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

Abstract

PURPOSE: Posttraumatic stress disorder (PTSD) has been associated with an increase in risk of cardiovascular disease (CVD). The goal of the 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. METHODS: Thirteen individuals with PTSD were recruited for this investigation and were compared to 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; Alpha Lipoic Acid) prior to their visits, while the CRTL subjects only participated in one visit. Upper and lower limb vascular function were assessed via flow-mediated dilation and passive leg movement technique. Heart rate variability was utilized to assess autonomic nervous system modulation. RESULTS: The PTSD-PL condition, when compared to the CTRL group, reported lower arm and leg microvascular function as well as sympathetic nervous system (SNS) predominance. Following 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. CONCLUSION: Young individuals with PTSD demonstrated lower arm and leg microvascular function as well as greater SNS predominance when compared to 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.

Lower vascular conductance responses to handgrip exercise are improved following acute antioxidant supplementation in young individuals with post‐traumatic stress disorder

“…Thirteen young, otherwise healthy adults with PTSD (nine female, four male) and 13 sex‐ and age‐matched healthy controls were recruited from Virginia Commonwealth University and the Richmond, Virginia metropolitan area to participate in this study. The PTSD group comprised the same participants who participated in a recently published study that identified microvascular dysfunction and SNS predominance at rest in this population (vs. healthy controls) (Weggen et al., 2021). Apart from subject demographics, no other data have been previously published.…”

“…Prior work by our laboratory identified microvascular dysfunction in the arm and leg as well as autonomic nervous system imbalance in young (∼23 years) individuals with PTSD (Weggen et al, 2021), but as these measures were employed at rest it is unclear if these consequences of PTSD are robust enough to impact blood flow regulation during exercise, a hallmark characteristic of future hypertension and CVD development (Jae et al, 2015;Yang et al, 2014).…”

“…Recent work has revealed elevated SNS activation/transduction in response to isometric exercise in middle-aged individuals with PTSD (D'Souza et al, 2022) vascular function and autonomic nervous system balance at rest in young individuals with PTSD to that of well-matched controls (Weggen et al, 2021), potentially implicating the consequences of redox imbalance as a mediator of this dysfunction. Indeed, redox imbalance, or the state to which oxidant production overwhelms the exogenous and endogenous antioxidant defence within the body, has been implicated as a major by-product of the psychological symptoms of PTSD (Hori & Kim, 2019;Miller & Sadeh, 2014) and as a mediator of peripheral vascular dysfunction (Greaney et al, 2019;Wray et al, 2017) and SNS overactivation (Grotle & Stone, 2019).…”

“…Dysregulation of skeletal muscle blood flow can result from local dysfunction of the microvasculature due to an imbalance in dilatory and constrictor vasoactive substances, and/or elevated sympathetic nervous system (SNS) activation/transduction, all of which can result in excessive vasoconstriction within the working muscle (Mitchell, 2017). Prior work by our laboratory identified microvascular dysfunction in the arm and leg as well as autonomic nervous system imbalance in young (∼23 years) individuals with PTSD (Weggen et al., 2021), but as these measures were employed at rest it is unclear if these consequences of PTSD are robust enough to impact blood flow regulation during exercise, a hallmark characteristic of future hypertension and CVD development (Jae et al., 2015; Yang et al., 2014). Recent work has revealed elevated SNS activation/transduction in response to isometric exercise in middle‐aged individuals with PTSD (D'Souza et al., 2022), highlighting abnormal peripherally mediated mean arterial pressure (MAP) responses to exercise, but it is unknown if this response is present in young individuals or if this abnormal response is present during exercise with a distinct contraction–relaxation pattern (e.g., isotonic), which more directly translates to normal and/or occupational activities of daily living.…”

“…Recent work has revealed elevated SNS activation/transduction in response to isometric exercise in middle‐aged individuals with PTSD (D'Souza et al., 2022), highlighting abnormal peripherally mediated mean arterial pressure (MAP) responses to exercise, but it is unknown if this response is present in young individuals or if this abnormal response is present during exercise with a distinct contraction–relaxation pattern (e.g., isotonic), which more directly translates to normal and/or occupational activities of daily living. Of interest, an acute antioxidant supplementation restored both upper limb microvascular function and autonomic nervous system balance at rest in young individuals with PTSD to that of well‐matched controls (Weggen et al., 2021), potentially implicating the consequences of redox imbalance as a mediator of this dysfunction. Indeed, redox imbalance, or the state to which oxidant production overwhelms the exogenous and endogenous antioxidant defence within the body, has been implicated as a major by‐product of the psychological symptoms of PTSD (Hori & Kim, 2019; Miller & Sadeh, 2014) and as a mediator of peripheral vascular dysfunction (Greaney et al., 2019; Wray et al., 2017) and SNS overactivation (Grotle & Stone, 2019).…”