β3-Adrenergic receptor Trp64Arg polymorphism does not predict incident CHD or carotid intima-media thickness in a community-based sample of whites: the ARIC study

Adrenergic gene polymorphisms and cardiovascular risk in the NHLBI-sponsored Women's Ischemia Syndrome Evaluation

BACKGROUND

Adrenergic gene polymorphisms are associated with cardiovascular and metabolic phenotypes. We investigated the influence of adrenergic gene polymorphisms on cardiovascular risk in women with suspected myocardial ischemia.

METHODS

We genotyped 628 women referred for coronary angiography for eight polymorphisms in the alpha1A-, beta1-, beta2- and beta3-adrenergic receptors (ADRA1A, ADRB1, ADRB2, ADRB3, respectively), and their signaling proteins, G-protein beta 3 subunit (GNB3) and G-protein alpha subunit (GNAS). We compared the incidence of death, myocardial infarction, stroke, or heart failure between genotype groups in all women and women without obstructive coronary stenoses.

RESULTS

After a median of 5.8 years of follow-up, 115 women had an event. Patients with the ADRB1 Gly389 polymorphism were at higher risk for the composite outcome due to higher rates of myocardial infarction (adjusted hazard ratio [HR] 3.63, 95% confidence interval [95%CI] 1.17-11.28; Gly/Gly vs. Arg/Arg HR 4.14, 95%CI 0.88-19.6). The risk associated with ADRB1 Gly389 was limited to those without obstructive CAD (n = 400, Pinteraction = 0.03), albeit marginally significant in this subset (HR 1.71, 95%CI 0.91-3.19). Additionally, women without obstructive CAD carrying the ADRB3 Arg64 variant were at higher risk for the composite endpoint (HR 2.10, 95%CI 1.05-4.24) due to subtle increases in risk for all of the individual endpoints. No genetic associations were present in women with obstructive CAD.

CONCLUSION

In this exploratory analysis, common coding polymorphisms in the beta1- and beta3-adrenergic receptors increased cardiovascular risk in women referred for diagnostic angiography, and could improve risk assessment, particularly for women without evidence of obstructive CAD.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00000554.

Effect of Trp64Arg mutation of the beta3-adrenergic receptor gene and C161T substitution of the peroxisome proliferator activated receptor gamma gene on obesity in Japanese children

OBJECTIVE

Obesity is a multifactorial syndrome influenced by both genetic and behavioral factors. Trp64Arg mutation of the beta3-adrenergic receptor (AR) gene and C161T substitution of the peroxisome proliferator-activated receptor (PPAR) gamma gene have been reported to be associated with obesity or lipid metabolism in adults. However, the effects of these mutations on children have not yet been clarified. For this reason, we studied the effects of Trp64Arg mutation of the beta3-AR gene and C161T substitution of the PPARgamma gene on obesity in Japanese children.

SUBJECTS AND METHODS

In order to determine the effects of Trp64Arg mutation of the beta3-AR gene and C161T substitution of the PPARgamma gene on obesity in children, 105 obese Japanese children were screened by the polymerase chain reaction and restriction fragment-length polymorphism analysis. Plasma lipid, apolipo-protein (apo), glucose, insulin and leptin levels were also determined.

RESULTS

Obese boys with Trp64Arg showed a higher obesity index and lower plasma levels of high-density lipoprotein cholesterol (HDL-C), apoA-I and apoA-II than those of them without the mutation. Obese boys with both mutations showed a higher plasma leptin level than those with only the beta3-AR gene mutation or PPARgamma gene mutation. No significant effect of these mutations was found in obese girls.

CONCLUSION

All of these data suggest that Trp64Arg mutation of the beta3-AR gene might affect obesity and HDL metabolism in obese boys. In contrast, C161T mutation of the PPARgamma gene, by itself, is unlikely to influence obesity, lipid metabolism or plasma leptin levels.