Association of serum aryl hydrocarbon receptor activity and RBC omega-3 polyunsaturated fatty acids with flow-mediated dilation in healthy, young Hispanic cigarette smokers.

Impaired flow-mediated dilation (FMD) occurs prior to clinical disease in young cigarette smokers. We investigated two potential biomarkers of FMD: serum aryl hydrocarbon receptor (AHR) activity and RBC omega-3 polyunsaturated fatty acids in healthy young Hispanic cigarette smokers. We recruited never (n=16) and current (n=16) Hispanic smokers (32 ± 7 years old), excluding individuals with clinical cardiovascular disease. We measured FMD with duplex ultrasound, RBC fatty acids and serum AHR activity using a luciferase reporter assay. FMD was significantly impaired in smokers (5.8 ± 4%) versus never smokers (12.3 ± 7.4%, p=0.001). Serum AHR activity was significantly increased in smokers (1467 ± 358 relative light units (RLU)) versus never smokers (689 ± 251 RLU, p<0.001), and correlated positively with FMD only in smokers (r=0.691, p<0.004). RBC percentage of α-linolenic acid (ALA%) was significantly increased in smokers (0.14 ± 0.03%) versus never smokers (0.11 ± 0.03%, p=0.018), and correlated inversely with FMD only in smokers (r=-0.538, p=0.03). The combination of serum AHR activity, ALA%, and systolic blood pressure significantly correlated with FMD in a multivariable regression model (r=0.802, p<0.008). These results suggest that serum AHR activity and RBC ALA% could serve as biomarkers of FMD in healthy, young Hispanic cigarette smokers.