Exercise-induced changes in insulin action are associated with ACE gene polymorphisms in older adults

Post-translational dysregulation of glucose uptake during exhaustive cycling exercise in vastus lateralis muscle of healthy homozygous carriers of the ACE deletion allele

Homozygous carriers of the deletion allele in the gene for angiotensin-converting enzyme (ACE-DD) demonstrate an elevated risk to develop inactivity-related type II diabetes and show an overshoot of blood glucose concentration with enduring exercise compared to insertion allele carriers. We hypothesized that ACE-DD genotypes exhibit a perturbed activity of signaling processes governing capillary-dependent glucose uptake in vastus lateralis muscle during exhaustive cycling exercise, which is associated with the aerobic fitness state. 27 healthy, male white Caucasian subjects (26.8 ± 1.1 years; BMI 23.6 +/− 0.6 kg m⁻²) were characterized for their aerobic fitness based on a threshold of 50 ml O₂ min⁻¹ kg⁻¹ and the ACE-I/D genotype. Subjects completed a session of exhaustive one-legged exercise in the fasted state under concomitant measurement of cardiorespiratory function. Capillary blood and biopsies were collected before, and ½ and 8 h after exercise to quantify glucose and lipid metabolism-related compounds (lipoproteins, total cholesterol, ketones) in blood, the phosphorylation of 45 signaling proteins, muscle glycogen and capillaries. Effects of aerobic fitness, ACE-I/D genotype, and exercise were assessed with analysis of variance (ANOVA) under the hypothesis of a dominant effect of the insertion allele. Exertion with one-legged exercise manifested in a reduction of glycogen concentration ½ h after exercise (−0.046 mg glycogen mg⁻¹ protein). Blood glucose concentration rose immediately after exercise in association with the ACE-I/D genotype (ACE-DD: +26%, ACE-ID/II: +6%) and independent of the fitness state (p = 0.452). Variability in total cholesterol was associated with exercise and fitness. In fit subjects, the phosphorylation levels of glucose uptake-regulating kinases [AKT-pT308 (+156%), SRC-pY419, p38α-pT180/T182, HCK-pY411], as well as cytokine/angiotensin 1-7 signaling factors [(STAT5A-pY694, STAT5B-pY699, FYN-pY420, EGFR-pY1086] were higher in angiotensin converting enzyme I-allele carriers than ACE-DD genotypes after exercise. Conversely, the AKT-S473 phosphorylation level (+117%) and angiotensin 2’s blood concentration (+191%) were higher in ACE-DD genotypes. AKT-S473 phosphorylation levels post-exercise correlated to anatomical parameters of muscle performance and metabolic parameters (p < 0.05 and │r│>0.70). The observations identify reciprocal alterations of S473 and T308 phosphorylation of AKT as gatekeeper of a post-translational dysregulation of transcapillary glucose uptake in ACE-DD genotypes which may be targeted in personalized approaches to mitigate type II diabetes.

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.

The renin-angiotensin system and prevention of age-related functional decline: where are we now?

Declining physical function is a major health problem for older adults as it is associated with multiple comorbidities and mortality. Exercise has been shown to improve physical function, though response to exercise is variable. Conversely, drugs targeting the renin-angiotensin system (RAS) pathway, including angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARBs), are also reported to improve physical function. In the past decade, significant strides have been made to understand the complexity and specificity of the RAS system as it pertains to physical function in older adults. Prior findings have also determined that interactions between antihypertensive medications and exercise may influence physical function above and beyond either factor alone. We review the latest research on RAS, exercise, and physical function for older adults. We also outline future research aims in this area, including genetic influences and clinical phenotyping, for the purpose of maintaining or improving physical function through tailored treatments.

Neuro-hormonal effects of physical activity in the elderly

Thanks to diagnostic and therapeutic advances, the elderly population is continuously increasing in the western countries. Accordingly, the prevalence of most chronic age-related diseases will increase considerably in the next decades, thus it will be necessary to implement effective preventive measures to face this epidemiological challenge. Among those, physical activity exerts a crucial role, since it has been proven to reduce the risk of cardiovascular diseases, diabetes, obesity, cognitive impairment and cancer. The favorable effects of exercise on cardiovascular homeostasis can be at least in part ascribed to the modulation of the neuro-hormonal systems implicated in cardiovascular pathophysiology. In the elderly, exercise has been shown to affect catecholamine secretion and biosynthesis, to positively modulate the renin-angiotensin-aldosterone system and to reduce the levels of plasma brain natriuretic peptides. Moreover, drugs modulating the neuro-hormonal systems may favorably affect physical capacity in the elderly. Thus, efforts should be made to actually make physical activity become part of the therapeutic tools in the elderly.

Acute and chronic effects of resistance exercise on blood pressure in elderly women and the possible influence of ACE I/D polymorphism

This study investigated the chronic effect of blood pressure (BP) and post-exercise hypotension (PEH) during resistance training (RT) and its relation with the angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism in hypertensive elderly women. Participants were divided into two groups: an experimental group (EG) with exercise and a control group (CG) without exercise. The EG performed one adaptation month and one repetition maximum load (1RM) test at the end of this period. After the first month, the EG conducted a three-month program of RT at 60%, 70%, and 80% of 1RM, respectively, for each month. The CG was evaluated at the end of each month. Systolic (SBP) and diastolic (DBP) blood pressure (Microlife BP 3AC1-1) were measured, with the subject in a seated position, during an acute session for both GE and CG as follows: every 5 minutes for 20 minutes at pre-exercise rest, immediately after the resistance exercise and control, and every 15 minutes during 1 hour of recovery after exercise and CG. Analysis of covariance showed reduction in SBP and DBP (P ≤ 0.05) rest values after the RT program. PEH was observed only for the EG in acute sessions, for SBP after the second and third months (P ≤ 0.05), and for DBP after the second and fourth months (P ≤ 0.05). No significant differences in main effects and interaction effects between blood pressure and ACE I/D were observed. The occurrence of chronic reduction of blood pressure and PEH through EG may have a protective effect on the cardiovascular system with no ACE I/D polymorphism influence for this population.

Exercise training, genetics and type 2 diabetes-related phenotypes

Type 2 diabetes mellitus (T2DM) is at virtually pandemic levels world-wide. Diabetes has been referred to as 'a geneticist's nightmare'. However, dramatic advances in our understanding of the genetics of T2DM have occurred in the past 5 years. While endurance exercise training and increased habitual physical activity levels have consistently been shown to improve or be associated with improved T2DM-related phenotypes, there is substantial interindividual variation in these responses. There is some evidence that T2DM-related phenotype responses to exercise training are heritable, indicating that they might have a genetic basis. Genome-wide linkage studies have not identified specific chromosomal loci that could account for these differences, and no genome-wide association studies have been performed relative to T2DM-related phenotype responses to exercise training. From candidate gene studies, there are relatively strong and replicated data supporting a role for the PPARγ Pro12Ala variant in the interindividual differences in T2DM-related phenotype responses to training. This is a potentially important candidate locus because it affects T2DM susceptibility, has high biological plausibility and is the target for the primary pharmaceutical method for treating T2DM. Is it time to conduct a hypothesis-driven large-scale exercise training intervention trial based on PPARγ Pro12Ala genotype with T2DM-related phenotypes as the primary outcome measures, while also assessing potential mechanistic changes in skeletal muscle and adipose tissue? Or would it be more appropriate to propose a smaller trial to address the specific skeletal muscle and adipose tissue mechanisms affected by the interaction between the PPARγ Pro12Ala genotype and exercise training?

Angiotensin-converting enzyme inhibitor use by older adults is associated with greater functional responses to exercise

OBJECTIVES

To assess the association between angiotensin converting enzyme inhibitors (ACEis) and improvements in the physical function of older adults in response to chronic exercise training.

DESIGN

Secondary analysis of the Lifestyle Interventions and Independence for Elders Pilot (LIFE-P) study, a multisite randomized clinical trial to evaluate the effects of chronic exercise on the physical function of older adults at risk for mobility disability.

SETTING

Four academic research centers within the United States.

PARTICIPANTS

Four hundred twenty-four individuals aged 70 to 89 with mild to moderate functional impairments categorized for this analysis as ACEi users, users of other antihypertensive drugs, or antihypertensive nonusers.

INTERVENTION

A 12-month intervention of structured physical activity (PA) or health education promoting successful aging (SA).

MEASUREMENTS

Change in walking speed during a 400-m test and performance on a battery of short-duration mobility tasks (Short Physical Performance Battery (SPPB)).

RESULTS

Physical activity significantly improved the adjusted walking speed of ACEi users (P < .001) but did not of nonusers. PA improved the adjusted SPPB score of ACEi users (P < .001) and of persons who used other antihypertensive drugs (P = .005) but not of antihypertensive nonusers (P = .91).The percentage of ACEi users deriving clinically significant benefit from exercise training for walking speed (30%) and SPPB score (48%) was dramatically higher than for nonusers (14% and 12%, respectively).

CONCLUSION

For older adults at risk for disability, exercise-derived improvements in physical function were greater for ACEi users than users of other antihypertensive drugs and antihypertensive nonusers.

The ACE gene and human performance: 12 years on

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

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.

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.

Sport therapy for hypertension: why, how, and how much?

Exercise may prevent or reduce the effects of metabolic and cardiovascular diseases, including arterial hypertension. Both acute and chronic exercise, alone or combined with lifestyle modifications, decrease blood pressure and avoid or reduce the need for pharmacologic therapy in patients with hypertension. The hypotensive effect of exercise is observed in a large percentage of subjects, with differences due to age, sex, race, health conditions, parental history, and genetic factors. Exercise regulates autonomic nervous system activity, increases shear stress, improves nitric oxide production in endothelial cells and its bioavailability for vascular smooth muscle, up-regulates antioxidant enzymes. Endurance training is primarily effective, and resistance training can be combined with it. Low-to-moderate intensity training in sedentary patients with hypertension is necessary, and tailored programs make exercise safe and effective also in special populations. Supervised or home-based exercise programs allow a nonpharmacological reduction of hypertension and reduce risk factors, with possible beneficial effects on cardiovascular morbidity.

Improved weight management using genetic information to personalize a calorie controlled diet

Background

Gene-environment studies demonstrate variability in nutrient requirements depending upon individual variations in genes affecting nutrient metabolism and transport. This study investigated whether the inclusion of genetic information to personalize a patient's diet (nutrigenetics) could improve long term weight management.

Methods

Patients with a history of failures at weight loss were offered a nutrigenetic test screening 24 variants in 19 genes involved in metabolism. 50 patients were in the nutrigenetic group and 43 patients attending the same clinic were selected for comparison using algorithms to match the characteristics: age, sex, frequency of clinical visits and BMI at initial clinic visit. The second group of 43 patients did not receive a nutrigenetic test. BMI reduction at 100 and > 300 days and blood fasting glucose were measured.

Results

After 300 days of follow-up individuals in the nutrigenetic group were more likely to have maintained some weight loss (73%) than those in the comparison group (32%), resulting in an age and gender adjusted OR of 5.74 (95% CI 1.74–22.52). Average BMI reduction in the nutrigenetic group was 1.93 kg/m²(5.6% loss) vs. an average BMI gain of 0.51 kg/m²(2.2% gain) (p < 0.023). Among patients with a starting blood fasting glucose of > 100 mg/dL, 57% (17/30) of the nutrigenetic group but only 25% (4/16) of the non-tested group had levels reduced to < 100 mg/dL after > 90 days of weight management therapy (OR for lowering glucose to < 100 mg/dL due to diet = 1.98 95%CI 1.01, 3.87, p < 0.046).

Conclusion

Addition of nutrigenetically tailored diets resulted in better compliance, longer-term BMI reduction and improvements in blood glucose levels.

Epidemiological studies of exercise in diabetes prevention

Type 2 diabetes is one of the fastest growing public health problems in both developed and developing countries. It is estimated that the number of people with diabetes in the world will double in coming years, from 171 million in 2000 to 366 million in 2030. Cardiovascular disease accounts for more than 70% of total mortality among patients with type 2 diabetes. The associations of physical activity, physical fitness, and changes in the lifestyle with the risk of type 2 diabetes have been assessed by a number of prospective studies and clinical trials in the past decade. Several studies have also evaluated the joint associations of physical activity, body mass index, and glucose levels with the risk of type 2 diabetes. Prospective studies and clinical trials have shown that moderate or high levels of physical activity or physical fitness and changes in the lifestyle (dietary modification and increase in physical activity) can prevent type 2 diabetes. Our review of the scientific evidence confirms that 30 min/d of moderate- or high-level physical activity is an effective and safe way to prevent type 2 diabetes in all populations.

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.

Exercise, genetics and prevention of type 2 diabetes

Type 2 diabetes is one of the fastest growing public health problems in both developed and developing countries. Cardiovascular disease is the most prevalent complication of type 2 diabetes. In the past decade, the associations of physical activity, physical fitness and changes in the lifestyle with the risk of type 2 diabetes have been assessed by a number of prospective studies and clinical trials. A few studies have also evaluated the joint associations of physical activity, body mass index and glucose levels with the risk of type~2 diabetes. The results based on prospective studies and clinical trials have shown that moderate or high levels of physical activity or physical fitness and changes in the lifestyle (dietary modification and increase in physical activity) can prevent type 2 diabetes.

Limitation of the homeostasis model assessment to predict insulin resistance and beta-cell dysfunction in older people

CONTEXT

Studies in older people have shown inconsistent agreement between homeostasis model assessment of insulin resistance (HOMA-IR) and dynamic measures of insulin action and have not evaluated HOMA beta-cell.

OBJECTIVE

We compared measures of insulin sensitivity and beta-cell function from the frequently sampled iv glucose tolerance test (FSIGT) to HOMA models. DESIGN/PATIENTS/SETTING/INTERVENTION: Two hundred fourteen young and old with normal glucose tolerance (NGT) and old with impaired glucose tolerance (IGT) participated in a retrospective analysis of FSIGT data in a university medical setting.

MAIN OUTCOME MEASURE

Sensitivity to insulin (S(I)) and acute insulin response to glucose (AIRg) from FSIGT were compared with HOMA models.

RESULTS

S(I) and HOMA-IR measures identified similar patterns of increasing insulin resistance in the two older groups, compared with younger people with NGT, with the greatest degree of insulin resistance in older people with IGT (P < 0.05 vs. young and old NGT for both S(I) and HOMA-IR). Agreement between HOMA-IR and S(I) was moderate (weighted kappa = 0.51). AIRg was similar in young and old NGT but was markedly decreased in old IGT (P < 0.05 vs. young and old NGT). HOMA-beta-cell was similar in the three groups. Agreement between HOMA beta-cell and AIRg was weak (weighted kappa = 0.35).

CONCLUSIONS

HOMA-IR may detect age-related insulin resistance when comparing large populations of older people. However, dynamic testing appears to be necessary to quantitate diminished insulin secretion in older people.

Arterial stiffness is related to insulin resistance in nondiabetic hypertensive older adults

Hypertension, diabetes, obesity, and aging are associated with increased arterial stiffness. Both insulin resistance and hyperglycemia may contribute to the development of arterial stiffness. Older nondiabetic hypertensive adults were recruited to test the following hypotheses: (1) insulin resistance is associated with arterial stiffness, and (2) this relationship is independent of glucose tolerance status. Aortic pulse wave velocity (PWV), pulse pressure (PP), insulin sensitivity index (S(I), measured by insulin-assisted frequently sampled iv glucose test), glucose tolerance status, and abdominal fat mass were assessed in 37 older (23 male, 14 female, mean age 69.4 +/- 5.9 yr), nondiabetic, hypertensive adults after a 4-wk antihypertensive medication withdrawal. Both PWV and PP were negatively correlated with S(I) (r = -0.49, P = 0.002, and r = -0.38, P = 0.02, respectively). The mean PWV and PP in those with normal glucose tolerance were not significantly different from those with impaired glucose tolerance (9.8 +/- 2.4 vs. 10.0 +/- 3.1 m/sec, P = 0.79 and 71 +/- 17 vs. 72 +/- 18 mm Hg, P = 0.80, respectively). In multiple regression analysis, PWV and PP remained independently correlated with S(I) (P < 0.05) after adjusting for age, gender, fasting glucose, glucose tolerance status, body mass index, or abdominal fat mass. These results suggest that in hypertensive, nondiabetic, older adults, insulin resistance is associated with arterial stiffness independent of glucose tolerance status.

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.

Leptin and leptin receptor gene polymorphisms and changes in glucose homeostasis in response to regular exercise in nondiabetic individuals: the HERITAGE family study

We recently reported that a genomic region close to the leptin locus was linked to fasting insulin response to exercise training in nondiabetic white subjects. We tested the hypothesis that common exonic variants in the leptin (LEP) and leptin receptor (LEPR) genes modify the effects of regular physical activity on glucose homeostasis in nondiabetic whites (n = 397) and blacks (n = 143). In whites, exercise increased insulin sensitivity index (P = 0.041) and disposition index (P = 0.046) in the LEPR 109R allele carriers but not in the K109K homozygotes, increased glucose disappearance index more in the R109R homozygotes than in the K109 allele carriers (P = 0.039), and decreased fasting glucose only in the 109R allele carriers (P = 0.018). We also found an interaction between the LEP A19G and LEPR K109R polymorphisms on the change in fasting insulin in whites (P = 0.010). The association between the LEP A19G polymorphism and the change in insulin was evident only in the LEPR 109R carriers (P = 0.019). The decrease in insulin was strongest in the LEP A19A homozygotes who carried the LEPR 109R allele. Similar interaction was observed in blacks (P = 0.046). Variations in the LEP and LEPR genes are associated with the magnitude of the effects of regular exercise on glucose homeostasis in nondiabetic individuals.

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.