Michael Sagiv

The ACE deletion allele is associated with Israeli elite endurance athletes

An Alu insertion (I)/deletion (D) polymorphism in the angiotensin I converting enzyme (ACE) gene has been associated with ACE activity. Opposing effects on elite athletic performance have been proposed for the I and D alleles; while the D allele favours improved endurance ability, the I allele promotes more power‐orientated events. We tested this hypothesis by determining the frequency of ACE ID alleles amongst 121 Israeli top‐level athletes classified by their sporting discipline (marathon runners or sprinters). Genotyping for ACE ID was performed using polymerase chain reaction on DNA from leucocytes. The ACE genotype and allele frequencies were compared with those of 247 healthy individuals. Allele and genotype frequencies differed significantly between the groups. The frequency of the D allele was 0.77 in the marathon runners, 0.66 in the control subjects (P= 0.01) and 0.57 in the sprinters (P= 0.002). The ACE DD genotype was more prevalent among the endurance athletes (0.62) than among the control subjects (0.43, P= 0.004) and the power athletes (0.34, P= 0.004). In the group of elite athletes, the odds ratio of ACE DD genotype being an endurance athlete was 3.26 (95% confidence interval 1.49–7.11), and of ACE II genotype was 0.41 (95% confidence interval 0.14–1.19). We conclude that in Israeli elite marathon runners the frequency of the ACE D allele and ACE DD genotype seems to be higher than in sprinters, suggesting a positive association between the D allele and the likelihood of being an elite endurance athlete in some ethnic groups.

The Effect of a Brief Sprint Interval Exercise on Growth Factors and Inflammatory Mediators

Meckel, Y, Eliakim, A, Seraev, M, Zaldivar, F, Cooper, DM, Sagiv, M, and Nemet, D. The effect of a brief sprint interval exercise on growth factors and inflammatory mediators. J Strength Cond Res 23(1): 225-230, 2009-Exercise training efficiency depends on the intensity, volume, duration, and frequency of training, as well as on the athletes ability to tolerate it. Recent efforts to quantify the effects of aerobic exercise training on hormonal response have suggested that exercise leads to simultaneous changes of antagonistic mediators. The effects of anaerobic exercise on these mediators are not known. Therefore, the aim of the present study was to evaluate the effects of a brief sprint interval session on the balance between anabolic (growth hormone [GH]→ insulin-like growth factor [IGF]-I axis) and catabolic hormones (cortisol), and circulating inflammatory cytokines such as interleukin (IL)-6. Twelve healthy elite junior handball players (17-20 years) participated in the study. Exercise consisted of a 4 × 250-m run on a treadmill, at a constant intensity of 80% of the personal maximal speed. Each run was separated by 3 minutes of rest. Blood samples were collected before, immediately after each 250-m run, and 1 hour after the last run. Exercise led to significant increases in GH (0.3 ± 0.2 to 5.1 ± 2.2 ng·ml−1, p < 0.05), IGF binding protein (IGFBP)-3 (4191 ± 2.48 to 4875 ± 301 ng·ml−1, p < 0.05), IL-6 (1.3 ± 0.2 to 2.1 ± 0.3 pg·ml−1, p < 0.002), testosterone, and testosterone/cortisol ratio, and to a significant decrease in IGFBP-1 levels. Levels of IL-6 remained elevated 1 hour after the end of exercise. Exercise had no significant effects on IGF-I and cortisol levels. Changes in the GH-IGF-I axis and testosterone/cortisol ratio after the brief sprint interval exercise suggested exercise-related anabolic adaptations. The increase in IL-6 may indicate its important role in muscle tissue repair after anaerobic exercise. Changes in the anabolic-catabolic hormonal balance and in inflammatory mediators can be used as an objective tool to gauge the training intensity of different types of anaerobic exercises and training periods.

Human, Environmental & Exercise: The ACE deletion allele is associated with Israeli elite endurance athletes

An Alu insertion (I)/deletion (D) polymorphism in the angiotensin I converting enzyme (ACE) gene has been associated with ACE activity. Opposing effects on elite athletic performance have been proposed for the I and D alleles; while the D allele favours improved endurance ability, the I allele promotes more power‐orientated events. We tested this hypothesis by determining the frequency of ACE ID alleles amongst 121 Israeli top‐level athletes classified by their sporting discipline (marathon runners or sprinters). Genotyping for ACE ID was performed using polymerase chain reaction on DNA from leucocytes. The ACE genotype and allele frequencies were compared with those of 247 healthy individuals. Allele and genotype frequencies differed significantly between the groups. The frequency of the D allele was 0.77 in the marathon runners, 0.66 in the control subjects (P= 0.01) and 0.57 in the sprinters (P= 0.002). The ACE DD genotype was more prevalent among the endurance athletes (0.62) than among the control subjects (0.43, P= 0.004) and the power athletes (0.34, P= 0.004). In the group of elite athletes, the odds ratio of ACE DD genotype being an endurance athlete was 3.26 (95% confidence interval 1.49–7.11), and of ACE II genotype was 0.41 (95% confidence interval 0.14–1.19). We conclude that in Israeli elite marathon runners the frequency of the ACE D allele and ACE DD genotype seems to be higher than in sprinters, suggesting a positive association between the D allele and the likelihood of being an elite endurance athlete in some ethnic groups.

Exercise Training Improves Diastolic Function in Heart Failure Patients

PURPOSE The studys purpose was to analyze the effects of exercise training on exercise tolerance and left ventricular systolic function and structure in heart failure patients with preserved, mild, and moderate to severe reduction of left ventricular ejection fraction (LVEF). METHODS Ninety-eight patients with moderate to severe (n = 34), mild (n = 33), and preserved (n = 31) LVEF were randomly assigned to exercise training plus usual care (n = 65) or usual care alone (n = 33) in a randomization ratio of 2:1. Left ventricular function, left ventricular dimensions, and exercise tolerance were assessed before and after each intervention. RESULTS Exercise tolerance and LVEF increased with exercise training in all patient groups, whereas they remained unchanged after usual care alone. Exercise training increased the mean ratio of early to late mitral inflow velocities (E/A ratio) and decreased deceleration time (DT) of early filling in patients with mild and preserved LVEF. In patients with moderate to severe systolic dysfunction and advanced diastolic dysfunction (DT < 160 ms), exercise training decreased E/A ratio and increased DT, both of which were unchanged after usual care alone. In the remaining patients (DT > 160 ms), exercise training also improved mitral inflow patterns. Exercise training decreased left ventricular dimensions in patients with mild and moderate to severe reduction of LVEF but not in patients with preserved LVEF. CONCLUSIONS These results indicate that exercise training can improve the course of heart failure independent of the degree of baseline left ventricular dysfunction.

Dilated Inferior Vena Cava: A Common Echocardiographic Finding in Highly Trained Elite Athletes☆☆☆

Typical structural features of the athletes heart as defined by echocardiography have been extensively described; however, information concerning extracardiac structures such as the inferior vena cava (IVC) is scarce. Fifty-eight top-level athletes and 30 healthy members of a matched control group underwent a complete Doppler echocardiographic study. IVC diameter was determined in the subxiphoid approach 10 to 20 mm away from its junction to the right atrium. Measures reflect the median values between maximal inspiratory and expiratory values. IVC respiratory collapsibility index was determined as well. IVC in athletes was 2.31 +/- 0.46 cm compared with 1.14 +/- 0.13 cm in the control group (P <.001). Swimmers had an IVC diameter of 2.66 +/- 0.48 cm compared with 2.17 +/- 0.41 cm in other athletes (P <.05). The IVC was normal (/=2.6 cm) in 24.1% of athletes. The collapsibility index was 58% +/- 6.4% in athletes compared with 70.2% +/- 4.9% in the control group (P <. 001). Correlation was found between IVC size and VO(2) max (r = 0.81, P <.001) and the right ventricle (r = 0.81, P <.001) and with collapsibility index (r = -0.57, P <.05). Multiple regression analysis showed the impact of VO(2) max, cardiac index, and right ventricular and left ventricular end-diastolic dimensions on IVC diameter. IVC dilatation probably represents adaptation of an extracardiac structure to chronic strenuous exercise in top-level, elite athletes.

Aldosterone Synthase Gene Polymorphism as a Determinant of Atrial Fibrillation in Patients With Heart Failure

We analyzed the possible association between aldosterone synthase (CYP11B2) T-344C polymorphism, which is associated with increased aldosterone activity, and the prevalence of atrial fibrillation (AF) in 196 consecutive patients who had symptomatic systolic heart failure (HF; left ventricular ejection fraction <40%) for > or =3 months before recruitment. Genomic DNA was extracted from peripheral blood leukocytes using a standard protocol. Subjects were genotyped for the CYP11B2 polymorphism using the polymerase chain reaction/restriction fragment length polymorphism approach. AF was present in 63 patients (33%) with HF. We found the -344 CC genotype to be a strong independent marker for AF. Almost 1/2 (45%) of patients with this genotype had AF compared with 1/4 (27%) with -344 TT and TC genotypes (p = 0.01). A multivariate stepwise logistic regression model that included age, gender, New York Heart Association class, CYP11B2 -344CC genotype, and echocardiographic measurements of left ventricular ejection fraction, left atrial dimension, left ventricular end-diastolic diameter, and mitral regurgitation severity showed that the CYP11B2 CC genotype (adjusted for age and left atrial size) was an independent predictor of AF (adjusted odds ratio 2.35, 95% confidence interval 1.57 to 3.51, p = 0.03). In conclusion, CYP11B2 T-344C promoter polymorphism predisposes to clinical AF in patients with HF.

Left ventricular responses during prolonged treadmill walking with heavy load carriage

This study examined with metabolic cart and echo-Doppler the influence of different load carriage during 4 h of treadmill walking on left ventricular systolic function, hemodynamics, and cardiovascular responses. Twenty-six aerobically well-trained male subjects (VO2max = 65.2 +/- 5 ml.kg-1.min-1) volunteered for this study. Subjects carried a load of 38 kg during one session and a load of 50 kg during the other session. Following the 4-h exercise in each session, significant (P < 0.05) differences were noted between the 38-kg and 50-kg workloads with regard to VO2: 14.4 +/- 2 and 19 +/- 5 ml.kg-1.min-1; heart rate: 104 +/- 14 and 125 +/- 17 beats.min-1; diastolic blood pressure: 69 +/- 4 and 79 +/- 4 mm Hg; and rate pressure product 140.4 +/- 15 and 173.8 +/- 20 index.10(-2), respectively. No significant differences were noted between the workloads in regard to systolic blood pressure, perceived exertion rating, and aortic valve Doppler indices. We concluded that during prolonged treadmill walking in well-trained young subjects, the additional load above 50% up to 66% of body weight did not change the steady state of left ventricular systolic function, hemodynamics, and cardiovascular responses throughout the course of the 240 min of effort.

Is there an interaction between PPARD T294C and PPARGC1A Gly482Ser polymorphisms and human endurance performance

Functional Gly482Ser (rs8192678) and T294C (rs2016520) polymorphisms in the peroxisome proliferator‐activated receptor γ coactivator‐1 (PPARGC1A) and peroxisome proliferator‐activated receptor δ (PPARD) genes, respectively, have been associated with mRNA and/or protein activity. The aim of this study was to determine their frequency distribution among 155 Israeli athletes (endurance athletes and sprinters) and 240 healthy control subjects. There were no differences between the endurance athletes, the sprinters and the control group across the PPARD T294C genotypes (P= 0.62). Similarly, no statistical differences were found between the subgroups of elite‐level endurance athletes (those who had represented Israel in a world track and field championship or in the Olympic Games) and national‐level endurance athletes (P= 0.3), or between elite‐level and national‐level sprinters (P= 0.9). However, a combined influence of these two polymorphisms on endurance performance was found. The PPARD CC +PPARGC1A Gly/Gly genotypes were more frequently found in the elite endurance athletes than in national‐level endurance athletes (P < 0.000). In the cohort of endurance athletes, the odds ratio of the ‘optimal genotype’ for endurance athletes (PPARD CC +PPARGC1A Gly/Gly +PPARGC1A Gly/Ser) being an elite‐level athlete was 8.32 (95% confidence interval 2.2–31.4). In conclusion, the present study suggests that PPARD T294C is not associated with endurance performance. However, a higher frequency of the PPARGC1A Gly/Gly +PPARD CC genotype is associated with elite‐level endurance athletes.

Left ventricular contractility and function at peak aerobic and anaerobic exercises.

PURPOSE The present study compared and evaluated left ventricular function and contractility at peak incremental aerobic type exercise and all-out explosive anaerobic effort in young healthy trained subjects. METHODS Twenty-two young healthy trained subjects (19 +/- 1 yr) were studied by two-dimensional direct M-mode echocardiography at peak aerobic and at peak all-out anaerobic exercises, performed on cycle ergometer. RESULTS All subjects completed the study without any electrocardiographic abnormalities. Significant (P < 0.05) differences between the aerobic and the anaerobic efforts were noted for peak cardiac output (24 +/- 2.0 and 15.0 +/- 1.1 L x min (-1), respectively), left ventricular pressure-volume ratio (5.8 +/- 0.6 and 4.7 +/- 0.5 respectively), end systolic volume (33 +/- 4 and 42 +/- 5 mL, respectively), ejection fraction (79 +/- 7 and 66 +/- 5%, respectively), and total peripheral resistance (TPR) (367 +/- 90 and 704 +/- 90 dynes x s(-1) x cm(- 5), respectively). CONCLUSIONS These data suggest that left ventricular at peak all out anaerobic effort differed markedly from those observed at peak aerobic exercise. These differences are presumably due to the different after-load responses between the two exercise modes. Therefore, it is suggested that anaerobic-type effort should be performed with great caution in normal young healthy subjects.

Paraoxonase activity following exercise-based cardiac rehabilitation program.

PURPOSE: The effect of gender on paraoxonase activity was determined in 37 ischemic heart disease patients who underwent a 12-week aerobic exercise training program. METHODS: Paraoxonase activity was measured by its arylesterase activity (spectrophotometrically, at 250°C, wavelength 270 nm). RESULTS: A 16.7% increase in paraoxonase activity was found following the 12-week exercise program. In addition, there was a significant gender effect with higher mean paraoxonase levels among women during both preexercise (20.8%) and postexercise (24.2%) testing. CONCLUSIONS: Aerobic exercise training was found to be an effective means in inducing plasma levels elevation of the antioxidative, antiatherogenic paraoxonase in patients with coronary artery disease, and particularly in female patients.