Keisei Kosaki

Arterial stiffness of lifelong Japanese female pearl divers

Japanese female pearl divers called Ama specialize in free diving in the cold sea for collecting foods and pearls in oysters. Exercising in the water combined with marked bradycardia and pressor responses provides a circulatory challenge to properly buffer or cushion elevated cardiac pulsations. Because Ama perform repeated free dives throughout their lives, it is possible that they may have adapted similar arterial structure and function to those seen in diving mammals. We compared arterial stiffness of lifelong Japanese pearl divers with age-matched physically inactive adults living in the same fishing villages. A total of 115 Japanese female pearl divers were studied. Additionally, 50 physically inactive adults as well as 33 physically active adults (participating in community fitness programs) living in the same coastal villages were also studied. There were no differences in age (∼65 yr), body mass index, and brachial blood pressure between the groups. Measures of arterial stiffness, cardio-ankle vascular index and β-stiffness index were lower (P < 0.05) in pearl divers and physically active adults than in their physically inactive peers. Augmentation pressure and augmentation index adjusted for the heart rate of 75 beats/min were lower (P < 0.05) in pearl divers than in other groups. These results indicate that lifelong Japanese pearl divers demonstrate reduced arterial stiffness and arterial wave reflection compared with age-matched physically inactive peers living in the same fishing villages.

Effect of habitual exercise on urinary liver-type fatty acid-binding protein levels in middle-aged and older adults.

The purpose of this study was to examine the effect of habitual exercise on urinary liver‐type fatty acid‐binding protein (L‐FABP), which can reflect the degree of various stresses on renal proximal tubule related to the progression of renal disease, in middle‐aged and older adults. Cross‐sectional and interventional approaches were used to comprehensively achieve this purpose. In the cross‐sectional study, we investigated the relationship between physical activity levels and urinary L‐FABP levels in 130 middle‐aged and older adults. In the interventional study, subjects (n=31) were divided into two groups: exercise (n=19) and control group (n=12), whereby we examined the effects of 12‐week aerobic exercise training on urinary L‐FABP levels. The cross‐sectional study showed that the urinary L‐FABP levels were significantly lower in the higher physical activity group than in the lower physical activity group (P<.05). In the interventional study, 12‐week aerobic exercise training significantly decreased urinary L‐FABP levels (P<.01). Furthermore, the relative changes in urinary L‐FABP levels were significantly correlated with the relative changes in physical activity levels and mean arterial pressure after intervention (r=−.374 and r=.530, respectively). Our results revealed that the urinary L‐FABP levels were lower in the higher physical activity individuals, and aerobic exercise training decreased urinary L‐FABP levels. These results suggest that habitual exercise appears to be associated with a decrease in the degree of several stresses on renal proximal tubule and to be beneficial for kidney health in middle‐aged and older adults.

Effects of aerobic and resistance training combined with fortified milk on muscle mass, muscle strength, and physical performance in older adults: A randomized controlled trial

ObjectivesFortified milk and resistance training (RT) increase muscle mass, muscle strength, and physical performance in older adults, but it remains unclear whether RT combined with aerobic training (AT) would have stronger effects on these outcomes. The purpose of this study was to examine the effects of aerobic and resistance training (ART) combined with fortified milk consumption on muscle mass, muscle strength, and physical performance in older adults.DesignOpen-labeled randomized controlled trial. Setting: University of Tsukuba.ParticipantsFifty-six older adults aged 65-79.InterventionParticipants were randomly allocated into resistance training (RT + fortified milk, n = 28) and aerobic and resistance training (ART + fortified milk, n = 28) groups. All participants attended supervised exercise programs twice a week at University of Tsukuba and ingested fortified milk every day for 12 weeks. Skeletal muscle index ([SMI]: appendicular lean mass/ height2) was assessed using dual-energy X-ray absorptiometry as a muscle mass measure. One-repetition maximum strength was measured using four kinds of resistance training machines (chest press, leg extension, leg curl, and leg press) as muscle strength measures. Sit-to-stand and arm curl tests were also assessed as physical performance measures.MeasurementsThe primary measurements were muscle mass and strength. The secondary outcomes were physical performance, blood samples, habitual diet, habitual physical activity, and medication use.ResultsAlthough the muscle strength and physical performance measures significantly improved in both groups, SMI significantly improved in only the RT group. There was no significant difference in the change in SMI and muscle strength measures between the two groups. However, the change in sit-to-stand and arm curl measures in the ART group were significantly higher than those in the RT group.ConclusionsThese results suggest that AT before RT combined with fortified milk consumption has similar effects on skeletal muscle mass and strength compared with RT alone, but it may be a more useful strategy to improve physical performance in older adults. Although the mechanism of our intervention is uncertain, our program would be an effective prevention for sarcopenia in older adults.

Association between muscular strength and intrarenal vascular resistance in middle-aged and older individuals

ABSTRACT A strategy for the preservation of intrarenal vasculature conditions remains obscure in middle‐aged and older individuals without the renal disease. In the present study, we sought to identify whether the maintenance of muscular strength is an effective method of preserving the intrarenal vasculature condition of middle‐aged and older individuals. Therefore, we applied a cross‐sectional approach for investigating the relationship between muscular strength and the condition of the intrarenal vasculature. In 169 middle‐aged and older individuals without renal disease, handgrip strength (HGS) and the renal resistive index (RRI) were measured as the parameters of muscular strength and intrarenal vascular resistance, respectively. The RRI was elevated with aging (rs = 0.499, P < 0.001) and was inversely correlated with HGS (rs = − 0.370, P < 0.001). The relationship between RRI and HGS remained significant after the consideration of confounders, including age and various central hemodynamic parameters. Furthermore, when the individuals were divided into four groups according to age (middle‐aged or older) and the median HGS values, the RRI exhibited the highest values in the older group with lower HGS values (P < 0.001). Our findings indicate that muscular strength as assessed by HGS is independently associated with the RRI (i.e. intrarenal vascular resistance) in middle‐aged and older individuals. This finding suggests that the muscular strength may be one of the key factors to preserve the intrarenal vasculature condition. HighlightsRenal resistive index increases with aging.Handgrip strength is independently associated with the renal resistive index.Muscular strength may be important to preserve intrarenal vasculature condition.

Aerobic exercise training enhances cerebrovascular pulsatility response to acute aerobic exercise in older adults

The brains low resistance ensures a robust blood flow throughout systole and diastole and is susceptible to flow pulsatility. Increased cerebral pulsatility contributes to the progression of cerebrovascular disease. Although aerobic exercise affects vascular function, little is known about the effect of exercise on the cerebral pulsatility index in older adults. The aim of this study was to investigate the effect of exercise training on the post‐exercise cerebral pulsatility response in older adults. Ten healthy older adults participated in a 12‐week exercise training intervention. Before and after the intervention, we measured the pulsatility index of the middle cerebral artery by means of transcranial Doppler method at baseline and following a cycling exercise bout performed at an intensity corresponding to the ventilatory threshold. Before exercise training, there was no significant change in the cerebral pulsatility response to an acute bout of cycling exercise. However, after the intervention, cerebral pulsatility decreased significantly following 30 min of an acute cycling exercise (P < 0.05). This study demonstrated that cerebral pulsatility index did not change following an acute bout of cycling exercise at an intensity corresponding to ventilatory threshold, but that, after 12 weeks of exercise training, cerebral pulsatility index was reduced at 30 min after a single bout of cycling exercise. These results suggest that long‐term aerobic exercise training may enhance the post‐exercise reduction in pulsatility index in older adults.

Lactotripeptide ingestion increases cerebral blood flow velocity in middle-aged and older adults

The age-related decrease in cerebral blood flow velocity increases the risk of cerebrovascular disease. Milk protein-derived bioactive peptides, e.g., lactotripeptide (LTP), have been shown to inhibit angiotensin converting enzyme activities and increase vasodilator production. We hypothesized that LTP ingestion increases cerebral blood flow velocity in middle-aged and older adults. In a randomized, placebo-controlled, double-blind design, 15 healthy middle-aged and older adults were assigned to either a LTP group or a placebo group. The subjects ingested LTP or placebo orally for 8 weeks. Before and after intervention, middle cerebral blood flow velocity was measured using transcranial Doppler ultrasonography. The baseline middle cerebral blood flow velocity and most other key dependent variables did not differ between the groups. LTP ingestion significantly increased middle cerebral blood flow velocity, but there was no such improvement in the placebo groups. We concluded that 8 weeks of LTP ingestion increased middle cerebral blood flow velocity in middle-aged and older adults.

Sexual Function Is an Indicator of Central Arterial Stiffness and Arterial Stiffness Gradient in Japanese Adult Men

Background As arterial stiffness increases in the absence of subjective symptoms, a personal indicator that reflects increased risk of cardiovascular disease is necessary. Penile erection is regulated by vascular function, and atherosclerosis affects the penile artery earlier than it affects the coronary and carotid arteries. Therefore, we hypothesized that deterioration of erectile function could be a marker of increased risk for cardiovascular disease. To test our hypothesis, we assessed erectile function and arterial stiffness in a cross‐sectional study. Methods and Results Carotid‐femoral pulse wave velocity (PWV), brachial‐ankle PWV, femoral‐ankle PWV, and arterial stiffness gradient (PWV ratio: carotid‐femoral PWV/femoral‐ankle PWV) were measured as indexes of central, systemic, and peripheral arterial stiffness and peripheral organ damage, respectively, in 317 adult men. In addition, erectile function was assessed by using the questionnaire International Index of Erectile Function 5 (a descending score indicates worsening of erectile function). The scores of male sexual function were inversely correlated with carotid‐femoral PWV (r s=−0.41), brachial‐ankle PWV (r s=−0.35), femoral‐ankle PWV (r s=−0.19), and PWV ratio (r s=−0.33). Furthermore, multivariate linear regression analyses revealed that International Index of Erectile Function 5 scores were significantly associated with carotid‐femoral PWV (β=−0.22) and PWV ratio (β=−0.25), but not with brachial‐ankle PWV and femoral‐ankle PWV. Conclusions Our results indicated that erectile function is independently associated with central arterial stiffness and peripheral organ damage. These findings suggest that male sexual function could be an easily identifiable and independent marker of increased central arterial stiffness and peripheral organ damage.

Habitual exercise decreases plasma xanthine oxidoreductase activity in middle-aged and older women

The aim of present study was to investigate the association between plasma xanthine oxidoreductase activity, which has gained attention as a novel preventive target of cardiovascular disease, and various physiological parameters and was to determine the effects of habitual exercise on plasma xanthine oxidoreductase activity in middle-aged and older women. In the cross-sectional study, we investigated the association between plasma xanthine oxidoreductase activity and various physiological parameters in 94 middle-aged and older women. In the interventional study, subjects (n = 22) were divided into two groups: exercise (n = 12) or the control group (n = 10), whereby we examined the effect of 12-week aerobic exercise training on plasma xanthine oxidoreductase activity in middle-aged and older women. The cross-sectional study demonstrated that plasma xanthine oxidoreductase activity was significantly associated with various physiological parameters, including visceral fat and daily step counts. In the interventional study, the plasma xanthine oxidoreductase activity significantly decreased after the 12-week aerobic exercise training, its changes were inversely associated with the changes in daily step counts. Our results revealed that the plasma xanthine oxidoreductase activity was associated with visceral fat accumulation and lack of exercise, and it was decreased by the aerobic exercise training.

Urinary liver-type fatty acid-binding protein is associated with subendocardial viability ratio in middle- and older-aged adults

ABSTRACT Background: To identify one of the physiological underlying mechanisms of the predictive effects of urinary liver-type fatty acid-binding protein (L-FABP) for the onset of cardiovascular disease (CVD), we investigated the relationship between urinary L-FABP levels and subendocardial viability ratio (SEVR), a marker of myocardial perfusion, in middle- and older-aged adults. Methods: This was a cross-sectional study of 249 middle- and older-aged adults (aged 46–83 years). We measured urinary L-FABP levels and central hemodynamic parameters, including SEVR, calculated by pulse wave analysis using an applanation tonometry. Results: In the participants stratified in accordance with the tertiles of urinary L-FABP levels, SEVR decreased in a stepwise fashion with increasing tertiles (p < 0.001). Furthermore, this association remains significant after the consideration of various confounders. On the contrary, urinary albumin levels were not independently related with SEVR. Conclusion: Our results demonstrated that urinary L-FABP levels were independently associated with the SEVR of the middle- and older-aged adults. This result suggests that the increase in urinary L-FABP levels even within the normal range might be related to the decrease in myocardial perfusion (SEVR).

Impact of Age and Aerobic Exercise Training on Conduit Artery Wall Thickness: Role of the Shear Pattern

Hemodynamic shear stress is the frictional force of blood on the arterial wall. The shear pattern in the conduit artery affects the endothelium and may participate in the development and progression of atherosclerosis. We investigated the role of the shear pattern in age- and aerobic exercise-induced changes in conduit artery wall thickness via cross-sectional and interventional studies. In a cross-sectional study, we found that brachial shear rate patterns and brachial artery intima-media thickness (IMT) correlated with age. Additionally, brachial artery shear rate patterns were associated with brachial artery IMT in 102 middle-aged and older individuals. In an interventional study, 39 middle-aged and older subjects were divided into 2 groups: control and exercise. The exercise group completed 12 weeks of aerobic exercise training. Aerobic exercise training significantly increased the antegrade shear rate and decreased the retrograde shear rate and brachial artery IMT. Moreover, changes in the brachial artery antegrade shear rate and the retrograde shear rate correlated with the change in brachial artery IMT. The results of the present study indicate that changes in brachial artery shear rate patterns may contribute to age- and aerobic exercise training-induced changes in brachial artery wall thickness.