Is PTSD-Phenotype Associated with HPA-Axis Sensitivity? Feedback Inhibition and Other Modulating Factors of Glucocorticoid Signaling Dynamics

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.

D-Pinitol mitigates post-traumatic stress disorder-like behaviors induced by single prolonged stress in mice through mineralocorticoid receptor antagonism

Post-traumatic stress disorder (PTSD) is a mental illness that can occur in individuals who have experienced trauma. Current treatments for PTSD, typically serotonin reuptake inhibitors, have limited effectiveness for patients and often cause serious adverse effects. Therefore, a novel class of treatment with better pharmacological profile is necessary. D-Pinitol has been reported to be effective for depression and anxiety disorders, but there are no reports associated with PTSD. In the present study, we investigated the effects of D-pinitol in a mouse model of PTSD induced by a single prolonged stress (SPS) protocol. We examined the therapeutic effects of D-pinitol on emotional and cognitive impairments in the SPS mouse model. We also investigated the effects of D-pinitol on fear memory formation. Mineralocorticoid receptor transactivation assay, Western blot, and quantitative PCR were employed to investigate how D-pinitol exerts its pharmacological activities. D-Pinitol ameliorated PTSD-like behaviors in a SPS mouse model. D-Pinitol also normalized the increased mRNA expression levels and protein levels of the mineralocorticoid receptor in the amygdala. A mineralocorticoid receptor agonist reversed the effects of D-pinitol on fear extinction and recall, and the antagonistic property of D-pinitol against the mineralocorticoid receptor was confirmed in vitro. Our findings suggest that D-pinitol could serve as a potential therapeutic agent for PTSD due to its antagonistic effect on the mineralocorticoid receptor.

Assessing and Modelling of Post-Traumatic Stress Disorder Using Molecular and Functional Biomarkers

Post-traumatic stress disorder (PTSD) is a complex psychological disorder that develops following exposure to traumatic events. PTSD is influenced by catalytic factors such as dysregulated hypothalamic-pituitary-adrenal (HPA) axis, neurotransmitter imbalances, and oxidative stress. Genetic variations may act as important catalysts, impacting neurochemical signaling, synaptic plasticity, and stress response systems. Understanding the intricate gene networks and their interactions is vital for comprehending the underlying mechanisms of PTSD. Focusing on the catalytic factors of PTSD is essential because they provide valuable insights into the underlying mechanisms of the disorder. By understanding these factors and their interplay, researchers may uncover potential targets for interventions and therapies, leading to more effective and personalized treatments for individuals with PTSD. The aforementioned gene networks, composed of specific genes associated with the disorder, provide a comprehensive view of the molecular pathways and regulatory mechanisms involved in PTSD. Through this study valuable insights into the disorder's underlying mechanisms and opening avenues for effective treatments, personalized interventions, and the development of biomarkers for early detection and monitoring are provided.

On making (and turning adaptive to) maladaptive aversive memories in laboratory rodents

Fear conditioning and avoidance tasks usually elicit adaptive aversive memories. Traumatic memories are more intense, generalized, inflexible, and resistant to attenuation via extinction- and reconsolidation-based strategies. Inducing and assessing these dysfunctional, maladaptive features in the laboratory are crucial to interrogating posttraumatic stress disorder's neurobiology and exploring innovative treatments. Here we analyze over 350 studies addressing this question in adult rats and mice. There is a growing interest in modeling several qualitative and quantitative memory changes by exposing already stressed animals to freezing- and avoidance-related tests or using a relatively high aversive training magnitude. Other options combine aversive/fearful tasks with post-acquisition or post-retrieval administration of one or more drugs provoking neurochemical or epigenetic alterations reported in the trauma aftermath. It is potentially instructive to integrate these procedures and incorporate the measurement of autonomic and endocrine parameters. Factors to consider when defining the organismic and procedural variables, partially neglected aspects (sex-dependent differences and recent vs. remote data comparison) and suggestions for future research (identifying reliable individual risk and treatment-response predictors) are discussed.

Pathophysiological aspects of complex PTSD - a neurobiological account in comparison to classic posttraumatic stress disorder and borderline personality disorder

Despite a great diagnostic overlap, complex posttraumatic stress disorder (CPTSD) has been recognised by the ICD-11 as a new, discrete entity and recent empirical evidence points towards a distinction from simple posttraumatic stress disorder (PTSD) and borderline personality disorder (BPD). The development and maintenance of these disorders is sustained by neurobiological alterations and studies using functional magnetic resonance imaging (fMRI) may further contribute to a clear differentiation of CPTSD, PTSD and BPD. However, there are no existing fMRI studies directly comparing CPTSD, PTSD and BPD. In addition to a summarization of diagnostic differences and similarities, the current review aims to provide a qualitative comparison of neuroimaging findings on affective, attentional and memory processing in CPTSD, PTSD and BPD. Our narrative review alludes to an imbalance in limbic-frontal brain networks, which may be partially trans-diagnostically linked to the degree of trauma symptoms and their expression. Thus, CPTSD, PTSD and BPD may underlie a continuum where similar brain regions are involved but the direction of activation may constitute its distinct symptom expression. The neuronal alterations across these disorders may conceivably be better understood along a symptom-based continuum underlying CPTSD, PTSD and BPD. Further research is needed to amend for the heterogeneity in experimental paradigms and sample criteria.

An orchestrating role of mitochondria in the origin and development of post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) is one of the most discussed and actively researched areas in medicine, psychiatry, neurophysiology, biochemistry and rehabilitation over the last decades. Multiple causes can trigger post-traumatic stress disorder. Humans subjected to violence, participants in hostilities, victims of terrorist attacks, physical or psychological persecution, witnessing scenes of cruelty, survival of natural disasters, and more, can strongly affect both children and adults. Pathological features of post-traumatic stress disorder that are manifested at molecular, cellular and whole-organism levels must be clearly understood for successful diagnosis, management, and minimizing of long-term outcomes associated with post-traumatic stress disorder. This article summarizes existing data on different post-traumatic stress disorder causes and symptoms, as well as effects on homeostasis, genetic instability, behavior, neurohumoral balance, and personal psychic stability. In particular, we highlight a key role of mitochondria and oxidative stress development in the severity and treatment of post-traumatic stress disorder. Excessive or prolonged exposure to traumatic factors can cause irreversible mitochondrial damage, leading to cell death. This review underlines the exceptional importance of data integration about the mechanisms and functions of the mitochondrial stress response to develop a three-dimensional picture of post-traumatic stress disorder pathophysiology and develop a comprehensive, universal, multifaceted, and effective strategy of managing or treatment post-traumatic stress disorder.

Stressor-Induced Temporal Cortisol Deficiency as a Primary Trigger for Adaptation to Stress

BACKGROUND

Inconsistencies in measurements of cortisol response to stress have caused disagreements in the direction of the change in cortisol concentrations immediately after the onset of stress. Researchers typically observe increased cortisol levels in response to a stressor, perceiving occasional decreases as a sign of possible disorders. Reports indicate the relative ease of standardizing a physical stressor compared with a mental stressor, and cross-stressor adaptation is observable only in elite athletes.

METHODS

We investigated the cortisol response to top-intensity physical exertion by analyzing the course of the cortisol response, the changes in this response resulting from adaptation to intense exercise, and the possible convergence between the cortisol changes and body fat content. We examined 16 male athletes, members of the Polish National Rowing Team, competing in the World Rowing Championships, in top form, of an average training experience of seven years. The measurements were performed before and after the training camp preparatory to the Championships. We performed the measurements before and after the training camp preparatory to the Championships.

RESULTS

Before the camp, the athletes consistently reacted to the exertion test with a decrease in cortisol concentration and elevated cortisol levels after rest compared with baseline. After the camp, the post-exertion cortisol decrease as well as the post-rest cortisol elevation was much smaller and less consistent.

CONCLUSIONS

The transient decrease in cortisol concentration at the onset of stress thus represents a physiological reaction, and the stress response counteracts the resulting cortisol deficiency to support cortisol availability during stress. Adaptation to stress enhanced this counteracting effect by (1) increasing the baseline cortisol concentration and (2) speeding up the response to its decline. This enhanced effect was boosted by adipose tissue.

The Link between Activities of Hepatic 11beta-Hydroxysteroid Dehydrogenase-1 and Monoamine Oxidase-A in the Brain Following Repeated Predator Stress: Focus on Heightened Anxiety

We investigated the presence of a molecular pathway from hepatic 11-βHSD-1 to brain MAO-A in the dynamics of plasma corticosterone involvement in anxiety development. During 14 days following repeated exposure of rats to predator scent stress for 10 days, the following variables were measured: hepatic 11-βHSD-1 and brain MAO-A activities, brain norepinephrine, plasma corticosterone concentrations, and anxiety, as reflected by performance on an elevated plus maze. Anxiety briefly decreased and then increased after stress exposure. This behavioral response correlated inversely with plasma corticosterone and with brain MAO-A activity. A mathematical model described the dynamics of the biochemical variables and predicted the factor(s) responsible for the development and dynamics of anxiety. In the model, hepatic 11-βHSD-1 was considered a key factor in defining the dynamics of plasma corticosterone. In turn, plasma corticosterone and oxidation of brain ketodienes and conjugated trienes determined the dynamics of brain MAO-A activity, and MAO-A activity determined the dynamics of brain norepinephrine. Finally, plasma corticosterone was modeled as the determinant of anxiety. Solution of the model equations demonstrated that plasma corticosterone is mainly determined by the activity of hepatic 11-βHSD-1 and, most importantly, that corticosterone plays a critical role in the dynamics of anxiety following repeated stress.

An Advanced Transcriptional Response to Corticosterone After Single Prolonged Stress in Male Rats

Stress-related neuropsychiatric disorders are often accompanied by dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis. In patients suffering from post-traumatic stress disorder (PTSD), increased sensitivity of glucocorticoid negative feedback has regularly been observed. The single prolonged stress (SPS) paradigm was developed to model increased negative feedback and other aspects of PTSD in rats. In this study, we used a setup that precluded the evaluation of negative feedback but rather served to test the hypothesis of the enhanced glucocorticoid receptor (GR) signaling in higher brain areas. We injected corticosterone or vehicle 7 days after SPS and evaluated plasma corticosterone, as well as gene expression in the dorsal hippocampus and amygdala. We observed a strikingly rapid change in the expression of established GR target genes (t = 30 min) only in the SPS group on exogenous corticosterone injection. Our results extend the notion of increased GR sensitivity in PTSD to include transcriptional responses in the hippocampus.