Beta(2)-adrenergic receptor gene polymorphism, age, and cardiovascular phenotypes

Area of Science:

• Cardiovascular Genetics
• Pharmacogenomics
• Metabolic Research

Background:

• Beta(2)-adrenergic receptor (ADRB2) variants are hypothesized to modulate cardiovascular and metabolic phenotypes.
• Previous research suggests differential functional responses to adrenergic stimulation based on ADRB2 genotypes.

Purpose of the Study:

• To investigate the association of ADRB2 G/R16 and Q/E27 polymorphisms and their haplotypes with blood pressure, cardiac structure/function, and metabolic risk factors in a general population.
• To determine if ADRB2 variants influence cardiovascular and metabolic traits, particularly in relation to age.

Main Methods:

• Analysis of a random population sample (n=571, ages 35-64).
• Genotyping for ADRB2 G/R16 and Q/E27 polymorphisms and haplotype analysis.
• Assessment of clinic and 24-hour ambulatory blood pressure, cardiac structure and function, and metabolic parameters (BMI, glycemia, triglyceridemia).

Main Results:

• No significant association between ADRB2 genotypes and blood pressure or cardiac parameters in the overall population.
• The R16 allele was associated with higher systolic blood pressure in younger individuals (<50 years).
• The R16-Q27 haplotype was linked to higher blood pressure, lower heart rate, higher BMI, lower glycemia, and higher triglyceridemia in younger subjects.

Conclusions:

• ADRB2 gene variability does not appear to play a major role in overall blood pressure modulation.
• Cardiovascular and metabolic associations of ADRB2 polymorphism are more evident in younger individuals, potentially masked by age-related decline in ADRB2 signaling.
• Aging-related changes in ADRB2 function must be considered when evaluating the phenotypic effects of genetic variants.