Beta 2 adrenergic receptor polymorphisms, at codons 16 and 27, and bronchodilator responses in adult Venezuelan asthmatic patients

A meta-analysis of the influence of ADRB2 genetic polymorphisms on albuterol (salbutamol) therapy in patients with asthma

AIMS

The associations of 2 nonsynonymous single nucleotide polymorphisms (Arg16Gly and Gln27Glu) in the adrenoceptor β2 (ADRB2) gene with response after albuterol use are conflicting. We conducted a meta-analysis to examine the cumulative evidence of the effects of these 2 variants on percent forced expiratory volume in 1 second (FEV1.0%) after albuterol use in asthma patients.

METHODS

We conducted a comprehensive literature search using MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials to identify studies examining the association between ADRB2 Arg16Gly and Gln27Glu and FEV1.0% shortly after albuterol administration. The individual study results were combined with weights based on the inverse variance method. This systematic review was registered in the PROSPERO (registration number: CRD42019074554).

RESULTS

Among 273 initial studies identified, 7 studies met the inclusion criteria for quantitative evaluation. Results of the overall meta-analysis indicated no statistically significant mean difference of FEV1.0% between genotypes of Arg16Gly and Gln27Glu. In subgroup analyses, significant associations were found for Arg16Gly GG (vs AA) among studies where no methacholine bronchoconstriction was conducted (mean difference, -3.92; 95% confidence interval, -7.29 to -0.54; I² = 0%), and for Arg16Gly GG (vs GA) among studies that included patients with no comorbidities (mean difference, -1.93; 95% confidence interval, -3.77 to -0.10; I² = 0%).

CONCLUSION

Synthesis of the studies to date shows weak evidence for an association between ADRB2 Arg16Gly and Gln27Glu and FEV1.0% after albuterol use, results of which underscore significant heterogeneity across studies and the need for careful design and sample size considerations.

Genetic variability of five ADRB2 polymorphisms among Mexican Amerindian ethnicities and the Mestizo population

The Mexican population is characterized by high and particular admixture, and the picture of variants associated with disease remains unclear. Here we investigated the distribution of single nucleotide polymorphisms (SNPs) in the Mexican population. We focused on two non-synonymous and three synonymous SNPs in the beta-2 adrenergic receptor gene (ADRB2), which plays key roles in energy balance regulation. These SNPs were genotyped in 2,011 Mexican Amerindians (MAs) belonging to 62 ethnic groups and in 1,980 geographically matched Mexican Mestizos (MEZs). The frequency distribution of all five ADRB2 variants significantly differed between MAs, MEZs, and other continental populations (CPs) from the 1000 Genomes database. Allele frequencies of the three synonymous SNPs rs1042717A, rs1042718A, and rs1042719C were significantly higher in Mexican individuals, particularly among MAs, compared to in the other analyzed populations (P<0.05). The non-synonymous ADRB2 Glu27 allele (rs1042714G), which is associated with several common conditions, showed the lowest frequency in MAs (0.03) compared to other populations worldwide. Among MEZs, this allele showed a frequency of 0.15, intermediate between that in MAs and in Iberians (0.43). Moreover, Glu27 was the only SNP exhibiting a geographic gradient within the MEZ population (from 0.22 to 0.11), reflecting admixed mestizo ancestry across the country. Population differentiation analysis demonstrated that Glu27 had the highest F_ST value in MAs compared with Europeans (CEU) (0.71), and the lowest between MAs and Japanese (JPT) (0.01), even lower than that observed between MAs and MEZs (0.08). This analysis demonstrated the genetic diversity among Amerindian ethnicities, with the most extreme F_ST value (0.34) found between the Nahuatls from Morelos and the Seris. This is the first study of ADRB2 genetic variants among MA ethnicities. Our findings add to our understanding of the genetic contribution to variability in disease susceptibility in admixed populations.

Association of β2-adrenergic receptor gene polymorphisms (rs1042713, rs1042714, rs1042711) with asthma risk: a systematic review and updated meta-analysis

Background

The published data on the association between β2-adrenergic receptor gene polymorphisms and asthma susceptibility are inconclusive. To derive a more precise estimation of this association, a meta-analysis was performed.

Methods

A literature search was conducted in PubMed, Web of Science, EMBASE, Wanfang, and the China National Knowledge Infrastructure (CNKI) databases to identify eligible studies. The pooled odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were used to calculate the strength of the association. A sensitivity analysis was performed to evaluate the influence of individual studies on the overall effect estimates, and funnel plots and Egger’s tests were used for indications of publication bias.

Results

Seventy three studies with three single nucleotide polymorphisms (SNP) (rs1042713, c.G46A, p.Gly16Arg; rs1042714, c.G79C, p.Gln27Glu; rs1042711, c.T-47C, p.Cys19Arg) were finally identified. For the rs1042713 polymorphism, no significant association with asthma risk was found in the overall population. However, a significant protective association was found in the Indian population in the dominant model comparison (OR = 0.72, 95% CI = 0.59–0.87, I² = 25%, studies = 5, cases = 1190, controls = 1241). A significant risk association was found in the Arab population in the dominant model comparison (OR = 1.75, 95% CI = 1.14–2.70, I² = 0%, studies = 2, cases = 307, controls = 361) and the homozygote model comparison (OR = 1.88, 95% CI = 1.17–3.02, I² = 0%, studies = 2, cases = 307, controls = 361), and in the Hispanic-Latino population in the dominant model comparison (OR = 1.68, 95% CI = 1.10–2.55, I² = 77%, studies = 5, cases = 1026, controls = 1412). For the rs1042714 polymorphism, we found a significant association in the recessive model comparison (OR = 0.83, 95% CI = 0.70–0.98, I² = 44%, studies = 52, cases = 8242, controls = 16,832), the homozygote genotype comparison (OR = 0.84, 95% CI = 0.72–0.98, I² = 25%, studies = 52, cases = 8242, controls = 16,832) and the allelic genetic model (OR = 0.91, 95% CI = 0.83–0.99, I² = 59%, studies = 52, cases = 8242, controls = 16,832) in the overall population. When stratified by age, a significant association was also found in children in the recessive model comparison (OR = 0.59, 95% CI = 0.39–0.88, I² = 58%, studies = 18, cases = 2498, controls = 2510) and the homozygote genotype comparison (OR = 0.63, 95% CI = 0.43–0.92, I² = 46%, studies = 18, cases = 2498, controls = 2510), but not in adult. For the rs1042711 polymorphism, no significant associations were found in the any genetic model.

Conclusion

The meta-analysis suggests that the ADRB2 rs1042714 polymorphism has a protective association with asthma in the overall population and the pediatric subgroup.

The Influence of Beta-2 Adrenergic Receptor Gene Polymorphisms on Albuterol Therapy for Patients With Asthma: Protocol for a Systematic Review and Meta-Analysis

Background

Albuterol is one of the most frequently used medications in clinical practice and seeing varying responses to albuterol between individuals is not uncommon. Multiple studies have been conducted to investigate the associations of differing responses due to albuterol, particularly with regards to the two nonsynonymous single nucleotide polymorphisms (SNPs) at positions 16 (Arg16Gly: substitution of arginine to glycine at position 16; rs1042713) and 27 (Glu27Gln: substitution of glutamic acid to glutamine at position 27; rs1042714) on the β-2 adrenergic receptor (ADRB2) gene. However, the directions of the correlations are conflicting.

Objective

The objective of this systematic review and meta-analysis is to assess the effect of the two SNPs on the ADRB2 gene, in terms of the responses that present in asthmatic patients shortly after albuterol inhalation.

Methods

The primary outcome of this work is a detailed study of the associations of the two SNPs in the ADRB2 gene with treatment response and lung function testing shortly after administration of albuterol to asthmatic patients. A comprehensive literature search, using the OVID platform, MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials, will be conducted by a specialized librarian without language restrictions. We will include both prospective and retrospective original observational studies, and we will exclude nonhuman or in vitro studies. All abstracts will be reviewed by two authors who will also individually perform data extraction from each eligible study. Any arising disagreements will be resolved through discussion with a third party. Risk of bias for all included studies will be independently assessed using the quality of genetic association studies tool. We will report the systematic review and meta-analysis, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. A narrative synthesis of study results or meta-analyses will be undertaken when appropriate.

Results

At the moment of writing, we have already started the preliminary literature search and piloting of the study selection process. The anticipated completion date is September 30, 2019.

Conclusions

Our systematic review and meta-analysis aims to clarify the current evidence of associations between the two nonsynonymous SNPs in the ADRB2 gene and the responses that present in asthmatic patients shortly after albuterol inhalation. If positive correlations are found, this knowledge may be used to improve personalized pharmacotherapy of albuterol use.

Trial Registration

PROSPERO CRD42019074554; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=74554

International Registered Report Identifier (IRRID)

PRR1-10.2196/14759

Beta 2 Adrenergic Receptor Genetic Polymorphisms in Bronchial Asthma: Relationship to Disease Risk, Severity, and Treatment Response

BACKGROUND

The β₂-adrenergic receptor gene is one of the most extensively studied genes with respect to asthma prevalence and severity. The Arg16Gly and Gln27Glu polymorphisms in the β₂-adrenergic receptor gene cause changes in the amino acids sequence of the receptor which may cause alteration in response to bronchodilators and the risk of asthma.

OBJECTIVE

The purpose of the study was to determine the association between β₂-adrenergic receptor gene polymorphisms and asthma risk, severity and response to therapy.

SUBJECTS AND METHODS

58 asthmatic patients and 38 healthy subjects were included. The β₂-adrenergic receptor polymorphisms genotyping was done using Real-Time polymerase chain reaction.

RESULTS

The allelic frequencies for the Arg16Gly polymorphism were 15.5%, 48.3%, and 36.2% for the homozygous A wild, heterozygous, and homozygous G mutant alleles in asthmatics (P < 0.01) and 5.3%, 47.4%, and 47.4% in healthy subjects (P < 0.01). For the Gln27Glu polymorphism, the allelic frequencies for the homozygous C wild, heterozygous and homozygous G mutant alleles were 51.7%, 41.4%, and 6.9% in asthmatics (P < 0.01) and 44.7%, 39.5%, and 15.8% in healthy subjects (P < 0.01). The heterozygous Arg16Gly and Gln27Glu were found in most of severe asthma cases (7/13, 53.8% each). While homozygous wild and mutant seemed to be protective and associated with mild disease in both alleles. Finally, 75% of Arg16Gly heterozygous group were good responders (P < 0.01), 81% of homozygous G mutant were bad responders. For Gln27Glu polymorphism, 60% of C wild group were good responders and 75% of G mutant group were bad responders.

CONCLUSIONS

The findings suggest that the Arg16Gly and Gln27Glu polymorphisms in the β2-AR gene are associated with asthma severity and response to therapy and might be used in personalized treatment for these patients in the future. This work is registered in ClinicalTrial.gov with ID: NCT03118869.

B2 adrenergic receptor gene polymorphism effect on childhood asthma severity and response to treatment

BackgroundAlterations of B2 adrenergic receptor (β₂AR) can modulate the severity of asthma and the response to treatment. Therefore, we aimed to evaluate β₂AR gene polymorphism at codons 16 and 27 and their effect on asthma severity and response to treatment in asthmatic children.MethodsCase-control study was conducted on 156 children; 104 of them had bronchial asthma and 52 were healthy children (control group). Subjects of the study underwent history taking, clinical examination, pulmonary function tests, serum IgE level assessment, and identification of β₂AR-16 A46G and β₂AR-27 C79G polymorphism using PCR-Restriction Fragment length polymorphisms (RFLP) test.ResultsThere was a higher frequency of Arg-Gly genotypes (odds ratio (OR)=6.57; confidence interval (CI): 2.42-18.81, P<0.001) and lower frequency of Arg-Arg (OR=4.7; CI: 2.05-10.95, P<0.001) among asthmatic children compared with that among controls at codon 16. The presence or absence of Gly16 or Glu27 either homozygous or heterozygous for both correlated with the grade of asthma severity. The presence of heterozygous Arg-Gly and Gln-Glu gives a better response to drug therapy than the presence of Gly-Gly and Glu-Glu genotypes at codons 16 and 27.ConclusionPolymorphism of β₂AR at codons 16 and 27 correlates with asthma severity and response to treatment in asthmatic children.

Beta2-adrenergic receptor gene haplotypes and bronchodilator response in Egyptian patients with chronic obstructive pulmonary disease

PURPOSE

Chronic obstructive pulmonary disease (COPD) is a multi-factorial disorder caused by environmental determinants and genetic risk factors. Understanding the genetic predisposition of COPD is essential to develop personalized treatment regimens. Beta₂-adrenergic receptor (ADRB2) gene polymorphisms have been implicated in the pathogenesis of obstructive pulmonary diseases. This study was conducted to assess the genetic association between Arg16Gly and Gln27Glu polymorphisms and COPD in the Egyptian patients, and to analyze their impact on the clinical outcome and therapeutic response.

PATIENTS/METHODS

The study population included 115 participants (61 COPD patients and 54 healthy controls) were genotyped for the Arg16Gly (rs1042713) and Gln27Glu (rs1042714) polymorphisms. Pulmonary function test was done and repeated in patients after salbutamol inhalation.

RESULTS

The Gly₁₆ and Gln₂₇ alleles represented 57% and 70% of the whole study population, and only 3 haplotypes were detected; Arg₁₆/Gln₂₇, Gly₁₆/Gln₂₇, and Gly₁₆/Glu₂₇. Genotypes and haplotypes homozygous for Arg₁₆ and Gln₂₇ were more likely to develop COPD (p<0.05). However, individuals carrying Glu₂₇ allele conferred protection against COPD development (p=0.002). Furthermore, Arg₁₆ genotypes and haplotypes were significantly associated with higher grades of dyspnea, more COPD symptoms and frequent exacerbations. In contrast, patients carrying Glu₂₇ allele had better bronchial airway responsiveness to β₂-agonists.

CONCLUSIONS

Our findings suggested that the ADRB2 gene polymorphisms may have vital role in COPD risk, severity, and bronchodilator response among Egyptian population. Larger epidemiological studies are needed for results validation.

Polymorphisms in Beta-2 Adrenergic Receptor Gene and Association with Tuberculosis

PURPOSE

Genetic susceptibility for tuberculosis in human has been previously demonstrated. Polymorphisms in genes involved in immune responses may alter the susceptibility of individuals to tuberculosis. Polymorphisms of beta-2 adrenergic receptor (ADRB2) gene can be possibly an important risk factor in tuberculosis. In this study, the association between rs1042713 (Arg16Gly +46A>G) and rs1042714 (Gln27Glu +79C>G) polymorphisms in ADRB2 gene and tuberculosis was evaluated.

METHODS

Genotype distributions of the rs1042713 (Arg16Gly +46A>G) and rs1042714 (Gln27Glu +79C>G) polymorphisms in ADRB2 gene in 106 patients with pulmonary tuberculosis and 88 healthy subjects were studied by PCR-RFLP method in an Iranian population.

RESULTS

The frequency of rs1042713*G and rs1042714*G alleles in ADRB2 gene in tuberculosis patients was significantly different from healthy controls [odds ratio (OR) 0.176, 95% confidence interval (CI) 0.065-0.48, P value <0.001 and OR 0.45, 95% CI 0.247-0.825, P value = 0.009, respectively]. There were no significant differences in haplotype analysis between the patients and control subjects.

CONCLUSION

The association was reported between rs1042713 and rs1042714 polymorphisms in ADRB2 gene and tuberculosis for the first time. rs1042713*G and rs1042714*G polymorphisms in ADRB2 gene makes people more susceptible to develop the disease.

Analysis of ADRB2 (Arg16Gly) Gene Variant with Susceptibility, Pharmacogenetic Response and Disease Severity in South Indian Asthmatics

β2-Adrenergic receptor (β2-AR) plays a crucial role in asthma pathophysiology by regulating, processes of the lung function, and clinical response to bronchodilators. The +46G>A- Gly16Arg polymorphism in the gene encoding β2 adrenergic receptor (ADRB2) has been associated with receptor non-responsiveness after β2-agonist exposure. In the present study, we sought to evaluate the possible association of Gly16Arg polymorphism with asthma susceptibility, pharmacogenetic response to Salbutamol, and varying degrees of disease severity. Three hundred ninety-eight clinically diagnosed patients and 456 healthy controls were enrolled for the study. Patients were classified into severity classes according to Global Initiative for Asthma guidelines. To assess bronchodilator response, spirometry was performed before and 15 min after Salbutamol (200 μg) delivery. Responders to Salbutamol were categorized if percentage reversibility was greater than or equal to 12% in them, while those showing reversibility less than 12% were classified as non-responders. Genotyping was carried out by ARMS-PCR technique. Statistical methods were applied to test for the significance of the results. In the present study, there was lack of significant association of polymorphism with disease susceptibility as well as with bronchodilator response. The polymorphism was not associated with mild and moderate asthma subtypes; however, there was a notable association with severe asthma subtype. In addition, the polymorphism was associated with severe asthma compared to subtypes of mild and moderate asthma combined. In a South Indian population, the ADRB2 Arg/Gly may not form a susceptible variant to develop asthma nor can be a standard predictive marker to bronchodilator response; nevertheless, the patterns in asthma severity can be predicted by analyzing this variant.

Beta-2 adrenergic receptor (ADRB2) gene polymorphisms and the risk of asthma: a meta-analysis of case-control studies

BACKGROUND AND OBJECTIVE

A number of studies have assessed the relationship between beta-2 adrenergic receptor (ADRB2) gene polymorphisms and asthma risk. However, the results are inconsistent. A meta-analysis that focused on the association between asthma and all ADRB2 polymorphisms with at least three case-control studies was thus performed.

METHODS

A literature search of the PubMed, Embase, Web of Science, CNKI, and Wangfang databases was conducted. Odds ratios with 95% confidence intervals were used to assess the strength of associations.

RESULTS

Arg16Gly, Gln27Glu, Thr164Ile, and Arg19Cys single nucleotide polymorphisms (SNPs) were identified in 46 case-control studies. The results showed that not all of the SNPs were associated with asthma in the overall population. Significant associations were found for the Arg16Gly polymorphism in the South American population via dominant model comparison (OR = 1.754, 95% CI = 1.179-2.609, I2 = 16.9%, studies  = 2, case  = 314, control  = 237) in an analysis stratified by ethnicity. For the Gln27Glu polymorphism, a protective association was found in children via recessive model comparison (OR = 0.566, 95% CI = 0.417-0.769, I2 = 0.0%, studies  = 11, case  = 1693, control  =  502) and homozygote genotype comparison (OR = 0.610, 95% CI = 0.434-0.856, I2 = 0.0%, studies  = 11, case  = 1693, control  = 1502), and in adults via dominant model comparison (OR = 0.864, 95% CI = 0.768-0.971, I2 = 46.9%, n = 18, case  = 3160, control  = 3433).

CONCLUSIONS

None of the ADRB2 gene polymorphisms were reproducibly associated with a risk of asthma across ethnic groups in the general population.