AGT M235T and ACE ID polymorphisms and exercise blood pressure in the HERITAGE Family Study

Association between basketball playing position and ACTN3 R577X polymorphism in athletes of first division Brazilian Basketball League

INTRODUCTION

Genetic-association studies have shown that some polymorphisms are associated with different aspects of athletic performance, including very specific features, such as players' position in team sports, like soccer, rugby, and Australian football. However, this type of association has not been investigated in Basketball yet. The present study analyzed the association of ACTN3 R577X, AGT M268T, ACE I/D and BDKRB2+9/-9 polymorphisms with the position of basketball players.

METHODS

One hundred fifty-two male athletes from 11 teams of the first division of Brazilian Basketball League and 154 male Brazilian controls were genotyped. The analyses of the ACTN3 R577X and AGT M268T were performed by the allelic discrimination method, while ACE I/D and BDKRB2+9/-9 by conventional PCR followed by electrophorese in agarose gel.

RESULTS

The results showed a significant effect of height on all positions and an association between the genetic polymorphisms analyzed and basketball positions. In addition, a significantly higher frequency of ACTN3 577XX genotype was observed in Point Guards. Also, compared to Point Guard, ACTN3 RR and RX were more prevalent in the Shooting Guard and Small Forward group and RR genotype was also more prevalent in the Power Forward and Center group.

CONCLUSION

The main finding of our study was the positive association of ACTN3 R577X polymorphism and basketball playing position, and a suggestion of genotypes related to strength/power performance with post players and genotypes related to endurance performance with point guard players.

The HERITAGE Family Study: A Review of the Effects of Exercise Training on Cardiometabolic Health, with Insights into Molecular Transducers

The aim of the HERITAGE Family Study was to investigate individual differences in response to a standardized endurance exercise program, the role of familial aggregation, and the genetics of response levels of cardiorespiratory fitness and cardiovascular disease and diabetes risk factors. Here we summarize the findings and their potential implications for cardiometabolic health and cardiorespiratory fitness. It begins with overviews of background and planning, recruitment, testing and exercise program protocol, quality control measures, and other relevant organizational issues. A summary of findings is then provided on cardiorespiratory fitness, exercise hemodynamics, insulin and glucose metabolism, lipid and lipoprotein profiles, adiposity and abdominal visceral fat, blood levels of steroids and other hormones, markers of oxidative stress, skeletal muscle morphology and metabolic indicators, and resting metabolic rate. These summaries document the extent of the individual differences in response to a standardized and fully monitored endurance exercise program and document the importance of familial aggregation and heritability level for exercise response traits. Findings from genomic markers, muscle gene expression studies, and proteomic and metabolomics explorations are reviewed, along with lessons learned from a bioinformatics-driven analysis pipeline. The new opportunities being pursued in integrative -omics and physiology have extended considerably the expected life of HERITAGE and are being discussed in relation to the original conceptual model of the study.

Influence of Angiotensin Converting Enzyme I/D Polymorphism on Hemodynamic and Antioxidant Response to Long-Term Intradialytic Resistance Training in Patients With Chronic Kidney Disease: A Randomized Controlled Trial

ABSTRACT

Corrêa, HdL, Deus, LA, Neves, RVP, Reis, AL, de Freitas, GS, de Araújo, TB, da Silva Barbosa, JM, Prestes, J, Simões, HG, Amorim, CE, dos Santos, MAP, Haro, A, de Melo, GF, Gadelha, AB, Neto, LS, and Rosa, TdS. Influence of angiotensin converting enzyme I/D polymorphism on hemodynamic and antioxidant response to long-term intradialytic resistance training in patients with chronic kidney disease: a randomized controlled trial. J Strength Cond Res 35(10): 2902-2909, 2021-The aim of the study was to verify the influence of Angiotensin-converting enzyme (ACE) I/D genotype on blood pressure, muscle mass, and redox balance response to long-term resistance training (RT) in end-stage renal disease patients. Three hundred and twenty subjects were randomized into 4 groups: II + ID control (II + ID CTL, n = 80), II + ID RT (II + ID RT, n = 79), DD control (DD CTL n = 83), and DD RT (DD RT, n = 78). The RT lasted 24 weeks with a frequency of 3 times per week, on alternative days. Each section consisted of 3 sets of 8-12 repetitions in 11 exercises, with training loads at 6 point (somewhat hard) to 8 point (hard) based on OMNI-RES scale and was prescribed during dialysis (intradialytic). Statistical significance was accepted with p < 0.05. The most relevant benefits in blood pressure were found for DD homozygotes (p < 0.0001), whereas allele I carriers displayed a higher increase in muscle mass (p < 0.0001). Hemodialysis clinics that already use RT for their patients could include the genotyping of ACE to identify the predisposal of the patients to respond to RT and to counteract kidney disease-related comorbidities.

Mapping Robust Genetic Variants Associated with Exercise Responses

This review summarised robust and consistent genetic variants associated with aerobic-related and resistance-related phenotypes. In total we highlight 12 SNPs and 7 SNPs that are robustly associated with variance in aerobic-related and resistance-related phenotypes respectively. To date, there is very little literature ascribed to understanding the interplay between genes and environmental factors and the development of physiological traits. We discuss future directions, including large-scale exercise studies to elucidate the functional relevance of the discovered genomic markers. This approach will allow more rigour and reproducible research in the field of exercise genomics.

A Systematically Assembled Signature of Genes to be Deep-Sequenced for Their Associations with the Blood Pressure Response to Exercise

: Background: Exercise is one of the best nonpharmacologic therapies to treat hypertension. The blood pressure (BP) response to exercise is heritable. Yet, the genetic basis for the antihypertensive effects of exercise remains elusive. Methods: To assemble a prioritized gene signature, we performed a systematic review with a series of Boolean searches in PubMed (including Medline) from earliest coverage. The inclusion criteria were human genes in major BP regulatory pathways reported to be associated with: (1) the BP response to exercise; (2) hypertension in genome-wide association studies (GWAS); (3) the BP response to pharmacotherapy; (4a) physical activity and/or obesity in GWAS; and (4b) BP, physical activity, and/or obesity in non-GWAS. Included GWAS reports disclosed the statistically significant thresholds used for multiple testing. Results: The search yielded 1422 reports. Of these, 57 trials qualified from which we extracted 11 genes under criteria 1, 18 genes under criteria 2, 28 genes under criteria 3, 27 genes under criteria 4a, and 29 genes under criteria 4b. We also included 41 genes identified from our previous work. Conclusions: Deep-sequencing the exons of this systematically assembled signature of genes represents a cost and time efficient approach to investigate the genomic basis for the antihypertensive effects of exercise.

The influence of angiotensin I-converting enzyme (ACE) I/D gene polymorphism on cardiovascular and muscular adaptations following 8 weeks of isometric handgrip training (IHG) in untrained normotensive males

We examined the association between the angiotensin I-converting enzyme (ACE) I/D gene polymorphism and isometric handgrip (IHG) training on cardiovascular and muscular responses among normotensive males. Thirty (II = 10, ID = 10, and DD = 10) normotensive untrained males underwent IHG training at 30% of their maximal voluntary contraction 3 days per week for 8 weeks. Cardiovascular and muscular variables were measured before IHG, after a session of IHG and after 8 weeks of IHG. No significant interaction effect was found between ACE I/D genotype and IHG training session on all dependent variables (all p > 0.05). There was a significant main effect of IHG training session on systolic blood pressure (SBP) (p = 0.002), mean arterial pressure (MAP) (p = 0.015) and handgrip strength (HGS) (p = 0.001) scores, while no difference in diastolic blood pressure (DBP), pulse pressure, or heart rate scores was found. A greater improvement in cardiovascular parameters following 8 weeks of IHG training was observed in participants with the D allele than the I allele (SBP reduction: ID+DD genotype group (-5.53 ± 6.2 mmHg) vs. II genotype group (-1.52 ± 5.3 mmHg)); MAP reduction: ID + DD genotype group (-2.80 ± 4.5 mmHg) vs. II genotype group (-1.45 ± 3.5 mmHg). Eight weeks of IHG training improved cardiovascular and muscular performances of normotensive men. Reduction in SBP and MAP scores in D allele carriers compared to I allele carriers indicates that the ACE I/D polymorphism may have an influence on IHG training adaptation in a normotensive population.

Deep-targeted sequencing of endothelial nitric oxide synthase gene exons uncovers exercise intensity and ethnicity-dependent associations with post-exercise hypotension

In previous studies, we found an endothelial nitric oxide synthase gene (NOS3) variant rs2070744 associated with the ambulatory blood pressure (BP) response following bouts of moderate and vigorous intensity acute exercise, termed post-exercise hypotension (PEH). In a validation cohort, we sequenced NOS3 exons for associations with PEH Obese (30.9 ± 3.6 kg.m-2) African American (n = 14) [AF] and Caucasian (n = 9) adults 42.0 ± 9.8 years with hypertension (139.8 ± 10.4/84.6 ± 6.2 mmHg) performed three random experiments: bouts of vigorous and moderate intensity cycling and control. Subjects were attached to an ambulatory BP monitor for 19 h. We performed deep-targeted exon sequencing with the Illumina TruSeq Custom Amplicon kit. Variant genotypes were coded as number of minor alleles (#MA) and selected for additional statistical analysis based upon Bonferonni or Benjamini-Yekutieli multiple testing-corrected P-values under time-adjusted linear models for 19 hourly BP measurements for each subject. After vigorous intensity over 19 h, among NOS3 variants passing multiple testing thresholds, as the #MA increased in rs891512 (P = 6.4E-04), rs867225 (P = 6.5E-04), rs743507 (P = 2.6E-06), and rs41483644 (P = 2.4E-04), systolic (SBP) decreased from 17.5 to 33.7 mmHg; and in rs891512 (P = 9.7E-05), rs867225 (P = 2.6E-05), rs41483644 (P = 1.6E-03), rs3730009 (P = 2.6E-04), and rs77325852 (P = 5.6E-04), diastolic BP decreased from 11.1 mmHg to 20.3 mmHg among AF only. In contrast, after moderate intensity over 19 h in NOS3 rs3918164, as the #MA increased, SBP increased by 16.6 mmHg (P = 2.4E-04) among AF only. NOS3 variants exhibited associations with PEH after vigorous, but not moderate intensity exercise among AF only. NOS3 should be studied further for its effects on PEH in a large, ethnically diverse sample of adults with hypertension to confirm our findings.

The angiotensin-converting enzyme insertion/deletion polymorphism rs4340 associates with habitual physical activity among European American adults

BACKGROUND

The angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism (rs4340) (ACE DIP) accounts for half of the variability in plasma ACE concentrations. ACE has been widely studied for its influence on sports performance; however, research on its influence in physical activity is limited and inconsistent. We examined the influence of the ACE DIP on physical activity among 461 European Americans.

METHODS

Subjects completed the Paffenbarger Physical Activity Questionnaire for weekly walking distance. Multivariate analysis of covariance (MANCOVA) tested log-transformed differences in weekly walking distance among ACE DIP genotypes (II, ID, DD) with gender as a fixed factor, and age and body mass index (BMI) as covariates. Because we found a significant ACE DIPxBMI interaction (P = 0.03), we categorized the sample by normal weight (NW: BMI<25.0 kg/m²) and overweight (OW: BMI ≥25.0 kg/m²) and repeated the MANCOVA with multiple comparison adjustments.

RESULTS

NW adults with ACE II walked 15.8 ± 11.1 km/week, ID 13.2 ± 10.6 km/week, and DD 17.9 ± 13.0 km/week, with ID walking less than II (P = 0.03) and DD (P = 0.01). OW adults with ACE II walked 16.7 ± 12.6 km/week, ID 13.8 ± 11.6 km/week, and DD 9.7 ± 9.0 km/week, with DD walking less than II (P = 0.02). Weekly walking distance was 8.2 ± 2.4 km/week less among OW adults with ACE DD than NW (P = 0.02).

CONCLUSION

BMI interacted with ACE DD such that OW walked ~8.2 km/week less than NW, potentially equating to a body weight differential of ~3.5 kg annually.

Deep-targeted exon sequencing reveals renal polymorphisms associate with postexercise hypotension among African Americans

We found variants from the Angiotensinogen-Converting Enzyme (ACE), Angiotensin Type 1 Receptor (AGTR1), Aldosterone Synthase (CYP11B2), and Adducin (ADD1) genes exhibited intensity-dependent associations with the ambulatory blood pressure (BP) response following acute exercise, or postexercise hypotension (PEH). In a validation cohort, we sequenced exons from these genes for their associations with PEH Obese (30.9 ± 3.6 kg m-2) adults (n = 23; 61% African Americans [AF], 39% Caucasian) 42.0 ± 9.8 years with hypertension (139.8 ± 10.4/84.6 ± 6.2 mmHg) completed three random experiments: bouts of vigorous and moderate intensity cycling and control. Subjects wore an ambulatory BP monitor for 19 h. We performed deep-targeted exon sequencing using the Illumina TruSeq Custom Amplicon kit. Variant genotypes were coded as number of minor alleles (#MA) and selected for further statistical analysis based upon Bonferonni or Benjamini-Yekutieli multiple testing corrected p-values under time adjusted linear models for 19 hourly BP measurements per subject. After vigorous intensity over 19 h among ACE, AGTR1, CYP11B2, and ADD1 variants passing multiple testing thresholds, as the #MA increased, systolic (SBP) and/or diastolic BP decreased 12 mmHg (P = 4.5E-05) to 30 mmHg (P = 6.4E-04) among AF only. In contrast, after moderate intensity over 19 h among ACE and CYP11B2 variants passing multiple testing thresholds, as the #MA increased, SBP increased 21 mmHg (P = 8.0E-04) to 22 mmHg (P = 8.2E-04) among AF only. In this replication study, ACE, AGTR1, CYP11B2, and ADD1 variants exhibited associations with PEH after vigorous, but not moderate intensity exercise among AF only. Renal variants should be explored further with a multi-level "omics" approach for associations with PEH among a large, ethnically diverse sample of adults with hypertension.

Structure and functions of angiotensinogen

Angiotensinogen (AGT) is the sole precursor of all angiotensin peptides. Although AGT is generally considered as a passive substrate of the renin-angiotensin system, there is accumulating evidence that the regulation and functions of AGT are intricate. Understanding the diversity of AGT properties has been enhanced by protein structural analysis and animal studies. In addition to whole-body genetic deletion, AGT can be regulated in vivo by cell-specific procedures, adeno-associated viral approaches and antisense oligonucleotides. Indeed, the availability of these multiple manipulations of AGT in vivo has provided new insights into the multifaceted roles of AGT. In this review, the combination of structural and functional studies is highlighted to focus on the increasing recognition that AGT exerts effects beyond being a sole provider of angiotensin peptides.

The blood pressure response to acute and chronic aerobic exercise: A meta-analysis of candidate gene association studies

OBJECTIVES

To meta-analyze candidate gene association studies on the change in blood pressure beyond the immediate post-exercise phase after versus before aerobic exercise.

DESIGN

Meta-analysis.

METHODS

A systematic search was conducted. Studies retrieved included acute (short-term or postexercise hypotension) or chronic (long-term or training) aerobic exercise interventions; and blood pressure measured before and after aerobic exercise training, or before and after exercise or control under ambulatory conditions by genotype. Effect sizes were determined for genotype and adjusted for sample features.

RESULTS

Qualifying studies (k=17, n=3524) on average included middle-aged, overweight men (44.2%) and women (55.8%) with prehypertension (134.9±11.7/78.6±9.5mmHg). Training interventions (k=12) were performed at 60.4±12.9% of maximum oxygen consumption (VO2max) for 41.9±12.5minsession(-1), 3.6±1.2daysweek(-1) for 15.7±7.6week; and post-exercise hypotension interventions (k=5) were performed at 53.5±14.4% VO2max for 38.5±5.4minsession(-1). Sample characteristics explained 54.2-59.0% of the variability in the blood pressure change after versus before acute exercise or control under ambulatory conditions, and 57.4-67.1% of the variability in the blood pressure change after versus before training (p<0.001). Only angiotensinogen M235T (rs699) associated with the change in diastolic blood pressure after versus before training (R(2)=0.1%, p=0.05), but this association did not remain statistically significant after adjustment for multiple comparisons.

CONCLUSIONS

Sample characteristics explained most of the variability in the change of BP beyond the immediate post-exercise phase after versus before acute and chronic aerobic exercise. Angiotensinogen M235T (rs699) was the only genetic variant that associated with the change in diastolic blood pressure after versus before training, accounting for <1% of the variance.

Genomics and genetics in the biology of adaptation to exercise

This article is devoted to the role of genetic variation and gene-exercise interactions in the biology of adaptation to exercise. There is evidence from genetic epidemiology research that DNA sequence differences contribute to human variation in physical activity level, cardiorespiratory fitness in the untrained state, cardiovascular and metabolic response to acute exercise, and responsiveness to regular exercise. Methodological and technological advances have made it possible to undertake the molecular dissection of the genetic component of complex, multifactorial traits, such as those of interest to exercise biology, in terms of tissue expression profile, genes, and allelic variants. The evidence from animal models and human studies is considered. Data on candidate genes, genome-wide linkage results, genome-wide association findings, expression arrays, and combinations of these approaches are reviewed. Combining transcriptomic and genomic technologies has been shown to be more powerful as evidenced by the development of a recent molecular predictor of the ability to increase VO2max with exercise training. For exercise as a behavior and physiological fitness as a state to be major players in public health policies will require that the role of human individuality and the influence of DNA sequence differences be understood. Likewise, progress in the use of exercise in therapeutic medicine will depend to a large extent on our ability to identify the favorable responders for given physiological properties to a given exercise regimen.

Vasopressin: a novel target for the prevention and retardation of kidney disease?

After several decades during which little attention was paid to vasopressin and/or urine concentration in clinical practice, interest in vasopressin has renewed with the availability of new, potent, orally active vasopressin-receptor antagonists--the vaptans--and with the results of epidemiological studies evaluating copeptin (a surrogate marker of vasopressin) in large population-based cohorts. Several experimental studies in rats and mice had previously shown that vasopressin, acting via vasopressin V2 antidiuretic receptors, contributes to the progression of chronic kidney disease; in particular, to autosomal dominant polycystic kidney disease. New epidemiological studies now suggest a role for vasopressin in the pathogenesis of diabetes mellitus and metabolic disorders via activation of hepatic V1a and/or pancreatic islet V1b receptors. The first part of this Review describes the adverse effects of vasopressin, as revealed by clinical and experimental studies in kidney diseases, hypertension, diabetes and the metabolic syndrome. The second part provides insights into vasopressin physiology and pathophysiology that may be relevant to the understanding of these adverse effects and that are linked to the excretion of concentrated nitrogen wastes and associated hyperfiltration. Collectively, the studies reviewed here suggest that more attention should be given to the vasopressin-thirst-urine concentration axis in clinical investigations and in patient care. Whether selective blockade of the different vasopressin receptors may provide therapeutic benefits beyond their present indication in hyponatraemia requires new clinical trials.

Do genetic variations alter the effects of exercise training on cardiovascular disease and can we identify the candidate variants now or in the future?

Cardiovascular disease (CVD) and CVD risk factors are highly heritable, and numerous lines of evidence indicate they have a strong genetic basis. While there is nothing known about the interactive effects of genetics and exercise training on CVD itself, there is at least some literature addressing their interactive effect on CVD risk factors. There is some evidence indicating that CVD risk factor responses to exercise training are also heritable and, thus, may have a genetic basis. While roughly 100 studies have reported significant effects of genetic variants on CVD risk factor responses to exercise training, no definitive conclusions can be generated at the present time, because of the lack of consistent and replicated results and the small sample sizes evident in most studies. There is some evidence supporting “possible” candidate genes that may affect these responses to exercise training: APO E and CETP for plasma lipoprotein-lipid profiles; eNOS, ACE, EDN1, and GNB3 for blood pressure; PPARG for type 2 diabetes phenotypes; and FTO and BAR genes for obesity-related phenotypes. However, while genotyping technologies and statistical methods are advancing rapidly, the primary limitation in this field is the need to generate what in terms of exercise intervention studies would be almost incomprehensible sample sizes. Most recent diabetes, obesity, and blood pressure genetic studies have utilized populations of 10,000–250,000 subjects, which result in the necessary statistical power to detect the magnitude of effects that would probably be expected for the impact of an individual gene on CVD risk factor responses to exercise training. Thus at this time it is difficult to see how this field will advance in the future to the point where robust, consistent, and replicated data are available to address these issues. However, the results of recent large-scale genomewide association studies for baseline CVD risk factors may drive future hypothesis-driven exercise training intervention studies in smaller populations addressing the impact of specific genetic variants on well-defined physiological phenotypes.

Interactions of genetic variants with physical activity are associated with blood pressure in Chinese: the GenSalt study

BACKGROUND

Blood pressure (BP) homeostasis involves complex interactions among genetic and nongenetic factors, providing major challenges to dissection of the genetic components that influence BP and hypertension. In this study, we examine the effects of interaction of genetic variants with physical activity on BP in a relatively genetically homogenous cohort of rural Chinese villagers.

METHODS

Generalized estimating equations analysis was used to test for associations of systolic blood pressure (SBP) and diastolic blood pressure (DBP) with variants in 24 genes in BP pathways (196 single-nucleotide polymorphisms (SNPs)) among 3,142 Chinese participants divided according to physical activity (active vs. inactive groups).

RESULTS

In the physically active group, two SNPs in NR3C2 were significantly associated with lower SBP, and a SNP in SCNN1B was significantly associated with lower SBP and DBP. In the physically inactive group, a SNP in APLNR was associated with lower SBP, a SNP in GNB3 (guanine nucleotide binding protein, β polypeptide 3) was associated with higher SBP and DBP, and a SNP in BDKRB2 (bradykinin receptor B2) was associated with lower DBP. Cumulative effects in carriers of minor alleles of these SNPs showed reductions of SBP and DBP as large as 8 and 5 mm Hg, respectively, in the active individuals compared to inactive individuals carrying the same number of minor alleles.

CONCLUSIONS

We found that physical activity modifies the effects of genetic variants on BP. However, our results also show that active individuals with specific genotypes always have lower BP than inactive individuals with the same genotypes, demonstrating the overall beneficial effects of physical activity on BP.

SNP-by-fitness and SNP-by-BMI interactions from seven candidate genes and incident hypertension after 20 years of follow-up: the CARDIA Fitness Study

The association of SNPs from seven candidate genes, including genotype-by-baseline fitness and genotype-by-baseline body mass index (BMI) interactions, with incident hypertension over 20 years was investigated in 2663 participants (1301 blacks, 1362 whites) of the Coronary Artery Risk Development in Young Adults Study (CARDIA) Study. Baseline cardiorespiratory fitness was determined from duration of a modified Balke treadmill test. A total of 98 SNPs in blacks and 89 SNPs in whites from seven candidate genes were genotyped. Participants that became hypertensive (295 blacks and 146 whites) had significantly higher blood pressure and BMI (both races), and lower fitness (blacks only) at baseline than those who remained normotensive. Markers at the PPARGC1A and BDKRB2 genes were nominally associated with greater risk of hypertension, while one marker each at the BDKRB2 and NOS3 genes were nominally associated with lower risk. The association of baseline fitness with risk of hypertension was nominally modified by genotype at markers within the ACE, AGT, BDKRB2, and NOS3 genes in blacks and the BDKRB2, EDN1, and PPARGC1A genes in whites. BDKRB2 rs4900318 showed nominal interactions with baseline fitness on the risk of hypertension in both races. The association of baseline BMI with risk of hypertension was nominally modified by GNB3 rs2301339 genotype in whites. None of the above associations were statistically significant after correcting for multiple testing. We found that SNPs in these candidate genes did not modify the association between baseline fitness or BMI and risk of hypertension in CARDIA participants.

Impact of genomic polymorphism on arterial hypertension after aortic coarctation repair

OBJECTIVE

Even after repair of aortic coarctation without restenosis there is a high incidence of arterial hypertension. This study was performed to assess the contribution of several inherited gene polymorphisms, which are known to be related to essential hypertension.

PATIENTS AND METHODS

122 patients aged 17-72 years, 46 women, and 2-27 years after repair of isolated aortic coarctation without restenosis were investigated. Genomic polymorphism of angiotensin converting enzyme (ACE I/D), angiotensinogen (AGT, c.704C>T), angiotensin II receptor type 1 (AGTR1, c.1166A>C), aldosterone synthase (CYP11B2, c.-344C>T), endothelin 1 (EDN1, EDN1/ex5-c.5665G>T), G protein (GNB3, c.825C>T), G protein-coupled receptor kinase 4 (GRK4, c.679C>T), fibrillin 1 (FBN1, VNTR(TAAA)) and two polymorphisms each of the ß1 adrenoreceptor (ADRB1, c.145G>A and c.1165C>G), ß2 adrenoreceptor (ADRB2, c.46A>G and c.79C>G), and endothelial NO synthase (NOS3, intron 4 I/D and NOS3, c.894G>T) were determined by PCR amplification and fragment length analysis. Patients were classified "normotensive", if they were not on antihypertensive drugs and showed normal blood pressure both on ambulatory measurement and exercise test.

RESULTS

None of the investigated genomic polymorphism could be related to hypertension. Only patients with the ACE I/I genotype had a less pronounced nocturnal dipping and patients with a ADRB1 c.1165 C/C genotype had a higher systolic and mean blood pressure at night.

CONCLUSIONS

Development of late hypertension after aortic coarctation repair could not be related to the investigated genomic polymorphism. The correlation of the ACE I/D and the ADRB1 c.1165C>G polymorphism to nocturnal dipping and blood pressure at nighttime needs further confirmation.

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.

Gene-physical activity interactions: overview of human studies

Physical activity level is an important component of the total daily energy expenditure and as such contributes to body weight regulation. A body of data indicates that the level of physical activity plays a role in the risk of excessive weight gain, in weight loss programs, and particularly in the prevention of weight regain. Most studies dealing with potential gene-physical activity interaction effects use an exercise and fitness or performance paradigm as opposed to an obesity-driven model. From these studies, it is clear that there are considerable individual differences in the response to an exercise regimen and that there is a substantial familial aggregation component to the observed heterogeneity. Few studies have focused on the role of specific genes in accounting for the highly prevalent gene-exercise interaction effects. Results for specific genes have been inconsistent with few exceptions. Progress is likely to come when studies will be designed to truly address gene-exercise or physical activity interaction issues and with sample sizes that will provide adequate statistical power.

Identifying genes for primary hypertension: methodological limitations and gene-environment interactions

Hypertension segregates within families, indicating that genetic factors explain some of the variance in the risk of developing the disease; however, even with major advances in genotyping technologies facilitating the discovery of multiple genetic risk markers for cardiovascular and metabolic diseases, little progress has been made in defining the genetic defects that cause elevations in blood pressure. Several plausible explanations exist for this apparent paradox, one of which is that the risk conveyed by genes involved in the development of hypertension is context dependent. This notion is supported by a growing number of published animal and human studies, although none has yet provided unequivocal evidence that genetic and environmental factors interact to influence the risk of primary hypertension in humans. In this review, an assumption is made that common genetic variation contributes meaningfully to the development of primary hypertension. The review focuses on (i) several methodological limitations of genetic association studies and (ii) the roles that gene-environment interactions might play in the development of primary hypertension. The proceeding sections of the review examine the design features necessary for future studies to adequately test the hypothesis that genes for primary hypertension act in a context-dependent manner. Finally, an outline of how knowledge of gene-environment interactions might be used to optimize the prevention or treatment of primary hypertension is provided.

A comparison of the genetic and clinical profile of men that respond and do not respond to the immediate antihypertensive effects of aerobic exercise

We compared the genetic and clinical profile of men who lower and do not lower blood pressure (BP) after acute aerobic exercise. Volunteers were 45 men (Mean ± SEM, 43.5 ± 1.5 yr) with high BP (145.7 ± 1.5/85.7 ± 1.1 mmHg). They completed three experiments: nonexercise control and two cycle exercise sessions at 40% and 60% peak oxygen consumption, and were then instrumented to an ambulatory BP monitor. Logistic regression determined the genetic and clinical profile of men who lowered BP after exercise (responders [ExR n = 36]); and those who did not (nonresponders [ExNR n = 9]). ExR had higher C-reactive protein (CRP), high-density lipoprotein (HDL), the metabolic syndrome, family history of hypertension, more renin-angiotensin system (RAS) common alleles, and α-adducin Trp(460) and endothelial nitric oxide synthase (ENOS) C(786) risk alleles. ExNR had lower CRP and HDL, did not have the metabolic syndrome and a family history of hypertension, had more RAS risk alleles, and had the α-adducin Gly460Gly and ENOS T786T genotypes. This model had a sensitivity of 97.1%, specificity of 75.0%, and accounted for 46.3%-74.4% of the BP response. These results suggest genetic and clinical information may eventually be used to characterize people who do and do not respond to exercise as antihypertensive therapy.

Ten renin-angiotensin system-related gene polymorphisms in maximally treated Canadian Caucasian patients with heart failure

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

The progression and pharmacological response of heart failure-affected patients are subject to interindividual variability. It is also acknowledged that the genotype frequency of certain gene polymorphisms varies across different ethnic groups and that a difference in gene polymorphism frequencies between healthy and heart failure patients seems to exist.

WHAT THIS STUDY ADDS

This study investigated associations between 10 gene polymorphisms of RAAS-related genes with an individual's susceptibility to heart failure. Our data suggest that the angiotensinogen (AGT) 235 single nucleotide polymorphism (SNP) may be associated with heart failure in our population and that the AGT(M174)-AGT(T235) haplotype, as well as the AGT/angiotensin-converting enzyme (ACE) gene combination, may play an important role in disease predisposition.

AIMS

Racial differences in survival outcomes point towards a genetic role in the pathophysiology of heart failure. Furthermore, contemporary evidence links genetics to heart failure (HF) predisposition. We tested for a difference in prevalence of 10 renin-angiotensin-aldosterone system (RAAS)-related gene polymorphisms between a homogenous population of HF patients and healthy controls.

METHODS

One hundred and eleven healthy volunteers and 58 HF patients were included in this study. The healthy control group consisted of males aged between 18 and 35 years old. The HF group consisted of patients (89.7% male) who were 63.8 +/- 7.9 years old, were in New York Heart Association (NYHA) class II-III and had a documented left ventricular ejection fraction (LVEF)

CONCLUSIONS

This study demonstrates that the SNPs of AGT may be associated with HF in our population and that the AGT/ACE gene combination may play an important role in disease predisposition.

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Key Words

• ace
• angiotensin
• heart failure
• polymorphisms
• raas
• renin

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MESH Headings

• Adolescent
• Adult
• Aged
• Canada/epidemiology
• Double-Blind Method
• Female
• Gene Frequency/genetics
• Genetic Predisposition to Disease/genetics
• Heart Failure/blood
• Heart Failure/genetics
• Humans
• Male
• Middle Aged
• Polymorphism, Genetic
• Renin-Angiotensin System/genetics
• White People/genetics

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Affiliation(s)

Marcin Zakrzewski-Jakubiak Université de MontréalMontréal, Canada
Simon de Denus Université de MontréalMontréal, Canada Montreal Heart InstituteMontréal, Canada
Marie-Pierre Dubé Montreal Heart InstituteMontréal, Canada
François Bélanger Université de MontréalMontréal, Canada
Michel White Montreal Heart InstituteMontréal, Canada
Jacques Turgeon Université de MontréalMontréal, Canada

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Cardiorespiratory fitness, BMI, and risk of hypertension: the HYPGENE study

INTRODUCTION

Cardiorespiratory fitness and regular physical activity are inversely associated with the risk of hypertension, and exercise training has been shown to lower elevated blood pressure (BP). Genetic factors contribute significantly to the interindividual differences in endurance training-induced changes in BP. However, similar data on the genotype-by-fitness interactions on the risk of hypertension are scarce.

METHODS

In 2000, we started a systematic collection of blood samples from all consenting subjects of the Aerobics Center Longitudinal Study (ACLS) with a goal to generate a resource for studies addressing genotype-by-fitness interaction effects on various health-related end points. Here, we introduce the rationale and design of the first study based on the ACLS genetics resource focusing on hypertension as the health outcome (HYPGENE study), and we report the associations of cardiorespiratory fitness and body mass index (BMI) with the risk of hypertension. All HYPGENE subjects (N = 1234) were healthy and normotensive at their first clinic visit. Cases (N = 629) developed hypertension during the follow-up period (mean 8.7 yr), whereas controls (N = 605) remained normotensive (mean follow-up 10.1 yr).

RESULTS

Cardiorespiratory fitness was the strongest predictor of the hypertension risk, with each maximal metabolic equivalent unit being associated with a 19% lower risk (95% confidence interval [95% CI], 12-24%). Each baseline BMI unit was associated with a 9% higher hypertension risk (95% CI, 4-13%). However, the association of BMI was greatly attenuated (odds ratio 1.04 [95% CI, 0.99-1.09]) when fitness also was included in the model.

CONCLUSIONS

The HYPGENE study will provide an excellent resource to address hypotheses regarding the genetic basis of hypertension while taking cardiorespiratory fitness level into account.

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.

The effects of exercise on haemodynamic function in relation to the familial hypertension risk model

Offspring hypertensives are characterized by a hyperactive sympathetic nervous system and other early cardiovascular abnormalities that increase the risk of developing hypertension. A physically active lifestyle is associated with a lower risk of hypertension, although the mechanisms are incompletely understood and likely to be multifactorial. One aspect that has received little attention is the interaction of exercise with familial hypertension risk. The present review examines the effects of exercise on haemodynamic function in relation to the familial hypertension risk model. Paradoxically, exercise may be viewed as potent stressor to the cardiovascular system, although recent studies are beginning to show that cardiovascular adaptations, primarily mediated by changes in sympatho-vagal balance, following both acute and chronic exercise may be particularly important for individuals with familial risk of hypertension. Future studies that focus on inflammatory, metabolic, and genetic pathways may uncover further beneficial effects of exercise in relation to familial risk.

RAAS polymorphisms alter the acute blood pressure response to aerobic exercise among men with hypertension

Limited evidence suggests renin-angiotensin-aldosterone system (RAAS) polymorphisms alter the blood pressure (BP) response to aerobic exercise training. We examined if RAAS polymorphisms influenced postexercise hypotension in men with high normal to Stage 1 hypertension. Forty-seven men (44.2+/-1.4 years, 145.1+/-1.6/85.5+/-1.1 mmHg) randomly completed three experiments: seated rest (control) and two cycle exercise bouts at 40% (LITE) and 60% (MOD) of maximal oxygen consumption. Ambulating BP was measured for 14 h after each experiment. RAAS polymorphisms associated with hypertension (i.e. angiotensin converting I enzyme, ACE I/D; angiotensin II type 1 receptor, AT1R A/C; and intron 2 of aldosterone synthase, Int2 W/C) were analyzed using polymerase chain reaction and restriction enzyme digestion. Repeated measure ANOVA tested if BP differed between experimental conditions by RAAS genotypes. Compared to men with 0-2 variant alleles, men with > or =3 combined RAAS variant alleles had lower average systolic BP (SBP) (P=0.030) and lower average diastolic BP (DBP) (P=0.009) for 14 h only after LITE. In contrast, average BP was not different for MOD and control between RAAS variant allele groups over this time period (P> or =0.05). LITE reduced BP in men with > or =3 variant RAAS alleles for 14 h, whereas MOD had no influence on BP in these men. In order to optimally prescribe exercise for its BP lowering benefits in those with hypertension, additional knowledge of how genetic variation affects the BP response to exercise is needed.

Association of angiotensinogen gene polymorphisms with essential hypertension in African-Americans and Caucasians

OBJECTIVE

Molecular variants of angiotensinogen (AGT) have been linked to essential hypertension, and promoter variants have been shown to alter the transcription rate of AGT in vitro. We employed a case-control study to determine whether single nucleotide polymorphisms (SNPs) in the promoter region of AGT were associated with hypertension in African-Americans and Caucasians.

METHODS

The frequencies of the variants at base positions -6, -20, -217, -793, and -776, both alone and in combination (haplotypes), were compared between cases and controls in samples stratified based on race and sex. A logistic regression model was applied to test whether AGT genotypes were significant predictors of the disease while adjusting for race, sex, and age.

RESULTS

Subjects with the AA or AG genotype at locus -793 were significantly more likely to have the disease (OR = 1.88, 95% CI = 1.12-3.15). Additionally, the differences in haplotype frequency distributions between cases and controls were significant at the 7% level for all four subgroups (stratified by race and sex) after adjusting for multiple testing. Based on the odds ratios for each individual haplotype, the haplotype AAAAT (nucleotide sequences at base positions -6, -20, -217, -793, -776) in African-American males, African-American females, and Caucasian females may confer susceptibility to the disease in these population subsets.

CONCLUSION

Overall, the present report provides statistical evidence for the association of AGT with essential hypertension.

Blood pressure response to strength training may be influenced by angiotensinogen A-20C and angiotensin II type I receptor A1166C genotypes in older men and women

OBJECTIVES

To determine the influence of angiotensinogen (AGT) A-20C, M235 T, and angiotensin II type 1 receptor (AGTR1) A1166C genotypes on resting blood pressure (BP) response to strength training (ST) in older men and women.

DESIGN

Prospective intervention study with retrospective genotyping.

SETTING

University of Maryland Exercise Physiology Laboratory.

PARTICIPANTS

Seventy sedentary, healthy older men (n=34) and women (n=36).

INTERVENTION

Approximately 23 weeks of ST performed 3 days per week.

MEASUREMENTS

Resting BP was measured on six separate occasions before and after ST for each subject. AGT and AGTR1 genotyping was performed retrospectively from each subject's genomic deoxyribonucleic acid.

RESULTS

Systolic BP decreased in C-allele carriers at the AGT A-20C locus with ST (122+/-1 to 116+/-2 mmHg, P<.05), which was significantly greater than the decrease in the A homozygotes (126+/-1 to 123+/-1 mmHg, P<.05). At the AGTR1 A1166C locus, diastolic BP decreased to a greater extent in the C-allele carriers (76+/-1 to 70+/-2 mmHg, P<.05) than in the A homozygotes (75+/-1 to 72+/-1 mmHg, P<.05).

CONCLUSION

The AGT A-20C and AGTR1 A1166C genotypes may influence resting BP response to ST, such that C-allele carriers at each of these loci reduce their resting BP in response to ST to a greater extent than A homozygotes.

The human gene map for performance and health-related fitness phenotypes: the 2003 update

This review presents the 2003 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 2003 and includes association studies with candidate genes, genome-wide scans with polymorphic markers, and single-gene defects causing exercise intolerance to variable degrees. 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, 29 loci were depicted on the first edition of the map. In contrast, the 2003 human gene map for physical performance and health-related phenotypes includes 109 autosomal gene entries and QTL, plus two on the X chromosome. Moreover, there are 15 mitochondrial genes in which sequence variants have been shown to influence relevant fitness and performance phenotypes.

Beta2- and beta3-adrenergic receptor polymorphisms and exercise hemodynamics in postmenopausal women

We sought to determine whether common genetic variations at the beta2 (beta2-AR, Gln27Glu) and beta3 (beta3-AR, Trp64Arg) adrenergic receptor gene loci were associated with cardiovascular (CV) hemodynamics during maximal and submaximal exercise. CV hemodynamics were assessed in 62 healthy postmenopausal women (20 sedentary, 22 physically active, and 20 endurance athletes) during treadmill exercise at 40, 60, 80, and 100% maximal O2 uptake using acetylene rebreathing to quantify cardiac output. The beta2-AR genotype and habitual physical activity (PA) levels interacted to significantly associate with arteriovenous O2 difference (a-vDO2) during submaximal exercise (P = 0.05), with the highest submaximal exercise a-vDO2 in sedentary women homozygous for the beta2-AR Gln allele and no genotype-dependent differences in submaximal exercise a-vDO2 in physically active and athletic women. The beta2-AR genotype also was independently associated with a-vDO2 during submaximal (P = 0.004) and approximately 100% maximal O2 uptake exercise (P = 0.006), with a 1.2-2 ml/100 ml greater a-vDO2 in the Gln/Gln than in the Glu/Glu genotype women. The beta3-AR genotype, independently or interacting with habitual PA levels, was not significantly associated with any CV hemodynamic variables during submaximal or maximal exercise. Thus it appears that the beta2-AR genotype, both independently and interacting with habitual PA levels, is significantly associated with a-vDO2 during exercise in postmenopausal women, whereas the beta3-AR genotype does not appear to be associated with any maximal or submaximal exercise CV hemodynamic responses in postmenopausal women.

American College of Sports Medicine position stand. Exercise and hypertension

Hypertension (HTN), one of the most common medical disorders, is associated with an increased incidence of all-cause and cardiovascular disease (CVD) mortality. Lifestyle modifications are advocated for the prevention, treatment, and control of HTN, with exercise being an integral component. Exercise programs that primarily involve endurance activities prevent the development of HTN and lower blood pressure (BP) in adults with normal BP and those with HTN. The BP lowering effects of exercise are most pronounced in people with HTN who engage in endurance exercise with BP decreasing approximately 5-7 mm HG after an isolated exercise session (acute) or following exercise training (chronic). Moreover, BP is reduced for up to 22 h after an endurance exercise bout (e.g.postexercise hypotension), with greatest decreases among those with highest baseline BP. The proposed mechanisms for the BP lowering effects of exercise include neurohumoral, vascular, and structural adaptations. Decreases in catecholamines and total peripheral resistance, improved insulin sensitivity, and alterations in vasodilators and vasoconstrictors are some of the postulated explanations for the antihypertensive effects of exercise. Emerging data suggest genetic links to the BP reductions associated with acute and chronic exercise. Nonetheless, definitive conclusions regarding the mechanisms for the BP reductions following endurance exercise cannot be made at this time. Individuals with controlled HTN and no CVD or renal complications may participated in an exercise program or competitive athletics, but should be evaluated, treated and monitored closely. Preliminary peak or symptom-limited exercise testing may be warranted, especially for men over 45 and women over 55 yr planning a vigorous exercise program (i.e. > or = 60% VO2R, oxygen uptake reserve). In the interim, while formal evaluation and management are taking place, it is reasonable for the majority of patients to begin moderate intensity exercise (40-<60% VO2R) such as walking. When pharmacological therapy is indicated in physically active people it should be, ideally: a) lower BP at rest and during exertion; b) decrease total peripheral resistance; and, c) not adversely affect exercise capacity. For these reasons, angiotensin converting enzyme (ACE) inhibitors (or angiotensin II receptor blockers in case of ACE inhibitor intolerance) and calcium channel blockers are currently the drugs of choice for recreational exercisers and athletes who have HTN. Exercise remains a cornerstone therapy for the primary prevention, treatment, and control of HTN. The optimal training frequency, intensity, time, and type (FITT) need to be better defined to optimize the BP lowering capacities of exercise, particularly in children, women, older adults, and certain ethnic groups. based upon the current evidence, the following exercise prescription is recommended for those with high BP: Frequency: on most, preferably all, days of the week. Intensity: moderate-intensity (40-<60% VO2R). Time: > or = 30 min of continuous or accumulated physical activity per day. Type: primarily endurance physical activity supplemented by resistance exercise.

Physical activity and angiotensin-converting enzyme gene polymorphism in mild hypertensives

It has been suggested that the insertion(I) allele of the I/deletion(D) polymorphism of the angiotensin converting enzyme (ACE) gene is associated with endurance exercise and increased physical conditioning in response to this type of exercise. To investigate the association between the ACE I/D polymorphism and physical activity status in 355 never treated, stage I hypertensives (265 men, 90 women, mean age: 33 +/- 9 years), in whom power exercise is contraindicated, participants of the HARVEST study. Physical activity was assessed using a standardized questionnaire. BMI and age did not vary among genotypes. None of active subjects performed power oriented exercises. ACE I/D frequencies (II-18%, ID-55%, DD-27%) were in Hardy-Weinberg equilibrium. Sedentary lifestyle was more common among DD than II hypertensives (76% in DD, and 48% in II, Chi(2) = 13.9, P = 0.001). In stepwise MANOVA using age, marital status, profession, sex, and ACE genotype as predictors of physical activity, marital status (F = 24.4, P < 0.0001) and ACE genotype (F = 16.03, P < 0.0001) contributed to more than 50% of the variance in physical activity status of the population. Our results suggest that the ACE I/D polymorphism may be a specific genetic factor associated with physical activity levels in free-living borderline and mild hypertensive subjects.

The human gene map for performance and health-related fitness phenotypes: the 2002 update

This review presents the 2002 update of the human gene map for physical performance and health-related phenotypes. It is based on peer-reviewed papers published by the end of 2002 and includes association studies with candidate genes, genome-wide scans with polymorphic markers, and single gene defects causing exercise intolerance to variable degrees. 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, 29 loci were depicted on the map. The 2001 map includes 71 loci on the autosomes and two on the X chromosome. In contrast, the 2002 human gene map for physical performance and health-related phenotypes includes 90 gene entries and QTL, plus two on the X chromosome. To all these loci, one must add 14 mitochondrial genes in which sequence variants have been shown to influence relevant fitness and performance phenotypes.

Relation between the angiotensinogen (AGT) M235T gene polymorphism and blood pressure in a large, homogeneous study population

The aim of this study was to assess the association of the angiotensinogen M235T polymorphism with arterial blood pressure (BP) at rest and under physical stress in a homogeneous large-scale study population. In all, 1903 men who passed routine medical examination for military flying duty were recruited. BP and heart rate were measured at rest, during, and after bicycle ergometry. Genotyping for the AGT M235T polymorphism was carried out by PCR and RFLP technique. The AGT T235 allele was associated with a significantly higher diastolic BP (n=1903; MM 81+/-8, MT 83+/-7, TT 83+/-8; P=0.003). Pulse pressure (PP) at rest differed significantly between AGT genotypes (n=1903; MM 51+/-10 mmHg, MT 49+/-10 mmHg, TT 49+/-10 mmHg; P=0.001). During physical activity, BP values showed no significant difference between genotypes. In healthy young men, the AGT T235 allele is significantly associated with elevated diastolic BP but also reduced PP at rest. During physical activity, the AGT polymorphism had no impact on blood pressure, indicating the existence of other counteracting mechanisms, which might balance the influence of this gene.

Genetics and blood pressure response to exercise, and its interactions with adiposity

Regular aerobic exercise has the potential to induce several beneficial health effects, including a decrease in blood pressure level, especially in hypertensive patients and in subjects with high-normal blood pressure. However, it is also well documented that some people show more pronounced blood pressure responses to endurance training than others, despite identical training programs and similar initial blood pressure levels. This kind of variation is an example of normal biologic diversity and most likely originates from interactions with genetic factors. Data from genetic epidemiologic studies indicate that there is a genetic component that affects both resting blood pressure and blood pressure responses to acute exercise. Evidence from molecular genetic studies is scarce, but the first reports suggest that DNA sequence variation in the hypertension candidate genes, such as angiotensinogen, also modify blood pressure responses to endurance training. The current knowledge regarding the role of genetic factors in the modification of blood pressure responses to endurance training will be summarized and discussed.

Physical exercise and blood pressure with reference to the angiotensinogen M235T polymorphism

We investigated the role of the angiotensinogen (AGT) gene M235T polymorphism in determining blood pressure (BP) response to moderate intensity exercise in a 6-yr randomized controlled trial in 140 middle-aged men. Sitting, supine, and standing blood pressures were measured annually. Of the randomized men, 86% participated in the trial for 6 yr. Submaximal cardiorespiratory fitness increased by 16% in the exercise group. In the M homozygotes, sitting systolic BP decreased by 1.0 mmHg in the exercise but increased by 14.6 mmHg in the reference group (P = 0.007 for net effect). Sitting and supine diastolic BP decreased by 6.2 and 3.3 mmHg in the exercise but increased by 2.8 and 3.2 mmHg in the reference group (P = 0.026 and 0.024 for net effects), respectively. Regular moderate intensity exercise attenuates aging-related increase in systolic BP and decreases diastolic BP among the M homozygotes of the AGT gene M235T polymorphism.

Angiotensinogen M235T polymorphism associates with exercise hemodynamics in postmenopausal women

We sought to determine whether the M235T angiotensinogen (AGT) polymorphism, either interacting with habitual physical activity (PA) levels or independently, was associated with cardiovascular (CV) hemodynamics during maximal and submaximal exercise. Sixty-one healthy postmenopausal women (16 sedentary, 21 physically active, and 24 endurance athletes) had heart rate (HR), blood pressure (BP), cardiac output, stroke volume (SV), total peripheral resistance (TPR), and arteriovenous O2 difference (a-vDO2) assessed during 40, 60, 80, and approximately 100% of VO2 max treadmill exercise. VO2 max did not differ among AGT genotype groups; however, maximal HR was 14 beats/min higher in AGT TT than MM genotype women (P < 0.05). AGT TT genotype women also had 19 beats/min higher HR during approximately 100% VO2 max exercise than AGT MM genotype women (P = 0.008). AGT genotype also interacted with habitual PA levels to associate with systolic BP and a-vDO2 during approximately 100% VO2 max exercise (both P < 0.01). AGT TT genotype women had 11 beats/min higher HR during submaximal exercise than MM genotype women (P < 0.05). AGT genotype interacted with habitual PA levels to associate with systolic BP during submaximal exercise (P = 0.009). AGT genotype, independently or interacting with habitual PA levels, did not associate significantly with diastolic BP, cardiac output, SV, or TPR during maximal or submaximal exercise. Thus this common genetic variant in the renin-angiotensin system appears to associate, both interactively with habitual PA levels and independently, with HR, systolic BP, and a-vDO2 responses to maximal and submaximal exercise in postmenopausal women.

The human gene map for performance and health-related fitness phenotypes: the 2001 update

This review presents the 2001 update of the human gene map for physical performance and health-related phenotypes. It is based on scientific papers published by the end of 2001. Association studies with candidate genes, genome-wide scans with polymorphic markers, and single gene defects causing exercise intolerance to variable degrees are included. 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, there were 29 loci depicted on the map. The 2001 map includes 71 loci on the autosomes and two on the X chromosome. Among these genes or markers, 24 are from prior publications on exercise intolerance and four relate to other pathologies. Finally, 13 sequence variants in mitochondrial DNA have been shown to influence relevant fitness and performance phenotypes.

Sympathetic activity and the heterogenous blood pressure response to exercise training in hypertensives

To test whether changes in sympathetic nervous system (SNS) activity or insulin sensitivity contribute to the heterogeneous blood pressure response to aerobic exercise training, we used compartmental analysis of [3H]norepinephrine kinetics to determine the extravascular norepinephrine release rate (NE2) as an index of systemic SNS activity and determined the insulin sensitivity index (S(I)) by an intravenous glucose tolerance test, before and after 6 mo of aerobic exercise training, in 30 (63 +/- 7 yr) hypertensive subjects. Maximal O2 consumption increased from 18.4 +/- 0.7 to 20.8 +/- 0.7 ml x kg(-1) x min(-1) (P = 0.02). The average mean arterial blood pressure (MABP) did not change (114 +/- 2 vs. 114 +/- 2 mmHg); however, there was a wide range of responses (-19 to +17 mmHg). The average NE2 did not change significantly (2.11 +/- 0.15 vs. 1.99 +/- 0.13 microg x min(-1) x m(-2)), but there was a significant positive linear relationship between the change in NE2 and the change in MABP (r = 0.38, P = 0.04). S(I) increased from 2.81 +/- 0.37 to 3.71 +/- 0.42 microU x 10(-4) x min(-1) x ml(-1) (P = 0.004). The relationship between the change in S(I) and the change in MABP was not statistically significant (r = -0.03, P = 0.89). When the changes in maximal O2 consumption, percent body fat, NE2, and S(I) were considered as predictors of the change in MABP, only NE2 was a significant independent predictor. Thus suppression of SNS activity may play a role in the reduction in MABP and account for a portion of the heterogeneity of the MABP response to aerobic exercise training in older hypertensive subjects.

ACE insertion/deletion polymorphism and submaximal exercise hemodynamics in postmenopausal women

We sought to determine whether the angiotensin-converting enzyme (ACE) insertion (I)/deletion (D) polymorphism is associated with submaximal exercise cardiovascular hemodynamics. Postmenopausal healthy women (20 sedentary, 20 physically active, 22 endurance athletes) had cardiac output (acetylene rebreathing) measured during 40, 60, and 80% VO(2 max) exercise. The interaction of ACE genotype and habitual physical activity (PA) level was significantly associated with submaximal exercise systolic blood pressure, with only sedentary women exhibiting differences among genotypes. No significant effects of ACE genotype or its interaction with PA levels was observed for submaximal exercise diastolic blood pressure. ACE genotype was significantly associated with submaximal exercise heart rate (HR) with ACE II having approximately 10 beats/min higher HR than ACE ID/DD genotype women. ACE genotype did not interact significantly with habitual PA level to associate with submaximal exercise HR. ACE genotype was not independently, but was interactively with habitual PA levels, associated with differences in submaximal exercise cardiac output and stroke volume. For cardiac output, ACE II genotype women athletes had ~25% greater cardiac output than ACE DD genotype women athletes, whereas for stroke volume genotype-dependent differences were observed in both the physically active and athletic women. ACE genotype was not significantly associated, either independently or interactively with habitual PA levels, with submaximal exercise total peripheral resistance or arteriovenous O(2) difference. Thus the common ACE locus polymorphic variation is associated with many submaximal exercise cardiovascular hemodynamic responses.

Nucleotide diversity and haplotype structure of the human angiotensinogen gene in two populations

Variation in the angiotensinogen gene, AGT, has been associated with variation in plasma angiotensinogen levels. In addition, the T235M polymorphism in the AGT product is associated with an increased risk of essential hypertension in multiple populations, making AGT a good example of a quantitative-trait locus underlying susceptibility to a common disease. To better understand genetic variation in AGT, we sequenced a 14.4-kb genomic region spanning the entire AGT and identified 44 single-nucleotide polymorphisms (SNPs). Forty-two SNPs were observed both in 88 white and in 77 Japanese unselected subjects. Six major haplotypes accounted for most of the variation in this region, indicating less allelic complexity than in many other genomic regions. Although the two populations were found to share all of the major AGT haplotypes, there were substantial differences in haplotype frequencies. Pairwise linkage disequilibrium (LD), measured by the D', r(2), and d(2) statistics, demonstrated a general pattern of decline with increasing distance, but, as expected in a small genomic region, individual LD values were highly variable. LD between T235M and each of the other 39 SNPs was assessed in order to model the usefulness of LD to detect a disease-associated mutation. Among the Japanese subjects, 13 (33%) of the SNPs had r(2) values >0.1, whereas this statistic was substantially higher for the white subjects (occurring in 35/39 [90%]). LD between a hypertension-associated promoter mutation, A-6G, and 39 SNPs was also measured. Similar results were obtained, with 33% of the SNPs showing r(2)>0.1 in the Japanese subjects and 92% of the SNPs showing r(2)>0.1 in the white subjects. This difference, which occurs despite an overall similarity in LD patterns in the two populations, reflects a much higher frequency of the M235-associated haplotype in the white sample. These results have important implications for the usefulness of LD approaches in the mapping of genes underlying susceptibility to complex diseases.

A point of view: quantitative and qualitative imbalance in disease pathogenesis; pulmonary surfactant protein A genetic variants as a model

The high degree of similarity at the molecular level, between humans and other species, has provided the rationale for the use of a variety of species as model systems in research, resulting in enormous advances in biological sciences and medicine. In contrast, the individual variability observed among humans, for example, in external physique, organ functionality and others, is accounted for, by only a fraction of 1% of differences at the DNA level. These small differences, which are essential for understanding disease pathogenesis, have posed enormous challenges in medicine, as we try to understand why patients may respond differently to drugs or why one patient has complications and another does not. Differences in outcome are most likely the result of interactions among genetic components themselves and/or the environment at the molecular, cellular, organ, or organismal level, or the macroenvironment. In this paper: (1) we consider some issues for multifactorial disease pathogenesis; (2) we provide a review of human SP-A and how the knowledge gained and the characteristics of the hSP-A system may serve as a model in the study of disease with multifactorial etiology; and (3) we describe examples where hSP-A has been used in the study of disease.

Variations of cardiovascular disease associated genes exhibit sex-dependent influence on human longevity

This article investigates the relationship between the polymorphic variations in genes associated with cardiovascular disease and longevity in the Danish population. A new procedure that combines both demographic and the individual genetic information in determining the relative risks of the observed genetic variations is applied. The sex-dependent influences can be found by introducing sex-specific population survival and incorporating the risk of gene-sex interaction. Three genetic polymorphisms, angiotensinogen M/T235, blood coagulation factor VII (FVII) R/Q353 and FVII-323ins10, manifest significant influences on survival in males, with reduced hazards of death for carriers of the angiotensinogen M235 allele, the F VII Q353 allele, and the FVII-323P10 allele. The results show that some of these genotypes associated with lower risk of CVD could also reduce the carrier's death rate and contribute to longevity. However, the presence of sex-dependent effects and the fact that major CVD-associated genes failed to impose detrimental influence on longevity lead us to concur that the aging process is highly complicated.

The human gene map for performance and health-related fitness phenotypes

The aim of this paper is to describe the first human gene map for physical performance and health-related fitness traits based on the papers published until the end of 2000. Studies of candidate genes using case-control and other designs are reviewed. Quantitative trait loci from the limited evidence reported to date in genomic scans are also incorporated. Performance and fitness phenotypes in the sedentary state as well as their changes during exercise, if applicable, or in response to exercise training are considered. Physical performance traits include cardiorespiratory endurance indicators and muscular strength or muscular performance variables. Health-related fitness phenotypes are grouped under the following categories: hemodynamic traits; anthropometry and body composition; insulin and glucose metabolism; and lipids, lipoproteins, and hemostatic factors. A yearly update of this human gene map will be published.

Clustering of metabolic abnormalities in obese individuals: the role of genetic factors

The objective of this paper is to review the current evidence in support of genetic factors underlying the clustering of components of the metabolic syndrome in obese individuals. It has become clear that individual features of the metabolic syndrome are partially determined by familial factors some of which are unique to a given component and others that are shared among several features. A few candidate genes, encoding proteins of glucose, insulin and lipid metabolism, lipolytic cascade, fatty acid intestinal absorption, glucocorticoid metabolism, haemostasis and blood pressure, have been associated with a clustering of metabolic abnormalities, although the functional significance of these associations remains to be established. Furthermore, genetic polymorphisms, such as those detected at several lipoprotein metabolism loci, can modulate the relationships between different components of the metabolic syndrome. An overfeeding study conducted on identical twins has demonstrated that genetic factors play an important role in the responsiveness to changing energy balance conditions. Leptin receptor, beta2 adrenergic receptor and glucocorticoid receptor gene polymorphisms have been associated with an augmented clustering of metabolic abnormalities in response to overfeeding. Gene-gene interaction effects between markers of the alpha2A, beta2 and beta3 adrenergic receptor genes on components of the metabolic syndrome have been described. Genetic factors also seem to modify the responsiveness of metabolic syndrome features to endurance training. A growing understanding of the genetic architecture of the metabolic syndrome may help in the prevention of this condition. The reduction of excess body fat, the most common clinical feature among the cluster of metabolic abnormalities, should be the focus of the prevention and treatment of the metabolic syndrome.