Impact of acute antioxidant supplementation on vascular function and autonomic nervous system modulation in young adults with PTSD

Abstract

Posttraumatic stress disorder (PTSD) has been associated with an increase in risk of cardiovascular disease (CVD). The goal of this study was to determine if peripheral vascular dysfunction, a precursor to CVD, was present in young adults with PTSD, and if an acute antioxidant (AO) supplementation could modify this potential PTSD-induced vascular dysfunction. Thirteen individuals with PTSD were recruited for this investigation and were compared with 35 age- and sex-matched controls (CTRL). The PTSD group participated in two visits, consuming either a placebo (PTSD-PL) or antioxidants (PTSD-AO; vitamins C and E; α-lipoic acid) before their visits, whereas the CTRL subjects only participated in one visit. Upper and lower limb vascular functions were assessed via flow-mediated dilation and passive leg movement technique. Heart rate variability was utilized to assess autonomic nervous system modulation. The PTSD-PL condition, when compared with the CTRL group, reported lower arm and leg microvascular function as well as sympathetic nervous system (SNS) predominance. After acute AO supplementation, arm, but not leg, microvascular function was improved and SNS predominance was lowered to which the prior difference between PTSD group and CTRL was no longer significant. Young individuals with PTSD demonstrated lower arm and leg microvascular function as well as greater SNS predominance when compared with age- and sex-matched controls. Furthermore, this lower vascular/autonomic function was augmented by an acute AO supplementation to the level of the healthy controls, potentially implicating oxidative stress as a contributor to this blunted vascular/autonomic function.

Keywords: PTSD; antioxidant; autonomic nervous system; posttraumatic stress disorder; vascular function.

Figure 1.

Study schematic. AO, antioxidants; BP, blood pressure; FMD, flow-mediated dilation; HR, heart rate; HRV, heart rate variability; PL, placebo; PLM, passive leg movement.

Figure 2.

High-frequency (HF) power (A), low-frequency (LF) power (B), and low frequency-to-high frequency ratio (LF/HF) (C) for control subjects (CTRL, n = 19; 13 females/6 males) and subjects with posttraumatic stress disorder (PTSD) during the placebo (PTSD-PL; n = 10; 8 females/2 males) and antioxidant (PTSD-AO; n = 10; 8 females/2 males) condition. *Significantly different from PTSD-PL group. #Significantly different from CTRL and PTSD-AO group. Data were analyzed with both independent (CTRL vs. PTSD-PL; CTRL vs. PTSD-AO) and paired (PTSD-PL vs. PTSD-AO) samples t tests and is represented as means ± SD as well as individual data points (female participants = white circles; male participants = black circles).

Figure 3.

Brachial artery flow-mediated dilation (BA FMD) (A) and BA blood flow area under the curve (AUC) (B) for control subjects (CTRL, n = 23; 16 females/7 males) and subjects with posttraumatic stress disorder (PTSD) during the placebo (PL; n = 13; 9 females/4 males) and antioxidant (AO; n = 13; 9 females/4 males) condition. *Significantly different from CTRL group. Data were analyzed with both independent (CTRL vs. PTSD-PL; CTRL vs. PTSD-AO) and paired (PTSD-PL vs. PTSD-AO) samples t tests and is represented as means ± SD as well as individual data points (female participants = white circles; male participants = black circles).

Figure 4.

Superficial femoral artery (SFA) flow-mediated dilation (FMD) (A) and SFA blood flow area under the curve (AUC) (B) for control subjects (CTRL, n = 23; 16 females/7 males) and subjects with posttraumatic stress disorder (PTSD) during the placebo (PL; n = 13; 9 females/4 males) and antioxidant (AO; n = 13; 9 females/4 males) condition. Peak change from baseline in passive leg movement-induced blood flow (LBF_Δpeak) (C) for control subjects (CTRL, n = 21; 15 females/6 males) and subjects with PTSD during the placebo (PL; n = 13; 9 females/4 males) and antioxidant (AO; n = 13; 9 females/4 males) condition. *Significantly different from CTRL group. Data were analyzed with both independent (CTRL vs. PTSD-PL; CTRL vs. PTSD-AO) and paired (PTSD-PL vs. PTSD-AO) samples t tests and is represented as means ± SD as well as individual data points (female participants = white circles; male participants = black circles).