The ACE gene and muscle performance

Multi-species comparative analysis of the equine ACE gene identifies a highly conserved potential transcription factor binding site in intron 16

Angiotensin converting enzyme (ACE) is essential for control of blood pressure. The human ACE gene contains an intronic Alu indel (I/D) polymorphism that has been associated with variation in serum enzyme levels, although the functional mechanism has not been identified. The polymorphism has also been associated with cardiovascular disease, type II diabetes, renal disease and elite athleticism. We have characterized the ACE gene in horses of breeds selected for differing physical abilities. The equine gene has a similar structure to that of all known mammalian ACE genes. Nine common single nucleotide polymorphisms (SNPs) discovered in pooled DNA were found to be inherited in nine haplotypes. Three of these SNPs were located in intron 16, homologous to that containing the Alu polymorphism in the human. A highly conserved 18 bp sequence, also within that intron, was identified as being a potential binding site for the transcription factors Oct-1, HFH-1 and HNF-3β, and lies within a larger area of higher than normal homology. This putative regulatory element may contribute to regulation of the documented inter-individual variation in human circulating enzyme levels, for which a functional mechanism is yet to be defined. Two equine SNPs occurred within the conserved area in intron 16, although neither of them disrupted the putative binding site. We propose a possible regulatory mechanism of the ACE gene in mammalian species which was previously unknown. This advance will allow further analysis leading to a better understanding of the mechanisms underpinning the associations seen between the human Alu polymorphism and enzyme levels, cardiovascular disease states and elite athleticism.

Angiotensin-converting enzyme gene polymorphism in north Indian population with obstructive sleep apnea

BACKGROUND

A deletion of 287-bp Alu repeat of angiotensin-converting enzyme (ACE) insertion/deletion (I/D) gene is associated with hypertension.

PURPOSE

The aim of this study is to determine the frequency of ACE (I/D) polymorphism in patients with obstructive sleep apnea (OSA).

METHODS

Genotyping of ACE (I/D) gene polymorphism and estimation of serum angiotensin-converting enzyme (SACE) activity were done in 813 subjects who underwent polysomnography. Of these, 395 were apneics and 418 were non-apneics.

RESULTS

The frequencies of II genotype (OR = 1.8, 95 % CI 1.26-2.60, p = 0.001) and I allele (OR = 1.4, 95 % CI 1.13-1.69, p = 0.001) of ACE gene were found to be significantly increased in patients with OSA as compared to patients without OSA. Frequency of II genotype was significantly decreased (OR = 0.46, 95 % CI 0.28-0.77, p = 0.003) in OSA patients with hypertension. In contrast, the frequencies of ID (OR = 1.80, 95 % CI 1.08-2.99, p = 0.024) and DD genotypes (OR = 2.15, 95 % CI 1.30-3.57, p = 0.003) were significantly increased in this group. The activity of SACE was significantly decreased in the apneic group as compared to the non-apneic group (OR = 0.99, 95 % CI 0.98-1.00, p = 0.04).

CONCLUSIONS

The findings suggest that II genotype confers susceptibility towards development of OSA whereas DD genotype confers susceptibility towards hypertension irrespective of OSA.

The association of sport performance with ACE and ACTN3 genetic polymorphisms: a systematic review and meta-analysis

Background

Genetic polymorphism is suggested to be associated with human physical performance. The angiotensin I-converting enzyme insertion/deletion (ACE I/D) polymorphism and the α-actinin-3 gene (ACTN3) R577X polymorphism have been most widely studied for such association analysis. However, the findings are frequently heterogeneous. We aim to summarize the associations of ACE I/D and ACTN3 R577X with sport performance by means of meta-analysis.

Methods

We systematically reviewed and quantitatively summarized published studies, until October 31, 2012, on relationship between ACE/ACTN3 genetic polymorphisms and sports performance, respectively.

Results

A total of 366 articles on ACE and 88 articles on ACTN3 were achieved by literature search. A significant association was found for ACE II genotype compared to D allele carriage (DD+ID) with increased possibility of physical performance (OR, 1.23; 95% CI, 1.05–1.45). With respect to sport discipline, the II genotype was found to be associated with performance in endurance athletes (OR, 1.35; 95% CI, 1.17–1.55). On the other hand, no significant association was observed for ACTN3 RR genotype as compared to X allele carriage (XX+RX) (OR, 1.03; 95% CI, 0.92–1.15). However, when restricted the analyses to power events, a significant association was observed (OR, 1.21; 95% CI, 1.03–1.42).

Conclusion

Our results provide more solid evidence for the associations between ACE II genotype and endurance events and between ACTN3 R allele and power events. The findings suggest that the genetic profiles might influence human physical performance.

Genomics of elite sporting performance: what little we know and necessary advances

Numerous reports of genetic associations with performance- and injury-related phenotypes have been published over the past three decades; these studies have employed primarily the candidate gene approach to identify genes that associate with elite performance or with variation in performance-and/or injury-related traits. Although generally with small effect sizes and heavily prone to type I statistic error, the number of candidate genetic variants that can potentially explain elite athletic status, injury predisposition, or indeed response to training will be much higher than that examined by numerous biotechnology companies. Priority should therefore be given to applying whole genome technology to sufficiently large study cohorts of world-class athletes with adequately measured phenotypes where it is possible to increase statistical power. Some of the elite athlete cohorts described in the literature might suffice, and collectively, these cohorts could be used for replication purposes. Genome-wide association studies are ongoing in some of these cohorts (i.e., Genathlete, Russian, Spanish, Japanese, United States, and Jamaican cohorts), and preliminary findings include the identification of one single nucleotide polymorphism (SNP; among more than a million SNPs analyzed) that associates with sprint performance in Japanese, American (i.e., African American), and Jamaican cohorts with a combined effect size of ~2.6 (P-value <5×10(-7)) and good concordance with endurance performance between select cohorts. Further replications of these signals in independent cohorts will be required, and any replicated SNPs will be taken forward for fine-mapping/targeted resequencing and functional studies to uncover the underlying biological mechanisms. Only after this lengthy and costly process will the true potential of genetic testing in sport be determined.

Renin-angiotensin system blockade: a novel therapeutic approach in chronic obstructive pulmonary disease

ACE (angiotensin-converting enzyme) inhibitors and ARBs (angiotensin II receptor blockers) are already widely used for the treatment and prevention of cardiovascular disease and their potential role in other disease states has become increasingly recognized. COPD (chronic obstructive pulmonary disease) is characterized by pathological inflammatory processes involving the lung parenchyma, airways and vascular bed. The aim of the present review is to outline the role of the RAS (renin-angiotensin system) in the pathogenesis of COPD, including reference to results from fibrotic lung conditions and pulmonary hypertension. The review will, in particular, address the emerging evidence that ACE inhibition could have a beneficial effect on skeletal muscle function and cardiovascular co-morbidity in COPD patients. The evidence to support the effect of RAS blockade as a novel therapeutic approach in COPD will be discussed.

Can genes influencing muscle function affect the therapeutic response to enzyme replacement therapy (ERT) in late-onset type II glycogenosis?

The purpose of this study is to analyze the role of genes known to influence muscle performances on the outcome after enzyme replacement treatment (ERT) in type II Glycogenosis (GSDII). We analyzed 16 patients receiving ERT for ≥two years. We assessed the changes in muscle strength by hand-held dynamometry, muscle mass by quantitative MRI, and resistance to exercise by the 6-minute walking test. Exercise gene assessment included angiotensin converting enzyme insertion/deletion polymorphism (ACE), alpha-actinin3 R577X polymorphism (ACTN3), and peroxisome proliferator activated receptor alpha G/C polymorphism (PPARα). Independent of disease severity, one third of patients had a poor response to ERT, which was found to be associated with ACE DD genotype. The ACTN3 null polymorphism appeared to exert a positive effect on treatment efficacy, while PPARα did not seem to exert any influence at all. We conclude that poor treatment outcome in ACE DD genotypes is in line with previous observation of a worse disease course in this subpopulation, and suggests the need for a more careful follow-up and individualized treatment approaches for these patients. Exercise genes may provide a new opportunity for studying the outcome after treatment and the muscle regeneration abilities in other models of genetic myopathies.

Skeletal muscle mitochondrial density, gene expression, and enzyme activities in human heart failure: minimal effects of the disease and resistance training

Impaired skeletal muscle energetics could adversely affect physical and metabolic function in patients with heart failure (HF). The effect of HF on aspects of mitochondrial structure and function, independent of muscle disuse and other disease-related confounding factors, however, is unclear. Moreover, no study has evaluated whether resistance exercise training, a modality that increases functional capacity, might derive its benefits through modulation of mitochondrial structure and function. Thirteen HF patients and 14 age- and physical activity-matched controls were evaluated for skeletal muscle mitochondrial size/content, gene expression, and enzyme activity before and after an 18-wk resistance exercise-training program. At baseline, HF patients and controls had similar mitochondrial fractional areas, although HF patients had larger average mitochondrion size (P < 0.05) and a trend toward a reduced number of mitochondria (P ≤ 0.10). No differences in the expression of transcriptional regulators or cytochrome oxidase subunits or the activity of mitochondrial and cytosolic enzymes were noted. Relationships among transcriptional regulators suggested that networks controlling mitochondrial content and gene expression are intact. Resistance training increased (P < 0.01) mitochondrial transcription factor A expression in patients and controls, and this increase was related to improvements in muscle strength (P = 0.05). Training did not, however, alter mitochondrial size/content, enzyme activities, or expression of other transcriptional regulators. In conclusion, our results suggest that the HF syndrome has minimal effects on skeletal muscle mitochondrial biology when the confounding effects of muscle disuse and other disease-related factors are removed. Moreover, the beneficial effects of resistance training on physical function in HF patients and controls are likely not related to alterations in mitochondrial biology.

Variation in the uncoupling protein 2 and 3 genes and human performance

Uncoupling proteins 2 and 3 (UCP2 and UCP3) may negatively regulate mitochondrial ATP synthesis and, through this, influence human physical performance. However, human data relating to both these issues remain sparse. Examining the association of common variants in the UCP3/2 locus with performance phenotypes offers one means of investigation. The efficiency of skeletal muscle contraction, delta efficiency (DE), was assessed by cycle ergometry in 85 young, healthy, sedentary adults both before and after a period of endurance training. Of these, 58 were successfully genotyped for the UCP3-55C>T (rs1800849) and 61 for the UCP2-866G>A (rs659366) variant. At baseline, UCP genotype was unrelated to any physical characteristic, including DE. However, the UCP2-866G>A variant was independently and strongly associated with the DE response to physical training, with UCP2-866A allele carriers exhibiting a greater increase in DE with training (absolute change in DE of -0.2 ± 3.6% vs. 1.7 ± 2.8% vs. 2.3 ± 3.7% for GG vs. GA vs. AA, respectively; P = 0.02 for A allele carriers vs. GG homozygotes). In multivariate analysis, there was a significant interaction between UCP2-866G>A and UCP3-55C>T genotypes in determining changes in DE (adjusted R(2) = 0.137; P value for interaction = 0.003), which was independent of the effect of either single polymorphism or baseline characteristics. In conclusion, common genetic variation at the UCP3/2 gene locus is associated with training-related improvements in DE, an index of skeletal muscle performance. Such effects may be mediated through differences in the coupling of mitochondrial energy transduction in human skeletal muscle, but further mechanistic studies are required to delineate this potential role.

The higher exercise intensity and the presence of allele I of ACE gene elicit a higher post-exercise blood pressure reduction and nitric oxide release in elderly women: an experimental study

BACKGROUND

The absence of the I allele of the angiotensin converting enzyme (ACE) gene has been associated with higher levels of circulating ACE, lower nitric oxide (NO) release and hypertension. The purposes of this study were to analyze the post-exercise salivary nitrite (NO2-) and blood pressure (BP) responses to different exercise intensities in elderly women divided according to their ACE genotype.

METHODS

Participants (n = 30; II/ID = 20 and DD = 10) underwent three experimental sessions: incremental test - IT (15 watts workload increase/3 min) until exhaustion; 20 min exercise 90% anaerobic threshold (90% AT); and 20 min control session without exercise. Volunteers had their BP and NO2- measured before and after experimental sessions.

RESULTS

Despite both intensities showed protective effect on preventing the increase of BP during post-exercise recovery compared to control, post-exercise hypotension and increased NO2- release was observed only for carriers of the I allele (p < 0.05).

CONCLUSION

Genotypes of the ACE gene may exert a role in post-exercise NO release and BP response.

The ACE gene and human performance: 12 years on

Some 12 years ago, a polymorphism of the angiotensin I-converting enzyme (ACE) gene became the first genetic element shown to impact substantially on human physical performance. The renin-angiotensin system (RAS) exists not just as an endocrine regulator, but also within local tissue and cells, where it serves a variety of functions. Functional genetic polymorphic variants have been identified for most components of RAS, of which the best known and studied is a polymorphism of the ACE gene. The ACE insertion/deletion (I/D) polymorphism has been associated with improvements in performance and exercise duration in a variety of populations. The I allele has been consistently demonstrated to be associated with endurance-orientated events, notably, in triathlons. Meanwhile, the D allele is associated with strength- and power-orientated performance, and has been found in significant excess among elite swimmers. Exceptions to these associations do exist, and are discussed. In theory, associations with ACE genotype may be due to functional variants in nearby loci, and/or related genetic polymorphism such as the angiotensin receptor, growth hormone and bradykinin genes. Studies of growth hormone gene variants have not shown significant associations with performance in studies involving both triathletes and military recruits. The angiotensin type-1 receptor has two functional polymorphisms that have not been shown to be associated with performance, although studies of hypoxic ascent have yielded conflicting results. ACE genotype influences bradykinin levels, and a common gene variant in the bradykinin 2 receptor exists. The high kinin activity haplotye has been associated with increased endurance performance at an Olympic level, and similar results of metabolic efficiency have been demonstrated in triathletes. Whilst the ACE genotype is associated with overall performance ability, at a single organ level, the ACE genotype and related polymorphism have significant associations. In cardiac muscle, ACE genotype has associations with left ventricular mass changes in response to stimulus, in both the health and diseased states. The D allele is associated with an exaggerated response to training, and the I allele with the lowest cardiac growth response. In light of the I-allele association with endurance performance, it seems likely that other regulatory mechanisms exist. Similarly in skeletal muscle, the D allele is associated with greater strength gains in response to training, in both healthy individuals and chronic disease states. As in overall performance, those genetic polymorphisms related to the ACE genotype, such as the bradykinin 2 gene, also influence skeletal muscle strength. Finally, the ACE genotype may influence metabolic efficiency, and elite mountaineers have demonstrated an excess of I alleles and I/I genotype frequency in comparison to controls. Interestingly, this was not seen in amateur climbers. Corroboratory evidence exists among high-altitude settlements in both South America and India, where the I allele exists in greater frequency in those who migrated from the lowlands. Unfortunately, if the ACE genotype does influence metabolic efficiency, associations with peak maximal oxygen consumption have yet to be rigorously demonstrated. The ACE genotype is an important but single factor in the determinant of sporting phenotype. Much of the mechanisms underlying this remain unexplored despite 12 years of research.

No association between ACE gene variation and endurance athlete status in Ethiopians

PURPOSE

The most widely studied candidate gene for endurance performance is the angiotensin-converting enzyme (ACE) gene. The best endurance runners in the world hail from Kenya and Ethiopia, so the lack of association between the ACE gene and elite endurance athlete status we previously reported in Kenyans requires replication in Ethiopians.

METHODS

DNA was extracted from buccal swabs collected from subjects filling four groups: elite endurance runners from the Ethiopian national athletics team specializing in 5 km to marathon distances (n = 76), controls demographically matched to the elite endurance athletes (n = 410), controls representing the general Ethiopian population (n = 317), and sprint and power event athletes from the Ethiopian national athletics team (n = 38). ACE I/D and A22982G (rs4363) genotype frequencies were determined for each of these groups, and differences between groups were assessed using χ(2) tests.

RESULTS

There were no significant deviations from Hardy-Weinberg equilibrium in endurance athletes or either control group. Endurance athletes did not differ significantly in ACE I/D genotype frequency when compared with the endurance athlete-matched control group (P = 0.16), general controls (P = 0.076), or sprint and power athletes (P = 0.39) (endurance athletes: 15.8% II, endurance athlete-matched controls: 8.8% II, general controls: 7.6% II, sprint and power athletes: 10.5% II). Similarly, no significant differences were found in ACE A22982G genotype between groups (endurance athletes: 13.2% AA, endurance athlete-matched controls: 12.2% AA, general controls: 12.0% AA, sprint and power athletes: 13.2%; endurance athletes vs endurance athlete-matched controls: P = 0.97, endurance athletes vs general controls: P = 0.95, endurance athletes vs sprint and power athletes: P = 0.52).

CONCLUSIONS

As previously shown in elite Kenyan athletes, ACE I/D and A22982G polymorphisms are not associated with elite endurance athlete status in Ethiopians.

Circulating angiotensin converting enzyme in endurance horses: effect of exercise on blood levels and its value in predicting performance

REASONS FOR PERFORMING STUDY

Investigate angiotensin converting enzyme (ACE) activity in equine plasma as a predictor of performance in endurance competitions and the effect of endurance exercise on ACE activity.

HYPOTHESIS

Precompetition values of ACE activity in equine blood are correlated with performance results and with heart rates pre- and post competition used as indicators of fitness. Endurance exercise increases ACE activity.

METHODS

Nineteen horses participating in an 80 km endurance competition had venous blood samples collected before and after the ride. ACE activity and total protein were measured in the blood samples and heart rates and finishing positions were recorded. Statistical analysis included paired t tests and Spearman's rank correlation coefficient.

RESULTS

Of the 19 horses enlisted, only 16 horses completed the ride. Of these 16, another 2 were disqualified at the last veterinary check. When the 16 horses were considered, precompetition heart rate, but not ACE, was correlated with finishing position. When only the 14 horses that were classified were considered, the association disappeared. ACE activity was similar before and after competition.

CONCLUSIONS

Precompetition ACE activity in endurance horses competing in an 80 km event was not associated with either finishing position or heart rates before or after competition, indicating that the enzyme is not a good predictor of performance in this form of equestrian competition. Endurance competition did not significantly alter ACE activity in this group of horses.

Current and future pharmacologic treatment of sarcopenia

Sarcopenia is a complex multifactorial condition that can by treated with multimodal approaches. No pharmacologic agent to prevent or treat sarcopenia has been as efficacious as exercise (mainly resistance training) in combination with nutritional intervention (adequate protein and energy intake). However, performing resistance training sessions and following nutritional advice can be challenging, especially for frail, sarcopenic, elderly patients, and results remain only partial. Therefore, new pharmacologic agents may substantially reduce the functional decline in older people. This article reviews the new pharmacologic agents currently being assessed for treating sarcopenia.

Angiotensin-converting enzyme gene polymorphism and respiratory muscle function in infants

OBJECTIVE

Angiotensin-converting enzyme (ACE) gene contains a polymorphism consisting of either the presence (I) or absence (D) of a 287-bp fragment. Recent studies have suggested that the I-allele may be associated with superior exercise endurance; respiratory muscle function may be similarly influenced. The pressure-time index of inspiratory muscles (PTImus) is a measure of the load-capacity ratio of the inspiratory muscles. The objective of this study was to determine whether infants homozygous for the I-allele have lower PTImus compared to infants homozygous for the D-allele or heterozygous I/D.

PATIENTS AND METHODS

One hundred thirty-two infants were studied. ACE genotyping was performed by polymerase chain reaction amplification, using DNA from peripheral blood. PTImus was calculated as (Pi(mean)/Pi(max)) × (T(i)/T(tot)), where Pi(mean) was the mean inspiratory pressure estimated from airway pressure, generated 100 ms after an occlusion (P(0.1)), Pi(max) was the maximum inspiratory pressure and T(i)/T(tot) was the ratio of the inspiratory time to the total respiratory cycle time. Pi(max) was the largest pressure generated during brief airway occlusions performed at the end of a spontaneous crying effort.

RESULTS

Infants with I/I genotype had significantly lower PTImus than infants with either D/D or I/D genotypes (P = 0.000007). ACE genotype was significantly related (P = 0.005) to PTImus measurements, independent of other factors that may affect respiratory muscle function.

CONCLUSION

These results suggest that an association of ACE genotypes with PTImus measurements may exist in infants.

Optimal management of sarcopenia

Sarcopenia is the progressive generalized loss of skeletal muscle mass, strength, and function which occurs as a consequence of aging. With a growing older population, there has been great interest in developing approaches to counteract the effects of sarcopenia, and thereby reduce the age-related decline and disability. This paper reviews (1) the mechanisms of sarcopenia, (2) the diagnosis of sarcopenia, and (3) the potential interventions for sarcopenia. Multiple factors appear to be involved in the development of sarcopenia including the loss of muscle mass and muscle fibers, increased inflammation, altered hormonal levels, poor nutritional status, and altered renin-angiotensin system. The lack of diagnostic criteria to identify patients with sarcopenia hinders potential management options. To date, pharmacological interventions have shown limited efficacy in counteracting the effects of sarcopenia. Recent evidence has shown benefits with angiotensin-converting enzyme inhibitors; however, further randomized controlled trials are required. Resistance training remains the most effective intervention for sarcopenia; however, older people maybe unable or unwilling to embark on strenuous exercise training programs.

Does the ACE I/D polymorphism, alone or in combination with the ACTN3 R577X polymorphism, influence muscle power phenotypes in young, non-athletic adults?

We investigated the association of the angiotensin converting enzyme gene (ACE) insertion/deletion (I/D) polymorphism, alone or in combination with the α-actinin-3 gene (ACTN3) R577X polymorphism, with jumping (vertical squat and counter-movement jump tests) and sprint ability (30 m dash) in non-athletic, healthy young adults [N = 281 (214 male), mean (SD) age 21 (2) years]. We did not observe any effect of the ACE I/D polymorphism on study phenotypes. We repeated the analyses separately in men and women and the results did not materially change. Likewise, the mean estimates of the study phenotypes were similar in subjects with the genotype combinations ACE II + ID and ACTN3 XX or ACE DD and ACTN3 RR + RX. We found no association between the ACE DD and ACTN3 RR + RX genotype combination and performance (≥90th of the sex-specific percentile). In summary, though the ACE I/D polymorphism is a strong candidate to modulate some exercise-related phenotypes or athletic performance status, this polymorphism, alone or in combination with the ACTN3 R577X polymorphism, does not seem to exert a major influence in the muscle 'explosive' power of young healthy adults, as assessed during multi-joint exercise tests.

Angiotensin-converting enzyme I/D polymorphism in chronic obstructive pulmonary disease

Study objective

The etiology of chronic obstructive lung disease (COPD) is unclear. It is supposed to be the product of an exogenous antigenic stimulus, such as tobacco smoke, and an endogenous genetic susceptibility. The angiotensin-converting enzyme (ACE) gene contains a polymorphism based on the presence (insertion [I]) or absence (deletion [D]) of a 287-bp nonsense domain, resulting in three different genotypes (II, ID and DD). The aim of the study was to find out whether the ACE gene polymorphism can determine the course of COPD.

Patients and design

We genotyped 152 Caucasian patients with COPD and 158 healthy controls for the ACE (I/D) polymorphism. We divided the COPD group into one group of 64 patients with a stable course of disease, defined as less than three hospitalizations over the last three years due to COPD, and another group of 88 patients with an instable course with more than three hospitalizations.

Results

The I-allele was significantly associated with an increased risk for COPD in a dominant model (OR 1.67 (95% CI 1.00 to 2.78), p = 0.048), but not in a recessive or co-dominant model. Moreover, the I-allele of ACE (I/D) was significantly increased in patients with a stable course of COPD (p = 0.012) compared with controls. In a dominant model (II/ID v DD) we found an even stronger association between the I-allele and a stable course of COPD (OR 3.24 (95% CI 1.44 to 7.31), p = 0.003).

Conclusion

These data suggest that the presence of an ACE I-allele determines a stable course of COPD.

The two-hour marathon: who and when?

Whoever breaks 2 h will likely have outstanding running economy and small body size along with exposure to high altitude and significant physical activity early in life. However, neither of these factors nor any specific suite of genotypes appear to be obligatory for a time this fast. Current trends suggest that an East African will be the first to break 2 h. However periods of regional dominance in distance running are not unique to the East Africans: athletes from Finland, Eastern Europe, Australia, and New Zealand have all had extended periods of success at a range of distances. From a physiological perspective, more information is clearly needed on the relationship between VO(2max) and running economy and the influence of running economy and body size on thermoregulation and fuel use.

C-reactive protein gene variant and the human left ventricular growth response to exercise: data from The LARGE Heart Study

OBJECTIVE

Increased levels of C-reactive protein (CRP) are associated with left ventricular (LV) hypertrophy. This association may be causal (either directly or indirectly) or simply a confounder resulting from the recognized relationship between CRP and vascular disease. We attempted to clarify this issue, by assessing the association of a variant of the CRP gene with exercise-induced left ventricular hypertrophy in young healthy males: homozygosity for the T (rather than C) allele of the CRP +1444C>T gene variant is associated with serum CRP levels which are 0.68 mg/L higher than carriers of the C allele.

METHODS AND RESULTS

LV mass was measured using cardiovascular magnetic resonance in 301 army recruits before and after an identical 12-week physical training program. Subjects were genotyped for the CRP +1444C>T gene variant. LV mass was 164.25 +/-24.52 g at entry and increased with training (+3.77 +/- 10.77 g). This increase was greatest among those homozygous for the rare T allele (+8.17 6 12.09 vs. +3.37 6 10.58 for TT genotype vs. C-allele carriers respectively, P = 0.033).

CONCLUSIONS

CRP genotype is associated with a greater LV growth to exercise, supporting a causal association between CRP and LV growth. Whether such an association might be directly mediated or results from alterations in phenotypes which themselves drive LV growth (for instance, altered arterial compliance) is not clear.

Treatment of obese adolescents: the influence of periodization models and ACE genotype

The aims of the present study were to compare the effects of two periodization models on metabolic syndrome risk factors in obese adolescents and verify whether the angiotensin-converting enzyme (ACE) genotype is important in establishing these effects. A total of 32 postpuberty obese adolescents were submitted to aerobic training (AT) and resistance training (RT) for 14 weeks. The subjects were divided into linear periodization (LP, n = 16) or daily undulating periodization (DUP, n = 16). Body composition, visceral and subcutaneous fat, glycemia, insulinemia, homeostasis model assessment of insulin resistance (HOMA-IR), lipid profiles, blood pressure, maximal oxygen consumption (VO(2max)), resting metabolic rate (RMR), muscular endurance were analyzed at baseline and after intervention. Both groups demonstrated a significant reduction in body mass, BMI, body fat, visceral and subcutaneous fat, total and low-density lipoprotein cholesterol, blood pressure and an increase in fat-free mass, VO(2max), and muscular endurance. However, only DUP promoted a reduction in insulin concentrations and HOMA-IR. It is important to emphasize that there was no statics difference between LP and DUP groups; however, it appears that there may be bigger changes in the DUP than LP group in some of the metabolic syndrome risk factors in obese adolescents with regard to the effect size (ES). Both periodization models presented a large effect on muscular endurance. Despite the limitation of sample size, our results suggested that the ACE genotype may influence the functional and metabolic characteristics of obese adolescents and may be considered in the future strategies for massive obesity control.

Elite Athletes: Are the Genes the Champions?

Recent research has analyzed the genetic factors that influence world-class athletic status. Much of what we know comes from association studies, with the ACE I/D and ACTN3 R577X polymorphisms having been extensively studied. The association between the ACTN3 R577X variation and elite athlete status in power sports is strongly documented, yet whether the current body of knowledge on other variants can be extrapolated to athletic champion status remains to be determined. Athletic champion status is a complex polygenic trait in which numerous candidate genes, complex gene–gene interactions, and environment–gene interactions are involved. Besides the need for more studies and new approaches taking into account the complexity of the problem, we believe that factors beyond genetic endowment are likely to have a stronger influence in the attainment of athletic champion status.

A role for succinate dehydrogenase genes in low chemoresponsiveness to hypoxia?

The detection of hypoxia by the carotid bodies elicits a ventilatory response of utmost importance for tolerance to high altitude. Germline mutations in three genes encoding subunit B, C and D of succinate dehydrogenase (SDHB, SDHC and SDHD) have been associated with paragangliomas of the carotid body. We hypothesized that SDH dysfunction within the carotid body could result in low chemoresponsiveness and intolerance to high altitude. The frequency of polymorphisms of SDHs, hypoxia-inducible factor type 1 (HIF1alpha) and angiotensin converting enzyme (ACE) genes was compared between 40 subjects with intolerance to high altitude and a low hypoxic ventilatory response at exercise (HVRe < or = 0.5 ml min(-1) kg(-1); HVR- group) and 41 subjects without intolerance to high altitude and a high HVRe (> or = 0.80 ml min(-1) kg(-1); HVR+). We found no significant association between low or high HVRe and (1) the allele frequencies for nine single nucleotide polymorphisms (SNPs) in the SDHD and SDHB genes, (2) the ACE insertion/deletion polymorphism and (3) four SNPs in the HIF1alpha gene. However, a marginal significant association was found between the synonymous polymorphism c.18A>C of the SDHB gene and chemoresponsiveness: 8/40 (20%) in the HVR- group and 3/41 (7%) in the HVR+ group (p = 0.12). A principal component analysis showed that no subject carrying the 18C allele had both high ventilatory and cardiac response to hypoxia. In conclusion, no clear association was found between gene variants involved in oxygen sensing and chemoresponsiveness, although some mutations in the SDHB and SDHD genes deserve further investigations in a larger population.

Is there a gender difference between ACE gene and race distance?

We aimed to examine the association between the angiotensin I-converting enzyme (ACE) gene (insertion (I) and deletion (D)) polymorphism in Japanese university track athletes and race distance, as well as to evaluate the gender effects on this association. The ACE I/D allele frequency was determined in 277 athletes (176 men, 101 women; aged 19.7 +/- 1.2 years), who were then grouped on the basis of their major competitive race distances (short distance (SD), < or = 200 m; middle distance (MD), 400-800 m, and long distance (LD), > or =1500 m). The ACE I allele frequency increased with the distance (44.4%, 48.4%, and 66.2% for the SD (n = 107), MD (n = 62), and LD (n = 108) groups, respectively; p < 0.001, chi(2) test). On multinomial logistic regression analysis, significant associations between ACE genotype and race distance were observed only in male athletes (ID vs. SD, p = 0.004; ID vs. LD, p = 0.030; II vs. LD, p = 0.001). There was no significant association between ACE genotype and race distance in female athletes. We conclude that the ACE I allele is overrepresented in endurance athletes, and that its frequency varies depending on gender.

The C allele of the AGT Met235Thr polymorphism is associated with power sports performance

Whether the Met235Thr (rs699) variation in the angiotensinogen (AGT) gene, encoding a threonine instead of a methionine in codon 235 of the mature protein, is associated with athletic performance remains to be elucidated. We compared the genotype and allele frequencies for the AGT Met235Thr variation (rs699) in 119 nonathletic controls, 100 world-class endurance athletes (professional cyclists, Olympic-class runners), and 63 power athletes (top-level jumpers, throwers, sprinters). Participants were all males and from the same descent (Caucasian) for ≥3 generations. The proportion of the CC genotype was significantly higher in the power group (34.9%) than in either the control (16%) or the endurance group (16%) (p = 0.008 and p = 0.005, respectively). The odds ratio (95% CI) of being a power athlete if the subject has a CC genotype was 1.681 (1.176–2.401), compared with the control group. In summary, the C allele of the AGT Met235Thr polymorphism might favour power sports performance. Although more research is needed, this could be attributed to the higher activity of angiotensin II, a skeletal muscle growth factor.

Validated treatments and therapeutics prospectives regarding pharmacological products for sarcopenia

Loss of physical function in older adults may be, at least in part, explained by sarcopenia, a phenomenon characterized by a reduction in number and size of muscle fibres and by increase in interstitial fat and connective tissue. Lifestyle intervention (i.e. physical activity and nutrition) have shown to impact on sarcopenia. However, several drugs were suggested, with various levels of scientific evidence, to have an impact on muscle outcomes. In this study we reviewed the effect of six classes of drugs on sarcopenia and muscular outcomes in older adults. We decided to focus our review on two commonly drugs which have recently showed promising effects on muscular outcomes in older adults (ACE inhibitors and statins) and on four drugs whose effect on skeletal muscle was already largely studied (creatine, Growth Hormone, testosterone, estrogens and tibolone).

Decreased muscle ACE activity enhances functional response to endurance training in rats, without change in muscle oxidative capacity or contractile phenotype

In the present study, we tested the hypothesis that chronic ANG I-converting enzyme (ACE) inhibition could improve the training-induced improvement in endurance exercise performance and that this could be related to enhanced skeletal muscle metabolic efficiency. Female Wistar rats were assigned to four groups comprising animals either maintained sedentary or endurance trained (Sed and Tr, respectively), and treated or not for 10 wk with an ACE inhibitor, perindopril (2 mg·kg−1·day−1) (Per and Ct, respectively) ( n = 8 each). Trained rats underwent an 8-wk treadmill training protocol that consisted of 2 h/day running at 30 m/min on a 8% decline. Before the start of and 1 wk before the end of experimental conditioning, the running time to exhaustion of rats was measured on a treadmill. The training program led to an increase in endurance time, higher in Tr-Per than in Tr-Ct group (125% in Tr-Ct vs. 183% in Tr-Per groups, P < 0.05). Oxidative capacity, measured in saponin-permeabilized fibers of slow soleus and fast plantaris muscles, increased with training, but less in Tr-Per than in Tr-Ct rats. The training-induced increase in citrate synthase activity also was less in soleus from Tr-Per than Tr-Ct rats. The training-induced increase in the percentage of the type IIa isoform of myosin heavy chain (MHC) (45%, P < 0.05) and type IIx MHC (25%, P < 0.05) associated with decreased type IIb MHC (34%, P < 0.05) was minimized by perindopril administration. These findings demonstrate that the enhancement in physical performance observed in perindopril-treated animals cannot be explained by changes in mitochondrial respiration and/or MHC distribution within muscles involved in running exercise.

Association between ACE D allele and elite short distance swimming

The influence of ACE gene on athletic performance has been widely explored, and most of the published data refers to an I/D polymorphism leading to the presence (I allele) or absence (D allele) of a 287-bp sequence in intron 16, determining ACE activity in serum and tissues. A higher I allele frequency has been reported among elite endurance athletes, while the D allele was more frequent among those engaged in more power-orientated sports. However, on competitive swimming, the reproducibility of such associations is controversial. We thus compared the ACE genotype of elite swimmers with that of non-elite swimming cohort and of healthy control subjects. We thus sought an association of the ACE genotype of elite swimmers with their competitive distance. 39 Portuguese Olympic swimming candidates were classified as: short (<200 m) and middle (400-1,500 m) distance swimmers, respectively. A group of 32 non-elite swimmers were studied and classified as well, and a control group (n = 100) was selected from the Portuguese population. Chelex 100 was used for DNA extraction and genotype was determined by PCR-RFLP methods. We found that ACE genotype distribution and allelic frequency differs significantly by event distance only among elite swimmers (P < or = 0.05). Moreover, the allelic frequency of the elite short distance swimmers differed significantly from that of the controls (P = 0.021). No associations were found between middle distance swimmers and controls. Our results seem to support an association between the D allele and elite short distance swimming.

The human gene map for performance and health-related fitness phenotypes: the 2006-2007 update

This update of the human gene map for physical performance and health-related fitness phenotypes covers the research advances reported in 2006 and 2007. The genes and markers with evidence of association or linkage with a performance or a fitness phenotype in sedentary or active people, in responses to acute exercise, or for training-induced adaptations are positioned on the map of all autosomes and sex chromosomes. Negative studies are reviewed, but a gene or a locus must be supported by at least one positive study before being inserted on the map. A brief discussion on the nature of the evidence and on what to look for in assessing human genetic studies of relevance to fitness and performance is offered in the introduction, followed by a review of all studies published in 2006 and 2007. The findings from these new studies are added to the appropriate tables that are designed to serve as the cumulative summary of all publications with positive genetic associations available to date for a given phenotype and study design. The fitness and performance map now includes 214 autosomal gene entries and quantitative trait loci plus seven others on the X chromosome. Moreover, there are 18 mitochondrial genes that have been shown to influence fitness and performance phenotypes. Thus,the map is growing in complexity. Although the map is exhaustive for currently published accounts of genes and exercise associations and linkages, there are undoubtedly many more gene-exercise interaction effects that have not even been considered thus far. Finally, it should be appreciated that most studies reported to date are based on small sample sizes and cannot therefore provide definitive evidence that DNA sequence variants in a given gene are reliably associated with human variation in fitness and performance traits.

Elevated ACE activity is not associated with asthma, COPD, and COPD co-morbidity

The angiotensin-converting enzyme (ACE) gene is a potential candidate gene for risk of asthma, COPD, and COPD co-morbidity. In 9034 Danish adults, we determined whether individuals homozygous or heterozygous for the ACE D allele are at greater risk of asthma, COPD, or COPD co-morbidity compared with ACE II homozygous individuals. In the general population, serum ACE activity increased with the number of D alleles (Kruskal-Wallis ANOVA: II vs. ID, p<0.001; ID vs. DD, p<0.001); however, this did not translate into altered risk of asthma or COPD. In the general population, the odds ratio (95% confidence interval) for asthma was 1.2 (0.9-1.4) for ID individuals and 1.2 (0.9-1.5) for DD individuals compared with II individuals. In the general population, the odds ratio for COPD was 0.9 (0.8-1.1) for ID individuals and 1.0 (0.8-1.2) for DD individuals compared with II individuals. Among patients with COPD, the odds ratio for ischemic heart disease was 1.1 (0.8-1.6) for ID individuals and 1.2 (0.8-1.7) for DD individuals compared with II individuals; corresponding odds ratios for hypertension were 1.1 (0.7-1.5) and 0.8 (0.5-1.2), and for low physical activity 0.9 (0.5-1.4) and 0.7 (0.4-1.2). The results were similar upon adjustment for sex, age, smoking status, body mass index, total cholesterol, and ACE inhibitor/angiotensin II type 1 receptor blocker use. These data suggest that lifelong genetically elevated ACE activity is not a major risk factor for asthma or COPD, or for ischemic heart disease, hypertension, and low physical activity in COPD patients.

The cerebral effects of ascent to high altitudes

Cellular hypoxia is the common final pathway of brain injury that occurs not just after asphyxia, but also when cerebral perfusion is impaired directly (eg, embolic stroke) or indirectly (eg, raised intracranial pressure after head injury). We Review recent advances in the understanding of neurological clinical syndromes that occur on exposure to high altitudes, including high altitude headache (HAH), acute mountain sickness (AMS), and high altitude cerebral oedema (HACE), and the genetics, molecular mechanisms, and physiology that underpin them. We also present the vasogenic and cytotoxic bases for HACE and explore venous hypertension as a possible contributory factor. Although the factors that control susceptibility to HACE are poorly understood, the effects of exposure to altitude (and thus hypobaric hypoxia) might provide a reproducible model for the study of cerebral cellular hypoxia in healthy individuals. The effects of hypobaric hypoxia might also provide new insights into the understanding of hypoxia in the clinical setting.

Keeping pace with ACE: are ACE inhibitors and angiotensin II type 1 receptor antagonists potential doping agents?

In the decade since the angiotensin-converting enzyme (ACE) gene was first proposed to be a 'human gene for physical performance', there have been numerous studies examining the effects of ACE genotype on physical performance phenotypes such as aerobic capacity, muscle function, trainability, and athletic status. While the results are variable and sometimes inconsistent, and corroborating phenotypic data limited, carriers of the ACE 'insertion' allele (the presence of an alu repeat element in intron 16 of the gene) have been reported to have higher maximum oxygen uptake (VO2max), greater response to training, and increased muscle efficiency when compared with individuals carrying the 'deletion' allele (absence of the alu repeat). Furthermore, the insertion allele has been reported to be over-represented in elite athletes from a variety of populations representing a number of endurance sports. The mechanism by which the ACE insertion genotype could potentiate physical performance is unknown. The presence of the ACE insertion allele has been associated with lower ACE activity (ACEplasma) in number of studies, suggesting that individuals with an innate tendency to have lower ACE levels respond better to training and are at an advantage in endurance sporting events. This could be due to lower levels of angiotensin II (the vasoconstrictor converted to active form by ACE), higher levels of bradykinin (a vasodilator degraded by ACE) or some combination of the two phenotypes. Observations that individuals carrying the ACE insertion allele (and presumably lower ACEplasma) have an enhanced response to training or are over-represented amongst elite athletes raises the intriguing question: would individuals with artificially lowered ACEplasma have similar training or performance potential? As there are a number of drugs (i.e. ACE inhibitors and angiotensin II type 1 receptor antagonists [angiotensin receptor blockers--ARBs]) that have the ability to either reduce ACEplasma activity or block the action of angiotensin II, the question is relevant to the study of ergogenic agents and to the efforts to rid sports of 'doping'. This article discusses the possibility that ACE inhibitors and ARBs, by virtue of their effects on ACE or angiotensin II function, respectively, have performance-enhancing capabilities; it also reviews the data on the effects of these medications on VO2max, muscle composition and endurance capacity in patient and non-patient populations. We conclude that, while the direct evidence supporting the hypothesis that ACE-related medications are potential doping agents is not compelling, there are insufficient data on young, athletic populations to exclude the possibility, and there is ample, albeit indirect, support from genetic studies to suggest that they should be. Unfortunately, given the history of drug experimentation in athletes and the rapid appropriation of therapeutic agents into the doping arsenal, this indirect evidence, coupled with the availability of ACE-inhibiting and ACE-receptor blocking medications may be sufficiently tempting to unscrupulous competitors looking for a shortcut to the finish line.

McArdle disease: what do neurologists need to know?

McArdle disease (also known as glycogen storage disease type V) is a pure myopathy caused by an inherited deficit of myophosphorylase, the skeletal muscle isoform of the enzyme glycogen phosphorylase. The disease exhibits clinical heterogeneity, but patients typically experience exercise intolerance, that is, reversible, acute crises (early fatigue and contractures, sometimes with rhabdomyolysis and myoglobinuria) triggered by static muscle contractions (e.g. lifting weights) or dynamic exercise (e.g. climbing stairs or running). In this Review, we discuss the main features of McArdle disease, with the aim of providing neurologists with up-to-date, useful information to assist their patients. The topics covered include diagnostic tools-for example, molecular genetic diagnosis, the classic ischemic forearm test and the so-called 'second wind' phenomenon-and current therapeutic options-for example, a carbohydrate-rich diet and carbohydrate ingestion shortly before strenuous exercise, in combination with medically supervised aerobic training of low to moderate intensity.

Association between angiotensin-converting enzyme gene polymorphisms and exercise performance in patients with COPD

BACKGROUND AND OBJECTIVE

Recent studies have shown that polymorphisms of the angiotensin-converting enzyme (ACE) gene are closely associated with pulmonary disorders. The ACE gene is involved in the regulation of inflammatory reactions to lung injury, respiratory drive, erythropoiesis and tissue oxygenation. The hypothesis for this study was that the ACE gene may be associated with the ventilatory response to exercise and the aerobic work efficiency of skeletal muscle in patients with COPD.

METHODS

Sixty-one Chinese Han COPD patients and 57 healthy control subjects performed incremental cardiopulmonary exercise testing on a cycle ergometer. ACE genotypes were determined using PCR amplification.

RESULTS

Resting lung function and blood gas index were not significantly different among the three ACE genotype COPD groups. Similarly, there were no significant differences in AT, maximal O(2) uptake, maximal O(2) pulse, maximal dyspnoea index, ventilatory response (DeltaVE/DeltaVCO(2)), O(2) cost of ventilation (VO(2)/W/VE), end-tidal partial pressure of carbon dioxide at maximal exercise and maximal SaO(2) among the three ACE genotype COPD patients. Maximal work load and aerobic work efficiency were higher in the COPD group with the II genotype than in those with the ID or DD genotype. There were no significant differences in resting lung function and cardiopulmonary exercise testing parameters among the three ACE genotype control groups.

CONCLUSIONS

The ACE gene may be involved in the regulation of skeletal muscle aerobic work efficiency, but is not associated with the ventilatory responses to exercise in COPD patients.

Similarity of polygenic profiles limits the potential for elite human physical performance

Human physical capability is influenced by many environmental and genetic factors, and it is generally accepted that physical capability phenotypes are highly polygenic. However, the ways in which relevant polymorphisms combine to influence the physical capability of individuals and populations are unknown. Initially, the literature was searched to identify associations between 23 genetic polymorphisms and human endurance phenotypes. Next, typical genotype frequencies of those polymorphisms in the general population were obtained from suitable literature. Using probability calculations, we found only a 0.0005% chance of a single individual in the world having the 'preferable' form of all 23 polymorphisms. As the number of DNA variants shown to be associated with human endurance phenotypes continues to increase, the probability of any single individual possessing the 'preferable' form of each polymorphism will become even lower. However, with population turnover, the chance of such genetically gifted individuals existing increases. To examine the polygenic endurance potential of a human population, a 'total genotype score' (for the 23 polymorphisms) was calculated for each individual within a hypothetical population of 1000 000. There was considerable homogeneity in terms of genetic predisposition to high endurance potential, with 99% of people differing by no more than seven genotypes from the typical profile. Consequently, with population turnover world and Olympic records should improve even without further enhancement of environmental factors, as more 'advantageous' polygenic profiles occasionally, though rarely, emerge. More broadly, human potential appears limited by the similarity of polygenic profiles at both the 'elite sport' and 'chronic disorder' ends of the performance continuum.

Genotype modulators of clinical severity in McArdle disease

The phenotypic manifestation of McArdle disease varies considerably from one individual to the next. The purpose of this study was to assess the possible association between the clinical severity of the disease, and each of the genotypes PYGM (R50X), ACE (I/D), AMPD1 (Q12X), PPARGC1A (G482S) and ACTN3 (R577X). We also assessed links between clinical disease severity and other potential phenotype modulators such as age or gender. McArdle disease was diagnosed in 99 patients of Spanish origin (60 male, 39 female; age range 8-81 years) by identifying the two mutant alleles of the PYGM gene. Disease severity was assessed using the grading scheme previously reported by Martinuzzi et al. [A. Martinuzzi, E. Sartori, M. Fanin, et al., Phenotype modulators in myophosphorylase deficiency, Ann. Neurol. 53 (2003) 497-502]. Significant correlation was observed (exact two-sided P<0.0001) between the number of D alleles of the ACE gene and the disease severity score. Rank-order correlation coefficients were 0.296 (95% CI: 0.169, 0.423) (Kendall's tau) and 0.345 (95% CI: 0.204, 0.486) (Somer's D). No significant relationships were detected between clinical severity and the remaining genotypes examined. Finally, disease severity was significantly worse in women with the disease. Our findings indicate that both ACE genotype and gender contribute to how McArdle disease manifests in an individual patient. The role of other candidate genes remains to be elucidated.

Polimorfismos genéticos determinantes da performance física em atletas de elite

Este artigo direciona-se à revisão de publicações sobre os "genes candidatos" e sua relação com os fenótipos de performance física humana em atletas de elite. Nosso objetivo é trazer ao conhecimento do leitor informações atualizadas sobre marcadores e variantes genéticas que podem levar certos indivíduos a sobressair-se em modalidades esportivas específicas. Além disso, serão descritos os mecanismos pelos quais um gene pode contribuir para a performance física, detalhando em cada momento as propriedades celulares, fisiológicas e moleculares do sistema em questão. Por esse motivo, limitamos nossa discussão a um número pequeno de variantes genéticas: polimorfismos R577X do gene da alfa-actinina 3 (ACTN3), C34T do gene da AMP deaminase (AMPD1), I/D da enzima conversora de angiotensina (ECA), -9/+9 do receptor beta2 de bradicinina (BDKRB2) e 985+185/1170 do gene da enzima creatina quinase M (CK-M). Esperamos com este artigo informar e sensibilizar o leitor para o fato de que a identificação de talentos e a otimização do potencial individual do atleta, com conseqüente sucesso no esporte, estão diretamente associados a variantes genéticas.

Do Angiotensin-Converting Enzyme (ACE) Inhibitors Enhance the Effect of Exercise Rehabilitation in Patients With Hypertension and ACE DD and DI Genotypes?

OBJECTIVE

To test whether pharmacologic angiotensin-converting enzyme (ACE) inhibition in carriers of the ACE DD or DI (D, deletion; I, insertion of 287 base pairs) genotypes can simulate the genetic advantage of the II genotype and thereby enhance the conditioning effects of aerobic exercise.

DESIGN

Nonrandomized controlled trial.

SETTING

Pulmonary institute.

PARTICIPANTS

Twelve sedentary men with controlled hypertension (5 with DD genotype, 7 with DI genotype; age, 53+/-7y) treated by ACE inhibitors (study group) and 10 patients (8 men, 2 women; 2 with DD genotype, 8 with DI genotype; age, 54+/-10y) who were treated by other antihypertensive drugs (controls).

INTERVENTION

Exercise training.

MAIN OUTCOME MEASURES

Training effect was measured by maximal oxygen uptake (Vo(2)max) anaerobic threshold (Vo(2AT)), and the corresponding work rates (WR) (in watts)-WRmax and WR(AT)-before and after 10 weeks of training.

RESULTS

Vo(2)max increased by a mean of 10% (200mL/min) and WRmax by 14% (25W) in each group (P<.001). Vo(2AT) and WR(AT) tended to increase more in the study group (Vo(2AT): 10% [186+/-35mL/min] vs 5% [100+/-1mL/min]; P<.006; WR(AT): 19% [19+/-2W] vs 12% [11+/-3W]; P<.03; respectively).

CONCLUSIONS

This study did not show an enhancement of exercise-related conditioning by pharmacologic ACE inhibition among hypertensive patients with ACE DD and DI genotypes, comparable to the advantage conferred by the II genotype.

The human gene map for performance and health-related fitness phenotypes: the 2005 update

The current review presents the 2005 update of the human gene map for physical performance and health-related fitness phenotypes. It is based on peer-reviewed papers published by the end of 2005. The genes and markers with evidence of association or linkage with a performance or fitness phenotype in sedentary or active people, in adaptation to acute exercise, or for training-induced changes are positioned on the genetic map of all autosomes and the X chromosome. Negative studies are reviewed, but a gene or locus must be supported by at least one positive study before being inserted on the map. By the end of 2000, in the early version of the gene map, 29 loci were depicted. In contrast, the 2005 human gene map for physical performance and health-related phenotypes includes 165 autosomal gene entries and QTL, plus five others on the X chromosome. Moreover, there are 17 mitochondrial genes in which sequence variants have been shown to influence relevant fitness and performance phenotypes. Thus, the map is growing in complexity. Unfortunately, progress is slow in the field of genetics of fitness and performance, primarily because the number of laboratories and scientists focused on the role of genes and sequence variations in exercise-related traits continues to be quite limited.

Small gene effect and exercise training-induced cardiac hypertrophy in mice: an Ace gene dosage study

Small gene effects influence complex phenotypes in a context dependent manner. Here we evaluated whether increasing dosage of the angiotensin I converting enzyme ( Ace) gene influence exercise-induced cardiac hypertrophy. Mice harboring one, two, three, and four copies of the Ace gene were assigned to sedentary (S1–4) and swimming exercise-trained (T1–4) groups (1.5 h twice daily, 5 days/wk, 4 wk). Exercising resulted in comparable bradycardia and elevated skeletal muscle citrate synthase activity, while blood pressure remained unchanged. Left ventricle mass index and cardiomyocyte diameter were similar among sedentary mice and the magnitude of their increase associated to exercising was not influenced by the Ace genotype (T1: 12.6 and 17.9%, T2: 15.2 and 13.8%, T3: 16.9 and 20%, T4: 17 and 19%, respectively). Plasma renin activity (PRA) levels were higher in one vs. three or four copies mice (4.89 ± 0.5 vs. 2.43 ± 0.6 and 2.12 ± 01.1 ng/ml Ang I, P < 0.05), while cardiac ACE activity was higher in three vs. two or one copy mice (5,946 ± 590.8 vs. 2,951.5 ± 328.3 and 3,504.1 ± 258.9 μF·min−1·ml−1, P < 0.05). With exercise, PRA remained unchanged in each group, while cardiac immunostaining for Ang II reached comparable levels. In summary: 1) exercise training led to similar aerobic adaptation regardless of the Ace genotype, and 2) higher number of Ace gene copies per se, which alters cardiac ACE activity, did not influence basal cardiac mass or, most importantly, the magnitude of swimming-induced cardiac hypertrophy. Collectively, these data indicate that small isolated genetic disturbances in ACE cardiac levels can be well compensated under physiological perturbations.

No correlation between circulating ACE activity and $$ {\user2{V}}{\mathbf{O}}_{{{\mathbf{2}}_{{{\mathbf{max}}}} }} $$ or mechanical efficiency in women

The insertion (I) variant of the angiotensin-1 converting enzyme (ACE) I/D genetic polymorphism is associated with lower circulating and tissue ACE activity. Some studies have also suggested associations of ACE I/D genotype with endurance phenotypes. This study assessed the relationships between circulating ACE activity, ACE I/D genotype, mechanical efficiency and the maximal rate of oxygen uptake in sedentary individuals. Sixty-two untrained women were tested for mechanical efficiency during submaximal cycle ergometry (delta and gross efficiencies during exercise between 40 and 80 W) and the maximal rate of oxygen uptake during incremental treadmill running. Respiratory variables were measured using indirect calorimetry. Venous blood was obtained for direct assay of circulating ACE activity, allowing for the assessment of correlations between two continuous variables, rather than a categorical analysis of endurance phenotype by genotype alone. ACE I/D genotype was also determined, and was strongly associated with circulating ACE activity (P < 0.0005). Neither circulating ACE activity (27.4 +/- 8.4 nM His-Leu-ml(-1)) nor ACE genotype showed a statistically significant association with any of the endurance phenotypes measured. The weak correlations observed included r = -0.122 (P = 0.229) for the relationship between delta efficiency (23.9 +/- 2.5%) and circulating ACE activity and r = 0.134 (P > 0.6) for the relationship between maximal aerobic power (149.1 +/- 22.9 ml kg(-2/3) min(-1)) and circulating ACE activity. The data do not support a role for systemic ACE activity in the regulation of endurance performance in sedentary individuals, extending this observation to a large female cohort.

Biomechanical muscle properties and angiotensin-converting enzyme gene polymorphism: a model-based study

Previous studies reported an association of angiotensin-converting enzyme (ACE) I/D gene polymorphism with physical performance. The study was based on the hypothesis that certain individual biomechanical muscle properties could be associated with ACE genotype and that they could influence athletes' physical performance. Movement-independent individual biomechanical muscle properties of 62 sports students were determined by applying a mathematical model to experimental data. Subjects exerted concentric and isometric contractions at a leg-press. The model was based on a Hill-type muscle model, a function describing the geometrical arrangement of human leg extensor muscles, and an exponential function describing muscle activation. Mouthwash samples were taken to determine the ACE genotypes. Several combinations of experimentally determined biomechanical properties served as input variables for a discriminant analysis. We were able to show that individual biomechanical muscle properties correlated with ACE I/D gene polymorphism. With a combination of certain individual muscle parameters based on a Hill-type muscle model, we were able to separate three individual ACE genotypes (II, ID, DD) in a significant way (P<0.03) and correctly classify 89% of the cases using a discriminant analysis. We conclude that local biomechanical muscle properties are influenced by ACE genotype.