Lifestyle modifies the relationship between body composition and adrenergic receptor genetic polymorphisms, ADRB2, ADRB3 and ADRA2B: a secondary analysis of a randomized controlled trial of physical activity among postmenopausal women

Effects of the Trp64Arg Polymorphism in the ADRB3 Gene on Body Composition, Cardiorespiratory Fitness, and Physical Activity in Healthy Adults

The ADRB3 gene plays a role in energy expenditure by participating in lipolysis, which affects body composition and performance. The ADRB3 rs4994 polymorphism has been studied in groups of athletes, overweight individuals, and obese and diabetic patients, but it has not been studied in young and healthy adults so far. In the present study, we examined the association of ADRB3 rs4994 polymorphism with body composition, somatotype, cardiorespiratory fitness and physical activity in young, healthy adults (N = 304). All subjects had anthropometric measurements, and somatotypes were assessed using the Heath-Carter method. In addition, cardiorespiratory fitness and physical activity levels were assessed. Genotyping for the ADRB3 gene was performed using a PCR-RFLP method. In the male group, body components were associated with the Trp64Trp genotype (waist circumference (p = 0.035), hip circumference (p = 0.029), BF (%) (p = 0.008), and BF (kg) (p = 0.010), BMI (p = 0.005), WHtR (p = 0.021), and BAI (p = 0.006)). In addition, we observed that the Trp64Trp genotype was associated with somatotype components (p = 0.013). In contrast, the Arg allele was associated with the ectomorphic components (0.006). We also observed a positive impact of the Trp64Trp genotype with maximal oxygen uptake (p= 0.023) and oxygen pulse (p = 0.024). We observed a negative relationship of the Trp64Trp genotype in the female group with reported moderate-intensity exercise (p = 0.036). In conclusion, we found an association of the Trp64 allele with anthropometric traits, somatotype and parameters describing physical performance in the male group. In the female subpopulation, we only found an effect of the polymorphism Trp64Arg on the level of physical activity for moderate-intensity exercise.

Comparison of visceral fat lipolysis adaptation to high-intensity interval training in obesity-prone and obesity-resistant rats

BACKGROUND/OBJECTIVES

Visceral obesity is one of the key features of metabolic syndrome. High-intensity interval training (HIIT) could effectively reduce visceral fat, but its effects show strong heterogeneity in populations with different degrees of obesity. The mechanism may be related to the differential adaptation to training between obesity phenotypes, namely obesity prone (OP) and obesity resistant (OR). The aim of the present study was to compare adaptive changes of visceral adipose lipolysis adaptation to HIIT between OP and OR animals and further explore the upstream pathway.

METHODS

OP and OR Sprague Dawley rats were established after feeding a high-fat diet for 6 weeks; they were then divided into HIIT (H-OP and H-OR) and control (C-OP and C-OR) groups. After 12 weeks of HIIT or a sedentary lifestyle, animals were fasted for 12 h and then sacrificed for histology as well as gene and protein analysis. Visceral adipocytes were isolated without fasting for catecholamine stimulation and β3-adrenergic receptor (β3-AR) blockade in vitro to evaluate the role of upstream pathways.

RESULTS

After training, there were no differences in weight loss or food intake between OP and OR rats (P > 0.05). However, the visceral fat mass, adipocyte volume, serum triglycerides and liver lipids of OP rats decreased by more than those of OR rats (P < 0.05). Meanwhile, the cell lipolytic capacity and the increase in the expression of β3-AR were higher in the OP compared with OR groups (P < 0.05). Although training did not increase sympathetic nervous system activity (P > 0.05), the cell sensitivity to catecholamine increased significantly in the OP compared with OR groups (P < 0.05). Following blocking β3-AR, the increased sensitivity disappeared.

CONCLUSION

With HIIT, OP rats lost more visceral fat than OR rats, which was related to stronger adaptive changes in lipolysis. Increased β3-AR expression mediated this adaptation.

An intron variant of the GLI family zinc finger 3 (GLI3) gene differentiates resistance training-induced muscle fiber hypertrophy in younger men

We examined the association between genotype and resistance training-induced changes (12 wk) in dual x-ray energy absorptiometry (DXA)-derived lean soft tissue mass (LSTM) as well as muscle fiber cross-sectional area (fCSA; vastus lateralis; n = 109; age = 22 ± 2 y, BMI = 24.7 ± 3.1 kg/m² ). Over 315 000 genetic polymorphisms were interrogated from muscle using DNA microarrays. First, a targeted investigation was performed where single nucleotide polymorphisms (SNP) identified from a systematic literature review were related to changes in LSTM and fCSA. Next, genome-wide association (GWA) studies were performed to reveal associations between novel SNP targets with pre- to post-training change scores in mean fCSA and LSTM. Our targeted investigation revealed no genotype-by-time interactions for 12 common polymorphisms regarding the change in mean fCSA or change in LSTM. Our first GWA study indicated no SNP were associated with the change in LSTM. However, the second GWA study indicated two SNP exceeded the significance level with the change in mean fCSA (P = 6.9 × 10^-7 for rs4675569, 1.7 × 10^-6 for rs10263647). While the former target is not annotated (chr2:205936846 (GRCh38.p12)), the latter target (chr7:41971865 (GRCh38.p12)) is an intron variant of the GLI Family Zinc Finger 3 (GLI3) gene. Follow-up analyses indicated fCSA increases were greater in the T/C and C/C GLI3 genotypes than the T/T GLI3 genotype (P < .05). Data from the Auburn cohort also revealed participants with the T/C and C/C genotypes exhibited increases in satellite cell number with training (P < .05), whereas T/T participants did not. Additionally, those with the T/C and C/C genotypes achieved myonuclear addition in response to training (P < .05), whereas the T/T participants did not. In summary, this is the first GWA study to examine how polymorphisms associate with the change in hypertrophy measures following resistance training. Future studies are needed to determine if the GLI3 variant differentiates hypertrophic responses to resistance training given the potential link between this gene and satellite cell physiology.

Can study of the ADRB3 gene help improve weight loss programs in obese individuals?

INTRODUCTION

Obesity is a chronic disease of multifactorial origin characterized by excess weight and excess fat accumulation, and whose etiology includes intrinsic (genetic, physiological, and metabolic) and extrinsic (social and cultural) factors. Fat accumulation is caused by a prolonged imbalance in the energy balance influenced, among other factors, by adaptive thermogenesis, which is triggered by cold environmental conditions, or by hypercaloric intake. Thermogenesis is regulated by the sympathetic nervous system and occurs in the muscle and brown adipose tissue. There are adrenergic receptors in brown adipose tissue, including the beta-3 adrenergic receptor (ADRB3), the main receptor for the regulation of thermogenesis. The presence in heterozygosis of an SNP-type polymorphism in the ADRB3 gene (Trp64Arg; rs4994) is associated with a lower lipolytic activity, a predisposition to obesity, and resistance to weight loss. The objective of this study was to analyze through a systematic review the weight loss program most appropriate for carriers.

METHODS

A retrospective study of published papers on rs4994 polymorphism in the SNP and PubMed databases was conducted.

RESULTS

Most published studies suggest the presence of obesity and resistance to weight loss in carriers, and report significant improvements in anthropometric parameters when patients receive fat-rich hypocaloric diets.

CONCLUSIONS

Based on these conclusions, specific nutritional and physical exercise guidelines are proposed for individuals carrying the Trp64Arg allele.

12-Week aerobic exercise and nutritional program minimized the presence of the 64Arg allele on insulin resistance

BACKGROUND

The objective of the study was to investigate the response of 64Arg allele carriers of the ADRB3 gene (Trp64Arg polymorphism) in the anthropometric, cardiorespiratory and metabolic variables in overweight adolescents after a 12-week aerobic exercise and nutritional program.

METHODS

A total of 92 overweight adolescents, 10-16 years old and of both genders, participated. Body composition, waist circumference (WC), pubertal stage status, blood pressure, glucose, insulin and lipid profile and direct maximal oxygen uptake were assessed at baseline and after 12 weeks of a training program. The homeostasis metabolic assessments [homeostasis model assessment of insulin resistance (HOMA-IR)] and quantitative insulin sensitivity check index (QUICKI) were determined and the Trp64Arg polymorphism of the ADRB3 gene was investigated by Taqman single nucleotide polymorphism (SNP) genotyping assays. Exercise sessions consisted of 100-min aerobic exercise and 20-min stretching, 3 times a week, totalizing 36 sessions. Multivariate analysis of variance (MANOVA), analysis of covariance (ANCOVA) and effect size were used for variables, with p<0.05 considered significant.

RESULTS

In baseline, HOMA-IR was higher in carriers of the 64Arg allele and decreased more after 12 weeks than in non-carriers (p=0.01). The anthropometric, physical fitness and metabolic profiles had similar responses after training in carriers and non-carriers.

CONCLUSIONS

Overweight adolescents present changes in body composition and physical fitness, independent of Trp64Arg genotypes. However, a 12-week aerobic exercise and nutritional program promoted greater reductions in insulin resistance in carriers of the 64Arg allele.

Genetic Variant in ACVR2B Is Associated with Lean Mass

INTRODUCTION

Low lean mass (LM) is a risk factor for chronic disease, a major cause of disability and diminished quality of life, and is a heritable trait. However, relatively few specific genetic factors have been identified as potentially influencing this trait.

METHODS

In this study, we selected 1493 single-nucleotide polymorphisms (SNP) in 155 candidate genes involved in anabolic, catabolic, growth hormone, and other related pathways and examined their association with LM, assessed by dual-energy x-ray absorptiometry, in a sample of 2760 non-Hispanic and Hispanic white postmenopausal women from the Women's Health Initiative (WHI) Observational Study. We assessed the replication of our top findings in a meta-analysis of 20 genome-wide association studies (n = 38,292) conducted by the Cohorts for Heart and Aging Research in Genomic Epidemiology Consortium Musculoskeletal Working Group.

RESULTS

We identified 32 SNPs that had nominally significant associations with LM in the WHI cohort. In the replication stage, we find that SNP rs2276541 in the activin A receptor, type IIB (ACVR2B), was significantly associated with LM (β = 0.15, P = 2.17 × 10). ACVR2B codes for a receptor for a negative regulator of skeletal muscle, myostatin, and has previously been identified in a candidate gene study as a determinant of skeletal muscle mass.

CONCLUSIONS

Our findings support a previously proposed role of ACVR2B allelic variation as a determinant of muscle mass and extend prior findings in men and women. Additional large-scale studies will be needed to confirm our findings in different populations.

Influence of ADRB2 Gln27Glu and ADRB3 Trp64Arg polymorphisms on body weight and body composition changes after a controlled weight-loss intervention

The β-2 and β-3 adrenergic receptors (ADRB2 and ADRB3) are thought to play a role in energy expenditure and lipolysis. However, the effects of the ADRB2 glutamine (Gln) 27 glutamic acid (glutamate) (Glu) and ADRB3 tryptophan (Trp) 64 arginine (Arg) polymorphisms on weight loss remain controversial. The aim of this study was to investigate the effect of these polymorphisms on changes in weight and body composition during a controlled weight-loss program. One hundred seventy-three healthy overweight and obese participants (91 women, 82 men) aged 18-50 years participated in a 22-week-long intervention based on a hypocaloric diet and exercise. They were randomly assigned to 1 of 4 groups: strength, endurance, strength and endurance combined, and physical activity recommendations only. Body weight, body mass index (BMI), and body composition variables were assessed before and after the intervention. Genetic analysis was carried out according to standard protocols. No effect of the ADRB2 gene was shown on final weight, BMI, or body composition, although in the supervised male group, Glu27 carriers tended to have greater weight (p = 0.019, 2.5 kg) and BMI (p = 0.019, 0.88 kg/m(2)) reductions than did noncarriers. There seems to be an individual effect of the ADRB3 polymorphism on fat mass (p = 0.004) and fat percentage (p = 0.036), in addition to an interaction with exercise for fat mass (p = 0.038). After the intervention, carriers of the Arg64 allele had a greater fat mass and fat percentage than did noncarriers (p = 0.004, 2.8 kg). In conclusion, the ADRB2 Gln27Glu and ADRB3 Trp64Arg polymorphisms may influence weight loss and body composition, although the current evidence is weak; however, further studies are necessary to clarify their roles.

High genetic risk individuals benefit less from resistance exercise intervention

Background/Objectives

Genetic factors play an important role in body mass index (BMI) variation, and also likely play a role in the weight-loss and body composition response to physical activity/exercise. With the recent identification of BMI–associated genetic variants, it is possible to investigate the interaction of these genetic factors with exercise on body composition outcomes.

Subjects/Methods

In a block-randomized clinical trial of resistance exercise among women (n=148), we examined whether the putative effect of exercise on weight and DXA-derived body composition measurements differs according to genetic risk for obesity. Approximately one-half of the sample was randomized to an intervention consisting of a supervised, intensive, resistance exercise program, lasting one year. Genetic risk for obesity was defined as a genetic risk score (GRS) comprised of 21 SNPs known to be associated with normal BMI variation. We examined the interaction of exercise intervention and the GRS on anthropometric and body composition measurements after one year of the exercise intervention.

Results

We found statistically significant interactions for body weight (p=0.01), body fat (p=0.01), body fat % (p=0.02), and abdominal fat (p=0.02), whereby the putative effect of exercise is greater among those with a lower level of genetic risk for obesity. No single SNP appears to be a major driver of these interactions.

Conclusions

The weight-loss response to resistance exercise, including changes in body composition, differs according to an individual’s genetic risk for obesity.

Gene × environment interactions in obesity: the state of the evidence

BACKGROUND/AIMS

Obesity is a pervasive and highly prevalent disease that poses substantial health risks to those it affects. The rapid emergence of obesity as a global epidemic and the patterns and distributions of the condition within and between populations suggest that interactions between inherited biological factors (e.g. genes) and relevant environmental factors (e.g. diet and physical activity) may underlie the current obesity epidemic.

METHODS

We discuss the rationale for the assertion that gene × lifestyle interactions cause obesity, systematically appraise relevant literature, and consider knowledge gaps future studies might seek to bridge.

RESULTS

We identified >200 relevant studies, of which most are relatively small scale and few provide replication data.

CONCLUSION

Although studies on gene × lifestyle interactions in obesity point toward the presence of such interactions, improved data standardization, appropriate pooling of data and resources, innovative study designs, and the application of powerful statistical methods will be required if translatable examples of gene × lifestyle interactions in obesity are to be identified. Future studies, of which most will be observational, should ideally be accompanied by appropriate replication data and, where possible, by analogous findings from experimental settings where clinically relevant traits (e.g. weight regain and weight cycling) are outcomes.

Beta-3-adrenergic receptor Trp64Arg polymorphism: does it modulate the relationship between exercise and percentage of body fat in young adult Japanese males?

OBJECTIVES

The Trp64Arg polymorphism of the beta-3-adrenergic receptor gene has been studied as a potential genetic factor contributing to the development of obesity. Several studies have investigated whether or not this polymorphism affects weight reduction due to exercise, but the results of these studies have not been consistent. Moreover, information on a population characterized by a wide ranges of physical activities is scarce. Thus, to further understand the impact of this polymorphism, we examined whether the polymorphism modulates the relationship between physical activity due to exercise (PAE) and percentage of body fat (%BF).

METHODS

The study population was 70 Japanese male young adults with a high prevalence of habitual exercise. PAE was estimated by a questionnaire, and %BF was measured by bioelectrical impedance analysis. Genotyping was done by PCR-restriction fragment length polymorphism analysis.

RESULTS

The median PAE value of the subjects was 6.9 MET-h/day with an interquartile range of 1.5-10.3 MET-h/day. PAE correlated significantly with %BF in the entire population and within the two subpopulations, namely, carriers or non-carriers of the Arg allele. Multiple regression analysis of PAE, Trp64Arg polymorphism, and the interaction term revealed that while the PAE-derived independent variable was statistically significant, the interaction term was insignificant. When the two regression lines of subjects with and without the Arg allele were considered, the difference between the two slopes did not deviate from zero, nor did the vertical distance of the two regression lines. These findings suggest that the impact of this polymorphism is limited.

CONCLUSIONS

In our study population of young adult Japanese males, the impact of the Trp64Arg polymorphism on the association between exercise and body composition was weak, if it existed at all.

Genetic Influences on Physiological and Subjective Responses to an Aerobic Exercise Session among Sedentary Adults

Objective. To determine whether genetic variants suggested by the literature to be associated with physiology and fitness phenotypes predicted differential physiological and subjective responses to a bout of aerobic exercise among inactive but otherwise healthy adults. Method. Participants completed a 30-minute submaximal aerobic exercise session. Measures of physiological and subjective responding were taken before, during, and after exercise. 14 single nucleotide polymorphisms (SNPs) that have been previously associated with various exercise phenotypes were tested for associations with physiological and subjective response to exercise phenotypes. Results. We found that two SNPs in the FTO gene (rs8044769 and rs3751812) were related to positive affect change during exercise. Two SNPs in the CREB1 gene (rs2253206 and 2360969) were related to change in temperature during exercise and with maximal oxygen capacity (VO(2) max). The SLIT2 SNP rs1379659 and the FAM5C SNP rs1935881 were associated with norepinephrine change during exercise. Finally, the OPRM1 SNP rs1799971 was related to changes in norepinephrine, lactate, and rate of perceived exertion (RPE) during exercise. Conclusion. Genetic factors influence both physiological and subjective responses to exercise. A better understanding of genetic factors underlying physiological and subjective responses to aerobic exercise has implications for development and potential tailoring of exercise interventions.