Abstract P319: Salusin-α is a Novel Biomarker of Cardiovascular Disease Risk in Aging and Exercise Lifestyle: Cross-Sectional and Intervention Study

Abstract

Introduction: A physically active lifestyle leads to reduced risks of cardiovascular disease events in the elderly. A level of circulating salusin-α is a novel biomarker of cardiovascular disease and is associated with increased arterial stiffness. Indeed, circulating levels of salusin-α are lower in patients with coronary arterial disease and hypertension compared to healthy subjects. However, it is unknown whether circulating salusin-α levels are decreased with advanced age and whether circulating salusin-α levels are associated with the reduced cardiovascular disease risks by exercise lifestyle. Hypothesis: We assessed the hypothesis that salusin-α is involved to the changes in cardiovascular disease risk by aging or exercise-promoting healthy lifestyle. Methods: In Experiment 1, 105 healthy subjects (20-80 years old) participated in a cross-sectional study. The subjects were divided into 2 groups: young (under 40 years, n=45) versus middle-age and older (over 40 years, n=60). In Experiment 2, 36 young subjects (young aerobic exercise training group; Young-AT: n=27 and control group; Young-Con: n=9) and 40 healthy middle-age and older subjects (middle-age and older aerobic exercise training group; Middle-age and older-AT: n=26 and control group; Middle-age and older-Con: n=14) volunteered to participate. Subjects in AT groups completed eight weeks of habitual aerobic exercise (60-70% peak oxygen uptake [VO2peak] for 45 min, 3 days/week). We measured serum salusin-α level, carotid-femoral pulse wave velocity (cfPWV), brachial artery systolic (SBP) and diastolic (DBP) blood pressures, common carotid intima-media thickness (ccIMT) and VO2peak. Results: In the cross-sectional study, cfPWV, SBP, DBP and ccIMT were significantly higher and serum salusin-α levels were significantly lower in the middle-age and older adults compared to young adults. Negative correlations were observed between serum salusin-α levels and age (r=–0.698, P<0.01), SBP (r=–0.458, P<0.01), DBP (r=–0.473, P<0.01), cfPWV (r=–0.479, P<0.01), and ccIMT (r=–0.577, P<0.01). In the exercise intervention study, VO2peak and serum salusin-α levels were significantly increased, and cfPWV, SBP and DBP were significantly lowered in the Middle-age and older-AT group compared to the Con group (each P<0.05). Additionally, significant negative correlations between exercise-induced changes in serum salusin-α levels and cfPWV (r=-0.597, P<0.01), SBP (r=–0.591, P<0.01), DBP (r=–0.442, P<0.05) or ccIMT (r=–0.484, P<0.05) were observed in the Middle-age and older-AT group. There were no significant differences for any of the parameters between Young-AT and Con groups. Conclusions: Changes in salusin-α levels may be a novel biomarker of the increase in cardiovascular disease risks with age and the decrease in cardiovascular disease risks with exercise lifestyle in healthy middle-age and older adults.