Environmental Factors and Beta2-Adrenergic Receptor Polymorphism: Influence on the Energy Expenditure and Nutritional Status of Obese Women

Role of beta-2 adrenergic receptor polymorphism (rs1042714) on body weight and glucose metabolism response to a meal-replacement hypocaloric diet

OBJECTIVES

The beta-2 adrenergic receptor (ADRB2) is involved in energy balance regulation. The objective of our study was to evaluate the role of the rs1042714 genetic variant of ADRB2 gene on weight loss, body composition, and metabolic changes secondary to partial meal replacement (pMR) hypocaloric diet in women with obesity.

METHODS

We conducted an interventional study in 95 premenopausal women with body mass index ≥ 35 kg/m2. The subjects received two intakes per day of a normocaloric hyperproteic formula during 12 wk of a pMR diet. Body weight, body mass index, fat mass, waist circumference, lipid profile, fasting insulin levels, and homeostasis model assessment for insulin resistance were determined. All patients were genotyped rs1042714 and evaluated in a dominant model (CC versus CG + GG).

RESULTS

Genotype frequencies were 31 (37.3%), 38 (45.8%), and 14 (16.9%) for the CC, CG, and GG genotypes, respectively. We found significant interaction effects between ADRB2 variant and pMR-induced changes (CC versus CG + GG) on body weight (-7.1 ± 0.3 versus -13.5 ± 0.5 kg; P = 0.03), body mass index (-0.9 ± 0.1 versus -1.2 ± 0.2 kg/m2; P = 0.03), fat mass (-4.9 ± 0.5 versus -10.2 ±1.2 kg; P = 0.01), waist circumference (-5.1 ± 0.2 versus -10.1 ± 1.9 cm; P = 0.03), glucose (-5.1 ± 1.3 versus -12.5 ± 2.5 mg/dL; P = 0.03), total cholesterol (-18.1 ± 9.3 versus -33.5 ± 4.5 mg/dL; P = 0.03), low-density lipoprotein cholesterol (-9.1 ± 5.3 versus -24.5 ± 4.1 mg/dL; P = 0.04), triacylglycerol levels (-6.1 ± 5.3 versus -31.5 ± 9.5 mg/dL; P = 0.04), fasting insulin levels (-1.8 ± 0.3 versus -6.3 ± 0.5 IU/L; P = 0.03), and homeostasis model assessment for insulin resistance (-0.6 ± 0.3 versus -1.9 ± 0.5 U; P = 0.03). The odds ratio to improve alteration in glucose metabolism adjusted by age and weight loss throughout the study was 0.26 (95% CI, 0.07-0.95; P = 0.02) in G allele carriers.

CONCLUSIONS

The G allele of rs1042714 predicts the magnitude of weight loss resulting from a pMR diet. These adiposity improvements produce a better improvement of insulin resistance and percentage of impaired glucose metabolism in G allele carriers.

ADRB2 GLN27GLU POLYMORPHISM ASSOCIATED WITH ADIPOSITY INDICATORS AND IL-10 IN ADOLESCENTS

ABSTRACT Introduction: Studies of association between obesity and genetic factors have demonstrated a significant contribution of polymorphisms related to body fat distribution and subclinical inflammatory process. Objective: To investigate the association between genotypes of the Gln27Glu polymorphism of the ADRB2 gene and indicators of adiposity, inflammatory markers, metabolic parameters and parameters of physical fitness in overweight adolescents. Methods: A total of 44 male and female adolescents, aged between 13 and 17 years, with positive clinical diagnosis of overweight, were divided into two groups according to the Gln27Glu polymorphism genotypes of the ADRB2 gene: a) Group of carriers of the 27Glu allele (Gln27Glu/Glu27Glu) (n = 22); b) Group of non-carriers of the 27Glu allele (Gln27Gln) (n = 22). Both groups were evaluated for body composition, sexual maturation, cardiorespiratory fitness variables and indicators of muscle strength. Basal glycemia and insulin, lipid profile and inflammatory profile were measured. Abdominal subcutaneous and visceral adiposities were evaluated by ultrasonography. Genotyping of the Gln27Glu polymorphism of the ADRB2 gene was performed by the Taqman allelic discrimination assay. Results: The genotype frequency found was: Gln/Gln (n = 22) (50.0%), Gln/Glu (n = 18) (41.0%) and Glu/Glu (n = 4) %). The frequency of the 27Glu allele was 29.5%. The group of adolescent carriers of the 27Glu allele of the ADRB2 gene presented higher mean adiposity indicators (abdominal circumference, trunk fat mass and visceral fat), as well as lower IL-10 concentrations when compared to non-carriers. Conclusions: The 27Glu allele was associated with adiposity indicators in overweight adolescents, while subcutaneous abdominal fat exhibited an inverse relationship with inflammatory variables and maximum oxygen uptake, which may result in more damage to health. Level of evidence III; Case-control study.

Association of FTO and ADRB2 gene variation with energy restriction induced adaptations in resting energy expenditure and physical activity

Background

Energy restriction induces adaptations in resting energy expenditure (REE) and physical activity; inter-individual variability could be ascribed to genetic predisposition.The aim was to examine if changes in REE and physical activity as a result of weight loss were affected by candidate single nucleotide polymorphisms (SNPs).

Methods

148 subjects (39 men, 109 women), mean ± SD age: 41 ± 9 year; body mass index (BMI): 31.9 ± 3.0 kg/m², followed a very low energy diet for 8 weeks. SNPs were selected from six candidate genes: ADRB2, FTO, MC4R, PPARG2, PPARD and PPARGC1A. REE (ventilated hood) and physical activity (tri-axial accelerometer) were assessed before and after the diet. General linear modelling included gender, age and additional relevant covariates for all parameters.

Results

The heterozygotic genotype of FTO was associated with a higher amount of physical activity (1.71 Mcounts/d; CI 1.62-1.81) compared to the homozygotic major genotype (1.50 Mcounts/d; CI 1.40-1.59) (P < 0.001) while the homozygotic risk allele genotype was not different (1.56 Mcounts/d; CI 1.39-1.74) at baseline; moreover, a similar pattern was observed after energy restriction. Carrying the homozygotic minor genotype of ADRB2 was associated with a larger decrease in REE (P < 0.05) and greater adaptive thermogenesis (P < 0.05) after weight loss.

Conclusion

Carrying the minor ADRB2 allele homozygous was associated with a larger diet induced metabolic adaptation in energy expenditure and suggest a central role for reduced lipid mobilization. Carrying the risk allele of FTO homozygous was not associated with lower physical activity at baseline or after weight loss. Heterozygous carriers of one FTO risk allele showed greater physical activity before and after weight loss which might protect them in part from the higher obesity risk associated with FTO.

Differential lipid metabolism outcomes associated with ADRB2 gene polymorphisms in response to two dietary interventions in overweight/obese subjects

BACKGROUND AND AIMS

A precise nutrigenetic management of hypercholesterolemia involves the understanding of the interactions between the individual's genotype and dietary intake. The aim of this study was to analyze the response to two dietary energy-restricted interventions on cholesterol changes in carriers of two ADRB2 polymorphisms.

METHODS AND RESULTS

A 4-month nutritional intervention was conducted involving two different hypo-energetic diets based on low-fat (LF) and moderately high-protein (MHP) dietary patterns. A total of 107 unrelated overweight/obese individuals were genotyped for two ADRB2 non-synonymous polymorphisms: Arg16Gly (rs1042713) and Gln27Glu (rs1042714). Genotyping was performed by next-generation sequencing and haplotypes were phenotypically screened. Anthropometric measurements and the biochemical profile were assessed by conventional methods. Both diets induced cholesterol decreases at the end of both nutritional interventions. Interestingly, phenotypical differences were observed according to the Arg16Gly polymorphism. Within the MHP group, Gly16Gly homozygotes had lower reductions in total cholesterol (-6.5 mg/dL vs. -24.2 mg/dL, p = 0.009), LDL-c levels (-1.4 mg/dL vs. -16.5 mg/dL, p = 0.005), and non-HDL-c (-4.5 mg/dL vs. -21.5 mg/dL, p = 0.008) than Arg16 allele carriers. Conversely, within the LF group, Gly16Gly homozygotes underwent similar falls in total cholesterol (-18.5 mg/dL vs. -18.7 mg/dL, ns), LDL-c levels (-9.7 mg/dL vs. -13.1 mg/dL, ns), and non-HDL-c (-15.3 mg/dL vs. -15.7 mg/dL, ns) than Arg16 allele carriers. The Gln27Glu polymorphism and the Gly16/Glu27 haplotype showed similar, but not greater effects.

CONCLUSIONS

An energy-restricted LF diet could be more beneficial than a MHP diet to reduce serum cholesterol, LDL-c, and non-HDL-c among Gly16Gly genotype carriers. CLINICALTRIALS.GOV: Identifier: NCT02737267.

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.