Relationship Between Arterial Stiffness and Athletic Training Programs in Young Adult Men

BackgroundWe examined the relationships of endurance and strength exercise training and the adolescent duration of training to arterial stiffness in young adult men. We hypothesized that young adults participating in endurance sports would have decreased arterial stiffness, whereas those in strength-based sports would have increased arterial stiffness. In addition, we predicted that these trends would be more pronounced with an increase in the duration of sport participation.MethodsSubjects were male endurance-trained men with short (current age, 20 years; age at beginning of competitive sport, 15 years; sport careers, 5 years; n = 7, S-ET) and long (current age, 20 years; age at beginning of competitive sport, 12 years; sport careers, 8 years; n = 7, L-ET) competitive sport careers, strength-trained men with short (current age, 20 years; age at beginning of competitive sport, 16 years; sport careers, 4 years; n = 7, S-ST) and long (current age, 22 years; age at beginning of competitive sport, 15 years; sport careers, 7 years; n = 7, L-ST) careers, and sedentary control men (aged, 20 years; n = 7, C).ResultsThe exercise training was associated with aortic pulse wave velocity (PWV), a traditional index of arterial stiffness, and the associations were statistically independent of blood pressure (BP). Aortic PWV was lower in L-ET than C and ST. Aortic PWV in L-ST was greater than that of C. The associations of exercise training with systemic arterial compliance (SAC), which inversely correlates with arterial stiffness, were also positive and BP independent. The SAC was greater in the ET groups compared with C and ST groups. The SAC in L-ST was lower than in C.ConclusionsThese results suggest that changes in arterial stiffness associated with different training programs appear in young adults as well as in older humans, and these changes may begin in adolescence

ACTN3 Polymorphism Affects Thigh Muscle Area

Muscle mass is an important factor influencing the activity of daily living in older adults. We aimed to investigate whether α-actinin-3 (ACTN3) gene R577X polymorphism affects muscle mass in older Japanese women. A total of 109 women (mean±SD, 64.1±6.0 years) were genotyped for the R/X variant of ACTN3. Mid-thigh muscle cross-sectional area (CSA) was assessed using MRI and compared using analysis of covariance models adjusted for body weight. In addition, physical activity and protein intake were measured as the living environmental factors affecting muscle mass. The ACTN3 R577X genotype distributions of the subjects were 19, 63 and 27 for the RR, RX, and XX genotypes, respectively. No differences in physical activity and protein intake were observed among the genotypes. The XX genotype showed lower thigh muscle CSA compared with RR&RX genotype (mean±SEM; XX: 69.1±1.8 cm2, RR&RX: 73.6±1.1 cm2; p<0.05). The results of the present study suggest that ACTN3 R577X polymorphism influences muscle mass in older Japanese women

Arterial Stiffness, Physical Activity, and Atrial Natriuretic Peptide Gene Polymorphism in Older Subjects

An increase in arterial stiffness with advancing age is associated with several pathological states, includinghypertension and arteriosclerosis. Regular exercise improves the aging-induced increase in arterial stiffnessand has a protective effect against these diseases. However, not all individuals respond to exerciseto the same extent. Atrial natriuretic peptide (ANP) is involved in the regulation of basal blood pressure,blood flow, and vascular tone. The present study was designed to clarify whether gene polymorphisms inANP-related genes affect exercise-induced improvements in arterial stiffness. We performed a cross-sectionalstudy of 291 healthy middle-aged and older Japanese subjects (63±1 years), examining the relationshipbetween daily physical activity–induced improvements in arterial stiffness, estimated by brachial-anklearterial pulse wave velocity (baPWV), and the gene polymorphisms of valine32methionine (V32M: 664G>A)in exon 1 of ANP and asparagine521aspartic acid (N521D: 1780A>G) in exon 8 of the ANP clearance receptor(NPR-C). The baseline baPWV was significantly lower in the active group, but no differences were seen inblood pressure. Active subjects with the ANP-VV genotype had significantly lower baPWV and higherplasma ANP levels compared with inactive subjects, but there were no variations related to the VM+MMgenotype. Additionally, baPWV and plasma ANP levels were negatively correlated in ANP-VV genotypesubjects, but were not correlated in VM+MM individuals. Our results suggest that ANP polymorphismin older Japanese subjects may affect the cardiovascular response to regular exercise

Mechanisms of exercise-induced improvements in the contractile apparatus of the mammalian myocardium

One of the main outcomes of aerobic endurance exercise training is the improved maximal oxygen uptake, and this is pivotal to the improved work capacity that follows the exercise training. Improved maximal oxygen uptake in turn is at least partly achieved because exercise training increases the ability of the myocardium to produce a greater cardiac output. In healthy subjects, this has been demonstrated repeatedly over many decades. It has recently emerged that this scenario may also be true under conditions of an initial myocardial dysfunction. For instance, myocardial improvements may still be observed after exercise training in post-myocardial infarction heart failure. In both health and disease, it is the changes that occur in the individual cardiomyocytes with respect to their ability to contract that by and large drive the exercise training-induced adaptation to the heart. Here, we review the evidence and the mechanisms by which exercise training induces beneficial changes in the mammalian myocardium, as obtained by means of experimental and clinical studies, and argue that these changes ultimately alter the function of the whole heart and contribute to the changes in whole-body function

DHEA Administration Activates Local Bioactive Androgen Metabolism in Cancellous Site of Tibia of Ovariectomized Rats

It is not known whether local androgen metabolism is involved in the mechanisms underlying the dehydroepiandrosterone (DHEA) administration-induced improvement of bone mineral density (BMD) in an estrogen-deficiency state. The aim of the present study was to clarify whether DHEA administration would improve local androgen metabolism and BMD in cancellous site of tibia of ovariectomized (OVX) rats. Twenty-two female rats, 6 weeks old, were randomized into three groups: sham-operated rats, OVX control rats, and OVX rats that received DHEA treatment. DHEA was administered intraperitoneally at 20 mg/kg body weight for 8 weeks. The concentrations of free testosterone and dihydrotestosterone (DHT) in cancellous site of tibia did not change as a result of ovariectomy, while the DHT concentration increased following DHEA administration. We revealed that DHEA administration improved the reduction of 17β- and 3β-hydroxysteroid dehydrogenases and clearly reversed the reduction of 5α-reductase types 1 and 2 and androgen receptor in the cancellous site of tibia of OVX rats. DHEA administration suppressed estrogen deficiency relative to the decrease in the cancellous BMD, which was positively associated with local DHT concentration. These findings indicate that DHEA administration enhances local bioactive androgen metabolism in the cancellous tibia of young OVX rats, suggesting that local DHT may play a part in the DHEA administration-induced improvement of cancellous BMD

Comparison between clinical significance of height-adjusted and weight-adjusted appendicular skeletal muscle mass

BACKGROUND: This study aimed to compare relationships between height- or weight-adjusted appendicular skeletal muscle mass (ASM/Ht(2) or ASM/Wt) and risk factors for cardiometabolic diseases or osteoporosis in Japanese men and women. METHODS: Subjects were healthy Japanese men (n = 583) and women (n = 1218). The study population included a young group (310 men and 357 women; age, 18–40 years) and a middle-aged and elderly group (273 men and 861 women; age, ≥41 years). ASM was measured by dual-energy X-ray absorptiometry. The reference values for class 1 and 2 sarcopenia in each sex were defined as values one and two standard deviations below the sex-specific means of the young group, respectively. RESULTS: The reference values for class 1 and 2 sarcopenia defined by ASM/Ht(2) were 7.77 and 6.89 kg/m(2) in men and 6.06 and 5.31 kg/m(2) in women, respectively. The reference values for ASM/Wt were 35.0 and 32.0% in men and 29.6 and 26.4% in women, respectively. In both men and women, ASM/Wt was negatively correlated with higher triglycerides (TG) and positively correlated with serum high-density lipoprotein cholesterol (HDL-C), but these associations were not found in height-adjusted ASM. In women, TG, systolic blood pressure, and diastolic blood pressure in sarcopenia defined by ASM/Wt were significantly higher than those in normal subjects, but these associations were not found in sarcopenia defined by ASM/Ht(2). Whole-body and regional bone mineral density in sarcopenia defined by ASM/Ht(2) were significantly lower than those in normal subjects, but these associations were not found in sarcopenia defined by ASM/Wt. CONCLUSIONS: Weight-adjusted definition was able to identify cardiometabolic risk factors such as TG and HDL-C while height-adjusted definition could identify factors for osteoporosis

DHEA administration and exercise training improves insulin resistance in obese rats

Background: Dehydroepiandrosterone (DHEA) is precursor of sex steroid hormone. We demonstrated that acute DHEA injection to type 1 diabetes model rats induced improvement of hyperglycemia. However, the effect of the combination of DHEA administration and exercise training on insulin resistance is still unclear. This study was undertaken to determine whether 6-weeks of DHEA administration and/or exercise training improve insulin resistance in obese male rats. Methods: After 14 weeks of a high-sucrose diet, obese male Wistar rats were assigned randomly to one of four groups: control, DHEA administration, exercise training, and a combination of DHEA administration and exercise training (n = 10 each group). Results: After 6-weeks of DHEA administration and/or exercise training, rats in the combination group weighed significantly less and had lower serum insulin levels than rats in the other groups. Moreover, the rats treated with DHEA alone or DHEA and exercise had significantly lower fasting glucose levels (combination, 84 ± 6.5 mg/dL; DHEA, 102 ± 9.5 mg/dL; control, 148 ± 10.5 mg/dL). In addition, insulin sensitivity check index showed significant improvements in the combination group (combination, 0.347 ± 0.11; exercise, 0.337 ± 0.16%; DHEA, 0.331 ± 0.14; control, 0.308 ± 0.12). Muscular DHEA and 5α-dihydrotestosterone (DHT) concentrations were significantly higher in the combination group, and closely correlated with the quantitative insulin-sensitivity check index (DHEA: r = 0.71, p < 0.01; DHT: r = 0.69, p < 0.01). Conclusion: These results showed that a combination of DHEA administration and exercise training effectively improved fasting blood glucose and insulin levels, and insulin sensitivity, which may reflect increased muscular DHEA and DHT concentrations

健康長寿の実現に向けた基盤的測定技術開発 ： ステロイドホルモンのLC-MS/MSスクリーニングアッセイ

departmental bulletin pape