Role of androgen receptor CAG repeat polymorphism in pathogenesis of coronary artery disease in elderly men / 中华老年医学杂志

ABSTRACT

Objective To investigate the relationship of androgen receptor (AR) CAG repeat polymorphism and coronary artery disease (CAD) in elderly men and its potential mechanism.Methods Totally 296 elderly men undergoing coronary angiography were enrolled in this study.Serum total testosterone (TT) and free testosterone (FT) levels were measured.Androgen receptors (ARs) in peripheral lymphocytes were determined by flow cytometry.Genome DNA was extracted from peripheral leucocytes using standard techniques.Gene fragments containing AR CAG repeats were amplified by PCR with specific fluorescent labeled primers.PCR products were separated with agarose gels.CAG repeat number of each sample was obtained by genotyping.Results AR CAG repeats varied from 11 to 28 (P25-P75:18-22; median:20) in elderly male patients.They were divided into the long AR group (CAG repeats≥22,n=82) and the short AR group (CAG repeats＜22,n=214).Compared with the long AR group,serum FT level was much lower in the short AR group [(24.1±23.1) ×10-6mmol/L vs.(31.2±27.8)×10-6mmol/L,P＜0.05].The prevalence of coronary artery disease was higher in the short AR group than in the long AR group [84.1％ (180 cases) vs.69.5％(57 cases),P＜0.05].The FT level was lower in the short AR group combined with CAD than in the control group [(22.4±20.5) ×10-6mmol/L vs.(33.6±32.4)×10 6mmol/L,P＜0.01].There were no significant differences in serum TT and AR levels between the long and short AR groups.No significant correlations were found in the AR CAG repeats polymorphism with FT,TT or AR levels.Age was the main risk factor for FT and AR levels.Logistic regression analysis showed that FT level was negatively correlated with CAD (OR=0.98,95 ％ CI:0.973-0.998,P=0.01),and short AR increased the risk of CAD in elderly male patients (OR=3.44,95％CI:1.887-6.264,P＜0.01).Conclusions Serum FT level is correlated with age and is significantly decreased in elderly male patients with short AR repeats,which may increase the risk of CAD in elderly men.