To elucidate the effects of endurance training on circulating irisin levels in young and middle-aged/older adults, and to determine the association between endurance training-induced alteration of irisin and reduction in body fat. Twenty-five healthy young (age 21 ± 1 years; 16 men, 9 women) and 28 healthy middle-aged/older adults (age 67 ± 8 years; 12 men, 16 women) participated in the study. Each age cohort was divided into two groups: the endurance-training group (14 young, 14 middle-aged/older) and the control group. Subjects in the training groups completed an 8-week endurance-training program (cycling at 60-70% peak oxygen uptake [O2peak] for 45 min, 3 days/week). Before and after the intervention, we evaluated serum irisin level, O2peak, and body composition. The increase in O2peak in the young and middle-aged/older training groups after the intervention period was significantly greater than those in the young and middle-aged/older control groups (P < 0.05). Serum irisin level was significantly increased in the middle-aged/older training group after the intervention period (P < 0.01), but not in the young training group. Furthermore, in the middle-aged/older training group, the endurance training-induced reduction in visceral adipose tissue area was negatively correlated with the change in serum irisin level (r = −0.54, P < 0.05). These results suggest a possible role for secreted irisin in the exercise-induced alteration of abdominal visceral fat in middle-aged and older adults.

Temporal and spatial variation of the macrofaunal community was investigated in seagrass meadows in Akkeshi-ko estuary and coastal area of Akkeshi Bay, northern Japan. We specifically addressed the question of how the salinity gradient in seagrass meadows affects the species richness, abundance and similarity of faunal groups classified based on the degree of association with the seagrasses, i.e. highly motile species that drift in the water column among seagrass blades (drift-fauna, DF group) and less motile species that are tightly associated with seagrass substrates (seagrass-associated fauna, SA group).A total of 70 species were collected semi-quantitatively using an epibenthic sledge, among which more than one third of the species were captured in all areas, and a quarter of species only in the marine area. Significant spatial variation in species richness, as well as a positive relationship between salinity and species richness was found for most sampling occasions and for both functional groups. Whereas, relationship between salinity and abundance of macrofauna was not clear although significant time and site interactions were found for both functional groups. Patterns of similarity of assemblages varied between the functional groups: clear differences by sampling sites were discerned for DF group but not for SA group. These results provided evidence that the macrofaunal community structures in seagrass beds varied with the salinity gradient, but the pattern differed with time and between functional groups, possibly due to the effect of biotic and abiotic factors that also changed with salinity.

Fujie S, Hasegawa N, Sato K, Fujita S, Sanada K, Hamaoka T, Iemitsu M. Aerobic exercise training-induced changes in serum adropin level are associated with reduced arterial stiffness in middle-aged and older adults. Am J Physiol Heart Circ Physiol 309: H1642-H1647, 2015. First published September 14, 2015; doi:10.1152/ajpheart.00338.2015.-Aging-induced arterial stiffening is reduced by aerobic exercise training, and elevated production of nitric oxide (NO) participates in this effect. Adropin is a regulator of endothelial NO synthase and NO release, and circulating adropin level decreases with age. However, the effect of habitual aerobic exercise on circulating adropin levels in healthy middleaged and older adults remains unclear. We sought to determine whether serum adropin level is associated with exercise training-induced changes in arterial stiffness. First, in a cross-sectional study, we investigated the association between serum adropin level and both arterial stiffness and cardiorespiratory fitness in 80 healthy middle-aged and older subjects (65.6 Ϯ 0.9 yr). Second, in an intervention study, we examined the effects of 8-wk aerobic exercise training on serum adropin level and arterial stiffness in 40 healthy middle-aged and older subjects (67.3 Ϯ 1.0 yr) divided into two groups: aerobic exercise training and sedentary controls. In the cross-sectional study, serum adropin level was negatively correlated with carotid ␤-stiffness (r ϭ Ϫ0.437, P Ͻ 0.001) and positively correlated with plasma NOx level (r ϭ 0.493, P Ͻ 0.001) and cardiorespiratory fitness (r ϭ 0.457, P Ͻ 0.001). Serum adropin levels were elevated after the 8-wk aerobic exercise training intervention, and training-induced changes in serum adropin level were correlated with traininginduced changes in carotid ␤-stiffness (r ϭ Ϫ0.399, P Ͻ 0.05) and plasma NOx level (r ϭ 0.623, P Ͻ 0.001). Thus the increase in adropin may participate in the exercise-induced reduction of arterial stiffness. ARTERIAL STIFFNESS increases with age (26) owing to declines in endothelial function and autonomic function and increases in arterial wall thickness and calcification (1,3,4,11,18,24,26,31). This functional deterioration impairs the conduit and buffering functions of arteries, leading to several pathological conditions, including hypertension, atherosclerosis, and stroke (1,4,18,26). A cross-sectional study revealed that arterial stiffness was lower in individuals with higher levels of cardiorespiratory fitness (23, 28). Furthermore, habitual aerobic exercise reduces arterial stiffness (10, 28).Adropin consists of 76 amino acids and is encoded by a gene, Energy Homeostasis Associated (Enho) (16), and expressed in multiple tissues, including the brain, heart, kidney, liver, pancreas, skeletal muscle, and small intestine (2, 32). Circulating adropin level decreases with age (7). Recent work showed that adropin is expressed in vascular endothelial cells and promotes nitric oxide (NO) release by regulating endothelial nitric oxide synthase (eNOS) expression via vascul...

HIIT may reduce central arterial stiffness via the increase in aortic nitric oxide bioavailability despite it being done in a short time and short term and has the same effects as AT.

Aging-induced elevation in C1q secretion activates the Wnt signaling pathway in muscles, leading to the development of muscle fibrosis. However, the association between serum C1q level and muscle mass and strength remains unclear in humans. The aim of the study was to elucidate whether serum C1q level is associated with aging- and resistance training-induced changes in muscle mass and strength. First, in a cross-sectional study, we investigated the association between serum C1q level and muscle mass and strength in 131 healthy subjects, aged 20-81 yr. Second, in an intervention study, we examined the association between the effects of serum C1q level and muscle mass and strength on 12 wk resistance training in 11 healthy older adults (60-81 yr). In the cross-sectional study, serum C1q level increased with aging and was negatively correlated with muscle mass and strength. Furthermore, 12 wk resistance training in older adults reduced the age-associated elevation in serum C1q levels. The training effect of serum C1q level significantly correlated with the change in the cross-sectional area of the thigh (r = -0.703; P < 0.01). Serum C1q level may reflect loss of muscle mass; therefore, C1q may be a novel biomarker of sarcopenia.

Aging-induced deterioration of arterial stiffness is decreased by regular exercise, and increased nitric oxide (NO) production participates in this effect. Apelin regulates endothelial NO synthase in endothelial cells, promoting NO production. However, the effect of aerobic exercise training on circulating apelin levels in healthy middle-aged and older adults remains unknown. Accordingly, this study aimed to clarify the effects of regular aerobic exercise on apelin concentrations in middle-aged and older adults. Thirty-four healthy middle-aged and older subjects (67.0 ± 1.3 years) were randomly divided into two groups: exercise intervention and sedentary controls. Subjects in the training group completed 8-week of aerobic exercise training (60–70% peak oxygen uptake [VO2peak] for 45 min, 3 days/week). Before and after the intervention, we evaluated plasma apelin and nitrite/nitrate (NOx) concentrations, VO2peak, and arterial stiffness index. In the training group, VO2peak was significantly increased, and carotid β-stiffness was significantly decreased, after the intervention (P<0.05). Moreover, plasma apelin and NOx levels were significantly increased in the training group after the intervention (P<0.05). Additionally, there was a correlation between the training effects of plasma apelin levels and carotidβ-stiffness (r = −0.508, P = 0.032) and plasma NOx levels (r = 0.494, P = 0.037). By contrast, none of these parameters changed significantly in the control group. These results suggest that the increased in plasma apelin levels may be associated with exercise training-induced alternation of arterial stiffness in middle-aged and older adults.

These results suggest that chronic and sufficient repetition of muscle stretch stimulation may result in chronic high arterial compliance, although a single bout of stretch exercise acutely affects arterial compliance.

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