The Role of Genetics in Moderating the Inter-Individual Differences in the Ergogenicity of Caffeine

Caffeine use is widespread among athletes following its removal from the World Anti-Doping Agency banned list, with approximately 75% of competitive athletes using caffeine. While literature supports that caffeine has a small positive ergogenic effect for most forms of sports and exercise, there exists a significant amount of inter-individual difference in the response to caffeine ingestion and the subsequent effect on exercise performance. In this narrative review, we discuss some of the potential mechanisms and focus on the role that genetics has in these differences. CYP1A2 and ADORA2A are two of the genes which are thought to have the largest impact on the ergogenicity of caffeine. CYP1A2 is responsible for the majority of the metabolism of caffeine, and ADORA2A has been linked to caffeine-induced anxiety. The effects of CYP1A2 and ADORA2A genes on responses to caffeine will be discussed in detail and an overview of the current literature will be presented. The role of these two genes may explain a large portion of the inter-individual variance reported by studies following caffeine ingestion. Elucidating the extent to which these genes moderate responses to caffeine during exercise will ensure caffeine supplementation programs can be tailored to individual athletes in order to maximize the potential ergogenic effect.

Inter-individual variation in adaptations to endurance and resistance exercise training: genetic approaches towards understanding a complex phenotype

Exercise training which meets the recommendations set by the National Physical Activity Guidelines ensues a multitude of health benefits towards the prevention and treatment of various chronic diseases. However, not all individuals respond well to exercise training. That is, some individuals have no response, while others respond poorly. Genetic background is known to contribute to the inter-individual (human) and -strain (e.g., mice, rats) variation with acute exercise and exercise training, though to date, no specific genetic factors have been identified that explain the differential responses to exercise. In this review, we provide an overview of studies in human and animal models that have shown a significant contribution of genetics in acute exercise and exercise training-induced adaptations with standardized endurance and resistance training regimens, and further describe the genetic approaches which have been used to demonstrate such responses. Finally, our current understanding of the role of genetics and exercise is limited primarily to the nuclear genome, while only a limited focus has been given to a potential role of the mitochondrial genome and its interactions with the nuclear genome to predict the exercise training-induced phenotype(s) responses. We therefore discuss the mitochondrial genome and literature that suggests it may play a significant role, particularly through interactions with the nuclear genome, in the inherent ability to respond to exercise.

High prevalence of the IGF2 rs680 GG polymorphism among top-level sprinters and jumpers

Previous studies have shown that the IGF1 polymorphism is associated with greater muscle mass and improved power athletic ability, but very little is known about the IGF2 polymorphism and athletic performance.

PURPOSE

The aim of the present study was to assess the frequency distribution of the IGF2 rs680 polymorphism among Israeli athletes.

METHODS

185 short- (n=72) and long-distance (n=113) runners, 94 short- (n=44) and long-distance (n=50) swimmers, 54 weight lifters and 111 controls participated in the study. Genomic DNA was extracted from peripheral EDTA treated anti-coagulated blood using a standard protocol. Genotyping of the IGF2 A/G polymorphism (rs680) was performed using allelic discrimination assay.

RESULTS

The frequency of IGF2 (rs680) G allele carriers was significantly greater among top compared to national-level track and field sprinters and jumpers (p<0.05). The IGF2 (rs680) GG genotype frequency was significantly greater among track and field sprinters and jumpers compared to weight lifters p<0.02), and among top-level sprinters and jumpers compared to top-level weight lifters p<0.01). There were no statistically significant differences in the IGF2 (rs680) GG genotype frequency among endurance athletes and between the swimmers and the other sports disciplines and the controls.

CONCLUSIONS

While a single polymorphism cannot determine athletic success or failure, the findings of the present study suggest a potential importance of the IGF2 polymorphism, mainly regarding speed sport performance.

Acute effects of strength exercises and effects of regular strength training on cell free DNA concentrations in blood plasma

Creatine kinase (CK) is a marker for muscle cell damage with limited potential as marker for training load in strength training. Recent exercise studies identified cell free DNA (cfDNA) as a marker for aseptic inflammation and cell damage. Here we overserved in a pilot study the acute effects during strength exercise and chronic effects of regular strength training on cfDNA concentrations over a period of four weeks in three training groups applying conservation training (CT) at 60% of the 1 repetition maximum, high intensity-low repetition training (HT) at 90% of the 1 repetition maximum and differential training (DT) at 60% of the 1 repetition maximum. EDTA-plasma samples were collected before every training session, and on the first and last training day repeatedly after every set of exercises. CfDNA increased significantly by 1.62-fold (mean (±SD) before first exercise: 8.31 (2.84) ng/ml, after last exercise 13.48 (4.12) ng/ml) across all groups within a single training session (p<0.001). The increase was 1.77-fold higher (mean (±SD) before first exercise: 12.23 (6.29) ng/ml, after last exercise 17.73 (11.24) ng/ml) in HT compared to CT (mean (±SD) before first exercise: 6.79 (1.28) ng/ml, after last exercise 10.05 (2.89) ng/ml) (p = 0.01). DNA size analysis suggested predominant release of short, mononucleosomal DNA-fragments in the acute exercise setting, while we detected an increase of mostly longer, polynucleosomal cfDNA-fragments at rest before the training session only at day two with a subsequent return to baseline (p<0.001). In contrast, training procedures did not cause any alterations in CK. Our results suggest that during strength exercise short-fragmented cfDNA is released, reflecting a fast, aseptic inflammatory response, while elevation of longer fragments at baseline on day two seemed to reflect mild cellular damage due to a novel training regime. We critically discuss the implications of our findings for future evaluations of cfDNA as a marker for training load in strength training.

Differences in echocardiography, blood pressure, stroke volume, maximal power and profile of genes related to cardiac hypertrophy in elite road cyclists

BACKGROUND

Regular and moderate exercise is beneficial for improving the efficiency of the heart, but high-intensity physical activity may result in cardiac changes.

OBJECTIVES

This study focuses on the identification of the differences in echocardiography and blood variables before exercise, as well as the genes associated with cardiac hypertrophy at rest and in response to graded exercise test.

MATERIAL AND METHODS

The study group was made up of 28 road cyclists. Echocardiographic parameters and blood pressure were measured before exercise tests (N = 28). Blood samples were collected at rest, at maximal exercise intensity in a graded bicycle test and after 15 min of recovery; afterwards, blood morphology was estimated and RNA was isolated. Analysis of the expression profile of genes was performed for randomly selected road cyclists using the microarray method.

RESULTS

Echocardiographic results and blood parameters divided cyclists into two groups: with and without left ventricular hypertrophy (N = 14). Differences in the structure and function of the left ventricle cyclists with a similar level of training were observed (p < 0.05). Diastolic blood pressure and resting heart rate were significantly lower in subjects with left ventricular hypertrophy (p < 0.05). The myosin light chain 9 and interleukin-6 signal transducer gene expression were differentially regulated in cyclists with left ventricular hypertrophy compared to athletes with normal heart dimensions in response to intensive exercise.

CONCLUSIONS

We have found differences in echocardiography parameters, blood pressure, stroke volume and maximal power in the cyclists examined. These studies indicate the benefits of the recommended echocardiography measurements for professional endurance-athletes. The graded exercise altered the myosin light chain 9 and interleukin-6 signal transducer gene expression in the peripheral blood of road cyclists has also been found.

Genomic and transcriptomic predictors of response levels to endurance exercise training

Predicting the responsiveness to regular exercise is a topic of great relevance due to its potential role in personalized exercise medicine applications. The present review focuses on cardiorespiratory fitness (commonly measured by maximal oxygen uptake, V̇O2 max ), a trait with wide-ranging impact on health and performance indicators. Gains in V̇O2 max demonstrate large inter-individual variation even in response to standardized exercise training programmes. The estimated ΔVO2 max heritability of 47% suggests that genomic-based predictors alone are insufficient to account for the total trainability variance. Candidate gene and genome-wide linkage studies have not significantly contributed to our understanding of the molecular basis of trainability. A genome-wide association study suggested that V̇O2 max trainability is influenced by multiple genes of small effects, but these findings still await rigorous replication. Valuable evidence, however, has been obtained by combining skeletal muscle transcript abundance profiles with common DNA variants for the prediction of the V̇O2 max response to exercise training. Although the physiological determinants of V̇O2 max measured at a given time are largely enunciated, what is poorly understood are the details of tissue-specific molecular mechanisms that limit V̇O2 max and related signalling pathways in response to exercise training. Bioinformatics explorations based on thousands of variants have been used to interrogate pathways and systems instead of single variants and genes, and the main findings, along with those from exercise experimental studies, have been summarized here in a working model of V̇O2 max trainability.

Dissociation of muscle insulin sensitivity from exercise endurance in mice by HDAC3 depletion

Type 2 diabetes and insulin resistance are associated with reduced glucose utilization in the muscle and poor exercise performance. Here we find that depletion of the epigenome modifier histone deacetylase 3 (HDAC3) specifically in skeletal muscle causes severe systemic insulin resistance in mice but markedly enhances endurance and resistance to muscle fatigue, despite reducing muscle force. This seemingly paradoxical phenotype is due to lower glucose utilization and greater lipid oxidation in HDAC3-depleted muscles, a fuel switch caused by the activation of anaplerotic reactions driven by AMP deaminase 3 (Ampd3) and catabolism of branched-chain amino acids. These findings highlight the pivotal role of amino acid catabolism in muscle fatigue and type 2 diabetes pathogenesis. Further, as genome occupancy of HDAC3 in skeletal muscle is controlled by the circadian clock, these results delineate an epigenomic regulatory mechanism through which the circadian clock governs skeletal muscle bioenergetics. These findings suggest that physical exercise at certain times of the day or pharmacological targeting of HDAC3 could potentially be harnessed to alter systemic fuel metabolism and exercise performance.

ACTN3/ACE genotypes and mitochondrial genome in professional soccer players’ performance

Two nuclear genes, ACTN3, encoding for the α-actinin skeletal muscle isoform 3, and ACE encoding the angiotensin-converting enzyme, have both been associated with quantitative physical performance traits in the general population. The purpose of our study was to assess the association between the two nuclear gene variants, R577X (rs1815739) in ACTN3 and I/D (rs4340) in ACE, with elite athletes’ performance and the effect of training on the mitochondrial DNA (mtDNA) content in peripheral blood. We evaluated the genotypes and frequencies of ACTN3 R577X and ACE I/D polymorphisms between soccer players (n = 43) and healthy non-athletic controls (n = 128). Total DNA was extracted from peripheral blood samples using the standard procedure. The genotypes were assessed by PCR-RFLP analysis and mtDNA cellular content by RT-PCR. The soccer players showed a tendency to a prevalence of ACTN3RR and ACEDD genotypes both independently and in co-occurrence. The effect of physical training on the mitochondrial DNA content in the athletic population was reflected strikingly in its increase in peripheral blood. Based on our results, we suggest that the analysis of ACTN3 and ACE genotypes could predict talent in the soccer field and that knowledge of the genetic variants could determine types and training times for soccer players. In addition, the novelty of this work, never before described in the sports literature, is that the increase of mitochondrial content can be correlated with the training load, suggesting that the mtDNA copy number may be considered a viable bioenergetics biomarker.

Adult expression of PGC-1α and -1β in skeletal muscle is not required for endurance exercise-induced enhancement of exercise capacity

Exercise has been shown to be the best intervention in the treatment of many diseases. Many of the benefits of exercise are mediated by adaptions induced in skeletal muscle. The peroxisome proliferator-activated receptor gamma coactivator-1 (PGC-1) family of transcriptional coactivators has emerged as being key mediators of the exercise response and is considered to be essential for many of the adaptions seen in skeletal muscle. However, the contribution of the PGC-1s in skeletal muscle has been evaluated by the use of either whole body or congenital skeletal muscle-specific deletion. In these models, PGC-1s were never present, thereby opening the possibility to developmental compensation. Therefore, we generated an inducible muscle-specific deletion of PGC-1α and -1β (iMyo-PGC-1DKO), in which both PGC-1α and -β can be deleted specifically in adult skeletal muscle. These iMyo-PGC-1DKO animals were used to assess the role of both PGC-1α and -1β in adult skeletal muscle and their contribution to the exercise training response. Untrained iMyo-PGC-1DKO animals exhibited a time-dependent decrease in exercise performance 8 wk postdeletion, similar to what was observed in the congenital muscle-specific PGC-1DKOs. However, after 4 wk of voluntary training, the iMyo-PGC-1DKOs exhibited an increase in exercise performance with a similar adaptive response compared with control animals. This increase was associated with an increase in electron transport complex (ETC) expression and activity in the absence of PGC-1α and -1β expression. Taken together these data suggest that PGC-1α and -1β expression are not required for training-induced exercise performance, highlighting the contribution of PGC-1-independent mechanisms.

Comparative analysis of hepatic miRNA levels in male marathon mice reveals a link between obesity and endurance exercise capacities

Dummerstorf marathon mice (DUhTP) are characterized by increased accretion of peripheral body fat with fast mobilization in response to mild physical activity if running wheels were included in their home cages. The obese phenotype coincides with elevated hepatic lipogenesis if compared to unselected controls. We now asked, if microRNA (miRNA) species present in the liver may contribute to the obese phenotype of DUhTP mice and if miRNAs respond to mild physical activity in our mouse model. Total RNA was extracted from livers of sedentary or physically active marathon mice and controls and analyzed by array hybridization or real-time PCR using locked nucleic acid probes. Pathway analysis of altered miRNA concentrations identified fatty acid biosynthesis as the most important target for the effects of miRNAs in the liver. A miRNA signature consisting of miR-21, 27, 33, 122, and 143 was present at higher abundance (p < 0.01) in the liver of sedentary or active DUhTP mice indicating involvement of miRNAs with hepatic lipogenesis. Furthermore, in protein lysates from the liver of DUhTP mice, significantly reduced concentrations of total and phosphorylated AKT and lower levels of phosphorylated AMPK were found (p < 0.05). Our results indicate active involvement of miRNAs in the control of hepatic energy metabolism and discuss effects on signal transduction as a potentially direct effect of miR-143 in the liver of DUhTP mice.

Prmt7 Deficiency Causes Reduced Skeletal Muscle Oxidative Metabolism and Age-Related Obesity

Maintenance of skeletal muscle function is critical for metabolic health and the disruption of which exacerbates many chronic diseases such as obesity and diabetes. Skeletal muscle responds to exercise or metabolic demands by a fiber-type switch regulated by signaling-transcription networks that remains to be fully defined. Here, we report that protein arginine methyltransferase 7 (Prmt7) is a key regulator for skeletal muscle oxidative metabolism. Prmt7 is expressed at the highest levels in skeletal muscle and decreased in skeletal muscles with age or obesity. Prmt7(-/-) muscles exhibit decreased oxidative metabolism with decreased expression of genes involved in muscle oxidative metabolism, including PGC-1α. Consistently, Prmt7(-/-) mice exhibited significantly reduced endurance exercise capacities. Furthermore, Prmt7(-/-) mice exhibit decreased energy expenditure, which might contribute to the exacerbated age-related obesity of Prmt7(-/-) mice. Similarly to Prmt7(-/-) muscles, Prmt7 depletion in myoblasts also reduces PGC-1α expression and PGC-1α-promoter driven reporter activities. Prmt7 regulates PGC-1α expression through interaction with and activation of p38 mitogen-activated protein kinase (p38MAPK), which in turn activates ATF2, an upstream transcriptional activator for PGC-1α. Taken together, Prmt7 is a novel regulator for muscle oxidative metabolism via activation of p38MAPK/ATF2/PGC-1α.

Genetics of Musculoskeletal Exercise-Related Phenotypes

Genetic factors have been shown to associate with various exercise-related phenotypes, including exercise performance, adaptation to training and sports injuries. The genes implicated in the pathogenesis of musculoskeletal soft-tissue injuries all code for either structural components or regulatory components of the extracellular matrix. It has been hypothesized that these genetic associations with injuries are due to genetically regulated changes in mechanical properties of musculoskeletal soft tissue. Thus, the objective of this review is to highlight the research which has advanced our understanding of how genetic variation within these structural genes affects the properties of our connective tissue. The genetics of various exercise-related phenotypes, such as range of motion, endurance performance and exercise-associated muscle cramps, are reviewed. Lastly, a model is presented where genetic variations within a collagen-encoding gene result in a continuum of phenotype ranging from a normal tissue to a seriously deleterious or lethal disorder.

Genes and Athletic Performance: An Update

Humans vary in their ability to achieve success in sports, and this variability mostly depends on genetic factors. The main goal of this work was to review the current progress in the understanding of genetic determinism of athlete status and to describe some novel and important DNA polymorphisms that may underlie differences in the potential to be an elite athlete. In the past 19 years, at least 155 genetic markers (located within almost all chromosomes and mtDNA) were found to be linked to elite athlete status (93 endurance-related genetic markers and 62 power/strength-related genetic markers). Importantly, 41 markers were identified within the last 2 years by performing genome-wide association studies (GWASs) of African-American, Jamaican, Japanese, and Russian athletes, indicating that GWASs represent a promising and productive way to study sports-related phenotypes. Of note, 31 genetic markers have shown positive associations with athlete status in at least 2 studies and 12 of them in 3 or more studies. Conversely, the significance of 29 markers was not replicated in at least 1 study, raising the possibility that several findings might be false-positive. Future research, including multicentre GWASs and whole-genome sequencing in large cohorts of athletes with further validation and replication, will substantially contribute to the discovery of large numbers of the causal genetic variants (mutations and DNA polymorphisms) that would partly explain the heritability of athlete status and related phenotypes.

ACVR1B rs2854464 Is Associated with Sprint/Power Athletic Status in a Large Cohort of Europeans but Not Brazilians

Skeletal muscle strength and mass, major contributors to sprint/power athletic performance, are influenced by genetics. However, to date, only a handful of genetic variants have been associated with sprint/power performance. The ACVR1B A allele (rs rs2854464) has previously been associated with increased muscle-strength in non-athletic cohort. However, no follow-up and/or replications studies have since been conducted. Therefore, the aim of the present study was to compare the genotype distribution of ACVR1B rs2854464 between endurance athletes (E), sprint/power (S/P) athletes, mixed athletes (M), and non-athletic control participants in 1672 athletes (endurance athletes, n = 482; sprint/power athletes, n = 578; mixed athletes, n = 498) and 1089 controls (C) of both European Caucasians (Italian, Polish and Russians) and Brazilians. We have also compared the genotype distribution according to the athlete's level of competition (elite vs. sub-elite). DNA extraction and genotyping were performed using various methods. Fisher's exact test (adjusted for multiple comparisons) was used to test whether the genotype distribution of rs2854464 (AA, AG and GG) differs between groups. The A allele was overrepresented in S/P athletes compared with C in the Caucasian sample (adjusted p = 0.048), whereas there were no differences in genotype distribution between E athletes and C, in neither the Brazilian nor the Caucasian samples (adjusted p > 0.05). When comparing all Caucasian athletes regardless of their sporting discipline to C, we found that the A allele was overrepresented in athletes compared to C (adjusted p = 0.024). This association was even more pronounced when only elite-level athletes were considered (adjusted p = 0.00017). In conclusion, in a relatively large cohort of athletes from Europe and South America we have shown that the ACVR1B rs2854464 A allele is associated with sprint/power performance in Caucasians but not in Brazilian athletes. This reinforces the notion that phenotype-genotype associations may be ethnicity-dependent.

Can genotype determine the sports phenotype? A paradigm shift in sports medicine

In last two decades, there has been an evolution in sports medicine. Several researchers have worked on different domains of sports medicine, like strength, endurance, sports injury, and psychology. Besides this, several groups have explored the changes at cellular and molecular levels during exercise, which has led to the development of the new domain in sports science known as genetic medicine. Genetic medicine deals with the genotypic basis of sports phenotype. In this article, we try to provide an up-to-date review on genetic determinants of sports performance, which will be like a journey from the nostalgic past towards the traditional present and the romantic future of sports medicine. Endurance and power performance are two important domains of athletes. They vary in individuals, even among trained athletes. Researches indicate that the genetic makeup of sportsmen play a vital role in their performance. Several genetic factors are reported to be responsible for endurance, power, susceptibility to injury, and even psychology of the individual. Besides this, proper training, nutrition, and environment are also important in shaping their potential. The aim of this discussion is to understand the influence of the environment and the genetic makeup on the performance of the athletes. There is sufficient evidence to suggest that genotype determines the sports phenotype in an athlete. Choosing the right sports activity based on genetic endowment is the key for achieving excellence in sports.

Genetic advantageous predisposition of angiotensin converting enzyme id polymorphism in Tunisian athletes

BACKGROUND

ID polymorphism of the gene coding for the angiotensin I-converting enzyme (ACE) represents a determining factor in physical and athletic performance in the context of genetic conditioning of sports predisposition. The aim of this study was to show the potential importance of genetic factors in relation to the athletic status in Tunisian athletes.

METHODS

The ACE genotypes were established using polymerase chain reaction (PCR) amplification for 282 Tunisian athletes (endurance: N.=149 - power: N.=133), and 211 sedentary volunteers.

RESULTS

No significant difference was found in the ACE genotype distribution between athletes (36% DD, 49% ID, 15% II) and controls (CTR) (39% DD, 46% ID, 15% II; P=0.72). In contrast, a high significant difference between endurance and power groups were noted in genotype and alleles (χ2=10.32, P=0.0057; χ2=4,752, P=0.029, respectively). The elite endurance-athletes (N.=72) possess some inherent genetic advantage predisposing them to superior athletic performances compared to CTR for ACE alleles (χ2=3.51, P=0.06). In addition endurance trained athletes were also significantly different from CTR for ACE genotype (χ2=6.05, P=0.04). Furthermore, a significant difference have been found between elite power-athletes (N.=59) and CTR for ACE alleles (χ2=3.79, P=0.05).

CONCLUSIONS

Tunisian athletes exhibit insertion (I) and deletion (D) alleles of the ACE polymorphism associated with a high level of human endurance and power performance, respectively. This genetic background plays an important role in sporting potential and causes some individuals to be better adapted to specific physical training. This should be considered in athlete development to identify which sporting specialties should be trained for Tunisian talent promotion.

Mechanisms of Attenuation of Pulmonary V'O2 Slow Component in Humans after Prolonged Endurance Training

In this study we have examined the effect of prolonged endurance training program on the pulmonary oxygen uptake (V'O2) kinetics during heavy-intensity cycling-exercise and its impact on maximal cycling and running performance. Twelve healthy, physically active men (mean±SD: age 22.33±1.44 years, V'O2peak 3198±458 mL ∙ min-1) performed an endurance training composed mainly of moderate-intensity cycling, lasting 20 weeks. Training resulted in a decrease (by ~5%, P = 0.027) in V'O2 during prior low-intensity exercise (20 W) and in shortening of τp of the V'O2 on-kinetics (30.1±5.9 s vs. 25.4±1.5 s, P = 0.007) during subsequent heavy-intensity cycling. This was accompanied by a decrease of the slow component of V'O2 on-kinetics by 49% (P = 0.001) and a decrease in the end-exercise V'O2 by ~5% (P = 0.005). An increase (P = 0.02) in the vascular endothelial growth factor receptor 2 mRNA level and a tendency (P = 0.06) to higher capillary-to-fiber ratio in the vastus lateralis muscle were found after training (n = 11). No significant effect of training on the V'O2peak was found (P = 0.12). However, the power output reached at the lactate threshold increased by 19% (P = 0.01). The power output obtained at the V'O2peak increased by 14% (P = 0.003) and the time of 1,500-m performance decreased by 5% (P = 0.001). Computer modeling of the skeletal muscle bioenergetic system suggests that the training-induced decrease in the slow component of V'O2 on-kinetics found in the present study is mainly caused by two factors: an intensification of the each-step activation (ESA) of oxidative phosphorylation (OXPHOS) complexes after training and decrease in the ''additional" ATP usage rising gradually during heavy-intensity exercise.

Analysis of the ACTN3 heterozygous genotype suggests that α-actinin-3 controls sarcomeric composition and muscle function in a dose-dependent fashion

A common null polymorphism (R577X) in ACTN3 causes α-actinin-3 deficiency in ∼ 18% of the global population. There is no associated disease phenotype, but α-actinin-3 deficiency is detrimental to sprint and power performance in both elite athletes and the general population. However, despite considerable investigation to date, the functional consequences of heterozygosity for ACTN3 are unclear. A subset of studies have shown an intermediate phenotype in 577RX individuals, suggesting dose-dependency of α-actinin-3, while others have shown no difference between 577RR and RX genotypes. Here, we investigate the effects of α-actinin-3 expression level by comparing the muscle phenotypes of Actn3(+/-) (HET) mice to Actn3(+/+) [wild-type (WT)] and Actn3(-/-) [knockout (KO)] littermates. We show reduction in α-actinin-3 mRNA and protein in HET muscle compared with WT, which is associated with dose-dependent up-regulation of α-actinin-2, z-band alternatively spliced PDZ-motif and myotilin at the Z-line, and an incremental shift towards oxidative metabolism. While there is no difference in force generation, HET mice have an intermediate endurance capacity compared with WT and KO. The R577X polymorphism is associated with changes in ACTN3 expression consistent with an additive model in the human genotype-tissue expression cohort, but does not influence any other muscle transcripts, including ACTN2. Overall, ACTN3 influences sarcomeric composition in a dose-dependent fashion in mouse skeletal muscle, which translates directly to function. Variance in fibre type between biopsies likely masks this phenomenon in human skeletal muscle, but we suggest that an additive model is the most appropriate for use in testing ACTN3 genotype associations.

MicroRNAs as Biomarkers for Acute Atrial Remodeling in Marathon Runners (The miRathon Study--A Sub-Study of the Munich Marathon Study)

Introduction

Physical activity is beneficial for individual health, but endurance sport is associated with the development of arrhythmias like atrial fibrillation. The underlying mechanisms leading to this increased risk are still not fully understood. MicroRNAs are important mediators of proarrhythmogenic remodeling and have potential value as biomarkers in cardiovascular diseases. Therefore, the objective of our study was to determine the value of circulating microRNAs as potential biomarkers for atrial remodeling in marathon runners (miRathon study).

Methods

30 marathon runners were recruited into our study and were divided into two age-matched groups depending on the training status: elite (ER, ≥55 km/week, n = 15) and non-elite runners (NER, ≤40 km/week, n = 15). All runners participated in a 10 week training program before the marathon. MiRNA plasma levels were measured at 4 time points: at baseline (V1), after a 10 week training period (V2), immediately after the marathon (V3) and 24h later (V4). Additionally, we obtained clinical data including serum chemistry and echocardiography at each time point.

Results

MiRNA plasma levels were similar in both groups over time with more pronounced changes in ER. After the marathon miR-30a plasma levels increased significantly in both groups. MiR-1 and miR-133a plasma levels also increased but showed significant changes in ER only. 24h after the marathon plasma levels returned to baseline. MiR-26a decreased significantly after the marathon in elite runners only and miR-29b showed a non-significant decrease over time in both groups. In ER miRNA plasma levels showed a significant correlation with LA diameter, in NER miRNA plasma levels did not correlate with echocardiographic parameters.

Conclusion

MiRNAs were differentially expressed in the plasma of marathon runners with more pronounced changes in ER. Plasma levels in ER correlate with left atrial diameter suggesting that circulating miRNAs could potentially serve as biomarkers of atrial remodeling in athletes.

No Evidence of a Common DNA Variant Profile Specific to World Class Endurance Athletes

There are strong genetic components to cardiorespiratory fitness and its response to exercise training. It would be useful to understand the differences in the genomic profile of highly trained endurance athletes of world class caliber and sedentary controls. An international consortium (GAMES) was established in order to compare elite endurance athletes and ethnicity-matched controls in a case-control study design. Genome-wide association studies were undertaken on two cohorts of elite endurance athletes and controls (GENATHLETE and Japanese endurance runners), from which a panel of 45 promising markers was identified. These markers were tested for replication in seven additional cohorts of endurance athletes and controls: from Australia, Ethiopia, Japan, Kenya, Poland, Russia and Spain. The study is based on a total of 1520 endurance athletes (835 who took part in endurance events in World Championships and/or Olympic Games) and 2760 controls. We hypothesized that world-class athletes are likely to be characterized by an even higher concentration of endurance performance alleles and we performed separate analyses on this subsample. The meta-analysis of all available studies revealed one statistically significant marker (rs558129 at GALNTL6 locus, p = 0.0002), even after correcting for multiple testing. As shown by the low heterogeneity index (I2 = 0), all eight cohorts showed the same direction of association with rs558129, even though p-values varied across the individual studies. In summary, this study did not identify a panel of genomic variants common to these elite endurance athlete groups. Since GAMES was underpowered to identify alleles with small effect sizes, some of the suggestive leads identified should be explored in expanded comparisons of world-class endurance athletes and sedentary controls and in tightly controlled exercise training studies. Such studies have the potential to illuminate the biology not only of world class endurance performance but also of compromised cardiac functions and cardiometabolic diseases.

[Association of CKMM gene A/G polymorphism and athletic performance of uyghurnationality]

OBJECTIVE

Discusses the distributive characters of the Creatine Kinase MM (CKMM) gene A/G Polymorphism in XinjiangUyghur, One hundred and fourtheen athletes and 441 general population of Uyghur were involved in the study.

METHODS

Polymerase chain reaction-restriction fragment length polymorphism was used.

RESULTS

(1) The CKMM gene A/G frequency in Uyghur general population was(AA, AG and GG) 0.497, 0.392 and 0.111, the result test by Hardy-Weinberg (H-W) equilibrium and x² = 2.72, P = 0.1, df = 2, indicated that the control group had representative. (2) AA, AG and GG genotype frequency of power-oriented athlete respectively was 0.442,0.302 and 0.256, frequency of GG genotype and G allele was higher than the control group, there were significant differences compared to thecontrol( P < 0.05, df = 2); (3) A/G genotype frequency of Endurance-oriented athletere spectively was 0.571, 0.400 and 0.029, there were nosignificant differences compared to the controls ( P > 0. 05, df = 2). (4) A/G genotype frequency of Uyghur soccer athletes respectively was0.472, 0.361 and 0.167, G allele was higher than the Endurance-oriented athlete and lower than the power-oriented athletes. and no significant differences compared to the controls( P > 0.05, df = 2).

CONCLUSION

The results indicate that the CKMM gene GG genotype and G alleleare represented in power-oriented athletes, but don't find A/G polymorphism correlation with endurance and the football sport performance.

rs6295 [C]-Allele Protects Against Depressive Mood in Elderly Endurance Athletes

A single nucleotide variant within the promoter of the 5-hydroxytryptamine1A (5HT1A) receptor, rs6295, is part of a binding site for the transcription factor. We aimed to ascertain whether the rs6295 mediates the effect of exercise on depressive mood in elderly endurance athletes. We prospectively enrolled 55 elderly athletes (marathon runners/bicyclists) and 58 controls. In a controlled, univariate model, an interaction between the [C]-allele and physical activity indicated that only among athletes, the variant resulting in an imperfect NUDR binding site was associated with a lower depression score. Hence, athletes presented with a significantly lower relative risk of achieving a suspicious depression score among carriers of at least one [C]-allele. Our results suggest that the positive effect of physical exercise on depressive mood might be mediated by the 5HT1A receptor and the extent of this protective effect seems to be enhanced by the [C]-allele of the rs6295 variant.

[THE INFLUENCE OF SEROTONIN TRANSPORTER AND MONOAMINE OXIDASE A GENES POLYMORPHISM ON PSYCHO-EMOTION AND KARYOLOGICAL STABILITY OF ATHLETES]

The influence of polymorphism of the serotonin transporter and monoamine oxidase A genes, associated with man's aggressiveness on the psycho-emotional state and karyological status of single combat athletes. It was revealed that the carriers of less active ("short"), monoamine oxidase A gene variant have a high motivation to succeed and less rigidity and frustrated, compared to the carriers of more active ("long") version of the gene. Heterozygote carriers of less active ("short") variant of the serotonin transporter gene 5-HTTL had more physical aggression, guilt and were less frustrated compared with carriers of two long alleles. It has been revealed the association of studied genes with the karyological status of athletes. So fighters who are carriers of the short and long alleles of the serotonin transporter gene had more cells with nuclear abnormalities in the buccal epithelium than single combat athletes which both alleles were long.

Curcumin treatment enhances the effect of exercise on mitochondrial biogenesis in skeletal muscle by increasing cAMP levels

BACKGROUND

In response to physiologic stressors, skeletal muscle has the potential to elicit wide variety of adaptive responses, such as biogenesis of mitochondria and clearance of damaged mitochondria to promote healthy muscle. The polyphenol curcumin, derived from the rhizome Curcuma longa L., is a natural antioxidant that exhibits various pharmacological activities and therapeutic properties. However, the effect of curcumin on the regulation of mitochondrial biogenesis in skeletal muscle remains unknown. The present study aimed to examine the effects of combination of endurance training (eTR) and curcumin treatment on the expression of AMPK, SIRT1, PGC-1α, and OXPHOS subunits, mitochondrial DNA copy number, and CS activity in rat skeletal muscle. Furthermore, the present study also examined the effect of exercise and curcumin treatment on the levels of cAMP and downstream targets of PKA including phosphorylated CREB and LKB-1.

METHODS

Ten-week-old male Wistar rats were randomly divided into non-eTR and eTR groups. Low doses (50 mg/kg-BW/day) or high doses (100 mg/kg-BW/day) of curcumin dissolved in dimethyl sulfoxide (DMSO) were injected intraperitoneally in all animals for 28 days to investigate the effect of curcumin alone and the combined effect of curcumin with eTR. Western blotting (WB) and immunoprecipitation (IP) were performed to detect the presence of proteins.

RESULTS

Our results demonstrated that combination of curcumin treatment and eTR increased the expression of COX-IV, OXPHOS subunits, mitochondrial DNA copy number and CS activity in the gastrocnemius (Gas) and soleus (Sol) muscles. In addition, this combination increased AMPK phosphorylation, NAD(+)/NADH ratio, SIRT1 expression, and PGC-1α deacetylation. Furthermore, curcumin treatment as well as exercise also increased levels of cAMP and downstream target of PKA including phosphorylation CREB and LKB-1 which are involved in the regulation of mitochondrial biogenesis.

CONCLUSION

Taken together, these results suggest that the combination of curcumin treatment and eTR has the potential to accelerate mitochondrial biogenesis in skeletal muscle by increasing cAMP levels.

Deletion of nuclear factor-κB p50 upregulates fatty acid utilization and contributes to an anti-obesity and high-endurance phenotype in mice

The transcription factor nuclear factor-κB (NF-κB) plays an important role in regulating physiological processes such as immunity and inflammation. In addition to this primary role, NF-κB interacts physically with peroxisome proliferator-activated receptors regulating lipid metabolism-related gene expression and inhibits their transcriptional activity. Therefore, inhibition of NF-κB may promote fatty acid utilization, which could ameliorate obesity and improve endurance capacity. To test this hypothesis, we attempted to elucidate the energy metabolic status of mice lacking the p50 subunit of NF-κB (p50 KO mice) from the tissue to whole body level. p50 KO mice showed a significantly lower respiratory quotient throughout the day than did wild-type (WT) mice; this decrease was associated with increased fatty acid oxidation activity in liver and gastrocnemius muscle of p50 KO mice. p50 KO mice that were fed a high-fat diet were also resistant to fat accumulation and adipose tissue inflammation. Furthermore, p50 KO mice showed a significantly longer maximum running time compared with WT mice, with a lower respiratory exchange ratio during exercise as well as higher residual muscle glycogen content and lower blood lactate levels after exercise. These results suggest that p50 deletion facilitates fatty acid catabolism, leading to an anti-obesity and high-endurance phenotype of mice and supporting the idea that NF-κB is an important regulator of energy metabolism.