Autonomic dysfunction and cardiovascular risk in post-traumatic stress disorder

Exaggerated Peripheral and Systemic Vasoconstriction During Trauma Recall in Posttraumatic Stress Disorder: A Co-Twin Control Study

BACKGROUND

Individuals with posttraumatic stress disorder (PTSD) face an increased risk of cardiovascular disease, but the mechanisms linking PTSD to cardiovascular disease remain incompletely understood. We used a co-twin control study design to test the hypothesis that individuals with PTSD exhibit augmented peripheral and systemic vasoconstriction during a personalized trauma recall task.

METHODS

In 179 older male twins from the Vietnam Era Twin Registry, lifetime history of PTSD and current (last month) PTSD symptoms were assessed. Participants listened to neutral and personalized trauma scripts while peripheral vascular tone (Peripheral Arterial Tone ratio) and systemic vascular tone (e.g., total vascular conductance) were measured. Linear mixed-effect models were used to assess the within-pair relationship between PTSD and vascular tone indices.

RESULTS

The mean age of participants was 68 years, and 19% had a history of PTSD. For the Peripheral Arterial Tone ratio analysis, 32 twins were discordant for a history of PTSD, and 46 were discordant for current PTSD symptoms. Compared with their brothers without PTSD, during trauma recall, participants with a history of PTSD had greater increases in peripheral (β = -1.01, 95% CI [-1.72, -0.30]) and systemic (total vascular conductance: β = -1.12, 95% CI [-1.97, -0.27]) vasoconstriction after adjusting for cardiovascular risk factors. Associations persisted after adjusting for antidepressant medication use and heart rate and blood pressure during the tasks. Analysis of current PTSD symptom severity showed consistent results.

CONCLUSIONS

PTSD is associated with exaggerated peripheral and systemic vasoconstrictor responses to traumatic stress reminders, which may contribute to elevated risk of cardiovascular disease.

New recognition of the heart-brain axis and its implication in the pathogenesis and treatment of PTSD

Post-traumatic stress disorder (PTSD) is a complex psychological disorder provoked by distressing experiences, and it remains without highly effective intervention strategies. The exploration of PTSD's underlying mechanisms is crucial for advancing diagnostic and therapeutic approaches. Current studies primarily explore PTSD through the lens of the central nervous system, investigating concrete molecular alterations in the cerebral area and neural circuit irregularities. However, the body's response to external stressors, particularly the changes in cardiovascular function, is often pronounced, evidenced by notable cardiac dysfunction. Consequently, examining PTSD with a focus on cardiac function is vital for the early prevention and targeted management of the disorder. This review undertakes a comprehensive literature analysis to detail the alterations in brain and heart structures and functions associated with PTSD. It also synthesizes potential mechanisms of heart-brain axis interactions relevant to the development of PTSD. Ultimately, by considering cardiac function, this review proposes novel perspectives for PTSD's prophylaxis and therapy.

Beyond Confirmed Mast Cell Activation Syndrome: Approaching Patients With Dysautonomia and Related Conditions

Allergist-immunologists face significant challenges as experts in an ever-evolving field of neuroimmunology. Among these challenges is the increasingly frequent need to counsel patients with suspected mast cell activation disorders about perceived comorbidities, which may include hypermobile Ehlers-Danlos syndrome, amplified pain syndrome, fibromyalgia, burning sensation syndromes, migraines, irritable bowel syndrome, and postural orthostatic tachycardia syndrome. Patients may experience comorbid anxiety, panic disorder, and depression associated with disturbed sleep, fatigue, and cognitive impairment that often worsen when their physical symptoms increase in severity. These conditions may mimic mast cell activation disorders and are emotionally taxing for patients and clinicians because they are often accompanied by vague diagnostic courses, perceived unmanageability, social stigma, and significant impairment in quality of life. Combined with relatively poorly researched therapies, it is no surprise that clinicians may feel overwhelmed or find it difficult to provide consistently compassionate care for this population. In this article, we review available therapies for these conditions, which run the gamut from physical therapy to antidepressants to multimodal pain control. We highlight the benefit of multidisciplinary care within the primary care home, which includes an important role by the allergist-immunologist. By outlining simple approaches to initial treatment, we hope to empower clinicians with the tools needed to curb emotional burnout and embrace this patient population with compassion.

Validity of mental and physical stress models

Different stress models are employed to enhance our understanding of the underlying mechanisms and explore potential interventions. However, the utility of these models remains a critical concern, as their validities may be limited by the complexity of stress processes. Literature review revealed that both mental and physical stress models possess reasonable construct and criterion validities, respectively reflected in psychometrically assessed stress ratings and in activation of the sympathoadrenal system and the hypothalamic-pituitary-adrenal axis. The findings are less robust, though, in the pharmacological perturbations' domain, including such agents as adenosine or dobutamine. Likewise, stress models' convergent- and discriminant validity vary depending on the stressors' nature. Stress models share similarities, but also have important differences regarding their validities. Specific traits defined by the nature of the stressor stimulus should be taken into consideration when selecting stress models. Doing so can personalize prevention and treatment of stress-related antecedents, its acute processing, and chronic sequelae. Further work is warranted to refine stress models' validity and customize them so they commensurate diverse populations and circumstances.

Higher arterial stiffness and blunted vagal control of the heart in young women with compared to without a clinical diagnosis of PTSD

PURPOSE

Young women are typically thought to be protected from cardiovascular disease (CVD) before menopause. However, posttraumatic stress disorder (PTSD) increases CVD risk in women by up to threefold. Data in predominantly male cohorts point to physiological mechanisms such as vascular and autonomic derangements as contributing to increased CVD risk. The purpose of the study reported here was to determine whether young women diagnosed with PTSD, compared to those without, present with arterial stiffness and impaired autonomic control of the heart.

METHODS

A total of 73 healthy young women, ranging in age from 18 to 40 years, with a history of trauma exposure were included in this study, 32 with and 41 without a clinical PTSD diagnosis. We measured resting pulse wave velocity (PWV), central hemodynamics, augmentation pressure and augmentation index (AI) via pulse wave analysis using applanation tonometry. Heart rate variability was also assessed via peripheral arterial tone.

RESULTS

In comparison to controls, women with PTSD showed higher central arterial pressure (mean ± standard deviation: systolic blood pressure 104 ± 8 vs. 97 ± 8 mmHg, p < 0.001; diastolic blood pressure 72 ± 7 vs. 67 ± 7 mmHg, p = 0.003), PWV (6 ± 0.3 vs. 5 ± 0.6 m/s, p < 0.001) and AI (22 ± 13 vs. 15 ± 12%, p = 0.007) but lower standard deviation of normal-to-normal intervals (SDNN; 44 ± 17 vs. 54 ± 18 ms, p = 0.005) and root mean square of successive differences between normal heartbeats (RMSSD; 37 ± 17 vs. 51 ± 22 ms, p = 0.002).

CONCLUSION

PTSD in young women is associated with higher brachial and central pressures, increased arterial stiffness and blunted parasympathetic control of the heart. These findings illustrate potential mechanisms underlying high risk for CVD in young women with PTSD, suggesting possible treatment targets for this at-risk group.

Attenuated peripheral oxygen extraction and greater cardiac output in women with posttraumatic stress disorder during exercise

Posttraumatic stress disorder (PTSD) is associated with an increased risk of developing cardiovascular disease, especially in women. Evidence indicates that men with PTSD exhibit lower maximal oxygen uptake (V̇o2max) relative to controls; however, whether V̇o2max is blunted in women with PTSD remains unknown. Furthermore, it is unclear what determinants (i.e., central and/or peripheral) of V̇o2max are impacted by PTSD. Therefore, we evaluated the central (i.e., cardiac output; Q̇c) and peripheral (i.e., arteriovenous oxygen difference) determinants of V̇o2max in women with PTSD; hypothesizing that V̇o2max would be lower in women with PTSD compared with women without PTSD (controls), primarily due to smaller increases in stroke volume (SV), and therefore Q̇c. Oxygen uptake (V̇o2), heart rate (HR), Q̇c, SV, and arteriovenous oxygen difference were measured in women with PTSD (n = 14; mean [SD]: 43 [11] yr,) and controls (n = 17; 45 [11] yr) at rest, and during an incremental maximal treadmill exercise test, and the Q̇c/V̇o2 slope was calculated. V̇o2max was not different between women with and without PTSD (24.3 [5.6] vs. 26.4 [5.0] mL/kg/min; P = 0.265). However, women with PTSD had higher Q̇c [P = 0.002; primarily due to greater SV (P = 0.069), not HR (P = 0.285)], and lower arteriovenous oxygen difference (P = 0.002) throughout exercise compared with controls. Furthermore, the Q̇c/V̇o2 slope was steeper in women with PTSD relative to controls (6.6 [1.4] vs. 5.7 [1.0] AU; P = 0.033). Following maximal exercise, women with PTSD exhibited slower HR recovery than controls (P = 0.046). Thus, despite attenuated peripheral oxygen extraction, V̇o2max is not reduced in women with PTSD, likely due to larger increases in Q̇c.NEW & NOTEWORTHY The current study indicates that V̇o2max is not different between women with and without PTSD; however, women with PTSD exhibit blunted peripheral extraction of oxygen, thus requiring an increase in Q̇c to meet metabolic demand during exercise. Furthermore, following exercise, women with PTSD demonstrate impaired autonomic cardiovascular control relative to sedentary controls. We interpret these data to indicate that women with PTSD demonstrate aberrant cardiovascular responses during and immediately following fatiguing exercise.

A 4-session written emotional disclosure intervention lowers 6-month sympathoadrenal urinary output in persons living with HIV

OBJECTIVE

We previously reported that a brief guided written emotional disclosure (WED) intervention resulted in significant reductions in post-traumatic stress disorder (PTSD) symptomology in women, but not men, living with HIV. Levels of 24-hour urinary output of epinephrine (E) and norepinephrine (NE) are shown to be elevated in persons diagnosed with PTSD. The current study tested whether there was an effect for the 4-week WED intervention on 6-month change in urinary E and NE output amongst persons living with HIV.

METHOD

Fourteen women and 11 men living with HIV randomized to four 30-min expressive writing sessions of either trauma writing or daily events writing in the parent trial were included based upon collection of urine specimens at baseline, 1-, and 6-months after the intervention. Total volume (µg) and concentration (µg/ml) of urinary E and NE were derived from the specimens as study outcomes.

RESULTS

Four repeated measures analyses of covariance (ANCOVA) were performed to evaluate study outcomes using trauma- versus daily-writing as the between-subject factors and collection time point as the within-subject factor, controlling for age and sex. A group x time interaction was observed wherein the trauma writing treatment group showed a significantly greater decrease in total urinary output, F(2, 46) = 4.03, p = .03, and concentration, F(2, 46) = 4.74, p = .01 of epinepherine. Post-hoc analyses revealed the interaction effect for the total, F(2, 22) = 4.82, p = .03, and concentration, F(2, 22) = 7.57, p = .005, of urinary E output over 6-months was significant for women. Interactions were not observed in urinary NE output.

CONCLUSIONS

Significant reductions in the total output and concentration of urinary E were found up to 6-months following initiation of a 4-session guided written emotional disclosure intervention. Profiles of sympathoadrenal activity and response to expressive writing differ between men and women living with HIV. Futher research is need to characterize the putative pathways linking sympathoadrenal response to upstream neurobiological function and downstream inflammatory-immune status in women living with HIV and PTSD.

Posttraumatic stress disorder, diurnal cortisol, and ambulatory blood pressure in early and late pregnancy

Posttraumatic stress disorder (PTSD) affects 1 in 20 reproductive-aged women and is associated with cardiovascular disease morbidity and mortality. The pathophysiology linking PTSD to cardiovascular disease in nonpregnant adults is proposed to include hypothalamic and autonomic dysregulation; however, the pathways explaining this association in pregnancy are unclear. We examined diurnal cortisol and ambulatory blood pressure (BP) among 254 pregnant women at approximately 12 and 32 gestational weeks. Participants were, on average, 31 years old (SD = 5), 24.4% reported their ethnicity as Hispanic, and 62.2% reported their race as White. PTSD symptoms were measured using the PTSD Checklist for DSM-5 (PCL-5). Hierarchical linear regression analyses were performed to examine associations pregnancy between PTSD and cortisol at awakening, 30 min after awakening, and bedtime in early and late pregnancy, as well as associations between PTSD symptoms and daytime and nighttime systolic (SBP) and diastolic BP (DBP) and BP variability. Logistic regression analyses were conducted to test associations between PTSD symptoms and BP dipping. The results showed a positive association between PTSD symptoms and nighttime BP and BP variability at 32 gestational weeks, ∆R2 = .036-.067. PTSD symptoms were negatively associated with awakening cortisol at 12 gestational weeks in unadjusted models. These findings contribute to understanding the associations between PTSD and adverse cardiovascular conditions in pregnancy. More research is needed to replicate these findings and examine whether PTSD interventions are effective at modifying pathways and decreasing the risk for cardiovascular complications in pregnancy.

Physiological regulation of leptin as an integrative signal of reproductive readiness

Reproductive function is tightly regulated by both environmental and physiological factors. The adipose-derived hormone leptin has been identified as one such critical factor that relays information about peripheral energy availability to the centrally-governed HPG axis to ensure there is sufficient energy availability to support the high energy demands of mammalian reproduction. In the absence of adequate central leptin signaling, reproductive function is suppressed. While leptin levels are predominantly regulated by adiposity, circulating leptin levels are also under the modulatory influence of other factors, such as stress system activation, circadian rhythmicity, and immune activation and the inflammatory response. Furthermore, changes in leptin sensitivity can affect the degree to which leptin exerts its influence on the neuroendocrine reproductive axis. This review will discuss the different mechanisms by which leptin serves to integrate and relay information about metabolic, psychological, environmental and immune conditions to the central neuronal network that governs reproductive function.

Understanding the comorbidity between posttraumatic stress severity and coronary artery disease using genome-wide information and electronic health records

The association between coronary artery disease (CAD) and posttraumatic stress disorder (PTSD) contributes to the high morbidity and mortality observed for these conditions. To understand the dynamics underlying PTSD-CAD comorbidity, we investigated large-scale genome-wide association (GWA) statistics from the Million Veteran Program (MVP), the UK Biobank (UKB), the Psychiatric Genomics Consortium, and the CARDIoGRAMplusC4D Consortium. We observed a genetic correlation of CAD with PTSD case-control and quantitative outcomes, ranging from 0.18 to 0.32. To investigate possible cause-effect relationships underlying these genetic correlations, we performed a two-sample Mendelian randomization (MR) analysis, observing a significant bidirectional relationship between CAD and PTSD symptom severity. Genetically-determined PCL-17 (PTSD 17-item Checklist) total score was associated with increased CAD risk (odds ratio = 1.04; 95% confidence interval, 95% CI = 1.01-1.06). Conversely, CAD genetic liability was associated with reduced PCL-17 total score (beta = -0.42; 95% CI = -0.04 to -0.81). Because of these opposite-direction associations, we conducted a pleiotropic meta-analysis to investigate loci with concordant vs. discordant effects on PCL-17 and CAD, observing that concordant-effect loci were enriched for molecular pathways related to platelet amyloid precursor protein (beta = 1.53, p = 2.97 × 10-7) and astrocyte activation regulation (beta = 1.51, p = 2.48 × 10-6) while discordant-effect loci were enriched for biological processes related to lipid metabolism (e.g., triglyceride-rich lipoprotein particle clearance, beta = 2.32, p = 1.61 × 10-10). To follow up these results, we leveraged MVP and UKB electronic health records (EHR) to assess longitudinal changes in the association between CAD and posttraumatic stress severity. This EHR-based analysis highlighted that earlier CAD diagnosis is associated with increased PCL-total score later in life, while lower PCL total score was associated with increased risk of a later CAD diagnosis (Mann-Kendall trend test: MVP tau = 0.932, p < 2 × 10-16; UKB tau = 0.376, p = 0.005). In conclusion, both our genetically-informed analyses and our EHR-based follow-up investigation highlighted a bidirectional relationship between PTSD and CAD where multiple pleiotropic mechanisms are likely to be involved.

Know thy SEFL: Fear sensitization and its relevance to stressor-related disorders

Extreme stress can cause long-lasting changes in affective behavior manifesting in conditions such as post-traumatic stress disorder (PTSD). Understanding the biological mechanisms that govern trauma-induced behavioral dysregulation requires reliable and rigorous pre-clinical models that recapitulate multiple facets of this complex disease. For decades, Pavlovian fear conditioning has been a dominant paradigm for studying the effects of trauma through an associative learning framework. However, severe stress also causes long-lasting nonassociative fear sensitization, which is often overlooked in Pavlovian fear conditioning studies. This paper synthesizes recent research on the stress-enhanced fear learning (SEFL) paradigm, a valuable rodent model that can dissociate associative and nonassociative effects of stress. We discuss evidence that the SEFL paradigm produces nonassociative fear sensitization that is distinguishable from Pavlovian fear conditioning. We also discuss key biological variables, such as age and sex, neural circuit mechanisms, and crucial gaps in knowledge. We argue that nonassociative fear sensitization deserves more attention within current PTSD models and that SEFL provides a valuable complement to Pavlovian conditioning research on trauma-related pathology.