The renin-angiotensin system in PTSD: a replication and extension

Use of renin-angiotensin system blockers and posttraumatic stress disorder risk in the UK Biobank: a retrospective cohort study

BACKGROUND

Previous research has shown that the use of renin-angiotensin system (RAS) blockers is linked to a lower prevalence of posttraumatic stress disorder (PTSD), but longitudinal studies are scarce. We aimed to estimate the association between the use of RAS blockers and the risk of PTSD among individuals taking antihypertensive medications.

METHODS

This longitudinal study included participants aged 40-69 from the UK Biobank. Exposure data were obtained from the initial assessment (2006-10), while outcome data were obtained from the online mental health questionnaire administered 6-11 years later (2016-17). We included participants who were under antihypertensive treatment and did not have a prior diagnosis of PTSD before the initial assessment. Use of RAS blockers was defined as self-reported regular use, at the initial assessment, of angiotensin-converting enzyme inhibitor (ACEi) or angiotensin receptor blocker (ARB). Among participants who experienced adverse life experiences, cases of probable PTSD were defined with the six-item PTSD Checklist-Civilian version score ≥ 14. Logistic regression with inverse probability of treatment weighting was used to estimate the odds ratios (ORs) and 95% confidence interval (CI) for the association between RAS blocker use and the risk of probable PTSD.

RESULTS

Of the 15,954 participants (mean age = 59.9 years; 42.6% women) under antihypertensive treatment with no prior history of PTSD at the initial assessment, 64.5% were taking RAS blockers. After a mean follow-up of 7.5 years, 1,249 (7.8%) were newly identified with probable PTSD. RAS blocker users had a lower risk of probable PTSD than RAS blocker non-users (OR = 0.84 [95% CI: 0.75-0.94]), whereas the use of other antihypertensive medications showed no such association (users vs. non-users; calcium channel blockers, OR = 0.99 [95% CI: 0.88-1.11]; beta-blockers, 1.20 [1.08-1.34]; and thiazide-related diuretics, 1.15 [1.03-1.29]). The association between probable PTSD risk and the use of ACEi vs. ARB showed no significant difference (p = 0.96).

CONCLUSIONS

Among individuals under antihypertensive treatment, the use of RAS blockers was associated with a decreased risk of probable PTSD. This added benefit of RAS blockers should be considered in the selection of antihypertensive medications.

Sex-Dependent Effects of Angiotensin Type 2 Receptor-Expressing Medial Prefrontal Cortex Interneurons in Fear Extinction Learning

Background

The renin-angiotensin system has been identified as a potential therapeutic target for posttraumatic stress disorder, although its mechanisms are not well understood. Brain angiotensin type 2 receptors (AT2Rs) are a subtype of angiotensin II receptors located in stress and anxiety-related regions, including the medial prefrontal cortex (mPFC), but their function and mechanism in the mPFC remain unexplored. Therefore, we used a combination of imaging, cre/lox, and behavioral methods to investigate mPFC-AT2R-expressing neurons in fear and stess related behavior.

Methods

To characterize mPFC-AT2R-expressing neurons in the mPFC, AT2R-Cre/tdTomato male and female mice were used for immunohistochemistry. mPFC brain sections were stained with glutamatergic or interneuron markers, and density of AT2R+ cells and colocalization with each marker were quantified. To assess fear-related behaviors in AT2R-flox mice, we selectively deleted AT2R from mPFC neurons using a Cre-expressing adeno-associated virus. Mice then underwent Pavlovian auditory fear conditioning, elevated plus maze, and open field testing.

Results

Immunohistochemistry results revealed that AT2R was densely expressed throughout the mPFC and primarily expressed in somatostatin interneurons in a sex-dependent manner. Following fear conditioning, mPFC-AT2R Cre-lox deletion impaired extinction and increased exploratory behavior in female but not male mice, while locomotion was unaltered by mPFC-AT2R deletion in both sexes.

Conclusions

These results identify mPFC-AT2R+ neurons as a novel subgroup of somatostatin interneurons and reveal their role in regulating fear learning in a sex-dependent manner, potentially offering insights into novel therapeutic targets for posttraumatic stress disorder.

Reduction of Aversive Learning Rates in Pavlovian Conditioning by Angiotensin II Antagonist Losartan: A Randomized Controlled Trial

BACKGROUND

Angiotensin receptor blockade has been linked to aspects of aversive learning and memory formation and to the prevention of posttraumatic stress disorder symptom development.

METHODS

We investigated the influence of the angiotensin receptor blocker losartan on aversive Pavlovian conditioning using a probabilistic learning paradigm. In a double-blind, randomized, placebo-controlled design, we tested 45 (18 female) healthy volunteers during a baseline session, after application of losartan or placebo (drug session), and during a follow-up session. During each session, participants engaged in a task in which they had to predict the probability of an electrical stimulation on every trial while the true shock contingencies switched repeatedly between phases of high and low shock threat. Computational reinforcement learning models were used to investigate learning dynamics.

RESULTS

Acute administration of losartan significantly reduced participants' adjustment during both low-to-high and high-to-low threat changes. This was driven by reduced aversive learning rates in the losartan group during the drug session compared with baseline. The 50-mg drug dose did not induce reduction of blood pressure or change in reaction times, ruling out a general reduction in attention and engagement. Decreased adjustment of aversive expectations was maintained at a follow-up session 24 hours later.

CONCLUSIONS

This study shows that losartan acutely reduces Pavlovian learning in aversive environments, thereby highlighting a potential role of the renin-angiotensin system in anxiety development.

Treatment Approaches for Posttraumatic Stress Disorder Derived From Basic Research on Fear Extinction

This brief review article will describe treatment approaches for posttraumatic stress disorder (PTSD) based on findings from basic research. The focus of this review will be fear conditioning and extinction models, which provide a translational model of PTSD that can help translate basic research in nonhuman animals through well-controlled trials confirming the efficacy of treatment approaches in humans with PTSD such as prolonged exposure therapy. Specific cognitive aspects of fear extinction processes, including consolidation and reconsolidation, are reviewed along with behavioral and pharmacological treatment strategies based on basic research in these areas including attempts to prevent the development of PTSD as well as the treatment of chronic PTSD. Pharmacological, behavioral, and device-based augmentation strategies of PTSD treatment based in basic science findings are reviewed, including those that disrupt noradrenergic receptor processes, medications that act on NMDA receptors, physical exercise, cannabinoids, estradiol, dexamethasone, yohimbine, losartan, dopamine, and MDMA, along with the evidence for their efficacy in human clinical samples. While fear extinction provides an exciting translational opportunity to improve PTSD based on basic science findings, we review limitations and challenges of the extant literature as well as future directions.

Effects of Evodiamine on Behavior and Hippocampal Neurons through Inhibition of Angiotensin-Converting Enzyme and Modulation of the Renin Angiotensin Pathway in a Mouse Model of Post-Traumatic Stress Disorder

Post-traumatic stress disorder (PTSD) is a persistent psychiatric condition that arises following exposure to traumatic events such as warfare, natural disasters, or other catastrophic incidents, typically characterized by heightened anxiety, depressive symptoms, and cognitive dysfunction. In this study, animals subjected to single prolonged stress (SPS) were administered evodiamine (EVO) and compared to a positive control group receiving sertraline. The animals were then assessed for alterations in anxiety, depression, and cognitive function. Histological analysis was conducted to examine neuronal changes in the hippocampus. In order to predict the core targets and related mechanisms of evodiamine intervention in PTSD, network pharmacology was used. The metabolic markers pre- and post-drug administration were identified using nontargeted serum metabolomics techniques, and the intersecting Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were screened. Finally, the core targets were validated through molecular docking, enzyme-linked immunosorbent assays, and immunofluorescence staining to confirm the anti-PTSD effects and mechanisms of these targets. As well as improving cognitive impairment, evodiamine reversed anxiety- and depression-like behaviors. It also inhibited the reduction in the number of hippocampal neuronal cells and Nissl bodies in SPS mice inhibited angiotensin converting enzyme (ACE) levels in the hippocampus of SPS mice, and modulated the renin angiotensin pathway and its associated serum metabolites in brain tissue. Evodiamine shows promise as a potential candidate for alleviating the symptoms of post-traumatic stress disorder.

Drug Repurposing and Personalized Treatment Strategies for Bipolar Disorder Using Transcriptomic

OBJECTIVE

The present study combined transcriptomic data and computational techniques based on gene expression signatures to identify novel bioactive compounds or FDA-approved drugs for the management of Bipolar Disorder (BD).

METHODS

Five transcriptomic datasets, comprising a total of 165 blood samples from BD case-control, were selected from the Gene Expression Omnibus repository (GEO). The number of subjects varied from 6 to 60, with a mean age ranging from 35 to 48, with a gender variation between them. Most of the patients were on pharmacological treatment. Master Regulator Analysis (MRA) and Gene Set Enrichment Analysis (GSEA) were performed to identify statistically significant genes between BD and HC and their association with the mood states of BD. Additionally, existing molecules with the potential to reverse the transcriptomic profiles of disease-altered regulons in BD were identified using the LINCS and cMap databases.

RESULTS

MRA identified 59 potential MRs candidates modulating the regulatory units enriched with genes altered in BD, while the GSEA identified 134 enriched genes, and a total of 982 regulons had their activation state determined. Both analyses showed genes exclusively associated with mania, depression, or euthymia, and some genes were common between the three mood states. We identified bioactive compounds and licensed drug candidates, including antihypertensives and antineoplastics, as promising candidates for treating BD. Nevertheless, experimental validation is essential to authenticate these findings in subsequent studies.

CONCLUSION

Although preliminary, our data provides some insights regarding the biological patterns of BD into distinct mood states and potential therapeutic targets. The combined transcriptomic and bioinformatics strategy offers a route to advance drug discovery and personalized medicine by tapping into gene expression information.

Acute Angiotensin II Receptor Blockade Facilitates Parahippocampal Processing During Memory Encoding in High-Trait-Anxious Individuals

Background

Angiotensin II receptor blockers (ARBs) have been associated with preventing posttraumatic stress disorder symptom development and improving memory. However, the underlying neural mechanisms are poorly understood. This study investigated ARB effects on memory encoding and hippocampal functioning that have previously been implicated in posttraumatic stress disorder development.

Methods

In a double-blind randomized design, 40 high-trait-anxious participants (33 women) received the ARB losartan (50 mg) or placebo. At drug peak level, participants encoded images of animals and landscapes before undergoing functional magnetic resonance imaging, where they viewed the encoded familiar images and unseen novel images to be memorized and classified as animals/landscapes. Memory recognition was assessed 1 hour after functional magnetic resonance imaging. To analyze neural effects, whole-brain analysis, hippocampus region-of-interest analysis, and exploratory multivariate pattern similarity analysis were employed.

Results

ARBs facilitated parahippocampal processing. In the whole-brain analysis, losartan enhanced brain activity for familiar images in the parahippocampal gyrus (PHC), anterior cingulate cortex, and caudate. For novel images, losartan enhanced brain activity in the PHC only. Pattern similarity analysis showed that losartan increased neural stability in the PHC when processing novel and familiar images. However, there were no drug effects on memory recognition or hippocampal activation.

Conclusions

Given that the hippocampus receives major input from the PHC, our findings suggest that ARBs may modulate higher-order visual processing through parahippocampal involvement, potentially preserving intact memory input. Future research needs to directly investigate whether this effect may underlie the preventive effects of ARBs in the development of posttraumatic stress disorder.

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.

The central renin-angiotensin system: A genetic pathway, functional decoding, and selective target engagement characterization in humans

Accumulating evidence suggests that the brain renin angiotensin system (RAS) plays a pivotal role in the regulation of cognition and behavior as well as in the neuropathology of neurological and mental disorders. The angiotensin II type 1 receptor (AT1R) mediates most functional and neuropathology-relevant actions associated with the central RAS. However, an overarching comprehension to guide translation and utilize the therapeutic potential of the central RAS in humans is currently lacking. We conducted a comprehensive characterization of the RAS using an innovative combination of transcriptomic gene expression mapping, image-based behavioral decoding, and pre-registered randomized controlled discovery-replication pharmacological resting-state functional magnetic resonance imaging (fMRI) trials (N = 132) with a selective AT1R antagonist. The AT1R exhibited a particular dense expression in a subcortical network encompassing the thalamus, striatum, and amygdalo-hippocampal formation. Behavioral decoding of the AT1R gene expression brain map showed an association with memory, stress, reward, and motivational processes. Transient pharmacological blockade of the AT1R further decreased neural activity in subcortical systems characterized by a high AT1R expression, while increasing functional connectivity in the cortico-basal ganglia-thalamo-cortical circuitry. Effects of AT1R blockade on the network level were specifically associated with the transcriptomic signatures of the dopaminergic, opioid, acetylcholine, and corticotropin-releasing hormone signaling systems. The robustness of the results was supported in an independent pharmacological fMRI trial. These findings present a biologically informed comprehensive characterization of the central AT1R pathways and their functional relevance on the neural and behavioral level in humans.

Sex-dependent effects of angiotensin type 2 receptor expressing medial prefrontal cortex (mPFC) interneurons in fear extinction learning

Background

The renin-angiotensin system (RAS) has been identified as a potential therapeutic target for PTSD, though its mechanisms are not well understood. Brain angiotensin type 2 receptors (AT2Rs) are a subtype of angiotensin II receptors located in stress and anxiety-related regions, including the medial prefrontal cortex (mPFC), but their function and mechanism in the mPFC remain unexplored. We therefore used a combination of imaging, cre/lox, and behavioral methods to investigate mPFC-AT2R-expressing neuron involvement in fear learning.

Methods

To characterize mPFC-AT2R-expressing neurons in the mPFC, AT2R-Cre/td-Tomato male and female mice were used for immunohistochemistry (IHC). mPFC brain sections were stained with glutamatergic or interneuron markers, and density of AT2R+ cells and colocalization with each marker was quantified. To assess fear-related behaviors in AT2R-flox mice, we selectively deleted AT2R from mPFC neurons using an AAV-Cre virus. Mice then underwent Pavlovian auditory fear conditioning, approach/avoidance, and locomotion testing.

Results

IHC results revealed that AT2R is densely expressed in the mPFC. Furthermore, AT2R is primarily expressed in somatostatin interneurons in females but not males. Following fear conditioning, mPFC-AT2R deletion impaired extinction in female but not male mice. Locomotion was unaltered by mPFC-AT2R deletion in males or females, while AT2R-deleted females had increased exploratory behavior.

Conclusion

These results lend support for mPFC-AT2R+ neurons as a novel subgroup of somatostatin interneurons that influence fear extinction in a sex-dependent manner. This furthers underscores the role of mPFC in top-down regulation and a unique role for peptidergic (ie., angiotensin) mPFC regulation of fear and sex differences.

Sex-dependent effects of angiotensin II type 1 receptor blocker on molecular and behavioral changes induced by single prolonged stress

Post-traumatic stress disorder (PTSD) is a neuropsychiatric disorder that not only entails alterations in fear behavior and anxiety but also includes neuroendocrine dysfunctions involving the hypothalamic pituitary adrenal (HPA) axis and the renin-angiotensin system. Recent preclinical studies demonstrate that activation of the angiotensin type 1 receptor (AT1R) in the paraventricular region of the hypothalamus (PVR) promotes anxiety-like behaviors and enables microglia proliferation. An increase in microglia and anxiety-like behavior also occurs in the PTSD animal model single-prolonged stress (SPS). In the present study, we tested whether AT1Rs contribute to the effects of SPS on behavior and microglia in brain structures important for HPA axis regulation and fear behavior. To test this, male and female animals were exposed to SPS and then given the oral AT1R antagonist candesartan beginning one week later. Candesartan did not alter auditory fear conditioning or extinction in SPS-exposed male or female animals. However, we found that the male animals exposed to SPS showed increased anxiety-like behavior, which was reversed by candesartan. In contrast, neither SPS nor candesartan altered anxiety-like behavior in the female animals. At the molecular level, SPS increased the cellular expression of AT1Rs in the PVR of male animals and candesartan reversed this effect, whereas AT1Rs in the PVR of females were unaltered by either SPS or candesartan. Iba1-expressing microglia increased in the PVR after SPS exposure and was reversed by candesartan in both sexes suggesting that SPS stimulates AT1Rs to increase microglia in the PVR. Collectively, these results suggest that the contribution of AT1Rs to the molecular and behavioral effects of SPS is sex-dependent.

Antihypertensive Medications and PTSD Incidence in a Trauma Cohort

Objective: Antihypertensive medications have been examined as agents for posttraumatic stress disorder (PTSD) prevention in trauma-exposed individuals, given well-documented associations between PTSD and increased risk of cardiovascular disease and purported trauma-relevant mechanisms of action for these medications. Evidence regarding the effectiveness of such drugs for this purpose remains mixed.

Methods: We conducted a national population-based cohort study using data from Danish national registries to assess whether 4 classes of antihypertensive drugs (beta-adrenoceptor blockers [beta blockers], angiotensin II receptor blockers [ARBs], angiotensin-converting enzyme [ACE] inhibitors, and calcium channel blockers) were associated with a decreased incidence of PTSD (diagnosed according to ICD-10) over a 22-year study period. Data for this study originated from a population-based cohort of over 1.4 million persons who experienced a traumatic event between 1994 and 2016 in Denmark. We calculated the incidence rate of PTSD per 100,000 person-years among persons who filled a prescription for each class of drug in the 60 days prior to a traumatic event and for corresponding unexposed comparison groups. We then used Cox proportional hazards regression to compare the rate of PTSD among persons who filled an antihypertensive medication prescription within 60 days before their trauma to the rate among persons who did not.

Results: We found evidence that calcium channel blockers were associated with a decreased incidence of PTSD (adjusted hazard ratio = 0.63, 95% confidence interval [CI] = 0.34, 1.2); all other antihypertensive medication classes had null or near null associations.

Conclusions: These findings lay a foundation for additional research focusing on antihypertensive medications that appear most effective in reducing PTSD incidence following trauma and for additional replication work aimed at continuing to clarify the disparate findings reported in the literature to date.

The Intersectionality of Sex and Race in the Relationship Between Posttraumatic Stress Disorder and Cardiovascular Disease: A Scoping Review

Objectives: Posttraumatic stress disorder (PTSD) has been linked with cardiovascular disease (CVD), suggesting a risk for negative health outcomes among individuals with PTSD. This review synthesizes the temporal relationship between PTSD and CVD and highlights the intersection of sex and race. Methods: Covidence was used to systematically review the literature published between 1980 and 2020. Results: 176 studies were extracted. 68 (38.64%) of the studies were a predominantly male sample. 31 studies (17.61%) were a predominantly female sample. Most reported participants of both sexes (n = 72; 40.91%) and only 5 (2.84%) did not report respondent sex. No studies reported transgender participants. 110 (62.5%) studies reported racial and ethnic diversity in their study population, 18 (10.22%) described a completely or predominantly white sample, and 48 (27.27%) did not report race or ethnicity of their study population. Conclusion: A compelling number of studies did not identify sex differences in the link between PTSD and CVD or failed to report race and ethnicity. Investigating sex, race, ethnicity, and the temporal relationship between PTSD and CVD are promising avenues for future research.

Angiotensin II Regulates the Neural Expression of Subjective Fear in Humans: A Precision Pharmaco-Neuroimaging Approach

BACKGROUND

Rodent models and pharmacological neuroimaging studies in humans have been used to test novel pharmacological agents to reduce fear. However, these strategies are limited with respect to determining process-specific effects on the actual subjective experience of fear, which represents the key symptom that motivates patients to seek treatment. In this study, we used a novel precision pharmacological functional magnetic resonance imaging approach based on process-specific neuroaffective signatures to determine effects of the selective angiotensin II type 1 receptor (AT1R) antagonist losartan on the subjective experience of fear.

METHODS

In a double-blind, placebo-controlled, randomized pharmacological functional magnetic resonance imaging design, healthy participants (N = 87) were administered 50 mg losartan or placebo before they underwent an oddball paradigm that included neutral, novel, and fear oddballs. Effects of losartan on brain activity and connectivity as well as on process-specific multivariate neural signatures were examined.

RESULTS

AT1R blockade selectively reduced neurofunctional reactivity to fear-inducing visual oddballs in terms of attenuating dorsolateral prefrontal activity and amygdala-ventral anterior cingulate communication. Neurofunctional decoding further demonstrated fear-specific effects in that AT1R blockade reduced the neural expression of subjective fear but not of threat or nonspecific negative affect and did not influence reactivity to novel oddballs.

CONCLUSIONS

These results show a specific role of the AT1R in regulating the subjective fear experience and demonstrate the feasibility of a precision pharmacological functional magnetic resonance imaging approach to the affective characterization of novel receptor targets for fear in humans.

Supplementary Pharmacotherapy for the Behavioral Abnormalities Caused by Stressors in Humans, Focused on Post-Traumatic Stress Disorder (PTSD)

Used as a supplement to psychotherapy, pharmacotherapy that addresses all of the known metabolic and genetic contributions to the pathogenesis of psychiatric conditions caused by stressors would require an inordinate number of drugs. Far simpler is to address the abnormalities caused by those metabolic and genetic changes in the cell types of the brain that mediate the behavioral abnormality. Relevant data regarding the changed brain cell types are described in this article and are derived from subjects with the paradigmatic behavioral abnormality of PTSD and from subjects with traumatic brain injury or chronic traumatic encephalopathy. If this analysis is correct, then therapy is required that benefits all of the affected brain cell types; those are astrocytes, oligodendrocytes, synapses and neurons, endothelial cells, and microglia (the pro-inflammatory (M1) subtype requires switching to the anti-inflammatory (M2) subtype). Combinations are advocated using several drugs, erythropoietin, fluoxetine, lithium, and pioglitazone, that benefit all of the five cell types, and that should be used to form a two-drug combination, suggested as pioglitazone with either fluoxetine or lithium. Clemastine, fingolimod, and memantine benefit four of the cell types, and one chosen from those could be added to the two-drug combination to form a three-drug combination. Using low doses of chosen drugs will limit both toxicity and drug-drug interactions. A clinical trial is required to validate both the advocated concept and the choice of drugs.

Correlates of Skin Conductance Reactivity to Stroke-Related Trauma Reminders During Hospitalization for Stroke

Objective

Although several risk factors for stroke-induced posttraumatic stress disorder (PTSD) have been identified, objective risk measures that can be detected in the acute aftermath of these events are needed. This study is the first to collect an objective measure of psychophysiological arousal-skin conductance (SC) reactivity to a trauma interview-in patients after stroke or transient ischemic attack (TIA) and investigate correlates of SC reactivity.

Methods

Mobile SC measurement during a resting baseline and standardized trauma interview was performed in-hospital in 98 individuals following stroke/TIA. We examined associations between several stroke-induced PTSD risk factors (sociodemographic, psychosocial, and medical characteristics) and SC reactivity to a trauma interview involving a free-response recalling of the stroke/TIA event.

Results

Of the sociodemographic, psychosocial, medical characteristics examined as correlates to SC reactivity to recalling the stroke/TIA event, 2 factors reflecting aspects of prior and in-hospital experience were significantly associated with this indicator of sympathetic nervous system activation. A greater cumulative trauma burden was significantly associated with greater SC reactivity (r = .23, P = .04). Additionally, individuals administered benzodiazepines in-hospital had significantly greater SC reactivity to recalling the stroke/TIA event (M = 1.51, SD = 1.52) than those who were not (M = 0.76, SD = 1.16; P = .01). Greater cumulative trauma burden remained significantly associated with greater SC reactivity when adjusting for age and in-hospital benzodiazepine administration (β=0.22, P = .04).

Conclusion

This study demonstrated that SC reactivity was related to both behavioral and psychological risk factors for PTSD after a stroke/TIA event. Additionally, we demonstrated the feasibility of a low-cost, mobile measurement of SC that can be conducted in-hospital in a novel patient population: individuals with a medical trauma. With this measure, we were able to identify those individuals with the greatest trauma-related sympathetic nervous system reactivity in the days following a medical trauma. Future research is needed to determine whether SC reactivity may be leveraged in the development of brief, noninvasive screening measures for enhancing PTSD risk prediction.

Psychological and biological mechanisms linking trauma with cardiovascular disease risk

Cardiovascular disease (CVD) is the leading cause of death and disability worldwide, and experiences of psychological trauma have been associated with subsequent CVD onset. Identifying key pathways connecting trauma with CVD has the potential to inform more targeted screening and intervention efforts to offset elevated cardiovascular risk. In this narrative review, we summarize the evidence for key psychological and biological mechanisms linking experiences of trauma with CVD risk. Additionally, we describe various methodologies for measuring these mechanisms in an effort to inform future research related to potential pathways. With regard to mechanisms involving posttraumatic psychopathology, the vast majority of research on psychological distress after trauma and CVD has focused on posttraumatic stress disorder (PTSD), even though posttraumatic psychopathology can manifest in other ways as well. Substantial evidence suggests that PTSD predicts the onset of a range of cardiovascular outcomes in trauma-exposed men and women, yet more research is needed to better understand posttraumatic psychopathology more comprehensively and how it may relate to CVD. Further, dysregulation of numerous biological systems may occur after trauma and in the presence of posttraumatic psychopathology; these processes of immune system dysregulation and elevated inflammation, oxidative stress, mitochondrial dysfunction, renin-angiotensin system dysregulation, and accelerated biological aging may all contribute to subsequent cardiovascular risk, although more research on these pathways in the context of traumatic stress is needed. Given that many of these mechanisms are closely intertwined, future research using a systems biology approach may prove fruitful for elucidating how processes unfold to contribute to CVD after trauma.

The Angiotensin Antagonist Losartan Modulates Social Reward Motivation and Punishment Sensitivity via Modulating Midbrain-Striato-Frontal Circuits

Social deficits and dysregulations in dopaminergic midbrain-striato-frontal circuits represent transdiagnostic symptoms across psychiatric disorders. Animal models suggest that interactions between the dopamine (DA) and renin-angiotensin system (RAS) may modulate learning and reward-related processes. The present study therefore examined the behavioral and neural effects of the Angiotensin II type 1 receptor (AT1R) antagonist losartan on social reward and punishment processing in humans. A preregistered randomized double-blind placebo-controlled between-subject pharmacological design was combined with a social incentive delay (SID) functional MRI (fMRI) paradigm during which subjects could avoid social punishment or gain social reward. Healthy volunteers received a single-dose of losartan (50 mg, n = 43, female = 17) or placebo (n = 44, female = 20). We evaluated reaction times (RTs) and emotional ratings as behavioral and activation and functional connectivity as neural outcomes. Relative to placebo, losartan modulated the reaction time and arousal differences between social punishment and social reward. On the neural level the losartan-enhanced motivational salience of social rewards was accompanied by stronger ventral striatum-prefrontal connectivity during reward anticipation. Losartan increased the reward-neutral difference in the ventral tegmental area (VTA) and attenuated VTA associated connectivity with the bilateral insula in response to punishment during the outcome phase. Thus, losartan modulated approach-avoidance motivation and emotional salience during social punishment versus social reward via modulating distinct core nodes of the midbrain-striato-frontal circuits. The findings document a modulatory role of the renin-angiotensin system in these circuits and associated social processes, suggesting a promising treatment target to alleviate social dysregulations.SIGNIFICANCE STATEMENT Social deficits and anhedonia characterize several mental disorders and have been linked to the midbrain-striato-frontal circuits of the brain. Based on initial findings from animal models we here combine the pharmacological blockade of the Angiotensin II type 1 receptor (AT1R) via losartan with functional MRI (fMRI) to demonstrate that AT1R blockade enhances the motivational salience of social rewards and attenuates the negative impact of social punishment via modulating the communication in the midbrain-striato-frontal circuits in humans. The findings demonstrate for the first time an important role of the AT1R in social reward processing in humans and render the AT1R as promising novel treatment target for social and motivational deficits in mental disorders.

Enhancing Fear Extinction: Pharmacological Approaches

Extinction is the process by which the memory of a learned conditioned association decreases over time and with introduction of new associations. It is a vital part of fear learning, and it is critical to recovery in multiple fear-related disorders, including Specific and Social Phobias, Panic Disorder, Obsessive Compulsive Disorder (OCD), and Posttraumatic Stress Disorder (PTSD). The process of extinction is also the underlying mechanism for recovery in gold-standard therapies for PTSD, including prolonged exposure, cognitive processing therapy, eye movement desensitization and procession, as well as other empirically-based paradigms. Pharmacological modulators of extinction are thus promising targets for treatment of fear-related disorders. We focus here on emerging psychopharmacological treatments to facilitate extinction: D-cycloserine, scopolamine, losartan, ketamine, and 3,4-methylenedioxymethamphetamine. We also provide an overview of recent advances in molecular pathways that show promise as targets for extincion and inhibitory learning, including pathways related to cannabinoid, brain-derived neurotrophic factor, hypothalamic-pituitary-adrenal signaling, and promising work in neurosteroid compounds.

Involvement of the brain-heart axis in the link between PTSD and cardiovascular disease

Posttraumatic stress disorder (PTSD) has long been associated with a heightened risk of cardiovascular disease (CVD). A number of mechanisms have been implicated to underlie this brain-heart axis relationship, such as altered functioning of the autonomic nervous system and increased systemic inflammation. While neural alterations have repeatedly been observed in PTSD, they are rarely considered in the PTSD-CVD link. The brain-heart axis is a pathway connecting frontal and limbic brain regions to the brainstem and periphery via the autonomic nervous system and it may be a promising model for understanding CVD risk in PTSD given its overlap with PTSD neural deficits. We first provide a summary of the primary mechanisms implicated in the association between PTSD and CVD. We then review the brain-heart axis and its relevance to PTSD, as well as findings from PTSD trials demonstrating that a number of PTSD treatments have effects on areas of the brain-heart axis. Finally, we discuss sex considerations in the PTSD-CVD link. A critical next step in this study is to determine if PTSD treatments that affect the brain-heart axis (e.g., brain stimulation that improves autonomic function) also reduce the risk of CVD.

The neurobiology of childhood trauma-aldosterone and blood pressure changes in a community sample

OBJECTIVE

Childhood trauma is an important risk factor for the onset and course of psychiatric disorders and particularly major depression. Recently, the renin-angiotensin-aldosterone system, one of the core stress hormone systems, has been demonstrated to be modified by childhood trauma.

METHODS

Childhood trauma was obtained using the Childhood Trauma Questionnaire (CTQ) in a community-dwelling sample (N = 2038). Plasma concentrations of renin and aldosterone were measured in subjects with childhood trauma (CT; N = 385) vs. subjects without this experience (NoCT; N = 1653). Multivariable linear regression models were calculated to assess the associations between CTQ, systolic and diastolic blood pressure, renin and aldosterone concentrations, and the ratio of aldosterone and systolic blood pressure (A/SBP).

RESULTS

CT subjects demonstrated higher plasma aldosterone (A) concentrations, a lower systolic and diastolic blood pressure, and a higher A/SBP. In addition, both aldosterone concentrations, as well as A/SBP, correlated with the severity of childhood trauma. These findings could not be attributed to differences in concomitant medication.

CONCLUSIONS

In conclusion, childhood trauma was associated with neurobiological markers, which may impact the risk for psychiatric disorders, primarily major depression. The altered A/SBP ratio points to a desensitisation of peripheral mineralocorticoid receptor function, which may be a target for therapeutic interventions.

Childhood Violence Exposure Predicts High Blood Pressure in Black American Young Adults

OBJECTIVE

To test the impact of childhood adversity, including community violence exposure, on hypertension risk in Black American young adults to understand what risk factors (eg, prenatal factors, later exposures) and ages of adversity exposure increased hypertension risk.

STUDY DESIGN

The study included 396 Black American participants with data from prenatal, birth, and age 7-, 14-, and 19-year visits. At age 19 years, individuals with blood pressure (BP) measures >120 mmHg systolic and/or >80 mmHg diastolic were classified as having high blood pressure (HBP), and those with BP <120/80 mmHg were classified as normal. Associations between prenatal and birth risk factors; childhood adversity at age 7, 14, and 19 years; age 19 body mass index (BMI); and both systolic and diastolic BP at age 19 were tested using logistic regression models.

RESULTS

Age 19 BMI was positively associated with systolic and diastolic HBP status at age 19. Controlling for all covariates, community violence exposure at age 7 and 19 years was associated with 2.2-fold (95% CI, 1.242-3.859) and 2.0-fold (95% CI, 1.052-3.664) greater odds of systolic HBP, respectively, at age 19 years. Prenatal risk, birth risk, and other dimensions of childhood adversity were not associated with HBP in this cohort.

CONCLUSION

Childhood community violence exposure is a significant risk factor for HBP in young adults. As Black American children typically experience more community violence exposure than other American children, our results suggest that racial disparities in childhood community violence exposure may contribute to racial disparities in adult hypertension burden.

Pharmacological strategies for post-traumatic stress disorder (PTSD): From animal to clinical studies

Post-traumatic stress disorder (PTSD) is a disabling psychiatric condition with a critical familiar, personal, and social impact. Patients diagnosed with PTSD show various symptoms, including anxiety, depression, psychotic episodes, and sleep disturbances, complicating their therapeutic management. Only sertraline and paroxetine, two selective serotonin reuptake inhibitors, are approved by different international agencies to treat PTSD. In addition, these drugs are generally combined with psychotherapy to achieve positive results. However, these pharmacological strategies present limited efficacy. Nearly half of the PTSD patients do not experience remission of symptoms, possibly due to the high prevalence of psychiatric comorbidities. Therefore, in clinical practice, other off-label medications are common, even though the effectiveness of these drugs needs to be further investigated. In this line, antipsychotics, antiepileptics, adrenergic blockers, benzodiazepines, and other emerging pharmacological agents have aroused interest as potential therapeutic tools to improve some specific symptoms of PTSD. Thus, this review is focused on the most widely used drugs for the pharmacological treatment of PTSD with a translational approach, including clinical and preclinical studies, to emphasize the need to develop safer and more effective medications.

Hypothalamic-pituitary-adrenal axis and renin-angiotensin-aldosterone system in adulthood PTSD and childhood maltreatment history

Accumulated evidence shows that psychological trauma and posttraumatic stress disorder (PTSD) are associated with dysfunction in the hypothalamic-pituitary-adrenal (HPA) axis. Besides the HPA axis hormones, recent evidence suggests that the renin-angiotensin-aldosterone (RAA) system and genetic factors may be involved in trauma/PTSD as well as in HPA axis regulation. This study attempted to better understand the HPA axis function in relation to PTSD and childhood maltreatment by simultaneously examining RAA system and genetic polymorphisms of candidate genes. Here we studied 69 civilian women with PTSD and 107 healthy control women without DSM-IV-based traumatic experience. Childhood maltreatment history was assessed with the Childhood Trauma Questionnaire. PTSD severity was assessed with the Posttraumatic Diagnostic Scale. Functional disability was assessed with the Sheehan Disability Scale. HPA axis was examined by measuring blood levels of cortisol, adrenocorticotropic hormone, and dehydroepiandrosterone-sulphate (DHEA-S). RAA system was examined by measuring blood renin and aldosterone levels. The FKBP5 rs1360780 and CACNA1C rs1006737 polymorphisms were genotyped. No significant differences were seen between patients and controls in any of the five hormone levels. DHEA-S levels were significantly negatively correlated with overall PTSD severity (p = 0.003) and functional disability (p = 0.008). A two-way analysis of variance with diagnostic groups and genotypes as fixed factors revealed that patients with the rs1006737 A-allele had significantly lower DHEA-S levels than patients with the GG genotype (p = 0.002) and controls with the A-allele (p = 0.006). Childhood maltreatment history was not significantly correlated with any of the five hormone levels. These results were generally unchanged after controlling for the potentially confounding effect of age, depression, and anxiety. Our findings suggest that lower DHEA-S levels could indicate more severe subtype of PTSD, the association of which might be partly modified by the CACNA1C polymorphism.

A prospective examination of sex differences in posttraumatic autonomic functioning

BACKGROUND

Cross-sectional studies have found that individuals with posttraumatic stress disorder (PTSD) exhibit deficits in autonomic functioning. While PTSD rates are twice as high in women compared to men, sex differences in autonomic functioning are relatively unknown among trauma-exposed populations. The current study used a prospective design to examine sex differences in posttraumatic autonomic functioning.

METHODS

192 participants were recruited from emergency departments following trauma exposure (Mean age = 35.88, 68.2% female). Skin conductance was measured in the emergency department; fear conditioning was completed two weeks later and included measures of blood pressure (BP), heart rate (HR), and high frequency heart rate variability (HF-HRV). PTSD symptoms were assessed 8 weeks after trauma.

RESULTS

2-week systolic BP was significantly higher in men, while 2-week HR was significantly higher in women, and a sex by PTSD interaction suggested that women who developed PTSD demonstrated the highest HR levels. Two-week HF-HRV was significantly lower in women, and a sex by PTSD interaction suggested that women with PTSD demonstrated the lowest HF-HRV levels. Skin conductance response in the emergency department was associated with 2-week HR and HF-HRV only among women who developed PTSD.

CONCLUSIONS

Our results indicate that there are notable sex differences in autonomic functioning among trauma-exposed individuals. Differences in sympathetic biomarkers (BP and HR) may have implications for cardiovascular disease risk given that sympathetic arousal is a mechanism implicated in this risk among PTSD populations. Future research examining differential pathways between PTSD and cardiovascular risk among men versus women is warranted.

PTSD as an Endothelial Disease: Insights From COVID-19

SARS-CoV-2 virus, the etiologic agent of COVID-19, has affected almost every aspect of human life, precipitating stress-related pathology in vulnerable individuals. As the prevalence rate of posttraumatic stress disorder in pandemic survivors exceeds that of the general and special populations, the virus may predispose to this disorder by directly interfering with the stress-processing pathways. The SARS-CoV-2 interactome has identified several antigens that may disrupt the blood-brain-barrier by inducing premature senescence in many cell types, including the cerebral endothelial cells. This enables the stress molecules, including angiotensin II, endothelin-1 and plasminogen activator inhibitor 1, to aberrantly activate the amygdala, hippocampus, and medial prefrontal cortex, increasing the vulnerability to stress related disorders. This is supported by observing the beneficial effects of angiotensin receptor blockers and angiotensin converting enzyme inhibitors in both posttraumatic stress disorder and SARS-CoV-2 critical illness. In this narrative review, we take a closer look at the virus-host dialog and its impact on the renin-angiotensin system, mitochondrial fitness, and brain-derived neurotrophic factor. We discuss the role of furin cleaving site, the fibrinolytic system, and Sigma-1 receptor in the pathogenesis of psychological trauma. In other words, learning from the virus, clarify the molecular underpinnings of stress related disorders, and design better therapies for these conditions. In this context, we emphasize new potential treatments, including furin and bromodomains inhibitors.

Randomized, Placebo-Controlled Trial of the Angiotensin Receptor Antagonist Losartan for Posttraumatic Stress Disorder

BACKGROUND

Evidence-based pharmacological treatments for posttraumatic stress disorder (PTSD) are few and of limited efficacy. Previous work suggests that angiotensin type 1 receptor inhibition facilitates fear inhibition and extinction, important for recovery from PTSD. This study tests the efficacy of the angiotensin type 1 receptor antagonist losartan, an antihypertensive drug, repurposed for the treatment of PTSD.

METHODS

A randomized controlled trial was conducted for 10 weeks in 149 men and women meeting DSM-5 PTSD criteria. Losartan (vs. placebo) was flexibly titrated from 25 to 100 mg/day by week 6 and held at highest tolerated dose until week 10. Primary outcome was the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) change score at 10 weeks from baseline. A key secondary outcome was change in CAPS-5 associated with a single nucleotide polymorphism of the ACE gene. Additional secondary outcomes included changes in the PTSD Checklist for DSM-5 and the Patient Health Questionnaire-9, and proportion of responders with a Clinical Global Impressions-Improvement scale of "much improved" or "very much improved."

RESULTS

Both groups had robust improvement in PTSD symptoms, but there was no significant difference on the primary end point, CAPS-5 measured as week 10 change from baseline, between losartan and placebo (mean change difference, 0.9, 95% confidence interval, -3.2 to 5.0). There was no significant difference in the proportion of Clinical Global Impressions-Improvement scale responders for losartan (58.6%) versus placebo (57.9%), no significant differences in changes in PTSD Checklist for DSM-5 or Patient Health Questionnaire-9, and no association between ACE genotype and CAPS-5 improvement on losartan.

CONCLUSIONS

At these doses and durations, there was no significant benefit of losartan compared with placebo for the treatment of PTSD. We discuss implications for failure to determine the benefit of a repurposed drug with strong a priori expectations of success based on preclinical and epidemiological data.

Examining Individual and Synergistic Contributions of PTSD and Genetics to Blood Pressure: A Trans-Ethnic Meta-Analysis

Growing research suggests that posttraumatic stress disorder (PTSD) may be a risk factor for poor cardiovascular health, and yet our understanding of who might be at greatest risk of adverse cardiovascular outcomes after trauma is limited. In this study, we conducted the first examination of the individual and synergistic contributions of PTSD symptoms and blood pressure genetics to continuous blood pressure levels. We harnessed the power of the Psychiatric Genomics Consortium-PTSD Physical Health Working Group and investigated these associations across 11 studies of 72,224 trauma-exposed individuals of European (n = 70,870) and African (n = 1,354) ancestry. Genetic contributions to blood pressure were modeled via polygenic scores (PGS) for systolic blood pressure (SBP) and diastolic blood pressure (DBP) that were derived from a prior trans-ethnic blood pressure genome-wide association study (GWAS). Results of trans-ethnic meta-analyses revealed significant main effects of the PGS on blood pressure levels [SBP: β = 2.83, standard error (SE) = 0.06, p < 1E-20; DBP: β = 1.32, SE = 0.04, p < 1E-20]. Significant main effects of PTSD symptoms were also detected for SBP and DBP in trans-ethnic meta-analyses, though there was significant heterogeneity in these results. When including data from the largest contributing study - United Kingdom Biobank - PTSD symptoms were negatively associated with SBP levels (β = -1.46, SE = 0.44, p = 9.8E-4) and positively associated with DBP levels (β = 0.70, SE = 0.26, p = 8.1E-3). However, when excluding the United Kingdom Biobank cohort in trans-ethnic meta-analyses, there was a nominally significant positive association between PTSD symptoms and SBP levels (β = 2.81, SE = 1.13, p = 0.01); no significant association was observed for DBP (β = 0.43, SE = 0.78, p = 0.58). Blood pressure PGS did not significantly moderate the associations between PTSD symptoms and blood pressure levels in meta-analyses. Additional research is needed to better understand the extent to which PTSD is associated with high blood pressure and how genetic as well as contextual factors may play a role in influencing cardiovascular risk.

Onset and recurrence of psychiatric disorders associated with anti-hypertensive drug classes

The major anti-hypertensive (AHT) drug classes have been associated with differential risks of psychiatric disorders. However, existing data are limited largely to depression, and confounding variables have not always been controlled for. We sought to fill the evidence gap, using TriNetX Analytics, an electronic health records network. Amongst 58.6 million patients aged 18-90 years, patients prescribed a calcium channel blocker (CCB) were compared with those taking a diuretic, angiotensin-converting enzyme inhibitor (ACEI), angiotensin receptor blocker (ARB), or β-blocker. Cohorts were propensity score-matched for age, sex, race, and blood pressure. Over a 2-year exposure period, we measured the incidence and risk ratio of a first diagnosis (ICD-10 codes), or a recurrence, of psychotic, affective, and anxiety disorders, as well as substance use disorders and sleep disorders. Cohort sizes ranged from 33,734 to 322,814. CCBs were associated with a lower incidence of psychotic, affective, and anxiety disorders than β-blockers (risk ratios 0.69-0.99) and a higher incidence than ARBs (risk ratios 1.04-2.23) for both first and recurrent diagnoses. Comparisons of CCBs with ACEIs or diuretics showed smaller risk ratios that varied between disorders, and between first episode and recurrence. AHT classes were also associated with the incidence of substance use and sleep disorders. Results remained largely unchanged after more extensive cohort matching for additional potential confounders. In a secondary analysis, a comparison between ARBs and ACEIs showed lower rates of psychotic, affective, and substance use disorders with ARBs, but higher risks of anxiety and sleep disorders. In conclusion, AHT classes are differentially associated with the incidence of psychiatric disorders. ARBs show the most advantageous profile and β-blockers the least. The apparent beneficial effects of ARBs merit further study.