Lymphocyte DNA damage and total antioxidant status in patients with white-coat hypertension and sustained hypertension

Objectives: We assessed lymphocyte DNA damage andtotal antioxidant status (TAS) in patients with white-coat hypertension (WCH) and sustained hypertension (SHT). Study design: The study included 23 patients (14 females, 9 males; mean age 46 +/- 6 years) with WCH, 21 patients (13 females, 8 males; mean age 45 +/- 7 years) with newly diagnosed SHT, and 19 age-and sex-matched healthy volunteers as controls. All subjects underwent echocardiographic examination, office blood pressure measurements, and 24-hour ambulatory blood pressure monitoring. DNA damage was assessed by the alkaline comet assay in peripheral lymphocytes, and plasma TAS levels were determined using an automated measurement method. Results: The two hypertensive groups had similar echocardiographic measurements and office systolic and diastolic blood pressures. The mean daytime and nighttime pressures were significantly higher in the SHT group (p< 0.05). Patients with WCH had similar daytime and nighttime pressures compared to the controls (p> 0.05). Patients with SHT had significantly increased lymphocyte DNA damage (p< 0.001, for both WCH and control groups) and decreased TAS level ( p= 0.012 vs WCH group; p< 0.001 vs controls). Patients with WCH did not differ significantly from the control group with regard to lymphocyte DNA damage (p= 0.052), but had significantly lower TAS levels (p< 0.001). In the SHT group, lymphocyte DNA damage was correlated with TAS (r= - 0.818, p< 0.001), age (r= 0.453, p= 0.039), total cholesterol (r= 0.550, p= 0.010), and LDL-cholesterol (r= 0.539, p= 0.012). In multiple linear regression analysis, lymphocyte DNA damage was independently correlated with serum TAS level (beta= - 0.717, p< 0.001). In the WCH group, lymphocyte DNA damage was only correlated with serum TAS level (r= - 0.458, p= 0.028). Conclusion: Decreased TAS showing increased oxidative stress and increased lymphocyte DNA damage may contribute to target organ damage in patients with WCH.