Impaired Baroreflex Function during Rest and Graded Orthostasis in Women with PTSD

Abstract

Post‐traumatic stress disorder (PTSD) is more prevalent in women and associated with significantly higher risk of hypertension and cardiovascular disease. The underlying mechanisms are unclear, but impaired baroreflex function and vasomotor sympathetic neural control may be involved. We hypothesized that women with PTSD would have an impaired baroreflex control of muscle sympathetic nerve activity (MSNA). MSNA and hemodynamics were measured supine and during 30º and 60º head‐up tilt (HUT) in 14 women with PTSD and 14 healthy women (Controls). Sympathetic baroreflex sensitivity(BRS) was quantified using the slope of the linear correlation between MSNA and diastolic pressure during spontaneous breathing. Age and body mass index were not different between groups. Supine resting MSNA was greater in women with PTSD (PTSD vs. Controls: 27±3 vs. 14±3 bursts/min; P=0.002, mean±SEM). Sympathetic BRS was impaired in women with PTSD compared to controls in the supine position (PTSD vs. Controls: −43±7 vs. −64±9 units 100beats−1 mmHg−1, P=0.02). It remained lower in women with PTSD during 30º and 60º HUT (posturexgroup interaction P=0.1, time P=0.003, group P=0.03). MSNA response to the graded HUT was not different between groups but the efficacy of MSNA for vasoconstriction was greater in women with PTSD (HUT 30: 1.8±0.5 vs.0.9±0.4 %TPR/%totalMSNA; P=0.01, HUT60: 1.2±0.4 vs. 0.7±0.3; P=0.04). Our findings demonstrate that women with PTSD have decreased sympathetic BRS and it may contribute to augmented sympathetic activity. The higher efficacy of MSNA for vasoconstriction in PTSD suggests greater sympathetic vascular transduction and/or other nonadrenergic mechanisms responsible for vasoconstriction. These results may explain, in part, the underlying mechanisms for the greater risk of developing hypertension and cardiovascular disease in women with PTSD.Support or Funding InformationSupported by the Harry S. Moss Heart TrustThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.