Symptom severity impacts sympathetic dysregulation and inflammation in post-traumatic stress disorder (PTSD)

• Type of Material: Article
• Authors: Ida Fonkoue, Emory University; Paul J. Marvar, George Washington University; Seth Norrholm, Emory University; Yunxiao Li, Emory University; Melanie L. Kankam, Emory University; Toure N. Jones, Emory University; Monica Vemulapalli, Emory University; Barbara Rothbaum, Emory University; James Bremner, Emory University; Ngoc-Anh Le, Atlanta Veterans Affairs Health Care System; Jeanie Park, Emory University
• Language: English
• Date: 2020-01-01
• Publisher: ACADEMIC PRESS INC ELSEVIER SCIENCE
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: 2019
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.bbi.2019.10.021
• Title of Journal or Parent Work: BRAIN BEHAVIOR AND IMMUNITY
• Volume: 83
• Start Page: 260
• End Page: 269
• Grant/Funding Information: This work was supported by Merit Review Award number I01CX001065 from the United States Department of Veterans Affairs (VA) Clinical Sciences Research and Development Program; American Heart Association National Affiliate, Collaborative Sciences Award 15CSA24340001; National Institutes of Health (NIH) R01 HL135183; NIH training grant T32 DK-00756; Department of Veterans Affairs, Veterans Health Administration, Office of Research and Development and the Clinical Studies Center of the Atlanta VA Health Care System, Decatur, Georgia; and Foundation for Atlanta Veterans Education and Research (FAVER).
• Keywords: PTSD severity; BLOOD; HEART-RATE-VARIABILITY; Blood pressure; RISK-FACTORS; NERVE ACTIVITY; Psychiatry; VETERANS; BAROREFLEX SENSITIVITY; MORTALITY; Life Sciences & Biomedicine; Autonomic activity; Neurosciences; MENTAL STRESS; Inflammation; CARDIOVASCULAR-DISEASE METAANALYSIS; Baroreflex sensitivity; Neurosciences & Neurology; RESPONSES; Science & Technology; Immunology
• Research Categories: Health Sciences, Immunology; Biology, Neuroscience; Psychology, Clinical

Abstract

Post-traumatic stress disorder (PTSD) is associated with a greater risk of incident hypertension and cardiovascular disease. Inflammation, impaired baroreflex sensitivity (BRS) decreased parasympathetic nervous system (PNS) and overactive sympathetic nervous system (SNS) activity are suggested as contributing mechanisms. Increasing severity of PTSD symptoms has been linked to greater cardiovascular risk; however, the impact of PTSD symptom severity on inflammation and autonomic control of blood pressure has not yet been explored. We hypothesized that increasing PTSD symptom severity is linked to higher inflammation, greater SNS activity, lower PNS reactivity and impaired BRS. Seventy Veterans participated in this study: 28 with severe PTSD ((Clinical Administered PTSD Scale (CAPS) > 60; S-PTSD), 16 with moderate PTSD (CAPS ≥ 45 ≤ 60; M-PTSD) and 26 Controls (CAPS < 45; NO-PTSD). We recorded continuous blood pressure (BP), heart rate (HR) via EKG, heart rate variability (HRV) markers reflecting PNS and muscle sympathetic nerve activity (MSNA) at rest, during arterial baroreflex sensitivity (BRS) testing via the modified Oxford technique, and during 3 min of mental stress via mental arithmetic. Blood samples were analyzed for 12 biomarkers of systemic and vascular inflammation. While BP was comparable between severity groups, HR tended to be higher (p = 0.055) in S-PTSD (76 ± 2 beats/min) than in Controls (67 ± 2 beats/min) but comparable to M-PTSD (70 ± 3 beats/min). There were no differences in resting HRV and MSNA between groups; however, cardiovagal BRS was blunted (p = 0.021) in S-PTSD (10 ± 1 ms/mmHg) compared to controls (16 ± 3 ms/mmHg) but comparable to M-PTSD (12 ± 2 ms/mmHg). Veterans in the S-PTSD group had a higher (p < 0.001) combined inflammatory score compared to both M-PTSD and NO-PTSD. Likewise, while mental stress induced similar SNS and cardiovascular responses between the groups, there was a greater reduction in HRV in S-PTSD compared to both M-PTSD and NO-PTSD. In summary, individuals with severe PTSD symptoms have higher inflammation, greater impairment of BRS, a trend towards higher resting HR and exaggerated PNS withdrawal at the onset of mental stress that may contribute to cardiovascular risk in severe PTSD.