habitual Aerobic Exercise on Body Weight and Arterial Function in Overweight and Obese Men

Asako Miyaki; Seiji Maeda; Mutsuko Yoshizawa; Maiko Misono; Yoko Saito; Hiroyuki Sasai; Maeng-Kyu Kim; Yoshio Nakata; Kiyoji Tanaka; Ryuichi Ajisaka

The effect of habitual exercise on vascular function, including central arterial distensibility and endothelial function, in obese subjects has not yet been clarified. We investigated whether aerobic exercise training affects central arterial distensibility and endothelial function in middle-age overweight and obese men. A total of 21 overweight and obese men (age 50 +/- 2 years, body mass index 30 +/- 1 kg/m(2)) completed a 12-week aerobic exercise intervention. Aerobic exercise training significantly reduced their body weight and resulted in a significant decrease in body mass index. After the weight-reduction exercise program, carotid arterial compliance (determined by simultaneous B-mode ultrasonography and arterial applanation tonometry on the common carotid artery) significantly increased; and the beta-stiffness index, an index of arterial compliance adjusted for distending pressure, significantly decreased. The concentrations of plasma endothelin-1, a potent vasoconstrictor peptide produced by vascular endothelial cells, significantly decreased and plasma nitric oxide (measured as the stable end product [nitrite/nitrate]), a potent vasodilator produced by vascular endothelial cells, significantly increased after the weight-reduction exercise program. In conclusion, weight reduction by aerobic exercise training in overweight and obese men increased the central arterial distensibility. This increase might contribute to the improvement in endothelial function, as assessed by a decrease in endothelin-1 and an increase in nitric oxide, after exercise training-induced weight loss.


American Journal of Hypertension | 2010

Additive beneficial effects of lactotripeptides intake with regular exercise on endothelium-dependent dilatation in postmenopausal women.

Mutsuko Yoshizawa; Seiji Maeda; Asako Miyaki; Maiko Misono; Youngju Choi; Nobutake Shimojo; Ryuichi Ajisaka; Hirofumi Tanaka

BACKGROUND Peripheral conduit artery endothelium-dependent dilatation decreases with aging in humans. Lactotripeptides (LTPs) and regular exercise can improve endothelium-dependent dilatation, but combining these lifestyle modifications may be more effective than either treatment alone. We conducted a randomized, place-controlled trial with four different intervention arms. METHODS A total of 43 postmenopausal women (50-65 years old) were randomly divided into placebo, LTP, exercise and placebo (Ex+placebo), or exercise and LTP (Ex+LTP) groups. LTP or placebo was administered orally for 8 weeks. The exercise groups completed an 8-week moderate aerobic exercise (walking or cycling) intervention. RESULTS There were no statistically significant differences in baseline flow-mediated dilatation (FMD) and most other key dependent variables among the groups. FMD significantly increased in the LTP, Ex+placebo, and Ex+LTP groups whereas no such changes were observed in the placebo control group. The magnitude of increases in FMD was significantly greater in the Ex+LTP group than other intervention groups. CONCLUSION We concluded that LTP ingestion combined with regular aerobic exercise improves endothelium-dependent dilatation to a greater extent than monotherapy with either intervention alone in postmenopausal women.


American Journal of Physiology-heart and Circulatory Physiology | 2014

Aerobic exercise training increases plasma Klotho levels and reduces arterial stiffness in postmenopausal women

Tomoko Matsubara; Asako Miyaki; Nobuhiko Akazawa; Youngju Choi; Song-Gyu Ra; Koichiro Tanahashi; Hiroshi Kumagai; Satoshi Oikawa; Seiji Maeda

The Klotho gene is a suppressor of the aging phenomena, and the secretion as well as the circulation of Klotho proteins decrease with aging. Although habitual exercise has antiaging effects (e.g., a decrease in arterial stiffness), the relationship between Klotho and habitual exercise remains unclear. In the present study, we investigated the effect of habitual exercise on Klotho, with a particular focus on arterial stiffness. First, we examined the correlation between plasma Klotho concentration and arterial stiffness (carotid artery compliance and β-stiffness index) or aerobic exercise capacity [oxygen uptake at ventilatory threshold (VT)] in 69 healthy, postmenopausal women (50-76 years old) by conducting a cross-sectional study. Second, we tested the effects of aerobic exercise training on plasma Klotho concentrations and arterial stiffness. A total of 19 healthy, postmenopausal women (50-76 years old) were divided into two groups: control group and exercise group. The exercise group completed 12 wk of moderate aerobic exercise training. In the cross-sectional study, plasma Klotho concentrations positively correlated with carotid artery compliance and VT and negatively correlated with the β-stiffness index. In the interventional study, aerobic exercise training increased plasma Klotho concentrations and carotid artery compliance and decreased the β-stiffness index. Moreover, the changes in plasma Klotho concentration and arterial stiffness were found to be correlated. These results suggest a possible role for secreted Klotho in the exercise-induced modulation of arterial stiffness.


Applied Physiology, Nutrition, and Metabolism | 2012

Habitual aerobic exercise increases plasma pentraxin 3 levels in middle-aged and elderly women

Asako Miyaki; Seiji Maeda; Youngju Choi; Nobuhiko Akazawa; Yoko Tanabe; Ryuichi Ajisaka

Chronic inflammation that occurs with aging is one of the risk factors for cardiovascular disease. Regular exercise may prevent cardiovascular morbidity by decreasing chronic systematic inflammation. Additionally, excess inflammation can be reduced by the anti-inflammatory protein pentraxin 3 (PTX3). Thus, both habitual exercise and PTX3 have an anti-inflammatory effect. However, it is unclear whether regular exercise leads to increased plasma PTX3 concentration. In the present study, we investigated the effects of regular aerobic exercise on plasma PTX3 concentration in middle-aged and elderly women. Twenty-two postmenopausal women (60 ± 6 years) were randomly divided evenly into 2 groups (i.e., exercise intervention and control). Subjects in the exercise group completed 2 months of regular aerobic exercise training (walking and cycling, 30-45 min, 3-5 days·week⁻¹). Before and after the intervention, we evaluated plasma PTX3 concentration, peak oxygen uptake, blood chemistry, and arterial distensibility (carotid arterial compliance and β-stiffness) in all participants. There were no significant differences in baseline parameters between the 2 groups. Plasma PTX3 concentration was significantly increased in the exercise group after the intervention (p < 0.05). High-density lipoprotein cholesterol, peak oxygen uptake, and arterial compliance were also significantly increased (p < 0.05), while β-stiffness was markedly decreased (p < 0.01) after the intervention. On the other hand, there was no change in the parameters tested in the control group. This study demonstrates that regular aerobic exercise increases plasma PTX3 concentration with improvement of high-density lipoprotein cholesterol, peak oxygen uptake, and arterial distensibility in postmenopausal women.


American Journal of Hypertension | 2013

Association of plasma pentraxin 3 with arterial stiffness in overweight and obese individuals.

Asako Miyaki; Seiji Maeda; Youngju Choi; Nobuhiko Akazawa; Miki Eto; Kiyoji Tanaka; Ryuichi Ajisaka

BACKGROUND Obesity and increased arterial stiffness are independent risk factors for cardiovascular disease. The degree of arterial stiffness in obese individuals is greater than that in normal-weight subjects. Pentraxin 3 (PTX3) is mainly produced by vascular tissues and exerts a cardioprotective effect. However, the relationship between PTX3 and arterial stiffness in obese individuals has not yet been clarified. In this study, we examined the relationships between obesity, arterial stiffness, and PTX3 levels in 282 subjects. METHODS All participants were classified as normal weight, overweight, or obese on the basis of their body mass index. We measured the brachial-ankle pulse wave velocity (baPWV; an index of arterial stiffness) and plasma PTX3 concentrations in all subjects. Additionally, the carotid-femoral PWV (cfPWV) was measured in 173 subjects. RESULTS We found that baPWV and cfPWV in overweight and obese subjects were significantly higher than those in normal-weight subjects. Plasma PTX3 concentrations in normal-weight subjects were significantly higher than those in overweight and obese subjects. Moreover, PTX3 had a significant negative correlation with baPWV. However, stepwise multivariable linear regression analysis did not indicate any associations between these parameters. CONCLUSIONS Arterial stiffness is increased in overweight and obese individuals. The increase in arterial stiffness may, at least in part, be associated with an obesity-related reduction in plasma PTX3 concentrations.


Medicine and Science in Sports and Exercise | 2011

Plasma Pentraxin 3 Concentration Increases in Endurance-Trained Men

Asako Miyaki; Seiji Maeda; Takeshi Otsuki; Ryuichi Ajisaka

INTRODUCTION Pentraxin 3 (PTX3), which is mainly produced by endothelial cells, macrophages, and smooth muscle cells in the atherosclerotic region, has a cardioprotective effect. Endurance exercise training has also been known to offer cardioprotection. However, the effect of regular endurance exercise on PTX3 is unknown. This study aimed to investigate whether plasma PTX3 concentrations increase in endurance-trained men. Ten young endurance-trained men and 12 age- and gender-matched sedentary controls participated in this study. METHODS We measured plasma PTX3 concentrations of the participants in each group. We also determined systemic arterial compliance (SAC) by using simultaneous M-mode ultrasound and arterial applanation tonometry of the common carotid artery and used HDL cholesterol (HDLC) as an index of cardioprotective effect. RESULTS Maximal oxygen uptake was significantly higher in the endurance-trained men than that in the sedentary controls. SAC and HDLC were significantly higher in the endurance-trained men than that in the sedentary controls (SAC = 1.74 ± 0.11 vs 1.41 ± 0.09 mL·mm Hg(-1), P < 0.05; HDLC = 70 ± 5 vs 57 ± 4 mg·dL(-1), P < 0.05). Plasma PTX3 concentrations were markedly higher in the endurance-trained men than that in the sedentary controls (0.93 ± 0.11 vs 0.68 ± 0.06 ng·mL(-1), P < 0.05). Relationships between plasma PTX3 concentrations and SAC and HDLC were linear. CONCLUSIONS This is the first study revealing that endurance-trained individuals had higher levels of circulating PTX3 than sedentary controls. PTX3 may play a partial role in endurance exercise training-induced cardioprotection.

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