title: Reduction of arterial stiffness by exercise training is associated with increasing plasma apelin level in middle-aged and older adults.
abstract: 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.
authors.affiliation: Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
authors.forename: Shumpei
authors.initials: S
authors.lastname: Fujie
authors.affiliation: Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Sato
authors.affiliation: Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
authors.forename: Eri
authors.initials: E
authors.lastname: Miyamoto-Mikami
authors.affiliation: Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
authors.forename: Natsuki
authors.initials: N
authors.lastname: Hasegawa
authors.affiliation: Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Fujita
authors.affiliation: Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Sanada
authors.affiliation: Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Hamaoka
authors.affiliation: Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
authors.forename: Motoyuki
authors.initials: M
authors.lastname: Iemitsu
mesh_terms: D000368:Aged; D000375:Aging / Q000097:blood / Q000473:pathology*; D000073861:Apelin; D002339:Carotid Arteries / Q000473:pathology; D005081:Exercise Therapy; D005260:Female; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000097:blood* / Q000235:genetics; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000096:biosynthesis / Q000097:blood; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000378:metabolism; D010101:Oxygen Consumption; D057185:Sedentary Behavior; D059289:Vascular Stiffness / Q000235:genetics*
chemical_list: C115436:APLN protein, human; D000073861:Apelin; D036341:Intercellular Signaling Peptides and Proteins; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase